JP2022008185A - Pulley structure - Google Patents

Abstract

To provide a pulley structure which is adaptable to an ISG system by securing a coil spring type clutch function bi-directionally without causing size enlargement in a rotation axial direction, and can suppress an excessive increase and a variation of belt tension even if excessive torque is inputted into an outer rotating body.SOLUTION: A pulley structure 1 comprises an outer rotating body 2 wound with a belt, an inner rotating body 3 which can relatively rotate with respect to the outer rotating body 2, a spring 4 arranged between the outer rotating body 2 and the inner rotating body 3, and a spring 5 arranged in parallel with the inside of the spring 4 in a radial direction. The spring 4 has a rear-end side region A1 contacting with the outer rotating body 2 by an own elastic restoration force in a diameter-expanded direction, a front-end side region B1 contacting with the inner rotating body 3 by an own elastic restoration force in a diameter-contracted direction, and an intermediate region C1 of a free portion. The spring 5 has a rear-end side region A2 contacting with the spring 4 by an own elastic restoration force in a diameter-expanded direction, a front-end side region B2 contacting with the inner rotating body 3 by an own elastic restoration force in a diameter-contracted direction, and an intermediate region C2 of a free portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pulley structure with a coil spring.

In an auxiliary drive unit that drives auxiliary equipment such as an alternator by the power of an engine such as an automobile, a belt is hung over a pulley connected to the drive shaft of the auxiliary equipment such as an alternator and a pulley connected to the crank shaft of the engine. Then, the torque of the engine is transmitted to the auxiliary machine through this belt. In particular, for the pulley connected to the drive shaft of the alternator having a larger inertia than other auxiliary machines, for example, the pulley structure of Patent Document 1 capable of absorbing the rotational fluctuation of the crank shaft is used.

The pulley structure of Patent Document 1 includes an outer rotating body and an inner rotating body provided inside the outer rotating body and capable of relative rotation with respect to the outer rotating body, and is a belt wound around the outer rotating body. From the viewpoint of slip prevention and the like, a one-way clutch is provided between the outer rotating body and the inner rotating body to transmit or cut off torque in one direction. This one-way clutch is a coil spring type clutch including a torsion coil spring. A one-way clutch (coil spring) is used to relatively rotate the outer rotating body (connected to the drive shaft such as the crank shaft via the belt) and the inner rotating body (connected to the driven body such as auxiliary equipment via the shaft). Therefore, the difference in rotation speed between the outer rotating body and the inner rotating body is absorbed.

In the conventional pulley structure having a coil spring type clutch, the pulley structure of Patent Document 1 (for example, the fifth embodiment) (hereinafter, "conventional 1 pulley structure" or simply "conventional 1") (FIG. 9). (Refer to), a pressure contact surface (clutch engagement surface) that is radially opposed to the rear end side (one end side) of the coil spring is formed on the rear end side (one end side) of the outer rotating body, and the rear end of this coil spring. The end side (one end side) is strongly frictionally engaged with the pressure contact surface of the outer rotating body, and the front end side (the other end side) of the inner rotating body is in the circumferential direction with the front end surface (the other end surface) 4a of the coil spring. The facing contact surface 403d is formed (not shown) (see FIG. 14 of Patent Document 1), and the front end surface (the other end surface) 4a of the coil spring presses the contact surface 403d of the inner rotating body in the circumferential direction. , The torque input to the outer rotating body can be transmitted to the inner rotating body via the coil spring.

Further, when the engine is cold-started, an excessive torque is input to the outer rotating body, the diameter of the free portion (middle region) of the coil spring is expanded, and the free part (outer peripheral surface) of the coil spring is the outer rotating body. When it comes into contact with the inner peripheral surface (annular surface 2b), the locking mechanism operates momentarily (strong friction engagement and lock state), and restricts (prevents) torsional deformation of the coil spring in the larger diameter direction. , Stop). This makes it possible to prevent an overload on the one-way clutch (coil spring).

By the way, recently, a system (ISG-compatible auxiliary drive belt system equipped with a motor generator (ISG)) that stops the engine in an idle state such as waiting for a signal and restarts the engine after this idle stop (hereinafter, The number of vehicles equipped with an "ISG system") is increasing, and the demand for support for the ISG system is increasing.

The ISG (Integrated Starter Generator) has both a function as a motor (ISG operates as a starter motor) and a function as a generator, and is provided at the position of a conventional alternator in an auxiliary drive belt system. In ISG, the internal rotational inertia mass (inertial mass) including the drive shaft is larger than the conventional alternator due to its characteristics. When the auxiliary drive belt system is an ISG system, the pulley structure (ISG pulley) connected to the drive shaft of the ISG is a drive pulley (for example, during cranking before the initial explosion when the engine is started by the ISG). It can be (during assisted driving by ISG) and a driven pulley (for example, after the first explosion at the time of starting the engine by ISG, during power generation by ISG).

For this reason, the torque input to the pulley structure (hereinafter referred to as "input torque") will increase in both directions (see the definition described later) compared to the conventional method (when not compatible with ISG) (Table 1). reference).

(Correspondence to ISG system (requirements))

When applying the configuration of the pulley structure of the conventional 1 (FIG. 9) to the ISG system, it corresponds to the increase in the spring constant (inclination of the torque curve) and the twist angle of the coil spring in both directions. (Fig. 7), after thickening the spring wire of the coil spring and increasing the number of turns, the torque (slip torque Ts) (absolute value) when the one-way clutch operates and shuts off the torque is set to a predetermined level. The design items related to the change of these set torques are appropriately determined so that the torque when the lock mechanism operates (locking torque TL) can be raised to a predetermined level (see Table 2). It was considered that the design should be changed (Fig. 10) (this configuration is referred to as "conventional 2").

(Set torque (compared to level))

Japanese Unexamined Patent Publication No. 2014-114497 Japanese Unexamined Patent Publication No. 2008-057763

However, when the conventional pulley structure (FIG. 10) is applied to the ISG system, among the ISG functions (driving running patterns i to iii), (ii) assisted running and (iii) power generation can be dealt with. However, (i) when the lock mechanism is activated due to engine start (excessive torque input), the belt tension increases excessively and the belt tension fluctuates excessively (and the durability of the belt system). (See Table 3).

Therefore, the lock mechanism is not activated, and instead, the coil spring type clutch function is secured in the direction when the conventional lock mechanism is activated (for example, the diameter expansion direction of the coil spring) (the lock mechanism is activated). It is conceivable to have a configuration that does not, and a configuration that can secure the coil spring type clutch function in both directions).

For example, in Patent Document 2 (for example, the seventh embodiment, paragraphs 0205 to 0228, FIGS. 25 to 29), a portion other than the end portion of the coil spring has a diameter at the time of relative rotation between the outer rotating body and the inner rotating body. Even if it is deformed in the direction in which the size changes (diameter expansion direction, diameter reduction direction of the coil spring), it is configured so that it does not come into contact with either the outer rotating body or the inner rotating body (see paragraph 0137, etc., Fig. 25, etc.). Further, with the pulley structure stopped, each of the end portions (one end side and the other end side) of the coil spring and the portion of the outer rotating body or the inner rotating body that are in radial facing contact with the end portion. Are frictionally engaged, and when a predetermined or greater torque is transmitted between the outer rotating body and the inner rotating body in both directions (diameter expansion or contraction direction of the coil spring), the end portion of the coil spring. Each of the (one end side and the other end side) is in an disengaged state where it slides (slips) with the outer rotating body or the inner rotating body, and the torque is transmitted between the outer rotating body and the inner rotating body. A configuration that can be blocked is described (particularly, paragraphs 0221 to 0222).

However, in the pulley structure (1st to 8th embodiments) disclosed in Patent Document 2, each of the end portions (one end side and the other end side) of the coil spring is frictionally engaged with the outer rotating body or the inner rotating body. The embodiment is either (A) or (B) below.
(A) When the diameter expansion force (self-elastic restoring force in the diameter expansion direction) of the end of the coil spring is applied (that is, the end of the spring is pressure-welded to the inner peripheral surface of the outer or inner rotating body on either side. Aspects)
(B) In the case of the contraction force (self-elastic restoring force in the contraction direction) at the end of the coil spring (that is, the end of the spring is in pressure contact with the outer peripheral surface of the outer or inner rotating body on either side. Aspects)
That is, the direction of the force (diameter direction) in which the end portion of the coil spring is in pressure contact with the outer rotating body or the inner rotating body is the same on one end side and the other end side (note that it may be "reverse direction"). Is neither mentioned nor mentioned).

Therefore, in both directions (diameter expansion or contraction direction of the coil spring), the frictional engagement state (pressure contact state of the coil spring) between the coil spring and the outer rotating body and the inner rotating body is the twist angle of the coil spring. The larger the
(A) The pressure contact force with respect to the outer rotating body or the inner rotating body increases on either side of the end portion (one end side or the other end side) of the coil spring, and is strongly frictionally engaged with the outer rotating body or the inner rotating body. Let's go,
(B) On either side of the end (one end side, the other end side) of the coil spring, the pressure contact force with respect to the outer rotating body or the inner rotating body decreases, and does it start sliding (engagement) with the outer rotating body or the inner rotating body? It will be in either state ((a) or (b)).
That is, it is considered that the end portion of the coil spring brings about the same action ((a) or (b) above) on one end side and the other end side.

Here, in the case of (a) above, in order to lead the clutch to the disengaged state in both directions (in the direction of expansion or contraction of the coil spring), an unexpectedly excessive torque (external force) is externally rotated. It is difficult unless it is input to the body (for example, only when the bearing provided in the auxiliary machine such as an alternator is damaged and the drive shaft of the auxiliary machine becomes non-rotatable).

Therefore, it is presumed that the pulley structure disclosed in Patent Document 2 can substantially secure the coil spring type clutch function in only one direction (the coil spring type clutch function cannot be secured in both directions).

Next, in the pulley structure of the conventional 2 (FIG. 10), the size is naturally increased in the rotation axis direction (and the axial direction parallel to the crank axis of the engine) as compared with the conventional 1, and the alternator overhang (bearing) is increased. As the amount of overhang from the bearing increases, the bearing size is increased to supplement the bearing strength, and as a result, the alternator becomes even larger. That is, if the basic configuration (spring number 1) of the conventional pulley structure (patent document 1 etc.) is maintained, the size of the pulley structure in both directions will be increased in the direction of the rotation axis in the case of dealing with an excessive input torque. It was considered that there is a limit to secure the mounting space for the pulley structure and the alternator, and to be able to raise the allowable torque in both directions.

Therefore, an object of the present invention is to secure a coil spring type clutch function in both directions without inviting an increase in size in the rotation axis direction, to be compatible with an ISG system, and to input an excessive torque to an outer rotating body. However, it is an object of the present invention to provide a pulley structure capable of effectively suppressing an excessive increase in belt tension and an excessive fluctuation in belt tension.

The present invention includes a cylindrical outer rotating body around which a belt is wound.
An inner rotating body provided inside in the radial direction of the outer rotating body and capable of relative rotation with respect to the outer rotating body about the same rotation axis as the outer rotating body.
A first coil spring provided between the outer rotating body and the inner rotating body and compressed in the axial direction along the rotation axis, and a first coil spring.
A pulley structure comprising a second coil spring that is juxtaposed radially inward with respect to the first coil spring and is axially compressed along the axis of rotation.
The first coil spring is
On one end side, the first one end side region where the outer peripheral surface comes into contact with one of the outer rotating body and the inner rotating body by the self-elastic restoring force in the diameter expansion direction in a state where no external force is applied to the pulley structure. When,
On the other end side, the inner peripheral surface comes into contact with the other of the outer rotating body and the inner rotating body by the self-elastic restoring force in the radial direction in a state where no external force is applied to the pulley structure. The end area and
Between the first one end side region and the first other end side region, both of the outer rotating body and the second coil spring during relative rotation between the outer rotating body and the inner rotating body. Has a first middle region that does not come into contact,
When the first coil spring is twisted in the radial direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the outer peripheral surface of the first one end side region is said to be the outer peripheral surface. Sliding with respect to one of the outer rotating body and the inner rotating body,
When the first coil spring is twisted in the diameter expansion direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the inner peripheral surface of the first other end side region is formed. , Sliding with respect to the other of the outer rotating body and the inner rotating body,
The second coil spring is
On one end side, the second end side where the outer peripheral surface contacts the first end side region of the first coil spring by the self-elastic restoring force in the diameter expansion direction in a state where no external force is applied to the pulley structure. Area and
On the other end side, the inner peripheral surface comes into contact with the outer rotating body and the other side of the inner rotating body by the self-elastic restoring force in the radial direction in a state where no external force is applied to the pulley structure. The other end area and
Between the second one end side region and the second other end side region, both the first coil spring and the inner rotating body during relative rotation between the outer rotating body and the inner rotating body. Has a second middle region that does not come into contact,
When the second coil spring is twisted in the radial direction and a torque of a predetermined value or more is transmitted between the outer rotating body and the inner rotating body, the outer peripheral surface of the second one end side region is said to be the outer peripheral surface. Sliding with respect to the outer rotating body and the inner rotating body via the first one end side region of the first coil spring,
When the second coil spring is twisted in the diameter expansion direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the inner peripheral surface of the second other end side region becomes. , The pulley structure is configured to slide with respect to the other of the outer rotating body and the inner rotating body.

The pulley structure connected to the drive shaft of the ISG system includes a drive pulley (for example, during cranking before the initial explosion at the time of engine start by ISG, during assisted running by ISG) and a driven pulley (for example, engine start by ISG). After the first explosion at the time, it can be the time of power generation by ISG). In order to correspond to the bidirectional torque input to this pulley structure, the spring wire of the coil spring is made thicker in order to increase the spring constant and the torsion angle of the coil spring compared to the conventional method (conventional 1). Moreover, it is necessary to increase the number of turns.
However, in a pulley structure having only one coil spring, when trying to increase the spring constant, the size of the cross section of the spring wire passing through the rotation axis of the outer rotating body and along the direction parallel to the rotation axis. Tends to increase, and the pulley structure becomes large.
Therefore, by using two coil springs, a first coil spring and a second coil spring, the second coil spring is arranged side by side in the radial direction of the first coil spring. The size of the cross section of the spring wire of the first coil spring that passes through the rotation axis of the outer rotating body and along the direction parallel to the rotation axis can be made smaller than that of the conventional 2. Further, the cross-sectional area of the spring wire in the second coil spring is significantly smaller than that of the first coil spring because the inner diameter is smaller than that of the first coil spring (the inner diameter is smaller than that of the first coil spring). If it is small, the spring constant will be large accordingly. Therefore, in order to set the spring constant of the second coil spring at a low level, the cross-sectional area of the spring wire should be significantly smaller than that of the first coil spring. 2 coil springs can be formed).
Therefore, according to the above configuration, it is possible to prevent the pulley structure from becoming larger in the direction of the rotation axis (effect 1).

Further, in both directions (diameter expansion or contraction direction of the two coil springs), each end of the two coil springs (first coil spring and second coil spring) becomes an outer rotating body or an inner rotating body. The direction of the pressure contacting force (diameter direction) can be reversed (bias relationship) between one end side and the other end side.
Therefore, in both directions, the torsional angle (absolute value) of the two coil springs is the frictional engagement state (pressure contact state of the two coil springs) between the two coil springs and the outer rotating body and the inner rotating body. The larger the value, the more the following states (a) and (b) are obtained. (A) One end side of each of the two coil springs (outer peripheral surface of the first one end side region, outer peripheral surface of the second one end side region) and each other end side (inner peripheral surface of the first other end side region, second and others). One of the inner peripheral surfaces of the end side region) has an increased pressure contact force with respect to the outer rotating body or the inner rotating body, and is strongly frictionally engaged with one of the outer rotating body and the inner rotating body. Each one end side (outer peripheral surface of the first one end side region, outer peripheral surface of the second one end side region) and each other end side (inner peripheral surface of the first other end side region, inner peripheral surface of the second other end side region) On the other side, the pressure contact force with respect to the outer rotating body or the inner rotating body decreases, and the other of the outer rotating body and the inner rotating body starts to slide (disengage).
That is, each end of the two coil springs has one end side (outer peripheral surface of the first one end side region, outer peripheral surface of the second one end side region) and each other end side (inner peripheral surface of the first other end side region). , The inner peripheral surface of the second other end side region), the opposite action (the above (a) and (b)) is brought about.
As a result, (i) when the normal torque (torsional torque of the two coil springs within the range that does not reach the set slip torque) is input, the two coil springs are torsionally deformed in both directions (diameter expansion or contraction direction). At that time, the torque is transmitted between the outer rotating body and the inner rotating body by engaging with the outer rotating body and the inner rotating body.
On the other hand, (ii) when an excessive torque (twisting torque of two coil springs equal to or higher than the set slip torque) is input, the two coil springs are in both directions (diameter expansion or contraction direction) with the outer rotating body. When a torque equal to or higher than a predetermined value is transmitted to and from the rotating body, the engagement with the outer rotating body or the inner rotating body is disengaged, and the torque between the outer rotating body and the inner rotating body is increased. Block transmission.
As a result, for example, even if an excessive torque (for example, a torque of slip torque of 30 Nm or more in the diameter expansion direction) is input to the outer rotating body at the time of cold starting of the engine by ISG, the torque is input from the outer rotating body. No impact load (excessive rotational braking force) acts on the belt (tension side) on the side, and it is possible to suppress an excessive increase in belt tension and an excessive fluctuation in belt tension.
On the contrary, even if the engine is unexpectedly stopped (stall) due to derailment while the engine is running (for example, even if a slip torque of 45 Nm or more is input in the diameter reduction direction), the belt tension ( The tension side) does not drop excessively, and it is possible to prevent the belt from slipping.
As a result, as shown in (i) and (ii) above, the coil spring type clutch function (torque transmission or disconnection) can be secured in both directions (diameter expansion direction and diameter reduction direction of the two coil springs). (Effect 2).

Further, the first coil spring has a first middle region which is a free portion that does not come into contact with either the outer rotating body or the second coil spring during the relative rotation between the outer rotating body and the inner rotating body. The second coil spring also has a second middle region which is a free portion that does not come into contact with either the first coil spring or the inner rotating body at the time of relative rotation between the outer rotating body and the inner rotating body. This makes it possible to reliably prevent the locking mechanism from operating in both directions (in the direction of expansion or contraction of the two coil springs). As a result, for example, even if an excessive torque is input to the outer rotating body, the two coil springs (clutches) are prevented from falling into a state of being strongly frictionally engaged with the outer rotating body or the inner rotating body (locked state). Can be done (effect 3).

Further, in the present invention, in a state where no external force is applied to the pulley structure, the self-elastic restoring force in the diameter expansion direction in the first one end side region is the diameter reduction direction in the first end side region. It is larger than the self-elastic restoring force of
In a state where no external force is applied to the pulley structure, the self-elastic restoring force in the expansion direction in the second one end side region is larger than the self-elastic restoring force in the contraction direction in the second other end side region. It may be characterized in that it is configured to be large.

According to the above configuration, the torque (slip torque Tsa1, Tsa2) (absolute value) at which the clutch operates when the two coil springs (first coil spring and second coil spring) are twisted in the radial direction It is possible to ensure that the torque (slip torque Tsb1, Tsb2) (absolute value) at which the clutch operates when the two coil springs are twisted in the radial direction is set to be larger than the torque (absolute value).
As a result, the above pulley structure is replaced with an ISG pulley (when the pulley structure is a drive pulley (for example, during cranking before the first explosion at the time of starting the engine by ISG, when assisted by ISG), and a driven pulley (when the pulley structure is assisted by ISG). For example, by applying it to the ISG system as (playing both roles (after the first explosion at the time of engine start by ISG) and at the time of power generation by ISG), in each running pattern at the time of engine start, assisted running, and power generation. It can be suitably dealt with (effect 4).

It is sectional drawing of the pulley structure of this embodiment. (A) is a cross-sectional view taken along the line I-I of the pulley structure of FIG. (B) is a cross-sectional view taken along the line II-II of the pulley structure of FIG. FIG. 3 is a cross-sectional view taken along the line III-III of the pulley structure of FIG. It is a figure explaining the state at the time of operation of the pulley structure (particularly the 1st coil spring and the 2nd coil spring) of this embodiment. (A) When the pulley structure is stopped (when no external force is applied to the pulley structure) (b) When accelerating the outer rotating body (c) When decelerating the outer rotating body It is a graph which shows the relationship between the torsion angle and the torsion torque of two coil springs in the pulley structure of this embodiment. It is a graph which shows the relationship between the torsion angle and the torsion torque of a coil spring in the pulley structure (FIG. 9) of the conventional 1. It is a graph which shows the relationship between the torsion angle and the torsion torque of a coil spring in the pulley structure (FIG. 10) of the conventional 2. It is an exploded view of the pulley structure of this embodiment. FIG. 5 is a cross-sectional view of a conventional pulley structure (fifth embodiment of Patent Document 1: a support protrusion 403e is provided on an inner peripheral surface of an outer cylinder portion). It is sectional drawing of the conventional 2 pulley structure (the first embodiment of patent document 1: no support protrusion 403e on the inner peripheral surface of the outer cylinder part). It is a schematic block diagram of an engine bench test machine. It is a schematic block diagram of the engine bench test machine (the auxiliary machine drive belt system corresponding to ISG including the pulley structure of this embodiment). It is a graph which shows the time-series change of the belt tension (dynamic belt tension) which concerns on Example 1 and Comparative Example 1.

(Embodiment)
Hereinafter, the pulley structure 1 according to the embodiment of the present invention will be described.

(Auxiliary drive belt system)
The pulley structure 1 of the present embodiment is installed on a drive shaft of a motor generator (ISG) in an auxiliary drive belt system (not shown) of an automobile.

(Pulley structure 1)
As shown in FIGS. 1 and 8, the pulley structure 1 includes an outer rotating body 2, an inner rotating body 3, a first coil spring 4 (hereinafter, simply referred to as “spring 4”), and a second coil spring 5 (hereinafter, simply referred to as “spring 4”). Hereinafter, the term "spring 5") and the end cap 6 are included. Hereinafter, the right side in FIG. 1 will be described as one end (rear end), and the left side will be described as the other end (front end). The end cap 6 is arranged on the other end side (front end side) of the outer rotating body 2 and the inner rotating body 3. The springs 5 are arranged side by side in the radial direction of the spring 4.

The terms used in the description of the pulley structure 1 are defined as follows.
-"Bidirectional" refers to the expansion direction and the reduction direction of the spring 4 and the spring 5, and is positive when the two rotating bodies (outer rotating body 2 and inner rotating body 3) rotate relative to each other. When pointing in the direction and the opposite direction ((a) and (b) below), the direction of transmission of torque between the outer rotating body 2 and the inner rotating body 3 is bidirectional ((i) and (ii) below). , May be said.
(a). When the outer rotating body 2 rotates relative to the inner rotating body 3 in the same direction (positive direction) (when the outer rotating body 2 accelerates)
(b). When the outer rotating body 2 rotates relative to the inner rotating body 3 in the opposite direction (reverse direction) (when the outer rotating body 2 decelerates)
(i). When the torque input to the inner rotating body 3 is transmitted to the outer rotating body 2 (when operating as a drive pulley) (At this time, the inner rotating body 3 accelerates to cause the spring 4 and the spring. 5 is twisted in the radial direction)
(ii). When the torque input to the outer rotating body 2 is transmitted to the inner rotating body 3 (when operating as a driven pulley) (At this time, the outer rotating body 2 accelerates to cause the spring 4 and the spring. 5 is twisted in the direction of expansion)

-"Slip torque" (Ts) is the torsional torque of the spring when the clutch (spring) is in the disengaged state (sliding state).
-The "clutch engaging part" is the part where the clutch (spring) engages or disengages in order to transmit or disengage torque.
-The effective number of turns is the number of turns in the range excluding the part where the spring is fixed from the total length of the spring. The larger the effective number of turns, the smaller the spring constant.
-Normal torque is the torsional torque of the spring within the range that does not reach the set slip torque.
・ Excessive torque is the torsional torque of the spring that exceeds the set slip torque.

(Outer rotating body 2 and inner rotating body 3)
The outer rotating body 2 and the inner rotating body 3 are both substantially cylindrical and have the same rotation axis. The rotating shafts of the outer rotating body 2 and the inner rotating body 3 are the rotating shafts of the pulley structure 1, and are hereinafter simply referred to as "rotating shafts". Further, the direction of the axis of rotation is simply referred to as "axial direction". The inner rotating body 3 is provided inside the outer rotating body 2 in the radial direction, and can rotate relative to the outer rotating body 2. A belt is wound around the outer peripheral surface of the outer rotating body 2.

The inner rotating body 3 has a cylinder body 3a and an outer cylinder portion 3b arranged outside the other end (front end) of the cylinder body 3a. A drive shaft S such as an alternator is fitted to the cylinder body 3a. A support groove portion 3c is formed between the outer cylinder portion 3b and the cylinder body 3a. The inner peripheral surface of the outer cylinder portion 3b and the outer peripheral surface of the cylinder body 3a are connected via a first groove bottom surface 3d and a second groove bottom surface 3e, which are the bottom surfaces of the support groove portion 3c.

The bottom surface 3d of the first groove has a flat surface orthogonal to the axial direction, and abuts on the counterbore surface Be4 of the spring 4. Further, the second groove bottom surface 3e is provided on the cylinder body 3a side and at one end side (rear end side) of the spring 4 for about two turns, with respect to the first groove bottom surface 3d. Like the first groove bottom surface 3d, the second groove bottom surface 3e has a flat surface orthogonal to the axial direction and abuts on the counterbore surface Be5 of the spring 5.

The support groove portion 3c of the inner rotating body 3 has a contact surface facing the front end surface 4a of the spring 4 and the front end surface 5a of the spring 5 (see FIG. 2) in the circumferential direction, as in the conventional pulley structure 1. Or, the bottom surface of the spiral groove is not formed. The reason is that the spring 4 and the spring 5 can slide (slip) with the internal rotating body 3 when the clutch is disengaged.

A rolling bearing 7 is interposed between the inner peripheral surface of the rear end of the outer rotating body 2 and the outer peripheral surface of the cylinder body 3a. A slide bearing 8 is interposed between the inner peripheral surface of the front end of the outer rotating body 2 and the outer peripheral surface of the outer cylinder portion 3b. The outer rotating body 2 and the inner rotating body 3 are connected so as to be relatively rotatable by the rolling bearing 7 and the sliding bearing 8.

An annular thrust plate 10 is arranged between the outer rotating body 2 and the inner rotating body 3 on the front end side of the rolling bearing 7. The front end surface of the thrust plate 10 forms a flat surface orthogonal to the axial direction. The reason is that the spring 4 and the spring 5 can slide (slip) with the thrust plate 10 when the clutch is disengaged. When assembling the pulley structure 1, the thrust plate 8 and the rolling bearing 7 are fitted onto the cylinder body 3a in this order.

In the pulley structure 1, a space 9 is formed between the outer rotating body 2 and the inner rotating body 3 on the front end side of the thrust plate 10. A spring 4 and a spring 5 are housed in this space 9. The space 9 is formed between the inner peripheral surface of the outer rotating body 2 and the inner peripheral surface of the outer cylinder portion 3b, and the outer peripheral surface of the cylinder main body 3a.

The inner diameter of the outer rotating body 2 decreases in two steps toward the rear end. The inner peripheral surface of the outer rotating body 2 in the smallest inner diameter portion is referred to as a pressure contact surface a1, and the inner peripheral surface of the outer rotating body 2 in the second smallest inner diameter portion is referred to as an annular surface 2b. The inner diameter of the outer rotating body 2 on the pressure contact surface a1 is smaller than the inner diameter of the outer cylinder portion 3b. The inner diameter of the outer rotating body 2 on the annular surface 2b is equal to or larger than the inner diameter of the outer cylinder portion 3b.

As shown in FIG. 1, the outer diameter of the cylinder body 3a has four different sizes from the front end side to the rear end side. The outer peripheral surface of the cylinder body 3a on the frontmost end side has the largest outer diameter and is referred to as a pressure contact surface b1 that abuts on the inner peripheral surface of the spring 4. The outer peripheral surface of the cylinder body 3a on the rear end side of the pressure contact surface b1 has an outer diameter smaller than that of the pressure contact surface b1 and is referred to as a pressure contact surface b2 that abuts on the inner peripheral surface of the spring 5. The outer peripheral surface of the cylinder body 3a on the rear end side of the pressure contact surface b2 is called an annular surface 3f, and the outer diameter is smaller than the pressure contact surface b2. The outer peripheral surface of the cylinder body 3a on the rear end side (most rear end side) of the annular surface 3f is called the annular surface 3g, and the outer diameter is smaller than the pressure contact surface b2 and larger than the annular surface 3f.

(First coil spring 4)
The spring 4 is a torsion coil spring formed by spirally winding (coiling) a spring wire (spring wire material). The spring 4 is left-handed (counterclockwise from the front end surface 4a toward the rear end surface 4e), and has a constant diameter over the entire length in a state where no external force is applied. The number of turns N of the spring 4 is, for example, 6 to 10 turns (in the present embodiment, the number of turns N of the spring 4 is 9 turns). The spring wire of the spring 4 has a rectangular shape (substantially rectangular) in cross-sectional shape (cross-sectional shape passing through the rotation axis and along the direction parallel to the rotation axis). The four corners in the cross section of the spring wire have a chamfered shape (for example, an R surface or a C surface having a radius of curvature of about 0.3 mm).

For example, in the present embodiment, the number of turns N of the spring 4 is set to 9 (Example 1 described later).
Further, the inner diameter of the spring 4 is the same as that of the conventional 1 and the conventional 2. The cross-sectional area of the spring wire of the spring 4 corresponds to each level of the spring constant (spring 4, conventional 1, conventional 2) (see FIGS. 5, 6, and 7), and is approximately intermediate between the conventional 1 and the conventional 2. (See Table 4 of Examples described later for the index).

(Second coil spring 5)
The spring 5 is a torsion coil spring formed by spirally winding (coiling) a spring wire (spring wire material). The spring 5 is left-handed (counterclockwise from the front end surface 5a toward the rear end surface 5e), and as shown in FIG. 8, in a state where no external force is applied, the spring 5 has the rear end side region A2 (for example, 3 turns). The front end side region B2 and the middle region C2 (for example, a total of 6 turns) are formed in two stages in diameter. The diameter of the rear end side region A2 is significantly larger than the diameter of the front end side region B2 and the middle region C2. Further, the inner diameter of the spring 5 is smaller than the inner diameter of the spring 4. The number of turns N of the spring 5 is, for example, 6 to 10 turns (in the present embodiment, the number of turns N of the spring 5 is 9 turns: the rear end side region A2 has 3 turns, the front end side region B2 and the middle region. 6 rolls of C2). The spring wire of the spring 5 has a rectangular cross-sectional shape (substantially square). The four corners in the cross section of the spring wire have a chamfered shape (for example, an R surface or a C surface having a radius of curvature of about 0.3 mm).

For example, in the present embodiment, the number of turns N of the spring 5 is 9 (the rear end side region A2 has 3 turns, the front end side region B2 and the middle region C2 have 6 turns) (Example 1 described later).
Further, the inner diameter of the spring 5 is smaller than that of the spring 4. The inner diameter of the spring 5 in the state of not receiving the external force is the front end side region B2 (for 2 turns) and the middle region C2 (for 4 turns) with respect to the inner diameter 100 (index) of the spring 4 in the state of not receiving the external force. ) Is 67 (index), and the rear end side region A2 (for 3 turns) is 79 (index).
The cross-sectional area of the spring wire of the spring 5 corresponds to the level of the spring constant (spring 4, spring 5) (see FIG. 5), and because the inner diameter is smaller than that of the spring 4, it is significantly smaller than that of the spring 4 (about 40%). ).

(Relationship between the rear end side region A1 of the spring 4 and the rear end side region A2 of the spring 5 and the pressure contact surface a1 (clutch engaging portion a1): FIGS. 1 and 3).
The relationship between the rear end side region A1 of the spring 4 and the rear end side region A2 of the spring 5 and the pressure contact surface a1 (clutch engaging portion a1) is as follows: the entire spring of the spring 4 and the spring 5, the spring 4 alone, and the spring 5. It will be explained separately.

(Whole spring of spring 4 and spring 5)
The pressure contact force of the rear end side region A1 of the spring 4 with respect to the pressure contact surface a1 is set to Fa1, and the pressure contact surface a2 of the rear end side region A2 of the spring 5 (the rear end side region A1 of the spring 4 and the rear end side region A2 of the spring 5 are combined with each other. Assuming that the pressure contact force with respect to the abutting surface) is Fa2, the target torque curve (see FIG. 5), particularly the slip torque Tsa (see FIG. 5), in the radial direction of the entire spring (simply the entire spring) of the spring 4 and the spring 5 Based on the magnitude of the sum of Tsa1 and Tsa2 (absolute value), the torque (absolute value) decreases as the torsion angle (absolute value) of the entire spring (spring 4 and spring 5) increases during normal torque input. A state in which no external force is applied to the pulley structure 1 (stopping of the pulley structure 1) so that the friction torque TAa (absolute value) to be applied is maintained at a level higher than the slip torque Tsa (set value). Time), the magnitude of the resultant force (Fa1 + Fa2) between the pressure contact force Fa1 and the pressure contact force Fa2 (see FIG. 4A), and the following design items relating to the spring 4 and the spring 5 are appropriately determined.

(Spring 4 alone)
Assuming that the pressure contact force of the rear end side region A1 of the spring 4 with respect to the pressure contact surface a1 is Fa1, the target torque curve (see FIG. 5), particularly the slip torque Tsa1 (absolute value), in the radial direction of the spring 4 Based on the magnitude, the friction torque TA1a1 (absolute value), in which the torque (absolute value) decreases as the torsion angle (absolute value) of the spring 4 increases during normal torque input, is the slip torque Tsa1 (set value). The magnitude of the pressure contact force Fa1 (see FIG. 4A) in a state where no external force is applied to the pulley structure 1 (when the pulley structure 1 is stopped) so as to maintain the level higher than that of the pulley structure 1. That is, the design items such as the radial and axial lengths of the pressure contact surface a1 (clutch engaging portion a1) and the number of turns of the spring 4 (rear end side region A1) are appropriately determined.

(Spring 5 alone)
Assuming that the pressure contact force of the rear end side region A2 of the spring 5 with respect to the pressure contact surface a2 is Fa2, the target torque curve (see FIG. 5) in the contraction direction of the spring 5, particularly the slip torque Tsa2 (absolute value). Based on the magnitude, the friction torque TA2a2 (absolute value), in which the torque (absolute value) decreases as the torsion angle (absolute value) of the spring 5 increases during normal torque input, is the slip torque Tsa2 (set value). The magnitude of the pressure contact force Fa2 in the state where no external force is applied to the pulley structure 1 (when the pulley structure 1 is stopped) so as to maintain the level higher than that (see FIG. 4A). That is, the design items such as the radial and axial lengths of the pressure contact surface a2 and the number of turns of the spring 5 (rear end side region A2) are appropriately determined.

For example, in this embodiment, it is designed as follows (Example 1 described later).
・ Slip torque Tsa (set value) in the reduced diameter direction: -45N ・ m
* Equal to the sum of Tsa1 (below) and Tsa2 (below).
* The magnitude of the slip torque Ts in the conventional torque curve 2 (see FIG. 7) is set to be about the same.
* The allowable torque Tm2 (FIG. 5) was set to -40 Nm as in the conventional case 2 (Tm2 in FIG. 7).
・ Slip torque Tsa1 in the reduced diameter direction (set value): -33N ・ m
・ Slip torque Tsa2 in the reduced diameter direction (set value): -12N ・ m
Number of turns of the rear end side region A1 of the spring 4: Within the range in which the torsional torque of the spring 4 does not reach the slip torque Tsa1 in the radial direction, the spring 4 (rear end side region A1) and the pressure contact surface a1 (clutch). The number of turns of the rear end side region A1 is set to 3 turns (however, the friction engagement portion is 2.5) to the same extent as the conventional 2 so that the frictional engagement state can be maintained between the engagement portion a1) and the A1a1. Roll).
Number of turns of the rear end side region A2 of the spring 5: Within the range in which the torsional torque of the spring 5 does not reach the slip torque Tsa2 in the radial direction, the spring 5 (rear end side region A2) and the pressure contact surface a2 In order to maintain the frictionally engaged state between A2a2 and A2a2, the number of turns of the rear end side region A2 is set to 3 turns (the frictionally engaged portion is also 3 turns) to the same extent as the spring 4.
The radial length of the pressure contact surface a1 (clutch engaging portion a1) (inner diameter of the outer rotating body 2): about 93 with respect to the outer diameter 100 (index) of the spring 4 in a state where no external force is applied.
Axial length of the pressure contact surface a1 (clutch engaging portion a1): A length corresponding to the number of turns of the spring 4 (rear end side region A1) in contact with the other.
Radial length of pressure contact surface a2 (rear end side region A1 of spring 4) (inner diameter of rear end side region A1): outer diameter 100 of spring 5 (rear end side region A2) in a state where no external force is applied. It was set to about 93 with respect to (index).
Axial length of the pressure contact surface a2 (rear end side region A1 of the spring 4): A length corresponding to the number of turns of the spring 5 (rear end side region A2) in contact with each other.

(Relationship between the front end side region B1 of the spring 4 and the pressure contact surface b1 (clutch engagement portion b1), and the relationship between the front end side region B2 of the spring 5 and the pressure contact surface b2 (clutch engagement portion b2): FIG. 1, Figure 2)
The relationship between the front end side region B1 of the spring 4 and the pressure contact surface b1 (clutch engagement portion b1), and the relationship between the front end side region B2 of the spring 5 and the pressure contact surface b2 (clutch engagement portion b2) are described with respect to the spring 4 and the pressure contact surface b2. The whole spring of the spring 5, the spring 4 alone, and the spring 5 alone will be described separately.

(Whole spring of spring 4 and spring 5)
Assuming that the pressure contact force of the front end side region B1 of the spring 4 with respect to the pressure contact surface b1 is Fb1 and the pressure contact force of the front end side region B2 of the spring 5 with respect to the pressure contact surface b2 is Fb2, the target torque curve in the diameter expansion direction of the entire spring ( (See FIG. 5), in particular, the torsion angle (absolute) of the entire spring (spring 4 and spring 5) at the time of normal torque input based on the magnitude of the slip torque Tsb (total of Tsb1 and Tsb2) (absolute value). The external force is applied to the pulley structure 1 so that the friction torque TBb (absolute value), in which the torque (absolute value) decreases as the value) increases, is maintained at a level higher than the slip torque Tsb (set value). The magnitude of the resultant force (Fb1 + Fb2) between the pressure contact force Fb1 and the pressure contact force Fb2 (see FIG. 4A) and the springs 4 and 5 in a state where the pressure contact force Fb1 is not applied (when the pulley structure 1 is stopped). The following design items are appropriately determined.

(Spring 4 alone)
Assuming that the pressure contact force of the front end side region B1 of the spring 4 with respect to the pressure contact surface b1 is Fb1, the target torque curve (see FIG. 5), particularly the slip torque Tsb1 (absolute value), is large in the diameter expansion direction of the spring 4. Based on this, the friction torque TB1b1 (absolute value) at which the torque (absolute value) decreases as the torsion angle (absolute value) of the spring 4 increases at the time of normal torque input is higher than the slip torque Tsb1 (set value). The magnitude of the pressure contact force Fb1 (see FIG. 4A) in a state where no external force is applied to the pulley structure 1 (when the pulley structure 1 is stopped) so that the torque is maintained at a large level. , The radial and axial lengths of the pressure contact surface b1 (clutch engaging portion b1), the number of turns of the spring 4 (front end side region B1), and the like are appropriately determined.

(Spring 5 alone)
Assuming that the pressure contact force of the front end side region B2 of the spring 5 with respect to the pressure contact surface b2 is Fb2, the magnitude of the target torque curve (FIG. 5), particularly the slip torque Tsb2 (absolute value) in the diameter expansion direction of the spring 5. Based on the above, the friction torque TB2b2 (absolute value), in which the torque (absolute value) decreases as the torsion angle (absolute value) of the spring 5 increases at the time of normal torque input, is higher than the slip torque Tsb2 (set value). The magnitude of the pressure contact force Fb2 (see FIG. 4A) in a state where no external force is applied to the pulley structure 1 (when the pulley structure 1 is stopped) so as to maintain a large level, that is, Design items such as the radial and axial lengths of the pressure contact surface b2 and the number of turns of the spring 5 (front end side region B2) are appropriately determined.

For example, in this embodiment, it is designed as follows (Example 1 described later).
・ Slip torque Tsb (set value) in the diameter expansion direction: 30 N ・ m
* Equal to the sum of Tsb1 (below) and Tsb2 (below).
* It was set to the same level as the torsional torque when the lock mechanism operates in the conventional torque curve 2 (see FIG. 7).
* The allowable torque Tm1 (FIG. 5) was set to 25 N · m as in the conventional case 2 (Tm1 in FIG. 7).
・ Slip torque Tsb1 in the diameter expansion direction (set value): 22N ・ m
・ Slip torque Tsb2 in the diameter expansion direction (set value): 8N ・ m
Number of turns of the front end side region B1 of the spring 4: Within the range in which the torsional torque of the spring 4 does not reach the slip torque Tsb1 in the diameter expansion direction, the spring 4 (front end side region B1) and the pressure contact surface b1 (clutch engagement). The number of turns of the front end side region B1 is set to 2 (however, the frictionally engaged portion is 1.9 turns) so that the frictional engagement state can be maintained between the portion b1) and the B1b1. 2 rolls (however, the friction engagement part is 1.2 rolls).
Number of turns of the front end side region B2 of the spring 5: Within the range in which the torsional torque of the spring 5 does not reach the slip torque Tsb2 in the diameter expansion direction, the spring 5 (front end side region B2) and the pressure contact surface b2 (clutch engagement). The number of turns of the front end side region B2 is set to 2 turns (however, the friction engagement part is 1.9 turns) so that the frictional engagement between the portion b2) and the B2b2 can be maintained. ..
The radial length of the pressure contact surface b1 (clutch engaging portion b1) (outer diameter of the second groove bottom surface 3e (inner rotating body 3)): to the inner diameter 100 (index) of the spring 4 in a state where no external force is applied. On the other hand, it was set to 105. This level is a level that substantially coincides with the radial position (FIG. 10) of the middle region (free portion) of the coil spring when the lock mechanism of the conventional 2 is operated.
Axial length of the pressure contact surface b1 (clutch engaging portion b1): A length corresponding to the number of turns of the spring 4 (front end side region B1) in contact with the other.
The radial length of the pressure contact surface b2 (clutch engaging portion b2) (outer diameter of the cylinder body 3a (inner rotating body 3)): inner diameter 100 of the spring 5 (front end side region B2) in a state where no external force is applied. It was set to 106 with respect to (index).
Axial length of the pressure contact surface b2 (clutch engagement portion b2): A length corresponding to the number of turns of the spring 5 (front end side region B2) in contact with the other.

・ Comparison (comparison between the pressure contact surface a1 and the pressure contact surface b1 and the pressure contact surface b2)
The slip torque (Nm) (absolute value) is set to Tsa: 45> Tsb: 30.
The radial length (inner diameter of the outer rotating body 2) and the axial length of the pressure contact surface a1 (clutch engagement portion a1) are pressure contact with respect to the pressure contact surface a1 in a state where no external force is applied to the pulley structure 1. The resultant force (Fa1 + Fa2) of the force Fa1 (self-elastic restoring force in the diameter-expanding direction of the rear end side region A1) and the pressure contact force Fa2 (self-elastic restoring force in the diameter-expanding direction of the rear end side region A2) is the pressure contact surface. From the resultant force (Fb1 + Fb2) of the pressure contact force Fb1 with respect to b1 (self-elastic restoring force in the contraction direction of the front end side region B1) and the pressure contact force Fb2 with respect to the pressure contact surface b2 (self-elastic restoration force in the contraction direction of the front end side region B2). Is also set to be large (see FIG. 4 (a)).

Further, in a state where no external force is applied to the pulley structure 1, the self-elastic restoring force in the expansion direction in the rear end side region A1 of the spring 4 is the self in the contraction direction in the front end side region B1 of the spring 4. The self-elastic restoring force in the expansion direction in the rear end side region A2 of the spring 5 is larger than the elastic restoring force in the rear end side region A2 of the spring 5 in a state where no external force is applied to the pulley structure 1, which is larger than the elastic restoring force. It is configured to be larger than the self-elastic restoring force in the radial direction in the region B2.

(Structure of spring 4 and spring 5 in the axial direction)
The spring 4 is compressed in the axial direction in a state where no external force is applied to the pulley structure 1 (that is, a state in which the pulley structure 1 is stopped). The compressibility of the spring 4 in the axial direction may be, for example, about 20%. In the circumferential part of the axial end face of the front end side region B1 of the spring 4 (about 1/4 circumference (about 90 °) from the front end), a seat is used to stabilize the posture of the spring 4 compressed in the axial direction. The surface Be4 is formed (see FIG. 8). The counterbore surface Be4 is a plane formed by being subjected to grinding and orthogonal to the axial direction of the spring 4. Similarly, the posture of the spring 4 compressed in the axial direction is stabilized even in a part of the circumferential direction of the axial end surface of the rear end side region A1 of the spring 4 (about 1/4 circumference (about 90 °) from the rear end). Ae4 (not shown) is formed on the counterbore surface. Then, the countersunk surface Be4 of the spring 4 is in contact with the first groove bottom surface 3d of the inner rotating body 3, and the counterbore surface Ae4 of the spring 4 is in contact with the thrust plate 10 (see FIG. 1).

The spring 5 is compressed in the axial direction in a state where no external force is applied to the pulley structure 1 (that is, a state in which the pulley structure 1 is stopped). The compressibility of the spring 5 in the axial direction may be, for example, about 20%. In the circumferential part of the axial end face of the front end side region B2 of the spring 5 (about 1/4 circumference (about 90 °) from the front end), a seat is used to stabilize the posture of the spring 5 compressed in the axial direction. A ground surface Be5 is formed (see FIG. 8). The counterbore surface Be5 is a plane formed by being subjected to grinding and orthogonal to the axial direction of the spring 5. Similarly, the posture of the spring 5 compressed in the axial direction is stabilized even in a part of the circumferential direction of the axial end surface of the rear end side region A2 of the spring 5 (about 1/4 circumference (about 90 °) from the rear end). Ae5 (not shown) is formed on the counterbore surface. Then, the countersunk surface Be5 of the spring 5 is in contact with the second groove bottom surface 3e of the inner rotating body 3, and the counterbore surface Ae5 of the spring 5 is in contact with the thrust plate 10 (see FIG. 1).

(Middle region of spring 4 and spring 5)
As shown in FIG. 1, the middle region C1 of the spring 4 is a region (middle region) between the front end side region B1 and the rear end side region A1 of the spring 4, and is either the pressure contact surface b1 or the pressure contact surface a1. It is a free part that does not come into contact with. The number of turns of the middle region C1 (free portion) of the spring 4 is the target spring constant of the spring 4 (the ratio of the torsional torque to the torsional angle of the spring 4, that is, the inclination of the torque curve) and the torsional angle of the spring 4. It is appropriately set based on the permissible range (for example, 60 ° in both the diameter expansion direction and the diameter reduction direction).

As shown in FIG. 1, the middle region C2 of the spring 5 is a region (middle region) between the front end side region B2 and the rear end side region A2 of the spring 5, and is either the pressure contact surface b2 or the pressure contact surface a2. It is a free part that does not come into contact with. The number of turns of the middle region C2 (free portion) of the spring 5 is the target spring constant of the spring 5 (the ratio of the torsional torque to the torsional angle of the spring 5, that is, the inclination of the torque curve) and the torsional angle of the spring 5. It is appropriately set based on the permissible range (for example, 60 ° in both the diameter expansion direction and the diameter reduction direction).

For example, in this embodiment, it is designed as follows (Example 1 described later).
-Number of turns of the middle region C1 (free part) of the spring 4: 4 turns (same as the conventional 2; the conventional 1 has 3 turns)
-Effective number of turns of the spring 4 when the diameter is expanded and deformed: 4 turns (does not increase with respect to the number of turns of the middle region C1)
In addition, the conventional 1 has 3 turns + α (the effective number of turns increases as the front end side region of the spring separates from the inner rotating body).
-Allowable range of torsion angle of spring 4: ± 60 °
-Number of turns of the middle region C2 (free part) of the spring 5: 4 turns-Effective number of turns of the spring 5 during diameter expansion deformation: 4 turns (does not increase with respect to the number of turns of the middle region C2)
-Allowable range of torsion angle of spring 5: ± 60 °

(Contrast with conventional (spring constant))
The spring constant k1 (inclination of the torque curve in FIG. 5) of the entire spring is the same as the spring constant k1 (FIG. 7) of the conventional 2 pulley structure designed as an ISG-compatible pulley, and its level is not ISG-compatible. The spring constant k0 (between θ1 and θ2) of the conventional pulley structure 1 which is a pulley is set to be significantly larger than that (FIG. 6).
The number of turns of each of the middle region C1 of the spring 4 and the middle region C2 of the spring 5 is conventionally (in the conventional 2) the torsion angle in the expansion direction in which the locking mechanism works within the allowable torsion angle range (± 60 °). Θ2 in FIG. 7: about 35 °) and the same level as the torsional torque (about 30 Nm), the clutch operates (the torsional torque of the entire spring reaches the slip torque Tsb, and B1b1 and B2b2 slide between B1b1 and B2b2. ), And within the allowable range of torsion angle (± 60 °), it is the same as the torsion angle in the reduced diameter direction (-θ3: about -55 ° in FIG. 7) and the torsion torque (about -45 Nm). At the level, the clutch is properly set so that it can operate (the torsional torque of the entire spring reaches the slip torque Tsa and slides between A1a1).

(The lock mechanism does not work)
In the pulley structure 1 of the present embodiment, the clutch (spring 4 and spring 5) engaged with the clutch engaging portion is disengaged in both directions (in the direction of expansion or contraction of the spring 4 and the spring 5). The lock mechanism is configured not to operate until the state is reached (FIGS. 4 (b) and 4 (c)).
Specifically, while the torsional torque of the spring 4 does not reach the slip torque set in both directions (in the direction of expansion or contraction of the spring 4), the middle region C1 (free portion) of the spring 4 rotates outward. In a state where no external force is applied to the pulley structure 1 so as not to come into contact with either the body 2 or the spring 5, the middle region C1 of the spring 4 and the middle region C1 of the spring 4 and the outer rotating body 2 are not contacted. The size (clearance) of the gap between the spring 5 and the spring 5 is sufficiently wide (see FIGS. 1 and 4 (a)). Similarly, while the torsional torque of the spring 5 does not reach the slip torque set in both directions (in the direction of expansion or contraction of the spring 5), the middle region C2 (free portion) of the spring 5 is the spring 4 and the cylinder. In a state where no external force is applied to the pulley structure 1 so as not to contact any of the main body 3a, between the middle region C2 of the spring 5 and the spring 4, and the middle region C2 of the spring 5 and the cylinder main body 3a ( The size (clearance) of the gap between the inner rotating body 3) is sufficiently wide (see FIGS. 1 and 4 (a)).

(Comparison with conventional: When spring 4 and spring 5 are twisted in the diameter expansion direction)
When the pulley structure 1 is stopped, the gap between the middle region C1 of the spring 4 and the outer rotating body 2 is wider than that of the conventional 2. Therefore, even at the twist angle (θ2: about 35 °) at which the lock mechanism operates in the conventional 2, the middle region C1 of the spring 4 does not come into contact with the annular surface 2b (outer rotating body 2) (that is, the lock mechanism does not operate). ) (See Fig. 4 (b)).

Further, the gap between the middle region C2 of the spring 5 and the spring 4 (particularly, the rear end side region A1) when the pulley structure 1 is stopped is sufficiently wide. Therefore, even at the torsional angle (θ2: about 35 °) at which the lock mechanism operates in the conventional 2, the middle region C2 of the spring 5 does not come into contact with the spring 4 (that is, the lock mechanism does not operate) (that is, the lock mechanism does not operate). See FIG. 4 (b)).

(Comparison with conventional: When spring 4 and spring 5 are twisted in the radial direction)
The gap between the middle region C1 of the spring 4 and the spring 5 (particularly, the front end side region B2) when the pulley structure 1 is stopped is sufficiently wide. Therefore, when the spring 4 is twisted in the contraction direction, the middle region C1 of the spring 4 does not come into contact with the spring 5 even at the twist angle in the contraction direction (−θ3: about −55 °) as in the conventional case 2. (That is, the lock mechanism does not operate) (see FIG. 4 (c)).

Further, the gap between the middle region C2 of the spring 5 and the cylinder body 3a (inner rotating body 3) when the pulley structure 1 is stopped is sufficiently wide. Therefore, when the spring 5 is twisted in the diameter reduction direction, the middle region C2 of the spring 5 is the cylinder body 3a (inside) even at the twist angle in the diameter reduction direction (−θ3: about −55 °) as in the conventional case 2. It is designed so that it does not come into contact with the rotating body 3) (that is, the locking mechanism does not operate) (see FIG. 4 (c)).

(Operation of pulley structure 1)
Next, the operation of the pulley structure 1 will be described.

(I When the outer rotating body accelerates)
When the outer rotating body 2 rotates relative to the inner rotating body 3 in the positive direction (clockwise from the front end to the rear end: see FIGS. 2 and 3) (when the outer rotating body 2 accelerates), the spring 4 And since the winding direction of the spring 5 is left-handed (counterclockwise from the front end to the rear end), the rear end side region A1 of the spring 4 and the rear end side region of the spring 5 are accompanied by the relative rotation of the outer rotating body 2. A2 moves together with the pressure contact surface a1 of the outer rotating body 2 and rotates relative to the inner rotating body 3. As a result, the spring 4 and the spring 5 are expanded and deformed. This is because in the ISG system, when the pulley structure 1 (pulley for ISG) operates as a driven pulley (for example, after the initial explosion at the time of starting the engine by ISG, during power generation by ISG, etc., while the outer rotating body 2 accelerates. ).

(At the time of normal torque input to the I-I outer rotating body)
The pressure contact force Fa1 between the rear end side region A1 of the spring 4 and the pressure contact surface a1 (clutch engaging portion a1) (inner peripheral surface of the outer rotating body 2) (between A1a1) is a torsion in the expansion direction of the spring 4. The increase increases as the angle increases, but since the inner peripheral surface of the outer rotating body 2 that becomes the pressure contact surface a1 (clutch engaging portion a1) is an inner peripheral wall surface that is closed in the circumferential direction, the spring 4 (rear end side region). A1) is immediately in a state of being strongly frictionally engaged with the outer rotating body 2 (a locked state between A1a1) (with almost no relative sliding of the pressure contact surface a1) (see FIG. 4B). ..

Similarly, the pressure contact force Fa2 between the rear end side region A2 of the spring 5 and the pressure contact surface a2 (inner peripheral surface of the rear end side region A1 of the spring 4) (between A2a2) is a torsion in the expansion direction of the spring 5. The increase increases as the angle increases, but the spring 4 (rear end side region A1), which is the pressure contact surface a2, is in a state of being strongly frictionally engaged with the outer rotating body 2 (locked state between A1a1). 5 (rear end side region A2) is immediately in a state of being strongly frictionally engaged with the spring 4 (locked state between A2a2) (with almost no relative sliding of the pressure contact surface a2) (FIG. 4 (FIG. 4). b) See).

On the other hand, the pressure contact force Fb1 between the front end side region B1 of the spring 4 and the pressure contact surface b1 (clutch engaging portion b1) (outer peripheral surface of the cylinder body 3a) (between B1b1) is a torsion angle in the diameter expansion direction of the spring 4. As the value increases, the torque decreases and the friction torque between B1b1 (TB1b1) decreases (see FIGS. 4 (b) and 5).

During this period, the torsional torque (transmission torque) (absolute value) of the spring 4 increases as the torsional angle of the spring 4 in the diameter expansion direction increases (see FIG. 5). Therefore, while the torsional torque of the spring 4 does not reach the set slip torque Tsb1 (for example, 22 Nm) (see FIG. 5), the spring 4 is inserted between the outer rotating body 2 and the inner rotating body 3. The torque is transmitted, and the spring 4 is twisted in the circumferential direction according to the spring constant (inclination of the torque curve) of the spring 4, so that the tension fluctuation of the belt is appropriately suppressed.

Similarly, the pressure contact force Fb2 between the front end side region B2 of the spring 5 and the pressure contact surface b2 (clutch engaging portion b2) (outer peripheral surface of the cylinder body 3a) (between B2b2) is a torsion in the diameter expansion direction of the spring 5. As the angle becomes larger, the torque decreases, and the friction torque between B2b2 (TB2b2) decreases (see FIGS. 4 (b) and 5).

During this period, the torsional torque (transmission torque) (absolute value) of the spring 5 increases as the torsional angle of the spring 5 in the diameter expansion direction increases (see FIG. 5). Therefore, while the torsional torque of the spring 5 does not reach the set slip torque Tsb2 (for example, 8 Nm) (see FIG. 5), the spring 5 is inserted between the outer rotating body 2 and the inner rotating body 3. The torque is transmitted and the spring 5 is twisted in the circumferential direction according to the spring constant (inclination of the torque curve) of the spring 5, so that the tension fluctuation of the belt is appropriately suppressed.

Therefore, among the driving patterns by ISG in the ISG system, for example, even during power generation by ISG, if the input torque level at that time is less than the set slip torque (Tsb) in the expansion direction (for example). If the slip torque Tsb level is set to about 30 Nm for the input torque level of 15 to 25 Nm), it can be operated as an ISG pulley without any problem, and the tension fluctuation of the belt is appropriate. It can be suppressed.

(When excessive torque is input to the I-II outer rotating body (when the outer rotating body suddenly accelerates))
When the torsion angle of the spring 4 in the expansion direction becomes larger, the torsion torque of the spring 4 reaches the set slip torque (Tsb1) (for example, 22 Nm), and the friction torque TB1b1 between B1b1 is decreasing. However, when the slip torque Tsb1 is reached (see FIG. 5), the spring 4 and the inner rotating body 3 slide (slip) between B1b1 (the engagement is disengaged) (see FIG. 4 (b)). ).

It should be noted that the lock mechanism is configured not to operate until the clutch (spring 4) is in the disengaged state on the clutch engaging surface (see FIG. 4 (b)).

Similarly, when the torsion angle of the spring 5 in the expansion direction becomes larger, the torsion torque of the spring 5 reaches the set slip torque (Tsb2) (for example, 8 Nm) and is decreasing between B2b2. When the friction torque TB2b2 reaches the slip torque Tsb2 (see FIG. 5), the spring 5 and the inner rotating body 3 slide (slip) between the B2b2 (the engagement is disengaged) (FIG. 4 (FIG. 5). b) See).

(II When the outer rotating body slows down)
When the outer rotating body 2 rotates relative to the inner rotating body 3 in the opposite direction (counterclockwise from the other end to one end) (when the outer rotating body 2 decelerates or the inner rotating body 3 accelerates). Case), with the relative rotation of the outer rotating body 2, the rear end side region A1 of the spring 4 and the rear end side region A2 of the spring 5 move together with the pressure contact surface a1 of the outer rotating body 2 and move to the inner rotating body 3. It rotates relative to it. As a result, the spring 4 and the spring 5 are deformed in diameter. Here, the case where the internal rotating body 3 accelerates means that the pulley structure 1 (the pulley for ISG) operates as a drive pulley in the ISG system (for example, before the first explosion at the time of starting the engine by ISG, assist by ISG). It corresponds to (when driving, etc.).

(At the time of normal torque input to the II-I outer rotating body)
The pressure contact force Fa1 between the rear end side region A1 of the spring 4 and the pressure contact surface a1 (clutch engaging portion a1) (inner peripheral surface of the outer rotating body 2) (between A1a1) is a torsion in the radial direction of the spring 4. As the angle becomes larger, the torque decreases, and the friction torque between A1a1 (TA1a1) decreases (see FIGS. 4 (c) and 5).

Similarly, the pressure contact force Fa2 between the rear end side region A2 of the spring 5 and the pressure contact surface a2 (inner peripheral surface of the spring 4) (between A2a2) also decreases as the torsion angle in the contraction direction of the spring 5 increases. , The friction torque between A2a2 (TA2a2) is reduced (see FIG. 4C and FIG. 5).

Therefore, the pressure contact force (Fa1 + Fa2) with respect to the pressure contact surface a1 of the entire spring decreases as the torsion angle in the radial direction of the spring 4 and the spring 5 increases, and the friction torque (TAa) between the entire spring and the pressure contact surface a1. (See FIG. 4 (c), FIG. 5).

On the other hand, the pressure contact force Fb1 between the front end side region B1 of the spring 4 and the pressure contact surface b1 (clutch engaging portion b1) (outer peripheral surface of the inner rotating body 3) (between B1b1) is twisted in the contraction direction of the spring 4. Although it increases as the angle increases, the spring 4 (front end side region B1) is formed because the outer peripheral surface of the inner rotating body 3 which is the pressure contact surface b1 (clutch engaging portion b1) is an outer peripheral wall surface closed in the circumferential direction. Immediately (with almost no relative sliding of the pressure contact surface b1), the inner rotating body 3 is strongly frictionally engaged (locked between B1b1) (see FIG. 4C).

During this period, the torsional torque (transmission torque) (absolute value) of the spring 4 increases as the torsional angle of the spring 4 in the contraction direction increases (see FIG. 5). Therefore, while the torsional torque of the spring 4 does not reach the set slip torque Tsa1 (for example, −33 Nm) (see FIG. 5), the spring 4 is inserted between the outer rotating body 2 and the inner rotating body 3. Torque is transmitted through the spring 4, and the spring 4 is twisted in the circumferential direction according to the spring constant (inclination of the torque curve) of the spring 4, so that the tension fluctuation of the belt is appropriately suppressed.

Similarly, the pressure contact force Fb2 between the front end side region B2 of the spring 5 and the pressure contact surface b2 (clutch engaging portion b2) (outer peripheral surface of the inner rotating body 3) (between B2b2) is the pressure contact force Fb2 in the contraction direction of the spring 5. The larger the twist angle, the larger the increase. However, since the outer peripheral surface of the inner rotating body 3 serving as the pressure contact surface b2 (clutch engaging portion b2) is the outer peripheral wall surface closed in the circumferential direction, the spring 5 (front end side region B2). Immediately (with almost no relative sliding of the pressure contact surface b2), is strongly frictionally engaged with the inner rotating body 3 (locked state between B2b2) (see FIG. 4C).

During this period, the torsional torque (transmission torque) (absolute value) of the spring 5 increases as the torsional angle of the spring 5 in the contraction direction increases (see FIG. 5). Therefore, while the torsional torque of the spring 5 does not reach the set slip torque Tsa2 (for example, -12 Nm) (see FIG. 5), the spring 5 and the inner rotating body 3 are placed between the outer rotating body 2 and the inner rotating body 3. Torque is transmitted via the spring 4, and the spring 5 is twisted in the circumferential direction according to the spring constant (inclination of the torque curve) of the spring 5, so that the tension fluctuation of the belt is appropriately suppressed.

Therefore, among the driving patterns by ISG in the ISG system, for example, even during assisted driving by ISG, the slip torque (Tsa) in the contraction direction in which the input torque level (absolute value) at that time is set is set. If it is less than the standard (absolute value) (for example, if the slip torque Tsa is set to about -45 Nm for the input torque level of -35 to -30 Nm), it operates as an ISG pulley without any problem. The torque fluctuation of the belt can be appropriately suppressed.

(When excessive torque is input to the II-II outer rotating body (during sudden deceleration of the outer rotating body))
Further, when the torsion angle of the entire spring of the spring 4 and the spring 5 in the contraction direction becomes large, the torsion torque of the entire spring reaches the set slip torque Tsa (for example, -45 Nm) and is decreasing. When the friction torque (TAa) (absolute value) between the entire spring and the pressure contact surface a1 reaches the slip torque Tsa (absolute value) (see FIG. 5), the outer rotation occurs between the entire spring and the pressure contact surface a1. The body 2 and the inner rotating body 3 and the entire spring slide (slip) (become in the disengaged state) (see FIG. 4 (c)). When the clutch operates on the pressure contact surface a1 (clutch engagement portion a1), that is, when the outer peripheral surface of the spring 4 (rear end side region A1) is sliding with respect to the pressure contact surface a1, the spring 5 The outer peripheral surface of (rear end side region A2) is slid with respect to the pressure contact surface a1 via the spring 4 (rear end side region A1), and the spring 4 (rear end side region A1) is slid. ) Does not slide (relative rotation does not occur).

In the clutch engaging portion, the lock mechanism is configured not to operate until the clutch (spring 4 and spring 5) is in the disengaged state.

According to the above configuration, the two coil springs of the spring 4 and the spring 5 are used, and the spring 5 is arranged side by side in the radial direction of the spring 4, so that the spring wire in the spring 4 is arranged in parallel. The size of the cross section that passes through the rotation axis of the outer rotating body 2 and along the direction parallel to the rotation axis can be made smaller than that of the conventional 2. Further, the cross-sectional area of the spring wire in the spring 5 is significantly smaller than that of the spring 4 because the inner diameter is smaller than that of the spring 4 (the smaller the inner diameter than the spring 4, the larger the spring constant is). In order to provide the spring constant of the spring 5 at a low level, the spring 5 can be formed so that the cross-sectional area of the spring wire is significantly smaller than that of the spring 4).
Therefore, according to the above configuration, it is possible to prevent the pulley structure 1 from becoming larger in the direction of the rotation axis (effect 1).

Further, in both directions (diameter expansion or contraction direction of the two coil springs of the spring 4 and the spring 5), the respective ends of the spring 4 and the spring 5 are in pressure contact with the outer rotating body 2 or the inner rotating body 3. The direction of the force (diameter direction) can be reversed (bias relationship) between the rear end side (one end side) and the front end side (the other end side).
Therefore, in both directions, the frictional engagement state between the two coil springs of the spring 4 and the spring 5 and the outer rotating body 2 and the inner rotating body 3 (the pressure contact state of the two coil springs) is the two coil springs. As the twist angle (absolute value) of is larger, the following states (a) and (b) are obtained. (A) The outer peripheral surface of the rear end side region A1 has an increased pressure contact force (Fa1 + Fa2) with respect to the outer rotating body 2 and is strongly frictionally engaged with the outer rotating body 2. (b) The inner rotating body 3 of the front end side region B1. The pressure contact force Fb1 with respect to the inner rotating body 3 and the pressure contact force Fb2 with respect to the inner rotating body 3 of the front end side region B2 decrease, and the inner rotating body 3 starts to slide (disengage).
Alternatively, (a) the pressure contact force Fb1 with respect to the inner rotating body 3 of the front end side region B1 and the pressure contact force Fb2 with respect to the inner rotating body 3 of the front end side region B2 increase and strongly frictionally engage with the inner rotating body 3 (b). On the outer peripheral surface of the rear end side region A1, the pressure contact force (Fa1 + Fa2) with respect to the outer rotating body 2 decreases, and the outer peripheral surface begins to slide (disengage) with respect to the outer rotating body 2.
That is, each end of the two coil springs brings about the opposite action (above (a) and (b)).
As a result, (i) when the normal torque (torsional torque of the two coil springs within the range that does not reach the set slip torque) is input, the two coil springs are torsionally deformed in both directions (diameter expansion or contraction direction). At that time, the torque is transmitted between the outer rotating body 2 and the inner rotating body 3 by engaging with the outer rotating body 2 and the inner rotating body 3.
On the other hand, (ii) when an excessive torque (twisting torque of two coil springs equal to or higher than the set slip torque) is input, the two coil springs are connected to the outer rotating body 2 in both directions (diameter expansion or contraction direction). When a predetermined torque or more is transmitted between the inner rotating body 3 and the outer rotating body 2, the outer rotating body 2 or the inner rotating body 3 is in an disengaged state of sliding with the outer rotating body 2 or the inner rotating body 3. Cut off the transmission of torque between.
As a result, for example, at the time of cold start of the engine by ISG, even if an excessive torque (for example, a torque of slip torque of 30 Nm or more in the diameter expansion direction) is input to the outer rotating body 2, the outer rotating body 2 starts. No impact load (excessive rotational braking force) acts on the belt (tension side) on the torque input side, and it is possible to suppress an excessive increase in belt tension and an excessive fluctuation in belt tension.
On the contrary, even if the engine is unexpectedly stopped (stall) due to derailment while the engine is running (for example, even if a slip torque of 45 Nm or more is input in the diameter reduction direction), the belt tension ( The tension side) does not drop excessively, and it is possible to prevent the belt from slipping.
As a result, as shown in (i) and (ii) above, the coil spring type clutch function (torque transmission or disconnection) can be secured in both directions (diameter expansion direction and diameter reduction direction of the two coil springs). (Effect 2).

Further, the spring 4 has a middle region C1 which is a free portion that does not come into contact with either the outer rotating body 2 or the spring 5 when the outer rotating body 2 and the inner rotating body 3 rotate relative to each other. It has a middle region C2 which is a free portion that does not come into contact with either the spring 4 or the inner rotating body 3 when the outer rotating body 2 and the inner rotating body 3 rotate relative to each other. This makes it possible to reliably prevent the lock mechanism from operating in both directions (in the direction of expansion or contraction of the two coil springs of the spring 4 and the spring 5). As a result, for example, even if an excessive torque is input to the outer rotating body 2, the two coil springs (clutches) of the spring 4 and the spring 5 are strongly frictionally engaged with the outer rotating body 2 or the inner rotating body 3 (for example, It is possible to prevent the vehicle from falling into a locked state (effect 3).

Further, in a state where no external force is applied to the pulley structure 1, the self-elastic restoring force in the expansion direction in the rear end side region A1 of the spring 4 is the self in the contraction direction in the front end side region B1 of the spring 4. The self-elastic restoring force in the expansion direction in the rear end side region A2 of the spring 5 is larger than the elastic restoring force in the rear end side region A2 of the spring 5 in a state where no external force is applied to the pulley structure 1, which is larger than the elastic restoring force. It is configured to be larger than the self-elastic restoring force in the radial direction in the region B2.
Therefore, the torque (slip torque Tsa1, Tsa2) (absolute value) at which the clutch operates when the spring 4 and the spring 5 are twisted in the radial direction is twisted in the radial direction of the spring 4 and the spring 5. In this case, it is possible to ensure that the torque (slip torque Tsb1, Tsb2) (absolute value) at which the clutch operates is set to be larger than the torque (slip torque Tsb1, Tsb2) (absolute value).
As a result, the pulley structure 1 is replaced with an ISG pulley (when the pulley structure 1 is a drive pulley (for example, during cranking before the initial explosion at the time of starting the engine by ISG, during assisted running by ISG), and a driven pulley (when the pulley structure 1 is assisted by ISG). For example, by applying it to the ISG system as (playing both roles (after the first explosion at the time of engine start by ISG) and at the time of power generation by ISG), in each running pattern at the time of engine start, assisted running, and power generation. It can be suitably dealt with (effect 4).

(Other embodiments)
In the above-described embodiment, in a state where no external force is applied to the pulley structure 1, the outer peripheral surface of the one end side region (rear end side region A1) of the spring 4 rotates outward due to the self-elastic restoring force in the expansion direction. The outer peripheral surface of the one end side region (rear end side region A2) of the spring 5 is in contact with the pressure contact surface a1 (clutch engagement portion a1) of the body 2 due to the self-elastic restoring force in the expansion direction of the spring 4. The inner peripheral surface of the other end side region (front end side region B1) of the spring 4 comes into contact with the one end side region (rear end side region A1), and the pressure contact surface in the inner rotating body 3 due to the self-elastic restoring force in the radial direction. The inner peripheral surface of the other end side region (front end side region B2) of the spring 5 is in contact with b1 (clutch engaging portion b1), and the pressure contact surface in the inner rotating body 3 is due to the self-elastic restoring force in the radial direction. Although it was in contact with b2 (clutch engaging portion b2) (* corresponding to Patent Document 1, First Embodiment FIG. 1), the present invention is not limited to this. That is, in a state where no external force is applied to the pulley structure, the outer peripheral surface of the one end side region (in this case, the front end side region B1) of the first coil spring rotates inward due to the self-elastic restoring force in the expansion direction. The outer peripheral surface of the one end side region (in this case, the front end side region B2) of the second coil spring is in contact with the pressure contact surface (clutch engagement portion) of the body due to the self-elastic restoring force in the expansion direction. The inner peripheral surface of the other end side region (in this case, the rear end side region A1) of the first coil spring comes into contact with the one end side region (in this case, the front end side region B1) of the coil spring of No. 1 in the radial direction. Due to the self-elastic restoring force of, the inner peripheral surface of the other end side region (in this case, the rear end side region A2) of the second coil spring is in contact with the pressure contact surface (clutch engagement portion) of the outer rotating body. , The self-elastic restoring force in the radial direction may be in contact with the pressure contact surface (clutch engaging portion) of the outer rotating body (corresponding to Patent Document 1 Second Embodiment FIG. 5).

Further, in the above-described embodiment, the winding direction of the spring 4 and the winding direction of the spring 5 are left-handed (counterclockwise from the front end to the rear end), but the winding direction of the spring 4 and the winding direction of the spring 5 are right. It may be wound (clockwise from the front end to the rear end). In this case, in a state where no external force is applied to the pulley structure, the outer peripheral surface of the one end side region (in this case, the front end side region B1 in this case) of the first coil spring is outward due to the self-elastic restoring force in the expansion direction. The outer peripheral surface of the one end side region (in this case, the front end side region B2) of the second coil spring is in contact with the pressure contact surface (clutch engagement portion) of the rotating body due to the self-elastic restoring force in the expansion direction. The inner peripheral surface of the one end side region (in this case, the front end side region B1 in this case) of the first coil spring is in contact with the other end side region (in this case, the rear end side region A1) of the first coil spring. Due to the self-elastic restoring force in the direction, it comes into contact with the pressure contact surface (clutch engaging portion) of the inner rotating body, and the inner peripheral surface of the other end side region (in this case, the rear end side region A2) of the second coil spring. However, due to the self-elastic restoring force in the radial direction, it comes into contact with the pressure contact surface (clutch engaging portion) of the inner rotating body (corresponding to Patent Document 1, Fourth Embodiment FIG. 11).

Next, the pulley structure 1 (FIG. 1) of the above embodiment is taken as Example 1, the pulley structure of the conventional 2 (FIG. 10) is taken as Comparative Example 1, and each pulley structure is used as a belt system shown in FIG. It was installed and an engine cold start test was conducted by ISG (hereinafter, simply "engine cold start test"). In this cold engine start test, the following evaluation items at the time of cold engine start were detected and recorded in chronological order, and the effect of the present invention was verified by comparing Example 1 and Comparative Example 1.

(Sample: Pulley structure of Example 1)
The first embodiment corresponds to the pulley structure 1 according to the above embodiment.
At the time of cold engine start, the clutch is configured to operate between B1b1 and B2b2 when the outer rotating body 2 suddenly accelerates and the spring 4 and the spring 5 are twisted in the diameter expansion direction.

(Comparison with Comparative Example 1 (common points))
The configuration in which the clutch operates between A1a1 when the entire spring is twisted in the radial direction, and the level of its torque (slip torque Tsa) are the same as in Comparative Example 1 (conventional 2).
Therefore, it was presumed that the magnitude of the dynamic belt minimum tension at the time of the first in-cylinder explosion at the time of cold engine start) is substantially the same as that of Comparative Example 1.

(Spring 4 and Spring 5 of Example 1 (FIGS. 1 and 8))
-The spring wires of the springs 4 and 5 are spring oil tempered wires (based on JISG3560: 1994).
The number of turns N of the spring 4 and the spring 5 was set to 9, and the winding direction was set to left-handed.
The axial compression ratio of the spring 4 and the spring 5 was set to about 20%. The gap between the spring wires adjacent to each other in the axial direction was set to 0.3 mm in a state where the spring 4 and the spring 5 were compressed in the axial direction.
The spring wire of the spring 4 has a rectangular shape, the axial length is 4.4 mm, and the radial length is 6.0 mm. The four corners in the cross section of the spring wire have a chamfered shape (R surface having a radius of curvature of about 0.3 mm).
The spring wire of the spring 5 has a rectangular shape, the axial length is 3.4 mm, and the radial length is 3.4 mm. The four corners in the cross section of the spring wire have a chamfered shape (R surface having a radius of curvature of about 0.3 mm).
The axial length of the outer rotating body 2 was about 90 (index) when Comparative Example 1 (conventional 2) was set to 100 (index).

(Test piece: Pulley structure of Comparative Example 1)
Comparative Example 1 corresponds to the above-mentioned conventional 2 pulley structure (see FIG. 10).
At the time of cold engine start, the lock mechanism is configured to operate when the outer rotating body suddenly accelerates and the spring twists in the diameter expansion direction.

(Coil spring of Comparative Example 1 (FIG. 10))
The number of turns N of the spring is 9, the spring wire is trapezoidal, and the cross-sectional area thereof is about 1.3 times that of the first embodiment (about twice that of the conventional one). The configuration of each of the other parts of Comparative Example 1 is the configuration described in the above-mentioned (this embodiment) contrasting portion with the conventional one.

(Summary of Example 1 and Comparative Example 1)

(Engine cold start test)
Each of the pulley structures of Example 1 and Comparative Example 1 was subjected to an engine cold start test using the engine bench tester 200 shown in FIGS. 11 and 12. In this engine cold start test, an excessive torque is input to the outer rotating body of the pulley structure via the belt, the spring twists in the diameter expansion direction, and in the case of the first embodiment, the clutch (between B1b1 and B2b2). In the case of Comparative Example 1, it is an actual tabletop test that can maximize the rotation fluctuation of the engine so that the lock mechanism can be operated reliably. Here, the cold engine start is a form of engine start, and specifically, the engine is in a state where the engine is completely cooled (for example, the temperature of the engine cooling water is 30 ° C. or less). Refers to the start. Therefore, starting the engine from a state in which the engine is temporarily stopped (idle stop, etc.) during running (after the completion of warming up) is excluded from this test condition.

The engine bench tester 200 is a test device including an auxiliary drive system, and is a crank pulley 201 attached to the crank shaft 211 of the engine 210, an AC pulley 202 connected to an air conditioner compressor (AC), and a water pump. It has a WP pulley 203 connected to (WP). Each of the pulley structures of Example 1 and Comparative Example 1 (pulley structure 100 in FIGS. 11 and 12) is connected to the shaft 221 of the motor generator (ISG) 220. Further, an auto tensioner (A / T) 204 is provided between the belt spans of the crank pulley 201 and the pulley structure 100. The output of the engine is transmitted clockwise from the crank pulley 201 to the pulley structure 100, the WP pulley 203, and the AC pulley 202 via one belt (V-ribbed belt) 250, and each auxiliary machine ( Motor generators (ISGs), water pumps, air conditioners and compressors) are driven.

Further, as shown in FIG. 12, a touch pulley 205 having a sensor (strain gauge) (not shown) for dynamic belt tension measurement attached on the mounting shaft is temporarily installed between the tension side belt spans on the belt system. ing. The sensor (strain gauge) is connected to a PC (personal computer) via a bridge box, a strain amplifier, and a data logger (not shown). By doing so, the belt tension (dynamic belt tension, hereinafter simply referred to as belt tension) during running of the belt 250 can be continuously measured, and the dynamic belt maximum tension (maximum value of dynamic belt tension) (N). / Belt) can be read from the data of the time-series change of the dynamic belt tension.

(Evaluation item)
The time-series change (output) of the belt tension (dynamic belt tension) (tension side) at the time of cold engine start (when the engine is started when the engine is completely cold) was evaluated.

(conditions)
Cold start (cranking) of the engine is performed at an atmospheric temperature of about 0 ° C (a test machine is installed in a low temperature room to start the engine when the engine is completely cold) and a belt tension (at the time of installation) of 1200N. rice field. When the engine was started by ISG, the level of torque input to the inner rotating body of the pulley structure 100 (ISG pulley) was about -30 Nm.

(Engine starting operation)
An engine start signal is sent from the electronic control device (not shown) to the motor generator (ISG) (not shown), the motor generator (ISG) is started, and cranking is started. At this time (before the combustion explosion in each cylinder), the rotation speed of the crank shaft 211 is about 200 rpm.
A fuel injection signal and an ignition signal are sent from the electronic control device to the fuel injection device (not shown) and the ignition device (not shown), and the combustion explosion in each cylinder is started in sequence.
The rotation speed of the crank shaft 211 increases in synchronization with the combustion explosion time in each cylinder. The rotational torque (power) of the crank shaft 211 is transmitted to the crank pulley 201 (outer ring), and further transmitted to the engine bench tester 200.
When the engine is started, the cranking operation by the motor generator (ISG) is stopped.

The pulley structures of Example 1 and Comparative Example 1 are configured so that the level of the slip torque Tsa is about -45 Nm while the level of the input torque at the time of starting the engine by ISG is about -30 Nm. ing. Therefore, the torque input to the inner rotating body can be transmitted to the outer rotating body via the spring (the spring is twisted in the radial direction by accelerating the inner rotating body) without any problem. That is, when the engine is started by ISG, it can be operated as an ISG pulley without any problem, and cranking can be performed while appropriately suppressing the tension fluctuation of the belt.

(Evaluation methods)
Based on the waveform data (graph) showing the time-series change of the belt tension at the time of cold engine start obtained by the engine cold start test by the above operation for each of the pulley structures of Example 1 and Comparative Example 1. Belt maximum tension (maximum belt tension) (N / belt), belt minimum in the waveform where the belt tension is the most excessively increased and the most excessively decreased (that is, the waveform at the time of the first in-cylinder explosion). After reading the tension (minimum value of belt tension) (N / belt) and the fluctuation range of belt tension (N / belt), the evaluation of Example 1 was performed based on the following evaluation criteria.

(Evaluation criteria: Evaluation of belt tension (excessive increase) and suppression of belt tension (excessive) fluctuation)
Difference amount (N / belt) between Example 1 and Comparative Example 1 regarding the magnitude of belt tension and belt tension fluctuation at the time of the first in-cylinder explosion (that is, the portion indicated by "m" in FIG. 13). To read. The ratio (percentage) (%) of this difference amount m (N / belt) to the dynamic belt maximum tension (N / belt) in Comparative Example 1 is the variation of the belt tension and the belt tension with respect to Comparative Example 1 of Example 1. Corresponds to the suppressive effect.
When the suppressing effect is 25% or more (significant), the evaluation is "○" because there is no possibility of impairing the durability of the belt system.
On the other hand, if the suppressing effect is less than 25%, the durability of the belt system may be impaired, and the evaluation is "x".

(Evaluation results)
FIG. 13 shows a graph showing the time-series change of the dynamic belt tension (simply, the belt tension) at the time of the engine cold start obtained by the engine cold start test. The evaluation results (list of test results) are shown in Table 5.

(Engine cold start test test result)

In FIG. 13, the portion indicated by “m” at the time of the first in-cylinder explosion (a in the figure) is the same as that of the first embodiment regarding the magnitude of the belt tension and the belt tension fluctuation at the time of the first in-cylinder explosion. This is a difference from Comparative Example 1. In the illustrated example, the difference amount was 1500 N. This corresponds to the effect of suppressing the belt tension and the belt tension fluctuation with respect to Comparative Example 1 of Example 1. In the illustrated example, the inhibitory effect reached about 32%. In FIG. 13, the value of the belt tension (scale on the vertical axis) is not shown.

(Discussion)
The belt tension (belt tension of the touch pulley 205 on the tension side) is most excessive during the combustion explosion in each cylinder during cranking (about 1 second), especially at the time of the first in-cylinder explosion (a in the figure). It was found to increase and fluctuate most excessively (see FIG. 13).
As shown in the evaluation results (judgment) shown in Table 5, focusing on the first explosion in the cylinder (a in the figure), the magnitude and fluctuation range of the belt tension (belt tension of the touch pulley 205 on the tension side) are It was found that Example 1 was significantly smaller than that of Comparative Example 1, and that an excessive increase in belt tension and an excessive fluctuation in belt tension could be effectively suppressed.

(Obtained effect)
(1) In the first embodiment, from the outer rotating body 2 at the time of the first in-cylinder explosion (see a in FIG. 13) in which the rotational speed of the outer rotating body 2 temporarily greatly increases at the time of cold engine start. Of the torque transmitted to the inner rotating body 3, a torque larger than the normal torque is not transmitted (see i in FIG. 13). This is when a torque (slip torque Tsb (30 Nm) or more) larger than that at the time of inputting the normal torque is input to the outer rotating body 2 in the direction of expanding the diameter of the entire spring of the spring 4 and the spring 5. In addition, the outer rotating body 2 is suddenly accelerated with almost no engaging action between the inner rotating body 3 and the spring 4 (between B1b1) and between the inner rotating body 3 and the spring 5 (between B2b2). Because it was possible to prevent the impact load (excessive rotational braking force) from acting on the belt 250 on the torque input side by idling (sliding) as it is and trying to suddenly accelerate the inner rotating body 3 with large inertia. it is conceivable that.

(2) As a result, in the first embodiment, when the external rotating body suddenly accelerates and the spring is twisted in the diameter expansion direction at the time of cold engine start, the clutch operates between B1b1 and B2b2, and the auxiliary drive belt. It has been found that it is possible to effectively suppress the excessive increase in belt tension and the excessive fluctuation in belt tension that occur when an excessive torque is applied to the outer rotating body when the engine is cold-started, which is a particular problem in the system.

(3) In Comparative Example 1, the torque transmitted from the outer rotating body to the inner rotating body at the time of sudden acceleration of the outer rotating body is larger than the normal torque. This is because in the configuration of Comparative Example 1, in which the clutch does not operate and the lock mechanism operates when the outer rotating body is suddenly accelerated, when an excessive torque is input to the outer rotating body, the torque is larger than that when the normal torque is input. In a state where there is almost no engagement between the rotating body and the spring, the outer rotating body cannot slip (slip) in the sudden acceleration state, so an attempt is made to suddenly accelerate the inner rotating body with a large inertia. It is probable that it was impossible to prevent the impact load (excessive rotational braking force) from acting on the belt on the torque input side.

(4) Further, in the pulley structure 1 of the first embodiment, the torsional torque of the entire spring of the spring 4 and the spring 5 is the slip torque Tsa (-45 Nm) in the contraction direction or the slip torque Tsb (slip torque Tsb) in the diameter expansion direction. While it does not reach 30 Nm) (see FIG. 5), torque is transmitted between the outer rotating body 2 and the inner rotating body 3 via the spring 4 and the spring 5, and the spring constant k1 (torque curve). The spring 4 and the spring 5 are twisted in the circumferential direction according to the inclination), so that the tension fluctuation of the belt is appropriately suppressed.
Therefore, the pulley structure 1 of the first embodiment has a driving pattern other than the engine start by the ISG in the ISG system, for example, during assisted driving by the ISG (input torque: for example, -35 to -30 Nm) or by the ISG. It can be inferred that the pulley for ISG can operate without any problem even during power generation (input torque: for example, 15 to 25 Nm).

(5) Further, the pulley structure 1 of Example 1 was able to keep the axial length of the outer rotating body 2 to about 90 (exponent) as compared with Comparative Example 1 (index 100). As a result, it was found that the pulley structure 1 could be prevented from increasing in size in the direction of the rotation axis as compared with Comparative Example 1 (conventional 2).

1 Pulley structure 2 Outer rotating body 3 Inner rotating body 4 First coil spring 5 Second coil spring A1 Rear end side region (first end side region)
B1 front end side area (first other end side area)
C1 middle area (first middle area)
A2 rear end side area (second end side area)
B2 front end side area (second other end side area)
C2 middle area (second middle area)
6 End cap 7 Rolling bearing 8 Slide bearing 9 Space 10 Thrust plate a1 Pressure contact surface (clutch engagement part)
a2 pressure contact surface b1 pressure contact surface (clutch engagement part)
b2 Pressure contact surface (clutch engagement part)

Claims (2)

A cylindrical outer rotating body around which the belt is wrapped, and
An inner rotating body provided inside in the radial direction of the outer rotating body and capable of relative rotation with respect to the outer rotating body about the same rotation axis as the outer rotating body.
A first coil spring provided between the outer rotating body and the inner rotating body and compressed in the axial direction along the rotation axis, and a first coil spring.
A pulley structure comprising a second coil spring that is juxtaposed radially inward with respect to the first coil spring and is axially compressed along the axis of rotation.
The first coil spring is
On one end side, the first one end side region where the outer peripheral surface comes into contact with one of the outer rotating body and the inner rotating body by the self-elastic restoring force in the diameter expansion direction in a state where no external force is applied to the pulley structure. When,
On the other end side, the inner peripheral surface comes into contact with the other of the outer rotating body and the inner rotating body by the self-elastic restoring force in the radial direction in a state where no external force is applied to the pulley structure. The end area and
Between the first one end side region and the first other end side region, both of the outer rotating body and the second coil spring during relative rotation between the outer rotating body and the inner rotating body. Has a first middle region that does not come into contact,
When the first coil spring is twisted in the radial direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the outer peripheral surface of the first one end side region is said to be the outer peripheral surface. Sliding with respect to one of the outer rotating body and the inner rotating body,
When the first coil spring is twisted in the diameter expansion direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the inner peripheral surface of the first other end side region is formed. , Sliding with respect to the other of the outer rotating body and the inner rotating body,
The second coil spring is
On one end side, the second end side where the outer peripheral surface contacts the first end side region of the first coil spring by the self-elastic restoring force in the diameter expansion direction in a state where no external force is applied to the pulley structure. Area and
On the other end side, the inner peripheral surface comes into contact with the outer rotating body and the other side of the inner rotating body by the self-elastic restoring force in the radial direction in a state where no external force is applied to the pulley structure. The other end area and
Between the second one end side region and the second other end side region, both the first coil spring and the inner rotating body during relative rotation between the outer rotating body and the inner rotating body. Has a second middle region that does not come into contact,
When the second coil spring is twisted in the radial direction and a torque of a predetermined value or more is transmitted between the outer rotating body and the inner rotating body, the outer peripheral surface of the second one end side region is said to be the outer peripheral surface. Sliding with respect to the outer rotating body and the inner rotating body via the first one end side region of the first coil spring,
When the second coil spring is twisted in the diameter expansion direction and a predetermined torque or more is transmitted between the outer rotating body and the inner rotating body, the inner peripheral surface of the second other end side region becomes. , The pulley structure is configured to slide with respect to the other of the outer rotating body and the inner rotating body. In a state where no external force is applied to the pulley structure, the self-elastic restoring force in the expansion direction in the first one end side region is larger than the self-elastic restoring force in the contraction direction in the first other end side region. Is getting bigger,
In a state where no external force is applied to the pulley structure, the self-elastic restoring force in the expansion direction in the second one end side region is larger than the self-elastic restoring force in the contraction direction in the second other end side region. The pulley structure according to claim 1, wherein the pulley structure is configured to be large.

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