JP2000130470A - One-way clutch - Google Patents

Abstract

(57) [Summary] An alternator shaft of an alternator in which torque of a crankshaft rotating with a minute angular velocity variation due to an explosion stroke of an automobile engine is transmitted through a transmission belt,
When attaching the one-way clutch built-in pulley A which is constantly pressed by the leaf spring 6 so that the sprag 5 tilts in the direction of biting between the inner and outer rings 1 and 2 without increasing the pressing force M of the leaf spring 6. The force for tilting the sprags 5 in the biting direction can be increased, so that the followability of the sprags 5 at the time of an increase in angular velocity in a high-frequency minute angular velocity fluctuation in a high-speed rotation range of the engine can be enhanced without difficulty. SOLUTION: The center of gravity G on the swing plane of each sprag 5 is defined as:
The centrifugal force caused by the rotation of the inner and outer wheels 1 and 2 with respect to the reference line L connecting the sliding contact point P with the outer wheel 2 and the rotation center of the inner and outer wheels 1 and 2 when the torque transmission on the swing plane of the sprag 5 is cut off. By F, the sprag 5 is set at a circumferential position where the sprag 5 is tilted in a direction of biting between the inner and outer rings 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque transmission path for transmitting the torque of a crankshaft of an automobile engine that rotates with a minute angular velocity fluctuation to an accessory shaft of an accessory via a transmission belt. The present invention relates to a direction clutch, and more particularly, to a measure for improving the followability of a sprag when an angular velocity is increased in a high-frequency minute angular velocity vibration.

[0002]

2. Description of the Related Art For example, as described in Japanese Patent Application Laid-Open No. 61-228153, a torque transmission path for transmitting the torque of a crankshaft of an automobile engine to an accessory shaft of an accessory through a transmission belt is disclosed. It is known that the provision of the directional clutch can reduce the load on the power transmission belt by absorbing the minute angular velocity fluctuation of the torque caused by the explosion stroke of the engine. In particular, when the auxiliary device is an alternator, the effect of reducing the belt load is large because the inertia torque of the rotor is large.

[0003] At this time, the high-frequency minute angular velocity fluctuations in the high-speed rotation range of the engine (for example, 5000 rpm) have a small amplitude and are sufficiently absorbed by the elasticity of the transmission belt, so that the load on the transmission belt is also reduced. On the other hand, a small angular velocity fluctuation of a low frequency in a low-speed rotation range of the engine (for example, during idling) is large, and a large load is applied to the transmission belt. In particular, emphasis is placed on absorbing low-frequency minute angular velocity fluctuations in the low-speed rotation range of the engine.

Here, the structure of a conventional one-way clutch provided in the torque transmission path will be described. As shown schematically in FIG. 4, this is perpendicular to the rotation axis of the inner and outer wheels a and b between the inner and outer wheels a and b assembled so as to be relatively rotatable by the relative rotation of the inner and outer wheels a and b. A plurality of sprags c, c,... (Only one is shown in the drawing) that swings in a plane to connect and disconnect the torque transmission between the inner and outer wheels a, b are arranged.

For example, when the torque from the crankshaft is inputted to the outer wheel b, the sprags c are driven by the relative rotation of the outer wheel b in the locking direction when the angular speed is increased due to the minute angular speed fluctuation of the crankshaft. The torque is transmitted between the inner and outer wheels a and b by tilting in the direction of biting between the wheels a and b (clockwise direction in FIG. 4), while, when the angular velocity decreases, the inner and outer wheels a are rotated by the relative rotation of the outer wheel b in the free direction. , B in such a manner as to tilt in the direction of sliding contact (counterclockwise direction in the figure) to cut off the torque transmission.
Further, in order to surely tilt each sprag c in the direction of biting between the inner and outer rings a and b during the relative rotation in the locking direction, a leaf spring is used so that the sprag c does not slip between the inner and outer rings a and b. The pressing force M of d is always applied.

[0006]

However, in the above-described conventional one-way clutch, each sprag c cannot sufficiently follow a minute angular velocity variation of a high frequency (for example, 160 to 170 Hz) in a high speed rotation range of the engine. Therefore, there is a drawback that slippage easily occurs between each sprag c and the inner and outer rings a and b. That is, the sprags c generate vibrations that cause slippage between the inner and outer races a and b due to the minute angular velocity fluctuations. The tilt in the direction of biting into the tire becomes insufficient.

Therefore, the plate thickness of each of the leaf springs d is increased to increase the pressing force M on each of the sprags c, thereby suppressing the vibration of each of the sprags c and inclining the sprags c in the biting direction. It is conceivable to do so.
However, when the plate thickness of the leaf spring d is increased, the leaf spring d
Is also increased by that amount, resulting in another problem that the leaf spring d is easily broken. Therefore, it is actually difficult to increase the pressing force M of each leaf spring d. It is.

The present invention has been made in view of the above points, and a main object of the present invention is to provide a leaf spring so that a sprag can be tilted in a direction in which a sprag bites between an inner and an outer ring in a torque transmission path with a minute angular speed variation. When a one-way clutch that is constantly pressed by a pressing mechanism such as is provided, the force for tilting the sprag in the biting direction can be increased without increasing the pressing force of the pressing mechanism. It is an object of the present invention to improve the sprag follow-up property when the angular velocity is increased in the case of a high-frequency minute angular velocity fluctuation in a high-speed rotation range of an engine when used in a belt-type accessory drive device of an engine.

[0009]

In order to achieve the above object, according to the present invention, a force for inclining a sprag in a direction in which the sprag bites between the inner and outer rings by utilizing a centrifugal force accompanying rotation of the inner and outer rings. I did it.

Specifically, according to the first aspect of the present invention, an inner ring, an outer ring rotatably mounted on the inner ring,
Each of the inner and outer wheels is arranged between the inner and outer wheels so as to be swingable in a plane orthogonal to the rotation axis of the inner and outer wheels. A plurality of sprags that incline in the direction of sliding contact with the spurs to interrupt the torque transmission, and a plurality of pressing mechanisms that constantly press each of the sprags to incline in a direction in which the corresponding sprags bite between the inner and outer wheels, respectively. The clutch is a precondition.

The center of gravity of the sprags on the swing plane is set at a position where the sprags are tilted in a direction in which the sprags bite between the inner and outer wheels due to centrifugal force caused by rotation of the inner and outer wheels.

In the above configuration, when a relatively high-speed rotation torque is input to the one-way clutch arranged on the torque transmission path accompanied by the minute angular velocity fluctuation, if the pressing force of the pressing mechanism is insufficient, When the inner and outer wheels rotate relative to each other in the locking direction when the angular speed is increased due to the minute angular speed fluctuation, each sprag does not tilt sufficiently in the direction in which it bites between the inner and outer wheels, causing a slip between the inner and outer wheels. This makes it difficult to transmit torque through sprags between the inner and outer wheels.

At this time, the center of gravity of the sprags on the swinging plane is located at a position where the sprags are tilted in a direction in which the sprags bite between the inner and outer wheels due to centrifugal force caused by rotation of the inner and outer rings. In addition to the pressing force of the corresponding pressing mechanism, a tilting force in the biting direction due to the centrifugal force acts on. As a result, for example, with respect to the input torque accompanied by a relatively high frequency minute angular velocity variation such as in the case of a high-speed rotation range of an automobile engine, the force for tilting the sprag in the biting direction is increased, and the vibration of the sprag is suppressed. Therefore, it is possible to easily improve the followability of the sprag when the angular velocity increases in the minute angular velocity fluctuation.

According to a second aspect of the present invention, in the first aspect of the present invention, the center of gravity of each sprag on the swing plane is a sliding contact between the outer ring and the inner and outer rings when torque transmission on the swing plane of the sprag is interrupted. It is assumed that the sprags are set at circumferential positions where the sprags are tilted in a direction in which the sprags bite between the inner and outer wheels by a centrifugal force caused by rotation of the inner and outer wheels with respect to a reference line connecting the rotation center of the inner and outer wheels.

In the above configuration, when the inner and outer wheels are relatively rotating in the free direction, each sprag is tilted in a direction in which the sprags are in sliding contact with the inner and outer wheels to interrupt the transmission of torque between the inner and outer wheels. When the relative rotation direction of the inner and outer rings changes in the locking direction, the center of gravity of each sprag moves relative to a reference line connecting the sliding contact with the outer ring and the rotation center of the inner and outer rings when the torque transmission is interrupted. The sprags are present at circumferential positions where the sprags are tilted in a direction of biting between the inner and outer rings by the centrifugal force accompanying the above. Therefore, the tilting force in the biting direction due to the centrifugal force accompanying the rotation of the inner and outer wheels can always be obtained.

According to the third aspect of the present invention, the first and second aspects are provided.
The one-way clutch according to the invention is arranged in a torque transmission path for transmitting torque of a crankshaft rotating with a minute angular speed variation due to an explosion stroke of an automobile engine to an accessory shaft of an accessory via a transmission belt. And

In the above configuration, when a torque accompanied by a minute angular velocity fluctuation is input to the one-way clutch from the crankshaft of the automobile engine, when the angular velocity in the minute angular velocity fluctuation is increased, the inner and outer wheels rotate relative to each other in the locking direction and each of them rotates. While the sprags are tilted in the direction of biting between the inner and outer wheels, when the angular velocity is reduced, the inner and outer wheels are relatively rotated in the free direction to tilt each sprag in a direction in which the sprags are in sliding contact with the inner and outer wheels. At this time, in addition to the pressing force of the corresponding pressing mechanism, the tilting power in the biting direction due to the centrifugal force accompanying the rotation of the inner and outer rings always acts on each of the sprags. Therefore, the vibration of the sprags due to the insufficient pressing force of the pressing mechanism is suppressed with respect to the high frequency minute angular velocity fluctuation in the high speed rotation range of the engine, and the sprag has a high follow-up property when the angular velocity increases in the minute angular velocity fluctuation. Become.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a pulley for winding a transmission belt around the outer ring is provided.

In the above configuration, a pulley for winding the transmission belt is provided around the outer periphery of the outer ring of the one-way clutch, and the pulley with a built-in one-way clutch is formed. Is attached to, for example, an accessory shaft of an accessory, thereby forming a torque transmission path between the crankshaft of the automobile engine and the accessory shaft of the accessory via the transmission belt. Therefore, the operation according to the third aspect of the invention is properly performed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 schematically shows a layout of a belt-type accessory drive device of an automobile engine provided with a pulley A with a built-in one-way clutch according to an embodiment of the present invention. A drive pulley 21 and an alternator 22 are disposed at one end of a four-cylinder four-cycle engine 20 mounted on a crankshaft 20a which rotates with a slight change in angular velocity caused by an explosion stroke of the engine 20. A so-called serpentine layout in which one V-ribbed belt 23 as a transmission belt is wound in a meandering manner between a plurality of driven pulleys attached to each auxiliary shaft of a plurality of auxiliary machines including the auxiliary pulley. is there.

Specifically, the driving pulley 21 shown in FIG.
The pulley 24 of the auto tensioner, the pulley 25 for the hydraulic pump of the power steering device, the idler pulley 26, the pulley 27 for the compressor of the air conditioner, and the pulley 28 for the engine cooling fan are shown in the order of the running direction of the V-ribbed belt 23 indicated by arrows. Is arranged. The one-way clutch built-in pulley A is disposed between the tension pulley 24 of the auto tensioner and the hydraulic pump pulley 25 of the power steering device.
The rotor is mounted on an alternator shaft 22a of the alternator 22 having a relatively large inertia torque.

The pulley A with a built-in one-way clutch is shown in FIG.
As shown in FIG. 2, an inner ring 1 attached to the alternator shaft 22a so as to rotate integrally therewith, and a pulley 3 around which a V-ribbed belt 23 is wound around the outer periphery are provided so as to rotate integrally, and are rotatable relative to the inner ring 1. And steel balls 4a, 4 arranged between the inner and outer rings 1 and 2 on a single plane orthogonal to the rotation axis of the inner and outer rings.
, and a single row bearing 4 consisting of a deep groove ball bearing having a ring-shaped retainer 4b for rollingly holding the steel balls 4a, 4a,. It is arranged so as to be swingable in a plane orthogonal to the rotation axis, and is tilted in a direction (clockwise in FIG. 1) that bites between the inner and outer wheels 1 and 2 to transmit torque between the inner and outer wheels 1 and 2. On the other hand, the sprags 5, which incline in the direction of sliding contact with the inner and outer rings 1 and 2 (counterclockwise direction in FIG.
, And leaf springs 6, 6,... As pressing mechanisms for constantly pressing the corresponding sprags 5 so as to incline in a direction of biting between the inner and outer rings 1 and 2, respectively.

The retainer 4b of the single-row bearing 4 has a retaining hole 7 having a circular cross-section provided to penetrate in the radial direction.
, and holding holes 7b, 7b,... having a rectangular cross section similarly provided so as to penetrate in the radial direction are arranged at a predetermined pitch in the circumferential direction in a fixed pattern (for example, alternately). The former holding holes 7a, 7a,... Accommodate steel balls 4a, 4a,..., And the latter holding holes 7b, 7b,. That is, the steel balls 4a, 4a,...
, Are arranged in the same plane. The outer peripheral surface 1a of the inner race 1 and the inner peripheral surface 2a of the outer race 2 have
Deep grooves 1b, 2b having an arc-shaped cross section for guiding the steel balls 4a, 4a,.

Of the two circumferentially opposed inner wall surfaces of each holding hole 7b for accommodating the sprags 5, 5,..., The left inner wall surface in FIGS. A guide surface 8 is provided to guide the sprag 5 slidably. Each of the retainers 4b has a corresponding holding hole 7b.
A resin-made retainer body 9 having a plurality of concave portions that are open at one axial end (lower side in FIG. 2) so as to form three inner wall surfaces, and one axial end of the retainer main body 9 And an auxiliary plate 10 joined so as to form the remaining inner wall surfaces of the holding holes 7b. Further, the corresponding holding hole 7b is formed in the holder main body 9 at the other axial end (upper side in FIG. 2).
Are provided respectively with insertion holes 11 that are opened.

Each of the leaf springs 6 is bent from one ring-shaped leaf spring material 12 joined to the other end face in the axial direction of the retainer body 9 to one end side in the axial direction. The guide surface 8 of the holding hole 7b is arranged so as to be inserted between the inner wall surface 13 on the opposite side in the circumferential direction and the sprag 5 via the insertion hole 11, whereby the sprag 5 is brought into contact with the guide surface 8. Pressing is always performed in the pressing direction. The leaf spring 6 is formed in a tapered shape in which the width dimension gradually decreases toward the distal end.

Each of the sprags 5 is provided on the outer peripheral surface 1 a of the inner race 1.
And the respective contact surfaces of the outer ring 2 with the inner peripheral surface 2a are cam surfaces 5a, 5a.
b, the outer ring 2 is tilted by the relative rotation in accordance with the relative rotation direction of the outer ring 2 with respect to the inner ring 1. That is, when the outer wheel 2 relatively rotates in the locking direction when the angular speed is increased due to the minute angular speed fluctuation of the crankshaft 20a, each sprag 5 tilts in the direction of biting between the inner and outer wheels 1 and 2 by the relative rotation, while the angular speed decreases. Occasionally, when the outer ring 2 relatively rotates in the free direction, the outer ring 2 tilts in a direction in which it slides on the inner and outer rings 1 and 2 by the relative rotation.

The portion of the sprag 5 which receives the pressure of the leaf spring 6 is a convex portion 5c provided so as to expand toward the leaf spring 6. On the other hand, the pressing force of the leaf spring 6 The portion of the sprag 5 pressed against the guide surface 8 by M is a contact surface 5d having a substantially arc-shaped cross section which can slide on the guide surface 8. The contact surface 5d is provided so as to be located on the outer peripheral side with respect to the protrusion 5c, whereby the pressing force M of the leaf spring 6 received by the sprag 5 is reduced.
Is converted into a tangential tilting force acting on a contact point on a swing plane with the guide surface 8. In other words, by this tilting power, the sprags 5 bite between the inner and outer wheels 1 and 2 while moving the contact point with the guide surface 8 to the outer peripheral side along the guide surface 8 when the outer ring 2 is relatively rotated in the locking direction. To tilt.

In the present embodiment, the center of gravity G on the swing plane of each sprag 5 tilts in a direction in which the sprag 5 bites between the inner and outer rings 1 and 2 by the centrifugal force F accompanying the rotation of the outer ring 2. The position is set in the circumferential direction.

Specifically, the center of gravity G corresponds to the outer race 2 when the torque transmission on the swing plane of the corresponding sprag 5 is cut off.
The sprag 5 is moved between the inner and outer rings 1 and 2 by a centrifugal force caused by the rotation of the inner and outer rings 1 and 2 with respect to a reference line L connecting the sliding contact point P with the center of rotation of the inner and outer rings 1 and 2 (not shown). It is set to a position in the circumferential direction (the position on the left side in FIG. 1) in which it is tilted in the direction of biting into the horn.

Here, the operation of the pulley A with a built-in one-way clutch constructed as described above will be described. In the serpentine-type accessory drive device of the automobile engine 20,
V-ribbed belt 2 from crankshaft 20a of engine 20
When a torque accompanied by a minute angular velocity fluctuation is input to the outer ring 2 of the pulley A with a built-in one-way clutch via the centrifugal force F caused by the rotation of the inner and outer rings 1 and 2, the sprag 5 Is located at a position where it is tilted in the direction of biting between the inner and outer rings 1, 2, so that each sprag 5 has a centrifugal force F due to the rotation of the outer ring 2 in addition to the pressing force M of the corresponding leaf spring 6.
Accordingly, the tilting force T for tilting in the direction of biting between the inner and outer wheels 1 and 2 always acts.

Therefore, according to the present embodiment, the torque of the crankshaft 20a that rotates with a minute angular speed variation due to the explosion stroke of the automobile engine 20 is applied to the V-ribbed belt 2
The sprags 5, 5,... Arranged between the inner and outer rings 1, 2 are swingably arranged on the alternator shaft 22a of the alternator 22, which is transmitted through the inner and outer rings 1, 2 by the corresponding leaf springs 6.
When the one-way clutch built-in pulley A is constantly pressed so as to be tilted in the direction of biting between the two sprags 5, the center of gravity G of each sprag 5 is moved to the outer ring 2 on the swing plane of the sprag 5 when torque transmission is interrupted. The sprags 5 bite between the inner and outer rings 1 and 2 by a centrifugal force F caused by the rotation of the inner and outer rings 1 and 2 with respect to a reference line L connecting the sliding contact point P with the center of rotation of the inner and outer rings 1 and 2. Since the tilting position is set to the circumferential position, the tilting power in the biting direction with respect to the sprag 5 can be increased irrespective of the magnitude of the pressing force M of the leaf spring 6, so that the vehicle engine 20 High frequency in the high speed rotation range (for example, 160 rpm at 5000 rpm)
The followability of each sprag 5 when the angular velocity increases in a minute angular velocity fluctuation (up to 170 Hz) can be improved without difficulty.

In the above embodiment, the case where the inner and outer rings 1 and 2 are assembled so as to be relatively rotatable via the single row bearing 4 formed of a deep groove ball bearing has been described.
The type of the bearing for assembling the bearing 2 so as to be relatively rotatable is not particularly limited.

In the above embodiment, the leaf springs 6, 6,
.. Constitute a pressing mechanism for the sprags 5, 5,.
Any known technique other than... Can be appropriately adopted.

Further, in the above-described embodiment, the case of the pulley A with a built-in one-way clutch in which the pulley 3 is provided on the outer periphery of the outer ring 2 has been described, but the present invention relates to a plane orthogonal to the rotation axes of the inner and outer rings 1 and 2. Can be applied to any one-way clutch in which the sprags 5, 5,...

[0035]

As described above, according to the first aspect of the present invention, the motor is tilted in the direction of biting between the inner and outer wheels to transmit torque between the inner and outer wheels, while tilting in the direction of sliding contact with the inner and outer wheels. Swingable sprags that block the torque transmission
In a one-way clutch which always presses so as to tilt in a direction of biting between the inner and outer wheels by a pressing mechanism, the center of gravity of the sprag on the swing plane is tilted in the biting direction by centrifugal force caused by rotation of the inner and outer wheels. Since it is set to the position, regardless of the magnitude of the pressing force of the pressing mechanism, it is possible to increase the inclination power in the biting direction with respect to the sprag, and therefore, for input torque accompanied by high-frequency minute angular velocity vibration, The followability of the sprags when the angular velocity increases due to the minute angular velocity fluctuation can be easily improved.

According to the second aspect of the present invention, the center of gravity of the sprag is set with respect to the reference line connecting the sliding contact with the outer ring and the center point of the inner and outer rings. It is possible to always obtain the tilting power of the sprag in the biting direction due to the centrifugal force.

According to the third aspect of the present invention, the one-way clutch transmits the torque of the crankshaft rotating with a minute angular speed variation due to the explosion stroke of the automobile engine to the auxiliary machine shaft of the auxiliary machine via the transmission belt. Since it is arranged in the torque transmission path, it is possible to improve the sprag followability of the sprag at the time of an increase in the angular velocity in the high frequency minute angular velocity fluctuation in the high speed rotation range of the engine.

According to the fourth aspect of the present invention, since the pulley for the transmission belt to be wound around is provided on the outer periphery of the outer race, the effect of the third aspect of the invention can be properly obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged side view showing a main part of a pulley with a built-in one-way clutch according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a schematic diagram showing a serpentine-type accessory drive device of an automobile engine.

FIG. 4 is an enlarged view of a main part of a conventional one-way clutch, corresponding to FIG.

[Explanation of symbols]

 Reference Signs List 1 inner ring 2 outer ring 3 pulley 5 sprag 6 leaf spring (pressing mechanism) 20 automobile engine 20a crankshaft 22 alternator (auxiliary machine) 22a alternator shaft (auxiliary shaft) 23 V-ribbed belt (transmission belt) A pulley with one-way clutch (one-way) Clutch) G Center of gravity P Sliding contact L Reference line M Pressing force F Centrifugal force T Tilt power (due to centrifugal force)

Continued on the front page (72) Inventor Hirofumi Miyata 3-2-15-1 Meiwa-dori, Hyogo-ku, Kobe-shi, Hyogo Inside BANDO CHEMICAL CO., LTD. (72) Inventor Shinichiro Nishikawa 3-2-1, Meiwa-dori, Hyogo-ku, Kobe-shi, Hyogo No. Bando Kagaku Co., Ltd. (72) Inventor Masakazu Domoto 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture, Japan Inside (72) Inventor Masahiko Sato 1578 Higashikaizuka, Iwata City, Shizuoka Prefecture, Japan

Claims (4)

[Claims] 1. An inner ring, an outer ring assembled relative to the inner ring so as to be relatively rotatable, and respectively arranged between the inner and outer rings so as to be swingable in a plane orthogonal to a rotation axis of the inner and outer rings. A plurality of sprags that incline in a direction to bite into and transmit torque between the inner and outer wheels, and tilt in a direction of sliding contact with the inner and outer wheels to cut off the torque transmission; A one-way clutch comprising a plurality of pressing mechanisms for constantly pressing so as to incline in a direction of biting into the sprags. The one-way clutch is set at a position where it is tilted in a direction to bite between the inner and outer wheels. 2. The one-way clutch according to claim 1, wherein the center of gravity of each sprag on the swing plane is a sliding contact between the outer ring and the center of rotation of the inner and outer rings when torque transmission on the swing plane of the sprag is interrupted. A one-way clutch set at a circumferential position where the sprags are tilted in a direction in which the sprags bite between the inner and outer wheels by a centrifugal force caused by rotation of the inner and outer wheels with respect to a reference line connecting the two. 3. The one-way clutch according to claim 1, wherein the torque of the crankshaft rotating with a minute angular speed variation due to the explosion stroke of the vehicle engine is transmitted to the auxiliary shaft of the auxiliary through a transmission belt. A one-way clutch, which is disposed on a transmission path. 4. The one-way clutch according to claim 3, wherein a pulley for winding a transmission belt is provided on an outer periphery of the outer race.