JPH074483A - Auto tensioner - Google Patents

Abstract

(57) [Summary] [Purpose] A new adjustable damping force can be added to the damping force specific to the auto tensioner, and the damping force of the entire auto tensioner can be adjusted accordingly. An adjusting bolt which is threadably supported by a support piece 12 extending to an opening edge of a front cup portion 2a of a rotating member 2 and is capable of pressing the outer peripheral surface of a rear cup portion 1a of a fixed member 1 by a tip portion 13b. 13 is provided. The adjusting bolt 13
Is screwed by a turning operation of the bolt head 13a from the outside, so that the pressing force of the bolt tip portion 13b on the outer peripheral surface of the rear cup portion 1a changes, and the turning resistance of the turning member 2 changes. . In addition, the sliding contact member 14 is attached to the surface of the portion of the outer peripheral surface of the rear cup 1a that is pressed by the bolt tip 13b.
Affix.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to apply a predetermined tension to a V-belt or the like for driving an auxiliary machine by an automobile engine and to automatically change the damping force according to the variation of the tension. The present invention relates to an automatic tensioner, and more particularly to an automatic tensioner whose damping force can be adjusted from the outside.

[0002]

2. Description of the Related Art An autotensioner of this type is generally known, for example, as shown in U.S. Pat. No. 4,473,362, and a span between pulleys of a belt wound between a drive pulley and a plurality of driven pulleys is known. Press
It is used to transfer the rotational force of the drive pulley to all driven pulleys.

As shown in FIG. 4, the conventional automatic tensioner has a fixing member A having a shaft portion a extending in the axial direction and fixed to a fixed body such as an automobile engine, and the fixing member A. The shaft portion a has a boss portion c that is externally fitted so as to be able to slide and rotate from the tip end side thereof through a tubular resin member b as a sliding contact member, and the tip end is parallel to the axis of the boss portion c. An arm portion e that rotatably supports the pulley d at its center is provided in a protruding manner, and a rotating member B is rotatably supported by the fixing member A at the boss portion c, the fixing member A and the rotating member B. And a torsion coil spring C interposed between the rotating member B and the rotating member B to press the belt on the pulley d by the rotating biasing force to apply a predetermined tension, and It is designed to change the damping force.

That is, when the belt is wound around the pulley d, the belt force (reaction force applied from the belt to the pulley f) between the tubular resin member b and the boss portion c of the rotating member B is generated. And the urging force of the torsion coil spring C are combined to generate a damping force that resists the rotation of the rotating member B. Then, in this state, when the tension of the belt fluctuates in the decreasing direction, the damping force becomes small due to the decrease of the belt force, and thus the followability of the pulley d to the belt becomes high and the tension decrease of the belt is prevented. It On the other hand, with respect to the tension of the belt, the damping force also increases due to the increase in the belt force, which gives a large resistance force to the pulley d and prevents the belt from fluttering.

[0005]

However, in the above-mentioned conventional auto tensioner, the damping force is set uniformly depending on the characteristics of the tubular resin member and the torsion coil spring used, and therefore the damping force is adjusted. In order to do so, it is necessary to disassemble and change the internal structure, and there is the problem that it is difficult to adjust the damping force after assembly.

The present invention has been made in view of the above problems, and its main purpose is to improve the structure of the autotensioner so as to add a new damping force that can be adjusted to the damping force specific to the autotensioner. It is possible to adjust the damping force of the auto tensioner as a whole.

[0007]

In order to achieve the above object, in the invention of claim 1, the rotary member is provided with a changeable rotary resistance, and the rotary tensioner allows adjustment to the autotensioner. Added new damping force.

Specifically, in the present invention, a shaft portion is provided,
A fixing member that can be fixed to a fixed body, a boss portion that is externally fitted to the shaft portion of the fixing member from the tip end side of the shaft portion through a tubular resin member, and a pulley that presses the belt at the tip end is provided. A rotation member rotatably supported by an axis parallel to the axis of the boss, the rotation member rotatably supported by the fixing member at the boss, the fixing member and the rotation member. A torsion coil spring interposed between the rotating member and the fixed member for rotating and biasing the rotating member in a predetermined direction. The rotating biasing force of the rotating member causes the belt to be pressed against the pulley by a predetermined amount. It is premised on an autotensioner that applies the tension of 1 and changes the damping force according to the variation of the tension.

A resistance imparting means is provided for imparting resistance to the rotation of the rotating member with respect to the fixed member and varying the rotating resistance by an external operation.

And a torsion coil spring for urging the member to rotate in a predetermined direction with respect to the fixed member. The rotating urging force of the rotating member presses the belt against the pulley to apply a predetermined tension, and The premise is an auto tensioner that changes the damping force according to the fluctuation of the tension.

A pressing member is provided which is supported by one of the fixed member and the rotating member and slidably presses the other of the fixed member and the rotating member. In addition, the pressing member is displaceable in the pressing direction, and the relative rotation between the fixed member and the rotating member is suppressed according to the pressing force that changes due to the displacement. Further, the pressing member is provided with an operating portion for displacing the pressing member in the pressing direction exposed to the outside.

According to a second aspect of the present invention, in the first aspect of the invention, the rotation of the rotating member is stopped and locked when the rotation resistance of the rotating member by the resistance applying means is maximized. .

In the invention of claim 3, the above-mentioned claim 1 or 2
In the invention described above, the resistance applying means is a bolt which is screwably supported by one of the fixing member and the rotating member and whose tip portion can press the other of the fixing member and the rotating member. And
The rotation resistance of the rotating member is made variable by screwing the bolt with the head to change the pressing force applied to the fixing member or the rotating member at the tip.

According to a fourth aspect of the present invention, in the third aspect of the invention, one of the bolt tip portion and a portion of the bolt tip portion that receives pressure is provided with a sliding contact member that slides in contact with the other.

According to a fifth aspect of the invention, in the third aspect of the invention, at least one of the bolt, the fixing member and the rotating member is made of synthetic resin.

[0016]

With the above construction, in the invention of claim 1, the resistance imparting means imparts rotation resistance to the fixed member of the rotation member in the auto tensioner, and the rotation resistance suppresses rotation of the rotation member. As a result, a new damping force is applied to the auto tensioner, and as a result, the damping force of the entire auto tensioner is the inherent damping force plus the above new damping force. The turning resistance of the turning member is variable by an external operation, and the newly applied damping force can be adjusted, so that the damping force of the entire auto tensioner can be easily adjusted. The damping force can be adjusted without disassembling the auto tensioner.

According to the second aspect of the invention, when the rotation resistance of the rotation member by the resistance applying means becomes maximum, the rotation of the rotation member is stopped and locked. That is, in the stop locked state of the rotating member, the pulley supported by the tip of the arm portion of the rotating member is in a fixed state, and the auto tensioner can function as a fixed tensioner.

According to the third aspect of the present invention, the bolt as the resistance applying means threadably supported by one of the fixing member and the rotating member so as to be screwed through presses the other of the fixing member and the rotating member at its tip. However, the rotation resistance of the rotating member can be obtained by the frictional force between the tip portion of the bolt and the fixed or rotating member.
Then, by screwing the bolt by operating the head, the pressing force on the other of the fixing member and the rotating member at the tip portion changes, and thereby a new adjustable damping force can be applied to the auto tensioner. .

According to the invention of claim 4, since the sliding contact member is provided on one of the tip of the bolt and the portion of the bolt which receives the pressure, the tip of the bolt and the fixing member or the rotating member are provided. Is smoothly slid through the sliding contact member, which makes it possible to change the turning resistance while ensuring the smooth turning of the turning member.

According to the fifth aspect of the present invention, since at least one of the bolt and the fixing member or the rotating member is made of synthetic resin, both the sliding contact between the bolt tip and the other of the fixing member or the rotating member are slidable. At least one of the parts is made of synthetic resin. Therefore, since the synthetic resin portion smoothly slides in contact with the other sliding contact portion, smooth rotation of the rotating member is ensured without using a sliding contact member as a separate component as in the invention of claim 4. .

[0021]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an auto tensioner according to this embodiment, which is composed of a fixing member 1 made of a metal such as an aluminum alloy that can be fixed to a fixing body such as an automobile engine, and the fixing member 1. A rotating member 2 made of metal that is attached and rotatably supported is interposed between the fixing member 1 and the rotating member 2, and the rotating member 2 is fixed.
, And a torsion coil spring 3 that urges it to rotate in a predetermined direction.

The fixing member 1 has a bottomed cylindrical rear cup portion 1a and a shaft portion 4 extending axially from the center of the bottom portion of the rear cup portion 1a, and is fixed to a fixed body at a mounting portion (not shown). It is designed to do. In addition, the wall portion of the rear cup portion 1a is formed with a base end side locking hole (not shown) penetrating the wall portion in the radial direction.

The rotating member 2 has a front cup portion 2a whose opening faces the opening of the rear cup portion 1a,
A boss portion 7 that extends in the axial direction from the center of the bottom portion of the front cup portion 2a and that is externally fitted to the shaft portion 4 of the fixed member 1 from the tip end side thereof via a cylindrical resin member 6 as a damping member. The front boss portion 2a has an arm portion 9 projectingly provided on the outer periphery thereof, and a pulley 8 is rotatably supported at an end of the front cup portion 2a at an axis parallel to the axis of the boss portion 7.
Is rotatably supported by the fixed member 1. Further, the boss portion 7 is prevented from coming off by an unillustrated retaining means at an end portion of the fixing member 1 on the tip end side of the shaft portion 4. Further, a belt to which a predetermined tension is applied, such as a V-belt for driving accessories in an automobile engine, is wound around the pulley 8. A front end side locking hole (not shown) penetrating the wall portion of the front cup portion 2a in the radial direction is formed. Both the inner and outer peripheral surfaces of the tubular resin member 6 are formed in a tapered shape in cross section such that the tip end side has a small diameter, but the outer peripheral surface of the shaft portion 4 and the inner peripheral surface of the boss portion 7 are correspondingly formed. It has a similar sectional taper shape. The tubular resin member 6 is prevented from rotating toward the fixed member 1 by means not shown.

The main body of the above-mentioned torsion coil spring 3 is left-handed, and both ends of the base end side and the tip end side, which are not shown, are projected outward in the radial direction from the main body. The above-mentioned base end side end portion is radiused to the base end side locking hole in the rear cup portion 1a wall portion of the fixing member 1, and the tip end side end portion is to the tip end side locking hole in the front cup portion 2a peripheral wall of the rotating member 2. Each end is restricted from moving in the circumferential direction by each locking hole. The torsion coil spring 3 operates in the direction in which the main body expands with both ends locked,
The rotating member 2 is biased to rotate counterclockwise when viewed from the tip side.

The base end side of the torsion coil spring 3 and the boss portion 7
A cylindrical spring support 11 made of synthetic resin is interposed between and. This spring support 1
The inner peripheral surface of 1 can be slidably contacted with the outer peripheral surface of the boss portion 7. Further, an outward flange 11a that contacts the bottom surface of the rear cup portion 1a is formed at the opening edge of the spring support 11 on the base end side. And the outward flange 11
The spring support 11 is fixed to the fixing member 1 side by pressing a on the bottom surface of the rear cup portion 1a by the pressing force of the torsion coil spring 3. Further, in this fixed state, when the front cup portion 2a is rotated clockwise when viewed from the tip end side, the diameter of the main body of the torsion coil spring 3 is reduced, so that the spring support 11 is tightened and its inner peripheral surface is tightened. Comes into pressure contact with the outer peripheral surface of the boss portion 7,
This also causes the damping force to be generated.

At the opening edge of the front cup portion 2a of the rotating member 2, a support extending radially outward from the front cup portion 2a and then extending toward the base end side along the outer peripheral surface of the rear cup portion 1a of the fixing member 1. The piece 12 is projected. A gap of a certain size is secured between the support piece 12 and the outer peripheral surface of the rear cup portion 1a having a circular cross section.

The supporting member 12 has a rotating member 2 attached thereto.
An adjustment bolt 13 as a resistance applying means for applying a rotational resistance to the head is screwed and supported with the head portion 13a located outside the support piece 12 and the tip portion 13b penetrating so as to face the center of the fixing member 1. Has been done. Further, a sliding contact member 14 made of a synthetic resin is attached to the area of the outer peripheral surface of the rear cup portion 1a where the bolt tip portion 13b abuts in the circumferential direction. The adjusting bolt 13 is screwed by rotating and operating a head 13a as an operating portion.
By the screwing of 3, the tip portion 13b inside the support piece 12 presses the sliding contact member 14 on the outer peripheral surface of the rear cup portion 1a of the fixing member 1, and the pressing force of the bolt 13 changes according to the amount of screwing. The rotation resistance of the rotation member 2 with respect to the fixed member 1 is variably adjusted according to the pressing force.

Further, in the auto tensioner of this embodiment, when the pressing force of the adjusting bolt 13 is maximized, the bolt tip portion 13a and the sliding contact member 1 on the fixed member 1 side.
The frictional force between the fixed member 1 and the rotating member 2 is set so as to exceed the rotational force applied to the rotating member 2 by the belt reaction force and the torsion coil spring 3. It is designed to be locked in a stopped state.

Therefore, according to this embodiment, when the belt is wound around the pulley 8 of the automatic tensioner, the tubular resin member 6 and the rotating member 2 of the automatic tensioner are wound.
Between the inner peripheral surface of the boss 7 and the spring support 11
Between the inner peripheral surface and the outer peripheral surface of the boss portion 7, the belt force and the urging force of the torsion coil spring 3 are combined to generate a damping force. In this state, when the tension of the belt decreases, the belt force decreases. The damping force becomes smaller due to the decrease of. Then, the rotating member 2 is easily rotated, and the followability of the pulley 8 with respect to the belt is increased, which makes it possible to quickly prevent the tension of the belt from being lowered. on the other hand,
With respect to the tension of the belt, the damping force also increases due to the increase of the belt force, and thus a large resistance force is applied to the pulley 8 and the flapping of the belt can be prevented.

In this embodiment, the adjusting bolt 13
The damping force of the auto tensioner can be adjusted by screwing. That is, when the adjusting bolt 13 is rotated around its head portion 13a, the adjusting bolt 13 is screwed in the penetrating direction with respect to the support piece 12, and by this screwing, the rear cup portion 1 of the fixing member 1 by the bolt tip portion 13b.
The pressing force of the outer peripheral surface against the sliding contact member 14 changes. At this time, the tip portion 13b of the adjusting bolt 13 and the rear cup portion 1a
A frictional force corresponding to the pressing force is generated between the sliding contact member 14 on the outer peripheral surface. Rotational resistance of the rotating member 2 to the fixed member 1 is given by this frictional force, and the rotation of the rotating member 2 is suppressed by this rotating resistance, and a new damping force is added to the damping force specific to the auto tensioner. As a result, the damping force of the auto tensioner as a whole becomes the damping force that is unique to the above-mentioned new damping force. The turning resistance of the turning member 2 is variable according to the pressing force of the bolt tip portion 13, and the newly applied damping force is adjustable, so that the damping force of the entire auto tensioner is adjusted. Can be adjusted.

Moreover, since the above adjustment is performed at the head portion 13a of the adjustment bolt 13 exposed to the outside of the auto tensioner, it is not necessary to disassemble the auto tensioner and change the internal structure, and the adjustment can be easily performed. For example, if the intrinsic damping force of the auto tensioner is set to a value smaller than the design value and the rotation resistance is gradually increased when the auto tensioner is used after assembling, the damping force as a whole is increased. The optimum damping value in the system in which the autotensioner is used can be determined, and the damping value can be set to be optimum.

Further, when the pressing force of the adjusting bolt 13 is increased to the maximum, the frictional force between the bolt tip portion 13a and the sliding contact member 14 is correspondingly increased, and eventually the rotating member 2 is rotated. Will be completely stopped and locked. That is, at this time, if the rotation of the rotation member 2 is stopped while the pulley 8 at the tip of the arm portion 9 presses the belt, the automatic tensioner functions as a fixed tensioner. Thus, for example, when the torsion coil spring 3 inside the auto tensioner is damaged and cannot be used as an auto tensioner, the auto tensioner can be used by switching to a fixed tensioner, and at least the belt is wound. It becomes possible to ensure the transmission of the rotational force between the pulleys. That is, in the case of the V-belt of the automobile engine, it is possible to drive the automobile at least while ensuring the driving of the accessories by the automobile engine.

In the above embodiment, the sliding contact member 14 is attached to the outer peripheral surface of the rear cup portion 1a of the fixed member 1, but it may be integrally provided on the tip portion 13b of the adjusting bolt 13.

Further, in the above embodiment, the sliding contact member 14 is used as a component in order to ensure a smooth sliding contact state between the tip portion 13b of the adjusting bolt 13 and the outer peripheral surface of the rear cup portion 1a of the fixing member 1. However, if at least one of the adjusting bolt 13 and the fixing member 1 is made of synthetic resin, the sliding contact member 14 can be omitted. That is, due to the resinification, at least one of both sliding contact portions between the bolt tip portion 13b and the fixing member 1 which are in direct sliding contact with each other is made into resin, and this synthetic resin portion smoothly slides with the other sliding contact portion. I will touch you,
The rotating member 2 without using the sliding contact member 14 as a component
It is possible to ensure smooth rotation of the.

Further, in the above embodiment, the adjusting bolt 13
Although the rotary member 2 is supported to press the outer peripheral surface of the fixed member 1, the bolt 13 may be supported to the fixed member 1 to press the rotary member 2.

[0036]

As described above, according to the first aspect of the present invention, the resistance imparting means imparts the rotational resistance to the fixed member of the rotary member in the auto tensioner. The damping force can be applied to the automatic tensioner as a whole, and the rotation resistance can be changed by an external operation, so that the damping force of the entire auto tensioner can be easily adjusted without disassembling and changing the internal structure. be able to.

According to the second aspect of the present invention, the rotation resistance of the rotating member by the resistance applying means is maximized so that the rotation of the rotating member is stopped and locked. The pulley supported by can be fixed, and the automatic tensioner can be easily switched to the fixed tensioner by an external operation. As a result, for example, even when the torsion coil spring inside the auto tensioner is damaged and cannot be used as an auto tensioner, the auto tensioner can be used as a fixed tensioner by stopping and locking the rotating member. Transmission of the rotational force by the belt between the two can be ensured.

According to the third aspect of the invention, the rotation imparting means is constituted by a bolt which is supported by one of the fixed member and the rotation member so as to be screwed, and the bolt is screwed by operating the bolt head. Since the rotation resistance can be adjusted by changing the pressing force of the tip of the bolt against the other of the fixing member and the rotating member, the damping force of the auto tensioner can be easily adjusted with a relatively simple structure. it can.

According to the fourth aspect of the present invention, since the tip of the bolt presses the fixed member or the rotating member via the sliding contact member, both can be slid smoothly and the rotating member can be slid. It is possible to ensure smooth rotation of the.

According to the fifth aspect of the present invention, at least one of the bolt, the fixing member, and the rotating member is made of synthetic resin, so that at least one of the bolt tip portion and the portion pressed by the bolt tip portion is synthesized as described above. Since it can be formed of resin, and this synthetic resin portion smoothly slides in contact with the other sliding contact portion, smooth rotation of the rotating member can be achieved without using a sliding contact member as a separate component as in the invention of claim 4. Rotation can be ensured.

[Brief description of drawings]

1 is a cross-sectional view taken along line I-I of FIG.

FIG. 2 is an enlarged cross-sectional view showing a main part of the auto tensioner according to the embodiment of the present invention.

FIG. 3 is a side view showing an auto tensioner.

FIG. 4 is a vertical sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed member 2 Rotating member 3 Torsion coil spring 4 Shaft part 7 Boss part 8 Pulley 9 Arm part 13 Adjustment bolt (resistance imparting means) 13a Head part 13b Tip part 14 Sliding contact member

Claims (5)

[Claims] 1. A fixing member having a shaft portion and capable of being fixed to a fixed body, and a boss portion externally fitted to the shaft portion of the fixing member from a tip end side of the shaft portion through a tubular resin member. A rotating member rotatably supported by the fixed member at the boss portion, the arm portion rotatably supporting the pulley for pressing the belt at the tip end with the axis parallel to the axis of the boss portion. And a torsion coil spring interposed between the fixed member and the rotating member for biasing the rotating member in a predetermined direction with respect to the fixed member, and the rotating biasing force of the rotating member. An automatic tensioner in which a belt is pressed against the pulley to apply a predetermined tension, and a damping force is changed according to a change in the tension, which resists rotation of the rotating member with respect to the fixed member. And the rotation resistance is variable by an external operation. Auto tensioner, characterized in that it comprises a given unit. 2. The auto tensioner according to claim 1, wherein the resistance applying means is configured to stop and lock the rotation of the rotating member when the rotating resistance of the rotating member is maximized. A featured auto tensioner. 3. The auto tensioner according to claim 1 or 2, wherein the resistance applying means is supported by one of the fixing member and the rotating member so as to be screwable, and the tip portion presses the other of the fixing member and the rotating member. It is a possible bolt, and is configured such that the turning resistance of the turning member can be changed by screwing the bolt with the head to change the pressing force to the fixing member or the turning member at the tip end. An auto tensioner that is characterized by 4. The automatic tensioner according to claim 3, wherein one of the bolt tip portion and a portion of the bolt tip portion that receives pressure is provided with a sliding contact member that is in sliding contact with the other. Tensioner. 5. The automatic tensioner according to claim 3, wherein at least one of the bolt, the fixing member and the rotating member is made of synthetic resin.