JP2000179634A - Automatic tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the wear of a washer part of a resin washer without damaging the damping force to be generated from a sliding part by setting the coefficient of friction between a slip off preventive plate and at least one part of the resin washer to be smaller than the coefficient of friction between the sliding part and a shaft part of a fixed member. SOLUTION: As a rotary member 2 is rotated, a sliding friction is generated between a front plate 13 on the fixed side and a thrust washer 14 on the rotating side. The front plate 13 is surface-treated by a resin film 13a containing FTPE, and the coefficient of friction between the washer part of the thrust washer 14 and the front plate is smaller than the coefficient of friction between a block part 21 and a shaft part 1a of a fixed member 1. Thus, the advancement of the wear of the washer part through the sliding friction with the front plate 13 is suppressed on the whole. On the other hand, the damping force to be generated by the block part 21 is not damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto-tensioner having a function of damping a tension maintaining operation of an auxiliary driving belt of an automobile engine, for example, and more particularly to a measure for increasing a damping force.

[0002]

2. Description of the Related Art An automatic tensioner of this type is, for example, disclosed in Japanese Patent Publication No. Sho 62-2182, in an accessory drive device of a serpentine layout of an automobile engine, in which a drive pulley and a plurality of driven pulleys are provided. This is used to keep the tension of one belt wound around the belt constant, suppress the vibration (fluttering) of the belt, and stably transmit the rotational force of the driving pulley to all the driven pulleys.

More specifically, as shown in FIGS. 12 and 13, the auto tensioner includes a fixing member A fixed to a fixed body such as an automobile engine, and the fixing member A.
13 is rotatably supported around a rotation axis P by a boss b externally fitted from the front end side (upper end side in FIG. 13) of the shaft section a. Dynamic axis P
Rotating member B having a belt pressing pulley d rotatable about an axis Q parallel to the shaft member Q, and a boss b of the rotating member B
A damping member C is slidably externally fitted to the boss b and fixed non-rotatably to the fixing member A, and the fixing members A and The rotating member B is interposed between the rotating members B, and urges the rotating member B to rotate in the belt pressing direction (clockwise direction in FIG. 12) by the torsional torque around the rotating axis P, while the fixing member A side. And a torsion coil spring D for pressing a part of the damping member C in the circumferential direction against the boss b by a reaction force of the torsion torque with the tongue e (hereinafter referred to as a fixed side tongue e) as a fulcrum. A retaining plate g is attached to the tip of the shaft portion a of the fixing member A, and the boss portion b of the rotating member B is prevented from being removed by the retaining plate g via a resin washer h.

When a sliding resistance is generated between the inner peripheral surface of the damping member C and the outer peripheral surface of the boss b with the rotation of the rotating member B, the magnitude of the sliding resistance is increased. Utilizes the fact that it increases or decreases in response to the reaction force of the torsion torque of the torsion coil spring D that changes according to the rotation position of the rotation member B. Vibration is suppressed efficiently.

[0005]

However, in order to increase the damping force in the above-mentioned conventional auto tensioner,
There is no other choice but to increase the pressing force of the torsion coil spring D against the damping member C or increase the shaft diameter. In either case, there is a problem that the auto tensioner itself must be increased.

Accordingly, the present applicant has filed an earlier application (Japanese Patent Application No.
No. 164355), a sliding portion that rotates integrally with the rotating member B is provided between the torsion coil spring D and the shaft portion a of the fixing member A. The shaft portion a can be slid by the reaction force of the torsion torque with the tongue f on the rotating member B side (hereinafter referred to as the rotation side tongue f) as a fulcrum, instead of the reaction force of the torsion torque with the side tang e as the fulcrum It is suggested to be pressed against.

According to this proposed example, in addition to the reaction force of the torsion torque with the fixed side tongue e as a fulcrum, the reaction force with the rotation side tongue f as a fulcrum can be utilized, so that the auto tensioner itself can be enlarged. Without doing so, it is possible to achieve high damping. Further, the sliding portion is integrally formed with the resin washer h, so that it is possible to avoid a complicated assembling operation when the sliding portion is provided as a new member.

However, this does not mean that there is no room for improvement in the above proposed example. That is, in the proposed example, when the sliding portion is integrally formed with the resin washer h, when the sliding portion slides on the shaft portion a of the fixed member A, the sliding portion is the main body of the resin washer h. The washer slides with respect to the retaining plate g, and the sliding friction causes the washer to wear quickly, thereby shortening the wear life. In particular, when a resin material having a high frictional property is used to increase a new damping force by the sliding portion, the wear life of the washer portion is further shortened. On the other hand, the thickness of the washer may be increased by an amount corresponding to the shortened wear life.
When the washer portion is made thicker, the rotating member B is displaced in the axial direction by that amount, which causes a new problem that the position of the pulley d with respect to the belt T is shifted.

The present invention has been made in view of the above points, and a main object of the present invention is to provide a boss portion of a rotating member externally fitted on a shaft portion of a fixed member via a resin washer by a retaining plate. The torsion coil spring is pressed against the boss portion by a reaction force about the fixed side tongue of the torsion torque of the torsion coil spring, thereby damping the rotation of the rotation member. When the sliding portion that generates a new damping force by being pressed against the shaft portion by the reaction force with the fulcrum of the rotation side tongue of the torsion torque as a fulcrum against the auto tensioner is integrally formed with the resin washer, the sliding portion is used. An object of the present invention is to suppress abrasion due to friction between a washer portion and a retaining plate without impairing a damping force.

[0010]

In order to achieve the above object, according to the present invention, a friction coefficient between a retaining plate and a resin washer is determined by a friction coefficient between a sliding portion and a shaft portion of a fixed member. In this way, the abrasion of the washer portion of the resin washer is suppressed while securing a new damping force by the sliding portion.

More specifically, according to the first aspect of the present invention, a fixing member which has a shaft portion and is fixed to a fixed body is provided on the shaft portion of the fixing member so as to be rotatable from the tip side thereof. A rotating member that has a boss portion to be fitted, has a belt pressing portion over which the belt is runnable, and is rotatably supported by the fixed member at the boss portion, A retaining plate attached to the distal end of the shaft portion for retaining the boss of the rotating member from the shaft portion, and a resin washer interposed between the retaining plate and the boss of the rotating member. A damping member fitted on the boss portion of the rotating member so as to be slidable to the boss portion and non-rotatably fixed to the fixing member; and a state in which the damping member is fitted externally on the damping member. Interposed between the fixed member and the rotating member,
The torsion torque around the rotation axis urges the rotation member to rotate in the belt pressing direction, and the reaction force of the torsion torque with the fixed side tongue as a fulcrum causes a part of the circumferential direction of the damping member to become the boss portion. A torsion coil spring to be pressed and a rotation member are provided between the torsion coil spring and the shaft of the fixed member so as to rotate integrally with the rotation member, and are integrally formed with the resin washer. An auto-tensioner provided with a sliding portion slidably pressed against the shaft portion by a reaction force of the torsional torque serving as a fulcrum is premised.

The friction coefficient between the retaining plate and at least a part of the resin washer is set to be lower than the friction coefficient between the sliding portion and the shaft of the fixed member.

In the above configuration, the belt abutting on the belt pressing portion of the auto tensioner is provided with tension by the torsion torque of the torsion coil spring. Then, the rotating member of the auto tensioner tries to rotate so that the tension of the belt is kept constant. At this time, a damping force by the damping member acts on the rotation of the rotating member. That is, due to the reaction force of the torsion torque with the fixed side tongue as a fulcrum, a part of the damping member in the circumferential direction is pressed against the boss of the rotating member, and a sliding resistance is generated between the two. The resistance damps the rotation of the rotation member. Further, the sliding portion is pressed against the shaft portion of the fixed member due to the reaction force of the torsion torque with the rotation side tongue serving as a fulcrum, and a sliding resistance is generated between the two. The rotation of the member is damped.

On the other hand, with the rotation of the rotating member, sliding resistance also occurs between the retaining plate on the fixed side and the washer portion as the main body of the resin washer on the rotating side. The wear of the washer portion of the resin washer tends to proceed faster than when the sliding portion is separate from the resin washer. At this time, since the friction coefficient between the retaining plate and at least a part of the resin washer is lower than the friction coefficient between the sliding portion and the shaft portion of the fixing member, the friction coefficient between the retaining plate and the washer portion is reduced. The progress of wear due to friction is suppressed as a whole, while the damping force generated by the sliding portion is not impaired.

According to a second aspect of the present invention, in the first aspect of the present invention, at least a sliding contact surface of the retaining plate with the resin washer is formed of a resin film containing a lubricant.

In the above configuration, at least the sliding contact surface of the retaining plate with the resin washer is formed of a resin film containing a lubricant, whereby the coefficient of friction between the retaining plate and the resin washer is reduced. It is set lower than the friction coefficient between the sliding part and the shaft part. Therefore, the operation according to the first aspect of the invention can be performed specifically and appropriately.

According to a third aspect of the present invention, in the first aspect of the present invention, at least a sliding contact surface of the retaining plate with the resin washer is formed by plating containing a lubricant.

In the above construction, at least the sliding contact surface of the retaining plate with the resin washer is formed by plating containing a lubricant, whereby the coefficient of friction between the retaining plate and the resin washer is reduced. It is set lower than the friction coefficient between the moving part and the shaft part. Therefore, similarly to the case of the second aspect of the present invention, the operation of the first aspect of the present invention is specifically and appropriately performed.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the resin washer is disposed on a side opposite to the retaining plate in the axial direction and has a sliding portion integrally formed with the opposite plate side member. The anti-plate side member is provided so as to be relatively non-rotatable on the side of the retaining plate and has a lower frictional property than the anti-plate side member.

In the above construction, the resin washer is disposed on the side opposite to the axial retaining plate and the sliding member is integrally formed with the opposite plate side member, and the retaining plate of the opposite plate side member is provided. The plate-side member has a lower friction characteristic than the opposite plate-side member, so that the gap between the resin washer and the retaining plate is reduced. Is set lower than the friction coefficient between the sliding portion and the shaft portion. Therefore, also in the present invention, the operation according to the first aspect of the present invention is specifically and appropriately performed.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the resin washer is disposed radially inward and the sliding member is integrally formed with the inner peripheral member. And an outer peripheral member that is arranged outward in the direction and has lower friction characteristics than the inner peripheral member.

In the above configuration, the resin washer includes an inner peripheral member integrally formed with a sliding portion and an outer peripheral member. The outer peripheral member has a lower friction characteristic than the inner peripheral member, whereby the friction coefficient between the outer peripheral portion of the resin washer and the retaining plate is smaller than the friction coefficient between the sliding portion and the shaft portion. Is also set low. Therefore, similarly to the case of the invention of the fourth aspect, the operation of the invention of the first aspect is specifically and appropriately performed.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the resin washer is disposed radially outward and the sliding member is integrally formed with the outer peripheral member. And an inner peripheral member having lower friction characteristics than the outer peripheral member.

In the above construction, the resin washer has an outer peripheral member integrally formed with a sliding portion and an inner peripheral member, contrary to the fifth aspect of the present invention. And the inner peripheral member has a lower friction characteristic than the outer peripheral member, whereby the friction coefficient between the inner peripheral side portion of the resin washer and the retaining plate is reduced by the friction coefficient between the sliding portion and the shaft portion. It is set lower than. Therefore, similarly to the case of the fourth and fifth aspects of the present invention, the operation of the first aspect of the present invention is specifically and appropriately performed.

According to a seventh aspect of the present invention, in the above fourth to sixth aspects, the material having low friction characteristics is made of a resin containing a lubricant.

In the above structure, the member having low friction characteristics (the plate side member in the case of the invention of claim 4, the outer peripheral member in the case of the invention of claim 5, and the inner peripheral member in the case of the invention of claim 6) ) Is made of a resin containing a lubricant, which imparts low friction characteristics. Therefore,
The functions of the inventions of claims 4 to 6 are specifically performed.

According to an eighth aspect of the present invention, in the second, third and seventh aspects, the lubricant is PTFE (polytetrafluoroethylene).

In the above configuration, the plate-side member, the outer peripheral member, and the inner peripheral member are made of a resin containing PTFE as a lubricant, thereby providing low friction characteristics. Therefore, the functions of the inventions of the second, third and seventh aspects are properly performed.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIGS. 3 to 5 show the entire configuration of an auto-tensioner according to Embodiment 1 of the present invention. This auto-tensioner is attached to an automobile engine and, for example, one auto-tensioner is driven by an output shaft of the engine. Used in a serpentine driving device that drives a plurality of engine accessories via the belt T.

As shown in detail in FIG. 1, the auto tensioner has, as basic components, a fixing member 1 having a shaft portion 1a and fixed to an automobile engine.
A belt pressing portion which has a boss portion 2a rotatably fitted from the front end side (the upper end side in FIG. 3) of the shaft portion 1a and a belt T (see FIG. 3) is runably traversed. A rotary member 2 having a pulley 2b as a base member and supported by the fixed member 1 at the boss portion 2a so as to be rotatable around a rotary axis P, and a boss portion 2a of the rotary member 2 A spring support 3 as a damping member which is slidably externally fitted to the boss portion 2a and non-rotatably fixed to the fixing member 1, and a fixing member which is externally fitted on the spring support 3; 1 and the rotation member 2, and the rotation member 2 is rotated by a torsional torque about the rotation axis P.
Is rotated in the belt pressing direction (clockwise direction in FIG. 3), and a part of the spring support 3 in the circumferential direction is pressed against the boss 2a by the reaction force of the torsional torque with the fixed tongue 4a as a fulcrum. And a torsion coil spring 4.

More specifically, the fixing member 1 is made of a metal such as an aluminum alloy, and has a bottomed cylindrical shape having an opening at the upper side (hereinafter simply referred to as the upper side) in FIG. And the shaft portion 1a is provided with the cup portion 5.
Is provided so as to extend upward from the center of the bottom wall along the rotation axis P. At the outer periphery of the cup portion 5, mounting pieces 6, 6 each having a bolt hole are provided so as to protrude outward in the radial direction. Further, on the inner surface of the cup portion 5, an unillustrated locking portion for locking the fixed side tongue 4a of the torsion coil spring 4 in the circumferential direction is provided. On the other hand, a front plate 13 as a disc-shaped metal retaining plate is attached to the tip of the shaft portion 1a by caulking or the like. A bolt hole 7 is provided in the shaft portion 1a so as to penetrate the shaft portion 1a in the axial direction, and the fixing member 1 is provided between the shaft portion 1a and the mounting pieces 6, 6.
Are bolted to the engine. Further, the outer peripheral surface of the shaft portion 1a is formed in a tapered cross-section having a gradually decreasing diameter toward the tip of the shaft portion 1a, and the outer peripheral surface is provided with a key groove 8 extending in the axial direction. .

An insert bearing 9 made of a synthetic resin, which is a damping member different from the spring support 3, is externally fitted to the shaft portion 1a of the fixed member 1. The insert bearing 9 has a substantially cylindrical shape with both upper and lower ends opened, and its inner and outer peripheral surfaces are both formed in a tapered cross-section with a small diameter at the upper end side. A part of the inner circumference of the insert bearing 9 in the circumferential direction is engaged with the key groove 8 of the shaft portion 1a and
Is provided so as to extend along the rotation axis P. On the other hand, the portion of the insert bearing 9 on the side opposite to the key portion 10 in the circumferential direction is a thin portion in which the outer peripheral portion is cut off substantially 180 ° in the circumferential direction, and the upper end of the thin portion is formed. The side portion is a cutout portion 9a cut out over the entire thin portion in the circumferential direction.

The rotating member 2 is made of a metal such as an aluminum alloy as in the case of the fixed member 1. In addition to the boss 2a, the lower side of FIG. And a cup 11 arranged so that the opening thereof is axially opposed to the opening of the cup 5 of the fixing member 1, and the boss 2 a is formed from the center of the bottom wall of the cup 11. It is provided so as to extend downward in FIG. 1 along the rotation axis P, and is rotatably fitted to the shaft portion 1 a of the fixed member 1 via an insert bearing 9. The boss 2a is prevented from being pulled out by the front plate 13 via a resin-made thrust washer 14 as a resin washer. On the other hand, on the inner surface of the cup part 11, an unillustrated locking part for locking the rotating tongue 4b of the torsion coil spring 4 in the circumferential direction is provided. A cutout portion 20 is provided in a part of the boss portion 2a and the cup portion 11 in the circumferential direction, penetrating the boss portion 2a in the radial direction and penetrating the bottom wall of the cup portion 11 in the axial direction. Specifically, the cutout portion 20 extends from the tongue 4b on the rotation side of the torsion coil spring 4 in the winding direction of the torsion coil spring 4 (clockwise direction in FIG. 3).
Are disposed at positions separated by approximately 90 °.

Further, the rotating member 2 includes a cup 11
The arm member 12 is provided on the outer periphery of the arm member so as to protrude outward in the radial direction. The pulley 2b is integrated with the rotating member 2 below the tip of the arm portion 12. It is provided so as to rotate. That is, the arm 1
A shaft 16 is provided at the end of the shaft 2 so as to protrude downward. In this shaft 16, a pulley 2 b is connected via a ball bearing 17 to an axis parallel to the rotation axis P of the rotation member 2. It is supported rotatably around Q. The inner ring of the ball bearing 17 is attached to the shaft 16 by a bolt 18 via a disk-shaped dust shield 19.

The main body of the spring support 3 has a cylindrical shape with upper and lower ends opened, and is disposed with a predetermined clearance between itself and the boss 2 a of the rotating member 2. The spring support 3 has an outward flange-shaped flange 3a at the opening edge on the lower side of the main body.
The flange portion 3a is disposed between the bottom wall of the cup portion 5 of the fixing member 1 and the end of the coil portion of the torsion coil spring 4 on the fixing member 1 side.

The torsion coil spring 4 has a right-handed coil and is interposed between the fixed member 1 and the rotating member 2 while being compressed in the axial direction. At this time, the flange portion 3a of the spring support 3 is sandwiched between the end of the coil portion on the fixing member 1 side and the bottom wall of the cup portion 5 of the fixing member 1, so that, The spring support 3 is non-rotatably fixed to the fixing member 1. Further, the thrust washer 14 is pressed against the front plate 13 by the compression force.

Further, the torsion coil spring 4 is interposed between the fixed member 1 and the rotating member 2 in a state where the coil diameter is reduced, and the torsion coil spring 4 is rotated by the torsion torque in the direction in which the coil diameter increases. Is urged to rotate in the belt pressing direction. That is, the torsion coil spring 4 uses the fixed-side tongue 4a as a fulcrum, and applies the torsional torque in the urging direction to the rotating member 2 at the rotating-side tongue 4b. Then, due to the reaction force of the torsion torque with the fixed-side tongue 4a as a fulcrum, a part of the spring support 3 in the circumferential direction is pressed inward in the radial direction and pressed against the boss 2a of the rotating member 2. As a result, the boss portion 2 a is also pressed inward in the radial direction and is pressed against the insert bearing 9.

Between the torsion coil spring 4 and the shaft portion 1a, a block portion 21 as a sliding portion integrally formed with the thrust washer 14 is disposed. The block portion 21 is slidably pressed against the shaft portion 1a by a reaction force about the pivot side tongue 4b of the torsion torque of the torsion coil spring 4 as a fulcrum. Specifically, the block portion 21 is disposed in the cutout portion 20 of the rotating member 2, and thereby rotates integrally with the rotating member 2. Further, the block unit 21 includes, as shown in FIG.
The inner and outer peripheral surfaces are each formed in an arc-shaped cross section, the radius of curvature of the inner peripheral surface is substantially the same as that of the outer peripheral surface of the boss 2a, and the radius of curvature of the outer peripheral surface is the coil portion of the torsion coil spring 4. Are set substantially the same as in the case of the inner peripheral surface, so that the cutout 9a of the insert bearing 9 can be penetrated in the radial direction and pressed against the shaft portion 1a.

In this embodiment, as shown in FIG. 2, the entire surface of the front plate 13 is formed of a resin film 13a containing PTFE as a lubricant. The friction coefficient between the thrust washer 13 and the thrust washer 14 is set lower than the friction coefficient between the block portion 21 and the shaft portion 1a.

Next, the operation of the auto tensioner configured as described above will be described. In the above-mentioned auto tensioner, a tension due to the torsion torque of the torsion coil spring 4 is applied to the belt T contacting the pulley 2b. Then, the rotating member 2 tries to rotate so that the tension of the belt T is kept constant. At this time, a damping force by the spring support 3 and the insert bearing 9 acts on the rotation of the rotating member 2. That is, due to the reaction force of the torsion torque on the fixed side tongue 4a as a fulcrum, a part of the spring support 3 in the circumferential direction is provided on the boss 2a of the rotating member 2, and the boss 2a is provided on the insert bearing 9a.
Respectively, and sliding resistance is generated between the inner peripheral surface of the spring support 3 and the outer peripheral surface of the boss portion 2a, and between the inner peripheral surface of the boss portion 2a and the outer peripheral surface of the insert bearing 9, respectively. The rotation of the rotating member 2 is damped by the sliding resistance. Further, the reaction force of the torsion torque about the pivot side tongue 4b as a fulcrum makes the block 2
1 is pressed against the shaft portion 1a of the fixed member 1, and a sliding resistance is generated between the two.
Is damped.

On the other hand, with the rotation of the rotating member 2, sliding friction is also generated between the front plate 13 on the fixed side and the thrust washer 14 on the rotating side.
The wear of the washer portion, which is the main body portion of the thrust washer 14, tends to progress faster than the case where the block portion is separate from the thrust washer in the proposal example described in the section of the problem to be solved by the invention. At this time, the front plate 13 has been surface-treated with the resin film 13a containing FTPE, and the friction coefficient between the front plate 13 and the washer of the thrust washer 13 is smaller than that of the block 21 and the fixing member 1.
Is smaller than the friction coefficient between the washer and the shaft portion 1a, so that the progress of abrasion due to the sliding friction of the washer with the front plate 13 is suppressed as a whole, while the damping force generated by the block 21 is reduced. It is not spoiled. Specifically, when the front plate has no resin coating, the amount of wear of the washer portion of the thrust washer 14 at the time when the same usage time as when the amount of wear of the washer reaches 0.5 mm is as follows. One fifth of 0.1
mm. The initial damping value of the entire auto tensioner was substantially the same as the above case.

Therefore, according to the present embodiment, the turning member 2 is urged to turn in the belt pressing direction by the torsion torque of the torsion coil spring 4 with respect to the fixing member 1, while the tongue 4a of the torsion torque is fixed. The spring support 3 is pressed against the boss portion 2a of the rotating member 2 and the boss portion 2a is pressed against the insert belling 9 by the reaction force acting as a fulcrum, thereby generating sliding resistance. In the auto-tensioner configured to dampen the movement, the reaction force of the torsional torque with the rotation side tongue 4b as a fulcrum is pressed against the shaft portion 1a of the fixed member 1 and
When the block portion 21 for generating a sliding resistance is formed integrally with the thrust washer 14, the thrust washer 14 treats the front plate 13 with a resin film 13a containing a lubricant. Therefore, abrasion of the washer portion of the thrust washer 14 can be suppressed without damaging the damping force newly generated by the block portion 21.

In the above embodiment, the surface of the front plate 13 is formed of the resin film 13a containing PTFE, but may be formed of a resin film containing a lubricant other than PTFE. Further, instead of such a resin film, it may be formed by plating containing a lubricant such as PTFE, so that the wear of the washer portion can be suppressed to about 2/3.

In the above-described embodiment, the entire surface of the front plate 13 is formed by the resin film 13a. However, the resin film 13a may be formed at least on the sliding contact surface with the thrust washer 14. Good.

(Embodiment 2) FIG. 6 shows a main part of an auto-tensioner according to Embodiment 2 of the present invention. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals.

In this embodiment, the thrust washer 14
As shown in FIGS. 7 and 8, the anti-plate side member 14a is disposed on the side opposite to the front plate 13 in the axial direction (the lower side in FIG. 6), and the block portion 21 is integrally formed. And a plate-side member 14b which is disposed on the front plate 13 side (upper side in FIG. 6) of the opposite plate-side member 14a and has a lower friction characteristic than the opposite plate-side member 14a. Therefore, the friction coefficient between the front plate 13 and the thrust washer 14 is made lower than the friction coefficient between the block portion 21 and the shaft portion 1a.

Specifically, the plate side member 14b
Is made of, for example, nylon 4-6 containing PTFE, while the non-plate side member 14a is made of nylon 6-6.
-6. The thickness of the plate side member 14b and the thickness of the washer portion of the opposite plate side member 14a are both １ ／ of the thickness of the conventional thrust washer. The plate side member 14b is provided with locking holes 22, 22,... Penetrating in the axial direction at a plurality of positions (three positions in the illustrated example) in the circumferential direction, while the front surface of the opposite plate side member 14a is provided. On the surface on the plate 13 side (upper surface in the figure), projections 23, 23,... For engaging the corresponding locking holes 22 and connecting the opposite plate side member 14a so as to be relatively non-rotatable are provided. Is provided. It should be noted that, unlike the case of the first embodiment, the front plate 13 is surface-treated by ordinary plating not containing a lubricant. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

In the auto tensioner configured as described above, the thrust washer 14 is provided on the plate-side member 14b disposed on the front plate 13 side and on the side of the plate-side member 14b opposite to the front plate 13 side. The opposite plate-side member 14a is disposed, and the plate-side member 14b and the opposite plate-side member 14a are engaged with each other so that they cannot rotate relative to each other. The block portion 21 is formed integrally with the opposite plate-side member 14a, and the plate-side member 14b has lower friction characteristics than the opposite plate-side member 14a, so that the front plate 13 and the thrust washer are formed. 14 is set lower than the friction coefficient between the block portion 21 and the shaft portion 1a.

Therefore, according to the present embodiment, the same effects as those of the first embodiment can be obtained.

(Embodiment 3) FIG. 9 shows a main part of an auto-tensioner according to Embodiment 3 of the present invention. In this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals.

In this embodiment, the thrust washer 14
As shown also in FIGS. 10 and 11, the inner peripheral member 14c is disposed radially inward and the block portion 21 is integrally formed, and is disposed radially outward of the inner peripheral member 14c. Further, it is combined with an outer peripheral member 14d having a friction characteristic lower than that of the inner peripheral member 14c.

More specifically, the inner peripheral member 14c is made of, for example, nylon 6-6, while the outer peripheral member 14d is made of nylon 6-6.
Is, for example, nylon 4 containing PTFE as a lubricant.
-6. The thickness of the washer portion of the inner peripheral member 14c and the thickness of the outer peripheral member 14d are the same as the thickness of the conventional thrust washer. The front plate 13 is surface-treated by ordinary plating as in the case of the second embodiment. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

In the auto tensioner configured as described above, the thrust washer 14 includes an outer peripheral member 14d disposed radially outward and an inner peripheral member 14c disposed radially inward of the outer peripheral member 14d. Are combined. And the block part 21 is the inner peripheral member 1.
4c, the outer peripheral member 14d has lower frictional characteristics than the inner peripheral member 14c, so that the front plate 13 and the thrust washer 14
Is set lower than the friction coefficient between the block portion 21 and the shaft portion 1a.

Therefore, according to the present embodiment, the same effects as those of the first embodiment can be obtained.

In the above embodiment, the thrust washer 14 is replaced with the inner peripheral member 14 having the block portion 21 formed integrally.
c and an outer peripheral member 14d having a lower frictional property than the inner peripheral member 14c, but the outer peripheral member 14d is disposed radially outward and slides. An outer peripheral member in which a portion is integrally formed, and an inner peripheral member which is arranged radially inward of the outer peripheral member and has a lower friction characteristic than the outer peripheral member may be combined. Good.

[0056]

As described above, according to the first aspect of the present invention, the fixing member fixed to the fixed body, and the fitting member which is externally fitted on the shaft of the fixing member and is provided with the retaining plate through the resin washer. A rotating member which is rotatably supported by the boss portion which is prevented from being pulled out and presses the belt by the belt pressing portion, and which is externally fitted on the boss portion of the rotating member and non-rotatably fixed to the fixing member And the damping member is externally fitted on the damping member and is interposed between the fixed member and the rotating member. The torsional torque urges the rotating member to rotate in the belt pressing direction while the torsion torque A torsion coil spring that presses a part of the damping member in the circumferential direction to the boss by a reaction force with the fixed side tongue as a fulcrum, and is provided between the torsion coil spring and the shaft so as to rotate integrally with the rotation member. And resin washer Are integrally formed, with respect to auto-tensioner having a sliding portion which is pressed slidably on the shaft portion by the reaction force to pivot the pivoting side tongue of the torsional torque,
Since the friction coefficient between the retaining plate and at least a part of the resin washer is set to be lower than the friction coefficient between the sliding portion and the shaft portion, the damping force newly generated by the sliding portion is reduced. Wear of the washer portion of the resin washer can be suppressed without any loss.

According to the second aspect of the present invention, at least the sliding contact surface of the retaining plate with the resin washer is formed of a resin film containing a lubricant. It can be obtained specifically and appropriately.

According to the third aspect of the present invention, at least the sliding contact surface of the retaining plate with the resin washer is formed by plating containing a lubricant. The effect of the first aspect of the invention can be specifically and appropriately obtained.

According to the fourth aspect of the present invention, the resin washer is connected to the opposite plate-side member integrally formed with the sliding portion,
The plate-side member having a lower friction characteristic than the opposite plate-side member is used. Therefore, according to the present invention, the effect of the first aspect can be specifically and appropriately obtained. .

According to the fifth aspect of the present invention, the resin washer includes an inner peripheral member integrally formed with a sliding portion, and an outer peripheral member having lower friction characteristics than the inner peripheral member. Thus, the effect of the first aspect of the invention can be specifically and appropriately obtained in the same manner as in the case of the fourth aspect of the invention.

According to the sixth aspect of the present invention, the resin washer includes an outer peripheral member integrally formed with a sliding portion and an inner peripheral member having a lower friction characteristic than the outer peripheral member. Therefore, the effects of the first aspect of the invention can be specifically and appropriately obtained in the same manner as in the fourth and fifth aspects of the invention.

According to the seventh aspect of the invention, the member having the low friction characteristic is made of a resin containing a lubricant. Can be obtained.

According to the eighth aspect of the present invention, the lubricant is
Since PTFE is used, the effects of the inventions of claims 2, 3 and 7 can be properly obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view taken along line II of FIG.

FIG. 2 is a perspective view showing a thrust washer.

FIG. 3 is a plan view showing the auto tensioner according to the first embodiment of the present invention.

FIG. 4 is a bottom view showing the auto tensioner.

FIG. 5 is a side view showing the auto tensioner.

FIG. 6 is a view corresponding to FIG. 1 showing a main part of an auto tensioner according to a second embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a thrust washer.

FIG. 8 is a vertical sectional view showing a thrust washer.

FIG. 9 is a view corresponding to FIG. 1 showing a main part of an auto-tensioner according to Embodiment 3 of the present invention.

FIG. 10 is an exploded perspective view showing a thrust washer.

FIG. 11 is a longitudinal sectional view showing a thrust washer.

FIG. 12 is a plan view showing a conventional auto tensioner with a part thereof cut away.

FIG. 13 is a sectional view taken along line XIII-XIII of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed member 1a Shaft part 2 Rotating member 2a Boss part 2b Pulley (belt pressing part) 3 Spring support (damping member) 4 Torsion coil spring 4a Fixed tongue (tangible on fixed member side) 4b Rotary tongue (rotated) 13) Front plate (prevention plate) 13a Resin film 14 Thrust washer (resin washer) 14a Non-plate side member 14b Plate side member 14c Inner peripheral member 14d Outer peripheral member 21 Block portion (sliding portion) P Rotating shaft heart

Claims (8)

[Claims] 1. A fixing member having a shaft portion and fixed to a fixed body, a boss portion rotatably fitted on a shaft portion of the fixing member from a tip side thereof, and a belt capable of running. A rotating member rotatably supported by the fixing member at the boss portion; and a rotating member attached to a tip of a shaft portion of the fixing member, the rotating member being rotated from the shaft portion. A retaining plate for retaining the boss portion of the member, a resin washer interposed between the retaining plate and the boss portion of the rotating member, and a boss portion of the rotating member on the boss portion. A damping member slidably fitted externally and non-rotatably fixed to the fixed member; and a damping member interposed between the fixed member and the rotating member in a state fitted over the damping member, The belt pressing part presses the belt against the rotating member by the torsional torque around the dynamic axis. A torsion coil spring that presses a part of the damping member in the circumferential direction against the boss portion by a reaction force of the torsion torque with the tongue on the fixed member side as a fulcrum, and the torsion coil spring And the shaft of the fixed member are provided so as to rotate integrally with the rotating member, and are integrally formed with the resin washer, and are provided on the rotating member side with respect to the torsional torque of the torsion coil spring. A sliding portion slidably pressed against the shaft portion by a reaction force having the tongue as a fulcrum, and a friction coefficient between the retaining plate and at least a part of the resin washer is determined by the sliding portion An auto-tensioner, wherein a coefficient of friction between the fixing member and a shaft is set to be lower. 2. The auto-tensioner according to claim 1, wherein at least a sliding contact surface of the retaining plate with the resin washer includes:
An auto-tensioner formed of a resin film containing a lubricant. 3. The auto-tensioner according to claim 1, wherein at least a sliding contact surface of the retaining plate with the resin washer is:
An auto tensioner characterized by being formed by plating containing a lubricant. 4. The auto-tensioner according to claim 1, wherein the resin washer is disposed on a side opposite to the retaining plate in the axial direction,
An anti-plate-side member integrally formed with a sliding portion; and a plate-side member provided on the anti-plate-side member on the side of the retaining plate so as to be relatively non-rotatable, and having a lower friction characteristic than the anti-plate-side member. An auto-tensioner, comprising: 5. The auto-tensioner according to claim 1, wherein the resin washer is disposed radially inward, and an inner peripheral member integrally formed with a sliding portion is disposed radially outward of the inner peripheral member. And an outer peripheral member having lower frictional characteristics than the inner peripheral member. 6. The auto-tensioner according to claim 1, wherein the resin washer is disposed radially outward, and an outer peripheral member integrally formed with a sliding portion is disposed radially inward of the outer peripheral member; An auto-tensioner comprising an inner peripheral member having lower friction characteristics than the outer peripheral member. 7. The auto-tensioner according to claim 4, wherein the member having low friction characteristics is made of a resin containing a lubricant. 8. The auto-tensioner according to claim 2, wherein the lubricant is polytetrafluoroethylene.