JP2601506Y2 - Auto tensioner - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION An automatic tensioner according to the present invention is a belt for driving a timing belt of an automobile engine or an auxiliary machine such as an alternator or a compressor (hereinafter, these are simply referred to as a "belt". It is used to give the proper tension to).

[0002]

2. Description of the Related Art In order to drive the camshaft of an OHC or DOHC engine in synchronization with a crankshaft, a driving device using a belt 1 as shown in FIG. 6 is widely used. In FIG. 6, reference numeral 2 denotes a driving pulley that is driven to rotate by a crankshaft of an engine, 3 denotes a driven pulley fixed to an end of a camshaft, and 4 and 4 guide the belt 1 or a water pump. Guide pulley or driven pulley for driving auxiliary equipment such as
This is a pulley for applying an appropriate tension to the pulley.

The pulley 5 is pivotally supported by a swing member 7 that swings about a pivot 6. A spring 8 is provided at an end of a bracket 9 fixed to the swing member 7,
By elastically pressing the pulley 5 toward the belt 1, the tension of the belt 1 is always maintained irrespective of the dimensional change of the belt 1 or the like due to a temperature change or the like, or the vibration accompanying the operation of the engine. I try to keep it constant.

[0004] By the way, a belt 1 is used for an auto tensioner.
In addition to the function of applying tension to the belt 1, a function of holding down the belt 1 is required. That is, in the camshaft driving device shown in FIG. 6, when the driving pulley 2 rotates, a portion of the belt 1 located between the pulleys 2 to 5
It tends to vibrate so as to swing in a direction perpendicular to the traveling direction. If this deflection is allowed as it is, the amplitude of the deflection increases (vibration grows), abnormal vibration occurs in the driving portion driven by the belt 1, or in the case of a toothed belt, so-called tooth jump occurs. Cause problems.

For this reason, conventionally, for example, Japanese Patent Application Laid-Open No. 58-65
As described in JP-A-357-357 and JP-A-63-180759, a damper device is incorporated in an auto tensioner, and the belt 1 is suppressed by the damper device. In order to more reliably prevent the belt 1 from loosening, when the belt 1 is slack, the pulley 5 is quickly followed, and when the belt 1 is taut, the pulley 5 is not retracted. 1 is also disclosed in, for example, JP-A-63-167163, JP-A-2-72252, and 2-80839.
Gazette, JP-A-3-24346, and JP-A-2-1684
No. 6, No. 2-98243, No. 4-39349
As described in Japanese Unexamined Patent Publication (Kokai) No. HEI 10-301, it is conventionally known.

The auto-tensioners described in these publications provide a one-way clutch between a viscous damper and a swinging member (Japanese Patent Application Laid-Open No. 63-167163), or provide a ratchet mechanism (Japanese Patent Application Laid-Open No. Hei 2-167163). Japanese Unexamined Patent Publication (Kokai) No. 2-80839, Japanese Utility Model Laid-Open Publication No. 2-16846) and a damper device which incorporates a check valve and functions only in one direction.
No. 252, No. 3-24346, Japanese Utility Model Application Laid-Open No. 2-9
No. 8243), a damper device provided with an inclined surface for facilitating the flow of a viscous fluid only in one direction is provided (see Japanese Utility Model Laid-Open Publication No.
No. 9349).

Further, Japanese Patent Application Laid-Open No. 62-274143,
Japanese Utility Model Application Publication No. Sho 60-52458 discloses a structure in which a swinging member and a damper device are separately provided, and each of them is separately attached to a front surface of a cylinder block of an engine to form an auto tensioner. FIG. 7 shows an example of such an auto tensioner.

A swing member 10 supporting the pulley 5 is pivotally supported by a shaft 11 on the front surface of the cylinder block or the like. The cylinder 13 constituting the damper device 12 is fixed to the front surface of the cylinder block or the like separately from the swing member 10,
The hollow piston 14 can be displaced in the viscous fluid sealed in the cylinder 13. A compression spring 15 is provided between one end face of the piston 14 and a rear end face of the cylinder 13, and a base end of a push rod 16 is connected to the other end face. The tip of the push rod 16 abuts against a part of the rocking member 10 so that the rocking member 10
In addition, the elastic force of the compression spring 15 can be transmitted. Therefore, the pulley 5 is pressed against the belt 1 based on the elasticity of the compression spring 15. In addition, the actual opening 60-5245
As described in Japanese Patent Publication No. 8 (Kokai) No. 8, in addition to the compression spring 15 in the damper device 12, a spring may be provided on the swinging member 10.

On the other hand, a pair of chambers 17, 18 existing on both sides of the piston 14 communicate with each other via an oil passage 19 provided at the center between the piston 14 and the push rod 16. A check valve 20 is provided at the open end of the oil passage 19 and opens only when a viscous fluid flows toward the chamber 17 in which the compression spring 15 is provided.

In the case of the auto tensioner shown in FIG. 7, the push rod 16 is rapidly displaced in the protruding direction (upward direction in FIG. 7), and gradually displaced in the retracting direction (downward direction in FIG. 7). Therefore, when the belt 1 is slackened, the pulley 5 is quickly followed, and when the belt 1 is taut, the pulley 5 is held down without being retracted.

However, the auto-tensioners described in the above publications have the following problems.

That is, in the case of the conventional structure described in JP-A-58-65357 and JP-A-63-180759, since the pulley 5 can be displaced only slowly in any direction, if the belt is slackened. In some cases, the pulley 5 cannot follow this, and the belt tension temporarily drops.

The above-mentioned JP-A-63-167163, JP-A-2-72252, JP-A-2-80839, JP-A-3-24346 and JP-A-2-16846.
In the case of the auto-tensioners described in Japanese Patent Application Laid-Open Nos. 2-98243, 4-39349, etc., the one-way clutch suffers from fretting wear, resulting in insufficient durability (Japanese Patent Application Laid-Open No. 167163), the internal structure is complicated, the production is difficult, and the production cost increases (Japanese Patent Laid-Open No.
-72252, 2-80839 and 3-
No. 24346, Japanese Utility Model Application Laid-Open No. 2-16846,
JP-A-98243), the characteristics tend to change over time due to wear of parts, and even if the belt is slackened, the resistance of the viscous fluid is somewhat affected. -72252, 3-2
No. 4346, Japanese Utility Model Laid-Open No. 2-98243, 4-
39349).

In the case of the auto-tensioner shown in FIG. 7, the swing member 10 and the damper device 12 must be separately mounted on the front surface of the cylinder block or the like. The space is increased, the size of the engine incorporating the auto tensioner increases, and the weight increases.

On the other hand, Japanese Utility Model Laid-Open No. 2-56950 discloses that
In the structure shown in FIG. 7, the member provided with the shaft 11 and the cylinder 13 constituting the damper device 12 are integrated, and the pulley is pressed toward the belt by the elastic force of the torsion coil spring, thereby reducing the size. And a device designed to improve the assemblability. However, in the case of the structure described in this publication, the distance between the shaft 11 and the pivot supporting the pulley is short, and the displacement of the pulley pressing the belt cannot be increased.

An auto-tensioner that increases the amount of displacement of the pulley by increasing the distance between the shaft 11 and the pivot, and presses the pulley toward the belt by the elastic force of the torsion coil spring is disclosed, for example, in Japanese Unexamined Utility Model Publication No. 2-54946. However, in the case of this conventional structure, the belt is not completely stabilized because the pulley is prevented from moving simply by frictional resistance or internal loss of rubber. It is.

The inventor of the present invention has previously devised an auto-tensioner having a structure as shown in FIG. 8 as an auto-tensioner for solving any of the above-mentioned problems (Japanese Patent Application No. 4-67543).
issue). The auto-tensioner according to the present invention includes a fixed member 21, a fixed shaft 22 provided on the fixed member 21,
A swinging member 23 whose base end is rotatably supported around the fixed shaft 22, a pivot 25 provided at a distal end of the swinging member 23 and parallel to the fixed shaft 22, The pulley 24 is rotatably supported around the periphery 25, and a pair of locking portions 28 a and 28 b are provided at both ends of the coil portion 27. The coil portion 27 is arranged around the fixed shaft 22, By locking the pair of locking portions 28a and 28b into a locking hole 29b provided in the fixed member 21 and a locking hole 29a provided in the rocking member 23, respectively, A torsion coil spring 26 for applying elastic force in a direction of pressing the pulley 24 toward the belt 35, and a base end thereof supported by a fixed arm 30 provided on the fixed member 21, and provided on the rocking member 23. Receiving block fitted to the swinging arm piece 32 And a damper device 31 are opposed to the tip 3.

The damper device 31 includes a cylinder cylinder in which a viscous fluid is sealed, a piston fitted in the cylinder cylinder so as to be displaceable in the axial direction, and a piston cylinder and a cylinder cylinder. A spring that biases the piston in one direction, a plunger 34 that increases the amount of projection from the cylinder cylinder with the displacement of the piston based on the elasticity of the spring, and both ends of the piston in the axial direction. It has a passage that connects the surfaces, and a check valve that opens and closes this passage. The check valve has a function of closing only when the piston is displaced against the elasticity of the spring. The fixed shaft 22 is connected to the pulley 24
Exists in the diametrical outer side of the outer peripheral surface.

In the state of use of the auto-tensioner of the prior art constructed as described above, the swing member 23 swings based on the elasticity of the torsion coil spring 26, and the swing member 23
Pulley 24 rotatably supported by a pivot 25 at the distal end of the pulley
Is elastically pressed toward the belt 35. When the pulley 24 is pressed against the belt 35, the swing of the swing member 23 is limited. For this reason, the plunger 34 abuts with the receiving block 33 with the displacement of the piston constituting the damper device 31 supported by the fixed-side arm 30, and the tip of the plunger 34 comes into contact with the receiving block 33. The damper device 31 is pressed by the elastic force of the spring constituting the damper device 31.

When the belt 35 is loosened from this state, the swing member 23 swings based on the elasticity of the torsion coil spring 26,
The pulley 24 follows the movement of the belt 35. At this time, since the displacement of the plunger 34 is slightly delayed, the tip of the plunger 34 is separated from the receiving block 33. Therefore, when the belt 35 is loosened, the damper device 31 does not cause any resistance to rotating the swinging member 23 so that the pulley 24 follows the movement of the belt 35, and the pulley 24 Is quickly followed to prevent the tension of the belt 35 from decreasing. Due to the elastic force of the spring, the plunger 34 protrudes from the cylinder until the tip of the plunger 34 abuts against the receiving block 33 with a slight delay from the movement of the swing member 23. As described above, when the plunger 34 is pushed out of the cylinder based on the elasticity of the spring, since the check valve in the damper device 31 is opened, the displacement of the piston and the plunger 34 is performed relatively quickly, and the displacement is extremely short. After that, the tip of the plunger 34 abuts on the receiving block 33.

Conversely, when the tension of the belt 35 increases, the swing member 23 tends to rotate against the elasticity of the torsion coil spring 26. In this state, the receiving block 33
Is pressed against the tip of the plunger 34, so that the plunger 34
Must be pushed into the cylinder against the elasticity of the spring. At this time, since the check valve of the damper device 31 is closed, the displacement of the piston and the plunger is performed only slowly. As a result, the displacement of the pulley 24 supported by the swing member 23 is also performed only slowly by the operation of the damper device 31, and the belt 35
Is suppressed by the pulley 24, and the vibration of the belt 35 does not grow.

[0022]

SUMMARY OF THE INVENTION The auto-tensioner according to the present invention, which is constructed and operates as described above, eliminates various inconveniences of the auto-tensioners described in each of the above-mentioned publications, and provides durability and reliability. Thus, it is possible to always maintain the belt tension optimally by improving the performance and followability of the belt movement. By the way, since the installation space of the auto tensioner is narrow, it is preferable to make the auto tensioner as small and lightweight as possible. In view of this point, the auto-tensioner according to the present invention enables further reduction in size and weight while maintaining the effects of the above-described auto-tensioner according to the present invention.

[0023]

According to the present invention, there is provided an auto-tensioner comprising a fixed shaft provided on a base to which the auto-tensioner is to be mounted, and a swing member having a base end rotatably supported around the fixed shaft. A pivot provided parallel to the fixed axis, a pulley rotatably supported around the pivot, and a pair of locking portions provided at both ends of the coil portion. The pulley is attached to the rocking member by positioning the coil portion around the fixed shaft and locking the pair of locking portions to the base and the rocking member, respectively. A torsion coil spring that provides elasticity in the direction of pressing toward, and one end of the torsion-side arm piece provided on the oscillating member is brought into contact with the other end, and the other end is fixed to the fixed-side projection piece fixed to the base. And a damper device in contact therewith.

The damper device includes a cylinder cylinder having a viscous fluid sealed therein, and a cylinder cylinder having:
A piston fitted in the cylinder cylinder so as to be relatively displaceable in the axial direction, a spring provided between the piston and the cylinder cylinder to bias the piston in one direction, and a spring based on the elastic force of the spring. A plunger that increases the amount of protrusion of the piston from the cylinder cylinder with the relative displacement of the piston with respect to the cylinder cylinder, a passage communicating the axial end faces of the piston with each other, and a check valve that opens and closes the passage. ing. The check valve has a function to close only when the piston is displaced relative to the cylinder cylinder against the elasticity of the spring. In addition, the fixed shaft exists outside the outer peripheral surface of the pulley in the diameter direction.

[0025]

The function of pressing the belt, the function of following the movement of the belt, and the function of suppressing vibration of the auto tensioner of the present invention configured as described above are almost the same as those of the above-described auto tensioner according to the present invention. It is. In particular, in the auto-tensioner of the present invention, the fixing member in the auto-tensioner of the present invention is omitted, so that the size and weight can be further reduced.

[0026]

1 to 4 show a first embodiment of the present invention. The swinging member 23a has a cylindrical portion 36 at a base end (the lower end in FIGS. 1 and 2), and is supported on a base 38 such as the front surface of a cylinder block by a bolt 37 which is a fixed shaft inserted through the cylindrical portion 36. Is done. That is, the cylindrical portion 36 formed at the base end of the swinging member 23a is fitted around the bolt 37 as a fixed shaft via a sliding bearing 39. The rocking member 23a is swingably supported on the base 38 by screwing the bolt 37 into a screw hole 40 formed in the base 38. The swing of the swing member 23a is smoothly performed by the presence of the slide bearing 39.

The tip of the swinging member 23a (FIG. 1)
2), a circular convex portion 41 forming a pivot parallel to the bolt 37 is formed on the inner ring 4 of a rolling bearing 42 for rotatably supporting the pulley 24.
3 is fixed. That is, after passing the bolt 44 through the center hole of the inner ring 43 and the seat plate 45, the nut 46 is tightened,
By suppressing the periphery of the center hole of the inner ring 43, the inner ring 43 is prevented from falling off from the convex portion 41, and the pulley 2
4 is rotatably supported by the tip of the swing member 23a. In this state, the bolt 37 serving as the fixed shaft is located diametrically outside the outer peripheral surface of the pulley 24. In addition, as a method of fixing the inner ring 43 to the swinging member 23a,
In addition to screwing the bolt 44 and the nut 46 together, the inner ring 43 may be press-fitted into the swing member 23a, or the inner ring 43 and the swing member 23a may be integrally formed.

Around the cylindrical portion 36, a coil portion 27 of the torsion coil spring 26 is arranged. The torsion coil spring 26 has a pair of locking portions 2 at both ends of the coil portion 27.
8a and 28b, and one locking portion 28a is inserted into a locking hole 47a formed in the swinging member 23a.
And the other locking portion 28b is locked in a locking hole 47b formed in the base 38. The torsion coil spring 26 imparts elasticity to the swing member 23a so as to rotate clockwise in FIG. 1 around the bolt 37. The locking portion 28b is
In addition to the locking in the locking hole 47b, the locking may be performed by a locking piece such as a locking groove or a pin provided in the base 38.

The projection 41 is formed by a part of the swing member 23a.
The swing arm 32a is provided at a position apart from the swing arm 32a, and the damper device 31 is provided in a concave portion 49 formed in the swing arm 32a.
a. On the other hand, a part of the base 38, which is away from the bolt 37,
8 is provided, and the end face of the projecting piece 48 is provided with the damper device 31.
The other end of “a” is opposed.

As shown in FIGS. 3 and 4, the damper device 31a encloses a viscous fluid such as silicon oil in a cylinder 50 and a piston 51 in the cylinder 50 in an axial direction (see FIG. 3). (Up and down directions of 3-4). A compression spring 52 is provided between the piston 51 and the rear end surface of the cylinder cylinder 50, and presses the piston 51 in a direction protruding from the cylinder cylinder 50. Further, the base end of the plunger 53 is in contact with the piston 51. Therefore, the compression spring 52
When the piston 51 is displaced relative to the cylinder cylinder 50 based on the elasticity of the plunger 53, the amount of protrusion of the plunger 53 from the cylinder cylinder 50 increases.

A circular hole 54 is formed in the center of the piston 51, and constitutes a passage for communicating both axial end surfaces of the piston 51. The ball 56 is pressed against the open end of the circular hole 54 by the elastic force of the second compression spring 57 to open and close the passage to form a check valve 58 of a ball valve type. The check valve 58 is closed only when the piston 51 is displaced against the elasticity of the compression spring 52. The notches 55, 55 formed on the opening edge of the piston 51 are provided with a minute gap existing between the outer peripheral surface of the piston 51 and the inner peripheral surface of the cylinder cylinder 50, and the inside of the piston 51. To communicate with the space 60 to be used.

In this embodiment, the damper device 31 is used.
a, the plunger 53 side of the damper device 31a is fitted in a recess 49 provided in the swing arm 32a, and the distal end of the cylinder cylinder 50 is attached to the base. The protruding piece 48 provided on the surface 38 is in contact with the protruding piece 48. For this reason, the end of the cylinder 50 is moved with the swing of the swing member 23a.
It is displaced from the recess 49 in the protruding direction. That is, since the damper device 31a allows the relative displacement of the piston 51 with respect to the cylinder cylinder 50, when the plunger 53 side is fitted in the concave portion 49 as shown in FIGS. Accordingly, the cylinder cylinder 50 is displaced, and the amount of projection of the cylinder cylinder 50 from the recess 49 changes. still,
3 and 4, reference numeral 59 denotes a sealing material.

The function of pressing the belt, the function of following the movement of the belt, and the function of suppressing the swing of the automatic tensioner of the present invention configured as described above are the same as those of the above-described auto-tensioner according to the present invention. It is almost the same as That is, in the use condition of the auto tensioner of the present invention,
The swing member 23a swings based on the elasticity of the torsion coil spring 26, and the pulley 24 rotatably supported by the tip of the swing member 23a is elastically pressed toward the belt 35. When the pulley 24 is pressed against the belt 35, the swing of the swing member 23a is limited.
The swing-side arm piece 32a provided at a does not move any further. Therefore, when the piston 51 constituting the damper device 31a supported by the swing arm 32a of the swing member 23a is relatively displaced with respect to the cylinder cylinder 50 by the elastic force of the compression spring 52, as shown in FIG. Recess 4 of cylinder cylinder 50
The protrusion from the cylinder 9 is increased, and the tip of the cylinder 50 is pressed against the protrusion 48 of the base 38.

When the belt 35 is loosened from this state, the swinging member 23a swings clockwise in FIG. 1 around the bolt 37 based on the elasticity of the torsion coil spring 26, and moves the pulley 24 to move the belt 35. To follow. At this time, since the displacement of the cylinder 50 is slightly delayed, the tip of the cylinder 50 is separated from the projecting piece 48. Therefore, when the belt 35 is slackened, when the swing member 23a is rotated to make the pulley 24 follow the movement of the belt 35,
The damper device 31a does not cause any resistance, and causes the pulley 24 to quickly follow the movement of the belt 35 to prevent the tension of the belt 35 from decreasing. Further, since the distance between the bolt 37 serving as the rotation center of the swing member 23a and the rotation center of the pulley 24 is sufficiently large, the displacement of the pulley 24 can be sufficiently large, and the slack of the belt 35 is large. In this case, this slack can be sufficiently eliminated.

Due to the elasticity of the compression spring 52, the cylinder cylinder 50 is slightly recessed from the movement of the swinging member 23a until the tip of the cylinder cylinder 50 abuts against the projection 48.
Protruding from. Thus, when pushing out the cylinder cylinder 50 based on the elasticity of the compression spring 52, the damper device 31a
Is opened by displacing the ball 56 against the elasticity of the compression spring 57, the displacement of the cylinder cylinder 50 is performed relatively quickly, and after a very short time, the cylinder cylinder 50 is displaced. The tip of 50 abuts the protruding piece 48.

Conversely, when the tension of the belt 35 increases, the swinging member 23a tends to swing counterclockwise in FIG. 1 around the bolt 37 against the elasticity of the torsion coil spring 26. In this state, since the bottom surface of the concave portion 49 is pressed against the tip of the plunger 53, the plunger 53 and the piston 51 are moved by the compression spring 52 in order to rotate the swing member 23a. In opposition, it must be pushed into the cylinder cylinder 50.

At this time, the ball 56 constituting the check valve 58 incorporated in the damper device 31a is pressed against the opening of the circular hole 54, and the passage communicating with both sides of the piston 51 is closed. For this reason, the movement of the viscous fluid on both sides of the piston 51 is caused by the outer peripheral surface of the piston 51 and the cylinder cylinder 5.
Only through a minute gap existing between the inner peripheral surface of
Done. Therefore, the displacement of the piston 51 and the plunger 53 is performed only slowly. As a result, the displacement of the pulley 24 supported by the swing member 23a is also performed only slowly by the operation of the damper device 31a, and the belt 35 is suppressed by the pulley 24, and the vibration of the belt 35 grows. You won't have to.

The operation of pressing the pulley 24 against the belt 35 and pressing the belt 35, the operation of causing the pulley 24 to follow the movement of the belt 35, and the operation of suppressing the vibration of the belt 35 are described above. This is almost the same as the auto-tensioner according to the present invention. However, in the auto-tensioner according to the present invention, since the fixing member 21 (FIG. 8) constituting the auto-tensioner according to the present invention is omitted, the auto-tensioner is not used. The whole can be made small and lightweight. As a result, installation in a narrow installation space becomes possible.

FIG. 5 shows a second embodiment of the present invention. In the case of this embodiment, contrary to the case of the above-described first embodiment, the cylinder tube 50 constituting the damper device 31a is supported in the concave portion 49 of the swinging arm 32a , and the projection 48 (see FIG.
The plunger 53 can be freely abutted on the front end of the light source.
Therefore, the plunger 5 is moved with the swing of the swing member 23a.
The protrusion amount of No. 3 changes. Other configurations and operations are the same as those of the first embodiment.

[0040]

[Effects of the Invention] The auto tensioner of the present invention is constructed and operates as described above, so that it can be manufactured at a small size, light weight, and inexpensively, despite the structure having excellent durability and reliability. There is no bulk and the belt tension can always be kept in an optimal state. Further, since the displacement amount of the pulley can be increased, the pulley can sufficiently follow the movement of the belt even when the slack amount of the belt is large.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is an enlarged cross-sectional view of the damper device shown in a state where the cylinder tube is retracted.

FIG. 4 is a cross-sectional view similar to FIG. 3, showing a state in which a cylinder cylinder is projected.

FIG. 5 is a sectional view similar to FIG. 3, showing a second embodiment of the present invention;

FIG. 6 is a front view showing an engine belt drive device provided with an auto tensioner.

FIG. 7 is a sectional view showing an example of a conventional structure.

FIG. 8 is a cross-sectional view showing the present invention.

[Explanation of symbols]

Reference Signs List 1 belt 2 drive pulley 3 driven pulley 4 guide pulley or driven pulley 5 pulley 6 pivot 7 swinging member 8 spring 9 bracket 10 swinging member 11 shaft 12 damper device 13 cylinder 14 piston 15 compression spring 16 push rod 17, 18 chamber Reference Signs List 19 oil passage 20 check valve 21 fixing member 22 fixed shaft 23, 23a swinging member 24 pulley 25 pivot 26 torsion coil spring 27 coil portion 28a, 28b locking portion 29a, 29b locking hole 30 fixed arm piece 31, 31a Damper device 32, 32a Swing-side arm piece 33 Receiving block 34 Plunger 35 Belt 36 Cylindrical part 37 Bolt 38 Base 39 Sliding bearing 40 Screw hole 41 Convex part 42 Rolling bearing 43 Inner ring 44 Bolt 45 Seat plate 46 Nut 47a, 47b Stop hole 48 Protrusion piece 49 Recess 50 Cylinder 51 piston 52 compression spring 53 the plunger 54 circular hole 55 notch 56 ball 57 second compression spring 58 check valve 59 sealing material 60 space 61 sliding bearing

Claims (1)

(57) [Scope of request for utility model registration] 1. A fixed shaft provided on a base to which an auto-tensioner is to be mounted, a swing member having a base end rotatably supported around the fixed shaft, and a swing member provided at a distal end of the swing member. A pivot parallel to the fixed shaft, a pulley rotatably supported around the pivot, and a pair of locking portions provided at both ends of the coil portion. By disposing the pair of locking portions around the base and the swinging member, respectively,
A torsion coil spring for applying an elastic force to the swing member in a direction of pressing the pulley toward the belt, and one end of the torsion coil spring provided on the swing side arm piece provided on the swing member, and fixed to the base. A damper device having the other end in contact with the fixed-side protruding piece. The damper device has a cylinder cylinder filled with a viscous fluid therein, and an axial direction inside the cylinder cylinder with respect to the cylinder cylinder. A piston which is fitted between the piston and the cylinder cylinder, the spring is provided between the piston and the cylinder cylinder, and urges the piston in one direction. Along with the displacement, a plunger that increases the amount of protrusion from the cylinder cylinder, a passage communicating the two axial end surfaces of the piston, and a check valve that opens and closes this passage are provided. Above Tons has only close function when displaced relative to the cylinder tube against the elastic force of the spring, and, auto-tensioner said fixed shaft is present in the diameter direction outer side than the outer peripheral surface of the pulley.