JPH0687758U - Auto tensioner - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a structure that does not occupy a large installation space and reliably prevents the belt from loosening. [Structure] A base end portion of a swinging member 23a is swingably supported by a fixed shaft 37, and a pulley 2 is attached to a tip end portion of the swinging member 23a.
4 is rotatably supported. In order to press the pulley 24 against the belt 35 by the torsion coil spring 26, the swing member 23
The elastic force in the rotational direction is given to a. A damper device 31a is provided between the rocking side arm piece 32a provided on the rocking member 23a and the projecting piece fixed to the base body. When the swinging member 23a is rotated by the elastic force of the torsion coil spring 26, the damper device 31
The lower end of a and the protruding piece supported by the base are separated. Therefore, the pulley 24 is displaced quickly. When rotating in the opposite direction, the rocking side arm piece 32a pushes the upper end of the damper device 31a. In this state, the displacement of the pulley 24 becomes slow due to the action of the damper device 31a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The auto tensioner according to the present invention applies proper tension to a timing belt of an automobile engine or a belt for driving an auxiliary machine such as an alternator or a compressor (hereinafter, these belts are simply referred to as "belt"). Use to do.

[0002]

[Prior art]

 Since a camshaft of an OHC type engine or a DOHC type engine is rotationally driven in synchronization with a crankshaft, a drive device using a belt 1 as shown in FIG. 6 is widely used. In FIG. 6, 2 is a drive pulley which is rotationally driven by the crankshaft of the engine, 3 is a driven pulley fixed to the end of the camshaft, 4 and 4 are for guiding the belt 1, or water. Guide pulleys or driven pulleys for driving auxiliary machines such as pumps and the like, and 5 are pulleys for giving proper tension to the belt 1.

The pulley 5 is pivotally supported by a swing member 7 that swings around a pivot 6. A spring 8 is provided at the end of the bracket 9 fixed to the swinging member 7, and the pulley 5 is elastically pressed toward the belt 1 so that the belt 1 and the like due to temperature change and the like can be prevented. The tension of the belt 1 is always kept constant irrespective of dimensional changes and vibrations associated with engine operation.

By the way, in addition to the function of applying tension to the belt 1, the automatic tensioner is required to have a function of holding down the belt 1. That is, in the camshaft drive device shown in FIG. 6, when the drive pulley 2 is rotated, a part of the belt 1 located between the pulleys 2 to 5 is in a direction perpendicular to the traveling direction. In addition, there is a tendency to vibrate. If this vibration is allowed as it is, the amplitude of the vibration becomes large (vibration grows), abnormal vibration occurs in the drive part by the belt 1, or in the case of a toothed belt, so-called tooth skipping occurs. Etc. causes problems.

Therefore, conventionally, for example, as described in JP-A-58-65357 and JP-A-63-180759, a damper device is incorporated in an auto tensioner, and the belt 1 is mounted by the damper device. Something is being held down. In order to prevent the belt 1 from slackening more reliably, the pulley 5 is swiftly followed when the belt 1 is slackened, and when the belt 1 is strained, the pulley 5 is not retracted. An automatic tensioner that holds down the belt 1 is also disclosed in, for example, JP-A-63-167163, JP-A-2-72252, JP-A-2-80839, JP-A-3-2346, and JP-A-2-16846. , No. 2-98243, No. 4-39349, etc., are conventionally known.

The auto tensioner described in each of these publications is provided with a one-way clutch between the viscous damper and the oscillating member (Japanese Patent Laid-Open No. 63-167163) or a ratchet mechanism (Japanese Laid-Open Patent Publication No. HEI-2). No. 80839, Japanese Utility Model Laid-Open No. 2-16846), a checker valve is incorporated to provide a damper device that functions only in one direction (Japanese Patent Laid-Open Nos. 2-72252, 3-24346, and Japanese Utility Model Laid-Open No. No. 98243), a damper device having an inclined surface for facilitating the flow of a viscous fluid in only one direction is provided (Japanese Utility Model Laid-Open No. 4-39349).

Further, in Japanese Patent Laid-Open No. 62-274143 and Japanese Utility Model Laid-Open No. 60-52458, a rocking member and a damper device are provided separately, and they are separately mounted on the front surface of a cylinder block of an engine or the like. The structure of an auto tensioner is described. FIG. 7 shows an example of such an auto tensioner.

The swinging 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, and the hollow piston 14 is displaceable in the viscous fluid enclosed in the cylinder 13. . A compression spring 15 is provided between one end surface of the piston 14 and the rear end surface of the cylinder 13, and a base end portion of a push rod 16 is connected to the other end surface. The tip of the push rod 16 abuts against a part of the swing member 10 so that the resilience of the compression spring 15 can be transmitted to the swing member 10. Therefore, the pulley 5 is pressed against the belt 1 based on the elasticity of the compression spring 15. Incidentally, as described in Japanese Utility Model Laid-Open No. 60-52458, in addition to the compression spring 15 in the damper device 12, a spring may be provided in the swing member 10.

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

In the case of the auto-tensioner shown in FIG. 7 configured as described above, the push rod 16 is rapidly displaced in the projecting direction (upward direction in FIG. 7) and is retracted in the retracting direction (downward direction). Since it changes only slowly, when the belt 1 becomes loose, the pulley 5 is swiftly followed, and when the belt 1 is tensioned, the belt 1 is suppressed without retracting the pulley.

However, each of the auto tensioners described in the above publications has 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, the belt is loose. In this case, the pulley 5 cannot follow this and the tension of the belt may temporarily decrease.

Further, the above-mentioned JP-A-63-167163, JP-A-2-72252, JP-A-2-80839, JP-A-3-24346, JP-A-2-16846 and JP-A-2-98243. In the case of the auto tensioner described in Japanese Patent Laid-Open No. 4-39349, etc., the one-way clutch has fretting wear, resulting in insufficient durability (Japanese Patent Laid-Open No. 63-167163), and an internal structure. It is complicated and difficult to manufacture, and the manufacturing cost is high (Japanese Patent Laid-Open No. 2-72252, No. 2-80839, No. 3-24346, No. 2-16846, No. 2-98243). ), The characteristics tend to change over time due to wear of parts, and even if the belt is loosened, some resistance from the viscous fluid is received, so the followability of the pulley is not always sufficient. (JP-A-2-72252, JP-A-3-24346, JP-A-2-98243 and JP-A-4-39349).

Further, in the case of the auto tensioner shown in FIG. 7, since it is necessary to separately mount the swing member 10 and the damper device 12 on the front surface of the cylinder block or the like, not only is the installation work troublesome, but also the installation work is difficult. The space increases, and the engine incorporating this autotensioner becomes larger and heavier.

On the other hand, in Japanese Utility Model Laid-Open No. 2-56950, in the structure shown in FIG. 7, a member provided with a shaft 11 and a cylinder 13 constituting a damper device 12 are integrated, and a torsion coil spring is used. By pushing the pulley toward the belt by the elasticity of, the device is downsized and the assembling is improved. However, in the structure described in this publication, the distance between the shaft 11 and the pivot that pivotally supports the pulley is short, and the displacement of the pulley that presses the belt cannot be increased.

By increasing the distance between the shaft 11 and the pivot, the displacement amount of the pulley is increased, and as an autotensioner that presses the pulley toward the belt by the elastic force of the torsion coil spring, for example, the actual flattening 2- A structure as described in Japanese Patent No. 54946 is known, but in the case of this conventional structure, since the structure for simply preventing the pulley from being caused by frictional resistance and internal loss of rubber, the belt has an anti-sway effect. Incomplete.

The inventor of the present invention has previously devised an autotensioner having a structure as shown in FIG. 8 as an autotensioner that solves all of the above problems (Japanese Patent Application No. 4-67543). The autotensioner according to the present invention includes a fixed member 21, a fixed shaft 22 provided on the fixed member 21, and a swing member 23 having a base end rotatably supported around the fixed shaft 22. A pivot 25 parallel to the fixed shaft 22 provided at the tip of the swinging member 23; a pulley 24 rotatably supported around the pivot 25; Locking holes 28a, 28b are provided, the coil portion 27 is arranged around the fixed shaft 22, and the pair of locking portions 28a, 28b is provided in the fixing member 21. 29b and a locking hole 29a provided in the rocking member 23, respectively, and a torsion coil spring 26 that gives the rocking member 23 elasticity in a direction of pressing the pulley 24 toward the belt 35. , On the fixing member 21 The fixed end arm piece 30 supports the base end portion thereof, and the receiving block 33 fitted to the swinging side arm piece 32 provided on the swinging member 23 is provided with a damper device 31 with its tip end facing. I have it.

The damper device 31 includes a cylinder cylinder in which a viscous fluid is sealed, a piston displaceably fitted in the cylinder cylinder in the axial direction, the piston and the cylinder cylinder. A spring for urging the piston in one direction, a plunger 34 that increases the amount of protrusion from the cylinder cylinder with displacement of the piston due to the elastic force of the spring, and a shaft of the piston. A passage connecting both end faces in the direction and a check valve opening / closing this passage are provided. The check valve has a function of closing only when the piston is displaced against the elastic force of the spring. At the same time, the fixed shaft 22 is located diametrically outside the outer peripheral surface of the pulley 24.

In the use state of the auto-tensioner of the prior invention configured as described above, the swinging member 23 swings based on the elasticity of the torsion coil spring 26, and the swinging member 23 has a front end portion. The pulley 24, which is rotatably supported by the pivot shaft 25, is elastically pressed toward the belt 35. By pressing the pulley 24 against the belt 35, the rocking of the rocking member 23 is restricted. Therefore, the plunger 34 abuts the receiving block 33 with the displacement of the piston that constitutes the damper device 31 supported by the fixed side arm piece 30, and the tip end of the plunger 34 contacts the receiving block 33. The elastic force of the spring forming the damper device 31 causes the damper device 31 to be pressed.

When the belt 35 loosens from this state, the rocking member 23 rocks based on the elasticity of the torsion coil spring 26, causing the pulley 24 to follow the movement of the belt 35. At this time, since the displacement of the plunger 34 is 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 become a resistance against rotating the swinging member 23 so that the pulley 24 follows the movement of the belt 35. The tension of the belt 35 is prevented from decreasing by promptly following the movement of the belt 35. Due to the elastic force of the spring, the plunger 34 is slightly delayed from the movement of the swinging member 23, and protrudes from the cylinder until its tip end abuts against the receiving block 33. As described above, when the plunger 34 is pushed out from the cylinder based on the elasticity of the spring, the check valve in the damper device 31 is opened, so that the displacement of the piston and the plunger 34 is performed relatively quickly, which is extremely short. After a lapse of time, the tip of the plunger 34 abuts the receiving block 33.

On the contrary, 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. Therefore, in order to rotate the swinging member 23, the plunger 34 must be pushed into the cylinder against the elastic force of the spring. I have to. At this time, since the check valve of the damper device 31 is closed, the displacement of the piston and the plunger can be performed only slowly. As a result, the displacement of the pulley 24 supported by the swinging member 23 is only slowly performed by the action of the damper device 31, the belt 35 is suppressed by the pulley 24, and the vibration of the belt 35 grows. There is nothing to do.

[0022]

[Problems to be solved by the device]

 The autotensioner according to the prior invention, which is constructed and operates as described above, eliminates all of the various inconveniences of the autotensioners described in the above-mentioned publications, and has durability, reliability, and followability to the movement of the belt. The belt tension can be maintained optimally at all times. By the way, since the installation space of the auto tensioner is small, it is preferable to make it as small and lightweight as possible. In view of this point, the autotensioner of the present invention enables further reduction in size and weight while maintaining the effect of the above-described autotensioner according to the previous invention.

[0023]

[Means for solving the problem]

 The autotensioner of the present invention comprises a fixed shaft provided on a base body to which the autotensioner is attached, a swinging member whose base end is rotatably supported around the fixed shaft, and a tip end of the swinging member. A pivot shaft parallel to the fixed shaft, a pulley rotatably supported around the pivot shaft, and a pair of locking parts at both ends of the coil part. The elastic member is disposed around the fixed shaft, and the pair of locking portions are locked to the base body and the rocking member respectively, so that the rocking member is provided with elastic force in the direction of pressing the pulley toward the belt. A torsion coil spring to be imparted and a damper device in which one end of the swing side arm piece provided on the swing member is brought into contact with the fixed side projection piece fixed to the base body and the other end thereof is brought into contact with the swing side arm piece. Prepare

This damper device includes a cylinder cylinder in which a viscous fluid is enclosed, a piston fitted inside the cylinder cylinder so as to be relatively displaceable in the axial direction relative to the cylinder cylinder, and A spring that is provided between the piston and the cylinder cylinder and biases the piston in one direction, and the relative displacement of the piston with respect to the cylinder cylinder due to the elastic force of the spring causes the protrusion from the cylinder cylinder. It is provided with a plunger for increasing the amount, a passage for connecting both axial end faces of the piston, and a check valve for opening and closing this passage. The check valve has a function of closing only when the piston is displaced relative to the cylinder cylinder against the elastic force of the spring. In addition, the fixed shaft exists outside the outer peripheral surface of the pulley in the diametrical direction.

[0025]

[Action]

 The action of pressing the belt, the action of following the movement of the belt, and the action of suppressing the vibration of the autotensioner of the present invention configured as described above are substantially the same as those of the autotensioner according to the above-mentioned prior invention. In particular, in the autotensioner of the present invention, since the fixing member in the autotensioner of the previous invention is omitted, it is possible to further reduce the size and weight.

[0026]

【Example】

 1 to 4 show a first embodiment of the present invention. The oscillating member 23a has a cylindrical portion 36 at the base end portion (lower end portion in FIGS. 1 and 2), and is supported by a base body 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. To be done. That is, the cylindrical portion 36 formed at the base end portion of the swinging member 23a is externally fitted around the circumference of the bolt 37 which is the fixed shaft via the slide bearing 39. The swing member 23a is swingably supported by the base body 38 by screwing the bolt 37 into the screw hole 40 formed in the base body 38. The swinging of the swinging member 23a is smoothly performed by the existence of the slide bearing 39.

Further, a circular convex portion 41 forming a pivot parallel to the bolt 37 is formed at the tip end portion (upper end portion in FIGS. 1 and 2) of the swinging member 23 a. The inner ring 43 of the rolling bearing 42 for rotatably supporting the pulley 24 is fixed. That is, the bolt 44 is passed through the center hole of the inner ring 43 and the seat plate 45, and then the nut 46 is tightened to hold down the periphery of the center hole of the inner ring 43, so that the inner ring 43 comes off from the convex portion 41. And the pulley 24 is rotatably supported on the tip of the swing member 23a. In this state, the bolt 37, which is the fixed shaft, is located radially outside the outer peripheral surface of the pulley 24. 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 described above, the inner ring 43 is press-fitted into the swinging member 23a or swings with the inner ring 43. It is conceivable to integrally form the moving member 23a.

A coil portion 27 of the torsion coil spring 26 is arranged around the cylindrical portion 36. The torsion coil spring 26 is formed by providing a pair of locking portions 28a, 28b at both ends of the coil portion 27, and one of the locking portions 28a is a sliding bearing in a locking hole 47a formed in the swing member 23a. It is inserted through 61, and the other locking portion 28b is locked in the locking hole 47b formed in the base body 38. The torsion coil spring 26 gives the swinging member 23a an elastic force to rotate in the clockwise direction in FIG. 1 about the bolt 37. When the locking portion 28b is locked to the base 38, it may be locked to the locking hole 47b, or may be locked by a locking groove or a locking piece such as a pin provided on the base 38.

A swing side arm piece 32a is provided at a part of the swing member 23a away from the convex portion 41, and a damper device 31a is provided in a recess 49 formed in the swing side arm piece 32a. Is embedded inside. On the other hand, a protruding piece 48, which is a fixed side protruding piece, is provided at a position apart from the bolt 37 on a part of the base body 38, and the other end of the damper device 31a is opposed to the end surface of the protruding piece 48. ing.

As shown in FIGS. 3 to 4, the damper device 31 a encloses a viscous fluid such as silicone oil in the cylinder barrel 50, and the piston 51 in the axial direction in the cylinder barrel 50. It is fitted so that it can be displaced (vertical direction in FIGS. 3 and 4). A compression spring 52 is provided between the piston 51 and the rear end surface of the cylinder cylinder 50 to press the piston 51 in a direction projecting from the cylinder cylinder 50. Further, the base end of the plunger 53 is brought into contact with the piston 51. Therefore, when the piston 51 is displaced relative to the cylinder cylinder 50 based on the elasticity of the compression spring 52, 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 to form a passage that connects both axial end surfaces of the piston 51. The ball 56 is pressed against the opening end of the circular hole 54 by the elastic force of the second compression spring 57 to form the ball valve type check valve 58 that opens and closes the passage. The check valve 58 is closed only when the piston 51 is displaced against the elastic force of the compression spring 52. The notches 55, 55 formed at the opening edge of the piston 51 are formed on the inside of the piston 51 and a minute gap existing between the outer peripheral surface of the piston 51 and the inner peripheral surface of the cylinder cylinder 50. It is intended to communicate with the existing space 60.

In the present embodiment, in order to fit and support the damper device 31a in the swing side arm piece 32a, the plunger 53 side of the damper device 31a is provided in the swing side arm piece 32a. It is fitted in the portion 49, and the tip end portion of the cylinder cylinder 50 is brought into contact with the protruding piece 48 provided on the base body 38. Therefore, the end portion of the cylinder cylinder 50 is displaced in the protruding direction from the recess 49 as the swing member 23a swings. That is, since the damper device 31a freely displaces the piston 51 relative to the cylinder cylinder 50, when the plunger 53 side is fitted in the recess 49 as shown in FIGS. The cylinder cylinder 50 is displaced along with the displacement of the cylinder cylinder 50, and the amount of protrusion of the cylinder cylinder 50 from the recess 49 changes. In FIGS. 3 and 4, reference numeral 59 is a sealing material.

In the autotensioner of the present invention configured as described above, the action of pressing the belt, the action of following the movement of the belt, and the action of suppressing the swing are the same as those of the autotensioner according to the above-mentioned earlier invention. Is almost the same as. That is, when the autotensioner of the present invention is used, the swing member 23a swings due to the elasticity of the torsion coil spring 26, and the pulley rotatably supported at the tip of the swing member 23a. 24 is elastically pressed against the belt 35. By pressing the pulley 24 against the belt 35, the rocking of the rocking member 23a is restricted, and the rocking side arm piece 32a provided on the rocking member 23a is prevented from further displacement. Therefore, when the piston 51 constituting the damper device 31a supported by the swing side arm piece 32a of the swing member 23a is displaced relative to the cylinder cylinder 50 by the elasticity of the compression spring 52, as shown in FIG. The amount of protrusion of the cylinder cylinder 50 from the recess 49 increases, and the tip of the cylinder cylinder 50 is pressed against the projecting piece 48 of the base 38.

When the belt 35 loosens from this state, the swinging member 23 a swings clockwise around the bolt 37 in FIG. 1 based on the elastic force of the torsion coil spring 26, and the pulley 24 is moved toward the belt 35. Follow the movement. At this time, since the displacement of the cylinder cylinder 50 is delayed, the tip of the cylinder cylinder 50 and the protrusion 48 are separated from each other. Therefore, when the belt 35 is slackened, the damper device 31a does not resist the rotation of the swing member 23a so that the pulley 24 follows the movement of the belt 35. The movement of the belt 35 is quickly followed to prevent the tension of the belt 35 from decreasing. Further, since the distance between the bolt 37, which is the rotation center of the swinging member 23a, and the rotation center of the pulley 24 is sufficiently large, the amount of displacement of the pulley 24 can be made sufficiently large and the slack of the belt 35 can be prevented. Even if it is large, this slack can be fully eliminated.

Due to the elasticity of the compression spring 52, the cylinder cylinder 50 projects from the recess 49 until the tip of the cylinder cylinder 50 abuts against the protrusion 48, slightly behind the movement of the swinging member 23a. Thus, when the cylinder cylinder 50 is pushed out based on the elasticity of the compression spring 52, the check valve 58 in the damper device 31a opens by displacing the ball 56 against the elasticity of the compression spring 57. Therefore, the displacement of the cylinder cylinder 50 is performed relatively quickly, and after a very short time, the tip of the cylinder cylinder 50 collides with the protrusion 48.

On the contrary, 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 elastic force of the torsion coil spring 26. In this state, since the bottom surface of the recess 49 is pressed against the tip of the plunger 53, the plunger 53 and the piston 51 are moved by the elastic force of the compression spring 52 and the damper in order to rotate the swinging member 23a. It must be pushed into the cylinder barrel 50 against the resistance.

At this time, the ball 56 that constitutes the check valve 20 built in the damper device 31a is pressed against the opening of the circular hole 54, and the passage that connects both sides of the piston 51 is closed. Therefore, the movement of the viscous fluid on both sides of the piston 51 is carried out only through a minute gap existing between the outer peripheral surface of the piston 51 and the inner peripheral surface of the cylinder cylinder 50. Therefore, the displacement of the piston 51 and the plunger 53 can be performed only slowly. As a result, the displacement of the pulley 24 supported by the swinging member 23a is only slowly performed by the action of the damper device 31a, and the belt 35 is restrained by the pulley 24, and the vibration of the belt 35 is suppressed. It will never grow up.

The operation of pressing the pulley 24 against the belt 35 to press 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 as described above. It is almost the same as the auto tensioner according to the previous invention, but further, in the auto tensioner of the present invention, since the fixing member 21 (FIG. 8) constituting the auto tensioner according to the above invention is omitted, The entire auto tensioner can be made compact and lightweight. As a result, it can be installed in a narrow installation space.

Next, FIG. 5 shows a second embodiment of the present invention. In the case of the present embodiment, contrary to the case of the first embodiment described above, the cylinder cylinder 50 constituting the damper device 31a is supported in the recess 49 of the swing-side arm piece 32, and the tip end of the protrusion piece 48 is supported. The plunger 53 can be contacted freely. Therefore, the amount of protrusion of the plunger 53 changes as the swing member 23a swings. Other configurations and operations are similar to those of the above-described first embodiment.

[0040]

[Effect of device]

 Since the autotensioner of the present invention is constructed and operates as described above, it can be manufactured in a small size, a light weight, and at a low cost, and has a large installation space, despite the structure having excellent durability and reliability. The belt tension can always be kept in an optimum state. Further, since the amount of displacement of the pulley can be increased, the pulley can sufficiently follow the movement of this belt even when the amount of slack in the belt is large.

[Submission date] August 12, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

At this time, the ball 56 forming the check valve 58 built into 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. Therefore, the movement of the viscous fluid on both sides of the piston 51 is carried out only through a minute gap existing between the outer peripheral surface of the piston 51 and the inner peripheral surface of the cylinder cylinder 50. Therefore, the displacement of the piston 51 and the plunger 53 can be performed only slowly. As a result, the displacement of the pulley 24 supported by the swinging member 23a is only slowly performed by the action of the damper device 31a, and the belt 35 is restrained by the pulley 24, and the vibration of the belt 35 is suppressed. It will never grow up.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

Next, FIG. 5 shows a second embodiment of the present invention. In the case of the present embodiment, contrary to the case of the above-described first embodiment, the cylinder cylinder 50 constituting the damper device 31a is supported in the recess 49 of the swing-side arm piece 32a , and the projection piece 48 (see FIG. 2). The plunger 53 can be freely brought into contact with the tip of the. Therefore, the amount of protrusion of the plunger 53 changes as the swing member 23a swings. Other configurations and operations are the same as in the case of the above-described first embodiment.

[Brief description of 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 with the cylinder tube retracted.

FIG. 4 is a sectional view similar to FIG. 3, showing the cylinder cylinder in a protruding state.

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

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

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

FIG. 8 is a sectional view showing the prior invention.

[Explanation of symbols]

 1 belt 2 drive pulley 3 driven pulley 4 guide pulley or driven pulley 5 pulley 6 pivot 7 swing member 8 spring 9 bracket 10 swing member 11 shaft 12 damper device 13 cylinder 14 piston 15 compression spring 16 push rod 17, 18 chamber 19 Oil passage 20 Check valve 21 Fixed member 22 Fixed shaft 23, 23a Swing member 24 Pulley 25 Bolt 26 Torsion coil spring 27 Coil part 28a, 28b Locking part 29a, 29b Locking hole 30 Fixed arm piece 31, 31a Damper device 32, 32a Swinging side arm piece 33 Receiving block 34 Plunger 35 Belt 36 Cylindrical part 37 Bolt 38 Base body 39 Sliding bearing 40 Screw hole 41 Convex part 42 Rolling bearing 43 Inner ring 44 Bolt 45 Seat plate 46 Nut 47a, 47b Engagement Stop hole 48 Projection piece 49 Concave section 50 Shirin Da cylinder 51 Piston 52 Compression spring 53 Plunger 54 Circular hole 55 Notch 56 Ball 57 Second compression spring 58 Check valve 59 Seal material 60 Space 61 Sliding bearing

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 12, 1994

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of reference symbols] 1 belt 2 drive pulley 3 driven pulley 4 guide pulley or driven pulley 5 pulley 6 pivot 7 swing member 8 spring 9 bracket 10 swing member 11 shaft 12 damper device 13 cylinder 14 piston 15 compression spring 16 push Rod 17, 18 Chamber 19 Oil passage 20 Check valve 21 Fixing member 22 Fixed shaft 23, 23a Swing member 24 Pulley 25 Axis 26 Torsion coil spring 27 Coil part 28a, 28b Locking part 29a, 29b Locking hole 30 Fixing Side 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 body 39 Sliding bearing 40 Screw hole 41 Convex part 42 Rolling bearing 43 Inner ring 44 Bolt 45 Seat plate 46 Nuts 47a, 47b Locking holes 48 Projecting pieces 49 Recesses 50 Cylinder cylinder 51 Piston 52 Compression spring 53 Plunger 54 Circular hole 55 Notch 56 Ball 57 Second compression spring 58 Check valve 59 Seal material 60 Space 61 Sliding bearing

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (1)

[Scope of utility model registration request] 1. A fixed shaft provided on a base body to which an autotensioner is to be mounted, a swinging member whose base end is rotatably supported around the fixed shaft, and a swinging member provided at a tip end of the swinging member. And a pulley that is rotatably supported around the pivot, and a pair of locking portions at both ends of the coil portion. By disposing the pair of locking portions on the periphery and by locking the pair of locking portions to the base body and the swing member, respectively,
A torsion coil spring that applies an elastic force to the swing member in the direction of pressing the pulley toward the belt, and one end of the swing coil arm piece provided on the swing member are abutted and fixed to the base body. And a damper device in which the other end is brought into contact with the fixed side protruding piece, and the damper device includes a cylinder cylinder in which a viscous fluid is sealed, and an axial direction with respect to the cylinder cylinder inside the cylinder cylinder. And a spring that is provided between the piston and the cylinder cylinder and that urges the piston in one direction, and the piston relative to the cylinder cylinder based on the elastic force of the spring. A plunger that increases the amount of protrusion from the cylinder cylinder with displacement, a passage that communicates both axial end faces of the piston, and a check valve that opens and closes this passage are provided. The 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.