JP2682800B2 - Damping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping device used for an auto-tensioner or the like which attenuates a belt reaction force as an external force while applying a tension to a timing belt of an automobile engine or a driving belt for accessories and the like, and more particularly to a structure thereof. On measures to simplify the process.

[0002]

2. Description of the Related Art Conventionally, as this type of damping device, a hydraulic damping device has been widely used, and an example of such a damping device is disclosed in Japanese Utility Model Laid-Open Publication No. 4-66448.

In this structure, a cylinder body filled with hydraulic oil, a piston that is reciprocally fitted into the cylinder body, and divides the cylinder body into two first and second oil chambers, A piston rod having an inner end portion movably connected to a piston and penetrating an end wall of the cylinder on the side of the first oil chamber, and a piston rod that is compressed into a second oil chamber and extends the cylinder And a compression coil spring that pushes and urges the oil chamber toward the oil chamber. A communication passage that connects the oil chambers to each other is provided in each of the piston and the cylinder body, and a check valve is provided in the communication passage on the piston side.

In the above-described check valve, the piston moves in the direction opposite to the biasing direction of the compression coil spring due to the action of an external force in the contracting direction of the cylinder, and the hydraulic oil in the second oil chamber will flow into the first oil chamber. When the cylinder is extended, the piston moves in the biasing direction and the hydraulic oil in the first oil chamber attempts to flow into the second oil chamber. When it does, it operates so as to open the communication passage to allow the movement of the piston. Thus, when the piston is pressed in a direction opposite to the biasing direction and an external force in the cylinder contraction direction is applied to the tip of the piston rod, the movement of the piston is suppressed, and thus the external force is attenuated. ing.

[0005]

However, in the above-mentioned hydraulic damping device, since the flow resistance of hydraulic oil is used, a high sealing property is required and the structure becomes complicated. Therefore, there is a problem that the number of parts tends to increase and it takes time to assemble, and it is difficult to reduce the cost.

Further, when an excessive external force is applied, the pressure of the hydraulic oil rises in proportion to the external force, so that the damping device itself may be damaged by the high pressure.

Further, since the damping characteristic is determined by the flow path resistance of the communication path and the check valve, it is difficult to change and adjust the damping characteristic in a damping device in which a predetermined damping characteristic is already set. Therefore, in order to change the damping characteristics, the damping device itself must be replaced.

Further, regarding the damping characteristic, the viscosity characteristic of the hydraulic oil is easily affected by the temperature change. For example, the flow resistance of the hydraulic oil increases at a low temperature as compared with the normal temperature, and the damping force becomes larger than a predetermined value. There are difficulties such as becoming.

The present invention has been made in view of the above points, and a main object thereof is to reduce the number of parts by using a pulley member and a friction member such as a belt wound around the pulley member. In order to reduce the cost by making it easy to assemble, it is necessary to provide a fail-safe function against excessive external force, and to make it easy to tune the damping characteristics and to reduce the temperature dependency. is there.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, when the tension of both spans of an endless friction member wound between two pulley members changes, the pulley member and the endless friction member change. Utilizing the fact that the grip force between the friction member is changed, the grip force is changed according to the external force to be damped, so that a damping force according to the external force is obtained, whereby the component While reducing the number of points and facilitating assembly work to contribute to cost reduction, excessive external force is dealt with by slippage between the pulley member and friction member, and the span tension change rate is adjusted. By doing so, the setting of the damping characteristics can be easily tuned, and the temperature dependency is reduced because no hydraulic oil is required.

Specifically, according to the present invention, a fixed pulley member fixed to the fixed side and having a substantially arcuate friction surface on the outer periphery, and a fixed pulley member rotatably supported by the fixed pulley member and damping are provided. A lever member having an acting force portion on which an external force to be applied is provided, and the lever member is non-rotatably supported on the same surface side as the fixed pulley member, and has a substantially circular shape which forms a pair with the friction surface of the fixed pulley member on the outer periphery. A moving pulley member having an arcuate friction surface, an endless friction member wound between the friction surface of the fixed pulley member and the friction surface of the moving pulley member, and between the friction surfaces of the pulley members of the friction member. And a pressing means for pressing one of the spans located at.

According to another aspect of the present invention, there is provided a fixed plate fixed to the fixed side, a lever member rotatably supported by the fixed plate, and a lever member having an acting force portion on which an external force to be damped acts. This lever member is non-rotatably supported on the same side as the fixed plate, and has a moving pulley member having a substantially arc-shaped friction surface on the outer periphery, and an intermediate portion moves while both ends are fixed to the fixed plate. A friction member wound around the friction surface of the pulley member and a pressing means for pressing one of the spans defined by the friction surface of the moving pulley member of the friction member are provided.

According to the third aspect of the present invention, in the first or second aspect,
In the invention of claim 1, the pressing means is integrated with the lever member.
The lever member is supported so as to rotate .

[0014]

With the above construction, in the invention of claim 1 or 2, one span of the friction member is pressed by the pressing means, and the moving pulley member is non-rotatably supported by the lever member. When the member rotates, a grip force is generated between the friction member and the friction surface of the pulley member,
The rotation of the lever member receives resistance. That is,
The damping force acts on the external force that attempts to rotate the lever member.

At this time, when the lever member rotates in the direction in which the span pressed by the pressing means changes to the tension side span, the span on the side opposite to the span becomes the slack side span and the tension decreases. Since the grip force between the friction member and the pulley member decreases, the damping force at this time is small.
On the other hand, when the lever member rotates in the direction in which the span pressed by the pressing means changes to the slack side span, which is opposite to the above-described rotation direction, the tension of the span is reduced by being pressed by the pressing means. A large damping force is generated because the grip force is avoided and the grip force is maintained. Therefore, since the magnitude of the damping force changes according to the turning direction of the lever member, a bidirectional damping characteristic is obtained in which the magnitude of the damping force with respect to the external force varies depending on the direction in which the external force acts on the lever member. To be

When the turning force of the lever member due to the external force increases, the damping force gradually increases, and the rate of slippage between the friction member and the pulley member also gradually increases. Then, when the turning power reaches a predetermined value, the slip ratio suddenly rises and easily shifts to a state where it becomes 100%, and the damping force takes a substantially constant value. Therefore, the friction member is prevented from being broken by the slip caused by an excessive external force.

Since the damping mechanism has a simple structure similar to the belt transmission mechanism in which one span of the transmission belt wound between the two pulleys is pressed by the pressing means, the number of parts is reduced. Is small and assembly work is easy. Further, since the damping force changes according to the change in tension of each span, the damping characteristic can be changed by adjusting the amount of change in tension of the span, and therefore the setting tuning of the damping characteristic is easy. Further, since a damping force is generated without using an operating body such as a working oil whose characteristics are easily changed by temperature, a stable damping characteristic with respect to a temperature change can be obtained.

In the invention of claim 3, the pressing means is
By being supported by the lever member so as to rotate integrally with the bar member, the positional relationship between the friction member and the span to be pressed becomes constant, so that the lever member rotates. Regardless of the position, the span can always be pressed under the same conditions, and stable damping characteristics can be obtained.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 to 3 show the overall structure of a damping device according to a first embodiment. This damping device is basically fixed to a fixed side f and has a circumferential shape on its outer circumference. A fixed pulley member 1 having a friction surface 1a, and a lever member 2 having an action force portion 2a rotatably supported by the fixed pulley member 1 about a rotation axis P and on which an external force to be damped acts. And the fixed pulley member 1 on the lever member 2.
The friction between the movable pulley member 3 which is non-rotatably supported on the same surface side as the movable pulley member 3 and which has a circumferential friction surface 3a which makes a pair with the friction surface 1a of the fixed pulley member 1 on the outer periphery and the fixed pulley member 1 described above. A flat belt 4 as an endless friction member wound between the surface 1a and the friction surface 3a of the moving pulley member 3, and a position between the friction surfaces 1a and 3a of both pulley members 1 and 3 of the flat belt 4. Span 4a, 4
and a pressing mechanism portion 5 as pressing means for pressing one side of b.

The fixed pulley member 1 has a cylindrical flat pulley portion 6 having a bottom and an opening on the front side (left side in FIG. 2).
The flat pulley portion 6 has a cylindrical shaft portion 7 extending from the center of the bottom portion to the front side along the rotation axis P. And
The friction surface 1 a is formed by the outer peripheral surface of the pulley portion 6.

The lever member 2 is made of a flat plate-shaped plate member whose width dimension gradually decreases outward from the rotation axis P in the radial direction. Further, a boss portion 8 projecting toward the rear side (right side in FIG. 2) is provided in the large diameter portion located around the rotation axis P, and the boss portion 8 of the fixed pulley member 1 is provided. Bearing 9 is attached to the shaft portion 7 from its tip side.
It is rotatably fitted to the outside via. The acting force portion 2a is provided at the turning end of the lever member 2. Further, at a substantially intermediate position between the boss portion 8 and the acting force portion 2a, a protruding piece portion 10 protruding rightward in FIG. 1 is provided.

The movable pulley member 3 is a flat pulley having the same pulley diameter as the flat pulley portion 6 of the fixed pulley member 1, and the outer peripheral surface thereof constitutes the friction surface 3a. The moving pulley member 3 is provided with a boss portion 8 of the lever member 2.
And a cylindrical shaft portion 11 projecting toward the rear side, which is the same as the boss portion 8 at a substantially intermediate position between the action force portion 2a and the action force portion 2a, is non-rotatably supported with respect to the lever member 2. That is, the pulley shaft center portion of the moving pulley member 3 is provided with the mounting holes 12 which are fitted to the shaft portion 11 of the lever member 2 from the tip end side thereof. The key member 13 is fitted in the key grooves 11a, 12a provided in the inner circumference of the pulley and extending in the pulley axial direction, respectively, so that the movable pulley member 3 is prevented from rotating. Further, a retaining ring 14 is fitted on the outer periphery of the tip end of the shaft portion 11, whereby the retaining of the moving pulley member 3 is prevented.

The pressing mechanism portion 5 is integrated with the lever member 2 and a pressing pulley 15 capable of pressing one span 4a of the flat belt 4 (span on the right side in FIG. 1) from the outer peripheral side.
Is provided on the lever member 2 so as to rotate with
It has a support arm 16 for guiding and supporting the pressing pulley 15 so as to be movable back and forth in the pressing direction, and a tension coil spring 17 for urging the pressing pulley 15 in the pressing direction. The support arm 16 is rotatably supported on the protruding piece 10 of the lever member 2 by a pivot pin 18 in the same rotation plane as the lever member 2. In addition, the pivot end of the support arm 16 has a shaft portion 16a protruding toward the rear side.
Is provided, and the pressing pulley 15 is rotatably supported on the shaft portion 16a. The tension coil spring 17 is interposed between the support arm 16 and the lever member 2.

Thus, in the above damping device, the flat belt 4 is
One of the spans 4a is pressed by the pressing mechanism portion 5 and the movable pulley member 3 is non-rotatably supported by the lever member 2. Therefore, when the lever member 2 rotates, it moves with the flat belt 4. A grip force is generated between each of the friction surfaces 3a and 1a of the pulley member 3 and the fixed pulley member 1,
As a result, the rotation of the lever member 2 receives resistance. That is, the damping force is applied to the external force that attempts to rotate the lever member 2.

At this time, when the lever member 2 is rotated in the direction A in which the span 4a pressed by the pressing mechanism portion 5 is changed to the tension side span, the span 4b opposite to the span 4a is loosened. It becomes a side span, the tension is reduced, and the grip force between the flat belt 4 and the moving pulley member 3 and the fixed pulley member 1 is reduced. Therefore, the damping force in this case is small. On the other hand, when the lever member 2 is rotated in the direction B in which the span 4a pressed by the pressing mechanism portion 5 is changed to the slack side span, the lever 4 is pressed because the span 4a is pressed. In this case, a large damping force is generated because the drop in tension is avoided and the grip force is maintained. Therefore, the magnitude of the damping force changes in accordance with the rotating direction of the lever member 2, so that the external force is applied
It is possible to obtain a damping characteristic having directivity such that the magnitude of the damping force changes depending on the direction in which the force acts on.

When the turning force of the lever member 2 due to the external force is increased, the damping force is gradually increased, while slippage occurs between the flat belt 4 and the movable pulley member 3 or the fixed pulley member 1. The rate of doing so will gradually rise.
When the turning power reaches a predetermined value, the slip ratio rapidly rises and easily shifts to a 100% state, and the damping force takes a substantially constant value. Therefore, with respect to an excessive external force, the fail-safe function of preventing the flat belt 4 from breaking due to the slipping is exerted.

Therefore, according to the first embodiment, a simple structure similar to that of the belt transmission mechanism in which one span of the transmission belt wound between two pulleys is pressed by the pressing means, The number of parts is small and assembly is easy. Further, since the damping force changes according to the tension change of each span 4a, 4b, the damping characteristic can be changed by adjusting the tension change amount of the span 4a, 4b, and the damping characteristic setting can be easily tuned. can do. In addition, since the damping force can be generated without using an actuating body whose operating characteristics such as hydraulic oil of a hydraulic damping device are easily affected by temperature changes, damping characteristics less affected by temperature changes can be obtained. it can.

Further, the pressing mechanism section 5 is integrated with the lever member 2.
By being supported by the lever member 2 so as to rotate as a body, the positional relationship between the flat belt 4 and the span 4a to be pressed is constant. The span 4a can always be pressed under the same conditions, and stable damping characteristics can be obtained. Further, since the friction surface 1a of the fixed pulley member 1 has a circular shape and the flat belt 4 is endless, the lever member 2 is at any rotation position around the rotation axis P, 360. The damping function can be exerted by operating over a rotation range of ° or more. Therefore, not only can the damping device be installed at an arbitrary rotation position around the rotation axis P, but also the amount of operation can be easily expanded without increasing the length of the rotation arm. .

In the first embodiment, one span 4a of the flat belt 4 is pressed from the outer peripheral side.
You may make it press from an inner peripheral side.

In the first embodiment, only one span 4a of the flat belt 4 is constantly pressed, but
The spans 4a and 4b may be alternately pressed depending on the rotating direction of the lever member 2.

Although the flat belt 4 is used as the friction member in the first embodiment, a V-belt or a V-ribbed belt may be used. In that case, a large gripping force can be obtained by forming the friction surface according to the sectional shape of the belt used.

On the contrary, a steel belt may be used as a friction member so that slip is likely to occur.

In the first embodiment, the friction surfaces 1a, 3a of the fixed pulley member 1 and the moving pulley member 3 are formed in a circular shape, but a necessary grip force with the friction member is obtained. It may be configured in an arc shape within the range.

Further, in the first embodiment, the slip between the friction member and the pulley member is used as a fail-safe function. However, since the damping force can be obtained even when the slip occurs, the double rotation of the lever member is possible. The normal range of damping may be set to include the level at which the slip ratio becomes 100% in the moving direction. In that case, no matter which direction the lever member rotates, the pulley member on the side where slippage occurs is provided with a restricting means for pinching the flat belt between the pulley member and the friction surface of the pulley member, and the lever member is damped. When the friction member is allowed to slip when it is rotated in the direction of large force,
The friction member can be circularly moved in one direction along with the reciprocating rotation of the lever member by configuring so that the slip is regulated when the friction member is rotated in the direction in which the damping force is small. It is preferable that the grip force with the moving pulley member can be prevented from being concentrated and applied to a specific portion of the friction member, and the load of the friction member can be evenly distributed over the entire friction member.

Further, although the endless friction member is used in the first embodiment, an endless friction member can be used. In that case, instead of the fixed pulley member 1,
You may use the fixing plate which can fix both ends of a friction member.

(Embodiment 2) An auto tensioner according to Embodiment 2 of the present invention will be described with reference to FIGS. This auto tensioner applies a predetermined tension to a V-belt t for driving auxiliary machinery by an automobile engine, and automatically changes the damping force for the tension adjusting operation according to the tension fluctuation. In the following description, the same parts as those in the first embodiment will be designated by the same reference numerals.

The above-mentioned auto tensioner is characterized in that it is fixed to an engine block f of an automobile engine and has a fixed pulley member 1 having a circumferential friction surface 1a on its outer periphery, and is rotatable about the fixed pulley member 1. And a lever member 2 having a tension pulley 2a rotatable about an axis Q parallel to the rotation axis P and the fixed pulley member 1 and the lever member 2, and fixed. A torsion coil spring 21 for urging the lever member 2 to rotate in a predetermined rotation direction A (counterclockwise direction in FIG. 4) with respect to the pulley member 1, and the pulley member 1 fixed to the lever member 2.
The friction between the movable pulley member 3 which is non-rotatably supported on the same surface side as the movable pulley member 3 and which has a circumferential friction surface 3a which makes a pair with the friction surface 1a of the fixed pulley member 1 on the outer periphery and the fixed pulley member 1 described above. An endless flat belt 4 wound between the surface 1a and the friction surface 3a of the moving pulley member 3.
And the friction surface 1 of both pulley members 1 and 3 of this flat belt 4.
and a pressing mechanism 5 for pressing one of the spans 4a and 4b located between a and 3a. Then, the tension pulley 2 is rotated by the rotational biasing force of the torsion coil spring 21.
The V-belt t is pressed against a to give a predetermined tension, while the lever member 2 rotates in the direction B (clockwise direction in the figure) opposite to the direction A of the rotational biasing force when the belt tension changes. When it is operated, its rotation is greatly attenuated.

In the fixed pulley member 1, the friction surface 1a is constituted by the front side portion (left side portion in FIG. 5) of the outer peripheral surface of the pulley portion 6 of the fixed pulley member 1. A cylindrical bearing portion 7 ′ that extends from the bottom of the pulley portion 6 toward the front side along the rotation axis P is provided concentrically with the pulley portion 6. Further, the pulley portion 6 has a rear side locking hole 22 formed in the inner surface of the peripheral wall thereof so as to extend radially outward.

A large diameter portion of the lever member 2 located around the rotation axis P is provided with a cylindrical shaft portion 8'projecting toward the rear side (right side in FIG. 5). Shaft 8 '
Is rotatably fitted in the bearing portion 7'of the fixed pulley member 1 from the front side through a bearing 9.
At the pivotal end of the lever member 2, a shaft portion 23 that projects toward the front side is provided on the same axis Q as the rear side shaft portion 11 that non-rotatably supports the movable pulley member 3. ing. A bolt hole 24 is provided in an axial center Q portion of the front side shaft portion 23, and a female screw is screwed on the inner periphery thereof. Further, a front side locking hole 25 is formed in the position near the shaft portion 8'of the lever member 2 toward the front side.

The tension pulley 2a is rotatably supported on the front shaft portion 23 of the lever member 2 via a bearing 26. The retaining bolts 27 screwed into the bolt holes 24 of the shaft portion 23 prevent the retaining.

The main body of the above-mentioned torsion coil spring 21 is left-handed, the end portion 21a located on the rear side of the body is directed outward in the radial direction, and the end portion 21b located on the front side is in the direction of the rotation axis P. Each has a shape protruding from the main body toward the front side. The rear end 21a is fitted in the rear locking hole 22 of the fixed pulley member 1, and the front end 21b is fitted in the front locking hole 25 of the lever member 2 to be locked in the circumferential direction. . Further, the main body is interposed in a diameter-reduced state so as to operate in a direction in which the diameter of the main body expands in a state where both end portions 21a and 21b are locked. It is designed to be motivated.

According to the above auto tensioner, when the lever member 2 rotates due to the fluctuation of the tension of the V-belt t wound around the tension pulley 2a , the lever member 2 is rotated in the direction opposite to the rotational biasing direction A. When rotating in the direction B, the rotation can be attenuated with a large force. On the other hand, when the lever member 2 rotates in the rotation urging direction A, the damping force for the rotation becomes small. Therefore, when the tension of the V-belt t rapidly increases, the rotation of the lever member 2 is suppressed, and thus, the flapping of the V-belt t can be prevented, while the lever member 2 rotates quickly when the tension decreases. It is possible to apply a predetermined tension to the V-belt t by rotating in the dynamic urging direction A.

When compared with the hydraulic type automatic tensioner, the hydraulic type tensioner uses a rotating member that rotatably supports the tension pulley while installing the cylinder along the traveling direction of the belt t. While the movement direction of the piston rod is changed by, for example, 90 °, the lever member 2 rotates, so that the tension pulley 2a is integrated and the lever member 2 extends along the traveling direction of the belt t. Can be arranged as. Therefore,
Due to the integration, the size and weight can be reduced, and the time and effort required for mounting the engine block f can be reduced by half.

(Embodiment 3) FIGS. 7 to 9 show the entire structure of an auto tensioner according to Embodiment 3, which is provided on a timing belt t for driving a cam shaft in an OHC engine of an automobile. It is a short arm type for giving tension and having a shorter arm length than that of the second embodiment. Incidentally, the above-mentioned Example 1
The same parts as those in the second embodiment are designated by the same reference numerals.

As a feature of the above automatic tensioner, the fixed pulley member 1 has a shaft portion 7 for rotatably supporting the rotating member 2 as a lever member. Further, the rotating member 2 has a cylindrical portion 31 which is rotatably fitted outside the shaft portion 7 of the fixed pulley member 1, and the tension pulley 2a is rotatable on the outer peripheral side of the cylindrical portion 31. It is designed to support.

The fixed pulley member 1 has a bottomed cylindrical rear case portion 32 whose front side (upper side in FIG. 8) is opened.
And a columnar portion 33 extending from the center of the bottom wall of the rear case portion 32 to the front side along the rotation axis P. The rear case portion 32 and the columnar portion 33 are the same as the rear case portion 32.
The small diameter portion 33 provided at the rear end portion (lower end portion in FIG. 8) of the cylindrical portion 33 is provided in the assembly hole 32a provided at the center of the bottom portion of the
It can be assembled integrally by inserting and fixing a. A rear side engagement slit 34 extending in the direction of the rotation axis P and reaching the opening edge of the rear case portion 32 is provided on a part of the peripheral wall of the rear case portion 32. On the other hand, the columnar portion 33 is provided with a bolt insertion hole 35 at a portion of the rotation axis P thereof. Further, the front end of the columnar portion 33 has a slightly large diameter, and the large diameter portion constitutes the pulley portion 6 of the fixed pulley member 1. Further, a flange portion 36 protruding outward in the radial direction is provided on the peripheral edge of the pulley portion 6 on the rear side over the entire circumference. The shaft portion 7 is formed by the portion of the columnar portion 33 extending from the flange portion 36 to the rear side.

The rotating member 2 has a bottomed cylindrical front case portion 37 which is open at the rear side and faces the opening portion of the rear case portion 32, and the front case portion 37 has the cylindrical shape. It is integrally provided at the rear opening end of the portion 31. A front locking slit 38 extending in the direction of the rotation axis P and reaching the opening edge of the front case portion 37 is provided on a part of the peripheral wall of the front case portion 37. The cylindrical portion 31 is supported by the shaft portion 7 of the fixed pulley member 1 via a resin bush 39 so as to be rotatable around the rotation axis P. On the other hand, on the outer peripheral side of the cylindrical portion 31, a tension pulley 2a for pressing the timing belt t is provided rotatably around the axis Q via a bearing 40. Further, the front end of the rotating member 2 is provided with a shaft portion 41 having a rectangular cross section that extends toward the front side along the rotation axis P.

A movable pulley member 3 consisting of a small-diameter flat pulley is externally fitted to the shaft portion 41 of the rotating member 2 from the front side in a mounting hole having a rectangular cross section provided in the shaft center portion thereof. As a result, the rotation member 2 is non-rotatably supported. A flat belt 4 having a short belt length is wound around the friction surface 1a of the fixed pulley member 1 and the friction surface 3a of the moving pulley member 3.

At the front end surface of the cylindrical portion 31 of the rotating member 2, one span 4a of the flat belt 4 is provided.
A pressing mechanism 5 for pressing (the lower span in FIG. 7) is provided. As shown in FIG. 9, the pressing mechanism section 5 has
A cylindrical portion 42 made of metal that can press the span 4a of the flat belt 4 from the outer peripheral side, and the cylindrical portion 42 is embedded in the tip end and is attached to the holding portion 43 of the rotating member 2 at the base end.
A resin spring 44 is held so as to rotate integrally with the rotating member 2 .

The rear case portion 32 of the fixed pulley member 1
A torsion coil spring 21 is interposed in a space between the rotation member 2 and the front case portion 37 of the rotation member 2 in a reduced diameter state.
The main body of the torsion coil spring 21 is left-handed, and the rear side and front side end portions 21a and 21b are respectively passed through the locking slits 34 and 38 and are locked. As a result, the tension pulley 2a is rotationally biased in the predetermined rotational direction A to press the timing belt t.

Therefore, according to the third embodiment, the same effects as those of the first and second embodiments can be obtained, and in addition, the fixed pulley member 1 rotatably supports the rotating member 2 on the shaft portion 7. Of the tension pulley 2a
Since it is housed inside the cylindrical portion 31 that rotatably supports, the rotating arm length of the auto tensioner is shortened, but the overall dimension in the rotating shaft center P direction is reduced.
Therefore, the total length of the automobile engine including the auto tensioner can be reduced.

Further, the fixed pulley member 1 and the rotating member 2
Since the moving pulley member 3 can be housed inside the tension pulley 2a, the entire auto tensioner can be made extremely compact up to the size of the tension pulley 2a.

Although the present invention is applied to the damping mechanism of the automatic tensioner in the second and third embodiments, it goes without saying that it can be applied to other devices for damping the external force.

[0055]

As described above, according to the first aspect of the present invention, the fixed pulley member fixed to the fixed side and having the substantially arcuate friction surface on the outer circumference, and rotatable to the fixed pulley member. And a lever member having an acting force portion on which an external force to be attenuated acts, and the lever member being non-rotatably supported on the same surface side as the fixed pulley member and having a fixed pulley member on the outer periphery. A moving pulley member having a substantially arcuate friction surface paired with the friction surface, and an endless friction member wound between the friction surface of the fixed pulley member and the friction surface of the moving pulley member,
Since the pressing member for pressing one of the spans located between the friction surfaces of the pulley members of the friction member is provided, it is possible to easily assemble with a small number of parts and to reduce the cost. It is possible to provide a fail-safe function against an excessive external force, to easily change the setting of the damping characteristic, and to reduce the temperature dependence of the damping characteristic.

According to the second aspect of the present invention, the lever member having the fixed plate fixed to the fixed side and the action force portion rotatably supported by the fixed plate and on which the external force to be attenuated acts. A movable pulley member which is non-rotatably supported by the lever member on the same surface side as the fixed plate and has a substantially arc-shaped friction surface on the outer periphery, and an intermediate portion with both ends fixed to the fixed plate. Is provided with a friction member wound around the friction surface of the moving pulley member, and a pressing means for pressing one of the spans defined by the friction surface of the moving pulley member of the friction member. The same effect as that of the first aspect of the invention can be obtained.

According to the third aspect of the present invention, the pressing means is configured to rotate together with the lever member.
Since it is supported by the member, the predetermined span of the friction member can always be pressed under the same condition regardless of the turning position of the lever member, and stable damping characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing a damping device according to a first embodiment of the present invention.

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

FIG. 3 is a rear view showing the damping device.

FIG. 4 is a front view showing an auto tensioner according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a rear view showing the auto tensioner.

FIG. 7 is a front view showing an auto tensioner according to a third embodiment of the present invention.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a partially enlarged perspective view of a pressing mechanism portion.

[Explanation of symbols]

 1 fixed pulley member 1a friction surface 2 lever member, rotating member 2a acting force part, tension pulley 3 moving pulley member 3a friction surface 4 flat belts (friction members) 4a, 4b span 5 pressing mechanism part (pressing means) P rotation Shaft center f Fixed side, engine block

Claims (3)

(57) [Claims] 1. A fixed pulley member fixed to a fixed side and having a substantially arcuate friction surface on the outer circumference, and an action of being rotatably supported by the fixed pulley member and exerting an external force to be damped. A movement having a lever member having a force portion and a non-rotatably supported on the lever member on the same surface side as the fixed pulley member, and having a substantially arcuate friction surface on the outer periphery which is paired with the friction surface of the fixed pulley member. A pulley member; an endless friction member wound between the friction surface of the fixed pulley member and the friction surface of the moving pulley member; and one of the spans located between the friction surfaces of the pulley members of the friction member. A damping device comprising: a pressing unit that presses. 2. A fixing plate fixed to a fixed side, a lever member rotatably supported by the fixing plate and having an acting force portion on which an external force to be damped acts, and a lever member fixed to the lever member. A movable pulley member that is non-rotatably supported on the same side as the plate and that has a substantially arcuate friction surface on the outer periphery, and an intermediate portion in which the both ends are fixed to the fixed plate. A damping device, comprising: a friction member wound around the friction member; and a pressing unit that presses one of the spans defined by the friction surface of the moving pulley member of the friction member. 3. The damping device according to claim 1 or 2, wherein the pressing means rotates integrally with the lever member.
A damping device supported by the lever member .