JP2017211049A - Auto Tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an auto tensioner capable of continuously acquiring stable dumping value with a friction resistance member even regardless of a long time operation.SOLUTION: A boss 22 provided at an opposite side from an attachment side of a tensioner pulley 4 in a tensioner arm 5 is fitted freely rotatably to the outer periphery of a support shaft 3 erected on a fixed base 2, a coil spring 6 for energizing the tensioner arm 5 in a rotation direction is arranged between the fixed base 2 and the tensioner arm 5 in an accumulated state in an axial direction at an outer side of the boss 22, the tensioner arm 5 is energized in a push-up direction, a friction resistance member 27 to be a resistance to the rotation of the tensioner arm 5 is dented to be attached to an upper end part of the support shaft 3 in pressure-contact with the boss 22, an outer peripheral frictional surface 29 of the friction resistance member 27 is formed in an inverted cone shape, and an inverted cone-shaped inner peripheral frictional surface 33 is formed at the same angle as the outer peripheral frictional surface 29 of the friction resistance member 27 in pressure-contact with the outer peripheral frictional surface 29 of the friction resistance member 27 at an upper opening 28 of the boss 22.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an auto tensioner used in a belt drive mechanism that transmits a driving force of an automobile engine to another driven pulley by a single transmission belt, for example.

  An auto tensioner is, for example, a belt drive mechanism that transmits the driving force of an automobile engine to another driven pulley by a single transmission belt, and prevents the transmission belt from being bent by applying tension to the transmission belt. The driven pulley is used to reliably transmit the driving force.

  Conventionally, as an auto tensioner, a fixed base fixed to a predetermined part such as an engine block, a support shaft standing on the fixed base, a tensioner pulley is rotatably attached to one end, and the other end is a support shaft A tensioner arm that is rotatably supported by the motor, and a coil spring that is disposed between the fixed base and the tensioner arm and urges the tensioner arm in the rotational direction. A boss is provided, and one end side of the support shaft is press-fitted and fixed to the boss, and in the tensioner arm, a boss is provided at substantially the center of the end opposite to the attachment side of the tensioner pulley. The fitting portion of the support shaft, which is rotatably fitted to the outer periphery of the other end of the support shaft and the boss of the tensioner arm is fitted, has an inverted conical shape with the end portion diameter increasing toward the end portion. Wait The boss of the tensioner arm also has an inverted conical shape corresponding to the fitting part of the support shaft, and the coil spring is disposed in a state where pressure is accumulated in the axial direction between the fixed base and the tensioner arm. A cylindrical frictional resistance member made of a synthetic resin is installed between the boss of the tensioner arm and the support shaft so as to resist the rotation of the tensioner arm. In addition, there is an auto tensioner that is prevented from rotating with a fitting portion of the support shaft (see, for example, Patent Document 1).

  The auto tensioner configured as described above has a damping function that acts on the tensioner arm by a cylindrical frictional resistance member interposed between the boss of the tensioner arm and the support shaft, thereby damping the vibration of the transmission belt. The tension is effectively applied to the transmission belt.

JP 2008-32037 A

In the auto tensioner configured as described above, the cylindrical frictional resistance member interposed between the boss of the tensioner arm and the support shaft has the stability of the fitting body between the boss of the tensioner arm and the support shaft. From this point, the fitting length of the boss of the tensioner arm to be fitted to the support shaft, that is, the cylinder length is substantially the same as the cylinder length. Therefore, the contact surface between the boss of the tensioner arm and the cylindrical frictional resistance member, that is, the frictional surface is large, and the cylindrical frictional resistance member that is generated by the heat generation of the cylindrical frictional resistance member due to long-time operation increases expansion and deformation. As a result, there is a problem that a stable damping value may not be obtained, for example, the frictional resistance of rotation of the boss of the tensioner arm and the support shaft increases or decreases.
In recent years, vehicles such as an idling stop have been developed to improve fuel economy, which requires a stable auto tensioner with a very good damping value.

  An object of the present invention is to provide an auto tensioner capable of continuously obtaining a stable damping value with a frictional resistance member even when operated for a long time.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a fixed base, a support shaft erected substantially at the center of the fixed base, and a tensioner pulley rotatably attached to one end. A tensioner arm having the other end rotatably supported by the support shaft, and a coil spring disposed between the fixed base and the tensioner arm and biasing the tensioner arm in the rotation direction, In the tensioner arm, a boss is provided at substantially the center of the end opposite to the mounting side of the tensioner pulley, the boss is rotatably fitted on the outer periphery of the support shaft, and the boss of the tensioner arm is On the outside, the coil spring is disposed in a state where pressure is accumulated in the axial direction between the fixed base and the tensioner arm, and the tensioner arm is urged in the push-up direction to A friction resistance member that is pressed against the boss of the tensioner arm that is biased in the push-up direction by the coil spring and is a rotation resistance of the tensioner arm is fixed to the portion, and the friction resistance The member has an outer peripheral friction surface formed in an inverted conical shape, and the upper end opening of the boss is formed at the same angle as the outer peripheral friction surface of the friction resistance member, and an inverted cone that presses against the outer peripheral friction surface of the friction resistance member. An inner peripheral friction surface is formed.

According to the first aspect of the present invention, the upper end portion of the support shaft is in pressure contact with the boss of the tensioner arm that is urged in the push-up direction by the coil spring, thereby providing resistance to rotation of the tensioner arm. A frictional resistance member is attached to be prevented from rotating, and the frictional resistance member has an outer peripheral friction surface formed in an inverted conical shape, and the upper end opening of the boss has the same angle as the outer peripheral frictional surface of the frictional resistance member. Since an inverted conical inner circumferential friction surface that is formed and press-contacted with the outer circumferential friction surface of the friction resistance member is formed, an outer circumferential friction surface having a large area can be obtained even if the vertical length of the friction resistance member is short. The required frictional resistance to obtain the desired damping value can be generated, and the frictional resistance member changes the area of the outer peripheral friction surface by changing the angle of the inverted conical outer peripheral friction surface Since bets can, by setting the angle of the outer circumferential friction surface in response to the damping value to determine, it is possible to generate the required frictional resistance.
Further, since the area of the outer peripheral friction surface can be changed by changing the vertical length of the friction resistance member without changing the angle of the outer peripheral friction surface, the frictional resistance required for the required damping value can be easily obtained. It can be generated reliably.
Even if the frictional resistance member generates a large expansion or deformation due to the heat generated by the frictional resistance member during a long operation, the expansion or deformation is absorbed by the elasticity of the coil spring that urges the tensioner arm in the push-up direction. Therefore, an increase in the frictional resistance between the boss of the tensioner arm and the frictional resistance member can be suppressed, and a stable damping value can be continuously obtained.
Further, the boss of the tensioner arm is fitted to the outer periphery of the support shaft, and the friction resistance member is not interposed between the boss of the tensioner arm and the support shaft, so that the tensioner is not affected by the friction resistance member. A stable fitting body can be obtained between the boss of the arm and the support shaft.

  The invention according to claim 2 is characterized in that the inclination angle of the outer peripheral friction surface of the frictional resistance member according to claim 1 is 30 ° to 88 °.

  According to the second aspect of the present invention, since the inclination angle of the outer peripheral friction surface of the frictional resistance member is 30 ° to 88 °, the damping required between the frictional resistance member and the boss of the tensioner arm. The necessary frictional resistance for obtaining the value can be easily generated. When the inclination angle is less than 30 °, the diameter of the frictional resistance member must be increased in order to obtain the outer peripheral friction surface that generates the necessary frictional resistance. The length must be increased, and the size of the apparatus is inevitably increased accordingly.

  According to a third aspect of the present invention, the frictional resistance member according to the first or second aspect is interposed between the boss of the tensioner arm and the support shaft standing on the fixed base. It is characterized by being molded integrally with the bushing.

  According to a third aspect of the present invention, the frictional resistance member is formed integrally with a bush interposed between the boss of the tensioner arm and the support shaft standing on the fixed base. As a result, the number of parts is reduced, and the assembly work becomes easier.

  According to the autotensioner according to the present invention, a stable damping value can be continuously obtained by the frictional resistance member even when operated for a long time.

It is a top view showing the 1st example of an embodiment of an auto tensioner concerning the present invention. It is a longitudinal cross-sectional view of FIG. It is a perspective view which shows the fixed base used in the 1st example. It is a longitudinal cross-sectional view of FIG. It is a top view which shows the tensioner arm currently used in the 1st example. It is a longitudinal cross-sectional view of FIG. It is a perspective view from the upper surface side of FIG. It is a perspective view from the lower surface side of FIG. It is a top view which shows the frictional resistance member currently used in the 1st example. FIG. 10 is a front view of FIG. 9. FIG. 10 is a sectional view taken along line AA in FIG. 9. It is a top view which shows the holding | maintenance board which prevents the pull out of the frictional resistance member attached to the upper end part of the support shaft of a fixed base, and hold | maintains an attachment state. It is the BB sectional view taken on the line of FIG. It is a top view which shows the bush interposed between the boss | hub of the tensioner arm shown in a 1st example, and the support shaft of a fixed base. It is a front view of FIG. It is CC sectional view taken on the line of FIG. It is a longitudinal section showing the 2nd example of an embodiment of an auto tensioner concerning the present invention. It is a top view which shows the friction resistance member and bush used in the 2nd example. It is a front view of FIG. It is the DD sectional view taken on the line of FIG.

Embodiments of an auto tensioner according to the present invention will be described below in detail with reference to the drawings.
1 to 15 show a first example of an embodiment of an auto tensioner according to the present invention. FIG. 1 is a plan view showing the auto tensioner of this example. FIG. 2 is a longitudinal sectional view of FIG. 3 is a perspective view showing a fixed base used in the first example, FIG. 4 is a longitudinal sectional view of FIG. 3, FIG. 5 is a plan view showing a tensioner arm used in the first example, and FIG. 5 is a perspective view from the upper surface side of FIG. 5, FIG. 8 is a perspective view from the lower surface side of FIG. 5, and FIG. 9 is a plan view showing the friction resistance member used in the first example. 10 is a front view of FIG. 9, FIG. 11 is a sectional view taken along line AA of FIG. 9, FIG. 12 is a plan view showing a mounting plate for attaching a friction resistance member to the upper end portion of the support shaft of the fixed base, and FIG. 12 is a cross-sectional view taken along line BB in FIG. 12, and FIG. 14 shows a bush interposed between the boss of the tensioner arm and the support shaft of the fixed base shown in the first example. Plan view, FIG. 15 is a front view of FIG. 14, FIG. 16 is a sectional view taken along line C-C of Figure 14.

  The auto tensioner 1 of this example includes a fixed base 2 fixed to a predetermined portion of a fixed portion X such as an engine block, a support shaft 3 standing at a substantially center of the fixed base 2, and a tensioner pulley at one end. 4 is rotatably attached, and the other end is fitted between the outer periphery of the support shaft 3 and is rotatably supported. The tensioner arm is disposed between the fixed base 2 and the tensioner arm 5. 5 and a coil spring 6 for urging 5 in the rotational direction.

In the fixed base 2, a cylindrical portion 8 that forms an accommodation chamber 7 for accommodating the coil spring 6 together with a cylindrical portion that will be described later provided on the tensioner arm 5 is provided around the support shaft 3. It has been.
A locking groove portion 9 is provided on the inner surface of the cylindrical portion 8 so that the one end portion 6a of the coil spring 6 is locked by the spring of the coil spring 6 in the winding direction. Is provided with a fixing ring 11 that constitutes a part of a temporary fixing mechanism 10 that temporarily fixes the tensioner arm 5 to the fixed base 2 in a state where the coil spring 6 is accumulated in the winding direction.

  In the support shaft 3 erected on the fixed base 2, a shaft hole 12 is formed in the center in this example, and a fixing bolt 13 is inserted into the shaft hole 12 and provided in the fixed portion X. The fixed base 2 is fixed to the fixed portion X by being screwed into the female screw hole 14.

Further, on the outer peripheral surface of the support shaft 3, there is a key groove 15 that prevents rotation of a frictional resistance member (described later) attached to the upper end portion of the support shaft 3, and between the boss of the tensioner arm 5 and the support shaft 3. A key groove 16 serving as a detent for the interposed bush is formed in the axial direction.
Further, the upper end of the support shaft 3 has a small diameter that prevents a frictional resistance member, which will be described later, attached to the upper end portion of the support shaft 3 from being pulled out and fits the outer periphery of a ring-shaped holding plate 17 that holds the attached state. The holding plate 17 fitted to the small diameter portion 18 is clamped and fixed between the large diameter step portion 19 of the support shaft 3 by caulking the upper edge of the small diameter portion 18. Yes. A knurl 21 is formed on the inner periphery of the fitting hole 20 of the holding plate 17 to prevent the rotation of the holding plate 17 by biting the crimped upper edge of the small diameter portion 18.

In the tensioner arm 5, a boss 22 that is rotatably fitted to the outer periphery of the support shaft 3 is provided on the lower surface side at the substantially center of the end opposite to the mounting side of the tensioner pulley 4. A cylindrical portion 23 that forms the accommodating chamber 7 that accommodates the coil spring 6 together with the cylindrical portion 8 provided at the edge of the fixed base 2 is provided so as to surround the boss 22.
Further, the inner surface of the cylindrical portion 23 is provided with a locking groove portion 24 in which the other end portion 6b of the coil spring 6 is locked by the repelling of the coil spring 6 in the winding direction. A fixing ring 25 constituting a part of the temporary fixing mechanism 10 that temporarily fixes the tensioner arm 5 to the fixed base 2 in a state where the coil spring 6 is accumulated in the winding direction is provided on the outer surface.

  The fixing ring 25 is configured to overlap with the fixing ring 11 provided on the fixed base 2. When the fixing ring 25 and the fixing ring 11 provided on the fixed base 2 are overlapped, a coil spring 6 to be described later is attached. The pressure is accumulated in the winding direction, and the coil spring 6 can be held in the state accumulated pressure in the winding direction by inserting an appropriate detachable stopper into the fixing ring 25 and the fixing ring 11 provided on the fixed base 2. It has become.

  A pulley shaft hole 26 for rotatably mounting the tensioner pulley 4 is provided on the tensioner arm 5 on the side where the tensioner pulley 4 is mounted.

In the coil spring 6, the coil spring 6 is disposed on the outer periphery of the boss 22 of the tensioner arm 5 fitted to the outer periphery of the support shaft 3 of the fixed base 2. The one end 6 a is locked to the locking groove 9 provided on the fixed base 2 by the spring in the winding direction of the coil spring 6, and the other end 6 b is locked to the locking groove 24 provided on the tensioner arm 5. The coil spring 6 is locked by the spring in the winding direction, and is configured to accumulate pressure in the winding direction when it overlaps the fixing ring 25 and the fixing ring 11 provided on the fixed base 2. Yes.
The coil spring 6 is disposed in a state where pressure is accumulated in the axial direction between the fixed base 2 and the tensioner arm 5, and constantly urges the tensioner arm 5 in the upward direction.

  Further, the upper end portion of the support shaft 3 of the fixed base 2 is pressed against the upper end opening portion of the boss 22 of the tensioner arm 5 urged in the upward direction by the coil spring 6, and becomes resistance to rotation of the tensioner arm 5. The frictional resistance member 27 is attached while being prevented from rotating. The friction resistance member 27 is made of synthetic resin.

The frictional resistance member 27 has an outer peripheral friction surface 29 that press-contacts with the upper end opening 28 of the boss 22 in an inverted conical shape, and a fitting hole 30 that fits the outer periphery of the upper end of the support shaft 3 is formed at the center. Yes. A key 31 is formed on the inner periphery of the fitting hole 30 to engage with the key groove 15 formed on the outer peripheral surface of the support shaft 3 and prevent rotation when the upper end of the support shaft 3 is engaged. ing.
The friction resistance member 27 fitted to the outer periphery of the upper end portion of the support shaft 3 is pressed on the upper surface by the holding plate 17 fixed to the upper end of the support shaft 3 and is prevented from coming off from the support shaft 3.
In order to obtain an effective resistance force against the rotation of the tensioner arm 5 required for causing the tensioner arm 5 to function as a damping function, the outer circumferential friction surface 29 of the frictional resistance member 27 formed in an inverted conical shape is provided with a longitudinal groove. A plurality of 32 are formed in the circumferential direction.

The upper end opening 28 of the boss 22 to which the outer peripheral friction surface 29 of the frictional resistance member 27 presses is formed at the same inclination angle θ as the outer peripheral friction surface 29 of the frictional resistance member 27. An inverted conical inner circumferential friction surface 33 that is in pressure contact is formed.
The inclination angle θ of the outer peripheral friction surface 29 of the frictional resistance member 27 is preferably 30 ° to 88 °, and particularly preferably 60 ° to 88 °. If the inclination angle θ of the outer peripheral friction surface 29 of the frictional resistance member 27 is 30 ° to 88 °, the frictional resistance necessary for obtaining the required damping value between the frictional resistance member 27 and the boss 22 of the tensioner arm 5. Can be generated. When the inclination angle θ is less than 30 °, the diameter of the frictional resistance member 27 must be increased in order to obtain the outer peripheral friction surface 29 that generates the necessary frictional resistance, and when the inclination angle θ exceeds 88 °. The length of the frictional resistance member 27 in the vertical direction must be increased, and the size of the apparatus is inevitably increased accordingly.

  In this example, a bush 34 is interposed between the boss 22 of the tensioner arm 5 and the support shaft 3. A key 35 is formed on the inner periphery of the bush 34 to engage with the key groove 16 formed on the outer peripheral surface of the support shaft 3 when the bush 34 is fitted to the outer periphery of the support shaft 3.

The auto tensioner 1 of this example configured as described above is provided on the fixing ring 11 and the tensioner arm 5 provided on the fixing base 2 constituting the temporary fixing mechanism 10 in a state before being fixed to the fixed portion X. The fixing ring 25 is overlapped, an appropriate stopper is inserted and fixed to the fixing ring 11 and the fixing ring 25, and the coil spring 6 is in a state of accumulating pressure in the winding direction.
In the auto tensioner 1 in such a state, the fixed portion X is screwed into a female screw hole 14 provided in the fixed portion X by screwing a fixing bolt 13 inserted through a support shaft 3 erected on the fixed base 2. It is fixed to the predetermined part.

  The tensioner pulley 4 attached to the tensioner arm 5 of the auto tensioner 1 fixed to a predetermined portion of the fixed portion X is pressed against the transmission belt by temporarily pulling a stopper from the fixing ring 11 and the fixing ring 25 to temporarily fix it. The tension of the tensioner arm 5 is rotated by the elastic force of the coil spring 6 which has been unfixed and accumulated in the winding direction, and the tensioner pulley 4 is pressed against the transmission belt, and the transmission belt is tensioned. Is granted.

  For example, when vibration is generated in the transmission belt due to engine start / stop, the inner peripheral friction surface 33 in the upper end opening 28 of the boss 22 of the tensioner arm 5 and the upper end of the support shaft 3 of the fixed base 2 The vibration of the transmission belt is attenuated by a damping function that acts on the tensioner arm 5 by the frictional resistance with the outer peripheral friction surface 29 of the attached frictional resistance member 27.

  According to the auto tensioner 1 of this example, an upper end opening 28 of the boss 22 of the tensioner arm 5 urged in the upward direction by the coil spring 6 is formed on the upper end portion of the support shaft 3 erected on the fixed base 2. A frictional resistance member 27 that is pressed against and serves as a resistance against rotation of the tensioner arm 5 is fixed to be prevented from rotating. Are formed at the same angle as the outer peripheral friction surface 29 of the frictional resistance member 27 and are formed with an inverted conical inner peripheral frictional surface 33 that presses against the outer peripheral frictional surface 29. Even if the length is short, the outer peripheral friction surface 29 having a large area can be obtained, and the necessary frictional resistance for obtaining the required damping value can be generated.

Since the friction resistance member 27 can change the area of the outer peripheral friction surface 29 by changing the angle θ of the inverted conical outer peripheral friction surface 29, the angle θ of the outer peripheral friction surface 29 is set according to the required damping value. By doing so, a necessary frictional resistance can be generated.
Further, since the area of the outer peripheral friction surface 29 can be changed by changing the vertical length of the friction resistance member 27 without changing the angle θ of the outer peripheral friction surface 29, the frictional resistance required for the required damping value can be obtained. It can be generated easily and reliably.

  Further, even if the frictional resistance member 27 is greatly expanded or deformed due to the heat generation of the frictional resistance member 27 due to long-time operation, the expansion or deformation is absorbed by the elasticity of the coil spring 6 that urges the tensioner arm 5 in the push-up direction. Therefore, an increase in frictional resistance between the boss 22 of the tensioner arm 5 and the frictional resistance member 27 can be suppressed, and a stable damping value can be continuously obtained.

  In addition, since the friction resistance member 27 is not interposed at the fitting portion between the boss 22 of the tensioner arm 5 and the support shaft 3, the boss 22 of the tensioner arm 5 and the support shaft 3 are stable without being affected by the friction resistance member 27. A fitting state can be obtained.

  Further, in this example, since the inclination angle θ of the outer peripheral friction surface 29 of the friction resistance member 27 is 30 ° to 88 °, a damping value to be obtained is obtained between the friction resistance member 27 and the boss 22 of the tensioner arm 5. Therefore, it is possible to easily generate the necessary frictional resistance.

17 to 20 show a second example of the embodiment of the auto tensioner according to the present invention, FIG. 17 is a longitudinal sectional view of the auto tensioner of the second example, and FIG. 18 is used in the second example. FIG. 19 is a front view of FIG. 18, and FIG. 20 is a sectional view taken along the line DD of FIG.
About the auto tensioner 1 of this example, the same code | symbol is attached | subjected about the structure same as a 1st example, the description is abbreviate | omitted, and only a structure different from a 1st example is demonstrated.

  In this example, the configuration different from the first example is only the frictional resistance member 27 and the bushing 34. In the first example, the frictional resistance member 27 and the bushing 34 are configured separately, whereas in the second example, The friction resistance member 27 and the bush 34 are integrally formed.

In the auto tensioner 1 of this example configured as described above, the number of parts is reduced by one as compared with the first example, so that the assembling work is facilitated accordingly.
Other configurations and effects are the same as those of the first example, and thus the description of the first example is cited.

DESCRIPTION OF SYMBOLS 1 Auto tensioner 2 Fixed base 3 Support shaft 4 Tensioner pulley 5 Tensioner arm 6 Coil spring 6a One end part of a coil spring 6b The other end part of a coil spring 7 Storage chamber 8 Cylindrical part 9 Locking groove part 10 Temporary fixing mechanism 11 Fixing ring 12 shaft hole 13 fixing bolt 14 female screw hole 15 key groove 16 key groove 17 holding plate 18 small diameter part 19 large diameter step part 20 fitting hole 21 knurl 22 boss 23 cylindrical part 24 locking groove part 25 fixing ring 26 pulley shaft hole 27 Friction resistance member 28 Upper end opening 29 Outer friction surface 30 Fitting hole 31 Key 32 Vertical groove 33 Inner friction surface 34 Bush 35 Key

Claims (3)

A fixed base, a support shaft standing substantially at the center of the fixed base, a tensioner arm having a tensioner pulley rotatably attached to one end thereof, and a other end rotatably supported by the support shaft; A coil spring disposed between the fixed base and the tensioner arm and biasing the tensioner arm in the rotational direction.
In the tensioner arm, a boss is provided at substantially the center of the end opposite to the attachment side of the tensioner pulley, the boss is rotatably fitted to the outer periphery of the support shaft, and the boss of the tensioner arm The coil spring is arranged in a state where pressure is accumulated in the axial direction between the fixed base and the tensioner arm, and the tensioner arm is urged in the push-up direction to the upper end of the support shaft. Is attached to the boss of the tensioner arm that is urged in the push-up direction by the coil spring, and a frictional resistance member that serves as a resistance to rotation of the tensioner arm is prevented from rotating. The outer peripheral friction surface is formed in an inverted conical shape, and the upper end opening of the boss is formed at the same angle as the outer peripheral friction surface of the friction resistance member. Auto tensioner, characterized in that the inverted cone-shaped inner circumferential friction surface pressed against the surface is formed.   The auto tensioner according to claim 1, wherein an inclination angle of an outer peripheral friction surface of the frictional resistance member is 30 ° to 88 °.   The frictional resistance member is formed integrally with a bush interposed between the boss of the tensioner arm and the support shaft standing on the fixed base. 2. The auto tensioner according to 2.

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