JP2019128032A - Belt tensioner - Google Patents

Abstract

To solve such a problem that an inclination angle of a transmission belt wound around tensioner pulley may be excessively enlarged.SOLUTION: An insertion hole 26 is provided in an arm member 25, and the arm member 25 is connected to a support member 21 so as to be turnable by the insertion of a connecting shaft 24 into the insertion hole 26. A flange part 24b protruding toward the outside of the connecting shaft 24 in a radial direction is provided in the connecting shaft 24. A cylindrical first bush 35 is interposed between an internal circumferential surface of the insertion hole 26 and an external circumferential surface of the connecting shaft 24. A radial thickness of the first bush 35 becomes thicker as progressing toward a center side of the first bush 35 in a center axis line direction. A cylindrical second bush 36 is interposed between the flange part 24b and the arm member 25. A thickness of the second bush 36 in a center axis line direction becomes thin as progressing toward the radial outside of the second bush 36.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a belt tensioner.

  The belt tensioner of Patent Document 1 includes a support member attached to an internal combustion engine. An arm member is coupled to the support member via a coupling shaft. The arm member is rotatable with respect to the support member about the central axis of the connecting shaft. Moreover, a pulley is attached to the arm member so as to be rotatable with respect to the arm member. A transmission belt for transmitting rotational torque from the crankshaft to other auxiliary machines is wound around the pulley. And tension is given to a transmission belt because an arm member rotates by the energizing force of a spring member.

JP 2001-173737 A

  A transmission belt wound around a pulley of a belt tensioner as disclosed in Patent Document 1 is also wound around another pulley. If the position of the pulley of the belt tensioner is shifted from that of the other pulley in the direction of the central axis of the pulley of the belt tensioner, the transmission belt is slanted between these two pulleys.

  Specifically, as shown in FIG. 6, the transmission belt 101 wound around the pulley 100 of the belt tensioner is also wound around, for example, a crank pulley 102 which rotates integrally with the crankshaft. In general, the central axis J 1 of the pulley 100 in the belt tensioner extends parallel to the central axis J 2 of the crank pulley 102. The pulley 100 of the belt tensioner is disposed at a position offset from the crank pulley 102 in the direction of the central axis J1 of the pulley 100. Therefore, the transmission belt 101 is extended between the belt tensioner pulley 100 and the crank pulley 102 in a state where the transmission belt 101 is inclined at a predetermined inclination angle α with respect to the radial direction orthogonal to the central axis J1 and the central axis J2. It will be. The shape of the belt tensioner and the attachment position to the internal combustion engine are designed so that the inclination angle α of the transmission belt 101 does not become excessively large.

  However, the inclination angle α of the transmission belt 101 may be larger than the designed angle due to an assembly error of each member constituting the belt tensioner and an error in the attachment position of the belt tensioner with respect to the internal combustion engine. If the inclination angle α of the transmission belt 101 becomes excessively large, an excessive force may be applied to the transmission belt 101, or abnormal noise may be generated when the transmission belt 101 circulates.

  In order to solve the above problems, the present invention provides a support member attached to an internal combustion engine, a connecting shaft extending from the supporting member, and an arm member rotatable relative to the supporting member about a central axis of the connecting shaft. And a pulley rotatably attached to said arm member, wherein an annular disc spring intervenes between said support member and said arm member, and said disc spring The connecting shaft is inserted through the arm member, and the arm member is provided with an insertion hole through which the connecting shaft is inserted, and the connecting shaft has a flange projecting radially outward of the connecting shaft. A portion is provided, and the flange portion is located on the opposite side of the support member with respect to the arm member in the axial direction of the connection shaft, and the connection is made with the inner circumferential surface of the insertion hole A cylindrical first bush is interposed between the outer peripheral surface of the first bush, and the radial thickness of the first bush increases toward the center side in the central axis direction of the first bush. An annular second bush is interposed between the flange portion and the arm member, and the connection shaft is inserted through the second bush, and the thickness of the second bush in the central axial direction is The smaller the second bush is, the more outward it goes in the radial direction.

  According to the above configuration, a gap is generated between the inner circumferential surface of the insertion hole in the arm member and the outer circumferential surface of the connecting shaft at both end portions in the central axis direction of the first bush. Therefore, the arm member can be tilted so that the central axis of the insertion hole in the arm member is inclined with respect to the central axis of the connecting shaft. Further, since the thickness of the second bush on the outer side in the radial direction is small, the second bush does not hinder the tilting operation of the arm member. If the arm member tilts in this way, the pulley can also tilt with the arm member. Therefore, even if an error occurs when the arm member or the pulley is assembled, or an error occurs in the attachment position of the belt tensioner with respect to the internal combustion engine, the error can be absorbed by the tilting of the pulley. Therefore, it is possible to suppress an excessive increase in the inclination angle of the transmission belt hung between the pulleys due to these errors.

1 is a schematic side view of an internal combustion engine to which a belt tensioner is attached. The top view of a belt tensioner. 3. Line 3-3 in FIG. 2 sectional drawing. Sectional drawing of the belt tensioner in the state which the arm member tilted. Explanatory drawing which shows the extension direction of the transmission belt wound around the pulley of a belt tensioner. Explanatory drawing which shows the extension direction of the transmission belt wound around the pulley of the conventional belt tensioner.

  Hereinafter, embodiments of the present invention will be described. First, the relationship between various pulleys of the internal combustion engine 10 and the belt tensioner 20 will be described. In the following description, it is assumed that the belt tensioner 20 is attached to the internal combustion engine 10, and the direction of the belt tensioner 20 is described based on the direction of the internal combustion engine 10.

  As shown in FIG. 1, one end of a crankshaft 11 protrudes from the side surface of the internal combustion engine 10. A substantially disk-like crank pulley 12 is fixed to one end of the crankshaft 11. The center of the crank pulley 12 is located on the central axis of the crankshaft 11, and the crank pulley 12 rotates integrally as the crankshaft 11 rotates.

  From the side surface of the internal combustion engine 10, one end of the first input shaft 13A protrudes. A substantially disc-shaped first auxiliary pulley 14A is fixed to one end of the first input shaft 13A. The center of the first accessory pulley 14A is located on the central axis of the first input shaft 13A. When the direction perpendicular to both the vertical direction and the axial direction of the crankshaft 11 (thickness direction in the drawing of FIG. 1) is the width direction of the internal combustion engine 10, the first accessory pulley 14A is one side of the crank pulley 12 in the width direction. It is located on the side (right side in FIG. 1).

  In addition to the first input shaft 13A, one end of a second input shaft 13B and one end of a third input shaft 13C protrude from the side surface of the internal combustion engine 10. Similar to the first input shaft 13A, a substantially disk-shaped second auxiliary pulley 14B and third auxiliary pulley 14C are fixed to one end of the second input shaft 13B and one end of the third input shaft 13C. . The second auxiliary pulley 14B is located on the upper side of the first auxiliary pulley 14A, and the third auxiliary pulley 14C is located on the other side in the width direction of the second auxiliary pulley 14B (left side in FIG. 1).

  Note that auxiliary devices that operate with the rotation of the crankshaft 11 as a drive source are drivingly connected to the first input shaft 13A, the second input shaft 13B, and the third input shaft 13C. For example, an oil pump for pumping engine oil for lubrication to various parts of the internal combustion engine 10, a cooling water pump for pumping cooling water to the water jacket of the internal combustion engine 10, rotational torque of the crankshaft 11 Examples include a power generation motor (motor generator) that converts electric power, a compressor for an air conditioner, and the like.

  On the side surface of the internal combustion engine 10, a substantially disc-like idler pulley 15 is disposed between the second accessory pulley 14B and the third accessory pulley 14C. The idler pulley 15 is rotatably attached to the internal combustion engine 10 via the rotation shaft 16.

  On the side surface of the internal combustion engine 10, a belt tensioner 20 is disposed between the crank pulley 12 and the first accessory pulley 14A. The belt tensioner 20 includes a tensioner pulley 40, which is located above the crankshaft 11.

  The crank pulley 12, the first auxiliary pulley 14A, the second auxiliary pulley 14B, and the third auxiliary pulley 14C have an annular (endless) transmission for transmitting the rotational torque of the crank pulley 12 to other pulleys. The belt 50 is wound around. As a whole, the transmission belt 50 is wound around the crank pulley 12, the first accessory pulley 14A, the second accessory pulley 14B, and the third accessory pulley 14C from the outside.

  The transmission belt 50 is wound around the lower side of the idler pulley 15 between the second accessory pulley 14B and the third accessory pulley 14C. The transmission belt 50, the second auxiliary pulley 14 </ b> B, and the third auxiliary pulley 15 </ b> B are pressed down by the idler pulley 15 on the transmission belt 50 between the second auxiliary pulley 14 </ b> B and the third auxiliary pulley 14 </ b> C. Adhesiveness with the auxiliary machine pulley 14C is ensured.

  The transmission belt 50 is wound around the tensioner pulley 40 of the belt tensioner 20 between the third accessory pulley 14 </ b> C and the crank pulley 12. When viewed from the side of the third auxiliary pulley 14C, the transmission belt 50 is wound from the other side in the width direction of the third auxiliary pulley 14C to one side in the width direction of the tensioner pulley 40, and then the width of the crank pulley 12 is reached. It is hung to the other side in the direction. The tension of the entire transmission belt 50 is adjusted by changing the position of the tensioner pulley 40 of the belt tensioner 20.

  In this embodiment, the crankshaft 11, the first input shaft 13A, the second input shaft 13B, and the third input shaft 13C extend in parallel to one another. That is, the rotation center axes of the crank pulley 12, the first accessory pulley 14A, the second accessory pulley 14B, and the third accessory pulley 14C are parallel to one another.

Next, the belt tensioner 20 will be described more specifically.
As shown in FIG. 2, the belt tensioner 20 includes a plate-like support member 21 attached to the internal combustion engine 10. The support member 21 extends substantially in an L shape when seen in a plan view. In this embodiment, the support member 21 includes a laterally extending portion 21a that extends substantially in the width direction of the internal combustion engine 10, and a longitudinally extending portion 21b that extends upward from one end in the width direction of the laterally extending portion 21a. It consists of

  The bolt holes 22 pass through in the thickness direction at both ends of the laterally extending portion 21a. The support member 21 (belt tensioner 20) is attached to the internal combustion engine 10 by inserting a bolt (not shown) into the bolt holes 22.

  As shown in FIG. 3, a shaft hole 23 having a circular shape in plan view penetrates in the thickness direction at the upper end portion of the vertically extending portion 21b. A shaft portion 24 a of the connecting shaft 24 is fitted in the shaft hole 23. The shaft portion 24 a of the connecting shaft 24 has a cylindrical shape, and the outer diameter thereof is substantially the same as the inner diameter of the shaft hole 23 in the longitudinally extending portion 21 b. One end in the axial direction of the shaft portion 24 a is fitted into the shaft hole 23 in the vertically extending portion 21 b. Most of the shaft portion 24a extends from the vertically extending portion 21b toward the internal combustion engine 10 side (right side in FIG. 3).

  From the outer peripheral surface of the end portion of the shaft portion 24a on the internal combustion engine 10 side (the end portion opposite to the support member 21), a flange portion 24b protrudes outward in the radial direction of the shaft portion 24a. The flange portion 24 b extends over the entire circumferential direction of the shaft portion 24 a.

  A plate-like arm member 25 is connected to the longitudinally extending portion 21 b of the support member 21 via a connecting shaft 24. The arm member 25 has a rectangular shape in plan view as a whole. In this embodiment, the arm member 25 is slightly curved in its longitudinal direction. The arm member 25 is composed of a thick portion 25a constituting substantially one half in the longitudinal direction and a thin portion 25b constituting substantially the other half in the longitudinal direction.

  In the thick portion 25 a of the arm member 25, the insertion hole 26 having a circular shape in a plan view penetrates in the thickness direction of the thick portion 25 a. The central axis A2 of the insertion hole 26 extends parallel to the crankshaft 11 when the belt tensioner 20 is attached to the internal combustion engine 10 without error. The inner diameter of the insertion hole 26 is larger than the outer diameter of the shaft portion 24 a of the connecting shaft 24 and smaller than the outer diameter of the flange portion 24 b. The shaft portion 24 a of the connecting shaft 24 is inserted into the insertion hole 26 in the thick portion 25 a. Further, in a state where the shaft portion 24 a of the connecting shaft 24 is inserted into the insertion hole 26, the flange portion 24 b of the connecting shaft 24 is positioned closer to the internal combustion engine 10 than the thick portion 25 a (opposite to the support member 21). doing. Therefore, the arm member 25 is rotatable relative to the support member 21 about the central axis A1 of the connecting shaft 24. Further, the arm member 25 is prevented from coming off toward the internal combustion engine 10 due to the presence of the flange portion 24 b of the connecting shaft 24.

  The thin-walled portion 25b of the arm member 25 has a thickness which is about one third of that of the thick-walled portion 25a. In this embodiment, the surface of the thin portion 25b on the side of the internal combustion engine 10 is flush with the surface of the thick portion 25a on the side of the internal combustion engine 10. That is, in the arm member 25, a step between the thick portion 25a and the thin portion 25b exists on the surface on the support member 21 side.

  A cylindrical rotating shaft 27 protrudes from the surface on the support member 21 side in the thin portion 25b. The central axis A3 of the rotation shaft 27 is parallel to the central axis A2 of the insertion hole 26. An annular ball bearing 28 is fitted on the outer peripheral surface of the rotating shaft 27. An annular tensioner pulley 40 is attached to the outer peripheral surface of the annular ball bearing 28. The outer circumferential surface of the tensioner pulley 40 is a circumferential surface centered on the central axis A3 of the rotating shaft 27, and the transmission belt 50 described above is wound around the outer circumferential surface. The tensioner pulley 40 is rotatable relative to the arm member 25 about the central axis A3 of the rotary shaft 27 via the ball bearing 28. In FIG. 2, the internal structure of the ball bearing 28 is not shown.

  As shown in FIG. 2, a plate-like spring receiver 29 protrudes from the thick portion 25 a of the arm member 25 toward the other side in the width direction of the internal combustion engine 10. The spring receiver 29 has a substantially square shape in plan view. One end of a coil spring S is fixed to the surface of the spring receiver 29 on the internal combustion engine 10 side. The other end of the coil spring S is fixed to the laterally extending portion 21 a of the support member 21. When the arm member 25 tries to turn to the coil spring S side (counterclockwise direction in FIG. 2), the coil spring S exerts an urging force in a direction (clockwise direction in FIG. 2) against the movement. give. In FIG. 3, the coil spring S is not shown.

  As shown in FIG. 3, an annular member 31 is interposed between the support member 21 (vertically extending portion 21 a) and the arm member 25 (thick portion 25 b) in the direction of the central axis A <b> 1 of the connecting shaft 24. ing. The shaft portion 24 a of the connecting shaft 24 is inserted into the central hole of the annular member 31. The annular member 31 is made of a synthetic resin and has a certain degree of flexibility.

  Further, a disc spring 32 made of metal is interposed between the support member 21 and the arm member 25 and closer to the support member 21 than the annular member 31. The disc spring 32 has an annular shape in a plan view, and a shaft portion 24 a of the connecting shaft 24 is inserted through a central hole thereof. The disc spring 32 is shaped such that the inner peripheral portion is recessed to one side in the axial direction with respect to the outer peripheral portion. The disc spring 32 is arranged so that the outer peripheral portion faces the arm member 25 side and the inner peripheral portion faces the support member 21 side.

  A cylindrical first bush 35 is interposed between the inner peripheral surface of the insertion hole 26 and the outer peripheral surface of the shaft portion 24 a of the connecting shaft 24. The dimension in the central axis direction of the first bush 35 is substantially the same as the dimension in the direction of the central axis A2 of the insertion hole 26 (the thickness of the thick portion 25a). The first bush 35 is disposed so as not to protrude from the insertion hole 26 in the direction of the central axis A2 of the insertion hole 26.

  The outer diameter of the first bush 35 is substantially the same as the inner diameter of the insertion hole 26 throughout the central axial direction of the first bush 35. Further, the inner diameter of the first bush 35 is smaller as it goes from the both ends in the central axis direction of the first bush 35 toward the center. As a result, the thickness in the radial direction of the first bush 35 is larger toward the center in the central axis direction. The inner diameter of the first bush 35 in the center axis direction center is substantially the same as the outer diameter of the shaft portion 24 a of the connecting shaft 24. That is, the first bush 35 is in contact with the outer peripheral surface of the shaft portion 24 a at the center in the central axis direction. In this embodiment, the inner peripheral surface of the first bush 35 is a curved surface extending in an arc shape in a cross section along the central axis direction. The material of the first bush 35 is a synthetic resin.

  In the direction of the central axis A2 of the insertion hole 26, an annular second bush 36 is interposed between the thick portion 25a of the arm member 25 and the flange portion 24b of the connecting shaft 24. The shaft portion 24 a of the connecting shaft 24 is inserted into the central hole of the second bush 36. The inner diameter of the second bush 36 is substantially the same as the inner diameter of the insertion hole 26. Further, the outer diameter of the second bush 36 is substantially the same as the outer diameter of the flange portion 24 b of the connecting shaft 24.

  The surface of the second bush 36 on the side of the flange portion 24b (the side of the internal combustion engine 10) is a flat surface, and is in surface contact with the flange portion 24b. The thickness of the second bush 36 in the central axis direction is smaller toward the outer side in the radial direction of the second bush 36. In this embodiment, the surface of the second bush 36 on the side of the arm member 25 is a curved surface extending in an arc shape in the radial cross section of the second bush 36. The material of the second bush 36 is a synthetic resin. In this embodiment, since the arm member 25 is biased toward the internal combustion engine 10 by the disc spring 32, the radially inner portion of the second bushing 36 contacts the surface of the arm member 25 on the internal combustion engine 10 side. I am in touch.

The operation and effects of the present embodiment will be described.
As shown in FIG. 3, the arm member 25 is biased toward the internal combustion engine 10 with respect to the support member 21 by a disc spring 32. Further, the urging force from the disc spring 32 acts on the arm member 25 substantially uniformly over the entire circumferential direction of the central axis A <b> 2 of the insertion hole 26. Therefore, if no force in the direction of the rotation axis A3 acts on the tensioner pulley 40, the central axis A2 of the insertion hole 26 in the arm member 25 is substantially parallel to the central axis A1 of the connecting shaft 24.

  In the belt tensioner 20 of the present embodiment, the thickness of both ends in the axial direction of the first bush 35 is small, the inner peripheral surface of the both ends in the axial direction of the first bush 35, and the outer peripheral surface of the connecting shaft 24. There is a gap between the Therefore, if a corresponding force acting on the tensioner pulley 40 toward the internal combustion engine 10 in the direction of the central axis A1 of the connecting shaft 24 acts, the disc spring 32 is elastically deformed, and the tensioner pulley 40 is moved toward the internal combustion engine 10. The arm member 25 is tilted so as to be positioned. As a result, as shown in FIG. 4, the central axis A <b> 2 of the insertion hole 26 in the arm member 25 is inclined with respect to the central axis A <b> 1 of the connecting shaft 24. As shown in FIG. 3, the central axis A3 of the rotation shaft 27 of the tensioner pulley 40 is parallel to the central axis A2 of the insertion hole 26. Therefore, the rotation of the tensioner pulley 40 as the arm member 25 tilts. The central axis A3 of the shaft 27 is also inclined with respect to the central axis A1 of the connecting shaft 24.

  At this time, as shown in FIG. 4, a part of the surface on the side of the internal combustion engine 10 in the arm member 25 (thick portion 25 a) is smaller in distance from the flange portion 24 b in the connecting shaft 24. Specifically, in the example shown in FIG. 4, the upper portion shown in FIG. 4 is the flange portion 24 b of the connecting shaft 24 on the surface of the arm member 25 on the internal combustion engine 10 side and around the opening of the insertion hole 26. Get close. In this respect, in the present embodiment, the thickness on the radially outer side of the second bush 36 is small. Therefore, even if the arm member 25 tilts and the distance to the flange portion 24 b decreases as in the above example, the radially outer portion of the second bush 36 does not interfere with the arm member 25. That is, the second bushing 36 does not hinder the tilting of the arm member 25, and the tilting of the arm member 25 is performed smoothly.

  As described above, when the force in the direction of the central axis A1 of the connecting shaft 24 acts on the tensioner pulley 40, the rotary shaft 27 of the tensioner pulley 40 can be inclined within a certain range. When the force in the direction of the central axis A1 of the connecting shaft 24 is reduced on the tensioner pulley 40, the tilting of the arm member 25 is canceled by the elastic return force of the disc spring 32, and the central axis of the insertion hole 26 in the arm member 25 is eliminated. A 2 coincides with the central axis A 1 of the connecting shaft 24.

  Here, as schematically shown in FIG. 5, in the direction of the central axis A1 of the connecting shaft 24 (a direction parallel to the central axis A3 of the rotation shaft 27 of the tensioner pulley 40 when the arm member 25 is not tilted) It is assumed that the position of the crank pulley 12 is shifted with respect to the position of the tensioner pulley 40. In this case, the transmission belt 50 is diagonally wound between the tensioner pulley 40 and the crank pulley 12. Therefore, a force in the direction to cancel the inclination of the transmission belt 50, that is, a force in the direction of the central axis A1 of the connecting shaft 24 acts on the tensioner pulley 40. As a result, as described above, the arm member 25 tilts, and the tensioner pulley 40 tilts accordingly. By tilting the tensioner pulley 40 in this way, the inclination angle α of the transmission belt 50 with respect to the radial direction orthogonal to the central axis J2 of the crank pulley 12 becomes smaller than when the tensioner pulley 40 cannot tilt.

  By the way, for example, an attachment error of the support member 21 with respect to the internal combustion engine 10 or an assembly error of the arm member 25 with respect to the support member 21 occurs, and the inclination angle α of the transmission belt 50 becomes slightly larger than the designed inclination angle. There is. In this respect, the inclination angle α of the transmission belt 50 in the present embodiment is correspondingly smaller than the inclination angle α of the transmission belt 50 when the arm member 25 can not be tilted. Therefore, even when the inclination angle α of the transmission belt 50 is slightly larger than the designed inclination angle due to the error as described above, the inclination angle α of the transmission belt 50 is such that the arm member 25 cannot tilt. The inclination angle α of the transmission belt 50 is not excessively increased. In other words, the increase in the inclination angle α of the transmission belt 50 due to the error in the mounting position and the assembling error as described above is absorbed by the inclination angle α of the transmission belt 50 being reduced because the arm member 25 can be inclined. it can. Therefore, it is possible to suppress the generation of excessive force on the transmission belt 50 due to the excessively large inclination angle α of the transmission belt 50 or the generation of abnormal noise when the transmission belt 50 rotates.

The present embodiment can be modified as follows. The present embodiment and the following modifications can be implemented in combination with one another as long as there is no technical contradiction.
-The number of auxiliary pulleys in the internal combustion engine 10 does not matter. If a plurality of pulleys including the crank pulley 12 are provided and the rotational torque of the crank pulley 12 is transmitted to other pulleys via the transmission belt 50, the number of pulleys can be changed as appropriate. Further, the idler pulley 15 may be increased, or the idler pulley 15 may be omitted.

  The position and orientation of the belt tensioner 20 can be changed as appropriate. For example, the belt tensioner 20 is disposed at a position where the idler pulley 15 in the above embodiment is provided, and the tensioner pulley 40 is disposed between the second auxiliary pulley 14B and the third auxiliary pulley 14C in the transmission belt 50. You may hang parts.

  The shapes of the support member 21 and the arm member 25 in the belt tensioner 20 can be changed as appropriate. If the support member 21 is attached to the internal combustion engine 10 and the arm member 25 is attached so that the support member 21 can rotate, for example, the shape is appropriately changed so as not to interfere with other members. It is also good.

  The configuration for applying the biasing force to the arm member 25 is not limited to the coil spring S of the above embodiment. For example, a torsion spring that applies a biasing force in the radial direction about the central axis A <b> 1 of the connecting shaft 24 may be disposed inside the insertion hole 26 in the arm member 25 or between the arm member 25 and the support member 21. .

  The ring member 31 can be omitted depending on the material of the arm member 25 and the like. For example, if the material of the arm member 25 is a synthetic resin and noise and the like are unlikely to occur due to the friction with the disc spring 32, no problem occurs even if the annular member 31 is omitted.

  The disc spring 32 may be disposed such that the inner peripheral portion faces the arm member 25 side and the outer peripheral portion faces the support member 21 side. However, depending on the elasticity of the disc spring 32 and the size of the disc spring 32 with respect to the inner diameter of the insertion hole 26, as in the above embodiment, the arm of the disc spring 32 facing the arm member 25 is the arm The posture of the member 25 tends to be stable.

  The disc spring 32 is not limited to an annular shape in plan view. For example, the disc spring 32 may be configured by an annular portion in an annular shape in plan view and a claw portion radially projecting from the annular portion. Even with such a configuration, three or more claws of the disc spring 32 may be disposed in the circumferential direction, and the arm member 25 may be uniformly biased in the circumferential direction as a whole.

  The dimension of the first bush 35 in the central axis direction may be smaller than the dimension of the insertion hole 26 in the central axis A2 direction. When the dimension in the central axis direction of the first bush 35 is smaller than the dimension in the central axis A2 direction of the insertion hole 26, the first bush 35 is disposed at the center in the central axis A2 direction inside the insertion hole 26. Although it is preferable, it may be disposed slightly offset in the direction of the central axis A2.

  In the above embodiment, the outer diameter of the first bush 35 is constant throughout the central axial direction of the first bush 35, but the present invention is not limited to this. For example, the outer diameter of the first bush 35 may be smaller as it goes from the both ends in the central axis direction of the first bush 35 toward the center. In the case of this modification, the inner diameter of the first bush 35 may be made substantially the same as the outer diameter of the connecting shaft 24 throughout the central axial direction of the first bush 35. Even in such a configuration, the thickness in the radial direction of the first bush 35 becomes larger toward the center of the first bush 35 in the central axis direction.

  In the above embodiment, the surface of the second bush 36 on the side of the flange portion 24b is flat, but the surface of the second bush 36 on the side of the arm member 25 (the opposite side to the internal combustion engine 10) is flat. It may be a In the case of this modification, the thickness of the second bush 36 in the central axis direction is obtained by making the surface on the flange 24 b side of the second bush 36 curved in a circular arc shape in the radial cross section of the second bush 36. Can be reduced toward the radially outer side of the second bush 36.

  -The material of the 1st bush 35 and the 2nd bush 36 is not restricted to a synthetic resin. For example, if a lubricant can be applied to the surfaces of the first bush 35 and the second bush 36 so as to prevent noise and the like from being generated when the arm member 25 is rotated or tilted, the first bush The material of the 35 and the second bush 36 may be a metal or the like. The lubricant in this case is not limited to the liquid oil, and may be a solid lubricant such as molybdenum disulfide.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Crankshaft, 12 ... Crank pulley, 13A ... 1st input shaft, 13B ... 2nd input shaft, 13C ... 3rd input shaft, 14A ... 1st auxiliary machine pulley, 14B ... 2nd auxiliary machine Pulley, 14C ... third auxiliary pulley, 15 ... idler pulley, 16 ... rotating shaft, 20 ... belt tensioner, 21 ... support member, 21a ... laterally extending portion, 21b ... vertically extending portion, 22 ... bolt hole, 23 ... axial hole, 24 ... connecting shaft, 24a ... shaft portion, 24b ... flange portion, 25 ... arm member, 25a ... thick-walled portion, 25b ... thin-walled portion, 26 ... insertion hole, 27 ... rotating shaft, 28 ... bearing, 29 DESCRIPTION OF SYMBOLS ... Spring acceptor, 31 ... Ring member, 32 ... Disc spring, 35 ... 1st bush, 36 ... 2nd bush, 40 ... Tensioner pulley, 50 ... Transmission belt, S ... Spring, A1 ... Center axis of a connecting shaft, A2 ... central axis of insertion hole , A3 ... rotary shaft of the central axis 100 ... belt tensioner pulley, 101 ... transmission belt, 102 ... crank pulley, J1 ... center axis, J2 ... central axis.

Claims (1)

A support member attached to an internal combustion engine, a connecting shaft extending from the support member, an arm member rotatable relative to the support member about a central axis of the connecting shaft, and a member rotatable relative to the arm member A belt tensioner comprising a pulley to be attached,
An annular disc spring is interposed between the support member and the arm member, and the connecting shaft is inserted through the disc spring,
The arm member is provided with an insertion hole through which the connecting shaft is inserted,
The connecting shaft is provided with a flange portion that protrudes radially outward of the connecting shaft,
The flange portion is located on the side opposite to the support member with respect to the arm member in the axial direction of the connection shaft.
A cylindrical first bush is interposed between the inner peripheral surface of the insertion hole and the outer peripheral surface of the connecting shaft,
The thickness in the radial direction of the first bush is larger toward the central axial direction center side of the first bush,
An annular second bush is interposed between the flange portion and the arm member, and the connecting shaft is inserted through the second bush,
The belt tensioner according to claim 1, wherein a thickness of the second bush in a central axis direction is smaller toward a radially outer side of the second bush.