TWI625481B - Automatic tensioner - Google Patents

Abstract

The present invention relates to an automatic tensioner comprising: a base having a cylindrical portion; a rotary member rotatably supported relative to the base; and a pulley rotatably disposed on the above a rotating member; the friction member is sandwiched between the inner circumferential surface of the cylindrical portion and the rotating member in a radial direction of the cylindrical portion; and the coil spring has one end locked to the friction member and the other end The susceptor is locked to the susceptor, and the frictional member is placed in a state of being compressed in the axial direction of the cylindrical portion, and the friction member is pressed against the slewing member in the axial direction, and the slewing member is coupled via the friction member. The pedestal is energized in one direction; the friction member includes: a circular arc surface slidably contacting along an inner circumferential surface of the cylindrical portion; and a first locking portion in a circumferential direction of the cylindrical portion The upper portion is located on the one side of the circular arc surface and locked to the rotating member; and the second locking portion is locked to the one end of the coil spring.

Description

Automatic tensioner

The present invention relates to an automatic tensioner for automatically and moderately maintaining the tension of a belt.

For example, in a belt driven by an auxiliary machine for an automobile engine, the belt tension changes due to a rotation change caused by engine combustion. Therefore, the variation of the belt tension causes the belt to slip, which causes problems such as the sliding sound or the wear of the belt. In order to solve this problem, an automatic tensioner has been used as a mechanism for suppressing the occurrence of belt slip even if the belt tension fluctuates.

For example, the automatic tensor of Patent Document 1 includes a susceptor having a first cylindrical portion and a rotator member having a second cylindrical portion disposed inside the first cylindrical portion and rotatably with respect to the susceptor Freely supported, and can be mounted with a pulley for the winding belt; a coil spring disposed inside the second cylindrical portion and energizing the rotating member in one direction with respect to the base; and a friction member The first cylindrical portion and the second cylindrical portion are disposed between the first cylindrical portion and the second cylindrical portion, and are slidable on the inner circumferential surface of the first cylindrical portion, and have a convex portion that engages with a concave portion provided on the outer circumferential surface of the second cylindrical portion.

Further, the automatic tensioner of Patent Document 2 includes: a base; a rotary member that is rotatably supported relative to the base; and a coil spring that energizes the rotary member in one direction with respect to the base; a friction member disposed between the inner circumferential surface of the cylindrical portion provided on the rotary member (or the base) and the coil spring, and slidable with the inner circumferential surface of the cylindrical portion; and a leaf spring coupled to the plate spring Friction member, and one end is clamped to the rotating member (or base) and the disk in the circumferential direction Between the ends of the spring.

As in the case of the increase and decrease of the belt tension of the automatic tensioner of Patent Documents 1 and 2, the frictional force generated on the sliding surface of the friction member is different, and has an asymmetrical attenuation according to the direction of rotation of the rotating member. Characteristics (asymmetric damping characteristics). That is, when the belt tension is increased, a large frictional force can be generated, and the swing of the rotating member is sufficiently attenuated, and a small frictional force is generated when the belt tension is reduced, so that the swirling can be performed. The member changes in accordance with the tension of the belt.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-118668

[Patent Document 2] Japanese Patent No. 5276520

However, in the automatic tensor of Patent Document 1, the second cylindrical portion of the slewing member and the friction member are disposed between the first cylindrical portion of the susceptor and the coil spring, and are also inside the second cylindrical portion. Since the circumferential surface and the friction member are formed with the uneven shape that is engaged with each other, there is a problem that the automatic tensioner is enlarged in the radial direction. Further, since the second cylindrical portion contains a metal material, there is also a problem that the automatic tensioner becomes heavy.

Further, in the automatic tensioner of Patent Document 2, the thickness of the leaf spring and the friction member disposed between the cylindrical portion of the rotary member (or the base) and the coil spring is relatively thin, so that the radial direction can be suppressed. The size is increased or the weight is increased, but since the number of parts is large, there is a problem that assembly takes time.

Accordingly, it is an object of the present invention to provide an automatic tensioner having a small number of parts, a light weight, and a small size having asymmetric damping characteristics.

An automatic tensioner according to a first aspect of the present invention includes: a base having a cylindrical portion; a moving member rotatably supported with respect to the base; a pulley rotatably provided to the rotating member; and a friction member sandwiched between the cylindrical portion in a radial direction of the cylindrical portion And a coil spring, wherein one end of the coil spring is locked to the friction member, and the other end is locked to the base, and is disposed on the shaft in a state where the cylindrical portion is compressed in the axial direction. Pressing the friction member upward against the rotating member, and energizing the rotating member to the base in one direction via the friction member; and the friction member includes: a circular arc surface, which can be along The inner peripheral surface of the cylindrical portion slides; the first locking portion is located on the one side of the circular arc surface in the circumferential direction of the cylindrical portion, and is locked to the rotary member; 2 a locking portion that is locked to the one end of the coil spring.

In the first aspect of the automatic tension device according to the second aspect of the present invention, the second locking portion of the friction member is located radially outward of the first locking portion, and is longer in the circumferential direction. The first locking portion is further on the opposite side to the one direction.

In the first or second aspect of the automatic tension device according to the third aspect of the present invention, the friction member includes a first component and a second component having a surface hardness higher than that of the first component, and the first component constitutes the arc And a surface of the friction member that is continuous with the arcuate surface and that is in contact with the rotatable member in the axial direction, wherein the second component constitutes the first locking portion and the second locking portion.

In a third aspect of the automatic tension device according to the fourth aspect of the present invention, the first component and the second component are configured to mesh with each other in the circumferential direction.

In any one of the first to fourth aspects of the automatic tension device according to the fifth aspect of the present invention, the one end of the coil spring has an arc shape.

In any one of the first to fourth aspects of the automatic tension device according to the sixth aspect of the present invention, the one end of the coil spring includes an arcuate portion and a linear portion.

In any one of the first to sixth aspects of the automatic tension device according to the seventh aspect of the present invention, the base has a pedestal portion provided inside an end portion of the cylindrical portion, and the pedestal The portion includes: an end holding device that holds the other end portion of the coil spring; and a posture supporting device that supports the first end region of the other end side of the coil spring in the axial direction and the radial direction The portion held by the end holding means is closer to the one end side.

In any one of the first to seventh aspects of the automatic tension device according to the eighth aspect of the present invention, the first locking portion is oriented toward the one direction side as it goes radially outward. tilt.

In any one of the first to seventh aspects of the automatic tension device according to the ninth aspect of the present invention, the first locking portion is opposed to the side opposite to the one direction as it goes radially outward. Tilt in the radial direction.

According to the first aspect of the present invention, when the rotation member is rotated by the pressing force of the coil spring by the increase in the belt tension, the arcuate surface of the friction member is opposed to the inner circumference of the cylindrical portion of the base. The surface slides to generate a frictional force between the arcuate surface of the friction member and the inner peripheral surface of the cylindrical portion of the base. The arcuate surface of the friction member is located further in the circumferential direction than the first locking portion of the friction member in the direction opposite to the direction in which the coil spring is energized (the one direction), that is, on the side of the rotation direction of the rotary member. Therefore, the force that the first locking portion of the friction member receives from the rotation member can be used as a force for pressing the arcuate surface of the friction member against the inner circumferential surface of the cylindrical portion of the base. Therefore, a large frictional force can be generated between the circular arc surface of the friction member and the inner circumferential surface of the cylindrical portion of the base, so that a large damping force such as a sufficient attenuation of the swing of the rotary member can be generated.

On the contrary, when the rotation member is rotated by the pressing force of the coil spring by reducing the belt tension, the friction member is subjected to the circumferential direction from the coil spring, but due to the circular surface of the friction member The first locking portion of the friction member is located on the side opposite to the direction of the rotation of the coil spring in the circumferential direction, so that the arc of the friction member is not applied by the pressing force in the circumferential direction of the coil spring. The surface is pressed against the inner circumferential surface of the cylindrical portion of the base, thereby The frictional force between the arcuate surface of the friction member and the inner peripheral surface of the cylindrical portion of the base is suppressed. Therefore, a small frictional force can be generated between the circular arc surface of the friction member and the inner circumferential surface of the cylindrical portion of the base, and the swing of the rotary member can sufficiently follow the reduction of the belt tension.

Further, since the automatic tensioner of the present invention can realize the above-described asymmetrical damping characteristic only by the friction member and the coil spring, it is lightweight and has a small number of parts and is easy to assemble. Further, since one end of the coil spring is locked to the friction member that is sandwiched between the cylindrical portion of the base and the rotary member in the radial direction, it is not necessary to ensure a large space between the coil spring and the cylindrical portion of the base. The space allows the automatic tensioner to be miniaturized.

According to the second aspect of the present invention, since the arcuate surface of the friction member is formed on the side opposite to the rotation enabling direction (the one direction) of the coil spring from the first locking portion, the second locking portion is also The first locking portion is formed on the side opposite to the direction in which the rotation of the coil spring is opposite to the first locking portion, and thus the first locking portion is formed in the circumferential direction of the second locking portion. The friction member can be miniaturized in the circumferential direction.

According to the third aspect of the present invention, the first locking portion and the second locking portion include the second member having a relatively high surface hardness, so that the force acting on the first locking portion and the second locking portion is accompanied When the belt tension is increased and the tension is increased, damage (deformation or depression) of the first locking portion and the second locking portion can be prevented. Further, since the first locking portion and the second locking portion can be prevented from being damaged, it is possible to cope with a high-load driving system that requires a large belt tension and to reduce the size of the friction member. Further, the first part constitutes an arc surface and a surface of the friction member that is in contact with the rotation member in the axial direction, which is continuous with the arc surface, and can prevent falling off in the axial direction.

According to the fourth configuration of the present invention, even if the first member and the second member are not attached by an adhesive or fixed by a rivet, they can be arranged so as not to be movable in the circumferential direction, and can be easily assembled.

According to the fifth aspect of the present invention, since one end of the coil spring does not have a linear portion, the length of the coil spring can be shortened accordingly, so that the size of the second locking portion can be reduced, thereby making it possible to reduce the size of the second locking portion. The friction member is miniaturized in the circumferential direction. Further, by shortening the length of the coil spring and miniaturizing the circumferential direction of the friction member, it is possible to further reduce the weight of the automatic tensioner. Further, since it is not necessary to process one end of the coil spring or the like, simplification of the manufacturing steps and reduction in manufacturing cost can be achieved.

According to the sixth aspect of the present invention, the size of the second locking portion is larger than when the one end of the coil spring includes only the arc-shaped portion or the portion including only the linear portion, so that the arc can be secured. The area of the surface is large, and the wear of the circular surface can be suppressed.

According to the seventh aspect of the present invention, the portion of the first loop region on the other end side of the coil spring that is held by the end holding member on the one end side is in the axial direction by the posture supporting device. Supported in the radial direction, the coil spring can be stably twisted and deformed.

According to the eighth configuration of the present invention, the assembly of the friction member is easy.

According to the ninth configuration of the present invention, it is possible to more reliably prevent the friction member from coming out in the circumferential direction when the belt tension is reduced.

1‧‧‧Automatic tensioner

2‧‧‧Base

3‧‧‧Rotating components

4‧‧‧ pulley

5‧‧‧ coil spring

6‧‧‧ Friction members

7‧‧‧ bearing

8‧‧‧Axis

9‧‧‧Spring containment room

20‧‧‧Deputy Department

21‧‧‧Outer tube (cylinder)

22‧‧‧Inner tube

23‧‧‧ Keeping the slot (end holding device)

24‧‧‧ posture support (posture support device)

24a‧‧‧ axial support surface

24b‧‧‧radial support surface

25‧‧‧Position Support (Pose Support Device)

25a‧‧‧ axial support surface

30‧‧‧Disc

30a‧‧‧ring groove

31‧‧‧Protruding

31a‧‧‧ card stop

31b‧‧‧Contact surface

32‧‧‧Pulley Support

60‧‧‧ arc surface

61‧‧‧ card stop (first stop)

62‧‧‧ side

63‧‧‧ side

64‧‧‧ Holding groove (2nd locking part)

100‧‧‧ engine body

101‧‧‧Drive belt

203‧‧‧Rotating components

208‧‧‧Axis

231‧‧‧Protruding

306‧‧‧ Friction members

306x‧‧‧Part 1

306y‧‧‧Part 2

405‧‧‧ coil spring

464‧‧‧ Keeping the groove (2nd locking part)

505‧‧‧ coil spring

505a‧‧‧Arc-shaped part

505b‧‧‧linear part

564‧‧‧Retaining groove (2nd locking part)

606‧‧‧Friction components

631‧‧‧ Highlights

631a‧‧‧ card stop

661‧‧‧ card stop (first stop)

A‧‧‧ arrow

B‧‧‧ arrow

Fa‧‧‧ force

Fr‧‧‧heli

Fs‧‧‧Resilience

Fs1‧‧‧

Fs2‧‧‧

R‧‧‧ axis

S‧‧‧ Section

Part T‧‧‧

X‧‧‧ direction

Fig. 1 is a cross-sectional view showing an automatic tension device according to a first embodiment of the present invention.

Figure 2 is a cross-sectional view taken along line A-A of Figure 1.

3 is a partial cross-sectional view of FIG. 2, FIG. 3(a) is a cross-sectional view taken along line D-D of FIG. 2, and FIG. 3(b) is a cross-sectional view taken along line E-E of FIG.

Figure 4 is a cross-sectional view taken along line B-B of Figure 1.

Fig. 5 is a view for explaining the force acting on the friction member when the belt tension is changed, and Fig. 5(a) is a view showing the force acting on the friction member when the belt tension is increased, and Fig. 5(b) is shown on the belt. A diagram of the force acting on the friction member when the tension is reduced.

Fig. 6 is a cross-sectional view corresponding to Fig. 1 of the automatic tension device according to the second embodiment of the present invention.

Figure 7 is a cross-sectional view corresponding to Figure 1 of the automatic tensioner according to the third embodiment of the present invention.

Figure 8 is a cross-sectional view taken along line B-B of Figure 7.

Fig. 9 is a cross-sectional view taken along line B-B of Fig. 7 in a modification of the third embodiment of the present invention.

Fig. 10 is a cross-sectional view corresponding to Fig. 4 of the automatic tension device according to the fourth embodiment of the present invention.

Figure 11 is a cross-sectional view corresponding to Figure 4 of the automatic tensioner according to the fifth embodiment of the present invention.

Figure 12 is a cross-sectional view corresponding to Figure 4 of the automatic tensioner according to the sixth embodiment of the present invention.

Next, an embodiment of the present invention will be described. In the present embodiment, the present invention is applied to an automatic tensioner in which the slack side tension of the drive belt 101 that drives the auxiliary machine of the automobile engine is kept constant.

The automatic tension device of the present embodiment is used in an auxiliary machine drive system that spans a drive pulley (not shown) that is coupled to a crankshaft of an automobile engine, and a driven pulley that drives an auxiliary machine such as an alternator ( The drive belt is wound around the illustration). In detail, the following pulley 4 of the automatic tensioner is disposed in contact with the slack side of the drive belt. The auxiliary machine drive system transmits the rotation of the crankshaft to the driven pulley via the transmission belt, thereby driving the auxiliary machine.

As shown in Fig. 1, an automatic tensioner 1 according to a first embodiment of the present invention includes a base 2 fixed to an engine body 100 shown by a two-dot chain line in Fig. 1, and a rotary member 3 having an axis R. The center is rotatably supported with respect to the base 2; the pulley 4 is rotatably provided to the rotary member 3; the coil spring 5; and the friction member 6. Furthermore, the left direction in FIG. 1 is defined as the rear direction, and the right direction is defined as the front direction. Further, the radial direction centered on the axis R is simply defined as the radial direction, and the circumferential direction centered on the axis R is simply defined as the circumferential direction.

The susceptor 2 includes, for example, an annular pedestal portion 20 which is a metal component including an aluminum alloy casting or the like, and is fixed to the engine body 100, and an outer cylinder portion (cylindrical portion) 21 from the pedestal portion 20 The outer edge portion extends forward; and the inner tubular portion 22 extends forward from the central portion of the pedestal portion 20. Inside the inner tubular portion 22, a shaft 8 extending in the front-rear direction (axis R direction) is inserted through the bearing 7 so as to be rotatable.

A spring accommodating chamber 9 is formed between the inner protruding portion 31 and the outer tubular portion 21 of the inner tubular portion 22 and the rotary member 3 . A coil spring 5 is disposed in the spring housing chamber 9. As shown in FIGS. 2 and 4, the coil spring 5 is spirally wound in the X direction from the rear end portion (the other end) toward the front end portion (one end). 1 is a cross-sectional view taken along line C-C of FIGS. 2 and 4.

As shown in FIGS. 1 and 2, a holding groove (end holding means) 23 for holding (locking) the end portion (the other end) of the coil spring 5 is formed on the front surface of the pedestal portion 20. The coil spring 5 is bent in a direction toward the radially inner side at the rear end of the coil spring, and extends linearly from a portion on the rear end side of the curved portion. This linear portion is held in the holding groove 23. The rear end portion of the coil spring 5 is sandwiched by the both side faces of the holding groove 23 in the radial direction, and is in contact with the bottom surface of the holding groove 23.

Further, the end surface of the coil spring 5 does not abut against any member, but since the vicinity of the curved portion in the portion in which the end portion of the coil spring 5 extends linearly is held by the holding groove 23 in the radial direction, the disk can be prevented. The rear end of the spring 5 is moved by the elastic restoring force generated by the torsional deformation.

Further, on the front surface of the pedestal portion 20, two posture supporting portions (posture support members) 24 and 25 projecting forward are formed at intervals in the circumferential direction. The posture supporting portions 24 and 25 are spaced apart from the holding groove 23 in the circumferential direction, and are sequentially arranged in the X direction from the holding groove 23. As shown in Fig. 3(a), the posture supporting portion 24 has an axial support surface 24a substantially perpendicular to the axis R and a radial support surface 24b along the circumferential direction. As shown in FIG. 3(b), the posture supporting portion 25 has an axial support surface 25a that is substantially perpendicular to the axis R.

The surface of the coil spring 5 is in contact with the axial support faces 24a, 25a, and the radially outer face of the coil spring 5 centered on the axis R contacts the radial support face 24b. Therefore, the portion of the first loop region on the rear end side of the coil spring 5 that is closer to the front end portion than the portion held by the retaining groove 23 is supported by the two posture supporting portions 24, 25 in the axial direction and the radial direction. Thereby, the coil spring 5 can be stably twisted Deformation. The posture support unit 24 and the posture support unit 25 correspond to the posture support device of the present invention.

The rotary member 3 includes a disk portion 30 disposed in front of the cylindrical portion 21 outside the base 2, a protruding portion 31 extending rearward from a central portion of the disk portion 30, and a pulley support portion 32, which is self-contained One of the outer edges of the disk portion 30 is partially formed to protrude. Similarly to the susceptor 2, the oscillating member 3 is a metal member including an aluminum alloy casting or the like.

A hole extending in the front-rear direction is formed in a central portion of the disk portion 30 and the protruding portion 31, and the shaft 8 is inserted into the hole so as not to be rotatable relative thereto. Therefore, the rotary member 3 is rotatably supported via the shaft 8 with respect to the base 2.

The pulley 4 is rotatably attached to the pulley support portion 32. A drive belt 101 is wound around the pulley 4. As the tension of the drive belt 101 increases or decreases, the pulley 4 (and the rotary member 3) swings with the axis R as the swing center. In addition, in FIG. 1, the internal structure of the pulley 4 is abbreviate|omitted and it shows.

An annular groove 30a for accommodating the front end portion of the cylindrical portion 21 outside the susceptor 2 is formed in the vicinity of the outer edge of the rear surface of the disk portion 30. Further, on the rear surface of the disk portion 30, a portion radially outward of the protruding portion 31 and a radially inner portion of the annular groove 30a is formed in a flat shape perpendicular to the axis R.

The protruding portion 31 is formed in a substantially cylindrical shape. As shown in FIG. 4, a fan-shaped notch is formed in the front side portion of the protruding portion 31. Both sides of the notch in the circumferential direction are composed of a locking surface 31a and a contact surface 31b. When viewed in the direction of the axis R, the locking surface 31a intersects with a straight line passing through any point of the locking surface 31a and the axis R. That is, the locking surface 31a is inclined with respect to the radial direction. More specifically, the locking surface 31a is inclined with respect to the radial direction so as to face the X direction toward the radially outer side. Further, the contact surface 31b is inclined with respect to the radial direction so as to be opposite to the X direction as it goes toward the radially outer side.

The friction member 6 is sandwiched between the inner circumferential surface of the cylindrical portion 21 outside the base 2 and the protruding portion 31 of the rotary member 3 in the radial direction. The length of the friction member 6 in the front-rear direction is substantially the same as the length of the locking surface 31a and the contact surface 31b in the front-rear direction. The front surface of the friction member 6 is flat, and The entire face or a portion is in contact with the rear surface of the disk portion 30 of the rotary member 3.

The friction member 6 is formed of a material having high lubricity, such as a fiber, a filler, a solid lubricating material, or the like, which is blended in a synthetic resin. As the synthetic resin constituting the friction member 6, for example, a thermoplastic resin such as polyamine, polyacetal, polytetrafluoroethylene, polyphenylene sulfide or ultrahigh molecular weight polyethylene, or a thermosetting resin such as phenol can be used. Further, in the friction member 6, the front surface and the arcuate surface 60 described below may include the above materials (for example, refer to the third embodiment).

The friction member 6 has a substantially fan-shaped cross-sectional shape orthogonal to the axis R, and has a circular arc surface 60, a locking surface 61 opposed to the circular arc surface 60, and a circumferential direction. Two sides 62, 63. The circular arc surface 60 is formed to have substantially the same curvature as the inner circumferential surface of the outer tubular portion 21, and is slidably contactable along the inner circumferential surface of the outer tubular portion 21. The locking surface (first locking portion) 61 is in contact with the locking surface 31a of the protruding portion 31 of the rotary member 3. The radially inner end portion of the side faces 63 of the two side faces 62, 63 which are opposite to the X direction is in contact with the contact face 31b of the projecting portion 31 of the rotary member 3.

The locking surface 61 is located on the X direction side in the circumferential direction from the circular arc surface 60. Moreover, the locking surface 61 is inclined with respect to the radial direction so as to face the X direction side toward the radially outer side. The two side faces 62 and 63 are inclined with respect to the radial direction so as to face the side opposite to the X direction toward the radially outer side. The side surface 62 of the side faces 62 and 63 on the X direction side is substantially orthogonal to the locking surface 61.

In a state where no external force acts on the friction member 6, the length from the locking surface 61 to the circular arc surface 60 in the direction orthogonal to the locking surface 61 is slightly larger than the locking surface 31a of the spin member 3 to The inner circumferential surface of the outer tubular portion 21 of the susceptor 2 is spaced apart from the locking surface 31a. Therefore, the friction member 6 is disposed between the protruding portion 31 of the rotary member 3 and the outer tubular portion 21 of the susceptor 2 in a state of being slightly compressed in a direction substantially perpendicular to the locking surface 61.

A holding groove (second locking portion) 64 that holds (locks) the front end portion (one end) of the coil spring 5 is formed on the rear surface of the friction member 6. The front end of the coil spring 5 is bent near the front end as well as the rear end portion. The curved portion extends linearly from the portion on the front end side of the curved portion. This linear portion is held in the retaining groove 64. The holding groove 64 is located radially outward of the locking surface 61, and is located on the side opposite to the X direction from the locking surface 61 in the circumferential direction.

The coil spring 5 is disposed in a state of being compressed in the direction of the axis R (front-rear direction). Therefore, the coil spring 5 presses the friction member 6 against the rear surface of the disk portion 30 of the rotary member 3 by the elastic restoring force in the direction of the shaft R.

Further, the coil spring 5 is disposed in a state of being twisted in the diameter expansion direction. Therefore, the coil spring 5 is rotationally energized in the X direction via the friction member 6 by the elastic restoring force in the circumferential direction, that is, the tension of the transmission belt 101 is pressed against the transmission belt 101 by the pulley 4 Increase the direction of the spin and energize.

Next, the operation of the automatic tension device 1 will be described.

When the tension of the drive belt 101 is increased, the rotary member 3 is rotated in the direction of the arrow A (opposite to the X direction) shown in Fig. 5(a) against the pressing force in the circumferential direction of the coil spring 5. The friction member 6 is rotated in the direction of the arrow A from the locking surface 31a of the rotary member 3 by the force Fa, and the circular arc surface 60 of the friction member 6 slides with the inner circumferential surface of the cylindrical portion 21 outside the base 2.

The arcuate surface 60 of the friction member 6 is located on the side opposite to the X direction (the direction of the arrow A direction) in the circumferential direction from the locking surface 61 of the friction member 6. Further, in the present embodiment, the tangential direction at an arbitrary point of the locking surface 61 intersects the circular arc surface 60. The force Fa of the engagement surface 61 of the friction member 6 from the rotation member 3 is a force in the tangential direction of the engagement surface 61. Therefore, the arc surface 60 exists on a straight line from the engagement surface 61 in the direction of the force Fa. . Therefore, the force Fa that the locking surface 61 of the friction member 6 receives from the rotation member 3 can be used as a force for pressing the circular arc surface 60 of the friction member 6 against the inner circumferential surface of the cylindrical portion 21 outside the base 2.

Further, the friction member 6 receives an elastic restoring force (hereinafter referred to as "torque recovery force") Fs which is generated by twisting and deforming the coil spring 5 in the radial expansion direction. The torsional restoring force Fs is the resultant force of the component force Fs1 in the X direction and the component force Fs2 in the direction of the diameter reduction.

Therefore, the resultant force Fr of the self-rotating member 3 subjected to the force Fa and the torsional restoring force Fs of the coil spring 5 is Fr Acts on the friction member 6. Since the force Fa is larger than the torsional restoring force Fs, the resultant force Fr becomes a force radially outward, and the arcuate surface 60 of the friction member 6 is pressed against the inner peripheral surface of the outer tubular portion 21 by the resultant force Fr. . Therefore, a large frictional force can be generated between the circular arc surface 60 of the friction member 6 and the outer cylindrical portion 21 of the susceptor 2, so that a large damping force can be generated such that the swing of the rotary member 3 is sufficiently attenuated. .

On the contrary, when the tension of the drive belt 101 is reduced, the rotary member 3 is rotated in the direction of the arrow B (the same direction as the X direction) shown in FIG. 5(b) by the torsional restoring force Fs of the coil spring 5. The pulley 4 is swung in such a manner that the belt tension is restored. The friction member 6 receives the torsional restoring force Fs from the coil spring 5 and rotates in the direction of the arrow B, and the arcuate surface 60 of the friction member 6 slides with the inner circumferential surface of the cylindrical portion 21 outside the base 2. The friction member 6 is energized radially inward by the component force Fs2 in the diameter-reduction direction of the torsional restoring force Fs, and therefore, the inner circumference of the cylindrical portion 21 outside the circular arc surface 60 of the friction member 6 and the susceptor 2 The friction generated between the faces is small.

In the case where the end portion of the arcuate surface 60 in the X direction side extends to the circumferential direction of the locking surface 61, the friction member 6 is caused by the circumferential force component Fs1 of the torsional restoring force Fs of the coil spring 5 The circular arc surface 60 is pressed against the inner circumferential surface of the outer tubular portion 21, but in the present embodiment, the circular arc surface 60 of the friction member 6 is located closer to the X direction than the locking surface 61 of the friction member 6 in the circumferential direction. On the opposite side, the arcuate surface 60 of the friction member 6 is not pressed against the inner circumferential surface of the outer tubular portion 21 by the component force Fs1 in the circumferential direction of the torsional restoring force Fs of the coil spring 5, thereby preventing friction. The frictional force between the arcuate surface 60 of the member 6 and the inner peripheral surface of the outer tubular portion 21 is increased.

Therefore, since a frictional force is generated between the arcuate surface 60 of the friction member 6 and the inner circumferential surface of the tubular portion 21 outside the susceptor 2, the frictional member 3 is slightly rotated in the direction of the arrow A, and therefore, the rotation is performed. The member 3 can be sufficiently subjected to the torsional restoring force of the coil spring 5, so that the swing of the rotary member 3 sufficiently follows the reduction of the belt tension.

Further, since the arcuate surface 60 of the friction member 6 is located on the side opposite to the X direction from the locking surface 61, and the friction member 6 is divided by the torsion restoring force Fs of the coil spring 5 Fs2 is energized to the radially inner side, so that the friction member 6 can be prevented from moving in the circumferential direction due to the circumferential force component Fs1 of the torsional restoring force Fs of the coil spring 5, so that the locking surface 61 is self-rotating member 3 The locking surface 31a is disengaged.

Further, since the automatic tension device 1 of the present embodiment can realize the asymmetric damping characteristic only by the friction member 6 and the coil spring 5, it is lightweight and the number of parts is small, so that assembly is easy. Further, since the front end portion of the coil spring 5 is locked to the friction member 6 sandwiched between the cylindrical portion 21 and the rotary member 3 in the radial direction, it is not necessary to be outside the coil spring 5 and the base 2 A large space is secured between the tubular portions 21, and the automatic tensioner can be miniaturized.

Further, in the present embodiment, the arcuate surface 60 of the friction member 6 is formed on the side opposite to the X direction from the locking surface 61. Therefore, the retaining groove 64 is also formed in the X direction with respect to the locking surface 61. On the opposite side, the friction member 6 can be miniaturized in the circumferential direction as compared with the case where the locking surface 61 is formed in the circumferential direction of the holding groove 64.

Moreover, in the present embodiment, the locking surface 61 of the friction member 6 is inclined with respect to the radial direction so as to face the X direction side toward the radially outer side. Therefore, the friction member 6 can be easily assembled.

Next, an automatic tensor 1 according to a second embodiment of the present invention will be described with reference to Fig. 6 . The same components as those in the first embodiment are denoted by the same reference numerals, and their description is omitted. In the first embodiment described above, the rotary member 3 and the shaft 8 are different members, and the shaft 8 is fixed to the rotary member 3. However, in the second embodiment, the shaft 208 and the rotary member 203 are integrated. A protruding portion 231 is formed in the base portion of the shaft 208. The protruding portion 231 has a locking surface 31a and a contact surface 31b formed in the same manner as in the first embodiment.

Next, an automatic tension device 1 according to a third embodiment of the present invention will be described with reference to Figs. 7 and 8 . In the first embodiment described above, the friction member 6 is composed of one piece. However, in the third embodiment, the friction member 306 is composed of two parts.

In the third embodiment, the friction member 306 includes the first member 306x and the second member 306y whose surface hardness is higher than that of the first member 306x. The first part 306x is, for example, polyamine (nylon) 6T) and other synthetic resin injection molding. The second part 306y is, for example, a metal product such as an aluminum alloy casting (ADC12). The first part 306x constitutes the circular arc surface 60 and the front surface (that is, the surface of the friction member 306 that is in contact with the rotary member 3 in the axial direction in the friction member 306). The second component 306y constitutes a locking surface (first locking portion) 61 and a holding groove (second locking portion) 64.

In this manner, since the locking surface (first locking portion) 61 and the holding groove (second locking portion) 64 are formed of the second member 306y having a relatively high surface hardness, even if it acts on the locking surface 61 and remains When the force of the groove 64 increases as the belt tension increases, damage (deformation or depression) of the locking surface 61 and the holding groove 64 can be prevented. Further, since the damage of the locking surface 61 and the holding groove 64 can be prevented, it is possible to cope with a high-load driving system that requires a large belt tension and to reduce the size of the friction member 306. Further, the first member 306x constitutes the circular arc surface 60 and the front surface, and prevents the axial direction from falling off.

Further, in the third embodiment, the first member 306x and the second member 306y are configured to have irregularities on the surfaces facing each other and to mesh with each other in the circumferential direction. Thereby, the first member 306x and the second member 306y can be disposed so as not to be movable in the circumferential direction and can be easily assembled without using the adhesive or the fixing of the rivet.

Further, the irregularities formed in the first member 306x and the second member 306y can be arbitrarily changed in size, shape, pitch, and the like, and a relatively small size, a sharp shape, or a modified example as shown in FIG. 9 can be employed. Narrower distances and so on.

Next, an automatic tension device 1 according to a fourth embodiment of the present invention will be described with reference to Fig. 10 . In the first embodiment, the front end portion (one end) of the coil spring 5 is bent in the vicinity of the front end, and the portion on the front end side of the curved portion extends linearly. However, in the fourth embodiment, the front end portion of the coil spring 405 ( One end is an arc shape, and the arc-shaped portion is held by the holding groove (second locking portion) 464 of the friction member 6.

According to the fourth embodiment, since one end of the coil spring 405 does not have a linear portion, the length of the coil spring 405 can be shortened accordingly, so that the holding groove (second locking portion) 464 can be reduced. The size is such that the friction member 6 can be miniaturized in the circumferential direction (for example, the portion S shown by hatching in Fig. 10 can be omitted). Further, the length of the coil spring 405 is shortened and the circumferential direction of the friction member 6 is reduced, so that the weight of the automatic tension device 1 can be further reduced. Further, since it is not necessary to process one end of the coil spring 405 or the like, simplification of the manufacturing steps and reduction in manufacturing cost can be achieved.

Next, an automatic tension device 1 according to a fifth embodiment of the present invention will be described with reference to Fig. 11 . In the first embodiment, the front end portion (one end) of the coil spring 5 is bent in the vicinity of the front end, and the portion on the front end side of the curved portion extends linearly. However, in the fifth embodiment, the front end portion of the coil spring 505 is One end) includes an arc-shaped portion 505a and a linear portion 505b. Both the arcuate portion 505a and the linear portion 505b are held by the holding groove (second locking portion) 564 of the friction member 6.

According to the fifth embodiment, the size of the holding groove (second locking portion) 564 is larger than when only one end of the coil spring 505 includes an arc-shaped portion or a portion including only a linear portion. Therefore, the friction member 6 is larger than the first embodiment by an amount corresponding to the portion T indicated by the hatching in FIG. 11, so that the area of the arcuate surface 60 can be ensured to be large, and the wear of the circular arc surface 60 can be suppressed.

Next, an automatic tensor 1 according to a sixth embodiment of the present invention will be described with reference to Fig. 12 . In the first embodiment, the locking surface (first locking portion) 61 of the friction member 6 is inclined with respect to the radial direction so as to face the X direction side as it goes radially outward. However, in the sixth embodiment, The locking surface (first locking portion) 661 of the friction member 606 is inclined with respect to the radial direction so as to face the side opposite to the X direction as it goes radially outward. In addition, the locking surface 631a of the protruding portion 631 of the rotary member 3 is inclined with respect to the radial direction so as to face the side opposite to the X direction as it goes radially outward.

According to the sixth embodiment, it is possible to more reliably prevent the friction member 606 from coming out in the circumferential direction when the belt tension is reduced.

The preferred embodiments of the present invention have been described above, but the present invention is not The present invention is limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

In each of the above embodiments, the shaft 8 is fixed to the rotary member 3 and is rotatably attached to the base 2, but the shaft 8 may be fixed to the base 2 and rotatably attached to the rotary member 3. However, in this case, the protruding portion 31 of the rotary member 3 is formed into a ring shape or the like so that the friction members 6, 306, 606 do not come into contact with the shaft 8.

The inclination angles of the engagement faces (first locking portions) 61 and 661 of the friction members 6 and 606 with respect to the radial direction are not limited to those shown in FIGS. 4 and 12 . For example, the locking faces (first locking portions) 61 and 661 may be formed in the radial direction. Also in this modification, as in the sixth embodiment, it is possible to more reliably prevent the friction member 6 from coming out in the circumferential direction when the belt tension is reduced.

Similarly to the posture support portion 24, the posture support portion 25 may have a support surface for supporting the coil spring 5 in the radial direction.

In the first embodiment described above, the posture supporting unit 24 and the posture supporting unit 25 constitute the posture supporting device of the present invention, but the configuration of the posture supporting device of the present invention is not limited thereto. For example, the posture supporting unit 25 may be configured without using the posture supporting unit 25, and only the posture supporting unit 24 may be configured. Further, the posture supporting device may be configured by three or more posture supporting portions formed in the same manner as the posture supporting portion 24 or 25.

In the third embodiment, the first member 306x and the second member 306y are configured to mesh with each other in the circumferential direction, and are not assembled by the adhesive or by fixing with a rivet, but are not limited thereto. . For example, the first part and the second part may be assembled by using an adhesive or by fixing the rivet or the like. Further, after the second component is placed as an insert material in the mold, the synthetic resin that is the first component is injection-molded, and the first component and the second component are integrated.

Each of the above embodiments can be arbitrarily combined. For example, the friction member 306 of the third embodiment may be combined with the coil spring 405 of the fourth embodiment or the coil spring 505 of the fifth embodiment. Further, for example, the friction member 606 of the sixth embodiment may be combined with the coil spring 405 of the fourth embodiment or the coil spring 505 of the fifth embodiment.

Japanese Patent Application No. 2014-028133 filed on Feb. 18, 2014, Japanese Patent Application No. 2014-262127 filed on Dec. 25, 2014, and Japanese Patent Application filed on Jan. 22, 2015 Completed 2015-010210, the contents of which are incorporated herein by reference.

Claims (9)

An automatic tensioner comprising: a base having a cylindrical portion; a rotating member rotatably supported relative to the base; a pulley rotatably disposed on the rotating member; a friction member, The cylindrical portion is sandwiched between the inner circumferential surface of the cylindrical portion and the rotating member in the radial direction; and the coil spring has one end locked to the friction member and the other end of which is locked to the base. The friction member is placed in a state of being compressed in the axial direction of the cylindrical portion, and the friction member is pressed against the rotation member in the axial direction, and the rotation member is rotated in the direction of the base via the friction member. The friction member includes: a circular arc surface that is slidably contacted along an inner circumferential surface of the cylindrical portion; and a first locking portion that is located on the circular arc surface in a circumferential direction of the cylindrical portion Further, the one side direction is locked to the rotation member; and the second locking portion is locked to the outer side in the radial direction of the first locking portion, and is locked to the one end of the coil spring. The automatic tension device according to claim 1, wherein the second locking portion of the friction member is located on the side opposite to the one direction from the first locking portion in the circumferential direction. The automatic tension device according to claim 1, wherein the friction member includes a first component and a second component having a surface hardness higher than that of the first component, wherein the first component constitutes the circular arc surface and is continuous with the circular arc surface a surface of the friction member that is in contact with the rotating member in the axial direction, The second component constitutes the first locking portion and the second locking portion. The automatic tension device of claim 3, wherein the first part and the second part are configured to mesh with each other in the circumferential direction. The automatic tensioner of any one of claims 1 to 4, wherein the one end of the coil spring is arcuate. The automatic tensioner of any one of claims 1 to 4, wherein the one end of the coil spring comprises an arcuate portion and a linear portion. The automatic tensioner according to any one of claims 1 to 4, wherein the base has a pedestal portion disposed at an inner side of one end of the cylindrical portion, the pedestal portion including: an end holding device that holds the coil spring And the other end portion; and the posture supporting device, in the axial direction and the radial direction, supporting a portion of the first loop region of the other end portion side of the coil spring that is held by the end holding device On the side of the one end side. The automatic tension device according to any one of claims 1 to 4, wherein the first locking portion is inclined with respect to the radial direction so as to go to the one direction side toward the outer side in the radial direction. The automatic tension device according to any one of claims 1 to 4, wherein the first locking portion is inclined with respect to the radial direction so as to go to the side opposite to the one direction toward the outer side in the radial direction.