JP2016008666A - Auto tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auto tensioner having a more superior damping characteristic.SOLUTION: An auto tensioner 1 comprises: a fixing member 9; an arm 5 having a shaft part 5a fitted to the fixing member 9 and an end part 5b extending from an upper part of the shaft part 5a in a radial outer direction, and rotatably arranged around an axis of the shaft part 5a with respect to the fixing member 9; a pulley 7; a twisting coil spring 11 for biasing the arm 5 around an axis direction of the shaft part 5b; a damping member 17 sliding on an inner circumferential surface of a portion of the fixing member 9 that encloses the twisting coil spring 11 or an inner circumferential surface of a portion enclosing the twisting coil spring 11 of the arm 5, and having a circular arc-shaped section; and a coil spring 21 installed between one end of the damping member 17 in its circumferential direction and a part of the fixing member or a part of the arm 5.

Description

  The technology disclosed in this specification relates to an auto tensioner used for an automobile or the like.

  2. Description of the Related Art An auto tensioner that holds a predetermined tension on a belt by applying tension to a belt that drives an engine accessory such as an automobile is widely used. The auto tensioner has a function of damping fluctuations in belt tension.

  Patent Document 1 discloses an auto tensioner that includes a torsion spring housed inside the cylindrical member in the axial direction and a friction member disposed along the inner peripheral surface of the cylindrical member. In this auto tensioner, when the arm swings, the side surface of the friction member comes into contact with the inner peripheral surface of the cylindrical member, thereby generating a damping force to attenuate the swing of the pulley.

  Patent Document 2 discloses an auto tensioner provided with a wedge-shaped friction member. In this auto tensioner, when the pulley swings to the belt tension side of the accessory driving belt, the friction member slides along the outer periphery of the support shaft, and when the pulley swings to the belt slack side, the friction member moves to the support shaft. The pulley is pressed against the outer periphery to attenuate the swing of the pulley.

JP 2003-254399 A Japanese Utility Model Publication No. 4-105246

  However, as the engine rotation fluctuation and the load on the auxiliary machine increase in recent years, further improvement in damping characteristics is desired for the auto tensioner. In particular, the damping characteristic is required to have excellent anisotropy that generates a sufficient damping force when the torsion of the arm increases.

  An object of the present invention is to provide an auto tensioner having more excellent damping characteristics.

  An auto tensioner according to an embodiment of the present invention includes a fixing member, a shaft portion fitted to the fixing member, and an end portion extending radially outward from an upper portion of the shaft portion, and An arm provided rotatably with respect to a member in a direction around the shaft of the shaft, a pulley attached to an end of the arm, and at least a part of the shaft. A torsion coil spring that urges the arm in a rotating direction, and an inner peripheral surface of a portion of the fixing member that surrounds the torsion coil spring, or the torsion coil of the arm. It is interposed between a damping member that slides on the inner peripheral surface of the portion surrounding the spring and has an arc-shaped cross section, one end in the circumferential direction of the damping member, and a part of the fixing member or a part of the arm. And a coil spring.

  According to the auto tensioner according to the embodiment of the present invention, it is possible to obtain more excellent damping characteristics.

FIG. 1 is a cross-sectional view showing a configuration of an auto tensioner according to an embodiment of the present invention. FIG. 2 is a top view of the fixing member of the auto tensioner shown in FIG. FIG. 3 is a view of a fixing member in a modification of the auto tensioner shown in FIG. 1 as viewed from above. FIG. 4 is a diagram schematically showing an auto tensioner and a belt driving device according to an embodiment of the present invention.

-Configuration of auto tensioner-
FIG. 1 is a cross-sectional view showing a configuration of an auto tensioner 1 according to an embodiment of the present invention. FIG. 2 is a plan view showing the fixing member 9 of the auto tensioner 1 according to this embodiment. FIG. 2 is a view of the fixing member 9 as viewed from above. In this specification, for the sake of convenience, the description will be made with the fixing member 9 side as the lower side and the pulley 7 side as the upper side with reference to the vertical direction shown in FIG. 1 (that is, the axial direction of the inner cylinder portion 9a and the shaft portion 5a).

  As shown in FIGS. 1 and 2, the auto tensioner 1 of the present embodiment includes a fixing member 9, an arm 5, and a pulley 7.

  The fixing member 9 includes an inner cylinder part 9a and a bracket (outer cylinder part) 9b that surrounds the outer side of the inner cylinder part 9a with a predetermined interval and is connected to the lower part of the inner cylinder part 9a. . A torsion coil spring 11 is installed in a space (holding portion 12) formed by the inner tube portion 9a and the outer tube portion 9b. The inner peripheral surface of the inner cylinder portion 9a is tapered so that the inner diameter decreases from the upper side to the lower side, for example. A bush 13 made of a resin such as nylon is attached to the inner peripheral surface.

  Attachment holes 14a and 14b are formed in a portion extending radially outward (horizontal direction) from the outer cylinder portion 9b. The mounting holes 14a and 14b are used for attaching the fixing member 9 to an engine or the like. The fixing member 9 is made of, for example, a metal such as aluminum, and the whole can be integrally molded by a known method. A thrust washer 20 made of resin or the like is attached under the fixing member 9, and a base plate 19 made of metal or the like is attached under the thrust member 20.

  The arm 5 has a shaft portion 5a having at least a lower portion inserted through the inner cylinder portion 9a, and an end portion 5b extending from the upper portion of the shaft portion 5a in the radially outward direction (horizontal direction).

  The arm 5 is attached to the fixed member 9 so as to be rotatable about the axis of the inner cylinder portion 9a and the shaft portion 5a with the bush 13 interposed. In the auto tensioner 1 of the present embodiment, the counterclockwise direction in FIG. 2 among the rotation directions of the arm 5 is the “twist direction”, and the clockwise direction is the “anti-twist direction”. Yes. The arm 5 is made of metal such as aluminum and can be molded by a known method.

  The pulley 7 is rotatably supported on the end portion 5b of the arm 5 using a bolt 23, and includes a ball bearing, a dust shield, and the like. A belt for driving an auxiliary machine such as a vehicle is wound around the pulley 7. A predetermined tension is applied from the auto tensioner 1 to the belt via the pulley 7.

  One end of the torsion coil spring 11 is locked to the locking portion 5 e of the arm 5, and the other end is locked to the fixing member 9, whereby tension can be applied to the belt through the pulley 7. The axis of the torsion coil spring 11 substantially coincides with the axis of the inner cylinder portion 9a. The torsion coil spring 11 is preferably made of a metal such as silicon chrome copper or a metal compound.

  In the auto tensioner 1 of the present embodiment, a damping assisting member 15 having an arcuate cross section is provided outside the torsion coil spring 11 along the inner peripheral surface of the outer cylinder portion 9b. A damping member 17 having an arcuate cross section is provided between the outer peripheral surface of the damping auxiliary member 15 and the inner peripheral surface of the outer cylinder portion 9b. As for the damping member 17, the damping auxiliary member 15 and the damping member 17 are provided along the inner peripheral surface of the outer cylindrical portion 9b within a range of, for example, 270 ° or more, more preferably 300 ° or more.

  The damping auxiliary member 15 interposed between the torsion coil spring 11 and the damping member 17 is a member provided so that the force applied from the torsion coil spring 11 is uniformly transmitted to the damping member 17. (Aluminum, iron, etc.) or resin (nylon, polyamide, modified polyamide, etc.) may be used. In the auto tensioner 1 of the present embodiment, a bendable damping ring is used as an example of the damping auxiliary member 15.

  The damping member 17 generates a damping force as described later by sliding on the inner peripheral surface of, for example, a cylindrical bracket (outer cylinder portion 9b). Here, in the example shown in FIG. 2, the damping member 17 is locked to a part of the arm 5 and slides on the inner peripheral surface of the outer cylinder portion 9 b.

Alternatively, the arm 5 may be provided with a cylindrical portion surrounding the outside of the torsion coil spring 11, and the damping member 17 may slide on the inner peripheral surface of the cylindrical portion to generate a damping force as described later ( Not shown). In this case, the damping member 17 is locked to the fixing member 9 side.
As the damping member 17, for example, a spring support made of a thermoplastic resin such as nylon, polyethylene, or polyethersulfone (PES) is used.

  As shown in FIG. 1, the damping auxiliary member 15 and the damping member 17 may be provided in a region that can come into contact with the upper portion of the torsion coil spring 11, but can come into contact with a portion other than the upper portion of the torsion coil spring 11. It may be provided in the area.

  In addition, as shown in FIG. 2, a part of the arm 5 may be formed outside the torsion coil spring 11 and inside the outer tube portion 9 b, and in that case, one end of the portion of the arm 5. Is a locking portion (abutting portion; first locking portion) 5d in which the damping assisting member 15 and the damping member 17 are locked, and the end opposite to the locking portion 5d will be described later. It is the latching | locking part (2nd latching | locking part) 5c by which the coil spring 21 was latched.

  Here, of the end portions of the damping member 17 in the direction around the axis, the end portion in the anti-twist direction is referred to as a first end portion, and the end portion in the arm twist direction is referred to as a second end portion. At this time, in the autotensioner 1 of the present embodiment, the damping assisting member 15 is disposed between one end (first end) in the circumferential direction of the damping assisting member 15 and the damping member 17 and the locking portion 5c of the arm 5. And the coil spring 21 which presses the damping member 17 to the circumferential direction is interposed. A circumferential preload (arrow Fp shown in FIG. 2) is applied to the damping assisting member 15 and the damping member 17 by the coil spring 21.

  In this configuration, when the arm 5 moves in the twisting direction, the torsion coil spring 11 moves in a direction shifted from the end by a certain angle (for example, 90 °) with the locking portion 5e of the arm 5 as a fulcrum. Then, the torsion coil spring 11 comes into contact with the damping assisting member 15, and a load Fs is applied from the torsion coil spring 11 to the damping member 17 through the damping assisting member 15. Thereby, the damping member 17 slides frictionally between the outer cylinder part 9b, and a damping force generate | occur | produces.

  On the other hand, by providing the above-mentioned preload Fp, the damping auxiliary member 15 and the damping member 17 spread in the circumferential direction with the locking portion 5d as a fulcrum. For this reason, the closer to the coil spring 21, the larger the load Fr in the radially outward direction, and the smaller the load Fr toward the locking portion 5d. In this state, when the arm 5 moves in the torsional direction, the outer cylinder part 9b moves in a direction in which the load Fr becomes relatively large, so that the frictional force between the damping member 17 and the outer cylinder part 9b Increases, resulting in an increase in damping force.

  Accordingly, since the load Fr generated by the preload Fp is added to the load Fs applied from the torsion coil spring 11, a stronger damping force can be generated as compared with the case where the coil spring 21 is not provided.

  On the other hand, when the arm 5 moves in the anti-twist direction, the torsion coil spring 11 returns to the original position, so that the force (load Fs) by which the torsion coil spring 11 presses the damping member 17 becomes weaker. The frictional force generated between the outer cylinder portion 9b and the outer cylinder portion 9b is reduced. Further, in this case, the outer cylinder portion 9b moves in a direction in which the load Fr becomes relatively small. Therefore, the frictional force between the damping member 17 and the outer cylinder portion 9b becomes small, and as a result, the damping force becomes small. Become.

  As described above, according to the auto tensioner 1 of the present embodiment, the frictional resistance when the arm 5 moves in the twisting direction can be increased, and the frictional resistance when the arm 5 moves in the anti-twisting direction can be increased. It can be made much smaller than before. Thereby, the damping force excellent in one direction can be obtained, and the displacement of the arm 5 can be effectively suppressed. For this reason, it is possible to stably drive the accessory drive belt system even when the engine rotational fluctuation or the load on the accessory increases.

  FIG. 2 shows an example in which the coil spring 21, the damping auxiliary member 15, and the damping member 17 are locked to the arm 5, and frictional sliding occurs between the damping member 17 and the outer cylindrical portion 9 b of the fixing member 9. However, a portion surrounding the outside of the torsion coil spring 11 may be provided on the shaft portion 5a of the arm 5, and the damping member 17 may be configured to slide on the inner peripheral surface of the portion. In this case, the coil spring 21, the damping auxiliary member 15, and the damping member 17 are locked to the fixing member 9, and damping is performed between the inner peripheral surface of the portion surrounding the torsion coil spring 11 in the shaft portion 5 a and the damping member 17. A configuration in which frictional sliding occurs through the auxiliary member 15 may be adopted. At this time, for example, a convex portion protruding with a predetermined width in the radial inward direction is formed in a region where the damping auxiliary member 15 and the damping member 17 are not provided in the inner peripheral surface of the outer cylindrical portion 9b. The damping auxiliary member 15 and the damping member 17 may be locked to one end of the portion, and the coil spring 21 may be locked to the other end of the convex portion.

  Even in the case of adopting this configuration, it is possible to obtain a damping force having excellent unidirectionality as in the case of the auto tensioner 1 shown in FIGS.

  Next, a modified example of the auto tensioner 1 of the present embodiment will be described. FIG. 3 is a plan view showing the fixing member 9 in the auto tensioner according to the modification.

  As shown in the figure, in the auto tensioner according to this modification, the twisting direction of the arm 5 is opposite to that of the auto tensioner 1 shown in FIGS. 1 and 2, and the coil spring 21 is connected to the damping auxiliary member 15 and the damping. The position connected to the member 17 is also opposite to that of the auto tensioner 1. However, the point that the coil spring 21 is connected to the first end portion (the end portion in the anti-arm torsion direction) of the damping auxiliary member 15 and the damping member 17 is common.

  That is, the second end portions (end portions in the arm torsion direction) of the damping auxiliary member 15 and the damping member 17 are locked to the locking portion (applying portion) 5f of the arm 5, and the coil spring 21 is connected to the damping auxiliary member. 15 and a first end of the damping member 17 and a locking portion (second locking portion) 5g of the arm 5.

  Even in such a configuration, when the arm 5 moves in the arm twisting direction, the outer tube portion 9b receives a large load Fr, and when the arm 5 moves in the anti-arm twisting direction, the outer tube Since the portion 9b receives a relatively small load, it is possible to obtain an excellent unidirectional damping force similarly to the auto tensioner 1 shown in FIG.

−Configuration of belt drive device−
FIG. 4 is a diagram schematically showing the auto tensioner and the belt driving device according to the present embodiment.

  The auto tensioner 1 transmits the torque generated by the torsion coil spring 11 (see FIG. 2) to the accessory driving belt 22 via the pulley 7. The belt drive device includes, for example, a drive pulley 4 and pulleys 2a and 2b. The arm 5 of the auto tensioner 1 rotates so that the tension of the belt 22 becomes constant. That is, when the tension of the belt 22 increases, the belt 22 rotates against the torsional torque of the torsion coil spring 11 in the direction opposite to the urging direction (torsion direction of the arm 5). On the other hand, when the tension of the belt 22 decreases, the arm 5 rotates in the biasing direction of the torsion coil spring 11 by the torsion torque of the torsion coil spring 11.

  The auto tensioner 1 of the present embodiment has a unidirectional damping characteristic as described above, and when the tension of the belt 22 increases, the sliding between the damping member 17 and the outer cylindrical portion 9b. Since the resistance increases, the rotation of the arm 5 is effectively damped.

  On the other hand, when the tension of the belt 22 is abruptly decreased due to engine start or the like, the sliding resistance between the damping member 17 and the outer cylinder portion 9b is greatly reduced, so that the arm 5 is returned to the original position. The belt 22 can be returned quickly, and the vibration of the belt 22 can be quickly reduced. This effect can be similarly obtained when the auto tensioner according to the above-described modification is used.

  The configuration of the auto tensioner described above is an example of the embodiment, and the configuration, shape, arrangement, and the like of each member can be appropriately changed without departing from the gist of the present invention.

  As described above, the auto tensioner according to an example of the present invention can be applied to various vehicles and the like.

1 Auto tensioner 2a, 2b, 7 Pulley 4 Drive pulley 5 Arm 5a Shaft 5b End
5c, 5d, 5e, 5f, 5g Locking part 7 Pulley 9 Fixing member 9a Inner cylinder part 9b Outer cylinder part 11 Torsion coil spring 12 Holding part 13 Bushing 14a, 14b Mounting hole 15 Damping auxiliary member 17 Damping member 19 Base plate 20 Thrust Member 21 Coil spring 22 Belt 23 Bolt Fp Preload Fs Load by torsion coil spring Fr Load generated by preload Fp

Claims (7)

A fixing member;
It has a shaft part fitted to the fixing member and an end part extending radially outward from the upper part of the shaft part, and is provided so as to be rotatable about the axis of the shaft part with respect to the fixing member. Arm,
A pulley attached to the end of the arm;
A torsion coil spring that surrounds at least a part of the shaft portion and biases the arm in a direction around the shaft of the shaft portion;
It is arranged outside the torsion coil spring, and slides on an inner peripheral surface of a portion of the fixing member surrounding the torsion coil spring or an inner peripheral surface of a portion of the arm surrounding the torsion coil spring, A damping member having an arcuate cross section;
An auto tensioner comprising a circumferential end of the damping member and a coil spring interposed between a part of the fixing member or a part of the arm. The auto tensioner according to claim 1,
The fixing member includes an inner cylinder part positioned inside the torsion coil spring, and an outer cylinder part that surrounds the outer side of the inner cylinder part with a space therebetween and is connected to the lower part of the inner cylinder part. And
The torsion coil spring is installed in a holding part constituted by the inner cylinder part and the outer cylinder part,
The shaft portion is inserted through the inner cylinder portion,
The damping member is locked to a part of the arm and slides on the inner peripheral surface of the outer cylinder part,
The auto tensioner, wherein the coil spring is interposed between a circumferential end of the damping member and a part of the arm. The auto tensioner according to claim 1,
The shaft portion is provided with a portion surrounding the outside of the torsion coil spring,
The damping member is locked to a part of the fixing member, and slides on an inner peripheral surface of a portion of the arm surrounding the outside of the torsion coil spring,
The auto tensioner, wherein the coil spring is interposed between one end of the damping member in the circumferential direction and a part of the fixing member. In the auto tensioner as described in any one of Claims 1-3,
When the outer circumferential load generated by the coil spring being applied to the damping member by the coil spring, and when the arm moves in the arm twist direction, which is one of the directions around the axis of the shaft portion. An auto tensioner, wherein a load in a radially outward direction is applied from the torsion coil spring. The auto tensioner according to claim 2,
One of the shafts in the direction around the axis is the arm twist direction, and the other is the anti-twist direction, and the end in the anti-twist direction is the first end of the end of the damping member around the axis, and the arm twist When the direction end is the second end,
The coil spring is connected to the first end of the damping member;
The auto tensioner, wherein the second end portion of the damping member is locked to the first locking portion of the arm or the outer cylinder portion. The auto tensioner according to claim 5,
The damping member is bendable;
The auto-tensioner, wherein the damping member extends in the circumferential direction with the first locking portion as a fulcrum. In the auto tensioner according to any one of claims 1 to 6,
A damping assisting member interposed between the torsion coil spring and the damping member and having an arcuate cross section;
One end of the damping auxiliary member in the circumferential direction is connected to the coil spring.

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