JP2004270824A - Auto-tensioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auto-tensioner which can continuously use a friction plate even when the friction plate is broken, and prolong the lifetime thereof. <P>SOLUTION: An outer circumferential constraining part 4d which surrounds the outer circumference of a friction plate 10 and substantially maintains the original shape when a friction plate 10 is broken is provided along an outer circumferential edge of a flange part 4b of an oscillation member 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an auto-tensioner that applies a predetermined tension to a belt wound around a pulley.
[0002]
[Prior art]
For example, a belt is generally used to transmit power from an engine to auxiliary equipment such as an air conditioner compressor mounted on an automobile. The tension of this belt is kept constant by the auto tensioner. The auto tensioner has a pulley around which the belt is wound at the tip of a swing member that can swing about a fixed portion, and applies tension to the belt by the force of a torsion coil spring. The rocking member is provided with rocking resistance by a friction plate provided on the rocking base, and the rocking energy of the rocking member is attenuated by the rocking resistance.
With such an auto tensioner, it is possible to absorb an attachment error of an accessory, a dimensional change due to a temperature change, a variation in a belt length, and the like. Further, belt tension fluctuations due to engine rotation fluctuations and the like can be absorbed, belt vibration and abnormal noise can be prevented, and the original life of the belt can be ensured.
[0003]
FIG. 5 is a sectional view of a main part showing an example of a conventional auto tensioner. In the figure, a pulley 102 around which a belt 101 is wound is rotatably attached to a swinging tip 103a of a swinging member 103. On the swing base of the swing member 103, a flange 103b and a tubular portion 103c are formed integrally with the swing tip 103a. The cylindrical portion 103c is rotatably fitted to a shaft portion 104b of the support member 104 via a bush 105 made of synthetic resin. The swing member 103 and the support member 104 are made of an aluminum die-cast product.
[0004]
A torsion coil spring 106 is loaded in a compressed state between a spring receiving portion 104a of the support member 104 and a flange portion 103b of the swing member 103. The torsion coil spring 106 holds the swing member 103 at a predetermined position. (The direction in which the belt 101 is stretched).
Further, a disc-shaped pressing plate 108 is fixed to a tip of the shaft portion 104b of the support member 104 by a fixing screw 109 in a state where rotation is stopped. An annular friction plate 107 is pressed against one surface of the holding plate 108. The friction plate 107 is made of a synthetic resin and has a thickness of about 3 mm, and its non-sliding surface 107 a is in contact with the flange 103 b of the swing member 103. A large number of small projections are formed on the flange portion 103b, and the small projections cut into the non-sliding contact surface 107a of the friction plate 107 to restrict the rotation of the friction plate 107. Also, a plurality of concave grooves 107c are usually provided radially on the sliding contact surface 107b of the friction plate 107, and wear powder generated from the sliding contact surface 107b due to wear is generated by the swing of the swing member 103. To collect in these concave grooves 107c.
With the above configuration, the swing member 103 swings (rotates) in a predetermined range via the bush 105 with respect to the support member 104 on the fixed side in a state where the swing resistance is given by the friction plate 107. It becomes possible.
[0005]
[Patent Document 1]
JP-A-11-94036 (page 4 and FIG. 2)
[0006]
[Problems to be solved by the invention]
In the conventional auto tensioner described above, since the concave groove 107c is formed in the friction plate 107 or the small projection is cut into the friction plate 107, the minimum thickness of the friction plate 107 is reduced. For this reason, the friction plate 107 may be broken and divided into a plurality of parts starting from the minimum thickness portion with the use thereof. Here, since the friction plate 107 is freely movable in the radial direction, if the friction plate 107 is divided into a plurality of pieces as described above, the separation pieces 107d are dispersed in the circumferential direction and the radial direction (see FIG. 6), and the rocking motion is caused. The swing resistance cannot be sufficiently imparted to the moving member 103, and continuous use becomes difficult.
[0007]
In view of the above-described conventional problems, an object of the present invention is to provide an auto-tensioner capable of continuously using a friction plate even if the friction plate is broken and extending its life. And
[0008]
[Means for Solving the Problems]
An auto-tensioner according to the present invention includes a swing member rotatably supporting a pulley around which a belt is wound, a support member swingably supporting the swing member, and the swing member with respect to the support member. A spring for urging in a predetermined swing direction, a swing base disposed between the swing base of the swing member and the support member, and arranged around a swing center axis of the swing member; An automatic friction device comprising: an annular friction plate for imparting swing resistance to the swing member; and a friction plate pressing member provided on one of the swing base portion and the support member of the swing member for slidingly contacting the friction plate. In the tensioner, one of the rocking base of the rocking member and the friction plate pressing member is provided with an outer circumferential restraining portion that surrounds the outer periphery of the friction plate and substantially maintains its original shape when the friction plate is broken. It is characterized by:
[0009]
According to the auto-tensioner having the above-described configuration, even when the friction plate is broken, the original shape of the friction plate can be substantially maintained by the outer peripheral restraining portion. Can be granted. Therefore, the broken friction plate can be continuously used, and its life can be extended.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 are a cross-sectional view and a side view, respectively, of an auto-tensioner according to an embodiment of the present invention. In FIG. 1, a pulley 2 around which a belt 1 is wound has a ball bearing 3 mounted at the center thereof. The inner ring of the ball bearing 3 is externally fitted to the tip 4 a of the swing member 4 and is fixed to the tip 4 a by bolts 5 and nuts 6. In this manner, the pulley 2 is rotatably supported by the tip 4a of the swing member 4. The swing base of the swing member 4 is integrally formed with a flange 4b, an inner cylindrical portion 4c, and an outer cylindrical portion 4e integrally with the tip portion 4a. The swing member 4 is an aluminum die-cast product.
[0011]
On the other hand, the supporting member 7 for supporting the swing member 4 is formed by aluminum die casting including a shaft portion 7a having a hollow inside, a spring receiving portion 7b formed around the shaft portion 7a, and a mounting portion 7c. Goods. The support member 7 is fixed by fixing the mounting portion 7c to a fixing portion such as a chassis of a vehicle body or an engine. The outer peripheral surface of the shaft portion 7a has a tapered shape slightly tapered rightward in FIG. 1 due to the draft of the mold. A substantially cylindrical bush 8 made of nylon or the like is mounted on the outer peripheral surface of the shaft portion 7a.
[0012]
The swing member 4 is swingable with respect to the support member 7 by fitting the inner peripheral cylindrical portion 4 c to the outer periphery of the bush 8. A torsion coil spring 9 is mounted between the spring receiving portion 7b of the support member 7 and the flange 4b of the swing member 4. One end 9 a of the torsion coil spring 9 is locked by the support member 7, and the other end 9 b is locked by the swing member 4.
With the above configuration, the swing member 4 can swing (rotate) within a predetermined range with respect to the support member 7 via the bush 8. At this time, the swing center axis X coincides with the center axis of the shaft portion 7a. The torsion coil spring 9 urges the swing member 4 in the clockwise direction in FIG. 2 in a state where the belt 1 is wound, and applies a constant tension to the belt 1.
[0013]
On the other hand, the annular friction plate 10 is disposed around the swing center axis X, and is interposed between the flange 4 b of the swing member 4 and the holding plate 11 in a state perpendicular to the swing center axis X. are doing. The friction plate 10 is made of, for example, a clutch facing material having a thickness of about 3 mm, and a V-shaped groove 10b for storing abrasion powder of the friction plate 10 is radially formed on the sliding contact surface 10a side.
The non-sliding surface 10c of the friction plate 10 is provided with a small protrusion projecting from the flange 4b of the swinging member 4 so that the small protrusion projects in the circumferential direction between the friction plate 10 and the flange 4b. Relative movement is regulated.
[0014]
The outer periphery of the friction plate 10 is surrounded by an outer periphery restricting portion 4d provided along an intersection between the flange portion 4b of the swing member 4 and the outer cylindrical portion 4e. The outer peripheral restraining portion 4d is an annular member provided with a slight gap with respect to the friction plate 10 (see FIG. 3), protrudes from the flange portion 4b toward the holding plate 11, and has a protruding height. The height is about の of the thickness of the friction plate 10.
[0015]
The inner peripheral shape of the holding plate 11 and the outer peripheral shape on the right end side (FIG. 1) of the support member 7 form a chrysanthemum-shaped detent structure that fits together. Further, the holding plate 11 is fixed by a retaining means (not shown) attached to the screw hole 7 d of the support member 7 in a state of being fitted to the support member 7.
The pressing plate 11 is a disk-shaped metal plate processed, and has a chrysanthemum-shaped inner peripheral shape and a circular outer peripheral shape as described above. Reinforcing grooves 11b are formed at predetermined intervals along the circumferential direction on the side of the pressing plate 11 that is in sliding contact with the friction plate 10. Wear powder of the friction plate 10 can be stored in the concave groove 11b.
The torsion coil spring 9 urges the swing member 4 against the support member 7 by an elastic force in the swing center axis X direction, whereby the flange portion 4b and the holding plate 11 separate the friction plate 10 from each other. It is urged so as to push each other in a direction parallel to the swing center axis X.
[0016]
When the swinging member 4 swings counterclockwise or clockwise in FIG. 2 when the tension of the belt 1 fluctuates, the auto-tensioner having the above-described configuration causes the swing base 4b in FIG. It rotates around the swing center axis X. On the other hand, the holding plate 11 is fixed to the support member 7. Therefore, the relative rotation between the holding plate 11 and the flange 4b causes friction between the friction plate 10 fixed to the flange 4b and the holding plate 11. Thereby, a swing resistance (friction resistance) is given to the swing member 4.
[0017]
Further, in the auto tensioner, since the outer periphery of the friction plate 10 is surrounded by the outer periphery restraining portion 4d, even when the friction plate 10 is broken during use and divided into a plurality of pieces, each divided piece is radially separated. And the original shape of the friction plate 10 can be substantially maintained. For this reason, a sufficient swing resistance can be continuously provided to the swing member 4, and its continuous use becomes possible.
[0018]
In the above-described embodiment, the outer periphery restricting portion 4d that restricts the outer periphery of the friction plate 10 is provided on the swing member 4 side, but may be provided along the outer peripheral edge of the holding plate 11 ( (See FIG. 4).
[0019]
【The invention's effect】
As described above, according to the auto-tensioner according to the present invention, even when the friction plate is broken, the original shape of the friction plate is substantially maintained by the outer peripheral restraining portion, and the swing resistance to the swing member is sufficiently increased. Therefore, the broken friction plate can be continuously used, and the life of the friction plate can be extended.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a main part of an auto tensioner according to an embodiment of the present invention.
FIG. 2 is a side view of the auto tensioner.
FIG. 3 is a partially cutaway side view of the auto tensioner of FIG. 1;
FIG. 4 is a side view of a main part showing another embodiment.
FIG. 5 is a sectional view showing a main part of a conventional auto tensioner.
FIG. 6 is a main part side view showing a state in which a friction plate is broken in a conventional auto tensioner.
[Explanation of symbols]
Reference Signs List 1 belt 2 pulley 4 swing member 4b flange (swing base)
4d Outer circumference restraint part 7 Support member 9 Torsion coil spring 10 Friction plate 11 Pressing plate (friction plate pressing member)

Claims (1)

A swinging member that rotatably supports a pulley around which the belt is wound,
A support member for swingably supporting the swing member,
A spring for urging the swing member in a predetermined swing direction with respect to the support member;
An annular friction plate disposed between a swing base of the swing member and the support member and arranged around a swing center axis of the swing member, and imparting swing resistance to the swing of the swing member; When,
An auto-tensioner including a friction plate pressing member provided on one of the swing base portion and the support member of the swing member and slidingly contacting the friction plate;
An outer circumferential restraining portion is provided on one of the swing base portion of the swing member and the friction plate pressing member to surround an outer periphery of the friction plate and substantially maintain its original shape when the friction plate is broken. And an auto tensioner.

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