JP2001263440A - Automatic tensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic tensioner which can prevent the degradation of the adjusting function of the belt tension over a long time. SOLUTION: A net-like body 8 formed of a soft metal different in material and hardness from an oscillation arm 4 and a support shaft 7d is embedded along an outer circumference of the support shaft 7d to support the oscillation arm 4 so that the outer circumferential surface of the net-like body is flush with the outer circumferential surface of the support shaft 7d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto tensioner for applying a predetermined tension to a belt wound around a pulley.

[0002]

2. Description of the Related Art A belt is generally used to transmit power from an engine to equipment such as a compressor for an air conditioner mounted on an automobile.
An auto-tensioner is used to keep the belt tension constant and absorb the belt vibration. FIG. 4 is a cross-sectional view showing an example of a conventional auto tensioner. In the figure, a pulley 102 around which a belt 101 is wound is a swinging tip 103 of a swing arm 103.
It is rotatably held with a as a support shaft. A flange 103b and a tubular portion 103c are formed integrally with the swing distal end 103a at the swing base end of the swing arm 103. On the other hand, the support member 104 is an aluminum die-cast product having a spring receiving portion 104a and a support shaft 104b, and is fixed to the engine side.

A cylindrical bush 10 made of a synthetic resin such as nylon is provided on a support shaft 104b of the support member 104.
5 is fitted, and the cylindrical portion 103 of the swing arm 103 is
c is rotatably fitted to the support shaft 104b via the bush 105. A torsion spring 106 is loaded in a compressed state between the spring receiving portion 104a of the support member 104 and the flange portion 103b of the swing arm 103. The torsion spring 106 moves the swing arm 103 in a predetermined direction ( In order to urge the belt 101 in the direction in which the belt 101 is stretched), it is locked in a state of being charged in the winding direction against torsional resistance. Further, a disc-shaped friction member mounting plate 108 is fixed to a distal end of the support shaft 104b of the support member 104 by a fixing screw 109 in a state where rotation is prevented. An annular friction member 107 made of synthetic resin is attached to one surface of the friction member attachment plate 108.
7 is pressed against the flange 103b of the swing arm 103. With the above configuration, the swing arm 103 swings (rotates) within 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 member 107. It becomes possible. The swing center axis at this time is on the center axis of the fixing screw 109.

[0004]

In the auto tensioner having the above structure, the bush 105 is made of a synthetic resin such as nylon. And the support rigidity of the swing arm 103 gradually decreases. In particular, the belt 101 wound around the pulley 102
Is located on the right side of the cylindrical portion 103c of the swing arm 103 in the figure, so that, for example, when the load F acts downward from the upper part of the pulley 102 in the figure, A moment occurs in which the swing arm 103 is tilted clockwise about the cylindrical portion 103c. For this reason, an unbalanced load acts on the bush 105, which causes uneven wear on the bush 105,
There has been a problem that the swing arm 103 is greatly inclined with respect to the axis of the support shaft 104b, and it is impossible to apply an appropriate tension to the belt 101. In addition, when the swing arm 103 is tilted in this manner, an eccentric load acts on the friction member 107, thereby causing eccentric wear on the friction member 107 and deteriorating the function of damping the vibration of the belt 101. There was also a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an auto tensioner capable of preventing the function of adjusting the belt tension from being reduced for a long period of time.

[0006]

According to an aspect of the present invention, there is provided an auto-tensioner, comprising: a pulley which comes into contact with a belt; a metal swing arm which rotatably supports the pulley; A support member having a metal support shaft for rotatably supporting the swing base end of the swing arm, a friction member interposed between the swing arm and the support member, and a swing center for the swing arm. An auto-tensioner comprising: a spring that urges in a direction along an axis to press against the support member via the friction member and urges the swing arm in a predetermined swing direction. At least one of the sliding surfaces of the swing base end of the moving arm and the support shaft of the support member is slid with a mesh made of a soft metal having a different material and hardness from the swing base end and the support shaft. It is specially noted that It is an (claim 1). In the auto tensioner configured as described above, at least one of the sliding surfaces of the swing base end of the swing arm and the support shaft of the support member has a structure in which dissimilar metals having different hardnesses are combined. Therefore, its wear resistance can be improved. Further, the swing base end portion and the support shaft,
Since the contact is made directly without the intervention of the bush made of synthetic resin, that is, the contact is made between the metals, the support rigidity of the swing arm can be improved.

Preferably, the metal net is made of copper or a copper alloy (claim 2). In this case, when the rocking base end and the support shaft are made of an aluminum alloy, the sliding surface of the metal mesh is made of an aluminum alloy. The wear property can be effectively improved.

[0008]

1 and 2 are a sectional view and a side view, respectively, of an auto tensioner showing 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 a swinging tip 4 a of a swing arm 4.
And is fixed to the swinging tip 4a by a dishwasher 5 and a bolt 6. Thereby, the pulley 2
Is rotatably held with the swinging tip 4a of the swing arm 4 as a support shaft. At the swing base end of the swing arm 4,
A flange 4b and a cylindrical portion 4c are formed integrally with the swinging tip 4a, and the swinging tip 4a is
And protrudes rightward from the cylindrical portion 4c.

On the other hand, the support member 7 has a cavity 7a therein.
It is a die-cast product made of an aluminum alloy having a spring receiving portion 7b, a screw hole 7c, and a support shaft 7d around the screw hole 7c. A pair of mounting portions 7e (see FIG. 2) protrude from the side surface. ing. The support member 7 is fixed to the fixing portion by screwing a bolt having the mounting portion 7e inserted into a fixing portion such as a chassis or an engine of the vehicle body.

The swing arm 4 is made of an aluminum alloy die-cast product, and its cylindrical portion 4c is
Is inserted into the outer periphery of the support shaft 7d, and is swingable in a state where the support member 7 is allowed to move rightward in the figure. The spring receiving portion 7b of the support member 7
A torsion spring 9 is mounted between the swing arm 4 and the flange 4b. One end 9 a of the torsion spring 9 is locked by the support member 7, and the other end 9 b is locked by the lower part of the swing arm 4. The torsion spring 9 is locked in a state in which the end portion 9b urges the swing arm 4 in the clockwise direction in FIG. 2 in the winding direction against the torsion resistance. Therefore,
The belt 1 is given a constant tension.

Referring to FIG. 3, a tubular mesh body 8 is embedded in the support shaft 7d of the support member 7 along the outer peripheral surface (sliding surface). As a material of the mesh body 8,
A soft metal having a different material and hardness from the supporting member 7 and the swing arm 4 is used.
When the swing arm 4 is made of an aluminum alloy, copper or a copper alloy is used. The mesh member 8 is formed on the support shaft 7d at the same time when the support member 7 is formed by insert molding.
The mesh is filled with an aluminum alloy as a material of the support shaft 7d. In addition, the reticulated body 8
And the outer peripheral surface of the support shaft 7d are flush with each other.

A disk-shaped friction member mounting plate 12 to which a friction member 11 made of synthetic resin is mounted is mounted on the support member 7 so as to prevent rotation, and the screw hole 7 of the support member 7 is provided.
c, and is fixed by a fixing screw 13 screwed to the fixing member c.
As a result, the friction member 11 is compressed with the torsion spring 9 compressed.
And the flange 4b of the swing arm 4 are in pressure contact with each other.

With the above configuration, the swing arm 4 can swing (rotate) within a predetermined range with respect to the support member 7 which is a fixed member. At this time, the swing center axis is fixed screw 13
On the central axis of. When the belt 1 vibrates, the swing arm 4 repeats the swing in the clockwise direction and the counterclockwise direction in FIG. Since the swing of the swing arm 4 involves an operation of rubbing the flange 4b and the friction member 11 pressed against each other, the swing arm 4 is given swing resistance by friction. Therefore, the vibration energy of the belt 1 changes into thermal energy due to friction, and the vibration of the belt 1 is rapidly attenuated.

In the auto-tensioner having the above structure, the mesh member 8 is embedded in the outer periphery of the support shaft 7d of the support member 7.
And the copper or copper alloy as the material of the mesh body 8, and the wear resistance is dramatically improved by the structure combining the different metals having different hardnesses. be able to. The combination of dissimilar metals having different hardnesses improves the wear resistance, especially when the harder metal of the dissimilar metal is transferred to the surface of the softer metal in fine units and the two metals are combined. This is because the formation of the mixed layer reduces the wear rate. Also, with respect to the cylindrical portion 4c of the swing arm 4, the copper or copper alloy forming the mesh body 8 has poor affinity for the aluminum alloy as the material of the swing arm 4, and forms an intermetallic compound. However, since a mixed layer of both metals is formed, wear of the sliding surface is suppressed. For this reason, it is possible to prevent the sliding surface of the support shaft 7d and the cylindrical portion 4c from being worn early due to the repeated swinging of the swing arm 4. In addition, since the contact between the support shaft 7d and the cylindrical portion 4c is a metal-to-metal contact, the swing arm 4 can be more firmly supported than in the case where the contact is made via a bush made of synthetic resin. Further, uneven wear of the sliding surface due to the moment acting on the swing arm 4 with the belt load F can be suppressed. Accordingly, the support rigidity for the swing arm 4 can be stably secured over a long period of time.

The material of the reticulated body 8 is not limited to the copper or the copper alloy, but may be an aluminum alloy such as tin (Sn), which is a metal having low affinity for the aluminum alloy and softer than aluminum. Various soft metals can be used as long as they form an intermetallic compound between them. The mesh member 8 is provided with a support shaft 7d of the support member 7.
In place of this, it may be embedded along the inner peripheral surface of the cylindrical portion 4c of the swing arm 4, or may be embedded in both the support shaft 7d and the cylindrical portion 4c.

[0016]

As described above, according to the auto tensioner according to the first aspect, at least one of the sliding surfaces of the swing base end of the swing arm and the support shaft of the support member is formed by:
Since it is a structure combining different metals with different hardness,
Its wear resistance can be improved. Further, since the swing base end and the support shaft are in direct contact with each other without the intervention of the bush made of synthetic resin, the support rigidity of the swing arm can be improved. Therefore, the function of adjusting the belt tension can be favorably maintained over a long period of time.

According to the second aspect of the present invention, since the mesh member is made of copper or a copper alloy, when the swing base end of the swing arm and the support shaft of the support member are made of an aluminum alloy, the mesh member is made of aluminum alloy. The wear resistance of the sliding surface can be more effectively improved, and the function of adjusting the belt tension can be favorably maintained for a longer period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of an auto tensioner showing one embodiment of the present invention.

FIG. 2 is a side view of the auto tensioner.

FIG. 3 is a cross-sectional view showing details of a mesh body.

FIG. 4 is a sectional view showing an example of a conventional auto tensioner.

[Explanation of symbols]

 2 Pulley 4 Swing arm 4a Swing tip 4b Flange 4c Cylindrical part 7 Support member 7d Support shaft 8 Net-like body 9 Torsion spring 11 Friction member

Claims (2)

[Claims] 1. A pulley that comes into contact with a belt, a metal swing arm that rotatably supports the pulley, and a metal support shaft that rotatably supports a swing base end of the swing arm. And a friction member interposed between the swing arm and the support member, and biasing the swing arm in a direction along a swing center axis, via the friction member, An auto-tensioner having a spring that presses against the support member and urges the swing arm in a predetermined swing direction, wherein a sliding base end of the swing arm and a support shaft of the support member are respectively slid. An auto-tensioner, wherein a net-like body made of a soft metal having a different material and hardness from the rocking base end and the support shaft is embedded in at least one of the moving surfaces so as to be flush with the sliding surface. 2. The auto-tensioner according to claim 1, wherein the metal net is made of copper or a copper alloy.