JPH0552413U - Belt tension adjustment device - Google Patents

Abstract

(57) [Summary] [Object] The present invention enables a pulley arm, which is biased by a coil spring, to be assembled with a stopper pin that regulates the amount of rotation in a short time. [Structure] The pulley arm 1 is rotatably attached to a fulcrum shaft 8 provided upright on a fixing member 6, and both ends of a coil spring 29 are
The fixing member 6 and the pulley arm 1 are engaged. The stopper pin 15 press-fitted into the pulley arm 1 is fitted into the circumferential groove 13 provided in the fixing member 6, and the peripheral surface 17 of the stopper pin 15 on the front end side is fitted to the peripheral surface 16 on the rear end side to be press-fitted. Smaller in diameter.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a belt tension adjusting device used for adjusting the tension of a belt for driving an accessory of an engine.

[0002]

[Prior Art]

 As a belt tension adjusting device of this type, a device shown in FIG. 2 is conventionally known. In this device, a fulcrum shaft 8 is erected on a fixing member 6 attached to an engine block or the like, and one end of a pulley arm 1 is rotatably attached to the fulcrum shaft 8 so that the fulcrum shaft 8 and the spring axis line are aligned with each other. One end of the coil spring 29 is connected to the pulley arm 1 and the other end is connected to the fixing member 6. In the above structure, a constant belt tension is applied to the pulley arm 1 by the spring force generated by the twist of the coil spring 29.

[0003]

[Problems to be solved by the device]

 In the structure in which the belt tension is applied to the pulley arm by the twisting of the coil spring as described above, it is necessary to regulate the amount of rotation of the pulley arm within a certain range, and normally, as shown in FIG. Is provided, the stopper pin 15 engaged with the pulley arm 1 is fitted into the groove 13, and the rotation amount is regulated by the contact between the stopper pin 15 and the end wall of the groove 13.

However, as shown in FIG. 6A, the conventional stopper pin has a press-fitting pin 40 in which the entire peripheral surface is formed to have the same diameter, and the entire length of the pin is press-fitted and mounted. As shown in (b), a screw thread is formed on the entire shaft, and a full-thread type screw 41 that screws the entire shaft to install is used. There was a problem of being bad.

Therefore, an object of the present invention is to provide a belt tension adjusting device capable of efficiently attaching the stopper pin in a short time.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention has a structure in which a part of the peripheral surface of the stopper pin is retracted inward from the engagement surface with the pulley arm.

[0007]

[Action]

 With the stopper pin having the above structure, the engagement length can be reduced by the length of the retracted peripheral surface, and the time required for press fitting or screwing can be omitted.

[0008]

【Example】

 1 to 3 show a belt tension adjusting device according to an embodiment. As shown in FIG. 1, the pulley arm 1 has a tension pulley 3 rotatably attached to one end thereof via a bearing 2 and a hole 4 on the inner side at the other end serving as a fulcrum of rotation. A guide wall 5 is provided.

The fixing member 6 is composed of a base 7 and a hollow fulcrum shaft 8 which is erected at the center thereof, and a tightening bolt 9 is inserted inside the fulcrum shaft 8. As shown in FIG. 1, this fixing member 6 is obtained by fitting the hole 4 of the pulley arm 1 on the outer periphery of the fulcrum shaft 8 and screwing the tightening bolt 9 into which the fulcrum shaft 8 is inserted into the engine block or the like. It is installed. A positioning pin 10 is attached to the bearing surface of the fixing member 6, and the fixing member 6 is positioned at a predetermined position between the pin 10 and the tightening bolt 9.

The base 7 of the fixing member 6 is provided with a hole 11 through which a tightening bolt 9 is inserted in the central portion, and an annular wall 12 surrounding a tension adjusting coil spring 29, which will be described later, is formed on the outer peripheral edge. ..

Further, as shown in FIGS. 1 and 2, a regulation groove 13 having a predetermined length in the circumferential direction is provided on the upper portion of the annular wall 12, and is opposed to the regulation groove 13. A stopper pin 15 that fits into the restriction groove 13 is attached to the pin hole 14 of the provided pre-arm 1.

As shown in FIG. 3, the stopper pin 15 has a peripheral surface 16 on one end side formed with a diameter that is press-fitted into the pin hole 14, and a peripheral surface 17 on the other end side is the peripheral surface 16. It is formed with a smaller diameter size, and is inserted into the pin hole 14 from the peripheral surface 17 on the smaller diameter side, and the other peripheral surface 16 is press-fitted into the pin hole 14 for mounting. In this structure, the peripheral surface 17 of the stopper pin 15 protruding from the pin hole 14 contacts the end walls 18 and 19 on both sides of the restriction groove 13 to restrict the rotation amount of the pulley arm 1.

The base of the fulcrum shaft 8 is a spline 20 composed of a large number of axial grooves, and a damper bolt 21 is fitted into the spline 20. The inner diameter surface of the damper bolt 21 is formed in a groove shape corresponding to the spline 20, and the damper bolt 21 is moved in the axial direction of the fulcrum shaft 8 by the guide of the spline 20, but its rotation is stopped.

On the outer peripheral surface of the damper bolt 21, multiple threads 22 with a large helix angle are formed, and the threads 22 are screwed into the threads 23 of the hole 4 of the pulley arm 1.

A collar member 24 is press-fitted at the upper end of the fulcrum shaft 8, and an elastic member 25 made of a coil spring is incorporated between the collar member 24 and the damper bolt 21. The elastic member 25 is assembled in a compressed state, and its spring force applies a pressing force to the damper bolt 21 in the axial direction (downward direction in FIG. 1).

On the other hand, upper and lower ends of the fulcrum shaft 8, that is, between the collar member 24 and the peripheral surface of the hole 4 and between the base end 8a of the fulcrum shaft 8 and the peripheral surface of the hole 4, respectively. Bearing members 26 and 27, which constitute a radial bearing, are incorporated. Further, a bearing member 28 constituting a thrust bearing is incorporated between the lower end of the guide wall 5 of the pulley arm 1 and the upper surface of the base 7.

On the outside of the guide wall 5 of the pulley arm 1, a torsion coil spring 29 for tension adjustment in which a fulcrum shaft 8 and a spring axis are aligned is fitted, and one end of the coil spring 29 is attached to the pulley arm 1 and the other end. Are engaged with the base 7 of the fixing member 6. The surface of the coil spring 29 is subjected to anticorrosion treatment such as dacro treatment.

In the belt tension adjusting device of the embodiment having the above structure, as shown in FIG. 1, after the pulley arm 1 is mounted on the fixing member 6, the stopper pin 15 is press-fitted into the pin hole 14 of the pulley arm 1 and the pin thereof is pressed. The tip of 15 is fitted in the regulation groove 13 to assemble. Next, when the fixing member 6 is fixed to an engine block or the like and the tension pulley 3 is pressed against the belt to rotate the pulley arm 1 by a certain angle, the coil spring 29 is compressed and twisted, and the coil spring 29 tries to be restored. The spring force exerts a constant tension on the belt.

In this state, the stopper pin 15 is located substantially in the center of the regulation groove 13 as shown in FIG. 2, and a gap that allows the rotation of the pulley arm 1 is provided between the pin 15 and both end walls 18 and 19. Is provided.

When the tension of the belt increases from the above-mentioned balanced state and the pulley arm 1 rotates, the damper bolt 21 moves upward, and the elastic member 25 is compressed and contracted. Therefore, the pressing force of the elastic member 25 increases and a large frictional resistance is generated between the damper bolt 21 and the threaded surface of the hole 4, and a large resistance force acts on the rotation of the pulley arm 1.

Conversely, when the belt tension decreases from the above-mentioned balanced state and the pulley arm 1 rotates in the opposite direction to the above, the damper bolt 21 moves downward and the elastic member 25 is stretched. Therefore, the pressing force applied from the elastic member 25 to the damper bolt 21 acts in a direction that assists the rotation of the pulley arm 1, and the pulley arm 1 can rotate with a small resistance.

In the above operation, when the pulley arm 1 tries to rotate beyond the allowable amount, the stopper pin 15 comes into contact with the end walls 18 and 19 of the restriction wall 13 to stop the movement of the pulley arm. Therefore, the tension of the belt is prevented from being excessively tensioned or loosened.

The stopper pin is not limited to the type of the press-fit pin shown in FIG. 3, but as shown in FIGS. 4 and 5, the thread is formed only on the peripheral surface 32 on the rear end side of the shaft portion. However, it is also possible to use half-screw type screws 30 and 31 in which the peripheral surface 33 on the tip side is formed to have a small diameter. In this case, since the screw-in length can be omitted by the length of the distal end side peripheral surface 33, the time required to assemble the pin can be shortened.

Further, in the example of the stopper pin shown in FIG. 3 to FIG. 4, the pin to be fitted into the restriction groove and the tip of the screw are formed in a cylindrical shape, but they are formed inward from the engagement surface with the pulley arm. It may be formed in any shape such as a polygonal shape as long as it is set back.

[0025]

【effect】

 As described above, in the present invention, a part of the peripheral surface of the stopper pin to be engaged with the pulley arm is retracted inward from the engaging surface to reduce the engagement length of the stopper pin. Assembling time can be shortened, and efficient assembling work can be performed.

[Brief description of drawings]

FIG. 1 is a partially longitudinal front view showing an embodiment.

FIG. 2 is a partially cutaway perspective view of the above.

FIG. 3 is a perspective view showing a stopper pin.

FIG. 4 is a perspective view showing another example of a stopper pin.

FIG. 5 is a perspective view showing another example of the stopper pin.

6A and 6B are perspective views showing a conventional example of a stopper pin.

[Explanation of symbols]

 1 pulley arm 3 pulley 6 fixing member 8 fulcrum shaft 13 regulating groove 14 pin hole 15 stopper pin 29 coil spring 30, 31 screw

Claims (1)

[Scope of utility model registration request] 1. A pulley arm is rotatably attached to a fulcrum shaft erected on a fixed member, and one end of a coil spring arranged with its spring axis aligned with the fulcrum shaft is connected to the pulley arm, and the other end is connected to the fixed member. In a belt tension adjusting device in which a stopper pin that engages with a pulley arm is fitted in a circumferential groove provided in the fixing member, a part of the peripheral surface of the stopper pin is A belt tension adjusting device characterized by being retracted inward.