JPH0512815U - Belt tension adjustment device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the distance between the center of the tension pulley that applies tension to the belt and the pulley support surface of the fixing member in a belt tension adjusting device that holds the tension of the belt such as a timing belt constant. . [Structure] A support shaft 2 attached to a fixed member rotatably supports an eccentric position of a pulley support 6. The tension pulley 8 is rotatably supported on the outer side of the pulley support 6. A tension adjusting spring 21a for urging the pulley support 6 toward the belt tension side is provided on the side opposite to the fixed member of the pulley support 6 to bring the tension pulley 8 close to the pulley support surface of the fixed member.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a belt tension adjusting device that keeps the tension of a belt such as a timing belt of an automobile engine constant.

[0002]

[Prior Art]

 As a belt tension adjusting device for keeping the tension of the timing belt constant, the one described in Japanese Utility Model Laid-Open No. 3-354 is conventionally known.

In this belt tension adjusting device, an idler is rotatably provided outside a movable eccentric member whose eccentric position is rotatably supported, and a spring force of a torsion coil spring is applied to the movable eccentric member to rotate the idler into a belt. Is pressed against.

[0004]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional belt tension adjusting device, the torsion coil spring for tension adjustment is incorporated between the idler and the fixing member such as the engine block that supports the idler. Since the distance from the support surface to the center of the idler is long, it is difficult to replace it with a fixed tensioner, and it is difficult to assemble the tension adjusting device.

The present invention solves the above-mentioned conventional problems, shortens the distance from the pulley supporting surface to the center of the tension pulley, facilitates replacement with a fixed tensioner, and facilitates assembly. Is a technical issue.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, a support shaft fixed to a pulley support surface of a fixing member, a pulley support eccentrically supported by the support shaft, and a pulley support of the pulley support It consists of a tension pulley rotatably supported on the outside and a damper device that suppresses vibrations acting on the pulley support from the belt via the tension pulley. The tension adjustment spring that biases the belt toward the belt is installed.

[0007]

[Action]

 As described above, by providing the tension adjusting spring on the side opposite to the fixing member of the tension pulley, the distance from the pulley supporting surface of the fixing member to the center of the tension pulley can be shortened and the tension adjusting spring can be assembled. Since it can be done last, it is easy to assemble.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a first embodiment of a belt tension adjusting device according to the present invention. The support shaft 2 is screwed into the side surface of the engine block 1 as a fixing member.

A flanged sleeve 3 and a tapered pedestal 4 are sequentially fitted to the outside of the support shaft 2, and these parts are pressed against the engine block 1 by pressing the head 2 a of the support shaft 2. It is fixed.

A bush 5 is fitted on the outer side of the sleeve 3, and a pulley support 6 is rotatably supported on the outer side of the bush 5. The pulley support 6 is rotatably supported at the eccentric position by the bush 5, and a tension pulley 8 is rotatably supported outside the pulley support 6 via a bearing 7.

The tapered pedestal 4 is provided with an inclined cam surface 9 on a surface facing the pulley support body 6, while the pulley support body 6 is provided with a damper 10 opposed to the inclined cam surface 9. The piston 11 of the damper 10 is pressed against the inclined cam surface 9.

Here, the damper 10 slidably incorporates a piston 11 in an axial hole 12 formed in a pulley support 6, and a guide member 14 is provided in a cylinder chamber 13 formed at a rear end surface of the piston 11. A pressure chamber 15 is provided between the cylinder chamber 13 and the closed end of the cylinder chamber 13, and a spring 16 incorporated in the pressure chamber 15 presses the piston 11 against the inclined cam surface 9.

Further, the pressure chamber 15 and a reservoir chamber (not shown) formed in the pulley support 6 are communicated with each other by a passage 17 provided in the guide member 14, and the passage 17 is opened and closed at an end portion of the passage 17 on the pressure chamber 15 side. A check valve 18 is provided. Reference numeral 19 indicates a retainer that holds the check valve 18.

In the damper 10, when the piston 11 moves outward and the pressure force of the pressure chamber 15 becomes low, the check valve 18 opens the passage 17, and the working oil in the reservoir chamber flows from the passage 17 to the pressure chamber 15. It flows into 15, and the piston 11 is moved outwardly quickly. Conversely, when the piston 11 is pushed in and the pressure in the pressure chamber 15 rises, the check valve 18 closes the passage 17 and the working oil in the pressure chamber 15 moves between the piston 11 and the sliding surface of the guide member 14. It leaks more into the reservoir chamber and causes the piston 11 to retract at a low speed.

An engagement hole 20 is provided on the surface of the tapered pedestal 4, and a bent piece 22 at one end of a tension adjusting spring 21 a is inserted into the engagement hole 20. A gap is provided between the inner surfaces of 20.

The tension adjusting spring 21 a has a horseshoe shape, and the other end is connected to a connecting piece 24 provided at the tip of the arm 23. The arm 23 extends in the axial direction of the tension pulley 8, and a cylindrical portion 25 provided at the rear end thereof is fixed to the end of the pulley support 6 on the engine block 1 side by press fitting.

The tension adjusting spring 21a has a radial elastic force, and the elastic force urges the pulley support 6 toward the belt tension side.

The belt tension adjusting device shown in the embodiment has the above-described structure. When the belt 30 is loosened, the pulley support 6 is rotated about the support shaft 2 by the elastic force of the tension adjusting spring 21a, and the tension pulley 8 is rotated. Rotate in the direction in which the belt 30 is stretched.

At this time, the piston 11 of the damper 10 moves to the lower side of the inclined cam surface 9 along the inclined cam surface 9, and the check valve 18 opens the passage 17, so that the piston 11 moves outward. Move quickly.

Therefore, the rotation resistance of the tension pulley 8 is small, and the tension pulley 8 quickly rotates toward the belt tension side to absorb the slack of the belt 30.

On the other hand, when the tension of the belt 30 increases, the tension pulley 8 is pushed by the belt 30, and the pulley support 6 rotates around the support shaft 2 toward the belt slack side.

At this time, the piston 11 of the damper 10 moves along the inclined cam surface 9 to the higher side of the cam surface 9, so that the piston 11 is pushed in and the hydraulic oil in the pressure chamber 15 is compressed. Therefore, the piston 11 gradually retracts, absorbs the tension of the belt 30, and when the elastic force of the tension adjusting spring 21a and the tension of the belt 30 become equal, the pulley support 6 stops.

In the belt tension adjusting device according to the present invention, since the tension adjusting spring 21a is provided on the side opposite to the engine block 1 side of the tension pulley 8, the tension supporting pulley 1a of the engine block 1 moves to the tension pulley. The distance L to the center of 8 can be made smaller than the above-mentioned conventional one.

3 and 4 show a second embodiment of the belt tension adjusting device according to the present invention. In this embodiment, an example is shown in which the cylindrical portion 25 provided at the rear end of the arm 23 is press-fitted into the end of the pulley support 6 on the side opposite to the engine block. The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

FIGS. 5 and 6 show a third embodiment of the belt tension adjusting device according to the present invention. In this embodiment, a vortex-shaped tension adjusting spring 21b is used instead of the tension adjusting spring 21a in the second embodiment. The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

FIGS. 7 and 8 show a fourth embodiment of the belt tension adjusting device according to the present invention. In this embodiment, a coil-shaped tension adjusting spring 21c is used in place of the tension adjusting spring 21a in the first embodiment, one end of which is locked to the peripheral surface of the taper pedestal 4 and the other end of which is an arm 23. It is connected to the tip.

The other configurations and operations are the same as those of the first embodiment, and thus the description thereof will be omitted.

In the first to fourth embodiments, as a damper device that suppresses the vibration that acts on the pulley support 6 via the tension pulley 8 from the belt 30, a damper is provided on the inclined cam surface 9 of the taper pedestal 4. Although the swash plate type in which the piston 11 of 10 is pressed is shown, the damper device is not limited to this.

For example, as shown in FIG. 9, a large diameter portion 26 is formed at the end of the anti-engine block 1 of the sleeve 3 a provided outside the support shaft 2, and the large diameter portion 26 and the outside of the sleeve 3 a are formed. A closed space 27 may be formed between the pulley support 6a rotatably provided on the side and a viscous fluid may be sealed in the closed space 27.

[0030]

[Effect of the device]

 As described above, in the belt tension adjusting device according to the present invention, the tension adjusting spring for eccentrically rotating the pulley support toward the belt tension side is provided on the side opposite to the fixing member of the tension pulley. The distance from the supporting surface to the center of the tension pulley can be made smaller than the conventional one, and replacement with a fixed tension pulley is easy.

Further, since the tension adjusting spring can be assembled last, it is easy to assemble the tension adjusting device.

Furthermore, since the pulley support is urged in the belt tension direction by the tension adjusting spring that has elasticity in the radial direction, it is possible to secure a sufficient center movement distance of the tension pulley, and there is a large degree of freedom in design. ..

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of a belt tension adjusting device according to the present invention.

FIG. 2 is a vertical sectional side view of the above.

FIG. 3 is a front view showing a second embodiment of the belt tension adjusting device according to the present invention.

FIG. 4 is a vertical sectional side view of the above.

FIG. 5 is a front view showing a third embodiment of the belt tension adjusting device according to the present invention.

FIG. 6 is a side view of the above.

FIG. 7 is a front view showing a belt tension adjusting device according to a fourth embodiment of the present invention.

FIG. 8 is a side view of the above.

FIG. 9 is a vertical sectional front view showing another example of the damper device of the belt tension adjusting device.

[Explanation of symbols]

 1 Engine Block 1a Pulley Supporting Surface 2 Support Shaft 6 Pulley Supporting Body 8 Tension Pulley 10 Damper 11 Pistons 21a, 21b, 21c Tension Adjusting Spring

Claims (1)

[Scope of utility model registration request] 1. A support shaft fixed to a pulley supporting surface of a fixing member, a pulley support member whose eccentric position is rotatably supported by the support shaft, and a support member rotatably supported outside the pulley support member. It is composed of a tension pulley and a damper device that suppresses vibrations that act on the pulley support from the belt via the tension pulley, and urges the pulley support toward the belt tension side toward the non-fixing member side of the tension pulley. Belt tension adjusting device with tension adjusting spring.