JPH05106695A - Vibration reducing device for timing belt - Google Patents

Abstract

PURPOSE:To improve a life of a belt by suppressing vibration of the timing belt. CONSTITUTION:A free rotary unit 21 is arranged in a position separated a little from an external side surface of a timing belt 11 on its tension side. During operation of an engine, in a condition that no vibration is generated in the belt 11, it is not brought into contact with the free rotary unit 21, and it is stopped. When the belt 11 is started to vibrate, it comes into contact with the free rotary unit 21 to suppress vibration and also rotating the free rotary unit 21 in a running direction of the belt 11 to apply no unreasonable resistance to the belt 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping device that suppresses vibration of a timing belt used in a valve train of an engine.

[0002]

2. Description of the Related Art As shown in FIG. 9, a timing belt 1 used in a valve operating system of an engine is wound around a crank pulley 2 and cam pulleys 3 and 4 in an interlocking manner.
Use a tensioner or auto tensioner 5 on the slack side of
The tension of the timing belt 1 is adjusted.

The above-mentioned timing belt 1 is a portion on the tension side at a certain rotation speed during the operation of the engine, that is, between the cam pulley 4 and the crank pulley 2 or between the cam pulley 3 and the cam pulley 4, as shown by the alternate long and short dash line in FIG. As illustrated, the string vibration 1a is generated.

This vibration has a phenomenon of waviness and a twist phenomenon, and the latter twist phenomenon greatly affects the life of the belt.

Further, the phase of the crankshaft and the camshaft change due to the vibration, which also causes a reduction in the output of the engine.

As a conventional means for reducing the vibration of the timing belt as described above, as shown in FIG. 10, the timing belt 1 is rotated while always in contact with the outer surface of the belt 1 at the position on the tension side of the timing belt 1. The idle pulley 6 is installed.

[0007]

However, since the idle pulley 6 is constantly in contact with the timing belt 1 and rotates at high speed, durability is required and there is a problem that the structure is large and heavy.

Further, since the belt 1 is constantly pressed against the timing belt 1 and rotated while being bent, the timing belt 1 is unduly distorted, resulting in a problem that the life of the belt is shortened.

Therefore, it is an object of the present invention to provide a vibration damping device for a timing belt, which can prevent the vibration generated in the timing belt without causing the life of the belt and the output of the engine to decrease.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a timing belt used for an engine valve system at a position on the tension side of the timing belt when the vibration of the belt occurs. The configuration adopts a configuration in which a free rotating body is in contact with the outer side surface.

[0011]

When the timing belt does not vibrate during engine operation, the timing belt does not contact the free rotating body, the engine speed changes, and when the timing belt starts to vibrate, the belt contacts the free rotating body. , Vibration is suppressed.

At this time, since the free rotating body rotates, the timing belt is not subjected to excessive resistance. Also, the strain of the belt due to bending is small.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1 (A), the timing belt 11 used in the valve train of the engine is a crank pulley 1
2 and the cam pulleys 13 and 14 are wound so as to interlock,
A tensioner or an auto tensioner 15 is used on the slack side of the belt 11 to adjust the tension, and on the side facing the outer surface in the middle of the tension side of the timing belt 11, the vibration generated on the tension side is suppressed. A free rotating body 21 is arranged.

When the timing belt 11 is not vibrating during operation of the engine, the free rotating body 21 is shown in FIG.
As shown in (B), the belt 11 is arranged at a position slightly apart from the belt 11 so as not to come into contact with the outer surface of the belt 11, and the outer surface of the belt 11 contacts the outer peripheral surface of the free rotating body 21 when vibration starts. become.

2 to 8 show different examples of the specific structure of the free rotating body 21.

A first example of the free rotating body 21 shown in FIG. 2 is a fulcrum shaft bolt 23 screwed and fixed to the engine 22.
The thrust washer 24 is press-fitted and fixed to the root of the bolt as shown in FIG. 2 (A) as shown in FIG. 2 (A), and synthetic resin is used between the head 26 of the bolt 23 and the thrust washer 24. The free rotating body 21 formed into a cylindrical shape is externally fitted and inserted so as to be rotatable.

The fulcrum shaft bolt 23 is provided with a hexagonal hole 27 on the head side, and the portion to which the free rotating body 21 is fitted is induction hardened if necessary, and after the free rotating body 21 is inserted. Caulking the thrust washer 24 2
5 or by press-fitting so as not to come off, the components can be integrated, and there is an advantage that the assembly to the engine 22 can be easily performed.

The second example shown in FIG. 3 is a free rotating body 21.
Is made of metal, and a slide bearing 28 is incorporated between the fulcrum shaft bolt 23 and the rotating body 21. Third shown in FIG.
5 and the fourth example shown in FIG. 5, the collar 29 is used to mount the free rotating body 21 so that the mounting position can be adjusted. The inner diameter of the collar 29 to which the free rotating body 21 is fitted. Is formed to have a larger diameter than the outer diameter of the fulcrum shaft bolt 23, and the mounting position can be adjusted by the amount of clearance between the two as shown in FIGS.

The third example shown in FIG. 4 is a free rotating body 21.
A metal is used for the sliding bearing 30, and a slide bearing 30 is incorporated between the rotating body 21 and the collar 29. In the fourth example shown in FIG. 5, the free rotating body 21 is made of synthetic resin.

Next, in the fourth example, the fifth example and the sixth example shown in FIGS. 6 to 8, a shocking noise is generated between the free rotating body 21 and the end face of the fulcrum shaft bolt 23. The generation is prevented by the interposition of an elastic body.

That is, when the timing belt 11 vibrates while being vibrated, the free rotating body 21 is axially shocked to the fulcrum shaft bolt 23, and the free rotating body 21 and the fulcrum shaft bolt 23 are moved. A collision may occur between the end faces, which may cause a shocking noise.

Therefore, in the fourth example shown in FIG. 6 (A), the end of the free rotating body 21 and the thrust washer 24 in the mounted state of the free rotating body 21 are the same as in the first example shown in FIG. And the end of the free rotating body 21 and the fulcrum shaft bolt 2
A thrust washer 41 and a ring-shaped elastic body 42 such as rubber are respectively interposed between the head 26 and the head portion 26.

FIG. 6B is a diagram except that one end side of the mounting base 43 stacked on the engine 22 is fixed by tightening a bolt 44, and the fulcrum shaft bolt 23 is erected on the other end side of the mounting base 43. It is substantially the same as 6 (A).

As shown in FIG. 6B, the fulcrum shaft bolt 2
When the mounting base 43 is used for the arrangement of No. 3, the timing belt 11 is rotated by the rotation of the mounting base 43 with the bolt 44 as a fulcrum.
There is an advantage that the clearance between the free rotating body 21 and the free rotating body 21 can be freely adjusted.

Next, in the fifth example shown in FIGS. 7A and 7B, the fulcrum shaft bolt 23 is mounted in a state in which the free rotating body 21 is mounted as in the third example shown in FIG. Between the flange 29a of the collar 29 located on the head 26 side and the end of the free rotating body 21 (see FIG. 7A), or the collar 29.
A thrust washer 41 and an elastic body 42a using an O-ring are interposed between the both end flanges 29a, 29a and the free rotating body 21 (see FIG. 7B).

Further, in the sixth example shown in FIGS. 8A and 8B, one end portion of the collar 29 is in a state in which the free rotating body 21 is attached similarly to the fourth example shown in FIG. Between the flange 29a located at and the end of the free rotating body 21 (see FIG. 8).
(See (A)), or both end flanges 2 of the collar 29
Between 9a and 29a and the end of the free rotating body 21 (Fig. 8 (B)).
(See), a ring-shaped elastic body 42b made of a damping steel plate is interposed.

The vibration damping device of the present invention is constructed as described above, and as shown in FIG. 1, when the timing belt 11 does not vibrate during engine operation, the belt 11 contacts the free rotating body 21. Instead, the free rotating body 21 remains stopped.

When the engine speed changes and the timing belt 11 starts to vibrate, the outer surface of the belt 11 comes into contact with the free rotating body 21 and the vibration is suppressed. It rotates in the running direction and does not give excessive resistance to the belt 11.

Further, in each of the embodiments shown in FIGS. 6 to 8, the elastic body 42, the elastic body 42, even if the free rotating body 21 is shocked in the axial direction due to the twisting vibration of the timing belt 11. 42a or 42b can buffer the shock and prevent the generation of noise due to the shock.

[0031]

As described above, according to the present invention, since the free rotating body is arranged at a position slightly apart from the outer surface on the tension side of the timing belt, when the belt starts to vibrate, it comes into contact with the free rotating body to cause vibration. As a result, the vibration of the belt can be reduced and the service life can be extended.

Further, the free rotating body does not come into contact with the timing belt when the timing belt is not vibrating, and when the belt comes into contact with the timing belt, the free rotating body rotates in the belt running direction.

Further, since the free rotating body rotates only when the belt comes into contact and has a small action, the structure can be simplified in terms of strength, and vibration damping of the timing belt can be realized at a low weight and a low cost.

[Brief description of drawings]

FIG. 1A is a front view of a vibration damping device according to the present invention,
(B) is an enlarged front view of the main part of the above

2A is a cross-sectional view of a crimping method showing a first example of a free rotating body, and FIG. 2B is a cross-sectional view of a press-fitting method.

FIG. 3 is a cross-sectional view showing a second embodiment.

FIG. 4 (A) is a cross-sectional view showing a third embodiment, (B).
Is a cross-sectional view showing the same position adjustment state as above.

5A is a cross-sectional view showing a fourth embodiment, FIG.
Is a cross-sectional view showing the same position adjustment state as above.

FIG. 6A is a cross sectional view showing a fifth embodiment, and FIG.
Is a cross-sectional view showing a different example of mounting the fulcrum shaft prevention in the same as above.

FIG. 7A is a cross sectional view showing a sixth embodiment, and FIG.
Is a cross-sectional view showing the same position adjustment state as above.

FIG. 8A is a cross sectional view showing a seventh embodiment, and FIG.
Is a cross-sectional view showing the same position adjustment state as above.

9 is a front view showing a timing belt winding state of the engine valve system. FIG.

FIG. 10 is a front view showing a conventional vibration damping means.

[Explanation of symbols]

 11 Timing Belt 21 Free Rotating Body 23 Support Shaft Bolt

Claims (1)

[Claims] 1. A vibration damping device for a timing belt, comprising a free rotating body, which is brought into contact with an outer surface of the timing belt when vibration of the timing belt is generated, at a position on the tension side of a timing belt used for a valve train of an engine.