JPH1151158A - Timing pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release air in the circumferential direction of a pulley and to avoid the damage and the reduction in transmission efficiency of a belt so as to effectively reduce the noise by forming a slit extended in the circumferential direction in a substantially intermediate part in the direction of a pulley axis of a tooth crest part. SOLUTION: For example, one slit 5 extended in the circumferential direction, namely, in the orthogonal direction to the direction of a pulley axis is formed in a substantially intermediate part in the direction of the pulley axis of each tooth crest part 4a in an oil pump pulley 4 made of a metallic material as one example of various pulleys (crank, cam, oil pump, etc.), of an automobile engine. In this way, at the time of meshing with a timing belt 3 made of an elastic material, an air escape route is ensured in the circumferential direction of the oil pump pulley 4 by the slit 5 to exhaust the meshed air quickly so as to suppress the generation of noise. At this time, since it can do with the slit 5 which is small in its width, a tooth contact width is scarcely affected, and the adverse effects do not occur in load to the timing belt 3 and transmission efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pulley for a timing belt of an automobile engine or the like.

[0002]

2. Description of the Related Art In an automobile engine, a timing belt is used to transmit a driving force to various auxiliary machines. For example, as shown in FIG. 3, the cam pulley 2 made of a metal material fixed to the shaft end of the camshaft 1 and the crank pulley made of a metal material fixed to the shaft end of a crankshaft (not shown) are made of an elastic material. The timing belt 3 is wound around with a predetermined tension.

[0003]

However, when the above-mentioned timing belt and the various pulleys engage with each other, air is caught between them and noise is generated when the bitten air is released as the pulley rotates. There is a problem that a compression sound and a burst sound are generated.

As a countermeasure, measures such as tapering a pulley have been taken to secure an escape path for air. However, there is a risk that the belt may be damaged due to one side contact and transmission efficiency may be reduced.

Also, Japanese Utility Model Laid-Open No. 49-124457,
JP-A-54-032243 and JP-B-57-01
In Japanese Patent No. 2901 and the like, a relief groove or the like is provided at the end of the pulley to release air in the axial direction of the pulley to reduce noise generation, but the effect is still insufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a timing pulley capable of effectively reducing noise by avoiding damage to a belt and lowering transmission efficiency by allowing air to escape in a circumferential direction of the pulley. is there.

[0007]

In order to achieve the above object, a timing pulley according to a first aspect of the present invention is a pulley for a timing belt. The slit is formed to extend. According to this, the air can be quickly released in the circumferential direction of the pulley, and the generation of noise can be reduced.

In a timing pulley according to a second aspect of the present invention, the slit extends to the root of the tooth. According to this, air can be released more quickly in the circumferential direction of the pulley than in the first embodiment.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a timing pulley according to the present invention will be described in detail with reference to the drawings using embodiments.

FIG. 1 is a structural explanatory view showing one embodiment of a timing pulley according to the present invention, and FIG.

As shown in FIG. 1, an oil pump pulley 4 made of a metal material as an example of various pulleys (cranks, cams, oil pumps, etc.) of an automobile engine is provided with pulleys of respective toothed portions 4a. A slit 5 extending in the circumferential direction (a direction perpendicular to the pulley axis direction) is formed substantially in the middle of the axial direction.

The slit 5 may be integrally formed at the time of forming the pulley, or may be formed by machining. Further, the slit 5 may be formed over several lines. Further, the slit 5 may be formed deeply so as to reach the root portion.

With this configuration, as shown in FIG. 2, at the time of engagement with the timing belt 3 made of an elastic material, an air escape path is secured in the circumferential direction of the oil pump pulley 4 by the slit 5, so that the The entrapped air is quickly discharged, thereby suppressing noise generation.

At this time, since the width of the slit 5 can be small, there is little influence on the tooth contact width, and there is no adverse effect on the load on the timing belt 3 and the transmission efficiency.

The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0016]

As described above, according to the first aspect of the present invention, in the pulley for the timing belt, the slit extending in the circumferential direction is formed substantially at the intermediate portion of the tooth ridge portion in the pulley axial direction, so that air is released. The pulley can be quickly released in the circumferential direction, thereby avoiding damage to the belt and lowering the transmission efficiency, thereby effectively reducing noise generation.

According to the second aspect of the invention, since the slit extends to the root of the tooth, air can escape more quickly in the circumferential direction of the pulley than in the first aspect of the invention.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view showing an embodiment of a timing pulley according to the present invention.

FIG. 2 is an operation explanatory view of the same.

FIG. 3 is a perspective view showing a conventional engagement between a cam pulley and a timing belt.

[Explanation of symbols]

 3 Timing belt 4 Oil pump pulley 4a Tooth ridge 5 Slit

Claims (2)

[Claims] 1. A timing pulley comprising a timing belt pulley, wherein a slit extending in a circumferential direction is formed substantially at an intermediate portion of the tooth ridge portion in the pulley axial direction. 2. The timing pulley according to claim 1, wherein the slit extends to a root portion.