JP2880564B2 - Resin pulley - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is formed by injection-molding a plurality of ribs extending radially around a boss, and a rim formed around the tip of each rib. It relates to a resin pulley.

[Prior art] Conventionally, as this kind of resin pulley, for example,
A technique disclosed in Japanese Patent No. 85762 is known.

In this technique, when injection molding a resin pulley, the thickness of the ribs is gradually increased as the distance from the resin injection gate in the circumferential direction is increased, and the pitch of each rib is sequentially reduced as the distance from the gate in the circumferential direction is increased. I was
As a result, the amount and speed of the resin reaching the rim (the outer periphery of the pulley) from the gate are made uniform, so that the cooling rate of the resin is made uniform. I was

[Problems to be Solved by the Invention] However, in general, in the case of a resin pulley, there is a difference in resin shrinkage (sink) between a rib and a portion having no rib during cooling after molding. It will take shape.

Therefore, in the pulley of the prior art, since the pitch of each rib has a regularity of sequentially increasing and decreasing along the circumferential direction, the pitch of each surface of the outer periphery of the polygonal pulley is changed in the circumferential direction. Has a regularity that increases and decreases sequentially. Therefore, when the belt is run with the belt in contact with the outer peripheral surface of the pulley in order to rotate the pulley, the belt hits the outer peripheral surface of the pulley, and the belt is hit with a periodicity. Are amplified by resonance. As a result, there is a problem that abnormal noise is generated or strength of the pulley itself is reduced. In addition, the wind noise of the ribs also changes periodically with the rotation of the pulley, so that a humming sound having a certain frequency is generated, causing an increase in noise.

The present invention has been made in view of the above-described circumstances, and has an object to reduce resonance in vibration when a belt hits a pulley when the belt is run while contacting the belt with the outer peripheral surface of the pulley. An object of the present invention is to provide a resin pulley capable of suppressing generation of abnormal noise and reduction in strength and reducing wind noise of a rib.

[Means for Solving the Problems] In order to achieve the above object, in the present invention,
In a resin pulley composed of a plurality of ribs extending radially around a boss and a rim that goes around the tip of each rib, the pitch between adjacent ribs is all unequal, and Equal pitches are randomly arranged.

[Operation] According to the above configuration, the intervals between adjacent ribs are all unequal pitches, and the unequal pitches are arranged randomly, so that the rim after resin molding, that is, the outer peripheral surface of the pulley, It becomes a polygonal shape without regularity. For this reason, when traveling while the belt is in contact with the outer peripheral surface of the pulley,
The belt no longer hits the pulley with periodicity,
Vibration is not amplified due to the loss of vibration resonance caused by hitting. In addition, the wind noise of the ribs has no periodicity.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing a resin pulley 1 of this embodiment,
FIG. 2 is a perspective view thereof.

The injection-molded pulley 1 has a plurality of (in this case, six) ribs 3a, 3b, 3c, 3d, 3e, 3 extending radially around the boss 2.
f and an annular rim 4 around the tip of each of the ribs 3a to 3f. In addition, each adjacent rib 3a ~
During 3f, angular intervals of different sizes (unequal pitch)
P1, P2, P3, P4, P5, P6, each unequal pitch P1 ~ P6
Are arranged randomly without specifying the order. Also in the pulley 1 of this embodiment, there is a difference in the resin shrinkage (shrinkage) during cooling after molding between the ribs 3a to 3f and the portion without the ribs 3a to 3f. 4 has a slightly polygonal outer periphery.

This resin pulley 1 is used as an idler pulley for reducing the engine weight. For example, as shown in FIG. 3, in order to adjust the tension of the timing belt 7 mounted between the cam 5 and the crankshaft 6, the timing belt 7 is pressed against the timing belt 7 and rotatably supported. As shown in the figure, in order to adjust the tension of the V-ribbed belt 10 mounted between the auxiliary device 8 and the crankshaft 9, the V-ribbed belt 10 is pressed against the V-ribbed belt 10 and rotatably supported.

Therefore, in the pulley 1 of this embodiment, each rib
3a to 3f are all irregular pitches P1 to P6 and the irregular pitches P1 to P6 are arranged randomly, so that the outer peripheral surface of the rim 4 after resin molding has a polygonal shape without regularity Becomes

For this reason, when the timing belt 7 and the V-ribbed belt 10 are run while being pressed against the outer peripheral surface of the rim 4 as shown in FIGS. No more hitting. In other words, each belt
The continuous timing at which 7,10 hits the pulley 1 becomes disorderly.

As a result, the vibration level of the pulley 1 due to the beating of the belts 7 and 10 changes randomly and the resonance does not occur, and the vibration is not amplified by the resonance. Therefore, pulley 1
The generation of abnormal noise caused by the vibration amplification of the above can be suppressed. In addition, the strength of the pulley 1 itself can be prevented from being reduced due to the vibration amplification, and the reliability of the lightweight resin pulley 1 can be improved.

Further, when the pulley 1 rotates, the change of the wind noise of each of the ribs 3a to 3f has no periodicity and its frequency is disturbed, so that the generation of the growling noise can be suppressed and the wind noise can be reduced.

The present invention is not limited to the above-described embodiment, and may be implemented by appropriately changing a part of the configuration without departing from the spirit of the invention, for example, by appropriately changing the number of ribs. .

[Effects of the Invention] As described above in detail, according to the present invention, all the adjacent ribs are formed at irregular pitches, and the irregular pitches are randomly arranged. In the case of running while making contact, the resonance of the vibration when the belt hits the pulley can be reduced, and the generation of abnormal noise and reduction in strength can be suppressed, and the wind noise of the rib can be reduced. It has an excellent effect of being able to do it.

[Brief description of the drawings]

FIG. 1 is a front view showing a resin pulley according to an embodiment of the present invention, FIG. 2 is a perspective view showing the same resin pulley, and FIGS. 3 and 4 show examples of using the resin pulley. FIG. In the figure, 2 is a boss, 3a to 3f are ribs, 4 is a rim, and P1 to P6 are unequal pitches.

Continuation of the front page (56) References Japanese Utility Model Showa 49-89552 (JP, U) Japanese Utility Model Showa 60-142352 (JP, U) Japanese Utility Model Showa 61-85762 (JP, U) Japanese Utility Model Showa 62-128249 (JP) , U) (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 55/36 F16H 55/48 F16F 15/10

Claims (1)

(57) [Claims] 1. A resin pulley comprising: a plurality of ribs extending radially around a boss; and a rim formed around the tip of each of the ribs. And the irregular pitches are randomly arranged.