JP2002266991A - Bearing with resin pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage of a resin pulley 10 by restricting occurrence of cracks on the resin pulley 10 with welds 42 and 43 serving as starting points, on a bearing with resin pulley favorable for use in a belt for driving vehicular auxiliaries or the like. SOLUTION: This bearing with resin pulley is constituted by integrally forming the resin pulley 10 on the outer periphery of an outer ring in a rolling bearing. In between adjacent portions of one end surface of an inside-diameter cylindrical portion 11 of the resin pulley 10 and a reinforcing rib 15a, and a second and a third reinforcing ribs 15b and 15c adjacent to the primary reinforcing rib 15a, a pair of gates 40 and 41 respectively molded are located sequentially in the peripheral direction of the resin pulley 10. At the intersection of the reinforcing ribs 15 and the inside-diameter cylindrical portion 11, the welds 42 and 43 are molded with inclinations to the radial directions of the resin pulley 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timing belt for an automobile, an auxiliary drive belt, and the like, which is provided with a resin pulley suitable for an idler bearing, a tensioner bearing, and the like used for adjusting a belt tension and changing a traveling path. Bearings.

[0002]

2. Description of the Related Art Conventionally, bearings used as accessory driving belts for transmitting the rotational power of an engine to the accessories of an automobile have been designed to reduce the weight and cost.
A bearing with a resin pulley is used, in which a synthetic resin pulley is integrally formed on the outer peripheral surface of a metal outer ring of a rolling bearing.

An example of a conventional resin pulley 10 of a bearing with a resin pulley will be described with reference to FIGS. 1 and 2. FIG.
The resin pulley 10 is provided with an inner cylindrical portion 11 fixed to an outer ring of a rolling bearing (not shown), an outer cylindrical portion 12 having a belt guide surface 13, and provided between the inner cylindrical portion 11 and the outer cylindrical portion 12. And a plurality of reinforcing ribs 15 radially formed on both surfaces of the disk portion 14 at predetermined intervals.

[0004]

Conventionally, a resin pulley 10
Are manufactured by injection molding of synthetic resin. That is, the rolling bearing or its outer ring is centered and fixed in a molding die, and the cavity of the molding die is filled with a molten resin through a resin injection gate, solidified, and then opened to perform molding.

However, when the resin pulley 10 is injection-molded, the molten resin injected from each gate merges in the mold, and a weld occurs at the junction. Welding often occurs, for example, on the inner diameter cylindrical portion 11 near the outer ring of the rolling bearing on the end surface opposite to the gate side end surface.

[0006] When a weld is generated in the inner cylindrical portion 11,
Due to the difference in linear expansion coefficient between the resin pulley 10 and the metal outer ring, the resin pulley 1
There is a problem that a crack occurs in the resin pulley 10 and the resin pulley 10 is damaged.

In particular, when the direction in which the weld is formed is substantially parallel to the direction of thermal expansion that extends radially outward from the rolling bearing, cracks are likely to occur in the resin pulley 10.

An object of the present invention is to provide a bearing with a resin pulley that can suppress the occurrence of cracks in a resin pulley starting from a weld portion and prevent the resin pulley from being damaged.

[0009]

A first aspect of the present invention is a bearing with a resin pulley in which a resin pulley is integrally formed on an outer peripheral surface of an outer ring of a rolling bearing. An inner diameter cylindrical portion fixed to the outer ring, an outer diameter cylindrical portion having a belt guide surface, a disk portion provided between the inner and outer diameter cylindrical portions, and a plurality of reinforcing ribs radially formed on the disk portion. A weld is formed at the intersection of the reinforcing rib and the inner diameter cylindrical portion by being inclined with respect to the radial direction of the resin pulley.

According to the bearing with the resin pulley of the first aspect of the present invention, the weld is formed at the intersection of the reinforcing rib and the inner diameter cylindrical portion by being inclined with respect to the radial direction of the resin pulley. However, it does not become substantially parallel to the direction of thermal expansion that extends radially outward from the rolling bearing, and since the weld joint area increases, the linear expansion coefficient between the resin pulley and the metal outer ring increases. Due to the difference, it is possible to suppress the occurrence of cracks in the resin pulley starting from the weld portion. Moreover, since a weld is formed in the thick reinforcing rib portion, it is possible to further suppress the occurrence of cracks in the resin pulley.

A second aspect of the present invention is a bearing with a resin pulley in which a resin pulley is integrally formed on an outer peripheral surface of an outer ring of a rolling bearing, wherein the resin pulley is fixed to an outer ring of the rolling bearing. Portion, an outer cylindrical portion having a belt guide surface, a disk portion provided between the inner and outer cylindrical portions, and a plurality of reinforcing ribs formed radially on the disk portion, the inner cylindrical portion A pair of gates respectively formed between an adjacent portion of the one end surface of the resin pulley and the second and third reinforcing ribs adjacent to the first reinforcing rib are connected to the resin pulley. They are arranged sequentially in the circumferential direction.

According to the bearing with a resin pulley of claim 2 of the present invention, a portion of the inner diameter cylindrical portion adjacent to the first reinforcing rib is provided;
By forming a pair of gates between the second and third reinforcing ribs sequentially adjacent to the first reinforcing rib, the molten resin flowing from each of the gates becomes the second reinforcing rib and the inner diameter cylindrical portion. And a weld is formed inclining with respect to the radial direction of the resin pulley. In this manner, the direction in which the weld is formed is not substantially parallel to the direction of thermal expansion that extends radially outward from the rolling bearing, and the weld joint area is increased, so that the resin pulley and the metal pulley are formed. It is possible to suppress the occurrence of cracks in the resin pulley starting from the weld portion due to the difference in the linear expansion coefficient from the outer ring. Moreover, since a weld is formed in the thick reinforcing rib portion, it is possible to further suppress the occurrence of cracks in the resin pulley.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
This will be described with reference to FIGS. The structure of the resin pulley 10 of the bearing with a resin pulley is the same as the example shown in FIGS.

FIG. 3 is a front view of a bearing 20 with a resin pulley formed by integrally molding a resin pulley 10 on the outer periphery of a rolling bearing 30. The rolling bearing 30 includes an inner ring 31, an outer ring 32, a rolling element 33 of balls and rollers, and the like. A resin pulley 10 is provided by fixing the inner diameter cylindrical portion 11 to the outer ring 32. Gates 40 and 41 are formed on one end surface of the inner cylindrical portion 11 of the resin pulley 10.

FIG. 4 is a partially enlarged front view of the resin pulley 10. The gate 40 is formed at a portion of the inner diameter cylindrical portion 11 adjacent to the first reinforcing rib 15a. Further, the gate 41 includes a second reinforcing rib 15b and a third reinforcing rib 15 that are sequentially adjacent to the first reinforcing rib 15a clockwise.
The gap is formed on the inner diameter cylindrical portion 11 between c. Similarly, the gates 40 and 41 are sequentially arranged at equal intervals in the circumferential direction of the resin pulley 10.

FIG. 5 is a sectional view showing a step of forming the resin pulley 10. The mold for molding the resin pulley 10 includes an upper mold 50 and a lower mold 51, and these upper and lower molds 50, 51
The rolling bearing 30 is centered and fixed therebetween, and the cavity around it is filled with molten resin.

Here, 52 is a cavity for the inner cylindrical portion 11, 53 is a cavity for the outer cylindrical portion 12, 54 is a cavity for the disk portion 14, and 55 is a cavity for the reinforcing rib 15. Further, the cavity 52 for the inner diameter cylindrical portion has a gate hole 5 corresponding to the location where the gates 40 and 41 are formed.
6 is open. Incidentally, 57 is a runner.

When the molten resin is filled from the gate hole 56 through the runner 57 with the rolling bearing 30 being set, the molten resin flows through the cavity 52 for the inner diameter cylindrical portion, and the cavity 54 for the disk portion and The cavity 53 for the outer diameter cylindrical portion extends to the cavity 55 for the reinforcing rib.
And each cavity 52, 53, 54, 55 is filled.

As shown in FIG. 4, the molten resin filled from each gate hole 56 is filled with reinforcing ribs 15 and inner cylindrical portion 11.
Merge in the cavity at the intersection with.

That is, the molten resin filled from the gate hole 56 corresponding to the gate 40 flows inside the cavity 52 for the inner diameter cylindrical portion in the left and right direction in the circumferential direction, and also the cavity 54 for the disk portion and the adjacent first portion. Reinforcement rib and 15a
To the cavity 55 for the reinforcing rib corresponding to the above.

The gate hole 56 corresponding to the gate 41
The molten resin filled in from inside flows inside the cavity 52 for the inner diameter cylindrical portion to the left and right in the circumferential direction and spreads to the cavity 54 for the disk portion. Further, at the portion of the cavity 55 for the reinforcing rib corresponding to the second reinforcing rib 15b, the molten resin is merged with the molten resin filled from the gate hole 56 corresponding to the gate 40. The flowability of the molten resin is higher in the thick part of the cavity than in the thin part of the cavity, so that the molten resin easily flows in the cavity 55 for the reinforcing rib, and the flow of the molten resin changes, and Flows into the reinforcing rib cavity 55 corresponding to the reinforcing rib 15b. As a result, at the intersection between the second reinforcing rib 15b and the inner diameter cylindrical portion 11, a weld 42 is formed inclined with respect to the radial direction of the resin pulley 10.

Similarly, at the intersection between the third reinforcing rib 15c and the inner diameter cylindrical portion 11, the molten resin filled from the gate hole 56 corresponding to the gate 41 and the gate hole corresponding to the next gate 40 are formed. The molten resin filled from 56 merges, and a weld 43 is formed inclined with respect to the radial direction of the resin pulley 10. Hereinafter, the welds 42 and 43 are formed so as to be sequentially inclined with respect to the radial direction of the resin pulley 10, that is, not substantially parallel to the direction P of thermal expansion extending radially outward from the rolling bearing 30. .

It should be noted that the welds 42 and 43 are
5 at the intersection of the inner diameter cylindrical portion 11 and the resin pulley 1
0, the first reinforcing rib 1 of the inner diameter cylindrical portion 11 as in the above-described embodiment.
5a, the second and third reinforcing ribs 15b,
The position and number of gates can be arbitrarily selected without being limited to the gates 40 and 41 formed during 15c.

In the above embodiment, the gate 4
Although 1 is formed in the central portion between the second and third reinforcing ribs 15b, 15c, it may be formed between the second and third reinforcing ribs 15b, 15c, and need not be formed particularly in the center. .

[0025]

According to the bearing with a resin pulley of the present invention,
It is possible to obtain the effect of suppressing the occurrence of cracks in the resin pulley starting from the weld portion and preventing the resin pulley from being damaged.

[Brief description of the drawings]

FIG. 1 is a front view of a resin pulley.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a front view of the bearing with a resin pulley according to the embodiment of the present invention.

FIG. 4 is a partially enlarged front view of a resin pulley according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view of a step of forming a resin pulley according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Resin pulley 11 Inner diameter cylindrical part 12 Outer diameter cylindrical part 13 Belt guide surface 14 Disk part 15 Reinforcement rib 20 Bearing with resin pulley 30 Rolling bearing 31 Inner ring 32 Outer ring 33 Rolling element 40,41 Gate 42,43 Weld

Claims (2)

[Claims] 1. A bearing with a resin pulley integrally formed with a resin pulley on an outer peripheral surface of an outer ring of a rolling bearing, wherein the resin pulley has an inner diameter cylindrical portion fixed to the outer ring of the rolling bearing, and a belt guide surface. Having an outer diameter cylindrical portion having a disk portion provided between the inner and outer diameter cylindrical portions and a plurality of reinforcing ribs radially formed on the disk portion, wherein the reinforcing ribs and the inner diameter cylindrical portion have A bearing with a resin pulley in which a weld is formed at an intersection with respect to a radial direction of the resin pulley. 2. A bearing with a resin pulley in which a resin pulley is integrally formed on an outer peripheral surface of an outer ring of a rolling bearing, wherein the resin pulley has an inner cylindrical portion fixed to the outer ring of the rolling bearing, and a belt guide surface. Having an outer diameter cylindrical portion having a disk portion provided between the inner and outer diameter cylindrical portions and a plurality of reinforcing ribs formed radially on the disk portion, and a first end face of the inner diameter cylindrical portion, An adjacent portion to the first reinforcing rib, and second and third portions sequentially adjacent to the first reinforcing rib.
A pair of gates respectively formed between the reinforcing ribs of
A bearing with a resin pulley sequentially arranged in a circumferential direction of the resin pulley.