JPH0614609U - Synthetic resin pulley - Google Patents

Abstract

(57) [Abstract] [Purpose] In a synthetic resin pulley having a large number of radial ribs, it is to eliminate the insufficient strength of the ribs in which a weld line occurs. [Structure] Three or more odd-numbered ribs 6 and 7 are present between two mutually adjacent gate marks 8, and the ribs 6 equidistant from both gate marks 8 are thicker than other ribs 7. By forming it thick, the flow of the molten resin in the portion of the rib 6 that causes the weld line was improved, and the adhesion strength was increased.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a synthetic resin pulley.

[0002]

[Prior art]

 A pulley in which a synthetic resin pulley is integrally provided around a rolling bearing is conventionally known as, for example, a pulley for a timing belt of an automobile engine or a pulley for driving an auxiliary machine. In such a pulley, a large number of radial ribs are formed at regular intervals between the boss and the rim in order to avoid sink marks during molding and to make the pulley have a uniform thickness.

When molding such a pulley with a synthetic resin, molten resin is injected from a plurality of gates of a molding die, but the molten resin injected from gates adjacent to each other is a cavity of the molding die. Flow inside and join at a certain position to form a weld line.

At the above-mentioned joining points, particularly in the portion where the cavity is narrow and the resin flow is bad, the temperature of the molten resin becomes low, so that even if they join, the mutual fusion becomes insufficient. Therefore, the adhesion strength between the resins on the weld line is insufficient. Further, when the resin is filled with the reinforced fiber, the fibers are divided and oriented on both sides of the weld line, which causes a decrease in strength.

Therefore, the present invention aims to improve the strength by improving the adhesion between the resins in the weld line.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention comprises a rolling bearing and a synthetic resin pulley portion, and the pulley portion is integrated with the boss in which the rolling bearing is fitted integrally with the inner diameter surface and the outer periphery of the boss. A synthetic resin in which a plurality of radial ribs extending over the boss and the rim are formed at regular intervals, and a plurality of gate marks are present on the boss at regular intervals. In the pulley, there are three or more odd-numbered ribs between two adjacent gate marks, and the ribs equidistant from both gate marks are made thicker than other ribs. It was done.

On the other hand, depending on the type of pulley, a disc portion is formed on the outer periphery of the boss and a rim is integrally provided on the outer periphery of the disc portion. In some cases, a large number of radial ribs are formed at regular intervals, and there is a gate mark on the disk part. In this case as well, two gate marks that are adjacent to each other as in the case above. There are three or more odd-numbered ribs between them, and the ribs equidistant from both gate marks are made thicker than the other ribs.

[0008]

[Action]

 In any of the above synthetic resin pulleys, the molten resin injected from two adjacent gates merges in a cavity forming a rib that is equidistant from the gates. Since this cavity is formed wider than the other cavity for rib formation adjacent thereto, the flow of the molten resin is good. As a result, the resin joins while the temperature of the resin is sufficiently high, and the joined resins fuse together, improving the adhesion strength at the weld line.

[0009]

【Example】

 The synthetic resin pulley of the first embodiment shown in FIGS. 1 and 2 is used, for example, as a timing belt pulley. This pulley comprises a ball bearing 1 and a synthetic resin pulley portion 2 integrated around the ball bearing 1. The pulley portion 2 is composed of a boss 4 fitted and integrated with the outer periphery of the outer ring 3 of the ball bearing 1, and a rim 5 integrally formed around the boss 4.

A large number of radial ribs 6 and 7 are formed between the boss 4 and the rim 5 on both sides of the pulley portion 2 at regular intervals. Among these ribs 6 and 7, the ribs 6 having a wall thickness that is present at a constant interval of one in three ribs are formed to be 1.2 to 2.0 times thicker than other normal ribs 7. It

A gate mark 8 is present on one surface of the boss 4 in the middle of the adjacent normal ribs 7. In other words, there are three ribs 6 and 7 between two adjacent gate marks 8 on one side of the boss 4, and the rib 6 equidistant from both gate marks 8 is larger than the other rib 7. It is formed thick.

When molding the pulley as described above, the molten resin injected from the gate of the molding die flows into the cavity of the molding die from the portion of each gate mark 8, and two adjacent gate marks are formed. The cavities forming the thick ribs 6 equidistant from the portion 8 join to form a weld line.

However, since the cavity in this portion has a wide width corresponding to the thick rib 6, the flow of the resin is good, and therefore the time until the merging is shortened. Therefore, the temperature of the molten resin is prevented from lowering, and the fusion progresses by that amount, and even if a weld line occurs, the adhesion strength at the weld line is improved compared to the case where all the ribs are formed by normal ribs 7. .

Further, even if the reinforcing fibers are mixed with the resin, the fusion of the resin progresses in the weld line portion, and as a result, the reinforcing fibers cross the weld line and secure the strength.

In the above-described embodiment, three ribs 6 and 7 are formed between two adjacent gate marks 8 and the rib 6 at the center has a wall thickness. (For example, 5 ribs) may be formed, and the rib 6 at the center thereof may be thick.

Next, the second embodiment shown in FIGS. 3 and 4 is used, for example, as an accessory drive pulley of an automobile engine, and this pulley is provided with a disk portion 9 on the outer periphery of the boss 4. The rim 5 is formed on the outer circumference of the disc portion 9. A large number of ribs 6 and 7 are provided radially between the boss 4 and the rim 5 on the disc portion 9, and the disc mark 9 exists on the disc portion 9. Three ribs 6 and 7 are formed between two adjacent gate marks 8 and the central one is formed to be thick. Other configurations and operations are the same as those of the first embodiment described above. It is the same.

[0017]

[Effect of device]

 As described above, in the present invention, since the rib that causes the weld line is formed thicker than the normal rib, the flow of the molten resin in the cavity that molds the rib is improved, and the adhesion strength at the weld line portion is improved. To do. Further, the strength of the weld line portion is increased by the thick rib itself, so that reliability in strength is improved.

[Brief description of drawings]

FIG. 1 is a front view of the first embodiment.

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

FIG. 3 is a partially omitted front view of the second embodiment.

FIG. 4 is a partially omitted sectional view of the same as above.

[Explanation of symbols]

 1 Ball Bearing 2 Pulley Part 3 Outer Ring 4 Boss 5 Rim 6 Rib 7 Rib 8 Gate Mark 9 Disc Part

Claims (2)

[Scope of utility model registration request] 1. A rolling bearing and a synthetic resin pulley portion, wherein the pulley portion comprises a boss in which the rolling bearing is fitted and integrated with an inner diameter surface, and a rim integrally provided on the outer periphery of the boss. In the synthetic resin pulley having a large number of radial ribs extending over the boss and the rim at regular intervals and having a plurality of gate marks at regular intervals on the boss, two ribs adjacent to each other are provided. A synthetic resin pulley characterized in that three or more odd number of ribs are present between the gate marks, and ribs equidistant from both gate marks are formed to be thicker than the other ribs. 2. A rolling bearing and a synthetic resin pulley portion, wherein the pulley portion has a boss in which the rolling bearing is fitted and integrated with an inner diameter surface, and a disc portion integrally provided on the outer periphery of the boss. And a rim integrally provided on the outer periphery of the disc part, and a large number of radial ribs extending over the boss and the rim are formed at a constant interval on the disc part, and the disc part has a constant interval. In a synthetic resin pulley in which a large number of gate marks are present, three or more odd-numbered ribs are present between two mutually adjacent gate marks, and the ribs are equidistant from both gate marks. Is made thicker than other ribs, a synthetic resin pulley.