JPH05248515A - Manufacture of resin pulley - Google Patents

Abstract

PURPOSE:To reduce the number of working processes and production cost by overlapping multiple bearings in which a small diameter part is formed on the outer periphery of the outer ring with their centers aligned with each other and forming them integrally with a pulley main body by injecting resin on the outer periphery of the bearings. CONSTITUTION:A ball bearing in which a grease capable of withstanding a high temperature >=80 deg.C is packed beforehand is used for a bearing 5, and a small diameter part 7 is formed on the outer peripheral edge of the outer ring 6 of the bearing 5 by cutting or chamfering the edge of the outer ring. Then an opening on both sides of the multiple bearings 5 which are overlapped with their centers aligned with each other is sealed, resin is injected on the outer periphery of the multiple bearings by an injection molding machine so that the resin is applied on the small diameter part 7 formed on the outer ring 6 to form a pulley main body 8, and the outer ring 6 is integrated with the pulley main body 8 through the small diameter part 7 to prevent the outer ring from coming off out of the pulley main body. Thus, even if a large lateral load is applied on the bearings 5, the bearings 5 are prevented from coming off out of the pulley main body 8 to cope sufficiently with the use for a pulley used for large cranes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resin pulley mainly used for large cranes.

[0002]

2. Description of the Related Art Conventionally, a pulley made of a synthetic resin, which is mainly used for a large-sized crane, is usually formed by injection molding a disk serving as a pulley body 1 as shown in FIG. A bearing insertion hole 3 into which the bearing 2 is inserted is machined, and a protruding step portion 4 for bearing the lateral load of the bearing 2 inserted into the bearing insertion hole 3 is formed at the center of the inside of the bearing insertion hole 3. Formed in the bearing insertion hole 3 from both sides,
It is manufactured by a process of press-fitting 2 into pressure contact with the protruding step portion 4.

[0003]

According to the above-mentioned conventional manufacturing method, a step of forming a disk serving as a pulley main body, a step of cutting a bearing insertion hole for inserting a bearing in the center of the disk, and a bearing Since there are three steps of inserting the bearing into the insertion hole, there is a problem that the manufacturing is troublesome and the cost becomes high.

Further, when a large lateral load is applied, the bearing may slip out on both sides, which is not sufficient as a pulley used for a large crane.

In view of the above points, it is an object of the present invention to reduce the manufacturing cost by making it strong against lateral load, sufficiently compatible with use in a large crane, and further simplifying the manufacturing process. The present invention provides a method for manufacturing the resin pulley.

[0006]

In order to achieve the above object, the present invention provides a plurality of bearings having a small diameter portion formed on the outer peripheral edge of an outer ring by rounding or chamfering so that their centers coincide with each other. Since the pulley main body is integrally molded by injecting resin so as to cover the small diameter portion formed on the outer peripheral edge of the outer ring of the bearing around the outer periphery of the plurality of superimposed bearings, the outer peripheral edge of the outer ring of the bearing The part of the pulley main body that has been applied to the small diameter part formed in the state where the bearing is held in the pulley main body, the bearing becomes integral with the pulley main body, and even if a lateral load is applied to this bearing, The portion of the pulley body that holds the formed small diameter portion prevents the bearing from coming out of the pulley body.

[0007]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows an example of a pulley manufactured according to the present invention. An embodiment of the present invention will be described with reference to the drawing.

First, as the bearing 5, a ball bearing in which grease capable of withstanding a high temperature of 80 ° C. or more is previously used is used, and a small diameter portion 7 is formed on the outer peripheral edge of the outer ring 6 of the bearing 5 by rounding or chamfering. In this way, the plurality of bearings 5 each having the small diameter portion 7 formed on the outer peripheral edge of the outer ring 6 are overlapped with their centers aligned. In the embodiment, two bearings 5 are overlapped with each other, but the present invention is not limited to this.

Next, after sealing the openings on both sides of the bearings 5 superposed on each other, the outer periphery of the bearings 5 is
A pulley main body 8 is formed by injecting resin by an injection molding machine so as to cover the small diameter portion 7 formed on the outer peripheral edge of the outer ring 6 of the bearing 5.

Therefore, the portion 9 of the pulley main body 8 which covers the small diameter portion 7 formed on the outer peripheral edge of the outer ring 6 of the bearing 5 is the bearing 5
The bearing 5 is integrated with the pulley main body 8 so that the bearing 5 is held in the pulley main body 8, and the bearing 5 is prevented from coming out of the pulley main body 8. Even if a large lateral load is applied to the bearing 5, the bearing 5 comes out of the pulley main body 8. There is no fear and it can be used as a pulley for large cranes.

[0011]

As described above, according to the method of manufacturing the resin pulley according to the present invention, the number of processing steps is smaller than that of the conventional method of manufacturing the resin pulley, and the processing work is much easier. Since the cost can be reduced and the manufactured pulley is strong against lateral load, and the bearing does not come out of the pulley body even when subjected to a large lateral load, it could not be used with conventional resin pulleys. It has the effect that it can be used for large cranes.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a resin pulley manufactured according to the present invention.

FIG. 2 is a vertical sectional view showing an example of a resin pulley manufactured by a conventional method.

[Explanation of symbols]

5 ……………………………………………………………………
…… Bearing 6 ……………………………………………………………………
…… Outer ring 7 ……………………………………………………………………
…… Small diameter part 8 ………………………………………………………………
...... Pulley body

Claims (1)

[Claims] 1. A plurality of bearings having a small diameter portion formed on the outer peripheral edge of the outer ring by rounding or chamfering so that their centers coincide with each other, and the outer periphery of the bearing is surrounded by the outer periphery of the plurality of bearings. A method for manufacturing a resin pulley, wherein a pulley main body is integrally molded by injecting a resin so as to cover a small diameter portion formed on an outer peripheral edge of the pulley.