JPH0783226A - Resin molded article incorporated needle roller bearing device - Google Patents

Abstract

PURPOSE:To provide a needle roller bearing device incorporating a resin molded article, capable of managing the gap between a needle roller and a shaft at high precision, attempting low cost and low torque and being used in a pulley in a driving part of business machine, for example, a copying machine, etc. CONSTITUTION:In this bearing device, a bearing fitting backup ring 2 is provided on a resin molded article 1, and a needle roller bearing 3 is pressed in the backup ring 2. The needle roller bearing 3 is the shell-type and provided with no inner race, and wherein a cage provided with a needle roller 7 is incorporated in an outer race 4 composed of a deep contracted molded article such as a steel plate. The resin molded article 1 serves as a pulley, a gear and a toothed pulley. It is desirable to use iron member having same materials as the outer race 4 of the needle roller bearing 3 or sintered alloy of iron group as the materials of the backup ring 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a needle roller bearing device incorporating a resin molded product used in a drive section of office equipment such as a copying machine, a laser printer and a facsimile.

[0002]

2. Description of the Related Art Conventionally, a pulley and a gear in which a resin molded product is mounted on a ball bearing or a sliding bearing (sintered bearing) are used in a drive unit for office equipment such as a copying machine, a laser printer, and a facsimile. For example, a resin wire pulley used for the scanner drive wire of a plain paper copier,
Alternatively, the idler gear is manufactured by simultaneously molding or press-fitting a resin molded product on the outer diameter surface of the ball bearing, or by press-fitting the resin molded product into a sintered bearing.

[0003]

However, when a ball bearing is used, the cost of the embedded product becomes high due to the high bearing cost. Further, the use of the slide bearing has a disadvantage in terms of torque as compared with the rolling bearing.

Therefore, it has been considered to use a shell type needle roller bearing which is inexpensive and can be obtained as the rolling bearing. However, since the bearing of this type is formed by deep-drawing a steel plate having an outer ring, accuracy cannot be obtained by the bearing alone, and regular dimensions and accuracy are obtained only after the bearing is press-fitted into the inner diameter surface of the housing or the like. On the other hand, it is difficult to mold resin molded products with high accuracy, so even if a resin molded product such as a pulley is simultaneously molded or press-fitted into the needle roller bearing, the proper outer ring dimensions and accuracy cannot be obtained. . For this reason, the tolerance of the inscribed circle diameter of the needle roller varies greatly, and the range of the gap between the needle roller and the shaft increases, which causes angular contact of the bearing and abnormal noise. Due to these problems, it is difficult to use the needle roller bearing.

An object of the present invention is to provide a needle roller bearing device incorporating a resin molded product, which can control the clearance between the needle roller and the shaft with high accuracy, and can achieve cost reduction and torque reduction. That is.

[0006]

A needle roller bearing device incorporating a resin molded product according to the present invention is a needle roller bearing in which a resin molded product is provided with a backup ring for fitting a bearing, and an outer ring is a deep drawing molded product. The backup ring is press-fitted.

[0007]

According to this structure, the accuracy of the outer ring of the needle roller bearing can be obtained by following the inner diameter surface of the backup ring in a state of being press-fitted into the backup ring. On the other hand, since the backup ring is a member having a simple shape that is a member different from the resin molded product, it is easy to process and the material can be freely selected, so that the inner diameter can be controlled with high accuracy. Therefore, by controlling the inner diameter tolerance of the backup ring, the tolerance width of the inscribed circle diameter of the needle roller can be reduced and the clearance between the shaft and the shaft can be accurately controlled. Further, since the outer ring uses a needle roller bearing made of a deep-drawing product, it can be manufactured at a lower cost than a ball bearing and has a lower torque than a slide bearing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In this needle roller bearing device incorporating a resin molded product, a ring-shaped resin molded product 1 is provided with a backup ring 2 for bearing fitting, and the needle roller bearing 3 is press-fitted into the backup ring 2. The needle roller bearing 3 is of a so-called shell type, has no inner ring, and has a cage composed of a needle roller 5 and a cage 6 inside an outer ring 4 made of a deep-drawn product such as a steel plate. The needle roller 7 is incorporated. The resin molded product 1 is a pulley, a gear, a toothed pulley, or the like, and is a wire pulley in the illustrated example. As the material of the resin molded product 1, for example, polyacetal resin is used.

The material of the backup ring 2 is preferably a steel material or an iron-based sintered alloy, which is the same material as the outer ring 4 of the needle roller bearing 3, and a copper-based or copper-iron-based sintered alloy or other metal materials. Can be used. The backup ring 2 has a wall thickness of, for example, 10 mm, and preferably 1.5 mm or more. The backup ring 2 is fixed to the resin molded product 1 by simultaneous molding (insert molding) or press fitting. In this way, the needle roller bearing 3 is press-fitted into the backup ring 2 to which the resin molded product 1 is fixed, as indicated by the arrow in FIG. It should be noted that it is preferable to provide an uneven portion such as a knurled portion for preventing rotation with respect to the resin molded product 1 and slipping-out on the outer diameter surface of the backup ring 2.

According to this structure, the outer ring 4 of the needle roller bearing 3 can be obtained by following the inner diameter surface of the backup ring 2 with accuracy while being pressed into the backup ring 2. on the other hand,
Since the backup ring 2 is a member having a simple shape made of an iron material or the like, it is easy to process and the inner diameter can be finished with high precision. Therefore, by controlling the inner diameter tolerance of the backup ring 2, it is possible to reduce the tolerance width of the inscribed circle diameter of the arrangement of the needle rollers 5 and accurately control the clearance between the backup ring 2 and the shaft 8. Therefore, it is possible to prevent angular runout and abnormal noise in the needle roller bearing 3.

When the material of the backup ring 2 is the same as that of the outer ring 4 of the needle roller bearing 3, the coefficient of thermal expansion is about the same, and therefore, the dimension due to the heat after the backup ring 2 and the outer ring 4 are assembled. The influence of the change, that is, the influence on the fitting can be reduced. Similarly, when the backup ring 2 is made of an iron-based sintered alloy, the thermal effect can be reduced. Moreover, since the shell-type needle roller bearing 3 and the backup ring 2 are used, it can be manufactured at a lower cost than a ball bearing and has a lower torque than a slide bearing.

[0012]

The needle roller bearing device with a resin molded product according to the present invention is provided with a resin molded product provided with a backup ring for bearing fitting, and a shell type needle roller bearing is press-fitted into the backup ring. Therefore, it is possible to reduce the tolerance width of the inscribed circle diameter of the needle roller to accurately control the gap between the needle roller and the shaft, and to reduce the torque and the cost.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory view of the assembling process.

[Explanation of symbols]

1 ... Resin molded product, 2 ... Backup ring, 3 ... Needle roller bearing, 4 ... Outer ring, 5 ... Needle roller, 8 ... Shaft

Claims (1)

[Claims] 1. A needle roller bearing device incorporating a resin molded product, wherein a resin-molded product is provided with a backup ring for fitting a bearing, and an outer ring is a deep-drawn molded product, and a needle roller bearing is press-fitted into said backup ring.