Crown retainer for bearing

Abstract

[Problem] To provide a crown retainer for a bearing which can cope with high-speed rotation due to reduced weight, and with which positional deviation of a retaining part can be prevented and cost can be reduced. [Solution] A crown retainer (retainer 100) for a bearing according to the present invention retains rolling elements that roll between inner and outer rings of a bearing. The crown retainer for a bearing is characterized by comprising a metal annular part 110 centering around an axial center of the bearing, and a plurality of retaining parts 120 that are arranged in the circumferential direction of the annular part 110 and that have claws 122 for retaining the rolling elements, the annular part 110 having a front surface 112, an outer peripheral surface 114, and an inner peripheral surface 116 exposed between the retaining parts 120, and a back surface 118 of the annular part 110 being covered with a resin (back surface resin 130) integrally molded with the retaining parts 120, where the front surface is the claw 122-side surface of the annular part 110 and the back surface is the surface on the opposite side.

Description

Crown cage for bearings

[0001] The present invention relates to a crown type cage for a bearing that holds rolling elements that roll between inner and outer rings of the bearing.

[0002] Bearings generally use a bearing cage (hereafter referred to as cage). The cage holds rolling elements (balls or rollers) in each of several pockets, maintaining the spacing between the rolling elements and preventing the rolling elements from rubbing against each other. There are various types of cages used, one of which is the crown cage.

[0003] In the past, to save space, pressed cages made by stamping and forming metal material were often used for high-speed rotation bearings. However, pressed cages are heavy, resulting in high inertia during high-speed rotation. Therefore, in recent years, resin cages have been used in place of pressed cages, even for high-speed rotation.

[0004] For example, Patent Document 1 discloses "a crown-type cage comprising an annular main portion made of synthetic resin and a plurality of sets of pockets provided on one axial surface of the main portion, each pocket being formed integrally with the main portion and having a pair of elastic pieces spaced apart from each other in the circumferential direction, each of which holds a ball in a rollable manner between them." The crown-type cage in Patent Document 1 is characterized in that "a metal wire, which is an annular member having an elastic constant greater than that of the synthetic resin, is insert-molded around the entire circumference of the main portion, and at least the maximum diameter portion of the annular member is embedded in the main portion."

[0005] Japanese Patent Application No. 2023-131588

[0006] As described above, the use of a resin cage reduces the cage's weight and reduces inertia during high-speed rotation. However, resin cages are more prone to deflection than pressed cages. As a result, when centrifugal force is applied during high-speed rotation, the resin cage deforms toward the outer diameter, causing tension between the resin cage and the rolling elements (balls), resulting in an abnormal temperature rise and making the cage more susceptible to seizure.

[0007] Therefore, the inventor proposed "a crown-type cage having a metal annular portion centered on the axis of the bearing and a plurality of resin retaining portions arranged intermittently in the circumferential direction of the annular portion" in Patent Document 2. This configuration made it possible to achieve both the effect of suppressing deformation during high-speed rotation of the bearing and weight reduction.

[0008] Patent Document 2 proposes forming grooves in the annular portion by laser processing to improve adhesion between the resin holding portion and the annular portion in order to prevent misalignment of the discontinuously arranged holding portions. However, laser processing of the annular portion increases the processing time, so there is a demand for preventing misalignment without laser processing. Furthermore, when the discontinuously arranged resin holding portions are injection molded (the annular portions are insert molded), a gate must be formed in the mold for each holding portion (increasing the number of gates), which is an issue that increases costs.

[0009] In view of the above problems, the present invention aims to provide a crown type cage for a bearing that is lightweight and therefore capable of handling high-speed rotation, that prevents misalignment of the retaining portion, and that can also achieve cost reduction.

[0010] In order to solve the above problems, a typical configuration of a crown type cage for a bearing according to the present invention is a crown type cage for a bearing that holds rolling elements that roll between the inner and outer rings of the bearing, and includes a metal annular portion centered on the axis of the bearing, and a plurality of holding portions that are arranged circumferentially of the annular portion and have claws that hold the rolling elements, and when the surface of the annular portion on the claw side is called the front surface and the opposite surface is called the back surface, the front surface, outer peripheral surface and inner peripheral surface of the annular portion are exposed between the holding portions, and the back surface of the annular portion is covered with resin that is molded integrally with the holding portions.

[0011] According to the present invention, it is possible to provide a crown type cage for a bearing that is lighter in weight, can accommodate even higher speed rotation, and can achieve cost reduction.

[0012] 1 is a cross-sectional view of the bearing crown cage according to the present embodiment, taken from the front side; FIG. 2 is a cross-sectional view of the bearing crown cage according to the present embodiment, taken from the rear side;

[0013] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0014] Fig. 1 is an overall perspective view of a crown type bearing cage according to this embodiment, observed from the front side. Fig. 2 is an overall perspective view of the crown type bearing cage according to this embodiment, observed from the back side. In this embodiment, balls (not shown) are used as an example of rolling elements incorporated into the crown type bearing cage, but this is not limiting, and the present invention can also be applied using rollers as rolling elements.

[0015] The crown type cage for a bearing shown in Fig. 1 (hereinafter referred to as cage 100) holds rolling elements (not shown) that roll between the inner and outer rings of a bearing. The cage 100 is configured to include an annular portion 110 and a plurality of holding portions 120. The annular portion 110 is a metal member having an annular shape centered on the axis C of the bearing. For example, SPCC (cold-rolled steel plate) can be suitably used as the material for the annular portion 110, and the annular portion 110 can be formed by pressing the SPCC.

[0016] The plurality of retaining portions 120 are arranged in the circumferential direction of the annular portion 110. The plurality of retaining portions 120 are resin members made of resin such as nylon (polyamide synthetic resin) or ABS, and form pockets 124 with pairs of claws 122 that hold the rolling elements. Hereinafter, the surface of the annular portion 110 facing the claws 122 will be referred to as the front surface, and the opposite surface will be referred to as the back surface.

[0017] In this embodiment, a configuration in which eleven holding portions 120 are arranged in the circumferential direction of the annular portion 110 is illustrated, but the present invention is not limited to this. The number of annular portions 110 can be changed as appropriate according to the number of rolling elements of the bearing.

[0018] Figure 3 is a cross-sectional view taken along the line A-A in Figure 1. As shown in Figure 3, the cage 100 has a metal annular portion 110 insert-molded into a resin holding portion 120. As a result, in the cage 100, the multiple holding portions 120 are connected by the annular portions 110. Therefore, the cage can be made lighter than conventional cages that are molded entirely from resin, and can accommodate even higher speed rotation.

[0019] 1 , the annular portion 110 has a front surface 112, an outer peripheral surface 114, and an inner peripheral surface 116 exposed between the retaining portions 120. Meanwhile, the back surface 118 of the annular portion 110 is covered with a resin (hereinafter referred to as a back surface resin 130) that is molded integrally with the retaining portions 120 (see also FIGS. 2 and 3 ). The back surface resin 130 is injection molded (the annular portion 110 is insert molded) integrally with the resin that constitutes the retaining portions 120.

[0020] That is, on the back surface 118 of the annular portion 110 of the cage 100 of this embodiment, the multiple holding portions 120 are connected by the back surface resin 130. This makes it possible to preferably prevent the holding portions 120 from shifting position on the annular portion 110, compared to when the multiple holding portions 120 are arranged discontinuously.

[0021] Furthermore, because the front surface 112, outer peripheral surface 114, and inner peripheral surface 116 of the annular portion 110 are exposed, these three surfaces can be placed against a mold for positioning during insert molding. Furthermore, as illustrated in FIG. 2 , a back surface resin 130 covering the back surface 118 of the annular portion 110 of the cage 100 has multiple holes 132 formed therein. These holes are marks left by positioning pins that pressed the annular portion 110 against a mold for positioning during insert molding. Therefore, strictly speaking, the entire back surface 118 of the annular portion 110 is not covered by the back surface resin 130. However, because the area of ​​the holes 132 is very small, the back surface 118 of the annular portion 110 illustrated in FIG. 2 can be considered to be covered by the back surface resin 130.

[0022] Strictly speaking, the outer peripheral surface 114 and inner peripheral surface 116 of the annular portion 110 are exposed on the claw 122 side, but a portion on the back surface 118 side is buried in the back surface resin 130. However, what is important in the present invention is to position the outer peripheral surface 114 and inner peripheral surface 116 by contacting them with the mold, and it is not necessary for all of these surfaces to be exposed. The object of the present invention can be achieved as long as even a portion on the front surface 112 side is exposed.

[0023] Furthermore, with the cage 100 of this embodiment, it is possible to reduce the amount of resin connecting the holding portions 120 to each other near the claws 122, compared to conventional cages that are molded entirely from resin. This allows the weight of the holding portions 120 to be reduced, and therefore the centrifugal force acting on the claws 122 can be reduced.

[0024] Furthermore, as in this embodiment, the multiple holding portions 120 are connected by the back surface resin 130 on the back surface 118 of the annular portion 110, so that resin can be poured into the multiple holding portions 120 from a common gate. This reduces the number of gates in the mold, contributing to lower costs.

[0025] The present invention can be used as a crown type cage for a bearing that holds rolling elements that roll between the inner and outer rings of the bearing.

[0026] 100... retainer, 110... annular portion, 112... front surface, 114... outer peripheral surface, 116... inner peripheral surface, 118... rear surface, 120... retaining portion, 122... claws, 124... pocket, 130... rear surface resin, 132... hole

Claims

1. A crown-type cage for a bearing that holds rolling elements that roll between an inner and outer ring of the bearing, comprising: a metallic annular portion centered on the axis of the bearing; and a plurality of retaining portions arranged circumferentially of the annular portion and having pawls that hold the rolling elements, wherein the surface of the annular portion facing the pawls is called the front surface and the opposite surface is called the back surface, and the front surface, outer peripheral surface and inner peripheral surface of the annular portion are exposed between the retaining portions, and the back surface of the annular portion is covered with resin that is molded integrally with the retaining portions.

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