Crown shaped retainer for bearing

Abstract

To provide a crown shaped retainer for a bearing which can achieve deformation inhibition effect during high speed rotation of the bearing and reduction of the weight.SOLUTION: A structure of a crown type retainer for a bearing (a retainer 100) according to the invention retains rolling elements which roll between inner and outer rings of the bearing. The crown type retainer includes: a metallic annular part 110 centered on an axis of the bearing; and a plurality of resin retaining parts 120 which are intermittently arranged in a circumferential direction of the annular part 110. The retaining part 120 has: a pair of claws 122 forming a pocket 126 for retaining the rolling element; and a base part 124 in which the annular part 110 is insert-molded and which connects the pair of claws 122.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Bearings generally use a bearing cage (hereafter referred to as a cage). The cage holds the 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, in order 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, and so the inertia during high-speed rotation increases. For this reason, in recent years, resin cages made of resin are sometimes used instead of pressed cages, even for high-speed rotation.

[0004] By using a resin cage as described above, the weight of the cage can be reduced, and the inertia during high-speed rotation can be reduced. However, a resin cage has a lower Young's modulus than a pressed cage and is more likely to bend. For this reason, a resin cage tends to have lower rigidity than a pressed cage. In particular, because the resin material is temperature-dependent, the decrease in rigidity tends to be more pronounced as the temperature rises during rotation.

[0005] 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 integrally formed with the main portion and holding one ball between a pair of elastic pieces spaced apart from each other in the circumferential direction so that the balls can roll freely."

[10] The crown-type cage of 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 over the entire circumference of the main portion, and at least the maximum diameter portion of the annular member is embedded in the main portion." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-298164 A Summary of the Invention [Problem to be solved by the invention]

[0007] According to Patent Document 1, "By making the annular member into an annular metal wire, the amount of metal required to suppress deformation of the pair of elastic pieces (claw-shaped parts) that form the main part and pocket of the synthetic resin crown-type cage is the minimum required, making it possible to realize an inexpensive and lightweight cage." However, it is considered that a thin linear part such as a metal wire does not have a significant effect of suppressing deformation during high-speed rotation of the bearing. In the configuration of Patent Document 1, it is considered that the effect of suppressing deformation of the bearing can be increased by making the metal wire thicker, but there is a disadvantage in that the thickness of the pocket bottom becomes thicker.

[0008] In view of these problems, the present invention aims to provide a crown-type cage for a bearing that enables the width of the cage to be narrowed while simultaneously suppressing deformation during high-speed rotation of the bearing and reducing weight. [Means for solving the problem]

[0009] 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 a bearing, and includes 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, and is characterized in that the retaining portion has a pair of claws that form pockets that hold the rolling elements, and a base portion in which the annular portion is insert molded and that connects the pair of claws.

[0010] The annular portion may be laser-machined on the nail side or on the back surface. Effect of the Invention

[0011] According to the present invention, it is possible to provide a crown type cage for a bearing that is capable of suppressing deformation during high speed rotation of the bearing while also being lightweight. [Brief description of the drawings]

[0012] [Figure 1] 1 is an overall perspective view of a crown type cage for a bearing according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a perspective view illustrating a circular portion and a holding portion. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] FIG. 4 is a schematic cross-sectional view of a circular ring portion. [Diagram 5] 2 is a diagram for explaining a CAE analysis result of the cage of the embodiment shown in FIG. 1. FIG. [Figure 6] FIG. 13 is a diagram illustrating an example of the relationship between laser processing depth and adhesion rate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0014] Fig. 1 is an overall perspective view of a crown type cage for bearings (hereinafter referred to as cage 100) according to this embodiment. Fig. 2 is a perspective view illustrating an annular portion 110 and a retaining portion 120. Fig. 2(a) is a perspective view of the cage 100 with one retaining portion 120 omitted, and Fig. 2(b) is a perspective view of the retaining portion 120. Fig. 3 is a cross-sectional view taken along line AA in Fig. 1.

[0015] In this embodiment, balls (not shown) are used as an example of the rolling elements to be incorporated into the cage 100, but this is not limited thereto, and the present invention can also be applied using rollers as the rolling elements.

[0016] 1 holds rolling elements (not shown) that roll between an inner and outer ring of a bearing. The cage 100 includes 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. As a material for the annular portion 110, for example, SPCC (cold rolled steel plate) can be suitably used, and the annular portion 110 can be formed by pressing the SPCC.

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

[0018] The retaining portion 120 is a resin member made of resin such as nylon (polyamide synthetic resin) or ABS, and has a pair of claws 122 and a base 124 as shown in Fig. 2(b). The pair of claws 122 are connected by the base 124 to form a pocket 126 that retains the rolling element.

[0019] As shown in Fig. 1 and Fig. 3, a feature of the retainer 100 of this embodiment is that a metal annular portion 110 is insert-molded into a base portion 124 of a resin retaining portion 120. As a result, in the retainer 100, a plurality of retaining portions 120 are connected by the annular portions 110. In Fig. 2(b), since the annular portions 110 are not shown, a hole 128 is shown in the base portion 124 for convenience. However, it should be noted that the annular portions 110 are insert-molded into the retaining portions 120, and the annular portions 110 are not inserted into holes 128 that have been molded in advance.

[0020] According to the above configuration, the metallic annular portion 110 is insert molded into the base portion 124 of the retaining portion 120, thereby improving the rigidity of the base portion 124 and therefore the retainer 100. This makes it possible to suppress deformation of the retainer 100 during high-speed rotation of the bearing and to effectively prevent wear caused by contact with the rolling elements.

[0021] Furthermore, in the cage 100 of this embodiment, the multiple holding portions 120 are intermittently arranged on the annular portion 110. This allows for a reduction in weight compared to conventional cages in which the claws 122 of adjacent holding portions 120 are continuous with each other. Therefore, the cage 100 of this embodiment can achieve both the effect of suppressing deformation during high-speed rotation of the bearing and a reduction in weight.

[0022] 2(a), laser processing may be performed on the front surface 112a, which is the surface of the ring portion 110 facing the claw 122, and on the back surface 112b, which is the opposite surface. This increases the contact area between the front surface 112a and back surface 112b of the ring portion 110 and the inner surface of the hole 128 of the base portion 124. Therefore, the inner surface of the base portion 124 is engaged with the front surface 112a and back surface 112b of the ring portion 110, and the adhesion between the ring portion 110 and the base portion 124 can be improved.

[0023] The shape of the laser processing may be a linear groove extending in the circumferential direction or a linear groove extending in a direction intersecting the circumferential direction, or a grid-like (vertical and horizontal) groove or a twill (knurled) groove that is a combination of these linear grooves.

[0024] Fig. 4 is a schematic cross-sectional view of the annular portion 110, illustrating a cross-section of the front surface 112a of the front surface 112a and the back surface 112b of the annular portion 110. When the laser processing is performed, a groove 150 is formed in the front surface 112a of the annular portion 110, as shown in Fig. 4. When the annular portion 110 having the groove thus formed is insert-molded into the resin-made retaining portion 120 (strictly speaking, the base portion 124), the resin that has entered the groove 150 has a shape that is a transfer of the shape of the groove 150.

[0025] 4, in particular, groove 150 is inclined in the depth direction with respect to surface 112a of annular portion 110. As a result, when a force is applied to base 124 in a direction that peels it off from surface 112a of annular portion 110, base 124 is locked in groove 150. This improves the adhesion between base 124 of holder 120 and groove 150.

[0026] In the laser processing used to form groove 150 in this embodiment, the output of the laser can be varied to intentionally change the groove width. By increasing the output of the laser when forming groove 150, it is possible to melt and evaporate a greater amount of deeper positions on front surface 112a and back surface 112b of annular portion 110, and it is possible to make groove width W2 at deeper positions wider than groove width W1 at shallower positions as shown in FIG. 4.

[0027] According to this configuration, the base 124 of the holding part 120 has a shape of the groove 150 transferred thereto, and has a portion where the deeper portion of the groove 150 is wider than the shallower portion. Therefore, the resin of the base 124 that has entered the inside of the groove 150 functions as a wedge (anchor effect), making it difficult for the base 124 to peel off from the groove 150. Therefore, the adhesion between the base 124 and the groove 150 can be further improved.

[0028] Fig. 5 is a diagram illustrating the results of CAE analysis of the cage 100 of the present embodiment shown in Fig. 1. In the graph shown in Fig. 5(a), the horizontal axis is the inclination angle θ of the groove 150 as shown in Fig. 5(b). The vertical axis is the adhesion force between the inner surface of the base 124 of the retaining part 120 and the surface 112a of the annular part 110. The adhesion force on the vertical axis is a standardized value, with the adhesion force being 1 when the angle θ is 0°.

[0029] 5, the adhesion increases as the inclination angle θ of the groove 150 increases. Therefore, it can be understood that inclining the groove 150 is effective in improving the adhesion between the inner surface of the base portion 124 of the cage 120 and the annular portion 110.

[0030] Fig. 6 is a diagram illustrating the relationship between the laser processing depth and the adhesion rate. Fig. 6 illustrates the laser processing depth as the depth d (see Fig. 4) of the groove 150, and shows the change in the adhesion rate between the inner surface of the base 124 of the holding part 120 and the surface 112a of the annular part 110 when the laser processing depth is changed.

[0031] As shown in Fig. 6, when the laser processing depth is 0 µm, i.e., when no laser processing is performed, the adhesion rate is 0%, and as the laser processing depth increases, the adhesion rate increases. When the laser processing depth exceeds about 20 µm, the adhesion rate becomes 100%. From this, it can be understood that a high adhesion rate can be ensured between the inner surface of the base 124 of the holding part 120 and the surface 112a of the annular part 110 by setting the laser processing depth, i.e., the depth of the groove 150, to 20 µm or more. [Industrial Applicability]

[0032] The present invention can be utilized as a crown type cage for a bearing that holds rolling elements that roll between the inner and outer rings of the bearing. [Explanation of symbols]

[0033] 100: retainer, 110: ring portion, 120: retaining portion, 122: claws, 124: base portion, 126: pocket, 128: hole, C: shaft center

Claims

1. A crown-type cage for a bearing that holds rolling elements that roll between an inner ring and an outer ring of the bearing, a metal annular portion centered on the axis of the bearing; A plurality of resin holding portions arranged intermittently in a circumferential direction of the annular portion; Including, The holding portion is A pair of claws forming a pocket for holding the rolling element; a base portion in which the annular portion is insert-molded and which connects the pair of claws; A crown cage for a bearing, comprising:

2. 2. The cage for bearings according to claim 1, wherein the annular portion has a surface on the claw side or a back surface thereof that is laser machined.

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