Bearing cage and method for manufacturing a bearing cage

Abstract

To provide a cage for a bearing which is manufactured by sheet-metal press work and a method of manufacturing a cage for a bearing that eliminate malfunctions caused burrs which occur after an inside-diameter cutting process is performed while keeping manufacturing cost from increasing.SOLUTION: A metallic cage for use with a rolling bearing has such a shape that a pair of large-diameter ring part and a small-diameter ring part 3 which are separated from each other in an axial direction are connected to each other by a plurality of column parts. The cage has an annular recess A recessed toward the large-diameter ring part at an end part of an axial end face 3A of the small-diameter ring part 3 at a radially inner side RI. A tip of a bur B of an internal peripheral face 3B of the small-diameter ring part 3 lies closer to the large-diameter ring part than to an axially outermost side E of the axial end face 3A. A portion of the annular recess A at a radially outer side RO has an inclination face C2 which ascends as it goes inward in the radial direction. An inclination angle of the inclination face C2 is equal to or larger than 10° and equal to or smaller than 20° with respect to a plane orthogonal to an axis of rotation O.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cage for tapered roller bearings, angular contact ball bearings, or cylindrical roller bearings manufactured by sheet metal pressing, and a method for manufacturing said bearing cage.

Background Art

[0002] There are bearing cages manufactured from a disk-shaped raw material (for example, the circular metal base plate 9 in Patent Document 1) through multi-stage pressing (see, for example, Patent Documents 1 and 2, etc.). Such a metal bearing cage has a shape in which a pair of a large-diameter ring portion and a small-diameter ring portion spaced apart in the axial direction are connected by a plurality of pillar portions.

[0003] In the manufacturing process of a cage for tapered roller bearings, angular contact ball bearings, or cylindrical roller bearings, there is an inner diameter punching step of punching and removing the bottom plate portion radially inward of the small-diameter ring portion, as shown in, for example, (d) of FIG. 3 and (e) of FIG. 5 of Patent Document 1.

Prior Art Literature

Patent Literature

[0004]

Patent Literature 1

Patent Literature 2

Summary of Invention

Problem to be Solved by the Invention

[0005] When the bottom plate portion of a cage for a tapered roller bearing, angular contact ball bearing, or cylindrical roller bearing is punched and removed, burrs are generated on the inner circumferential surface of the small-diameter ring portion from which the bottom plate portion has been punched, and the generated burrs protrude from the bottom surface (axial end surface) of the small-diameter ring portion. If burrs protrude from the bottom surface of the small-diameter ring portion, there is a risk of problems such as injury to workers when assembling the bearing, and falling off of the burrs and getting caught in the bearing during use of the bearing incorporating the cage.

[0006] To remove burrs protruding from the bottom surface of the holder, a surface treatment process such as shot blasting or a surface pressing process is required after press working, which increases the manufacturing cost. Furthermore, to perform punching in a way that prevents burrs from protruding from the bottom surface of the holder, fine blanking, which enables precise press working, is required. Fine blanking requires expensive dedicated machines equipped with high-precision dedicated molds and double-acting hydraulic systems, which increases the manufacturing cost. Depending on the shape of the product, fine blanking may not be possible.

[0007] The present invention aims to eliminate problems caused by burrs generated after the inner diameter punching process, while suppressing an increase in manufacturing costs, in a cage for a tapered roller bearing, an angular contact ball bearing, or a cylindrical roller bearing manufactured by sheet metal press working, and in a method for manufacturing the said bearing cage. [Means for solving the problem]

[0008] A bearing cage according to a first aspect of the present invention is a metal cage for use in a tapered roller bearing, an angular contact ball bearing, or a cylindrical roller bearing, and has a shape in which a pair of axially spaced large-diameter ring portions and small-diameter ring portions are connected by a plurality of columnar portions. The radially inward end of the axial end face of the small-diameter ring portion has an annular recess that is recessed toward the large-diameter ring portion. The radially outward portion of the annular recess has an inclined surface that rises as it extends radially inward, and the inclination angle of the inclined surface is 10 degrees or more and 20 degrees or less with respect to a plane perpendicular to the rotation axis of the bearing. The tip of the burr on the inner surface of the small-diameter ring portion is closer to the large-diameter ring portion than the outermost axial part of the axial end face.

[0009] This invention 2The method for manufacturing a bearing cage relating to this viewpoint is a method for manufacturing a metal cage used in tapered roller bearings, angular contact ball bearings, or cylindrical roller bearings. The cage has a shape in which a pair of axially spaced large-diameter ring portions and small-diameter ring portions are connected by a plurality of columnar portions. In the process of manufacturing the cage from a disc-shaped material through multi-stage press working, there is an inner diameter punching step in which the bottom plate portion on the radially inward side of the small-diameter ring portion is punched out and removed from the intermediate molded product after the drawing step. The upper surface of the radially inward end of the punching die used in the inner diameter punching step is an inclined surface that rises as it goes radially inward, and the inclination angle of the inclined surface is the bearings The angle is between 10 and 20 degrees with respect to a plane perpendicular to the axis of rotation. In the molded product after the inner diameter removal process, an annular recess is formed at the radially inward end of the axial end face of the small diameter ring portion, and the tip of the burr formed on the inner circumferential surface of the small diameter ring portion is positioned closer to the large diameter ring portion than the outermost axial part of the axial end face. [Effects of the Invention]

[0010] According to the bearing cage and the method for manufacturing the bearing cage of the present invention, the tip of the burr on the inner circumferential surface of the small-diameter ring portion of the cage for a tapered roller bearing, angular contact ball bearing, or cylindrical roller bearing, which is generated during the inner diameter removal process, is located closer to the large-diameter ring portion of the cage than the outermost axial direction of the axial end face of the small-diameter ring portion. Therefore, since the tip of the burr does not protrude beyond the bottom surface of the small-diameter ring portion of the cage, it is possible to avoid the burr being prone to falling off due to contact before bearing assembly. For example, the cages do not interfere with each other even when stacked, and the burr does not come into contact with other parts during transportation, etc.

[0011] Therefore, even without removing the burrs, problems such as workers being injured during bearing assembly and burrs falling off and getting caught in the bearing during use of the bearing with the cage incorporated can be suppressed. As a result, there is no need to perform surface treatments such as shot blasting or surface pressing processes to remove the burrs, and there is no need to perform fine blanking, so manufacturing costs do not increase.

[0012] Since the inclination angle of the inclined surface is 10 degrees or more with respect to a plane perpendicular to the rotation axis of the bearing, there is no risk of the tip of the burr protruding beyond the bottom surface of the small-diameter ring portion. Since the inclination angle of the inclined surface is 20 degrees or less with respect to a plane perpendicular to the rotation axis of the bearing, when the small-diameter ring portion that contacts the cutting edge of the punching die undergoes plastic deformation due to the pressure applied by the punching punch, and the shape of the punching die is transferred, the amount of plastic deformation is not so large that it causes warping or deformation of the retainer, thus preventing deterioration of the shape accuracy such as roundness of the retainer.

[0013] Furthermore, according to the bearing cage manufacturing method of the present invention, by simply changing the shape of the upper surface of the punching die in the inner diameter punching process, other mold components such as the punching punch can use conventional molds, and the inner diameter punching process remains a single process as before, thus suppressing an increase in manufacturing costs. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic longitudinal cross-sectional view of a tapered roller bearing cage, which is a bearing cage according to an embodiment of the present invention. [Figure 2] This is a longitudinal cross-sectional view showing an intermediate molded product after the drawing process. [Figure 3] This is a longitudinal cross-sectional view and a close-up view of a key part, showing an example of an intermediate molded product after the internal diameter removal process. [Figure 4] This is a schematic longitudinal cross-sectional view illustrating the mold used in the internal diameter punching process. [Figure 5] This is an enlarged view of the main part of Figure 4. [Figure 6] This is a longitudinal cross-sectional view and an enlarged view of a key part showing an example of an intermediate molded product after the inner diameter removal process when the bearing cage is an angular contact ball bearing cage. [Figure 7] This is a longitudinal cross-sectional view and an enlarged view of a key part showing an example of an intermediate molded product after the inner diameter removal process when the bearing cage is a cylindrical roller bearing cage. [Modes for carrying out the invention]

[0015] Next, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0016] In the present specification, in a state where the bearing retainer is assembled to a rolling bearing, a direction orthogonal to the direction of the rotation axis of the bearing (see reference symbol O in the drawings) is referred to as "radial direction" (see arrow R in the drawings). In the "radial direction", the direction away from the rotation axis is referred to as "radially outward" (see arrow RO in the drawings), and the direction approaching the rotation axis is referred to as "radially inward" (see arrow RI in the drawings). A direction parallel to the direction of the rotation axis of the bearing is referred to as "axial direction" (see arrow J in the drawings). "Circumferential direction" is defined with respect to the direction of the rotation axis.

[0017] <Bearing Retainer> A bearing retainer 1 according to an embodiment of the present invention shown in the schematic longitudinal sectional view of FIG. 1 is a metal tapered roller bearing retainer 1A, and steel plates such as SPCC (JIS standard: cold-rolled steel plate) and SPHC (JIS standard: hot-rolled steel plate) are used therefor. The tapered roller bearing retainer 1A has a shape in which a pair of a large-diameter ring portion 2 and a small-diameter ring portion 3 spaced apart in the axial direction J are connected by a plurality of pillar portions 4 equally arranged in the circumferential direction. Tapered rollers, which are rolling elements, are accommodated in pockets 5 between adjacent pillar portions 4, 4.

[0018] As shown in the enlarged view of a main part of the intermediate molded product Ip after the inner diameter punching step in FIG. 3, an end portion on the radially inward RI side of the axial end surface 3A of the small-diameter ring portion 3 is provided with an annular recess A recessed toward the large-diameter ring portion 2 (see FIG. 1). The tip of the burr B on the inner peripheral surface 3B of the small-diameter ring portion 3 is closer to the large-diameter ring portion 2 than the axially outermost portion E of the axial end surface 3A which is the bottom surface of the small-diameter ring portion 3. The plate thickness T is, for example, 2.0 mm or more and 3.5 mm or less.

[0019] A portion of the annular recess A located at radially outward RO has an inclined surface C2 that rises toward radially inward RI. An inclination angle β of the inclined surface C2 with respect to a plane orthogonal to the rotation axis O is 10 degrees or more and 20 degrees or less.

[0020] <Method for Manufacturing Bearing Retainer> A method for manufacturing a tapered roller bearing retainer 1A, which is the bearing retainer 1, is a method for manufacturing the retainer 1A by sheet metal press working, and includes a step of manufacturing the retainer 1A from a disk-shaped raw material through multi-stage press working.

[0021] The manufacturing method for the cage 1A for a tapered roller bearing includes a drawing process, a pocket hole punching process, an edge cutting process, and an inner diameter punching process. The drawing process involves forming an intermediate molded product Id shown in Figure 2 from a disc-shaped material by drawing. The pocket hole punching process involves punching out pocket holes 5 shown in Figure 1. The edge cutting process involves flattening the upper edge portion F shown in Figures 2 and 3 as shown in Figure 1. The inner diameter punching process involves removing the bottom plate portion H of the radially inward RI of the small diameter ring portion 3 by punching out the intermediate molded product Id after the drawing process shown in Figure 2, as shown in the intermediate molded product Ip shown in Figure 3.

[0022] (Details of the internal diameter removal process) Refer to the schematic longitudinal section view in Figure 4 and the enlarged view of the main part in Figure 5. For example, the inner diameter punching process is performed using a punching die D and a punching punch P, as well as a first guide ring G1 and a second guide ring G2, as shown in Figure 4. The second guide ring G2 has a guiding function when setting the intermediate molded product Id. The first guide ring G1 has the function of aligning the center position of the punching punch P and the intermediate molded product Id, and the function of removing the intermediate molded product Ip from the punching punch P after molding.

[0023] As shown in Figure 5, the upper surface of the radially inward RI-side end of the punching die D is an inclined surface C1 that rises as it approaches the radially inward RI, and the inclination angle α of the inclined surface C1 with respect to a plane perpendicular to the rotation axis O (see Figure 4) is set to 10 degrees or more and 20 degrees or less. If the inclination angle α is less than 10 degrees, the tip of the burr B may protrude beyond the bottom surface 3A of the small-diameter ring portion 3 shown in Figure 3. If the inclination angle α exceeds 20 degrees, as will be described later, when the small-diameter ring portion 3 that contacts the cutting edge of the punching die D undergoes plastic deformation due to the pressure applied by the punching punch P and the shape of the punching die D is transferred, the amount of plastic deformation may be too large, causing warping or deformation of the retainer 1, and the shape accuracy such as roundness of the retainer 1 is likely to deteriorate.

[0024] As shown in Figures 4 and 5, when the internal diameter punching process is performed using the punching die D and punching punch P, the small diameter ring portion 3 of the holder that contacts the cutting edge of the punching die D is plastically deformed by the pressure applied by the punching punch P, and the shape of the punching die D is transferred to the small diameter ring portion 3. Upon completion of the internal diameter punching process, an intermediate molded product Ip, shown in Figure 3, is obtained, which has an annular recess A. The inclined surface C2 of the intermediate molded product Ip is formed by the inclined surface C1 of the punching die D, and the inclination angle β of the inclined surface C2 corresponds to the inclination angle α of the inclined surface C1 of the punching die D.

[0025] <Another example of a bearing cage> The bearing cage 1 according to the embodiment of the present invention is not limited to a tapered roller bearing cage 1A, but can be applied to metal cages manufactured by sheet metal press working and subjected to an internal diameter punching process, such as an angular contact ball bearing cage 1B or a cylindrical roller bearing cage 1C.

[0026] An example of an intermediate molded product Ip after the inner diameter removal process when the bearing cage 1 is an angular contact ball bearing cage 1B is shown in the longitudinal cross-sectional view and the enlarged view of the main part in Figure 6. Similarly, an example of an intermediate molded product Ip after the inner diameter removal process when the bearing cage 1 is a cylindrical roller bearing cage 1C is shown in the longitudinal cross-sectional view and the enlarged view of the main part in Figure 7. In Figures 6 and 7, the same reference numerals as in Figures 1 and 3 indicate the same or corresponding parts or specifications.

[0027] The cage 1B for angular contact ball bearings in Figure 6 and the cage 1C for cylindrical roller bearings in Figure 7, like the cage 1A for tapered roller bearings in Figures 1 and 3, have an annular recess A at the radially inward RI end of the axial end face 3A of the small-diameter ring portion 3, which is recessed toward the large-diameter ring portion 2. The tip of the burr B on the inner circumferential surface 3B of the small-diameter ring portion 3 is closer to the large-diameter ring portion 2 than the outermost axial part E of the axial end face 3A, which is the bottom surface of the small-diameter ring portion 3. The plate thickness T is, for example, 2.0 mm or more and 3.5 mm or less.

[0028] The radially outward RO portion of the annular recess A has an inclined surface C2 that rises as it moves radially inward RI. The inclination angle β of the inclined surface C2 with respect to the plane perpendicular to the axis of rotation O is between 10 and 20 degrees.

[0029] <Effects and Effects> According to the bearing cage 1 and the manufacturing method for the bearing cage 1 according to an embodiment of the present invention, the tip of the burr B on the inner circumferential surface 3B of the small-diameter ring portion 3 of the cage 1, which is generated when the inner diameter removal process is performed, is closer to the large-diameter ring portion 2 of the cage 1 than the outermost axial part E of the axial end face 3A of the small-diameter ring portion 3. Therefore, since the tip of the burr B does not protrude beyond the bottom surface 3A of the small-diameter ring portion 3 of the cage 1, it is possible to avoid a situation where the burr B is easily detached by contact before bearing assembly. For example, even if the cages 1 are stacked, the cages 1 will not interfere with each other, and the burr B will not come into contact with other parts during transportation, etc.

[0030] Therefore, even without removing burr B, problems such as worker injury during bearing assembly and burr detachment and jamming into the bearing during use of the bearing with cage 1 incorporated can be suppressed. As a result, there is no need to perform surface treatments such as shot blasting or surface pressing processes to remove burr B, and there is no need to perform fine blanking, so manufacturing costs do not increase.

[0031] Furthermore, according to the manufacturing method of the bearing cage 1 of the present invention, by simply changing the shape of the upper surface of the punching die D in the inner diameter punching process, other mold components such as the punching punch P can use conventional molds, and the inner diameter punching process remains a single process as in the conventional method, thus suppressing an increase in manufacturing costs.

[0032] The embodiments described above are all illustrative and not limiting. Various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of Symbols]

[0033] 1 Bearing cage 1A Cage for tapered roller bearing 1B Cage for angular contact ball bearings 1C Cage for cylindrical roller bearings 2. Large diameter ring section 3. Small diameter ring section 3A Axial end face (bottom face) 3B Inner surface 4 Pillar part 5 pocket holes A. Annular recess B Bali C1,C2 Slope D punching die Outermost point in the E axis direction F Upper edge G1 First Guide Ring G2 Second Guide Ring H Bottom plate part Id Intermediate molded product after the drawing process Ip Intermediate molded product after the internal diameter removal process J-axis direction O Rotation axis P Punch R radial direction RI radially inward RO radially outward T plate thickness α,β Tilt angle

Claims

1. A metal cage used in tapered roller bearings, angular contact ball bearings, or cylindrical roller bearings, It has a shape in which a pair of large-diameter ring sections and small-diameter ring sections, spaced apart in the axial direction, are connected by multiple columnar sections. The radially inward end of the axial end face of the small-diameter ring portion has an annular recess that is recessed toward the large-diameter ring portion. The radially outward portion of the annular recess has an inclined surface that rises as it goes radially inward. The inclination angle of the inclined surface is 10 degrees or more and 20 degrees or less with respect to a plane perpendicular to the rotation axis of the bearing. The tip of the burr on the inner surface of the small-diameter ring portion is closer to the large-diameter ring portion than the outermost axial part of the axial end face. Bearing cage.

2. A method for manufacturing a metal cage used in tapered roller bearings, angular contact ball bearings, or cylindrical roller bearings, The retainer has a shape in which a pair of large-diameter ring sections and small-diameter ring sections, spaced apart in the axial direction, are connected by a plurality of columnar sections. The process of manufacturing the retainer from a disc-shaped material through multi-stage press processing includes an inner diameter punching step in which the bottom plate portion on the radially inward side of the small diameter ring portion is punched out and removed from the intermediate molded product after the drawing process. The upper surface of the radially inward end of the punching die used in the aforementioned inner diameter punching process is made into an inclined surface that rises as it goes radially inward. The inclination angle of the inclined surface is 10 degrees or more and 20 degrees or less with respect to a plane perpendicular to the rotation axis of the bearing. In the molded product after the inner diameter removal process, an annular recess is formed at the radially inward end of the axial end face of the small-diameter ring portion, which is recessed toward the large-diameter ring portion. The tip of the burr formed on the inner circumferential surface of the small-diameter ring portion is positioned closer to the large-diameter ring portion than the outermost axial part of the axial end face. A method for manufacturing a bearing cage.

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