Rolling bearing

Abstract

To provide a rolling bearing provided with a waveform retainer, and capable of suppressing sliding wear to the maximum, attaining high speed rotation and long life, and reducing temperature rise.SOLUTION: The rolling bearing includes: a bearing ring having an inner ring 2 and an outer ring 3; a plurality of balls 4 interposed between the inner ring 2 and the outer ring 3; and a waveform retainer 5 retaining the balls 4. In the waveform retainer 5, a pocket 8 for holding each ball 4 is formed, and a flange part 9 for guiding the bearing ring is provided on an inner diameter edge of the waveform retainer 5. The waveform retainer 9 is a waveform retainer in which two annular retaining plates having semi-cylindrical bulging portions disposed at a predetermined interval along a circumferential direction are combined in an axial direction, and in a state where the two annular retaining plates are combined, the semi-cylindrical bulging portions face each other to form the pocket 8 forming a cylindrical surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rolling bearing, and to a technique applied to, for example, servo motors, generators, automobiles, etc. [Background technology]

[0002] Deep groove ball bearings with steel wave-shaped cages can be mass-produced by pressing, so they are less expensive than deep groove ball bearings with cages made of injection-molded nylon or machined phenol, and are used in general industry, automobiles, etc. However, steel sheet corrugated cages are limited to shapes that can only be produced by pressing, and wear between the rolling elements and the cage pockets is unavoidable. This wear causes the bearings to heat up significantly, shortens their service life, and makes high-speed rotation difficult.

[0003] In steel plate corrugated cages, wear occurs on the pocket guide surfaces that come into contact with the rolling elements, and metal wear powder from the cage gets mixed into the grease, further worsening the lubrication condition and shortening the lubrication life of the grease. In conventional technology, in order to suppress wear on the guide surfaces of the pockets that hold the rolling elements (balls), a coating such as a resin coating or a trivalent chromium chromate is formed on the inner surface of the pockets that serve as the rolling element guide surfaces (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-172749 A [Patent Document 2] JP 2007-24295 A [Patent Document 3] JP 2009-150256 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional technology is effective in reducing pocket wear and maintaining the grease lubrication life. However, due to the rolling element guide system of the corrugated cage 50 as shown in Figure 9, the cage pocket 51 and the rolling element 4 are always in contact with each other as shown in Figure 10, which causes sliding wear between the cage pocket 51 and the rolling element 4. After a certain period of bearing rotation, the sliding wear may cause abnormalities in the surface layer of the resin coating film, surface compound, etc. on the inner surface of the pocket.

[0006] An object of the present invention is to provide a rolling bearing equipped with a wave cage, which minimizes sliding wear, achieves high speed rotation, has a long life, and reduces temperature rise. [Means for solving the problem]

[0007] The rolling bearing of the present invention is a rolling bearing including a raceway including an inner ring and an outer ring, a plurality of balls interposed between the inner ring and the outer ring, and a corrugated cage that holds the balls, The waveform cage has pockets formed therein for holding the balls, and is provided with a raceway-guided flange portion on the inner or outer edge of the waveform cage. The "raceway-guided" means that the waveform cage is guided against the outer circumferential surface of the inner ring or the inner circumferential surface of the outer ring in contact with or with a small radial gap between them. "The waveform cage is provided with a raceway-guided flange portion on the inner edge" means an inner ring guide in which the flange portion is guided against the outer circumferential surface of the inner ring. "The waveform cage is provided with a raceway-guided flange portion on the outer edge" means an outer ring guide in which the flange portion is guided against the inner circumferential surface of the outer ring.

[0008] According to this configuration, the corrugated cage is formed with pockets for holding the balls, and has a flange portion for guiding the raceways on the inner or outer edge of the corrugated cage. Therefore, the following advantages are achieved compared to conventional rolling element guided corrugated cages. -Reduces wear inside the pocket. - Sliding wear caused by the guide can be reduced. Increased freedom in designing the cage band width. Lubricant adhering to the balls does not accumulate in the pockets but can pass more easily between the pockets and the balls, reducing bearing temperature rise, leading to faster rotation and longer life.

[0009] The pockets may be formed on a cylindrical surface. In this case, the lubricant inside the pockets and the lubricant adhering to the balls can more easily pass between the pockets and the balls. In other words, the cylindrical pockets prevent the lubricant from accumulating in the pockets, improving the flowability of the lubricant.

[0010] In the case of an inner ring guide having the flange portion on the inner diameter edge of the corrugated cage, the following formula may be satisfied. φSd = φD × (1.01 to 1.02) φHdi = φdi + (0.2 to 1.0) φdo-0.1≧φHdo≧φHdi+(Cr×2÷9÷t) Ra=1.0 or less φSd: Pocket diameter φD: ball diameter φHdi: Inner diameter of flange φdi: Inner ring outer diameter φdo: Outer ring inner diameter φHdo: Outer diameter of the wave holder Cr: Basic dynamic load rating (unit: kN) t: thickness of the corrugated holder (unit: mm) Ra: Roughness of the guideway surface of the flange (arithmetic mean roughness: unit μm)

[0011] By using such an inner ring guide type wavy cage, sliding wear can be minimized, and a rolling bearing can be realized that can achieve high speed rotation, a long life, and small temperature rise. If the pocket diameter φSd is less than 1.01φD, the pocket clearance between the pocket and the balls may become too small, which may increase the sliding wear between the pocket and the balls.If the pocket diameter φSd is more than 1.02φD, the axial runout of the cage may become larger than desired.

[0012] If the inner diameter φHdi of the flange is less than 0.2φdi, the sliding wear between the flange and the outer diameter of the inner ring may become excessively large. If the inner diameter φHdi of the flange exceeds 1.0φdi, the radial runout of the cage may become larger than desired. If the outer diameter φHdo of the waveform cage is less than φHdi+(Cr×2÷9÷t), the rigidity of the waveform cage itself may be a problem. If the outer diameter φHdo of the waveform cage exceeds φdo-0.1, the radial clearance between the inner diameter of the outer ring and the waveform cage may not be secured. If the guide surface roughness Ra of the flange portion exceeds 1.0 μm, there is a risk of excessive sliding wear between the flange portion and the outer diameter of the inner ring.

[0013] The wavy cage may be a wavy cage formed by combining in the axial direction two annular retaining plates having semi-cylindrical bulges arranged at a predetermined interval along the circumferential direction, and the pockets forming the cylindrical surface may be formed by opposing the semi-cylindrical bulges when the two annular retaining plates are combined. In this case, for example, a wavy cage in which pockets forming a cylindrical surface are formed can be easily produced by pressing or the like.

[0014] In the case of an outer ring guide having the flange portion on the outer diameter edge of the corrugated cage, the following formula may be satisfied. φSd = φD × (1.01 to 1.02) φHdo = φdo - (0.2 to 1.0) φdo+0.1≧φHdi≧φHdo-(Cr×2÷9÷t) Ra=1.0 or less

[0015] φSd: Pocket diameter φD: ball diameter φHdo: Outer diameter of flange φdo: Outer ring inner diameter φHdi: Inner diameter of the wave holder Cr: Basic dynamic load rating (unit: kN) t: thickness of the corrugated holder (unit: mm) Ra: Roughness of the guideway surface of the flange (arithmetic mean roughness: unit μm) By using such an outer ring guide type wavy cage, sliding wear can be minimized, making it possible to realize a rolling bearing that can achieve high speed rotation, a long life, and small temperature rise. Effect of the Invention

[0016] The corrugated cage in the rolling bearing of the present invention has pockets for holding the balls, and is provided with a flange portion for guiding the raceways on the inner or outer edge of the corrugated cage. As a result, in the rolling bearing equipped with the corrugated cage, sliding wear is minimized, and high speed rotation, long life and small temperature rise can be achieved. [Brief description of the drawings]

[0017] [Figure 1] 1 is a vertical sectional view of a rolling bearing according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a wave cage of the rolling bearing. [Diagram 3] 3 is a cross-sectional view of the waveform cage of FIG. 2 taken along plane III. [Figure 4] FIG. 4 is a diagram showing parameters of the rolling bearing. [Figure 5A] FIG. 2 is a diagram conceptually explaining sliding wear of a rolling element guide; [Figure 5B] 4 is a diagram conceptually explaining the reduction in sliding wear of the rolling bearing. FIG. [Figure 6] 10A and 10B are diagrams for explaining the relative speeds of the rolling elements and the cage in each case of a raceway guide. [Figure 7A] 11A and 11B are diagrams illustrating the fluidity of grease in a spherical pocket. [Figure 7B] 11A and 11B are diagrams illustrating the fluidity of grease in a cylindrical pocket. [Figure 8] FIG. 6 is a diagram showing parameters of a rolling bearing according to a second embodiment of the present invention. [Figure 9] FIG. 1 is a perspective view of a conventional wave cage. [Figure 10] 10 is a cross-sectional view of the waveform cage of FIG. 9 taken along an X plane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [First embodiment] A rolling bearing according to an embodiment of the present invention will be described with reference to Figures 1 to 7B. The deep groove ball bearing, which is the rolling bearing according to the embodiment, is used in, for example, servo motors, generators, automobiles, etc. However, the deep groove ball bearing can also be used in applications other than those mentioned above.

[0019] <General structure of rolling bearing> As shown in FIG. 1, a deep groove ball bearing 1 includes an inner ring 2, an outer ring 3, balls 4 as rolling elements, and a corrugated cage 5 that holds the balls 4. A number of balls 4 are interposed between the raceways 2a, 3a of the inner and outer rings 2, 3 and are held at regular intervals in the circumferential direction by the cage 5. A lubricant such as grease is sealed in the bearing space between the inner and outer rings 2, 3. The inner and outer rings 2, 3 and the balls 4 are made of, for example, high carbon chromium bearing steel such as SUJ2 or martensitic stainless steel. However, the material is not limited to these steels. A seal member (not shown) that seals the bearing space may be attached to the outer ring 3.

[0020] In this specification, a rolling bearing or a deep groove ball bearing may simply be referred to as a "bearing." A wave cage may simply be referred to as a "cage." In the following description, the direction of the bearing center axis AX is referred to as the "axial direction," the direction perpendicular to the bearing center axis AX is referred to as the "radial direction," and the circumferential direction around the bearing center axis AX is referred to as the "circumferential direction." Additionally, the side toward the bearing center axis AX is referred to as the "inner diameter side," and the side away from the bearing center axis AX is referred to as the "outer diameter side."

[0021] <Waveform holder> As shown in Figure 2, the corrugated cage 5 has pockets 8 formed on the cylindrical surface for holding each ball. The corrugated cage 5 is a corrugated cage in which two annular retaining plates 5a, 5a are assembled in the axial direction, each plate having semi-cylindrical bulges 6 arranged at a predetermined interval along the circumferential direction. Each annular retaining plate 5a has semi-cylindrical bulges 6 arranged along the circumferential direction, and a flat portion 7 connecting adjacent semi-cylindrical bulges 6 in the circumferential direction.

[0022] When the annular retaining plates 5a, 5a are assembled, the flat portions 7 are overlapped, and these flat portions 7, 7 are connected via rivets or engagement claws (not shown). When the two annular retaining plates 5a, 5a are assembled, the semi-cylindrical bulges 6 face each other to form pockets 8 forming the cylindrical surface. Each pocket 8 holds a ball 4 (FIG. 1) as a rolling element. Each annular retaining plate 5a is, for example, a pressed product of a cold-rolled steel strip. The thickness of this corrugated cage 5 is formed to a constant thickness. The inner edge of the corrugated cage 5 includes an inner edge 6a of each semi-cylindrical bulge 6 and an inner edge 7a of each flat portion 7. The outer edge of the corrugated cage 5 includes an outer edge 6b of each semi-cylindrical bulge 6 and an outer edge 7b of each flat portion 7.

[0023] <Flange part> As shown in FIG. 3, the flange portion 9 guided by the raceway ring is provided on the edge portion 6a (FIG. 2) of the inner diameter side of each of the semi-cylindrical bulging portions 6 among the inner diameter edges of the corrugated cage 5. As shown in FIG. 2, the flange portion 9 extends in an arc shape so as to protrude a predetermined length from the inner diameter edge, which is the edge portion on the inner diameter side of each of the semi-cylindrical bulging portions 6, toward the axial outside of each of the pockets 8. In this example, the flange portion 9 is provided only on the semi-cylindrical bulging portions 6 and not on the flat portion 7, but it is also possible to form the flange portion 9 connected to the semi-cylindrical bulging portions 6 and the flat portion 7. In other words, the flange portion 9 guided by the inner ring may be provided on the edge portion 6a on the inner diameter side of each of the semi-cylindrical bulging portions 6 and the edge portion 7a on the inner diameter side of each of the flat portions 7. As shown in FIG. 3, the flange portion 9 is integrally formed with the semi-cylindrical bulging portions 6 and is formed to the same thickness t as the semi-cylindrical bulging portions 6.

[0024] <parameters> In the case of an inner ring guide having the flange portion 9 on the inner diameter edge of the corrugated cage 5 as shown in FIG. 4, all of the following formulas (1) to (4) are satisfied. φSd=φD×(1.01~1.02) …Equation (1) φHdi=φdi+(0.2~1.0) …Equation (2) φdo-0.1≧φHdo≧φHdi+(Cr×2÷9÷t) …Equation (3) Ra=1.0 or less...Equation (4) The above formula (1) means that the pocket diameter φSd is in the range of 1.01 times or more and 1.02 times or less the diameter φD of the ball 4. The formula (2) means that the inner diameter φHdi of the flange portion 9 is in the range of φdi+0.2 or more and φdi+1.0 or less.

[0025] All parameters are in mm unless otherwise specified. φSd: Pocket diameter φD: ball diameter φHdi: Inner diameter of flange φdi: Inner ring outer diameter φdo: Outer ring inner diameter φHdo: Outer diameter of the wave holder Cr: Basic dynamic load rating (unit: kN) t: thickness of corrugated cage Ra: Roughness of the guideway surface of the flange (arithmetic mean roughness: unit μm)

[0026] <Action and effect> In the deep groove ball bearing 1 of Fig. 1 described above, the pocket 8 is formed on a cylindrical surface, and a flange portion 9 is provided on the inner diameter edge of the cage 5. This allows for raceway ring guidance of the corrugated cage 5, and avoids sliding wear between the inside of the cage pocket and the rolling elements, which occurs with conventional rolling element guidance. 1.<Reducing sliding wear with raceway guideways> When the inner ring rotates and the outer ring is stationary, which is the normal use of bearings, in a cage with rolling element guide, as shown in Figure 5A, the cage 50 generates sliding wear with the rolling elements located in the load zone of the bearing on the side of the pocket surface in the direction of rotation, as shown in Figure 5A. On the other hand, the cage 5 with raceway (inner ring) guide also generates sliding wear with the raceway guide surface, as shown in Figure 5B.

[0027] However, as shown in Figure 6, the relative speed of the rolling elements to the cage is lower with the raceway guide than with the rolling element guide, and the cage experiences less sliding wear with the raceway guide surface compared to the sliding wear with the rolling elements. In Figure 6, the relative speed of the rolling elements to the cage in the case of the rolling element guide is expressed as Vb, and the relative speed of the rolling elements to the cage in the case of the raceway guide is expressed as Vi-Vr. ∵Vb=Vr Therefore, the sliding relative velocity of the raceway guide is less than the sliding relative velocity of the rolling element guide.

[0028] 2. <Grease fluidity, etc.> By changing the pockets of the cage from the spherical surface shown in Fig. 7A to the cylindrical surface shown in Fig. 7B, the grease G inside the pockets and the grease G adhering to the balls 4 can pass more easily between the pockets 8 and the balls 4. In other words, the cylindrical surface of the pockets 8 prevents the grease G from accumulating in the pockets 8, improving the fluidity. As a result, the deep groove ball bearing of this embodiment experiences less temperature rise, maintains grease lubrication, reduces wear between the pockets 8 and the balls 4, and enables higher speed rotation.

[0029] According to the deep groove ball bearing 1 in Fig. 1 explained above, the pocket 8 of the waveform cage 5 has a cylindrical surface, and the flange portion 9 guided by the raceway ring is provided on the inner diameter edge of the waveform cage 5. Therefore, the following effects are achieved compared to the conventional rolling element guided waveform cage. -Reduces wear inside the pocket. - Sliding wear caused by the guide can be reduced. Increased freedom in designing the cage band width. The lubricant adhering to the balls 4 does not accumulate in the pockets 8 but passes more easily between the pockets 8 and the balls 4, reducing the temperature rise of the bearing, leading to faster rotation and longer life.

[0030] 4, if the pocket diameter φSd is less than 1.01φD, the pocket clearance between the pocket 8 and the balls 4 becomes excessively small, which may increase the sliding wear between the pocket 8 and the balls 4. If the pocket diameter φSd exceeds 1.02φD, the axial runout of the cage 5 may become larger than desired.

[0031] If the inner diameter φHdi of the flange portion 9 is less than 0.2φdi, the sliding wear between the flange portion 9 and the outer diameter of the inner ring may become excessively large. If the inner diameter φHdi of the flange portion 9 exceeds 1.0φdi, the radial runout of the cage 5 may become larger than desired. If the outer diameter φHdo of the waveform cage 5 is less than φHdi+(Cr×2÷9÷t), the rigidity of the waveform cage itself may be a problem. If the outer diameter φHdo of the waveform cage 5 exceeds φdo-0.1, the radial clearance between the inner diameter of the outer ring and the waveform cage 5 may not be secured. If the guide surface roughness Ra of the flange portion 9 exceeds 1.0 μm, there is a risk that the sliding wear between the flange portion 9 and the outer diameter of the inner ring will become excessively large.

[0032] <Other embodiments> In the following description, parts corresponding to matters previously described in each embodiment are given the same reference numerals, and duplicated description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as the previously described embodiment unless otherwise specified. The same configuration has the same action and effect. It is possible to combine not only the parts specifically described in each embodiment, but also partially combine embodiments together, provided that there is no particular problem with the combination.

[0033] [Second embodiment: outer ring guide] As shown in FIG. 8, the outer diameter edge of the corrugated cage 5A may be provided with a flange portion 9 on the outer diameter side edge 6b of each semi-cylindrical bulging portion 6 to be an outer ring guide. The flange portion 9 extends in an arc shape so as to protrude a predetermined length from the outer diameter edge, which is the outer diameter side edge 6b of each semi-cylindrical bulging portion 6, toward the axial outside of each pocket 8. In this example, the flange portion 9 is provided only on the semi-cylindrical bulging portion 6 and not on the flat portion 7 (see FIG. 2), but it is also possible to form a flange portion 9 connected to the semi-cylindrical bulging portion 6 and the flat portion. In other words, the outer diameter side edge 6b of each semi-cylindrical bulging portion 6 and the outer diameter side edge 7b of each flat portion (see FIG. 2) may be provided with the flange portion 9 of the outer ring guide.

[0034] When the waveform cage 5A is the outer ring guide, it satisfies the following formulas (5) to (8). φSd=φD×(1.01~1.02) …Equation (5) φHdo=φdo-(0.2~1.0) …Equation (6) φdo+0.1≧φHdi≧φHdo-(Cr×2÷9÷t) …Equation (7) Ra=1.0 or less...Equation (8) The above formula (5) means that the pocket diameter φSd is in the range of 1.01 times or more and 1.02 times or less the diameter φD of the ball 4. The formula (6) means that the outer diameter φHdo of the flange portion 9 is in the range of φdo-1.0 or more and φdo-0.2 or less.

[0035] All parameters are in mm unless otherwise specified. φSd: Pocket diameter φD: ball diameter φHdo: Outer diameter of flange φdo: Outer ring inner diameter φHdi: Inner diameter of the wave holder Cr: Basic dynamic load rating (unit: kN) t: thickness of the corrugated holder (unit: mm) Ra: Roughness of the guideway surface of the flange (arithmetic mean roughness: unit μm) Even in the case of using the outer ring guide type waveform cage 5A, the same effects as those of the above-described embodiment can be achieved.

[0036] In the deep groove ball bearing, a seal member (not shown) that closes the bearing space may be provided on only one side. A lubricating oil other than grease may be used as a lubricant for deep groove ball bearings.

[0037] Although the embodiment for carrying out the present invention has been described above, the embodiment disclosed herein is illustrative in all respects and is not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0038] 1... deep groove ball bearing (rolling bearing), 2... inner ring, 3... outer ring, 4... ball, 5, 5A... corrugated cage, 5a... annular retaining plate, 6... semi-cylindrical bulge, 8... pocket, 9... flange

Claims

1. A rolling bearing comprising a raceway including an inner ring and an outer ring, a plurality of balls interposed between the inner ring and the outer ring, and a corrugated cage for retaining the balls, The corrugated cage is a rolling bearing in which pockets for holding each ball are formed, and a flange portion for guiding a raceway ring is provided on the inner or outer edge of the corrugated cage.

2. 2. The rolling bearing according to claim 1, wherein the pocket is formed in a cylindrical surface.

3. 3. The rolling bearing according to claim 1 or 2, wherein, in the case of an inner ring guide in which the flange portion is provided on an inner diameter edge of the corrugated cage, the rolling bearing satisfies the following formula: φSd=φD×(1.01~1.02) φHdi=φdi+(0.2~1.0) φdo−0.1≧φHdo≧φHdi+(Cr×2÷9÷t) Ra=1.0 or less φSd: Pocket diameter φD: diameter of ball φHdi: Inner diameter of flange φdi: Inner ring outer diameter φdo: Outer ring inner diameter φHdo: Outer diameter of the wave cage Cr: Basic dynamic load rating (unit: kN) t: thickness of the corrugated cage (unit: mm) Ra: Roughness of the guide surface of the flange (arithmetic mean roughness: unit μm)

4. 3. The rolling bearing according to claim 2, wherein the wavy retainer is a wavy retainer formed by combining in the axial direction two annular retaining plates having semi-cylindrical bulges arranged at a predetermined interval along the circumferential direction, and when the two annular retaining plates are combined, the semi-cylindrical bulges face each other to form the pocket forming the cylindrical surface.

5. 3. The rolling bearing according to claim 1 or 2, wherein in the case of an outer ring guide in which the flange portion is provided on the outer diameter edge of the corrugated cage, the rolling bearing satisfies the following formula: φSd=φD×(1.01~1.02) φHdo=φdo-(0.2~1.0) φdo+0.1≧φHdi≧φHdo−(Cr×2÷9÷t) Ra=1.0 or less φSd: Pocket diameter φD: diameter of ball φHdo: Outer diameter of flange φdo: Outer ring inner diameter φHdi: Inner diameter of the wave holder Cr: Basic dynamic load rating (unit: kN) t: thickness of the corrugated cage (unit: mm) Ra: Roughness of the guide surface of the flange (arithmetic mean roughness: unit μm)

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