Retainer, rolling bearing, and method for assembling rolling bearing

Abstract

To prevent displacement of a retainer in an axial direction of a rolling bearing.SOLUTION: A retainer 20 of the present disclosure comprises: a connecting portion 21 that extends in an axial direction in an annular space 14 between an inner ring 11 and an outer ring 12; a first arc portion 22 that extends to one circumferential side from one axial end of the connecting portion 21; a second arc portion 23 that extends to the other circumferential side from the other axial end of the connecting portion 21; a plurality of first projections 24 that protrudes axially from the first arc portion 22 toward the other axial side; and a plurality of second projections 25 that protrudes axially from the second arc portion 23 toward the one axial side. A space between adjacent first projections 24 in the circumferential direction on the other axial side of the first arc portion 22 forms a first pocket 27 in which a part of each of a plurality of balls 13 is accommodated, and a space between adjacent second projections 25 in the circumferential direction on the one axial side of the second arc portion 23 forms a second pocket 28 in which another part of each of the plurality of balls 13 is accommodated.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a cage, a rolling bearing, and a method for assembling a rolling bearing. [Background technology]

[0002] A ball bearing described in Patent Document 1, for example, is known as a thin-walled rolling bearing used in drones and other devices that require weight reduction. This ball bearing includes a cage that holds multiple balls arranged between an inner ring and an outer ring. The cage has an annular body and multiple tines that protrude from the annular body in one axial direction. Pockets are formed between adjacent tines in the circumferential direction to accommodate the balls. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-190240 A Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the cage is assembled in the annular space between the inner and outer rings with a number of balls disposed between the inner and outer rings. When assembled, the cage is disposed on one axial side of the annular space with the tips of each ball facing the annular space. By moving the cage from this state to the other axial side, the cage is assembled in the annular space between the inner and outer rings. For this reason, if acceleration, vibration, or the like occurs during use of the ball bearing, the cage may shift to one axial side of the annular space (the opposite direction to the cage assembly direction). If such a shift occurs, there is a risk of the cage coming into contact with other parts disposed around the ball bearing, causing wear and other problems.

[0005] The present disclosure makes it possible to suppress displacement of a cage in the axial direction of a rolling bearing. [Means for solving the problem]

[0006] A retainer according to the present disclosure is a retainer that is disposed in an annular space between an inner ring and an outer ring of a rolling bearing, and retains a plurality of rolling elements that are disposed in a circumferential direction of the annular space, the retainer comprising: a connecting portion extending in an axial direction in the annular space; a first arc portion extending from an end portion of the connecting portion on one axial side of the annular space to one circumferential side of the annular space; and a second arc portion extending from an end portion of the connecting portion on the other axial side of the annular space to the other circumferential side of the annular space, the first arc portion being spaced apart in the circumferential direction. The rolling elements include a plurality of first rolling elements protruding from the arc portion to the other axial side, and a plurality of second rolling elements arranged at intervals in the circumferential direction on the second arc portion and protruding from the second arc portion to the one axial side, wherein a space between adjacent first rolling elements on the other axial side of the first arc portion is a first pocket in which a portion of the rolling elements is accommodated, and a space between adjacent second rolling elements on the one axial side of the second arc portion is a second pocket in which the other portions of the rolling elements are accommodated.

[0007] The rolling bearing disclosed herein comprises an inner ring, an outer ring, a plurality of rolling elements arranged circumferentially in an annular space between the inner ring and the outer ring, and the retainer arranged in the annular space.

[0008] A method of assembling a rolling bearing according to the present disclosure is a method of assembling a rolling bearing including an inner ring, an outer ring, a plurality of rolling elements arranged in a circumferential direction in an annular space between the inner ring and the outer ring, and the cage arranged in the annular space, wherein, with the plurality of rolling elements arranged between the inner ring and the outer ring, the method comprises moving the end of the first arc-shaped portion from the other axial direction side towards the one axial direction side, or moving the end of the second arc-shaped portion from the one axial direction side towards the other axial direction side, between adjacent rolling elements at any position in the circumferential direction in the annular space, a first step of penetrating the connecting portion into the annular space from the one axial direction side to the annular space; a second step of placing the connecting portion in the annular space to expose the first arc portion toward the one axial direction side from the annular space and to expose the second arc portion toward the other axial direction side from the annular space; and a third step of inserting the first arc portion into the annular space from the one axial direction side to accommodate the some of the plurality of rolling elements in the first pocket and inserting the second arc portion into the annular space from the other axial direction side to accommodate the other portions of the plurality of rolling elements in the second pocket. Effect of the Invention

[0009] According to the present disclosure, it is possible to suppress the retainer from shifting in the axial direction of the rolling bearing. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing a rolling bearing according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line II in FIG. [Diagram 3] FIG. [Figure 4] FIG. 2 is a perspective view showing a rolling bearing in the middle of assembly, in the state before a cage is fitted into the annular space between the inner and outer rings. [Diagram 5] 1 is a perspective view showing a rolling bearing in the middle of assembly, in which a connecting portion of a cage is disposed in an annular space. [Figure 6]6 is a perspective view showing a state in the middle of assembling the rolling bearing, in which the cage has been elastically deformed from the state shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First, the contents of the embodiment will be listed and described. <Overview of the embodiment> (1) A retainer disclosed herein is a retainer that is disposed in an annular space between an inner ring and an outer ring of a rolling bearing and retains a plurality of rolling elements that are disposed in a circumferential direction of the annular space, the retainer comprising: a connecting portion extending in an axial direction in the annular space; a first arc portion extending from an end portion of the connecting portion on one axial side of the annular space to one circumferential side of the annular space; and a second arc portion extending from an end portion of the connecting portion on the other axial side of the annular space to the other circumferential side of the annular space, the first arc portion being spaced apart in the circumferential direction. The rolling elements include a plurality of first rolling elements protruding from the arc portion toward the other axial direction, and a plurality of second rolling elements arranged at intervals in the circumferential direction on the second arc portion and protruding from the second arc portion toward the one axial direction, wherein a space between adjacent first rolling elements on the other axial side of the first arc portion is a first pocket in which a portion of the rolling elements is accommodated, and a space between adjacent second rolling elements on the one axial side of the second arc portion is a second pocket in which the other portions of the rolling elements are accommodated.

[0012] According to the present disclosure, the rolling elements are accommodated in the first pocket on the other axial side of the first arc portion, so that the first arc portion comes into contact with the rolling elements accommodated in the first pocket, thereby restricting the cage from moving to the other axial side of the annular space between the inner and outer rings. Also, the rolling elements are accommodated in the second pocket on one axial side of the second arc portion, so that the second arc portion comes into contact with the rolling elements accommodated in the second pocket, thereby restricting the cage from moving to one axial side of the annular space between the inner and outer rings. This makes it possible to suppress the cage from shifting in the axial direction of the rolling bearing.

[0013] (2) In the rolling bearing described in (1) above, it is preferable that the end portion of the first arc portion on one circumferential side and the end portion of the second arc portion on the other circumferential side are arranged with a gap in the circumferential direction. In this case, since the cage is formed into a C-shape overall, the cage can be easily fitted into the annular space between the inner and outer rings.

[0014] (3) The rolling bearing of the present disclosure comprises an inner ring, an outer ring, a plurality of rolling elements arranged circumferentially in an annular space between the inner ring and the outer ring, and a retainer of (1) or (2) arranged in the annular space. The above rolling bearing provides the same effects as those of the above cage.

[0015] (4) A method of assembling a rolling bearing disclosed herein is a method of assembling a rolling bearing including an inner ring, an outer ring, a plurality of rolling elements arranged in the circumferential direction in an annular space between the inner ring and the outer ring, and a cage according to (2) arranged in the annular space, wherein, with the plurality of rolling elements arranged between the inner ring and the outer ring, the end of the first arc-shaped portion is moved from the other axial side towards the one axial side, or the end of the second arc-shaped portion is moved from the one axial side towards the one axial side towards the axial side, between adjacent rolling elements at any position in the circumferential direction in the annular space. a first step of penetrating the connecting portion toward the other axial side; a second step of disposing the connecting portion in the annular space to expose the first arc portion toward the one axial side relative to the annular space and to expose the second arc portion toward the other axial side relative to the annular space; and a third step of inserting the first arc portion into the annular space from the one axial side to accommodate the some of the plurality of rolling bodies in the first pocket, and inserting the second arc portion into the annular space from the other axial side to accommodate the other portions of the plurality of rolling bodies in the second pocket, in that order.

[0016] The above-mentioned method for assembling a rolling bearing provides the same effects as the above-mentioned cage. Also, the end of the first arc portion or the end of the second arc portion of the cage is inserted axially into the annular space, and the connecting portion of the cage is disposed in the annular space between the inner and outer rings. In this state, the first arc portion exposed on one axial side from the annular space and the second arc portion exposed on the other axial side from the annular space are inserted into the annular space, respectively, to accommodate multiple rolling elements in the first pocket and the second pocket. This allows the cage to be easily assembled into the annular space between the inner and outer rings.

[0017] <Details of the embodiment> Hereinafter, preferred embodiments will be described with reference to the drawings. [Structure of rolling bearings] Fig. 1 is a front view showing a rolling bearing 10 according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II in Fig. 1. In Figs. 1 and 2, the rolling bearing 10 is a thin-walled rolling bearing used in drones and the like. The rolling bearing 10 of this embodiment is, for example, a deep groove ball bearing. The rolling bearing 10 includes an inner ring 11, an outer ring 12, a plurality of balls (rolling elements) 13, and a cage 20.

[0018] In this disclosure, the direction along the central axis C of the rolling bearing 10 is the axial direction of the rolling bearing 10, and is simply referred to as the "axial direction." The axial direction also includes a direction parallel to the central axis C. The direction perpendicular to the central axis C is the radial direction of the rolling bearing 10, and is simply referred to as the "radial direction." The direction along a circle centered on the central axis C is the circumferential direction of the rolling bearing 10, and is simply referred to as the "circumferential direction."

[0019] The inner ring 11 is annular. The outer ring 12 is arranged radially outward of the inner ring 11. The outer ring 12 is annular. A plurality of balls 13 are arranged circumferentially in an annular space 14 between the inner ring 11 and the outer ring 12. The outer peripheral surface of the inner ring 11 has an inner ring raceway surface 11a on which the balls 13 roll. The cross-sectional shape of the inner ring raceway surface 11a is a substantially concave arc shape that opens radially outward. The inner peripheral surface of the outer ring 12 has an outer ring raceway surface 12a on which the balls 13 roll. The cross-sectional shape of the outer ring raceway surface 12a is a substantially concave arc shape that opens radially inward.

[0020] [Cage configuration] FIG. 3 is a perspective view showing the cage 20. As shown in FIGS. 1 to 3, the cage 20 is disposed in the annular space 14. The cage 20 holds the plurality of balls 13 so that they can roll freely. The cage 20 is made of an elastically deformable synthetic resin. The cage 20 is made of a single member formed into a C-shape along the circumferential direction of the annular space 14. The radial thickness of the cage 20 is uniform throughout the entire circumferential direction.

[0021] The cage 20 includes a connecting portion 21, a first arc portion 22, a second arc portion 23, a plurality of first portions 24, and a plurality of second portions 25. The connecting portion 21 has a linear shape. The connecting portion 21 is arranged in the annular space 14, extending in the axial direction. The connecting portion 21 has a function of connecting the first arc portion 22 and the second arc portion 23. The first arc portion 22 and the second arc portion 23 are each integrally provided with the connecting portion 21. The first arc portion 22 and the second arc portion 23 are both approximately semicircular. In this embodiment, the circumferential length of the first arc portion 22 and the circumferential length of the second arc portion 23 are the same.

[0022] The first arc portion 22 extends from an end of the connecting portion 21 on one axial side (left side in Fig. 2; same below) of the annular space 14 to one circumferential side (counterclockwise side in Fig. 1; same below) of the annular space 14. The second arc portion 23 extends from an end of the connecting portion 21 on the other axial side (right side in Fig. 2; same below) of the annular space 14 to the other circumferential side (clockwise side in Fig. 1; same below) of the annular space 14. The end 22a on one circumferential side of the first arc portion 22 and the end 23a on the other circumferential side of the second arc portion 23 are arranged opposite each other with a gap 26 in the circumferential direction.

[0023] The multiple first portions 24 are integrally provided at intervals in the circumferential direction on the first arc portion 22. The first portions 24 are substantially linear. The first portions 24 protrude from the first arc portion 22 to the other axial side. The axial length of the first portions 24 is set to a length that does not protrude beyond the second arc portion 23 to the other axial side.

[0024] The second portions 25 are integrally provided at intervals in the circumferential direction on the second arc portion 23. The second portions 25 are substantially linear. The second portions 25 protrude from the second arc portion 23 to one side in the axial direction. The axial length of the second portions 25 is set to a length that does not protrude beyond the first arc portion 22 to one side in the axial direction.

[0025] The cage 20 has a plurality of first pockets 27 and a plurality of second pockets 28. The first pockets 27 each hold half (a portion) of the plurality of balls 13 in a rollable manner. The second pockets 28 each hold the remaining half (other portions) of the plurality of balls 13 in a rollable manner.

[0026] The first pockets 27 are spaces formed between the first pockets 24 adjacent to each other in the circumferential direction on the other axial side of the first arc portion 22. In this embodiment, the multiple first pockets 27 include a predetermined number of arc-shaped first pockets 27A and a predetermined number of recessed first pockets 27B. The first pockets 27A and the first pockets 27B are arranged alternately in the circumferential direction.

[0027] An opening width D11 on the other axial side of the first pocket 27A is smaller than a diameter D3 (see FIG. 2) of the ball 13. By elastically deforming the first 24s located on both circumferential sides of the first pocket 27A so as to move away from each other, the ball 13 can be accommodated in the first pocket 27A from the other axial side of the first pocket 27A.

[0028] The opening width D12 on the other axial side of the first pocket 27B is considerably larger than the diameter D3 of the ball 13. When the first balls 24 located on both circumferential sides of the first pocket 27B are elastically deformed as described above, the opening width D12 of the first pocket 27B temporarily becomes smaller. However, even if the opening width D12 becomes temporarily smaller in this manner, the opening width D12 is set to be larger than the diameter D3 of the ball 13. Therefore, even if the first balls 24 located on both circumferential sides of the first pocket 27B are elastically deformed to approach each other, the ball 13 can be accommodated in the first pocket 27B from the other axial side of the first pocket 27B.

[0029] The second pocket 28 is a space formed between the second pockets 25 adjacent to each other in the circumferential direction on one axial side of the second arc portion 23. In this embodiment, the multiple second pockets 28 include a predetermined number of arc-shaped second pockets 28A and a predetermined number of recessed second pockets 28B. The second pockets 28A and the second pockets 28B are arranged alternately in the circumferential direction.

[0030] An opening width D21 on one axial side of the second pocket 28A is the same as an opening width D11 of the first pocket 27A. Therefore, by elastically deforming the second 25 located on both circumferential sides of the second pocket 28A so as to move away from each other, the balls 13 can be accommodated in the second pocket 28A from one axial side of the second pocket 28A.

[0031] An opening width D22 on one axial side of the second pocket 28B is the same as an opening width D12 of the first pocket 27B. Therefore, even if the second balls 25 located on both circumferential sides of the second pocket 28B elastically deform so as to approach each other, the balls 13 can be accommodated in the second pocket 28B from one axial side of the second pocket 28B.

[0032] [How to assemble rolling bearings] Next, a method of assembling the rolling bearing 10 will be described. Figures 4, 5, and 6 are perspective views showing a state in the middle of assembling the rolling bearing 10. Here, a method of fitting the cage 20 into the annular space 14 between the inner ring 11 and the outer ring 12 in a state in which a plurality of balls 13 are arranged in advance between the inner ring 11 and the outer ring 12 as shown in Figure 4 will be described.

[0033] First, from the state shown in Fig. 4, end 22a of first arc portion 22 of cage 20 (see Fig. 3) is penetrated from the other axial side to one axial side of annular space 14 between adjacent balls 13 at any circumferential position in annular space 14 (first step). Note that in this first step, end 23a of second arc portion 23 may also be penetrated from one axial side to the other axial side of annular space 14.

[0034] Next, the first arc portion 22 is further moved toward one side in the axial direction, and the connecting portion 21 of the retainer 20 is disposed in the annular space 14, as shown in Fig. 5. As a result, the first arc portion 22 and the plurality of first portions 24 (excluding the connecting portion 21) are exposed toward one side in the axial direction relative to the annular space 14. Also, the second arc portion 23 and the plurality of second portions 25 (excluding the connecting portion 21) are exposed toward the other side in the axial direction relative to the annular space 14 (second step).

[0035] 6, the cage 20 is elastically deformed so that the end 22a of the first arc portion 22 and the end 23a of the second arc portion 23 move away from each other in the axial direction, and the first arc portion 22 and the second arc portion 23 are inserted into the annular space 14. At that time, the tips of the first balls 24 on the first arc portion 22 side are inserted into the annular space 14 one by one from one axial side, and the tips of the second balls 25 on the second arc portion 23 side are inserted into the annular space 14 one by one from the other axial side. As a result, the balls 13 are accommodated in the first pockets 27 on the first arc portion 22 side, and the balls 13 are accommodated in the second pockets 28 on the second arc portion 23 side (third step).

[0036] Specifically, the first pockets 24 located on both circumferential sides of each first pocket 27A on the first arc portion 22 side are inserted into the annular space 14 and come into contact with the ball 13, so that they elastically deform away from each other along the outer circumferential surface of the ball 13. As a result, the ball 13 is accommodated in each first pocket 27A on the first arc portion 22 side. At that time, the opening width D12 (see FIG. 3) of each first pocket 27B temporarily decreases as described above, but since the opening width D12 is larger than the diameter D3 of the ball 13, the ball 13 is also accommodated in each first pocket 27B on the first arc portion 22 side.

[0037] The second pockets 25 located on both circumferential sides of each second pocket 28A on the second arc portion 23 side are elastically deformed to move away from each other along the outer circumferential surface of the ball 13 by being inserted into the annular space 14 and coming into contact with the ball 13. This causes the ball 13 to be accommodated in each second pocket 28A on the second arc portion 23 side. At that time, the opening width D22 (see FIG. 3) of each second pocket 28B temporarily becomes small as described above, but since the opening width D22 is larger than the diameter D3 of the ball 13, the ball 13 is also accommodated in each second pocket 28B on the second arc portion 23 side.

[0038] [Effects of the embodiment] According to the rolling bearing 10 and the retainer 20 of this embodiment, the balls 13 are accommodated in the first pocket 27 on the other axial side of the first arc portion 22, so that the first arc portion 22 comes into contact with the balls 13 accommodated in the first pocket 27, thereby restricting the retainer 20 from moving to the other axial side of the annular space 14 between the inner ring 11 and the outer ring 12. Also, the balls 13 are accommodated in the second pocket 28 on one axial side of the second arc portion 23, so that the second arc portion 23 comes into contact with the balls 13 accommodated in the second pocket 28, thereby restricting the retainer 20 from moving to one axial side of the annular space 14. This makes it possible to suppress the retainer 20 from shifting in the axial direction of the rolling bearing 10.

[0039] An end 22a on one circumferential side of the first arc-shaped portion 22 and an end 23a on the other circumferential side of the second arc-shaped portion 23 are disposed with a circumferential gap 26 therebetween. As a result, the retainer 20 is formed into a C-shape as a whole, so that the retainer 20 can be easily incorporated into the annular space 14 between the inner ring 11 and the outer ring 12.

[0040] In the method of assembling the rolling bearing 10 of this embodiment, the end 22a of the first arc portion 22 or the end 23a of the second arc portion 23 of the cage 20 is inserted into the annular space 14 in the axial direction, and the connecting portion 21 of the cage 20 is disposed in the annular space 14 between the inner ring 11 and the outer ring 12. In this state, the first arc portion 22 exposed on one axial side from the annular space 14 and the second arc portion 23 exposed on the other axial side from the annular space 14 are inserted into the annular space 14, respectively, to accommodate the multiple balls 13 in the first pocket 27 and the second pocket 28. This allows the cage 20 to be easily assembled into the annular space 14 between the inner ring 11 and the outer ring 12.

[0041] [others] The embodiments disclosed above are illustrative in all respects and are not limiting. For example, the rolling bearing 10 may be a three-point contact ball bearing or a four-point contact ball bearing, in addition to a deep groove ball bearing. The cage 20 may include a plurality of connecting portions 21.

[0042] In this embodiment, the circumferential length of the first arc portion 22 and the circumferential length of the second arc portion 23 of the retainer 20 are the same, but may be different from each other. In this embodiment, a gap 26 is provided between the ends 22a, 23a of the first arc portion 22 and the second arc portion 23, but these ends 22a, 23a may be butted against each other or overlapped in the radial direction and fixed with an adhesive or the like. The multiple first pockets 27 may all have the same shape. Similarly, the multiple second pockets 28 may all have the same shape. [Explanation of symbols]

[0043] 10. Rolling bearings 11. Inner Circle 12 Outer ring 13 Ball (rolling element) 14 Annular Space 20 Retainer 21 Connecting part 22 First arc 22a end 23 Second arc section 23a End 24 First 25 Second 26 Gap 27 First Pocket 28 Second Pocket

Claims

1. A cage that is disposed in an annular space between an inner ring and an outer ring of a rolling bearing and holds a plurality of rolling elements that are disposed in a circumferential direction of the annular space, a coupling portion extending axially in the annular space; a first arc portion extending from an end portion of the connecting portion on one axial side of the annular space toward one circumferential side of the annular space; a second arc portion extending from an end portion of the connecting portion on the other axial side of the annular space toward the other circumferential side of the annular space; a plurality of first grooves provided at intervals in a circumferential direction in the first arc portion and protruding from the first arc portion to the other side in the axial direction; a plurality of second arcuate projections provided at intervals in a circumferential direction in the second arcuate portion and protruding from the second arcuate portion to one side in the axial direction; a space between the first arcuate portions adjacent to each other in the circumferential direction on the other axial side of the first arcuate portion is a first pocket in which some of the rolling elements are accommodated, A cage, wherein the space between the second arc portions adjacent to each other in the circumferential direction on one axial side of the second arc portion is a second pocket in which the other portions of the plurality of rolling elements are accommodated.

2. The cage according to claim 1 , wherein an end portion on one circumferential side of the first arcuate portion and an end portion on the other circumferential side of the second arcuate portion are disposed with a gap therebetween in the circumferential direction.

3. 3. A rolling bearing comprising: an inner ring; an outer ring; a plurality of rolling elements arranged circumferentially in an annular space between the inner ring and the outer ring; and a cage according to claim 1 or 2 arranged in the annular space.

4. 3. A method for assembling a rolling bearing including an inner ring, an outer ring, a plurality of rolling elements arranged in a circumferential direction in an annular space between the inner ring and the outer ring, and the cage according to claim 2 arranged in the annular space, comprising the steps of: a first step of penetrating the end of the first arc-shaped portion from the other axial side toward the one axial side or penetrating the end of the second arc-shaped portion from the one axial side toward the other axial side between adjacent rolling elements at any circumferential position in the annular space with a plurality of rolling elements disposed between the inner ring and the outer ring; a second step of exposing the first arc portion to one side in the axial direction relative to the annular space and exposing the second arc portion to the other side in the axial direction relative to the annular space by disposing the connecting portion in the annular space; a third step of inserting the first arc portion into the annular space from one axial side to accommodate the some of the plurality of rolling elements in the first pocket, and a third step of inserting the second arc portion into the annular space from the other axial side to accommodate the other portions of the plurality of rolling elements in the second pocket.

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