Cage for angular ball bearing

Abstract

To provide a cage of an angular ball bearing capable of enhancing the loading efficiency of balls from the radial outside.SOLUTION: The cage includes an inner ring 34, an outer ring 35, and a partition wall 45. The partition wall 45 connects the inner ring 34 and the outer ring 35 at a plurality of positions spaced apart from each other in the circumferential direction, and partitions the plurality of balls 32 arranged along the inner ring 34 and the outer ring 35. The partition wall 45 slidably holds the balls 32 together with the inner ring 34 in a state where a part of the balls 32 protrudes radially inward from the inner peripheral surface of the inner ring 34 and another part of the balls 32 protrudes radially outward from the outer peripheral surface of the outer ring 35. Each of the partition walls 45 is provided with a cutout portion 46 that opens from a closest region 50 where the adjacent balls 32 are closest to each other toward a radially outer side of the closest region 50.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a cage for an angular contact ball bearing that holds a plurality of balls. [Background technology]

[0002] Angular contact ball bearings have a structure in which multiple balls held in an annular cage are in rolling contact with an outer ring and an inner ring. Most cages have multiple pockets that individually hold each ball so that it can slide, and each ball rolls within a corresponding pocket.

[0003] Increasing the number of balls held in the cage is a known method for improving the durability of the rolling elements of such angular contact ball bearings. However, in typical angular contact ball bearings, the number of balls that can be loaded into the cage is limited because pocket walls exist between adjacent balls in the cage.

[0004] To address this issue, a cage has been devised in which a notch is provided in the partition wall located between adjacent balls, so that the closest portions of the adjacent balls are positioned within this notch (see, for example, Patent Document 1).

[0005] The cage described in Patent Document 1 has an inner ring and an outer ring that are coaxially arranged but offset in the axial direction, and are connected by multiple partition walls. The multiple partition walls are arranged spaced apart in the circumferential direction, and balls, which are rolling elements, can be arranged between adjacent partition walls in the circumferential direction. Each partition wall is arranged in an offset region of the inner ring and the outer ring in the axial direction, and each partition wall extends in the radial direction. Each partition wall has a U-shaped opening so that the nearest region, where adjacent balls are closest to each other, becomes a space.

[0006] Furthermore, in the cage described in Patent Document 1, openings are formed in the peripheral wall of the outer ring, allowing a portion of each ball to protrude radially outward beyond the outer peripheral surface of the outer ring. The radially inner ends of each of the partition walls extend from the axial end of the inner ring facing the outer ring. Arc-shaped recesses are formed between the radially inner ends of adjacent partition walls in the circumferential direction. These arc-shaped recesses allow a portion of the corresponding ball to protrude radially inward beyond the inner peripheral surface of the inner ring. The inner surfaces of each opening in the outer ring and the recesses between the partition walls are formed spherically, and these spherical inner surfaces hold the corresponding balls in a rollable manner.

[0007] In this cage, a U-shaped opening is formed in the partition wall in the region where adjacent balls are closest to each other. This means that the apexes of adjacent balls are closer to each other than the thickness of the partition wall. Therefore, when this cage is used, by bringing adjacent balls sufficiently close to each other, it is possible to load more balls around the circumference. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5768562 Summary of the Invention [Problem to be solved by the invention]

[0009] In the manufacturing process of angular contact ball bearings, it is desirable to load the balls (rolling elements) into the cage from the radial outside in terms of loading workability. In other words, if balls are to be loaded into the cage from the radial inside, it becomes necessary to move the loaded balls into the cage's inner ring, which has limited space. In this case, the mechanism for loading multiple balls becomes complicated, making it difficult to efficiently load the balls into the cage.

[0010] For this reason, in the case of the cage described in Patent Document 1, the balls, which are rolling elements, are loaded into the cage from the radially outer side. However, with the cage described in Patent Document 1, when loading balls, it is necessary to push open the opening of the outer ring to press the balls inward. At this time, because the opening of the outer ring forms a substantially annular shape closed together with the partition wall, excessive stress is likely to act on the periphery of the opening when the opening is pushed open to press the balls inward. For this reason, it is difficult to improve the ball loading efficiency with the cage described in Patent Document 1.

[0011] The present invention provides a cage for an angular contact ball bearing that can increase the efficiency of loading balls from the radially outer side. [Means for solving the problem]

[0012] A retainer for an angular contact ball bearing according to one embodiment of the present invention comprises an inner ring, an outer ring whose inner diameter is larger than the outer diameter of the inner ring and which is arranged coaxially with the inner ring, and a plurality of partition walls which connect the inner ring and the outer ring at a plurality of circumferentially spaced locations and which separate the inner ring from a plurality of balls arranged along the outer ring, wherein the partition walls slidably hold the balls together with the inner ring, with some of the balls protruding radially inward from the inner surface of the inner ring and other parts of the balls protruding radially outward from the outer surface of the outer ring, and each of the partition walls is provided with a notch which opens from the nearest region where adjacent balls are closest to each other toward the radially outward side of the nearest region.

[0013] In this cage, each ball is slidably held by the inner ring and the partition wall with a portion of the ball protruding radially inward beyond the inner peripheral surface of the inner ring and another portion of the ball protruding radially outward beyond the outer peripheral surface of the outer ring. Each partition wall has a notch that opens radially outward from the closest region of adjacent balls, allowing adjacent balls to be spaced closer to each other by a distance greater than the thickness of the partition wall (the thickness of the central region). Therefore, a larger number of balls can be loaded into this cage. Furthermore, in this cage, the notch in each partition wall opens radially outward from the nearest region. Therefore, the radially outer end of each partition wall is connected to the outer ring in a cantilevered manner, and the axial protrusion length from the outer ring is kept sufficiently short. Therefore, when loading balls from the radially outer side of the outer ring, simply by pushing the balls in and slightly bending the outer-ring-side end of the partition wall, the balls can be easily loaded into the holding portion (pocket portion) formed by the inner ring and the two partition walls.

[0014] According to another aspect of the present invention, a cage for an angular contact ball bearing includes an inner ring, an outer ring having an inner diameter larger than the outer diameter of the inner ring, arranged coaxially with the inner ring but offset in the axial direction relative to the inner ring, a plurality of connecting walls connecting the inner ring and the outer ring at a plurality of circumferentially spaced locations and restricting circumferential movement of each of a plurality of balls arranged along the circumferential direction of the inner ring and the outer ring, and a plurality of outer protrusions protruding from an axial end of the outer ring on the inner ring side and restricting circumferential movement of each of the plurality of balls together with the connecting walls, An opening is formed in the ring and each of the two circumferentially adjacent connecting walls to slidably hold the ball so that a portion of the ball protrudes radially inward beyond the inner surface of the inner ring, and a recess is formed between each of the two circumferentially adjacent outer protrusions to slidably hold the ball so that another portion of the ball protrudes radially outward beyond the outer surface of the outer ring, the connecting wall and the outer protrusions are positioned at a position shifted from the closest region in which the adjacent balls are closest to each other, and the protruding length of each outer protrusion from the axial end of the outer ring is set shorter than the axial length from that end to the closest region.

[0015] In this cage, each ball is slidably held by openings formed in the inner ring and each of the two adjacent connecting walls, and by recesses formed between the two adjacent outer projections. Because the connecting walls and the outer projections are positioned away from the areas where the adjacent balls are closest to each other, the adjacent balls can be positioned closer to each other than the thickness of the connecting walls. Therefore, a larger number of balls can be loaded into the cage. Furthermore, in the cage of this configuration, the protrusion length of each outer protrusion from the axial end of the outer ring is set shorter than the axial length from that end to the closest region. As a result, each outer protrusion does not protrude significantly from the axial end of the outer ring toward the closest region. Therefore, when loading balls from the radial outside of the outer ring, simply by pushing the balls in and slightly bending the outer protrusions, the balls can be easily loaded into the holding portions (pockets) formed by the openings and recesses.

[0016] In the retainer of the angular contact ball bearing described above, it is desirable that the opening has an arc-shaped inner opening edge at the portion facing the radially inner space of the inner ring, and the recess has an arc-shaped outer opening edge at the portion facing the radially outer space of the outer ring, and that the radius of the arc of the outer opening edge is set to be larger than the radius of the arc of the inner opening edge, and that the radius of the arc of the inner opening edge is set to be smaller than the radius of the spherical surface of the ball.

[0017] In this case, because the radius of the arc of the outer opening edge of the recess is set larger than the radius of the arc of the inner opening edge of the opening, it is easy to load the ball from the radial outside of the outer ring through the outer opening edge. Also, because the radius of the arc of the inner opening edge of the opening is set smaller than the radius of the spherical surface of the ball, it is difficult to load the ball from the radial inside of the inner ring through the inner opening edge. Therefore, if the radius of the arc of the inner opening edge of the opening is set to a dimension that reliably restricts the entry of the ball, it is possible to prevent the ball from being forcibly assembled from the wrong direction.

[0018] It is desirable that both the inner ring and the outer ring be formed of an annular body that is continuous in the circumferential direction.

[0019] In this case, because the radially inner ball holding portion and the radially outer ball holding portion are each formed of a continuous annular body, the cage can be maintained in a stable shape when balls are loaded into the cage or when it is being transported. Therefore, when this configuration is adopted, the cage can be easily handled when balls are loaded into the cage or when it is being transported. [Effects of the Invention]

[0020] According to the cage of the angular contact ball bearing described above, it is possible to improve the efficiency of loading the balls from the radially outer side. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a longitudinal sectional view of a reducer employing an angular contact ball bearing according to an embodiment; [Figure 2] FIG. 1 is a perspective view of an angular contact ball bearing according to an embodiment. [Figure 3] FIG. 2 is a perspective view of a cage holding a plurality of balls according to an embodiment. [Figure 4] FIG. 3 is a perspective view of the cage according to the embodiment, seen from one direction. [Figure 5] FIG. 4 is a perspective view of the cage of the embodiment as viewed from the opposite direction. [Figure 6] FIG. 2 is a partially cross-sectional perspective view showing a retainer according to the embodiment; [Figure 7] 7 is a cross-sectional view of the cage according to the embodiment taken along line VII-VII in FIG. 4. [Figure 8] 8 is a cross-sectional view of the cage according to the embodiment taken along line VIII-VIII in FIG. 4. [Figure 9] 9 is a cross-sectional view of the cage according to the embodiment taken along line IX-IX in FIG. 4. [Figure 10] FIG. 4 is a partial cross-sectional perspective view of the cage showing a state in which balls are loaded in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, an embodiment of the present invention will be described with reference to the drawings.

[0023] <Reducer> FIG. 1 is a vertical cross-sectional view of a reducer 10 that employs an angular contact ball bearing 12 according to this embodiment. The reducer 10 comprises an outer cylinder 11, a first carrier block 13A and a second carrier block 13B rotatably held on the inner surface of the outer cylinder 11, a plurality of (e.g., three) crankshafts 14 rotatably supported by the first carrier block 13A and the second carrier block 13B, and a first oscillating gear 15A and a second oscillating gear 15B that rotate together with the two eccentric portions 14a, 14b of each crankshaft 14.

[0024] The first carrier block 13A is formed in the shape of a perforated disk. The second carrier block 13B has a perforated disk-shaped base plate 13Ba and a plurality (three) of support columns 13Bb extending from an end face of the base plate 13Ba toward the first carrier block 13A. The support columns 13Bb are arranged at equal intervals around the rotational center axis c1 of the carrier blocks (first carrier block 13A and second carrier block 13B). The end faces of the support columns 13Bb of the second carrier block 13B are abutted against the end faces of the first carrier block 13A, and each support column 13Bb is fastened and fixed to the first carrier block 13A with a plurality of fastening members 16. In addition, reference numeral 18 in the drawing denotes a positioning pin that is driven in before fastening the support column portion 13Bb to the first carrier block 13A with the fastening member 16.

[0025] Additionally, an axial gap is secured between the base plate portions 13Ba of the first carrier block 13A and the second carrier block 13B by the support portions 13Bb, and a first oscillating gear 15A and a second oscillating gear 15B are disposed in this gap. The first oscillating gear 15A and the second oscillating gear 15B are formed with relief holes 19 through which the support pillars 13Bb of the second carrier block 13B pass. The relief holes 19 are formed with an inner diameter that is sufficiently larger than the support pillars 13Bb so that the support pillars 13Bb do not interfere with the rotational movement of the first oscillating gear 15A and the second oscillating gear 15B.

[0026] The outer cylinder 11 is disposed across the outer peripheral surface of the first carrier block 13A and the outer peripheral surface of the base plate portion 13Ba of the second carrier block 13B. Both axial end regions of the outer cylinder 11 are supported by the first carrier block 13A and the base plate portion 13Ba of the second carrier block 13B via angular contact ball bearings 12, respectively, so as to be rotatable relative to each other. The specific structure of these angular contact ball bearings 12 will be described in detail later.

[0027] Furthermore, a plurality of pin grooves 25 extending parallel to the rotation center axis c1 are formed on the inner peripheral surface of the central region in the axial direction of the outer cylinder 11 (region facing the outer peripheral surfaces of the first oscillatory gear 15A and the second oscillatory gear 15B). A substantially cylindrical internally toothed pin 20 is rotatably housed in each pin groove 25. The multiple internally toothed pins 20 attached to the inner peripheral surface of the outer cylinder 11 face the outer peripheral surfaces of the first oscillatory gear 15A and the second oscillatory gear 15B.

[0028] The first oscillating gear 15A and the second oscillating gear 15B are formed with an outer diameter slightly smaller than the inner diameter of the outer cylinder 11. On the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B, external teeth 15Aa and 15Ba are formed which come into meshing contact with a plurality of internally toothed pins 20 arranged on the inner peripheral surface of the outer cylinder 11. The number of teeth of the external teeth 15Aa and 15Ba formed on the outer peripheral surfaces of the first oscillating gear 15A and the second oscillating gear 15B is set to be slightly less (for example, one less) than the number of internally toothed pins 20 (the number of internal teeth).

[0029] The multiple crankshafts 14 are arranged on the same circumference, centered on the rotational central axis c1 of the first carrier block 13A and the second carrier block 13B. Each crankshaft 14 is rotatably supported by the first carrier block 13A and the second carrier block 13B via bearings 21. The eccentric portions 14a and 14b of each crankshaft 14 pass through the first oscillating gear 15A and the second oscillating gear 15B, respectively. Each eccentric portion 14a and 14b is rotatably engaged with a support hole 22 formed in the first oscillating gear 15A and the second oscillating gear 15B, respectively, via an eccentric portion bearing 23. The two eccentric portions 14a and 14b of each crankshaft 14 are eccentric so that they are 180° out of phase with each other around the axis of the crankshaft 14.

[0030] When the multiple crankshafts 14 rotate in one direction due to an external force (for example, the driving force of an electric motor), the eccentric portions 14a, 14b of the crankshafts 14 revolve in the same direction at a predetermined radius, and accordingly the first oscillating gear 15A and the second oscillating gear 15B revolve (oscillate) in the same direction at the same radius. At this time, the external teeth 15Aa, 15Ba of the first oscillating gear 15A and the second oscillating gear 15B come into contact with the multiple internal tooth pins 20 held on the inner circumference of the outer cylinder 11 so as to mesh with each other. One end of each crankshaft 14 penetrates the first carrier block 13A and protrudes axially outward from the first carrier block 13A. A crankshaft gear 28 is attached to the end of each crankshaft 14 protruding from the first carrier block 13A. Each crankshaft gear 28 meshes with an input gear (not shown). The input gear rotates by receiving driving force from an electric motor (not shown). In this embodiment, the outer cylinder 11 is fixed to a device or a fixed block (not shown).

[0031] In this reducer 10, the number of teeth of each of the external teeth 15Aa, 15Ba of the first oscillating gear 15A and the second oscillating gear 15B is set slightly less than the number of internal tooth pins 20 on the outer cylinder 11 side. Therefore, while the first oscillating gear 15A and the second oscillating gear 15B make one revolution, the first oscillating gear 15A and the second oscillating gear 15B receive a rotational reaction force from the internal tooth pins 20 on the outer cylinder 11 side, and rotate a predetermined pitch in the direction opposite to the revolution direction. As a result, the first and second carrier blocks 13A, 13B engaged with the first oscillating gear 15A and the second oscillating gear 15B via the crankshaft 14 rotate in the same direction and at the same pitch together with the first and second oscillating gears 15A, 15B. As a result, the rotation of the crankshaft 14 is decelerated and output as the rotation of the first and second carrier blocks 13A, 13B. In this embodiment, the eccentric portions 14a, 14b of each crankshaft 14 are eccentric so as to be shifted by 180° around the axis, so the rotation phases of the first oscillating gear 15A and the second oscillating gear 15B are shifted by 180°.

[0032] <Angular contact ball bearing> Next, the specific structure of the angular contact ball bearing 12 of this embodiment will be described with reference to FIGS. In the angular ball bearing 12 shown in Figure 1, the inner ring 30, which will be described later, is integrated with the base plate portion 13Ba of the first carrier block 13A and the second carrier block 13B, but in Figures 2 and 7 to 9, it is shown as a separate inner ring 30.

[0033] FIG. 2 is a perspective view of the angular contact ball bearing 12 of this embodiment. The angular contact ball bearing 12 includes an inner ring 30 disposed radially inside, an outer ring 31 disposed radially outside, a plurality of balls 32 as rolling elements interposed between the inner ring 30 and the outer ring 31, and an annular cage 33 that holds the plurality of balls 32. In the above-described reducer 10, the inner ring 30 is integrated with the first carrier block 13A or the second carrier block 13B. However, the inner ring 30 may be formed as a separate component and fixed to the first carrier block 13A or the second carrier block 13B. In the above-described reducer 10, the outer ring 31 is fixed to the outer cylinder 11. However, the outer ring 31 may be integrated with the outer cylinder 11.

[0034] Fig. 3 is a perspective view of a cage 33 holding a plurality of balls 32, and Fig. 4 is a perspective view of the cage 33 from which all but one of the balls 32 have been removed. Figs. 3 and 4 are views of the cage 33 as seen from the side on which the outer ring 31 is placed. Fig. 5 is a perspective view of the cage 33 as seen from the side on which the inner ring 30 is placed. Fig. 5 shows a state in which all but one of the balls 32 have been removed, as in Fig. 4. Fig. 6 is a partial cross-sectional perspective view of the cage 33 shown in Fig. 4. The cage 33 of this embodiment is made of a resin material and is formed by, for example, injection molding. As shown in FIGS. 3 to 6 , the cage 33 includes an inner ring 34, an outer ring 35 arranged coaxially with the inner ring 34, a plurality of connecting walls 36 connecting the inner ring 34 and the outer ring 35 at a plurality of circumferentially spaced locations, and a plurality of outer protrusions 37 protruding from the axial end of the outer ring 35. The inner ring 34 and the outer ring 35 are formed in a cylindrical shape with the rotation center axis c1 as its axis. The outer ring 35 is formed to have a shorter axial length than the inner ring 34 and is positioned offset from the inner ring 34 in the axial direction. In the following description, for convenience of explanation, the side of the outer ring 35 that is axially offset from the inner ring 34 may be referred to as the "offset side."

[0035] Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 4, Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 4, and Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 4. The connecting wall 36 extends radially outward from one axial end of the inner ring 34 while inclining toward the offset side, and its radially outer end is connected to the outer ring 35. In addition, each outer protrusion 37 protrudes from the axial end of the outer ring 35 on the side opposite the offset side (the end on the side where the inner ring 34 is located). Each outer protrusion 37 protrudes from a position biased radially outward on the end face of the outer ring 35. The radially outer surface of each outer protrusion 37 is formed in an arcuate shape that is flush with the outer peripheral surface of the outer ring 35.

[0036] The outer protrusions 37 are provided on the axial end surface of the outer ring 35 so as to correspond one-to-one with the plurality of connecting walls 36. In other words, the number of outer protrusions 37 provided is the same as the number of connecting walls 36, and each outer protrusion 37 is disposed at a radially outer position of the corresponding connecting wall 36.

[0037] The plurality of balls 32 are arranged annularly along the circumferential direction of the inner ring 34 and the outer ring 35. Each ball 32 is held in the cage 33 so that the spherical center o is located approximately in the center position between the inner circumferential surface of the inner ring 34 and the outer circumferential surface of the outer ring 35. The movement of each ball 32 in the circumferential direction is restricted by a connecting wall 36 and a corresponding outer protrusion 37.

[0038] Openings 38 for slidably holding the balls 32 are formed in the inner ring 34, each of two circumferentially adjacent connecting walls 36, and a portion of the radially inner region of the outer ring 35. The openings 38 slidably hold the balls 32 such that a portion of the balls 32 (a region radially inner than the spherical center o of the outer surface) protrudes radially inward beyond the inner circumferential surface of the inner ring 34. The portion of the ball 32 that protrudes radially inward beyond the inner circumferential surface of the inner ring 34 through the openings 38 abuts against a ball receiving surface 30a (see FIGS. 7 to 9) on the outer peripheral side of the inner ring 30.

[0039] At least a portion of the inner surface 39 of the opening 38 is formed into a concave spherical shape. The radius of this concave spherical surface of the inner surface 39 is set to be approximately the same as the radius of the outer surface of the ball 32. The spherical center of the concave spherical surface of the inner surface 39 is set to approximately coincide with the spherical center o of the ball 32 held in the cage 33.

[0040] The radius of the arc of the inner opening edge 38e of the opening 38 facing the space si radially inside the inner ring 34 (the radius when viewed from the front (viewed from the direction of arrow A in FIG. 9)) is set to be sufficiently smaller than the radius of the outer surface of the ball 32. For this reason, it is not possible to load the ball 32 into the opening 38 from the radial inside of the inner ring 34.

[0041] Furthermore, recesses 40 that slidably hold the balls 32 are formed between every two circumferentially adjacent outer protrusions 37. The recesses 40 slidably hold the balls 32 at radially outer positions of the cage 33 so that portions of the balls 32 (regions radially outer than the spherical center o of the outer surface) protrude radially outward beyond the outer peripheral surface of the outer ring 35. The portions of the balls 32 that protrude radially outward beyond the outer peripheral surface of the outer ring 35 through the recesses 40 abut against ball receiving surfaces 31a (see FIGS. 7 to 9) on the inner peripheral side of the outer ring 31.

[0042] The inner surface 41 (see FIG. 6) of the recess 40 is formed into a concave spherical shape. The radius of the concave spherical surface of the inner surface 41 is set to be approximately the same as the radius of the outer surface of the ball 32. The spherical center of the concave spherical surface of the inner surface 41 is set to be approximately aligned with the spherical center o of the ball 32 held in the cage 33.

[0043] The radius of the arc of the outer opening edge 40e of the recess 40 (when viewed from the front) facing the space so radially outward of the outer ring 35 is set to be larger than the radius of the arc of the inner opening edge 38e (when viewed from the front (when viewed from the direction of arrow B in FIG. 9)). In addition, a circumferential central region of the inner surface 41 of the recess 40 (a middle region between the outer protrusions 37 adjacent in the circumferential direction) is continuous with the concave spherical inner surface 39 of the opening 38.

[0044] In this embodiment, the inner side surface 39 of the opening 38 and the inner side surface 41 of the recess 40 form pockets (holding portions) that slidably hold the balls 32 .

[0045] 7, the connecting wall 36 and the outer protrusions 37 disposed radially outward of the connecting wall 36 are formed to bypass the closest region 50 (see FIG. 3) where adjacent balls 32 are closest to each other in the circumferential direction. Therefore, the opposing apexes of two adjacent balls 32 are closer to each other in the circumferential direction than the thickness of the approximately central region in the radial direction of the connecting wall 36. Therefore, in the cage 33 of this embodiment, the separation width between adjacent balls 32 in the circumferential direction can be sufficiently narrowed.

[0046] Also, as shown in Figure 7, the axial protrusion length L1 of the outer protrusion 37 from the axial end (the end opposite the offset side) of the outer ring 35 is set to be shorter than the axial length L2 from the same axial end to the closest region 50.

[0047] 7, the narrowest circumferential width portion of each connecting wall 36, together with the inner ring 34, the outer ring 35, and the outer protrusion 37, has a generally J-shaped vertical cross section. This can also be said to form cutout portions 46 in the partition walls 45, which are generally trapezoidal when viewed from the circumferential direction, leaving the connecting walls 36 and the outer protrusions 37. In this case, the opening of the cutout portion 46 is a generally U-shaped main opening including the closest regions 50 of adjacent balls 32, connected to an opening extending radially outward from the closest regions 50 (radially crossing the extending ends of the outer protrusions 37). The partition wall 45 holds the ball 32 slidably together with the inner ring 34, with a portion of the ball 32 protruding radially inward from the inner surface of the inner ring 34 and another portion of the ball 32 protruding radially outward from the outer surface of the outer ring 35.

[0048] In the cage 33 of this embodiment, the inner ring 34 and the outer ring 35 are both formed of annular bodies that are continuous in the circumferential direction. In other words, neither the inner ring 34 nor the outer ring 35 has a separation portion in a part of the circumferential direction.

[0049] FIG. 10 is a partially sectional perspective view similar to FIG. 6, showing the state when balls 32 are loaded into cage 33. FIG. 10, the balls 32 are loaded into the cage 33 from the radially outer side of the cage 33. The balls 32 are pressed from the radially outer side toward the radially inner side into the outer opening edge 40e of the recess 40 between two circumferentially adjacent outer protrusions 37 and the outer opening edge of the opening 38 of the inner ring 34.

[0050] At this time, the pushing of the ball 32 causes a portion of the two outer protrusions 37 to bend slightly, and a portion of the ball 32 climbs over the outer opening edges 40e of the two outer protrusions 37. As a result, the ball 32 is received in the concave spherical inner surfaces 41, 39 of the recess 40 and the opening 38, and is prevented from slipping out radially outward by the two outer protrusions 37 that have returned to their original elastic state. As a result, the ball 32 is slidably held on the inner surfaces 39, 41 of the opening 38 and the recess 40, with its slippage prevented by the outer protrusions 37.

[0051] The remaining plurality of balls 32 are similarly loaded into the cage 33 from the radially outer side of the cage 33 .

[0052] <Action and effect> As described above, the cage 33 of this embodiment includes the inner ring 34, the outer ring 35, and a plurality of partition walls 45 that connect the inner ring 34 and the outer ring 35 at multiple circumferentially spaced locations and provide partitions between the plurality of balls 32. The partition walls 45 slidably hold the balls 32 together with the inner ring 34, with some of the balls 32 protruding radially inward from the inner circumferential surface of the inner ring 34 and other parts of the balls 32 protruding radially outward from the outer circumferential surface of the outer ring 35. Each partition wall 45 has a notch 46 that opens from the closest region 50 of adjacent balls 32 toward the radially outer side of the closest region 50. Therefore, adjacent balls 32 can be positioned closer to each other than the thickness of the central region of the partition wall 45. Therefore, the cage 33 of this embodiment can accommodate a larger number of balls 32 in an annular arrangement.

[0053] Furthermore, in the cage 33 of this embodiment, the notch portions 46 of each partition wall 45 open from the closest region 50 toward the radially outer side of the closest region 50, so that the radially outer end portions 45e of each partition wall 45 are connected to the outer ring 35 in a cantilevered manner, and the length of protrusion of the balls 32 in the axial direction from the outer ring 35 is sufficiently short. Therefore, in the case of the cage 33 of this embodiment, when loading the balls 32 from the radially outer side of the outer ring 35, the balls 32 can be easily loaded into the holding portions formed by the inner ring 34 and the two partition walls 45 by simply pushing the balls 32 in and slightly bending the outer ring 35-side end portions of the partition walls 45. In this case, because the radially outer end portions 45e of the partition walls 45 are connected to the outer ring 35 in a cantilevered manner, excessive stress is unlikely to act on the partition walls 45 when the balls 32 are pushed in for loading. Therefore, when the cage 33 of this embodiment is used, the loading efficiency of the balls 32 from the radially outer side can be improved.

[0054] It can also be said that the cage 33 of this embodiment employs the following configuration. The cage 33 includes an inner ring 34 and an outer ring 35, a plurality of connecting walls 36 that connect the inner ring 34 and the outer ring 35 at a plurality of circumferentially spaced locations and that separate the plurality of balls 32, and a plurality of outer protrusions 37 that protrude from the axial end of the outer ring 35 on the inner ring 34 side and that, together with the connecting walls 36, restrict the circumferential movement of the plurality of balls 32. The inner ring 34 and each of two adjacent connecting walls 36 are formed with openings 38 that slidably hold the balls 32 so that a portion of the balls 32 protrudes radially inward beyond the inner circumferential surface of the inner ring 34. Recesses 40 that slidably hold the balls 32 so that another portion of the balls 32 protrudes radially outward beyond the outer circumferential surface of the outer ring 35 are formed between each of two adjacent outer protrusions 37. Each connecting wall 36 and outer protrusion 37 is disposed at a position offset from the closest region 50 of adjacent balls 32. Therefore, adjacent balls 32 can be brought closer to each other by a distance equal to or greater than the thickness of the central region of each connecting wall 36. Therefore, the cage 33 of this embodiment can accommodate a larger number of balls 32 in an annular arrangement.

[0055] Furthermore, in the cage 33, the protrusion length L1 of each outer protrusion 37 from the axial end of the outer ring 35 is set to be shorter than the axial length L2 from that end to the closest region 50. Therefore, each outer protrusion 37 does not protrude significantly from the axial end of the outer ring 35 toward the closest region 50. Therefore, when loading the balls 32 from the radial outside of the outer ring 35, the balls 32 can be easily loaded into the holding portion formed by the openings 38 and recesses 40 by simply pushing the balls 32 in and slightly bending the outer protrusions 37. Therefore, when the cage 33 of this embodiment is used, the loading efficiency of the balls 32 from the radially outer side can be improved.

[0056] In the cage 33 of this embodiment, the openings 38 formed in the inner ring 34 and each of two adjacent connecting walls 36 have arc-shaped inner opening edges 38e facing the space si on the radial inside of the inner ring 34. The recesses 40 between adjacent outer protrusions 37 have arc-shaped outer opening edges 40e facing the space so on the radial outside of the outer ring 35. The arc radius of the outer opening edges 40e is larger than the arc radius of the inner opening edges 38e, and the arc radius of the inner opening edges 38e is set smaller than the radius of the spherical surfaces of the balls 32. In this configuration, the radius of the arc of the outer opening edge 40e of the recess 40 is set to be larger than the radius of the arc of the inner opening edge 38e of the opening 38, so the ball 32 can be easily loaded through the outer opening edge 40e from the radially outside of the outer ring 35. On the other hand, in this configuration, the radius of the arc of the inner opening edge 38e of the opening 38 is set to be smaller than the radius of the spherical surface of the ball 32, so it is difficult to load the ball 32 from the radially inside of the inner ring 34 through the inner opening edge 38e. Therefore, when the retainer 33 of this embodiment is adopted, if the radius of the arc of the inner opening edge 38e of the opening 38 is set to a dimension that can reliably restrict the entry of the ball 32, it is possible to prevent the ball 32 from being forcibly assembled from the wrong direction.

[0057] Furthermore, in the cage 33 of this embodiment, the inner ring 34 and the outer ring 35 are both formed of annular bodies that are continuous in the circumferential direction. Therefore, the two continuous annular bodies, the inner ring 34 and the outer ring 35, can suppress deformation such as parts of the cage separating or twisting. This prevents the cage 33 from changing shape significantly when balls are loaded into the cage 33 or during transportation, making it possible to maintain the cage 33 in a stable shape. Therefore, when the cage 33 of this embodiment is used, the cage 33 can be easily handled when balls are loaded into the cage 33 or during transportation.

[0058] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, although the cage 33 in the above-described embodiment is formed by injection molding, the manufacturing method of the cage 33 is not particularly limited. Furthermore, in the above embodiment, the angular contact ball bearing 12 is applied to the reducer 10, but the application of the angular contact ball bearing 12 is not limited to the reducer 10. The angular contact ball bearing 12 employing the retainer 33 of the embodiment can be applied to various other devices as long as they have a rotating part.

[0059] Furthermore, among the embodiments disclosed in this specification, those that are configured with multiple objects may be integrated, and conversely, those that are configured with a single object may be divided into multiple objects. Regardless of whether they are integrated or not, it is sufficient that they are configured in a way that allows the object of the invention to be achieved. [Explanation of symbols]

[0060] 12...angular contact ball bearing, 32...ball, 33...retainer, 34...inner ring, 35...outer ring, 36...connecting wall, 37...outer protrusion, 38...opening, 38e...inner opening edge, 40...recess, 40e...outer opening edge, 45...partition wall, 46...notch, 50...closest area

Claims

1. Inner ring and an outer ring having an inner diameter larger than an outer diameter of the inner ring and arranged coaxially with the inner ring; a plurality of partition walls that connect the inner ring and the outer ring at a plurality of circumferentially spaced locations and separate the inner ring from a plurality of balls arranged along the outer ring; Equipped with the partition wall slidably holds the ball together with the inner ring in a state in which a portion of the ball protrudes radially inward beyond the inner circumferential surface of the inner ring and another portion of the ball protrudes radially outward beyond the outer circumferential surface of the outer ring, A cage for an angular contact ball bearing, wherein each of the partition walls is provided with a notch that opens from a nearest region where adjacent balls are closest to each other toward the radially outer side of the nearest region.

2. Inner ring and an outer ring having an inner diameter larger than an outer diameter of the inner ring, and arranged coaxially with the inner ring but shifted in the axial direction relative to the inner ring; a plurality of connecting walls that connect the inner ring and the outer ring at a plurality of circumferentially spaced locations and that restrict circumferential movement of each of a plurality of balls arranged along the circumferential direction of the inner ring and the outer ring; a plurality of outer protrusions provided on an axial end of the outer ring on the inner ring side and configured to restrict circumferential movement of each of the plurality of balls together with the connecting wall, At least the inner ring and each of the two connecting walls adjacent in the circumferential direction are formed with openings for slidably holding the balls such that portions of the balls protrude radially inward beyond the inner circumferential surface of the inner ring, Between each pair of the outer protrusions adjacent in the circumferential direction, a recess is formed to slidably hold the ball so that another portion of the ball protrudes radially outward beyond the outer peripheral surface of the outer ring, the connecting wall and the outer protrusion are disposed at positions shifted from a closest region where the adjacent balls are closest to each other, A retainer for an angular contact ball bearing, wherein the protruding length of each outer protrusion from the axial end of the outer ring is set shorter than the axial length from the end to the closest region.

3. the opening has an arc-shaped inner opening edge at a portion facing a space radially inside the inner ring, the recess has an arc-shaped outer opening edge at a portion facing a space radially outward of the outer ring, The radius of the arc of the outer opening edge is set to be larger than the radius of the arc of the inner opening edge, 3. The cage for an angular contact ball bearing according to claim 2, wherein the radius of the arc of the inner opening edge is set smaller than the radius of the spherical surface of the ball.

4. 4. The cage for an angular contact ball bearing according to claim 1, wherein the inner ring and the outer ring are both formed of an annular body that is continuous in the circumferential direction.

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