Self-aligning ball bearing

Abstract

A self-aligning ball bearing having a self-aligning property has a structure that can reduce the axial width dimension. [Solution] The self-aligning ball bearing 1 comprises an outer ring 2 having an outer ring raceway 5 on its inner peripheral surface formed by a spherical concave surface centered on the bearing center, an inner ring 3 having an inner ring raceway 7 on its outer peripheral surface facing the outer ring raceway 5, and a plurality of balls 4a, 4b arranged between the outer ring raceway 5 and the inner ring raceway 7. The plurality of balls 4a, 4b includes a plurality of first balls 4a whose centers C1 are arranged at a first axial position, and a plurality of second balls 4b whose centers C2 are arranged at a second axial position different from the first axial position, and the axial distance between the first axial position and the second axial position is equal to or less than the ball diameters of the plurality of balls 4a, 4b.

Description

[Technical Field]

[0001] The present disclosure relates to self-aligning ball bearings. [Background technology]

[0002] 7 shows a conventional self-aligning ball bearing 100 described in Japanese Patent Application Laid-Open No. 2010-121649. This self-aligning ball bearing 100 includes an outer ring 101, an inner ring 102, and a plurality of balls 103a and 103b.

[0003] The outer ring 101 has, on its inner peripheral surface, an outer ring raceway 104 formed by a partial spherical concave surface centered on the bearing center.

[0004] The inner ring 102 has double-row inner ring raceways 105 a and 105 b on the outer peripheral surface thereof, in a portion facing the outer ring raceway 104 .

[0005] A plurality of balls 103a, 103b are arranged between an outer ring raceway 104 and double row inner ring raceways 105a, 105b, with multiple balls in each row, and are held by a cage 106 so that they can roll freely.

[0006] The cage 106 has an annular rim portion 107, and a plurality of pillar portions 108a extending toward one axial side from multiple circumferential positions on the radially outer end of the rim portion 107, and a plurality of pillar portions 108b extending toward the other axial side from multiple circumferential positions on the radially outer end of the rim portion 107. The pillar portions 108a on one axial side extending toward one axial side from the radially outer end of the rim portion 107 and the pillar portions 108b on the other axial side extending toward the other axial side from the radially outer end of the rim portion 107 are arranged alternately in the circumferential direction. The portion surrounded on three sides by a pair of circumferentially adjacent pillar portions 108a on one axial side and rim portion 107 is pocket 109a for holding ball 103a on one axial side, and the portion surrounded on three sides by a pair of circumferentially adjacent pillar portions 108b on the other axial side and rim portion 107 is pocket 109b for holding ball 103b on the other axial side.

[0007] In self-aligning ball bearing 100, outer ring raceway 104 is configured as a partial spherical concave surface centered on the bearing center, so inner ring 102, balls 103a, 103b, and cage 106 are able to oscillate about an axis that is perpendicular to the central axis of outer ring 101 and passes through the bearing center. For this reason, self-aligning ball bearing 100 can be used in rotation support parts where aligning the rotating shaft with the housing is difficult, and in rotation support parts that rotatably support a transmission shaft, which is prone to flexural deformation, relative to the housing. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-121649 Summary of the Invention [Problem to be solved by the invention]

[0009] In the self-aligning ball bearing 100 described in JP 2010-121649 A, the axial distance between the center of ball 103a on one axial side and the center of ball 103b on the other axial side is approximately equal to or larger than the ball diameter of balls 103a and 103b, resulting in a large axial width dimension.

[0010] An object of the present disclosure is to realize a structure that allows the axial width dimension to be kept small in a self-aligning ball bearing having self-aligning properties. [Means for solving the problem]

[0011] A self-aligning ball bearing according to one aspect of the present disclosure includes an outer ring, an inner ring, and a plurality of balls.

[0012] The outer ring has an outer ring raceway on its inner peripheral surface, which is formed by a partially spherical concave surface centered on the bearing center.

[0013] The inner ring has an inner ring raceway on its outer peripheral surface that faces the outer ring raceway.

[0014] The plurality of balls are arranged between the outer ring raceway and the inner ring raceway, and include a plurality of first balls whose centers are arranged at a first axial position, and a plurality of second balls whose centers are arranged at a second axial position different from the first axial position.

[0015] In particular, in a self-aligning ball bearing according to one aspect of the present disclosure, the axial distance between the first axial position and the second axial position is equal to or less than the ball diameter of the plurality of balls.

[0016] In a self-aligning ball bearing according to one embodiment of the present disclosure, the axial distance is preferably less than the ball diameter of the plurality of balls, more preferably 20% to 70% of the ball diameter of the plurality of balls, and even more preferably 35% to 50% of the ball diameter of the plurality of balls.

[0017] In the self-aligning ball bearing according to one aspect of the present disclosure, the plurality of first balls and the plurality of second balls can be arranged alternately one by one in the circumferential direction.

[0018] Alternatively, the plurality of first balls and the plurality of second balls may be arranged alternately in groups of two or more in the circumferential direction. Alternatively, the plurality of first balls and the plurality of second balls may be arranged in no particular order.

[0019] A self-aligning ball bearing according to one embodiment of the present disclosure may further include a retainer having a plurality of first pockets that hold the plurality of first balls in a rollable manner, and a plurality of second pockets that hold the plurality of second balls in a rollable manner.

[0020] In this case, the cage may have a first cage element and a second cage element, each of which is an annular pressed product.

[0021] The first retainer element can have a flat first base plate portion, first large curved plate portions having a partial spherical shell shape arranged at multiple locations in the circumferential direction, and first small curved plate portions having a partial spherical shell shape arranged at multiple locations in the circumferential direction and having a smaller protrusion from the first base plate portion than the first large curved plate portions.

[0022] The second retainer element can have a flat second base plate portion, second large curved plate portions having a partial spherical shell shape arranged at multiple locations in the circumferential direction, and first small curved plate portions having a partial spherical shell shape arranged at multiple locations in the circumferential direction and having a smaller protrusion from the second base plate portion than the second large curved plate portions.

[0023] The holder can be configured by joining and fixing the first holder element and the second holder element in a state in which the first substrate portion and the second substrate portion are superimposed on each other.

[0024] Each of the plurality of first pockets can be formed by a portion surrounded by the first large curved plate portion and the second small curved plate portion, and each of the plurality of second pockets can be formed by a portion surrounded by the second large curved plate portion and the first small curved plate portion.

[0025] In a self-aligning ball bearing according to one embodiment of the present disclosure, the elastic force of the retainer can be used to impart elastic force to the plurality of first balls and the plurality of second balls in a direction that moves them away from each other in the axial direction.

[0026] Alternatively, in a self-aligning ball bearing according to one embodiment of the present disclosure, preload can be applied to the plurality of first balls and the plurality of second balls by applying elastic force using a method other than a method based on the elasticity of the retainer, or no preload can be applied.

[0027] In a self-aligning ball bearing according to one embodiment of the present disclosure, the inner ring raceway can include two concave curved surface portions arranged on both axial sides and having an arc-shaped generatrix shape, and a connecting surface portion arranged in the middle of the axial direction and connecting the two concave curved surface portions.

[0028] In this case, the connection surface portion can be configured as a cylindrical surface whose outer diameter does not change in the axial direction.

[0029] Alternatively, the connecting surface portion may have two connecting concave curved surface portions each curved in a direction such that the outer diameter becomes smaller from the axial center portion toward the axial outside. [Effects of the Invention]

[0030] According to the present disclosure, the axial width dimension of a self-aligning ball bearing having self-aligning properties can be kept small. [Brief explanation of the drawings]

[0031] [Figure 1] Figure 1(A) is a half cross-sectional view of a self-aligning ball bearing according to a first example of an embodiment of the present disclosure, taken along an imaginary plane including the center axis and the center of the first ball, and Figure 1(B) is a half cross-sectional view of a self-aligning ball bearing according to the first example, taken along an imaginary plane including the center axis and the center of the second ball. [Figure 2] FIG. 2 is a view showing the inner ring taken out from the self-aligning ball bearing according to the first example. [Figure 3] FIG. 3 is a cross-sectional view showing a cage taken out from a self-aligning ball bearing according to the first example. [Figure 4] FIG. 4 is a view corresponding to FIG. 2 of a self-aligning ball bearing according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram schematically illustrating an electric power steering device incorporating a self-aligning ball bearing according to a third embodiment of the present disclosure. [Figure 6] FIG. 6 is a cross-sectional view showing a steering gear unit of an electric power steering device according to a third example. [Figure 7] FIG. 7 is a partially cutaway perspective view showing a conventional self-aligning ball bearing. DETAILED DESCRIPTION OF THE INVENTION

[0032] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. FIG.

[0033] In the following description, unless otherwise specified, the axial, radial, and circumferential directions of the self-aligning ball bearing 1 refer to the axial, radial, and circumferential directions of the outer ring 2. In a neutral state in which the central axes of the outer ring 2 and the inner ring 3 are aligned, the axial, radial, and circumferential directions of the outer ring 2 coincide with the axial, radial, and circumferential directions of the inner ring 3. Furthermore, the outer axial direction refers to both sides in the left-right direction in Figures 1 to 3, and the inner axial direction refers to the center side in the left-right direction in Figures 1 to 3. Furthermore, one axial side refers to the left side in Figures 1 to 3, and the other axial side refers to the right side in Figures 1 to 3.

[0034] The self-aligning ball bearing 1 is incorporated into the rotational support parts of various mechanical devices. For example, but not limited to, the self-aligning ball bearing 1 can be used as a bearing for rotatably supporting the pinion shaft of a rack-and-pinion gear unit relative to a housing, or as a bearing for rotatably supporting a roll in a paper-making machine.

[0035] The self-aligning ball bearing 1 comprises an outer ring 2, an inner ring 3, and a plurality of balls 4a, 4b.

[0036] The outer ring 2 has, on its inner peripheral surface, an outer ring raceway 5 formed by a partially spherical concave surface centered on the bearing center O. In other words, the outer ring raceway 5 has a generatrix shape of a single arc centered on the bearing center O.

[0037] The outer ring 2 is made of hard metal such as medium carbon steel or high carbon chromium bearing steel, and is configured in an annular shape as a whole.

[0038] The inner ring 3 has an inner ring raceway 6 facing the outer ring raceway 5 on its outer peripheral surface.

[0039] The inner ring raceway 6 is provided with two concave curved surface portions 7a, 7b arranged on both sides in the axial direction and having an arc-shaped generatrix shape, and a connecting surface portion 8 arranged in the middle in the axial direction and connecting the two concave curved surface portions 7a, 7b together.

[0040] Each of the concavely curved surface portions 7a, 7b is configured with a concavely curved surface having an arc-shaped generatrix whose outer diameter increases axially outward. The generatrix of each of the concavely curved surface portions 7a, 7b has a radius of curvature slightly larger than half the diameter of the balls 4a, 4b, and is configured with an arc that curves radially outward as it extends axially outward. Therefore, the inner ring 3 has groove shoulders 60a, 60b that protrude radially outward at both axially outer ends.

[0041] In a cross section relative to an imaginary plane including the center axis of the inner ring 3, the center of curvature C of the concave curved surface portion 7a on one axial side of the two concave curved surface portions 7a, 7b A is approximately coincident with the center C1 of the first ball 4a and is also coincident with the center of curvature C of the concave curved surface portion 7b on the other axial side. B substantially coincides with the center C2 of the second ball 4b.

[0042] The connecting surface portion 8 connects the axially inner ends (proximal ends) of the two concave curved surface portions 7a, 7b together.

[0043] The connection surface portion 8 can be configured as a cylindrical surface whose outer diameter does not change in the axial direction.

[0044] Alternatively, the connecting surface portion 8 can have two connecting concave curved surface portions, each curved in a direction such that the outer diameter decreases from the axial center toward the axial outward. In this case, of the two connecting concave curved surface portions, the connecting concave curved surface portion on one axial side has the same radius of curvature as the concave curved surface portion on one axial side and the same center of curvature as the concave curved surface portion on one axial side. Furthermore, the connecting concave curved surface portion on the other axial side has the same radius of curvature as the concave curved surface portion on the other axial side and the same center of curvature as the concave curved surface portion on the other axial side. In other words, the generatrix of the concave curved surface portion on one axial side and the generatrix of the connecting concave curved surface portion on one axial side lie on the same arc, and the generatrix of the concave curved surface portion on the other axial side and the generatrix of the connecting concave curved surface portion on the other axial side also lie on the same arc.

[0045] In this example, the connection surface portion 8 is formed of a cylindrical surface whose outer diameter does not change in the axial direction. That is, the generatrix of the connection surface portion 8 is formed by a straight line parallel to the center axis of the inner ring 3. Both axial ends of the connection surface portion 8 are smoothly connected to the axially inner ends of the two concave curved surface portions 7a, 7b. Therefore, in this example, the inner ring raceway 6 has a generatrix shape that is approximately U-shaped (approximately bathtub curved).

[0046] In this example, the connecting surface portion 8 that connects the two concavely curved surface portions 7a, 7b is configured with a cylindrical surface, and the shape of the inner ring raceway 6 is simple, which facilitates the processing of the inner ring 3. As a result, the manufacturing costs of the self-aligning ball bearing 1 can be reduced.

[0047] A plurality of balls 4 a, 4 b are arranged between an outer ring raceway 5 and an inner ring raceway 6 so as to be able to roll freely.

[0048] The plurality of balls 4a, 4b includes a plurality of first balls 4a whose centers C1 are located in a first axial position and a plurality of second balls 4b whose centers C2 are located in a second axial position different from the first axial position. In other words, the centers C1 of the plurality of first balls 4a are located on a first imaginary plane perpendicular to the central axis of the outer ring 2, and the centers C2 of the plurality of second balls 4b are located on a second imaginary plane parallel to the first imaginary plane. In this example, the radial positions of the centers C1 of the plurality of first balls 4a and the radial positions of the centers C2 of the plurality of second balls 4b are the same. In other words, the pitch circle diameters of the plurality of first balls 4a and the plurality of second balls 4b are the same.

[0049] The diameter of the first ball 4a and the diameter of the second ball 4b are the same, that is, the plurality of balls 4a, 4b all have the same diameter.

[0050] The plurality of first balls 4a are capable of bringing their respective rolling surfaces into rolling contact with the outer ring raceway 5 and the concavely curved surface portion 7a on one axial side of the inner ring raceway 6, depending on the direction of the elastic force imparted by the elasticity of the cage 9 and the direction of the load acting on the self-aligning ball bearing 1. The plurality of second balls 4b are capable of bringing their respective rolling surfaces into rolling contact with the outer ring raceway 5 and the concavely curved surface portion 7b on the other axial side of the inner ring raceway 6, depending on the direction of the elastic force imparted by the elasticity of the cage 9 and the direction of the load acting on the self-aligning ball bearing 1. As a result, the line of load action of the first balls 4a inclines radially inward as it moves from one axial side to the other axial side and passes through the bearing center O, whereas the line of load action of the second balls 4b inclines radially inward as it moves from the other axial side to one axial side and passes through or approaches the bearing center O.

[0051] The axial distance L between the first axial direction position and the second axial direction position is not more than the ball diameter D of the plurality of balls 4a and 4b (L≦D). Although the axial distance L is not limited to this, it is preferably less than the ball diameter D (L<D), more preferably 20% or more and 70% or less of the ball diameter D (0.2D≦L≦0.7D), and still more preferably 35% or more and 50% or less of the ball diameter D (0.35D≦L≦0.5D). In this example, the axial distance L is about 50% of the ball diameter D.

[0052] The number of the first balls 4a and the number of the second balls 4b can be the same as each other or different from each other. However, from the aspect of evenly distributing the load acting on the self-aligning ball bearing 1 between the plurality of first balls 4a and the plurality of second balls 4b, it is preferable that the number of the first balls 4a and the number of the second balls 4b be the same as each other.

[0053] The arrangement order of the plurality of first balls 4a and the plurality of second balls 4b is not particularly limited. For example, the plurality of first balls 4a and the plurality of second balls 4b can be arranged alternately one by one in the circumferential direction, can be arranged alternately in plural numbers, or can be arranged in any order. However, from the aspect of evenly distributing the load acting on the self-aligning ball bearing 1 between the plurality of first balls 4a and the plurality of second balls 4b, it is preferable that the plurality of first balls 4a and the plurality of second balls 4b be arranged alternately one by one in the circumferential direction.

[0054] In this example, the number of the first balls 4a and the number of the second balls 4b are the same as each other, and the plurality of first balls 4a and the plurality of second balls 4b are arranged alternately one by one and at equal intervals in the circumferential direction.

[0055] In the self-aligning ball bearing 1 of this example, since the outer ring raceway 5 provided on the inner peripheral surface of the outer ring 2 is constituted by a partial spherical concave surface centered on the bearing center O, the inner ring 3 and the balls 4a, 4b can swing about an axis that is orthogonal to the central axis of the outer ring 2 and passes through the bearing center O. Therefore, in the self-aligning ball bearing 1 of this example, even when the central axis of the inner ring 3 is inclined with respect to the central axis of the outer ring 2, the rolling of the balls 4a, 4b between the outer ring raceway 5 and the inner ring raceway 6 can be smoothly performed. That is, the self-aligning ball bearing 1 of this example has self-aligning ability.

[0056] Also, in the self-aligning ball bearing 1 of this example, the first axial position where the center C1 of the first ball 4a is located and the second axial position where the center C2 of the second ball 4b is located are different from each other. Therefore, according to the self-aligning ball bearing 1 of this example, it is easier to secure an allowable amount of inclination of the inner ring 3 with respect to the outer ring 2 compared to a single-row ball bearing.

[0057] Furthermore, in the self-aligning ball bearing 1 of this example, the axial distance L between the first axial position and the second axial position is equal to or less than the ball diameter D of the plurality of balls 4a, 4b (L ≤ D), preferably less than the ball diameter D (L < D). Therefore, according to the self-aligning ball bearing 1 of this example, compared to the self-aligning ball bearing 100 described in Japanese Patent Application Laid-Open No. 2010-121649, the axial width dimension can be suppressed to be small. For this reason, the degree of freedom in the design of the mechanical device in which the self-aligning ball bearing 1 is incorporated can be ensured well.

[0058] As an optional component, the self-aligning ball bearing 1 further includes a cage 9 that holds a plurality of balls 4a, 4b so as to be rotatable. The cage 9 has a plurality of first pockets 10a that hold a plurality of first balls 4a so as to be rotatable and a plurality of second pockets 10b that hold a plurality of second balls 4b so as to be rotatable.

[0059] The arrangement order of the first pockets 10a and the second pockets 10b is determined according to the arrangement order of the first balls 4a and the second balls 4b. In this example, the first balls 4a and the second balls 4b are arranged alternately one by one in the circumferential direction, and therefore the first pockets 10a and the second pockets 10b are arranged alternately one by one in the circumferential direction.

[0060] When implementing a self-aligning ball bearing according to one embodiment of the present disclosure, a cage such as a wave cage, a crown cage, a machined cage, or a cage type cage can be used as the cage 9. In this example, the cage 9 is constituted by a wave cage.

[0061] Specifically, the cage 9 has a first cage element 11a and a second cage element 11b, each of which is an annular pressed product. More specifically, the first cage element 11a and the second cage element 11b are each formed into a corrugated annular shape by punching and bending a steel plate using a press.

[0062] The first cage element 11a has a first base plate portion 12a, a plurality of first large curved plate portions 13a, and a plurality of first small curved plate portions 14a.

[0063] The first substrate portion 12a is configured in a flat plate shape.

[0064] In this example, the first substrate portion 12a has a plurality of first substrate pieces 15a each configured as a flat plate. The plurality of first substrate pieces 15a are arranged at the same axial position. Both axial side surfaces of the first substrate pieces 15a are configured as flat surfaces that are approximately perpendicular to the central axis of the cage 9.

[0065] The first base plate pieces 15a have an end face shape that is generally arc-shaped when viewed in the axial direction, and are arranged at multiple locations in the circumferential direction of the first cage element 11a. Specifically, each of the first base plate pieces 15a is arranged between the first large curved plate portion 13a and the first small curved plate portion 14a that are adjacent to each other in the circumferential direction.

[0066] The first large curved plate portions 13a are arranged at a plurality of positions in the circumferential direction of the first cage element 11a and are configured in the shape of a partial spherical shell. In this example, the first large curved plate portions 13a are configured in the shape of a curved band.

[0067] The first large curved plate portion 13a curves in a direction toward the other axial side from the circumferential center toward both circumferential sides, and curves in a direction toward the other axial side from the radial center toward both radial sides. That is, the side surface on the other axial side of the first large curved plate portion 13a is configured as a partially spherical concave surface, and the side surface on one axial side of the first large curved plate portion 13a is configured as a partially spherical convex surface. The side surface on the other axial side of the first large curved plate portion 13a forms one axial side portion of the inner surface of the first pocket 10a, and has a radius of curvature slightly larger than half the diameter of the first ball 4a.

[0068] The first large curved plate portion 13a has a central angle θ L1 The first large curved plate portion 13a has an end face shape in the shape of a circular arc, the central angle θ of which is greater than 180 degrees when viewed from the radial direction. L1 Although not limited to this, the central angle θ of the first large curved plate portion 13a can be set to 200 degrees or more and 250 degrees or less, and is preferably set to 215 degrees or more and 235 degrees or less. L1 is about 240 degrees.

[0069] The first small curved plate portions 14a are arranged at multiple locations in the circumferential direction of the first cage element 11a and are configured in the shape of a partial spherical shell with a smaller protrusion from the first base plate portion 12a than the first large curved plate portion 13a. In this example, the first small curved plate portions 14a are configured in the shape of a curved band.

[0070] Specifically, the first small curved plate portion 14a curves more in the direction toward the other axial side from the circumferential center toward both circumferential sides, and also curves more in the direction toward the other axial side from the radial center toward both radial sides. That is, the side surface on the other axial side of the first small curved plate portion 14a is configured as a partially spherical concave surface, and the side surface on one axial side of the first small curved plate portion 14a is configured as a partially spherical convex surface. The side surface on the other axial side of the first small curved plate portion 14a forms one axial side portion of the inner surface of the second pocket 10b, and has a radius of curvature slightly larger than half the diameter of the second ball 4b.

[0071] The first small curved plate portion 14a has a central angle θ S1 The central angle θ of the first small curved plate portion 14a when viewed from the radial direction is smaller than 180 degrees. S1 Although not limited to this, the central angle θ of the first small curved plate portion 14a can be set to 110 degrees or more and 160 degrees or less, and is preferably set to 125 degrees or more and 145 degrees or less. S1 is about 120 degrees.

[0072] The second cage element 11b has a second base plate portion 12b, a plurality of second large curved plate portions 13b, and a plurality of second small curved plate portions 14b.

[0073] The second substrate portion 12b is configured in a flat plate shape.

[0074] In this example, the second substrate portion 12b has a plurality of second substrate pieces 15b each configured as a flat plate. The plurality of second substrate pieces 15b are arranged at the same axial position. Both axial side surfaces of the second substrate pieces 15b are each configured as a flat surface that is approximately perpendicular to the central axis of the retainer 9.

[0075] The second base plate pieces 15b have an end face shape that is generally arc-shaped when viewed in the axial direction, and are arranged at multiple locations in the circumferential direction of the second cage element 11b. Specifically, each second base plate piece 15b is arranged between the second large curved plate portion 13b and the second small curved plate portion 14b that are adjacent in the circumferential direction.

[0076] The second large curved plate portions 13b are arranged at a plurality of positions in the circumferential direction of the second cage element 11b and are configured in the shape of a partial spherical shell. In this example, the second large curved plate portions 13b are configured in the shape of a curved band.

[0077] Specifically, the second large curved plate portion 13b curves more toward one axial side from the circumferential center toward both circumferential sides, and also curves more toward one axial side from the radial center toward both radial sides. That is, the side surface on one axial side of the second large curved plate portion 13b is configured as a partially spherical concave surface, and the side surface on the other axial side of the second large curved plate portion 13b is configured as a partially spherical convex surface. The side surface on one axial side of the second large curved plate portion 13b forms the other axial side portion of the inner surface of the second pocket 10b and has a radius of curvature slightly larger than half the diameter of the second ball 4b.

[0078] The second large curved plate portion 13b has a central angle θ L2 The second large curved plate portion 13b has an end face shape in the shape of a circular arc, with a central angle θ of greater than 180 degrees when viewed from the radial direction. L2 Although not limited to this, the central angle θ of the second large curved plate portion 13b can be set to 200 degrees or more and 250 degrees or less, and is preferably set to 215 degrees or more and 235 degrees or less. L2 is about 240 degrees.

[0079] The second small curved plate portions 14b are arranged at multiple locations in the circumferential direction of the second cage element 11b, and are configured in the shape of a partial spherical shell that protrudes less from the second base plate portion 12b than the second large curved plate portion 13b. In this example, the second small curved plate portions 14b are configured in the shape of a curved band.

[0080] The second small curved plate portion 14b curves in a direction toward one axial side from the circumferential center toward both circumferential sides, and also curves in a direction toward one axial side from the radial center toward both radial sides. That is, the side surface on one axial side of the second small curved plate portion 14b is configured as a partially spherical concave surface, and the side surface on the other axial side of the second small curved plate portion 14b is configured as a partially spherical convex surface. The side surface on one axial side of the second small curved plate portion 14b forms the other axial side portion of the inner surface of the second pocket 10b, and has a radius of curvature slightly larger than half the diameter of the second ball 4b.

[0081] The second small curved plate portion 14b has a central angle θ S2 The central angle θ of the second small curved plate portion 14b when viewed from the radial direction is smaller than 180 degrees. S2 Although not limited to this, the central angle θ of the second small curved plate portion 14b can be set to 110 degrees or more and 160 degrees or less, and is preferably set to 125 degrees or more and 145 degrees or less. S2 is about 120 degrees.

[0082] The cage 13 is formed by connecting and fixing the first cage element 11a and the second cage element 11b in a state in which the first substrate portion 12a and the second substrate portion 12b are overlapped. The method for connecting the first cage element 11a and the second cage element 11b is not particularly limited. For example, the first cage element 11a and the second cage element 11b can be connected and fixed using connecting members such as rivets 16, bolts, and nuts, or can be connected and fixed by welding the overlapping portion of the first substrate portion 12a and the second substrate portion 12b.

[0083] In this example, the first cage element 11a and the second cage element 11b are joined and fixed by a plurality of rivets 16. Specifically, a rod portion 18 of the rivet 16 is inserted into first through-holes 17a provided at a plurality of locations in the circumferential direction of the first base plate portion 12a and second through-holes 17b provided at a plurality of locations in the circumferential direction of the second base plate portion 12b, and the tip end of the rod portion 18 is crushed to form a crimped portion 19. As a result, the first base plate portion 12a and the second base plate portion 12b are sandwiched between the head 20 of the rivet 16 and the crimped portion 19, thereby joining and fixing the first cage element 11a and the second cage element 11b.

[0084] The first cage element 11a and the second cage element 11b can be configured using the same parts (common parts) of the same shape and size, or they can be configured using different parts. In this example, the first cage element 11a and the second cage element 11b are configured using the same parts. Specifically, the cage 13 is configured by connecting and fixing the first cage element 11a and the second cage element 11b, which are the same parts, in a state where they are arranged with their phases shifted from each other in the circumferential direction. Therefore, with the self-aligning ball bearing 1 of this example, costs can be reduced by sharing parts, and the number of assembly steps can be reduced.

[0085] Each of the multiple first pockets 10a is formed by a portion surrounded by a first large curved plate portion 13a and a second small curved plate portion 14b, and each of the multiple second pockets 10b is formed by a portion surrounded by a second large curved plate portion 13b and a first small curved plate portion 14a.

[0086] In the self-aligning ball bearing 1 of this example, when an axial load is applied between the outer ring 2 and the inner ring 3 and the multiple balls 4a, 4b attempt to move toward one axial direction, the movement of the first ball 4a toward that side is primarily restricted by the rolling surface of the first ball 4a coming into contact with the concave curved surface portion 7a on that side of the axial direction. In other words, the movement of the first ball 4a toward that side of the axial direction is primarily restricted by the groove shoulder 60a provided at the end of the inner ring 3 on that side of the axial direction. In contrast, the movement of the second ball 4b toward that side of the axial direction is primarily restricted by the rolling surface of the second ball 4b coming into contact with the portion of the inner surface of the second pocket 10b on that side of the axial direction. The movement of the cage 9 toward that side of the axial direction is primarily restricted by the rolling surface of the first ball 4a coming into contact with the portion of the inner surface of the first pocket 10a on the other axial direction.

[0087] Conversely, when an axial load is applied between the outer ring 2 and the inner ring 3, causing the multiple balls 4a, 4b to move toward the other axial direction, the movement of the first ball 4a toward the other axial direction is restricted mainly by the rolling surface of the first ball 4a coming into contact with the other axial side portion of the inner surface of the first pocket 10a. In contrast, the movement of the second ball 4b toward the other axial direction is restricted mainly by the rolling surface of the second ball 4b coming into contact with the concave curved surface 7b on the other axial side. In other words, the movement of the second ball 4b toward the other axial direction is restricted mainly by the groove shoulder 60b provided at the end of the inner ring 3 on the other axial side. The movement of the cage 9 toward the other axial direction is restricted by the one axial side portion of the inner surface of the second pocket 10b coming into contact with the rolling surface of the second ball 4b.

[0088] That is, in the self-aligning ball bearing 1 of this example, the axial movement of one of the first balls 4a and the second balls 4b is restricted by the concave curved surface portion 7a (or 7b) provided on the inner ring 3, and the axial movement of the other ball is restricted by the inner ring 3 via the cage 9 and one of the balls. Therefore, with the self-aligning ball bearing 1 of this example, there is no need to make the shape accuracy and dimensional accuracy of the inner ring raceway 6 excessively high, and the manufacturing costs of the inner ring 3 can be reduced.

[0089] In contrast, when the axial movement of balls 103a, 103b arranged in double rows is restricted by double row inner ring raceways 105a, 105b provided on inner ring 102, as in the self-aligning ball bearing 100 described in JP 2010-121649 A, the double row inner ring raceways 105a, 105b must be formed with high precision, which may increase the manufacturing costs of inner ring 102.

[0090] Furthermore, in the self-aligning ball bearing 1 of this example, the retainer 9 is configured to apply, based on its elasticity, an elastic force to the plurality of first balls 4a and the plurality of second balls 4b in a direction that moves them away from each other in the axial direction.

[0091] For this purpose, specifically, in a free state before the cage 9 holding the plurality of balls 4a, 4b is assembled between the outer ring 2 and the inner ring 3, the axial distance L between the center P1 of the first pocket 10a and the center P2 of the second pocket 10b is 10 is the center of curvature C of the concave curved surface portion 7a on one axial side in a cross section including the center axis of the inner ring 3. A and the center of curvature C of the concave curved surface portion 7b on the other axial side B The distance L2 between the shaft 1 and the shaft 2 is set to be larger than the axial distance L7 between the shaft 1 and the shaft 2, or is set to be approximately the same as the axial distance L7.

[0092] For this reason, the cage 9 holds the plurality of balls 4a, 4b in the plurality of pockets 10a, 10b, and, when assembled between the outer ring 2 and the inner ring 3, the first pockets 10a and the second pockets 10b are elastically deformed in a direction in which they approach each other. Therefore, the force of the cage 9 attempting to elastically restore its original shape elastically presses the plurality of first balls 4a and the plurality of second balls 4b in directions in which they move away from each other in the axial direction.

[0093] In this example, the elasticity of cage 9 is used to impart an elastic force to the first balls 4a and the second balls 4b in directions that move them away from each other in the axial direction, thereby substantially eliminating any internal gap in the axial direction of self-aligning ball bearing 1. As a result, rattle of self-aligning ball bearing 1 can be suppressed.

[0094] However, when implementing a self-aligning ball bearing according to one aspect of the present disclosure, a preload can be applied to the plurality of first balls and the plurality of second balls by applying elastic force using a method other than a method based on the elasticity of the cage, or no preload can be applied. Specifically, for example, when the self-aligning ball bearing is incorporated into a mechanical device, concentricity between the outer ring and the inner ring can be sufficiently ensured, and before the mechanical device starts operating, if no axial load acts between the outer ring and the inner ring, no preload can be applied to the plurality of first balls and the plurality of second balls.

[0095] [Example 2] A second example of the embodiment of the present disclosure will be described with reference to FIG.

[0096] In this example, the shape of the inner ring raceway 6a of the inner ring 3a is changed from the shape of the inner ring raceway 6 of the inner ring 3 in the first example. More specifically, the shape of the connecting surface portion 8a of the inner ring raceway 6a that connects the two concavely curved surface portions 7a, 7b together is changed from the shape of the connecting surface portion 8 in the first example.

[0097] In this example, connecting surface portion 8a has two connecting concave curved surface portions 21a, 21b, each curved in a direction such that the outer diameter decreases from the axial center toward the axial outside. In other words, inner ring 3a has a central groove shoulder 61 with a generally triangular cross section, between two concave curved surface portions 7a, 7b, and provided with two connecting concave curved surface portions 21a, 21b on its outer peripheral surface.

[0098] Of the two connecting concave curved surface portions 21a, 21b, the connecting concave curved surface portion 21a on one axial side has the same radius of curvature as the radius of curvature of the concave curved surface portion 7a on one axial side, and the center of curvature C of the concave curved surface portion 7a on one axial side A The connecting concave curved surface portion 21b on the other axial side has the same radius of curvature as the concave curved surface portion 7b on the other axial side, and the radius of curvature of the concave curved surface portion 7b on the other axial side is equal to the radius of curvature of the concave curved surface portion 7b on the other axial side. BThat is, the generatrix of the concave curved surface portion 7a on one axial side and the generatrix of the connecting concave curved surface portion 21a on one axial side are on the same arc, and the generatrix of the concave curved surface portion 7b on the other axial side and the generatrix of the connecting concave curved surface portion 21b on the other axial side are on the same arc.

[0099] In this example, when an axial load is applied between the outer ring 2 and the inner ring 3a and the multiple balls 4a, 4b attempt to move axially to one side, the movement of the first ball 4a to one side is restricted mainly by the rolling surface of the first ball 4a coming into contact with the concave curved surface portion 7a on one axial side. In contrast, the movement of the second ball 4b to one side is restricted mainly by the rolling surface of the second ball 4b coming into contact with the connecting concave curved surface portion 21b on the other axial side. In other words, the movement of the first ball 4a to one side in the axial direction is restricted mainly by the groove shoulder 60a provided at the end of one axial side of the inner ring 3, and the movement of the second ball 4b to one side in the axial direction is restricted mainly by the central groove shoulder 61.

[0100] Conversely, when the multiple balls 4a, 4b attempt to move toward the other axial direction, movement of the first ball 4a toward the other axial direction is restricted mainly by the rolling surface of the first ball 4a coming into contact with the connecting concave curved surface portion 21a on one axial side. In contrast, movement of the second ball 4b toward the other axial direction is restricted by the rolling surface of the second ball 4b coming into contact with the one axial side portion of the inner surface of the concave curved surface portion 7b on the other axial side. In other words, movement of the first ball 4a toward the other axial direction is restricted mainly by the central groove shoulder 61, and movement of the second ball 4b toward the other axial direction is restricted mainly by the groove shoulder 60b provided at the end of the inner ring 3 on the other axial side.

[0101] According to this example, the axial load applied to the cage 9 can be kept small, and the strength and rigidity required for the cage 9 can be kept small.

[0102] The configuration and effects of other parts of the second example are the same as those of the first example.

[0103] [Example 3] A third example of the embodiment of the present disclosure will be described with reference to FIGS.

[0104] In this example, a self-aligning ball bearing according to one aspect of the present disclosure is applied to a bearing that supports a pinion shaft 31 of a rack-and-pinion steering gear unit 28 that constitutes an electric power steering device 22 relative to a housing 30.

[0105] The electric power steering device 22 of this example is configured as a rack-assist electric power steering device. However, a self-aligning ball bearing according to one aspect of the present disclosure can also be applied to a bearing that supports, in a housing, the pinion shaft of a rack-and-pinion steering gear unit that constitutes a column-assist electric power steering device or a pinion-assist electric power steering device.

[0106] In the following description, the terms "front-rear direction," "up-down direction," and "left-right direction" refer to the front-rear direction, up-down direction, and left-right direction of the vehicle incorporating the electric power steering device 22 when the vehicle is placed on a horizontal surface.

[0107] The electric power steering device 22 of this example includes a steering wheel 23, a steering shaft 24, a steering column 25, universal joints 26a and 26b, an intermediate shaft 27, a steering gear unit 28, and an assist mechanism 29.

[0108] The steering wheel 23 is fixedly supported at the rear end of a steering shaft 24. The steering shaft 24 is rotatably supported inside a steering column 25 that is supported on the vehicle body. The front end of the steering shaft 24 is connected to a first pinion shaft 31 of a steering gear unit 28 via a rear universal joint 26a, an intermediate shaft 27, and a front universal joint 26b so as to be able to transmit torque.

[0109] The steering gear unit 28 includes a housing 30, a first pinion shaft 31, a rack shaft 32, and a first pressing mechanism 33. The steering gear unit 28 converts the rotational movement of the steering wheel 23 into linear movement in the axial direction of the rack shaft 32.

[0110] The housing 30 is fixed to the vehicle body using fastening members such as bolts and studs, and is made by die-casting a light alloy such as an aluminum alloy. The housing 30 includes a rack housing 34, a first pinion housing 35, a sensor housing 36, a first pressing mechanism housing 37, a second pinion housing (not shown), and a second pressing mechanism housing (not shown).

[0111] The rack housing 34 has a generally cylindrical shape that extends in the left-right direction. The rack housing 34 is open at both axial ends. The axial middle portion of the rack shaft 32 is housed inside the rack housing 34. The rack housing 34 is disposed generally horizontally.

[0112] The first pinion accommodating portion 35 has a generally cylindrical shape that extends in the vertical direction. The tip half of the first pinion shaft 31 is rotatably disposed inside the first pinion accommodating portion 35. In this example, the first pinion accommodating portion 35 is disposed in front of the rack accommodating portion 34 (the near side in FIG. 5, the left side in FIG. 6) and on one axial side of the rack accommodating portion 34 (the right side in FIG. 5).

[0113] Furthermore, the first pinion accommodating portion 35 is disposed in a skewed positional relationship with respect to the rack accommodating portion 34. In other words, the central axis of the first pinion accommodating portion 35 and the central axis of the rack accommodating portion 34 are in a skewed positional relationship. The internal space of the first pinion accommodating portion 35 communicates with the internal space of the rack accommodating portion 34. The opening on the lower side of the first pinion accommodating portion 35 is closed by a lower lid 38.

[0114] The sensor accommodating portion 36 has a generally stepped cylindrical shape and is provided above the first pinion accommodating portion 35. The inside of the sensor accommodating portion 36 accommodates an intermediate portion of the first pinion shaft 31 and a torque sensor that constitutes the assist mechanism 29. In this example, the sensor accommodating portion 36 is provided in an upper cover 39 that is attached to an opening on the upper side of the first pinion accommodating portion 35.

[0115] The first pressing mechanism housing 37 has a generally cylindrical shape that extends in the front-to-rear direction. The first pressing mechanism 33 is housed inside the first pressing mechanism housing 37. The first pressing mechanism housing 37 is disposed on the rear side of the rack housing 34 (the back side in FIG. 5, the right side in FIG. 6) and on one axial side of the rack housing 34. Specifically, the first pressing mechanism housing 37 is disposed at the same position as the first pinion housing 35 in the axial direction of the rack housing 34. The internal space of the first pressing mechanism housing 37 also communicates with the internal space of the rack housing 34.

[0116] The second pinion housing has a generally cylindrical shape that extends vertically. The tip half of the second pinion shaft that constitutes assist mechanism 29 is rotatably disposed inside the second pinion housing. The second pinion housing is disposed on the other axial side (the left side in FIG. 5) of rack housing 34.

[0117] Furthermore, the second pinion accommodating portion is disposed in a skewed positional relationship with respect to the rack accommodating portion 34. In other words, the central axis of the second pinion accommodating portion and the central axis of the rack accommodating portion 34 are in a skewed positional relationship. For example, the central axis of the second pinion accommodating portion and the central axis of the rack accommodating portion 34 can be disposed so as to be perpendicular to each other when viewed from a direction perpendicular to these central axes. The internal space of the second pinion accommodating portion is in communication with the internal space of the rack accommodating portion 34.

[0118] The second pressing mechanism housing has a generally cylindrical shape that extends in the front-to-rear direction. A second pressing mechanism that presses the second pinion shaft toward the rack shaft 32 is housed inside the second pressing mechanism housing. The second pressing mechanism housing is disposed on the other axial side of the rack housing 34. Specifically, the second pressing mechanism housing is disposed at the same position as the second pinion housing in the axial direction of the rack housing 34. The internal space of the second pressing mechanism housing is also in communication with the internal space of the rack housing 34.

[0119] The first pinion shaft 31 is configured by connecting a pinion body 41 having first pinion teeth 40 on the tip half of its outer circumferential surface to a hollow shaft 42 via a torsion bar 43. Specifically, the first pinion shaft 31 is configured by arranging the torsion bar 43 inside the hollow shaft 42, connecting the upper end of the torsion bar 43 to the upper end of the hollow shaft 42, and connecting the lower end of the torsion bar 43 to the upper end of the pinion body 41.

[0120] Pinion body 41 forms the front half (lower half) of first pinion shaft 31 and is rotatably supported by two rolling bearings 62a, 62b inside first pinion accommodating portion 35. In the illustrated example, rolling bearings 62a, 62b are each formed by a single-row deep groove ball bearing. However, two rolling bearings 62a, 62b may also be formed by other rolling bearings such as angular contact ball bearings, tapered roller bearings, roller bearings, etc.

[0121] The hollow shaft 42 constitutes the base half (upper half) of the first pinion shaft 31, and is rotatably supported inside the sensor accommodating portion 36 by a self-aligning ball bearing 1a according to one aspect of the present disclosure. Therefore, even if the central axis of the hollow shaft 42 is inclined with respect to the central axis of the sensor accommodating portion 36, the hollow shaft 42 can rotate smoothly.

[0122] The rack shaft 32 is a rod-shaped member made of a metal such as carbon steel or stainless steel, and is disposed with its axial direction (longitudinal direction) facing the left-right direction. The rack shaft 32 has, on a portion of its outer circumferential surface on one axial side, first rack teeth 44 that mesh with first pinion teeth 40 provided on the outer circumferential surface of the first pinion shaft 31, and has, on a portion of its outer circumferential surface on the other axial side, second rack teeth 45 that mesh with second pinion teeth 57 provided on the outer circumferential surface of the second pinion shaft 53.

[0123] The rack shaft 32 is disposed inside the rack housing 34 so as to be able to move back and forth in its axial direction. Both axial ends of the rack shaft 32 protrude from openings on both axial sides of the rack housing 34 and are connected to tie rods 47 via spherical joints 46.

[0124] In the electric power steering device 22, the rotation of the first pinion shaft 31 caused by the driver's operation of the steering wheel 23 is converted into linear motion of the rack shaft 32. The linear motion of the rack shaft 32 pushes and pulls the tie rod 47, thereby applying a steering angle to the steered wheels 48.

[0125] The first pressing mechanism 33 elastically presses the rack shaft 32 toward the first pinion shaft 31. Specifically, the first pressing mechanism 33 includes a rack guide 49 disposed inside the first pressing mechanism housing portion 37 so as to be movable toward and away from the rack shaft 32, a cap 50 threadedly attached to the opening of the first pressing mechanism housing portion 37, and an elastic member 51 disposed between the rack guide 49 and the cap 50 in an elastically compressed state. The first pressing mechanism 33 elastically presses the rack shaft 32 toward the first pinion shaft 31 using the rack guide 49 based on the elastic restoring force of the elastic member 51, thereby eliminating backlash at the meshing portion between the first pinion teeth 40 and the first rack teeth 44.

[0126] The assist mechanism 29 applies a steering assist force to the rack shaft 32, thereby reducing the steering force required for the driver to operate the steering wheel 23. In this example, the assist mechanism 29 includes an electric motor 52 as an auxiliary power source, a second pinion shaft 53, a second pressing mechanism (not shown), a worm reducer 54, an electronic control unit 55, and a torque sensor 56.

[0127] The second pinion shaft 53 has second pinion teeth 57 on the front half of its outer circumferential surface that mesh with the second rack teeth 45. The second pinion shaft 53 is rotatably supported inside the second pinion accommodating portion of the housing 30. The second pinion shaft 53 is rotationally driven by the electric motor 52 via the worm reducer 54.

[0128] The second pressing mechanism elastically presses the rack shaft 32 toward the second pinion shaft 53. Specifically, the second pressing mechanism includes a rack guide disposed inside the second pressing mechanism housing so as to be movable toward and away from the rack shaft 32, a cap threadedly attached to an opening of the second pressing mechanism housing, and an elastic member disposed in an elastically compressed state between the rack guide and the cap. The second pressing mechanism elastically presses the rack shaft 32 toward the second pinion shaft 53 using the rack guide based on the elastic restoring force of the elastic member, thereby eliminating backlash at the meshing portion between the second pinion teeth 57 and the second rack teeth 45.

[0129] The worm reducer 54 includes a worm 58 and a worm wheel 59, and reduces the speed of rotation of the electric motor 52 (increases the torque) and transmits the reduced speed to the second pinion shaft 53. The worm 58 has worm teeth on its outer circumferential surface, and is connected to the output shaft of the electric motor 52 via a joint (not shown) or the like to enable the transmission of torque. The worm wheel 59 has wheel teeth on its outer circumferential surface that mesh with the worm teeth, and is fixed to the base end of the second pinion shaft 53 so as not to rotate relative to it.

[0130] The electronic control unit 55 controls the driving of the electric motor 52 .

[0131] The torque sensor 56 is disposed inside the sensor housing portion 36. The torque sensor 56 is disposed around the first pinion shaft 31, detects the rotation direction and torque of the first pinion shaft 31, and outputs a signal corresponding to the detected rotation direction and torque to the electronic control unit 55.

[0132] An electronic control unit 55 electrically connected to the torque sensor 56 controls the driving of the electric motor 52 based on the output signal of the torque sensor 56. As a result, the driving torque generated by the electric motor 52 is transmitted as a steering assist force to the rack shaft 32 via the worm reduction gear 54 and the second pinion shaft 53. As a result, the steering force required for the driver to operate the steering wheel 23 can be reduced. [Explanation of symbols]

[0133] 1, 1a Self-aligning ball bearing 2 outer ring 3, 3a Inner circle 4a First ball 4b Second ball 5 Outer raceway 6, 6a Inner raceway 7a, 7b Concave curved part 8, 8a Connection surface 9 Cage 10a First pocket 10b Second pocket 11a first retainer element 11b second retainer element 12a 1st board part 12b Second board section 13a First large curved plate section 13b Second large curved plate section 14a First small curved plate section 14b 2nd small curved plate part 15a 1st board piece 15b 2nd board piece 16 Rivets 17a 1st through hole 17b 2nd hole 18 Rod 19 Crimping part 20 heads 21a, 21b Connecting concave curved surface portion 22 Electric power steering device 23 Steering wheel 24 Steering shaft 25 Steering column 26a, 26b Universal joint 27 Intermediate shaft 28 Steering gear unit 29 Assist mechanism 30 Housing 31 First pinion shaft 32 Rack shaft 33 First pressing mechanism 34 Rack storage area 35 First pinion housing 36 Sensor housing 37 First pressing mechanism housing 38 Lower lid 39 Top lid 40 1st pinion teeth 41 Pinion body 42 Hollow shaft 43 Torsion bar 44 First rack tooth 45 Second rack tooth 46 Spherical joint 47 tie rod 48 Steering Wheel 49 Rack guide 50 caps 51 Elastic member 52 Electric motor 53 Second pinion shaft 54 Worm reducer 55 Electronic Control Unit 56 Torque sensor 57 Second pinion tooth 58 Warm 59 Worm Wheel 60a, 60b groove shoulder 61 Center groove shoulder 62a, 62b Rolling bearings 100 Self-aligning ball bearing 101 outer ring 102 Inner circle 103a, 103b ball 104 Outer raceway 105a, 105b inner raceway 106 Cage 107 Rim 108a, 108b Column section 109a, 109b pockets

Claims

1. an outer ring having an outer ring raceway formed on its inner circumferential surface by a partial spherical concave surface centered on the bearing center; an inner ring having an inner ring raceway on an outer peripheral surface thereof, the inner ring raceway facing the outer ring raceway; a plurality of balls disposed between the outer ring raceway and the inner ring raceway; Equipped with the plurality of balls include a plurality of first balls whose centers are located at a first axial position and a plurality of second balls whose centers are located at a second axial position different from the first axial position, an axial distance between the first axial position and the second axial position is equal to or less than a ball diameter of the plurality of balls; Self-aligning ball bearing.

2. the plurality of first balls and the plurality of second balls are arranged alternately one by one in the circumferential direction; 2. The self-aligning ball bearing according to claim 1.

3. the bearing further includes a cage having a plurality of first pockets for rollingly holding the plurality of first balls and a plurality of second pockets for rollingly holding the plurality of second balls, the cage includes a first cage element and a second cage element, each of which is an annular pressed product; the first cage element has a flat first base plate portion, first large curved plate portions each having a partial spherical shell shape and arranged at a plurality of positions in the circumferential direction, and first small curved plate portions each having a partial spherical shell shape and each having a smaller protrusion amount from the first base plate portion than the first large curved plate portions, the second cage element has a flat second base plate portion, second large curved plate portions each having a partial spherical shell shape and arranged at a plurality of positions in the circumferential direction, and second small curved plate portions each having a partial spherical shell shape and each having a smaller protrusion amount from the second base plate portion than the second large curved plate portions, the retainer is configured by coupling and fixing the first retainer element and the second retainer element in a state in which the first substrate portion and the second substrate portion are overlapped, Each of the plurality of first pockets is formed by a portion surrounded by the first large curved plate portion and the second small curved plate portion, and each of the plurality of second pockets is formed by a portion surrounded by the second large curved plate portion and the first small curved plate portion.

2. The self-aligning ball bearing according to claim 1.

4. a resilient force is applied to the plurality of first balls and the plurality of second balls in a direction away from each other in the axial direction based on the resilience of the cage; 4. The self-aligning ball bearing according to claim 3.

5. the inner ring raceway includes two concavely curved surface portions disposed on both sides in the axial direction and having a generatrix shape of an arc, and a connecting surface portion disposed in an intermediate portion in the axial direction and connecting the two concavely curved surface portions to each other.

2. The self-aligning ball bearing according to claim 1.

6. The connection surface portion is configured by a cylindrical surface whose outer diameter does not change in the axial direction.

6. The self-aligning ball bearing according to claim 5.

7. The connecting surface portion has two connecting concave curved surface portions each curved in a direction in which the outer diameter becomes smaller from the axial center portion toward the axial outside.

6. The self-aligning ball bearing according to claim 5.

Images