Spherical roller bearing

Abstract

In the present invention, a plurality of column portions on one side of an annular body in the axial direction and a plurality of column portions on the other side of the annular body in the axial direction are arranged so as to have the same phase in the circumferential direction. The annular body has: an outer protruding section that protrudes further outward than the column portions in the radial direction and is guided into the inner circumferential surface of the outer ring; and a small distance portion that has a radial-direction distance that is smaller than the outer diameter of the outer protruding section in order to enable the cage to be inserted into the outer ring in the axial direction in a state in which the axes of the outer ring and the cage are orthogonal to each other.

Description

Self-aligning roller bearing

[0001] The present invention relates to a self-aligning roller bearing.

[0002] As a self-aligning roller bearing, for example, the one described in Patent Document 1 is known. The self-aligning roller bearing of Patent Document 1 includes an outer ring having a raceway surface formed by a part of a spherical surface on its inner circumference, and on its outer circumference, there are two symmetrically arranged on the left and right with respect to a cross-section passing through the axial center and perpendicular to the axis, and having the same radius as a part of the spherical surface in a cross-section including the axis. An inner ring having a cylindrical surface formed between the two raceway surfaces, a plurality of convex rollers respectively arranged between the raceway surface of the outer ring and the two raceway surfaces of the inner ring, and having an outer peripheral surface that coincides with the raceway surface of the inner and outer rings, and a metal cage provided with pockets for arranging the convex rollers at predetermined intervals in the circumferential direction. And the maximum diameter of the cage is larger than the inner diameter of the end face of the outer ring, and the cage is divided at two locations in the circumferential direction.

[0003] According to the self-aligning roller bearing of Patent Document 1, by dividing the cage into two parts in the circumferential direction, it becomes possible to assemble even if the maximum outer diameter of the cage is larger than the inner diameter (minimum inner diameter) of the end face of the outer ring. Thereby, the width of the outer ring is widened more than before, the raceway surface of the inner ring is made larger, and the allowable alignment angle of the self-aligning roller bearing is made larger.

[0004] Japanese Patent Application Laid-Open No. 2009-180307

[0005] However, in the self-aligning roller bearing of Patent Document 1, since the cage is divided into two parts in the circumferential direction for incorporation into the outer ring, the number of parts and the working processes increase, resulting in a decrease in productivity.

[0006] Therefore, an object of the present invention is to provide a self-aligning roller bearing that can be incorporated into the outer ring without dividing the cage.

[0007] To solve the above problems, the present invention may adopt the following configuration: (1) A self-aligning roller bearing comprising: an inner ring having two rows of inner ring raceway surfaces on its outer circumference; an outer ring having a spherical concave outer ring raceway surface on its inner circumference; a plurality of rollers provided in two rows so as to be able to roll between the two rows of inner ring raceway surfaces and the outer ring raceway surface; and a cage that holds the two rows of the plurality of rollers, wherein the cage comprises: an annular body in the shape of a ring extending along the circumferential direction; a plurality of columnar portions provided so as to project outward in the axial direction at regular intervals in the circumferential direction from both axial sides of the annular body; a plurality of pockets formed by both axial sides of the annular body and adjacent columnar portions in the circumferential direction, each holding the rollers, wherein the plurality of columnar portions on one axial side of the annular body and the plurality of columnar portions on the other axial side of the annular body are arranged so as to have the same phase with respect to the circumferential direction; and the annular body has an outer convex portion that projects radially outward from the columnar portions and is guided to the inner circumferential surface of the outer ring, A self-aligning roller bearing characterized by having a small spacing portion having a radial spacing smaller than the outer diameter of the outer protrusion, such that the cage can be inserted axially into the outer ring when the axes of the outer ring and the cage are perpendicular to each other.

[0008] According to the present invention, it is possible to provide a self-aligning roller bearing that can be incorporated into the outer ring without dividing the cage.

[0009] Figure 1 is a cross-sectional view of a self-aligning roller bearing according to the first embodiment of the present invention. Figure 2 is a cage according to the first embodiment. Figure 3 is a diagram showing how a cage according to a comparative example is assembled onto the outer ring. Figure 4 is a cross-sectional view of the cage of a self-aligning roller bearing in the portion where a notch is provided in the cage. Figure 5 is a diagram showing the area around the notch of the cage as viewed from the radial direction, and corresponds to the lower part of Figure 7. Figure 6 is a diagram showing the area around the notch of the cage as viewed from the radial direction, and corresponds to the upper part of Figure 7. Figure 7 is a diagram showing how the cage according to this embodiment is assembled onto the outer ring. Figure 8 is a cross-sectional view of a cage of a self-aligning roller bearing according to a modified example. Figure 9 is a cross-sectional view showing a combination bearing. Figure 10 is a cross-sectional view showing a combination bearing with spacers. Figure 11 is a perspective view of a cage according to the second embodiment of the present invention. Figure 12 is a view of the area around the notch of the cage of Figure 11 as viewed from the radial direction. Figure 13 is a view of the area around the notch of the cage according to a modified example as viewed from the radial direction.

[0010] Figure 1 is a cross-sectional view of a self-aligning roller bearing according to the first embodiment of the present invention. Figure 2 is a cage according to the first embodiment.

[0011] As shown in Figures 1 and 2, the self-aligning roller bearing 1 comprises an inner ring 10 having two rows of inner ring raceway surfaces 11, 11 on its outer circumference, an outer ring 20 having an outer ring raceway surface 21 which is a spherical concave surface on its inner circumference, a plurality of rollers 3, 3 arranged in two rows so as to be able to roll between the two rows of inner ring raceway surfaces 11, 11 and the outer ring raceway surface 21, and a cage 30 that holds the plurality of rollers 3, 3 in the two rows.

[0012] The outer ring 20 has a spherical concave raceway surface 21 on its inner circumferential surface, and the center of curvature of this raceway surface 21 coincides with the center of the self-aligning roller bearing 1, thereby ensuring the self-aligning capability of the self-aligning roller bearing 1. At the axial center of the outer ring 20, a lubricant injection hole 23 is formed so as to penetrate the outer ring 20 radially, at least one such hole in the circumferential direction for injecting lubricant. Note that, as will be described later with reference to Figure 7, the lubricant injection hole 23 does not necessarily have to be provided.

[0013] Each roller 3, positioned in each row, has a barrel-shaped rolling surface and rolls between the inner ring raceway surface 11 and the outer ring raceway surface 21.

[0014] The retainer 30 is a metal, machined retainer, and is used as an outer ring guide. The retainer 30 comprises an annular body 31 extending along the circumferential direction, a plurality of columnar portions 33, 33 provided so as to protrude axially outward at regular intervals in the circumferential direction from both axial sides 31a, 31a of the annular body 31, and a plurality of pockets 34, 34 formed by both axial sides 31a, 31a of the annular body 31 and adjacent columnar portions 33, 33 in the circumferential direction, each holding a roller 3.

[0015] As shown in Figure 1, the annular body 31 is an annular shape that extends along the circumferential direction in the axial center of the self-aligning roller bearing 1, between the two rows of inner ring raceway surfaces 11, 11. Two rows of columnar portions 33, 33 are provided on both sides of the annular body 31 in the axial direction. The columnar portions 33, 33 on one side of the annular body 31 in the axial direction and the columnar portions 33, 33 on the other side of the annular body 31 in the axial direction are arranged so that their phase in the circumferential direction is the same. Therefore, when the cage 30 is viewed from the axial direction, the columnar portions 33, 33 on one side of the annular body 31 in the axial direction and the columnar portions 33, 33 on the other side of the annular body 31 in the axial direction are in overlapping positions.

[0016] The retainer 30 configured in this way independently houses the rollers 3, 3 of each row in each pocket 34, thereby forming each row of rollers on both sides of the annular body 31 in the axial direction, and holds each roller 3, 3 of each row so that it can roll freely at a constant interval along its circumferential direction. Furthermore, since the multiple columnar portions 33, 33 on one side in the axial direction and the multiple columnar portions 33, 33 on the other side in the axial direction are arranged so that their phases in the circumferential direction are the same, the multiple pockets 34, 34 and multiple rollers 3, 3 on one side in the axial direction and the multiple pockets 34, 34 and multiple rollers 3, 3 on the other side in the axial direction are also arranged so that their phases in the circumferential direction are the same.

[0017] In planetary gears for slewing speed reducers, the self-aligning roller bearing 1 revolves around the sun gear, and the gear itself also rotates at high speed. In such operating environments, the cage 30 swings around considerably, so it is preferable to adopt a specification that guides the cage 30 to the outer ring in order to suppress the swinging motion. Therefore, the annular body 31 of this embodiment has an outer projection 35 that protrudes radially outward from the column portion 33 and is guided to the inner circumferential surface of the outer ring 20. The outer projection 35 is substantially annular in shape overall. The outer circumferential surface of the outer projection 35 is a guide surface 35a that is guided to the inner circumferential surface of the outer ring 20.

[0018] Figure 3 shows how the retainer according to the comparative example is assembled onto the outer ring. The retainer 30 of the comparative example shown in Figure 3 does not have the pair of notches 37, 37 which will be described later. As shown in Figures 1 and 3, the maximum diameter of the retainer 30, that is, the outer diameter of the outer projection 35 of the retainer 30, is larger than the inner diameters of the axial sides 25, 25 of the outer ring 20. Therefore, when attempting to insert the retainer 30 onto the outer ring 20, the outer projection 35 catches on the axial sides 25 of the outer ring 20, making it impossible to assemble.

[0019] Figure 4 is a cross-sectional view of the cage of a self-aligning roller bearing in the portion where a notch is provided in the cage. To resolve the assembly problems described above, as shown in Figures 2 and 4, notches 37, 37 are provided in two locations on the outer protrusion 35 that are radially opposite to each other. That is, the pair of notches 37, 37 are formed in two locations on the outer protrusion 35 that are offset by 180° in the circumferential direction. As shown in Figures 2 and 4, the pair of notches 37, 37 have parallel planar shapes, and these planar shapes are substantially perpendicular to the radial direction of the cage 30.

[0020] Figure 5 shows the area around the notch of the retainer as viewed from the radial direction, and corresponds to the lower part of Figure 7. Figure 6 shows the area around the notch of the retainer as viewed from the radial direction, and corresponds to the upper part of Figure 7.

[0021] As shown in Figure 5, the circumferential center portion 37M of the notch 37 in the lower part of Figure 7 is approximately at the same circumferential position as the circumferential center portions 33Ma of the column portions 33 on both sides in the axial direction.

[0022] As shown in Figure 6, the circumferential center portion 37M of the notch 37 in the upper part of Figure 7 substantially coincides with the circumferential center portion 33Mb between a pair of adjacent column portions 33, 33 in the circumferential direction.

[0023] As shown in Figures 5 and 6, the circumferential position of the circumferential center portion 37M of the notch 37 is approximately the same as the circumferential center portion 33Ma of the column portion 33, or the circumferential center portion 33Mb between a pair of adjacent column portions 33, 33 in the circumferential direction, thereby improving the weight balance of the retainer 30.

[0024] In Figures 5 to 7, multiple columnar sections 33, 33 located in positions that overlap with the notch 37 in the circumferential direction are indicated by reference numeral 33A as first columnar sections. That is, the first columnar section 33A is a columnar section 33 located in the circumferential region S between the circumferential ends 37a, 37b of the notch 37. Note that if it overlaps with the circumferential region S even partially, it is considered a first columnar section 33A. In addition, multiple columnar sections 33, 33 located in positions that do not overlap with the notch 37 in the circumferential direction are indicated by reference numeral 33B as second columnar sections in Figure 7.

[0025] Figure 7 shows how the retainer according to this embodiment is assembled onto the outer ring. As shown in Figure 7, the portion of the outer protrusion 35 in which the pair of notches 37, 37 are formed has a thinner radial wall thickness. That is, the portion in which the pair of notches 37, 37 are formed can be said to be a small-interval portion 38 having a radial spacing A smaller than the outer diameter of the outer protrusion 35. Thus, the annular body 31 has an outer protrusion 35 and a small-interval portion 38. As a result, the radial spacing A of the small-interval portion 38 between the pair of notches 37, 37 is smaller than the inner diameter B of the axial sides 25, 25 of the outer ring 20. This makes it possible to assemble the retainer 30 onto the outer ring 20 by inserting the retainer 30 axially into the outer ring 20 from the pair of notches 37, 37.

[0026] The assembly of the self-aligning roller bearing 1 involves first assembling the rollers 3 (not shown in Figure 7) and the cage 30 onto the inner ring raceway surface 11 of the inner ring 10 (not shown in Figure 7). With the axes of the outer ring 20 and the cage 30 perpendicular to each other, the cage 30, which integrates the inner ring 10 and the rollers 3, is inserted axially into the outer ring 20. Then, the cage 30, which has been inserted axially, is rotated 90° so that its axis is parallel to the outer ring 20, and the cage 30, which integrates the inner ring 10 and the rollers 3, is assembled into the outer ring 20. Note that when inserting the cage 30 into the outer ring 20 axially, the rollers 3 that are incorporated in the area overlapping the pair of notches 37, 37 in the circumferential direction interfere with the axial sides 25 of the outer ring 20, so they are removed. After the cage 30 is assembled into the outer ring 20, the cage 30 is tilted to align itself and assembled.

[0027] Figure 8 is a cross-sectional view of the cage of a modified self-aligning roller bearing. As shown in Figure 8, the outer ring raceway surface 21 does not necessarily need to have a lubricant injection hole 23. However, as shown in Figure 4, it is preferable to have a lubricant injection hole 23 on the outer ring raceway surface 21 because a space between the lubricant injection hole 23 and the notch 37 is expected to improve lubrication.

[0028] As described above, according to the self-aligning roller bearing 1 of this embodiment, the annular body 31 has an outer projection 35 that protrudes radially outward from the column portion 33 and is guided by the inner circumferential surface of the outer ring 20, and a small-gap portion 38 having a radial gap A smaller than the outer diameter of the outer projection 35, so that the cage 30 can be inserted axially into the outer ring 20 when the axes of the outer ring 20 and the cage 30 are perpendicular to each other. Therefore, the cage 30, which has an outer projection 35 and is guided by the outer ring, can be assembled into the outer ring 20 in its original state without being divided as in the conventional Patent Document 1. Therefore, the number of required parts is reduced and the man-hours required when assembling the cage are also reduced, leading to improved productivity.

[0029] Furthermore, the small interval section 38 is formed by providing notches 37, 37 at two radially opposite locations on the outer protrusion 35, and the circumferential center 37M of the notch 37 substantially coincides with the circumferential center 33Ma of the column section 33, or the circumferential center 33Mb between a pair of circumferentially adjacent column sections 33, 33. The circumferential positions substantially coincide. By providing the notch 37 at such positions, the weight balance of the retainer 30 is improved.

[0030] Figure 9 is a cross-sectional view showing a combination bearing. Figure 10 is a cross-sectional view showing a combination bearing with a spacer. As shown in Figures 9 and 10, a combination bearing may be applied by combining multiple self-aligning roller bearings 1 according to the above embodiment. The combination bearing 100 shown in Figure 9 is an example in which a pair of the above-described self-aligning roller bearings 1 are arranged adjacent to each other in the axial direction. The combination bearing 100 shown in Figure 10 is an example in which a pair of the above-described self-aligning roller bearings 1 are arranged adjacent to each other in the axial direction with a spacer 40 in between. The spacer 40 may also be provided with a lubricant injection hole that penetrates the spacer 40 radially.

[0031] Figure 11 is a perspective view of a retainer according to a second embodiment of the present invention. Figure 12 is a view of the area around the notch of the retainer in Figure 11, viewed from the radial direction. As shown in Figure 12, in this embodiment, the circumferential central portion 37M of the notch 37 substantially coincides with the circumferential central portion 33Ma of the column portions 33 on both axial sides.

[0032] Furthermore, the multiple column portions 33 include a plurality of first column portions 33A, 33A provided at positions that overlap with the notch 37 in the circumferential direction (within the circumferential region S described above), and a plurality of second column portions 33B, 33B (see Figure 11) provided at positions that do not overlap with the notch 37 in the circumferential direction.

[0033] In the examples shown in Figures 11 and 12, the outer diameters of the two central column sections 33C, 33C, which are located closest to the circumferential center among the multiple first column sections 33A, 33A, are smaller than the outer diameters of the multiple second column sections 33B, 33B. In other words, in this modified example, all of the multiple first column sections 33A, 33A except for the central column section 33C have the same shape as the multiple second column sections 33B, 33B, but the central column section 33C has a different shape from the other column sections 33.

[0034] In the central column section 33C, the radial outer surface is cut out to form a notched surface 39, and its outer diameter is smaller compared to the radial outer surfaces of the other column sections 33. This makes the outer diameter of the central column section 33C, which is most likely to catch on the outer ring 20 when inserting the retainer 30 into the outer ring 20, smaller.

[0035] In the examples shown in Figures 11 and 12, of the multiple first column portions 33A, 33A, only the central column portion 33C, which is located closest to the circumferential center, is set to have a smaller outer diameter than the second column portion 33B. However, the other first column portions 33A may also be set to have a smaller outer diameter than the second column portion 33B by providing notched surfaces 39. In this case, when inserting the retainer 30 into the outer ring 20, it is possible to more reliably prevent the multiple first column portions 33A, 33A from getting caught on the outer ring 20. Furthermore, since the multiple column portions 33, 33 on one axial side of the annular body 31 and the multiple column portions 33, 33 on the other axial side of the annular body 31 are arranged so that their phase in the circumferential direction is the same, the number of column portions 33 that require notched surfaces 39 can be reduced, improving productivity during processing.

[0036] Figure 13 is a view of the area around the notch of the modified retainer, as seen from the radial direction. As shown in Figure 13, in this modified example, the circumferential central portion 37M of the notch 37 is approximately aligned with the circumferential central portion 33Mb between a pair of adjacent column portions 33, 33 in the circumferential direction.

[0037] In the example shown in Figure 13, the outer diameters of the four central column sections 33C, 33C, which are located closest to the circumferential center among the multiple first column sections 33A, 33A, are smaller than the outer diameters of the multiple second column sections 33B, 33B. In the central column section 33C, the radial outer surface is notched, forming a notched surface 39, and its outer diameter is smaller compared to the radial outer surface of the other column sections 33. This ensures that the outer diameter of the central column section 33C, which is most likely to catch on the outer ring 20 when inserting the retainer 30 into the outer ring 20, is set to be smaller.

[0038] The present invention is not limited to the embodiments described above. It is also intended and within the scope of protection to be provided for the combination of each configuration of the embodiments, as well as for modifications and applications by those skilled in the art based on the description in the specification and well-known art.

[0039] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

[0040] This application is based on a Japanese patent application (Patent Application No. 2024-174985) filed on October 4, 2024, the contents of which are incorporated herein by reference.

[0041] 1 Self-aligning roller bearing 3 Rollers 10 Inner ring 11 Inner ring raceway surface 20 Outer ring 21 Outer ring raceway surface 23 Lubricant injection hole 25 Axial side surface 30 Cage 31 Annular body 31a Axial side surface 33 Column 33A First column 33B Second column 33C Central column 34 Pocket 35 Outer protrusion 35a Guide surface 37 Notch 37a, 37b Circumferential end 38 Small spacing 39 Notched surface 40 Spacer 100 Combination bearing

Claims

1. A self-aligning roller bearing comprising: an inner ring having two rows of inner ring raceway surfaces on its outer circumference; an outer ring having a spherical concave outer ring raceway surface on its inner circumference; a plurality of rollers arranged in two rows so as to be able to roll between the two rows of inner ring raceway surfaces and the outer ring raceway surface; and a cage that holds the two rows of the plurality of rollers, wherein the cage comprises: an annular body in the shape of a ring extending along the circumferential direction; a plurality of columnar portions provided so as to project outward in the axial direction at regular intervals from both axial sides of the annular body in the circumferential direction; a plurality of pockets formed by both axial sides of the annular body and adjacent columnar portions in the circumferential direction, each holding the rollers, wherein the plurality of columnar portions on one axial side of the annular body and the plurality of columnar portions on the other axial side of the annular body are arranged so as to have the same phase with respect to the circumferential direction; and the annular body has an outer convex portion that projects radially outward from the columnar portions and is guided to the inner circumferential surface of the outer ring. A self-aligning roller bearing characterized by having a small spacing portion having a radial spacing smaller than the outer diameter of the outer protrusion, such that the cage can be inserted axially into the outer ring when the axes of the outer ring and the cage are perpendicular to each other.

2. The small interval portion is formed by providing notches in two radially opposite locations on the outer protrusion, and the circumferential center portion of the notch substantially coincides with the circumferential center portion of the column portion, or the circumferential center portion between a pair of circumferentially adjacent column portions, the self-aligning roller bearing according to claim 1.

3. The self-aligning roller bearing according to claim 2, wherein the plurality of column portions include a plurality of first column portions provided at positions overlapping with the notch in the circumferential direction, and a plurality of second column portions provided at positions not overlapping with the notch in the circumferential direction, wherein at least the outer diameter of the central column portion located closest to the circumferential center of the plurality of first column portions is smaller than the outer diameter of the plurality of second column portions.

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