Motion guide device

Abstract

The present invention is a motion guide device (1) provided with an inner ring (10), an outer ring (20), a plurality of rolling bodies (30), and retainers (40, 50). The retainers (40, 50) have a plurality of partition walls (41, 51) and a pair of bands (42, 43, 52, 53). The retainers (40, 50) include a radial retainer (40) that holds a plurality of first rolling bodies (31) among the plurality of rolling bodies (30), and an axial retainer (50) that holds a plurality of second rolling bodies (32) among the plurality of rolling bodies (30). The pair of bands (52, 53) of the axial retainer (50) are disposed on both sides in the radial direction of the plurality of partition walls (51), and the dimension of one band (53) in the radial direction is smaller than the dimension of the other band (52) in the radial direction.

Description

Movement guide device

[0001] This application claims priority to Japanese Patent Application No. 2024-048206, filed on March 25, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 below discloses a compound roller type slewing bearing that can bear both thrust loads and radial loads. In this compound roller type slewing bearing, cylindrical rollers for bearing thrust loads and cylindrical rollers for bearing radial loads are arranged between an inner ring and an outer ring and are each held by a cage (see FIG. 3).

[0003] Japanese Patent Publication No. 8-105438

[0004] In the motion guide device described above, a retainer (cage) is used to prevent contact between the rolling elements (cylindrical rollers) and to control the orientation of the rolling elements. The retainer is curved in the circumferential direction along the orbit of the rolling elements. Therefore, for molding purposes, the pair of bands of the radial retainer are arranged alternately in the radial direction. However, there is a possibility that the band arranged on the axial retainer side of the radial retainer may interfere with the axial retainer.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to avoid interference between a radial retainer and an axial retainer.

[0006] In order to solve the above problems, a first aspect of the present invention is a motion guide device comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a retainer that holds the plurality of rolling elements, wherein the retainer has a plurality of partition walls arranged between the plurality of rolling elements and a pair of bands that connect the plurality of partition walls circumferentially, and the retainer comprises a radial retainer that holds a plurality of first rolling elements that receive radial loads among the plurality of rolling elements, and an axial retainer that holds a plurality of second rolling elements that receive axial loads, wherein the pair of bands of the axial retainer are arranged on both radial sides of the plurality of partition walls of the axial retainer, and the radial dimension of one of the pair of bands of the axial retainer that is arranged on the radial retainer side is smaller than the radial dimension of the other band that is arranged on the opposite side of the radial retainer.

[0007] A second aspect of the present invention is the motion guide device of the first aspect, wherein the cross-sectional area of ​​the one band is substantially equal to the cross-sectional area of ​​the other band.

[0008] A third aspect of the present invention is the motion guide device according to the first or second aspect, wherein at least one of the plurality of partition walls of the axial retainer has a plurality of protrusions on an end surface in the axial direction.

[0009] A fourth aspect of the present invention is a motion guide device of the first or second aspect, wherein the pair of bands of the radial retainer are arranged on both axial sides of the multiple partition walls of the radial retainer and are arranged offset in the radial direction.

[0010] According to the present invention, interference between the radial retainer and the axial retainer can be avoided.

[0011] FIG. 1 is a perspective view of a motion guide device according to one embodiment. FIG. 2 is an exploded perspective view of a motion guide device according to one embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of a motion guide device according to one embodiment. FIG. 4 is a plan view of an axial retainer according to one embodiment. FIG. 5 is a cross-sectional view taken along line VV shown in FIG. 4. FIG. 6 is a cross-sectional view taken along line VII-VII shown in FIG. 6. FIG. 7 is a view explaining the operation of a motion guide device according to one embodiment.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Fig. 1 is a perspective view of a motion guide device 1 according to one embodiment. Fig. 2 is an exploded perspective view of the motion guide device 1 according to one embodiment. As shown in Fig. 1, the motion guide device 1 includes an inner ring 10 and an outer ring 20. The inner ring 10 and the outer ring 20 are formed in an annular shape having a common central axis O, and are combined to be capable of relative rotation.

[0014] In the following description, the direction in which the central axis O extends is referred to as the axial direction. The direction perpendicular to the direction in which the central axis O extends is referred to as the radial direction. The direction going around the central axis O is referred to as the circumferential direction.

[0015] The inner ring 10 and the outer ring 20 have a plurality of holes formed in the axial direction. Each of the inner ring 10 and the outer ring 20 is attachable to an object (not shown). The inner ring 10 is configured to be separable into a first ring member 11 and a second ring member 12 in the axial direction. The first ring member 11 and the second ring member 12 are fastened together by bolts (not shown) inserted through some of the plurality of holes.

[0016] As shown in Fig. 2, the motion guide device 1 includes a plurality of rolling elements 30 interposed between the inner ring 10 and the outer ring 20, and a radial retainer 40 and an axial retainer 50 that hold the plurality of rolling elements 30. The rolling elements 30 are cylindrical rollers. In this embodiment, the plurality of rolling elements 30 are provided in three rows between the inner ring 10 and the outer ring 20.

[0017] 3 is an enlarged cross-sectional view of a main part of the motion guide device 1 according to one embodiment. As shown in FIG. 3, a flange 21 protruding radially inward (toward the right side of the drawing) is provided on the inner wall surface of the outer ring 20. The flange 21 is formed in an annular shape.

[0018] A rolling surface 21a of the rolling element 30 is formed on the tip surface of the flange 21 facing inward in the radial direction (to the right side of the drawing). A rolling surface 12a is formed on the second ring member 12, facing the rolling surface 21a of the flange 21 with a gap in the radial direction. The rolling surface 12a is formed below the mating surface 13 of the first ring member 11 and the second ring member 12.

[0019] A plurality of first rolling elements 31 that receive a radial load are disposed between the rolling surfaces 21 a and 12 a. The first rolling elements 31 have rotation axes that extend in the axial direction and roll in the circumferential direction while their peripheral surfaces are in contact with at least one of the rolling surfaces 21 a and 12 a.

[0020] The radial retainer 40 has a plurality of partition walls 41 arranged between the plurality of first rolling elements 31, and a pair of bands 42, 43 that circumferentially connect the plurality of partition walls 41. The radial retainer 40 prevents the first rolling elements 31 from contacting each other and controls the attitude of the first rolling elements 31.

[0021] Furthermore, rolling surfaces 21b of the rolling elements 30 are formed on the surfaces of the flange 21 facing both axial sides (upper and lower sides of the paper). The first ring member 11 is formed with a first opposing flange 14 that faces the flange 21 across a gap in the axial direction. The first opposing flange 14 is formed with a rolling surface 14a that faces the rolling surface 21b of the flange 21 across a gap in the axial direction.

[0022] A plurality of second rolling elements 32 that receive an axial load are disposed between the rolling surfaces 21 b and 14 a. The second rolling elements 32 have rotation axes that extend in the radial direction and roll in the circumferential direction while their peripheral surfaces are in contact with at least one of the rolling surfaces 21 b and 14 a.

[0023] The axial retainer 50 has a plurality of partition walls 51 arranged between the plurality of second rolling elements 32, and a pair of bands 52, 53 that circumferentially connect the plurality of partition walls 51. The axial retainer 50 prevents the second rolling elements 32 from contacting each other and controls the attitude of the second rolling elements 32.

[0024] The second ring member 12 is formed with a second opposing flange 15 that faces the flange 21 across a gap in the axial direction. The second opposing flange 15 is formed with a rolling surface 15a that faces the rolling surface 21b of the flange 21 across a gap in the axial direction. Between the rolling surfaces 21b and 15a, a plurality of second rolling elements 32 are arranged that are held by the axial retainer 50 and receive an axial load, similar to the plurality of second rolling elements 32 between the rolling surfaces 21b and 14a.

[0025] Fig. 4 is a plan view of an axial retainer 50 according to one embodiment. Fig. 5 is a cross-sectional view taken along line VV of Fig. 4. As shown in Fig. 4, the axial retainer 50 is formed by connecting arc-shaped retainer members 50a in an annular shape. The retainer members 50a are, for example, resin-molded parts.

[0026] The bands 52, 53 of the axial retainer 50 are disposed on both radial sides of the multiple partition walls 51. As shown in Fig. 5, the bands 52, 53 are disposed substantially point-symmetrically with respect to the center of the partition wall 51. By arranging the bands 52, 53 in this manner, the molding die (not shown) for the retainer member 50a can be removed in the axial direction (the vertical direction on the paper).

[0027] Of the bands 52, 53, the radial dimension of the band 53 arranged on the radial retainer 40 side (right side of the drawing) is smaller than the radial dimension of the band 52 arranged on the opposite side (left side of the drawing) from the radial retainer 40. Specifically, the radial dimension L21 of the band 53 is about 1 / 2 to 2 / 3 of the radial dimension L11 of the band 52.

[0028] On the other hand, the axial dimension L22 of band 53 is larger than the axial dimension L12 of band 52. This is to make the cross-sectional area of ​​band 53 approximately equal to the cross-sectional area of ​​band 52. By making the cross-sectional areas of bands 52, 53 approximately equal, the strength of bands 52, 53 is made approximately uniform, eliminating problems such as only one band breaking when subjected to a tensile load, for example. Note that "approximately equal" here means that the difference in the cross-sectional areas of bands 52, 53 is within a range of ±5%, preferably ±3%, and more preferably ±1%.

[0029] A plurality of protrusions 54 are formed on the end faces of both axial sides (upper and lower sides in the drawing) of the partition wall 51. The protrusions 54 are formed in a hemispherical shape. A pair of protrusions 54 is provided with a gap in the radial direction. The protrusions 54 make point contact with the rolling surfaces 21b, 14a, 15a, and suppress heat generation due to wear and friction of the axial retainer 50. Note that if there is only one protrusion 54, the axial retainer 50 may tilt around that protrusion 54. Therefore, it is preferable to have two or more protrusions 54.

[0030] Fig. 6 is a plan view of a radial retainer 40 according to one embodiment. Fig. 7 is a cross-sectional view taken along line VII-VII shown in Fig. 6. As shown in Fig. 6, the radial retainer 40 is formed by connecting arc-shaped retainer members 40a in an annular shape. The retainer members 40a are, for example, resin-molded parts.

[0031] 7, the bands 42, 43 of the radial retainer 40 are disposed on both axial sides (upper and lower sides on the paper) of the multiple partition walls 41. The bands 42, 43 are disposed offset in the radial direction. Specifically, the band 43 is disposed in the center of the partition wall 41 in the radial direction. The band 42 is disposed on the axial retainer 50 side of the partition wall 41 in the radial direction (left side on the paper).

[0032] The radial dimension L3 and cross-sectional area of ​​the bands 42, 43 are equal to each other. This allows the strength of the bands 42, 43 to be uniform. Meanwhile, the bands 42, 43 are offset in the radial direction by a dimension L4 that is greater than the dimension L3. By arranging the bands 42, 43 in this manner, the molding die (not shown) for the retainer member 40a can be removed in the axial direction (up and down on the paper).

[0033] FIG. 8 is a diagram illustrating the operation of the motion guide device 1 according to one embodiment. As shown in FIG. 8 , the radial retainer 40 is formed so that the bands 42, 43 alternate in the radial direction due to the molding process described above. Furthermore, when the bands 52, 53 of the axial retainer 50 are arranged point-symmetrically with respect to the center of the partition wall 41, as in this embodiment, if the bands 52, 53 are symmetrical, as indicated by the two-dot chain line in FIG. 8 , there is a possibility that the axial retainer 50 and the radial retainer 40 will interfere with each other. For this reason, in this embodiment, the bands 52, 53 are asymmetrical. As a result, the radial dimension of the band 53 arranged on the radial retainer 40 side is smaller than the radial dimension of the band 52 arranged on the opposite side of the radial retainer 40. This makes it possible to avoid interference between the axial retainer 50 and the radial retainer 40.

[0034] As described above, the motion guide device 1 of this embodiment includes the inner ring 10, the outer ring 20, a plurality of rolling elements 30 interposed between the inner ring 10 and the outer ring 20, and a retainer that holds the plurality of rolling elements 30. The retainer has a plurality of partition walls arranged between the plurality of rolling elements 30 and a pair of bands that connect the plurality of partition walls in the circumferential direction. The retainer includes a radial retainer 40 that holds a plurality of first rolling elements 31 that receive a load in the radial direction among the plurality of rolling elements 30, and a pair of bands that connect the plurality of partition walls in the circumferential direction. and an axial retainer 50 that holds a plurality of second rolling elements 32 that receive a load, a pair of bands 52, 53 of the axial retainer 50 being arranged on both radial sides of a plurality of partition walls 51 of the axial retainer 50, and the radial dimension of one of the pair of bands 52, 53 of the axial retainer 50 that is arranged on the radial retainer 40 side is smaller than the radial dimension of the other band 52 that is arranged on the opposite side of the radial retainer 40. With this configuration, interference between the radial retainer 40 and the axial retainer 50 can be avoided.

[0035] In this embodiment, the cross-sectional area of ​​one band 53 is approximately equal to the cross-sectional area of ​​the other band 52. This configuration makes the strength of the bands 52 and 53 approximately uniform, eliminating problems such as only one band breaking when subjected to a tensile load, for example.

[0036] In this embodiment, at least one of the partition walls 51 of the axial retainer 50 has a plurality of protrusions 54 on its axial end surface. With this configuration, the protrusions 54 come into point contact with the rolling surfaces 21 b, 14 a, 15 a, thereby suppressing heat generation due to wear and friction of the axial retainer 50.

[0037] In addition, in this embodiment, the pair of bands 42, 43 of the radial retainer 40 are disposed on both axial sides of the multiple partition walls 41 of the radial retainer 40 and are disposed offset in the radial direction. With this configuration, the molding die used to mold the radial retainer 40 can be removed in the axial direction.

[0038] While the preferred embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the above-described embodiments. The shapes and combinations of the components shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0039] According to the present invention, interference between the radial retainer and the axial retainer can be avoided.

[0040] DESCRIPTION OF SYMBOLS 1 Motion guide device 10 Inner ring 11 First ring member 12 Second ring member 12a Rolling surface 13 Mating surface 14 First opposing flange 14a Rolling surface 15 Second opposing flange 15a Rolling surface 20 Outer ring 21 Flange 21a Rolling surface 21b Rolling surface 30 Rolling element 31 First rolling element 32 Second rolling element 40 Radial retainer 40a Retainer member 41 Partition wall 42 Band 43 Band 50 Axial retainer 50a Retainer member 51 Partition wall 52 Band 53 Band 54 Protrusion L3 Dimension L4 Dimension L11 Dimension L12 Dimension L21 Dimension L22 Dimension O Central axis

Claims

1. A motion guide device comprising: an inner ring; an outer ring; a plurality of rolling elements interposed between the inner ring and the outer ring; and a retainer that holds the plurality of rolling elements, wherein the retainer has a plurality of partition walls arranged between the plurality of rolling elements; and a pair of bands that circumferentially connect the plurality of partition walls, wherein the retainer comprises a radial retainer that holds a plurality of first rolling elements that receive a radial load among the plurality of rolling elements, and an axial retainer that holds a plurality of second rolling elements that receive an axial load, wherein the pair of bands of the axial retainer are arranged on both radial sides of the plurality of partition walls of the axial retainer, and wherein the radial dimension of one of the pair of bands of the axial retainer that is arranged on the radial retainer side is smaller than the radial dimension of the other band that is arranged on the opposite side of the radial retainer.

2. The motion guide device according to claim 1, wherein the cross-sectional area of ​​said one band is substantially equal to the cross-sectional area of ​​said other band.

3. A motion guide device according to claim 1 or 2, wherein at least one of the plurality of partition walls of the axial retainer has a plurality of protrusions on an end surface in the axial direction.

4. A motion guide device according to claim 1 or 2, wherein the pair of bands of the radial retainer are arranged on both sides of the plurality of partition walls of the radial retainer in the axial direction and are arranged offset in the radial direction.

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