JP2023022891A - Bearing and reduction gear - Google Patents

Abstract

To provide a bearing which allows size reduction of a device having a plurality of different rotating shafts in an axial direction.SOLUTION: A bearing comprises: a first bearing ring having a first raceway surface at an internal peripheral face; a second bearing ring which has a second raceway surface opposing the first raceway surface in a radial direction at an external peripheral face, in which a plurality of first penetration holes are formed while being aligned in a circumferential direction, and which has a plurality of third raceway surfaces surrounding the plurality of first penetration holes; a plurality of third bearing rings having fourth raceway surfaces opposing the third raceway surfaces in the radial direction at external peripheral faces; a plurality of first rolling bodies arranged on a circular ring-shaped raceway along the first raceway surface and the second raceway surface; and a plurality of second rolling bodies arranged on a circular ring-shaped raceway along the third raceway surface and the fourth raceway surface. The first bearing ring includes a pair of circular ring-shaped first steel plates which are arranged while being superimposed on one another in an axial direction. The second bearing ring includes a pair of circular ring-shaped second steel plates which are arranged while being superimposed on one another in the axial direction. The third bearing ring includes a pair of circular ring-shaped third steel plates which are arranged while being superimposed on one another in the axial direction.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present disclosure relates to a bearing and a speed reducer including the same.

2. Description of the Related Art Conventionally, reduction gears having a planetary gear mechanism are known. Techniques of this type are disclosed in Patent Documents 1 and 2, for example.

In the planetary gear reducer disclosed in Patent Document 1, a bearing that rotatably supports the planetary gear with respect to the planetary carrier and a bearing that rotatably supports the planetary carrier with respect to the internal gear are arranged. there is These bearings are arranged side by side in the direction in which the rotating shaft extends in a cross section including the rotating shaft of the speed reducer.

Utility Model Registration No. 2507561 WO2003/050435 WO2021/060489

As described above, in Patent Document 1, the bearings that support the planetary gears and the bearings that support the planetary carrier are arranged side by side in the axial direction. . Therefore, conventionally, there is a problem that it is difficult to miniaturize a device having a plurality of different rotating shafts, such as a planetary gear speed reducer, in the axial direction.

SUMMARY OF THE INVENTION An object of the present disclosure is to provide a bearing and a speed reducer having the same that can axially miniaturize a device having a plurality of different rotating shafts.

A bearing according to the present disclosure includes a first bearing ring having an annular first raceway surface on its inner peripheral surface and an annular second raceway surface radially facing the first raceway surface on its outer peripheral surface. a second bearing ring having a plurality of annular third raceway surfaces surrounding the plurality of first through-holes, a plurality of first through-holes penetrating in the axial direction being formed side by side in a circumferential direction; a plurality of third bearing rings having, on their outer peripheral surfaces, annular fourth raceway surfaces radially opposed to the surfaces; and a plurality of first rolling elements arranged so as to contact the second raceway surface, and contacting the third raceway surface and the fourth raceway surface on an annular raceway along the third raceway surface and the fourth raceway surface and a plurality of second rolling elements arranged as follows. The first bearing ring includes a pair of annular first steel plates that are arranged to overlap in the axial direction. The second bearing ring includes a pair of annular second steel plates that are arranged to overlap in the axial direction. The third bearing ring includes a pair of annular third steel plates that are axially overlapped.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a bearing and a speed reducer including the same that can axially miniaturize a device having a plurality of different rotating shafts.

FIG. 1 is a perspective view showing an external structure of a planetary gear speed reducer according to an embodiment. FIG. 2 is a perspective view showing the internal structure of the planetary gear speed reducer according to the embodiment. FIG. 3 is an exploded perspective view of the planetary gear speed reducer according to the embodiment. FIG. 4 is a cross-sectional view along line IV-IV in FIG. FIG. 5 is an exploded perspective view of the first bearing. FIG. 6 is an exploded perspective view of the third bearing ring. FIG. 7 is a perspective view for explaining attachment of the second bearing ring to the first fixed plate. FIG. 8 is a perspective view showing a usage example of the planetary gear speed reducer according to the embodiment.

[Overview of embodiment]
A bearing according to the present disclosure includes a first bearing ring having an annular first raceway surface on its inner peripheral surface and an annular second raceway surface radially facing the first raceway surface on its outer peripheral surface. a second bearing ring having a plurality of annular third raceway surfaces surrounding the plurality of first through-holes, a plurality of first through-holes penetrating in the axial direction being formed side by side in a circumferential direction; a plurality of third bearing rings having, on their outer peripheral surfaces, annular fourth raceway surfaces radially opposed to the surfaces; and a plurality of first rolling elements arranged so as to contact the second raceway surface, and contacting the third raceway surface and the fourth raceway surface on an annular raceway along the third raceway surface and the fourth raceway surface and a plurality of second rolling elements arranged as follows. The first bearing ring includes a pair of annular first steel plates that are arranged to overlap in the axial direction. The second bearing ring includes a pair of annular second steel plates that are arranged to overlap in the axial direction. The third bearing ring includes a pair of annular third steel plates that are axially overlapped.

According to the above bearing, by arranging the third bearing ring axially overlapping the first rotating member (for example, the planetary gear in the planetary gear speed reducer) and fixing it to the first rotating member, the As the first rotating member rotates, the third bearing ring rotates in the circumferential direction relative to the second bearing ring via the second rolling elements. On the other hand, the third bearing ring revolves along with the revolution of the first rotating member, and the second bearing ring is pushed in the circumferential direction by the third bearing ring, thereby pushing the second bearing ring through the first rolling element. It rotates in the circumferential direction relative to the first bearing ring. According to the above bearing, the rolling elements (second rolling elements) for rotating the third bearing ring in the circumferential direction with respect to the second bearing ring and the second bearing ring are rotated in the circumferential direction with respect to the first bearing ring. A rolling element (first rolling element) for rotating is positioned on the same plane perpendicular to the rotation axis. Therefore, according to the above bearing, it is possible to reduce the size of a device having a plurality of different rotating shafts in the axial direction, compared to the conventional device. Moreover, since the first to third bearing rings each include a pair of steel plates that are superimposed in the axial direction, the bearing can be manufactured more easily.

In the above bearing, at least one of the pair of first steel plates, the pair of second steel plates, and the pair of third steel plates may be fixed to each other by fitting the convex portion and the concave portion. According to this configuration, the pair of steel plates can be temporarily fixed together when assembling the bearing.

In the above-described bearing, a fixed plate arranged so as to overlap the second bearing ring in the axial direction; and a bolt having a male thread formed on its surface. The second bearing ring may be formed with a third through hole that penetrates in the axial direction and into which the shaft portion is inserted. The fixing plate may be formed with a female screw hole into which the shaft portion is inserted and which meshes with the male screw.

When forming a female threaded hole in the second steel sheet itself, if the female threaded hole is formed in the second steel sheet before quenching, the shape of the female thread may change after quenching and may not mesh with the male thread of the fixing bolt. On the other hand, since the second steel plate after quenching has high hardness, it is difficult to form a female screw hole. On the other hand, by arranging the fixing plate having the female threaded hole over the second bearing ring, the separation of the pair of second steel plates can be prevented without forming the female threaded hole in the second steel plate itself. can be suppressed.

In the bearing described above, the second bearing ring may be formed with a second through hole penetrating in the axial direction radially inward of the plurality of first through holes. The second bearing ring may have an annular fifth raceway surface surrounding the second through hole. The bearing includes a fourth raceway ring having an annular sixth raceway surface radially opposed to the fifth raceway surface on its outer peripheral surface, and an annular raceway along the fifth raceway surface and the sixth raceway surface. and a plurality of third rolling elements arranged to contact the fifth raceway surface and the sixth raceway surface. The fourth bearing ring may include a pair of annular fourth steel plates that are arranged to overlap in the axial direction. According to this configuration, by arranging the fourth bearing ring axially overlapping the second rotating member (for example, the sun gear of the planetary gear speed reducer) and fixing it to the second rotating member, As the second rotating member rotates, the fourth bearing ring can be relatively rotated in the circumferential direction with respect to the second bearing ring via the third rolling element.

A speed reducer according to the present disclosure includes a sun gear having a plurality of external teeth arranged circumferentially on an outer peripheral surface, and arranged side by side in the circumferential direction so as to surround the sun gear, and arranged along the outer peripheral surface along the circumferential direction. a planetary gear having a plurality of external teeth that mesh with the plurality of external teeth of the sun gear; and an annular internal gear formed with a space for housing the planetary gear, and a first bearing and a second bearing that axially sandwich the internal gear. The first bearing and the second bearing are the bearings described above. The fourth orbital ring is fixed to the sun gear so that the sun gear and the rotation axis coincide with each other. The third bearing ring is fixed to the planetary gears so that the planetary gears and the rotating shaft are aligned with each other. The first bearing ring is fixed to the internal gear so that the center axis of the first bearing ring coincides with the internal gear.

According to the speed reducer, the third bearing ring rotates in the circumferential direction relative to the second bearing ring via the second rolling element as the planetary gear rotates. On the other hand, the third bearing ring revolves along with the revolution of the planetary gear, and the second bearing ring is pushed in the circumferential direction by the third bearing ring, so that the second bearing ring moves toward the first raceway via the first rolling elements. It rotates in the circumferential direction relative to the wheel. That is, the second race rotates as a planetary carrier (output shaft). In the reduction gear described above, the second rolling elements for rotating the planetary gears and the first rolling elements for rotating the planetary carrier (second bearing ring) are positioned on the same plane perpendicular to the rotation axis. Therefore, the size can be reduced in the axial direction as compared with the conventional planetary gear speed reducer.

The speed reducer includes an annular first spacer arranged between the third bearing ring of the first bearing and the planetary gear, and an annular spacer arranged between the third bearing ring of the second bearing and the planetary gear. and a second spacer. According to this configuration, the deformation of the third steel plate inward in the axial direction can be suppressed by the first and second spacers.

The speed reducer may further include a third spacer arranged between the second bearing ring of the first bearing and the second bearing ring of the second bearing. According to this configuration, the third spacer can suppress the axially inward deformation of the second steel plate.

[Specific example of embodiment]
Next, specific embodiments of the speed reducer and the bearing of the present disclosure will be described with reference to the drawings. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

First, the configurations of the speed reducer and bearings according to the present embodiment will be described with reference to FIGS. 1 to 8. FIG. FIG. 1 is a perspective view showing the external structure of a speed reducer 100 according to this embodiment. FIG. 2 is a perspective view showing the internal structure of the speed reducer 100. As shown in FIG. FIG. 3 is an exploded perspective view of the reduction gear 100. FIG. FIG. 4 is a cross-sectional view of speed reducer 100 taken along line IV-IV in FIG. FIG. 5 is an exploded perspective view of a bearing (first bearing 1) according to this embodiment. 6 is an exploded perspective view of the third bearing ring 30 of the first bearing 1. FIG.

The speed reducer 100 is a speed reducer with a planetary gear mechanism. As shown in FIG. 3, the speed reducer 100 includes a sun gear 3, a plurality of (three in the present embodiment) planetary gears 4, an internal gear 5, a first bearing 1, a second bearing 2, and a is mainly provided. Each of these components will be described in detail below.

The sun gear 3 has a cylindrical shape and has a plurality of external teeth 3A arranged along the circumferential direction on its outer peripheral surface (FIG. 2). As shown in FIG. 4, the sun gear 3 is arranged at the center in the radial direction D2 such that the central axis C1 of the speed reducer 100 passes through the hollow portion 3B. The cylindrical portion of the sun gear 3 extends outside the outer surface of the second bearing 2 in the axial direction D1 in the axial direction D1. The shape and number of the external teeth 3A are not particularly limited.

As shown in FIG. 3 , the plurality of planetary gears 4 are arranged side by side in the circumferential direction so as to surround the sun gear 3 . More specifically, in the present embodiment, the plurality of planetary gears 4 are arranged at equal intervals (at intervals of 120°) in the circumferential direction. The planetary gear 4 has an annular shape with a larger diameter than the sun gear 3, and has a plurality of external teeth 4A arranged along the circumferential direction on its outer peripheral surface (FIG. 2). As shown in FIG. 2, the plurality of external teeth 3A of the sun gear 3 and the plurality of external teeth 4A of the planetary gear 4 mesh with each other. The shape and number of the external teeth 4A are not particularly limited, and the number of planetary gears is also not particularly limited.

As shown in FIG. 2 , the internal gear 5 is an annular member having a space for accommodating the sun gear 3 and the plurality of planetary gears 4 . As shown in FIG. 4, the length of the internal gear 5 in the axial direction D1 is substantially the same as the length of the planetary gear 4 in the axial direction D1. As shown in FIG. 2, the internal gear 5 has a plurality of internal teeth 5A arranged along the circumferential direction on the inner peripheral surface. The plurality of external teeth 4A of the planetary gear 4 and the plurality of internal teeth 5A of the internal gear 5 mesh with each other. As shown in FIG. 3, the internal gear 5 is formed with a plurality of through holes 5B penetrating in the axial direction D1 at intervals in the circumferential direction. The internal gear 5 constitutes a gear portion in the speed reducer 100 together with the sun gear 3 and the plurality of planetary gears 4 . The shape and number of the internal teeth 5A are not particularly limited.

As shown in FIG. 3, the internal gear 5 has substantially the same diameter as the first bearing 1 and the second bearing 2, and is sandwiched between the first bearing 1 and the second bearing 2 in the axial direction D1. Here, the configurations of the first bearing 1 and the second bearing 2 will be described in detail.

FIG. 1 is a perspective view of the speed reducer 100 viewed from the first bearing 1 side. As shown in FIG. 1, the first bearing 1 includes a first bearing ring 10, a second bearing ring 20, a plurality of (three in the present embodiment) third bearing rings 30, and a fourth bearing ring 40. including. The first bearing ring 10 has an annular shape, and is formed with a plurality of axially penetrating through holes spaced apart in the circumferential direction. The first bearing ring 10 has an annular first raceway surface 11A on its inner peripheral surface. The first bearing ring 10 is fixed to the internal gear 5 so that the center axis of the first bearing ring 10 is aligned with the internal gear 5 .

As shown in FIG. 5 , the first bearing ring 10 includes a pair of annular first steel plates 11 that are stacked in the axial direction D1. The first steel plate 11 is a thin steel plate formed by press forming. The pair of first steel plates 11 have substantially the same outer diameter and inner diameter, and are fixed to each other by fitting the convex portion and the concave portion. Specifically, as shown in FIG. 5, a columnar protrusion 81A protruding in the axial direction D1 toward the other first steel plate 11 is formed on the end face of one of the first steel plates 11 facing in the axial direction D1. formed. On the other hand, the other first steel plate 11 is formed with a recess 82A (circular through hole when viewed in the axial direction D1) into which the protrusion 81A is fitted. As shown in FIG. 4, the inner peripheral surface of the first steel plate 11 is an arc-shaped curved surface in a cross section including the central axis C1, and constitutes the first raceway surface 11A. Here, since the ends of the grain flows are not exposed on the first raceway surface 11A, the strength of the first raceway surface 11A is high. The number of first steel plates 11 forming first bearing ring 10 may be three or more.

As shown in FIG. 1, the second bearing ring 20 is an annular member having an outer diameter smaller than the inner diameter of the first bearing ring 10, and is arranged radially inward of the first bearing ring 10. there is The second raceway ring 20 has an annular second raceway surface 21A on its outer peripheral surface, which radially faces the first raceway surface 11A. In the second raceway surface 21A, the end of the grain flow is not exposed in the same manner as in the first raceway surface 11A.

A plurality of (three in the present embodiment) first through-holes 81 are formed side by side in the circumferential direction in the second bearing ring 20 so as to penetrate in the axial direction D1. The first through hole 81 is a circular hole when viewed in the axial direction D1, and the third bearing ring 30 is arranged. The second bearing ring 20 has a plurality (three in the present embodiment) of annular third raceway surfaces 21B surrounding the plurality of first through holes 81 . The ends of grain flows are not exposed on the third raceway surface 21B, similarly to the first and second raceway surfaces. The number of first through holes 81 is the same as the number of planetary gears 4 .

As shown in FIG. 1 , the second bearing ring 20 is formed with second through holes 82 penetrating in the axial direction D<b>1 radially inward of the plurality of first through holes 81 . More specifically, the second through hole 82 is a circular hole when viewed in the axial direction D1, and the center axis C1 (FIG. 4) passes through the center thereof. The second through hole 82 has a diameter smaller than that of the first through hole 81, and the fourth bearing ring 40 is arranged therein. The second bearing ring 20 has an annular fifth raceway surface 21</b>C surrounding the second through hole 82 . The ends of grain flows are not exposed on the fifth raceway surface 21C, similarly to the first to fourth raceway surfaces.

As shown in FIG. 5 , the second bearing ring 20 includes a pair of annular second steel plates 21 stacked in the axial direction D1. The second steel plate 21, like the first steel plate 11, is a thin steel plate formed by press forming. Holes corresponding to the first through hole 81 and the second through hole 82 (FIG. 1) are formed in the second steel plate 21 respectively.

The pair of second steel plates 21 have substantially the same outer diameter, and are fixed to each other by fitting the convex portion and the concave portion in the same manner as the pair of first steel plates 11 . That is, as shown in FIG. 5, the main surface of one second steel plate 21 is formed with a cylindrical projection 83A that protrudes in the axial direction D1 toward the other second steel plate 21 . On the other hand, the other second steel plate 21 is formed with a recess 84 (a circular through hole when viewed in the axial direction D1) in which the protrusion 83A is fitted. The number of second steel plates 21 forming the second bearing ring 20 may be three or more.

The first bearing 1 further includes a plurality of first rolling elements 51 arranged on annular raceways along the first raceway surface 11A and the second raceway surface 21A (FIGS. 4 and 5). The first rolling elements 51 in the present embodiment are balls, for example, and are in contact with the first raceway surface 11A and the second raceway surface 21A, respectively. As a result, the first bearing ring 10 and the second bearing ring 20 are relatively rotatable in the circumferential direction around the central axis C<b>1 via the plurality of first rolling elements 51 . Note that the first rolling element is not limited to a ball, and may be another rolling element such as a cylindrical roller.

As shown in FIG. 1 , the third bearing ring 30 is an annular member having a diameter smaller than that of the second bearing ring 20 and is arranged in each of the plurality of first through holes 81 . The third raceway ring 30 has an annular fourth raceway surface 30A radially facing the third raceway surface 21B of the second raceway ring 20 on its outer peripheral surface. The ends of grain flows are not exposed on the fourth raceway surface 30A, similarly to the first to third raceway surfaces. The third bearing ring 30 is fixed to the planetary gear 4 so that the rotation axis of the planetary gear 4 coincides with that of the planetary gear 4 .

As shown in FIG. 6 , the third bearing ring 30 includes a pair of annular third steel plates 31 stacked in the axial direction D1. The third steel plate 31 is formed by press forming in the same manner as the first and second steel plates. Like the first steel plate 11 and the second steel plate 21, the third steel plate 31 is fixed to each other by fitting the convex portion and the concave portion. Specifically, as shown in FIG. 6, the main surface of one third steel plate 31 is formed with a columnar projection 85 that protrudes in the axial direction D1 toward the other third steel plate 31. . On the other hand, the other third steel plate 31 is formed with a concave portion 86 (circular through hole when viewed in the axial direction D1) in which the convex portion 85 is fitted. The number of the third steel plates 31 forming the third bearing ring 30 may be three or more.

The first bearing 1 includes a plurality of second rolling elements 52 arranged on an annular raceway along the third raceway surface 21B and the fourth raceway surface 30A (Figs. 4 and 5). The second rolling elements 52 in the present embodiment are balls, for example, and are in contact with the third raceway surface 21B and the fourth raceway surface 30A, respectively. Thereby, the second bearing ring 20 and the third bearing ring 30 are relatively rotatable in the circumferential direction via the plurality of second rolling elements 52 . This rotation axis does not coincide with the rotation axis (central axis C1) when the first bearing ring 10 and the second bearing ring 20 rotate relatively in the circumferential direction. In addition, the second rolling element is not limited to a ball, and may be another rolling element such as a cylindrical roller.

As shown in FIG. 1 , the fourth bearing ring 40 is an annular member having a smaller diameter than the third bearing ring 30 and is arranged in the second through hole 82 . The fourth bearing ring 40 has an annular sixth raceway surface 41</b>A on its outer peripheral surface, which radially faces the fifth raceway surface 21</b>C of the second bearing ring 20 . The grain flows are not exposed on the sixth raceway surface 41A, similarly to the first to fifth raceway surfaces. The fourth orbital ring 40 is fixed to the sun gear 3 so that the sun gear 3 and the rotating shaft are aligned with each other. As shown in FIG. 5 , the fourth bearing ring 40 includes a pair of annular fourth steel plates 41 stacked in the axial direction D1. The fourth steel plate 41 is formed by press forming in the same manner as the first to third steel plates.

The first bearing 1 includes a plurality of third rolling elements 53 arranged on an annular raceway along the fifth raceway surface 21C and the sixth raceway surface 41A (FIGS. 4 and 5). The third rolling elements 53 in the present embodiment are balls, for example, and are in contact with the fifth raceway surface 21C and the sixth raceway surface 41A, respectively. As a result, the second bearing ring 20 and the fourth bearing ring 40 are relatively rotatable in the circumferential direction around the central axis C1 (FIG. 4) via the plurality of third rolling elements 53 . In addition, the third rolling element is not limited to a ball, and may be another rolling element such as a cylindrical roller.

The second bearing 2 has the same structure as the first bearing 1 except that the fourth bearing ring 40 and the third rolling elements 53 are not provided. Therefore, detailed description of the configuration of the second bearing 2 is omitted.

As shown in FIG. 4 , the speed reducer 100 further includes a first spacer 63 , a second spacer 64 and a first fixing member 66 . The first spacer 63 is an annular member and is arranged between the third bearing ring 30 of the first bearing 1 and the planetary gear 4 in the axial direction D1. The first spacer 63 is in contact with the surface of the third bearing ring 30 (the third steel plate 31) of the first bearing 1 that faces the planetary gear 4 side, and the surface of the planetary gear 4 that faces the first bearing 1 side. in contact.

The second spacer 64 is an annular member having approximately the same size as the first spacer 63, and is arranged between the third bearing ring 30 of the second bearing 2 and the planetary gear 4 in the axial direction D1. . The second spacer 64 contacts the surface of the third bearing ring 30 (the third steel plate 31) of the second bearing 2 that faces the planetary gear 4 side, and the surface of the planetary gear 4 that faces the second bearing 2 side. in contact. As shown in FIG. 3, the first spacers 63 and the second spacers 64 are arranged in plural (three in this embodiment) at regular intervals (120° intervals) in the circumferential direction. The number of first spacers 63 and second spacers 64 is the same as the number of planetary gears 4 .

As shown in FIG. 4, the first fixing member 66 includes a first bolt 66A and a first female screw member 66B. The first bolt 66A has a shaft extending in the axial direction D1 and a head extending in the radial direction D2 from the end of the shaft (the left end in FIG. 4) and in contact with the outer surface of the first bearing 1 in the axial direction D1. including the part. A male thread is formed on the outer peripheral surface of the shaft portion. The first bolt 66A extends through the center hole of the third bearing ring 30 of the first bearing 1, the center hole of the first spacer 63, the center hole of the planetary gear 4, the center hole of the second spacer 64 and the third bolt of the second bearing 2. It is inserted into each of the central holes of the bearing ring 30 .

As shown in FIG. 4, the first female screw member 66B includes a cylindrical portion extending in the axial direction D1 and a flange portion extending in the radial direction D2 from the end (right end in FIG. 4) of the cylindrical portion. The cylindrical portion is inserted into the center hole of the third bearing ring 30 of the second bearing 2, the center hole of the second spacer 64, the center hole of the planetary gear 4, and the center hole of the first spacer 63, respectively.

A female screw is formed on the inner peripheral surface of the cylindrical portion of the first female screw member 66B. As shown in FIG. 4, the shaft portion of the first bolt 66A is inserted inside the cylindrical portion of the first female threaded member 66B, and the male thread formed on the outer peripheral surface of the shaft portion extends to the inner periphery of the cylindrical portion. It meshes with internal threads formed in the face.

As shown in FIG. 4, the speed reducer 100 further includes a third spacer 65. As shown in FIG. The third spacer 65 has an annular shape, and provides a space between the second bearing ring 20 (second steel plate 21) of the first bearing 1 and the second bearing ring 20 (second steel plate 21) of the second bearing 2. placed in between. More specifically, one end surface of the third spacer 65 in the axial direction D1 is in contact with the inner surface of the second bearing ring 20 (second steel plate 21) of the first bearing 1. The other end surface in the axial direction D1 is in contact with the inner surface of the second bearing ring 20 (second steel plate 21) of the second bearing 2. As shown in FIG.

A third female screw member 67 is inserted into the third spacer 65 . The third female threaded member 67 is a member for attaching the mating member 90 to the speed reducer 100, and is similar to the first female threaded member 66B.

As shown in FIG. 3 , the speed reducer 100 further includes a first fixed plate 62 and a second fixed plate 68 . The first fixed plate 62 is a disc having a slightly smaller diameter than the second bearing ring 20 of the first bearing 1 . In the first fixing plate 62, a plurality (three in the present embodiment) of first through holes 62A arranged in the circumferential direction and a second through hole 62B surrounded by the plurality of first through holes 62A are formed. It is A first spacer 63 is arranged inside the first through hole 62A. The cylindrical portion of the sun gear 3 is inserted inside the second through hole 62B. As shown in FIG. 4, the first fixed plate 62 is arranged to overlap the second bearing ring 20 (second steel plate 21) of the first bearing 1 in the axial direction D1.

As shown in FIG. 3 , the second fixed plate 68 is a disc similar to the first fixed plate 62 and has a slightly smaller diameter than the second bearing ring 20 of the second bearing 2 . In the second fixing plate 68, a plurality (three in the present embodiment) of first through holes 68A arranged in the circumferential direction and a second through hole 68B surrounded by the plurality of first through holes 68A are formed. It is A second spacer 64 is arranged inside the first through hole 68A. The cylindrical portion of the sun gear 3 is inserted inside the second through hole 68B. As shown in FIG. 4, the second fixed plate 68 is arranged to overlap the second bearing ring 20 (second steel plate 21) of the second bearing 2 in the axial direction D1.

FIG. 7 shows the second bearing ring 20 (the pair of second steel plates 21), the first fixing plate 62, and the plurality of bolts 69 of the first bearing 1, respectively. The bolt 69 is a member for fixing the second bearing ring 20 to the first fixed plate 62 . As shown in FIG. 7, the bolt 69 includes a head portion 69A and a shaft portion 69B extending from the head portion 69A in the axial direction D1. The shaft portion 69B has a cylindrical shape and has a male thread formed on its outer peripheral surface.

A large number of third through holes 83 are formed through the second steel plate 21 in the axial direction D1. The inner peripheral surface surrounding the third through hole 83 is a curved surface without a threaded portion. A shaft portion 69B of the bolt 69 is inserted into the third through hole 83 .

A female screw hole 62C is formed in the first fixing plate 62 at a position overlapping the third through hole 83 in the axial direction D1. The female threaded hole 62C is a portion into which the shaft portion 69B of the bolt 69 is inserted, and meshes with a male thread formed on the outer peripheral surface of the shaft portion 69B.

As shown in FIG. 3 , the speed reducer 100 further includes fifth spacers 61 and sixth spacers 71 . The fifth spacer 61 has an annular shape and has an outer diameter substantially the same as that of the first bearing ring 10 of the first bearing 1 and an inner diameter slightly larger than that of the first bearing ring 10 . The fifth spacer 61 is made of, for example, a press-formed steel plate, and has a plurality of through holes extending in the axial direction D1 arranged in the circumferential direction. As shown in FIG. 4, the fifth spacer 61 is sandwiched between the first bearing ring 10 (first steel plate 11) of the first bearing 1 and the internal gear 5 in the axial direction D1. A first fixing plate 62 is arranged inside the fifth spacer 61 in the radial direction D2.

As shown in FIG. 3 , the sixth spacer 71 is an annular member similar to the fifth spacer 61 . The sixth spacer 71 is sandwiched between the first bearing ring 10 (first steel plate 11) of the second bearing 2 and the internal gear 5 in the axial direction D1 (Fig. 4). A second fixing plate 68 is arranged inside the sixth spacer 71 in the radial direction D2.

As shown in FIG. 4, the speed reducer 100 further includes a plurality of second fixing members 87. As shown in FIG. The second fixing member 87 includes a second bolt 87A and a second female screw member 87B. The second bolt 87A has a shaft extending in the axial direction D1 and a head extending in the radial direction D2 from the end of the shaft (the left end in FIG. 4) and in contact with the outer surface of the first bearing 1 in the axial direction D1. including the part. A male thread is formed on the outer peripheral surface of the shaft portion. The second bolt 87A passes through each of the first bearing ring 10 of the first bearing 1, the fifth spacer 61, the internal gear 5, the sixth spacer 71 and the first bearing ring 10 of the second bearing 2 in the axial direction D1. are doing.

The second female screw member 87B includes a cylindrical portion extending in the axial direction D1 and a flange portion extending in the radial direction D2 from the end portion (right end portion in FIG. 4) of the cylindrical portion. The cylindrical portion penetrates each of the first bearing ring 10, the sixth spacer 71, the internal gear 5 and the fifth spacer 61 of the second bearing 2 in the axial direction D1. As shown in FIG. 4, the shaft portion of the second bolt 87A is inserted inside the cylindrical portion of the second female threaded member 87B, and the male thread formed on the outer peripheral surface of the shaft portion extends to the inner periphery of the cylindrical portion. It meshes with internal threads formed in the face.

Next, functions and effects of the speed reducer 100 and the bearings (first bearing 1 and second bearing 2) according to the present embodiment will be described. As shown in FIG. 4, in the speed reducer 100, the third bearing rings 30 of the first bearing 1 and the second bearing 2 are arranged so as to overlap each other in the axial direction D1 with respect to the planetary gear 4, It is fixed to the planetary gear 4 by a member 66 . For this reason, the sun gear 3 is rotated around the central axis C1 by a drive source (motor) (not shown), and the planetary gears 4 meshing with the sun gear 3 are caused to rotate. , relative to the second bearing ring 20 in the circumferential direction.

On the other hand, as the planetary gear 4 revolves around the central axis C1, the third bearing ring 30 revolves, and the second bearing ring 20 is pushed by the third bearing ring 30 in the circumferential direction. As a result, the second bearing ring 20 rotates in the circumferential direction relative to the first bearing ring 10 via the first rolling elements 51 . That is, the second bearing ring 20 functions as a planetary carrier (output shaft) in the speed reducer 100, and the mating member 90 (FIG. 8) rotates at a lower speed than the motor. In the present embodiment, the rolling elements (second rolling elements 52) for rotating the planetary gear 4 and the rolling elements (first rolling elements 51) for rotating the planetary carrier are connected to the rotating shaft ( located on the same plane perpendicular to the central axis C1) (Fig. 4). Therefore, according to the present embodiment, it is possible to reduce the size of the planetary gear speed reducer in the axial direction D1 as compared with the conventional one.

In addition, although the case where the 1st bearing 1 and the 2nd bearing 2 were used as a component of the reduction gear 100 was demonstrated as an example in the said embodiment, it is not limited to this. The first bearing 1 and the second bearing 2 may be used as constituent members of a device other than the planetary gear speed reducer, which has a plurality of different rotation shafts.

It should be understood that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of equivalence to the scope of claims.

Reference Signs List 1 first bearing 2 second bearing 3 sun gear 3A external tooth 3B hollow portion 4 planetary gear 4A external tooth 5 internal gear 5A internal tooth 5B through hole 10 first bearing ring 11 1st steel plate 11A 1st raceway surface 20 2nd raceway ring 21 2nd steel plate 21A 2nd raceway surface 21B 3rd raceway surface 21C 5th raceway surface 30 3rd raceway ring 30A 4th raceway surface , 31 third steel plate, 40 fourth bearing ring, 41 fourth steel plate, 41A sixth raceway surface, 51 first rolling element, 52 second rolling element, 53 third rolling element, 61 fifth spacer, 62 first fixing plate, 62A first through hole, 62B second through hole, 62C female threaded hole, 63 first spacer, 64 second spacer, 65 third spacer, 66 first fixing member, 66A first bolt, 66B first female threaded member, 67 third female screw member 68 second fixing plate 68A first through hole 68B second through hole 69 bolt 69A head 69B shaft portion 71 sixth spacer 81 first through hole 81A convex portion 82 second through hole, 82A recess, 83 third through hole, 83A protrusion, 84 recess, 85 protrusion, 86 recess, 87 second fixing member, 87A second bolt, 87B second female screw member, 90 mating member, 100 reduction gear, C1 central axis, D1 axial direction, D2 radial direction

Claims (7)

a first bearing ring having an annular first raceway surface on its inner peripheral surface;
An annular second raceway surface radially opposed to the first raceway surface is formed on the outer peripheral surface, and a plurality of first through holes extending axially through the raceway surface are arranged in the circumferential direction. a second bearing ring having a plurality of annular third raceway surfaces surrounding one through hole;
a plurality of third raceway rings each having an annular fourth raceway surface on its outer peripheral surface facing the third raceway surface in the radial direction;
a plurality of first rolling elements arranged on an annular raceway along the first raceway surface and the second raceway surface so as to be in contact with the first raceway surface and the second raceway surface;
a plurality of second rolling elements arranged on an annular orbit along the third raceway surface and the fourth raceway surface so as to be in contact with the third raceway surface and the fourth raceway surface;
The first bearing ring includes a pair of annular first steel plates arranged to overlap in the axial direction,
The second bearing ring includes a pair of annular second steel plates arranged to overlap in the axial direction,
The bearing, wherein the third bearing ring includes a pair of annular third steel plates that are stacked in the axial direction. 2. The bearing according to claim 1, wherein at least one of said pair of first steel plates, said pair of second steel plates, and said pair of third steel plates are fixed to each other by fitting a convex portion and a concave portion. a fixed plate arranged to overlap with the second bearing ring in the axial direction;
a bolt for fixing the second bearing ring to the fixed plate, the bolt having a shaft portion extending in the axial direction and having a male thread formed on an outer peripheral surface of the shaft portion;
The second bearing ring is formed with a third through hole that penetrates in the axial direction and into which the shaft portion is inserted,
3. The bearing according to claim 1, wherein said fixed plate is formed with a female screw hole into which said shaft portion is inserted and which meshes with said male screw. A second through hole penetrating in the axial direction is formed in the second bearing ring inside the plurality of first through holes in the radial direction,
The second bearing ring has an annular fifth raceway surface surrounding the second through hole,
a fourth raceway ring having, on its outer peripheral surface, an annular sixth raceway surface facing the fifth raceway surface in the radial direction;
a plurality of third rolling elements arranged on an annular raceway along the fifth raceway surface and the sixth raceway surface so as to be in contact with the fifth raceway surface and the sixth raceway surface;
4. The bearing according to any one of claims 1 to 3, wherein the fourth bearing ring includes a pair of annular fourth steel plates that are stacked in the axial direction. a sun gear having a plurality of external teeth arranged along the circumferential direction on the outer peripheral surface;
a planetary gear arranged side by side in the circumferential direction so as to surround the sun gear, and having a plurality of external teeth arranged along the circumferential direction on an outer peripheral surface thereof and meshing with the plurality of external teeth of the sun gear;
An annular ring having a plurality of internal teeth arranged along the circumferential direction on its inner peripheral surface and meshing with the plurality of external teeth of the planetary gear, and having a space formed therein for accommodating the sun gear and the planetary gear. an internal gear; and
a first bearing and a second bearing that sandwich the internal gear in the axial direction;
The first bearing and the second bearing are the bearings according to claim 4,
The fourth orbital ring is fixed to the sun gear so that the rotation axis of the sun gear is aligned with the sun gear,
The third bearing ring is fixed to the planetary gear so that the rotation axis of the planetary gear is aligned with the planetary gear,
The speed reducer, wherein the first bearing ring is fixed to the internal gear so that the center axis thereof coincides with the internal gear. an annular first spacer disposed between the third bearing ring of the first bearing and the planetary gear;
6. The speed reducer according to claim 5, further comprising an annular second spacer disposed between said third bearing ring of said second bearing and said planetary gear. 7. The speed reducer according to claim 5, further comprising a third spacer disposed between said second bearing ring of said first bearing and said second bearing ring of said second bearing.

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