JP2021162036A - Planetary gear, planetary reduction gear and manufacturing method of planetary gear - Google Patents

Abstract

To provide a technique which can fix a first planetary gear and a second planetary gear while suppressing a change of tooth shapes of the first planetary gear at the manufacturing of a planetary gear having the first planetary gear and the second planetary gear which is smaller than the first planetary gear in a diameter.SOLUTION: A planetary gear has a first planetary gear and a second planetary gear which is smaller than the first planetary gear in a diameter. The first planetary gear has a first spline at an internal peripheral face. The first spline has a plurality of inner teeth extending in an axial direction. The second planetary gear has a second spline at an external peripheral face. The second spline has a plurality of outer teeth extending in the axial direction. The first spline and the second spline are clearance-fit or transition-fit to each other. The planetary gear has a fixing part at an end face in the axial direction. In the fixing part, a tooth shape cross section of the second spline is larger than a tooth shape cross section of the other portion of the second spline. Also, in the fixing part, the inner teeth and the outer teeth tightly adhere to each other.SELECTED DRAWING: Figure 4

Description

The present invention relates to planetary gears, planetary reducers, and methods for manufacturing planetary gears.

Conventionally, a planetary speed reducer having a sun gear, a plurality of planetary gears arranged around the sun gear, and an internal gear surrounding the plurality of planetary gears is known. In addition, the planetary gear is a two-stage planetary gear composed of two gears with different numbers of teeth, and a differential type planetary reducer that realizes a high reduction ratio by two internal gears that mesh with the two-stage planetary gear is available. Are known.

A conventional differential type planetary reducer is described, for example, in Japanese Patent Application Laid-Open No. 54-183566.
Jikkai Sho 54-183566

The two-stage planetary gear used in the differential type planetary reducer is composed of a first planetary gear and a second planetary gear having a diameter smaller than that of the first planetary gear. At the time of manufacturing the two-stage planetary gear, a part of the second planetary gear is inserted inside the first planetary gear. At that time, the spline provided on the outer peripheral surface of the second planetary gear is fitted to the spline provided on the inner peripheral surface of the first planetary gear. This regulates the rotation of the second planetary gear with respect to the first planetary gear.

However, if the spline of the first planetary gear and the spline of the second planetary gear are inserted by a gap fit, the first planetary gear cannot be fixed to the second planetary gear in the axial direction. On the other hand, when the spline of the second planetary gear is press-fitted into the spline of the first planetary gear, there is a problem that the first planetary gear is distorted and the tooth profile of the first planetary gear is changed.

An object of the present invention is to suppress changes in the tooth profile of the first planetary gear during the manufacture of a planetary gear having a first planetary gear and a second gear having a diameter smaller than that of the first planetary gear, and the first planet. It is to provide a technique capable of fixing a gear and a second planetary gear.

The first invention of the present application is a planetary gear used in a planetary speed reducer, which is an annular first planetary gear and a second planetary gear fixed to the first planetary gear and having a diameter smaller than that of the first planetary gear. The first planetary gear has a planetary gear, and the first planetary gear has a first spline having a plurality of internal teeth extending in the axial direction on the inner peripheral surface, and the second planetary gear has an axial direction on the outer peripheral surface. It has a second spline having a plurality of external teeth extending to, and the first spline and the second spline are fitted by a gap fit or an intermediate fit, and on an axial end face, the first spline and the first spline. It has one or more fixing portions at the boundary with the second spline, and in the fixing portion, the tooth profile cross section of the second spline is larger than the tooth profile cross section of the other portion of the second spline. In the fixed portion, the internal teeth and the external teeth are in close contact with each other.

The second invention of the present application is a planetary gear used in a planetary speed reducer, which is an annular first planetary gear and a second planetary gear fixed to the first planetary gear and having a diameter smaller than that of the first planetary gear. The first planetary gear has a planetary gear, and the first planetary gear has a first spline having a plurality of internal teeth extending in the axial direction on the inner peripheral surface, and the second planetary gear has an axial direction on the outer peripheral surface. It has a second spline having a plurality of external teeth extending to, and the first spline and the second spline are fitted by a gap fit or an intermediate fit, and on an axial end face, the first spline and the first spline. It has one or more fixing portions at the boundary with the second spline, and in the fixing portion, the first gap between the tooth tip of the first spline and the tooth bottom of the second spline is the other. The second gap between the root of the first spline and the tip of the second spline is smaller than the first gap of the first spline, or smaller than the other second gap of the second spline. The internal teeth and the external teeth are in close contact with each other.

A third invention of the present application is a method for manufacturing a planetary gear according to the first invention or the second invention. A) The second spline of the second planetary gear is inside the first spline of the first planetary gear. B) The step of forming the fixed portion by caulking the boundary between the first spline and the second spline in the axial direction at the end face of the planetary gear.

The fourth invention of the present application is the method for manufacturing a planetary gear of the first invention or the second invention, and a) the second spline of the second planetary gear inside the first spline of the first planetary gear. B) The step of forming the fixed portion by crimping the external teeth of the second spline in the axial direction on the end face of the planetary gear.

According to the first to fourth inventions of the present application, the first planetary gear and the second planetary gear can be fixed without press-fitting the second spline into the first spline. As a result, the first planetary gear and the second planetary gear can be fixed while suppressing the deformation of the gear teeth of the first planetary gear.

FIG. 1 is a vertical cross-sectional view of the planetary reducer. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 of the sun gear, the plurality of planetary gears, and the first internal gear. FIG. 3 is a partial vertical sectional view of the planetary gear. FIG. 4 is a plan view of the planetary gear. FIG. 5 is a flowchart showing a manufacturing procedure of planetary gears. FIG. 6 is a vertical cross-sectional view of the first planetary gear and the second planetary gear at the time of manufacturing the planetary gear. FIG. 7 is a view of the vicinity of the fixed portion in the axial direction. FIG. 8 is a plan view of the planetary gear according to the first modification. FIG. 9 is a plan view of the planetary gear according to the second modification.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, the direction parallel to the central axis of the sun gear is the "axial direction", the direction orthogonal to the central axis is the "diameter direction", and the direction along the arc centered on the central axis is the "circumferential direction". Refer to. However, the above-mentioned "parallel direction" also includes a substantially parallel direction. Further, the above-mentioned "orthogonal direction" includes a direction substantially orthogonal to each other.

Further, in the following description, the right side in FIG. 1 is referred to as an “input side”, and the left side in FIG. 1 is referred to as an “output side”.

<1. Planetary reducer according to one embodiment>
FIG. 1 is a vertical cross-sectional view of the planetary reducer 1 according to the embodiment of the present invention. The planetary speed reducer 1 is a device that reduces and outputs the rotational motion of the first rotational speed input from the motor to the rotational motion of the second rotational speed lower than the first rotational speed. The planetary reducer 1 is used, for example, by being incorporated into a joint of a robot together with a motor. However, the planetary reducer 1 may be used for other devices such as an assist suit and an automatic guided vehicle.

As shown in FIG. 1, the planetary reducer 1 of the present embodiment includes one sun gear 10, a plurality of planetary gears 20, a planetary support 30, a first internal gear 40, a second internal gear 50, and an output shaft 60. ing.

The sun gear 10 is a gear arranged along the central axis 91. The sun gear 10 is connected to a motor, which is a drive source, via an input shaft 11. The input shaft 11 is rotatably supported by a casing (not shown) via a bearing. The sun gear 10 and the input shaft 11 rotate around the central shaft 91 at the first rotation speed before deceleration by the driving force input from the motor. A plurality of external teeth 12 are provided on the outer peripheral surface of the sun gear 10. The plurality of external teeth 12 are provided at a constant angular pitch about the central axis 91. Each external tooth 12 projects radially outward on the outer peripheral surface of the sun gear 10.

The planetary gear 20 is a gear arranged on the radial outer side of the sun gear 10. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 of the sun gear 10, the plurality of planetary gears 20, and the first internal gear 40. However, in FIG. 2, in order to avoid complication of the drawing, the hatching showing the cross section and the illustration of the teeth of each gear are omitted. As shown in FIG. 2, in the present embodiment, three planetary gears 20 are arranged at equal intervals around the sun gear 10. However, the number of planetary gears 20 included in the planetary speed reducer 1 may be 1 to 2, or 4 or more.

Each planetary gear 20 has a pin hole 23 in the center. A carrier pin 32, which will be described later, is inserted into the pin hole 23. Each planetary gear 20 is rotatably supported by the carrier pin 32 about a planetary axis 92 parallel to the central axis 91.

As shown in FIG. 1, the planetary gear 20 has a first planetary gear 21 and a second planetary gear 22. The first planetary gear 21 and the second planetary gear 22 are separate members and are fixed to each other. The first planetary gear 21 is an annular gear that meshes with the sun gear 10. The first planetary gear 21 has a plurality of first gear teeth 211 on the outer peripheral surface. The plurality of first gear teeth 211 are provided at a constant angular pitch about the planetary axis 92. Each of the first gear teeth 211 projects outward on the outer peripheral surface of the first planetary gear 21. The first gear tooth 211 meshes with the external tooth 12 of the sun gear 10 described above.

The second planetary gear 22 is a gear having a smaller diameter than the first planetary gear 21. The second planetary gear 22 has a plurality of second gear teeth 221 on the outer peripheral surface. The plurality of second gear teeth 221 are provided at a constant angular pitch about the planetary axis 92. Each second gear tooth 221 projects outward on the outer peripheral surface of the second planetary gear 22. The plurality of second gear teeth 221 are located on the output side of the plurality of first gear teeth 211. Further, the number of the first gear teeth 211 of the first planetary gear 21 and the number of the second gear teeth 221 of the second planetary gear 22 are different.

The planetary support unit 30 is a unit that supports a plurality of planetary gears 20. As shown in FIG. 1, the planetary support portion 30 has a cage-shaped carrier 31 and a plurality of carrier pins 32. The carrier 31 is an annular member centered on the central axis 91. The carrier 31 is rotatably supported around the central axis 91. The carrier 31 has a plurality of window portions 33. The window portion 33 is a hole that penetrates the carrier 31 in the radial direction. The plurality of window portions 33 are provided at equal intervals about the central axis 91. The plurality of carrier pins 32 are fixed to the carrier 31 in a state of being spaced apart in the circumferential direction. Each carrier pin 32 extends axially along the planetary axis 92 at the window 33.

The planetary gear 20 is arranged in the window 33 of the carrier 31. Further, the planetary gear 20 is rotatably supported by the carrier pin 32 via a bearing 34. For the bearing 34, for example, a needle bearing is used. However, instead of the needle bearing, another type of bearing such as a ball bearing may be used. The planetary gear 20 can revolve around the central axis 91 together with the carrier 31 while rotating around the planetary axis 92.

The first internal gear 40 is an annular gear that meshes with the first planetary gear 21 on the radial outer side of the plurality of planetary gears 20. The first internal gear 40 is arranged coaxially with the central axis 91. The first internal gear 40 is fixed to a casing (not shown). Therefore, the first internal gear 40 is kept stationary even when the planetary reducer 1 is driven. The first internal gear 40 has a plurality of first internal teeth 41. The plurality of first internal teeth 41 are provided at a constant angular pitch about the central axis 91. Each of the first internal teeth 41 projects radially inward on the inner peripheral surface of the first internal gear 40. The first gear tooth 211 of the first planetary gear 21 described above meshes with the first internal tooth 41 of the first internal gear 40.

The second internal gear 50 is an annular gear that meshes with the second planetary gear 22 on the radial outer side of the plurality of planetary gears 20. The second internal gear 50 is located on the output side of the first internal gear 40. Further, the second internal gear 50 is arranged coaxially with the central shaft 91. The second internal gear 50 is rotatably supported by a casing (not shown) via a bearing. A bearing 35 is interposed between the carrier 31 and the second internal gear 50. Therefore, the carrier 31 and the second internal gear 50 can rotate at different rotation speeds.

The second internal gear 50 has a plurality of second internal teeth 51. The plurality of second internal teeth 51 are provided at a constant angular pitch about the central axis 91. Each second internal tooth 51 projects radially inward on the inner peripheral surface of the second internal gear 50. The second gear tooth 221 of the second planetary gear 22 described above meshes with the second internal tooth 51 of the second internal gear 50. The number of first internal teeth 41 included in the first internal gear 40 and the number of second internal teeth 51 included in the second internal gear 50 are different.

The output shaft 60 is a shaft arranged along the central axis 91. The output shaft 60 is located on the output side of the carrier 31. In the present embodiment, the second internal gear 50 and the output shaft 60 are formed of a single member. However, the second internal gear 50 and the output shaft 60 may be separate members.

When the sun gear 10 rotates at the first rotation speed, the planet gear 20 rotates about the planet axis 92 due to meshing with the sun gear 10. Further, the planetary gear 20 revolves around the sun gear 10 along the first internal gear 40 by meshing with the first internal gear 40. That is, the plurality of planetary gears 20 revolve around the central axis 91 while rotating around the planetary axis 92. At this time, the revolution rotation speed of the planetary gear 20 centered on the central axis 91 is an intermediate rotation speed lower than the first rotation speed.

Further, as described above, the number of the first internal teeth 41 of the first internal gear 40 and the number of the second internal teeth 51 of the second internal gear 50 are different. Therefore, as the planetary gear 20 revolves, the second internal gear 50 rotates at a rotation speed corresponding to the difference in the number of teeth with respect to the first internal gear 40. The rotation speed of the second internal gear 50 is a second rotation speed that is even lower than the intermediate rotation speed. As a result, the second internal gear 50 and the output shaft 60 rotate at the second rotation speed around the central shaft 91. Therefore, the rotational motion of the second rotation speed after deceleration can be extracted from the output shaft 60.

<2. About planetary gears ＞
Subsequently, a more detailed structure of the planetary gear 20 described above will be described. FIG. 3 is a partial vertical sectional view of the planetary gear 20. FIG. 4 is a plan view of the end face of the planetary gear 20 on the input side as viewed in the axial direction.

As shown in FIGS. 3 and 4, the first planetary gear 21 has a first spline 70 on its inner peripheral surface. The first spline 70 has a plurality of internal teeth 71 projecting inward. The plurality of internal teeth 71 are provided at a constant angular pitch about the planetary axis 92. Each internal tooth 71 extends linearly along the axial direction.

The second planetary gear 22 has a second spline 80 on the outer peripheral surface. That is, the second planetary gear 22 has a gear portion 222 having the plurality of second gear teeth 221 described above, and an insertion portion 223 having the second spline 80. The insertion portion 223 is located on the input side of the gear portion 222. The second spline 80 has a plurality of external teeth 81 projecting outward. The plurality of external teeth 81 are provided at a constant angular pitch about the planetary axis 92. Each external tooth 81 extends linearly along the axial direction. The number of internal teeth 71 of the first spline 70 and the number of external teeth 81 of the second spline 80 are the same.

In the second planetary gear 22, the number of the second gear teeth 221 and the number of the outer teeth 81 are the same. The second gear tooth 221 and the outer tooth 81 are connected in the axial direction. However, the height of the external teeth 81 is lower than the height of the second gear teeth 221. That is, the external tooth 81 of the second spline 80 has a shape in which the second gear tooth 221 is extended to the input side and the tip thereof is cut. With such a structure, it is easy to process the outer teeth 81 together with the second gear teeth 221 at the time of manufacturing the second planetary gear 22. Therefore, the man-hours required for manufacturing the second planetary gear 22 can be reduced.

FIG. 5 is a flowchart showing a manufacturing procedure of the planetary gear 20. As shown in FIG. 5, at the time of manufacturing the planetary gear 20, first, the first planetary gear 21 and the second planetary gear 22 are prepared (step S1). Then, the insertion portion 223 of the second planetary gear 22 is inserted from the output side of the first planetary gear 21 to the inside of the first planetary gear 21. As a result, the insertion portion 223 of the second spline 80 is fitted inside the first spline 70 (step S2).

In step S2, the outer teeth 81 of the second spline 80 are inserted between the adjacent internal teeth 71 of the first spline 70, respectively. Then, the tip of the internal tooth 71 of the first spline 70 and the tooth bottom of the external tooth 81 of the second spline 80 face each other. Further, the tip of the external tooth 81 of the second spline 80 and the tooth bottom of the internal tooth 71 of the first spline 70 face each other.

In step S2, the first spline 70 and the second spline 80 are fitted by a gap fit or an intermediate fit instead of press fitting. That is, the internal teeth 71 of the first spline 70 and the external teeth 81 of the second spline 80 are sized so as not to come into contact with each other in at least a part of the tolerance range. In this way, the distortion of the first planetary gear 21 due to the fitting can be suppressed. Therefore, the change in the tooth profile of the first gear tooth 211 can be suppressed.

FIG. 6 is a vertical cross-sectional view of the first planetary gear 21 and the second planetary gear 22 after the completion of step S2. When the fitting of the second spline 80 to the first spline 70 is completed, as shown in FIG. 6, the axial position of the input side end surface of the first planetary gear 21 and the input side end surface of the second planetary gear 22 The axial position matches.

Next, the boundary between the first spline 70 and the second spline 80 is crimped in the axial direction on the input-side end faces of the first planetary gear 21 and the second planetary gear 22 (step S3). Specifically, as shown in FIG. 6, the crimping pressing pin P is pushed from the input side of the first planetary gear 21 and the second planetary gear 22 toward the boundary between the first spline 70 and the second spline 80. Hit. As a result, the end faces of the first spline 70 and the second spline 80 on the input side are partially plastically deformed. As a result, as shown in FIGS. 3 and 4, the fixing portion 25 is formed at the boundary between the first spline 70 and the second spline 80.

The fixing portion 25 is formed at, for example, one place in the circumferential direction. However, the fixing portions 25 may be formed at a plurality of locations in the circumferential direction.

FIG. 7 is a view of the vicinity of the fixed portion 25 in the axial direction. In FIG. 7, the tooth profile cross section of the second spline 80 before caulking is shown by an alternate long and short dash line. As shown in FIG. 7, the fixing portion 25 of the present embodiment is located at the boundary between the tip of the internal tooth 71 of the first spline 70 and the tooth bottom of the external tooth 81 of the second spline 80.

By caulking in step S3, the tooth profile cross section near the tooth bottom of the second spline 80 is enlarged as shown by the broken line arrow in FIG. As a result, the tooth profile cross section of the second spline 80 in the fixing portion 25 becomes larger than the tooth profile cross section of the portion other than the fixing portion 25 of the second spline 80. Further, the first gap 26 between the tip of the internal tooth 71 of the first spline 70 and the tooth bottom of the external tooth 81 of the second spline 80 is larger than the first gap 26 of the portion other than the fixing portion 25. It becomes smaller.

Further, in the fixing portion 25, the side surface of the internal tooth 71 of the first spline 70 and the side surface of the external tooth 81 of the second spline 80 are in close contact with each other. As a result, the first planetary gear 21 and the second planetary gear 22 are fixed. That is, the axial misalignment of the first planetary gear 21 with respect to the second planetary gear 22 is prevented.

As described above, the planetary gear 20 of the planetary reducer 1 has a fixed portion 25 formed by caulking on the end surface on the input side. Therefore, the first planetary gear 21 and the second planetary gear 22 can be fixed without press-fitting the second spline 80 into the first spline 70. As a result, the first planetary gear 21 and the second planetary gear 22 can be fixed while suppressing the change in the tooth profile of the first gear tooth 211 of the first planetary gear 21.

At the end face of the planetary gear 20 on the input side, the fixed portion 25 is recessed toward the output side more than the other portions. Therefore, the first planetary gear 21 and the second planetary gear 22 are fixed without enlarging the axial dimension of the planetary gear 20. Further, the fixing portion 25 does not come into contact with the first internal gear 40. As a result, sliding friction during driving of the planetary reducer 1 is suppressed.

As shown in FIG. 7, the tooth tips of the internal teeth 71 of the first spline 70 and the tooth tips of the external teeth 81 of the second spline 80 are both flatly chamfered in the axial direction. Further, in the axial direction, both the side surface of the internal tooth 71 of the first spline 70 and the side surface of the external tooth 81 of the second spline 80 are involute curves. If the internal teeth 71 and the external teeth 81 are formed in such a shape, it becomes easy to match the phases of the first planetary gear 21 and the second planetary gear 22. Further, the first gap 26 between the tip of the internal tooth 71 of the first spline 70 and the tooth bottom of the external tooth 81 of the second spline 80 becomes smaller. Therefore, the area of the fixed portion 25 in the axial view can be reduced.

<3. Modification example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Hereinafter, various modifications will be described focusing on the differences from the above-described embodiment.

<3-1. First modification>
FIG. 8 is a plan view of the planetary gear 20 according to the first modification. In this first modification, the fixing portion 25 is located at the boundary between the root of the internal tooth 71 of the first spline 70 and the tip of the external tooth 81 of the second spline 80. In the fixing portion 25, the second gap 27 between the tooth bottom of the internal tooth 71 of the first spline 70 and the tooth tip of the external tooth 81 of the second spline 80 is the second portion other than the fixing portion 25. It is smaller than the gap 27. Even with such a structure, the first planetary gear 21 and the second planetary gear 22 can be fixed by the fixing portion 25 formed by caulking.

However, in the state before the fixing portion 25 is formed, the first gap 26 between the tip of the internal tooth 71 of the first spline 70 and the tooth bottom of the external tooth 81 of the second spline 80 is the first spline. It is smaller than the second gap 27 between the base of the inner tooth 71 of 70 and the tip of the outer tooth 81 of the second spline 80. Therefore, as in the above embodiment, if the fixing portion 25 is provided in the vicinity of the first gap 26, the internal teeth 71 and the external teeth 81 can be brought into close contact with each other more easily.

<3-2. Second modification>
FIG. 9 is a plan view of the planetary gear 20 according to the second modification. In this second modification, only the external teeth 81 of the second spline 80 are crimped in the axial direction, not the boundary between the first spline 70 and the second spline 80. As a result, the fixing portion 25 is formed on the external teeth 81 of the second spline 80. Even in this case, the side surface of the external tooth 81 and the side surface of the internal tooth 71 are in close contact with each other because the tooth profile cross section of the external tooth 81 is larger than the external tooth 81 tooth profile cross section of the portion other than the fixing portion 25. As a result, the first planetary gear 21 and the second planetary gear 22 can be fixed.

<3-3. Other variants>
The detailed shape of the planetary reducer may differ from the shape shown in each figure of the present application. Further, the elements appearing in the above-described embodiments and modifications may be appropriately combined as long as there is no contradiction.

The present invention can be used in planetary gears, planetary reducers, and methods for manufacturing planetary gears.

1 Planetary reducer 10 Sun gear 11 Input shaft 12 External teeth 20 Planetary gear 21 1st planetary gear 22 2nd planetary gear 23 Pin hole 25 Fixed part 26 1st gap 27 2nd gap 30 Planetary support part 31 Carrier 32 Carrier pin 33 Window 34 Bearing 35 Bearing 40 1st internal gear 41 1st internal gear 50 2nd internal gear 51 2nd internal gear 60 Output shaft 70 1st spline 71 Internal tooth 80 2nd spline 81 External tooth 91 Central axis 92 Planetary axis 211 1st Gear tooth 221 Second gear tooth 222 Gear part 223 Insert part P Pressing pin

Claims (10)

Planetary gears used in planetary reducers
The annular first planetary gear and
A second planetary gear fixed to the first planetary gear and having a diameter smaller than that of the first planetary gear.
Have,
The first planetary gear has a first spline having a plurality of internal teeth extending in the axial direction on the inner peripheral surface.
The second planetary gear has a second spline on the outer peripheral surface having a plurality of external teeth extending in the axial direction.
The first spline and the second spline are fitted by a gap fit or an intermediate fit,
It has one or more fixing parts on the end face in the axial direction.
In the fixed portion, the tooth profile cross section of the second spline is larger than the tooth profile cross section of the other portion of the second spline.
A planetary gear in which the internal teeth and the external teeth are in close contact with each other in the fixed portion. Planetary gears used in planetary reducers
The annular first planetary gear and
A second planetary gear fixed to the first planetary gear and having a diameter smaller than that of the first planetary gear.
Have,
The first planetary gear has a first spline having a plurality of internal teeth extending in the axial direction on the inner peripheral surface.
The second planetary gear has a second spline on the outer peripheral surface having a plurality of external teeth extending in the axial direction.
The first spline and the second spline are fitted by a gap fit or an intermediate fit,
It has one or more fixing parts on the end face in the axial direction.
In the fixed portion, the first gap between the tooth tip of the first spline and the tooth bottom of the second spline is smaller than the other first gap, or with the tooth bottom of the first spline. The second gap between the second spline and the tooth tip is smaller than the other second gap.
A planetary gear in which the internal teeth and the external teeth are in close contact with each other in the fixed portion. The planetary gear according to claim 1 or 2.
The fixing portion is a planetary gear located at a boundary between the tooth tip of the first spline and the tooth bottom of the second spline. The planetary gear according to claim 1 or 2.
The fixing portion is a planetary gear located at a boundary between the tooth bottom of the first spline and the tooth tip of the second spline. The planetary gear according to any one of claims 1 to 4.
A planetary gear in which the fixed portion is axially recessed from the other portion of the end face. The planetary gear according to any one of claims 1 to 5.
The first planetary gear has a plurality of first gear teeth on the outer peripheral surface, and has a plurality of first gear teeth.
The second planetary gear has a plurality of second gear teeth on the outer peripheral surface, and has a plurality of second gear teeth.
The number of the first gear teeth and the number of the second gear teeth are different.
A planetary gear in which the number of the second gear teeth and the number of the external teeth of the second spline are the same. The planetary gear according to any one of claims 1 to 6.
A planetary gear in which the shapes of the side surfaces of the internal teeth and the external teeth are involute curves in the axial direction. A planetary speed reducer provided with the planetary gear according to any one of claims 1 to 7.
A sun gear that rotates at the first rotation speed before deceleration around the central axis,
A plurality of planetary gears that mesh with the sun gear on the radial outer side of the sun gear.
An annular first internal gear that meshes with the first planetary gear on the radial outer side of the plurality of planetary gears.
An annular second internal gear that meshes with the second planetary gear on the radial outer side of the plurality of planetary gears.
With
A planetary speed reducer in which the second internal gear rotates at a second rotation speed after deceleration with respect to the first internal gear. The method for manufacturing a planetary gear according to any one of claims 1 to 7.
a) A step of fitting the second spline of the second planetary gear inside the first spline of the first planetary gear.
b) A step of forming the fixed portion by crimping the boundary between the first spline and the second spline in the axial direction on the end face of the planetary gear.
A method for manufacturing planetary gears. The method for manufacturing a planetary gear according to any one of claims 1 to 7.
a) A step of fitting the second spline of the second planetary gear inside the first spline of the first planetary gear.
b) A step of forming the fixed portion by crimping the external teeth of the second spline in the axial direction on the end face of the planetary gear.
A method for manufacturing planetary gears.

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