JP2021195991A - Planetary gear train - Google Patents

Abstract

To provide a technology that can sufficiently lubricate a space between a needle roller and a carrier pin, where a large contact pressure occurs, in a planetary gear train.SOLUTION: A planetary gear train includes: a planetary gear 20; a carrier pin 32 which supports the planetary gear 20; and needle rollers 70. The needle rollers 70 are disposed between the carrier pin 32 and the planetary gear 20. The carrier pin 32 has a grease holding part 80. The grease holding part 80 holds semi-solid grease for lubricating the needle roller 70.SELECTED DRAWING: Figure 3

Description

The present invention relates to a planetary gear device.

Conventionally, a planetary gear device 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. The planetary gear device is a device that rotates and revolves the planetary gear by the rotational motion input to the sun gear, and decelerates the rotational motion by outputting the revolution motion of the planetary gear. A conventional planetary gear device is described in, for example, Japanese Patent Application Laid-Open No. 2017-53461.
Japanese Unexamined Patent Publication No. 2017-53461

In the planetary gear device of JP-A-2017-53461, a needle bearing composed of a plurality of rollers is used for the bearing of the planetary gear. Further, the publication describes that a grease holding groove is provided on the inner peripheral surface of the planetary gear for lubrication of the needle bearing.

The needle roller used for the needle bearing is inscribed in the inner peripheral surface of the planetary gear and circumscribed in the carrier pin supporting the planetary gear. Therefore, the needle roller receives a stronger contact pressure with the carrier pin having an circumscribed relationship than with the planetary gear having an inscribed relationship. However, in the structure of JP-A-2017-53461, grease is supplied to the needle bearing from the planetary gear side. Therefore, it is difficult to sufficiently lubricate between the needle roller and the carrier pin, which generate a strong contact pressure.

An object of the present invention is to provide a technique capable of satisfactorily lubricating between a needle roller and a carrier pin in which a strong contact pressure is generated in a planetary gear device.

The present invention comprises a sun gear that rotates about a central axis, a planetary gear that meshes with the sun gear on the radial outer side of the sun gear, and an annular shape that meshes with the planetary gear on the radial outside of the planetary gear. A planetary gear device including an internal gear, wherein the planetary gear revolves around the central axis while rotating around the planetary axis parallel to the central axis, and the planetary gear device is the planetary gear. A carrier pin extending along an axis and supporting the planetary gear, a plurality of needle rollers interposed between the carrier pin and the planetary gear, and a carrier rotating about the central axis together with the carrier pin. Further provided, the carrier pin has a grease holding portion that holds semi-solid grease for lubricating the needle roller.

According to the present invention, grease can be supplied to the needle roller not from the planetary gear side but from the carrier pin side. Therefore, it is possible to satisfactorily lubricate between the needle roller and the carrier pin where a strong contact pressure is generated.

FIG. 1 is a vertical sectional view of the planetary gear device according to the first embodiment. FIG. 2 is a plan view of the sun gear, the plurality of planetary gears, and the planetary support portion according to the first embodiment as viewed from the input side. FIG. 3 is a partial vertical sectional view of the planetary gear device according to the first embodiment. FIG. 4 is a partial vertical sectional view of the planetary gear device according to the second embodiment. FIG. 5 is a partial vertical sectional view of the planetary gear device according to the modified example.

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 "axial direction", the direction orthogonal to the central axis is "diameter direction", and the direction along the arc centered on the central axis is "circumferential direction", respectively. Refer to. However, the above "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. First Embodiment>
<1-1. Overall configuration of planetary reducer>
FIG. 1 is a vertical sectional view of the planetary gear device 1 according to the first embodiment. The planetary gear device 1 is a device that decelerates and outputs the rotational motion of the first rotation speed input from the motor to the rotational motion of the second rotation speed lower than the first rotation speed. The planetary gear device 1 is used by being incorporated in various industrial devices such as industrial robots and packaging machines. However, the planetary gear device 1 may be used for a robot joint, an assist suit, an automatic guided vehicle, or other device.

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

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 with respect to the casing 50 via bearings (not shown). The input shaft 11 and the sun gear 10 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 plan view of the sun gear 10, the plurality of planetary gears 20, and the planetary support 30 as viewed from the input side. However, in FIG. 2, in order to avoid complication of the figure, the illustration of the teeth of each gear is 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 gear device 1 may be 1 to 2 or 4 or more.

Each planetary gear 20 has a pin hole 22 in the center. A carrier pin 32 and a needle bearing 34, which will be described later, are inserted into the pin hole 22. Each planetary gear 20 is rotatably supported by the carrier pin 32 and the needle bearing 34 about a planetary shaft 92 parallel to the central shaft 91.

The planetary gear 20 has a plurality of external teeth 21 on the outer peripheral surface. The plurality of external teeth 21 are provided at a constant angular pitch about the planetary axis 92. Each external tooth 21 projects outward on the outer peripheral surface of the planetary gear 20. The external teeth 12 of the sun gear 10 and the external teeth 21 of the planetary gear 20 mesh with each other.

The planetary support portion 30 is a unit that supports a plurality of planetary gears 20. The planetary support portion 30 has a carrier 31 and a plurality of carrier pins 32. The carrier 31 is arranged coaxially with the central axis 91. A bearing 37 is interposed between the inner peripheral surface of the casing 50 and the carrier 31. The carrier 31 is rotatably supported by the bearing 37 about the central shaft 91.

The carrier 31 has a plurality of through holes 33. The through hole 33 is a hole that penetrates the carrier 31 in the radial direction. The plurality of through holes 33 are provided at equal intervals about the central axis 91. The plurality of carrier pins 32 are arranged at intervals in the circumferential direction. Each carrier pin 32 extends axially along the planetary axis 92 in the through hole 33. Both ends of the carrier pin 32 in the axial direction are fixed to the carrier 31. For example, press fitting is used as a method for fixing the carrier pin 32 to the carrier 31.

The planetary gear 20 is arranged in the through hole 33 of the carrier 31. Further, the planetary gear 20 is rotatably supported by the carrier pin 32 via the needle bearing 34. Therefore, the planetary gear 20 can rotate about the planetary shaft 92 while being supported by the carrier pin 32 and the needle bearing 34. Further, the planetary gear 20 can revolve around the central shaft 91 together with the carrier 31, the carrier pin 32, and the needle bearing 34.

The internal gear 40 is an annular gear that meshes with the planetary gear 20 on the radial outer side of the plurality of planetary gears 20. The internal gear 40 is arranged coaxially with the central axis 91. The internal gear 40 has a plurality of internal teeth 41. The plurality of internal teeth 41 are provided at a constant angle pitch about the central axis 91. Each internal tooth 41 projects radially inward on the inner peripheral surface of the internal gear 40. The external teeth 21 of the planetary gear 20 described above mesh with the internal teeth 41 of the internal gear 40.

The casing 50 is a casing that internally accommodates the above-mentioned sun gear 10, a plurality of planetary gears 20, and a planetary support portion 30. The casing 50 has a substantially cylindrical outer shape centered on the central axis 91. In the present embodiment, the internal gear 40 and the casing 50 are formed of an integral member. However, the internal gear 40 and the casing 50 may be separate parts. The casing 50 is fixed to the frame of the device to be driven. Therefore, the casing 50 and the internal gear 40 are kept stationary even when the planetary gear device 1 is driven.

The output shaft 60 is a columnar member arranged along the central axis 91. The output shaft 60 rotates about the central shaft 91 together with the carrier 31. In this embodiment, the carrier 31 and the output shaft 60 are formed of an integral member. However, the carrier 31 and the output shaft 60 may be separate parts.

When the sun gear 10 rotates at the first rotation speed, the planetary 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 internal gear 40 by meshing with the 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 becomes the second rotation speed lower than the first rotation speed.

Further, when the planetary gear 20 revolves at the second rotation speed, the plurality of carrier pins 32, the carrier 31, and the output shaft 60 also rotate at the second rotation speed around the central shaft 91. Therefore, the rotational motion of the second rotation speed after deceleration can be taken out from the output shaft 60.

<1-2. About the grease holding structure>
Subsequently, the grease holding structure in the planetary gear 20 described above will be described. FIG. 3 is a partial vertical sectional view of the planetary gear device 1 in the vicinity of the planetary gear 20 (region A in FIG. 1).

As shown in FIG. 3, a needle bearing 34 is interposed between the carrier pin 32 and the planetary gear 20. The needle bearing 34 has a plurality of needle rollers 70. The needle roller 70 is a columnar metal component extending in the axial direction. The plurality of needle rollers 70 are arranged in an annular shape around the planetary axis 91. When driving the planetary gear device 1, it is necessary to sufficiently lubricate these plurality of needle rollers 70. Therefore, in the present embodiment, the grease is held by the grease holding portion 80 provided on the carrier pin 32. Grease is a semi-solid oil.

The grease holding portion 80 is a hole extending from the first opening 811 provided on the outer peripheral surface of the carrier pin 32 toward the inside of the carrier pin 32. Specifically, the grease holding portion 80 has a first hole 81 and a second hole 82. The first hole 81 extends from the first opening 811 toward the planetary axis 92. The second hole 82 extends axially from the first hole 81 to the second opening 821 provided on the axial end face of the carrier pin 32. That is, a substantially L-shaped through hole is formed in the first hole 81 and the second hole 82. The grease is held inside the first hole 81 and the second hole 82.

When the planetary gear device 1 is driven, the grease held by the grease holding portion 80 is supplied to the plurality of needle rollers 70 via the first opening 811. The grease is moved from the grease holding portion 80 to the needle roller 70 by the centrifugal force caused by the revolution of the carrier pin 32 around the central axis 91 or the negative pressure generated in the vicinity of the needle roller 70 due to the rolling motion of the needle roller 70. Will be supplied. Further, the grease supplied to the needle roller 70 spreads in the circumferential direction and the axial direction with the rolling motion of the plurality of needle rollers 70. As a result, the plurality of needle rollers 70 are lubricated. As a result, the rotation of the planetary gear 20 around the carrier pin 32 is smoothly performed.

In this planetary gear device 1, semi-solid grease is used instead of liquid oil. By doing so, the grease can be held without flowing out from the grease holding portion 80. Therefore, since it is not necessary to provide an oil seal, the number of parts of the planetary gear device 1 can be reduced. Specifically, in the JIS K 2220 test method, it is preferable to use grease having a consistency of 340 or less.

The needle roller 70 is inscribed in the planetary gear 20. That is, the outer peripheral surface of the needle roller 70 comes into contact with the inner peripheral surface of the planetary gear 20. Further, the needle roller 70 is circumscribed with respect to the carrier pin 32. That is, the outer peripheral surface of the needle roller 70 comes into contact with the outer peripheral surface of the carrier pin 32. A stronger contact pressure is generated at the circumscribed point than at the inscribed point. Therefore, when the planetary gear device 1 is driven, a stronger contact pressure is generated between the needle roller 70 and the carrier pin 32 than between the needle roller 70 and the planetary gear 20.

Therefore, in this planetary gear device 1, grease is supplied to the needle roller 70 from the grease holding portion 80 provided on the carrier pin 32 instead of the planetary gear 20. By doing so, it is possible to better lubricate between the needle roller 70 and the carrier pin 32, which generate a strong contact pressure.

Further, in the structure of the present embodiment, no holes or grooves are formed in the outer peripheral surface of the carrier pin 32 other than the first opening 811. Therefore, a large area of the outer peripheral surface of the carrier pin 32 that can be in contact with the needle roller 70 can be secured. Therefore, it is possible to prevent the carrier pin 32 from reducing the bearing capacity of the needle roller 70.

When the planetary gear device 1 is driven, particularly strong support is provided between the outer peripheral surfaces of the carrier pin 32, both end surfaces in the circumferential direction with respect to the central axis 91 (the portion indicated by reference numeral 321 in FIG. 2) and the needle roller 70. Force is generated. That is, these both end surfaces 321 are particularly important support surfaces for supporting the plurality of needle rollers 70. Therefore, it is preferable that the first opening 811 is provided at a position on the outer peripheral surface of the carrier pin 32 so as to avoid the both end surfaces 321. By doing so, it is possible to suppress a decrease in the bearing capacity of the carrier pin 32 on both end faces 321.

In the present embodiment, the first opening 811 is provided on the end face on the outer peripheral surface of the carrier pin 32 in the radial direction with respect to the central axis 91. In this way, when the planetary gear device 1 is driven, grease can be supplied from the first opening 811 to the needle roller 70 by the centrifugal force generated by the revolution of the carrier pin 32 about the central shaft 91. Therefore, the supply of grease from the grease holding portion 80 to the needle roller 70 can be further promoted.

As shown in FIG. 3, the plurality of needle rollers 70 of the present embodiment includes a plurality of first needle rollers 71 and a plurality of second needle rollers 72. The plurality of first needle rollers 71 are arranged in an annular shape about the planetary axis 92. The plurality of second needle rollers 72 are also arranged in an annular shape around the planetary axis 92. Further, the plurality of first needle rollers 71 and the plurality of second needle rollers 72 are adjacent to each other in the axial direction. By arranging the needle rollers 70 in two rows in this way, the amount of inclination of each needle roller 70 in the axial direction can be suppressed. Therefore, poor lubrication due to the inclination of the needle roller 70 can be suppressed.

Further, in the structure of the present embodiment, the first opening 811 opens toward the boundary between the first needle roller 71 and the second needle roller 72. That is, the first opening 811 is provided on the outer peripheral surface of the carrier pin 32 where the first needle roller 71 and the second needle roller 72 do not originally come into contact with each other. By doing so, the first opening 811 is provided on the outer peripheral surface of the carrier pin 32, and the contact area between the first needle roller 71 and the second needle roller 72 and the carrier pin 32 is minimized. Can be suppressed to.

Further, the grease holding portion 80 of the present embodiment has not only the first hole 81 but also the second hole 82. Therefore, more grease can be held in the grease holding portion 80 as compared with the case where the grease holding portion 80 is composed of only the first hole 81.

As shown in FIG. 3, the second hole 82 is inclined with respect to the planetary axis 92. The radial position of the second hole 82 gradually approaches the outer side in the radial direction as it approaches the first hole 81. In this way, the grease held in the second hole 82 moves to the first hole 81 side due to the centrifugal force accompanying the revolution of the carrier pin 32 with respect to the central axis 91. Therefore, when the planetary gear device 1 is driven, grease can be better supplied from the second hole 82 to the plurality of needle rollers 70 via the first hole 81.

The centrifugal force applied to the grease held in the first hole 81 and the second hole 82 changes according to the driving speed of the planetary gear device 1. Therefore, the amount of grease supplied from the grease holding portion 80 to the needle roller 70 can be adjusted according to the driving speed of the planetary gear device 1. Specifically, it is possible to reduce the amount of grease supplied during low-speed driving and increase the amount of grease supplied during high-speed driving. That is, as the need for lubricating the needle roller 70 increases, the supply of grease can be further promoted.

Further, in the structure of the present embodiment, the second hole 82 of the grease holding portion 80 extends to the second opening 821 provided on the end surface of the carrier pin 32 on the input side (one side in the axial direction). Therefore, grease can be replenished from the second opening 821 to the second hole 82. In particular, as shown in FIGS. 1 to 3, the second hole 82 is exposed on the end surface of the carrier 31 on the input side. Therefore, grease can be replenished from the second opening 821 to the second hole 82 without disassembling the carrier 31, the carrier pin 32, the needle bearing 34, and the planetary gear 20. As a result, the burden on the user for the grease replenishment work can be reduced.

Further, in the structure of the present embodiment, the end surface of the carrier pin 32 on the output side (the other side in the axial direction) faces the bearing 37 in the axial direction. The second opening 821 is provided not on such an end face on the output side of the carrier pin 32 but on the end face on the input side. Therefore, grease can be replenished from the second opening 821 to the second hole 82 without disassembling the carrier 31 and the bearing 37.

<2. 2nd Embodiment>
Subsequently, the second embodiment of the present invention will be described. In the following, the differences from the first embodiment will be mainly described, and duplicate description will be omitted for the parts equivalent to the first embodiment. FIG. 4 is a partial vertical sectional view of the planetary gear device 1 according to the second embodiment.

The structure of the grease holding portion 80 of the planetary gear device 1 of the present embodiment is different from that of the first embodiment. As shown in FIG. 4, the grease holding portion 80 of the present embodiment is a groove provided on the outer peripheral surface of the carrier pin 32.

The grease holding portion 80 of the present embodiment has a first groove 83 and a second groove 84. The first groove 83 is a spiral groove provided on the outer peripheral surface of the carrier pin 32. The second groove 84 is an annular groove provided on the outer peripheral surface of the carrier pin 32. The second groove 84 is provided at a position facing the boundary between the first needle roller 71 and the second needle roller 72. The first groove 83 extends spirally from the second groove 84 toward both sides in the axial direction.

When forming the grease holding portion 80 on the outer peripheral surface of the carrier pin 32, first, an annular second groove 84 is formed on the outer peripheral surface of the carrier pin 32 by cutting. After that, the spiral first groove 83 is formed by cutting from the second groove 84 as a starting point toward both sides in the axial direction. Thereby, the spiral first groove 83 can be easily formed. Further, by making the first groove 83 spiral, it is possible to provide the groove in a wide range of the outer peripheral surface of the carrier pin 32 while suppressing the number of grooves to be machined.

The grease is held inside the first groove 83 and the second groove 84. Therefore, when the planetary gear device 1 is driven, grease is supplied from the first groove 83 and the second groove 84 to the needle roller 70. If the structure of the present embodiment is adopted, grease can be supplied to the needle roller 70 from a wider range of the outer peripheral surface of the carrier pin 32 than in the first embodiment. However, in the present embodiment, since the first groove 83 and the second groove 84 are provided on the outer peripheral surface of the carrier pin 32, the contact area between the carrier pin 32 and the needle roller 70 becomes smaller. Therefore, from the viewpoint of ensuring the bearing capacity between the carrier pin 32 and the needle roller 70, the structure of the first embodiment is preferable.

Also in this embodiment, the annular second groove 84 faces the boundary between the first needle roller 71 and the second needle roller 72. That is, the second groove 84 is provided on the outer peripheral surface of the carrier pin 32 where the first needle roller 71 and the second needle roller 72 do not originally come into contact with each other. By doing so, it is possible to provide the second groove 84 and minimize the decrease in the contact area between the first needle roller 71 and the second needle roller 72 and the carrier pin 32.

Further, as shown in FIG. 4, the planetary gear device 1 has a pair of washers 35 for each planetary gear 20. One of the pair of washers 35 is interposed between the input-side end (one end in the axial direction) of the first needle roller 71 and the carrier 31. The other of the pair of washers 35 is interposed between the output side end (the other end in the axial direction) of the second needle roller 72 and the carrier 31. Each washer 35 has an annular outer shape centered on the planetary axis 92. The hardness of the washer 35 is higher than the hardness of the carrier 31.

By providing such a washer 35, it is possible to prevent the planetary gear 20 and the carrier 31 from directly sliding. Further, it is possible to prevent the carrier 31 from being worn by the pressing force from the needle roller 70.

As shown in FIG. 4, in the present embodiment, the spiral first groove 83 extends from the same axial position as one washer 35 to the same axial position as the other washer 35. Therefore, grease is supplied not only to the needle roller 70 but also to the pair of washers 35. Thereby, the slidability of the planetary gear 20, the washer 35, and the carrier 31 can be further improved.

<3. Modification example>
Although the first embodiment and the second embodiment of the present invention have been described above, the present invention is not limited to the above-described embodiment.

FIG. 5 is a partial vertical sectional view of the planetary gear device according to the modified example of the first embodiment. In the example of FIG. 5, the grease holding portion 80 of the carrier pin 32 has a first hole 81 and a pair of second holes 82. One of the pair of second holes 82 extends from the end of the first hole 81 toward the input side (one side in the axial direction), as in the first embodiment described above. The other end of the pair of second holes 82 extends from the end of the first hole 81 toward the output side (the other side in the axial direction). By expanding the range of the second hole 82 in this way, more grease can be held in the grease holding portion 80.

In any of the first embodiment, the second embodiment, and the modification of FIG. 5, the grease holding portion 80 is at least from the center of the planetary gear 20 in the axial direction to the input side of the planetary gear 20 ( It is provided in the range up to the end (on one side in the axial direction). In this way, by securing the range in the axial direction of the grease holding portion 80, a large amount of grease can be held in the grease holding portion 80.

However, the grease holding portion of the present invention does not necessarily have to be provided over such a range. For example, in the structure of the first embodiment, the second hole 82 may be omitted, and the grease holding portion 80 may be configured only by the first hole 81.

Further, the shape of the details of the planetary gear device may be different from the shape shown in each figure of the present application. Further, each element appearing in the above-described embodiment or modification may be appropriately selected as long as there is no contradiction.

The present invention can be used for planetary gear devices.

1 Planetary gear device 10 Sun gear 11 Input shaft 12 External tooth 20 Planetary gear 21 External tooth 22 Pin hole 30 Planetary support 31 Carrier 32 Carrier pin 33 Through hole 34 Needle bearing 35 Washer 37 Bearing 40 Internal gear 41 Internal tooth 50 Casing 60 Output Shaft 70 Needle roller 71 1st needle roller 72 2nd needle roller 80 Gris holding part 81 1st hole 82 2nd hole 83 1st groove 84 2nd groove 91 Central axis 92 Planetary axis 811 1st opening 821 2nd opening

Claims (15)

A sun gear that rotates around the central axis,
A planetary gear that meshes with the sun gear on the radial outer side of the sun gear,
An annular internal gear that meshes with the planetary gear on the radial outer side of the planetary gear.
It is a planetary gear device equipped with
The planetary gear revolves around the central axis while rotating around the planetary axis parallel to the central axis.
The planetary gear device is
A carrier pin that extends along the planetary axis and supports the planetary gear,
A plurality of needle rollers interposed between the carrier pin and the planetary gear,
A carrier that rotates around the central axis together with the carrier pin,
Further prepare
The carrier pin is
A planetary gear device having a grease holding portion for holding semi-solid grease for lubricating the needle roller. The planetary gear device according to claim 1.
A planetary gear device having a grease consistency of 340 or less according to the JIS K 2220 test method. The planetary gear device according to claim 1 or 2.
The planetary gear device is provided with the grease holding portion at least in a range from the center of the planetary gear in the axial direction to one end of the planetary gear in the axial direction. The planetary gear device according to any one of claims 1 to 3.
The grease holding portion is a planetary gear device which is a hole extending from a first opening provided on the outer peripheral surface of the carrier pin toward the inside of the carrier pin. The planetary gear device according to claim 4.
The first opening is a planetary gear device located on the outer peripheral surface of the carrier pin other than both end faces in the circumferential direction with respect to the central axis. The planetary gear device according to claim 5.
The first opening is a planetary gear device located on an end surface of the outer peripheral surface of the carrier pin that is radially outer with respect to the central axis. The planetary gear device according to any one of claims 4 to 6.
The plurality of needle rollers
A plurality of first needle rollers arranged in an annular shape around the planetary axis, and
A plurality of second needle rollers adjacent to the plurality of first needle rollers in the axial direction and arranged in an annular shape around the planetary axis, and a plurality of second needle rollers.
Have,
The first opening is a planetary gear device that opens toward the boundary between the first needle roller and the second needle roller. The planetary gear device according to any one of claims 4 to 7.
The grease holding portion is
A first hole extending from the first opening toward the planetary axis,
A second hole extending axially from the first hole and
Has a planetary gear device. The planetary gear device according to claim 8.
The second hole is a hole inclined with respect to the planetary axis.
A planetary gear device in which the radial position of the second hole gradually approaches the outside in the radial direction as the first hole is approached. The planetary gear device according to claim 8 or 9.
The second hole is a planetary gear device extending to a second opening provided on the axial end face of the carrier pin. The planetary gear device according to claim 10.
Further having a bearing that rotatably supports the carrier
The second opening is provided on the end face on one side in the axial direction of the carrier pin.
The bearing is a planetary gear device that is axially opposed to the end face on the other side of the carrier pin in the axial direction. The planetary gear device according to any one of claims 1 to 3.
The grease holding portion is a planetary gear device which is a groove provided on the outer peripheral surface of the carrier pin. The planetary gear device according to claim 12.
The grease holding portion is
A planetary gear device including a spiral first groove provided on the outer peripheral surface of the carrier pin. The planetary gear device according to claim 13.
The plurality of needle rollers
A plurality of first needle rollers arranged in an annular shape around the planetary axis, and
A plurality of second needle rollers adjacent to the plurality of first needle rollers in the axial direction and arranged in an annular shape around the planetary axis, and a plurality of second needle rollers.
Have,
The grease holding portion is
Further including an annular second groove facing the boundary between the first needle roller and the second needle roller.
A planetary gear device in which the first groove extends from the second groove to both sides in the axial direction. The planetary gear device according to claim 13 or 14.
Further comprising a pair of annular washers interposed between one end of the needle roller in the axial direction and the carrier, and between the other end of the needle roller in the axial direction and the carrier.
The first groove is a planetary gear device extending from a position in the same axial direction as one of the washers to a position in the same axial direction as the other washer.

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