Planetary gear device and method for manufacturing a planetary gear device

Abstract

The present invention provides a planetary gear device with a novel structure that can reduce the resistance of oil agitation, and a method for manufacturing the planetary gear device. [Solution] The planetary gear device 10 comprises a sun gear 11, a shaft member 12 rotatable integrally with the sun gear 11, a pinion gear 15, a pinion shaft 14 that rotatably supports the pinion gear 15, and a carrier 13. The carrier 13 has a pair of wall portions 24 that are spaced apart and facing each other in the axial direction of the shaft member 12, and a connecting portion 25 that extends in the axial direction and connects the wall portions 24 together. Both ends of the pinion shaft 14 in the axial direction are supported by the wall portions 24. The connecting portion 25 is positioned inward of the pinion shaft 14 in the radial direction of the shaft member 12.

Description

Technical Field

[0005] , ,

[0001] The present disclosure relates to a planetary gear device and a method for manufacturing a planetary gear device.

Background Art

[0002] The planetary gear device described in Patent Document 1 includes a sun gear, pinion gears, and a carrier. The sun gear is provided on a first input / output member as a shaft member. The pinion gears mesh with the sun gear and are rotatably supported on pinion shafts fixed to the carrier. The pinion gears also mesh with a ring gear. The carrier has a carrier case and a carrier cover that face each other in the axial direction. The carrier case has a plurality of bridge portions that extend axially from an end portion on the radially outer side. The axial end portions of each bridge portion are joined to the outer peripheral side of the carrier cover by welding or the like. That is, the carrier case and the carrier cover are connected by a plurality of bridge portions at the end portions on the radially outer side.

[0003] The oil (lubricating oil) supplied to the planetary gear device moves from the main oil passage into the carrier internal oil passage provided in the carrier by centrifugal force, enters the pinion shaft internal oil passage provided in the pinion shaft via a retention space from the carrier internal oil passage, and is further provided to the pinion gears and the like from the pinion shaft internal oil passage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above configuration, the rotation of the pinion gear and ring gear agitates the supplied oil, lubricating the planetary gear system. However, in this case, the presence of a bridge between adjacent pinion gears in the circumferential direction increases agitation resistance (agitation loss), raising concerns about decreased fuel efficiency.

[0006] Therefore, the present disclosure aims to provide a planetary gear device with a novel structure that can reduce the oil stirring resistance, and a method for manufacturing a planetary gear device. [Means for solving the problem]

[0007] The planetary gear device of the present disclosure comprises a sun gear, a shaft member rotatable integrally with the sun gear, a pinion gear that meshes with the sun gear, a pinion shaft that rotatably supports the pinion gear, and a carrier, wherein the carrier has a pair of wall portions that are spaced apart and face each other in the axial direction of the shaft member, and a connecting portion that extends in the axial direction and connects the wall portions, the axial ends of the pinion shaft are each supported by the wall portions, and the connecting portion is positioned inward from the pinion shaft in the radial direction of the shaft member. [Effects of the Invention]

[0008] This disclosure makes it possible to provide a planetary gear device with a novel structure that can reduce the oil stirring resistance. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of the planetary gear device of Embodiment 1. [Figure 2] Figure 2 is an enlarged cross-sectional view of the main part of the planetary gear device of Embodiment 1. [Figure 3] Figure 3 is a cross-sectional view of the planetary gear device of Embodiment 1, taken along line AA in Figure 2. [Figure 4]Figure 4 is a cross-sectional view of the planetary gear device of Embodiment 1, taken along line BB in Figure 2. [Figure 5] Figure 5 is a partially broken perspective view of the carrier in the planetary gear device of Embodiment 1. [Figure 6] Figure 6 is a schematic diagram showing the manufacturing method of the planetary gear device according to Embodiment 1, in which the material is set in a mold and a tool is positioned on the radially outer side of the material. [Figure 7] Figure 7 is a schematic diagram showing the manufacturing method of the planetary gear device according to Embodiment 1, and shows the state after the tool is pressed against the material from the state shown in Figure 6, causing the material to split open. [Modes for carrying out the invention]

[0010] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described. The planetary gear device of this disclosure is (1) The device comprises a sun gear, a shaft member rotatable integrally with the sun gear, a pinion gear that meshes with the sun gear, a pinion shaft that rotatably supports the pinion gear, and a carrier, wherein the carrier has a pair of wall portions that are spaced apart and face each other in the axial direction of the shaft member, and a connecting portion that extends in the axial direction and connects the wall portions, the axial ends of the pinion shaft are each supported by the wall portions, and the connecting portion is positioned inward from the pinion shaft in the radial direction of the shaft member. Since the connecting portion is positioned inward from the pinion shaft in the radial direction of the shaft member, the oil supplied to the planetary gear device can avoid contact with the connecting portion at the radial position where the pinion shaft is located, thereby reducing the resistance to oil agitation.

[0011] (2) In the planetary gear device described in (1) above, it is preferable that the pair of wall portions and the connecting portion are integrated without welding, and the carrier has a split groove between the pair of wall portions that is concave toward the connecting portion. According to the configuration of (2) above, a pair of wall portions and a connecting portion can be easily manufactured while forming a splitting groove by splitting processing. In particular, since the pair of wall portions and the connecting portion are integrally formed without welding, the number of parts is not increased, and the cost can be reduced.

[0012] (3) In the planetary gear device according to (2) above, the pinion gear has a large pinion gear that meshes with the sun gear, and a small pinion gear that has a smaller diameter than the large pinion gear and is coaxially connected to the large pinion gear. The connecting portion preferably has a cylindrical portion disposed inside the small pinion gear, and a plurality of pieces facing each other in the circumferential direction of the shaft member across an access hole that allows meshing between the sun gear and the large pinion gear. According to the configuration of (3) above, even if the connecting portion is present on the side where the sun gear is located, the sun gear and the pinion gear can be meshed with each other through the access hole. As a result, simplification, miniaturization, and weight reduction (reduction of inertial mass) of the configuration of the planetary gear device can be achieved.

[0013] Moreover, the manufacturing method of the planetary gear device of the present disclosure is (4) A manufacturing method of the planetary gear device according to (2) or (3) above, including a step of pressing a tool against the cylindrical or disk-shaped material from the outside in the radial direction to split the material and form the splitting groove. According to the configuration of (4) above, by forming the splitting groove by splitting processing, a pair of wall portions and a connecting portion can be easily manufactured. As a result, the number of parts and the cost can be reduced.

[0014] [Details of Embodiments of the Present Disclosure] Specific examples of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0015] <Embodiment 1> The planetary gear device 10 of Embodiment 1 of the present disclosure is provided, for example, in a transaxle of an electric vehicle such as a HEV (Hybrid Electric Vehicle) or a PHEV (Plug-in Hybrid Electric Vehicle). The planetary gear device 10 is housed in a casing (not shown) and rotates around a rotation axis R disposed substantially horizontally. As shown in FIGS. 1 and 2, the planetary gear device 10 includes a sun gear 11, a shaft member 12, a carrier 13, a plurality of pinion shafts 14, and a plurality of pinion gears 15. In the planetary gear device 10, the pinion gear 15 can revolve around the sun gear 11 while rotating, and is drivingly connected to an internal combustion engine or the like via any one of the shaft member 12, a ring gear (not shown), and other shaft members (not shown). In the following description, unless otherwise specified, the direction along the rotation axis R (parallel direction) is defined as the axial direction, the direction around the rotation axis R is defined as the circumferential direction, and the direction orthogonal to the rotation axis R is defined as the radial direction. Also, unless otherwise specified, simply referring to an end means an end in the axial direction.

[0016] The shaft member 12 is supported by a bearing portion (not shown) and rotates around the rotation axis R. The central axis of the shaft member 12 coincides with the rotation axis R. The carrier 13 rotates around the rotation axis R. The plurality of pinion shafts 14 are supported by the carrier 13. The plurality of pinion gears 15 are rotatably supported on respective ones of the plurality of pinion shafts 14.

[0017] The shaft member 12 is manufactured by, for example, forging and then performing machining. The shaft member 12 has a long cylindrical shape in the axial direction. As shown in FIG. 2, a main oil passage 16 is provided along the axial direction in the central portion of the shaft member 12. A branch oil passage 17 branched from the main oil passage 16 and extending radially outward is provided in the shaft member 12. The radially outer end of the branch oil passage 17 opens to the outer peripheral surface of the shaft member 12.

[0018] The sun gear 11 is integrally mounted with the shaft member 12 on the outer circumferential surface of one end of the shaft member 12. The external teeth of the sun gear 11 are arranged in a circumferential direction on the outer circumferential surface of the shaft member 12. As shown in Figure 3, the sun gear 11 meshes with the large pinion gear 15A of the pinion gear 15, which will be described later, at multiple positions spaced apart in the circumferential direction.

[0019] Multiple pinion gears 15 are arranged at intervals around the axis of the shaft member 12. In this embodiment 1, each pinion gear 15 is arranged at equal intervals of 90 degrees around the rotation axis R. As shown in Figure 1, each pinion gear 15 has a large pinion gear 15A and a small pinion gear 15B. For example, the large pinion gear 15A and the small pinion gear 15B are helical gears. The large pinion gear 15A meshes with the sun gear 11 on its inner circumference. The small pinion gear 15B meshes with a ring gear (not shown) on its outer circumference. The ring gear (not shown) is rotatably arranged around the rotation axis R relative to the shaft member 12.

[0020] The large pinion gear 15A and the small pinion gear 15B are arranged side by side in the axial direction. As shown in Figure 2, the pinion gear 15 has a cylindrical sleeve 18 that extends from the small pinion gear 15B to the other end in the axial direction. The large pinion gear 15A is press-fitted and fixed to the outer surface of the sleeve 18.

[0021] Multiple pinion shafts 14 are arranged at 90-degree intervals around the axis of the shaft member 12 so as to correspond to each pinion gear 15. The central axis of each pinion shaft 14 is set parallel to the central axis of the shaft member 12. Each pinion shaft 14 has an internal oil passage 21 extending in the axial direction and a discharge oil passage 22 that branches off from the internal oil passage 21 and extends radially outward. One end of the internal oil passage 21 is closed at one end of the pinion shaft 14. The other end of the internal oil passage 21 opens to the other end face of the pinion shaft 14. The radial outer end of the discharge oil passage 22 opens to the outer circumferential surface of the pinion shaft 14. For example, two discharge oil passages 22 are provided side by side on the pinion shaft 14, spaced apart, so as to correspond to the large pinion gear 15A and the small pinion gear 15B, respectively.

[0022] Needle bearings 23 are provided between the outer circumferential surface of the pinion shaft 14 and the inner circumferential surface of the pinion gear 15. The pinion gear 15 is rotatably supported on the pinion shaft 14 via the needle bearings 23. For example, the needle bearings 23 are positioned at both ends of the pinion gear 15, corresponding to two oil discharge passages 22.

[0023] As shown in Figure 5, the carrier 13 has a pair of opposing wall sections 24 spaced apart in the axial direction, and a connecting section 25 that extends axially between each wall section 24 and connects them. The pair of wall sections 24 and the connecting section 25 are integrally connected without welding by a splitting process described later. The pair of wall sections 24 and the connecting section 25 exhibit an H-shape in a side view seen from the radial outside by dividing the splitting groove 26 described later.

[0024] In this first embodiment, each wall portion 24 is disc-shaped and arranged to expand radially with its wall surface (plate surface) facing axially. Each pinion gear 15 is positioned between each wall portion 24 in the axial direction. Each pinion shaft 14 is supported and fixed to each wall portion 24.

[0025] As shown in Figure 2, of the wall portions 24, the first wall portion 24A adjacent to the small pinion gear 15B is located at the end of the planetary gear device 10. Of the wall portions 24, the second wall portion 24B adjacent to the large pinion gear 15A is located axially towards the center from the end of the planetary gear device 10. The diameters of the first wall portion 24A and the second wall portion 24B are the same. The axial thickness of the second wall portion 24B is greater than the axial thickness of the first wall portion 24A.

[0026] A first axial hole 27A with a circular cross-section is provided in the center of the first wall portion 24A, penetrating axially (in the thickness direction of the first wall portion 24A). Other shaft members (not shown) can be inserted into the first axial hole 27A. Similarly, a second axial hole 27B with a circular cross-section is provided in the center of the second wall portion 24B, penetrating axially (in the thickness direction of the second wall portion 24B). The end of the shaft member 12 is rotatably inserted into the second axial hole 27B.

[0027] As shown in Figure 5, the first wall portion 24A and the second wall portion 24B are provided with a first insertion hole 28A and a second insertion hole 28B, respectively, which have a circular cross-section. The first insertion hole 28A and the second insertion hole 28B are arranged coaxially with each pinion shaft 14 at 90-degree intervals in the circumferential direction. The first insertion hole 28A penetrates the first wall portion 24A in the axial direction. The second insertion hole 28B extends axially through the second wall portion 24B, with one end closer to the first wall portion 24A opening at one end face of the second wall portion 24B, and the other end further away from the first wall portion 24A being closed at the other end of the second wall portion 24B. One end of the pinion shaft 14 is inserted into the first insertion hole 28A and crimped and fixed to the periphery of the first insertion hole 28A. The other end of the pinion shaft 14 is press-fitted and fixed to the second insertion hole 28B. As shown in Figure 2, thrust washers 29 are provided between one end face of the pinion gear 15 and the first wall portion 24A, and between the other end face of the pinion gear 15 and the second wall portion 24B. The thrust washers 29 have the function of reducing frictional resistance between the pinion gear 15 and the wall portion 24, as well as suppressing axial movement of the needle bearing 23.

[0028] As shown in Figures 2 and 5, the second wall portion 24B has a plurality of carrier internal oil passages 31. Each carrier internal oil passage 31 is arranged at 90-degree intervals in the circumferential direction, corresponding to each second insertion hole 28B. Each carrier internal oil passage 31 extends radially, its radial inner end intersecting and communicating with the main oil passage 16, and intersecting and communicating with each second insertion hole 28B midway along the radial direction. As shown in Figure 2, the radial outer end of the carrier internal oil passage 31 is closed by a plug 32 on the radial outer end side of the second wall portion 24B.

[0029] As shown in Figure 5, the connecting portion 25 extends in the axial direction, with one end in the axial direction integrally connected to the center of the first wall portion 24A, and the other end in the axial direction integrally connected to the center of the second wall portion 24B. In other words, the connecting portion 25 connects the centers of the first wall portion 24A and the second wall portion 24B. The connection portions between the first wall portion 24A and the second wall portion 24B and the connecting portion 25 are seamlessly integrated without welding by a splitting process described later.

[0030] The connecting portion 25 has a cylindrical portion 33 and a plurality of side portions 34. The cylindrical portion 33 and the plurality of side portions 34 are arranged in the axial direction. The cylindrical portion 33 is located at one end of the connecting portion 25 in the axial direction (the first wall portion 24A side). Each side portion 34 is located at the other end of the connecting portion 25 in the axial direction (the second wall portion 24B side).

[0031] The cylindrical portion 33 is cylindrical in shape and its axis is oriented in the front-rear direction. Each piece portion 34 is piece-shaped and is spaced apart in the circumferential direction parallel to the outer circumference of the shaft member 12. At the center of the carrier 13, the cylindrical portion 33 protrudes from the first wall portion 24A toward the other end in the axial direction (towards the shaft member 12), and each piece portion 34 protrudes from the other end of the cylindrical portion 33 toward the other end, with the other end of each piece portion 34 integrally connected to the second wall portion 24B. One end of the cylindrical portion 33 is integrally connected to the opening edge of the first shaft hole 27A of the first wall portion 24A. The other end of each piece portion 34 is integrally connected to the opening edge of the second shaft hole 27B of the second wall portion 24B.

[0032] As shown in Figure 3, each piece 34 is non-contacting and adjacent to the large pinion gear 15A in the circumferential direction, and there are a total of four pieces, corresponding to each pinion gear 15. Both circumferential sides (surfaces facing the circumferential direction) of each piece 34 are curved in an arc along the outer circumferential surface of the large pinion gear 15A. The inner circumferential surface of each piece 34 is also curved in an arc along the outer circumferential surface of the sun gear 11. Between each pair of circumferentially adjacent pieces 34, four access holes 35 are formed, allowing each large pinion gear 15A to access the sun gear 11. The large pinion gear 15A is allowed to mesh with the sun gear 11 through the access holes 35.

[0033] As shown in Figure 5, the cylindrical portion 33 has a plurality of internal oil passages 36. Each internal oil passage 36 is arranged at 90-degree intervals in the circumferential direction of the cylindrical portion 33. The radial inner end of each internal oil passage 36 intersects with a main oil passage of another shaft member, etc., which is not shown. As shown in Figure 2, the radial outer end of each internal oil passage 36 is located radially inward from the second insertion hole 28B and faces a thrust washer 29 positioned between one end face of each pinion gear 15 and the first wall portion 24A. Also, as shown in Figure 5, the cylindrical portion 33 has a plurality of connecting oil passages 37 that extend from the middle of the radial direction of each internal oil passage 36 to the other end in the axial direction, with the other end leading to each access hole 35.

[0034] Next, an example of a manufacturing method for the carrier 13 will be described. In this embodiment 1, the carrier 13 is manufactured by a cracking process in which the material 113 is split open. As shown in Figure 6, the material 113 is held in a mold 200 corresponding to the shape of the carrier 13. The mold 200 has an H-shape in side view and has a column 225 extending in the axial direction and a pair of flanges 224 protruding radially outward from both ends of the column 225. The material 113 is, for example, cylindrical and is fitted around the outer circumference of the column 225, and its axial displacement is prevented by each flange 224.

[0035] The mold 200 holding the material 113 is rotated around the axis of the column 225. A first tool 310 (roller) is positioned at a location corresponding to the axial middle portion of the outer surface of the material 113 and rotated synchronously. In this state, the first tool 310 is moved toward the center of the column 225 and pressed against the outer surface of the axial middle portion of the material 113. The part of the first tool 310 that contacts the material 113 has a rounded tip shape. The axial middle portion of the material 113 is pressed open by the first tool 310.

[0036] Next, as shown in Figure 7, the second tool 320 (roller) is pressed against the outer surface of the material 113 while moving in the axial and radial directions. The portion of the second tool 320 that contacts the material 113 has a wedge-shaped tip. The axial middle portion of the material 113 is rolled vertically along the column portion 225 by the second tool 320, reducing its thickness, and both ends of the material 113 are rolled horizontally along the flange portions 224. As a result, the material 113 is given an axial extension portion 125 corresponding to the connecting portion 25, and a pair of radially extended portions 124 corresponding to the pair of wall portions 24. Between the pair of extended portions 124 (wall portions 24) and on the radially outer side of the connecting portion 25 (extension portion 125), a circumferential crack groove 26, which is concave in side view, is formed.

[0037] Subsequently, the extension portion 125 is drilled to form the access holes 35. Similarly, the extended portion 124 is drilled to form the first shaft hole 27A, the second shaft hole 27B, the first insertion holes 28A and the second insertion holes 28B. In addition, the material 113 is formed with, for example, internal oil passages 31 for each carrier, internal oil passages 36 for each cylinder, and connecting oil passages 37 by drilling. The carrier 13 is thus manufactured.

[0038] Next, the lubrication structure of the planetary gear device 10 of this embodiment 1 will be described. The oil supplied to the planetary gear device 10 flows through the main oil passage 16 and, due to the centrifugal force of the rotation of the shaft member 12, etc., enters the carrier internal oil passage 31 via the branch oil passage 17 from the main oil passage 16. The oil in the carrier internal oil passage 31 further flows through the shaft internal oil passage 21 and enters the discharge oil passage 22. The oil that enters the discharge oil passage 22 is supplied from the discharge oil passage 22 to the outer circumference of the pinion shaft 14, lubricating the needle bearing 23, etc. The oil also lubricates the meshing portion between the sun gear 11 and the large pinion gear 15A via the branch oil passage 17 and the second shaft hole 27B, and lubricates the thrust washer 29 between the pinion gear 15 and the second wall portion 24B. Furthermore, the oil flows through the main oil passages of other shaft members and enters the in-cylinder oil passage 36, lubricating the thrust washer 29 between the pinion gear 15 and the first wall portion 24A from the in-cylinder oil passage 36, and also lubricating the meshing portion between the sun gear 11 and the large pinion gear 15A through the connecting oil passage 37. The sliding portion between the pinion shaft 14 and the pinion gear 15 (needle bearing 23), the sliding portion between the pinion gear 15 and each wall portion 24 (thrust washer 29), the meshing portion between the sun gear 11 and the large pinion gear 15A, and the meshing portion between the small pinion gear 15B and the ring gear may also be lubricated by oil supply means such as an oil jet (not shown) as needed.

[0039] The oil is agitated by the rotation of the pinion gear 15, sun gear 11, and ring gear, thereby lubricating the lubrication space 40 on the radially outer side of the shaft member 12. In this embodiment 1, the connecting portion 25 is positioned radially inward from the pinion shaft 14, and unlike conventional designs, there is no connecting portion 25 between adjacent pinion gears 15 (each pinion shaft 14) in the circumferential direction. In other words, there is no connecting portion 25 in the lubrication space 40. Therefore, the oil does not accumulate in contact with the connecting portion 25 in the lubrication space 40 and is smoothly discharged from the lubrication space 40. Thus, it is possible to prevent an increase in the oil agitation resistance (agitation loss, power loss) in the planetary gear device 10, and to avoid a deterioration in fuel efficiency.

[0040] As described above, the planetary gear device 10 of this embodiment 1 includes a sun gear 11, a shaft member 12 that can rotate integrally with the sun gear 11, a pinion gear 15 that meshes with the sun gear 11, a pinion shaft 14 that rotatably supports the pinion gear 15, and a carrier 13 that can rotate relative to the axis of the shaft member 12. The carrier 13 has a pair of wall portions 24 that are spaced apart and facing each other in the axial direction of the shaft member 12, and a connecting portion 25 that extends in the axial direction and connects the wall portions 24. Both ends of the pinion shaft 14 in the axial direction are supported by the wall portions 24. The connecting portion 25 is positioned inward from the pinion shaft 14 in the radial direction of the shaft member 12. This makes it possible to avoid the oil supplied to the planetary gear device 10 coming into contact with the connecting portion 25 at the radial position where the pinion shaft 14 is located, thereby reducing the resistance to oil agitation.

[0041] In this embodiment 1, the pair of wall portions 24 and connecting portion 25 are integrated without welding. The carrier 13 has a split groove 26 that is concavely recessed towards the connecting portion 25 between the pair of wall portions 24. The planetary gear device 10 of this embodiment 1 is manufactured by pressing a tool against the cylindrical material 113 from the radial outside, splitting the material 113 and forming the split groove 26. This allows the pair of wall portions 24 and connecting portion 25 of the carrier 13 to be easily manufactured while forming the split groove 26 by splitting. In particular, since the pair of wall portions 24 and connecting portion 25 are integrated without welding, the number of parts does not increase, and costs can be reduced.

[0042] Furthermore, in this embodiment 1, the pinion gear 15 includes a large pinion gear 15A that meshes with the sun gear 11, and a small pinion gear 15B that has a smaller diameter than the large pinion gear 15A and is connected coaxially with the large pinion gear 15A. The connecting portion 25 includes a cylindrical portion 33 arranged inside the small pinion gear 15B, and a plurality of pieces 34 that face each other in the circumferential direction of the shaft member 12, with an access hole 35 that allows meshing between the sun gear 11 and the large pinion gear 15A. With this configuration, even if the connecting portion 25 is located on the side where the sun gear 11 is located, the sun gear 11 and the pinion gear 15 can be meshed through the access hole 35. As a result, the configuration of the planetary gear device 10 can be simplified, miniaturized, and lightened (reduced inertial mass).

[0043] [Other embodiments of this disclosure] Embodiment 1 disclosed herein should be considered in all respects to be illustrative and not restrictive. In the first embodiment described above, no oil receiver or the like was provided at the radially outer end of the lubrication space. In contrast, in other embodiments, an oil receiver or the like may be provided at the radially outer end of the lubrication space. In the first embodiment described above, the carrier was formed by integrally creating a pair of walls and connecting parts by splitting the material. In contrast, according to other embodiments, the carrier may be formed by integrally creating a pair of walls and connecting parts by cutting the material. Alternatively, the carrier may be formed by splitting or cutting a disc-shaped material. In the first embodiment described above, the carrier was provided with one connecting portion, and this single connecting portion connected the centers of each wall section. In contrast, according to other embodiments, the carrier may be provided with multiple connecting portions, and each connecting portion may be arranged at circumferential intervals in a location radially outside the center of each wall section and radially inside each pinion shaft, connecting the respective sections. In the first embodiment described above, four pinion gears were provided in the planetary gear device. In contrast, according to other embodiments, the number of pinion gears provided in the planetary gear device may be 1 to 3, or 5 or more. In the first embodiment described above, the carrier was arranged to be rotatable relative to the shaft member around its axis. In contrast, according to other embodiments, the carrier may be fixed to the shaft member in a manner that prevents relative rotation. [Explanation of Symbols]

[0044] 10...Planetary gear mechanism 11... Sangiya 12...Shaft member 13…Career 14...Pinion shaft 15... Pinion gear 15A...Large pinion gear 15B... Small pinion gear 16…Main oilway 17… Branch oil channel 18... Sleeves 21...Shaft oil passage 22...Drain oil path 23... Needle bearing 24...Wall part 24A…1st wall part 24B…Second wall part 25...Connection part 26...Cleft groove 27A…1st shaft hole 27B…Second shaft hole 28A…First insertion hole 28B...Second insertion hole 29…Thrust washer 31… Oil passages within carriers 32...Plug material 33...Cylindrical section 34... Part 35…Access port 36...Cylinder oil passage 37…Connecting oil road 40...Lubrication space 113...Materials 124...Expansion Department 125...Extending part 200... type 224... Guard section 225...Column part 310…1st tool 320…Second tool R... Rotation axis

Claims

1. Sangia and, A shaft member that can rotate integrally with the sun gear, A pinion gear that meshes with the aforementioned sun gear, A pinion shaft that rotatably supports the aforementioned pinion gear, Equipped with a career, The carrier has a pair of wall portions that are spaced apart and facing each other in the axial direction of the shaft member, and a connecting portion that extends in the axial direction and connects the wall portions together. The axial ends of the pinion shaft are each supported by the wall portion. The aforementioned connecting portion is positioned inward of the pinion shaft in the radial direction of the shaft member in a planetary gear device.

2. The pair of wall portions and the connecting portion are integrated without welding. The planetary gear device according to claim 1, wherein the carrier has a split groove between the pair of wall portions that is concave toward the connecting portion.

3. The pinion gear comprises a large pinion gear that meshes with the sun gear, and a small pinion gear that has a smaller diameter than the large pinion gear and is connected coaxially with the large pinion gear. The planetary gear device according to claim 2, wherein the connecting portion has a cylindrical portion disposed inside the small pinion gear and a plurality of pieces facing each other in the circumferential direction of the shaft member, with an access hole that allows the sun gear and the large pinion gear to mesh.

4. A method for manufacturing a planetary gear device according to claim 2 or claim 3, A method for manufacturing a planetary gear device, comprising the step of pressing a tool against a cylindrical or disc-shaped material from the radially outer side to split the material and form the split groove.

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