JP2008267486A - Planetary gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planetary gear wherein noises made by resonance of pinion shafts are reduced by so constituting the gear that resonance frequencies of the plurality of pinion shafts are made different from each other. <P>SOLUTION: The planetary gear 8a includes a plurality of pinion gears 31, and a plurality of pinion shafts 45a, 45b, 45c supporting the pinion gears 31 respectively. The pinion shafts 45a, 45b, 45c have axially extended holes 46a, 46b, 46c in the insides respectively. Out of the plurality of the pinion shafts 45a, 45b, 45c, the shape of the axial hole of at least a pinion shaft is different from the shapes of the axial holes of the other pinion shafts 45a, 45b, 45c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planetary gear device, and more particularly to a planetary gear device including an oil passage inside a pinion shaft that pivotally supports a pinion gear.

A conventional planetary gear device of this type includes a sun gear formed on a rotating shaft, a ring gear disposed outside the sun gear, and a pinion gear that is supported by the pinion shaft and meshes with the sun gear and the ring gear. Those are known (for example, see Patent Document 1). In this planetary gear device, a pinion shaft is formed with a first oil passage extending from one end portion thereof to the center portion thereof, and the first oil passage extends radially outward of the pinion shaft. A plurality of existing second oil passages communicate with each other, and the oil is supplied to a needle bearing interposed between the pinion gear and the pinion shaft through the first oil passage and the second oil passage. It is like that.
JP 2006-266305 A

  However, in such a conventional planetary gear device, when the vibration generated by the engagement between the pinion gear and the sun gear and the engagement between the pinion gear and the ring gear is transmitted from the pinion gear to the pinion shaft, the pinion shaft is bent and deformed. Resonance may occur in this mode. When the pinion shaft resonates, the amplitude of the vibration transmitted to the pinion shaft increases, the amplified vibration is transmitted to the case through the carrier, and the case vibration is radiated to the outside of the case as noise. There was a problem of entering the room.

  In particular, when the planetary gear device is mounted on a hybrid vehicle, the vibration generated by the meshing of the planetary gear device becomes a high frequency because the motor rotates at high speed, and the pinion shaft is likely to resonate. It has been a big problem to reduce the noise generated by the resonance.

  The present invention has been made in order to solve the conventional problems, and provides a planetary gear device capable of reducing noise generated by resonance of pinion shafts so that resonance frequencies of a plurality of pinion shafts do not coincide with each other. The purpose is to do.

  In order to achieve the above object, the planetary gear device according to the present invention is (1) a planetary gear device comprising a plurality of pinion gears and a plurality of pinion shafts that respectively support the pinion gears, wherein the plurality of pinion shafts are: An axial hole extending in the axial direction of the pinion shaft is provided therein, and the shape of the axial hole of at least one pinion shaft among the plurality of pinion shafts is the shape of the axial hole of another pinion shaft. It is composed of something different.

  With this configuration, the shapes of the axial holes of all the pinion shafts do not match, so the bending stiffness, natural frequency, and resonance frequency of the pinion shaft do not match. Therefore, the pinion shafts do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shaft can be reduced as compared with the case where all the pinion shafts resonate simultaneously.

  Further, in the planetary gear device having the configuration of (1), (2) the diameter of the axial hole of at least one pinion shaft among the plurality of pinion shafts is equal to the diameter of the axial hole of another pinion shaft. Consists of different things.

  With this configuration, since the diameters of the axial holes of all the pinion shafts do not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shaft do not match. Therefore, the pinion shafts do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shaft can be reduced as compared with the case where all the pinion shafts resonate simultaneously.

  Further, in the planetary gear device having the above configuration (1) or (2), (3) among the plurality of pinion shafts, the number of axial holes of at least one pinion shaft is the axial direction of the other pinion shafts. It is comprised from what differs from the number of holes.

  With this configuration, since the number of axial holes of all pinion shafts does not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shaft do not match. Therefore, the pinion shafts do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shaft can be reduced as compared with the case where all the pinion shafts resonate simultaneously.

  Further, in the planetary gear device having the configurations of (1) to (3), (4) the depth of the axial hole of at least one pinion shaft among the plurality of pinion shafts is the axis of another pinion shaft. It is comprised from what differs from the depth of a direction hole.

  With this configuration, since the depths of the axial holes of all the pinion shafts do not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shaft do not match. Therefore, the pinion shafts do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shaft can be reduced as compared with the case where all the pinion shafts resonate simultaneously.

  In the planetary gear device having the configurations (1) to (4), (5) the axial hole constitutes a part of the passage of the lubricating oil.

  With this configuration, noise generated by resonance of the pinion shaft can be reduced, and the axial hole of the pinion shaft can be used as an oil passage.

  The present invention can provide a planetary gear device that can reduce noise generated by resonance of pinion shafts so that the resonance frequencies of the plurality of pinion shafts do not coincide with each other.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1-4 is a figure which shows the planetary gear apparatus which concerns on one embodiment of this invention, and demonstrates the case where a planetary gear apparatus is applied to a hybrid vehicle.

  First, the configuration will be described. FIG. 1 is a skeleton diagram showing a power train 11 of a hybrid vehicle 1 of the FF (front engine front drive; engine front front wheel drive) type to which a planetary gear device according to an embodiment of the present invention is applied.

  As shown in FIG. 1, the power train 11 includes an engine 2, a transaxle 28, drive shafts 39 and 40, and drive wheels 41 and 42, and the crankshaft 2 a of the engine 2 extends in the width direction of the hybrid vehicle 1. And are arranged horizontally. A flywheel 3 is formed at the end of the crankshaft 2a. A transaxle 28 including a transmission mechanism, a power distribution mechanism, and a differential mechanism is attached to the outer wall of the engine 2, and a transaxle case 4 that is a casing of the transaxle 28 is made of a metal material, for example, These are manufactured by a die casting method using a material such as aluminum and have a hollow structure. In the internal space 4i of the transaxle case 4, an input shaft 5, a first motor / generator 6, a power distribution mechanism 7, a transmission mechanism 8, a second motor / generator 9, and the like are provided. The input shaft 5 rotates about the axis A1, and the clutch hub 10 is spline-fitted to the end on the crankshaft 2a side.

  A damper mechanism 12 that suppresses and absorbs torque fluctuation is provided between the flywheel 3 and the input shaft 5. The first motor / generator 6 is disposed outside the input shaft 5, and the second motor / generator 9 is disposed farther from the engine 2 than the first motor / generator 6. That is, the first motor / generator 6 is disposed between the engine 2 and the second motor / generator 9.

  The first motor / generator 6 and the second motor / generator 9 have a function as an electric motor driven by supplying electric power, that is, a power running function, and a function as a generator that converts mechanical energy into electric energy, that is, a regenerative function. It combines with. The first motor / generator 6 has a stator 13 fixed to the transaxle case 4 and a rotatable rotor 14.

  A hollow shaft 17 is attached to the outer periphery of the input shaft 5, and the input shaft 5 and the hollow shaft 17 are configured to be relatively rotatable. On the inner surface of the transaxle case 4, partition walls 4a, 4b, and 4c are provided. A bearing 15 is attached to the partition wall 4a, and a bearing 16 is attached to the partition wall 4b, and the hollow shaft 17 is rotatably held by the bearings 15 and 16.

  A power distribution mechanism 7 is provided between the first motor / generator 6 and the second motor / generator 9. The power distribution mechanism 7 includes a so-called single pinion type planetary gear unit 7a. That is, the planetary gear unit 7 a includes a sun gear 18, a ring gear 19 disposed concentrically with the sun gear 18, a plurality of pinion gears 20 that mesh with the sun gear 18 and the ring gear 19, and a carrier 21 that holds the pinion gear 20. is doing. The sun gear 18 is connected to the hollow shaft 17, and the carrier 21 is connected to the input shaft 5. The ring gear 19 is formed on the inner peripheral side of an annular member 22 disposed concentrically with the input shaft 5, and a counter drive gear 23 is formed on the outer peripheral portion of the annular member 22. The counter drive gear 23 is connected to drive wheels 41 and 42 via an intermediate shaft 37, a differential 38 and drive shafts 39 and 40.

  A connecting shaft 5a is concentrically connected to the input shaft 5, and the input shaft 5 and the connecting shaft 5a can rotate integrally. A hollow shaft 24 is rotatably attached to the outer peripheral portion of the connecting shaft 5 a, and the second motor / generator 9 is disposed on the outer peripheral portion of the hollow shaft 24. The second motor / generator 9 includes a stator 25 fixed to the transaxle case 4 and a rotatable rotor 26, and the rotor 26 is connected to the hollow shaft 24 so as to rotate integrally therewith. Yes. A bearing 35 is attached to the partition wall 4c on the inner surface of the transaxle case 4, and a bearing 36 is attached to an end of the transaxle case 4. The hollow shaft 24 is rotatably held by the bearings 35 and 36. ing.

  A speed change mechanism 8 is provided between the power distribution mechanism 7 and the second motor / generator 9. The transmission mechanism 8 includes a so-called single pinion type planetary gear unit 8a. That is, the planetary gear device 8 a includes a sun gear 29 that rotates integrally with the hollow shaft 24, a ring gear 30 that is disposed concentrically with the sun gear 29 and formed on the inner periphery of the annular member 22, the sun gear 29, and the ring gear. A plurality of pinion gears 31 that mesh with 30 and a carrier 32 that holds the pinion gears 31 are provided. The carrier 32 is fixed to the partition wall 4c so as not to rotate. The annular member 22 is rotatably held by a bearing 33 attached to the partition wall 4b and a bearing 34 attached to the partition wall 4c.

  In the power train 11, torque output from the engine 2 is transmitted to the carrier 21 via the input shaft 5. The torque transmitted to the carrier 21 is transmitted to the drive wheels 41 and 42 via the ring gear 19, the annular member 22, the counter drive gear 23, and the like. Further, when the torque of the engine 2 is transmitted to the carrier 21, the first motor / generator 6 can function as a generator, and the generated electric power can be charged in a power storage device (not shown).

  In the power train 11, the second motor / generator 9 can be driven as an electric motor, and the power can be transmitted to the power distribution mechanism 7. When the power of the second motor / generator 9 is transmitted to the sun gear 29 through the hollow shaft 24, the carrier 32 is fixed to the partition wall 4c as described above and acts as a reaction force element. Rotation occurs without revolution, and the torque of each pinion gear 31 is transmitted to the ring gear 30. The rotational speed of the ring gear 30 is reduced with respect to the rotational speed of the sun gear 29, and the rotational direction of the ring gear 30 is opposite to the rotational direction of the sun gear 29.

  Further, the power of the engine 2 and the power of the second motor / generator 9 are input to the power distribution mechanism 7 and combined, and the combined power is transmitted to the drive wheels 41 and 42. Therefore, the hybrid vehicle 1 having the power train 11 can transmit the torque of at least one of the engine 2 or the second motor / generator 9 to the drive wheels 41 and 42.

  FIG. 2 is a cross-sectional view showing transaxle 28 of hybrid vehicle 1 having planetary gear unit 8a according to an embodiment of the present invention.

  As shown in FIG. 2, the carrier 32 includes an annular holder 43 and an annular plate 44, and the holder 43 and the plate 44 are connected by a pinion shaft 45.

  The plurality of pinion shafts 45 are arranged at a predetermined interval on the same circumference around the axis A1. Each pinion shaft 45 is formed with an axial hole 46 as an oil passage extending in the axial direction. Further, a radial hole 47 as an oil passage that penetrates each pinion shaft 45 in the radial direction and extends radially outward of the axis A1 is formed at a substantially central portion in the axial direction of each pinion shaft 45, and the radial direction The hole 47 communicates with the axial hole 46. A needle bearing 48 is interposed between the pinion shaft 45 and the pinion gear 31, and the pinion gear 31 can rotate around the pinion shaft 45. The oil in the axial hole 46 is supplied to the needle bearing 48 through the radial hole 47 by centrifugal force acting on the oil when the pinion gear 31 rotates about the axis A1.

  The oil supplied to the needle bearing 48 is swept up by the rotation of the differential 38, the intermediate shaft 37, and the counter drive gear 23, enters the cavity 4j, flows down in the direction of arrow B in FIG. Supplied by entering.

  3 is an arrow view of the transaxle 28 shown in FIG. 2 as viewed from the AA direction.

  As shown in FIG. 3, an oil storage part 52 is formed in the internal space 4 i of the transaxle case 4, and the oil pump 49 removes the oil stored in the oil storage part 52 from each part in the transaxle case 4. To send to. As shown in FIG. 3, the carrier 32 holds three pinion shafts 45 at equal intervals.

  Next, the pinion shafts 45 are distinguished from the pinion shafts 45a, 45b, and 45c, and the pinion shafts 45a, 45b, and 45c are described. 4A, 4B, and 4C are sectional views of the pinion shafts 45a, 45b, and 45c, respectively.

  As shown in FIG. 4A, the pinion shaft 45a includes an axial hole 46a as an oil passage formed with a diameter D1 and a depth L1 from the one end of the pinion shaft 45a to the deepest portion along the axial direction. And an axial hole 46b formed with a diameter D1 and a depth L2 from the other end of the pinion shaft 45a to the deepest portion along the axial direction. That is, the pinion shaft 45a includes two axial holes 46a and 46b. The pinion shaft 45a includes a radial hole 47 that extends radially from the axial hole 46a in the pinion shaft 45a to the outside of the pinion shaft 45a. The radial hole 47 communicates with the axial hole 46a. ing.

  As shown in FIG. 4B, the pinion shaft 45b has an axial hole 46a as an oil passage formed with a diameter D1 and a depth L1 from the one end portion of the pinion shaft 45b to the deepest portion along the axial direction. I have. That is, unlike the pinion shaft 45a, the pinion shaft 45b does not include the axial hole 46b but includes one axial hole 46a. Further, the pinion shaft 45b includes a radial hole 47 that penetrates radially from the axial hole 46a in the pinion shaft 45b to the outside of the pinion shaft 45b. The radial hole 47 communicates with the axial hole 46a. ing.

  As shown in FIG. 4C, the pinion shaft 45c has an axial hole 46c as an oil passage formed with a diameter D2 and a depth L3 from the one end portion of the pinion shaft 45c along the axial direction to the deepest portion. I have. That is, unlike the pinion shaft 45a, the pinion shaft 45c does not include the axial hole 46b but includes one axial hole 46c. Further, the depth L3 to the deepest portion of the axial hole 46c is formed shorter than the depth L1 to the deepest portion of the axial hole 46a, and the diameter D2 of the axial hole 46c is set to the axial hole 46a, It is formed smaller than the diameter D1 of 46b. The pinion shaft 45c includes a radial hole 47 that penetrates radially from the axial hole 46c in the pinion shaft 45c to the outside of the pinion shaft 45c, and the radial hole 47 communicates with the axial hole 46c. ing.

  Here, the diameter D1 of the axial holes 46a and 46b is set larger than the diameter D2 of the axial hole 46c. Further, the depth L3 of the axial hole 46c is set shorter than the depth L1 of the axial hole 46a, and the depth L2 of the axial hole 46b is set shorter than the depth L3 of the axial hole 46c. Yes. Therefore, in the pinion shafts 45a, 45b, and 45c, the bending rigidity of the pinion shaft 45a having the two axial holes 46a and 46b is the lowest among the three, and the bending rigidity of the pinion shaft 45c having the axial hole 46c. Is the highest of the three. Further, the bending rigidity of the pinion shaft 45b having one axial hole 46a is higher than the bending rigidity of the pinion shaft 45a and lower than the bending rigidity of the pinion shaft 45c.

  Therefore, the natural frequency of the pinion shaft 45a is the lowest among the three, and the natural frequency of the pinion shaft 45c is the highest among the three. Further, the natural frequency of the pinion shaft 45b is higher than the natural frequency of the pinion shaft 45a and lower than the natural frequency of the pinion shaft 45c. Further, when external vibration is applied to the pinion shafts 45a, 45b, 45c, the resonance frequency generated in the pinion shafts 45a, 45b, 45c is a value close to the natural frequency of each of the pinion shafts 45a, 45b, 45c. Become.

  As a result, the resonance frequencies generated in the pinion shafts 45a, 45b, and 45c due to vibration generated from the meshing portion of the pinion gear 31 and the ring gear 30 or the meshing portion of the pinion gear 31 and the sun gear 29 are the pinion shafts 45a, 45b, and 45c. Each one will be different. Specifically, the resonance frequency of the pinion shaft 45a is the lowest among the three, and the resonance frequency of the pinion shaft 45c is the highest among the three. In addition, the resonance frequency of the pinion shaft 45b is higher than the resonance frequency of the pinion shaft 45a and lower than the resonance frequency of the pinion shaft 45c.

  Next, the operation of the planetary gear device 8a configured as described above will be described. In the planetary gear unit 8a, during the operation of the hybrid vehicle 1, vibrations generated from the meshing portion of the pinion gear 31 and the ring gear 30 or the meshing portion of the pinion gear 31 and the sun gear 29 are generated on the pinion shafts 45a, 45b, and 45c. The pinion shafts 45a, 45b and 45c are vibrated. The pinion shafts 45a, 45b, 45c resonate when the frequency of the applied vibration is near the natural frequency of the pinion shafts 45a, 45b, 45c. Specifically, the pinion shaft 45a resonates at a lower frequency than the pinion shafts 45b and 45c, the pinion shaft 45c resonates at a higher frequency than the pinion shafts 45a and 45b, and the pinion shaft 45b Resonance occurs at a frequency higher than 45a and lower than that of the pinion shaft 45c. For this reason, since the resonance frequencies of the pinion shafts 45a, 45b, and 45c do not match, the pinion shafts 45a, 45b, and 45c do not resonate at the same time.

  As described above, in the planetary gear device 8a according to the present embodiment, the pinion shaft 45a has axial holes 46a and 46b extending in the axial direction of the pinion shaft 45a, and the pinion shaft 45b is pinion shaft. The pinion shaft 45c has an axial hole 46c extending in the axial direction of the pinion shaft 45c, and has a plurality of pinion shafts 45a, 45b. 45c, the axial holes 46a and 46b of the pinion shaft 45a are configured to be different in shape from the axial holes 46c of the pinion shaft 45c.

  For this reason, since the shapes of the axial holes 46a, 46b, 46c of the pinion shafts 45a, 45b, 45c do not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shafts 45a, 45b, 45c do not match. Therefore, the pinion shafts 45a, 45b, and 45c do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shafts 45a, 45b, 45c can be reduced as compared with the case where the pinion shafts 45a, 45b, 45c all resonate simultaneously.

  Further, in the planetary gear device 8a according to the present embodiment, of the pinion shafts 45a, 45b, 45c, the diameter D2 of the axial hole 46c of the pinion shaft 45c is equal to the diameter D1 of the axial hole 46a of the pinion shaft 45b. Configured differently.

  For this reason, since the diameters of the axial holes 46a, 46b, and 46c of the pinion shafts 45a, 45b, and 45c do not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shafts 45a, 45b, and 45c do not match. Therefore, the pinion shafts 45a, 45b, and 45c do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shafts 45a, 45b, 45c can be reduced as compared with the case where the pinion shafts 45a, 45b, 45c all resonate simultaneously.

  Further, in the planetary gear device 8a according to the present embodiment, among the pinion shafts 45a, 45b, 45c, the number of the axial holes 46a, 46b of the pinion shaft 45a is equal to the number of the axial holes 46a of the pinion shaft 45b. The number of axial holes 46c of the pinion shaft 45c is different from that of the pinion shaft 45c. That is, the pinion shaft 45a has two axial holes 46a and 46b, whereas the pinion shaft 45b has one axial hole 46a, and the pinion shaft 45c has one axial hole 46c. have.

  For this reason, since the number of axial holes 46a, 46b, 46c of the pinion shafts 45a, 45b, 45c does not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shafts 45a, 45b, 45c do not match. Therefore, the pinion shafts 45a, 45b, and 45c do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shafts 45a, 45b, 45c can be reduced as compared with the case where the pinion shafts 45a, 45b, 45c all resonate simultaneously.

  In the planetary gear device 8a according to the present embodiment, of the pinion shafts 45a, 45b, 45c, the depth L1 of the axial hole 46a of the pinion shaft 45a is the depth of the axial hole 46c of the pinion shaft 45c. It is configured to be different from L3. That is, the depth L1 of the axial hole 46a of the pinion shaft 45a is deeper than the depth L3 of the axial hole 46c of the pinion shaft 45c.

  For this reason, since the depths of the axial holes 46a, 46b, 46c of the pinion shafts 45a, 45b, 45c do not match, the bending rigidity, natural frequency, and resonance frequency of the pinion shafts 45a, 45b, 45c do not match. Therefore, the pinion shafts 45a, 45b, and 45c do not all resonate at the same time. As a result, the noise generated by the resonance of the pinion shafts 45a, 45b, 45c can be reduced as compared with the case where the pinion shafts 45a, 45b, 45c all resonate simultaneously.

  Further, in the planetary gear device 8a according to the present embodiment, the axial hole 46a of the pinion shaft 45a, the axial hole 46a of the pinion shaft 45b, and the axial hole 46c of the pinion shaft 45c communicate with the radial hole 47, respectively. In addition, it is a part of an oil passage for supplying oil to the needle bearing 48. That is, the axial hole 46a of the pinion shafts 45a and 45b and the axial hole 46c of the pinion shaft 45c are formed as a part of the oil passage, and the purpose is not to match the resonance frequencies of the pinion shafts 45a, 45b and 45c. It's not just a new one.

  Therefore, noise generated by resonance of the pinion shafts 45a, 45b, and 45c can be reduced, and the axial hole 46a of the pinion shaft 45a, the axial hole 46a of the pinion shaft 45b, and the axial hole 46c of the pinion shaft 45c. Can be used as an oil passage.

  In addition, although the planetary gear apparatus 8a mentioned above demonstrated the structure which has pinion shaft 45a, 45b, 45c, the planetary gear apparatus 7a is similarly comprised so that the resonance frequency of all the pinion shafts may not correspond. Further, the planetary gear devices 7a and 8a have a single pinion type configuration, but the present invention can also be applied to a planetary gear device having a double pinion type configuration. In that case, the bending rigidity, the natural frequency, and the resonance frequency may be made different by changing the shape of the axial hole in both the pinion gear meshing with the ring gear and the pinion gear meshing with the sun gear.

  In the present embodiment, the planetary gear device 8a has three pinion shafts 45a, 45b, and 45c, and the pinion shafts 45a, 45b, and 45c have different bending stiffnesses. By configuring the bending rigidity of at least one of the three pinion shafts 45a, 45b, and 45c to be different from the bending rigidity of the other pinion shafts, the three pinion shafts 45a, 45b, and 45c are caused to resonate simultaneously. Can not be.

  In the present embodiment, the planetary gear device 8a has three pinion shafts 45a, 45b, and 45c. However, the number of pinion shafts is not limited to three, for example, five. Also good. In this case as well, the bending rigidity of at least one of the five pinion shafts may be different from the bending rigidity of the other pinion shafts so that all the five pinion shafts do not resonate simultaneously.

  As described above, the present invention has an effect that noise generated by resonance of a pinion shaft can be reduced by preventing resonance frequencies of a plurality of pinion shafts from matching, and a pinion that supports a pinion gear is supported. It is useful for all planetary gear devices having an oil passage inside the shaft.

1 is a skeleton diagram showing a power train of an FF (front engine front drive; engine front front wheel drive) hybrid vehicle to which a planetary gear device according to an embodiment of the present invention is applied. FIG. It is sectional drawing which shows the transaxle of the hybrid vehicle which has the planetary gear apparatus which concerns on one embodiment of this invention. FIG. 3 is an arrow view seen from the AA direction of the transaxle shown in FIG. 2. (A), (b), (c) is sectional drawing of the pinion shaft of the planetary gear apparatus based on this invention.

Explanation of symbols

8a Planetary gear unit 31 Pinion gear 45 Pinion shaft 46, 46a, 46b, 46c Axial direction hole

Claims (5)

In a planetary gear device comprising a plurality of pinion gears and a plurality of pinion shafts that respectively support the pinion gears, the plurality of pinion shafts have an axial hole extending in the axial direction of the pinion shaft inside. A planetary gear device characterized in that among the plurality of pinion shafts, the shape of the axial hole of at least one pinion shaft is different from the shape of the axial hole of the other pinion shaft. The planetary gear device according to claim 1, wherein a diameter of an axial hole of at least one pinion shaft among the plurality of pinion shafts is different from a diameter of an axial hole of another pinion shaft. The planetary gear according to claim 1 or 2, wherein the number of axial holes of at least one pinion shaft among the plurality of pinion shafts is different from the number of axial holes of other pinion shafts. apparatus. The depth of the axial hole of at least one pinion shaft among the plurality of pinion shafts is different from the depth of the axial hole of other pinion shafts. The planetary gear device according to the item. The planetary gear device according to any one of claims 1 to 4, wherein the axial hole constitutes a part of a passage for lubricating oil.