Planetary gear system

Abstract

This makes it possible to stabilize the axial position of the carrier in a planetary gear mechanism. [Solution] A planetary gear device is disclosed that can be placed in a case where oil is collected, comprising a planetary gear mechanism having a sun gear, a carrier and a ring gear, and fins attached to the carrier and rotating with the carrier, capable of scooping up oil when rotating, wherein the carrier rotatably supports a first pinion gear and a second pinion gear that are aligned axially and have different diameters, the first pinion gear and the second pinion gear have helical teeth that generate thrust loads in a direction that cancels out each other when rotating, and the fins are formed such that the force received from the oil when scooping up the oil has an axial component to the planetary gear mechanism.

Description

Technical Field

[0001] The present disclosure relates to a planetary gear device.

Background Art

[0002] In order to reduce the burden on bearings, a technique is known in which a gear set of a planetary gear device has helical teeth and is configured to cancel out the thrust load generated by the gear set.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Due to manufacturing tolerances, assembly tolerances, etc., it is difficult to establish a relationship in which the thrust loads generated by the gear set exactly cancel each other out. Therefore, in the conventional technology as described above, when the thrust load generated by the gear set is significantly greater than 0, the direction of the thrust load generated by the gear set is reversed during vehicle acceleration and deceleration (similarly during power running and regeneration), and the axial position of the gear set fluctuates and is unstable.

[0005] Therefore, on one aspect, an object of the present disclosure is to stabilize the axial position of a carrier in a planetary gear mechanism.

Means for Solving the Problems

[0006] On one aspect, a planetary gear device that can be disposed in a case where oil accumulates, a planetary gear mechanism including a sun gear, a carrier, and a ring gear, and fins that are attached to the carrier and rotate together with the carrier and can scrape up oil during rotation. The carrier rotatably supports a first pinion gear and a second pinion gear that are aligned in the axial direction and have different diameters. The first pinion gear and the second pinion gear have helical teeth that generate thrust loads in directions that cancel each other out during rotation. A planetary gear device is provided in which the fins are formed such that the force they receive from the oil when scooping up the oil has an axial component to the planetary gear mechanism. [Effects of the Invention]

[0007] In one aspect, this disclosure makes it possible to stabilize the axial position of the carrier in a planetary gear mechanism. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic top view diagram showing the mounting configuration of the vehicle's drive system. [Figure 2] This is a cross-sectional view of the main components of a vehicle's drive system. [Figure 2A] This is a skeleton diagram showing a vehicle drive system. [Figure 3] This is a perspective view showing the carrier and fins extracted from this embodiment. [Figure 4] This is a perspective view showing a part of a fin in its individual form. [Figure 5] This is a diagram illustrating the function of the fins, showing a cross-section of the fins along with a cross-section of a part of the carrier. [Figure 6] This is a diagram showing a comparative example for comparison purposes. [Modes for carrying out the invention]

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, shapes and other details in the drawings may be partially exaggerated for illustrative purposes. Also, for clarity, in some cases, only a portion of parts with the same attribute are assigned reference numerals in the drawings.

[0010] In the following description, the orientation of each component refers to its orientation when assembled to the vehicle drive unit 100. Furthermore, the terms related to the dimensions, orientation, and position of each component are concepts that include variations due to manufacturing tolerances.

[0011] In this specification, "drive connection" refers to a state in which two rotating elements are connected in a manner that enables the transmission of a driving force (synonymous with torque), and includes a state in which the two rotating elements are connected so as to rotate as a whole, or a state in which the two rotating elements are connected in a manner that enables the transmission of a driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at a variable speed (e.g., shafts, gear mechanisms, belts, chains, etc.). In addition, the transmission members may include engagement devices that selectively transmit rotation and driving force (e.g., friction engagement devices, meshing engagement devices, etc.).

[0012] In this specification, the term "rotating electric machine" is used to encompass the concept of motors, generators, and motor-generators that perform both motor and generator functions as needed. Furthermore, in this specification, with regard to the arrangement of two members, "overlapping in a specific viewing direction" means that when a virtual line parallel to the line of sight is moved in each direction perpendicular to that virtual line, there exists at least a portion of the region where the virtual line intersects both members. Furthermore, in this specification, with regard to the arrangement of two members, "overlapping arrangement regions in a specific direction" means that at least a portion of the arrangement region of one member in a specific direction is contained within the arrangement region of the other member in a specific direction.

[0013] Figure 1 is a schematic top view showing the mounting state of the vehicle drive unit 100 in the vehicle VC. Figure 2 is a cross-sectional view of the main part of the vehicle drive unit 100. Figure 2A is a skeleton view showing the vehicle drive unit 100. Note that the fins 80, which will be described later, are shown in a very schematic manner in Figure 2.

[0014] The vehicle drive unit 100 may be mounted on the vehicle VC in a orientation such that the front side L1 (front side in the vehicle longitudinal direction L) and the rear side L2 (rear side in the vehicle longitudinal direction L) are at the front. As shown in Figure 1, the vehicle drive unit 100 may be mounted in the vehicle VC in the front side L1 of the vehicle longitudinal direction L. When the vehicle drive unit 100 is mounted in the vehicle VC in the rear side L2 of the vehicle longitudinal direction L, the pair of wheels W driven by the vehicle drive unit 100 may be, for example, a pair of left and right rear wheels.

[0015] When the vehicle VC is equipped with a pair of left and right front wheels and a pair of left and right rear wheels, the vehicle may be configured such that the vehicle not driven by the vehicle drive unit 100 (in the example shown in Figure 1, the pair of left and right rear wheels) is driven by a drive unit other than the vehicle drive unit 100. The drive unit other than the vehicle drive unit 100 may be, for example, a drive unit configured to transmit the output torque of an internal combustion engine to the pair of wheels to be driven, a drive unit configured to transmit the output torque of a rotating electric machine (a rotating electric machine other than the rotating electric machine 1 provided in the vehicle drive unit 100) to the pair of wheels to be driven, or a drive unit configured to transmit the output torque of both an internal combustion engine and a rotating electric machine (a rotating electric machine other than the rotating electric machine 1 provided in the vehicle drive unit 100) to the pair of wheels to be driven. The drive unit other than the vehicle drive unit 100 may also be a drive unit with the same configuration as the vehicle drive unit 100.

[0016] In this embodiment, as schematically shown in FIGS. 1 to 2A, the vehicle drive device 100 includes a rotating electric machine 1, a pair of output members 6 respectively drivingly connected to a pair of wheels W (see FIG. 1), and a transmission mechanism 3 that transmits a driving force between the rotating electric machine 1 and the pair of output members 6. The vehicle drive device 100 further includes a case 2 that houses the rotating electric machine 1. The case 2 also houses the pair of output members 6 and the transmission mechanism 3. In this embodiment, as shown in FIG. 2, the case 2 forms a motor housing chamber S1 that houses the rotating electric machine 1 and a transmission mechanism housing chamber S2 that houses the transmission mechanism 3.

[0017] One of the pair of output members 6, the first output member 61, is drivingly connected to one of the pair of wheels W, the first wheel W1, and the other of the pair of output members 6, the second output member 62, is drivingly connected to the other of the pair of wheels W, the second wheel W2. As shown in FIG. 1, the vehicle VC on which the vehicle drive device 100 is mounted includes a first drive shaft 63 that rotates integrally with the first wheel W1 and a second drive shaft 64 that rotates integrally with the second wheel W2. The first drive shaft 63 is connected to the first wheel W1 via, for example, a constant velocity joint, and the second drive shaft 64 is connected to the second wheel W2 via, for example, a constant velocity joint. Then, the first output member 61 is connected to the first drive shaft 63 so as to rotate integrally with the first drive shaft 63, and the second output member 62 is connected to the second drive shaft 64 so as to rotate integrally with the second drive shaft 64.

[0018] The vehicle drive device 100 transmits the output torque of the rotary electric machine 1 to a pair of wheels W via a pair of output members 6, causing the vehicle VC equipped with the vehicle drive device 100 to travel. That is, the rotary electric machine 1 is a driving force source for the pair of wheels W. The pair of wheels W are a pair of left and right wheels on the vehicle VC (for example, a pair of left and right front wheels or a pair of left and right rear wheels). The rotary electric machine 1 may be, for example, an AC rotary electric machine driven by three-phase AC. The rotary electric machine 1 is electrically connected to a battery BA (including a power storage device such as a capacitor) via an inverter device (not shown) that performs power conversion between DC power and AC power, receives power supply from the battery BA and performs power running, or supplies the power generated by the inertial force of the vehicle VC or the like to the power storage device for power storage.

[0019] As shown in FIG. 2, the rotary electric machine 1 and the pair of output members 6 are arranged separately on two axes (specifically, the first axis C1 and the second axis C2) parallel to each other. Specifically, the rotary electric machine 1 is arranged on the first axis C1, and the pair of output members 6 are arranged on a second axis C2 different from the first axis C1. The first axis C1 and the second axis C2 are axes (virtual axes) arranged parallel to each other. The transmission mechanism 3 includes an output gear (ring gear) 30 drivingly connected to at least one of the pair of output members 6 coaxially with the pair of output members 6 (that is, on the second axis C2).

[0020] As shown in Figure 1, the vehicle drive unit 100 is mounted on the vehicle VC with its axial direction A aligned with the left-right direction of the vehicle. The axial direction A is parallel to the first axis C1 and the second axis C2, in other words, it is the common axial direction between the first axis C1 and the second axis C2. That is, the axial direction A is the direction in which the rotation axis of the rotating electric machine 1 extends, and also the direction in which the rotation axes of the pair of output members 6 extend. Here, one side of the axial direction A is called the axial first side A1, and the other side of the axial direction A (opposite to the axial first side A1 in the axial direction A) is called the axial second side A2. The axial first side A1 is the side in the axial direction A on which the rotating electric machine 1 is positioned relative to the transmission mechanism 3. As shown in Figure 2, the first output member 61 is the output member 6 of the pair of output members 6 that is positioned on the axial first side A1, and the second output member 62 is the output member 6 of the pair of output members 6 that is positioned on the axial second side A2.

[0021] As shown in Figure 1, the vehicle drive unit 100 may be mounted on the vehicle VC with the axial first side A1 on the right side of the vehicle and the axial second side A2 on the left side of the vehicle. In this case, the first wheel W1 to which the first output member 61 is driven is the right wheel, and the second wheel W2 to which the second output member 62 is driven is the left wheel. Figure 1 assumes that the vehicle drive unit 100 is a front-wheel drive system that drives a pair of left and right front wheels. Therefore, in the example shown in Figure 1, the first wheel W1 is the right front wheel, and the second wheel W2 is the left front wheel.

[0022] As shown in Figure 2, the rotating electric machine 1 comprises a rotor 10 and a stator 11. The stator 11 is fixed to the case 2, and the rotor 10 is supported by the case 2 so as to be rotatable relative to the stator 11. The rotating electric machine 1 may be an inner rotor type, in which case the rotor 10 may be positioned radially inward relative to the stator 11, and overlapping with the stator 11 in a radial view along the radial direction. Here, the radial direction is the radial direction with respect to the first axis C1, in other words, the radial direction with respect to the rotation axis of the rotating electric machine 1.

[0023] The stator 11 comprises a stator core 12 and coil end portions 13 that protrude from the stator core 12 in the axial direction A. A coil is wound around the stator core 12, and the portion of the coil that protrudes from the stator core 12 in the axial direction A forms the coil end portions 13. The coil end portions 13 are formed on both sides of the stator core 12 in the axial direction A.

[0024] The transmission mechanism 3 includes a planetary gear mechanism 34 that functions as a reduction mechanism in the power transmission path between the rotating electric machine 1 and the output gear 30.

[0025] In this embodiment, the planetary gear mechanism 34 is arranged coaxially with the rotating electric machine 1. The output gear (carrier) 342 of the planetary gear mechanism 34 meshes radially with the output gear 30 of the differential gear mechanism 5. Such a vehicle drive system 100 can have a compact configuration consisting of two shafts (first shaft C1 and second shaft C2). In a modified example, the vehicle drive system 100 may have three or more shafts.

[0026] In this embodiment, the planetary gear mechanism 34 is arranged coaxially with the rotating electric machine 1 (i.e., on the first axis C1) in a manner that drives and connects it to the rotating electric machine 1. The input member 16 that meshes with the sun gear 341 of the planetary gear mechanism 34 is connected to the rotor 10 so as to rotate integrally with the rotor 10. In the example shown in Figure 2, the vehicle drive unit 100 includes a rotor shaft 15 to which the rotor 10 is fixed, and the input member 16 is connected to the rotor shaft 15 so as to rotate integrally with the rotor shaft 15. Specifically, the axial first side A1 portion of the input member 16 may be connected (in this case, by spline connection) to the axial second side A2 portion of the rotor shaft 15. In contrast to this configuration, the rotor shaft 15 and the input member 16 of the vehicle drive unit 100 can also be formed integrally as a single piece.

[0027] In this embodiment, the carrier 342 rotatably supports a first pinion gear 3431 and a second pinion gear 3432, which rotate integrally with each other. The first pinion gear 3431 meshes with the ring gear 344. The first pinion gear 3431 is formed to have a smaller diameter than the second pinion gear 3432. The second pinion gear 3432 meshes with the sun gear 341. The second pinion gear 3432 may have a shorter shaft length than the first pinion gear 3431.

[0028] In this embodiment, the first pinion gear 3431 is positioned axially to the first side A1 of the second pinion gear 3432. Each of the second pinion gear 3432 and the first pinion gear 3431 rotates (rotates) around its own axis and also revolves (orbits) around the sun gear 341 together with the carrier 342. Multiple second pinion gears 3432 and first pinion gears 3431 are provided at intervals from each other along their respective orbital trajectories. The carrier 342 is connected to the transmission gear 3421 that meshes with the output gear 30 so as to rotate integrally with it. The ring gear 344 is fixed to the case 2.

[0029] Furthermore, the transmission mechanism 3 further includes a differential gear mechanism 5. The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to a pair of output members 6. The differential gear mechanism 5 may be arranged coaxially with the pair of output members 6 (i.e., on the second shaft C2). The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to the output gear 30 to the pair of output members 6. That is, the output gear 30 is driven and connected to both of the pair of output members 6 via the differential gear mechanism 5. The differential gear mechanism 5 may be a bevel gear type differential gear mechanism, and the output gear 30 may be connected to the differential case portion 50 of the differential gear mechanism 5 so as to rotate integrally with the differential case portion 50.

[0030] In the example shown in Figure 2, the differential gear mechanism 5 distributes the rotation of the output gear 30 to a first side gear 51 and a second side gear 52. The first side gear 51 rotates integrally with the first output member 61, and the second side gear 52 rotates integrally with the second output member 62. The first side gear 51 may be formed from a separate component from the components constituting the first output member 61 (here, the shaft member), and may be connected to the first output member 61 (here, spline connected) so as to rotate integrally with the first output member 61. At least the portion of the first output member 61 on the axial first side A1 is formed in a cylindrical shape (specifically, a cylindrical shape) extending in the axial direction A, and the first drive shaft 63 (see Figure 1) may be inserted into the interior of the first output member 61 (the space surrounded by the inner circumferential surface) from the axial first side A1. The second output member 62 may also be connected to the second side gear 52. The second output member 62 may also be realized by a second drive shaft 64.

[0031] Next, with reference to Figure 3 and subsequent figures, further characteristic configurations of this embodiment will be described.

[0032] Figure 3 is a perspective view showing the carrier 342 and fin 80 extracted from this embodiment. Figure 4 is a perspective view showing a part of the fin 80 in its individual state. Figure 5 is an explanatory diagram of the function of the fin 80, showing a cross-section of the fin 80 along with a cross-section of a part of the carrier 342. In Figure 5, for the sake of explanation, the cross-section of the carrier 342 corresponds to a cross-section cut by a vertical plane passing through the first axis C1, and the cross-section of the fin 80 corresponds to a cross-section cut by a plane parallel to the vertical plane passing through the first axis C1. Figure 6 is a diagram showing a comparative example for comparison, and schematically shows the configuration of the comparative example, corresponding to Figure 5.

[0033] In this embodiment, the first pinion gear 3431 and the second pinion gear 3432 each form a helical gear and have helical teeth on their outer surfaces. The first pinion gear 3431 and the second pinion gear 3432 generate a thrust load during rotation due to the helical teeth. In this embodiment, the twisting direction of the helical teeth of the second pinion gear 3432 and the first pinion gear 3431 is set so that the thrust load received by the first pinion gear 3431 from the ring gear 344 and the thrust load received by the second pinion gear 3432 from the sun gear 341 are in opposite directions. Specifically, the first pinion gear 3431 and the second pinion gear 3432 are formed so that the twisting direction of their helical teeth is the same. In this embodiment, the thrust loads generated during rotation due to the helical teeth of the first pinion gear 3431 and the second pinion gear 3432 cancel each other out. In this case, the support structure of the first pinion gear 3431 and the second pinion gear 3432 can be simplified and the rigidity of the carrier 342 can be reduced.

[0034] The helical teeth of the first pinion gear 3431 and the second pinion gear 3432 may be designed so that the thrust loads generated during rotation completely cancel each other out (i.e., become zero), or they may be designed so that a small thrust load remains even after cancellation. For example, if the shaft length of the first pinion gear 3431 is longer than that of the second pinion gear 3432, the thrust load received by the first pinion gear 3431 may be designed to be slightly larger than the thrust load received by the second pinion gear 3432. This is because when the shaft length is short, it tends to be more difficult to increase the helix angle compared to when the shaft length is long. The thrust load received by the helical teeth generally depends on the helix angle, etc. The helix angle is the angle at which the teeth of the gear are inclined with respect to the axis of the gear.

[0035] In this embodiment, a fin 80 is attached to the carrier 342. The fin 80 has an airfoil shape. The fin 80 is integrally fixed to the carrier 342 in such a manner that it rotates together with the carrier 342. For example, the fin 80 may be fixed to the carrier 342 by crimping or the like.

[0036] The fins 80 extend around the carrier 342, as shown in Figure 3. The fins 80 may be supported by a support portion 88 that has an annular shape when viewed in the axial direction, as shown in Figure 4. In the example shown in Figure 4, three fins 80 are provided at equal intervals along the circumferential direction of the support portion 88. However, the number and arrangement of the fins 80 are arbitrary.

[0037] The fins 80 are capable of scooping up oil when the carrier 342 rotates (and when the fins 80 rotate as a result). Specifically, the fins 80 can extend below the level of oil that accumulates in the lower part of the transmission mechanism housing chamber S2 of the case 2 due to its own weight, and are capable of scooping up oil when the fins 80 rotate. The oil that accumulates in the lower part of the transmission mechanism housing chamber S2 of the case 2 may be oil used for cooling the rotating electric machine 1 or for various lubrication purposes. The oil scooped up by the fins 80 may be used to lubricate the planetary gear mechanism 34. In addition, the oil scooped up by the fins 80 may be captured by a catch tank (not shown) provided in the case 2 and used for cooling the rotating electric machine 1 or for various lubrication purposes via the catch tank (not shown).

[0038] In this embodiment, the fin 80 is formed such that the force it receives from the oil when scooping up the oil has an axial component A. Specifically, the fin 80 has a surface (hereinafter also referred to as the "inclined surface 82") that is inclined with respect to the axial first side A1 when viewed in a direction perpendicular to the first axis C1, which is the central axis of the planetary gear mechanism 34. The inclined surface 82 is a flat surface, but it may have irregularities or curves. The inclined surface 82 functions when scooping up oil. In this embodiment, because the fin 80 has an inclined surface 82, the force F0 it receives from the oil when scooping up the oil has an axial component A F2, as schematically shown in Figure 5. In Figure 5, it is schematically shown that the force F0 has a component F1 perpendicular to the axial direction A and a component F2 in the axial direction A. If the inclination angle of the inclined surface 82 with respect to a plane containing the axial direction is θ, then the component F2 can be expressed as F0 × sinθ.

[0039] By the way, in this embodiment, as described above, the helical teeth of the first pinion gear 3431 and the second pinion gear 3432 are formed such that the thrust loads generated during rotation cancel each other out. However, as described above in the "Problems to be Solved by the Invention" section, it is difficult to make the thrust loads generated by the first pinion gear 3431 and the second pinion gear 3432 strictly cancel each other out due to manufacturing tolerances, assembly tolerances, etc. Alternatively, the thrust load received by the first pinion gear 3431 may be designed to be slightly larger than the thrust load received by the second pinion gear 3432, in which case, with the design configuration, the thrust loads will not strictly cancel each other out. In this way, if the resultant force of the thrust load received by the first pinion gear 3431 and the thrust load received by the second pinion gear 3432 is significantly greater than 0, the resultant force will attempt to displace the first pinion gear 3431 and the second pinion gear 3432 (and consequently the entire carrier 342) in that direction. If the magnitude of the resultant force exceeds the magnitude of the reaction force such as friction, the carrier 342 will be displaced in the direction of the resultant force and will come into axial contact with a surrounding member located at the destination of the displacement in the direction of the resultant force, thereby receiving a force from the surrounding member and reaching a state of equilibrium.

[0040] In the following, a configuration in which there is a difference between the thrust load received by the first pinion gear 3431 and the thrust load received by the second pinion gear 3432 will also be referred to as a "configuration with a thrust load difference." In such a configuration with a thrust load difference, as described above in the "Problems to be Solved by the Invention" section, the direction of the resultant force of the two thrust loads reverses during vehicle acceleration and deceleration (and similarly during powering and regeneration). For example, in Figure 5, the thrust load received by the first pinion gear 3431 and the thrust load received by the second pinion gear 3432 are shown as F10 and F20, respectively, during vehicle acceleration and deceleration. In this case, if the magnitude of F10 > the magnitude of F20, the direction of the resultant force changes during vehicle acceleration and deceleration (and similarly during powering and regeneration).

[0041] Changes in the direction of the resultant thrust load due to such changes in the vehicle's state can cause changes in the axial position of the carrier 342 (axial position relative to case 2). When the axial position of the carrier 342 changes, it may cause repeated separation and contact with surrounding members (e.g., resin parts) that are in axial contact with the carrier 342, potentially damaging them.

[0042] In this respect, the comparative example shown in Figure 6 cannot reduce or eliminate these problems. Specifically, the comparative example shown in Figure 6 differs in that the fin 80 in this embodiment is replaced with fin 80'. Fin 80' differs from fin 80 in this embodiment in that it does not have an inclined surface 82. That is, instead of an inclined surface 82, fin 80' has a surface 82' consisting of a plane including the first axis C1. In this case, as schematically shown in Figure 6, the force F0 that fin 80' receives from the oil when scooping up the oil substantially does not have an axial component A.

[0043] In contrast, as described above, the fin 80 in this embodiment has an axial A component F2 in the force F0 it receives from the oil when scooping up the oil. Since the fin 80 in this embodiment can generate such an axial A component F2, it can reduce or eliminate the inconveniences that occur in the configuration having the thrust load difference described above. Specifically, even if the component of the thrust load difference described above has a different direction from the axial A component F2, if the component of the thrust load difference described above is smaller than the axial A component F2, the axial A component F2 prevails, and the position of the carrier 342 can be fixed on the side toward which the axial A component F2 is directed. Note that if the component of the thrust load difference described above has the same direction as the axial A component F2, the position of the carrier 342 can be fixed on the side toward which the axial A component F2 is directed, regardless of their relative magnitudes.

[0044] In this way, according to this embodiment, by providing a fin 80 having an inclined surface 82, it is possible to stabilize the axial position of the carrier 342 in the planetary gear mechanism 34.

[0045] Incidentally, in this embodiment, as described above, the thrust load received by the first pinion gear 3431 may be designed to be slightly larger than the thrust load received by the second pinion gear 3432. In this case, the fins 80 are preferably formed such that the direction of the axial component F2 in the axial direction A coincides with the direction of the thrust load received by the first pinion gear 3431. In this case, even when the axial component F2 in the axial direction A due to the fins 80 is relatively small (for example, when the rotational speed is low), the position of the carrier 342 can be kept on the side toward which the thrust load received by the first pinion gear 3431 is directed.

[0046] In this embodiment, reversing the inclination direction of the inclined surface 82 of the fin 80 also reverses the direction of the axial component F2 of the force A exerted by the fin 80. Therefore, the inclination direction of the inclined surface 82 of the fin 80 may be set such that the axial component F2 of the force A exerted by the fin 80 in the rotational direction corresponding to the forward movement of the vehicle is directed to the same side as the thrust load exerted by the first pinion gear 3431.

[0047] In this embodiment, the fin 80 has portions that form inclined surfaces 82 on both sides in the circumferential direction of the flange portion 84 that extends over a portion of the first axis C1, but the portion that forms the inclined surface 82 may be on only one side in the circumferential direction of the flange portion 84. Also, the inclined surface 82 is formed over the entire axial length of the flange portion 84, but it may be formed over only a portion of the entire axial length of the flange portion 84. In this case, a surface like surface 82' in the comparative example (a surface consisting of a plane including the first axis C1) may be formed over the other portion of the entire axial length of the flange portion 84. That is, the inclined surface 82 may be formed in combination with a surface consisting of a plane including the first axis C1.

[0048] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above. [Explanation of symbols]

[0049] 2...Case, 34...Planetary gear mechanism (component of a planetary gear system), 341...Sun gear, 3431...First pinion gear, 3432...Second pinion gear, 342...Carrier, 80...Fin (component of a planetary gear system), 82...Inclined surface (inclined surface)

Claims

1. A planetary gear system that can be placed in a case where oil accumulates, A planetary gear mechanism comprising a sun gear, carrier, and ring gear, The carrier is equipped with fins that are attached to the carrier and rotate together with the carrier, and that are capable of scooping up oil when rotating, The carrier rotatably supports a first pinion gear and a second pinion gear that are aligned in the axial direction and have different diameters. The first pinion gear and the second pinion gear have helical teeth that generate thrust loads in directions that cancel each other out during rotation. A planetary gear device in which the fins are formed such that the force they receive from the oil when scooping up the oil has an axial component to the planetary gear mechanism.

2. The planetary gear apparatus according to claim 1, wherein the fin has a surface that is inclined with respect to the axial direction of the planetary gear mechanism when viewed in a direction perpendicular to the central axis of the planetary gear mechanism.

3. The first pinion gear has a larger thrust load than the second pinion gear. The planetary gear apparatus according to claim 1 or 2, wherein the fins are formed such that the force generated when the vehicle moves forward has an axial component of the planetary gear mechanism that is on the side from the first pinion gear toward the second pinion gear or the reverse side.

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