Transmission

Abstract

To provide a transmission equipped with a parking lock mechanism. [Solution] The transmission comprises a planetary gear mechanism, a case housing the planetary gear mechanism, a connecting component supported so as to be displaceable relative to the case, and a moving mechanism for moving the connecting component between first and third positions. One of the sun gear, ring gear, and carrier is an input rotating body, another is an output rotating body, and the remaining one is an intermediate rotating body. The case is provided with a first engaging portion that can engage with the connecting component. One of the input rotating body and the output rotating body is provided with a second engaging portion that can engage with the connecting component. The intermediate rotating body is provided with a third engaging portion that can engage with the connecting component. In the first position, the connecting component engages the first engaging portion and the third engaging portion. In the second position, the connecting component engages the second engaging portion and the third engaging portion. In the third position, the connecting component engages the first engaging portion, the second engaging portion and the third engaging portion with each other.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a transmission device.

Background Art

[0002] Patent Document 1 discloses content in which a parking lock mechanism is realized by setting a transmission device in an interlock state in a transmission device using a planetary gear mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the transmission device of Patent Document 1, in order to set it in an interlock state, an engagement mechanism for controlling each engagement element is required. An increase in cost due to an increase in the number of parts and an increase in weight become problems.

Means for Solving the Problems

[0005] The transmission disclosed herein is positioned between an input shaft and an output shaft. The transmission comprises a planetary gear mechanism having a sun gear, a ring gear, a carrier, and a pinion gear; a case housing the planetary gear mechanism; a coupling component supported so as to be displaceable relative to the case; and a moving mechanism configured to move the coupling component between a first position, a second position, and a third position. One of the sun gear, the ring gear, and the carrier is an input-side rotor connected to the input shaft. Another of the sun gear, the ring gear, and the carrier is an output-side rotor connected to the output shaft. The remaining one of the sun gear, the ring gear, and the carrier is an intermediate rotor. The case is provided with a first engagement portion that can engage and disengage with the coupling component. One of the input-side rotor and the output-side rotor is provided with a second engagement portion that can engage and disengage with the coupling component. The intermediate rotor is provided with a third engagement portion that can engage and disengage with the coupling component. When the connecting part is in the first position, the connecting part engages the first engaging portion and the third engaging portion with each other. When the connecting part is in the second position, the connecting part engages the second engaging portion and the third engaging portion with each other. When the connecting part is in the third position, the connecting part engages the first engaging portion, the second engaging portion and the third engaging portion with each other.

[0006] In the above configuration, when the connecting component is in the first position, the input and output rotating bodies are rotatable. Therefore, the rotation of the input shaft is converted by the planetary gear mechanism before being output to the output shaft. When the connecting component is in the second position, the input, intermediate, and output rotating bodies can rotate as a single unit. Therefore, the rotation of the input shaft is output to the output shaft without the rotation of the planetary gear mechanism being converted. When the connecting component is in the third position, relative rotation with respect to the case is prohibited for either the input or output rotating body, and for the intermediate rotating body. Since the rotation of two of the three rotating bodies of the planetary gear mechanism can be restricted, the rotation of the planetary gear mechanism can be mechanically locked. Because an interlock state can be achieved using the connecting component for realizing the speed change mechanism, there is no need to separately provide a new engagement mechanism. It is possible to incorporate a parking lock mechanism into the transmission while suppressing cost increases due to an increase in the number of parts and an increase in weight. [Brief explanation of the drawing]

[0007] [Figure 1] This is a skeleton diagram showing the schematic configuration of the drive unit 1. [Figure 2] This diagram schematically shows the engagement state. [Figure 3] This diagram schematically shows a first modified example of the engaged state. [Figure 4] This diagram schematically shows a second modified example of the engaged state. [Figure 5] This diagram schematically shows the engagement state in Example 2. [Figure 6] This figure schematically shows a modified example of the engagement state in Example 2. [Modes for carrying out the invention]

[0008] One of the sun gear and the carrier may be an input-side rotating body. The other of the sun gear and the carrier may be an output-side rotating body. The ring gear may be an intermediate rotating body.

[0009] According to the above configuration, when the sun gear is the input rotating body and the carrier is the output rotating body, a reduction mechanism can be realized when the connecting component is in the first position. Also, when the carrier is the input rotating body and the sun gear is the output rotating body, a speed-increasing mechanism can be realized when the connecting component is in the first position.

[0010] The second engaging portion is located on the carrier and may be coaxial with the ring gear. The third engaging portion may be located on the outer circumference of the ring gear. The connecting component may include a sleeve that is slidably positioned in the direction of the rotation axis of the planetary gear mechanism. The sleeve may be configured to engage with each of the first engaging portion, the second engaging portion, and the third engaging portion.

[0011] According to the above configuration, the operating state of the planetary gear mechanism can be switched by the sleeve.

[0012] The first engagement portion may be located coaxially with the ring gear. The sleeve may have an inner spline formed on its inner circumference. When the sleeve is in the first position, the inner spline may engage with the first and third engagement portions but not with the second engagement portion. When the sleeve is in the second position, the inner spline may engage with the second and third engagement portions but not with the first engagement portion. When the sleeve is in the third position, the inner spline may engage with the first, second, and third engagement portions.

[0013] The first engagement portion may be positioned radially outward of the ring gear. The sleeve may include an inner spline formed on the inner circumference of the sleeve and an outer spline formed on the outer circumference of the sleeve. When the sleeve is in the first position, the inner spline may engage with the third engagement portion, the outer spline may engage with the first engagement portion, and the sleeve may not engage with the second engagement portion. When the sleeve is in the second position, the inner spline may engage with the second and third engagement portions, and the sleeve may not engage with the first engagement portion. When the sleeve is in the third position, the inner spline may engage with the second and third engagement portions, and the outer spline may engage with the first engagement portion. [Examples]

[0014] (Configuration of drive unit 1) Figure 1 is a skeleton diagram illustrating the structure of the drive unit 1 of an electric vehicle. The drive unit 1 is a device that drives a pair of left and right wheels (not shown) of the vehicle. The drive unit 1 may be an integrated device in which the motor, gear unit, and power conversion unit for controlling the motor are housed in the same casing. In Figure 1, the axial direction of the first shaft 61, second shaft 62, ring gear 32, third shaft 63, first output shaft 64, and second output shaft 65 is defined as the x-direction. The case 10 is shown in a cross-sectional view, and the components of the case 10 are hatched. The same applies to subsequent figures.

[0015] The drive unit 1 is controlled by the control unit 2. The control unit 2 includes a CPU, RAM, ROM, input / output interface, etc. The control unit 2 is connected to the motor 20, actuator 41, etc. by signal lines (not shown).

[0016] The drive unit 1 mainly comprises a case 10, a motor 20, a planetary gear mechanism 30, a transmission mechanism 40, an oil pump 50, a first shaft 61, a second shaft 62, a third shaft 63, a first output shaft 64, a second output shaft 65, and a differential gear 70.

[0017] The case 10 has a structure in which the motor cover 11, the center case 12, the intermediate case 13, and the gear cover 14 are arranged side by side in the x direction. Each of these cases may be a casting. By fastening these four members, the case 10 is formed. The case 10 includes a first chamber R1, a second chamber R2, and a third chamber R3. The first chamber, the second chamber, and the third chamber are arranged in this order along the axial direction (i.e., the x direction) of the first shaft 61. The case 10 includes a first wall W1, a second wall W2, and a third wall W3. The first wall W1 separates the first chamber R1 and the second chamber R2. The second wall W2 separates the second chamber R2 and the third chamber R3. The third wall W3 defines the third chamber R3 between itself and the second wall W2.

[0018] The first wall W1 is provided with bearings 81 and 82. The bearing 81 rotatably supports the first shaft 61. The bearing 82 rotatably supports the second shaft 62. The second wall W2 is provided with bearings 83, 84, and 85. The bearing 83 rotatably supports the first shaft 61. The bearing 84 rotatably supports the third shaft 63. The bearing 85 rotatably supports the first output shaft 64. The third wall W3 is provided with bearings 86 and 87. The bearing 86 rotatably supports the third shaft 63. The bearing 87 rotatably supports the second output shaft 65.

[0019] The effects will be described. The first wall W1, the second wall W2, and the third wall W3 are provided with various bearings. As a result, three assemblies, namely, the assembly having the first wall W1, the assembly having the second wall W2, and the assembly having the third wall W3, can be pre-assembled. And in the final assembly process, these three assemblies may be assembled. It becomes possible to simplify the assembly process of the drive device 1.

[0020] In the first chamber R1, the motor 20 and the oil pump 50 are mainly housed. The motor 20 includes a stator 21, a rotor 22, and a motor shaft 23. The stator 21 has a cylindrical shape. Inside the stator 21, the rotor 22 is rotatably arranged. The motor shaft 23 is fixed to the rotor 22.

[0021] In the second chamber R2, the first shaft 61, the second shaft 62, the first gear pair 91, the planetary gear mechanism 30, and a part of the transmission mechanism 40 are mainly housed. The first shaft 61 is coaxially connected to the motor shaft 23. The first shaft and the motor shaft 23 have a hollow structure. The first shaft 61 is supported by bearings 81 and 83. The first shaft 61 is driven by the motor 20.

[0022] The second shaft 62 is arranged parallel to the first shaft 61. The second shaft 62 is supported by bearings 82 and 89. The first shaft 61 and the second shaft 62 are coupled by the first gear pair 91. The driving force of the first shaft 61 is transmitted to the second shaft 62.

[0023] The planetary gear mechanism 30 includes a sun gear 31, a ring gear 32, a pinion gear 33, and a carrier 34. The sun gear 31 is arranged at the +x direction end of the second shaft 62. The sun gear 31 is mechanically connected to the motor shaft 23 via the first gear pair 91 and the first shaft 61. Thus, the planetary gear mechanism 30 has the sun gear 31 as the input and the carrier 34 as the output.

[0024] The -x end of the second shaft 62 is connected to the oil pump 50. This mechanically connects the oil pump 50 to the sun gear 31. The oil pump 50 is responsible for circulating oil within the case 10. The oil pump 50 is a mechanical pump and is driven in conjunction with the rotation of the sun gear 31. This allows the amount of oil circulated to increase in conjunction with the increase in the rotational speed of the sun gear 31. This effectively prevents seizure and wear in the various gears within the case 10.

[0025] Chamber R3 mainly houses the third shaft 63, the second gear pair 92, the differential gear 70, the first output shaft 64, the second output shaft 65, and part of the transmission mechanism 40. The third shaft 63 is arranged coaxially with the second shaft 62. The third shaft 63 is supported by bearings 84 and 86. The -x end of the third shaft 63 is connected to the carrier 34. The driving force output from the planetary gear mechanism 30 is transmitted to the third shaft 63. The third shaft 63 is coupled to the differential gear 70 by the second gear pair 92. The second gear pair 92 is a gear pair consisting of a parallel gear located on the third shaft 63 and a ring gear provided on the differential gear 70.

[0026] The differential gear 70 is a mechanism that distributes the driving force transmitted from the third shaft 63 to a pair of left and right first output shafts 64 and second output shafts 65. The first output shafts 64 and second output shafts 65 are arranged coaxially with each other. The first output shafts 64 and second output shafts 65 are shafts for outputting driving force to a pair of tires (not shown).

[0027] The first output shaft 64 is supported by bearings 85 and 88. The +x end of the first output shaft 64 is connected to the differential gear 70. The -x end of the first output shaft 64 passes through the first shaft 61. This reduces the space required for arranging the first output shaft 64, thereby enabling a smaller overall size for the drive unit 1.

[0028] The second output shaft 65 is supported by a bearing 87. The -x end of the second output shaft 65 is connected to the differential gear 70.

[0029] (Configuration of the transmission mechanism 40) The transmission mechanism 40 mainly comprises an actuator 41, a ball screw 42, a biasing unit 43, a shift fork 44, a sleeve 45, a first ring portion 46, a second ring portion 47, and a ring gear hub 48. The first ring portion 46 is located coaxially with the ring gear 32 and is positioned on the second wall W2. The second ring portion 47 is located coaxially with the ring gear 32 and is positioned on the carrier 34. The ring gear hub 48 is located coaxially with the ring gear 32 and is fixed to the outer circumference of the ring gear 32. The sleeve 45 is slidably positioned in the axial direction (i.e., x-direction) of the ring gear 32.

[0030] In this embodiment, the sun gear 31 corresponds to the input side rotating body connected to the input shaft. The carrier 34 corresponds to the output side rotating body connected to the output shaft. The ring gear 32 corresponds to the intermediate rotating body. Therefore, the first ring portion 46 corresponds to the first engagement portion provided on the case 10. The second ring portion 47 corresponds to the second engagement portion provided on the output side rotating body. The ring gear hub 48 corresponds to the third engagement portion provided on the intermediate rotating body.

[0031] Figure 2 schematically shows the engagement state of the sleeve 45, the first ring portion 46, the second ring portion 47, and the ring gear hub 48. Splines 46s, 47s, and 48s are formed on the outer circumference of the first ring portion 46, the second ring portion 47, and the ring gear hub 48, respectively. An inner circumference spline 45s is formed on the inner circumference of the sleeve 45. The inner circumference spline 45s is configured to engage with the splines 46s, 47s, and 48s of the first ring portion 46, the second ring portion 47, and the ring gear hub 48, respectively. Furthermore, the inner circumference spline 45s has a tooth shape that allows it to engage with two or three of the splines 46s, 47s, and 48s simultaneously.

[0032] Actuator 41 is a rotary actuator. In this embodiment, actuator 41 is a motor. Ball screw 42 is a linear motion mechanism that converts the rotational motion output by actuator 41 into linear motion. The nut 42n of ball screw 42 is connected to shift fork 44 via biasing part 43. The -x end of shift fork 44 is connected to sleeve 45. Shift fork 44 is a component that transmits the linear motion output by ball screw 42 to sleeve 45. Shift fork 44 is configured to be movable in a first direction D1 and a second direction D2 in the axial direction of ring gear 32. The first direction D1 is the direction away from ring gear 32 (i.e., the +x direction). The second direction D2 is the direction towards ring gear 32 (i.e., the -x direction).

[0033] The biasing unit 43 is equipped with a spring (not shown) and applies an axial biasing force of the ring gear to the shift fork 44. When the shift fork moves in the first direction D1, the biasing unit 43 applies a biasing force in the first direction D1 to the shift fork 44. Furthermore, when the shift fork moves in the second direction D2, the biasing unit 43 applies a biasing force in the second direction D2 to the shift fork 44. The specific structure for realizing the function of the biasing unit 43 is well known, so a detailed explanation is omitted.

[0034] (Operation of the gear shift mechanism 40) The speed control mechanism 40 is a mechanism that can switch the operating mode of the planetary gear mechanism 30 between a first mode, a second mode, and a parking mode. In the first mode, the rotation of the motor 20 is reduced before being transmitted to the output shaft. In the second mode, the rotation of the motor 20 is transmitted to the output shaft without reduction. In the parking mode, the rotation of the planetary gear mechanism 30 is mechanically locked. Switching between operating modes is performed by moving the sleeve 45 between the first position P1, the second position P2, and the third position P3. This will be explained below.

[0035] The first mode will be explained using Figure 2(A). In the first mode, the sleeve 45 is in the first position P1. In the first position P1, the sleeve 45 is engaged with the ring gear hub 48 and the first ring portion 46, but not with the second ring portion 47. The ring gear 32 is coupled to the case 10 in a way that prevents relative rotation, and the ring gear 32 is discoupled from the carrier 34. In other words, in the first mode, relative rotation of the ring gear 32 with respect to the case 10 is prohibited, while relative rotation of the ring gear 32 with respect to the carrier 34 is permitted. Therefore, the carrier 34 is rotatable around the central axis of the sun gear 31. Thus, the rotation of the first shaft 61 is transmitted to the carrier 34 via the sun gear 31 and the pinion gear 33 (see the transmission path T1 shown by the dotted arrow in Figure 1). As a result, the planetary gear mechanism 30 functions as a reduction gear.

[0036] The second mode will be explained using Figure 2(B). In the second mode, the sleeve 45 is in the second position P2. In the second position P2, the sleeve 45 is engaged with the ring gear hub 48 and the second ring portion 47, but not with the first ring portion 46. The ring gear 32 is connected to the carrier 34 in a way that prevents relative rotation, and the ring gear 32 is disconnected from the case 10. In other words, in the second mode, relative rotation of the ring gear 32 with respect to the carrier 34 is prohibited, while relative rotation of the ring gear 32 with respect to the case 10 is permitted. Therefore, the carrier 34 and the ring gear 32 rotate together with the sun gear 31. Thus, the rotation of the first shaft 61 is transmitted to the carrier 34 via the sun gear 31, pinion gear 33, ring gear 32, ring gear hub 48, sleeve 45, and second ring portion 47 (see Figure 1, transmission path T2 shown by the dotted arrow). As a result, the planetary gear mechanism 30 does not function as a reduction gear.

[0037] The parking mode is explained using Figure 2(C). In parking mode, the sleeve 45 is in the third position P3. In the third position P3, the sleeve 45 engages the first ring portion 46, the second ring portion 47, and the ring gear hub 48 with each other. The carrier 34, which is the output rotating body, and the ring gear hub 48, which is the intermediate rotating body, are prohibited from rotating relative to the case 10. Since the rotation of two of the three rotating bodies of the planetary gear mechanism 30 can be restricted, the rotation of the planetary gear mechanism 30 can be mechanically locked. As a result, the planetary gear mechanism 30 functions as a parking mechanism.

[0038] (effect) In the technology described herein, by appropriately arranging the shape of the inner spline 45s of the sleeve 45, two driving modes and a parking function can be incorporated into a single transmission mechanism 40. That is, since the interlock state can be achieved using the sleeve 45 that realizes the transmission mechanism 40, there is no need to separately provide a new engagement mechanism to realize the parking function. This makes it possible to incorporate a parking function into the transmission mechanism 40 while suppressing cost increases due to an increase in the number of parts and an increase in weight.

[0039] (Modified version of Example 1) The tooth shape of the inner spline 45s of the sleeve 45, and the positions of the first position P1, second position P2, and third position P3 may vary. Figure 3 shows a first modified example. In the example in Figure 3, the sleeve 45 has a tooth shape in which the inner spline 45s is arranged along the entire axial direction (x direction). Even with this tooth shape, it is possible to switch between the first mode in Figure 3(A), the second mode in Figure 3(B), and the parking mode in Figure 3(C).

[0040] Figure 4 shows a second modified example. In the example in Figure 4, the sleeve 45 has a tooth shape that is the same as the sleeve 45 in Figure 2 but reversed left and right with respect to the axial direction. With this tooth shape as well, it is possible to switch between the first mode in Figure 4(A), the second mode in Figure 4(B), and the parking mode in Figure 4(C). [Examples]

[0041] In Example 2, the configuration of the sleeve 45 and the first ring portion 46 differs from that of Example 1. Below, only the parts that differ from Example 1 will be described.

[0042] Figure 5 schematically shows the engagement state of the sleeve 45, the first ring portion 46, the second ring portion 47, and the ring gear hub 48. Figure 5 is the same drawing as Figure 2. The first ring portion 46 is positioned radially outward (i.e., on the +z direction side) relative to the ring gear 32. The first ring portion 46 is fixed to the case 10. The first ring portion 46 also has a spline 46s positioned opposite the sleeve 45. In addition to the inner spline 45s formed on the inner circumference of the sleeve 45, the sleeve 45 further has an outer spline 45p formed on the outer circumference.

[0043] The first mode will be explained using Figure 5(A). In the first mode, the sleeve 45 is in the first position P1. In the first position P1, the inner spline 45s of the sleeve 45 engages with the spline 48s of the ring gear hub 48, and the outer spline 45p of the sleeve 45 engages with the spline 46s of the first ring portion 46. The sleeve 45 is not engaged with the spline 47s of the second ring portion 47.

[0044] The second mode will be explained using Figure 5(B). In the second mode, the sleeve 45 is in the second position P2. In the second position P2, the inner spline 45s of the sleeve 45 engages with the spline 47s of the second ring portion 47 and the spline 48s of the ring gear hub 48. The sleeve 45 is not engaged with the spline 46s of the first ring portion 46.

[0045] The parking mode will be explained using Figure 5(C). In parking mode, the sleeve 45 is in the third position P3. In the third position P3, the inner spline 45s of the sleeve 45 engages with the spline 47s of the second ring portion 47 and the spline 48s of the ring gear hub 48. In addition, the outer spline 45p of the sleeve 45 engages with the spline 46s of the first ring portion 46.

[0046] (Modified version of Example 2) In Example 2, the tooth shapes of the inner spline 45s and outer spline 45p of the sleeve 45 may vary. A modified example is shown in Figure 6. In the example in Figure 6, the sleeve 45 has a tooth shape in which the inner spline 45s is arranged along the entire axial direction (x direction). Even with this tooth shape, it is possible to switch between the first mode in Figure 6(A), the second mode in Figure 6(B), and the parking mode in Figure 6(C).

[0047] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself.

[0048] (modified version) This specification describes a case where the sun gear 31 is the input rotating body, the carrier 34 is the output rotating body, and the ring gear 32 is the intermediate rotating body, but the specification is not limited to this configuration. For example, when the carrier 34 is the input rotating body, the sun gear 31 is the output rotating body, and the ring gear 32 is the intermediate rotating body, a speed-increasing mechanism can be realized when the sleeve 45 is in the first position P1. Also, for example, when the ring gear 32 is the input rotating body, the carrier 34 is the output rotating body, and the sun gear 31 is the intermediate rotating body, a reduction mechanism can be realized when the sleeve 45 is in the first position P1.

[0049] The drive unit 1 may be configured to include only one of the first output shaft 64 and the second output shaft 65. In this case, the differential gear 70 can be omitted.

[0050] In this specification, a sleeve 45 is described as an example of a connecting component, but the invention is not limited to this form. The connecting component may also be a pin, a ball, or the like.

[0051] The vehicles on which the drive system described herein is installed are not limited to electric vehicles. The drive system described herein can be installed in, for example, hybrid vehicles and plug-in hybrid vehicles. In this case, the drive system described herein may house multiple motors or a planetary gear mechanism within the casing. Furthermore, the drive system described herein is also applicable to vehicles that use electric motors for at least part of their propulsion, such as fuel cell vehicles.

[0052] The gear shifting mechanism 40 is an example of a moving mechanism. The sleeve 45 is an example of a connecting component. [Explanation of symbols]

[0053] 1: Drive unit 10: Case 20: Motor 30: Planetary gear mechanism 31: Sun gear 32: Ring gear 33: Pinion gear 34: Carrier 40: Speed ​​change mechanism 41: Actuator 45: Sleeve 46: First ring section 47: Second ring section 48: Ring gear hub

Claims

1. A transmission device positioned between the input shaft and the output shaft, A planetary gear mechanism having a sun gear, ring gear, carrier, and pinion gear, A case housing the aforementioned planetary gear mechanism, A connecting component supported so as to be displaceable relative to the case, A moving mechanism configured to allow the connecting component to move between a first position, a second position, and a third position, Equipped with, One of the sun gear, the ring gear, and the carrier is an input-side rotating body connected to the input shaft. The sun gear, the ring gear, and the other carrier are output-side rotating bodies connected to the output shaft. The remaining one of the sun gear, the ring gear, and the carrier is an intermediate rotating body. The case is provided with a first engaging portion that can engage with and disengage from the connecting component. One of the input-side rotating body and the output-side rotating body is provided with a second engaging portion that can engage with and disengage from the connecting component. The intermediate rotating body is provided with a third engaging portion that can engage with and disengage from the connecting component. When the connecting component is in the first position, the connecting component engages the first engaging portion and the third engaging portion with each other. When the connecting component is in the second position, the connecting component engages the second engaging portion and the third engaging portion with each other. When the connecting component is in the third position, the connecting component engages the first engaging portion, the second engaging portion, and the third engaging portion with each other. Transmission.

2. One of the sun gear and the carrier is the input side rotating body, The other of the sun gear and the carrier is the output side rotating body. The transmission according to claim 1, wherein the ring gear is the intermediate rotating body.

3. The second engaging portion is located on the carrier and is coaxial with the ring gear. The third engaging portion is located on the outer circumference of the ring gear, The connecting component includes a sleeve that is slidably positioned in the direction of the rotation axis of the planetary gear mechanism. The transmission according to claim 2, wherein the sleeve is configured to be able to engage with each of the first engaging portion, the second engaging portion, and the third engaging portion.

4. The first engaging portion is located coaxially with the ring gear, The sleeve is provided with an inner spline formed on its inner circumference, When the sleeve is in the first position, the inner circumferential spline engages with the first engagement portion and the third engagement portion, but does not engage with the second engagement portion. When the sleeve is in the second position, the inner circumferential spline engages with the second and third engaging portions but not with the first engaging portion. The transmission according to claim 3, wherein when the sleeve is in the third position, the inner circumferential spline engages with the first engaging portion, the second engaging portion, and the third engaging portion.

5. The first engaging portion is positioned radially outward of the ring gear, The sleeve comprises an inner spline formed on the inner circumference of the sleeve and an outer spline formed on the outer circumference of the sleeve. When the sleeve is in the first position, the inner spline engages with the third engagement portion, the outer spline engages with the first engagement portion, and the sleeve is not engaged with the second engagement portion. When the sleeve is in the second position, the inner circumferential spline engages with the second engagement portion and the third engagement portion, and the sleeve is not engaged with the first engagement portion. The transmission according to claim 3, wherein when the sleeve is in the third position, the inner spline engages with the second and third engaging portions, and the outer spline engages with the first engaging portion.

Images