Power transmission device

Abstract

To provide a power transmission device capable of improving the degree of freedom of design.SOLUTION: In the power transmission device 1 including a first rotating shaft 13 rotatably arranged and provided with a first gear 33, and a second rotating shaft 15 rotatably arranged and provided with a second gear 35 meshing with the first gear 33 and capable of transmitting power to the first rotating shaft 13, the second gear 35 is arranged on the second rotating shaft 15 so as to be relatively rotatable to the second rotating shaft 15. The second rotary shaft 15 is provided with a hub 39 capable of transmitting power to the second gear 35, and a park lock gear 21 engageable with a lock member for preventing rotation of the second rotary shaft 15, and the park lock gear 21, the hub 39, and the second gear 35 are arranged in the axial direction of the second rotary shaft 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power transmission device. [Background technology]

[0002] A conventional power transmission device is known that includes a third input member as a first rotating shaft that is rotatably arranged and has an eighth gear as a first gear provided thereon, and a second countershaft as a second rotating shaft that is rotatably arranged and has a ninth gear as a second gear that meshes with the eighth gear and that can transmit power between the third input member and the third input member (see Patent Document 1).

[0003] In this power transmission device, the ninth gear is disposed on the second countershaft so as to be rotatable relative to the second countershaft. The second countershaft is provided with a fourth engagement portion serving as a hub capable of transmitting power to the ninth gear, and a parking lock gear engageable with a lock member that prevents rotation of the second countershaft. In this power transmission device, power transmission between the third input member and the second countershaft can be interrupted by connecting and disconnecting power transmission between the ninth gear and the fourth engagement portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 039134 Summary of the Invention [Problem to be solved by the invention]

[0005] In a power transmission device such as that disclosed in Patent Document 1, the second gear is rotatable relative to the second rotating shaft. Therefore, the second gear needs to be formed separately from the second rotating shaft. The hub and the parking lock gear are rotatable integrally with the second rotating shaft. Therefore, the hub and the parking lock gear need to be formed as a single member continuous with the second rotating shaft, or formed separately from the second rotating shaft and connected to be rotatable integrally.

[0006] For example, if the hub and the park lock gear are formed as a single member that is continuous with the second rotating shaft, the number of parts and the number of assembly steps can be reduced, improving ease of assembly. If the hub and the park lock gear are formed as separate members from the second rotating shaft, the hub and the park lock gear can be designed independently of the second rotating shaft.

[0007] In the power transmission device of Patent Document 1, the parking lock gear, the second gear, and the hub are arranged in the axial direction of the second rotating shaft. In this arrangement, the parking lock gear can be formed as a single member continuous with the second rotating shaft, or formed as a separate member from the second rotating shaft and connected to it so as to rotate integrally with it. However, if the hub is formed as a single member continuous with the second rotating shaft, the second gear cannot be disposed on the second rotating shaft. For this reason, the hub can only be designed so as to be formed as a separate member from the second rotating shaft and connected to it so as to rotate integrally with it, which reduces the degree of freedom in design.

[0008] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a power transmission device that allows for increased freedom in design. [Means for solving the problem]

[0009] The power transmission device of this embodiment comprises a first rotating shaft that is rotatably arranged and has a first gear provided thereon, and a second rotating shaft that is rotatably arranged and has a second gear that meshes with the first gear and is capable of transmitting power between the first rotating shaft and the second gear, the second gear is arranged on the second rotating shaft so as to be rotatable relative to the second rotating shaft, the second rotating shaft is provided with a hub that can transmit power to the second gear and a parking lock gear that can engage with a lock member that prevents rotation of the second rotating shaft, and the parking lock gear, the hub, and the second gear are arranged in the axial direction of the second rotating shaft. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a power transmission device that allows for improved freedom of design. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a power transmission device according to an embodiment of the present invention. [Figure 2] 5 is a cross-sectional view showing another example of the arrangement of the second gear, the hub, and the park lock gear of the power transmission device according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The power transmission device according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0013] 1, a power transmission device 1 according to this embodiment is disposed, for example, in a power transmission path of a vehicle, between an electric motor (not shown) as a drive source and left and right drive wheels. The drive force of the electric motor is transmitted to a differential mechanism 5 via a transmission mechanism 3, and the drive force is distributed to the left and right drive wheels via a pair of output shafts (not shown).

[0014] As shown in FIG. 1, the power transmission device 1 includes an electric motor, a transmission mechanism 3, and a differential mechanism 5.

[0015] The electric motor includes a stator (not shown) and a rotor 7. The stator is disposed outside the casing 9 on one side of the transmission mechanism 3 in the direction of the rotation axis. The stator is electrically connected to a controller (not shown) that controls the energization and to a power source that supplies electric power. The rotor 7 is disposed rotatably via bearings 11 (only one of which is shown) on the outer periphery on both axial sides. The rotor 7 is rotated by energizing the stator. One end of the rotor 7 is disposed inside the casing 9, and power can be transmitted between it and the transmission mechanism 3.

[0016] The transmission mechanism 3 is disposed on a power transmission path between the electric motor and the differential mechanism 5. The transmission mechanism 3 includes a first rotating shaft 13, a second rotating shaft 15, a transmission gear set 17, a clutch unit 19, a park lock gear 21, and a third gear 23.

[0017] The first rotating shaft 13 is rotatably supported on the casing 9 via bearings 25 and 27 on both axial ends thereof. The rotation axis of the first rotating shaft 13 is arranged concentrically with the rotation axis of the rotor 7 of the electric motor. One end of the first rotating shaft 13 is connected to the rotor 7 of the electric motor via a connecting portion so as to be rotatable integrally therewith. The first rotating shaft 13 is rotated by the rotation of the rotor 7 of the electric motor.

[0018] The second rotating shaft 15 is rotatably supported on the outer periphery on both axial sides by the casing 9 via bearings 29 and 31. The second rotating shaft 15 is disposed such that its rotation axis is parallel to the rotation axis of the first rotating shaft 13.

[0019] The transmission gear set 17 is provided to be able to transmit power between the first rotating shaft 13 and the second rotating shaft 15, and has a first gear 33 and a second gear 35. The first gear 33 is formed on the outer periphery of the other end side of the first rotating shaft 13 as a single member that is continuous with the first rotating shaft 13. The second gear 35 is formed with a larger diameter than the first gear 33 and meshes with the first gear 33. The second gear 35 is formed separately from the second rotating shaft 15 and is disposed on the outer periphery of the second rotating shaft 15 via a bearing 37 so as to be rotatable relative to the second rotating shaft 15. The transmission gear set 17 transmits the driving force from the electric motor from the first rotating shaft 13 to the second rotating shaft 15 after reducing the speed.

[0020] The clutch unit 19 includes an intermittent portion formed between the second gear 35 and the hub 39, and a sleeve 41 that operates the intermittent portion. The hub 39 is disposed adjacent to the second gear 35 in the axial direction of the second rotating shaft 15. The hub 39 is formed in an annular shape from a single member that is continuous with the second rotating shaft 15. By forming the hub 39 from a single member that is continuous with the second rotating shaft 15, the number of parts and the number of assembly steps can be reduced, and assembly can be made easier.

[0021] The intermittent portion is made up of a plurality of concave and convex engaging portions provided in the circumferential direction of second gear 35 and a connecting portion provided in a spline pattern on the outer periphery of hub 39. Sleeve 41 is formed in an annular shape and is connected to the connecting portion of hub 39 so as to be movable in the axial direction and to rotate integrally with hub 39. A fork (not shown) of an actuator (not shown) engages with the outer periphery of sleeve 41, and sleeve 41 is operated to move in the axial direction.

[0022] When the sleeve 41 of the clutch portion 19 moves axially toward the second gear 35, the sleeve 41 engages with the engaging portion of the second gear 35, and the disconnecting portion is brought into an engaged state. When the disconnecting portion is engaged, the second gear 35 and the second rotating shaft 15 can rotate integrally, and the driving force from the electric motor is transmitted from the first rotating shaft 13 to the second rotating shaft 15 via the transmission gear set 17.

[0023] When the sleeve 41 moves axially toward the hub 39, the engagement between the sleeve 41 and the engaging portion of the second gear 35 is released, and the disconnecting portion of the clutch portion 19 is put into a disconnected state. When the connection of the disconnecting portion is released, the second gear 35 and the second rotating shaft 15 become rotatable relative to each other, and power transmission between the electric motor and the second rotating shaft 15 is interrupted.

[0024] The park lock gear 21 is disposed on the opposite side of the second gear 35 in the axial direction of the second rotating shaft 15, across the hub 39. The park lock gear 21 has a larger diameter than the hub 39 and is formed in an annular shape on the outer periphery of the second rotating shaft 15 from a single member that is continuous with the second rotating shaft 15. By forming the park lock gear 21 from a single member that is continuous with the second rotating shaft 15, the number of parts and assembly steps can be reduced, improving assembly efficiency. The park lock gear 21 is engageable with a lock member (not shown) of a parking lock mechanism (not shown). When engaged with the lock member, the park lock gear 21 prevents rotation of the second rotating shaft 15 and prevents the vehicle from moving while parked. Note that the park lock gear 21 does not necessarily have to have a larger diameter than the hub 39; it may be formed separately from the hub 39 and joined integrally therewith.

[0025] The third gear 23 is disposed at the end of the second rotating shaft 15 opposite to the second gear 35 in the axial direction. The third gear 23 is formed on the outer periphery of the second rotating shaft 15 by a single member that is continuous with the second rotating shaft 15. The third gear 23 outputs the driving force of the electric motor transmitted to the second rotating shaft 15 to the differential mechanism 5.

[0026] The differential mechanism 5 is disposed on a power transmission path between the electric motor (transmission mechanism 3) and the left and right drive wheels. The differential mechanism 5 includes a differential case 43, a pinion shaft 45, a differential gear 47, and a pair of output gears 49, 51.

[0027] The differential case 43 is rotatably supported on the casing 9 via a pair of bearings 57, 59 at the outer peripheries of bosses 53, 55 formed on both axial sides. The rotation axis of the differential case 43 functions as a third rotation axis that is arranged parallel to the rotation axes of the first rotation shaft 13 and the second rotation shaft 15. The differential case 43 is formed with a flange portion 63 to which a fourth gear 61 made of a ring gear is fixed.

[0028] The fourth gear 61 meshes with the third gear 23 of the second rotating shaft 15 in the transmission mechanism 3. The fourth gear 61 receives the driving force of the electric motor and rotates the differential case 43. The third gear 23, which meshes with the fourth gear 61 and outputs the driving force, and the second gear 35, to which the driving force is input, are arranged spaced apart on both sides of the differential mechanism 5 in the rotational axis direction of the second rotating shaft 15. Therefore, the input and output parts of the driving force are arranged spaced apart on both sides of the axial direction of the second rotating shaft 15, thereby stabilizing the rotational balance of the second rotating shaft 15. The differential case 43 houses a pinion shaft 45, a differential gear 47, and a pair of output gears 49, 51.

[0029] In this embodiment, the pinion shaft 45 is a single long pinion shaft, but it may also be a combination of one long pinion shaft and two short pinion shafts. In the case of a long pinion shaft, both ends are engaged with holes formed in the differential case 43 to prevent it from coming off, and it is rotated and driven integrally with the differential case 43. In the case of a short pinion shaft, one end is engaged with a hole formed in the middle of the long pinion shaft, and the other end is engaged with a hole formed in the differential case 43 to prevent it from coming off, and it is rotated and driven integrally with the differential case 43. Differential gears 47 are supported on the outer end sides of the pinion shafts 45, respectively.

[0030] One differential gear 47 is disposed on each end of the pinion shaft 45. The multiple differential gears 47 are supported on the end of the pinion shaft 45 and revolve with the rotation of the differential case 43. The differential gears 47 are rotatably supported on the pinion shaft 45 so as to be rotationally driven when a differential rotation occurs between the pair of meshed output gears 49, 51. The differential gears 47 transmit the driving force input to the differential case 43 to the pair of output gears 49, 51.

[0031] The pair of output gears 49, 51 are housed in the differential case 43 so as to be rotatable relative to one another. The pair of output gears 49, 51 are each meshed with the differential gear 47. Spline-shaped output portions 65, 67 that output the driving force transmitted to the pair of output gears 49, 51 are provided on the inner circumferential sides of the pair of output gears 49, 51. A pair of output shafts (not shown) that are connected to left and right drive wheels so as to be rotatable together are connected to the output portions 65, 67 so as to be rotatable together.

[0032] In the differential mechanism 5, the driving force from the electric motor is input to a differential case 43. The driving force input to the differential case 43 is transmitted to a pair of output gears 49, 51 via a differential gear 47. The driving force transmitted to the pair of output gears 49, 51 is distributed and output to the left and right drive wheels.

[0033] In such a power transmission device 1, the second gear 35 is rotatable relative to the second rotating shaft 15. Therefore, the second gear 35 needs to be formed separately from the second rotating shaft 15. The hub 39 and the parking lock gear 21 are rotatable integrally with the second rotating shaft 15. Therefore, the hub 39 and the parking lock gear 21 need to be formed as a single member that is continuous with the second rotating shaft 15, or formed separately from the second rotating shaft 15 and connected to be rotatable integrally.

[0034] If the hub 39 and the parking lock gear 21 are formed as a single member that is continuous with the second rotating shaft 15, the number of parts and the number of assembly steps can be reduced, and assembly can be improved. If the hub 39 and the parking lock gear 21 are formed separately from the second rotating shaft 15 and connected to each other so as to be rotatable integrally, the hub 39 and the parking lock gear 21 can be designed independently of the second rotating shaft 15.

[0035] Therefore, the second gear 35, hub 39, and parking lock gear 21 are arranged in the axial direction of the second rotating shaft 15 in the order of parking lock gear 21, hub 39, and second gear 35 toward the right-hand shaft end of the second rotating shaft 15. In this arrangement, even if the hub 39 and parking lock gear 21 are formed from a single member continuous with the second rotating shaft 15, the second gear 35 can be arranged on the second rotating shaft 15. Therefore, it is possible to select whether the hub 39 and the parking lock gear 21 are formed from a single member continuous with the second rotating shaft 15 or as separate members, thereby improving the degree of freedom in design.

[0036] Here, the second gear 35, the hub 39, and the parking lock gear 21 may be arranged as shown in Fig. 2. In this arrangement, the parking lock gear 21, the hub 39, and the second gear 35 are arranged in the axial direction of the second rotating shaft 15 toward the left end of the second rotating shaft 15. Note that a third gear 23 formed separately from the second rotating shaft 15 and connected to the outer periphery of the second rotating shaft 15 so as to be rotatable integrally with the second rotating shaft 15 is provided on the left end of the second rotating shaft 15. Even with this arrangement, it is possible to select whether the hub 39 and the parking lock gear 21 are formed as a single member continuous with the second rotating shaft 15 or as separate members, thereby improving the degree of freedom in design.

[0037] Such a power transmission device 1 includes a first rotating shaft 13 that is rotatably arranged and has a first gear 33 provided thereon, and a second rotating shaft 15 that is rotatably arranged and has a second gear 35 that meshes with the first gear 33 and is capable of transmitting power between the first rotating shaft 13 and the second rotating shaft 15. The second gear 35 is arranged on the second rotating shaft 15 so as to be rotatable relative to the second rotating shaft 15. The second rotating shaft 15 is also provided with a hub 39 that can transmit power to the second gear 35, and a parking lock gear 21 that can engage with a lock member that prevents rotation of the second rotating shaft 15. The parking lock gear 21, hub 39, and second gear 35 are arranged in an axial direction of the second rotating shaft 15.

[0038] In this arrangement, the second gear 35 can be disposed on the second rotating shaft 15 even when the hub 39 and the parking lock gear 21 are formed from a single member that is continuous with the second rotating shaft 15. This makes it possible to select whether the hub 39 and the parking lock gear 21 are formed from a single member that is continuous with the second rotating shaft 15 or as separate members, thereby improving the degree of freedom in design.

[0039] Therefore, in such a power transmission device 1, the degree of freedom in design can be improved.

[0040] The hub 39 has a smaller diameter than the park lock gear 21 and is formed of a single member that is continuous with the second rotary shaft 15 .

[0041] Therefore, the second rotating shaft 15 and the hub 39 can be handled as one member, the number of parts and the number of assembly steps can be reduced, and the ease of assembly can be improved.

[0042] Moreover, the park lock gear 21 is formed of a single member that is continuous with the second rotary shaft 15.

[0043] Therefore, the second rotating shaft 15 and the park lock gear 21 can be handled as one member, which reduces the number of parts and the number of assembly steps, thereby improving the ease of assembly.

[0044] The second rotating shaft 15 is provided with a third gear 23 capable of transmitting power to the output side. The third gear 23 meshes with a fourth gear 61 arranged on the third rotating shaft on the output side. The third rotating shaft is a differential case 43 of a differential mechanism 5 that includes a differential gear 47 that distributes power to a pair of output sides and a pair of output gears 49, 51. The second gear 35 and the third gear 23 are arranged spaced apart on either side of the differential mechanism 5 in the direction of the rotating shaft.

[0045] Therefore, the input and output portions of the driving force are arranged at a distance from each other on both axial sides of the second rotating shaft 15, and the rotational balance of the second rotating shaft 15 can be stabilized.

[0046] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

[0047] For example, the hub and the parking lock gear are formed as a single member continuous with the second rotating shaft, but this is not limiting, and the hub and the parking lock gear may be formed as separate members from the second rotating shaft and connected to each other so as to rotate integrally. In addition, either the hub or the parking lock gear may be formed as a single member continuous with the second rotating shaft, and the other may be formed as a separate member from the second rotating shaft and connected to each other so as to rotate integrally. [Explanation of symbols]

[0048] 1 Power transmission device 5 Differential mechanism 13 First rotation axis 15 Second rotation axis 21 Park Lock Gear 23 Third Gear 33 1st Gear 35 2nd Gear 39 Hub 43 Differential case 47 Differential gear 49,51 Output gear 61 4th Gear

Claims

1. a first rotation shaft rotatably disposed and provided with a first gear; a second rotating shaft that is rotatably arranged, has a second gear that meshes with the first gear, and is capable of transmitting power between the second rotating shaft and the first rotating shaft; Equipped with the second gear is disposed on the second rotation shaft so as to be rotatable relative to the second rotation shaft, The second rotating shaft is provided with a hub capable of transmitting power to the second gear and a park lock gear capable of engaging with a lock member that prevents rotation of the second rotating shaft, The power transmission device includes the parking lock gear, the hub, and the second gear arranged in the axial direction of the second rotating shaft.

2. 2. The power transmission device according to claim 1, wherein the hub has a diameter smaller than that of the park lock gear and is formed of a single member that is continuous with the second rotary shaft.

3. 3. The power transmission device according to claim 1, wherein the park lock gear is formed of a single member that is continuous with the second rotary shaft.

4. a third gear capable of transmitting power to an output side is provided on the second rotating shaft; the third gear meshes with a fourth gear disposed on a third rotary shaft on the output side, the third rotating shaft is a differential case of a differential mechanism including a differential gear that distributes power to a pair of output sides and a pair of output gears, 3. The power transmission device according to claim 1, wherein the second gear and the third gear are disposed on opposite sides of the differential mechanism in a direction of the rotation axis, spaced apart from each other.

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