Drive device

Abstract

To provide a driving device for a vehicle that can suppress an arrangement space from increasing to achieve reduction in weight.SOLUTION: The present invention relates to a driving device 1 in which: a speed change gear consists of a first speed change mechanism part 17 which reduces and transmits rotations of an input shaft 4 to an output shaft 6 and a second speed change mechanism part 18 which can transmit the rotations of the input shaft 4 to the output shaft 6 at a faster speed than the first speed change mechanism part 17. The first speed change mechanism 17 comprises a two-way clutch 8 which can transmit rotations of the input shaft 4 in a direction of a forward travel of the vehicle and rotations in a direction of a backward travel of the vehicle selectively to the output shaft 6, and the second speed change mechanism 18 comprises a wet type clutch 3 which can frictionally engage so as to transmit the rotations of the input shaft 4 in the direction of the forward travel of the vehicle to the output shaft 6.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present invention relates to a vehicle drive device for transmitting the driving force of a drive source.

Background Art

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a drive device for a vehicle including an electric motor as a drive source, an increase in the arrangement space and an increase in weight are concerns due to the improvement in performance of the vehicle or the electric motor or the complication of control including a transmission.

[0005] The present invention has been made in view of such a situation, and an object of the present invention is to provide a drive device for a vehicle for transmitting the driving force from a drive source, which can suppress an increase in the arrangement space and achieve weight reduction.

Means for Solving the Problems

[0006] To solve the above problems, the drive device of the present invention is an input shaft on the drive source side, and An output shaft that transmits the driving force of the aforementioned drive source to the drive wheel side, A drive system for a vehicle having a transmission mechanism that transmits the aforementioned driving force from the input shaft to the output shaft, The aforementioned transmission mechanism is A first speed control mechanism that reduces the rotation of the input shaft and transmits it to the output shaft, It consists of a second gearbox capable of transmitting the rotation of the input shaft to the output shaft at a faster speed than the first gearbox, The first transmission mechanism includes a two-way clutch capable of selectively transmitting rotation of the input shaft in the direction in which the vehicle moves forward and rotation of the input shaft in the direction in which the vehicle moves backward to the output shaft. The second gear shift mechanism is characterized by having a clutch mechanism that can transmit the rotation of the input shaft in the forward direction to the output shaft by frictional engagement. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a drive device for a vehicle that transmits driving force from a drive source, which can suppress an increase in installation space and reduce weight. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a skeleton diagram showing the configuration of the drive device according to the first embodiment of the first embodiment. [Figure 2] Figure 2 is a partial cross-sectional view of the main part of the drive unit along the axial direction. [Figure 3] Figure 3 is an enlarged cross-sectional view showing the main components of the two-way clutch, viewed from one side in the axial direction. [Figure 4] Figure 4 is a cross-sectional view of the main part of the two-way clutch, showing the state as viewed from one side in the axial direction. Figure 4(a) shows the state in which both the first and second claw members are engaged with the teeth. Figure 4(b) shows the state in which the first claw member is engaged with the teeth and the second claw member is not engaged with the teeth. Figure 4(c) shows the state in which neither the first nor the second claw member is engaged with the teeth. [Figure 5] Figure 5 is a skeleton diagram showing the configuration of the drive device according to the second embodiment of the first embodiment. [Figure 6] Figure 6 is a skeleton diagram showing the configuration of the drive device according to the first embodiment of the second embodiment. [Figure 7] Figure 7 is an enlarged cross-sectional view showing the main parts of the two-way clutch and planetary gear mechanism of the drive device according to the first embodiment of the second embodiment, and shows the state as viewed from one side in the axial direction. [Figure 8] Figure 8 is a skeleton diagram showing the configuration of the drive device according to the second embodiment of the second embodiment. [Figure 9] Figure 9 is an enlarged cross-sectional view showing the main parts of the two-way clutch and planetary gear mechanism of the drive device according to the second embodiment of the second model, and shows the state as viewed from one side in the axial direction. [Modes for carrying out the invention]

[0009] Hereinafter, the drive devices according to each embodiment of the present invention will be described with reference to the drawings. Each embodiment of the present invention is used in a vehicle whose drive source is an electric motor, and is of a type that transmits the driving force of the electric motor to the output shaft as low-speed rotation or high-speed rotation via a two-speed transmission.

[0010] First, we define the directions relating to the drive device according to each embodiment. In each embodiment, the axial direction refers to the axial direction of the input shaft connected to the drive shaft of the electric motor, and the output shaft from which the driving force of the electric motor is output. The axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction relating to the input shaft and the output shaft. Furthermore, regarding the axial direction, in Figures 1, 2, 5, 6, and 8, the left side of the paper is considered one axial direction, and the right side of the paper is considered the other axial direction. Regarding the circumferential direction, in Figures 3, 4, 7, and 9, the direction of rotation clockwise toward the plane of the paper is considered one circumferential direction, and the direction of rotation counterclockwise toward the plane of the paper is considered the other circumferential direction.

[0011] Hereinafter, the drive device according to the first embodiment of the first example of the present invention will be described while referring to the drawings. FIG. 1 is a skeleton diagram showing the configuration of a drive device 1 according to the first example of the first embodiment. FIG. 2 is a partial cross-sectional view along the axial direction of the main part of the drive device 1. FIG. 3 is a cross-sectional view showing the main part of the two-way clutch 8 and shows the state as viewed from one side in the axial direction.

[0012] As shown in FIG. 1, the drive device 1 according to the present example has an input shaft 4 connected to the drive shaft of the electric motor 2 and an output shaft 6 arranged in parallel with the input shaft 4. The driving force of the electric motor 2 is transmitted to the output shaft 6 from the input shaft 4 via a two-way clutch 8 or a friction engagement device 12, which will be described later.

[0013] In the present example, the input shaft 4 and the output shaft 6 are each formed in a columnar shape. On the input shaft 4, a first connecting gear 14 for transmitting the driving force of the electric motor 2 to the output shaft 6 at a low speed rotation and a second connecting gear 16 for transmitting the driving force from the electric motor 2 to the output shaft 6 at a high speed rotation are provided coaxially with the input shaft 4. The first connecting gear 14 and the second connecting gear 16 are arranged side by side in the axial direction in this order from one side in the axial direction to the other side in the axial direction. The second connecting gear 16 has a larger diameter than the first connecting gear 14. The first connecting gear 14 and the second connecting gear 16 are each provided on the input shaft 4 so as to be non-rotatable relative to the input shaft 4.

[0014] On the output shaft 6, a two-way clutch 8 and a friction engagement device 12 are provided coaxially with the output shaft 6. The two-way clutch 8 and the friction engagement device 12 are arranged in parallel in the axial direction in this order from one axial side to the other axial side. The two-way clutch 8 is connected to the first connecting gear 14 of the input shaft 4, and the friction engagement device 12 is connected to the second connecting gear 16 of the input shaft 4. The first connecting gear 14 and the two-way clutch 8 constitute a low-speed transmission mechanism part 17, and the second connecting gear 16 and the friction engagement device 12 constitute a high-speed transmission mechanism part 18. The low-speed transmission mechanism part 17 and the high-speed transmission mechanism part 18 constitute a two-speed transmission device. The driving device 1 transmits the driving force of the electric motor 2 to the output shaft 6 via the low-speed transmission mechanism part 17 when the speed of the vehicle (not shown) is in the low-speed range, and transmits it to the output shaft 6 via the high-speed transmission mechanism part 18 when the speed of the vehicle is in the high-speed range. The driving force of the electric motor 2 transmitted to the output shaft 6 is transmitted to a differential gear mechanism 23, which is a driving mechanism of the driving wheels 22, via an output gear 20 fixed to the output shaft 6.

[0015] As shown in FIGS. 2 and 3, the two-way clutch 8 has an annular outer ring 24 and a torque transmission mechanism capable of transmitting torque from the outer ring 24 to the inner ring. In the present embodiment, the inner ring of the two-way clutch 8 is the output shaft 6. Specifically, a diameter-expanded portion 6a formed on a portion of the output shaft 6 that faces the inner peripheral surface of the outer ring 24 in the radial direction is configured to engage with the torque transmission mechanism of the two-way clutch 8. The torque transmission mechanism in the present embodiment is a ratchet mechanism, and includes a plurality of first claw members 26 and a plurality of second claw members 28 provided at predetermined intervals in the circumferential direction on the inner peripheral portion of the outer ring 24 (see FIGS. 3 and 4). In FIG. 3, one first claw member 26 and one second claw member 28 adjacent to the first claw member 26 in the circumferential direction are shown.

[0016] Multiple teeth 30 are formed at equal intervals along the entire circumference of the enlarged diameter portion 6a of the output shaft 6. The teeth 30 protrude radially outward and extend axially. The teeth 30 constitute ratchet teeth that engage with the first claw member 26 and the second claw member 28. Specifically, one side of the teeth 30 in the circumferential direction constitutes a first engagement portion 30a that engages with the first claw member 26, and the other side of the teeth 30 in the circumferential direction constitutes a second engagement portion 30b that engages with the second claw member 28.

[0017] An annular low-speed gear 32 is positioned on the outer circumference of the outer ring 24. The low-speed gear 32 has a cylindrical portion 34 and an inward-facing flange portion 36 formed on the other axial side of the cylindrical portion 34. The low-speed gear 32 is fitted to the output shaft 6 so as to be rotatable relative to the output shaft 6 via a rolling bearing 38 fitted to the inner circumference of the inward-facing flange portion 36. The outer ring 24 of the two-way clutch 8 is fitted to the inner circumference of the cylindrical portion 34 of the low-speed gear 32. That is, the low-speed gear 32 and the outer ring 24 of the two-way clutch 8 rotate together. A gear 32a is formed on the outer circumference of the cylindrical portion 34 of the low-speed gear 32, and the gear 32a is always meshed with the first connecting gear 14 of the input shaft 4. Therefore, the outer ring 24 of the two-way clutch 8 and the first connecting gear 14 are always connected via the low-speed gear 32, and the input shaft 4 and the outer ring 24 of the two-way clutch 8 rotate in opposite directions to each other.

[0018] The first claw member 26 is held in a relief portion 42 provided on the inner circumference of the outer ring 24. The relief portion 42 is a recess that opens inward on the inner circumferential surface of the outer ring 24. The first claw member 26 has a predetermined circumferential length and is composed of a central portion 44 having a partially cylindrical outer surface, a protruding portion 46 projecting from the central portion 44 to one side in the circumferential direction, and a claw portion 48 projecting from the central portion 44 to the other side in the circumferential direction. The central portion 44 of the first claw member 26 is rotatably held in the relief portion 42. That is, the claw portion 48 of the first claw member 26 is held in the relief portion 42 so that it can swing radially around the central portion 44. The pivot point of the first claw member 26 is the central portion 44, but the center of gravity is in the claw portion 48. The claw portion 48 of the first claw member 26 is biased radially inward by a coil-shaped or other type of spring 50.

[0019] When the claw portion 48 of the first claw member 26 swings radially inward, the claw portion 48 engages with the first engagement portion 30a of the teeth portion 30 of the enlarged diameter portion 6a of the output shaft 6, thereby engaging the first claw member 26 with the teeth portion 30. By engaging with the teeth portion 30, the first claw member 26 locks the relative rotation of the output shaft 6 with respect to the outer ring 24 in the clockwise direction, i.e., in one circumferential direction. On the other hand, when the output shaft 6 rotates relative to the outer ring 24 in the counterclockwise direction, i.e., in the other circumferential direction, the first claw member 26 does not engage with the teeth portion 30, and allows the output shaft 6 to rotate in that direction.

[0020] The second claw member 28, like the first claw member 26, is held in a relief portion 52 provided on the inner circumference of the outer ring 24 and consists of a central portion 54, a protruding portion 56, and a claw portion 58. The claw portion 58 is biased radially inward by a spring 60, but its circumferential orientation is opposite to that of the first claw member 26. As a result, the second claw member 28 engages with the teeth 30 by the claw portion 58 engaging with the second meshing portion 30b of the teeth 30 of the enlarged diameter portion 6a of the output shaft 6. Unlike the first claw member 26, this locks the counterclockwise relative rotation of the output shaft 6 with respect to the outer ring 24, while allowing the clockwise relative rotation of the output shaft 6 with respect to the outer ring 24.

[0021] Thus, the ratchet mechanism is composed of the first claw member 26 and the second claw member 28 held on the inner circumference side of the outer ring 24, the springs 50 and 60, and the multiple teeth 30 formed on the enlarged diameter portion 6a of the output shaft 6.

[0022] In this embodiment, the two-way clutch 8 has different elastic forces for the spring 50 that biases the first claw member 26 and the spring 60 that biases the second claw member 28. Specifically, the elastic force of the spring 60 that biases the second claw member 28 is set to be smaller than the elastic force of the spring 50 that biases the first claw member 26. The elastic force of the spring 60 that biases the second claw member 28 is set to be such that it compresses by a predetermined amount when a predetermined force is applied, as will be explained below.

[0023] As described later, when the driving force of the electric motor 2 is transmitted to the outer ring 24 of the two-way clutch 8 and the outer ring 24 begins to rotate, the centrifugal force due to the rotation of the outer ring 24 acts on the first claw member 26 and the second claw member 28. When centrifugal force acts, since the centers of gravity of the first claw member 26 and the second claw member 28 are at the claw portions 48 and 58, respectively, the first claw member 26 and the second claw member 28 tend to swing in a direction where the claw portions 48 and 58 move radially outward around the central portions 44 and 54, respectively. As a result, the springs 50 and 60 that bias the first claw member 26 and the second claw member 28 are pressed radially outward, i.e., compressed, by the claw portions 48 and 58, respectively. As the rotation of the outer ring 24 increases and the centrifugal force acting on it increases, the spring 60 that biases the second claw member 28 is compressed by the claw portion 58. When the rotational speed of the outer ring 24 becomes faster than a predetermined rotational speed, and the centrifugal force acting on the second claw member 28 becomes greater than a predetermined magnitude F1, the spring 60 is greatly compressed by the claw portion 58, and the entire claw portion 58 is positioned radially outward from the teeth portion 30. In this state, the second claw member 28 and the teeth portion 30 are not engaged. Here, R1 is the predetermined rotational speed of the outer ring 24 at which a centrifugal force of a predetermined magnitude F1 is generated. Note that the spring 50 biasing the first claw member 26 does not become greatly compressed even when a centrifugal force of a predetermined magnitude F1 acts on the first claw member 26, and has elastic force that maintains engagement with the teeth portion 30.

[0024] The elastic force of springs 50 and 60, the predetermined centrifugal force F1 that causes spring 60 to be greatly compressed, and the predetermined rotational speed R1 of the outer ring 24 when the predetermined centrifugal force F1 is generated are designed appropriately, taking into consideration the magnitude of the transmitted torque, vehicle speed, etc.

[0025] Next, the configuration of the friction engagement device 12 will be described. As shown in Figure 2, the friction engagement device 12 in this embodiment is a wet clutch 3.

[0026] The wet clutch 3 has a cylindrical clutch case 7. The clutch case 7 is arranged coaxially with the output shaft 6. An inward-facing flange 9 is provided at one axial end of the clutch case 7, and a cylindrical member 68 is fitted into a hole 10 in the center of the inward-facing flange 9. More specifically, the clutch case 7 is fitted to the other axial end of the outer circumferential surface of the cylindrical member 68. The cylindrical member 68 is fitted to the output shaft 6 so as to be rotatable relative to the output shaft 6 via a rolling bearing 70. Thus, the clutch case 7 is fitted to the output shaft 6 so as to be rotatable relative to the output shaft 6 via the cylindrical member 68 and the rolling bearing 70.

[0027] As shown in Figure 2, multiple annular clutch plates 13 are fitted to the inner circumference of the clutch case 7 so as to be movable in the axial direction and unable to rotate relative to the clutch case 7. Further, multiple annular clutch discs 15 are arranged on the inner circumference of the clutch case 7. The multiple annular clutch discs 15 are fitted to the outer surface of a cylindrical clutch hub 62, which is concentric with the clutch case 7, so as to be movable in the axial direction and unable to rotate relative to the clutch hub 62. The clutch hub 62 is fixed to the output shaft 6 and rotates integrally with the output shaft 6. The multiple clutch plates 13 and multiple clutch discs 15 are arranged alternately in the axial direction.

[0028] An end plate 19 for holding the clutch plate 13 and clutch disc 15 in a fixed state at the other axial end of the inner circumference of the clutch case 7, and a retaining ring 21 for holding the end plate 19 inside the clutch case 7 are provided. The clutch plate 13 and clutch disc 15 are frictionally engaged with each other by being pressed in the axial direction by a piston 66 driven in the axial direction by a piston drive mechanism 64 arranged adjacent to the drive unit 1. This causes the wet clutch section 3 to be engaged. When the wet clutch section 3 is engaged, torque is transmitted from the clutch case 7 to the output shaft 6 via the clutch hub 62. Note that the piston drive mechanism 64 is not directly related to the present invention, so a detailed explanation is omitted.

[0029] A gear 83 is formed on one axial side of the outer circumferential surface of the cylindrical member 68. An annular high-speed gear 72 is positioned on the outer circumferential side of the gear 83 of the cylindrical member 68. The high-speed gear 72 has a smaller diameter than the low-speed gear 32 of the low-speed transmission mechanism 17 and is fitted to the output shaft 6 so as to be rotatable relative to the output shaft 6 via a rolling bearing 74 fitted to one axial side of the inner circumference of the high-speed gear 72. The gear portion 83 of the cylindrical member 68 is integrally fitted with the high-speed gear 72 to the other axial side of the inner circumference of the high-speed gear 72. As a result, the high-speed gear 72 and the clutch case 7 rotate together. A gear 72a is formed on the outer circumferential surface of the high-speed gear 72, and the gear 72a is always meshed with the second connecting gear 16 of the input shaft 4. Therefore, the clutch case 7 and the second connecting gear 16 are always connected via the high-speed gear 72, and the input shaft 4 and the clutch case 7 rotate in opposite directions to each other.

[0030] Next, the operation of the drive unit 1 according to this embodiment will be described. The following description of the operation is an example where the drive unit 1 is mounted on a vehicle (not shown). Furthermore, the following description of the operation is based on the view of the drive unit 1 from the front, with one axial side facing forward, as shown in Figures 1 and 2. Figure 4 is a cross-sectional view of the two-way clutch 8, showing the state as viewed from one side in the axial direction. Figure 4(a) shows the state in which both the first claw member 26 and the second claw member 28 are engaged with the teeth 30. Figure 4(b) shows the state in which the first claw member 26 is engaged with the teeth 30 and the second claw member 28 is not engaged with the teeth 30. Figure 4(c) shows the state in which neither the first claw member 26 nor the second claw member 28 is engaged with the teeth 30.

[0031] When a vehicle (not shown) starts moving forward from a stationary position, the input shaft 4 connected to the electric motor 2 rotates in one direction circumferentially. This rotation of the input shaft 4 is transmitted as a low-speed rotation to the outer ring 24 of the two-way clutch 8 via the first connecting gear 14 and the low-speed gear 32, causing the outer ring 24 of the two-way clutch 8 to rotate in the other direction circumferentially.

[0032] At this time, the multiple clutch plates 13 and multiple clutch discs 15 of the wet clutch 3 of the friction engagement device 12 are in a disengaged state. In other words, the wet clutch 3 is controlled to be in a disengaged state. In this state, the rotation of the input shaft 4 in one circumferential direction is transmitted to the clutch case 7 via the second connecting gear 16 and the high-speed gear 72, and the clutch case 7 rotates in the other circumferential direction, but no torque is transmitted to the output shaft 6 via the clutch hub 62. At this time, the clutch case 7 rotates in the other circumferential direction at a higher speed than the output shaft 6.

[0033] When the vehicle is stationary, the outer ring 24 of the two-way clutch 8 does not rotate, so no centrifugal force acts on the second claw member 28. Also, when low-speed rotation is input from the input shaft 4, the rotational speed of the outer ring 24 is slower than the predetermined rotational speed R1 described above. In other words, the predetermined rotational speed R1 of the outer ring 24 is set to be faster than the rotational speed of the outer ring 24 when low-speed rotation is input. Therefore, the magnitude of the centrifugal force acting on the second claw member 28 due to the rotation of the outer ring 24 when low-speed rotation is input is smaller than the predetermined magnitude F1 described above. For this reason, the spring 60 biasing the second claw member 28 is not compressed, and both the first claw member 26 and the second claw member 28 are meshed with the teeth 30, as shown in Figure 4(a). Therefore, in Figure 4(a), when the outer ring 24 rotates in the other direction in the circumferential direction, the output shaft 6 rotates integrally with the outer ring 24 in the other direction in the circumferential direction due to the meshing of the first claw member 26 and the teeth 30 of the enlarged diameter portion 6a of the output shaft 6, and the driving force from the electric motor 2 is transmitted to the output shaft 6. At this time, the rotational speed of the input shaft 4 is reduced and transmitted to the output shaft 6. The driving force from the electric motor 2 transmitted to the output shaft 6 is transmitted to the differential gear mechanism 23, which is the driving mechanism of the drive wheel 22, via the output gear 20 (see Figure 2) fitted to the output shaft 6.

[0034] Thus, when the vehicle starts and when driving at low speeds, the driving force from the electric motor 2 is transmitted from the input shaft 4 to the output shaft 6 via the low-speed transmission mechanism 17, or two-way clutch 8.

[0035] Next, we will explain the operation of the drive unit 1 when the transmission of the drive unit 1 shifts from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18. When the vehicle starts moving and accelerates, the transmission of the drive unit 1 shifts from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18. When the vehicle accelerates, the rotational speed of the input shaft 4 connected to the electric motor 2 increases, and the rotational speed of the outer ring 24 of the two-way clutch 8 increases. Consequently, the centrifugal force acting on the second claw member 28 increases. When the rotational speed of the outer ring 24 exceeds a predetermined rotational speed R1, and the magnitude of the centrifugal force acting on the second claw member 28 exceeds a predetermined magnitude F1, the spring 60 biasing the second claw member 28 is greatly compressed by the claw portion 58, and the entire claw portion 58 is positioned radially outward from the teeth portion 30. In this state, as shown in Figure 4(b), the first claw member 26 of the two-way clutch 8 maintains engagement with the teeth portion 30, but the second claw member 28 is not engaged with the teeth portion 30.

[0036] In this state, the wet clutch 3 is controlled to switch from a disengaged state to an engaged state. Specifically, the piston 66 is driven by the piston drive mechanism 64, and the multiple clutch plates 13 and multiple clutch discs 15 of the wet clutch 3 are pressed axially and frictionally engage with each other. This causes the wet clutch 3 to be engaged. As described above, when the input is at low speed, i.e., when the wet clutch 3 is disengaged, the clutch case 7 rotates in the other circumferential direction at a higher speed than the output shaft 6. When the wet clutch 3 is engaged in this state, the clutch case 7, clutch hub 62, and output shaft 6 rotate together in the other circumferential direction, and high-speed rotation is transmitted from the clutch case 7 to the output shaft 6 via the clutch hub 62. That is, the driving force of the electric motor 2 is transmitted to the output shaft 6 as high-speed rotation. At this time, the rotation of the input shaft 4 is not reduced, but is transmitted to the output shaft 6 at a constant speed or even at an increased speed. Alternatively, if the rotation of the input shaft 4 is reduced and transmitted to the output shaft 6, the reduction rate is smaller than when it is transmitted via the low-speed gear 32.

[0037] When the driving force of the electric motor 2 is transmitted to the output shaft 6 as high-speed rotation, the rotational speed of the output shaft 6 in the other circumferential direction increases. As the rotational speed of the output shaft 6 increases, it becomes faster than the rotational speed of the outer ring 24 of the two-way clutch 8, which rotates integrally with the low-speed gear 32. That is, in Figure 4(b), the output shaft 6 rotates relative to the outer ring 24 of the two-way clutch 8 in the other circumferential direction. As a result, the first claw member 26 has its claw portion 48 pushed radially outward by the teeth portion 30 against the biasing force of the spring 50, resulting in a disengaged state with the teeth portion 30, allowing the output shaft 6 to rotate in the other circumferential direction. Therefore, as shown in Figure 4(c), both the first claw member 26 and the second claw member 28 of the two-way clutch 8 are disengaged from the teeth portion 30, and no driving force is transmitted from the outer ring 24 to the output shaft 6. In other words, the driving force from the electric motor 2 is transmitted from the input shaft 4 to the output shaft 6 via the high-speed transmission mechanism 18, or friction engagement device 12.

[0038] During high-speed driving after shifting from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18, the two-way clutch 8, which is always connected to the low-speed gear 32, is in a free-spinning state, and no torque is transmitted to the output shaft 6 via the two-way clutch 8.

[0039] Next, we will explain the operation of the drive unit 1 when the vehicle is moving in reverse. When the vehicle moves in reverse, the input shaft 4, which is connected to the electric motor 2, rotates in the other direction in the circumferential direction. When the vehicle moves in reverse, the wet clutch 3 of the friction engagement device 12 is controlled to be disengaged, and the rotation of the input shaft 4 is transmitted as a low-speed rotation to the two-way clutch 8 via the first connecting gear 14 and the low-speed gear 32, and then transmitted to the output shaft 6 via the two-way clutch 8. At this time, as shown in Figure 4(a), the first claw member 26 and the second claw member 28 of the two-way clutch 8 are both meshed with the teeth 30. Therefore, when the outer ring 24 of the two-way clutch 8 rotates in one direction in the circumferential direction in Figure 4(a), the output shaft 6 rotates in one direction in the circumferential direction together with the outer ring 24 due to the meshing of the second claw member 28 with the teeth 30 of the enlarged diameter portion 6a of the output shaft 6. In this way, when the vehicle moves in reverse, the driving force from the electric motor 2 is transmitted to the output shaft 6.

[0040] Thus, according to the drive device 1 of this embodiment, the structure can be simplified, the increase in installation space can be suppressed, and the weight can be reduced.

[0041] Next, the drive device 11 according to the second embodiment of the first embodiment will be described. In describing the second embodiment, the same reference numerals will be used with reference to Figures 1 to 4 for components similar to those in the first embodiment, and a detailed explanation of these components will be omitted.

[0042] Figure 5 is a skeleton diagram showing the configuration of the drive unit 11 according to the second embodiment of the first embodiment. The drive unit 11 of this embodiment, like the first embodiment described above, has an input shaft 4 connected to the drive shaft of the electric motor 2 and an output shaft 6 arranged parallel to the input shaft 4. The driving force of the electric motor 2 is transmitted to the output shaft 6 from the input shaft 4 via a two-way clutch 8 or a friction engagement device 12. The difference in configuration between the drive unit 11 of this embodiment and the first embodiment is that the friction engagement device 12 is provided on the input shaft 4 and the second connecting gear 16 is provided on the output shaft. The other configurations are the same as in the first embodiment.

[0043] As shown in Figure 5, the input shaft 4 is coaxially equipped with a friction engagement device 12 for transmitting the driving force from the electric motor 2 to the output shaft 6 at high speed rotation, and a first connecting gear 14 for transmitting the driving force from the electric motor 2 to the output shaft 6 at low speed rotation. The friction engagement device 12 and the first connecting gear 14 are arranged in the axial direction in this order, from one axial side to the other axial side. The first connecting gear 14 is mounted on the input shaft 4 so as to be unable to rotate relative to the input shaft 4.

[0044] The friction engagement device 12 is a wet clutch 3 with the same configuration as in the first embodiment (see Figure 2). The wet clutch 3 has a clutch hub 62 fixed to the input shaft 4 and rotating integrally with the input shaft 4, and a clutch case 7 fitted to the input shaft 4 so as to be rotatable relative to the input shaft 4. Inside the clutch case 7, a clutch plate 13 and a clutch disc 15 are provided, similar to the first embodiment. A high-speed gear 72 is connected to the clutch case 7. The high-speed gear 72 has a larger diameter than the first connecting gear 14. The clutch case 7 and the high-speed gear 72 rotate integrally.

[0045] A second connecting gear 16 and a two-way clutch 8 are mounted coaxially on the output shaft 6. The second connecting gear 16 and the two-way clutch 8 are mounted in this order axially, from one axial side to the other axial side.

[0046] The two-way clutch 8 has the same configuration as in the first embodiment (see Figures 2 and 3). That is, the two-way clutch 8 has an annular outer ring 24 and a ratchet mechanism which is a torque transmission mechanism, and the output shaft 6 constitutes the inner ring of the two-way clutch 8. Similar to the first embodiment, an annular low-speed gear 32 is arranged on the outer circumference of the outer ring 24, and the outer ring 24 and the low-speed gear 32 rotate together. The low-speed gear 32 is always meshed with the first connecting gear 14 of the input shaft 4. Therefore, the outer ring 24 of the two-way clutch 8 and the first connecting gear 14 are always connected via the low-speed gear 32, and the input shaft 4 and the outer ring 24 of the two-way clutch 8 rotate in opposite directions to each other. The first connecting gear 14 and the two-way clutch 8 constitute the low-speed transmission mechanism 17.

[0047] The second connecting gear 16 has a smaller diameter than the low-speed gear 32 of the low-speed transmission mechanism 17 and is mounted on the output shaft 6 so as not to rotate relative to the output shaft 6. The second connecting gear 16 is always meshed with the high-speed gear 72 of the friction engagement device 12. Therefore, the clutch case 7 of the friction engagement device 12 and the second connecting gear 16 are always connected via the high-speed gear 72, and the input shaft 4 and the clutch case 7 rotate in opposite directions to each other. The second connecting gear 16 and the friction engagement device 12 constitute the high-speed transmission mechanism 18. The low-speed transmission mechanism 17 and the high-speed transmission mechanism 18 constitute a two-speed transmission.

[0048] The driving force of the electric motor 2, transmitted from the input shaft 4 to the output shaft 6 via the transmission, is transmitted to the differential gear mechanism 23, which is the drive mechanism for the drive wheels 22, via the output gear 20 fixed to the output shaft 6, similar to the first embodiment.

[0049] Next, the operation of the drive unit 11 according to this embodiment will be described. The following description of the operation will be based on the view of the drive unit 11 from the front, with one axial side facing forward as shown in Figure 5.

[0050] When a vehicle (not shown) starts moving forward from a stationary position, the input shaft 4 connected to the electric motor 2 rotates in one direction circumferentially. This rotation of the input shaft 4 is transmitted as a low-speed rotation to the outer ring 24 of the two-way clutch 8 via the first connecting gear 14 and the low-speed gear 32, causing the outer ring 24 of the two-way clutch 8 to rotate in the other direction circumferentially.

[0051] At this time, the multiple clutch plates 13 and multiple clutch discs 15 (see Figure 2) of the wet clutch 3 of the friction engagement device 12 are in a disengaged state. In other words, the wet clutch 3 is controlled to be in a disengaged state. In this state, rotation in one circumferential direction of the input shaft 4 is not transmitted from the clutch hub 62, which rotates integrally with the input shaft 4, to the clutch case 7.

[0052] As explained in the first embodiment, when the vehicle is stopped, the outer ring 24 of the two-way clutch 8 does not rotate, so no centrifugal force acts on the second claw member 28. Also, when low-speed rotation is input from the input shaft 4, the rotational speed of the outer ring 24 is slower than the predetermined rotational speed R1, and the magnitude of the centrifugal force acting on the second claw member 28 is smaller than the predetermined magnitude F1. For this reason, the spring 60 biasing the second claw member 28 is not compressed, and both the first claw member 26 and the second claw member 28 are meshed with the teeth 30 (see Figure 4(a)). Therefore, in this embodiment as well, as in the first embodiment, when the outer ring 24 rotates in the other direction in the circumferential direction in Figure 4(a), the output shaft 6 rotates together with the outer ring 24 in the other direction in the circumferential direction due to the meshing of the first claw member 26 with the teeth 30 of the output shaft 6, and the driving force from the electric motor 2 is transmitted to the output shaft 6. At this time, the rotational speed of the input shaft 4 is reduced and transmitted to the output shaft 6. The driving force from the electric motor 2 transmitted to the output shaft 6 is transmitted to the differential gear mechanism 23, which is the drive mechanism for the drive wheels 22, via the output gear 20 (see Figure 2) fitted to the output shaft 6.

[0053] In this state, the second connecting gear 16 rotates integrally with the output shaft 6 in the other direction in the circumferential direction. The rotation of the second connecting gear 16 is transmitted to the clutch case 7 via the high-speed gear 72, causing the clutch case 7 to rotate in one direction in the circumferential direction. However, since the wet clutch 3 is controlled to be disengaged, the clutch case 7 is free-spinning relative to the input shaft 4 and the clutch hub 62. At this time, the clutch case 7 rotates in one direction in the circumferential direction at a lower speed than the input shaft 4.

[0054] Thus, when the vehicle starts and when driving at low speeds, the driving force from the electric motor 2 is transmitted from the input shaft 4 to the output shaft 6 via the low-speed transmission mechanism 17, or two-way clutch 8.

[0055] Next, we will explain the operation of the drive unit 1 when the transmission of the drive unit 11 shifts from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18. When the vehicle starts moving and accelerates, the transmission of the drive unit 11 shifts from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18. When the vehicle accelerates and the rotational speed of the outer wheel 24 exceeds a predetermined rotational speed R1, and the magnitude of the centrifugal force acting on the second claw member 28 exceeds a predetermined magnitude F1, the spring 60 biasing the second claw member 28 is greatly compressed by the claw portion 58, and the entire claw portion 58 is positioned radially outward from the teeth portion 30. In this state, as shown in Figure 4(b), the two-way clutch 8 maintains the engagement state of the first claw member 26 with the teeth portion 30, but the second claw member 28 is not engaged with the teeth portion 30.

[0056] In this state, the wet clutch 3 is controlled to switch from a disengaged state to an engaged state, similar to the first embodiment. Specifically, the piston 66 is driven by the piston drive mechanism 64, and the wet clutch 3 is engaged. As described above, when the input is at low speed, i.e., when the wet clutch 3 is disengaged, the clutch case 7 rotates in one direction circumferentially at a lower speed than the input shaft 4. When the wet clutch 3 is engaged in this state, the input shaft 4, clutch hub 62, and clutch case 7 rotate together in one direction circumferentially, and high-speed rotation is transmitted from the clutch case 7 to the output shaft 6 via the high-speed gear 72 and the second connecting gear 16. In other words, the driving force of the electric motor 2 is transmitted to the output shaft 6 as high-speed rotation.

[0057] When the driving force of the electric motor 2 is transmitted to the output shaft 6 as high-speed rotation, the rotational speed of the output shaft 6 in the other circumferential direction increases. As the rotational speed of the output shaft 6 increases, it becomes faster than the rotational speed of the outer ring 24 of the two-way clutch 8, which rotates integrally with the low-speed gear 32. That is, in Figure 4(b), the output shaft 6 rotates relative to the outer ring 24 of the two-way clutch 8 in the other circumferential direction. As a result, the first claw member 26 has its claw portion 48 pushed radially outward by the teeth portion 30 against the biasing force of the spring 50, resulting in a disengaged state with the teeth portion 30, allowing the output shaft 6 to rotate in the other circumferential direction. Therefore, as shown in Figure 4(c), both the first claw member 26 and the second claw member 28 of the two-way clutch 8 are disengaged from the teeth portion 30, and no driving force is transmitted from the outer ring 24 to the output shaft 6. In other words, the driving force from the electric motor 2 is transmitted from the input shaft 4 to the output shaft 6 via the high-speed transmission mechanism 18, or friction engagement device 12.

[0058] During high-speed driving after shifting from the low-speed transmission mechanism 17 to the high-speed transmission mechanism 18, the two-way clutch 8, which is always connected to the low-speed gear 32, is in a free-spinning state, and no torque is transmitted to the output shaft 6 via the two-way clutch 8.

[0059] Next, we will explain the operation of the drive unit 1 when the vehicle is moving in reverse. When the vehicle moves in reverse, the input shaft 4, which is connected to the electric motor 2, rotates in the other direction in the circumferential direction. When the vehicle moves in reverse, the wet clutch 3 of the friction engagement device 12 is controlled to be disengaged, and the rotation of the input shaft 4 is transmitted as a low-speed rotation to the two-way clutch 8 via the first connecting gear 14 and the low-speed gear 32, and then transmitted to the output shaft 6 via the two-way clutch 8. At this time, as shown in Figure 4(a), the first claw member 26 and the second claw member 28 of the two-way clutch 8 are both meshed with the teeth 30. Therefore, when the outer ring 24 of the two-way clutch 8 rotates in one direction in the circumferential direction in Figure 4(a), the output shaft 6 rotates in one direction in the circumferential direction together with the outer ring 24 due to the meshing of the second claw member 28 with the teeth 30 of the enlarged diameter portion 6a of the output shaft 6. In this way, when the vehicle moves in reverse, the driving force from the electric motor 2 is transmitted to the output shaft 6.

[0060] Thus, according to the drive device 11 of this embodiment, the structure can be simplified, the increase in installation space can be suppressed, and the weight can be reduced, similar to the first embodiment.

[0061] Next, a drive device according to a second embodiment of the present invention will be described. Unlike the first embodiment, the drive device according to the second embodiment of the present invention is of a type in which the input shaft, which receives the driving force from the electric motor, and the output shaft, which outputs the driving force to the drive unit, are arranged on the same axis. In the description of each embodiment of the second embodiment, the same reference numerals will be used with reference to Figures 1 to 5 for the same configuration as in the first embodiment, and a detailed description of these configurations will be omitted.

[0062] First, the drive unit 101 according to the first embodiment of the second embodiment will be described. Figure 6 is a skeleton diagram showing the configuration of the drive unit 101 according to the first embodiment of the second embodiment. Figure 7 is an enlarged cross-sectional view showing the main parts of the two-way clutch 108 and planetary gear mechanism 127 of the drive unit 101 according to this embodiment, and shows the state as viewed from one side in the axial direction. As shown in Figure 6, the drive unit 101 according to this embodiment has an input shaft 104 connected to the drive shaft of the electric motor 2, and an output shaft 106 arranged on the same axis as the input shaft 104. The driving force of the electric motor 2 is transmitted to the output shaft 106 from the input shaft 104 via a transmission. The transmission includes a two-way clutch 108, a planetary gear mechanism 127, and a friction engagement device 12.

[0063] In this embodiment, the input shaft 104 is formed in a cylindrical shape. A two-way clutch 108 and a friction engagement device 12 are provided coaxially with the input shaft 104 on its outer circumference. The two-way clutch 108 and the friction engagement device 12 are arranged in the axial direction in this order, from one axial side to the other axial side.

[0064] In this embodiment, the input shaft 104 constitutes the inner ring of the two-way clutch 108. Specifically, portion 104a of the input shaft 104 constitutes the inner ring of the two-way clutch 108. As shown in Figure 7, a plurality of teeth 30 are formed on the outer circumference of portion 104a of the input shaft 104 in the circumferential direction. The configuration of the teeth 30 is the same as in the first embodiment. The outer ring 124 of the two-way clutch 108 is provided with a plurality of first claw members 26 and second claw members 28, each with the same configuration as in the first embodiment. A gear 125 is formed on the outer circumference of the outer ring 124 in the circumferential direction.

[0065] The drive unit 101 of this embodiment includes a planetary gear mechanism 127 in which the outer ring 124 of the two-way clutch 108 is a sun gear. The planetary gear mechanism 127 includes the sun gear which is the outer ring 124 of the two-way clutch 108, a plurality of planetary gears 129 that mesh with the sun gear, a planetary carrier 131 that supports each of the plurality of planetary gears 129 so that they can rotate, and a ring gear 133 that meshes with the plurality of planetary gears 129. The ring gear 133 is fixed to the transmission case 135, for example, in a way that prevents it from rotating.

[0066] The two-way clutch 108 transmits the driving force of the electric motor 2 from the input shaft 104 to the planetary carrier 131 via the planetary gear 129 by engaging the teeth 30 of the input shaft 104 with either the first claw member 26 or the second claw member 28. The planetary carrier 131 is connected to the output shaft 106.

[0067] The friction engagement device 12 is a wet clutch 3 having the same configuration as in the first embodiment, with the clutch hub 62 fixed to the input shaft 104 and the clutch case 7 connected to the planetary carrier 131 of the planetary gear mechanism 127. The wet clutch 3 is switched between a engaged state and a disengaged state by a piston drive mechanism 64 (see Figure 2) similar to that of the first embodiment. In the engaged state, the wet clutch 3 integrally connects the input shaft 104 and the planetary carrier 131.

[0068] The driving force of the electric motor 2, transmitted from the input shaft 104 to the output shaft 106 via the transmission, is transmitted to the differential gear mechanism 23, which is the drive mechanism for the drive wheels 22, similar to the first embodiment.

[0069] Next, the operation of the drive unit 101 according to this embodiment will be described. The following description of the operation will be based on the view of the drive unit 101 from the front, with one axial side facing forward as shown in Figure 6.

[0070] When a vehicle (not shown) starts moving forward from a stationary position, the inner ring of the input shaft 104, i.e., the two-way clutch 108, which is connected to the electric motor 2, rotates in one direction circumferentially as shown in Figure 7. At this time, the wet clutch 3 is controlled to be in a free-spinning state, i.e., disengaged state. Also, similar to the first embodiment, when the rotational speed of the outer ring 124 of the two-way clutch 108 is slower than a predetermined rotational speed R1 and the magnitude of the centrifugal force acting on the second claw member 28 is smaller than a predetermined magnitude F1, i.e., when the vehicle is stationary or the vehicle is moving at a low speed, both the first claw member 26 and the second claw member 28 are engaged with the teeth 30 of the input shaft 104. Therefore, in Figure 7, when the input shaft 104, i.e., the inner ring of the two-way clutch 108, rotates in one direction in the circumferential direction, the two-way clutch 108 transmits the torque of the electric motor 2 from the inner ring, which is the input shaft 104, to the outer ring 124, which is the sun gear of the planetary gear mechanism 127, through the meshing of the first claw member 26 and the teeth 30, causing the outer ring 124 to rotate in one direction in the circumferential direction.

[0071] When the outer ring 124 of the two-way clutch 108 rotates in one direction circumferentially, the rotation of the outer ring 124 is transmitted to the planetary carrier 131 via multiple planetary gears 129, causing the planetary carrier 131 to rotate in one direction circumferentially. At this time, the rotation of the outer ring 124 is reduced in speed before being transmitted to the planetary carrier 131. In this way, the torque of the electric motor 2 is transmitted as a low-speed rotation from the planetary carrier 131 to the output shaft 106, causing the output shaft 106 to rotate in one direction circumferentially. The driving force from the electric motor 2 transmitted to the output shaft 106 is transmitted to the differential gear 23, which is the drive mechanism for the drive wheel 22, via the output gear 120 fitted to the output shaft 106.

[0072] Thus, when the vehicle starts moving and when traveling at low speeds, the driving force from the electric motor 2 is transmitted from the input shaft 104 to the output shaft 106 via the two-way clutch 108 and the planetary gear mechanism 127. In other words, the two-way clutch 108 and the planetary gear mechanism 127 constitute the low-speed transmission mechanism 117.

[0073] Next, we will explain the operation of the drive unit 101 when the transmission of the drive unit 101 changes from a low-speed state to a high-speed state. As the vehicle accelerates and the rotational speed of the outer ring 124 of the sun gear, i.e., the two-way clutch 108, of the planetary gear mechanism 127 exceeds a predetermined rotational speed R1, and the magnitude of the centrifugal force acting on the second claw member 28 exceeds a predetermined magnitude F1, the spring 60 biasing the second claw member 28 is greatly compressed by the claw portion 58, and the entire claw portion 58 is positioned radially outward from the teeth portion 30. In this state, the two-way clutch 108 maintains the engagement state of the first claw member 26 with the teeth portion 30, but the second claw member 28 is not engaged with the teeth portion 30.

[0074] In this state, the wet clutch 3 is controlled to switch from a disengaged state to an engaged state. Specifically, the piston 66 (see Figure 2) is driven by the piston drive mechanism 64, and the wet clutch 3 is engaged. When the wet clutch 3 is engaged, the input shaft 104 and the planetary carrier 131 rotate together in one direction in the circumferential direction, and high-speed rotation is transmitted from the clutch hub 62 to the planetary carrier 131 via the clutch case 7. At this time, the rotation of the input shaft 104 is not reduced and is transmitted to the planetary carrier 131 at a constant speed. In this way, the driving force of the electric motor 2 is transmitted to the output shaft 104 as high-speed rotation. In other words, the wet clutch 3 constitutes the high-speed transmission mechanism 118.

[0075] During high-speed driving after shifting from a low-speed state to a high-speed state, the input shaft 104 and the planetary carrier 131 rotate at a constant speed in one direction circumferentially. At this time, the outer ring 124 of the sun gear, or two-way clutch 108, rotates in one direction circumferentially at a faster speed than the planetary carrier 131 due to the rotational input from the planetary carrier 131 via the planetary gear 129. In other words, the outer ring 124 rotates in one direction circumferentially at a faster speed than the input shaft 104. As a result, the first claw member 26 has its claw portion 48 pushed radially outward by the teeth portion 30 against the biasing force of the spring 50, resulting in a non-engaging state with the teeth portion 30, and allowing the outer ring 124 to rotate relative to the input shaft 104 in one direction circumferentially. In other words, no driving force is transmitted from the input shaft 104 to the outer ring 124 via the two-way clutch 108.

[0076] When the vehicle moves in reverse, the inner ring of the input shaft 104, or the two-way clutch 108, which is connected to the electric motor 2, rotates in the opposite direction circumferentially in Figure 7. At this time, the wet clutch 3 is controlled to be in a free-spinning state, or disengaged state. The two-way clutch 108 has both a first claw member 26 and a second claw member 28 that mesh with the teeth 30 of the input shaft 104. Therefore, when the inner ring of the input shaft 104, or the two-way clutch 108, rotates in the opposite direction circumferentially in Figure 7, the two-way clutch 108 transmits the torque of the electric motor 2 from the inner ring, which is the input shaft 104, to the outer ring 124, which is the sun gear of the planetary gear mechanism 127, through the meshing of the second claw member 28 and the teeth 30, causing the outer ring 124 to rotate in the opposite direction circumferentially. When the outer ring 124 of the two-way clutch 108 rotates in the other direction circumferentially, the rotation of the outer ring 124 is transmitted to the planetary carrier 131 via multiple planetary gears 129, causing the planetary carrier 131 to rotate in the other direction circumferentially, and the output shaft 106 to rotate in the other direction circumferentially. In this way, when the vehicle moves in reverse, the driving force from the electric motor 2 is transmitted to the output shaft 106.

[0077] Next, the drive unit 201 according to the second embodiment of the second embodiment will be described. Figure 8 is a skeleton diagram showing the configuration of the drive unit 201 according to the second embodiment of the second embodiment. Figure 9 is an enlarged cross-sectional view showing the main parts of the two-way clutch and planetary gear mechanism 227 of the drive unit 201 according to this embodiment, and shows the state as viewed from one side in the axial direction. As shown in Figure 8, the drive unit 201 according to this embodiment, similar to the first embodiment described above, has an input shaft 204 connected to the drive shaft of the electric motor 2 and an output shaft 206 arranged on the same axis as the input shaft 204. The driving force of the electric motor 2 is transmitted to the output shaft 206 from the input shaft 204 via a transmission. The transmission includes a two-way clutch 208, a planetary gear mechanism 227, and a friction engagement device 12.

[0078] In this embodiment, the input shaft 204 is formed in a cylindrical shape. A two-way clutch 208 and a friction engagement device 12 are provided coaxially with the input shaft 204 on the inner circumference of the input shaft 204. The two-way clutch 208 and the friction engagement device 12 are arranged in the axial direction in this order, from one axial side to the other axial side.

[0079] In this embodiment, the input shaft 204 constitutes the outer ring of the two-way clutch 208. As shown in Figure 9, the inner circumference of the input shaft 204 is provided with multiple first claw members 26 and second claw members 28, each having the same configuration as in the first embodiment. Multiple teeth 30 are formed on the outer circumference of the inner ring 237 of the two-way clutch 208 in the circumferential direction. The configuration of the teeth 30 is the same as in the first embodiment. A gear 239 is formed on the inner circumference of the inner ring 237 of the two-way clutch 208 in the circumferential direction.

[0080] The drive unit 201 of this embodiment includes a planetary gear mechanism 227 in which the inner ring 237 of the two-way clutch 208 is a ring gear. The planetary gear mechanism 227 includes a ring gear which is the inner ring 237 of the two-way clutch 208, a plurality of planetary gears 229 that mesh with the ring gear, a planetary carrier 231 that supports the plurality of planetary gears 229 so that they can rotate, and a sun gear 241 that meshes with the plurality of planetary gears 229. The sun gear 241 is fixed to the transmission case 135, for example, in a way that prevents it from rotating.

[0081] The two-way clutch 208 transmits the driving force of the electric motor 2 from the input shaft 204, which is the outer ring, to the planetary carrier 231 via the planetary gear 229, by the engagement of the first claw member 26 or the second claw member 28 with the teeth 30 of the inner ring 237. The planetary carrier 231 is connected to the output shaft 206.

[0082] The friction engagement device 12 is a wet clutch 3 having the same configuration as in the first embodiment, with the clutch case 7 connected to the input shaft 204 and the clutch hub 62 connected to the planetary carrier 231 of the planetary gear mechanism 227. The wet clutch 3 is switched between a engaged state and a disengaged state by a piston drive mechanism 64 (see Figure 2) similar to that of the first embodiment. In the engaged state, the wet clutch 3 integrally connects the input shaft 204 and the planetary carrier 231.

[0083] The driving force of the electric motor 2, transmitted from the input shaft 204 to the output shaft 206 via the transmission, is transmitted to the differential gear mechanism 23, which is the drive mechanism for the drive wheels 22, similar to the first embodiment.

[0084] Next, the operation of the drive unit 201 according to this embodiment will be described. The following description of the operation will be based on the view of the drive unit 201 from the front, with one axial side facing forward as shown in Figure 8.

[0085] When a vehicle (not shown) starts moving forward from a stationary position, the outer ring of the input shaft 204, i.e., the two-way clutch 208, which is connected to the electric motor 2, rotates in the other direction circumferentially in Figure 9. At this time, the wet clutch 3 is controlled to be in a free-spinning state, i.e., disengaged state. Also, similar to the first embodiment, when the rotational speed of the outer ring of the two-way clutch 208 is slower than a predetermined rotational speed R1 and the magnitude of the centrifugal force acting on the second claw member 28 is smaller than a predetermined magnitude F1, i.e., when the vehicle is stationary or the vehicle is moving at a low speed, both the first claw member 26 and the second claw member 28 are engaged with the teeth 30 of the inner ring 237. Therefore, in Figure 9, when the input shaft 204, i.e., the outer ring of the two-way clutch 208, rotates in the other direction in the circumferential direction, the two-way clutch 208 transmits the torque of the electric motor 2 from the outer ring, which is the input shaft 204, to the inner ring 237, which is the ring gear of the planetary gear mechanism 227, through the meshing of the first claw member 26 and the teeth 30, causing the inner ring 237 to rotate in the other direction in the circumferential direction.

[0086] When the inner ring 237 of the two-way clutch 208 rotates in the other direction in the circumferential direction, the rotation of the inner ring 237 is transmitted to the planetary carrier 231 via multiple planetary gears 229, causing the planetary carrier 231 to rotate in the other direction in the circumferential direction. At this time, the rotation of the inner ring 237 is reduced in speed before being transmitted to the planetary carrier 231. In this way, the torque of the electric motor 2 is transmitted as a low-speed rotation from the planetary carrier 231 to the output shaft 206, causing the output shaft 206 to rotate in the other direction in the circumferential direction. The driving force from the electric motor 2 transmitted to the output shaft 206 is transmitted to the differential gear 23, which is the drive mechanism for the drive wheel 22, via the output gear 220 fitted to the output shaft 206.

[0087] Thus, when the vehicle starts moving and when traveling at low speeds, the driving force from the electric motor 2 is transmitted from the input shaft 204 to the output shaft 206 via the two-way clutch 208 and the planetary gear mechanism 227. In other words, the two-way clutch 208 and the planetary gear mechanism 227 constitute the low-speed transmission mechanism 217.

[0088] Next, we will explain the operation of the drive unit 201 when the transmission of the drive unit 201 changes from a low-speed state to a high-speed state. When the vehicle accelerates and the rotational speed of the input shaft 204, i.e., the outer ring of the two-way clutch 208, exceeds a predetermined rotational speed R1, and the magnitude of the centrifugal force acting on the second claw member 28 exceeds a predetermined magnitude F1, the spring 60 biasing the second claw member 28 is greatly compressed by the claw portion 58, and the entire claw portion 58 is positioned radially outward from the teeth portion 30. In this state, the two-way clutch 208 maintains the engagement state of the first claw member 26 with the teeth portion 30, but the second claw member 28 is disengaged from the teeth portion 30.

[0089] In this state, the wet clutch 3 is controlled to switch from a disengaged state to an engaged state. Specifically, the piston 66 (see Figure 2) is driven by the piston drive mechanism 64, and the wet clutch 3 is engaged. When the wet clutch 3 is engaged, the input shaft 204, that is, the outer ring of the two-way clutch 208 and the planetary carrier 231 rotate together in the other circumferential direction, and high-speed rotation is transmitted from the clutch case 7 to the planetary carrier 231 via the clutch hub 62. At this time, the rotation of the input shaft 204 is not reduced and is transmitted to the planetary carrier 231 at a constant speed. In this way, the driving force of the electric motor 2 is transmitted to the output shaft 206 as high-speed rotation. In other words, the wet clutch 3 constitutes the high-speed transmission mechanism 218.

[0090] During high-speed driving after shifting from a low-speed state to a high-speed state, the input shaft 204, i.e., the outer ring of the two-way clutch 208, and the planetary carrier 231 rotate at a constant speed in the opposite direction in the circumferential direction. At this time, the ring gear, i.e., the inner ring 237 of the two-way clutch, rotates in the opposite direction in the circumferential direction at a faster speed than the planetary carrier 231 due to the rotational input from the planetary carrier 231 via the planetary gear 229. In other words, the inner ring 237 rotates in the opposite direction in the circumferential direction at a faster speed than the input shaft 204. As a result, the first claw member 26 has its claw portion 48 pushed radially outward by the teeth portion 30 against the biasing force of the spring 50, resulting in a non-engaging state with the teeth portion 30, and allowing the inner ring 237 to rotate relative to the input shaft 204 in the opposite direction in the circumferential direction. In other words, no driving force is transmitted from the input shaft 204 to the inner ring 237 via the two-way clutch 208.

[0091] When the vehicle moves in reverse, the outer ring of the input shaft 204, which is connected to the electric motor 2, i.e., the bidirectional clutch 208, rotates in one direction circumferentially as shown in Figure 9. At this time, the wet clutch 3 is controlled to be in a free-spinning state, i.e., disengaged state. The bidirectional clutch 208 has both a first claw member 26 and a second claw member 28 that mesh with the teeth 30 of the inner ring 237. Therefore, when the outer ring of the input shaft 204, i.e., the bidirectional clutch 208, rotates in one direction circumferentially as shown in Figure 9, the bidirectional clutch 208 transmits the torque of the electric motor 2 from the outer ring, which is the input shaft 204, to the inner ring 237, which is the ring gear of the planetary gear mechanism 227, through the meshing of the second claw member 28 and the teeth 30, causing the inner ring 237 to rotate in one direction circumferentially. When the inner ring 237 of the two-way clutch 208 rotates in one direction circumferentially, the rotation of the inner ring 237 is transmitted to the planetary carrier 231 via multiple planetary gears 229, causing the planetary carrier 231 to rotate in one direction circumferentially, and the output shaft 206 to rotate in one direction circumferentially. In this way, when the vehicle moves in reverse, the driving force from the electric motor 2 is transmitted to the output shaft 6.

[0092] Thus, according to the drive devices 101 and 201 of the second embodiment, the structure can be simplified, the increase in installation space can be suppressed, and the weight can be reduced, similar to the first embodiment.

[0093] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate. For example, the present invention can also be applied to a vehicle that uses an engine as a power source. [Explanation of Symbols]

[0094] 1, 11, 101, 201 Drive unit 2 Electric motor 3. Wet clutch 4, 104, 204 input axes 6, 106, 206 output shafts 7 Clutch Case 8, 108, 208 Two-way clutch 12 Frictional engagement device 14 First linking gear 16. Second connecting gear 17, 117, 217 Low-speed transmission mechanism 18, 118, 218 High-speed transmission mechanism 24, 124, 224 outer rings 26 First claw member 28 Second claw member 30 Teeth 62 Clutch Hub 127, 227 Planetary gear mechanism 129, 229 Planetary Gear 131, 231 Planetary Carrier 133 Ring Gear 237 Inner circle 241 Sangiya

Claims

1. An input shaft on the drive source side; an output shaft that transmits the driving force of the driving source to a driving wheel side; a transmission mechanism that transmits the driving force from the input shaft to the output shaft, The transmission mechanism is a first transmission mechanism that reduces the rotation speed of the input shaft and transmits the reduced rotation speed to the output shaft; a second transmission mechanism capable of transmitting rotation of the input shaft to the output shaft at a speed faster than that of the first transmission mechanism, the first transmission mechanism includes a two-way clutch that can selectively transmit to the output shaft rotation of the input shaft in a direction in which the vehicle moves forward and rotation in a direction in which the vehicle moves backward, The drive device according to claim 1, wherein the second speed change mechanism includes a clutch mechanism capable of transmitting the forward rotation of the input shaft to the output shaft by frictional engagement.

2. The input shaft and the output shaft are arranged in parallel, the first transmission mechanism includes a first gear provided on the input shaft and rotating integrally with the input shaft, and a second gear provided on the output shaft and meshing with the first gear, the two-way clutch is provided between the second gear and the output shaft, the second transmission mechanism includes a third gear that is provided on the input shaft and rotates integrally with the input shaft, the third gear having a larger diameter than the first gear, and a fourth gear that is provided on the output shaft and meshes with the third gear, the fourth gear having a smaller diameter than the second gear, 2. The drive device according to claim 1, wherein the clutch mechanism is provided between the fourth gear and the output shaft.

3. The input shaft and the output shaft are arranged in parallel, the first transmission mechanism includes a first gear provided on the input shaft and rotating integrally with the input shaft, and a second gear provided on the output shaft and meshing with the first gear, the two-way clutch is provided between the second gear and the output shaft, the second transmission mechanism includes a third gear that is provided on the output shaft and rotates integrally with the output shaft, the third gear having a smaller diameter than the second gear, and a fourth gear that is provided on the input shaft and meshes with the third gear, the fourth gear having a larger diameter than the first gear, 2. The drive device according to claim 1, wherein the clutch mechanism is provided between the fourth gear and the input shaft.

4. A plurality of teeth are formed at predetermined intervals in the circumferential direction on the outer periphery of the output shaft, The two-way clutch is the gearbox includes an outer ring that rotates integrally with the second gear; a first pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward and engages with the toothed portion, locks the relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves backward; and a second pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward and engages with the toothed portion, locks the relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves forward, 4. The drive unit according to claim 2, wherein the second pawl members swing radially outward due to centrifugal force acting upon the rotation of the outer ring, and when the centrifugal force exceeds a predetermined magnitude, the second pawl members disengage from the tooth portion.

5. 5. The drive device according to claim 4, wherein when the second pawl member is in a disengaged state due to centrifugal force and the second transmission mechanism is engaged, the first pawl member is disengaged, disengaging the first transmission mechanism and causing the second transmission mechanism to become a main transmission mechanism for the driving force.

6. The input shaft and the output shaft are arranged on the same axis, the first transmission mechanism includes a planetary gear mechanism including a sun gear, a plurality of planetary gears meshing with the sun gear, a planetary carrier that rotatably supports the plurality of planetary gears, and a ring gear that meshes with the plurality of planetary gears; the output shaft is connected to the planetary carrier; the two-way clutch is provided between the input shaft and the planetary gear mechanism, 2. The drive unit according to claim 1, wherein the clutch mechanism is provided between the input shaft and the planetary carrier.

7. the input shaft constitutes an inner ring of the two-way clutch, A plurality of teeth are formed at predetermined intervals in the circumferential direction on the outer periphery of the input shaft, the sun gear constitutes an outer ring of the two-way clutch, 7. The drive device according to claim 6, wherein the two-way clutch includes: a first pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward to engage with the tooth portion, locks relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves forward; and a second pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward to engage with the tooth portion, locks relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves backward.

8. The input shaft is formed in a cylindrical shape and constitutes an outer ring of the two-way clutch, the ring gear constitutes an inner ring of the two-way clutch, A plurality of teeth are formed at predetermined intervals in the circumferential direction on the outer periphery of the ring gear, 7. The drive device according to claim 6, wherein the two-way clutch includes: a first pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward to engage with the tooth portion, locks relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves backward; and a second pawl member that is held by the outer ring so as to be able to swing radially, and that, when it swings radially inward to engage with the tooth portion, locks relative rotation of the output shaft with respect to the outer ring in a direction in which the vehicle moves forward.

9. 9. The drive unit according to claim 7, wherein the second pawl members swing radially outward due to centrifugal force acting upon the rotation of the outer ring, and when the centrifugal force exceeds a predetermined magnitude, the second pawl members disengage from the tooth portion.

10. 10. The drive device according to claim 9, wherein when the second pawl member is in a disengaged state due to centrifugal force and the second transmission mechanism is engaged, the first pawl member is disengaged, disengaging the first transmission mechanism and causing the second transmission mechanism to become a main transmission mechanism for the driving force.

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