Drive unit

Abstract

To achieve a plurality of forward moving modes without complicating a structure.SOLUTION: A torque converter amplifies torque of a first rotation direction. A first torque transmission path 6a transmits torque through a torque converter 3. A second torque transmission path 6b transmits torque without through the torque converter 3. A first gear train 41 outputs the torque directed in the first rotation direction as forward torque. A second gear train 42 outputs the torque directed in the first rotation direction as reverse torque. A controller 9 controls a motor 2 so as to rotate in the first rotation direction and at the same time, outputs torque via the first torque transmission path 6a and the first gear train 41 in a first forward moving mode, and controls the motor 2 so as to rotate in a second rotation direction and at the same time outputs the torque through the second torque transmission path 6b and the second gear train 42 in a second forward moving mode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a drive unit.

Background Art

[0002] An electric vehicle runs using a motor as a drive source. The electric vehicle moves forward by rotating the motor forward and moves backward by rotating the motor backward. In order to amplify the torque from the motor, an electric vehicle provided with a torque converter has been proposed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electric vehicle configured as described above, it is desirable to realize a plurality of forward modes without complicating the structure. Therefore, an object of the present invention is to provide a drive unit that can realize a plurality of forward modes without complicating the structure.

Means for Solving the Problems

[0005] A drive unit according to an aspect of the present invention is configured to drive a driving part. The drive unit includes a motor, a torque converter, a torque transmission member, a first and a second torque transmission path, a first and a second gear train, and a control unit. The motor is rotatable in a first rotation direction and is also configured to be rotatable in a second rotation direction opposite to the first rotation direction. The torque converter is configured to amplify the torque in the first rotation direction output by the motor. The torque transmission member has torque transmitted thereto from the torque converter. The first torque transmission path is configured to transmit the torque output by the motor to the torque transmission member via the torque converter. The second torque transmission path is configured to transmit the torque output by the motor to the torque transmission member without passing through the torque converter. The first and second gear trains are arranged downstream of the torque transmission member in the torque transmission path. The first gear train is configured to output the torque in the first rotation direction output by the motor as torque in the forward rotation direction. The second gear train is configured to output the torque in the first rotation direction output by the motor as torque in the reverse rotation direction. The control unit executes a first forward mode and a second forward mode. In the first forward mode, the control unit controls the motor to rotate in the first rotation direction and outputs torque via the first torque transmission path and the first gear train. In the second forward mode, the control unit controls the motor to rotate in the second rotation direction and outputs torque via the second torque transmission path and the second gear train.

[0006] According to this configuration, first, in the first forward mode, the control unit can cause the vehicle to move forward by rotating the motor in the first rotation direction and outputting torque via the first gear train for forward movement. Also, in the second forward mode, the control unit can also cause the vehicle to move forward by rotating the motor in the second rotation direction and outputting torque via the second gear train for reverse movement. That is, two forward modes can be realized by using the first gear train for forward movement and the second gear train for reverse movement. Therefore, a plurality of forward modes can be realized without providing a plurality of gear trains for forward movement, that is, without complicating the structure. Further, in the second forward mode in which the motor rotates in the second rotation direction, since torque is transmitted via the second torque transmission path that does not pass through the torque converter, a wasteful torque transmission path can be omitted and torque can be transmitted efficiently.

[0007] Preferably, the drive unit further includes a one-way clutch. The one-way clutch is disposed within the second torque transmission path. The one-way clutch is configured to transmit the torque in the second rotation direction output by the motor and block the torque in the first rotation direction output by the motor. According to this configuration, the torque in the first rotation direction is transmitted via the first torque transmission path by the one-way clutch, and the torque in the second rotation direction is transmitted via the second torque transmission path. Therefore, torque can be transmitted through an appropriate torque transmission path without controlling the torque transmission path by the control unit.

[0008] The drive unit may further include a control clutch instead of a one-way clutch. The control clutch is disposed within the second torque transmission path. The control clutch is configured to be controlled by a control unit. The control clutch is configured to be switchable between a transmission state in which torque output by the motor is transmitted and a cutoff state in which torque output by the motor is cut off. The control unit executes a third forward mode. In the third forward mode, the control unit controls the motor to rotate in the first rotation direction and outputs torque via the second torque transmission path and the first gear train. According to this configuration, a plurality of forward modes can be realized.

[0009] Preferably, the control unit executes a first reverse mode and a second reverse mode. In the first reverse mode, the control unit controls the motor to rotate in the first rotation direction and outputs torque via the first torque transmission path and the second gear train. In the second reverse mode, the control unit controls the motor to rotate in the second rotation direction and outputs torque via the second torque transmission path and the first gear train. According to this configuration, two reverse modes can be realized without providing a plurality of reverse gear trains.

[0010] Preferably, the first gear train has a larger gear ratio than the second gear train.

[0011] Preferably, the ratio (G1 / G2) of the gear ratio (G1) of the first gear train to the gear ratio (G2) of the second gear train is smaller than the torque ratio of the torque converter.

[0012] Preferably, the drive unit further includes a hydraulic pump. The hydraulic pump is configured to supply hydraulic pressure to the torque converter. The control unit stops the hydraulic pump when the motor is rotating in the second rotation direction.

Advantages of the Invention

[0013] According to the present invention, a plurality of forward modes can be realized without complicating the structure.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0015] Hereinafter, the drive unit according to the present embodiment will be described with reference to the drawings. FIG. 1 is a block diagram showing the torque transmission path of the drive unit, and FIG. 2 is a schematic diagram of the drive unit. In the following description, the axial direction is the direction in which the rotation axis O of the motor 2 and the torque converter 3 extends. The circumferential direction is the circumferential direction of a circle centered on the rotation axis O, and the radial direction is the radial direction of a circle centered on the rotation axis O. Also, in FIG. 1, the description of some members is omitted.

[0016] [Drive Unit 100] As shown in FIGS. 1 and 2, the drive unit 100 is configured to drive a drive wheel 101 (an example of a drive part). The drive unit 100 includes a motor 2, a torque converter 3, first and second torque transmission shafts 5a and 5b, first and second torque transmission paths 6a and 6b, a first one-way clutch 7, a torque output unit 4, a switching mechanism 8, and a control unit 9. This drive unit 100 is mounted on, for example, an electric vehicle. Note that the second torque transmission shaft 5b corresponds to the torque transmission member of the present invention. Also, the first one-way clutch 7 corresponds to the one-way clutch of the present invention.

[0017] <Motor> The motor 2 has a motor case 21, a stator 22, and a rotor 23. The motor 2 in the present embodiment is a so-called inner rotor type motor. The motor 2 is configured to be rotatable in a first rotation direction and a second rotation direction. Note that the second rotation direction is a rotation direction opposite to the first rotation direction.

[0018] The motor case 21 is fixed to a vehicle body frame or the like and is non-rotatable. The stator 22 is fixed to the inner peripheral surface of the motor case 21. The stator 22 is non-rotatable. The rotor 23 rotates around the rotation axis O. The rotor 23 is arranged inside the stator 22 in the radial direction.

[0019] <Torque Converter> The torque converter 3 is arranged at an interval from the motor 2 in the axial direction. A torque output unit 4 is arranged between the torque converter 3 and the motor 2. In the axial direction, the motor 2, the torque output unit 4, and the torque converter 3 are arranged in this order.

[0020] The rotation axis O of the torque converter 3 substantially coincides with the rotation axis O of the motor 2. Torque is transmitted from the motor 2 to the torque converter 3. And the torque converter 3 is configured to amplify the torque in the first rotation direction output by the motor 2. Note that the torque converter 3 does not amplify the torque in the second rotation direction of the motor 2. The torque converter 3 outputs the amplified torque to the torque output unit 4.

[0021] As shown in FIG. 3, the torque converter 3 has a cover 31, an impeller 32, a turbine 33, a stator 34, and a second one-way clutch 36. Further, the torque converter 3 further has a centrifugal clutch 37.

[0022] The torque converter 3 is arranged such that the impeller 32 faces the motor 2 side (the left side in FIG. 3), and the cover 31 faces the side opposite to the motor 2 (the right side in FIG. 3). This torque converter 3 is housed in the torque converter case 30. A working fluid is supplied into the torque converter 3. The working fluid is, for example, hydraulic oil.

[0023] Torque from the motor 2 is input to the cover 31. The cover 31 rotates by the torque from the motor 2. The cover 31 is fixed to the first torque transmission shaft 5a extending from the motor 2. For example, the cover 31 has a spline hole, and the first torque transmission shaft 5a is spline-fitted into the spline hole of the cover 31. Therefore, the cover 31 rotates integrally with the first torque transmission shaft 5a. The cover 31 is arranged so as to cover the turbine 33.

[0024] The cover 31 has a disk portion 311, a cylindrical portion 312, and a cover hub 313. The disk portion 311 has an opening at the center. The cylindrical portion 312 extends from the outer peripheral end of the disk portion 311 toward the motor 2 side. The disk portion 311 and the cylindrical portion 312 are formed of one member.

[0025] The cover hub 313 is fixed to the inner peripheral end of the disk portion 311. In this embodiment, the cover hub 313 is constituted by a separate member from the disk portion 311, but it may be constituted by one member with the disk portion 311.

[0026] The cover hub 313 has a first boss portion 313a, a first flange portion 313b, and a protruding portion 313c. The first boss portion 313a, the first flange portion 313b, and the protruding portion 313c are constituted by one member.

[0027] The first boss portion 313a is cylindrical and has a spline hole. The first torque transmission shaft 5a is spline-fitted to the first boss portion 313a. The first boss portion 313a is rotatably supported by the torque converter case 30 via a bearing member (not shown). Therefore, the first boss portion 313a extends axially from the first flange portion 313b to the side opposite to the motor 2.

[0028] The first flange portion 313b extends radially outward from the first boss portion 313a. Specifically, the first flange portion 313b extends radially outward from the end of the first boss portion 313a on the motor 2 side. The disk portion 311 is fixed to the outer peripheral end of the first flange portion 313b.

[0029] The protruding portion 313c extends axially from the first flange portion 313b. The protruding portion 313c extends toward the motor 2. The protruding portion 313c extends from the outer peripheral end of the first flange portion 313b. The protruding portion 313c is cylindrical. This protruding portion 313c has a plurality of through holes 313d. The working fluid is discharged from the torque converter 3 through the through holes 313d.

[0030] The impeller 32 rotates integrally with the cover 31. The impeller 32 is fixed to the cover 31. The impeller 32 has an impeller shell 321, a plurality of impeller blades 322, an impeller hub 323, and a plurality of supply channels 324.

[0031] The impeller shell 321 is fixed to the cover 31. A plurality of impeller blades 322 are attached to the inner surface of the impeller shell 321.

[0032] The impeller hub 323 is attached to the inner peripheral end of the impeller shell 321. In this embodiment, the impeller hub 323 is formed of one member with the impeller shell 321, but it may be formed of a separate member from the impeller shell 321.

[0033] The impeller hub 323 has a second boss portion 323a and a second flange portion 323b. The second boss portion 323a is cylindrical and extends in the axial direction. The second boss portion 323a is rotatably supported by a torque converter case 30 via a bearing member (not shown). It rotates. A fixed shaft 104 extends in the axial direction inside the second boss portion 323a. The fixed shaft 104 is cylindrical, and a second torque transmission shaft 5b extends in the axial direction inside the fixed shaft 104. The fixed shaft 104 extends from, for example, a transmission case 40 or a torque converter case 30. The fixed shaft 104 is non-rotatable.

[0034] The supply passage 324 is formed in the impeller hub 323. Specifically, the supply passage 324 is formed in the second flange portion 323b. The supply passage 324 extends radially outward from the inner peripheral surface of the impeller hub 323. And the supply passage 324 opens into the torus T. The torus T is a space surrounded by the impeller 32 and the turbine 33.

[0035] The supply passage 324 is closed in the axial direction. That is, the supply passage 324 is a through hole extending radially in the impeller hub 323. As shown in FIG. 4, the supply passage 324 extends radially. The supply passage 324 is inclined in the direction opposite to the rotation direction toward the radially outer side.

[0036] As shown in FIG. 3, the turbine 33 is arranged to face the impeller 32. Specifically, the turbine 33 faces the impeller 32 in the axial direction. Torque from the impeller 32 is transmitted to the turbine 33 via the working fluid.

[0037] The turbine 33 has a turbine shell 331, a plurality of turbine blades 332, and a turbine hub 333. The turbine blades 332 are fixed to the inner surface of the turbine shell 331.

[0038] The turbine hub 333 is fixed to the inner peripheral end of the turbine shell 331. For example, the turbine hub 333 is fixed to the turbine shell 331 by rivets. In this embodiment, the turbine hub 333 is constituted by a separate member from the turbine shell 331, but it may be constituted by one member with the turbine shell 331.

[0039] The second torque transmission shaft 5b is attached to the turbine hub 333. Specifically, the second torque transmission shaft 5b is spline-fitted to the turbine hub 333. The turbine hub 333 rotates integrally with the second torque transmission shaft 5b.

[0040] The turbine hub 333 has a third boss portion 333a and a third flange portion 333b. The third boss portion 333a and the third flange portion 333b are constituted by one member.

[0041] The third boss portion 333a is cylindrical and has a spline hole. The second torque transmission shaft 5b is spline-fitted to this third boss portion 333a. The third boss portion 333a extends axially from the third flange portion 333b to the side opposite to the motor 2. That is, the third boss portion 333a extends axially from the third flange portion 333b toward the cover hub 313.

[0042] The third boss portion 333a is arranged at a distance from the protruding portion 313c in the radial direction. That is, in the radial direction, the protruding portion 313c is arranged outside the third boss portion 333a. A first one-way clutch 7 is arranged between the third boss portion 333a and the protruding portion 313c. In a state where the first one-way clutch 7 is not present, the outer peripheral surface of the third boss portion 333a and the inner peripheral surface of the protruding portion 313c face each other.

[0043] A flow path through which the working fluid flows is formed between the tip of the third boss portion 333a and the cover hub 313. In the present embodiment, a plurality of cutout portions 333c are formed at the tip of the third boss portion 333a. The cutout portions 333c extend in the radial direction at the tip of the third boss portion 333a. The working fluid is discharged from the torque converter 3 through the cutout portions 333c and the through holes 313d.

[0044] The third flange portion 333b extends radially outward from the third boss portion 333a. Specifically, the third flange portion 333b extends radially outward from the end of the third boss portion 333a on the motor 2 side. A turbine shell 331 is fixed to the outer peripheral end of this third flange portion 333b by a rivet or the like.

[0045] The stator 34 is configured to rectify the working oil that returns from the turbine 33 to the impeller 32. The stator 34 is rotatable around the rotation axis O. For example, the stator 34 is supported by a fixed shaft 104 via a second one-way clutch 36. This stator 34 is arranged between the impeller 32 and the turbine 33 in the axial direction.

[0046] The stator 34 has a disk-shaped stator carrier 341 and a plurality of stator blades 342 attached to the outer peripheral surface thereof.

[0047] The second one-way clutch 36 is arranged between the fixed shaft 104 and the stator 34. The second one-way clutch 36 causes the stator 34 to Rotatable in the first rotation direction It is configured to be as such. On the other hand, the second one-way clutch 36 makes the stator 34 non-rotatable in the second rotational direction. The torque is amplified by this stator 34 and transmitted from the impeller 32 to the turbine 33.

[0048] The centrifugal clutch 37 is attached to the turbine 33. The centrifugal clutch 37 rotates integrally with the turbine 33. The centrifugal clutch 37 is configured to connect the cover 31 and the turbine 33 by the centrifugal force generated by the rotation of the turbine 33. Specifically, the centrifugal clutch 37 is configured to transmit torque from the cover 31 to the turbine 33 when the rotation speed of the turbine 33 reaches a predetermined rotation speed or more.

[0049] The centrifugal clutch 37 has a plurality of centrifugal members 371 and a friction material 372. The friction material 372 is attached to the outer peripheral surface of the centrifugal member 371. The centrifugal members 371 are arranged to be movable in the radial direction. Note that the centrifugal members 371 are arranged to be non-movable in the circumferential direction. For this reason, the centrifugal members 371 rotate together with the turbine 33 and move radially outward by the centrifugal force.

[0050] When the rotation speed of the turbine 33 reaches a predetermined rotation speed or more, in this centrifugal clutch 37, the centrifugal members 371 move radially outward, and the friction material 372 comes into frictional engagement with the inner peripheral surface of the cylindrical portion 312 of the cover 31. As a result, the centrifugal clutch 37 is turned on, and the torque from the cover 31 is transmitted to the turbine 33 via the centrifugal clutch 37. Note that even when the centrifugal clutch 37 is turned on, the working fluid can flow through the centrifugal clutch 37.

[0051] When the rotation speed of the turbine 33 is less than the predetermined rotation speed, the centrifugal members 371 move radially inward, and the frictional engagement between the friction material 372 and the inner peripheral surface of the cylindrical portion 312 of the cover 31 is released. As a result, the centrifugal clutch 37 is turned off, and the torque from the cover 31 is not transmitted to the turbine 33 via the centrifugal clutch 37. That is, the torque from the cover 31 is transmitted to the impeller 32 and then transmitted to the turbine 33 via the working fluid.

[0052] <First torque transmission shaft> As shown in FIGS. 2 and 3, the first torque transmission shaft 5a extends from the motor 2. Specifically, the first torque transmission shaft 5a extends from the rotor 23 of the motor 2. The first torque transmission shaft 5a extends toward the torque converter 3. The rotation axis of the first torque transmission shaft 5a is substantially collinear with the rotation axis of the motor 2 and the rotation axis of the torque converter 3.

[0053] The first torque transmission shaft 5a transmits the torque output by the motor 2 to the torque converter 3. The tip of the first torque transmission shaft 5a is attached to the cover hub 313 of the torque converter 3. The first torque transmission shaft 5a rotates integrally with the rotor 23 of the motor 2. The first torque transmission shaft 5a extends through the second torque transmission shaft 5b. The first torque transmission shaft 5a is solid. The first torque transmission shaft 5a has a communication passage 51 at its tip. The communication passage 51 extends in the axial direction. And the communication passage 51 communicates with an oil passage (not shown).

[0054] <Second torque transmission shaft> The second torque transmission shaft 5b receives torque from the torque converter 3. The second torque transmission shaft 5b outputs the torque from the torque converter 3 to the torque output portion 4. The second torque transmission shaft 5b extends axially from the torque converter 3 toward the motor 2.

[0055] The second torque transmission shaft 5b is cylindrical. The first torque transmission shaft 5a extends through this second torque transmission shaft 5b. One end (the right end in FIG. 3) of the second torque transmission shaft 5b is attached to the turbine 33 of the torque converter 3. On the other hand, the other end of the second torque transmission shaft 5b is rotatably supported by, for example, a bearing member in the transmission case 40.

[0056] <First and second torque transmission paths> As shown in FIG. 1, the first torque transmission path 6a is configured to transmit the torque output from the motor 2 to the second torque transmission shaft 5b via the torque converter 3. Specifically, in the first torque transmission path 6a, the torque is transmitted in the order of the first torque transmission shaft 5a, the torque converter 3, and the second torque transmission shaft 5b. More specifically, in the first torque transmission path 6a, the torque is transmitted in the order of the first torque transmission shaft 5a, the cover 31, the impeller 32, the turbine 33, and the second torque transmission shaft 5b (see FIG. 3).

[0057] The second torque transmission path 6b is configured to transmit the torque output from the motor 2 to the second torque transmission shaft 5b without passing through the torque converter 3. Specifically, in the second torque transmission path 6b, the torque is transmitted in the order of the first torque transmission shaft 5a, the first one-way clutch 7, and the second torque transmission shaft 5b. More specifically, in the second torque transmission path 6b, the torque is transmitted in the order of the first torque transmission shaft 5a, the cover 31, the turbine 33, and the second torque transmission shaft 5b (see FIG. 3). That is, the torque is transmitted without passing through the hydraulic fluid in the torque converter 3.

[0058] <The first one-way clutch> The first one-way clutch 7 is disposed within the second torque transmission path 6b. The first one-way clutch 7 is configured to transmit the torque in the second rotational direction output from the motor 2 while blocking the torque in the first rotational direction output from the motor 2. For this reason, when the motor 2 rotates in the second rotational direction, the torque is transmitted via the second torque transmission path 6b, and when the motor 2 rotates in the first rotational direction, the torque is transmitted via the first torque transmission path 6a instead of the second torque transmission path 6b. That is, when the motor 2 rotates in the first rotational direction, the torque is transmitted to the torque converter 3, and when the motor 2 rotates in the second rotational direction, the torque is transmitted to the second torque transmission shaft 5b without passing through the torque converter.

[0059] As shown in Fig. 3, specifically, the first one-way clutch 7 is disposed between the cover 31 and the turbine 33. When the torque in the first rotation direction of the motor 2 is input to the first one-way clutch 7, the first one-way clutch 7 enables the cover 31 to rotate relative to the turbine 33. Therefore, when the motor 2 rotates in the first rotation direction, the first one-way clutch 7 does not transmit torque from the cover 31 to the turbine 33. That is, the first one-way clutch 7 blocks the torque in the first rotation direction output by the motor 2, and the torque is transmitted via the first torque transmission path 6a without passing through the second torque transmission path 6b.

[0060] On the other hand, when the torque in the second rotation direction of the motor 2 is input to the first one-way clutch 7, the first one-way clutch 7 rotates the cover 31 integrally with the turbine 33. Therefore, when the motor 2 rotates in the second rotation direction, the first one-way clutch 7 transmits torque from the cover 31 to the turbine 33. That is, the torque in the second rotation direction output by the motor 2 is transmitted via the second torque transmission path 6b.

[0061] <Torque output unit> As shown in Fig. 2, the torque output unit 4 is disposed axially between the motor 2 and the torque converter 3. The torque output unit 4 is housed in the transmission case 40. In the torque transmission path, the torque output unit 4 is disposed downstream of the second torque transmission shaft 5b.

[0062] The torque output unit 4 outputs the torque from the second torque transmission shaft 5b to the drive wheel 101 side. Specifically, the torque output unit 4 outputs torque to the drive wheel 101 via the differential gear 109. As will be described later, the torque output unit 4 does not output torque in the neutral mode.

[0063] As shown in Fig. 5, the torque output unit 4 has a first gear train 41 and a second gear train 42. The torque output unit 4 outputs torque from either the first gear train 41 or the second gear train 42.

[0064] The first gear train 41 is configured to output the torque in the first rotation direction output by the motor 2 as the torque in the forward rotation direction. In other words, the first gear train 41 is configured to output the torque in the second rotation direction output by the motor 2 as the torque in the reverse rotation direction. Therefore, when the motor 2 is rotated in the first rotation direction and the torque is output to the drive wheels 101 via the first gear train 41, the vehicle moves forward. Also, when the motor 2 is rotated in the second rotation direction and the torque is output to the drive wheels 101 via the first gear train 41, the vehicle moves backward.

[0065] The second gear train 42 is configured to output the torque in the first rotation direction output by the motor 2 as the torque in the reverse rotation direction. In other words, the second gear train 42 is configured to output the torque in the second rotation direction output by the motor 2 as the torque in the forward rotation direction. Therefore, when the motor 2 is rotated in the first rotation direction and the torque is output to the drive wheels 101 via the second gear train 42, the vehicle moves backward. Also, when the motor 2 is rotated in the second rotation direction and the torque is output to the drive wheels 101 via the second gear train 42, the vehicle moves forward.

[0066] The first gear train 41 has a first gear 41a and a second gear 41b that mesh with each other. The first gear 41a is supported by the second torque transmission shaft 5b so as to be relatively rotatable. When the ring gear 82 of the switching mechanism 8 described later meshes, the first gear 41a rotates integrally with the second torque transmission shaft 5b.

[0067] The second gear 41b is supported by the drive shaft 43. The second gear 41b rotates integrally with the drive shaft 43. The second gear 41b outputs the torque from the first gear 41a to the drive shaft 43.

[0068] The second gear train 42 has a third gear 42a, a fourth gear 42b, and a fifth gear 42c. The second gear train 42 has one more gear than the first gear train 41. The third gear 42a is rotatably supported by the second torque transmission shaft 5b. When the ring gear 82 of the switching mechanism 8 described later meshes therewith, the third gear 42a rotates integrally with the second torque transmission shaft 5b.

[0069] The fourth gear 42b meshes with the third gear 42a. The fourth gear 42b is supported by a countershaft (not shown). The fourth gear 42b may rotate integrally with the countershaft or may rotate relative to the countershaft.

[0070] The fifth gear 42c meshes with the fourth gear 42b. The fifth gear 42c is supported by the drive shaft 43. The fifth gear 42c rotates integrally with the drive shaft 43. The fifth gear 42c outputs the torque from the third gear 42a to the drive shaft 43.

[0071] The gear ratio in the first gear train 41 is different from the gear ratio in the second gear train 42. Specifically, the gear ratio in the first gear train 41 is larger than the gear ratio in the second gear train 42. Preferably, the ratio (G1 / G2) of the gear ratio (G1) of the first gear train 41 to the gear ratio (G2) of the second gear train 42 is smaller than the torque ratio of the torque converter 3. The torque ratio of the torque converter 3 refers to the ratio (output torque / input torque) of the output torque output by the torque converter 3 to the input torque input to the torque converter 3.

[0072] The torque output unit 4 can be in any of a first output mode, a second output mode, and a neutral mode. The torque output unit 4 outputs torque via the first gear train 41 in the first output mode. Also, the torque output unit 4 outputs torque via the second gear train 42 in the second output mode. Further, the torque output unit 4 does not output the torque from the torque converter 3 in the neutral mode.

[0073] <Switching mechanism> The switching mechanism 8 is configured to switch the state of the torque output unit 4 to any one of a first output mode, a second output mode, and a neutral mode. The switching mechanism 8 has a clutch hub 81 and a ring gear 82. Note that the switching mechanism 8 may have a lever 83.

[0074] The clutch hub 81 is attached to the second torque transmission shaft 5b. The clutch hub 81 rotates integrally with the second torque transmission shaft 5b. The clutch hub 81 may be formed of one member with the second torque transmission shaft 5b or may be formed of separate members. The clutch hub 81 has a plurality of teeth on its outer peripheral surface.

[0075] The ring gear 82 has a plurality of teeth on its inner peripheral surface. The ring gear 82 is always engaged with the clutch hub 81 and rotates integrally with the clutch hub 81. That is, the ring gear 82 rotates integrally with the second torque transmission shaft 5b. The ring gear 82 is arranged to be movable in the axial direction.

[0076] As shown in FIG. 5, the ring gear 82 can be in a state of engaging with the clutch hub 81 and engaging with the first gear 41a. Specifically, the first gear 41a has a first cylindrical portion 411 that protrudes in the axial direction. The first cylindrical portion 411 has a plurality of teeth on its outer peripheral surface. And the ring gear 82 is engaged with the outer peripheral surface of this first cylindrical portion 411.

[0077] When the ring gear 82 engages with the clutch hub 81 and the first cylindrical portion 411 in this way, the torque output unit 4 enters the first output mode. That is, the torque from the second torque transmission shaft 5b is output via the first gear train 41.

[0078] As shown in FIG. 6, the ring gear 82 can engage with the clutch hub 81 and also engage with the third gear 42a. Specifically, the third gear 42a has a second cylindrical portion 421 that protrudes in the axial direction. The second cylindrical portion 421 has a plurality of teeth on its outer peripheral surface. And the ring gear 82 is engaged with the outer peripheral surface of this second cylindrical portion 421.

[0079] In this way, when the ring gear 82 engages with the clutch hub 81 and the second cylindrical portion 421, the torque output section 4 enters the second output mode. That is, the torque from the second torque transmission shaft 5b is output via the second gear train 42.

[0080] As shown in FIG. 7, the ring gear 82 can engage only with the clutch hub 81. In this way, when the ring gear 82 engages only with the clutch hub 81 and does not engage with both the first cylindrical portion 411 and the second cylindrical portion 421, the torque output section 4 enters the neutral mode. That is, the torque from the second torque transmission shaft 5b is not output to the driving wheel 101 side.

[0081] The switching mechanism 8 is controlled by the control unit 9. The ring gear 82 moves in the axial direction by being controlled by the control unit 9. As a result, the ring gear 82 engages with the clutch hub 81 and the first cylindrical portion 411, engages with the clutch hub 81 and the second cylindrical portion 421, or engages only with the clutch hub 81. Consequently, the switching mechanism 8 can switch the state of the torque output section 4 to any one of the first output mode, the second output mode, and the neutral mode.

[0082] When the switching mechanism 8 further has a lever 83, the lever 83 is connected to the ring gear 82. The lever 83 extends from the ring gear 82 to the outside of the transmission case 40. The lever 83 is operated by the driver. By operating the lever 83, the ring gear 82 can also be moved in the axial direction.

[0083] <Control Unit> As shown in FIG. 1, the control unit 9 is configured to control the motor 2 and the torque output unit 4. Note that the control unit 9 controls the torque output unit 4 by controlling the switching mechanism 8. The control unit 9 is constituted by, for example, a computer (such as a microcomputer) including a CPU (Central Processing Unit) and a ROM (Read Only Memory). Programs for performing various operations are stored in the ROM. The CPU executes the programs stored in the ROM.

[0084] The control unit 9 executes any one of a first forward mode, a second Forward mode, a first reverse mode, and a second reverse mode. When the control unit 9 executes the first or second forward mode, the drive unit 100 operates to move the vehicle forward. Also, when the control unit 9 executes the first or second reverse mode, the drive unit 100 operates to move the vehicle backward.

[0085] In the first forward mode, the control unit 9 controls the motor 2 to rotate in the first rotation direction. Also, in the first forward mode, the control unit 9 outputs torque via the first torque transmission path 6a and the first gear train 41. Specifically, the control unit 9 outputs torque via the first gear train 41 by controlling the switching mechanism 8.

[0086] Note that when the control unit 9 controls the motor 2 to rotate in the first rotation direction, the first one-way clutch 7 shuts off torque transmission. As a result, the torque in the first rotation direction output by the motor 2 is transmitted via the first torque transmission path 6a without passing through the second torque transmission path 6b.

[0087] In the second forward mode, the control unit 9 controls the motor 2 to rotate in the second rotation direction. Also, in the second forward mode, the control unit 9 outputs torque via the second torque transmission path 6b and the second gear train 42. Specifically, the control unit 9 outputs torque via the second gear train 42 by controlling the switching mechanism 8.

[0088] Note that by controlling the motor 2 so that the control unit 9 rotates in the second rotation direction, the first one-way clutch 7 transmits torque. As a result, the torque in the second rotation direction output by the motor 2 is transmitted via the second torque transmission path 6b.

[0089] In the first reverse mode, the control unit 9 controls the motor 2 to rotate in the first rotation direction. Also, in the first reverse mode, the control unit 9 outputs torque via the first torque transmission path 6a and the second gear train. Specifically, the control unit 9 outputs torque via the second gear train 42 by controlling the switching mechanism 8.

[0090] Note that by controlling the motor 2 so that the control unit 9 rotates in the first rotation direction, the first one-way clutch 7 shuts off torque transmission. As a result, the torque in the first rotation direction output by the motor 2 is transmitted via the first torque transmission path 6a without passing through the second torque transmission path 6b.

[0091] In the second reverse mode, the control unit 9 controls the motor 2 to rotate in the second rotation direction. Also, in the second reverse mode, the control unit 9 outputs torque via the second torque transmission path 6b and the first gear train 41. Specifically, the control unit 9 outputs torque via the first gear train 41 by controlling the switching mechanism 8.

[0092] Note that by controlling the motor 2 so that the control unit 9 rotates in the second rotation direction, the first one-way clutch 7 transmits torque. As a result, the torque in the second rotation direction output by the motor 2 is transmitted via the second torque transmission path 6b.

[0093] <Operation> In the drive unit 100 configured as described above, when the vehicle is moving forward, the control unit 9 executes the first forward mode or the second forward mode. Note that the driver may select the first forward mode or the second forward mode by operating, or the control unit 9 may select the first forward mode or the second forward mode based on driving conditions or the like. Table 1 shows the operations of each member in each forward and reverse mode. A to D of the drive characteristics in Table 1 correspond to each of the lines A to D in FIG. 8. Note that FIG. 8 is a graph showing the relationship between the vehicle speed and the driving force.

[0094]

Table 1

[0095] As shown in Table 1, when the control unit 9 executes the first forward mode, the motor 2 rotates in the first rotation direction. Since the first one-way clutch 7 blocks the torque output by this motor 2, the torque is transmitted via the first torque transmission path 6a. For this reason, the torque converter 3 operates and the torque is amplified. The torque amplified by the torque converter 3 is transmitted to the first gear train 41 via the second torque transmission shaft 5b. When the torque is transmitted from the first gear train 41 to the drive wheels 101 via the differential gear 109, the vehicle moves forward. Note that the drive characteristics of the drive unit 100 at this time are indicated by the line A in FIG. 8. As can be seen from the line A in FIG. 8, in the first forward mode, the drive unit 100 can output a high driving force at low speeds, so the first forward mode is a mode suitable for low speeds.

[0096] When the control unit 9 executes the second forward mode, the motor 2 rotates in the second rotation direction. Since the first one-way clutch 7 transmits the torque output by this motor 2, the torque is transmitted via the second torque transmission path 6b. That is, the torque is transmitted to the second torque transmission shaft 5b without passing through the torque converter 3. For this reason, the torque converter 3 does not operate and the torque is not amplified. The torque transmitted to the second torque transmission shaft 5b is transmitted to the drive wheels 101 via the second gear train 42 and the differential gear 109. As a result, the vehicle moves forward. Note that the driving characteristics of the drive unit 100 at this time are indicated by line B in FIG. 8. As can be seen from FIG. 8, when traveling at high speed, the second forward mode is more suitable than the first forward mode.

[0097] When the control unit 9 executes the first reverse mode, the motor 2 rotates in the first rotation direction. Since the first one-way clutch 7 blocks the torque output by this motor 2, the torque is transmitted via the first torque transmission path 6a. For this reason, the torque converter 3 operates and the torque is amplified. The torque amplified by the torque converter 3 is transmitted to the second gear train 42 via the second torque transmission shaft 5b. Torque is transmitted from the second gear train 42 to the drive wheels 101 via the differential gear 109, causing the vehicle to reverse. Note that the driving characteristics of the drive unit 100 at this time are indicated by line C in FIG. 8. As can be seen from line C in FIG. 8, in the first reverse mode, since a high driving force can be output at low speed, the first reverse mode is a mode suitable for low speeds. Note that, although not particularly limited, for example, line C overlaps line B in the high-speed region.

[0098] When the control unit 9 executes the second reverse mode, the motor 2 rotates in the second rotation direction. Since the first one-way clutch 7 transmits the torque output by this motor 2, the torque is transmitted via the second torque transmission path 6b. That is, the torque is transmitted to the second torque transmission shaft 5b without passing through the torque converter 3. Therefore, the torque converter 3 does not operate and the torque is not amplified. The torque transmitted to the second torque transmission shaft 5b is transmitted to the drive wheels 101 via the first gear train 41 and the differential gear 109. As a result, the vehicle reverses. Note that the driving characteristics of the drive unit 100 at this time are indicated by line D in FIG. 8. As can be seen from FIG. 8, when high driving force is not required at low speeds, the second reverse mode is more suitable than the first reverse mode. Although not particularly limited, for example, line D overlaps with line A in the high-speed region.

[0099] [Modification Example] As described above, the embodiments of the present invention have been explained. However, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention.

[0100] Modification Example 1 The drive unit 100 may include a control clutch instead of the first one-way clutch 7. The control clutch is disposed within the second torque transmission path 6b and is configured to be controlled by the control unit 9.

[0101] The control clutch can be switched between a transmission state for transmitting the torque output by the motor 2 and a blocking state for blocking the torque output by the motor 2. By being controlled by the control unit 9, the control clutch switches between the transmission state and the blocking state. When the control unit 9 sets the control clutch to the transmission state, the torque is transmitted via the second torque transmission path 6b. Also, when the control unit 9 sets the control clutch to the blocking state, the torque is transmitted via the first torque transmission path 6a. By using this control clutch, as shown in Table 2 below, the control unit 9 can further execute two modes, namely, a third forward mode and a third reverse mode. Note that A to D of the driving characteristics in Table 2 correspond to respective lines A to D in FIG. 8.

[0102]

Table 2

[0103] The first and second forward modes and the first and second reverse modes are substantially the same as those in the above embodiment, and thus the description thereof is omitted.

[0104] In the third forward mode, the control unit 9 controls the motor 2 to rotate in the first rotation direction. Also, the control unit 9 outputs torque via the second torque transmission path 6b and the first gear train 41. Specifically, when the control unit 9 sets the control clutch to the transmission state, torque is output via the second torque transmission path 6b. Also, when the control unit 9 controls the switching mechanism 8, torque is output via the first gear train 41.

[0105] In the third reverse mode, the control unit 9 controls the motor 2 to rotate in the first rotation direction. Also, the control unit 9 outputs torque via the second torque transmission path 6b and the second gear train 42. Specifically, when the control unit 9 sets the control clutch to the transmission state, torque is output via the second torque transmission path 6b. Also, when the control unit 9 controls the switching mechanism 8, torque is output via the second gear train 42.

[0106] As shown in Table 2, when the control unit 9 executes the third forward mode, the motor 2 rotates in the first rotation direction. Since the control clutch transmits the torque output by this motor 2, the torque is transmitted via the second torque transmission path 6b. That is, the torque is transmitted to the second torque transmission shaft 5b without passing through the torque converter 3. For this reason, the torque converter 3 does not operate and the torque is not amplified. The torque transmitted to the second torque transmission shaft 5b is transmitted to the drive wheels 101 via the first gear train 41 and the differential gear 109. As a result, the vehicle moves forward. The driving characteristics of the drive unit 100 at this time are indicated by line D in FIG. 8.

[0107] When the control unit 9 executes the third reverse mode, the motor 2 rotates in the first rotation direction. Since the control clutch transmits the torque output by this motor 2, the torque is transmitted via the second torque transmission path 6b. That is, the torque is transmitted to the second torque transmission shaft 5b without passing through the torque converter 3. For this reason, the torque converter 3 does not operate and the torque is not amplified. The torque transmitted to the second torque transmission shaft 5b is transmitted to the drive wheels 101 via the second gear train 42 and the differential gear 109. As a result, the vehicle moves backward. The driving characteristics of the drive unit 100 at this time are indicated by line B in FIG. 8.

[0108] Modification Example 2 In the above embodiment, the impeller 32 has the supply flow path 324, but is not limited to this configuration. That is, the impeller 32 may not have the supply flow path 324. In this case, as shown in FIG. 9, the drive unit 100 may further include a hydraulic pump 12.

[0109] The hydraulic pump 12 is configured to supply hydraulic pressure to the torque converter 3. That is, the hydraulic pump 12 is configured to supply hydraulic oil into the torque converter 3. When the motor 2 is rotating in the second rotation direction, the control unit 9 stops the hydraulic pump 12.

[0110] Modification Example 3 In the above embodiment, the first gear train 41 is configured to have one less gear than the second gear train 42. However, the relationship between the number of gears in the first gear train 41 and the second gear train 42 is not limited to this. For example, the first gear train 41 may have one more gear than the second gear train 42.

Explanation of Signs

[0111] 2: Motor 3: Torque converter 5b: Second torque transmission shaft 6a: First torque transmission path 6b: Second torque transmission path 7: First one-way clutch 9: Control unit 12: Hydraulic pump 41: First gear train 42: Second gear train 100: Drive unit 101: Driving wheel

Claims

1. A drive unit for driving a drive section, comprising: a motor configured to be rotatable in a first rotation direction and a second rotation direction opposite to the first rotation direction; a torque converter configured to amplify the torque in the first rotation direction output by the motor; a torque transmission member to which torque is transmitted from the torque converter; a first torque transmission path configured to transmit the torque output by the motor to the torque transmission member via the torque converter; a second torque transmission path configured to transmit the torque output by the motor to the torque transmission member without passing through the torque converter; in the torque transmission path, a first gear train disposed downstream of the torque transmission member and configured to output the torque in the first rotation direction output by the motor as torque in the forward rotation direction; in the torque transmission path, a second gear train disposed downstream of the torque transmission member and configured to output the torque in the first rotation direction output by the motor as torque in the reverse rotation direction; a control unit that executes a first forward mode of controlling the motor to rotate in the first rotation direction and outputting torque via the first torque transmission path and the first gear train, and a second forward mode of controlling the motor to rotate in the second rotation direction and outputting torque via the second torque transmission path and the second gear train; The drive unit is provided with.

2. The drive unit according to claim 1, further comprising a one-way clutch disposed in the second torque transmission path and configured to transmit the torque in the second rotation direction output by the motor and block the torque in the first rotation direction output by the motor. The drive unit according to claim 1.

3. The drive unit according to claim 1, further comprising a control clutch disposed in the second torque transmission path and configured to be controlled by the control unit, the control clutch is configured to be switchable between a transmission state of transmitting the torque output by the motor and a blocking state of blocking the torque output by the motor, the control unit executes a third forward mode of controlling the motor to rotate in the first rotation direction and outputting torque via the second torque transmission path and the first gear train. The drive unit according to claim 1.

4. The control unit executes a first reverse mode in which the motor is controlled to rotate in the first rotation direction and torque is output via the first torque transmission path and the second gear train, and a second reverse mode in which the motor is controlled to rotate in the second rotation direction and torque is output via the second torque transmission path and the first gear train. The drive unit according to any one of claims 1 to 3.

5. The first gear train has a larger gear ratio than the second gear train. The drive unit according to any one of claims 1 to 4.

6. The ratio (G1 / G2) of the gear ratio (G1) of the first gear train to the gear ratio (G2) of the second gear train is smaller than the torque ratio of the torque converter. The drive unit according to any one of claims 1 to 5.

7. The drive unit further includes a hydraulic pump configured to supply hydraulic pressure to the torque converter. When the motor is rotating in the second rotation direction, the control unit stops the hydraulic pump. The drive unit according to any one of claims 1 to 6.

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