Drive unit

Abstract

To transmit forward rotation torque and reverse rotation torque which are output from an electric motor to an output unit via different gear rows.SOLUTION: A drive unit comprises an electric motor 2, a first gear row, a second gear row, a third gear row and a moving mechanism. The first gear row has a first drive gear, a first driven gear and a clutch member. The first driven gear is in a cylindrical shape. The clutch member is disposed so as to be movable in an axial direction within the first driven gear. Torque from the first driven gear is transmitted to the clutch member. The second gear row transmits torque from the first gear row to an output unit. The third gear row transmits torque from the first gear row to the output unit. The moving mechanism moves the clutch member toward the second drive gear in an axial direction when the electric motor makes forward rotation. The moving mechanism moves the clutch member toward the third drive gear in the axial direction when the electric motor makes reverse rotation.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] A drive unit using an electric motor as a drive source has been proposed. The electric motor can output torque in both forward and reverse directions. A vehicle equipped with the drive unit moves forward when the electric motor rotates forward, and moves backward when the electric motor rotates reversely. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-172974 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for transmitting the forward torque and reverse torque output by an electric motor to an output unit via different gear trains, and an object of the present invention is to provide a drive unit capable of transmitting the forward torque and reverse torque output by an electric motor to an output unit via different gear trains. [Means for solving the problem]

[0005] A drive unit according to a first aspect is configured to drive an output unit. The drive unit includes an electric motor, a first gear train, a second gear train, a third gear train, and a moving mechanism. The electric motor is configured to rotate forward and backward. The first gear train has a first drive gear, a first driven gear, and a clutch member. The first drive gear is configured to transmit torque from the electric motor. The first driven gear is configured to transmit torque from the first drive gear. The first driven gear is cylindrical. The clutch member is arranged axially movably within the first driven gear. The clutch member is configured to transmit torque from the first driven gear. The second gear train has a second drive gear. The second gear train is configured to transmit torque from the first gear train to the output unit. The third gear train has a third drive gear. The third gear train is configured to transmit torque from the first gear train to the output unit. The moving mechanism is configured to axially move the clutch member toward and engage with the second drive gear when the electric motor rotates forward, and to axially move the clutch member toward and engage with the third drive gear when the electric motor rotates reverse.

[0006] According to this configuration, when the electric motor rotates in the forward direction, the movement mechanism moves the clutch member toward the second drive gear. As a result, the clutch member engages with the second drive gear, and torque from the first gear train is transmitted to the output unit via the second gear train. On the other hand, when the electric motor rotates in the reverse direction, the movement mechanism moves the clutch member toward the third drive gear. As a result, the clutch member engages with the third drive gear, and torque from the first gear train is transmitted to the output unit via the third gear train. In this way, the drive unit according to the first aspect can transmit the forward torque and reverse torque output by the electric motor to the output unit via different gear trains.

[0007] The drive unit according to the second aspect is the drive unit according to the first aspect, and is configured as follows: the clutch member is a helical gear. The clutch member is configured to mesh with a plurality of teeth formed on an inner peripheral surface of the first driven gear.

[0008] The drive unit according to a third aspect is the drive unit according to the first or second aspect, and is configured as follows: The third gear train has a larger reduction ratio than the second gear train.

[0009] A drive unit according to a fourth aspect is the drive unit according to any one of the first to third aspects, and is configured as follows: the second gear train has a support shaft extending in the axial direction from the second drive gear, and the clutch member is disposed on the support shaft so as to be rotatable relative to the support shaft and movable in the axial direction.

[0010] A drive unit according to a fifth aspect is the drive unit according to the fourth aspect, and is configured as follows: The third drive gear is disposed on the support shaft so as to be relatively rotatable.

[0011] A drive unit according to a sixth aspect is the drive unit according to any one of the first to fifth aspects, further comprising a rotational resistance imparting member. The rotational resistance imparting member is configured to impart rotational resistance to the clutch member.

[0012] The drive unit according to a seventh aspect is the drive unit according to the sixth aspect, and is configured as follows: When the electric motor is rotating and the output unit is stopped, the rotation resistance applying member is disposed between the stopping member that is stopped and the clutch member.

[0013] The drive unit according to an eighth aspect is the drive unit according to the sixth aspect, and is configured as follows. The second gear train has a support shaft extending in the axial direction from the second drive gear. The clutch member is disposed on the support shaft so as to be relatively rotatable and axially movable. The rotational resistance applying member is disposed between the clutch member and the support shaft.

[0014] A drive unit according to a ninth aspect is the drive unit according to any one of the first to eighth aspects, further comprising a restriction mechanism. The restriction mechanism is configured to restrict axial movement of the clutch member.

[0015] A drive unit according to a tenth aspect is the drive unit according to any one of the first to ninth aspects, and is configured as follows: The restriction mechanism has a centrifugal member that is rotatable integrally with the clutch member. The centrifugal member is configured to move radially outward by centrifugal force generated when the clutch member rotates, and to engage with the first driven gear.

[0016] The drive unit according to an eleventh aspect is the drive unit according to any one of the first to tenth aspects, and is configured as follows: The clutch member is configured to dog-engage with the second drive gear or the third drive gear.

[0017] A drive unit according to a twelfth aspect is the drive unit according to any one of the first to eleventh aspects, further comprising a torque converter. The torque converter is configured to amplify the torque of the forward rotation of the electric motor and transmit the amplified torque to the first gear train. Effect of the Invention

[0018] According to the present invention, forward rotation torque and reverse rotation torque output by the electric motor can be transmitted to the output unit via different gear trains. [Brief description of the drawings]

[0019] [Figure 1] FIG. [Diagram 2] FIG. 4 is an enlarged cross-sectional view showing the first to third gear trains. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 11 is a cross-sectional view of a drive unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, the drive unit according to this embodiment will be described with reference to the drawings. In the following description, unless otherwise specified, the axial direction is the direction in which the rotation axis O of the first driven gear 52 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.

[0021] <Drive unit> As shown in Fig. 1 and Fig. 2, the drive unit 100 includes an electric motor 2, a torque converter 3, a transmission shaft 4, a first gear train 5, a second gear train 6, a third gear train 7, a moving mechanism 8, a rotation resistance imparting member 9, and a regulating mechanism 11. The drive unit 100 is configured to drive an output unit 101. The output unit 101 includes a differential gear 102, a pair of drive shafts 103, and drive wheels (not shown). The output unit 101 may have only drive wheels. This drive unit 100 is mounted on, for example, an electric vehicle.

[0022] <Electric motor> The electric motor 2 has a motor case 21, a motor stator 22, and a rotor 23. The motor case 21 is fixed to a vehicle body frame or the like and is non-rotatable. The motor stator 22 and the rotor 23 are housed in the motor case 21. The motor stator 22 is fixed to the inner peripheral surface of the motor case 21. The rotor 23 is disposed inside the motor stator 22 in the radial direction. In other words, the electric motor 2 is a so-called inner rotor type motor. Note that the electric motor 2 may be an outer rotor type. The electric motor 2 is configured to rotate forward and reverse. When the electric motor 2 rotates forward, a vehicle equipped with the drive unit moves forward. When the electric motor 2 rotates reverse, the vehicle moves backward.

[0023] <Torque converter> The torque converter 3 is rotatably arranged. The rotation axis of the torque converter 3 substantially coincides with the rotation axis of the electric motor 2. The torque converter 3 is arranged at a distance from the electric motor 2 in the direction in which the rotation axis extends. The first to third gear trains 5 to 7 are arranged between the torque converter 3 and the electric motor 2. The electric motor 2, the third gear train 7, the first gear train 5, the second gear train 6, and the torque converter 3 are arranged in this order in the axial direction. The torque converter 3 receives torque from the electric motor 2. The torque converter 3 is configured to amplify the torque of the forward rotation of the electric motor 2 and transmit it to the first gear train 5.

[0024] The torque converter 3 includes a cover 31 , an impeller 32 , a turbine 33 , a stator 34 , a first one-way clutch 36 , and a centrifugal clutch 37 .

[0025] In the torque converter 3, an impeller 32 is disposed on the electric motor 2 side (left side in FIG. 1), and a cover 31 is disposed on the opposite side to the electric motor 2 (right side in FIG. 1). The torque converter 3 is housed in a torque converter case 30. A working fluid is supplied into the torque converter 3. The working fluid is, for example, hydraulic oil.

[0026] Torque from the electric motor 2 is input to the cover 31. The cover 31 is fixed to the first transmission shaft 41. The cover 31 rotates integrally with the first transmission shaft 41. The cover 31 is disposed so as to cover the turbine 33.

[0027] The impeller 32 rotates integrally with the cover 31. The impeller 32 is rotatably supported by the first fixed shaft 104 via a bearing member (not shown). The first fixed shaft 104 is non-rotatable.

[0028] The turbine 33 is disposed opposite the impeller 32. In particular, the turbine 33 faces the impeller 32 in the axial direction. Torque is transmitted to the turbine 33 from the impeller 32 via the working fluid.

[0029] A second transmission shaft is attached to the turbine 33. In detail, the second transmission shaft is spline-fitted to the turbine 33. The turbine 33 rotates integrally with the second transmission shaft .

[0030] The stator 34 is configured to straighten the flow of hydraulic oil returning from the turbine 33 to the impeller 32. The stator 34 is supported by the second fixed shaft 105 via a first one-way clutch 36. The stator 34 is disposed between the impeller 32 and the turbine 33 in the axial direction.

[0031] The first one-way clutch 36 is disposed between the second fixed shaft 105 and the stator 34. The first one-way clutch 36 is configured to enable the stator 34 to rotate in the forward direction. On the other hand, the first one-way clutch 36 disables the stator 34 to rotate in the reverse direction. The torque is amplified by the stator 34 and transmitted from the impeller 32 to the turbine 33.

[0032] The centrifugal clutch 37 is attached to the turbine 33 or the second transmission shaft 42. 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 centrifugal force generated by the rotation of the turbine 33. In detail, the centrifugal clutch 37 is configured to transmit torque from the cover 31 to the turbine 33 when the turbine 33 reaches or exceeds a predetermined rotation speed.

[0033] <Transmission shaft> The transmission shaft 4 is configured to transmit torque between the electric motor 2 and the first gear train 5. The transmission shaft 4 has a first transmission shaft 41 and a second transmission shaft .

[0034] The first transmission shaft 41 extends from the electric motor 2 toward the torque converter 3. In particular, the first transmission shaft 41 extends from the rotor 23 of the electric motor 2. The first transmission shaft 41 is rotatably arranged. The rotation axis of the first transmission shaft 41 is substantially collinear with the rotation axis of the electric motor 2 and the rotation axis of the torque converter 3.

[0035] The first transmission shaft 41 is configured to transmit torque between the electric motor 2 and the torque converter 3. The first transmission shaft 41 is connected to the impeller 32 of the torque converter 3. In detail, the first transmission shaft 41 is connected to the impeller 32 via the cover 31. A tip end of the first transmission shaft 41 is attached to the cover 31 of the torque converter 3.

[0036] The second transmission shaft 42 transmits torque between the torque converter 3 and the first gear train 5. The second transmission shaft 42 extends from the torque converter 3 toward the electric motor 2. The second transmission shaft 42 is rotatably arranged. The rotation axis of the second transmission shaft 42 is substantially collinear with the rotation axis of the electric motor 2 and the rotation axis of the torque converter 3. In addition, the rotation axis of the second transmission shaft 42 is also substantially collinear with the rotation axis of the first transmission shaft 41.

[0037] The second transmission shaft 42 is cylindrical. The first transmission shaft 41 extends inside the second transmission shaft 42. The first transmission shaft 41 is solid. One end (the right end in FIG. 1) of the second transmission shaft 42 is attached to the turbine 33 of the torque converter 3. The second transmission shaft 42 is rotatably disposed. The second transmission shaft 42 is rotatably supported, for example, by the case 40 or the like via a bearing member or the like.

[0038] A second one-way clutch 43 is disposed between the first transmission shaft 41 and the second transmission shaft 42. The second one-way clutch 43 rotates idly when the first transmission shaft 41 transmits the torque of the forward rotation of the electric motor 2. That is, when the vehicle moves forward, the second one-way clutch 43 does not transmit torque from the first transmission shaft 41 to the second transmission shaft 42. On the other hand, when the first transmission shaft 41 transmits the torque of the reverse rotation of the electric motor 2, the second one-way clutch 43 transmits the torque. That is, when the vehicle moves backward, the second one-way clutch 43 transmits the torque from the first transmission shaft 41 to the second transmission shaft 42.

[0039] <First gear train> 2, the first gear train 5 has a first drive gear 51, a first driven gear 52, and a clutch member 53. The first drive gear 51 is configured to transmit torque from the electric motor 2. The first drive gear 51 rotates integrally with the second transmission shaft 42. Specifically, the first drive gear 51 and the second transmission shaft 42 are configured as a single member.

[0040] The first driven gear 52 is disposed rotatably about the rotation axis O. The first driven gear 52 is immovable in the axial direction. Specifically, the first driven gear 52 is supported by the case 40 via a plurality of bearing members, the second drive gear 61, and the third drive gear 71. For this reason, the first driven gear 52 is immovable in the axial direction.

[0041] The first driven gear 52 is configured to transmit torque from the first drive gear 51. The first driven gear 52 is cylindrical. The first driven gear 52 has a plurality of teeth formed on both its outer circumferential surface and its inner circumferential surface. The first driven gear 52 meshes with the first drive gear 51 through the teeth formed on the outer circumferential surface of the first driven gear 52. The teeth formed on the inner circumferential surface of the first driven gear 52 constitute a helical gear. In other words, the first driven gear 52 is a helical internal gear.

[0042] The clutch member 53 is disposed within the first driven gear 52. The clutch member 53 is configured so that torque from the first driven gear 52 is transmitted to the clutch member 53. The clutch member 53 is disposed so as to be rotatable about the rotation axis O. The clutch member 53 rotates integrally with the first driven gear 52.

[0043] The clutch member is disposed so as to be movable in the axial direction. The clutch member 53 is cylindrical. The clutch member 53 has a plurality of teeth on its outer circumferential surface. Each of the teeth formed on the outer circumferential surface of the clutch member 53 meshes with each of the teeth formed on the inner circumferential surface of the first driven gear 52. The clutch member 53 is a helical gear configured to mesh with each of the teeth formed on the inner circumferential surface of the first driven gear.

[0044] Fig. 3 is a front view of clutch member 53. That is, Fig. 3 is a view of clutch member 53 viewed in a direction perpendicular to rotation axis O. Fig. 4 is a side view of the clutch member. That is, Fig. 4 is a view of clutch member 53 viewed in the axial direction.

[0045] 3 and 4, the clutch member 53 has a main body portion 531, a plurality of first fitting protrusions 532, and a plurality of second fitting protrusions 533. The main body portion 531 is cylindrical and has a plurality of teeth on its outer circumferential surface.

[0046] The first fitting protrusions 532 protrude in the axial direction from the main body portion 531. In detail, the first fitting protrusions 532 protrude from the main body portion 531 toward the second gear train 6. The first fitting protrusions 532 are disposed at intervals from one another in the circumferential direction.

[0047] The second fitting protrusions 533 protrude in the axial direction from the main body portion 531. In detail, the second fitting protrusions 533 protrude from the main body portion 531 toward the third gear train 7. That is, the second fitting protrusions 533 protrude on the opposite side from the first fitting protrusions 532. The second fitting protrusions 533 are disposed at intervals from one another in the circumferential direction.

[0048] <Second gear train> 2, the second gear train 6 is disposed adjacent to the first gear train 5 in the axial direction. The second gear train 6 is configured to transmit torque from the first gear train 5 to the output unit 101. The second gear train 6 is configured to transmit forward rotation torque of the electric motor 2. The second gear train 6 has a second drive gear 61, a second driven gear 62, and a support shaft 63.

[0049] The second drive gear 61 is rotatably supported by the case 40 or the like via a plurality of bearing members. The second drive gear 61 is immovable in the axial direction. The second drive gear 61 is arranged rotatably about a rotation axis O. The second drive gear 61 is arranged adjacent to the clutch member 53 in the axial direction.

[0050] The second drive gear 61 has a plurality of first fitting recesses 611 on a surface facing the clutch member 53. The plurality of first fitting recesses 611 are arranged at intervals from one another in the circumferential direction. The plurality of first fitting recesses 611 correspond to the plurality of first fitting protrusions 532. The plurality of first fitting protrusions 532 and the plurality of first fitting recesses 611 are fitted together, whereby the clutch member 53 is engaged with the second drive gear 61 of the second drive gear 61. As a result, the clutch member 53 and the second drive gear 61 rotate integrally, and the torque from the first gear train 5 is transmitted to the output unit 101 via the second gear train 6.

[0051] The support shaft 63 extends in the axial direction from the second drive gear 61. The support shaft 63 extends from the second drive gear 61 toward the third drive gear 71. The support shaft 63 rotates integrally with the second drive gear 61. The second drive gear 61 and the support shaft 63 are integrally formed by a single member.

[0052] The clutch member 53 is supported on the support shaft 63. Specifically, the support shaft 63 passes through the clutch member 53 in the axial direction. The clutch member 53 is rotatable relative to the support shaft 63. In addition, the clutch member 53 is movable on the support shaft 63 in the axial direction.

[0053] The second driven gear 62 is configured to transmit torque from the second drive gear 61. In detail, the second driven gear 62 meshes with the second drive gear 61. The second driven gear 62 transmits torque to the output unit 101.

[0054] <Third Gear Train> The third gear train 7 is disposed adjacent to the first gear train 5 in the axial direction. The third gear train 7 is disposed on the opposite side of the second gear train 6 with respect to the first gear train 5 in the axial direction. In other words, the first gear train 5 is disposed between the second gear train 6 and the third gear train 7 in the axial direction.

[0055] The third gear train 7 is configured to transmit the torque from the first gear train 5 to the output unit 101. The torque from the first gear train 5 is transmitted to the output unit 101 via either the second gear train 6 or the third gear train 7. The third gear train 7 is configured to transmit the torque of the electric motor 2 in the reverse rotation. The third gear train 7 has a larger reduction ratio than the second gear train 6.

[0056] The third gear train 7 has a third drive gear 71 and a third driven gear 72. The third drive gear 71 is supported on the support shaft 63 so as to be relatively rotatable. In detail, the support shaft 63 passes through the third drive gear 71 in the axial direction. The third drive gear 71 is rotatably supported by the case 40 or the like via a plurality of bearing members.

[0057] The third drive gear 71 is disposed to be rotatable about a rotation axis O. The third drive gear 71 is disposed adjacent to the clutch member 53 in the axial direction. The third drive gear 71 is In the axial direction, the clutch member 53 is disposed on the opposite side of the second drive gear 61. That is, in the axial direction, the clutch member 53 is disposed between the second drive gear 61 and the third drive gear 71. The third drive gear 71 is immovable in the axial direction. The third drive gear 71 has a smaller diameter and fewer teeth than the second drive gear 61.

[0058] The third drive gear 71 has a plurality of second fitting recesses 711 on a surface facing the clutch member 53. The plurality of second fitting recesses 711 are arranged at intervals from one another in the circumferential direction. The plurality of second fitting recesses 711 correspond to the plurality of second fitting protrusions 533. The plurality of second fitting protrusions 533 and the plurality of second fitting recesses 711 are fitted together, whereby the clutch member 53 is engaged with the third drive gear 71. As a result, the clutch member 53 and the third drive gear 71 rotate integrally, and the torque from the first gear train 5 is transmitted to the output unit 101 via the third gear train 7.

[0059] The third driven gear 72 is configured to receive torque from the third drive gear 71. In detail, the third driven gear 72 meshes with the third drive gear 71. The third driven gear 72 transmits the torque to the output unit 101.

[0060] <Movement mechanism> The moving mechanism 8 is configured to move the clutch member 53 in the axial direction. When the electric motor 2 rotates forward, the moving mechanism 8 moves the clutch member 53 in the axial direction toward the second drive gear 61. As a result, the clutch member 53 engages with the second drive gear 61 and rotates integrally with the second drive gear 61. In detail, the first fitting protrusion 532 of the clutch member 53 fits into the first fitting recess 611 of the second drive gear 61. That is, the clutch member 53 is dog-engaged with the second drive gear 61.

[0061] When the electric motor 2 rotates in the reverse direction, the movement mechanism 8 moves the clutch member 53 in the axial direction toward the third drive gear 71. As a result, the clutch member 53 engages with the third drive gear 71 and rotates integrally with the third drive gear 71. In detail, the second fitting protrusion 533 of the clutch member 53 fits into the second fitting recess 711 of the third drive gear 71. That is, the clutch member 53 is dog-engaged with the third drive gear 71.

[0062] This moving mechanism 8 is composed of a plurality of teeth formed on the inner peripheral surface of the first driven gear 52 and a plurality of teeth formed on the outer peripheral surface of the clutch member 53. Each tooth on the inner peripheral surface of the first driven gear 52 constitutes a helical internal gear. Each tooth on the outer peripheral surface of the clutch member 53 also constitutes a helical gear. In other words, the moving mechanism 8 is composed of a helical internal gear formed on the inner peripheral surface of the first driven gear 52 and a helical gear formed on the outer peripheral surface of the clutch member 53.

[0063] When torque is transmitted from each tooth formed on the inner circumferential surface of the first driven gear 52 to each tooth of the clutch member 53, a thrust force acts on the clutch member 53. When the electric motor 2 rotates forward, a thrust force acts on the clutch member 53 toward the second drive gear 61. As a result, the clutch member 53 moves axially toward the second drive gear 61, that is, moves to the right in FIG. 2, and engages with the second drive gear 61 to rotate integrally therewith. Then, the torque from the first gear train 5 is transmitted to the output unit 101 via the second gear train 6.

[0064] On the other hand, when the electric motor 2 rotates in the reverse direction, a thrust force acts on the clutch member 53 toward the third drive gear 71. As a result, the clutch member 53 moves axially toward the third drive gear 71, that is, moves to the left in FIG. 2, and engages with the third drive gear 71 to rotate integrally therewith. Then, the torque from the first gear train 5 is transmitted to the output unit 101 via the third gear train 7.

[0065] <Rotational resistance imparting member> The rotational resistance imparting member 9 is configured to impart rotational resistance to the clutch member 53. The rotational resistance imparting member 9 is disposed between the clutch member 53 and the support shaft 63. For example, the rotational resistance imparting member 9 is attached to the inner peripheral surface of the clutch member 53. This rotational resistance imparting member 9 imparts rotational resistance to the clutch member 53 when the clutch member 53 rotates relative to the support shaft 63, and as a result, a thrust force can be reliably applied to the clutch member 53. The rotational resistance imparting member 9 is made of a material having a higher friction coefficient than the clutch member 53. For example, the rotational resistance imparting member 9 is made of, for example, a resin, a friction material, or a leaf spring.

[0066] <Regulatory Mechanism> 5, the regulating mechanism 11 is configured to regulate the axial movement of the clutch member 53. The regulating mechanism 11 has a centrifugal member 111. The regulating mechanism 11 also has a first engaging recess 112 and a second engaging recess 113 formed on the inner circumferential surface of the first driven gear 52.

[0067] The first engagement recess 112 and the second engagement recess 113 are disposed with a gap between them in the axial direction. The first engagement recess 112 is formed at a position radially opposed to the centrifugal member 111 when the clutch member 53 is engaged with the second drive gear 61. The second engagement recess 113 is formed at a position radially opposed to the centrifugal member 111 when the clutch member 53 is engaged with the third drive gear 71.

[0068] The centrifugal member 111 is attached to the clutch member 53. The centrifugal member 111 is rotatable integrally with the clutch member 53. The centrifugal member 111 moves radially outward by centrifugal force generated when the clutch member 53 rotates.

[0069] The centrifugal member 111 moves radially outward to engage with the first driven gear 52. This restricts the axial movement of the clutch member 53. In detail, when the clutch member 53 rotates in a state where it is engaged with the second drive gear 61, the centrifugal member 111 engages with the first engagement recess 112. As a result, even if a thrust force acts on the clutch member 53 in a direction away from the second drive gear 61 due to deceleration or the like, the clutch member 53 can maintain a state where it is engaged with the second drive gear 61. Also, when the clutch member 53 rotates in a state where it is engaged with the third drive gear 71, the centrifugal member 111 engages with the second engagement recess 113. As a result, even if a thrust force acts on the clutch member 53 in a direction away from the third drive gear 71 due to deceleration or the like, the clutch member 53 can maintain a state where it is engaged with the third drive gear 71.

[0070] [Variations] Although the embodiment of the present invention has been described above, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention. Note that the following modifications can basically be applied simultaneously.

[0071] (a) In the above embodiment, the drive unit 100 has the torque converter 3, but the configuration of the drive unit 100 is not limited to this. For example, as shown in Fig. 6, the drive unit 100 does not need to have a torque converter. In this case, the transmission shaft 4 directly transmits torque from the electric motor 2 to the first gear train 5. The transmission shaft 4 directly transmits both the forward torque and the reverse torque of the electric motor 2 to the first gear train 5.

[0072] (b) In the above embodiment, the moving mechanism 8 is configured by helical gears formed on the inner circumferential surface of the first driven gear 52 and the outer circumferential surface of the clutch member 53, but the configuration of the moving mechanism 8 is not limited to this. For example, the moving mechanism 8 may be configured to move the clutch member 53 in the axial direction by hydraulic pressure or the like. In this case, spur gears instead of helical gears may be formed on the inner circumferential surface of the first driven gear 52 and the outer circumferential surface of the clutch member 53, respectively.

[0073] (c) In the above embodiment, the rotational resistance imparting member 9 was attached to the inner circumferential surface of the clutch member 53, but it may be attached to the outer circumferential surface of the support shaft 63. In this case, the rotational resistance imparting member 9 is made of a material having a higher friction coefficient than the support shaft 63.

[0074] Furthermore, although the rotational resistance imparting member 9 is disposed between the clutch member 53 and the support shaft 63, the rotational resistance imparting member 9 may be disposed at another position as long as it is disposed between the stopping member and the clutch member 53. The stopping member is a member that is stopped when the electric motor 2 is rotating and the output unit 101 is stopped. The support shaft 63 is also an example of a stopping member. Other examples of stopping members include the second drive gear 61 and the third drive gear 71. The drive unit 100 does not have to have the rotational resistance imparting member 9.

[0075] (d) In the above embodiment, the regulating mechanism 11 has the centrifugal member 111, but the configuration of the regulating mechanism 11 is not limited to this. For example, the regulating mechanism 11 may have a regulating member operated by hydraulic pressure, an actuator, or the like, instead of the centrifugal member 111. This regulating member is attached to the clutch member 53 in the same manner as the centrifugal member 111, and is engageable with the first engagement recess 112 and the second engagement recess 113. The centrifugal member 111 moves radially outward by centrifugal force, but the regulating member is moved radially by hydraulic pressure or an actuator.

[0076] (e) In the above embodiment, the support shaft 63 extends in the axial direction from the second drive gear 61, but the configuration of the support shaft 63 is not limited to this. For example, the support shaft 63 may extend from the third drive gear 71 toward the second drive gear 61. The clutch member 53 and the second drive gear 61 may be supported by the support shaft 63 so as to be rotatable relative to each other. [Explanation of symbols]

[0077] 2: Electric motor 3: Torque converter 5: First gear train 51: First drive gear 52: First driven gear 53: Clutch parts 6: 2nd gear train 61: Second drive gear 63: Support shaft 7: 3rd gear train 71: 3rd drive gear 8: Movement mechanism 9: Rotational resistance imparting member 11: Regulatory mechanisms 111: Centrifugal member 100: Drive unit 101: Output unit

Claims

1. a drive unit configured to drive an output unit, an electric motor configured for forward and reverse rotation; a first gear train including a first drive gear configured to receive torque from the electric motor, a cylindrical first driven gear configured to receive torque from the first drive gear, and a clutch member arranged axially movably within the first driven gear and configured to receive torque from the first driven gear; a second gear train having a second drive gear and configured to transmit torque from the first gear train to the output unit; a third gear train having a third drive gear and configured to transmit torque from the first gear train to the output unit; a movement mechanism configured to move the clutch member axially toward the second drive gear to engage with the second drive gear when the electric motor rotates in a forward direction, and to move the clutch member axially toward the third drive gear to engage with the third drive gear when the electric motor rotates in a reverse direction; A drive unit comprising:

2. the clutch member is a helical gear configured to mesh with a plurality of teeth formed on an inner circumferential surface of the first driven gear, 2. The drive unit according to claim 1.

3. The third gear train has a greater reduction ratio than the second gear train.

2. The drive unit according to claim 1.

4. the second gear train has a support shaft extending axially from the second drive gear, The clutch member is disposed on the support shaft so as to be relatively rotatable and axially movable.

2. The drive unit according to claim 1.

5. the third drive gear is disposed on the support shaft so as to be relatively rotatable; 5. A drive unit according to claim 4.

6. Further provided is a rotational resistance applying member configured to apply rotational resistance to the clutch member.

2. The drive unit according to claim 1.

7. the rotational resistance applying member is disposed between the stopping member, which is stationary, and the clutch member when the electric motor is rotating and the output unit is stationary; 7. A drive unit according to claim 6.

8. the second gear train has a support shaft extending axially from the second drive gear, the clutch member is disposed on the support shaft so as to be relatively rotatable and axially movable; The rotational resistance applying member is disposed between the clutch member and the support shaft.

7. A drive unit according to claim 6.

9. Further comprising a restricting mechanism configured to restrict axial movement of the clutch member.

2. The drive unit according to claim 1.

10. the restriction mechanism has a centrifugal member that is rotatable integrally with the clutch member, The centrifugal member is configured to move radially outward by centrifugal force generated when the clutch member rotates and to engage with the first driven gear.

10. A drive unit according to claim 9.

11. the clutch member is configured to be in dog engagement with the second drive gear or the third drive gear; 2. The drive unit according to claim 1.

12. a torque converter configured to amplify the torque of the forward rotation of the electric motor and transmit the amplified torque to the first gear train; 2. The drive unit according to claim 1.

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