Drive unit and speed change gear

Abstract

To reduce energy consumption.SOLUTION: A planetary gear mechanism includes a sun gear, a planetary gear, a ring gear, and a planetary carrier. An input member connects one of the ring gear and the sun gear with an electric motor. An output member is connected to the planetary carrier. A first clutch connects the input member and the output member in such a manner that they can be cut off. A selectable one-way clutch is disposed between the other of the ring gear and the sun gear and a fixed member. In a first operation mode, the selectable one-way clutch allows rotation of the other of the ring gear and the sun gear in a forward rotation direction and inhibits rotation of the other of the ring gear and the sun gear in a reverse rotation direction. In a second operation mode, the selectable one-way clutch inhibits rotation of the other of the ring gear and the sun gear in the forward rotation direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] The transmission described in Patent Document 1 is configured to transmit power from an internal combustion engine to drive wheels by changing the rotational speed. Specifically, the transmission has a first clutch, a second clutch, and a planetary gear mechanism. The gear ratio of the transmission is changed by hydraulically switching the states of the first clutch and the second clutch. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-210149 Summary of the Invention [Problem to be solved by the invention]

[0004] When a transmission configured as described above is employed in a drive unit using an electric motor as a drive source, it is desirable to reduce energy consumption. Therefore, an object of the present invention is to reduce energy consumption. [Means for solving the problem]

[0005] A drive unit according to a first aspect includes an electric motor, a planetary gear mechanism, an input member, an output member, a first clutch, a fixed member, and a selectable one-way clutch. The planetary gear mechanism has a sun gear, planet gears, a ring gear, and a planet carrier. The input member connects one of the ring gear and the sun gear to the electric motor. The output member is connected to the planet carrier. The first clutch connects the input member and the output member in a disengageable manner. The fixed member is arranged to be non-rotatable. The selectable one-way clutch is arranged between the other of the ring gear and the sun gear and the fixed member. The selectable one-way clutch has a first operating mode and a second operating mode. In the first operating mode, the selectable one-way clutch is configured to permit rotation of the other of the ring gear and the sun gear in a forward rotation direction and to prevent rotation in a reverse rotation direction. In the second operating mode, the selectable one-way clutch is configured to prevent rotation of the other of the ring gear and the sun gear in a forward rotation direction.

[0006] With this configuration, when traveling forward, the selectable one-way clutch is set to the first operating mode, thereby preventing the rotation of the other of the ring gear and sun gear during low-speed traveling. Furthermore, when traveling backward, the selectable one-way clutch is set to the second operating mode, thereby preventing the rotation of the other of the ring gear and sun gear. Using the selectable one-way clutch in this way eliminates the need for hydraulic pressure to prevent the rotation of the other of the ring gear and sun gear, thereby reducing energy consumption.

[0007] A drive unit according to a second aspect is the drive unit according to the first aspect, configured as follows: The first clutch is a centrifugal clutch.

[0008] A drive unit according to a third aspect is the drive unit according to the second aspect, and is configured as follows: the input member is disposed radially outward from the output member; the first clutch has a centrifugal element and an engagement groove; the centrifugal element rotates integrally with the output member; the centrifugal element is disposed radially movable relative to the output member; the engagement groove is formed on the inner circumferential surface of the input member; and the engagement groove is configured to engage with the centrifugal element.

[0009] A drive unit according to a fourth aspect is the drive unit according to the third aspect, and is configured as follows: The first clutch further includes a magnet. The magnet is disposed radially inward of the centrifugal element and attracts the centrifugal element by magnetic force.

[0010] A drive unit according to a fifth aspect is the drive unit according to the third or fourth aspect, and is configured as follows: The engagement groove has a pair of inner wall surfaces that face each other in the circumferential direction, and at least one of the pair of inner wall surfaces is inclined radially inward so as to move away from the other inner wall surface.

[0011] A drive unit according to a sixth aspect is the drive unit according to any one of the first to fifth aspects, configured as follows: The input member has a first input portion, a second input portion, and an elastic member that elastically connects the first input portion and the second input portion.

[0012] A seventh aspect of the invention relates to a drive unit according to any one of the first to sixth aspects, and further includes a control unit. The control unit has a forward driving mode and a reverse driving mode. In the forward driving mode, the control unit rotates the electric motor in a forward rotation direction and sets the selectable one-way clutch to a first operating mode. In the reverse driving mode, the control unit rotates the electric motor in a reverse rotation direction and sets the selectable one-way clutch to a second operating mode.

[0013] A transmission according to an eighth aspect is configured to change the rotational speed of power from an electric motor. The transmission includes a planetary gear mechanism, an input member, an output member, a first clutch, a fixed member, and a selectable one-way clutch. The planetary gear mechanism has a sun gear, planet gears, a ring gear, and a planet carrier. The input member connects one of the ring gear and the sun gear to the electric motor. The output member is connected to the planet carrier. The first clutch connects the input member and the output member in a disengageable manner. The fixed member is arranged to be non-rotatable. The selectable one-way clutch is arranged between the other of the ring gear and the sun gear and the fixed member. The selectable one-way clutch has a first operating mode and a second operating mode. In the first operating mode, the selectable one-way clutch is configured to permit rotation of the other of the ring gear and the sun gear in a forward rotation direction and to prevent rotation in a reverse rotation direction. The selectable one-way clutch is configured to permit rotation of the other of the ring gear and the sun gear in a reverse rotational direction and prevent rotation in a forward rotational direction in the second operating mode. [Effects of the Invention]

[0014] According to the present invention, energy consumption can be reduced. [Brief explanation of the drawings]

[0015] [Figure 1] Block diagram of a drive unit. [Figure 2] Schematic diagram of a transmission. [Figure 3] FIG. [Figure 4] FIG. 4 is an enlarged view of the first clutch (disengaged state). [Figure 5] FIG. 4 is an enlarged view of the first clutch (engaged state). [Figure 6] FIG. 4 is a schematic diagram of a selectable one-way clutch in a first operating mode. [Figure 7] FIG. 5 is a schematic diagram of a selectable one-way clutch in a second operating mode. [Figure 8]4 is a flowchart showing a control method of the control unit. [Figure 9] FIG. 10 is a schematic diagram of a transmission according to a modified example. [Figure 10] 10 is a flowchart showing a control method of a control unit according to a modified example. [Figure 11] FIG. 10 is a schematic diagram of a transmission according to a modified example. [Figure 12] FIG. 10 is a schematic diagram of a transmission according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0016] The drive unit 100 according to this embodiment will be described below with reference to the drawings. In the following description, the axial direction refers to the direction in which the rotation axis O of the transmission 4 extends. The circumferential direction refers to the circumferential direction of a circle centered on the rotation axis O, and the radial direction refers to the radial direction of a circle centered on the rotation axis O. The forward rotation direction refers to the direction in which members that transmit torque, such as the electric motor 2 and the transmission 4, rotate when the vehicle on which the drive unit 100 is mounted is driven forward, and the reverse rotation direction refers to the direction in which members that transmit torque, such as the electric motor 2 and the transmission 4, rotate when the vehicle is driven backward.

[0017] [Drive unit] As shown in FIG. 1 , the drive unit 100 includes an electric motor 2, a reducer 3, a transmission 4, and a control unit 5. Torque output by the drive unit 100 is transmitted to drive wheels 102 via a differential gear 101. The drive unit 100 is mounted on, for example, an electric vehicle. Note that the drive unit 100 does not necessarily have to include the reducer 3.

[0018] [Electric motor] The electric motor 2 is configured to rotate in a forward rotation direction and a reverse rotation direction. When the vehicle is driven forward, the electric motor 2 rotates in the forward rotation direction. On the other hand, when the vehicle is driven backward, the electric motor 2 rotates in the reverse rotation direction.

[0019] [Reducer] The reducer 3 is disposed in the torque transmission path between the electric motor 2 and the transmission 4. The reducer 3 is configured to reduce the rotational speed of the power output by the electric motor 2 and output the power to the transmission 4. The reducer 3 has, for example, a plurality of gears (not shown).

[0020] [Transmission] The transmission 4 is configured to change the rotational speed of the power from the electric motor 2 and output it to the drive wheels 102. The transmission 4 is configured to change the gear ratio in stages. In this embodiment, the transmission 4 is configured to change the gear ratio in two stages.

[0021] As shown in FIG. 2, the transmission 4 has a planetary gear mechanism 41, an input member , an output member 43, a fixed housing 44 (an example of a fixed member), a first clutch 45, and a selectable one-way clutch .

[0022] [Planetary gear mechanism] 3 is a front view of the planetary gear mechanism 41. As shown in FIG. 3, the planetary gear mechanism 41 has a sun gear 411, a ring gear 412, a plurality of planet gears 413, and a planet carrier 414. The sun gear 411 is arranged to be rotatable around a rotation axis O. The ring gear 412 is annular. The ring gear 412 is an internal gear. The ring gear 412 is arranged to surround the sun gear 411. The ring gear 412 is arranged to be rotatable around the rotation axis O.

[0023] Each planetary gear 413 is disposed between the sun gear 411 and the ring gear 412 in the radial direction. Each planetary gear 413 is in mesh with the sun gear 411 and the ring gear 412. Each planetary gear 413 is disposed so as to be able to revolve around the rotation axis O. Each planetary gear 413 is also disposed so as to be able to rotate on its own axis. A planetary carrier 414 is attached to each planetary gear 413. The planetary carrier 414 is disposed so as to be rotatable around the rotation axis O.

[0024] The planetary gear mechanism 41 (more specifically, the ring gear 412 and the planet carrier 414) rotates in a forward rotation direction R1 when the drive unit 100 drives the vehicle forward. Also, the planetary gear mechanism 41 (more specifically, the ring gear 412 and the planet carrier 414) rotates in a reverse rotation direction R2 when the drive unit 100 drives the vehicle backward.

[0025] 2, the input member 42 connects the electric motor 2 and the ring gear 412. More specifically, the input member 42 connects the reducer 3 and the ring gear 412. The input member 42 rotates integrally with the ring gear 412. The input member 42 is configured to receive torque from the electric motor 2. The input member 42 is also configured to transmit the torque to the ring gear 412.

[0026] The input member 42 has a first input portion 421, a second input portion 422, and a plurality of elastic members 423. The first input portion 421 is configured to receive torque from the electric motor 2. The second input portion 422 is configured to transmit torque to the ring gear 412.

[0027] Each elastic member 423 elastically connects the first input portion 421 and the second input portion 422. That is, torque transmission between the first input portion 421 and the second input portion 422 is performed via each elastic member 423.

[0028] The output member 43 is connected to the planetary carrier 414. The output member 43 rotates integrally with the planetary carrier 414. The output member 43 is disposed rotatable about a rotation axis O. The output member 43 extends axially through the sun gear 411.

[0029] The output member 43 is configured to transmit the torque received from the planetary gear mechanism 41 to the drive wheels 102. In detail, the output member 43 is configured to transmit the torque to the differential gear 101.

[0030] [Fixed housing] The fixed housing 44 is arranged so as not to rotate. The fixed housing 44 is fixed to the frame of the vehicle or the like. The fixed housing 44 accommodates the planetary gear mechanism 41, the first clutch 45, and the selectable one-way clutch 46.

[0031] [First clutch] The first clutch 45 connects the input member 42 and the output member 43 in a disengageable manner. The first clutch 45 is configured to connect the input member 42 and the output member 43 (hereinafter referred to as the "connected state") and to disconnect the input member 42 and the output member 43 (hereinafter referred to as the "disengaged state"). The first clutch 45 is of a normally open type. That is, in a neutral state in which the drive unit 100 is not operating, the first clutch 45 is in a disengaged state.

[0032] When the first clutch 45 is in an engaged state, the input member 42 and the output member 43 are connected and rotate together. On the other hand, when the first clutch 45 is in a disengaged state, the input member 42 and the output member 43 are separated and become capable of relative rotation.

[0033] 4, the first clutch 45 is a centrifugal clutch. That is, the first clutch 45 is configured to engage the input member 42 and the output member 43 by receiving centrifugal force generated by the rotation of the output member 43. The first clutch 45 has a plurality of centrifugal elements 454, a plurality of engagement grooves 455, and a plurality of magnets 456.

[0034] More specifically, the input member 42 is disposed radially outward relative to the output member 43. Each engagement groove 455 is formed on the inner circumferential surface of the input member 42. Each engagement groove 455 faces radially inward. Each engagement groove 455 is disposed at intervals from one another in the circumferential direction. Each engagement groove 455 is configured to engage with a centrifugal element 454.

[0035] The pair of inner wall surfaces 455a, 455b that define the engagement groove 455 are inclined radially inward so as to move away from each other. The pair of inner wall surfaces 455a, 455b face each other in the circumferential direction. Note that at least one of the pair of inner wall surfaces 455a, 455b may be inclined.

[0036] The output member 43 has a plurality of accommodating portions 431. Each accommodating portion 431 opens radially outward. That is, each accommodating portion 431 is formed on the outer circumferential surface of the output member 43. The accommodating portions 431 are arranged at intervals from one another in the circumferential direction. The intervals between the accommodating portions 431 are preferably the same as the intervals between the engagement grooves 455.

[0037] Each centrifugal element 454 is housed in the housing portion 431. Each centrifugal element 454 rotates integrally with the output member 43. Each centrifugal element 454 is movable in the radial direction within the housing portion 431. Each centrifugal element 454 is magnetic.

[0038] Of the side surfaces 454a, 454b of each centrifugal element 454 facing in the circumferential direction, the portions that face the inner wall surfaces 455a, 455b when the centrifugal element 454 moves radially outward and engages with the engagement groove 455 are inclined along the inner wall surfaces 455a, 455b.

[0039] Each magnet 456 is disposed radially inward relative to each centrifugal element 454. Each magnet 456 is attached to the output member 43. Each magnet 456 is disposed radially inward relative to each housing portion 431. For example, each magnet 456 is embedded in the output member 43. Each magnet 456 is configured to attract the centrifugal element 454 by magnetic force.

[0040] With the first clutch 45 configured in this manner, when the rotational speed of the output member 43 becomes greater than a predetermined value, the centrifugal elements 454 move radially outward by centrifugal force and engage with the engagement grooves 455, as shown in Fig. 5. In other words, the first clutch 45 is in an engaged state. As a result, the input member 42 and the output member 43 rotate integrally.

[0041] On the other hand, when the rotation speed of the output member 43 falls below a predetermined value, as shown in Fig. 4, the centrifugal elements 454 move radially inward due to the inclination of the inner wall surfaces 455a, 455b and the magnetic force of the magnets 456, and the engagement between the centrifugal elements 454 and the engagement grooves 455 is released. In other words, the first clutch 45 is disengaged. As a result, the input member 42 and the output member 43 become rotatable relative to each other.

[0042] [Selectable one-way clutch] As shown in FIG. 2, the selectable one-way clutch 46 is disposed between the sun gear 411 and the fixed housing 44 .

[0043] 6 and 7, the selectable one-way clutch 46 has a first operation mode and a second operation mode. Fig. 6 is a schematic diagram of the selectable one-way clutch 46 in the first operation mode, and Fig. 7 is a schematic diagram of the selectable one-way clutch 46 in the second operation mode.

[0044] In a first operating mode, the selectable one-way clutch 46 is configured to permit rotation of the sun gear 411 in the forward rotation direction R1 and to prevent rotation of the sun gear 411 in the reverse rotation direction R2. In a second operating mode, the selectable one-way clutch 46 is configured to permit rotation of the sun gear 411 in the reverse rotation direction R2 and to prevent rotation of the sun gear 411 in the forward rotation direction R1.

[0045] The configuration of the selectable one-way clutch 46 is not particularly limited, but may be configured, for example, as follows: The selectable one-way clutch 46 has an outer ring 461, an inner ring 462, a first engaging member 463, a second engaging member 464, a first biasing member 465, a second biasing member 466, and a selection member 467.

[0046] The outer ring 461 is fixed to the sun gear 411. The outer ring 461 rotates integrally with the sun gear 411. The inner ring 462 is fixed to the fixed housing 44. The outer ring 461 and the inner ring 462 are rotatable relative to each other. Note that the inner ring 462 is fixed to the fixed housing 44 and therefore cannot rotate.

[0047] The first engaging member 463 and the second engaging member 464 are attached to the inner ring 462. In detail, a plurality of accommodating portions 468 are formed on the outer circumferential surface of the inner ring 462. The first engaging member 463 and the second engaging member 464 are accommodated in each accommodating portion 468.

[0048] The first biasing member 465 and the second biasing member 466 are configured to bias the first engagement member 463 and the second engagement member 464, respectively, toward the outer ring 461. In detail, the first biasing member 465 biases the end of the first engagement member 463 on the forward rotation direction R1 side toward the outer ring 461. The second biasing member 466 biases the end of the second engagement member 464 on the reverse rotation direction R2 side toward the outer ring. The first biasing member 465 and the second biasing member 466 are, for example, torsion springs.

[0049] A plurality of engagement grooves 469 are formed on the inner peripheral surface of the outer ring 461. An end of the first engagement member 463 on the forward rotation direction R1 side and an end of the second engagement member 464 on the reverse rotation direction R2 side engage with the engagement grooves 469.

[0050] As shown in Fig. 6, when the first engagement member 463 engages with the engagement groove 469, the outer ring 461 becomes rotatable in the forward rotation direction R1 but becomes unable to rotate in the reverse rotation direction R2. On the other hand, as shown in Fig. 7, when the second engagement member 464 engages with the engagement groove 469, the outer ring 461 becomes rotatable in the reverse rotation direction R2 but becomes unable to rotate in the forward rotation direction R1.

[0051] The selection member 467 is disposed so as to be unable to rotate together with the inner ring 462. The selection member 467 is rotatable relative to the inner ring 462 within a predetermined range. The selection member 467 is rotatable relative to the inner ring 462 between a position where the selection member 467 prevents the first engagement member 463 from moving toward the outer ring 461, and a position where the selection member 467 prevents the second engagement member 464 from moving toward the outer ring 461. The position of the selection member 467 is changed by an actuator 104 (see FIG. 2), such as an electric motor, for example.

[0052] When the selectable one-way clutch 46 is in the first operating mode, the selection member 467 prevents the second engagement member 464 from moving toward the outer ring 461, as shown in Fig. 6. As a result, only the first engagement member 463 engages with the engagement groove 469, and the outer ring 461 is rotatable in the forward rotation direction R1 but is unable to rotate in the reverse rotation direction R2. That is, in the first operating mode, the selectable one-way clutch 46 allows the sun gear 411 to rotate in the forward rotation direction R1 and prevents the sun gear 411 from rotating in the reverse rotation direction R2.

[0053] On the other hand, when the selectable one-way clutch 46 is in the second operation mode, the selection member 467 prevents the first engagement member 463 from moving toward the outer ring 461, as shown in Fig. 7. As a result, only the second engagement member 464 engages with the engagement groove 469, and the outer ring 461 is rotatable in the reverse rotation direction R2 but is unable to rotate in the forward rotation direction R1. That is, in the second operation mode, the selectable one-way clutch 46 allows the sun gear 411 to rotate in the reverse rotation direction R2 and prevents the sun gear 411 from rotating in the forward rotation direction R1.

[0054] [Control Unit] 1 and 2, the control unit 5 is configured to control the electric motor 2 and the selectable one-way clutch 46. Specifically, the control unit 5 is configured to control the position of the selection member 467 of the selectable one-way clutch 46 by controlling the actuator 104.

[0055] The control unit 5 is configured by, for example, a computer (for example, a microcomputer) equipped with a CPU (Central Processing Unit) and a ROM (Read Only Memory). The ROM stores programs for performing various calculations. The CPU executes the programs stored in the ROM.

[0056] The control unit 5 has a forward driving mode and a reverse driving mode. For example, as shown in Fig. 8, the control unit 5 determines whether or not a forward driving instruction has been received from the driver (step S1). If the control unit 5 determines that a forward driving instruction has been received (Yes in step S1), it executes the forward driving mode (step S2). On the other hand, if the control unit 5 determines that a forward driving instruction has not been received, i.e., that a reverse driving instruction has been received (No in step S1), it executes the reverse driving mode (step S3).

[0057] In the forward driving mode, the control unit 5 rotates the electric motor 2 in the forward rotation direction, and sets the selectable one-way clutch 46 to the first operating mode.

[0058] In the forward driving mode, when the rotational speed of the output member 43 is equal to or lower than a predetermined value, the first clutch 45 is disengaged, so that the ring gear 412 and the planetary carrier 414 rotate in the forward rotation direction R1 (clockwise in FIG. 3) while being rotatable relative to each other, as shown in FIG. 3. Since the selectable one-way clutch 46 is in the first operating mode, the sun gear 411 cannot rotate in the reverse rotation direction R2 (counterclockwise in FIG. 3) and is stationary.

[0059] As described above, the planetary gear mechanism 41 amplifies the torque from the input member 42 and transmits it to the output member 43. Furthermore, the planetary gear mechanism 41 reduces the rotational speed of the power from the input member 42 before transmitting it.

[0060] In the forward driving mode, when the rotational speed of the electric motor 2 increases and the rotational speed of the output member 43 exceeds a predetermined value, the first clutch 45 enters an engaged state, so that the ring gear 412 and the planetary carrier 414 rotate integrally in the forward rotation direction R1. Since the selectable one-way clutch 46 is in the first operating mode, the sun gear 411 rotates in the forward rotation direction R1.

[0061] As a result, the planetary gear mechanism 41 transmits the power from the input member 42 to the output member 43 without reducing the rotational speed.

[0062] In the reverse driving mode, the control unit 5 rotates the electric motor 2 in the reverse rotation direction, and the control unit 5 sets the selectable one-way clutch 46 to the second operating mode.

[0063] In the reverse drive mode, the rotational speed of the output member 43 is generally below a predetermined value, so the first clutch 45 is disengaged. Therefore, the ring gear 412 and the planetary carrier 414 rotate in the reverse rotation direction R2 while being rotatable relative to each other. Because the selectable one-way clutch 46 is in the second operating mode, the sun gear 411 cannot rotate in the forward rotation direction R1 and is stationary.

[0064] As described above, the planetary gear mechanism 41 amplifies the torque from the input member 42 and transmits it to the output member 43. Furthermore, the planetary gear mechanism 41 reduces the rotational speed of the power from the input member 42 before transmitting it.

[0065] As described above, the drive unit 100 does not require hydraulic pressure either when moving forward or backward, and therefore energy consumption can be reduced.

[0066] [Variations] Although the embodiments of the present invention have 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.

[0067] (a) As shown in FIG. 9, the first clutch 45 may be a multi-plate clutch. For example, the first clutch 45 has a plurality of first clutch discs 451, a plurality of second clutch discs 452, and a piston 453. The first clutch discs 451 and the second clutch discs 452 are arranged alternately in the axial direction. A friction material is arranged between the first clutch discs 451 and the second clutch discs 452. The friction material may be attached to the first clutch discs 451 or the second clutch discs 452.

[0068] The first clutch disc 451 is attached to the input member 42 so as to be movable in the axial direction. The first clutch disc 451 rotates integrally with the input member 42. The second clutch disc 452 is attached to the output member 43 so as to be movable in the axial direction. The second clutch disc 452 rotates integrally with the output member 43.

[0069] The piston 453 presses the first clutch disc 451 and the second clutch disc 452 so that the first clutch disc 451 and the second clutch disc 452 are frictionally engaged with each other.

[0070] The first clutch 45 is in a disengaged state by being biased by a biasing member 47. The biasing member 47 is, for example, a coil spring. The biasing member 47 presses the piston 453 in the axial direction so as to move it away from the first clutch disc 451 and the second clutch disc 452. Note that the first clutch 45 is brought into an engaged state by hydraulically moving the piston 453 in the axial direction against the biasing force of the biasing member 47.

[0071] In this case, the control unit 5 is configured to control the first clutch 45. In detail, the control unit 5 controls the first clutch 45 by controlling the hydraulic unit 103. The hydraulic unit 103 includes, for example, a hydraulic pump and a control valve. The hydraulic unit 103 supplies hydraulic pressure to the first clutch 45 via an oil passage P.

[0072] The control unit 5 has a forward low-speed traveling mode, a forward high-speed traveling mode, and a reverse traveling mode. For example, as shown in Fig. 10, the control unit 5 determines whether or not an instruction to travel forward has been received from the driver (step S11). If the control unit 5 determines that an instruction to travel forward has not been received, that is, that an instruction to travel backward has been received (No in step S11), the control unit 5 executes the reverse traveling mode (step S12).

[0073] On the other hand, when the control unit 5 determines that it has received a command to travel forward (Yes in step S11), it then determines whether the rotation speed of the output member 43 is equal to or less than a predetermined value (step S13). If the control unit 5 determines that the rotation speed of the output member 43 is equal to or less than the predetermined value (Yes in step S13), it executes the low-speed forward traveling mode (step S14). If the control unit 5 determines that the rotation speed of the output member 43 is not equal to or less than the predetermined value, that is, if the rotation speed of the output member 43 exceeds the predetermined value (No in step S13), it executes the high-speed forward traveling mode (step S15).

[0074] In the forward low-speed traveling mode, the control unit 5 rotates the electric motor 2 in the forward rotation direction. The control unit 5 then disengages the first clutch 45 and sets the selectable one-way clutch 46 to the first operating mode. Note that since the first clutch 45 is disengaged with no hydraulic pressure applied, the control unit 5 controls the hydraulic unit 103 to stop the supply of hydraulic pressure to the first clutch 45.

[0075] In the high-speed forward traveling mode, the control unit 5 rotates the electric motor 2 in the forward rotation direction. The control unit 5 then engages the first clutch 45 and places the selectable one-way clutch 46 in the first operating mode. In detail, the control unit 5 controls the hydraulic unit 103 to supply hydraulic pressure to the first clutch 45 and place the first clutch 45 in the engaged state.

[0076] In the reverse driving mode, the control unit 5 rotates the electric motor 2 in the reverse rotation direction, and then the control unit 5 disengages the first clutch 45 and puts the selectable one-way clutch 46 in the second operating mode.

[0077] When first clutch 45 is a multi-plate clutch, first clutch 45 may be of a normally closed type, as shown in Fig. 11. In other words, biasing member 47 may bias first clutch 45 so that first clutch 45 is in the connected state.

[0078] 12, the input member 42 may be connected to the sun gear 411. In this case, the selectable one-way clutch 46 is attached to the ring gear 412 instead of the sun gear 411. In other words, the selectable one-way clutch 46 is disposed between the ring gear 412 and the fixed housing 44.

[0079] In a first operating mode, the selectable one-way clutch 46 is configured to permit rotation of the ring gear 412 in the forward rotation direction R1 and to prevent rotation of the ring gear 412 in the reverse rotation direction R2. In a second operating mode, the selectable one-way clutch 46 is configured to permit rotation of the ring gear 412 in the reverse rotation direction R2 and to prevent rotation of the ring gear 412 in the forward rotation direction R1.

[0080] (c) The selectable one-way clutch 46 may not permit rotation in the reverse rotation direction in the second operating mode. That is, the selectable one-way clutch 46 may be configured to prevent rotation of the sun gear 411 in both the forward rotation direction R1 and the reverse rotation direction R2 in the second operating mode. [Explanation of symbols]

[0081] 2: Electric motor 4: Transmission 41: Planetary gear mechanism 411: Sun Gear 412: Ring gear 413: Planetary gear 414: Planet carrier 42: Input member 421: First input section 422: Second input section 423: Elastic member 43: Output member 44: Fixed housing 45: First clutch 454: Centrifugal element 455: Engagement groove 455a: Inner wall surface 455b: Inner wall 456: Magnet 46: Selectable one-way clutch 5: Control section 100: Drive unit

Claims

1. an electric motor; a planetary gear mechanism having a sun gear, planet gears, a ring gear, and a planet carrier; an input member connecting one of the ring gear and the sun gear to the electric motor; an output member connected to the planetary carrier; a first clutch that disconnectably connects the input member and the output member; a fixed member arranged non-rotatably; a selectable one-way clutch disposed between the other of the ring gear and the sun gear and the fixed member; Equipped with the selectable one-way clutch has a first operating mode and a second operating mode; the selectable one-way clutch is configured to permit rotation of the other of the ring gear and the sun gear in a forward rotation direction and to prevent rotation of the other of the ring gear and the sun gear in a reverse rotation direction in the first operating mode, and to prevent rotation of the other of the ring gear and the sun gear in the forward rotation direction in the second operating mode. Drive unit.

2. The first clutch is a centrifugal clutch.

2. The drive unit according to claim 1.

3. the input member is disposed radially outward relative to the output member, The first clutch is a centrifugal element that rotates integrally with the output member and is disposed so as to be movable in a radial direction relative to the output member; an engagement groove formed on an inner circumferential surface of the input member and configured to engage with the centrifugal element; having 3. The drive unit according to claim 2.

4. The first clutch further includes a magnet disposed radially inward of the centrifugal element and attracting the centrifugal element by magnetic force.

4. The drive unit according to claim 3.

5. The engagement groove has a pair of inner wall surfaces that face each other in the circumferential direction, At least one of the pair of inner wall surfaces is inclined radially inward so as to move away from the other inner wall surface.

4. The drive unit according to claim 3.

6. The input member has a first input portion, a second input portion, and an elastic member that elastically connects the first input portion and the second input portion.

2. The drive unit according to claim 1.

7. Further comprising a control unit having a forward driving mode and a reverse driving mode, The control unit In the forward driving mode, the electric motor is rotated in a forward rotation direction, and the selectable one-way clutch is set to the first operating mode; In the reverse driving mode, the electric motor is rotated in a reverse rotation direction, and the selectable one-way clutch is set to the second operating mode.

2. The drive unit according to claim 1.

8. 1. A transmission configured to vary the rotational speed of power from an electric motor, comprising: a planetary gear mechanism having a sun gear, planet gears, a ring gear, and a planet carrier; an input member connecting one of the ring gear and the sun gear to the electric motor; an output member connected to the planetary carrier; a first clutch that disconnectably connects the input member and the output member; a fixed member arranged non-rotatably; a selectable one-way clutch disposed between the other of the ring gear and the sun gear and the fixed member; Equipped with the selectable one-way clutch has a first operating mode and a second operating mode; the selectable one-way clutch is configured to permit rotation of the other of the ring gear and the sun gear in a forward rotation direction and to prevent rotation of the other of the ring gear and the sun gear in a reverse rotation direction in the first operating mode, and to prevent rotation of the other of the ring gear and the sun gear in the forward rotation direction in the second operating mode. Transmission.

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