Double clutch assembly for an electric drive of a vehicle and electric drive comprising same

Abstract

An electric drive device includes a housing, an electric motor, a transmission unit, and a dual clutch unit. The dual clutch unit includes a clutch housing, first and second clutch hubs, and first and second clutch plate assemblies. The transmission unit includes first and second output gears that are independently rotatable by a motor shaft. The clutch housing includes first and second gears configured to engage with the first and second output gears, respectively, to achieve different rotational driving forces.

Description

Technical Field

[0001] The present invention relates to an electric drive device for transmitting power to an electric motor, such as a motor. Background Technology

[0002] Electric motors, such as motors, are used as a power source to replace or add to a conventional internal combustion engine, and vehicles that use such motors as a power source are called electric vehicles or hybrid vehicles.

[0003] When a motor is used as a power source, a speed reduction device is needed to reduce the rotational speed of the motor. Since the motor's speed can be adjusted, electric drive devices implemented as single-stage speed reduction devices are sometimes used; however, electric drive devices capable of two-stage speed reduction for improved efficiency have also been employed. Such electric drive devices can be configured to achieve torque vectoring, enabling independent adjustment of the torque transmitted to the two drive wheels.

[0004] However, the problem with traditional electric drive systems lies in their large overall size and complex structure, as they use complex and bulky parts such as planetary gears to achieve deceleration and torque vectoring. Furthermore, improvements are needed in the structural aspects of the system to enhance ease of manufacture and reduce manufacturing costs by optimizing the arrangement of rotating shafts and bearings.

[0005] <Existing Literature>

[0006] - U.S. Patent No. 10,493,978 (December 3, 2019);

[0007] - U.S. Patent No. 10,753,405 (August 25, 2020). Summary of the Invention

[0008] [Technical Issues]

[0009] The problem to be solved by the present invention is to provide an electric drive device with two-stage deceleration and torque vector distribution functions that is simple in structure and easy to manufacture.

[0010] [Technical Solution]

[0011] An electric drive device according to one embodiment of the present invention includes: a housing; a motor including a motor shaft rotatably supported by the housing; a transmission unit for reducing the rotational speed of the rotational driving force of the motor shaft; and a dual-clutch unit configured to selectively rotate a first output shaft and a second output shaft. The dual-clutch unit includes: a clutch housing coupled to the transmission unit for being rotated by the transmission unit and rotatably mounted about a rotational axis; a first clutch hub and a second clutch hub, respectively coupled to a pair of output shafts for rotating the pair of output shafts and disposed adjacent to each other along the rotational axis within the clutch housing; a first clutch plate assembly operable to selectively achieve rotational constraint engagement between the clutch housing and the first clutch hub; and a second clutch plate assembly operable to selectively achieve rotational constraint engagement between the clutch housing and the second clutch hub. The transmission unit includes a first output gear and a second output gear that can be independently rotated by the motor shaft, and the clutch housing includes a first gear and a second gear configured to engage with the first output gear and the second output gear to achieve rotational driving forces at different speeds.

[0012] The clutch housing may include a first clutch housing and a second clutch housing, which are arranged adjacent to each other along the axis of rotation and coupled to each other to rotate together about the axis of rotation.

[0013] The first clutch housing and the second clutch housing can be coaxially coupled to each other through fastening members, and the first gear and the second gear are respectively disposed in the first clutch housing and the second clutch housing.

[0014] According to another embodiment of the invention, the electric drive device may further include a reaction plate inserted between the first clutch plate assembly and the second clutch plate assembly, which is used to support the first clutch plate assembly and the second clutch plate assembly respectively along the direction of the rotation axis.

[0015] The actuating plate can be installed to be inserted into an annular groove formed by the first clutch housing and the second clutch housing to prevent movement along the direction of rotation.

[0016] The first clutch hub and the second clutch hub can be supported relative to each other so that they can rotate relative to each other about a rotation axis via an axial bearing inserted between them.

[0017] The first gear and the second gear may respectively include a first ring gear and a second ring gear disposed on the outer peripheral surface of the clutch housing.

[0018] The clutch housing may include a first clutch housing and a second clutch housing, which are arranged adjacent to each other along a rotation axis and fastened to each other to rotate together about the rotation axis, wherein a first ring gear and a second ring gear may be respectively disposed on the outer peripheral surfaces of the first clutch housing and the second clutch housing.

[0019] An electric drive device according to another embodiment of the invention may further include: a first force transmission member movable along a rotation axis to press a first clutch plate assembly; a first piston configured to press the first force transmission member by moving along the rotation axis by hydraulic pressure; a second force transmission member movable along the rotation axis to press a second clutch plate assembly; and a second piston configured to press the second force transmission member by moving along the rotation axis by hydraulic pressure.

[0020] An electric drive device according to another embodiment of the present invention may further include a pair of clutch bearings for rotatably supporting the clutch housing. In this case, the pair of clutch bearings may be respectively disposed in the radial interior space of the first piston and the first force transmission member, and in the radial interior space of the second piston and the second force transmission member.

[0021] An electric drive device according to another embodiment of the invention may further include a piston housing having a space formed radially inward of the first and second pistons, wherein the first and second pistons are disposed. In this respect, the piston housing may include: a first axial extension extending along a rotation axis; a radial extension extending radially outward from the first axial extension; and a second axial extension extending along the rotation axis at a radial position further away from the rotation axis than the radial position of the first axial extension. The clutch housing may include a sleeve portion extending parallel to the rotation axis. The clutch bearing may be disposed in the space formed by the radial extension, the second axial extension, and the sleeve portion.

[0022] The clutch bearing can be a tapered roller bearing supported by a radial extension, a second axial extension, and a sleeve portion.

[0023] The first piston and the second piston may each include a main body portion facing the radial extension and a plurality of protrusions extending from the radially outer ends of the main body portion, respectively parallel to the axis of rotation. The radially inner ends of the protrusions and the radially inner ends of the first force transmission member and the second force transmission member may be formed to face the second axial extension.

[0024] According to another embodiment of the invention, the electric drive device may further include a return spring for returning the first piston and the second piston in a direction away from the force transmission member. The return spring may be configured to elastically support the main body portion relative to the radial extension in the direction of the rotation axis.

[0025] The first piston and the second piston may each include an annular body portion and a plurality of protrusions extending from the radially outer end of the body portion parallel to the axis of rotation.

[0026] An electric drive device according to another embodiment of the invention may further include a piston housing having a space formed radially inside the first piston and the second piston, wherein the first piston and the second piston are disposed. The piston housing may include: a first axial extension extending along a rotation axis; a radial extension formed by extending radially outward from the first axial extension; and a second axial extension extending along the rotation axis at a radial position further away from the rotation axis than the radial position of the first axial extension. The electric drive device may also include a return spring for resiliently supporting the first piston and the second piston to move relative to the radial extension away from the first force-transmitting member and the second force-transmitting member, respectively.

[0027] The first force transmission member and the second force transmission member may each have a disc-shaped main body and a plurality of protrusions extending from the radially inner end of the main body parallel to the axis of rotation, and the protrusions of the first piston and the second piston, as well as the protrusions of the first force transmission member and the second force transmission member, may be configured to at least partially face the outer peripheral surface of the second axial extension.

[0028] The clutch housing may include a sleeve portion extending parallel to the axis of rotation, and the sleeve portion and the second axial extension portion are configured to at least partially overlap in the direction of the axis of rotation. Furthermore, the electric drive may also include a clutch bearing disposed between the sleeve portion and the second axial extension portion to rotatably support the clutch housing.

[0029] According to one embodiment of the invention, a dual-clutch assembly is configured to selectively and variably rotate a pair of output shafts using a rotational driving force transmitted from a transmission unit of an electric drive device. It includes: a clutch housing coupled to the transmission unit for rotational drive by the transmission unit and rotatably mounted about a rotational axis; a first clutch hub and a second clutch hub, respectively coupled to the pair of output shafts for rotational drive of the pair of output shafts and disposed adjacent to each other within the clutch housing along the rotational axis; a first clutch plate assembly operable to selectively achieve rotationally constrained engagement between the clutch housing and the first clutch hub; and a second clutch plate assembly operable to selectively achieve rotationally constrained engagement between the clutch housing and the second clutch hub. The clutch housing has a plurality of gears configured to receive rotational driving forces of different rotational speeds from the transmission unit.

[0030] The clutch housing may include a first clutch housing and a second clutch housing, which are arranged adjacent to each other along the axis of rotation and coupled to each other to rotate together about the axis of rotation, and the multiple gears may include ring gears, which are formed on the outer peripheral surfaces of the first clutch housing and the second clutch housing to receive rotational driving forces of different speeds from the transmission unit respectively.

[0031] According to another embodiment of the invention, the dual-clutch assembly may further include: a first force transmission member movable along a rotation axis to press a first clutch plate assembly; a first piston configured to press the first force transmission member by moving along the rotation axis by hydraulic pressure; a second force transmission member movable along the rotation axis to press a second clutch plate assembly; and a second piston configured to press the second force transmission member by moving along the rotation axis by hydraulic pressure.

[0032] The first piston and the second piston may each include a main body portion facing the radial extension portion and a plurality of protrusions extending from the radially outer end portion of the main body portion, respectively parallel to the axis of rotation, and the radially inner end portions of the protrusions and the radially inner end portions of the first force transmission member and the second force transmission member may be formed to face the second axial extension portion.

[0033] The first piston and the second piston may each include an annular body portion and a plurality of protrusions extending from the radially outer end of the body portion parallel to the axis of rotation.

[0034] [Invention Effects]

[0035] According to the present invention, the dual-clutch assembly can rotate and drive two output shafts with a simple and easy-to-manufacture structure, and can increase the radial dimension as little as possible while ensuring sufficient hydraulic pressure area for stable operation of the piston. Attached Figure Description

[0036] Figure 1 A cross-sectional view of an electric drive device according to an embodiment of the present invention is shown.

[0037] Figure 2 A perspective view of the first reduction unit of an electric drive device according to an embodiment of the present invention is shown.

[0038] Figure 3 It is along Figure 2 The sectional view taken from line III-III.

[0039] Figure 4 An exploded perspective view of the first reduction unit of an electric drive device according to an embodiment of the present invention is shown.

[0040] Figure 5A perspective view of a first reduction unit, a second reduction unit, and a dual-clutch unit of an electric drive device according to an embodiment of the present invention is shown.

[0041] Figure 6 A perspective view of a dual-clutch unit of an electric drive device according to an embodiment of the present invention is shown.

[0042] Figure 7 It is along Figure 5 A sectional view taken from line VI-VI.

[0043] Figure 8 A partial cross-sectional view of the dual-clutch unit and housing of an electric drive device according to an embodiment of the present invention is shown.

[0044] Figure 9 An exploded perspective view of a dual-clutch unit of an electric drive device according to an embodiment of the present invention is shown. Detailed Implementation

[0045] In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily practice the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described.

[0046] The electric drive unit 1 can be configured to drive the drive shaft of a vehicle. The electric drive unit 1 can be used as a device for independently driving a vehicle, or it can be applied to a vehicle that uses an existing internal combustion engine as a power source and used as a device to drive the vehicle together with the internal combustion engine.

[0047] Figure 1 A cross-sectional view of an electric drive device according to an embodiment of the present invention is shown. Figure 1 This is a cross-sectional view of the electric drive device according to an embodiment of the present invention, cut along a V-shaped cutting line connecting the three rotation axes X1, X2, and X3. (Refer to...) Figure 1 According to an embodiment of the present invention, the electric drive device 1 includes a transmission unit 2 rotatably driven by an electric motor such as a motor 200, and a dual-clutch unit 3 rotatably driven by the transmission unit. The dual-clutch unit can be driven by actuators 4 and 5 respectively. The electric drive device 1 may also include a housing 6 accommodating the transmission unit 2 and the dual-clutch unit 3.

[0048] The motor may include a stator and a rotatable rotor. The rotor is configured to rotate by applying current supplied from the vehicle's battery, and the rotor is power-transmittedly connected to the motor shaft 7 to rotatably drive the motor shaft 7. Although not specified in the figures, the motor shaft 7 may be arranged coaxially with the motor and may be coupled to the motor's output element to be rotatably driven about a rotation axis X1 via the motor's output element. For example, the motor shaft 7 may be connected to the motor's output element via gear coupling, spline coupling, etc.

[0049] Although not in Figure 1 As shown in the diagram, however, housing 6 can also be... Figure 1 The right side of the housing 6 shown includes a housing for accommodating the motor, and the motor shaft 7 can be rotatably supported on the housing 6 by bearings. The housing 6 may include a first housing 11 and a second housing 12 fastened to each other, and the first housing 11 and the second housing 12 may be fastened to each other by separate fastening members or they may be fastened to each other by means such as welding.

[0050] The rotational motion of the motor shaft 7 is transmitted to the dual-clutch unit 3 via the transmission unit 2. That is, the rotational driving force of the motor is transmitted to the dual-clutch unit 3 through the motor shaft 7 and the transmission unit 2, and the dual-clutch unit 3 is configured to distribute the transmitted torque and deliver the distributed torque to the two output shafts 8 and 9. In addition, the output shafts 8 and 9 can be connected to the side shafts (not shown) connected to the drive wheels of the vehicle via constant velocity joints (not shown), respectively.

[0051] The motor shaft 7 can be constructed as a hollow shaft having a through hole 13 extending in the longitudinal direction, and can be supported on the housing 6 by bearings so as to be rotatable about the rotation axis X1. One of the two output shafts 8 and 9, the output shaft 8, can be arranged coaxially in the through hole 13 of the motor shaft 7. In this respect, the electric drive device 1 according to an embodiment of the present invention can be referred to as coaxial.

[0052] The drive gear 14 is mounted on the motor shaft 7 to rotate together with the motor shaft 7. The drive gear 14 extends in a ring shape in the circumferential direction of the motor shaft 7, thereby allowing the drive gear 14 to rotate together with the motor shaft 7 about the rotation axis X1.

[0053] According to an embodiment of the present invention, the transmission unit 2 includes a first reduction section 15 and a second reduction section 16. The first reduction section 15 and the second reduction section 16 are configured to reduce the rotational speed of the motor shaft 7 at different speeds and transmit it to the dual-clutch unit 3. The first reduction section 15 and the second reduction section 16 can achieve transmission by means of a gear mechanism that reduces the rotational speed via gear engagement.

[0054] The first reduction section 15 includes an input gear 17, a gear shift shaft 18, and an output gear 19. Similarly, the second reduction section 16 also includes an input gear 21, a gear shift shaft 22, and an output gear 23.

[0055] Input gears 17 and 21 engage with drive gear 14 and are rotatably driven by drive gear 14. Transmission shafts 18 and 22 are configured within housing 6 to rotate about rotation axes X2 and X3, respectively, extending parallel to the rotation axis X1 of motor shaft 7. Figure 1 As shown, the gear shift shafts 18 and 22 are inserted into the through-holes 23 of the input gear 17 and 24 of the input gear 21, arranged coaxially with the input gears 17 and 21. The gear shift shafts 18 and 22 are rotatably supported on the housing 6 by bearings such as tapered roller bearings 81, 82, 83, and 84. (Refer to...) Figure 1 and Figure 4 The tapered roller bearing 82 is supported on the housing 6 by a support ring 87. Needle roller bearings 25 and 26 are inserted between the input gears 17 and 21 and the transmission shafts 18 and 22 to allow relative rotation between the input gears 17 and 21 and the transmission shafts 18 and 22. (Refer to...) Figure 1 and Figure 4 The sleeve member 88 can be fastened to the gearbox shaft 18, and the needle roller bearing 25 is disposed between the sleeve member 88 and the input gear 17, so that the input gear 17 can be rotatably supported on the gearbox shaft 18.

[0056] Input gears 17 and 21 are configured to be selectively rotatably fixed to transmission shafts 18 and 22 via clutch units 27 and 28. That is, when clutch units 27 and 28 are in the operating state, i.e., in the state of transmitting rotational force, the rotation of input gears 17 and 21 is transmitted to transmission shafts 18 and 22 through clutch units 27 and 28; when clutch units 27 and 28 are in the state of not transmitting rotational force, input gears 17 and 21 rotate together with drive gear 14 without causing transmission shafts 18 and 22 to rotate.

[0057] The two clutch units 27 and 28, respectively disposed in the first reduction section 15 and the second reduction section 16, have the same structure and operate in the same manner. Clutch units 27 and 28 can be configured to be operated by hydraulic pressure. (Refer to...) Figures 1 to 3 Clutch units 27 and 28 respectively include clutch housings 29 and 33, clutch hubs 30 and 34, force transmission members 31 and 35, pistons 32 and 36, and clutch disc assemblies 42 and 43. Furthermore, clutch units 27 and 28 may also include axial bearings 37 and 39 disposed between the force transmission members 31 and 35 and the pistons 32 and 36 for rotatably supporting the force transmission members 31 and 35, and return springs 38 and 89 for returning the force transmission members 31 and 35.

[0058] Pistons 32 and 36 may have annular shapes and may be movably disposed in annular hydraulic chambers 40 and 41 formed in housing 6 in axial directions X2 and X3, where hydraulic pressure may be supplied.

[0059] The force transmission component 31 transmits the axial force generated by the movement of the piston 32 to the clutch disc assembly 42 disposed within the clutch housing 29. For example... Figure 4 As shown, the force transmission member 31 may include a main body 49 having the shape of an annular disk facing the piston 32 and a plurality of protrusions 50 axially protruding from the inner end of the main body 49.

[0060] Reference Figure 3 and Figure 4 The clutch disc assembly 42 includes a plurality of outer discs 44 and a plurality of inner discs 45 alternately arranged in the axial direction (i.e., in the direction of the rotation axis X2). The outer discs 44 are axially movable and circumferentially constrained to the clutch housing 29, and the inner discs 45 are axially movable and circumferentially constrained to the clutch hub 30. Similarly, the clutch disc assembly 43 of the second reduction section 16 also includes a plurality of outer discs and a plurality of inner discs, the outer discs being fastened to the clutch housing 33 and the inner discs being fastened to the clutch hub.

[0061] Clutch hubs 30 and 34 may be fixedly fastened to or integrally formed with input gear 17 to rotate together with input gear 17 about rotation axis X2, and clutch housings 29 and 30 may be fixedly fastened to transmission shaft 18 to rotate together with transmission shaft 18 about rotation axis X2.

[0062] Multiple protrusions 50 can be arranged at equal intervals in the circumferential direction on the surface of the main body 49, and each protrusion 50 penetrates the axial through-hole 52 formed in the input gear 17 to extend into the space where the clutch plate assembly 42 is located within the clutch housing 29. The force transmission member 31 is fastened to the input gear 17 by the protrusions 50 fastened to the axial through-hole 52 of the input gear 17 to rotate together with the input gear 17. At the same time, the force transmission member 31 is configured to move relative to the input gear 17 in the axial direction X2 to transmit the axial force of the piston 32 to the clutch plate assembly 42 disposed in the clutch housing 29. At this time, the protrusions 50 of the force transmission member 31 can be configured to act on the pressure plate 48 adjacent to the clutch plate assembly 42, which is axially movably disposed in the clutch housing 29. Meanwhile, the other side of the clutch plate assembly 42 can be supported on a support plate 47 supported in the axial direction by an axial bearing 46 supported on the clutch housing 29.

[0063] When hydraulic pressure is supplied to the hydraulic chamber 40, axial movement of the piston 32 occurs. Figure 3The piston 32 moves to the left, and the axial movement of the piston 32 causes the force transmission member 31 to move axially, thereby causing the protrusion 50 of the force transmission member 31 to press against the clutch disc assembly 42. When the clutch disc assembly 42 is pressed, the outer disc 44 and the inner disc 45 contact each other, causing the clutch hub 30 and the clutch housing 29 to rotate together about the rotation axis X2. Therefore, the transmission shaft 18 can rotate together with the input gear 17.

[0064] The return spring 38 causes the force transmission member 31 to return relative to the input gear 17 in a direction away from the clutch plate assembly 42. The return spring 38 may be a leaf spring that elastically supports the force transmission member 31 relative to the input gear 17. At this time, a retaining ring 51 for limiting the return movement of the force transmission member 31 can be fastened to the protrusion 50 of the force transmission member 31. Figure 1 and Figure 3 As shown, the retaining ring 51 of the protrusion 50 of the force transmission member 31 contacts the input gear 17, thereby preventing additional return operation of the force transmission member 31.

[0065] Output gears 19 and 23 are rotateably secured to transmission shafts 18 and 22, rotating together with them. Output gears 19 and 23 can be integrally formed as part of transmission shafts 18 and 22, or they can be formed separately and secured to transmission shafts 18 and 22. Output gears 19 and 23 can be ring gears formed circumferentially on the outer peripheral surfaces of transmission shafts 18 and 22, and can be integrally formed with transmission shafts 18 and 22. (See reference...) Figure 1 and Figure 5 Output gears 19 and 23 engage with two ring gears 54 and 55 respectively disposed in the clutch housing 56 of the dual-clutch unit 3 to drive the dual-clutch unit 3. Therefore, the clutch housing 56, which serves as the input element of the dual-clutch unit 3, can rotate by the rotation of the transmission shafts 18 and 22. At this time, the output gears 19 and 23 of the transmission shafts 18 and 22, and the ring gears 54 and 55 of the clutch unit 3 engaged therewith, may include helical teeth and can be configured to have a gear ratio for achieving the desired deceleration.

[0066] According to an embodiment of the present invention, it can be seen that two reduction ratios can be achieved by the transmission unit 2. The first reduction section 15 and the second reduction section 16 each have a transmission shaft 18 and 23 and two gear pairs. The first reduction section 15 has a first gear pair with a first reduction ratio through the engagement of the drive gear 14 of the motor shaft 7 and the input gear 17, and a second gear pair with a second reduction ratio through the engagement of the output gear 19 of the transmission shaft 18 and the ring gear 54 of the dual-clutch unit 3. At this time, the input gear 17 of the first reduction section 15 has more teeth than the drive gear 14 of the motor shaft 7 to achieve the first reduction ratio, and the ring gear 54 of the dual-clutch unit 3 also has more teeth than the output gear 19 of the transmission shaft 18 to achieve the second reduction ratio. Therefore, the first reduction section 15 achieves the final reduction ratio through a combination of the first and second reduction ratios. Similarly, the second reduction section 16 achieves a final gear ratio with two gear ratios: a first gear ratio achieved through the engagement of the drive gear 14 of the motor shaft 7 with the input gear 21, and a second gear ratio achieved through the engagement of the output gear 23 of the shift shaft 22 with the ring gear 55 of the dual-clutch unit 3. In this case, the input gear 17 of the first reduction section 15 and the input gear 21 of the second reduction section 16 can have the same number of teeth, and the output gear 19 of the first reduction section 15 can have fewer teeth than the output gear 23 of the second reduction section 16. Furthermore, the ring gear 54 of the dual-clutch unit 3, which engages with the output gear 19 of the first reduction section 15, can have more teeth than the ring gear 55 of the dual-clutch unit 3, which engages with the output gear 23 of the second reduction section 16. Due to this number of teeth, the first reduction section 15 has a larger reduction ratio than the second reduction section 16. The reduction ratio of the first reduction section 15 and the second reduction section 16 can be appropriately set as needed.

[0067] The dual-clutch unit 3 may include two clutches, each of which can operate independently. (See reference...) Figure 1 and Figures 5 to 7 The dual-clutch unit 3 includes a clutch housing 56 as an input element and two clutch hubs as output elements, namely, a first clutch hub 57 and a second clutch hub 58. The first clutch hub 57 is rotatably coupled to a first output shaft 8, and the first output shaft 8 transmits the applied torque to a side shaft (not shown) via a constant velocity joint (not shown). Similarly, the second clutch hub 58 can be rotatably coupled to a second output shaft 9. The two clutch hubs 57 and 58 can be rotatably supported relative to each other by means of an axial bearing 129 about a rotational axis X1. The axial bearing 129 has an annular shape and can be inserted between the clutch hubs 57 and 58 to rotatably support the clutch hubs 57 and 58 relative to each other.

[0068] The two ring gears 54 and 55 are formed on the outer peripheral surface of the clutch housing 56, and the clutch housing 56 receives rotational driving force from the transmission shafts 18 and 22 via these two ring gears 54 and 55. The clutch housing 56 is supported by clutch bearings 59 and 60 for rotational drive by the transmission shafts 18 and 22. The clutch bearings 59 and 60 may be implemented as tapered roller bearings that allow them to be introduced into the housing 6 while supporting axial forces.

[0069] Torque can be transmitted from the clutch housing 56 to the first clutch hub 57 and the second clutch hub 58 via two clutch plate assemblies (first clutch plate assembly 64 and second clutch plate assembly 65, respectively). Clutch plate assemblies 64 and 65 each include a plurality of outer plates 66 and a plurality of inner plates 67 alternately arranged in the axial direction (i.e., in the direction of the rotation axis X1). The outer plates 66 and inner plates 67 may each have an annular disc shape. The outer plates 66 are connected to the clutch housing 56 so as to be axially movable and circumferentially constrained (e.g., in a splined coupling manner), and the inner plates 67 are connected to the clutch hubs 57 and 58 so as to be axially movable and circumferentially constrained (e.g., in a splined coupling manner). The dual-clutch unit 3 can be arranged coaxially with respect to the motor, and the clutch housing 56 is rotatably supported within the housing 6 by means of clutch bearings 59 and 60 while being coaxial with the rotation axis X1 of the motor shaft 7. The first clutch hub 57 and the second clutch hub 58, which rotate together with the first output shaft 8 and the second output shaft 9 respectively, are rotatably supported by the clutch housing 56 by means of radial bearings 85 and 86 that are rotatable relative to the clutch housing 56.

[0070] The clutch housing 56 includes a first clutch housing 61 and a second clutch housing 62 arranged facing each other, and the first clutch housing 61 and the second clutch housing 62 are fastened to each other by fastening bolts 63 to rotate together about a rotation axis X1. The fastening bolts 63 extend in a direction parallel to the rotation axis X1 and may be multiple. Since the two clutch housings 61 and 62 are in close contact with each other in the axial direction and are fastened by the fastening bolts 63, the concentricity of the two clutch housings 61 and 62 can be improved.

[0071] The first clutch housing 61 and the second clutch housing 62 are arranged coaxially with the first output shaft 8 and the second output shaft 9. The first clutch housing 61 and the second clutch housing 62 are fastened to each other to form a generally cylindrical space, and the clutch hubs 57 and 58 and the clutch disc assemblies 64 and 65 are disposed in the space formed by the first clutch housing 61 and the second clutch housing 62.

[0072] like Figures 5 to 7As shown, the first clutch housing 61 and the second clutch housing 62 each include ring gears 54 and 55 that engage with the output gear 19 of the first reduction section 15 and the output gear 22 of the second reduction section 16, respectively. The two ring gears 54 and 55 are coaxially arranged with the rotation axis X1 and may have different dimensions and / or numbers of teeth. When the clutch unit 27 of the first reduction section 15 or the clutch unit 28 of the second reduction section 16 is in a power transmission state, rotational power is transmitted to one of the ring gears 54 and 55 in the two clutch housings 61 and 62, and the first clutch housing 61 and the second clutch housing 62, which are fastened together to rotate together, rotate together through the transmitted rotational power. When at least one of the two clutch plate assemblies 64 and 65 of the dual clutch unit 3 is in a power transmission state while the clutch housings 61 and 62 are rotating, rotational power is output through at least one of the first output shaft 8 and the second output shaft 9.

[0073] Reference Figure 1 and Figure 7 The first clutch housing 61 includes a clutch coupling portion 68 coupled to the outer clutch plate 66 and an end of the clutch fastening portion 68. Figure 7 The clutch coupling portion 68 and the cover portion 69 extend radially inward from the right end of the clutch coupling portion 69, and may also include a sleeve portion 70 extending axially from the inner end of the cover portion 69. The clutch coupling portion 68 and the cover portion 69 form a space in which the clutch plate assembly 64 is disposed, and the sleeve portion 70 forms a through hole through which the first output shaft 8 passes. The ring gear 54 that engages with the output gear 19 of the first reduction unit 15 may be formed on the outer peripheral surface of the clutch coupling portion 68. In addition, the second clutch housing 62 includes a clutch coupling portion 71 that couples with the outer clutch plate 66 and an end of the clutch coupling portion 71 ( Figure 7 The clutch coupling portion 71 and the cover portion 72 extend radially inward from the left end of the clutch housing 61, and may also include a sleeve 73 extending axially from the inner end of the cover portion 72. The clutch coupling portion 71 and the cover portion 72 form a space in which the clutch disc assembly 65 is disposed, and the sleeve portion 73 forms a through hole through which the second output shaft 9 passes. The sleeve portion 70 of the first clutch housing 61 and the sleeve portion 73 of the second clutch housing 62 are rotatably supported by clutch bearings 59 and 60, respectively.

[0074] The two clutches of the dual-clutch unit 3 can be operated independently by two actuators 4 and 5, respectively. For this purpose, the two actuators 4 and 5 can be independently controlled by a hydraulic circuit controlled by a control unit (not shown), thereby allowing the torque transmitted to the first clutch hub 57 via the second clutch plate assembly 65 to be independently and variablely set. This achieves a so-called torque vectoring distribution, which can change the torque of each drive wheel. The two actuators 4 and 5 are respectively arranged axially outside the first clutch housing 61 and the second clutch housing 62, and are supported in opposite directions along the axis of rotation X1 relative to the structure constituting the housing 6. Since the two actuators 4 and 5 are identical in structure and operation, only one actuator will be described below.

[0075] Force transmission members 101 and 102 transmit the axial force generated by actuators 4 and 5 to clutch disc assemblies 64 and 65 disposed within clutch housings 61 and 62. Force transmission members 101 and 102 are configured to move in the axial direction X1 via the axial force generated by actuators 4 and 5. (Refer to...) Figure 7 , Figure 8 and Figure 9 The force transmission members 101 and 102 include disc-shaped body portions 103 and 104 facing the cover portions 69 and 72 of the clutch housings 61 and 62, and a plurality of protrusions 105 and 106 projecting axially from the body portions 103 and 104. The plurality of protrusions 105 and 106 may be arranged at equal intervals in the circumferential direction on the surfaces of the body portions 103 and 104, and each of the protrusions 105 and 106 extends through axial through holes 107 and 108 formed on the cover portions 69 and 72 of the clutch housings 61 and 62 into the space containing the clutch disc assemblies 64 and 65 in the clutch housings 61 and 62. The force transmission members 101 and 102 are coupled to the clutch housings 61 and 62 by the protrusions 105 and 106 inserted into the axial through holes 107 and 108 of the clutch housings 61 and 62, so as to rotate together with the clutch housings 61 and 62. Furthermore, force transmission members 101 and 102 are configured to be axially movable relative to clutch housings 61 and 62 to transmit the axial force of actuators 4 and 5 located outside clutch housings 61 and 62 to clutch disc assemblies 64 and 65 located inside clutch housings 61 and 62.

[0076] The protrusions 105 and 106 of the force transmission members 101 and 102 are configured to act on the pressure plates 109 and 110 of adjacent clutch plate assemblies 64 and 65, which are axially movably disposed within clutch housings 61 and 62. Simultaneously, a reaction plate 111 is mounted in the clutch housing 56 and positioned between the two clutch plate assemblies 64 and 65 in a state that prevents axial movement. The reaction plate 111 may have the shape of an annular disc, and its radially outer end is inserted into an annular groove 112 formed between the first clutch housing 61 and the second clutch housing 62 to prevent their axial movement. The clutch plate assemblies 64 and 65, respectively disposed on both sides of the reaction plate 111, are supported axially by the reaction plate 111.

[0077] Actuators 4 and 5 can be implemented as hydraulic actuators, and each of actuators 4 and 5 includes pistons 113 and 114 movable in the axial direction X1 by hydraulic pressure. The piston, indicated by reference numeral 113, is pushed by hydraulic pressure to move along the axial direction X1. Figure 7 The piston moves to the left in the middle, and the piston, indicated by reference numeral 114, is pushed by hydraulic pressure along the axial direction X1. Figure 7 The pistons 113 and 114 can be integrally annular in shape and can be disposed in annular cylinder chambers 115 and 116 formed in the housing 6, as shown in the figure. Figure 1 As shown. Pistons 113 and 114 can be axially supported on retaining rings 117 and 118 fastened to the clutch housing 6 via support plates 119 and 120. Hydraulic passages 121 and 122 for supplying hydraulic force to the space between pistons 113 and 114 and support plates 119 and 120 can be formed in the clutch housing 6. Pistons 113 and 114 can be moved axially toward the clutch housings 61 and 62 in the X1 direction by the hydraulic pressure supplied to the space between support plates 119 and 120 and pistons 113 and 114.

[0078] Axial bearings 123 and 124 are inserted between pistons 113 and 114 and force transmission members 101 and 102 in an axially movable state, and the axial force of pistons 113 and 114 is transmitted to force transmission members 101 and 102 through axial bearings 123 and 124. As pistons 113 and 114 move toward clutch housings 61 and 62, axial bearings 123 and 124 and force transmission members 101 and 102 are pushed by pistons 113 and 114 to move together in the axial direction.

[0079] When actuators 4 and 5 are not in operation, i.e., when no hydraulic pressure is supplied to the space between pistons 113 and 114 and support plates 119 and 120, return springs 127 and 128 can be configured to return pistons 113 and 114 away from clutch housings 61 and 62. (Refer to...) Figure 1 and Figure 8 Return springs 127 and 128 elastically support pistons 113 and 114 relative to the clutch housing, and particularly relative to piston housings 131 and 132, to apply force to pistons 113 and 114 to push them away from clutch housings 61 and 62. When actuators 4 and 5 are not in operation, pistons 113 and 114 are disengaged from force transmission members 101 and 102 by the elastic restoring force of return springs 127 and 128, thereby not applying axial force to force transmission members 101 and 102. Figure 1 and Figure 8 As shown, the return springs 127 and 128 may be leaf springs that elastically support the pistons 113 and 114 relative to the piston housings 131 and 132 in a direction away from the clutch housings 61 and 62. Figure 7 and Figure 8 The diagram shows pistons 113 and 114 being pushed by the elastic restoring force of return springs 127 and 128 and in close contact with support plates 119 and 120. In this state, pistons 113 and 114 do not transmit axial force to force transmission members 101 and 102. Simultaneously, when hydraulic pressure is supplied to the space between support plates 119 and 120 and pistons 113 and 114, pistons 113 and 114 move toward clutch housings 61 and 62, compressing return springs 127 and 128 to move force transmission members 101 and 102. Therefore, force transmission members 101 and 102 press clutch plate assemblies 64 and 65, causing the clutch to operate.

[0080] Reference Figure 8 Clutch hubs 57 and 58 may include outer sleeves 141 and 142, inner sleeves 143 and 144, and connecting portions 145 and 146 connecting the outer sleeves 141 and 142 with the inner sleeves 143 and 144. The outer sleeves 141 and 142 may extend parallel to the axial direction X1 and have a hollow cylindrical shape, and clutch plate assemblies 64 and 65 may be coupled to the outer peripheral surfaces of the outer sleeves 141 and 142. The inner sleeves 143 and 144 may extend radially inward of the outer sleeves 141 and 142 parallel to the axial direction X1 and have a hollow cylindrical shape. (See reference...) Figure 1 and Figure 7Inner sleeves 143 and 144 form axial through holes into which output shafts 8 and 9 are inserted, and spline structures 171 and 172 for spline coupling with output shafts 8 and 9 can be formed on the inner circumference of inner sleeves 143 and 144. Clutch hubs 57 and 58 and output shafts 8 and 9 rotate together about a rotation axis X1 via spline coupling. Radial bearings 85 and 86 support the outer peripheral surfaces of inner sleeves 143 and 144 rotatably relative to clutch housings 61 and 62, thereby allowing clutch housings 61 and 62 to rotate relative to clutch hubs 57 and 58. Connecting portions 145 and 146 extend radially to connect one end of outer sleeves 141 and 142 and one end of inner sleeves 143 and 144. Connecting portions 145 and 146 of the two clutch hubs 57 and 58 are arranged to face each other, and axial bearings 129 are arranged to be supported by the two connecting portions 145 and 146 respectively. This allows the two clutch hubs 57 and 58 to rotate relative to each other and to rotate independently.

[0081] According to an embodiment of the invention, pistons 113 and 114 are configured to increase the effective area of ​​hydraulic pressure action without increasing the axial and radial length of the electric drive device. (Refer to...) Figure 8 and Figure 9 Pistons 113 and 114 have annular body portions 151 and 153 and multiple protrusions 152 and 154 extending radially outward from their outer edge regions parallel to the axial direction X1. The outer surfaces of the body portions 151 and 153 facing the support plates 119 and 120 in the axial direction are surfaces subjected to hydraulic pressure, and the protrusions 152 and 154 are parts that perform the function of transmitting axial force to the force transmission members 101 and 102 via bearings 123 and 124. Since the protrusions 152 and 154 protrude from the edge regions of the body portions 151 and 153, the effective area for hydraulic pressure application of the body portions 151 and 153 can be sufficiently obtained.

[0082] Reference Figure 8 The piston housings 131 and 132 include first axial extensions 161 and 162, radial extensions 163 and 164, and second axial extensions 165 and 166. The first axial extensions 161 and 162 and the second axial extensions 165 and 166 extend along the axial direction X1 at different radial positions. Figure 8 As shown, the second axial extensions 165 and 166 extend along the axial direction X1 at a radial position farther than the first axial extensions 161 and 162 (i.e., at a position farther away from the axial direction X1), and the radial extensions 163 and 164 extend in the radial direction to connect one end of the first axial extensions 161 and 162 and one end of the second axial extensions 165 and 166. (Refer to...) Figure 8The first axial extensions 161 and 162 face the radially inner ends of the main bodies 151 and 152 of pistons 113 and 114, and the radial extensions 163 and 164 face the axial sides of the main bodies 151 and 152 of pistons 113 and 114. Furthermore, the second axial extensions 165 and 166 face the radially inner ends of the protrusions 152 and 154 of pistons 113 and 114. Due to the shape and arrangement of pistons 113 and 114 and piston housings 131 and 132, the internal space in the radial direction of the second axial extensions 165 and 166 of piston housings 131 and 132 can be utilized, and in embodiments of the invention, such as... Figure 8 As shown, clutch bearings 59 and 60, which support clutch housings 161 and 162, are disposed in this space.

[0083] More specifically, the second axial extensions 165 and 166 of the piston housings 131 and 132 are radially positioned further outward than the sleeve portions 70 and 73 of the clutch housings 57 and 58. Simultaneously, the second axial extensions 165 and 166 of the housings 131 and 132 are configured to at least partially overlap with the sleeve portions 70 and 73 of the clutch housings 57 and 58 in the axial direction. As a result, annular bearing receiving spaces 181 and 182 are formed between the second axial extensions 165 and 166 of the piston housings 131 and 132 and the sleeve portions 70 and 73 of the clutch housings 57 and 58, and clutch bearings 59 and 60 are respectively disposed within the bearing receiving spaces 181 and 182. Therefore, as... Figure 7 As shown, clutch bearings 59 and 60 are disposed in the radial interior spaces of the protrusions 153 and 154 of pistons 113 and 114 and the force transmission members 101 and 102, thereby reducing the radial dimension of the entire system accordingly. In this case, clutch bearings 59 and 60 can be tapered roller bearings, and are radially supported by the sleeve portions 70 and 73 of clutch housings 57 and 58 and the second axial extensions 165 and 166 of piston housings 131 and 132, and axially supported by the cover portions 69 and 70 of clutch housings 57 and 58 and the radial extensions 163 and 164 of piston housings 131 and 132, respectively. With this structure, a sufficiently effective area for applying hydraulic force to pistons 113 and 114 can be obtained, and space for clutch bearings 59 and 60 to support clutch housings 57 and 58 can be obtained without significantly increasing the radial and axial dimensions of the entire device.

[0084] In addition, such as Figure 8As shown, the radially inner circumferential surfaces of the main bodies 103 and 104 of the force transmission members 101 and 102, and the radially inner circumferential surfaces of the axial bearings 123 and 124 inserted between the pistons 113 and 114 and the force transmission members 101 and 102, are configured to face the outer circumferential surfaces of the second axial extensions 165 and 166 of the piston housings 131 and 132. Due to the structure and arrangement of the piston housings 131 and 132, the pistons 113 and 114, the bearings 123 and 124, and the force transmission members 101 and 102, a compact structure is achieved.

[0085] While the invention has been described in conjunction with exemplary embodiments which are now considered practical, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0086] [Industrial Applicability]

[0087] This invention can be applied to electric drive systems for vehicles, and therefore has industrial applicability.

Claims

1. An electric drive device, comprising: case; An electric motor, comprising a motor shaft rotatably supported by the housing; A speed-changing unit is used to reduce the rotational speed of the motor shaft's driving force. as well as A dual-clutch unit configured to selectively drive a first output shaft and a second output shaft by rotation. The dual-clutch unit includes: A clutch housing coupled to the transmission unit for being rotatably driven by the transmission unit and rotatably mounted about a rotational axis; A first clutch hub and a second clutch hub, which are respectively coupled to the first output shaft and the second output shaft to rotatably drive the first output shaft and the second output shaft, and are disposed adjacent to each other in the clutch housing along the axis of rotation; A first clutch disc assembly operable to selectively achieve rotationally constrained engagement between the clutch housing and the first clutch hub; and The second clutch disc assembly is operable to selectively achieve rotationally constrained engagement between the clutch housing and the second clutch hub. The speed change unit includes a first output gear and a second output gear that can be independently rotated and driven by the motor shaft, and The clutch housing includes a first gear and a second gear configured to engage with the first output gear and the second output gear to achieve rotational driving force at different speeds.

2. The electric drive device according to claim 1, wherein, The clutch housing includes a first clutch housing and a second clutch housing, which are arranged adjacent to each other along the axis of rotation and coupled to each other to rotate together about the axis of rotation.

3. The electric drive device according to claim 2, wherein, The first clutch housing and the second clutch housing are coaxially coupled to each other by a fastening member, and the first gear and the second gear are respectively disposed in the first clutch housing and the second clutch housing.

4. The electric drive device according to claim 1, further comprising a reaction plate inserted between the first clutch plate assembly and the second clutch plate assembly for supporting the first clutch plate assembly and the second clutch plate assembly respectively along the direction of the rotation axis.

5. The electric drive device according to claim 4, wherein, The reaction plate is installed to be inserted into an annular groove formed by the first clutch housing and the second clutch housing to prevent movement along the direction of the rotation axis.

6. The electric drive device according to claim 1, wherein, The first clutch hub and the second clutch hub are supported relative to each other so that they can rotate relative to each other about the axis of rotation via an axial bearing inserted between them.

7. The electric drive device according to claim 1, wherein, The first gear and the second gear respectively include a first ring gear and a second ring gear disposed on the outer peripheral surface of the clutch housing.

8. The electric drive device according to claim 7, wherein, The clutch housing includes a first clutch housing and a second clutch housing, which are arranged adjacent to each other along the axis of rotation and fastened to each other to rotate together about the axis of rotation, wherein the first ring gear and the second ring gear are respectively disposed on the outer peripheral surfaces of the first clutch housing and the second clutch housing.

9. The electric drive device according to claim 1, further comprising: A first force transmission member is movable along the rotation axis to press the first clutch plate assembly; The first piston is configured to press the first force transmission member by moving along the axis of rotation under hydraulic pressure. A second force transmission member is movable along the rotation axis to press the second clutch plate assembly; as well as The second piston is configured to press the second force-transmitting member by moving along the axis of rotation under hydraulic pressure.

10. The electric drive device of claim 9, further comprising a pair of clutch bearings for rotatably supporting the clutch housing, wherein the pair of clutch bearings are respectively disposed in the radial interior space of the first piston and the first force transmission member and in the radial interior space of the second piston and the second force transmission member.

11. The electric drive device of claim 10, further comprising a piston housing, the piston housing forming a space disposed therein on the radially inner side of the first piston and the second piston. The piston housing includes: A first axial extension extending along the rotation axis; A radial extension portion extending radially outward from the first axial extension portion; as well as A second axial extension extending along the rotation axis at a radial position further away from the rotation axis than the radial position of the first axial extension. The clutch housing includes a sleeve portion extending parallel to the axis of rotation, and The clutch bearing is disposed in the space formed by the radial extension, the second axial extension and the sleeve portion.

12. The electric drive device according to claim 11, wherein, The clutch bearing is a tapered roller bearing supported by the radial extension, the second axial extension, and the sleeve portion, respectively.

13. The electric drive device according to claim 11, wherein, The first piston and the second piston each include a main body portion facing the radial extension portion and a plurality of protrusions extending from the radially outer end portion of the main body portion, respectively parallel to the axis of rotation, and wherein the radially inner end portions of the protrusions and the radially inner end portions of the first force transmission member and the second force transmission member are formed to face the second axial extension portion.

14. The electric drive device of claim 13, further comprising a return spring for returning the first piston and the second piston in a direction away from the force transmission member, wherein the return spring is configured to elastically support the body portion relative to the radial extension in the direction of the rotation axis.

15. The electric drive device according to claim 9, wherein, The first piston and the second piston each include an annular body portion and a plurality of protrusions extending from the radially outer end of the body portion parallel to the axis of rotation.

16. The electric drive device of claim 15, further comprising a piston housing, the piston housing forming a space disposed therein on the radially inner side of the first piston and the second piston. The piston housing includes: A first axial extension extending along the rotation axis; A radial extension portion formed by extending radially outward from the first axial extension portion; as well as A second axial extension extending along the rotation axis at a radial position further away from the rotation axis than the radial position of the first axial extension, and It also includes a return spring for elastically supporting the first piston and the second piston to move relative to the radial extension away from the first force transmission member and the second force transmission member, respectively.

17. The electric drive device according to claim 16, wherein, The first force transmission member and the second force transmission member each have a disc-shaped main body portion and a plurality of protrusions extending from the radially inner end of the main body portion parallel to the axis of rotation, wherein the protrusions of the first piston and the second piston, as well as the protrusions of the first force transmission member and the second force transmission member, are configured to at least partially face the outer peripheral surface of the second axial extension portion.

18. The electric drive device according to claim 16, wherein, The clutch housing includes a sleeve portion extending parallel to the axis of rotation, wherein the sleeve portion and the second axial extension portion are configured to overlap at least partially in the direction of the axis of rotation, and also includes a clutch bearing disposed between the sleeve portion and the second axial extension portion to rotatably support the clutch housing.

Images