Dual-motor coupling two-gear variable-speed distributed driving system

Abstract

The invention discloses a dual-motor coupling two-gear variable speed distributed driving system. The transmission is mainly composed of a first motor, a second motor, a one-way clutch, a first planet row, a second planet row, a main speed reducer, a transmission shell, a hub assembly and the like. And the second planet row adopts a duplex planetary gear train. An output shaft of the first motor is fixedly connected with the first sun gear and the second small sun gear; a second motor rotor is fixedly connected with the first gear ring and the second planet carrier; the one-way clutch is used for connecting the first planet carrier and the transmission shell; the main speed reducer is used for connecting the second large sun gear and the hub assembly. According to the dual-motor coupling two-gear variable-speed distributed driving system, the working state of two gears of dual-motor torque coupling and dual-motor rotating speed coupling can be achieved by controlling the torque rotating speed direction of the first motor and the torque rotating speed direction of the second motor.

Description

Technical Field

[0001] The present invention belongs to the field of electric vehicle drive, and particularly relates to a highly integrated two-speed variable transmission distributed drive system with dual-motor coupling. Background Art

[0002] In recent years, electric vehicles with advantages such as low emissions, high efficiency, and high performance have been vigorously developed. As an important assembly of electric vehicles, the electric drive system is currently also developing towards high integration and distribution. Compared with the centralized drive system, the distributed drive system can shorten the transmission link, improve the transmission efficiency, and reduce the occupancy of the chassis space by integrating the electric drive system into the wheel; in addition, it can also achieve torque vector control through independent control of the driving and braking torques of each wheel, thereby greatly improving the handling stability and driving pleasure of electric vehicles. Currently, it is considered the best driving form for future electric vehicles.

[0003] However, the current distributed drive system mainly adopts a simple single-stage reduction drive or direct drive scheme. This drive scheme has a simple structure, low cost, and relatively mature technology. However, the single-stage reduction drive or direct drive scheme cannot fully utilize the high-efficiency range of the motor itself, and has high requirements for the ultimate performance of the motor. With the gradual popularization of the distributed drive system in the future and the development of the exploration of the motor performance potential entering a bottleneck, the above simple distributed drive system transmission scheme will not be able to meet the increasing diversified operating conditions requirements of electric vehicles. Therefore, it is necessary to explore a new electric drive scheme for distributed drive electric vehicles.

[0004] The present invention proposes a new two-speed variable transmission distributed drive system with dual-motor coupling. It mainly consists of two drive motors, a one-way clutch, a corresponding planetary row coupling mechanism, a main reducer, etc. The system cleverly utilizes the characteristic of the one-way clutch to "automatically disengage" in the reverse direction. By controlling the torque and rotational speed direction of the motor, the first-gear dual-motor torque coupling mode and the second-gear dual-motor speed coupling mode can be achieved without the need for other active actuators. The above two modes can generally improve the overall efficiency of the drive system on the premise of ensuring the power performance of the electric vehicle, thereby increasing the driving range of the electric vehicle and reducing the requirements for the ultimate performance of the motor. Summary of the Invention

[0005] The present invention provides a novel dual-motor coupled two-speed distributed drive system, which cleverly utilizes the reverse automatic disengagement characteristic of the one-way clutch. By controlling the torque output directions of the two motors, a first-gear dual-motor torque coupling mode and a second-gear dual-motor speed coupling mode can be achieved without the aid of other active actuators. The system can give full play to the advantages of dual-motor torque and speed coupling on the premise of ensuring the overall compactness of the mechanism, effectively improving the power performance and economy of the whole vehicle. At the same time, the system can be integrally designed inside the wheel or at the wheel end, conforming to the future development trend of distributed electric drive systems.

[0006] To achieve the above object, the following technical solutions are adopted:

[0007] A dual-motor coupled two-speed distributed drive system consists of a first motor, a second motor, a first planetary gear set, a second planetary gear set, a one-way clutch, a main reducer, a wheel hub assembly, a transmission housing, etc.

[0008] The transmission housing is of an I-shaped structure with openings at both ends, which are respectively used to accommodate and install the first motor, the second motor, the first planetary gear set and the second planetary gear set; the main reducer is arranged at the wheel end and supported in the concave cavity outside the end cover of the second motor, and is used to transmit the force from the suspension system to the wheel hub assembly; the transmission housing is fixed to the vehicle frame through the suspension system.

[0009] The first motor is installed inside the wheel or at the wheel end, and includes a first motor stator, a first motor rotor, a first motor output shaft, and a first motor end cover; the first motor stator is fixed inside the transmission housing; the first motor rotor is fixedly connected to the first motor output shaft through a spline; the first motor output shaft is rotatably supported on the first motor end cover and the first planetary carrier through bearings; the first motor output shaft is fixedly connected to the first sun gear; the first motor housing end cover is screwed to the transmission housing to seal the first motor.

[0010] The second motor is installed inside the wheel or at the wheel end and is arranged coaxially with the first motor; the second motor includes a second motor stator, a second motor rotor, and a second motor end cover. The second motor stator is fixed inside the transmission housing, and the second motor rotor is rotatably supported on the transmission housing and the second motor end cover through bearings; the second motor end cover is screwed to the transmission housing to seal the second motor, and torque is output through the second motor rotor.

[0011] The first planetary gear set includes a first sun gear, a first planet gear, a first ring gear, and a first planet carrier. The first sun gear receives torque from the first motor and meshes with the first planet gear for external meshing transmission. The first planet gear is rotatably supported on the first planet carrier and meshes with the first ring gear for internal meshing transmission. The first ring gear is fixedly connected to the second motor rotor, and the first planet carrier is rotatably supported on the transmission housing.

[0012] The one-way clutch is used to connect the first planet carrier and the transmission housing. It includes an inner race and an outer race. The inner race is fixedly connected to the first planet carrier, and the outer race is fixedly connected to the transmission housing. When the inner race has a reverse rotation tendency relative to the outer race (with the wheel rotation direction being positive when the vehicle is moving forward), the one-way clutch is in a locked state; when the inner race rotates forward relative to the outer race, the one-way clutch is in a disengaged state.

[0013] The second planetary gear set adopts a double planetary gear train and includes a second small sun gear, a second large planet gear, a second small planet gear, a second large sun gear, and a second planet carrier. The second small sun gear is fixedly connected to the first sun gear. The second large planet gear is rotatably supported on the second planet carrier and meshes with the second small sun gear for external meshing transmission. The second small planet gear is rotatably supported on the second planet carrier and meshes with the second large sun gear for external meshing transmission. The second small planet gear and the second large planet gear are integrally formed. The second planet carrier is fixedly connected to the second motor rotor.

[0014] The main reducer receives torque from the second large sun gear, reduces the speed and increases the torque, and then outputs it to the hub assembly. It adopts a planetary gear set mechanism and includes an intermediate shaft, a third sun gear, a third planet gear, a third ring gear, and a third planet carrier. The intermediate shaft is fixedly connected to the second large sun gear and is rotatably supported on the second motor end cover and the hub assembly. The third sun gear is fixedly connected to the intermediate shaft through a spline. The third planet gear meshes with the third sun gear for external meshing transmission and is rotatably supported on the third planet carrier. The third ring gear meshes with the third planet gear for internal meshing transmission and is fixedly connected to the second motor housing.

[0015] The wheel hub assembly includes a support ring, wheel spokes, a wheel hub bearing, a central fixing large nut, wheel hub bolts, and a brake disc; the support ring is rotatably supported on the second motor end cover through the wheel hub bearing and is used to receive the force from the suspension system transmitted through the transmission housing; an external thread is machined on the outer side port of the second motor end cover, and the central fixing large nut is installed on the external thread of the outer side port of the second motor end cover for axially fixing the wheel hub bearing; the wheel spokes are fixedly connected to the support ring through a plurality of the wheel hub bolts; the brake disc is fixedly connected to the support ring; the third planet carrier is fixedly connected to the wheel spokes and transmits the driving and braking torque to the tire through the wheel spokes.

[0016] The dual-motor coupled two-speed distributed drive system according to the present invention can achieve the working states of dual-motor torque coupling and dual-motor speed coupling in two gears by controlling the torque, speed, and direction of the first motor and the second motor. When the first motor rotates forward to output a forward torque and the second motor rotates backward to output a reverse torque, and the following relationship is satisfied: n m1 =-k1n m2 When, the one-way clutch is in a locked state, and the system is in the first-gear dual-motor torque coupling drive state. In the formula, n m1 is the speed of the first motor, n m2 is the speed of the second motor, and k1 is the characteristic parameter of the first planetary gear set. When both the first motor and the second motor rotate forward to output forward torques, the one-way clutch is in a disengaged state, and the system is in the second-gear dual-motor speed coupling drive state.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. For the dual-motor coupled two-speed distributed drive system according to the present invention, by skillfully utilizing the automatic disengagement characteristic of the one-way clutch and controlling the torque, speed, and direction of the two motors, two gear modes of first-gear dual-motor torque coupling and second-gear dual-motor speed coupling can be achieved without relying on other active actuating mechanisms, thereby effectively reducing the system complexity and facilitating the integrated design.

[0019] 2. For the dual-motor coupled two-speed distributed drive system according to the present invention, through the dual-motor torque coupling drive and the dual-motor speed coupling drive, the dynamic performance and economy of the whole vehicle can be greatly improved, and the utilization rate of the high-efficiency interval of the motor can be increased.

[0020] 3. For the dual-motor coupled two-speed distributed drive system according to the present invention, by reasonably controlling the torque and speed of the two motors, seamless switching between the two gear modes can be achieved, ensuring the acceleration performance and longitudinal ride comfort of the vehicle.

[0021] 4. A dual-motor coupled two-speed variable transmission distributed drive system according to the present invention realizes distributed drive by integrating the system inside the wheel or at the wheel hub, which can greatly improve the vehicle's handling stability and driving pleasure and conforms to the future development trend of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a dual-motor coupled two-speed variable transmission distributed drive system according to the present invention.

[0023] Figure 2 It is a structural diagram of a dual-motor coupled two-speed variable transmission distributed drive system according to the present invention.

[0024] Figure 3 It is a schematic diagram of the torque flow in the torque coupling state of the dual motors of a dual-motor coupled two-speed variable transmission distributed drive system according to the present invention.

[0025] Figure 4 It is a schematic diagram of the torque flow in the speed coupling state of the dual motors of a dual-motor coupled two-speed variable transmission distributed drive system according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following further describes the present invention in detail with reference to the accompanying drawings so that those skilled in the art can implement it according to the description in the specification. An embodiment of a hub motor two-speed variable transmission system with an integrated and reused electro-mechanical brake according to the present invention is described as follows:

[0027] As shown in Figure 1 、 Figure 2 , a dual-motor coupled two-speed variable transmission distributed drive system is composed of a first motor 100, a second motor 200, a first planetary gear set 300, a second planetary gear set 400, a one-way clutch 500, a main reducer 600, a wheel hub assembly, a transmission housing, etc.

[0028] The transmission housing includes a main housing 801, a first motor end cover 802, and a second motor end cover 803, which are used to install the first motor 100, the second motor 200, the main reducer 600, the first planetary gear set 300 and the second planetary gear set 400, the one-way clutch 500, etc.; the main housing 801 is fixed to the vehicle frame through a suspension system and is used to transmit the force from the suspension system to the wheel hub assembly; the first motor end cover 802 is fixedly connected to the main housing 801 through a plurality of bolts 804; the second motor end cover 803 is fixedly connected to the main housing 801 through a plurality of bolts 805.

[0029] The first motor 100 is installed inside the wheel or at the wheel end, and includes a first motor stator 101, a first motor rotor 102, and a first motor output shaft 103. The first motor stator 101 is fixed inside the cavity of the main housing 801. The first motor rotor 102 is fixedly connected to the first motor output shaft 103 through a spline. The first motor output shaft 103 is rotatably supported on the first motor end cover 802 and the first planet carrier 304 through bearings. The first motor output shaft 103 is integrally formed with the first sun gear 301.

[0030] The second motor 200 is installed inside the wheel or at the wheel end and is coaxially arranged with the first motor 100. The second motor 200 includes a second motor stator 201 and a second motor rotor 202. The second motor stator 201 is fixed inside the cavity outside the main housing 801. The second motor rotor 202 is rotatably supported on the main housing 801 and the second motor end cover 803 through bearings, and torque is output through the second motor rotor 202.

[0031] The first planetary gear set 300 includes a first sun gear 301, a first planet gear 302, a first ring gear 303, and a first planet carrier 304. The first sun gear 301 receives the torque from the first motor output shaft 103 and meshes with the first planet gear 302 externally. The first planet gear 302 is rotatably supported on the first planet carrier 304 and meshes with the first ring gear 303 internally. The first ring gear 303 is fixedly connected to the second motor rotor 202. The first planet carrier 304 is rotatably supported on the main housing 801 through bearings.

[0032] The one-way clutch 500 is used to connect the first planet carrier 304 and the main housing 801, and includes an inner ring 502 and an outer ring 501. The inner ring 502 is fixedly connected to the first planet carrier 304 through a spline. The outer ring 501 is fixedly connected to the main housing 801 through a spline. When the inner ring 502 has a reverse rotation tendency relative to the outer ring 501 (with the wheel rotation direction being positive when the vehicle is moving forward), the one-way clutch 500 is in a locked state. When the inner ring 502 rotates forward relative to the outer ring 501, the one-way clutch 500 is in a disengaged state.

[0033] The second planetary gear set 400 adopts a double-row planetary gear train, including a second small sun gear 401, a second large planet gear 402, a second small planet gear 403, a second large sun gear 404, and a second planet carrier 405. The second small sun gear 401 is fixedly connected to the first sun gear 301. The second large planet gear 402 is rotatably supported on the second planet carrier 405 and is in external meshing transmission with the second small sun gear 401. The second small planet gear 403 is rotatably supported on the second planet carrier 405 and is in external meshing transmission with the second large sun gear 404. The second small planet gear 402 and the second large planet gear 403 are integrally formed. The second planet carrier 405 is fixedly connected to the second motor rotor 202;

[0034] The main reducer 600 is used to receive the torque from the second large sun gear 404, reduce the speed and increase the torque, and then output it to the hub assembly. It adopts a planetary gear set mechanism, including an intermediate shaft 605, a third sun gear 601, a third planet gear 602, a third ring gear 603, and a third planet carrier 604. The intermediate shaft 605 is integrally formed with the second large sun gear 404 and is rotatably supported on the second motor end cover 803 and the hub assembly through bearings. The third sun gear 601 is fixedly connected to the intermediate shaft 605 through a spline. The third planet gear 602 is in external meshing transmission with the third sun gear 601 and is rotatably supported on the third planet carrier 604. The third ring gear 603 is in internal meshing transmission with the third planet gear 602 and is fixedly connected to the second motor end cover 803.

[0035] The hub assembly includes a support ring 704, a wheel spoke 706, hub bearings 701 and 702, a central fixing large nut 703, hub bolts 705, and a brake disc 707. The support ring 704 is rotatably supported on the second motor end cover 803 through the hub bearings 701 and 702, and is used to receive the force from the suspension system transmitted through the main housing 801. The outer port of the second motor end cover 803 is machined with an external thread, and the central fixing large nut 703 is installed on the external thread of the outer port of the second motor end cover 803 to axially fix the hub bearing 702. The wheel spoke 706 is fixedly connected to the support ring 704 through a plurality of the hub bolts 705. The brake disc 707 is fixedly connected to the support ring 704. The third planet carrier 604 is fixedly connected to the wheel spoke 706 through a plurality of bolts 606, and transmits the driving and braking torques from the first motor 100 and the second motor 200 to the tire through the wheel spoke 706.

[0036] The two-speed variable transmission distributed drive system with dual-motor coupling according to the present invention can achieve the working states of dual-motor torque coupling and dual-motor speed coupling in two gears by controlling the torque, speed and direction of the first motor 100 and the second motor 200. When the first motor 100 rotates forward to output a forward torque and the second motor 200 rotates backward to output a reverse torque, the one-way clutch 500 is in a locked state, and the system is in the first-gear state of dual-motor torque coupling drive. The schematic diagram of the relevant torque flow is as shown in Figure 3 shown. When both the first motor 100 and the second motor 200 rotate forward to output forward torques, the one-way clutch 500 is in a disengaged state, and the system is in the second-gear drive state of dual-motor speed coupling. The schematic diagram of the relevant torque flow is as shown in Figure 4 shown.

[0037] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples here.

Claims

1. A dual-motor coupled two-speed variable speed distributed drive system, characterized in that: include: A first motor is installed inside the wheel or on the wheel side; A second motor is installed in the wheel or on the wheel side, is coaxially arranged with the first motor, and outputs torque through the second motor rotor; A first planetary gear, comprising a first sun gear, a first planetary gear, a first ring gear and a first planet carrier, wherein the first sun gear receives torque from the first motor and is externally meshed with the first planetary gear for transmission, the first planetary gear is rotatably supported on the first planet carrier and is internally meshed with the first ring gear for transmission, the first ring gear is fixedly connected to the rotor of the second motor, and the first planet carrier is rotatably supported on a transmission housing; a one-way clutch, used for connecting the first planet carrier and the transmission housing; The second planetary row adopts a double-linked planetary gear system, including a second small sun gear, a second large planetary gear, a second small planetary gear, a second large sun gear, and a second planet carrier, wherein the second small sun gear is fixedly connected to the first sun gear, the second large planetary gear is rotatably supported by the second planet carrier and meshes with the second small sun gear for transmission, the second small planetary gear is rotatably supported by the second planet carrier and meshes with the second large sun gear for transmission, the second small planetary gear is integrally formed with the second large planetary gear, and the second planet carrier is fixedly connected to the second motor rotor; The main reducer receives the torque from the second largest sun gear, reduces the speed and increases the torque before outputting it to the hub assembly; The dual-motor coupled two-speed variable speed distributed drive system described in the present invention can achieve two-speed working states of dual-motor torque coupling and dual-motor speed coupling by controlling the torque and speed of the first motor and the second motor.

2. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that The transmission housing is an I-shaped structure with openings at both ends, and is respectively used to accommodate and install the first motor and the second motor and the first planetary gear and the second planetary gear; the main reducer is arranged at the wheel end and supported in the recessed cavity outside the second motor end cover, and is used to transmit the force from the suspension system to the wheel hub assembly; the transmission housing is fixed to the vehicle frame through the suspension system.

3. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that: The first motor comprises a first motor stator, a first motor rotor, a first motor output shaft, and a first motor end cover; the first motor stator is fixed in the transmission housing; the first motor rotor is fixedly connected to the first motor output shaft via a spline; the first motor output shaft is rotatably supported on the first motor end cover and the first planetary carrier via a bearing; the first motor output shaft is fixedly connected to the first sun gear; the first motor end cover is screwed to the transmission housing to seal the first motor.

4. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that: The second motor comprises a second motor stator, a second motor rotor and a second motor end cover, wherein the second motor stator is fixed in the transmission housing, and the second motor rotor is rotatably supported by the transmission housing and the second motor end cover respectively through bearings; The second motor end cover is screwed to the transmission housing to seal the second motor.

5. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that: The second motor rotor and the first motor rotor are hollow inside, and the first planetary gear, the second planetary gear, and the one-way clutch are installed in the hollow space inside the first motor rotor and the second motor rotor to save the space size of the wheel hub.

6. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 4, characterized in that The main reducer adopts a planetary gear mechanism, including an intermediate shaft, a third sun gear, a third planetary gear, a third ring gear, and a third planet carrier. The intermediate shaft is fixedly connected to the second large sun gear and is rotatably supported on the second motor end cover and the hub assembly. The third sun gear is fixedly connected to the intermediate shaft via a spline. The third planetary gear is externally meshed with the third sun gear and is rotatably supported on the third planet carrier. The third ring gear is internally meshed with the third planetary gear and is fixedly connected to the second motor end cover.

7. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 4, characterized in that The wheel hub assembly includes a support ring, a wheel spoke, a wheel hub bearing, a central fixed large nut, a wheel hub bolt, and a brake disc; the support ring is rotatably supported on the second motor end cover through the wheel hub bearing, and is used to receive the force from the suspension system transmitted through the transmission housing; the outer port of the second motor end cover is processed with an external thread, and the central fixed large nut is installed on the external thread of the outer port of the second motor end cover, and is used to axially fix the wheel hub bearing; the wheel spoke is fixedly connected to the support ring through a plurality of the wheel hub bolts; the brake disc is fixedly connected to the support ring; the third planetary carrier is fixedly connected to the wheel spoke, and transmits the driving braking torque to the tire through the wheel spoke.

8. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that: The one-way clutch is used to connect the first planetary carrier and the transmission housing, and includes an inner ring and an outer ring, wherein the inner ring is fixedly connected to the first planetary carrier, and the outer ring is fixedly connected to the transmission housing. When the inner ring has a reverse rotation tendency relative to the outer ring (taking the wheel rotation direction when the vehicle is moving forward as positive), the one-way clutch is in a locked state; when the inner ring rotates forward relative to the outer ring, the one-way clutch is in a disengaged state.

9. A dual-motor coupled two-speed variable speed distributed drive system as claimed in claim 1, characterized in that: When the first motor rotates forward to output a positive torque, and the second motor rotates reversely to output a reverse torque, and the following relationship is satisfied: m1 =-k1n m2 When the one-way clutch is in the locked state, the system is in the first gear state of dual motor torque coupling drive, where n m1 is the speed of the first motor, n m2 is the speed of the second motor, k1 is the characteristic parameter of the first planetary gear; when the first motor and the second motor both rotate forward and output positive torque, the one-way clutch is in a disengaged state, and the system is in a dual-motor speed-coupled second-gear drive state.

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