Rear axle electric drive device

Abstract

A rear axle electric drive device. The present application relates to vehicle transmission technology and driving field, the first motor is through planetary gear mechanism and is transmitted to the wheel, the planetary gear mechanism includes input component, first output component, first planetary gear, second output component, second planetary gear, first intermediate component and second intermediate component, the input component is connected to the motor, the first output component and the second output component are connected to one of the wheel respectively, two first intermediate components are symmetrically arranged on the left and right sides of the rotating staggered shaft gear and are engaged with the rotating staggered shaft gear transmission, the rotating staggered shaft gear is arranged on the rotating shaft sleeve and is rotatably centered connection;It also includes brake element, for keeping the rotating shaft sleeve fixed, when the brake element brakes the rotating shaft sleeve, the first output component and the first output component of the electric drive device realize differential output;When the brake element is unlocked and releases the rotating shaft sleeve, the input component of the electric drive device realizes decoupling idling, and the electric drive device with power disengagement performance is obtained.

Description

Technical Field

[0001] This invention relates to vehicle transmission technology and drive technology, specifically to a rear axle electric drive device. Background Technology

[0002] Some existing passenger vehicles use multi-axle drive, with a single or dual-motor electric drive unit installed on the rear axle to provide sufficient power performance. However, in actual use, front-wheel drive can meet most driving conditions in urban areas, which means that the rear axle electric drive unit is mainly dragged, resulting in significant drag losses at higher vehicle speeds, including large electromagnetic losses of the permanent magnet motor that are closely related to speed, as well as oil churning losses in the transmission mechanism.

[0003] Currently, various disengagement devices, similar to gear shifting mechanisms, have emerged to disconnect and connect shafts, but sometimes they fail to engage the gears in a timely manner. There is also a need for an electric drive device that can overcome the shortcomings of existing disengagement devices and reduce drag losses.

[0004] Therefore, we propose a rear axle electric drive device to solve the above problems. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a rear axle electric drive device that overcomes the drawbacks of existing disengagement devices mentioned in the background section and reduces drag losses.

[0006] (II) Technical Solution To achieve the above objectives, the present invention specifically adopts the following technical solution: A rear axle electric drive device includes: a first motor; the first motor transmits power to the wheels via a planetary gear mechanism, the planetary gear mechanism including an input component, a first output component, a first planetary gear, a second output component, a second planetary gear, a first intermediate component, and a second intermediate component; the input component is connected to the first motor, the first output component and the second output component are respectively connected to one of the wheels, the two first intermediate components are symmetrically arranged on the left and right sides of a rotating interlaced shaft gear and both mesh with the rotating interlaced shaft gear for transmission, the rotating interlaced shaft gear is mounted on a rotating bushing for rotational centering connection, and the two second intermediate components are fixedly connected; it also includes a braking element for holding the rotating bushing in place.

[0007] Furthermore, during driving, the braking element locks and fixes the rotating bushing, the input component transmits power to the wheels, and the first output component and the second output component can output power differentially during steering.

[0008] Furthermore, during driving, the braking element unlocks and releases the rotating bushing, disconnecting the transmission path between the input component and the first output component and the second output component.

[0009] Furthermore, the braking element is any one of a mechanical engagement device, a one-way clutch, an electromagnetic brake, and a hydraulic clutch.

[0010] Furthermore, when the first planetary gear and the second planetary gear have completely identical characteristic parameters, the motor and the second motor can be respectively connected to the input component. In this state, the planetary gear transmission mechanism also achieves power disengagement or differential output by controlling the rotation and fixed state of the rotating bushing through the braking element.

[0011] Furthermore, the reduction ratio achieved by the planetary gear transmission mechanism can be calculated according to formula (1): ; In the formula, Zs1, Zp1, Zr and Zp2 are the number of teeth of the first sun gear, the first planet gear, the gear ring and the second planet gear, respectively; the gear matching scheme is: Zs1=27, Zp1=48, Zr=87 and Zp2=16, i=10.67 can be obtained from formula (1).

[0012] The reduction ratio achieved by the planetary gear transmission mechanism can be calculated according to formula (1). The planetary gear transmission mechanism can achieve the corresponding reduction ratio when going straight, turning and slipping and locking. When turning at the center of rotation, the rotating intersecting gear can rotate, the second sun gear rotates at 0, and the reduction ratio of the planetary gear transmission mechanism is calculated according to formula (2): ; In the formula, Zs2 is the number of teeth of the second sun gear. The gear matching yields Zs2=51. According to formula (2), i=-4.67 can be obtained. This means that the two first motors and the second motor not only have opposite rotational directions, but also have opposite rotational directions to the wheels on the same side, so as to achieve the same right or left center turn.

[0013] Furthermore, for fixed-point steering, the speed relationship between the outer motor and the inner motor can be obtained as follows (3): ; In the formula, n2 is the speed of the outer motor and n1 is the speed of the inner motor. According to the gear matching, n2 = 0.3913n1 can be obtained, that is, the speed directions of the inner and outer motors are the same. The torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor can drive the outer wheel.

[0014] Furthermore, the planetary gear includes a first planetary gear and a second planetary gear fixedly connected to each other. The first planetary gear meshes with the sun gear and the first ring gear simultaneously, and the second planetary gear meshes with the second ring gear. The first ring gear is also provided with bevel teeth that mesh with the bevel gear for transmission. The sun gear serves as the input component, the second ring gear serves as the output component, the first ring gear serves as the first intermediate component, and the planet carrier serves as the second intermediate component.

[0015] Furthermore, the reduction ratio achieved by the planetary gear transmission mechanism can be calculated according to formula (4): ; In the formula, Zs, Zr1, Zp1, Zp2 and Zr2 are the number of teeth of the sun gear, the first gear ring, the first planet gear, the second planet gear and the second gear ring, respectively; the gear matching scheme is: Zs=16, Zp1=32, Zr1=80, Zp2=16 and Zr2=64; i=16 can be obtained from formula (4); For straight-line, turning, and slip lock-up, the planetary gear transmission mechanism can achieve the corresponding reduction ratio; When turning at the center of rotation, the rotating interleaved shaft gear can rotate, the planetary carrier speed is 0, and the reduction ratio of the planetary gear transmission mechanism is calculated according to formula (5): ; According to equation (5), i = -8 can be obtained.

[0016] Furthermore, for fixed-point steering, the speed relationship between the outer motor and the inner motor is obtained as follows (6): ; In the formula, n2 is the speed of the outer motor and n1 is the speed of the inner motor. According to the gear matching, n2 = 0.3333 n1, that is, the speed directions of the inner and outer motors are the same. The torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor drives the outer wheel.

[0017] (III) Beneficial Effects Compared with the prior art, the present invention provides a rear axle electric drive device, which has the following advantages: In this invention, a motor transmits power to the tire via a planetary gear set mechanism. Two first intermediate components are symmetrically arranged on the left and right sides of a rotatable interlocking gear set and mesh with it. The rotatable interlocking gear set is radially centered on a rotating sleeve. Two second intermediate components are fixedly connected. A braking element is also provided to selectively hold the rotating sleeve in place. When the braking element engages and holds the rotating sleeve in place, the motor power can be transmitted to the tire via the planetary gear set mechanism, providing a differential function during steering. When the braking element unlocks and the rotating sleeve rotates freely, the internal transmission path of the planetary gear set mechanism is interrupted, and the motor and tire are disengaged. This results in an electric drive device that overcomes the shortcomings of existing disengagement devices and reduces drag losses. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 The diagram shown is a transmission schematic of the rear axle electric drive device in the first specific embodiment. Figure 2 The diagram shown is a transmission schematic of the rear axle electric drive device in the second specific embodiment.

[0019] Figure 3 The diagram shown is a transmission schematic of the rear axle electric drive device in the second specific embodiment.

[0020] Symbol explanation: 11, First motor; 12, Second motor; 13, Rotating bushing; 20, Planetary gear mechanism; 21, Input component; 22, First output component; 22a, Second output component; 23, First planetary gear; 23a, Second planetary gear; 24, First intermediate component; 25, Second intermediate component; 231, First planetary gear; 232, Second planetary gear; 26, Rotating interlocking shaft gear; 27, Braking element; 30, Wheel. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example Example 1:

[0023] Figure 1The diagram shown is a transmission schematic of the electric drive device according to a first specific embodiment. Figure 1 As shown, a rear axle electric drive device includes: a first motor 11; the first motor 11 and a planetary gear set 20 to transmit power to a wheel 30. The planetary gear set 20 includes an input component 21, a first output component 22, a second output component 22a, a first planetary gear 23, a second planetary gear 23a, a first intermediate component 24, and a second intermediate component 25. The input component 21 is connected to the first motor 11, and the first output component 22 and the second output component 22a are connected to one of the wheels 30. The two first intermediate components 24 are symmetrically arranged on the left and right sides of a rotatable rotating interlaced shaft gear 26 and are both engaged with the rotatable rotating interlaced shaft gear 26 for transmission. The rotatable rotating interlaced shaft gear 26 is radially centered and connected to a rotating bushing 13. The two second intermediate components 25 are fixedly connected. The device also includes a braking element 27 for locking the rotating bushing 13 in place.

[0024] It should be noted that, in this article, locking or latching refers to operating one component to apply a force to another component, causing the component to be fixed or stationary and not to rotate, while unlocking refers to operating one component to make the force acting on the other component disappear, thereby allowing the component to rotate.

[0025] Furthermore, for clarity, the specific operating conditions described below will use left and right sides as shown in the figure to indicate components such as planetary gear sets or wheels, and the description will mostly use the left or leftward state as the reference. This does not affect the specific content, and the right or rightward state can also be inferred by analogy without any doubt.

[0026] Specifically, the braking element 27 locks and fixes the rotating bushing 13. Since the two second intermediate components 25 are fixedly connected, the output torque of the first motor 11, when passing through the planetary gear mechanism 20, acts on the left and right sides of the rotatable interlocking shaft gear 26 via the first intermediate component 24, and the resulting torques cancel each other out. Therefore, the output torque of the first output component 22 and the first output component 22a is always the same. When the interlocking shaft gear 26 is not rotating, the speeds of the first output component 22 and the first output component 22a are the same. When the interlocking shaft gear 26 rotates, the first output component 22 and the first output component 22a output at a differential speed. Figure 2 As shown, if the actual torque difference generated by the first motor 11 and the second motor 12 is 5 Nm, and assuming that the transmission ratio between the bevel gear 26 and the bevel teeth on the first intermediate component 24 that meshes with it is 1 / (2k) of the structural characteristic parameter k of the planetary gear 20, then the driving torque generated on the bevel gear 26 is 10 Nm, and the braking element 27 and / or the rotating bushing 13 should generate a braking torque slightly greater than 10 Nm, thereby keeping the rotating interlaced shaft gear 26 fixed and not rotating.

[0027] When turning, the braking element 27 and / or the rotating bushing 13 are unlocked, and the rotating interlocking gear 26 rotates. When turning, the rotational speeds of the two wheels 30 are different, the rotational speeds of the two output components 22 are different, the rotating interlocking gear 26 performs a differential function, the rotational speeds of the two first intermediate components 24 are the same but in opposite directions, and the rotational speeds of the two second intermediate components 25 are the same.

[0028] The rotating bushing 13 not only generates braking or locking torque applied to the rotating interlaced gear 26, but it also functions as a torque vectoring motor, outputting torque to adjust the driving torque on both wheels 30, thereby achieving better lateral dynamic characteristics. In a dual-motor independent wheel drive system, torque vectoring is achieved by adjusting the output torque of the two motors. However, when the desired torque of the outer motor exceeds its external characteristics, the required function cannot be achieved. By utilizing the rotating bushing 13 to provide greater torque, the torque vectoring function can be further expanded.

[0029] Specifically, when entering a left turn while driving straight, the braking element 27 and / or the rotating bushing 13 unlock, the torque of the first motor 11 decreases and the torque of the second motor 12 increases. When the desired torque of the second motor 12 is greater than the external characteristic of the motor, the output torque of the rotating bushing 13 acts on the rotating interlocking shaft gear 26, causing the torque of the right first intermediate member 24 to increase and the torque of the left first intermediate member 24 to decrease, thereby increasing the torque on the right output member 22 to the desired value and decreasing the torque on the left output member 22 to the desired value.

[0030] When steering, torque vector control is applied to the first motor 11 and the second motor 12. The output torque of the outer motor increases while the output torque of the inner motor decreases. Typically, the torque increments on both sides are equal in value but opposite in direction. If the desired torque value is greater than the motor's external characteristics, then if a rotating bushing 13 is configured, the difference in driving torque on both wheels 30 can be further amplified using the rotating bushing 13, thus enhancing the torque vector function.

[0031] Specifically, when turning left from a stationary position, the braking element 27 and / or the rotating bushing 13 unlock, and the first motor 11 and the second motor 12 output torques of equal magnitude but opposite direction. After being reduced in speed by the planetary gear set 20, these torques drive the wheels 30 on both sides, causing the vehicle to turn left around its center. Road resistance varies on different surfaces, and different turning speeds require different driving torques. The output torques of the first motor 11 and the second motor 12 can be set according to specific conditions to meet power requirements.

[0032] Specifically, during a fixed-point left turn, the left wheel 30 is braked and locked by the vehicle's braking system, while the braking element 27 and / or rotating bushing 13 are unlocked. The second motor 12 transmits power via the planetary gear set 20 to the right output component 22, driving the right wheel 30 and causing the vehicle to turn left around one of its wheels. Fixed-point steering means that a four-wheeled vehicle can rotate around a specific wheel that is locked by a wheel brake. The outer first motor 11 or the second motor 12 drives the outer wheel 30 forward or backward, thereby achieving a fixed-point turn to the left or right.

[0033] Specifically, when the left wheel 30 slips, the braking element 27 and / or the rotating bushing 13 locks, and the power of the first motor 11 is transmitted from the second intermediate member 25 to the right second intermediate member 25 via the left planetary gear 20, and then to the right output member 22. The power of the first motor 11 is then combined with the power transmitted from the second motor 12 to the right output member 22 via the right planetary gear 20 to drive the right wheel 30.

[0034] The second intermediate component 25 set in the planetary gear set 20, and the two second intermediate components 25 are fixedly connected, not only ensures straight-line performance, but also constructs a transmission branch between the two planetary gear sets 20, thereby transmitting the power of the first motor 11 or the second motor 12 on one side to the planetary gear set 20 on the other side. This achieves the function of transmitting all power to the non-slipping wheel 30 when a differential lock is present. Figure 1 As shown, a specific embodiment of the planetary gear set 20 is as follows: the planetary gear 23 includes a first planetary gear 231 and a second planetary gear 232 that are fixedly connected to each other. The first planetary gear 231 meshes with the first sun gear, and the second planetary gear 232 meshes with the gear ring. The gear ring is also provided with bevel teeth that mesh with the bevel gear 26 for transmission. The second sun gear and the second planetary gear 232 are configured such that the first sun gear serves as the input component 21, the planet carrier serves as the output component 22, the gear ring serves as the first intermediate component 24, and the second sun gear serves as the second intermediate component 25.

[0035] The reduction ratio achievable by planetary gear 20 can be calculated according to formula (1): ; In the formula, Zs1, Zp1, Zr and Zp2 are the number of teeth of the first sun gear, the first planet gear 231, the gear ring and the second planet gear 232, respectively. One gear matching scheme is: Zs1=27, Zp1=48, Zr=87 and Zp2=16. According to formula (1), i=10.67 can be obtained.

[0036] The achievable reduction ratio of planetary gear 20 can be calculated according to formula (1), which will not be elaborated here. For Figure 2 In this scheme, the planetary gear set 20 can achieve the corresponding reduction ratio when going straight, turning, and when slipping and locking.

[0037] When turning around in place, bevel gear 26 can rotate, the second sun gear rotates at 0, and the reduction ratio of planetary gear set 20 is calculated according to formula (2): ; In the formula, Zs2 is the number of teeth of the second sun gear, and Zs2 = 51 is obtained by matching the teeth. According to formula (2), i = -4.67 can be obtained. This means that the two first motors 11 and the second motor 12 not only have opposite rotational directions, but also have opposite rotational directions to the wheels on the same side, so that the same center-of-spot turning to the right or left can be achieved.

[0038] In addition, other gear matching schemes can be adopted to further improve the value of the speed ratio obtained by formula (2) on the premise that the speed ratio obtained by formula (1) reaches the desired value.

[0039] For fixed-point steering, the speed relationship between the outer motor and the inner motor can be obtained as follows (3): ; In the formula, n2 is the rotational speed of the outer motor, and n1 is the rotational speed of the inner motor. According to the gear matching, n2 = 0.3913n1, that is, the rotational speeds of the inner and outer motors are in the same direction. Torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor can drive the outer wheel.

[0040] Example 2: Figure 3 The diagram shown is a transmission schematic of the rear axle electric drive device in the second specific embodiment. Figure 3 As shown, another specific embodiment of the planetary gear set 20 is as follows: the planetary gear 23 includes a first planetary gear 231 and a second planetary gear 232 that are fixedly connected to each other. The first planetary gear 231 meshes with the sun gear and the first ring gear simultaneously, and the second planetary gear 232 meshes with the second ring gear. The first ring gear is also provided with bevel teeth that mesh with the bevel gear 26 for transmission. The sun gear serves as the input component 21, the second ring gear serves as the output component 22, the first ring gear serves as the first intermediate component 24, and the planet carrier serves as the second intermediate component 25.

[0041] The reduction ratio achievable by planetary gear 20 can be calculated according to formula (4): ; In the formula, Zs, Zr1, Zp1, Zp2, and Zr2 are the number of teeth of the sun gear, the first ring gear, the first planet gear, the second planet gear, and the second ring gear, respectively. One gear configuration is: Zs=16, Zp1=32, Zr1=80, Zp2=16, and Zr2=64. According to formula (4), i=16 can be obtained.

[0042] for Figure 3In this scheme, the planetary gear set 20 can achieve the corresponding reduction ratio when going straight, turning, and when slipping and locking.

[0043] When turning at the center of rotation, bevel gear 26 can rotate, the planetary carrier speed is 0, and the reduction ratio of planetary gear set 20 is calculated according to formula (5): ; According to equation (5), i = -8 can be obtained. Other gear matching schemes can also be adopted to further improve the value of the speed ratio obtained by equation (5) on the premise of ensuring that the speed ratio obtained by equation (4) reaches the desired value.

[0044] For fixed-point steering, the speed relationship between the outer motor and the inner motor can be obtained as follows (6): ; In the formula, n2 is the rotational speed of the outer motor, and n1 is the rotational speed of the inner motor. According to the gear matching, n2 = 0.3333n1, that is, the rotational speeds of the inner and outer motors are in the same direction. Torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor can drive the outer wheel.

[0045] Braking element 27 can be a single-disc or multi-disc brake, which can be selected according to specific circumstances, whether it is electromechanical, electromagnetic, pneumatic or electrohydraulic. Using a disc brake allows the differential lock to function without stopping when encountering slippery road surfaces during driving, whereas a conventional differential lock requires stopping and locking before continuing to drive.

[0046] The electric drive unit can be used as either the rear axle or the front axle, depending on the specific circumstances.

[0047] In summary, in this invention, the motor transmits power to the tire via a planetary gear set 20. Two first intermediate components 24 are symmetrically arranged on the left and right sides of a rotatable interlocking gear set 26 and mesh with it. The rotatable interlocking gear set 26 is radially centered on a rotating sleeve 13. Two second intermediate components 25 are fixedly connected. A braking element 27 is also provided to selectively hold the rotating sleeve 13 in place. When the braking element 27 brakes and holds the rotating sleeve 13 in place, the motor power can be transmitted to the tire via the planetary gear set 20, providing a differential function during steering. When the braking element 27 unlocks the rotating sleeve 13 and it rotates freely, the internal transmission path of the planetary gear set 20 is interrupted, and the motor and tire are disengaged. This results in an electric drive device that overcomes the shortcomings of existing disengagement devices and reduces drag losses.

[0048] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rear axle electric drive device, characterized in that, include: The first motor (11) transmits power to the wheels (30) through the planetary gear transmission mechanism (20); The planetary gear transmission mechanism (20) includes an input component (21), a first output component (22), a first planetary gear (23), a second output component (22a), a second planetary gear (23a), a first intermediate component (24), and a second intermediate component (25). The input component (21) is connected to the first motor (11), the first output component (22) and the second output component (22a) are connected to one of the wheels (30), the two first intermediate components (24) are symmetrically arranged on the left and right sides of the rotating interlaced shaft gear (26) and both mesh with the rotating interlaced shaft gear (26) for transmission, the rotating interlaced shaft gear (26) is mounted on the rotating bushing (13) for rotational centering connection, and the two second intermediate components (25) are fixedly connected; It also includes the braking element (27) for braking and fixing the rotating bushing (13).

2. The rear axle electric drive device according to claim 1, characterized in that, The braking element (27) brakes the rotating bushing (13) to fix it. The power of the first motor (11) is transmitted to the wheel (30) through the planetary gear mechanism (20). At the same time, the first output component (22) and the second output component (22a) output at different speeds.

3. The rear axle electric drive device according to claim 1, characterized in that, The braking element (27) unlocks the rotation of the rotating bushing (13), and the transmission path between the first motor (11) and the wheel (30) inside the planetary gear mechanism (20) is broken.

4. The rear axle electric drive device according to claim 1, characterized in that, The braking element (27) is any one of a mechanical engagement device, a one-way clutch, an electromagnetic brake, and a hydraulic clutch.

5. A rear axle electric drive device according to claim 1, characterized in that, When the first planetary gear (23) and the second planetary gear (23a) have the same characteristic parameters, the motor (11) and the second motor (12) are respectively connected to the left and right input components (21). The planetary gear transmission mechanism (20) can brake or unlock the rotating bushing (13) through the braking element (27) to achieve power differential output or power disengagement.

6. A rear axle electric drive device according to claim 1, characterized in that, The reduction ratio achieved by the planetary gear transmission mechanism (20) can be calculated according to formula (1): ； In the formula, Zs1, Zp1, Zr and Zp2 are the number of teeth of the first sun gear, the first planet gear (23), the gear ring and the second planet gear (23a) respectively; the gear matching scheme is: Zs1=27, Zp1=48, Zr=87 and Zp2=16, i=10.67 can be obtained from formula (1); The reduction ratio achieved by the planetary gear transmission mechanism (20) can be calculated according to formula (1). When going straight, turning and slipping and locking, the planetary gear transmission mechanism (20) can achieve the corresponding reduction ratio. When turning at the center of rotation, the rotating interleaved shaft gear (26) can rotate, the speed of the second sun gear is 0, and the reduction ratio of the planetary gear transmission mechanism (20) is calculated according to formula (2): ； In the formula, Zs2 is the number of teeth of the second sun gear, and Zs2 = 51 is obtained by matching the teeth; i = -4.67 can be obtained from formula (2); This means that the two first motors (11) and the second motor (12) not only have opposite rotation directions, but also have opposite rotation directions to the wheels on the same side, so as to achieve the same right or left center turn.

7. A rear axle electric drive device according to claim 6, characterized in that, For fixed-point steering, the speed relationship between the outer motor and the inner motor is obtained as follows (3): ； In the formula, n2 is the speed of the outer motor and n1 is the speed of the inner motor. According to the gear matching, n2 = 0.3913 n1, that is, the speed directions of the inner and outer motors are the same. The torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor can drive the outer wheel.

8. A rear axle electric drive device according to claim 1, characterized in that, The planetary gear (23) includes a first planetary gear (231) and a second planetary gear (232) that are fixedly connected to each other. The first planetary gear (231) meshes with the sun gear and the first gear ring at the same time. The second planetary gear (232) meshes with the second gear ring. The first gear ring is also provided with bevel teeth that mesh with the bevel gear (26) for transmission. The sun gear serves as the input component (21), the second gear ring serves as the output component (22), the first gear ring serves as the first intermediate component (24), and the planet carrier serves as the second intermediate component (25).

9. A rear axle electric drive device according to claim 8, characterized in that, The reduction ratio achieved by the planetary gear transmission mechanism (20) can be calculated according to formula (4): ； In the formula, Zs, Zr1, Zp1, Zp2 and Zr2 are the number of teeth of the sun gear, the first gear ring, the first planet gear (231), the second planet gear (232) and the second gear ring, respectively; the gear matching scheme is: Zs=16, Zp1=32, Zr1=80, Zp2=16 and Zr2=64; i=16 can be obtained from formula (4); For straight-line, turning, and slip lock-up, the planetary gear transmission mechanism (20) can achieve the corresponding reduction ratio; When turning at the center of rotation, the rotating interleaved shaft gear (26) can rotate, the planetary carrier speed is 0, and the reduction ratio of the planetary gear transmission mechanism (20) is calculated according to formula (5): ； According to equation (5), i = -8 can be obtained.

10. A rear axle electric drive device according to claim 8, characterized in that, For fixed-point steering, the speed relationship between the outer motor and the inner motor is obtained as follows (6): ； In the formula, n2 is the speed of the outer motor and n1 is the speed of the inner motor. According to the gear matching, n2 = 0.3333 n1, that is, the speed directions of the inner and outer motors are the same. The torque direction analysis shows that the torque of the inner motor is negative. Therefore, the inner motor absorbs part of the power during the fixed-point turning process so that the outer motor drives the outer wheel.

Images