Coaxial planetary gearbox two-speed dual-motor independent drive architecture and control strategy

Abstract

This invention belongs to the field of motor drive technology, and more specifically relates to a coaxial planetary gear set two-speed dual-motor independent drive architecture and control strategy. The drive architecture includes coaxial drive motors TM1 and TM2, a double-cascaded planetary gear set, and wet friction brake pad mechanisms B1 and B2. Drive motor TM1 drives the wheels through the two-speed planetary gear set mechanism, while drive motor TM2 directly drives the wheels. This achieves high torque and ultra-high vehicle speed with a small size and lightweight design, greatly increasing the overall vehicle energy efficiency. Furthermore, depending on the vehicle's operating speed, when high torque is required at low, medium, and high speeds, drive motors TM1 and TM2 can drive the wheels simultaneously to achieve rapid acceleration. At ultra-high speeds, drive motor TM2 alone drives the wheels.

Description

Technical Field

[0001] This invention belongs to the field of motor drive technology, and more specifically relates to a coaxial planetary gear set two-speed dual-motor independent drive architecture and control strategy. Background Technology

[0002] Currently, most two-wheeled electric motorcycles, three-wheeled electric motorcycles, and four-wheeled electric passenger vehicles are equipped with single-speed gearboxes, rather than two-speed or multi-speed gearboxes. Single-speed gearboxes have the following main drawbacks:

[0003] 1. Weak acceleration at medium and high speeds: In the medium and high speed range, the drive motor equipped with a single gearbox operates at high speed. The drive motor rotor generates a high back electromotive force, which requires a large field weakening control, resulting in a decrease in drive torque. As a result, the acceleration is insufficient and the maximum speed is limited.

[0004] 2. Low efficiency and low driving range at medium and high speeds: The drive motor operates inefficiently at medium and high speeds, which will greatly reduce the vehicle's driving range.

[0005] 3. Serious NVH and thermal management problems: Under the same operating conditions, the speed of the drive motor will increase, which will aggravate the NVH and thermal management problems of the drive motor and transmission gear shaft system.

[0006] To address the shortcomings of single-gear integrated permanent magnet synchronous motor (IPMSM) assembly systems, two-gear and multi-gear technologies have emerged, offering significant advantages over single-gear systems.

[0007] To increase low-speed climbing ability, the first gear ratio of a two-speed gearbox is greater than that of a single-speed gearbox. This provides greater driving torque for starting and climbing, thus improving low-speed climbing ability.

[0008] To increase the maximum speed, the second gear ratio of a two-speed gearbox should be lower than that of a single-speed gearbox; this will increase the vehicle's maximum speed.

[0009] To improve overall vehicle driving efficiency, switching from the non-economical and inefficient first gear to the economical and efficient second gear in medium and high-speed areas can increase the overall operating efficiency of the powertrain, thereby improving the overall vehicle driving efficiency.

[0010] However, most two-speed and multi-speed gearboxes currently use AMT gearboxes with synchronizers, which have obvious disadvantages such as large size and low maximum speed. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a coaxial planetary gear set two-speed dual-motor independent drive architecture and control strategy, which reduces size, lightens weight, achieves high torque and ultra-high vehicle speed, and greatly increases the overall vehicle energy efficiency.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a coaxial planetary gear set with two gears and dual motors independently driven, comprising a housing, within which drive motors TM1 and TM2, a double-cascaded planetary gear set, and wet friction brake pad mechanisms B1 and B2 are disposed. The output shafts of drive motors TM1 and TM2 are coaxially arranged. The double-cascaded planetary gear set includes a planet carrier C, sun gears S1 and S2, and planet gears P1, P2, and P3. Planet gears P1, P2, and P3 are all rotatably connected to the planet carrier C. S1 connects to the output shaft of drive motor TM1. The sun gear S2 connects to the rotating shaft of wet friction brake pad mechanism B2. Planet gears P1 and P2 are coaxially arranged. Planet gear P1 and sun gear S1 simultaneously mesh with planet gear P3. Planet gear P2 meshes with sun gear S2. An internal gear ring R is provided on the rotating shaft of wet friction brake pad mechanism B1. Planet gear P3 meshes with internal gear ring R. The output shaft of drive motor TM2 connects to planet carrier C. Planet carrier C connects to the wheel outside the housing.

[0013] Furthermore, a piston is sleeved on the rotating shaft of the wet friction brake pad mechanism. The piston is connected to the first friction pad and is slidably connected to the rotating shaft. A second friction pad corresponding to the first friction pad is provided on the outer shell. The piston drives the first friction pad to move to achieve contact or separation with the second friction pad.

[0014] Furthermore, the drive motors TM1 and TM2 are located on the same side of the wheel, and the drive motor TM2 is located on the side of the drive motor TM1 away from the wheel. The output shaft of the drive motor TM1 is a hollow shaft, and the output shaft of the drive motor TM2 passes through the drive motor TM1 and the output shaft of the drive motor TM1.

[0015] Furthermore, the number of teeth of the planetary gears P1, P2 and P3 increases sequentially, and the number of teeth of the sun gear S1 is greater than that of the sun gear S2.

[0016] The drive control strategy of the coaxial planetary gear set two-speed dual-motor independent drive architecture includes two gears. The first gear is used for low-speed driving of the vehicle, and the second gear is used for medium-speed and high-speed driving of the vehicle. At low, medium and high speeds, the drive motor TM1 is driven and the drive motor TM2 stops. When the vehicle reaches ultra-high speed, it is directly driven by TM2 and the drive motor TM1 stops.

[0017] In first gear, the wet friction brake pad mechanism B2 is disengaged, its first and second friction pads separate, allowing the sun gear S2 to rotate. The wet friction brake pad mechanism B1 is engaged, its first and second friction pads contact each other, fixing the internal gear ring R. The drive motor TM1 starts, inputting power through the sun gear S1. The planetary gear P3 rotates on its own axis and revolves around the sun gear S1, thus transmitting power to the planet carrier C. Finally, the power is output to the wheels from the planet carrier C. At this time, the internal gear ring speed nR = 0. Therefore, the first gear reduction ratio formula is:

[0018]

[0019] in, This is the first gear reduction ratio;

[0020] R represents the number of teeth on the internal gear ring.

[0021] The number of teeth on the sun gear S1;

[0022] In second gear, the wet friction brake pad mechanism B1 is disengaged, its first and second friction pads separate, allowing the internal gear ring R to rotate. The wet friction brake pad mechanism B2 is engaged, its first and second friction pads contact each other, fixing the sun gear S2. The drive motor TM1 starts, inputting power through the sun gear S1, then transmitting the power to the planet carrier C via the planet gear P3, and finally outputting it to the wheels from the planet carrier C. At this time, the sun gear speed nS2 = 0. Therefore, the second gear reduction ratio formula is:

[0023]

[0024] in, It has a second gear reduction ratio;

[0025] The number of teeth on the sun gear S1;

[0026] The number of teeth on the sun gear S2;

[0027] This refers to the number of teeth on planetary gear P1.

[0028] This refers to the number of teeth on planetary gear P2.

[0029] Furthermore, when the vehicle requires high torque drive while traveling at low, medium, or high speeds, the drive motor TM2 is activated to assist in driving.

[0030] Furthermore, the vehicle's VCU detects the throttle opening to activate or deactivate the high torque request control, thereby enabling the drive motor TM2 to be engaged or disengaged.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: by arranging drive motors TM1 and TM2 coaxially, drive motor TM1 drives the wheels through a planetary gear set two-speed mechanism, and drive motor TM2 directly drives the wheels, thereby achieving high torque and ultra-high vehicle speed with small size and light weight, greatly increasing the energy efficiency of the whole vehicle; it can also drive the wheels simultaneously through drive motors TM1 and TM2 when high torque is required at low speed, medium speed and high speed, to achieve rapid acceleration, while drive motor TM2 alone drives the wheels at ultra-high speed. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the coaxial planetary gear set two-speed dual-motor independent drive architecture of the present invention;

[0033] Figure 2 This is a control strategy diagram of the coaxial planetary gear set two-speed dual-motor independent drive architecture of the present invention. Detailed Implementation

[0034] In the description of this invention, it should be noted that the directional terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In the description of this invention, "several" or "a number" means two or more, unless otherwise explicitly specified.

[0036] Reference Figure 1 and Figure 2 The present invention will be further described below.

[0037] A coaxial planetary gear set with two speeds and dual motors, independently driven, includes a housing. Inside the housing are drive motors TM1 and TM2, a dual-cascade planetary gear set, and wet friction brake pad mechanisms B1 and B2. The output shafts of drive motors TM1 and TM2 are coaxially arranged. The dual-cascade planetary gear set includes a planet carrier C, sun gears S1 and S2, and planet gears P1, P2, and P3. Planet gears P1, P2, and P3 are rotatably connected to the planet carrier C. Sun gear S1 is connected to the output shaft of drive motor TM1, and sun gear S2 is connected to the rotating shaft of wet friction brake pad mechanism B2. Planet gears P1 and P2 are coaxially arranged. Planet gear P1 and sun gear S1 simultaneously mesh with planet gear P3, and planet gear P2 meshes with sun gear S2. An internal gear ring R is mounted on the rotating shaft of wet friction brake pad mechanism B1, and planet gear P3 meshes with the internal gear ring R. The output shaft of drive motor TM2 is connected to the planet carrier C, and the planet carrier C is connected to a wheel outside the housing.

[0038] like Figure 1 As shown in the example, in the preferred embodiment, a piston is sleeved on the rotating shaft of the wet friction brake pad mechanism, the piston is connected to the first friction pad, the piston is slidably connected to the rotating shaft, and a second friction pad corresponding to the first friction pad is provided on the outer shell. The piston drives the first friction pad to move to achieve contact or separation with the second friction pad.

[0039] The specific structure of the wet friction brake pad mechanism is existing technology. For reference, please refer to the existing patent technology with publication number CN218367253U entitled "A Wet Braking Wheel Side of Drive Axle" or the existing patent technology with publication number CN118810418A entitled "Wet Braking Wheel Side Reduction Assembly and New Energy Transmission Equipment". It will not be described again in this example.

[0040] like Figure 1 As shown, in this example, preferably, the drive motors TM1 and TM2 are located on the same side of the wheel, and the drive motor TM2 is located on the side of the drive motor TM1 away from the wheel. The output shaft of the drive motor TM1 is a hollow shaft, and the output shaft of the drive motor TM2 passes through the drive motor TM1 and the output shaft of the drive motor TM1.

[0041] like Figure 1 As shown, in this example, preferably, the number of teeth of the planetary gears P1, P2 and P3 increases sequentially, that is, the number of teeth is: planetary gear P3 > planetary gear P2 > planetary gear P1, and the number of teeth of the sun gear S1 is greater than that of the sun gear S2.

[0042] like Figure 1 As shown, by arranging drive motors TM1 and TM2 coaxially, drive motor TM1 drives the wheels through a two-speed planetary gear set, while drive motor TM2 directly drives the wheels. This achieves high torque and ultra-high speed with a small size and lightweight design, greatly increasing the overall vehicle energy efficiency. Furthermore, depending on the vehicle's operating speed, when high torque is required at low, medium, and high speeds, drive motors TM1 and TM2 can be used simultaneously to drive the wheels, enabling rapid acceleration. At ultra-high speeds, drive motor TM2 alone provides the driving capability.

[0043] The control strategy of the coaxial planetary gear set two-speed dual-motor independent drive architecture includes two speeds: the first speed is used for low-speed driving, and the second speed is used for medium and high-speed driving. At low, medium, and high speeds, drive motor TM1 is used, while drive motor TM2 is stopped. When the vehicle reaches ultra-high speeds, TM2 is used directly, and drive motor TM1 is stopped, as shown in the control strategy table below:

[0044]

[0045] In this context, “〇” represents running and “×” represents stopping.

[0046] Specifically, the low-speed range is 0-40km / h, and vehicles mostly travel on roads within residential areas, congested urban roads, school zones, parking lots, and when starting and reversing.

[0047] The medium speed range is 40-80km / h, and vehicles mostly travel on urban main roads, ordinary national highways, suburban roads, and in situations where they are driving slowly alongside other vehicles.

[0048] The high-speed range is 80-140 km / h, and vehicles mostly travel on highways and urban expressways.

[0049] Ultra-high speeds are greater than 140 km / h and are typically used in situations such as track driving, unrestricted highways abroad, and high-performance vehicle testing.

[0050] In first gear, the wet friction brake pad mechanism B2 is disengaged, its first and second friction pads separate, allowing the sun gear S2 to rotate. The wet friction brake pad mechanism B1 is engaged, its first and second friction pads contact each other, fixing the internal gear ring R. The drive motor TM1 starts, inputting power through the sun gear S1. The planetary gear P3 rotates on its own axis and revolves around the sun gear S1, thus transmitting power to the planet carrier C. Finally, the power is output to the wheels from the planet carrier C. At this time, the rotational speed nR of the internal gear ring R is 0. Therefore, the first gear reduction ratio formula is:

[0051]

[0052] in, This is the first gear reduction ratio;

[0053] R represents the number of teeth on the internal gear ring.

[0054] The number of teeth on the sun gear S1;

[0055] In second gear, the wet friction brake pad mechanism B1 is disengaged, and its first and second friction pads separate, allowing the internal gear ring R to rotate. The wet friction brake pad mechanism B2 is engaged, and its first and second friction pads contact each other, fixing the sun gear S2. The drive motor TM1 starts, inputting power through the sun gear S1, then transmitting the power to the planet carrier C via the planet gear P3, and finally outputting it to the wheels from the planet carrier C. At this time, the rotational speed of the sun gear S2, nS2 = 0. Therefore, the second gear reduction ratio formula is:

[0056]

[0057] in, It has a second gear reduction ratio;

[0058] The number of teeth on the sun gear S1;

[0059] The number of teeth on the sun gear S2;

[0060] This refers to the number of teeth on planetary gear P1.

[0061] This refers to the number of teeth on planetary gear P2.

[0062] like Figure 2 As shown in this example, when the vehicle needs high torque drive while traveling at low, medium or high speed, the drive motor TM2 is started to assist in driving. Specifically, high torque situations generally include starting acceleration at low speed, such as starting from a standstill or climbing a steep slope; needing to accelerate rapidly to overtake at medium speed, such as overtaking slower vehicles on urban roads or merging into the main road at a highway entrance; and accelerating again at high speed to quickly overtake the vehicle in front.

[0063] In this example, the preferred method is to use the vehicle's VCU to detect the throttle opening to activate or deactivate the high torque request control, thereby enabling the drive motor TM2 to be engaged or disengaged. Specifically, it can be set that the drive motor TM2 is engaged when the throttle opening is ≥80%, and disengaged otherwise.

[0064] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A coaxial planetary gearbox with two speeds and dual independent motor drive architecture, characterized in that: The device includes a housing, within which are housed drive motors TM1 and TM2, a double-cascaded planetary gear set, and wet friction brake pad mechanisms B1 and B2. The output shafts of drive motors TM1 and TM2 are coaxially arranged. The double-cascaded planetary gear set includes a planet carrier C, sun gears S1 and S2, and planet gears P1, P2, and P3. Planet gears P1, P2, and P3 are rotatably connected to the planet carrier C. The sun gear S1 is connected to the output shaft of drive motor TM1, and the sun gear S2 is connected to the rotating shaft of wet friction brake pad mechanism B2. Planet gears P1 and P2 are coaxially arranged, and planet gear P1 and sun gear S1 simultaneously mesh with planet gear P3. Planet gear P2 meshes with sun gear S2. An internal gear ring R is provided on the rotating shaft of wet friction brake pad mechanism B1, and planet gear P3 meshes with the internal gear ring R. The output shaft of drive motor TM2 is connected to the planet carrier C, and the planet carrier C is connected to a wheel outside the housing. The drive motors TM1 and TM2 are located on the same side of the wheel, and drive motor TM2 is located on the side of drive motor TM1 away from the wheel. The output shaft of drive motor TM1 is a hollow shaft, and the output shaft of drive motor TM2 passes through drive motor TM1 and the output shaft of drive motor TM1.

2. The coaxial planetary gearbox two-speed dual-motor independent drive architecture according to claim 1, characterized in that: A piston is sleeved on the rotating shaft of the wet friction brake pad mechanism. The piston is connected to the first friction pad and is slidably connected to the rotating shaft. A second friction pad corresponding to the first friction pad is provided on the outer shell. The piston drives the first friction pad to move to achieve contact or separation with the second friction pad.

3. The coaxial planetary gearbox two-speed dual-motor independent drive architecture according to claim 1, characterized in that: The number of teeth on planetary gears P1, P2, and P3 increases sequentially, and the number of teeth on sun gear S1 is greater than that on sun gear S2.

4. A drive control strategy, using the coaxial planetary gearbox two-speed dual-motor independent drive architecture as described in any one of claims 1-3, characterized in that: It includes two gears. The first gear is used for low-speed driving, and the second gear is used for medium-speed and high-speed driving. At low, medium and high speeds, the drive motor TM1 is used, and the drive motor TM2 stops. When the vehicle reaches ultra-high speed, it is directly driven by TM2, and the drive motor TM1 stops. In first gear, the wet friction brake pad mechanism B2 is disengaged, its first and second friction pads separate, allowing the sun gear S2 to rotate. The wet friction brake pad mechanism B1 is engaged, its first and second friction pads contact each other, fixing the internal gear ring R. The drive motor TM1 starts, inputting power through the sun gear S1. The planetary gear P3 rotates on its own axis and revolves around the sun gear S1, thus transmitting power to the planet carrier C. Finally, the power is output to the wheels from the planet carrier C. At this time, the internal gear ring speed nR = 0. Therefore, the first gear reduction ratio formula is: in, This is the first gear reduction ratio; R represents the number of teeth on the internal gear ring. The number of teeth on the sun gear S1; In second gear, the wet friction brake pad mechanism B1 is disengaged, its first and second friction pads separate, allowing the internal gear ring R to rotate. The wet friction brake pad mechanism B2 is engaged, its first and second friction pads contact each other, fixing the sun gear S2. The drive motor TM1 starts, inputting power through the sun gear S1, then transmitting the power to the planet carrier C via the planet gear P3, and finally outputting it to the wheels from the planet carrier C. At this time, the sun gear speed nS2 = 0. Therefore, the second gear reduction ratio formula is: in, It has a second gear reduction ratio; The number of teeth on the sun gear S1; The number of teeth on the sun gear S2; This refers to the number of teeth on planetary gear P1. This represents the number of teeth on planetary gear P2.

5. The control strategy according to claim 4, characterized in that: When the vehicle requires high torque drive while traveling at low, medium or high speeds, the drive motor TM2 is activated to assist in driving.

6. The control strategy according to claim 5, characterized in that: The vehicle's VCU detects the throttle opening to activate or deactivate high torque request control, thereby enabling the drive motor TM2 to be engaged or disengaged.

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