Double planetary row electric drive system, vehicle and gear shifting method

Abstract

The application belongs to the technical field of electric drive systems, and particularly relates to a double-planetary-row electric drive system, a vehicle and a gear shifting method. The electric drive system comprises a gearbox housing, a first motor, a second motor, a first planetary row, a second planetary row, a connecting device and a system output shaft. The first planetary row comprises a first sun gear, a first ring gear and a first carrier, and the second planetary row comprises a second sun gear, a second ring gear and a second carrier. The rotor of the first motor is connected with the second sun gear, and the rotor of the second motor is connected with the first sun gear. The first carrier is connected with the second ring gear. The second carrier is connected with the first ring gear and the system output shaft. The connecting device is used for fixedly connecting the first carrier with the gearbox housing or fixedly connecting the first carrier with the first ring gear. The double-planetary-row electric drive system can realize uninterrupted power supply of the vehicle during gear shifting, thereby improving the performance of the electric vehicle.

Description

Technical Field

[0001] This invention belongs to the field of electric drive system technology, specifically relating to a dual planetary gear electric drive system, a vehicle, and a shifting method. Background Technology

[0002] Electric vehicles are new, energy-saving, and environmentally friendly vehicles, and especially in today's environment of severe air pollution, they have enormous development potential and broad application prospects. Electric vehicles use electric motors to replace the engines of traditional cars. Electric motors can start under load and, through reasonable configuration, can meet the usage requirements of vehicles under different operating conditions—a key difference from engines.

[0003] Using multi-speed transmissions in electric vehicles is no longer suitable. However, eliminating the transmission mechanism makes it difficult to meet the requirements of climbing hills and high-speed driving, especially for small and medium-sized cars. It is necessary to redesign the power system of electric vehicles to take into account the operating characteristics of electric motors. Currently, most electric vehicles use dual planetary gear electric drive systems. However, the existing dual planetary gear electric drive systems are constant-ratio drive systems without gear function, so they cannot simultaneously achieve maximum speed and high torque output.

[0004] The existing AMT (Automated Manual Transmission) shifting process is divided into five stages: torque clearing, disengaging, speed adjustment, shifting up, and torque return. Torque clearing refers to removing the drive torque from the system's output shaft, while torque return refers to reapplying torque to the system's output shaft. During the shifting process, from the torque clearing stage to the torque return stage, the power system inevitably experiences a power interruption. For example, the two-speed AMT electric vehicle shifting method disclosed in Chinese invention patent specification CN110886838B requires removing the torque from the AMT input shaft (torque clearing) before disengaging from first to second gear, which leads to a power interruption in the electric vehicle. Summary of the Invention

[0005] The purpose of this invention is to provide a dual planetary gear electric drive system that can achieve uninterrupted power during gear shifting; it also provides a vehicle to solve the problems of jerking and poor driving experience caused by power interruption during gear shifting; and it also provides a gear shifting method to solve the technical problem of power interruption during gear shifting in a dual planetary gear electric drive system.

[0006] To address the aforementioned technical problems, this invention provides a dual planetary gearbox electric drive system that enables uninterrupted power transmission during gear shifting through controlled operation. The system includes a gearbox housing, a first motor, a second motor, a first planetary gearbox, a second planetary gearbox, a connecting device, and a system output shaft. The first planetary gearbox includes a first sun gear, a first ring gear, and a first planet carrier. The second planetary gearbox includes a second sun gear, a second ring gear, and a second planet carrier. The rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear. The first planet carrier is connected to the second ring gear. The second planet carrier is connected to both the first ring gear and the system output shaft. The connecting device is used to fix the first planet carrier to the gearbox housing or to the first ring gear.

[0007] The beneficial effects are as follows: The dual planetary gear electric drive system of the present invention operates in first gear when the first planetary carrier is fixedly connected to the gearbox housing, and in second gear when the first planetary carrier is fixedly connected to the first ring gear. Since the rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear; the first planetary carrier is connected to the second ring gear; and the second planetary carrier is connected to both the first ring gear and the system output shaft, during gear shifting, the first motor can continue to drive the system output shaft. The torque of the second motor is adjusted so that the difference between the torque exerted by the first motor on the system output shaft and the torque exerted by the second motor on the system output shaft is less than a first calibration value, and the gear is disengaged. After disengaging, the torque of the first motor remains unchanged, and the torque of the second motor is adjusted so that the difference between the rotational speed of the first planetary carrier and the rotational speed of the first planetary gear ring is less than a second calibration value, and the first planetary carrier is fixedly connected to the gearbox housing, thus completing the gear shift. Throughout the entire first-gear to second-gear shifting process, the system output shaft is continuously driven by the motor, and the power is not interrupted. The dual planetary gear electric drive system of the present invention can ensure that the vehicle's power is not interrupted during gear shifting, thereby improving the performance of electric vehicles.

[0008] Preferably, the connecting device includes a coupling tooth fixed on the gearbox housing and an outer coupling tooth connected to the first planetary carrier, as well as a gear sleeve for fixing the coupling tooth to the outer coupling tooth in a first position or fixing the outer coupling tooth to the first gear ring in a second position, and controlling the gear sleeve to switch between the first position and the second position by a gear shifting device.

[0009] Preferably, the connecting device includes a first clutch and a second clutch, wherein the two ends of the first clutch that are engaged or disengaged are respectively disposed on the gearbox housing and the first planetary carrier; the two ends of the second clutch that are engaged or disengaged are respectively disposed on the first planetary carrier and the first ring gear; the engagement of the first clutch and the disengagement of the second clutch or the disengagement of the first clutch and the engagement of the second clutch are controlled by the gear shifting device.

[0010] Preferably, a first motor, a second motor, a first planetary gear set, and a second planetary gear set are arranged sequentially from front to back inside the gearbox housing. The output shaft of the first motor freely passes through the hollow output shaft of the second motor and connects to the sun gear of the second planetary gear set. The hollow rotor of the second motor is connected to the sun gear of the first planetary gear set. Alternatively, a second motor, a first planetary gear set, a second planetary gear set, and a first motor are arranged sequentially from front to back inside the gearbox housing. The output shaft of the system passes through the hollow output shaft of the first motor and outputs power to the drive axle at the rear of the gearbox housing.

[0011] Its beneficial effects are as follows: by integrating the first motor, the second motor, the first planetary gear set, and the second planetary gear set into the gearbox housing, a high degree of integration is achieved, the product size is reduced, the power system is easier to arrange, and the transmission efficiency of the system is improved.

[0012] To address the aforementioned technical problems, the present invention also provides a shifting method for a dual planetary gear electric drive system based on the present invention, comprising the following steps:

[0013] Control the working state of the first motor and the second motor so that the first motor drives the system output shaft independently and meets the torque required by the driver. Adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value.

[0014] When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation;

[0015] After disengaging from gear, maintain the torque of the first motor unchanged, and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value.

[0016] When the speed difference between the first planetary carrier and the first ring gear is less than the second calibration value, the second connecting device connects the first planetary carrier and the first ring gear together, thereby completing the gear shift.

[0017] Its beneficial effects are as follows: When using the shifting method of the present invention, shifting can be achieved without removing the torque on the system output shaft when shifting from first gear to second gear, thus avoiding the problem of power interruption; the shifting method of the present invention based on the dual planetary gear electric drive system can ensure that the power of the electric vehicle is not interrupted during the shifting from first gear to second gear, thereby making the electric vehicle perform better.

[0018] Preferably, in step 1), the first motor independently drives the system output shaft and provides the output torque required by the driver. for:

[0019] ;

[0020] In the formula, For the torque required by the driver, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. It is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear.

[0021] Preferably, in step 1), the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value of the output torque of the second motor. for:

[0022] ;

[0023] In the formula, For the torque required by the driver, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. It is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear.

[0024] Preferably, in step 3), in order to ensure that the difference between the rotational speed of the first planetary carrier and the rotational speed of the first planetary gear ring is less than the second calibration value, the second target torque that the second motor needs to output... for:

[0025] ;

[0026] In the formula, The torque of the first motor, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. This is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear. This indicates that based on the speed difference between the first planetary carrier and the first ring gear... The corrected torque for the second target torque obtained through calculation.

[0027] To address the aforementioned technical problems, the present invention also provides an electric drive vehicle that can achieve uninterrupted power during gear shifting through certain control, including the electric drive system of the present invention.

[0028] Its beneficial effects are as follows: The electric drive system of the electric drive vehicle of the present invention operates in first gear when the first planetary carrier is fixedly connected to the gearbox housing, and in second gear when the first planetary carrier is fixedly connected to the first ring gear; since the rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear; the first planetary carrier is connected to the second ring gear; and the second planetary carrier is connected to the first ring gear and the output shaft respectively; during gear shifting, the first motor can continue to drive the system output shaft, and the torque of the second motor can be adjusted so that the torque of the first motor acting on the system output shaft is equal to the torque of the second motor acting on the system output shaft. When the torque difference on the output shaft is less than the first calibration value, the gear is disengaged. After disengagement, the torque of the first motor is kept constant, and the torque of the second motor is adjusted so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value. The first planetary carrier is then fixedly connected to the gearbox housing, thereby completing the gear shift. Throughout the entire gear shifting process, the system output shaft is continuously driven by the motor, and the power is not interrupted. The electric drive vehicle using this invention can ensure that the vehicle's power is not interrupted during the shift from first gear to second gear, thereby solving the problem of jerking and poor driving experience caused by power interruption during gear shifting.

[0029] Preferably, the vehicle achieves gear shifting through the following method:

[0030] Control the working state of the first motor and the second motor so that the first motor drives the system output shaft independently and meets the torque required by the driver. Adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value.

[0031] When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation;

[0032] After disengaging from gear, maintain the torque of the first motor unchanged, and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value.

[0033] When the speed difference between the first planetary carrier and the first planetary ring gear is less than the second calibration value, the first planetary carrier and the first ring gear are fixedly connected together by a connecting device, thereby completing the gear shift. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the first embodiment of the dual planetary gear electric drive system of the present invention;

[0035] Figure 2 This is a schematic diagram of the second embodiment of the dual planetary gear electric drive system of the present invention;

[0036] Figure 3 This is a flowchart of the shifting method steps of the present invention;

[0037] Figure 4 This is a schematic diagram of the lever analysis of a planetary array;

[0038] Figure 5 This is a schematic diagram of the third embodiment of the dual planetary gear electric drive system of the present invention in Embodiment 2;

[0039] Figure 6 This is a schematic diagram of the fourth embodiment of the dual planetary gear electric drive system of the present invention, in Embodiment 2.

[0040] Explanation of reference numerals in the attached drawings: 1 is the gearbox housing; 2 is the first motor; 3 is the second motor; 4 is the engagement gear; 5A is the first planetary carrier; 5B is the first ring gear; 5C is the first sun gear; 6A is the second planetary carrier; 6B is the second ring gear; 6C is the second sun gear; 7 is the system output shaft; 4A is the first clutch; 4B is the second clutch. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of this invention.

[0042] Example 1 of a dual planetary gear electric drive system:

[0043] like Figure 1 and Figure 2As shown, the dual planetary gear electric drive system of the present invention includes a gearbox housing 1, a first motor 2, a second motor 3, a first planetary gear set, a second planetary gear set, a gear shifting device (not shown in the figure), a system output shaft 7, and a connecting device for fixing the first planetary carrier 5A to the gearbox housing, or fixing the first planetary carrier 5A to the first gear ring 5B. The connecting device includes a gear engagement tooth 4 and a gear sleeve (not shown in the figure) disposed on the gearbox housing 1, as well as an outer gear engagement tooth disposed on the first planetary carrier 5A and an outer gear engagement tooth disposed on the first gear ring 5B. By pushing the gear sleeve through the gear shifting device, the gear engagement tooth 4 and the outer gear engagement tooth on the first planetary carrier 5A can be fixedly connected through the gear sleeve, or the outer gear engagement tooth on the first planetary carrier 5A and the outer gear engagement tooth on the first gear ring 5B can be fixedly connected through the gear sleeve.

[0044] The first planetary gear set includes a first sun gear 5C, a first ring gear 5B, and a first planetary carrier 5A; the second planetary gear set includes a second sun gear 6C, a second ring gear 6B, and a second planetary carrier 6A; the first motor 2 includes a first motor rotor 2A; the second motor 3 includes a second motor rotor 3A; an external engagement tooth is provided on the first planetary carrier 5A so as to be fixedly connected by a tooth sleeve and engagement tooth 4 or the first ring gear 5B.

[0045] Specifically, it can be as follows: Figure 1 As shown, inside the gearbox housing, from front to back, a first motor 2, a second motor 3, a first planetary gear set, and a second planetary gear set are arranged sequentially. The output shaft of the first motor freely passes through the hollow output shaft of the second motor and connects to the sun gear (i.e., the second sun gear 6C) of the second planetary gear set. The hollow output shaft of the second motor is connected to the sun gear (i.e., the first sun gear 5C) of the first planetary gear set. At the same time, the first planetary carrier 5A is connected to the second ring gear 6B, and the first ring gear 5B is connected to the second planetary carrier 6A.

[0046] Or it could be like Figure 2 As shown, inside the gearbox housing, from front to back, a second motor 3, a first planetary gear set, a second planetary gear set, and a first motor 2 are arranged sequentially. The system output shaft 7 passes through the hollow first motor output shaft and outputs power to the drive axle outside the rear of the gearbox housing. The first motor 2, the second motor 3, and the engagement gear 4 are all fixedly connected to the gearbox housing 1. The second motor rotor 3A is connected to the first sun gear 5C, and the first motor rotor 2A is connected to the second sun gear 6C. The first planetary carrier 5A is connected to the second ring gear 6B. The second planetary carrier 6A is connected to the first ring gear 5B and the system output shaft 7. The first motor 2, the second motor 3, the first planetary gear set, and the second planetary gear set are all located inside the gearbox housing.

[0047] The system output shaft 7 of the present invention is connected to the second planetary carrier 6A. Since the second planetary carrier 6A is connected to the first gear ring 5B, it can also be understood that the system output shaft 7 of the present invention is connected to the first gear ring 5B.

[0048] by Figure 1 Taking the drive system configuration shown as an example, the working principle and process of the dual planetary gear electric drive system in this embodiment are as follows:

[0049] The working principle of the first gear constant speed ratio drive mode is as follows: The external engagement gear on the first planetary carrier 5A is fixedly connected to the engagement gear 4 via a gear sleeve using a gear shifting device. At this time, the first planetary carrier 5A and the second ring gear 6B are simultaneously locked onto the gearbox housing 1. The first motor 2 and the second motor 3 can simultaneously output torque to drive the system output shaft 7, or output torque separately to drive the system output shaft 7. After the first planetary carrier 5A, the second ring gear 6B, and the engagement gear 4 are engaged by the gear shifting device, the torque direction and rotational speed direction of the first motor rotor 2A are the same as those of the system output shaft 7, while the torque direction and rotational speed direction of the second motor rotor 3A are opposite to those of the system output shaft 7.

[0050] When the first motor 2 is driven alone, the torque output by the system output shaft 7 is expressed as follows:

[0051] (1)

[0052] When the second motor 3 is driven alone, the torque output by the system output shaft 7 is expressed as follows:

[0053] (2)

[0054] When the first motor 2 and the second motor 3 are driven simultaneously, the torque output by the system output shaft 7 is expressed as follows:

[0055] (3)

[0056] In equations (1) to (3), This is the ratio of the number of teeth on the first gear ring 5B to the number of teeth on the first sun gear 5C. It is the ratio of the number of teeth of the second gear ring 6B to the number of teeth of the second sun gear 6C; The output torque of the system output shaft 7, This is the actual torque of the first motor 2. This is the actual torque of the second motor 3.

[0057] In this embodiment, the output shaft of the dual planetary gear electric drive system can be driven by either the first motor 2 or the second motor 3 alone, or by both motors simultaneously. On smooth roads, when the torque required by the system output shaft is low, only one motor can be used to drive it, reducing energy consumption. On uphill roads, when the torque required by the system output shaft is high, both motors can be used to drive it simultaneously, increasing vehicle power. This allows the electric vehicle to save power while ensuring functional performance.

[0058] The working principle of the two-speed constant ratio drive mode is as follows: the external engagement gear on the first planetary carrier 5A is fixedly connected to the first gear ring 5B by the gear sleeve using the gear shifting device. That is, the first planetary carrier 5A and the second gear ring 6B are locked together with the first gear ring 5B and the second planetary carrier 6A. The two planetary sets are locked into a whole. At this time, the system is equivalent to a constant speed ratio transmission system with a speed ratio of 1. The torque direction and speed direction of the first motor rotor 2A and the second motor rotor 3A are the same as the torque direction and speed direction of the system output shaft 7.

[0059] When the first motor 2 is driven alone, the torque output by the system output shaft 7 is expressed as follows:

[0060] (4)

[0061] When the second motor 3 is driven alone, the torque output by the system output shaft 7 is expressed as follows:

[0062] (5)

[0063] When the first motor 2 and the second motor 3 are driven simultaneously, the torque output by the system output shaft 7 is expressed as follows:

[0064] (6)

[0065] In equations (4) to (6), The output torque of the system output shaft 7, This is the actual torque of the first motor 2. This is the actual torque of the second motor 3.

[0066] The gear shifting process includes shifting from first gear to second gear and shifting from second gear to first gear, such as... Figure 3 As shown, the process of shifting from first to second gear is as follows:

[0067] S1: The system output shaft torque is maintained by driving the first motor 2 alone and the torque required by the driver is met. The torque of the second motor 3 is adjusted in real time so that the difference between the torque of the first motor 2 acting on the system output shaft 7 and the torque of the second motor 3 acting on the system output shaft 7 is less than the first calibration value.

[0068] During gear shifting, if both motors are simultaneously on the output shaft of the drive system or the second motor is on the output shaft of the drive system alone, the working state of the first motor and the second motor is controlled by the motor control device, so that the first motor drives the output shaft of the drive system alone.

[0069] The condition for disengaging gears is met when the difference between the torque exerted by the first motor on the system output shaft and the torque exerted by the second motor on the system output shaft is less than the first calibration value.

[0070] The torque exerted by the first motor on the system output shaft in real time is: (7)

[0071] The torque exerted by the second motor on the system output shaft in real time is: (8)

[0072] In equations (7) to (8), This is the actual torque of the first motor 2. This is the actual torque of the second motor 3.

[0073] The torque required by the driver is equal to the sum of the output torque of the first motor 2 and the output torque of the second motor 3, as expressed below:

[0074] (9)

[0075] The first motor independently drives the output shaft of the system and provides the required torque for the driver. for:

[0076] (10)

[0077] The output torque of the second motor is such that the difference between the torque exerted by the first motor on the system output shaft and the torque exerted by the second motor on the system output shaft is less than the first calibration value. for:

[0078] (11)

[0079] In equations (7) to (11), For the torque required by the driver, This is the ratio of the number of teeth on the first gear ring 5B to the number of teeth on the first sun gear 5C. This is the ratio of the number of teeth on the second gear ring 6B to the number of teeth on the second sun gear 6C. This is the actual torque of the first motor 2. This is the actual torque of the second motor 3.

[0080] The real-time torque of the second motor 3 can be based on, for example... Figure 4 The calculation is performed using the lever analysis diagram of the planetary array shown.

[0081] S2: When the difference between the torque of the first motor 2 acting on the system output shaft 7 and the torque of the second motor 3 acting on the system output shaft 7 is less than the first calibration value, the engagement gear 4 and the first planetary carrier 5A are separated by the gear engagement device to complete the gear disengagement operation.

[0082] S3: After disengaging the gear, maintain the torque of the first motor 2 at [value missing]. Without changing the speed, adjust the torque of the second motor 3 so that the difference between the speed of the first planetary carrier 5A and the speed of the first gear ring 5B (i.e., the second planetary carrier 6A) is less than the second calibration value.

[0083] Based on the speed difference between the first planetary carrier 5A and the first ring gear 5B, and the torque of the first motor 2, it can be deduced that in order to make the speed difference between the first planetary carrier 5A and the first ring gear 5B less than the second calibration value, the second target torque that the second motor 3 needs to output is... for:

[0084] (12)

[0085] = (13)

[0086] In equations (12) and (13), The torque of the first motor, This is the ratio of the number of teeth on the first gear ring 5B to the number of teeth on the first sun gear 5C. This is the ratio of the number of teeth on the second gear ring 6B to the number of teeth on the second sun gear 6C. This indicates that based on the speed difference between the first planetary carrier 5A and the first ring gear 5B The second target torque obtained by calculation The corrected target torque, The proportional term is used to calculate the target torque. The integral term is the target torque calculation, and t is the time spent adjusting the torque of the second motor 3 in step S3.

[0087] After the torque output by the second motor 3 is adjusted to the second target torque of the second motor 3, the speed difference between the first planetary carrier 5A and the first gear ring 5B begins to decrease rapidly.

[0088] S4: When the speed difference between the first planetary carrier 5A and the first ring gear 5B is less than the calibrated value, the first planetary carrier 5A, the first ring gear 5B, the second planetary carrier 6A and the second ring gear 6B can be connected together through the gear shifting device to complete the gear shifting.

[0089] After shifting into second gear, the two motors are controlled to restore normal torque.

[0090] Example 2 of a dual planetary gear electric drive system:

[0091] like Figure 5 and Figure 6As shown, the dual planetary gear electric drive system in this embodiment replaces the engagement gear and shifting device in the dual planetary gear electric drive system of Embodiment 1 with a first clutch 4A and a second clutch 4B. The two ends of the first clutch 4A that are engaged or disengaged are respectively located on the gearbox housing 1 and the first planetary carrier 5A; the two ends of the second clutch 4B that are engaged or disengaged are respectively located on the first planetary carrier 5A and the first ring gear 5B. The shifting device controls the engagement of the first clutch 4A and the disengagement of the second clutch 4B, or the disengagement of the first clutch 4A and the engagement of the second clutch 4B, to achieve two-gear switching. The other parts of the dual planetary gear electric drive system in this embodiment are the same as those in Embodiment 1.

[0092] In this embodiment, the dual planetary gear electric drive system, when engaged in first gear, uses the first clutch 4A to fix the first planetary carrier 5A to the gearbox housing 1; when engaged in second gear, it uses the second clutch 4B to fix the first planetary carrier 5A and the first ring gear 5B. Except for the gear engagement method, the working principle, process, and technical effects of the dual planetary gear electric drive system in this embodiment are the same as those in Embodiment 1, and will not be repeated here.

[0093] The dual planetary gearbox electric drive system of this invention ensures that the system output shaft is continuously driven by the motor throughout the entire first-to-second-gear shift process, preventing power interruption. This system guarantees uninterrupted vehicle power during gear shifts, resulting in improved vehicle performance. By integrating the first motor, second motor, first planetary gearbox, and second planetary gearbox within the gearbox housing, high integration is achieved, reducing product size, facilitating powertrain layout, and improving system transmission efficiency. Furthermore, the dual planetary gearbox electric drive system of this invention solves the problems of jerking and poor driving experience caused by power interruption during gear shifts in electric vehicles.

[0094] Example of a shifting method based on a dual planetary gear electric drive system:

[0095] The shifting method based on a dual planetary gear electric drive system of the present invention includes a first-gear constant speed ratio drive method, a second-gear constant speed ratio drive method, and a first-gear to second-gear shifting method; the first-gear to second-gear shifting method includes the following steps:

[0096] Control the working state of the first motor and the second motor so that the first motor drives the system output shaft independently and meets the torque required by the driver. Adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value.

[0097] When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation;

[0098] After disengaging from gear, maintain the torque of the first motor unchanged, and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value.

[0099] When the speed difference between the first planetary carrier and the first ring gear is less than the second calibration value, the first planetary carrier and the first ring gear are connected together through the connecting device, thereby completing the gear shift.

[0100] The shifting method of this invention allows for shifting without removing torque from the system output shaft when changing from first to second gear, thus avoiding power interruption. Furthermore, the shifting method based on the dual planetary gear electric drive system of this invention ensures uninterrupted power during the shift from first to second gear, resulting in improved electric vehicle performance.

[0101] The specific details and technical effects of the driving method of the dual planetary gear electric drive system of the present invention have been described in the embodiments of the dual planetary gear electric drive system, and will not be repeated here.

[0102] Examples of electric drive vehicles:

[0103] The electric drive vehicle of the present invention includes a vehicle body and an electric drive system. The electric drive system includes a gearbox housing, a first motor, a second motor, a first planetary gear set, a second planetary gear set, a first connecting device, a second connecting device, and a system output shaft. The first planetary gear set includes a first sun gear, a first ring gear, and a first planet carrier; the second planetary gear set includes a second sun gear, a second ring gear, and a second planet carrier. The rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear. The first planet carrier is connected to the second ring gear. The second planet carrier is connected to both the first ring gear and the system output shaft. The first connecting device is used to fix the first planet carrier to the gearbox housing, and the second connecting device is used to fix the first planet carrier to the first ring gear. The working principle, working process, and technical effects of the electric drive vehicle of the present invention have been described in the embodiments of the dual planetary gear electric drive system and will not be repeated here.

Claims

1. A dual planetary gear electric drive system, characterized in that, The system includes a gearbox housing, a first motor, a second motor, a first planetary gear set, a second planetary gear set, a connecting device, and a system output shaft. The first planetary gear set includes a first sun gear, a first ring gear, and a first planet carrier. The second planetary gear set includes a second sun gear, a second ring gear, and a second planet carrier. The rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear. The first planet carrier is connected to the second ring gear, and the second planet carrier is connected to both the first ring gear and the system output shaft. The connecting device is used to fix the first planet carrier to the gearbox housing to achieve first gear, or to fix the first planet carrier to the first ring gear to lock the two planetary gear sets into a single unit with a speed ratio of 1 for second gear. The dual planetary gear set electric drive system achieves first-gear shifting to second gear through the following steps: 1) Control the working state of the first motor and the second motor, so that the first motor drives the system output shaft alone and meets the torque required by the driver, and adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value. 2) When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation; 3) After disengaging the gear, keep the torque of the first motor constant and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value. 4) When the speed difference between the first planetary carrier and the first ring gear is less than the second calibration value, the first planetary carrier and the first ring gear are connected together through the connecting device, thereby completing the gear shift.

2. The dual planetary gear electric drive system as described in claim 1, characterized in that, The connecting device includes a coupling tooth fixed on the gearbox housing and an outer coupling tooth connected to the first planetary carrier, as well as a gear sleeve for fixing the coupling tooth to the outer coupling tooth in a first position or fixing the outer coupling tooth to the first gear ring in a second position, and controlling the gear sleeve to switch between the first position and the second position by a gear shifting device.

3. The dual planetary gear electric drive system as described in claim 1, characterized in that, The connecting device includes a first clutch and a second clutch, wherein the two ends of the first clutch that are engaged or disengaged are respectively disposed on the gearbox housing and the first planetary carrier; the two ends of the second clutch that are engaged or disengaged are respectively disposed on the first planetary carrier and the first ring gear; the engagement of the first clutch and the disengagement of the second clutch or the disengagement of the first clutch and the engagement of the second clutch are controlled by the gear shifting device.

4. The dual planetary gear electric drive system as described in any one of claims 1-3, characterized in that, Inside the gearbox housing, a first motor, a second motor, a first planetary gear set, and a second planetary gear set are arranged sequentially from front to back. The output shaft of the first motor freely passes through the hollow output shaft of the second motor and connects to the sun gear of the second planetary gear set. The hollow output shaft of the second motor is also connected to the sun gear of the first planetary gear set. Alternatively, inside the gearbox housing, a second motor, a first planetary gear set, a second planetary gear set, and a first motor are arranged sequentially from front to back. The output shaft of the system passes through the hollow output shaft of the first motor and outputs power to the drive axle located outside and behind the gearbox housing.

5. A shifting method for a dual planetary gearbox electric drive system, characterized in that, This invention relates to a dual planetary gear electric drive system, comprising a gearbox housing, a first motor, a second motor, a first planetary gear set, a second planetary gear set, a connecting device, and a system output shaft. The first planetary gear set includes a first sun gear, a first ring gear, and a first planetary carrier; the second planetary gear set includes a second sun gear, a second ring gear, and a second planetary carrier. The rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear. The first planetary carrier is connected to the second ring gear, and the second planetary carrier is connected to both the first ring gear and the system output shaft. The connecting device is used to fix the first planetary carrier to the gearbox housing to achieve first gear, or to fix the first planetary carrier to the first ring gear to lock the two planetary gear sets into a single unit with a speed ratio of 1 for second gear. The invention includes the following steps: 1) Control the working state of the first motor and the second motor so that the first motor drives the system output shaft alone and meets the torque required by the driver, and adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value. 2) When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation; 3) After disengaging the gear, keep the torque of the first motor constant and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value. 4) When the speed difference between the first planetary carrier and the first ring gear is less than the second calibration value, the first planetary carrier and the first ring gear are connected together through the connecting device, thereby completing the gear shift.

6. The gear shifting method as described in claim 5, characterized in that, In step 1), the first motor independently drives the system output shaft and provides the output torque required by the driver. for: ； In the formula, For the torque required by the driver, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. It is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear.

7. The gear shifting method as described in claim 5, characterized in that, In step 1), the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value of the output torque of the second motor. for: ； In the formula, For the torque required by the driver, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. It is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear.

8. The gear shifting method according to any one of claims 5-7, characterized in that, In step 3), in order to ensure that the difference between the rotational speed of the first planetary carrier and the rotational speed of the first planetary gear ring is less than the second calibration value, the second motor needs to output a second target torque. for: ; In the formula, The torque of the first motor, This is the ratio of the number of teeth on the first gear ring to the number of teeth on the first sun gear. This is the ratio of the number of teeth on the second gear ring to the number of teeth on the second sun gear. This indicates that based on the speed difference between the first planetary carrier and the first ring gear... The corrected torque for the second target torque obtained through calculation.

9. An electric-driven vehicle, characterized in that, The system includes a dual planetary gearbox electric drive system. This system comprises a gearbox housing, a first motor, a second motor, a first planetary gearbox, a second planetary gearbox, a connecting device, and a system output shaft. The first planetary gearbox includes a first sun gear, a first ring gear, and a first planet carrier. The second planetary gearbox includes a second sun gear, a second ring gear, and a second planet carrier. The rotor of the first motor is connected to the second sun gear, and the rotor of the second motor is connected to the first sun gear. The first planet carrier is connected to the second ring gear, and the second planet carrier is connected to both the first ring gear and the system output shaft. The connecting device is used to fix the first planet carrier to the gearbox housing to achieve first gear, or to fix the first planet carrier to the first ring gear to lock the two planetary gearboxes into a single unit with a speed ratio of 1 for second gear. The dual planetary gearbox electric drive system achieves first-gear shifting to second gear through the following steps: 1) Control the working state of the first motor and the second motor, so that the first motor drives the system output shaft alone and meets the torque required by the driver, and adjust the torque of the second motor in real time so that the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value. 2) When the difference between the torque of the first motor acting on the system output shaft and the torque of the second motor acting on the system output shaft is less than the first calibration value, the gearbox housing and the first planetary carrier are separated by the connecting device to complete the disengagement operation; 3) After disengaging the gear, keep the torque of the first motor constant and adjust the torque of the second motor so that the difference between the speed of the first planetary carrier and the speed of the first planetary gear ring is less than the second calibration value. 4) When the speed difference between the first planetary carrier and the first ring gear is less than the second calibration value, the first planetary carrier and the first ring gear are connected together through the connecting device, thereby completing the gear shift.

10. The electric drive vehicle as claimed in claim 9, characterized in that, The connecting device includes a coupling tooth fixed on the gearbox housing and an outer coupling tooth connected to the first planetary carrier, as well as a gear sleeve for fixing the coupling tooth to the outer coupling tooth in a first position or fixing the outer coupling tooth to the first gear ring in a second position, and controlling the gear sleeve to switch between the first position and the second position by a gear shifting device.

11. The electric drive vehicle as claimed in claim 9, characterized in that, The connecting device includes a first clutch and a second clutch, wherein the two ends of the first clutch that are engaged or disengaged are respectively disposed on the gearbox housing and the first planetary carrier; the two ends of the second clutch that are engaged or disengaged are respectively disposed on the first planetary carrier and the first ring gear; the engagement of the first clutch and the disengagement of the second clutch or the disengagement of the first clutch and the engagement of the second clutch are controlled by the gear shifting device.

12. The electric drive vehicle as described in any one of claims 9-11, characterized in that, Inside the gearbox housing, a first motor, a second motor, a first planetary gear set, and a second planetary gear set are arranged sequentially from front to back. The output shaft of the first motor freely passes through the hollow output shaft of the second motor and connects to the sun gear of the second planetary gear set. The hollow output shaft of the second motor is also connected to the sun gear of the first planetary gear set. Alternatively, inside the gearbox housing, a second motor, a first planetary gear set, a second planetary gear set, and a first motor are arranged sequentially from front to back. The output shaft of the system passes through the hollow output shaft of the first motor and outputs power to the drive axle located outside and behind the gearbox housing.

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