Planetary gearboxes, powertrains and electric vehicles

Abstract

This application provides a planetary reducer, a powertrain, and an electric vehicle, relating to the field of electric vehicle technology. The planetary reducer is used to drive the wheels of an electric vehicle. The planetary reducer includes multiple planetary gear sets, each including a sun gear, a ring gear, a planet carrier, and planet gears. The planet gears mesh with the sun gear and the ring gear respectively, and the planet carrier drives the planet gears. A first planetary gear set receives power and drives a second planetary gear set. The first and second planetary gear sets form two transmission paths, each driving one wheel. Due to the imbalance of torque losses caused by gears and bearings in the two transmission paths, the output torques of the two transmission paths are unequal. To reduce the difference in output torque between the two transmission paths, this application adjusts the transmission ratio of the second planetary gear set to be greater than that of the first planetary gear set, which is beneficial for improving the driving performance and safety performance of the electric vehicle.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to a planetary reducer, powertrain, and electric vehicle. Background Technology

[0002] In the powertrain of electric vehicles, planetary reducers are used to receive power from the drive motor and transmit output torque to different wheels. As the electric vehicle industry continues to develop, the requirements for vehicle safety performance are also increasing. If the output torque difference transmitted by the planetary reducer to different wheels is too large, it can easily lead to automatic steering wheel deflection, vehicle swerving, and uneven wear on different wheels, which is detrimental to improving the driving performance of electric vehicles and makes it difficult to meet driving safety requirements. Summary of the Invention

[0003] This application provides a planetary reducer, powertrain, and electric vehicle that can balance output torque and improve safety performance.

[0004] In a first aspect, embodiments of this application provide a planetary reducer for driving the wheels of an electric vehicle. The planetary reducer includes multiple planetary gear sets, each including a sun gear, a ring gear, a planet carrier, and planet gears. The planet gears mesh with the sun gear and the ring gear respectively, and the planet carrier drives the planet gears.

[0005] The system comprises multiple planetary gear sets, including a first planetary gear set and a second planetary gear set. The first planetary gear set receives power and is used to drive one wheel and the second planetary gear set, respectively. The second planetary gear set is used to drive another wheel.

[0006] The transmission ratio of the second planetary gear set is greater than that of the first planetary gear set.

[0007] In this embodiment, the first and second planetary gear sets of the planetary reducer form two transmission paths, each driving one wheel. Specifically, one transmission path includes the first planetary gear set and drives one wheel. The other transmission path includes the first and second planetary gear sets and drives another wheel. By using different transmission paths to drive two wheels and utilizing multiple planetary gear sets to achieve power distribution, the planetary reducer eliminates the need for a differential in the powertrain, facilitating the integration of deceleration and differential functions and reducing the size of the planetary reducer and powertrain.

[0008] However, the two transmission paths suffer from an imbalance in output torque. Since different transmission paths contain unequal numbers of planetary sets, theoretically, their torque losses will also differ. Specifically, torque losses in a transmission path typically originate from gears and bearings; unequal numbers of planetary sets indicate that the torque transmission passes through unequal numbers of gears and bearings. If the output torque difference between the two transmission paths is too large, it can easily lead to torque steer and uneven wear on different wheels, negatively impacting vehicle safety. Torque steer refers to the phenomenon of the steering wheel automatically turning and the wheels veering to one side during vehicle operation.

[0009] Adjusting the output torque by changing the number or layout of gears and bearings in different planetary gear sets may increase the design and manufacturing complexity of the planetary reducer and may also require corresponding adjustments to other components in the powertrain. Therefore, how to reduce the difference in torque output from a planetary reducer to different wheels while minimizing changes to the overall structure of the planetary reducer has become an urgent problem to be solved.

[0010] In a planetary reducer, the output torque of different transmission paths is affected not only by the gears and bearings in the planetary gear set but also by the gear ratio of the planetary gear set. The gear ratio is the ratio of input speed to output speed. The gear ratio of a planetary gear set can characterize its speed reduction and torque increase effect; increasing the gear ratio helps improve the output torque of the planetary gear set. In this application, the gear ratio of the planetary gear set is adjusted according to the magnitude of torque loss in different transmission paths, which helps to reduce the difference in output torque between different transmission paths. Specifically, the gear ratio of the second planetary gear set is greater than that of the first planetary gear set, making the gear ratio of another transmission path greater than that of one transmission path. This compensates for at least part of the torque loss caused by gears and bearings, helping to balance the torque output to different wheels by the planetary reducer with minimal structural modifications. The optimized power distribution of the planetary reducer improves the safety performance of the powertrain and electric vehicles, reducing the possibility of torque steer and uneven wear on different wheels.

[0011] In one embodiment, the ring gear of the first planetary gear set is used to receive power, the planet carrier of the first planetary gear set is used to drive a wheel, and the sun gear of the first planetary gear set is used to drive a sun gear of a second planetary gear set. The ring gear of the second planetary gear set is used to drive another wheel.

[0012] Among them, the number of teeth on the gear ring of the second planetary set is greater than the number of teeth on the gear ring of the first planetary set, and the number of teeth on the sun gear of the second planetary set is less than the number of teeth on the sun gear of the first planetary set.

[0013] In this embodiment, the transmission ratio of the planetary gear set is related to the number of teeth on the ring gear and the number of teeth on the sun gear. By adjusting the number of teeth on the ring gear and the number of teeth on the sun gear of different planetary gear sets, it is helpful to achieve a transmission ratio of the second planetary gear set greater than that of the first planetary gear set. The transmission ratio of the first planetary gear set is positively correlated with the ratio of the number of teeth on the sun gear to the number of teeth on the ring gear, and the transmission ratio of the second planetary gear set is positively correlated with the ratio of the number of teeth on the ring gear to the number of teeth on the sun gear. When the number of teeth on the ring gear of the second planetary gear set is greater than that on the ring gear of the first planetary gear set, and the number of teeth on the sun gear of the second planetary gear set is less than that on the sun gear of the first planetary gear set, the difference between the ratio of the number of teeth on the ring gear of the second planetary gear set and the number of teeth on the sun gear of the second planetary gear set and the ratio of the number of teeth on the sun gear to the number of teeth on the ring gear of the first planetary gear set can be widened. By adjusting the tooth ratio of the ring gear and the sun gear of different planetary sets, the output torque of another transmission path can be increased, which helps to balance the driving force of different wheels and improve the vehicle's driving performance.

[0014] In one embodiment, the difference between the number of teeth on the ring gear of the second planetary set and the number of teeth on the ring gear of the first planetary set is greater than the difference between the number of teeth on the sun gear of the first planetary set and the number of teeth on the sun gear of the second planetary set.

[0015] In this embodiment, by adjusting the relationship between the difference in the number of teeth on the ring gear of different planetary gear sets and the difference in the number of teeth on the sun gear of different planetary gear sets, it is beneficial to widen the difference in transmission ratio between the second planetary gear set and the first planetary gear set. Increasing the output torque of the other transmission path from the perspective of transmission ratio compensates for the torque loss of the other transmission path, which helps to balance the driving force provided by the planetary reducer to different wheels and improves the vehicle's safety performance.

[0016] In one embodiment, the difference between the number of teeth on the ring gear of the second planetary set and the number of teeth on the sun gear of the second planetary set is greater than the difference between the number of teeth on the ring gear of the first planetary set and the number of teeth on the sun gear of the first planetary set.

[0017] In this embodiment, by adjusting the relationship between the difference in the number of teeth between the ring gear and the sun gear of the first planetary gear set and the difference in the number of teeth between the ring gear and the sun gear of the second planetary gear set, it is beneficial to widen the difference in the transmission ratio between the second planetary gear set and the first planetary gear set. Since the magnitude of the transmission ratio affects the output torque, adjusting the number of teeth of the gears to make the transmission ratio of the second planetary gear set greater than that of the first planetary gear set helps to compensate for the torque loss in the other transmission path from the perspective of transmission ratio, balance the driving force received by different wheels, and reduce the possibility of torque steer and uneven wear of different wheels.

[0018] In one embodiment, the number of teeth on the planetary gears of the second planetary gear set is greater than the number of teeth on the planetary gears of the first planetary gear set.

[0019] In this embodiment, to satisfy the gear ratio relationship between the first and second planetary gear sets, it is necessary to adjust the number of teeth on the sun gear, ring gear, and other components of the first and second planetary gear sets. Since the planet gears of the first planetary gear set mesh with the sun gear and ring gear respectively, and the planet gears of the second planetary gear set mesh with the sun gear and ring gear respectively, this embodiment adjusts the number of teeth on the planet gears of the second planetary gear set to be greater than the number of teeth on the planet gears of the first planetary gear set. This helps ensure that the first and second planetary gear sets can transmit power normally.

[0020] In this embodiment, to reduce the difference in output torque between the two transmission paths, in addition to adjusting the transmission ratio, the torque loss of the other transmission path can also be reduced. The planetary gears of the second planetary gear set have a relatively large number of teeth, which is beneficial to increasing the meshing overlap. The meshing overlap refers to the number of simultaneously meshing tooth pairs. Increasing the meshing overlap helps to reduce single-tooth load fluctuations and reduce friction losses. In this embodiment, without reducing changes to the overall structure and layout of the planetary reducer, by increasing the difference in the number of teeth between the planetary gears of the second planetary gear set and the planetary gears of the first planetary gear set, not only are the requirements for normal meshing of the planetary gears with the sun gear and ring gear met, but the output torque of the two transmission paths can also be balanced, thereby improving the vehicle's driving performance.

[0021] In one embodiment, the sun gear of the first planetary gear set has 54 teeth, and the ring gear of the first planetary gear set has 110 teeth. The sun gear of the second planetary gear set has 52 teeth, and the ring gear of the second planetary gear set has 158 teeth.

[0022] Based on the strategy for adjusting the number of gear teeth provided in the embodiments of this application, the number of teeth of the sun gear of the first planetary gear set, the ring gear of the first planetary gear set, the sun gear of the second planetary gear set, and the ring gear of the second planetary gear set can be adjusted to the specific values ​​mentioned above, so that the transmission ratio of the second planetary gear set is greater than that of the first planetary gear set, thereby reducing the difference in output torque between the two transmission paths.

[0023] In one embodiment, the center distance between the ring gear of the second planetary set and the sun gear of the second planetary set is smaller than the center distance between the ring gear of the first planetary set and the sun gear of the first planetary set.

[0024] In this embodiment, by adjusting the relationship between the center distance of the gears of the second planetary gear set and the center distance of the gears of the first planetary gear set, it is beneficial to increase the meshing overlap of the second planetary gear set and reduce the torque loss of the other transmission path.

[0025] In one embodiment, the sun gear of the first planetary gear set is used to receive power, and the planet carrier of the first planetary gear set is used to drive a wheel. The ring gear of the first planetary gear set is used to drive the sun gear of the second planetary gear set, and the ring gear of the second planetary gear set is used to drive another wheel.

[0026] The number of teeth on the gear ring of the second planetary set is greater than the number of teeth on the gear ring of the first planetary set.

[0027] In this embodiment, the transmission ratio of the second planetary gear set is positively correlated with the number of teeth on the ring gear of the second planetary gear set. When the number of teeth on the ring gear of the second planetary gear set is greater than the number of teeth on the ring gear of the first planetary gear set, it helps to widen the gap between the transmission ratios of the second and first planetary gear sets. By adjusting the relationship between the number of teeth on the sun gears of different planetary gear sets, the output torque of the other transmission path is increased, which helps to balance the driving force of different wheels and improve the vehicle's driving performance.

[0028] In one embodiment, the ratio of the number of teeth on the ring gear of the second planetary set to the number of teeth on the sun gear of the second planetary set is greater than the ratio of the number of teeth on the ring gear of the first planetary set to the number of teeth on the sun gear of the first planetary set.

[0029] In this embodiment, by adjusting the gear ratio between the ring gear and the sun gear of different planetary gear sets, it is beneficial to widen the difference in transmission ratio between the second planetary gear set and the first planetary gear set. Increasing the output torque of the other transmission path from the perspective of transmission ratio compensates for the torque loss in that path, which helps to balance the driving force provided by the planetary reducer to different wheels and improves vehicle safety performance.

[0030] In one embodiment, the plurality of planetary gear sets further includes a third planetary gear set for transmitting power output from the drive motor of the electric vehicle to the first planetary gear set. The difference between the gear ratio of the first planetary gear set and the gear ratio of the second planetary gear set is less than the difference between the gear ratio of either the first or second planetary gear set and the gear ratio of the third planetary gear set.

[0031] In this embodiment, the third planetary gear set is connected between the drive motor and the first planetary gear set, and the first planetary gear set is used to receive the power after being reduced in speed by the third planetary gear set. When the planetary reducer includes the third planetary gear set, one transmission path includes the third planetary gear set and the first planetary gear set, and another transmission path includes the third planetary gear set, the first planetary gear set, and the second planetary gear set.

[0032] This embodiment of the application reduces the difference in output torque between different transmission paths in the planetary reducer by adjusting the transmission ratio of the second planetary gear set to be greater than that of the first planetary gear set. However, the difference between the transmission ratios of the second and first planetary gear sets cannot be too large, otherwise it may lead to excessive output torque in the other transmission path, making it difficult to achieve the effect of balancing the output torque of different transmission paths.

[0033] In this embodiment, the third planetary gear set is used to achieve the first stage of speed reduction, and the transmission ratio of the third planetary gear set is generally set to a relatively large value. In a planetary reducer that includes a third planetary gear set, by comparing the transmission ratio of the third planetary gear set with the transmission ratios of the first and second planetary gear sets, the difference between the transmission ratios of the first and second planetary gear sets is controlled, thus avoiding uneven power distribution in the planetary reducer.

[0034] In one embodiment, the ratio of the number of teeth on the ring gear of each of the first and second planetary gear sets to the number of teeth on the sun gear is less than the ratio of the number of teeth on the ring gear of the third planetary gear set to the number of teeth on the sun gear.

[0035] In this embodiment, by adjusting the ratio of the number of teeth on the ring gear to the number of teeth on the sun gear in different planetary gear sets, the transmission ratio difference between the second planetary gear set and the first planetary gear set can be controlled within a reasonable range. This embodiment can compensate for the torque loss of different transmission paths from the perspective of transmission ratio, and can also control the increase in output torque of another transmission path, which helps to balance the torque output to the two wheels by different transmission paths, thereby improving the vehicle's driving performance and safety performance.

[0036] In one embodiment, the housing of the planetary reducer is used to accommodate a first planetary gear set and a second planetary gear set. The planet carrier or ring gear of the second planetary gear set is used to securely connect to the housing of the planetary reducer, and the first planetary gear set is spaced apart from the housing of the planetary reducer.

[0037] In this embodiment, when the planetary reducer is in operation, the sun gear, ring gear, planet carrier, and planet gears of the first planetary gear set need to rotate relative to the reducer housing. The distance between the first planetary gear set and the reducer housing helps prevent interference. The connection between the planet carrier or ring gear of the second planetary gear set and the reducer housing improves rigidity and reduces resonance. Since the first planetary gear set is not constrained by the reducer housing, its degrees of freedom are greater than those of the second planetary gear set, allowing the reducer to utilize the first planetary gear set for differential speed control, reducing the number and size of structural components. It is understood that when the ring gear of the second planetary gear set is used to drive the wheels, it is spaced apart from the reducer housing.

[0038] In one embodiment, the difference between the gear ratio of the second planetary gear set and the gear ratio of the first planetary gear set is greater than or equal to 0.005% of the gear ratio of the first planetary gear set.

[0039] In this embodiment, by adjusting the lower limit of the difference between the transmission ratios of the second planetary gear set and the first planetary gear set, it is helpful to use the larger transmission ratio of the second planetary gear set to compensate for the torque loss of the other transmission path and reduce the difference in output torque between the two transmission paths.

[0040] Secondly, embodiments of this application provide a powertrain, which includes a drive motor and a planetary reducer as described in any embodiment of the first aspect, wherein the drive motor is used to drive the planetary reducer.

[0041] In the embodiments of this application, the planetary reducer from any embodiment of the first aspect is applied to the powertrain. Since the torque distribution among different planetary sets in the planetary reducer is optimized, it helps improve the reliability of the powertrain and extend its service life. The overall structure and layout of the planetary reducer require minimal modification, which helps reduce the design and layout complexity of the powertrain.

[0042] Thirdly, embodiments of this application provide an electric vehicle, which includes a power battery and the powertrain mentioned in the second aspect. The powertrain is used to receive power from the power battery and to drive the wheels of the electric vehicle.

[0043] In this embodiment of the application, the powertrain in the second aspect is applied to an electric vehicle. The powertrain provides a more balanced driving force to different wheels, which can reduce the risk of torque steer and uneven wear of different wheels, optimize the driving performance of the electric vehicle, and ensure driving safety.

[0044] In one embodiment, the electric vehicle includes a power battery and a planetary gearbox as described in any embodiment of the first aspect, the planetary gearbox being used to drive the wheels of the electric vehicle.

[0045] In the embodiments of this application, applying the planetary reducer of any embodiment of the first aspect to an electric vehicle helps to avoid problems such as wheel misalignment or severe wear of some wheels, thereby improving the driving performance and safety performance of the electric vehicle. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0047] Figure 1 This is a schematic diagram of an electric vehicle provided in an embodiment of this application; Figure 2 This is a schematic diagram of the powertrain and wheels provided in an embodiment of this application; Figure 3 This is a schematic diagram of the powertrain provided in an embodiment of this application; Figure 4This is a schematic diagram of the planetary reducer and adapter shaft provided in the embodiments of this application; Figure 5 This is a schematic diagram of the planetary reducer and adapter shaft provided in the embodiments of this application; Figure 6 This is a schematic diagram of the planetary reducer and adapter shaft provided in the embodiments of this application; Figure 7 This is a schematic diagram of the planetary reducer and adapter shaft provided in the embodiments of this application; Figure 8 This is a schematic diagram of the planetary reducer and adapter shaft provided in the embodiments of this application. Detailed Implementation

[0048] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0049] Currently, planetary reducers face the problem of unbalanced output torque across different planetary gear sets. To reduce the difference in output torque between different planetary gear sets, this application provides a planetary reducer used to drive the wheels of an electric vehicle. The planetary reducer includes multiple planetary gear sets, each including a sun gear, a ring gear, a planet carrier, and planet gears. The planet gears mesh with the sun gear and the ring gear respectively, and the planet carrier drives the planet gears. The multiple planetary gear sets include a first planetary gear set and a second planetary gear set. The first planetary gear set receives power and drives the second planetary gear set, while the second planetary gear set receives power transmitted from the first planetary gear set. The first and second planetary gear sets form two transmission paths, each driving one wheel. Due to unbalanced losses caused by gears and bearings, the output torques of the two transmission paths are unequal. To improve the driving performance of the electric vehicle, this application adjusts the gear ratio of the second planetary gear set to be greater than that of the first planetary gear set to reduce the difference in output torque between the two transmission paths. The risks of torque steer and uneven wear between the left and right wheels of the electric vehicle are reduced, which is beneficial to improving driving safety.

[0050] The planetary reducer provided in this application embodiment can be applied to powertrains and electric vehicles.

[0051] Please see Figure 1 , Figure 1 This is a schematic diagram of the electric vehicle 1 provided in an embodiment of this application.

[0052] The electric vehicle 1 in this embodiment includes a powertrain 10 and a power battery 20. In this embodiment, the electric vehicle 1 refers to a wheeled device driven or towed by a power unit. The power battery 20 supplies power to the powertrain 10; the power battery 20 can also be called a battery pack. The powertrain 10 is the power source for the electric vehicle 1 and drives the wheels 30 of the electric vehicle 1. In one embodiment, the electric vehicle 1 further includes a frame 40, which is used to mount the powertrain 10 and the power battery 20. The frame 40 is the structural skeleton of the electric vehicle 1 and can withstand the loads from the internal and external environments of the electric vehicle 1.

[0053] It should be noted that, Figure 1 The electric vehicle 1 is shown schematically only, including the powertrain 10, power battery 20, wheels 30 and frame 40, and does not represent the specific structure, size and positional relationship of the powertrain 10, power battery 20, wheels 30 and frame 40.

[0054] Please see Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the powertrain 10 and wheels 30 provided in an embodiment of this application. Figure 3 This is a schematic diagram of the powertrain 10 provided in the embodiments of this application.

[0055] The powertrain 10 of this application embodiment includes a drive motor 200 and a planetary reducer 100. In one embodiment, the powertrain 10 also includes a motor controller 300. It should be noted that the figures do not represent the actual structure, size, and positional relationship of the motor controller 300, drive motor 200, planetary reducer 100, and wheels.

[0056] The power battery supplies power to the drive motor 200 via the motor controller 300. The motor controller 300 converts the direct current supplied by the power battery into alternating current and delivers the alternating current to the drive motor 200. In one embodiment, the motor controller 300 is also used to control at least one of the drive motor 200 or a reducer.

[0057] The drive motor 200 converts electrical energy into mechanical energy to generate driving torque. In one embodiment, the drive motor 200 includes a motor shaft, a motor rotor, and a motor stator. The motor shaft is used to fixably connect to the inner circumferential surface of the motor rotor. The windings of the motor stator are used to receive alternating current transmitted by the motor controller 300. After receiving the alternating current provided by the motor controller 300, the motor stator drives the motor rotor to rotate, thereby driving the motor shaft to rotate.

[0058] The planetary reducer 100 is used to reduce the speed of the power output by the drive motor 200 and increase the output torque. Depending on the different architectures used, reducers can be divided into planetary reducers 100 and parallel shaft reducers. The planetary reducer 100 adopts an architecture where the input and output ends are arranged coaxially. Compared with parallel shaft reducers, the planetary reducer 100 has the advantages of a compact structural layout and smaller radial dimensions. The planetary reducer 100 of this embodiment includes at least two planetary gear sets 110. Each planetary gear set 110 includes a sun gear 111, a ring gear 112, a planet carrier 113, and planet gears 114. The planet gears 114 are used to mesh with at least one of the sun gear 111 and the ring gear 112. The planet carrier 113 is connected to the planet gears 114 via planet shafts. One of the sun gear 111, planet carrier 113, and ring gear 112 is the input end, and at least one of the sun gear 111, planet carrier 113, and ring gear 112 is the output end. It should be noted that... Figure 3 This does not represent the actual structure, size, and positional relationship of the sun gear 111, planet gear 114, planet carrier 113, and gear ring 112 in planetary gear set 110.

[0059] In one embodiment, the powertrain 10 includes a differential, or the planetary reducer 100 of the powertrain 10 has a differential function. When the electric vehicle is turning or traveling on uneven surfaces, the differential or the planetary reducer 100 with a differential function enables the wheels on different sides to rotate at different speeds.

[0060] In one embodiment, the powertrain 10 includes a transition shaft 400, and a drive motor 200 drives the transition shaft 400 via a planetary reducer 100. The transition shaft 400 is used to drive a wheel. In one embodiment, the transition shaft 400a is used to drive one wheel via a drive shaft 500a, and the transition shaft 400b is used to drive another wheel via a drive shaft 500b. It should be noted that... Figure 2 This does not represent the actual structure, dimensions, or positional relationship between the adapter shaft 400 and the drive shaft 500.

[0061] If the output torque provided by the planetary reducer 100 to different wheels differs too much, it can easily lead to torque steer and uneven wear on different wheels. This application embodiment improves the planetary reducer 100 and optimizes its power distribution, which is beneficial for improving the overall vehicle driving performance and safety.

[0062] The planetary reducer 100 provided in the embodiments of this application is described in detail below.

[0063] Please refer to the following: Figure 3 and Figure 4 , Figure 4 This is a schematic diagram of the planetary reducer 100 and the adapter shaft 400 provided in the embodiments of this application.

[0064] The planetary reducer 100 of this application embodiment includes a plurality of planetary gear sets 110. In each planetary gear set 110, planetary gears 114 are used to mesh with a sun gear 111 and a ring gear 112, respectively, and a planet carrier 113 is used to drive the planetary gears 114. The plurality of planetary gear sets 110 includes a first planetary gear set 110a and a second planetary gear set 110b. The first planetary gear set 110a is used to receive power and is used to drive the first wheel and the second planetary gear set 110b, respectively. The second planetary gear set 110b is used to drive the other wheel. The transmission ratio of the second planetary gear set 110b is greater than the transmission ratio of the first planetary gear set 110a. In one embodiment, the first planetary gear set 110a is used to drive the first wheel via a transition shaft 400a, and the second planetary gear set 110b is used to drive the other wheel via a transition shaft 400b.

[0065] In this embodiment, the first planetary gear set 110a and the second planetary gear set 110b of the planetary reducer 100 form two transmission paths, each driving one wheel. Specifically, one transmission path includes the first planetary gear set 110a and drives one wheel. The other transmission path includes the first planetary gear set 110a and the second planetary gear set 110b and drives another wheel. By using different transmission paths to drive two wheels and utilizing multiple planetary gear sets 110 to achieve power distribution, the planetary reducer 10 eliminates the need for a differential, facilitating the integration of deceleration and differential functions, and reducing the size of both the planetary reducer 100 and the powertrain 10.

[0066] However, the two transmission paths suffer from an imbalance in output torque. Since the number of planetary gear sets (110) in different transmission paths is unequal, theoretically, the torque loss in each path will also differ. Specifically, torque loss in the transmission path typically originates from gears and bearings; the unequal number of planetary gear sets (110) indicates that the number of gears and bearings through which torque is transmitted is also unequal. If the difference in output torque between the two transmission paths and the difference in rotational speed between the two adapter shafts (400) are too large, it can easily lead to torque steer and uneven wear on different wheels, which is detrimental to improving vehicle safety performance. Torque steer refers to the phenomenon of the steering wheel automatically turning and the wheels veering to one side during vehicle operation.

[0067] Adjusting the output torque by changing the number or layout of gears and bearings in different planetary gear sets 110 may increase the design and manufacturing difficulty of the planetary reducer 100, and may also require corresponding adjustments to other components in the powertrain 10. Therefore, how to reduce the difference in torque output by the planetary reducer 100 to different wheels while minimizing changes to the overall structure of the planetary reducer 100 has become an urgent problem to be solved.

[0068] The output torque of different transmission paths in the planetary reducer 100 is affected not only by the gears and bearings in the planetary gear set 110, but also by the gear ratio of the planetary gear set 110. The gear ratio is the ratio of input speed to output speed. The gear ratio of the planetary gear set 110 can be used to characterize its speed reduction and torque increase effect; increasing the gear ratio of the planetary gear set 110 is beneficial to increasing its output torque. In this embodiment, the gear ratio of the planetary gear set 110 is adjusted according to the magnitude of torque loss in different transmission paths, which helps to reduce the difference in output torque between different transmission paths. Specifically, the gear ratio of the second planetary gear set 110b is greater than that of the first planetary gear set 110a, making the gear ratio of another transmission path greater than that of one transmission path. This compensates for at least part of the torque loss caused by gears and bearings, helping to balance the torque output by the planetary reducer 100 to different wheels with less structural modification. The optimized power distribution of the planetary reducer 100 is beneficial to improving the safety performance of the powertrain 10 and the electric vehicle, and reducing the possibility of torque steer and uneven wear on different wheels.

[0069] In one embodiment, the difference between the gear ratio of the second planetary gear set 110b and the gear ratio of the first planetary gear set 110a is greater than or equal to 0.005% relative to the gear ratio of the first planetary gear set 110a.

[0070] In this embodiment, by adjusting the lower limit of the difference between the transmission ratios of the second planetary gear set 110b and the first planetary gear set 110a, it is helpful to use the larger transmission ratio of the second planetary gear set 110b to compensate for the torque loss in the other transmission path, thereby reducing the difference in output torque between the two transmission paths. In one embodiment, the ratio of the difference between the transmission ratio of the second planetary gear set 110b and the transmission ratio of the first planetary gear set 110a to the transmission ratio of the first planetary gear set 110a is greater than or equal to 0.05%.

[0071] Please refer to the following: Figures 4 to 8 , Figures 4 to 8 These are schematic diagrams of the planetary reducer 100 and the adapter shaft 400 provided in the embodiments of this application. For ease of description, the sun gear 111, ring gear 112, planet carrier 113, and planet gear 114 of the first planetary gear set 110a are respectively referred to as the first sun gear 111a, the first ring gear 112a, the first planet carrier 113a, and the first planet gear 114a. The sun gear 111, ring gear 112, planet carrier 113, and planet gear 114 of the second planetary gear set 110b are respectively referred to as the second sun gear 111b, the second ring gear 112b, the second planet carrier 113b, and the second planet gear 114b.

[0072] Based on the transmission method of planetary gear 110, it can be known that in Figure 4In the planetary reducer 100 shown, the first planetary gear set 110a receives power through the first ring gear 112a, and the first planetary gear set 110a is connected to the adapter shaft 400a and the second sun gear 111b via the first planet carrier 113a and the first sun gear 111a, respectively. Figures 5 to 8 In the planetary reducer 100 shown, the first planetary gear set 110a receives power through the first sun gear 111a, and the first planetary gear set 110a is connected to the adapter shaft 400a and the second sun gear 111b through the first planet carrier 113a and the first gear ring 112a respectively.

[0073] Based on the layout of planetary arrangement 110, it can be seen that in Figure 4 , Figure 6 and Figure 8 In the planetary reducer 100 shown, the first planetary gear set 110a and the second planetary gear set 110b are arranged along the axial direction O of the planetary reducer 100. Figure 5 and Figure 7 In the planetary reducer 100 shown, the first planetary gear set 110a and the second planetary gear set 110b are arranged along the radial direction R of the planetary reducer 100.

[0074] Based on the specific number of planetary alignment 110, it can be known that... Figure 4 , Figure 7 and Figure 8 In the planetary reducer 100 shown, the multiple planetary sets 110 of the planetary reducer 100 also include a third planetary set 110c, which is used to transmit the power output from the drive motor 200 to the first planetary set 110a. Figure 5 and Figure 6 In the planetary reducer 100 shown, the first planetary gear set 110a is used to directly receive the power output from the drive motor 200.

[0075] It is understood that the method of balancing the output torque of different transmission paths by adjusting the transmission ratios of different planetary gear sets 110 in this application embodiment is applicable to... Figures 4 to 8 The planetary reducer 100 shown has a different architecture. Figures 4 to 8 The dashed boxes in the diagram are only used to show the arrangement of the multiple planetary rows 110 and do not represent the actual volume occupied by the multiple planetary rows 110 in the planetary reducer 100.

[0076] The following is based on Figure 3 and Figure 4 Taking the planetary reducer 100 shown as an example, this application describes the strategy for adjusting the transmission ratio in its embodiments.

[0077] Please continue reading. Figure 4In one embodiment, a first ring gear 112a receives power, a first planetary carrier 113a is used to drive a wheel, and a first sun gear 111a is used to drive a second sun gear 111b. The second ring gear 112b is used to drive another wheel. The number of teeth on the second ring gear 112b is greater than the number of teeth on the first ring gear 112a, and the number of teeth on the second sun gear 111b is less than the number of teeth on the first sun gear 111a.

[0078] In this embodiment, the transmission ratio of the planetary gear set 110 is related to the number of teeth on the ring gear 112 and the number of teeth on the sun gear 111. By adjusting the number of teeth on the ring gear 112 and the sun gear 111 of different planetary gear sets 110, it is helpful to achieve a transmission ratio of the second planetary gear set 110b that is greater than that of the first planetary gear set 110a. The transmission ratio of the first planetary gear set 110a is positively correlated with the ratio of the number of teeth on the first sun gear 111a to the number of teeth on the first ring gear 112a, and the transmission ratio of the second planetary gear set 110b is positively correlated with the ratio of the number of teeth on the second ring gear 112b to the number of teeth on the second sun gear 111b. When the number of teeth on the second ring gear 112b is greater than the number of teeth on the first ring gear 112a, and the number of teeth on the second sun gear 111b is less than the number of teeth on the first sun gear 111a, the difference between the ratio of the number of teeth on the second ring gear 112b and the ratio of the number of teeth on the first sun gear 111a to the number of teeth on the first ring gear 112a can be increased. By adjusting the relationship between the number of teeth on the ring gear 112 of different planetary gear sets 110 and the number of teeth on the sun gear 111 of different planetary gear sets 110, the output torque of the other transmission path can be increased, which helps to balance the driving force of different wheels and improve the vehicle's driving performance.

[0079] Please continue reading. Figure 4 In one embodiment, the difference between the number of teeth of the second gear ring 112b and the number of teeth of the first gear ring 112a is greater than the difference between the number of teeth of the first sun gear 111a and the number of teeth of the second sun gear 111b.

[0080] In this embodiment, by adjusting the relationship between the difference in the number of teeth on the ring gear 112 of different planetary gear sets 110 and the difference in the number of teeth on the sun gear 111 of different planetary gear sets 110, it is beneficial to widen the difference in transmission ratio between the second planetary gear set 110b and the first planetary gear set 110a. Increasing the output torque of the other transmission path from the perspective of transmission ratio compensates for the torque loss of the other transmission path, which helps to balance the driving force provided by the planetary reducer 100 to different wheels and improves the vehicle's safety performance. It should be noted that the differences in this embodiment are all absolute values.

[0081] Please continue reading. Figure 4 In one embodiment, the difference between the number of teeth of the second gear ring 112b and the number of teeth of the second sun gear 111b is greater than the difference between the number of teeth of the first gear ring 112a and the number of teeth of the first sun gear 111a.

[0082] In this embodiment, by adjusting the relationship between the difference in the number of teeth between the ring gear 112 and the sun gear 111 of the first planetary gear set 110a and the difference in the number of teeth between the ring gear 112 and the sun gear 111 of the second planetary gear set 110b, it is beneficial to widen the difference in transmission ratio between the second planetary gear set 110b and the first planetary gear set 110a. Since the size of the transmission ratio affects the output torque, by adjusting the number of teeth of the gears to make the transmission ratio of the second planetary gear set 110b greater than that of the first planetary gear set 110a, it is beneficial to compensate for the torque loss of the other transmission path from the perspective of transmission ratio, balance the driving force received by different wheels, and reduce the possibility of torque steer and uneven wear of different wheels.

[0083] Please continue reading. Figure 4 In one embodiment, the first sun gear 111a has 54 teeth, and the first ring gear 112a has 110 teeth. The second sun gear 111b has 52 teeth, and the second ring gear 112b has 158 teeth.

[0084] Based on the strategy of adjusting the number of gear teeth provided in the embodiments of this application, the number of teeth of the first sun gear 111a, the first ring gear 112a, the second sun gear 111b, and the second ring gear 112b can be adjusted to the specific values ​​mentioned above, so that the transmission ratio of the second planetary gear set 110b is greater than the transmission ratio of the first planetary gear set 110a, thereby reducing the difference in output torque between the two transmission paths.

[0085] Please continue reading. Figure 4 In one embodiment, the second planetary gear 114b has a greater number of teeth than the first planetary gear 114a.

[0086] In this embodiment, to satisfy the transmission ratio relationship between the first planetary gear set 110a and the second planetary gear set 110b, it is necessary to adjust the number of teeth on the first sun gear 111a, the first ring gear 112a, the second sun gear 111b, and the second ring gear 112b. Since the first planetary gear 114a meshes with the first sun gear 111a and the first ring gear 112a respectively, and the second planetary gear 114b meshes with the second sun gear 111b and the second ring gear 112b respectively, this embodiment adjusts the number of teeth on the second planetary gear 114b to be greater than the number of teeth on the first planetary gear 114a, which helps to ensure that the first planetary gear set 110a and the second planetary gear set 110b can transmit power normally.

[0087] In this embodiment, to reduce the difference in output torque between the two transmission paths, in addition to adjusting the transmission ratio, the torque loss of the other transmission path can also be reduced. The second planetary gear 114b has a relatively large number of teeth, which is beneficial to increasing the meshing overlap. The meshing overlap refers to the number of teeth pairs meshing simultaneously. Increasing the meshing overlap helps to reduce single-tooth load fluctuation and reduce friction loss. In this embodiment, without reducing changes to the overall structure and layout of the planetary reducer 100, by increasing the difference in the number of teeth between the second planetary gear 114b and the first planetary gear 114a, not only are the requirements for normal meshing of the planetary gear 114 with the sun gear 111 and the ring gear 112 met, but the output torque of the two transmission paths can also be balanced, thereby improving the vehicle's driving performance.

[0088] Please continue reading. Figure 4 In one embodiment, the center distance between the second gear ring 112b and the second sun gear 111b is smaller than the center distance between the first gear ring 112a and the first sun gear 111a.

[0089] In this embodiment of the application, by adjusting the relationship between the center distance of the gears of the second planetary gear set 110b and the center distance of the gears of the first planetary gear set 110a, it is beneficial to increase the meshing overlap of the second planetary gear set 110b and reduce the torque loss of the other transmission path.

[0090] Please continue reading. Figures 5 to 8 In one embodiment, a first sun gear 111a receives power, and a first planetary carrier 113a drives a wheel. A first ring gear 112a drives the sun gear 111 of a second planetary carrier 110b, and a second ring gear 112b drives another wheel. The second ring gear 112b has a greater number of teeth than the first ring gear 112a.

[0091] In this embodiment, the transmission ratio of the second planetary gear set 110b is positively correlated with the number of teeth of the second ring gear 112b. When the number of teeth of the second ring gear 112b is greater than the number of teeth of the first ring gear 112a, it helps to widen the gap between the transmission ratio of the second planetary gear set 110b and the transmission ratio of the first planetary gear set 110a. By adjusting the relationship between the number of teeth of the sun gear 111 of different planetary gear sets 110, the output torque of the other transmission path is increased, which helps to balance the driving force of different wheels and improve the driving performance of the vehicle.

[0092] like Figure 5 and Figure 7 As shown, in one embodiment, the sun gear 111 of the second planetary gear 110b is distributed on the outer circumferential surface of the gear ring 112 of the first planetary gear 110a.

[0093] In one embodiment, the ratio of the number of teeth of the second gear ring 112b to the number of teeth of the second sun gear 111b is greater than the ratio of the number of teeth of the first gear ring 112a to the number of teeth of the first sun gear 111a.

[0094] In this embodiment, by adjusting the gear ratio between the ring gear 112 and the sun gear 111 of different planetary gear sets 110, it is beneficial to widen the difference in transmission ratio between the second planetary gear set 110b and the first planetary gear set 110a. Increasing the output torque of the other transmission path from the perspective of transmission ratio compensates for the torque loss of the other transmission path, which helps to balance the driving force provided by the planetary reducer 100 to different wheels and improves the vehicle's safety performance.

[0095] Please continue reading. Figure 4 , Figure 7 and Figure 8 In one embodiment, the plurality of planetary gear sets 110 further includes a third planetary gear set 110c, which is used to transmit the power output by the drive motor 200 to the first planetary gear set 110a. The difference between the transmission ratio of the first planetary gear set 110a and the transmission ratio of the second planetary gear set 110b is less than the difference between the transmission ratio of either the first planetary gear set 110a or the second planetary gear set 110b and the transmission ratio of the third planetary gear set 110c.

[0096] In this embodiment, the third planetary gear set 110c is driven between the drive motor 200 and the first planetary gear set 110a, and the first planetary gear set 110a is used to receive the power reduced by the third planetary gear set 110c. When the planetary reducer 100 includes the third planetary gear set 110c, one transmission path includes the third planetary gear set 110c and the first planetary gear set 110a, and another transmission path includes the third planetary gear set 110c, the first planetary gear set 110a, and the second planetary gear set 110b.

[0097] This embodiment of the application reduces the difference in output torque between different transmission paths in the planetary reducer 100 by adjusting the transmission ratio of the second planetary gear set 110b to be greater than that of the first planetary gear set 110a. However, the difference in transmission ratio between the second planetary gear set 110b and the first planetary gear set 110a cannot be too large, otherwise it may lead to excessive output torque in the other transmission path, making it difficult to achieve the effect of balancing the output torque of different transmission paths.

[0098] In this embodiment, the third planetary gear set 110c is used to achieve the first stage of speed reduction, and the transmission ratio of the third planetary gear set 110c is generally set to a relatively large value. In the planetary reducer 100 including the third planetary gear set 110c, by comparing the transmission ratio of the third planetary gear set 110c with the transmission ratios of the first planetary gear set 110a and the second planetary gear set 110b, the difference in transmission ratios between the first planetary gear set 110a and the second planetary gear set 110b is controlled, thus avoiding uneven power distribution in the planetary reducer 100.

[0099] In one embodiment, when the planetary reducer 100 includes a third planetary gear set 110c, the torque loss ratio caused by gears in one transmission path and another transmission path is 0.244:0.387, and the torque loss ratio caused by bearings in one transmission path and another transmission path is 0.646:1.015. In this embodiment, by adjusting the transmission ratio of the first planetary gear set 110a and the second planetary gear set 110b, the relative difference in output torque between the two transmission paths can be reduced to 0.5%.

[0100] For ease of description, the sun gear 111 and the gear ring 112 of the third planetary array 110c will be referred to as the third sun gear 111c and the third gear ring 112c, respectively.

[0101] Please continue reading. Figure 4 , Figure 7 and Figure 8 In one embodiment, the ratio of the number of teeth of the first gear ring 112a to the number of teeth of the first sun gear 111a is less than the ratio of the number of teeth of the third gear ring 112c to the number of teeth of the third sun gear 111c. Similarly, the ratio of the number of teeth of the second gear ring 112b to the number of teeth of the second sun gear 111b is less than the ratio of the number of teeth of the third gear ring 112c to the number of teeth of the third sun gear 111c.

[0102] In this embodiment, by adjusting the ratio of the number of teeth of the ring gear 112 to the number of teeth of the sun gear 111 between different planetary gear sets 110, the transmission ratio difference between the second planetary gear set 110b and the first planetary gear set 110a can be controlled within a reasonable range. This embodiment can compensate for the torque loss of different transmission paths from the perspective of transmission ratio, and can also control the increase in output torque of another transmission path, which helps to balance the torque output to the two wheels by different transmission paths, thereby improving the vehicle's driving performance and safety performance.

[0103] Please continue reading. Figures 4 to 8 In one embodiment, the housing 101 of the planetary reducer 100 is used to accommodate a first planetary gear set 110a and a second planetary gear set 110b. A second planetary carrier 113b or a second ring gear 112b is used to fixably connect to the housing 101 of the planetary reducer 100, and the first planetary gear set 110a is spaced apart from the housing 101 of the planetary reducer 100.

[0104] In this embodiment, when the planetary reducer 100 is in operation, the first sun gear 111a, the first ring gear 112a, the first planet carrier 113a, and the first planet gear 114a need to rotate relative to the housing 101 of the planetary reducer 100. The first planetary set 110a is spaced from the housing 101 of the planetary reducer 100, which helps to avoid interference between the first planetary set 110a and the reducer housing. The second planet carrier 113b or the second ring gear 112b is connected to the housing 101 of the planetary reducer 100, which helps to improve the rigidity of the second planet carrier 113b or the second ring gear 112b and reduce resonance. Since the first planetary set 110a is not constrained by the housing 101 of the planetary reducer 100, the degree of freedom of the first planetary set 110a is greater than that of the second planetary set 110b, allowing the planetary reducer 100 to utilize the first planetary set 110a to achieve differential speed function, reducing the number and size of the structural components of the planetary reducer 100. Understandably, when the second gear ring 112b is used to drive the wheels, the second gear ring 112b is spaced apart from the housing 101 of the planetary reducer 100. Figures 3 to 8 This is only used to illustrate the connection between part of the structure of the planetary gearbox 110 and the housing 101 of the planetary reducer 100, and does not represent the actual structure and size of the housing 101 of the planetary reducer 100.

[0105] The planetary reducer, powertrain, and electric vehicle provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and embodiments of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in specific embodiments and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A planetary reducer, characterized in that, The planetary reducer is used to drive the wheels of an electric vehicle. The planetary reducer includes multiple planetary gear sets. Each planetary gear set includes a sun gear, a ring gear, a planet carrier, and planet gears. The planet gears are used to mesh with the sun gear and the ring gear respectively. The planet carrier is used to drive the planet gears. The plurality of planetary gear sets include a first planetary gear set and a second planetary gear set. The first planetary gear set is used to receive power and is used to drive one of the wheels and the second planetary gear set respectively. The second planetary gear set is used to drive the other wheel, wherein: The transmission ratio of the second planetary gear set is greater than that of the first planetary gear set.

2. The planetary reducer according to claim 1, characterized in that, The ring gear of the first planetary gear set is used to receive power, the planet carrier of the first planetary gear set is used to drive the drive of one wheel, the sun gear of the first planetary gear set is used to drive the drive of the sun gear of the second planetary gear set, and the ring gear of the second planetary gear set is used to drive the drive of the other wheel, wherein: The number of teeth on the ring gear of the second planetary set is greater than the number of teeth on the ring gear of the first planetary set, and the number of teeth on the sun gear of the second planetary set is less than the number of teeth on the sun gear of the first planetary set.

3. The planetary reducer according to claim 2, characterized in that, The difference between the number of teeth on the ring gear of the second planetary set and the number of teeth on the ring gear of the first planetary set is greater than the difference between the number of teeth on the sun gear of the first planetary set and the number of teeth on the sun gear of the second planetary set.

4. The planetary reducer according to claim 2 or 3, characterized in that, The difference between the number of teeth on the ring gear of the second planetary gear set and the number of teeth on the sun gear of the second planetary gear set is greater than the difference between the number of teeth on the ring gear of the first planetary gear set and the number of teeth on the sun gear of the first planetary gear set.

5. The planetary reducer according to any one of claims 2-4, characterized in that, The number of teeth on the planetary gears of the second planetary gear set is greater than the number of teeth on the planetary gears of the first planetary gear set.

6. The planetary reducer according to any one of claims 2-5, characterized in that, The sun gear of the first planetary gear set has 54 teeth, the ring gear of the first planetary gear set has 110 teeth, the sun gear of the second planetary gear set has 52 teeth, and the ring gear of the second planetary gear set has 158 teeth.

7. The planetary reducer according to any one of claims 2-6, characterized in that, The center distance between the ring gear of the second planetary set and the sun gear of the second planetary set is smaller than the center distance between the ring gear of the first planetary set and the sun gear of the first planetary set.

8. The planetary reducer according to claim 1, characterized in that, The sun gear of the first planetary gear set is used to receive power, the planet carrier of the first planetary gear set is used to drive the drive of one wheel, the ring gear of the first planetary gear set is used to drive the drive of the sun gear of the second planetary gear set, and the ring gear of the second planetary gear set is used to drive the drive of the other wheel, wherein: The number of teeth on the gear ring of the second planetary set is greater than the number of teeth on the gear ring of the first planetary set.

9. The planetary reducer according to claim 8, characterized in that, The ratio of the number of teeth on the ring gear of the second planetary gear set to the number of teeth on the sun gear of the second planetary gear set is greater than the ratio of the number of teeth on the ring gear of the first planetary gear set to the number of teeth on the sun gear of the first planetary gear set.

10. The planetary reducer according to any one of claims 1-9, characterized in that, The plurality of planetary gear sets also includes a third planetary gear set, which is used to transmit the power output by the drive motor of the electric vehicle to the first planetary gear set. The difference between the transmission ratio of the first planetary gear set and the transmission ratio of the second planetary gear set is less than the difference between the transmission ratio of the first planetary gear set or the transmission ratio of the second planetary gear set and the transmission ratio of the third planetary gear set.

11. The planetary reducer according to claim 10, characterized in that, The ratio of the number of teeth on the ring gear to the number of teeth on the sun gear in each of the first and second planetary sets is less than the ratio of the number of teeth on the ring gear to the number of teeth on the sun gear in the third planetary set.

12. The planetary reducer according to any one of claims 1-11, characterized in that, The housing of the planetary reducer is used to accommodate the first planetary gear set and the second planetary gear set. The planet carrier or the gear ring of the second planetary gear set is used to fix the housing of the planetary reducer. The first planetary gear set is spaced apart from the housing of the planetary reducer.

13. The planetary reducer according to any one of claims 1-12, characterized in that, The difference between the gear ratio of the second planetary gear set and the gear ratio of the first planetary gear set is greater than or equal to 0.005% of the gear ratio of the first planetary gear set.

14. A powertrain, characterized in that, The powertrain includes a drive motor and a planetary gearbox as described in any one of claims 1-13, wherein the drive motor is used to drive the planetary gearbox.

15. An electric vehicle, characterized in that, The electric vehicle includes a power battery and a powertrain as described in claim 14, the powertrain being used to receive power from the power battery and to drive the wheels of the electric vehicle; or, The electric vehicle includes a power battery and a planetary reducer as described in any one of claims 1-13, the planetary reducer being used to drive the wheels of the electric vehicle.

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