A two-speed rear axle power system for pure electric vehicles

Abstract

The present invention discloses a two-speed rear axle power system for a pure electric vehicle, comprising a motor, a motor shaft, a clutch, a one-way clutch, an inner shaft, an outer shaft, a planetary row, a rear sun gear, a rear planetary wheel and an output shaft; the planetary row comprises: a ring gear, a front planetary wheel, a front sun gear, a planetary shaft and a planetary carrier. By controlling the outer race and the inner race of the one-way clutch to engage and disengage, a two-speed power switching is formed. The first-speed power path is provided by a drive motor 1, and passes through the motor shaft, clutch, outer shaft, front sun gear, front planetary wheel, planetary shaft and planetary carrier in sequence, and is output from the output shaft; the second-speed power will add a path provided by the drive motor at the same time, and passes through the motor shaft, clutch, inner shaft, rear sun gear, rear planetary wheel, planetary shaft and planetary carrier in sequence, and is output from the output shaft. This system simplifies the clutch structure, is simple to control, reduces costs, and realizes the two-speed rear axle power function of the electric vehicle at the same time.

Description

Technical Field

[0001] The invention relates to a pure electric vehicle, and in particular to a two-speed rear axle power system of a pure electric vehicle. Background Art

[0002] The two-speed rear axle power system of a pure electric vehicle in the prior art includes a drive motor, a planetary gear, a rear sun gear, a rear planetary gear, a first clutch, a second clutch and an output shaft; wherein the planetary gear includes a front sun gear, a ring gear, a planetary carrier and a front planetary gear; the drive motor transmits power to the front sun gear and the rear sun gear respectively through the first clutch and the second clutch to realize the two-speed function. Therefore, two clutches are used to realize the power transmission of the two gears. The structure of the two clutches is complex and occupies a large space. The control system required to meet the power switching of the two gears is relatively complex; the engagement and disconnection of the two clutches during the gear switching in order to reduce overload slippage, the control system has high requirements. In order to meet the gear shifting performance requirements, the two clutches often use wet clutches, resulting in complex structure and high cost. Summary of the invention

[0003] The invention discloses a two-speed rear axle power system for a pure electric vehicle, which simplifies the clutch structure, makes the control simple, reduces the cost, and realizes the two-speed rear axle power function of the electric vehicle.

[0004] The present invention discloses a two-speed rear axle power system for a pure electric vehicle, comprising a motor, a motor shaft, a clutch, a one-way clutch, an inner shaft, an outer shaft, a planetary gear, a rear sun gear, a rear planetary gear, and an output shaft;

[0005] The planetary gear set comprises: a ring gear, a front planetary gear, a front sun gear, a planetary shaft and a planetary carrier; the front sun gear and the rear sun gear are arranged side by side, the front planetary gear and the rear planetary gear are fixedly connected and are loosely sleeved on the planetary shaft of the planetary carrier of the planetary gear set in parallel, the front sun gear and the rear sun gear are meshed with the front planetary gear and the rear planetary gear respectively, and the front planetary gear is meshed with the ring gear;

[0006] The motor power is output through the motor shaft;

[0007] The clutch is located between the drive motor and the planetary gear, the outer hub of the clutch is fixedly connected to the output end of the motor shaft, and the inner hub of the clutch is fixedly connected to the input end of the outer shaft;

[0008] The inner shaft is sleeved in the outer shaft, and the inner shaft extends out of both ends of the outer shaft, and its input end is fixedly connected to the outer hub of the clutch, and its output end is fixedly connected to the rear sun gear; the output end of the outer shaft is fixedly connected to the front sun gear;

[0009] The one-way clutch is arranged outside the gear ring, and the outer seat ring of the one-way clutch is fixed, and the inner seat ring of the one-way clutch 4 is fixedly connected with the gear ring;

[0010] The output end of the planet carrier of the planetary gear is fixedly connected with the output shaft.

[0011] Furthermore, the number of gear teeth of the front sun gear 7 is greater than that of the rear sun gear, and the number of gear teeth of the front planetary gears is less than that of the rear planetary gears.

[0012] Furthermore, the clutch is a dry clutch.

[0013] Furthermore, the first clutch is a dry electromagnetic clutch.

[0014] Furthermore, the clutch is a dry hydraulic clutch.

[0015] The beneficial technical effects of the present invention are:

[0016] 1) By setting a clutch and a one-way clutch, a clutch that needs to be controlled and a one-way clutch that does not need to be controlled are used to replace the general double clutch to achieve two-speed power transmission; it has a simple structure, small size and low cost;

[0017] 2) Gear shifting is achieved by the combination and disconnection control of the clutch and the one-way clutch. Since the one-way clutch has the ability to transmit torque in one direction, overload slippage caused by dual-clutch gear shifting is avoided. The control strategy of the one-way clutch and the clutch is simpler, the stability is improved, and the cost is reduced.

[0018] 3) The number of gear teeth of the front sun gear 7 is greater than that of the rear sun gear 12, and the number of gear teeth of the front planetary gear 8 is less than that of the rear planetary gear 11. A larger transmission ratio can be achieved, and the second gear speed is increased, so that the power system has a larger speed range, and thus the system has higher efficiency and better economic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] See also Figure 1 A two-speed rear axle power system of a pure electric vehicle includes: a motor 1, a motor shaft 2, a clutch 3, a one-way clutch 4, an inner shaft 6, an outer shaft 5, a planetary gear, a rear sun gear 12, a rear planetary gear 11, and an output shaft 15.

[0022] The planetary gear set includes: a ring gear 10, a front planetary gear 8, a front sun gear 7, a planetary shaft 13 and a planetary carrier 14. The front sun gear 7 and the rear sun gear 12 are arranged side by side, the front planetary gear 8 and the rear planetary gear 11 are fixedly connected and are loosely sleeved on the planetary shaft 13 of the planetary carrier 14 of the planetary gear set side by side, the front sun gear 7 and the rear sun gear 12 are meshed with the front planetary gear 8 and the rear planetary gear 11 respectively, and the front planetary gear 8 is meshed with the ring gear 10. The number of gear teeth of the front sun gear 7 is greater than that of the rear sun gear 12, and the number of gear teeth of the front planetary gear 8 is less than that of the rear planetary gear 11.

[0023] The power of motor 1 is output through motor shaft 2.

[0024] The clutch 3 is located between the driving motor 1 and the planetary gear. The outer hub of the clutch 3 is fixedly connected to the output end of the motor shaft 2 , and the inner hub of the clutch 3 is fixedly connected to the input end of the outer shaft 5 .

[0025] The inner shaft 6 is sleeved in the outer shaft 5 , and extends out of both ends of the outer shaft 5 . The input end of the inner shaft 6 is fixedly connected to the outer hub of the clutch 3 , and the output end is fixedly connected to the rear sun gear 12 . The output end of the outer shaft 5 is fixedly connected to the front sun gear 7 .

[0026] The one-way clutch 4 is arranged outside the gear ring 10, and the outer race of the one-way clutch 4 is fixed, and the inner race of the one-way clutch 4 is fixedly connected with the gear ring 10. The outer race of the one-way clutch 4 is fixed on the vehicle through the frame 9.

[0027] The output end of the planet carrier 14 of the planetary gear is fixedly connected to the output shaft 15 .

[0028] Clutch 3 can be selected as: dry clutch, dry electromagnetic clutch or dry hydraulic clutch. Clutch 3 is a dry clutch, which has low manufacturing cost, simple control and high mechanical transmission efficiency. Clutch 3 is a dry electromagnetic clutch, which can be connected to the electronic control system of the car and has extremely fast response. Clutch 3 is a dry hydraulic clutch, which has simple and stable control of electromagnetic clutch and hydraulic clutch. Dry hydraulic clutch can be connected to the hydraulic system of the car, can transmit large torque and has smaller volume.

[0029] The structure uses a clutch that needs to be controlled and a one-way clutch that does not need to be controlled to replace the general double clutch to achieve two-speed power transmission; it has a simple structure, small size and low cost;

[0030] Gear switching is achieved by the combination and disconnection control of the clutch and the one-way clutch. Since the one-way clutch has the ability to transmit torque in one direction, it avoids overload and slippage during dual-clutch shifting. The control strategy of the one-way clutch and the clutch is simpler than that of the dual-clutch, which improves stability and reduces costs.

[0031] The number of gear teeth of the front sun gear 7 is greater than that of the rear sun gear 12, and the number of gear teeth of the front planetary gear 8 is less than that of the rear planetary gear 11. A larger transmission ratio can be achieved, and the second gear speed is increased, so that the power system has a larger speed range, and thus the system has higher efficiency and better economic performance.

[0032] Working principle:

[0033] First gear working mode: the drive motor 1 works, the outer drum and inner hub of the clutch 3 are disconnected, and the outer race and inner race of the one-way clutch 4 are combined; the power of the drive motor 1 is transmitted to the rear sun gear 12 through the inner shaft 6, and the front planetary gear 8 and the rear planetary gear 11 rotate around the planetary gear shaft 13 of the planetary carrier 14 on the one hand, and revolve around the center line of the rear sun gear 12 at the same time. When the outer race, inner race and gear ring 10 of the one-way clutch 4 are fixed and do not rotate, the power of the drive motor 1 passes through the motor shaft 2, the inner shaft 6, the rear sun gear 12, the rear planetary gear 11, the front planetary gear 8, the planetary shaft 13 and the planetary carrier 14 in sequence, and finally outputs the power through the output shaft 15. At this time, the first gear transmission ratio is formed. First gear power route: drive motor 1, motor shaft 2, inner shaft 6, rear sun gear 12, rear planetary gear 11, front planetary gear 8, planetary shaft 13, planetary carrier 14, output shaft 15.

[0034] Second gear working mode: the drive motor 1 is working, the outer drum and inner hub of the clutch 3 are combined, and the outer race and inner race of the one-way clutch 4 are disconnected; one path of power is transmitted to the outer shaft 5 and the front sun gear 7 via the clutch 3, and the other path of power is transmitted to the rear sun gear 12 via the inner shaft 6; the two power routes from the drive motor 1 are transmitted to the front sun gear 7 and the rear sun gear 11 at the same time, so that the front sun gear 7, the front planetary gear 8, the planetary shaft 13, the planetary carrier 14 and the rear sun gear 12 and the rear planetary gear 11 are fixed together and rotate around the center line of the front sun gear 7, and finally the power is output through the output shaft 15. At this time, the second gear transmission ratio is formed.

[0035] The second gear power line is:

[0036] The first power is provided by the driving motor 1, passes through the motor shaft 2, the clutch 3, the outer shaft 5, the front sun gear 7, the front planetary gear 8, the planetary shaft 13 and the planetary carrier 14 in sequence, and is output from the output shaft 15;

[0037] The second power is provided by the driving motor 1 at the same time, passes through the motor shaft 2, the clutch 3, the inner shaft 6, the rear sun gear 12, the rear planetary gear 11, the planetary shaft 13 and the planetary carrier 14 in sequence, and is output from the output shaft 15.

[0038] Gear shifting: When the car is running in the first gear, the automatic control unit of the transmission knows the driving state of the vehicle according to the relevant sensors, and then makes a judgment. If acceleration is required, it will enter the second gear. Specifically, when the vehicle is running in the first gear and reaches the shift point where it needs to change to the second gear, the clutch 3 is gradually engaged, the planetary gear and the rear sun gear 12 and the rear planetary gear 11 rotate together, the inner seat ring of the one-way clutch 4 is disengaged from the lock of the outer seat ring and rotates, the inner seat ring and the outer seat ring of the one-way clutch 4 are gradually disconnected, and the clutch 3 is further engaged until it is fully engaged, the whole gear shifting is completed, and the vehicle is shifted into the second gear. The process of the vehicle shifting from the second gear to the first gear is exactly the opposite of the process of shifting into the second gear. Specifically, when the vehicle is running in the second gear and needs to change to the first gear, the clutch 3 in the engaged state is gradually disconnected, and the one-way clutch 4 in the disconnected state is gradually engaged until the clutch 3 is completely disconnected and the one-way clutch 4 is fully engaged, the whole gear shifting is completed, and the vehicle is shifted into the first gear.

[0039] When the car is driving in the first gear and encounters a special road section, the wheel speed is too high and reverse drag occurs. At this time, the speed of the drive motor 1 can be reduced, and the clutch 3 can be controlled to switch to the second gear to achieve stable power transmission.

Claims

1. A two-speed rear axle power system for a pure electric vehicle, characterized in that: It comprises a motor (1), a motor shaft (2), a clutch (3), a one-way clutch (4), an inner shaft (6), an outer shaft (5), a planetary gear, a rear sun gear (12), a rear planetary gear (11), and an output shaft (15), wherein the clutch (3) is a dry clutch; The planetary gear set comprises: a ring gear (10), a front planetary gear (8), a front sun gear (7), a planetary shaft (13) and a planetary carrier (14); the front sun gear (7) and the rear sun gear (12) are arranged in parallel on the left and right sides; the front planetary gear (8) and the rear planetary gear (11) are fixedly connected and are loosely sleeved on the planetary shaft (13) of the planetary carrier (14) of the planetary gear set in parallel on the left and right sides; the front sun gear 7 and the rear sun gear (12) are meshed with the front planetary gear (8) and the rear planetary gear (11) respectively; the front planetary gear (8) is meshed with the ring gear (10); the number of gear teeth of the front sun gear (7) is greater than the number of gear teeth of the rear sun gear (12); and the number of gear teeth of the front planetary gear (8) is less than the number of gear teeth of the rear planetary gear (11); The power of the motor (1) is output through the motor shaft (2); The clutch (3) is located between the drive motor (1) and the planetary gear, the outer hub of the clutch (3) is fixedly connected to the output end of the motor shaft (2), and the inner hub of the clutch (3) is fixedly connected to the input end of the outer shaft (5); The inner shaft (6) is sleeved in the outer shaft (5), the inner shaft (6) extends out of both ends of the outer shaft (5), the input end of the inner shaft (6) is fixedly connected to the outer hub of the clutch (3), and the output end is fixedly connected to the rear sun gear (12); the output end of the outer shaft (5) is fixedly connected to the front sun gear (7); The one-way clutch (4) is arranged outside the gear ring (10), and the outer seat ring of the one-way clutch (4) is fixed, and the inner seat ring of the one-way clutch (4) is fixedly connected to the gear ring (10); The output end of the planet carrier (14) of the planetary gear is fixedly connected to the output shaft (15).

Images