Electric drive system

Abstract

The present invention discloses an electric drive system, comprising a motor, an input shaft, a first gear, a planetary gear system, a brake, a second gear set, a third gear set, a synchronizer, an output shaft and a differential mechanism, wherein the motor is connected to the input shaft, the first gear is fixedly arranged on the input shaft, the planetary gear system is rotatably arranged on the output shaft, the first gear is meshed with the ring gear of the planetary gear system, the brake is connected to the sun gear, the planet carrier is connected to the second gear set, the second gear set is rotatably arranged on the input shaft and the output shaft, and is fixedly connected to the third gear set, the third gear set is rotatably arranged on the input shaft and the output shaft, and is connected to the differential mechanism, and the synchronizer is slidably arranged on the input shaft, and is selectively connected to the second gear set or the third gear set. This solution can realize three-speed drive, broadening the gear selection range of the electric drive system. It can also greatly reduce the internal installation space of the electric drive system, making the internal structure of the electric drive system more compact.

Description

Technical Field

[0001] The present invention relates to the technology in the field of pure electric vehicles, and in particular to an electric drive system. Background Art

[0002] Pure electric vehicles refer to vehicles that use an onboard power source as a driving force and use an electric motor to drive the wheels. As their impact on the environment is relatively small compared to internal combustion engine vehicles, their prospects are widely optimistic. Considering the requirements of motor power density and layout space, the electric drive system of pure electric vehicles is developing in the direction of integration and multi-gear.

[0003] The electric drive system in the prior art usually has one or two gears, and its gear selection range is limited, which makes the efficient working area of ​​the motor narrow. In addition, the electric drive system will be equipped with multiple motors, or multiple synchronizers and other components to obtain more gears. Such a large number of components will increase the installation space of the electric drive system. In addition, the arrangement of each shaft in the electric drive system is relatively scattered, which will also take up more installation space. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an electric drive system in order to overcome the defects of the electric drive system in the prior art, that is, the gear selection range is limited and the large number of arranged components increases the installation space.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] An electric drive system includes a motor, an input shaft, a first gear, a planetary gear system, a brake, a second gear set, a third gear set, a synchronizer, an output shaft and a differential mechanism.

[0007] The motor is connected to the input shaft, and the first gear is fixed on the input shaft.

[0008] The planetary gear train includes a sun gear, planetary gears meshing with the sun gear, a ring gear meshing with the planetary gears, and a planet carrier connected to the planetary gears. The planetary gear train is rotatably disposed on the output shaft, and the first gear is meshed with the ring gear of the planetary gear train.

[0009] The brake is connected to the sun gear, and the planet carrier is connected to the second gear set.

[0010] The second gear set is rotatably disposed on the input shaft and the output shaft, and is fixedly connected to the third gear set.

[0011] The third gear set is rotatably disposed on the input shaft and the output shaft, and is connected to the differential mechanism.

[0012] The synchronizer is slidably disposed on the input shaft and is selectively connected to the second gear set or the third gear set.

[0013] Preferably, the second gear set includes a second driving tooth and a second passive tooth meshing with each other, the second driving tooth is rotatably provided on the input shaft, and the second passive tooth is rotatably provided on the output shaft, and the third gear set includes a third driving tooth and a third passive tooth meshing with each other, the third driving tooth is rotatably provided on the input shaft, the third passive tooth is rotatably provided on the output shaft, and the second passive tooth is fixedly connected to the third passive tooth.

[0014] Preferably, the synchronizer selectively engages with the second driving tooth or the third driving tooth.

[0015] Preferably, the differential mechanism comprises a differential arranged on the output shaft, and the third passive tooth is connected to the differential.

[0016] Preferably, a bearing is respectively arranged between the second driving tooth and the third driving tooth and the input shaft, and a bearing is also respectively arranged between the sun gear and the second driven tooth and the output shaft.

[0017] The technical effect obtained by the present invention is that the present solution can realize three-speed drive through the connection relationship and matching relationship between the motor, the input shaft, the first gear, the planetary gear system, the brake, the second gear set, the third gear set, the synchronizer, the output shaft and the differential mechanism, thereby broadening the gear selection range of the electric drive system. In addition, the present solution has only one motor and one synchronizer, and the differential mechanism is arranged on the output shaft, which can greatly reduce the internal installation space of the electric drive system, making the internal structure of the electric drive system more compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of an electric drive system having a first gear power flow direction indicator according to embodiment 1 of the present invention.

[0019] Figure 2 This is a schematic structural diagram of an electric drive system with a second-gear power flow direction indication according to embodiment 1 of the present invention.

[0020] Figure 3 This is a schematic structural diagram of an electric drive system with three-speed power flow direction indication according to embodiment 1 of the present invention. DETAILED DESCRIPTION

[0021] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0022] Embodiment 1:

[0023] This embodiment provides an electric drive system, which can be installed on a pure electric vehicle. Figure 1-3 As shown, it includes a motor 1, an input shaft 2, a first gear 3, a planetary gear system 4, a brake 5, a second gear set 6, a third gear set 7, a synchronizer 8, an output shaft 9 and a differential mechanism.

[0024] The motor 1 is connected to the input shaft 2 , and the first gear 3 is fixed on the input shaft 2 to rotate synchronously with the input shaft 2 .

[0025] The planetary gear train 4 includes a sun gear 41, a planetary gear 42 meshing with the sun gear 41, a ring gear 43 meshing with the planetary gear 42, and a planet carrier 44 connected to the planetary gear 42. The planetary gear train 4 is rotatably disposed on the output shaft 9, and specifically, the sun gear 41 of the planetary gear train 4 is disposed on the output shaft 9 via a needle bearing 45.

[0026] The first gear 3 meshes with the ring gear 43 of the planetary gear train 4 .

[0027] The brake 5 is connected to the sun gear 41 to fix or rotate the sun gear 41 .

[0028] The second gear set 6 is rotatably disposed on the input shaft 2 and the output shaft 9. Specifically, the second gear set 6 includes a second active tooth 61 and a second passive tooth 62 meshing with each other, the second active tooth 61 is disposed on the input shaft 2 via a needle bearing 63, and the second passive tooth 62 is rotatably disposed on the output shaft 9 via a needle bearing 64.

[0029] The planet carrier 44 is connected to the second gear set 6 , specifically, connected to the second driven gear 62 in the second gear set 6 .

[0030] The third gear set 7 is rotatably disposed on the input shaft 2 and the output shaft 9. Specifically, the third gear set 7 includes a third driving tooth 71 and a third passive tooth 72 meshing with each other, the third driving tooth 71 is rotatably disposed on the input shaft 2 through a needle bearing 73, and the third passive tooth 72 is rotatably disposed on the output shaft 9.

[0031] The second gear set 6 is fixedly connected to the third gear set 7 , specifically, the second passive gear 62 is fixedly connected to the third passive gear 72 .

[0032] The differential mechanism includes a differential 10 disposed on the output shaft. The third gear set 7 is connected to the differential mechanism, and specifically, the third driven gear 72 is connected to the differential 10 .

[0033] The synchronizer 8 is slidably disposed on the input shaft 2 and is selectively connected to the second gear set 6 or the third gear set 7. Specifically, the synchronizer 8 is selectively engaged with the second passive gear 62 or the third passive gear 72.

[0034] In order to enable those skilled in the art to better understand the technical solution of the present application, the present embodiment provides a detailed description of the power flow of the electric drive system: when a larger speed ratio is required for starting a car or starting on a slope, the first gear is used for driving. Figure 1 The direction of power flow is indicated by the arrow in the middle. The brake 5 is engaged to fix the sun gear 41, the synchronizer 8 is in the middle position, and no gear is engaged. The motor 1 drives the input shaft 2 to rotate, and the first gear 3 meshes with the ring gear 43 of the planetary gear train 4 to form the first stage of reduction. Inside the planetary gear train 4, since the sun gear 41 is fixed, the ring gear 43 is the active component, and the planetary carrier 44 outputs, forming the second stage of reduction. This type of planetary gear train achieves speed reduction and torque increase. The planetary carrier 44 is fixedly connected to the second passive tooth 62, and the second passive tooth 62 is fixedly connected to the third passive tooth 72, so the planetary carrier 44 can directly drive the differential 10 to output. Since the synchronizer 8 is not engaged, the second active tooth 61 and the third active tooth 71 are empty, so these two gears are not affected.

[0035] After the speed increases, the torque is not needed, and the gear can be raised, that is, two-gear drive. Figure 2 The arrow in the middle indicates the power flow direction. At this time, the brake 5 is disconnected, the synchronizer 8 moves right, that is, it is in the second gear, and the third active gear 71 and the third passive gear 72 form the first stage of reduction, so the motor torque directly drives the differential 10 to output after passing through the gear pair.

[0036] Since the second driving tooth 61 is empty at this time, it is not affected.

[0037] The brake 5 is disconnected, and the sun gear 41 is not constrained. The torque of the differential 10 is transmitted back to the planetary carrier 44, and the first gear 3 drives the ring gear 43 to rotate. However, since no parts in the planetary gear system 4 are fixed at this time, and no two parts are connected together, the planetary gear system 4 is not constrained and will not be affected.

[0038] After reaching high speed, you can shift into third gear. Figure 3 The arrow in the middle indicates the direction of power flow. At this time, the brake 5 is disconnected, the synchronizer 8 moves to the left, that is, the third gear is engaged, the second active gear 61 and the second passive gear 62 form the first stage of reduction, and because the second passive gear 62 and the third passive gear 72 are fixedly connected, the motor torque directly drives the differential 10 to output after passing through the gear pair.

[0039] Since the third active tooth 71 is empty at this time, it is not affected. The planetary gear train 4 is not subject to any constraints and will not be affected. The driving principle of the third gear is the same as that of the second gear.

[0040] In neutral, the synchronizer 8 is in the middle position, that is, no gear is engaged, the second active gear 61 and the third active gear 71 are idling. The brake 5 is also in a disconnected state, the first gear 3 drives the ring gear 43 to rotate, because there is no fixed part in the planetary gear system 4, and no two parts are connected together, the planet carrier 44 is in a free state, no speed or low speed output.

[0041] To achieve speed reduction, usually a small gear drives a large gear to achieve speed reduction, which is common knowledge in the art.

[0042] This embodiment can realize three-speed drive through the connection and matching relationship between the motor, input shaft, first gear, planetary gear system, brake, second gear set, third gear set, synchronizer, output shaft and differential mechanism. Compared with the single-speed system in the prior art, the three-speed electric drive system takes into account both the axle load torque and the maximum vehicle speed, and the higher speed ratio provides the possibility for motor miniaturization and integration. In addition, the three-speed drive system can compensate for the power drop caused by the increase in speed by transferring the working point in the high-speed zone to the low-speed zone, bringing about an improvement in efficiency, broadening the high-efficiency zone of the motor, and improving the power and economy of the whole vehicle.

[0043] In addition, this embodiment has only one motor and one synchronizer, and the differential mechanism is arranged on the output shaft, which can greatly reduce the internal installation space of the electric drive system and make the internal structure of the electric drive system more compact.

[0044] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. An electric drive system, It is characterized in that It includes a motor, an input shaft, a first gear, a planetary gear system, a brake, a second gear set, a third gear set, a synchronizer, an output shaft and a differential mechanism. The motor is connected to the input shaft, and the first gear is fixed on the input shaft. The planetary gear train includes a sun gear, a planetary gear meshing with the sun gear, a ring gear meshing with the planetary gear, and a planet carrier connected with the planetary gear. The planetary gear train is rotatably arranged on the output shaft. The first gear meshes with the ring gear of the planetary gear train. The brake is connected to the sun gear, and the planet carrier is connected to the second gear set. The second gear set is rotatably disposed on the input shaft and the output shaft, and is fixedly connected to the third gear set. The third gear set is rotatably disposed on the input shaft and the output shaft and is connected to the differential mechanism. The synchronizer is slidably disposed on the input shaft and selectively connected to the second gear set or the third gear set. Among them, the second gear set includes a second active tooth and a second passive tooth meshing with each other, the second active tooth is rotatably provided on the input shaft, and the second passive tooth is rotatably provided on the output shaft, the third gear set includes a third active tooth and a third passive tooth meshing with each other, the third active tooth is rotatably provided on the input shaft, and the third passive tooth is rotatably provided on the output shaft, the second passive tooth is fixedly connected to the third passive tooth, and the planet carrier is fixedly connected to the second passive tooth.

2. The electric drive system according to claim 1, It is characterized in that The synchronizer selectively engages with the second driving tooth or the third driving tooth.

3. The electric drive system according to claim 1, It is characterized in that The differential mechanism comprises a differential arranged on the output shaft, and the third driven tooth is connected to the differential.

4. The electric drive system according to any one of claims 1 to 3, It is characterized in that A bearing is respectively arranged between the second driving tooth and the third driving tooth and the input shaft, and a bearing is also respectively arranged between the sun gear and the second driven tooth and the output shaft.

Images