Hub drive structure with static through-shaft support, driving method for two-wheeled electric vehicle

Abstract

The static through shaft support hub drive structure of the application, the motor is coaxially arranged on the left side of the planetary gear set, the static through shaft fixed with the vehicle frame penetrates the motor and the planetary gear set, forming the exposed installation of the motor supported on the static through shaft and independent of the hub, effectively improving the air cooling heat dissipation capacity of the motor, improving the convenience of disassembly and maintenance of the hub and the motor. The static through shaft, the shell of the motor and the inner ring gear are fixed as a whole, realizing the static support of the motor and the planetary gear set by the static through shaft, the static through shaft has high stability and long fatigue life, is not easy to bend and deform, improves the support reliability of the motor and the planetary gear set, reduces the load of the planetary gear set during operation, reduces the wear of the planetary gear and the bearing, improves the transmission reliability and stability of the transmission assembly under the working condition of frequent start and stop and high torque, and prolongs the service life. The hub is assembled on the planetary carrier, forming a whole circle support with larger inner diameter for the hub, improving the stability and reliability of the hub assembly.

Description

Technical Field

[0001] This invention relates to a static through-shaft supported hub drive structure for hub drive of a two-wheeled electric vehicle, and also to a driving method for a two-wheeled electric vehicle. Background Technology

[0002] With the implementation of the new national standard, the demand for high-power two-wheeled electric vehicles (electric motorcycles) has increased. Planetary reduction gears (planetary sets) have become the preferred choice for electric motorcycle reducers due to their compact structure, large transmission ratio, and strong load-bearing capacity. Traditional hub motor planetary gear schemes typically employ a "sun gear input, planet carrier output, fixed gear ring" or similar structural pattern. Electric motorcycles generally use hub motors as the drive component, which enclose the motor inside the hub, which is mounted on the main shaft (axle). The motor shaft drives the main shaft through the planetary reduction gear, thus achieving propulsion. The shortcomings of this integrated drive structure are: 1. The motor has poor heat dissipation performance when installed inside the wheel hub, and the wheel hub needs to be disassembled and installed at the same time, which makes disassembly and maintenance inconvenient.

[0003] 2. The radial support capacity of the motor and planetary gear set is poor, and the structural stability is insufficient. In order to improve the support capacity, an axial through hole is opened on the motor shaft, and the main shaft passes through the axial through hole. The motor is mounted on the main shaft through bearings, and the planetary gear set is mounted on the main shaft. The planetary carrier is connected to the main shaft for transmission. The main shaft supports the motor and planetary gear set. However, under the conditions of frequent start-stop and high torque, the main bearing is subjected to dynamically changing axial and radial fatigue loads. After long-term operation, the main shaft will bend and deform, which will affect the reliability of transmission, accelerate the wear of gears and bearings inside the planetary gear set, and also affect the normal operation of the wheels.

[0004] 3. The integrated structure of the motor, planetary gear set and hub is not compact enough, resulting in larger bearing and oil seal sizes, which increases costs and also affects the overall layout of the drive structure.

[0005] 4. The planetary gear set uses helical gear transmission. During the transmission process, the axial force on the planetary gear set will not only be transmitted to the main shaft, causing an increase in the axial load of the main shaft, but also cause an increase in the internal stress of the planetary gear set, accelerating wear. Summary of the Invention

[0006] The static through-shaft supported hub drive structure provided by this invention forms an exposed motor mounted on a static through-shaft, independent of the hub. This effectively improves the motor's air-cooling capacity and avoids simultaneous disassembly and assembly of the motor and hub, improving the convenience of disassembly and maintenance of both. The static through-shaft, motor housing, and internal gear ring are fixedly connected as a whole, achieving static support for the motor and planetary gear set using the static through-shaft. The static through-shaft has high stability, long fatigue life, and is not easily bent or deformed, improving the reliability of support for the motor and planetary gear set, reducing wear on the internal gears and bearings of the planetary gear set, improving the transmission reliability and stability of the transmission assembly under frequent start-stop and high torque conditions, extending its service life, and improving the stability and reliability of hub assembly. This invention also provides a driving method for a two-wheeled electric vehicle.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A hub drive structure supported by a static through shaft includes a motor and a planetary gear set. The planetary gear set includes a sun gear connected to the rotor of the motor, planet gears meshing with the sun gear, a planet carrier mounting the planet gears, and an internal gear ring with internal teeth meshing with the planet gears. The structure is characterized by further including a static through shaft fixed to the frame and passing through the motor and the planetary gear set along the central axis. The motor is coaxially arranged on the left side of the planetary gear set. The static through shaft, the motor housing, and the internal gear ring are fixedly connected as a whole. The wheel hub is mounted on the planet carrier and separated from the motor.

[0008] Optionally, the housing consists of a housing body and a housing end cover fixed to the right end of the housing body. The housing end cover is coaxially fixed with the internal gear ring. The right end of the rotor extends out of the housing end cover and is integrally formed with the sun gear. A left oil seal is press-fitted between the rotor and the housing end cover.

[0009] Optionally, the left end of the static through shaft extends out of the housing and is fixedly connected to the flange at the left end of the housing body, and the right end extends out of the planetary carrier. A right bearing supporting the planetary carrier and a right oil seal sealing the planetary carrier and the static through shaft are press-fitted onto the static through shaft.

[0010] Optionally, the planetary carrier is disposed in the internal gear ring, the right end of the planetary carrier extends out of the internal gear ring, the hub is fixed to the right end of the planetary carrier and is axially offset outside the internal gear ring, and the left bearing supporting the left end of the planetary carrier is press-fitted onto the outer casing end cover.

[0011] Optionally, the outer casing end cap is integrally formed with the inner gear ring, and an output oil seal is press-fitted between the right end of the inner gear ring and the planetary carrier.

[0012] Optionally, it also includes a hub support frame located on the right side of the outer casing end cover. The planetary carrier is set in the internal gear ring, and the internal gear ring is set in the hub support frame. The right end of the planetary carrier extends out of the internal gear ring. The right end of the hub support frame is splined and fitted onto the right end of the planetary carrier. The left end is supported on the internal gear ring by the left bearing. The hub is assembled on the hub support frame.

[0013] Optionally, the hub support frame includes a left support ring and a right support ring fixed to the right end of the left support ring by bolts. An annular cavity for accommodating the internal gear ring is formed between the left support ring and the right support ring. The left bearing is press-fitted onto the internal gear ring, the left support ring is press-fitted onto the left bearing, and the right support ring is splined and fitted onto the right end of the planetary carrier.

[0014] Optionally, a support bearing is press-fitted between the planetary carrier and the internal gear ring, and an output oil seal is press-fitted onto the left support ring to seal the space between the left support ring and the outer casing end cover.

[0015] Optionally, the internal gear ring is disposed in the planetary carrier, and a left bearing is press-fitted between the left end of the internal gear ring and the left end of the planetary carrier. An output oil seal is press-fitted onto the left end of the planetary carrier to seal the space between the planetary carrier and the outer casing end cover.

[0016] A driving method for a two-wheeled electric vehicle is characterized by: assembling a hub drive structure with static through-shaft support as described in any one of the claims on the rear wheel hub of the two-wheeled electric vehicle; starting the motor; transmitting the motor's power to the planetary carrier via the sun gear and planetary gears; and having the inner planetary carrier drive the hub to rotate, thereby achieving driving.

[0017] The beneficial effects of this invention are: The static through-shaft supported hub drive structure of the present invention has the motor coaxially mounted on the left side of the planetary gear set. The hub is mounted on the planetary carrier, separated from the motor. The static through-shaft, which is fixed to the frame, passes through the motor and the planetary gear set, forming an exposed installation where the motor is supported on the static through-shaft and is independent of the hub. Compared with the motor mounted in the hub, this effectively improves the motor's air-cooling heat dissipation capacity and avoids the simultaneous disassembly and assembly of the motor and hub, improving the convenience of disassembly and maintenance of the hub and motor. The motor is not limited by the hub size, and motors of different sizes can be selected according to the drive requirements to meet the drive needs of different application scenarios.

[0018] The static through shaft, motor housing, and internal gear ring are fixed together as a whole, and the static through shaft is fixed to the frame to ensure that the internal gear ring and the static through shaft are stationary. The planetary carrier is used as the power output end to drive the wheel hub to rotate, so that the static through shaft forms static support for the motor and planetary gear set. The static through shaft does not participate in the transmission and does not directly bear the axial and radial fatigue loads from the wheel. The static through shaft has high stability, long fatigue life, and is not easy to bend and deform, which improves the reliability of the support for the motor and planetary gear set, and avoids the wheel load from being transmitted to the planetary gear set through the static through shaft, reducing the load on the planetary gear set during operation, reducing the wear of the gears and bearings inside the planetary gear set, improving the transmission reliability and stability of the transmission assembly under frequent start-stop and high torque conditions, and extending its service life.

[0019] The wheel hub is mounted on a planetary carrier, which drives the wheel hub to rotate synchronously. Compared with the existing technology that uses a main shaft to drive the wheel hub to rotate, the planetary carrier is larger in size and provides full-circle support for the wheel hub with a larger inner diameter, thereby improving the stability and reliability of the wheel hub assembly. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the through-shaft supported hub electric drive transmission assembly of Embodiment 1.

[0021] Figure 2 This is a transmission principle diagram of the through-shaft supported hub electric drive transmission assembly in Example 1.

[0022] Figure 3 This is a schematic diagram of the through-shaft supported hub electric drive transmission assembly of Embodiment 2.

[0023] Figure 4 This is a schematic diagram of the through-shaft supported hub electric drive transmission assembly in Embodiment 3.

[0024] Figure 5 This is a transmission principle diagram of the through-shaft supported hub electric drive transmission assembly of Embodiment 2 or Embodiment 3. Detailed Implementation

[0025] The following is combined Figures 1-5 The embodiments of the present invention will be described in detail below. Example 1:

[0026] A static through-shaft supported hub drive structure includes a motor 1 and a planetary gear set 2. The planetary gear set 2 includes a sun gear 21 connected to the rotor 11 of the motor 1, planet gears meshing with the sun gear 21, a planet carrier 22 for mounting the planet gears, and an internal gear ring 23 whose internal teeth mesh with the planet gears. The structure is characterized by further including a static through-shaft 3 fixed to the frame and passing through the motor 1 and the planetary gear set 2 along the central axis. The motor 1 is coaxially arranged on the left side of the planetary gear set 2. The static through-shaft 3, the motor housing 12, and the internal gear ring 23 are fixedly connected as a whole. The wheel hub 4 is mounted on the planet carrier 22 and is separated from the motor 1.

[0027] In the static through-shaft supported hub drive structure described above, the motor 1 is coaxially mounted on the left side of the planetary gear set 2. The hub 4 is mounted on the planetary carrier 22, separated from the motor 1. The static through-shaft 3, which is fixed to the frame 100, passes through the motor 1 and the planetary gear set 2, forming an exposed installation where the motor is supported on the static through-shaft 3 and is independent of the hub 4. Compared with the motor installed inside the hub 4, this effectively improves the motor's air-cooling heat dissipation capacity and avoids the simultaneous disassembly and assembly of the motor and the hub, improving the convenience of disassembly and maintenance of the hub and motor. The motor is not limited by the hub size, and motors of different sizes can be selected according to the drive requirements to meet the drive needs of different application scenarios. The static through shaft 3, the motor housing 12, and the internal gear ring 23 are fixedly connected as a whole, and the static through shaft 3 is fixed on the frame 100, ensuring that the internal gear ring 23 and the static through shaft 3 remain stationary. The planetary carrier 22 serves as the power output end, driving the wheel hub 4 to rotate. This achieves static support for the motor 1 and the planetary gear set 2 using the static through shaft 3. The static through shaft 3 does not participate in the transmission and does not directly bear the axial and radial fatigue loads from the wheel. The static through shaft 3 has high stability, long fatigue life, and is not easily bent or deformed, improving the reliability of support for the motor 1 and the planetary gear set 2. It also prevents the wheel load from being transmitted to the planetary gear set through the static through shaft, reducing the load on the planetary gear set during operation, reducing wear on the gears and bearings inside the planetary gear set, improving the transmission reliability and stability of the transmission assembly under frequent start-stop and high torque conditions, and extending its service life. The wheel hub 3 is assembled on the planetary carrier 2, and the planetary carrier 2 drives the wheel hub to rotate synchronously. Compared with the existing structure where the main shaft drives the wheel hub to rotate, the planetary carrier is larger in size, providing a larger inner diameter full-circle support for the wheel hub, improving the stability and reliability of the wheel hub assembly.

[0028] The outer casing 12 consists of an outer casing body 121 and an outer casing end cap 122 fixed to the right end of the outer casing body 121. The outer casing end cap 122 is coaxially fixed with the internal gear ring 23. The right end of the rotor 11 extends out of the outer casing end cap 122 and is integrally formed with the sun gear 21. A left oil seal 123 is press-fitted between the rotor 11 and the outer casing end cap 122. As shown in the figure, the right side of the outer casing 12 is closed by the outer casing end cap 122. The outer casing end cap 122 is fixed to the internal gear ring 23 as a whole. The sun gear 21 is integrally formed at the right end of the rotor 11 extending out of the outer casing end cap 122. The static through shaft 3 is supported and positioned by the frame and passes through the rotor 11. The outer casing 12 is fixed with the static through shaft 3. The static through shaft 3 forms radial support for the outer casing 12. The bearing between the outer casing 12 and the rotor 11 forms radial support for the rotor 11, ensuring that the rotor 11 and the static through shaft 3 do not contact each other during operation.

[0029] The static through shaft 3 extends out of the outer casing 12 at its left end and is fixedly connected to the flange at the left end of the outer casing 121. Its right end extends out of the planetary carrier 22. A right bearing 5 supporting the planetary carrier 22 and a right oil seal 6 sealing the space between the planetary carrier 22 and the static through shaft 3 are press-fitted onto the static through shaft 4. Since the planetary carrier 22 needs to rotate while the static through shaft 3 needs to remain stationary, a right bearing 5 is press-fitted onto the static through shaft 3 to provide radial support to the planetary carrier, ensuring radial reliability of the planetary gear set 2. The right oil seal 6 seals the space between the planetary carrier 22 and the static through shaft 3, preventing lubricating oil from leaking out between them.

[0030] The planetary carrier 22 is housed within the internal gear ring 23, with its right end extending out of the internal gear ring 23. The hub 3 is fixed to the right end of the planetary carrier 22 and axially offset outside the internal gear ring 23. A left bearing 71 supporting the left end of the planetary carrier 22 is press-fitted onto the outer casing end cover 122. Figure 1 As shown, in this embodiment, the internal gear ring 23 serves as the outer shell of the planetary gear set 2. The right end of the planetary carrier 22 is supported on the static through shaft 3 by the right bearing 5, and the left end is supported on the outer shell end cover 122 by the left bearing 71. The outer shell end cover 122 and the static through shaft 3 are fixedly connected as a whole, ensuring the reliability of the radial support for the planetary carrier 22. The hub 3 is fixed to the planetary carrier 22 and is axially offset and sleeved on the outer circumference of the internal gear ring 2. The assembly structure of this embodiment is compact and has a small space occupancy rate.

[0031] The outer casing end cap 122 is integrally formed with the inner gear ring 23, and an output oil seal 124 is press-fitted between the right end of the inner gear ring 23 and the planetary carrier 22. In this embodiment, the inner gear ring 23 serves as the outer casing of the planetary gear set 2. The output oil seal 124 is press-fitted between the right end of the inner gear ring 23 and the planetary carrier 22 to prevent oil leakage from the inner gear ring 23. The output oil seal 124 is located on the inner ring of the right end of the inner gear ring 23, and its small size reduces costs. Example 2:

[0032] The differences from Implementation List 1 are as follows: (1) It also includes a hub support frame 8 located on the right side of the outer casing end cover 122. The internal gear ring 23 is set in the hub support frame 8. The right end of the hub support frame 8 is splined and fitted on the right end of the planetary carrier 22. The left end is supported on the internal gear ring 23 by the left bearing 72. The hub 3 is assembled on the hub support frame 8.

[0033] (2) The hub support frame 8 includes a left support ring 81 and a right support ring 82 fixed to the right end of the left support ring 81 by bolts. An annular cavity for accommodating the internal gear ring 23 is formed between the left support ring 81 and the right support ring 82. The left bearing 2 72 is press-fitted onto the internal gear ring 23, the left support ring 81 is press-fitted onto the left bearing 2 72, and the right support ring 82 is splined and fitted onto the right end of the planetary carrier 22.

[0034] (3) A support bearing 9 is press-fitted between the planetary carrier 22 and the internal gear ring 23, and an output oil seal 125 is press-fitted onto the left support ring 81 to seal between the left support ring 81 and the outer casing end cover 122.

[0035] In this embodiment, the planetary carrier 2 is also placed in the internal gear ring 23, and the right end of the planetary carrier 22 extends out of the internal gear ring 23. The difference from Embodiment 1 is that a hub support frame 8 is added outside the internal gear ring 23 to support the hub 3, improving the support rigidity of the hub 3. The hub support frame 8 forms a rigid support for the entire circumference of the hub, ensuring the reliability of the support and the stability of the assembly of the hub 2. The hub support frame 8 adopts a structure with a left support ring 81 and a right support ring 82 fixed separately. The left support ring 81 is supported by the left bearing 72 on the internal gear ring 23, and the right support ring 82 is splined and fitted onto the planetary carrier 22, forming a reliable radial support for the hub support frame 8. Figure 3 As shown in the figure, in this embodiment, a hub support frame 8 is used as the housing of the planetary gear set 2. The internal gear ring 23 is located in the hub support frame 8, and the planet carrier 8 is installed in the internal gear ring 23. The left end of the planet carrier 22 is suspended and separated from the internal gear ring 23, without contact. The left end of the internal gear ring 23 is fixedly connected to the outer casing end cover 122 or integrally formed. The right end is supported on the planet carrier 22 by a support bearing 9, and the planet carrier 22 is supported on the static through shaft 3 by a right bearing 5, thus achieving reliable radial support for the planetary gear set 2. In order to prevent the oil in the planetary gear set 2 from leaking out, an output oil seal 125 is press-fitted onto the left support ring 81 to seal between the left support ring 81 and the outer casing end cover 122. As can be seen from the figure, in this embodiment, the output oil seal 125 is press-fitted onto the left support ring 81, and its size is larger than that of the output oil seal 124 in embodiment one. Example 3:

[0036] The difference from Embodiment 1 is that the internal gear ring 23 is disposed in the planetary carrier 22, and a left bearing 3 73 is press-fitted between the left end of the internal gear ring 23 and the left end of the planetary carrier 22. An output oil seal 3 126 is press-fitted onto the left end of the planetary carrier 22 to seal the planetary carrier and the outer casing end cover. In this embodiment, the planetary carrier 22 serves as the housing of the planetary gear set 2. The internal gear ring 23 is disposed in the planetary carrier 22, and the left bearing 3 73 is press-fitted between the left end of the internal gear ring 23 and the left end of the planetary carrier 22, supporting the left end of the planetary carrier 22. The right end of the planetary carrier 22 is supported on the static through shaft 3 by the right bearing 5, forming effective radial support for the planetary carrier 22, which serves as the housing. In this embodiment, the planetary carrier 23 is designed as an integral outer structure that encloses the internal gear ring 23. Compared with Embodiment 2, the hub support frame 8 is omitted. The planetary carrier 23 with the integral outer structure directly supports the hub 3, forming a rigid support for the hub. This ensures the reliability of the hub 2's support and the stability of its assembly, while also simplifying the structure, making the entire drive structure more compact and lighter.

[0037] This invention also provides a driving method for a two-wheeled electric vehicle, characterized in that: a static through-shaft supported hub drive structure as described above is installed on the rear wheel hub of the two-wheeled electric vehicle; when the motor 1 is started, the power of the motor is transmitted to the planet carrier 22 via the sun gear 21 and planet gears; the inner planet carrier 22 drives the wheel hub 3 to rotate, thus achieving drive. The driving method for the two-wheeled electric vehicle described above, by installing the static through-shaft supported hub drive structure on the rear wheel hub of the two-wheeled electric vehicle, improves the transmission reliability and stability of the two-wheeled electric vehicle under frequent start-stop and high torque conditions, enhances the adaptability of the two-wheeled electric vehicle to various operating conditions, extends the normal service life of the wheels, and expands the application scenarios of two-wheeled electric vehicles.

[0038] The technical solutions of the embodiments of the present invention have been fully described above with reference to the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A statically supported hub drive structure, comprising a motor and a planetary gear set, wherein the planetary gear set comprises a sun gear connected to the rotor of the motor, planet gears meshing with the sun gear, a planet carrier assembling the planet gears, and an internal gear ring with internal teeth meshing with the planet gears, characterized in that: It also includes a static through shaft that is fixed to the frame and runs through the motor and planetary gear set along the central axis. The motor is coaxially located on the left side of the planetary gear set. The static through shaft, the motor housing, and the internal gear ring are fixed together as a whole. The wheel hub is mounted on the planetary carrier and is separated from the motor.

2. The hub drive structure with static through-shaft support according to claim 1, characterized in that: The outer casing consists of an outer casing body and an outer casing end cover fixed to the right end of the outer casing body. The outer casing end cover is coaxially fixed with the internal gear ring. The right end of the rotor extends out of the outer casing end cover and is integrally formed with the sun gear. A left oil seal is press-fitted between the rotor and the outer casing end cover.

3. The hub drive structure with static through-shaft support according to claim 2, characterized in that: The left end of the static through shaft extends out of the outer casing and is fixedly connected to the flange at the left end of the outer casing body. The right end extends out of the planetary carrier. The right bearing supporting the planetary carrier and the right oil seal sealing the planetary carrier and the static through shaft are press-fitted onto the static through shaft.

4. The hub drive structure with static through-shaft support according to claim 3, characterized in that: The planetary carrier is set in the internal gear ring, the right end of the planetary carrier extends out of the internal gear ring, the hub is fixed to the right end of the planetary carrier and is axially offset outside the internal gear ring, and the left bearing supporting the left end of the planetary carrier is press-fitted on the outer shell end cover.

5. The hub drive structure with static through-shaft support according to claim 4, characterized in that: The outer shell end cap is integrally formed with the inner gear ring, and an output oil seal is press-fitted between the right end of the inner gear ring and the planetary carrier.

6. The hub drive structure with static through-shaft support according to claim 3, characterized in that: It also includes a hub support frame located on the right side of the outer casing end cover. The planetary carrier is set in the internal gear ring, and the internal gear ring is set in the hub support frame. The right end of the planetary carrier extends out of the internal gear ring. The right end of the hub support frame is splined and fitted onto the right end of the planetary carrier. The left end is supported on the internal gear ring by the left bearing. The hub is assembled on the hub support frame.

7. The hub drive structure with static through-shaft support according to claim 6, characterized in that: The hub support frame includes a left support ring and a right support ring fixed to the right end of the left support ring by bolts. An annular cavity for accommodating the internal gear ring is formed between the left and right support rings. The second left bearing is press-fitted onto the internal gear ring, the second left support ring is press-fitted onto the second left bearing, and the right support ring is splinedly fitted onto the right end of the planetary carrier.

8. The hub drive structure with static through-shaft support according to claim 7, characterized in that: A support bearing is press-fitted between the planetary carrier and the internal gear ring, and an output oil seal is press-fitted onto the left support ring to seal the space between the left support ring and the outer casing end cover.

9. The hub drive structure with static through-shaft support according to claim 3, characterized in that: The internal gear ring is set in the planet carrier, and a left bearing is press-fitted between the left end of the internal gear ring and the left end of the planet carrier. An output oil seal is press-fitted on the left end of the planet carrier to seal the planet carrier and the outer casing end cover.

10. A driving method for a two-wheeled electric vehicle, characterized in that: A hub drive structure with static through-shaft support as described in any one of claims 1 to 9 is installed on the rear wheel hub of a two-wheeled electric vehicle. When the motor is started, the power of the motor is transmitted to the planet carrier via the sun gear and planet gears. The inner planet carrier drives the hub to rotate, thereby achieving drive.

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