TWM604297U - Inner rotor hub motor system and power assisted bicycle - Google Patents

Abstract

Provided is an inner rotor hub motor system, including a hub that includes a hub cover and a housing and has therein a motor assembly and a reduction drive, and a main shaft disposed through and extending out of the hub. An input assembly connected to and driving the hub is provided on one end of the main shaft. The motor assembly includes first and second end covers, and an inner rotor rotatably coupled to the main shaft and to the hub via the reduction drive. The first end cover around the main shaft is rotatably connected to the hub cover. The correspondingly-shaped opposing surfaces of the first end cover and the hub cover are separated by a distance. The lifetime of the hub motor is elongated by cooling the motor with the hub cover having fins on its outer surface for increasing air contact area and improving cooling performance.

Description

Inner rotor hub motor transmission system and assisted bicycle

This creation is about power-assisted bicycles, especially an inner rotor hub motor transmission system.

With the development of the times and the advancement of technology, power-assisted bicycles have also developed vigorously. A power-assisted bicycle is a bicycle that is equipped with a power-assisted system to facilitate the riding of the user. Power-assisted bicycles can provide corresponding power support according to the pedaling strength of the rider, reduce the riding burden of the rider, greatly increase the riding comfort and riding mileage, and are gradually welcomed by the market.

The existing power-assisted bicycle retains the original bicycle frame body, thus limiting the volume of the hub motor, resulting in serious heat generation under working conditions, and affecting the service life of the motor. At the same time, the existing power-assisted bicycles are mainly geared mechanically, and there is a sense of frustration when shifting gears, and improper operation may cause problems such as chain disconnection, which affects the riding experience.

In order to overcome the shortcomings of the prior art, the purpose of this creation is to provide an inner rotor hub motor transmission system with good heat dissipation effect and capable of continuously variable transmission.

This creation provides an inner rotor hub motor transmission system, which includes a hub and a main shaft, the hub includes a hub cover and a shell, and the hub is provided with a motor assembly and a reduction mechanism. One end of the main shaft is provided with an input assembly connected with the hub and driving the hub. The motor assembly includes a first end cover, a second end cover and an inner rotor that is rotatably connected to the main shaft. The inner rotor is connected to the hub via a reduction mechanism and drives the hub. The first end cover is sleeved on the main shaft and is rotatably connected with the hub cover. The shape of the outer surface of the first end cover is adapted to the shape of the inner surface of the hub cover and is separated by a predetermined distance.

In one embodiment, a thermal grease is filled between the hub cover and the first end cover, and the outer surface of the hub cover is provided with heat dissipation fins.

In an embodiment, the motor assembly further includes a stator. The stator is fixed between the first end cover and the second end cover. The stator is separated from the inner wall of the hub by a predetermined distance. The inner wall of the shell of the wheel hub is provided with an oil separation sleeve.

In an embodiment, the speed reduction mechanism includes a harmonic drive speed reducer. The harmonic drive reducer includes a wave generator, flexible gears, flexible bearings, and rigid gears. The inner rotor is connected to the wave generator and drives the wave generator. The wave generator is connected to the main shaft in a rotatable manner. The input component is connected with the flexible gear and drives the flexible gear. The rigid gear is installed and fixed on the inner wall of the hub shell.

In one embodiment, the inner rotor hub motor transmission system further includes an external controller. The controller is used to control the start-stop and speed of the motor components.

In one embodiment, the controller is used to control the motor assembly so that the ratio of the rotation speed of the motor assembly to the pedaling speed input by the input assembly is maintained at a preset value.

In one embodiment, the input assembly includes a ring gear base rotatably connected to the main shaft, and a torsion sleeve connected to and driven by the ring gear base. The upper part of the torsion sleeve is rotatably connected with the ring gear base, the middle part of the torsion sleeve is rotatably connected with the main shaft, and the flexible gear is installed and connected to the bottom of the torsion sleeve.

In an embodiment, a first bearing is provided between the torsion sleeve and the hub, a second bearing is provided between the torsion sleeve and the main shaft, and a third bearing is provided between the ring gear base and the main shaft.

In one embodiment, a pawl is provided on the gear plate tower base, and the inner wall of the torsion sleeve is provided with a ratchet wheel adapted to the pawl.

In one embodiment, the inner rotor hub motor transmission system further includes a clutch arranged on the hub, and the clutch is adapted to the torque sleeve.

In the inner rotor hub motor transmission system provided by the embodiment of the invention, the stator is fixedly connected between the first end cover and the second end cover. The shape of the outer surface of the first end cover is matched with the shape of the inner surface of the hub cover and is separated by a predetermined distance, and thermal grease is filled between the two. During operation, the inner rotor and the hub rotate, and the motor dissipates heat through the hub cover. In addition, heat dissipation fins are arranged on the outer surface of the hub cover, which increases the contact area between the hub cover and the air, improves the heat dissipation effect of the hub motor, and prolongs the service life of the hub motor.

The creation will be further described in detail below in conjunction with the embodiments and the accompanying drawings.

Hereinafter, an in-wheel motor drive system and a power-assisted bicycle will be described with reference to FIGS. 1 to 2. The assisted bicycle 9 includes a frame 10 and an inner rotor hub motor drive system. 1 and 2, the inner rotor hub motor transmission system includes a hub 1 and a main shaft 2. The hub 1 includes a hub cover 1a and a housing 1b. The two ends of the main shaft 2 respectively extend out of the hub 1. One end of the main shaft 2 (the end of the main shaft 2 on the right in FIG. 1) is installed and connected with an input assembly 3, and the input assembly 3 and The hub 1 is connected to and drives the hub 1. The hub 1 is provided with a motor assembly 4 and a speed reduction mechanism. The motor assembly 4 includes a first end cover 4c, a second end cover 4d, a stator, and an inner rotor 4b connected to the main shaft 2 in a rotatable manner relative to the main shaft 2. The inner rotor 4b is connected to the hub 1 and drives the hub 1 via a speed reduction mechanism described in detail later. The first end cover 4c is sleeved on the main shaft 2 and is rotatably connected with the hub cover 1a via the first bearing 12. The shape of the outer surface of the first end cover 4c matches the shape of the inner surface of the hub cover 1a and is separated by a predetermined distance.

Specifically, the basic structure and principle of the motor assembly 4 are the same as the existing motor. The motor assembly 4 further includes a magnet 4f, and the stator 4a of the motor assembly 4 is provided with a winding 4e. The thermal grease 6 is filled between the hub cover 1a and the first end cover 4c, and the outer surface of the hub cover 1a is provided with heat dissipation fins 1c. The stator 4a is fixed between the first end cover 4c and the second end cover 4d, and the stator 4a is separated from the inner wall of the hub 1 by a predetermined distance. The inner wall of the shell 1b near one end of the hub cover 1a is provided with a grease trap 8.

The in-wheel motor in the embodiment of this case is an in-wheel motor using an inner rotor structure, and its stator 4a is fixedly installed between the first end cover 4c and the second end cover 4d. The shape of the outer surface of the first end cover 4c matches the shape of the inner surface of the hub cover 1a and is separated by a predetermined distance, and the thermal grease 6 is filled between the two. In the working process, when the inner rotor 4b and the hub 1 rotate, the heat generated by the winding 4e of the motor is dissipated through the heat-conducting grease 6 through the hub cover 1a. Furthermore, heat dissipation fins 1c are provided on the outer surface of the hub cover 1a. The heat dissipation fin 1c is a fin-shaped protrusion integrally provided on the surface of the hub cover 1a to increase the contact area between the hub cover 1a and the air, improve the heat dissipation effect of the hub motor, and prolong the service life of the hub motor.

In this embodiment, the reduction mechanism includes a harmonic drive reducer 5, which includes a wave generator 5a, a flexible gear 5b, a flexible bearing 5c, and a rigid gear 5d. The inner rotor 4b is connected to the wave generator 5a and drives the wave generator 5a, and the wave generator 5a is connected to the main shaft 2 in a rotatable manner. Specifically, the wave generator 5a and the inner rotor 4b are rotatably connected with the main shaft 2 via the second bearing 13 respectively. The input assembly 3 is connected with the flexible gear 5b and drives the flexible gear 5b. The rigid gear 5d is mounted and fixed on the inner wall of the housing 1b of the hub 1.

Specifically, a flexible bearing 5c is provided between the flexible gear 5b and the wave generator 5a. The basic structure and working principle of the flexible gear 5b, flexible bearing 5c and rigid gear 5d of the harmonic drive reducer 5 are the same as those of the existing harmonic reducer. The motor assembly 4 further includes a controller, which has a preset program that can be used to control the start, stop and speed of the motor.

The in-wheel motor transmission system in this creative embodiment has two driving modes: a pedaling driving mode and a hybrid driving mode (that is, a hybrid driving of motor output and human pedaling). In the working process of the hybrid drive mode of the hub motor transmission system, the motor assembly 4 is activated to drive the wave generator 5a to rotate, and the flexible gear 5b and the rigid gear 5d are driven to rotate relative to each other through the flexible bearing 5c. At the same time, the pedaling input The component 3 drives the flexible gear 5b to rotate, and the two input speeds are added and mixed to drive the rigid gear 5d to rotate and drive the hub 1 to rotate. The controller adjusts the motor speed according to the pedaling input value of the rider, and sets the motor speed corresponding to different pedaling speeds by the preset program, and controls the speed of the motor and the flexible bearing 5c and the flexible gear 5b to reach the preset ratio of variable speed, that is, control the speed The dynamic gear ratio between (wheel hub 1 speed) and pedal input value, so as to achieve the purpose of continuously variable speed. The user can select the required gear ratio or vehicle speed through a preset program during the riding process, without the need to shift gears, simplifying the operation. In addition, the in-wheel motor drive system of this creation is equipped with a harmonic drive reducer 5, which is more streamlined compared with the structure using an external transmission, reduced in size and lighter in weight. It achieves the purpose of continuously variable transmission through program control of the gear ratio, improves the riding experience, and makes the riding process more comfortable and intelligent.

Figure 3 is a graph showing the ratio of pedaling speed to vehicle speed for different gear shifting modes. In Figure 3, the X axis is the rotation speed of the pedaling input component, and the Y axis is the vehicle speed. In Fig. 3, curve a is the intelligent gear ratio curve of the in-wheel motor transmission system created, curve b is the gear ratio curve without variable speed (ie single speed), and curve c is the gear ratio curve of traditional mechanical transmission. As shown in Figure 3, the gear ratio value in the a curve increases smoothly without jitter. Therefore, the transmission process of the transmission system is smoothly transitioned, so there is no frustration during the riding process, and the riding process is more comfortable.

Among them, the transmission ratio of the harmonic drive reducer 5 is 1/50. The speed of hub 1 is equal to the motor speed multiplied by the transmission ratio plus the pedal input value. In addition, FIG. 4 shows the change in the ratio of the rotation speed of the hub to the pedal input rotation speed of the creative embodiment. Referring to FIG. 4, the rider can adjust the gear ratio within the range of about 1 to about 3 in the ratio of pedal input speed to wheel hub output speed. In other embodiments, the harmonic drive reducer 5 can also be designed according to production requirements to adjust the transmission ratio and adjust the range of the transmission ratio. In other embodiments, a traditional planetary gear train deceleration mechanism can also be used.

1, in this embodiment, the input assembly 3 includes a ring gear base 3 a rotatably connected to the main shaft 2, and a torsion sleeve 3 b connected to and driven by the ring gear base 3 a. The structure and basic principles of the chainring base 3a are the same as those of the existing chainring base. The upper part of the torsion sleeve 3b is rotatably connected with the ring gear base 3a, the middle of the torsion sleeve 3b is rotatably connected with the main shaft 2, and the flexible gear 5b is installed to be connected to the bottom of the torque sleeve 3b. A third bearing 14 is provided between the torsion sleeve 3 b and the hub 1, a fourth bearing 15 is provided between the torsion sleeve 3 b and the main shaft 2, and a fifth bearing 16 is provided between the ring gear base 3 a and the main shaft 2.

Specifically, a clutch 7 is provided in the hub 1, and the clutch 7 is adapted to the torque sleeve 3b. When the pedaling drive mode is selected, the pedaling force drives the torsion sleeve 3b to rotate through the ring gear base 3a, and then the torsion sleeve 3b drives the wheel hub 1 to rotate through the clutch 7.

In this embodiment, referring to Figs. 1 and 2, a pawl 3d is provided on the ring gear base 3a, and the inner wall of the torsion sleeve 3b is provided with a ratchet wheel 3c that matches the pawl 3d, so that the assisted bicycle 9 Do not drag the bicycle pedal to rotate when sliding.

In addition, 3 to 11 shifting chainrings 11 can be provided on the ring gear base 3a, so the user can select the pedaling speed and vehicle speed in a wider range.

The above is an explanation of the in-wheel motor drive system and assisted bicycle of this creation, which is used to help understand this creation, but the implementation of creation is not limited by the above-mentioned embodiments, and any changes made without departing from the principle of this creation, Modifications, substitutions, combinations, and simplifications should all be equivalent replacement methods, and they are all included in the protection scope of this creation.

1: Wheel hub 1a: Hub cover 1b: shell 1c: cooling fins 2: Spindle 3: input component 3a: Sprocket body 3b: Torque sleeve 3c: ratchet 3d: pawl 4: Motor components 4a: stator 4b: inner rotor 4c: first end cap 4d: second end cap 4e: winding 4f: Magnet 5: Harmonic drive reducer 5a: Wave generator 5b: Flexible gear 5c: Flexible bearing 5d: rigid gear 6: Thermal grease 7: Clutch 8: Oil trap 9: Power-assisted bicycle 10: Frame 11: Variable speed chainring 12: The first bearing 13: The second bearing 14: The third bearing 15: The fourth bearing 16: Fifth bearing

Figure 1 is a schematic structural diagram of the inner rotor hub motor transmission system of the creative embodiment;

Figure 2 is a schematic diagram of the structure of the assisted bicycle according to the creative embodiment;

Figure 3 is a graph of the ratio of pedaling speed to vehicle speed for different gear shifting modes;

Figure 4 shows the change in the ratio of the hub speed to the pedaling speed of the creative embodiment.

1: Wheel hub

1a: Hub cover

1b: shell

1c: cooling fins

2: Spindle

3: input component

3a: Sprocket body

3b: Torque sleeve

3c: ratchet

3d: pawl

4: Motor components

4a: stator

4b: inner rotor

4c: first end cap

4d: second end cap

4e: winding

4f: Magnet

5: Harmonic drive reducer

5a: Wave generator

5b: Flexible gear

5c: Flexible bearing

5d: rigid gear

6: Thermal grease

7: Clutch

8: Oil trap

12: The first bearing

13: The second bearing

14: The third bearing

15: The fourth bearing

16: Fifth bearing

Claims (10)

An inner rotor hub motor transmission system, including: A hub, the hub includes a hub cover and a shell, the hub is provided with a motor assembly and a reduction mechanism; and A main shaft, one end of the main shaft is provided with an input assembly, the input assembly is connected with the hub and drives the hub, The motor assembly includes a first end cover, a second end cover, and an inner rotor rotatably connected to the main shaft. The inner rotor is connected to the hub via the reduction mechanism and drives the hub, and the first end cover is sleeved It is arranged on the main shaft and is rotatably connected with the hub cover. The outer surface shape of the first end cover matches the inner surface shape of the hub cover and is spaced apart by a predetermined distance. For example, the inner rotor hub motor transmission system of claim 1, wherein a thermal grease is filled between the hub cover and the first end cover, and the outer surface of the hub cover is provided with heat dissipation fins. For example, the rotor hub motor transmission system in claim 1, wherein the motor assembly further includes a stator, the stator is fixed between the first end cover and the second end cover, and the stator and the inner wall of the hub are spaced apart Distance, the inner wall of the shell is provided with an oil trap. For example, the inner rotor hub motor transmission system in claim 1, wherein the reduction mechanism includes a harmonic drive reducer, the harmonic drive reducer includes a wave generator, a flexible gear, a flexible bearing, and a rigid gear, the inner rotor and the wave The generator is connected to and drives the wave generator, and the wave generator is rotatably connected to the main shaft. The input component is connected to the flexible gear and drives the flexible gear. The rigid gear is mounted and fixed to the hub of the hub. The inner wall of the housing. For example, the internal rotor hub motor transmission system in claim 4 further includes an external controller, which is used to control the start-stop and speed of the motor assembly. For example, in the rotor hub motor transmission system in claim 5, the controller is used to control the motor assembly so that the ratio of the rotation speed of the motor assembly to the pedaling speed input by the input assembly is maintained at a preset value. For example, the rotor hub motor transmission system in claim 1, wherein the input assembly includes a ring gear base rotatably connected to the main shaft, and a torsion sleeve connected to and driven by the ring gear base, the The upper part of the torsion sleeve is rotatably connected with the ring gear base, the middle part of the torsion sleeve is rotatably connected with the main shaft, and the flexible gear is installed and connected to the bottom of the torsion sleeve. For example, the inner rotor hub motor transmission system of claim 7, wherein a first bearing is provided between the torsion sleeve and the hub, a second bearing is provided between the torsion sleeve and the main shaft, and the ring gear base and A third bearing is arranged between the main shafts. For example, the rotor hub motor transmission system in claim 7 further includes a clutch provided on the hub, and the clutch is matched with the torque sleeve. A power-assisted bicycle, including: A frame; and The inner rotor hub motor drive system according to any one of claims 1 to 9.

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