TWM666882U - Electric bicycle booster of inner-rotor-type wheel hub motor with harmonic drive - Google Patents

Abstract

An electric bicycle power assist device with an inner rotor hub motor having a harmonic transmission deceleration mechanism includes a hub motor, a harmonic gear deceleration mechanism, a hub right fixed shaft, a hub left fixed shaft, and a hub housing, wherein the hub motor includes a stator, a rotor, and a hub rotating shaft with an elliptical camshaft, and the harmonic gear deceleration mechanism includes a fixed The rigid gear ring and the integrated planetary gear have flexible gears and rigid rims. The camshaft of the hub shaft inputs the rotational motion, and the difference in the number of teeth between the flexible gear and the rigid gear ring drives the flexible gear to rotate in the reverse direction at a reduced speed. At the same time, the rigid rim locked inside the hub shell drives the hub shell and the rim to rotate at a reduced speed.

Description

Electric bicycle power assist device with inner rotor wheel motor having harmonic transmission reduction mechanism

This invention is about an electric bicycle power-assist device with an inner rotor wheel hub motor having a harmonic transmission deceleration mechanism, and in particular, it refers to a technology of an electric bicycle inner rotor wheel hub motor power-assist transmission mechanism that can achieve miniaturization, improve the power-assist effect, and does not require a pin-joint centering mechanism.

Due to environmental protection and the impact of the previous epidemic, major cities around the world encourage citizens to use bicycles as a means of transportation. When the distance between commuting or leisure destinations is long or there are uphill sections on the road, electric bicycles with motor-assisted devices are more in line with the needs of riders.

The common electric bicycle power-assist devices on the market use wheel hub motors (wheel hub motors), which can be divided into outer rotor wheel hub motors and inner rotor wheel hub motors, and can be divided into gearless wheel hub motors and geared wheel hub motors according to whether the motor passes through a gear reduction mechanism. The gear reduction mechanism in the commonly used geared outer rotor wheel hub motors on the market actually uses a simple centering gear system, including a sun gear (input gear), three middle idler gears and a ring gear (output gear), so its reduction ratio is not high. For example, the reduction ratio of a sun gear with 21 teeth and a ring gear with 93 teeth is only -4.4. The new patent No. M484555 "Bicycle power-assisted motor with one-way function" adopts a compound gear system inner rotor hub motor, and the large-diameter teeth and small-diameter teeth pinned on the same shaft are engaged with the sun gear (input wheel) and the ring gear (output wheel) respectively. The reduction ratio of this compound gear system can be obtained by matching gears (such as the sun gear 20 teeth drive the large-diameter teeth 60 teeth, and the small-diameter teeth 20 teeth rotating with the large-diameter teeth drive the ring gear 93 teeth) to obtain a higher reduction ratio (about -14) than the simple centering gear system, but it also requires a large gear to match. It can be seen that the gear reduction mechanism of the wheel hub motor on the market has poor deceleration and torque enhancement effects, resulting in poor climbing performance on long and steep slopes.

Compared with the centering gear system with a sun gear (including simple and compound gear systems), the small-tooth-difference planetary gear reduction mechanism without a sun gear has a higher reduction ratio, so it can greatly improve the output torque effect of the wheel hub motor, and the number of teeth can be smaller, that is, smaller size and weight. The small-tooth-difference first-order planetary gear reduction mechanism without a sun gear includes a cycloidal pinwheel reducer, a harmonic reducer, and a first-order progressive open-cable small-tooth-difference planetary gear reduction mechanism. Therefore, the invention patent No. I773222 "Electric bicycle power-assisting device with inner rotor wheel hub motor having first-order progressive open-line small-tooth difference planetary gear reduction transmission mechanism" adopts inner rotor motor and first-order progressive open-line small-tooth difference planetary gear reduction mechanism; the invention patent No. I786567 "Electric bicycle power-assisting device with outer rotor wheel hub motor having first-order progressive open-line small-tooth difference planetary gear reduction transmission mechanism" adopts outer rotor motor and first-order progressive open-line small-tooth difference planetary gear reduction mechanism. Invention patent No. I694951 "Hydrodynamic gear drive in electric bicycle power-assist system" adopts an inner rotor motor and a hydrodynamic pinwheel reducer. Invention patent No. I694952 "Harmonic gear drive mechanism for electric power-assistance of electric bicycle" adopts an inner rotor motor and a harmonic reducer; new patent No. M606074 "Hub motor drive system and power-assisted bicycle" adopts an outer rotor motor and a new harmonic reducer with two degrees of freedom.

Although the manufacturing cost of harmonic reducer is higher, the advantage of harmonic reducer is that the input shaft of the planetary gear (output flexwheel) is driven by the camshaft as the concentric shaft, that is, the output shaft and the input shaft are on the same axis (center axis), unlike the first-order cycloidal pinwheel reducer and the first-order progressive gear reducer. The eccentric shaft (pin) drives the planetary gear in the open-line small-tooth difference planetary gear reduction mechanism. Therefore, the harmonic reducer does not need an additional constant-speed centering mechanism with a hole and pin joint to convert the rotational motion of the eccentric shaft into the rotational output motion of the center shaft, as the first-order cycloidal pinwheel reducer and the first-order progressive open-line small-tooth difference planetary gear reduction mechanism require. However, the housing 10 in the invention patent No. 1694952 "Electric bicycle electric power assist harmonic gear transmission mechanism" is not used to drive the electric bicycle wheel rim to rotate, but is used to lock the motor end cover and the steel wheel 30, and to fix the internal parts. The hollow shaft 70 is driven by the motor inner rotor 21, and the cam ring 80 and the flexible bearing 42 sleeved on the hollow shaft drive the output plate 50. However, the rotating output component is only the output plate on the right side. The invention does not explain how the output plate 50 and the end cap 51 are connected to the wheel frame through the spokes to drive the center wheel rim to rotate. In addition, the motor drives the hollow shaft 70 as the rotation center axis, but the invention does not specifically explain how the hub center fixed axis is connected to the front fork and rear fork of the frame, or how the housing 10 (fixing part) is installed and fixed to the front fork, rear fork or frame of the frame. As for the new patent No. M606074 "Hub motor transmission system and power-assisted bicycle", the three components of the harmonic transmission reducer (wave generator, flexible gear and rigid gear) will rotate, so it can be calculated that its degree of freedom is 2. Since the speed of the flexible gear driven by the pedal input assembly is not constant, the output speed of the rigid gear is also not constant, but fluctuates or speeds up and down. If the pedal input assembly is not used, since none of the three components are fixed (but constrained to the frame), the flexible gear connected to the pedal input assembly may also rotate, but it is impossible to keep a constant speed or not move, causing the output speed of the rigid gear to fluctuate. In addition, since the flexible gear is an elliptical gear and the rigid gear is a circular gear, the meshing between the two is a very special way. In practice, the pedal input component drives the flexible gear to rotate, which is very likely to interfere with the wave generator driving the flexible gear and the rigid gear to mesh. Furthermore, the two-degree-of-freedom harmonic transmission mechanism will greatly reduce the reduction ratio of the original one-degree-of-freedom harmonic transmission mechanism (those who are interested can derive the speed relationship between the three components from the planetary gear motion analysis list method or the planetary gear motion analysis formula method). Therefore, it is unwise to redesign the harmonic gear reduction mechanism into a two-degree-of-freedom mechanism.

The main purpose of this invention is to provide an electric bicycle power assist device with an inner rotor wheel motor having a harmonic transmission deceleration mechanism that is different from the structural and technical features of the invention patent No. I694952 and the new patent No. M606074 to solve the aforementioned problems (see [0005]).

The technical means for achieving the purpose of this invention include a wheel hub motor, a harmonic gear reduction mechanism, a wheel hub right side fixed axle, a wheel hub left side fixed axle and a wheel hub outer shell, and are assembled by supporting and connecting accessories to form an electric bicycle power-assisting device with an inner rotor wheel hub motor having the effect of this invention, wherein the wheel hub outer shell includes a shell body, a shell right side cover and a shell left side cover, and a part of the wheel hub right side fixed axle and the wheel hub left side fixed axle are installed on the wheel hub. The inner part of the wheel hub shell is partially outside the wheel hub shell and can be locked to the front fork or rear fork of the frame by nuts. The right side fixed axle of the wheel hub contains a chamber inside the wheel hub shell as a stator bracket. The wheel hub motor contains a stator, a rotor installed inside the stator, and a wheel hub shaft. The wheel hub shaft contains an elliptical camshaft, which is connected to the rotor by a flat key and two C-shaped retaining rings and rotates together. The stator is rotated by It is fixed to the inside of the stator bracket on the right side of the hub by a C-shaped retaining ring and a strong magnetic attraction between the rotor and the rotor. The harmonic gear reduction mechanism includes a rigid gear ring, a planetary gear with a flexible gear and a rigid ring edge, and a flexible bearing (or flexible bushing) interference fit on the inner diameter of the flexible gear. The rigid gear ring is screwed to the end face of the stator bracket on the right side of the hub. The speed reduction and force increase movement sequence is that the camshaft of the hub shaft is used as the input rotation The flexible gear of the integrated planetary wheel rotates, driving the flexible gear of the integrated planetary wheel to engage with the rigid gear ring, and the flexible gear of the integrated planetary wheel is driven to rotate in the reverse direction at a reduced speed by the difference in the number of teeth engaged between the flexible gear of the integrated planetary wheel and the rigid gear ring. At the same time, the rigid ring edge of the integrated planetary wheel locked in the shell body drives the hub shell to rotate at a reduced speed. Since the hub shell is connected to the rim by spokes, the hub shell finally drives the rim to rotate at a reduced speed. The rotor and the wheel hub shaft rotate on the right and left fixed axles of the wheel hub through the support of two bearings. Similarly, the wheel hub housing also rotates on the right and left fixed axles of the wheel hub through the support of two bearings.

11: Rigid gear ring

12: Integrated planetary gear

13: Flexible gear

14: Rigid environment

15: Flexible bearing

21: Rotor

22: Stator

23: Wheel hub shaft

24: Camshaft

25: Flat key

26: C-shaped buckle 1

27: C-shaped buckle 2

28: Right second ball bearing

29: Second left ball bearing

31: Shell body

32: Right side cover of the case

33: Left side cover of the case

34: Screw 2

35: Right ball bearing

36: Left ball bearing

37: Right side seal

38:Left side seal

39: Screw three

41: Wheel hub right side fixed axle

42: Left side fixed axle of wheel hub

43: Stator bracket

44: C-shaped buckle ring three

45: Screw 1

Figure 1 is a cross-sectional view of an electric bicycle power assist device having an inner rotor wheel hub motor with a harmonic transmission deceleration mechanism according to an embodiment of the present invention.

Figure 2 is a combination diagram of an electric bicycle power assist device with an inner rotor wheel hub motor having a harmonic transmission deceleration mechanism according to an embodiment of the present invention.

In order to help the review committee to further understand the technical features of the electric bicycle power-assisting device with an inner rotor wheel hub motor with a harmonic transmission deceleration mechanism, a specific embodiment is described in detail with diagrams as follows:

Please refer to Figures 1 and 2 for the embodiment of the electric bicycle power-assisting device with inner rotor wheel motor and harmonic transmission deceleration mechanism of the present invention. The embodiment includes a wheel motor, a harmonic gear deceleration mechanism, a wheel right fixed shaft 41, a wheel left fixed shaft 42 and a wheel housing, and is assembled by supporting and connecting accessories to form an electric bicycle power-assisting device with inner rotor wheel motor and harmonic transmission deceleration mechanism having the effect of the present invention.

The wheel hub shell includes a shell body 31, a right shell cover 32 and a left shell cover 33. The right shell cover 32 and the left shell cover 33 are fixed to the shell body 31 by screws 34. The wheel hub shell is connected to the wheel rim (not shown) by spokes (not shown) and drives the wheel rim to rotate.

Part of the right wheel hub fixed axle 41 and the left wheel hub fixed axle 42 is installed inside the wheel hub shell, and part of it is outside the wheel hub shell and can be locked on the front fork (not shown) or rear fork (not shown) of the frame by nuts. The right wheel hub fixed axle 41 includes a chamber inside the wheel hub shell as a stator bracket 43.

The wheel hub motor includes a stator 22, a rotor 21 installed inside the stator 22, and a wheel hub rotating shaft 23. The wheel hub rotating shaft 23 includes an elliptical camshaft 24, and is connected to the rotor 21 through a flat key 25, a C-type buckle ring 1 26, and a C-type buckle ring 27. The wheel hub rotating shaft 23 rotates on the right side fixed shaft 41 and the left side fixed shaft 42 of the wheel hub through the support of the right second ball bearing 28 and the left second ball bearing 29. The stator 22 is fixed inside the stator bracket 43 of the right side fixed shaft 41 of the wheel hub through the C-type buckle ring 3 44 and the strong magnetic attraction between it and the rotor 21.

The harmonic gear reduction mechanism includes a rigid gear ring 11, an integrated planetary wheel 12 having a flexible gear 13 and a rigid annular rim 14, and a flexible bearing 15 interference-fitted to the inner diameter of the flexible gear 13, wherein the rigid gear ring 11 is fixed to the end face of the stator bracket 43 of the fixed shaft 41 on the right side of the wheel hub by screw 1 45, and the rigid annular rim 14 of the integrated planetary wheel 12 is fixed to the housing body 31 by screw 3 39.

The deceleration and force-enhancing motion sequence of the electric bicycle power-assisting device with an inner rotor hub motor having a harmonic transmission deceleration mechanism of the present invention is that the camshaft 24 of the hub rotating shaft 23 is input for rotational motion, driving the flexible gear 13 of the integrated planetary gear 12 to engage with the rigid gear ring 11, and the integrated planetary gear 12 is driven by the difference in the number of teeth engaged between the flexible gear 13 and the rigid gear ring 11. 2 makes a decelerated rotation in the opposite direction to the input rotation, and at the same time, the rigid annular edge 14 of the integrated planetary gear 12 locked in the housing body 31 drives the hub housing to make a decelerated output rotation, that is, the hub housing drives the wheel rim (not shown) to make a decelerated output rotation on the right side fixed shaft 41 and the left side fixed shaft 42 of the hub through the support of the right first ball bearing 35 and the left first ball bearing 36.

In summary, this invention provides an electric bicycle power assist device with an inner rotor wheel motor having a harmonic transmission deceleration mechanism, and an application for a new patent is submitted in accordance with the law.

11: Rigid gear ring

12: Integrated planetary gear

13: Flexible gear

14: Rigid environment

15: Flexible bearing

21: Rotor

22: Stator

23: Wheel hub shaft

24: Camshaft

25: Flat key

26: C-shaped buckle 1

27: C-shaped buckle 2

28: Right second ball bearing

29: Second left ball bearing

31: Shell body

32: Right side cover of the case

33: Left side cover of the case

34: Screw 2

35: Right ball bearing

36: Left ball bearing

37: Right side seal

38:Left side seal

39: Screw three

41: Wheel hub right side fixed axle

42: Left side fixed axle of wheel hub

43: Stator bracket

44: C-shaped buckle ring three

45: Screw 1

Claims (1)

An electric bicycle power assist device with an inner rotor wheel motor having a harmonic transmission deceleration mechanism, comprising: The wheel hub shell includes a shell body, a right shell cover and a left shell cover. The right shell cover and the left shell cover are fixed to the shell body by screws. The wheel hub shell can be connected to and drive the wheel rim to rotate; The right side fixed axle of the wheel hub and the left side fixed axle of the wheel hub are partially installed inside the wheel hub shell, and partially installed outside the wheel hub shell and can be locked to the front fork or rear fork of the frame by nuts. The right side fixed axle of the wheel hub contains a chamber inside the wheel hub shell as a stator bracket; The wheel hub motor includes a stator, a rotor installed inside the stator, and a wheel hub rotating shaft. The wheel hub rotating shaft is connected to the rotor through a flat key and two C-shaped retaining rings, and then rotates on the right side fixed shaft of the wheel hub and the left side fixed shaft of the wheel hub through the support of two ball bearings. The stator is fixed inside the stator bracket of the right side fixed shaft of the wheel hub through a C-shaped retaining ring and a strong magnetic attraction between the rotor and the stator; The harmonic gear reduction mechanism includes a rigid gear ring, an integrated planetary gear with a flexible gear and a rigid ring edge, and a flexible bearing interference-assembled on the inner diameter of the right-side flexible gear; Its characteristics are: The hub shaft has an elliptical camshaft, the rigid gear ring is locked to the stator bracket end face of the fixed shaft on the right side of the hub, and the rigid ring of the integrated planetary wheel is locked in the main body of the housing. The camshaft of the hub shaft inputs the rotational motion, driving the flexible gear of the integrated planetary wheel to engage with the rigid gear ring. , and the tooth number difference between the flexible gear and the rigid gear ring of the integrated planetary wheel drives the flexible gear of the integrated planetary wheel to perform a deceleration rotation in the opposite direction of the input rotation. At the same time, the rigid ring edge of the integrated planetary wheel locked in the main body of the housing drives the outer shell of the wheel hub to perform an output rotation to achieve the effect of deceleration and force increase.

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