TWI822580B - Downsizing electric bicycle booster - Google Patents

Abstract

A miniature electric bicycle power-assisting device, including a harmonic deceleration mechanism, a linear actuator, a left fixed shaft, a right fixed shaft and a hub shell, and is assembled by supporting and connecting accessories, in which the linear actuator is installed in the harmonic deceleration The internal hollow space of the mechanism is locked to the left fixed axis and the right fixed axis. The linear actuator has a plurality of radial actuating rods along the circumferential direction and uses two radial end actuating rods to drive the harmonic deceleration. institution. Compared with the electric bicycle power-assist device technology on the market or other announced patents, which uses an inner-rotor or outer-rotor hub motor to drive a gear reduction mechanism, it clearly has the effect of reducing the axial size.

Description

Downsizing e-bike power assist

The present invention relates to a miniaturized power-assisting device for electric bicycles, and in particular, to a technology of an electric bicycle power-assisting device that can achieve smaller size, lighter weight and improve the power-assisting effect.

Due to environmental protection and the impact of previous epidemics, major cities around the world encourage citizens to use bicycles as transportation. When commuting or leisure destinations are far away or there are uphill sections on the road, electric bicycles with motor assist devices More in line with needs.

Currently, the commonly used power-assisting devices for electric bicycles on the market use hub motors (hub motors), which can be divided into outer-rotor hub motors and inner-rotor hub motors. They can also be divided into gearless hub motors and inner-rotor hub motors according to whether there is a gear reduction mechanism in the motor. There are gear hub motors. The gear reduction mechanism in commonly used toothed external rotor hub motors on the market actually uses a simple centering gear system, including a sun gear (input wheel), three intermediate idler gears and ring teeth (output wheel), so its The 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. New Patent No. M484555 "Bicycle power-assist motor with one-way function" uses a compound gear train inner rotor hub motor. The large-diameter gear part and the small-diameter gear part are pinned to the same shaft and are connected to the sun gear (input wheel) and gear respectively. circle (lose The reduction ratio of this compound gear system is through the matching teeth (for example, the 20 teeth of the sun gear drive the 60 teeth of the large-diameter gear, and the 20 teeth of the small-diameter gear that rotates together with the large-diameter gear drive the 93 teeth of the ring gear) A higher reduction ratio (approximately -14) can be obtained than a simple center gear train, but it also requires a large gear fit. It can be seen that the gear reduction mechanism of the hub motor on the market has poor deceleration and torque improvement effects, making it difficult to climb long and steep slopes.

The planetary gear reduction mechanism without sun gear and small tooth difference has a higher reduction ratio than the center gear train with sun gear (including simple and compound gear trains), so it can greatly improve the output torque effect of the hub motor. Moreover, the number of teeth can be smaller, which means smaller volume and weight. The first-order planetary gear reduction mechanism with small tooth difference without sun gear includes cycloidal pinwheel reducer, harmonic reducer, and first-order involute small tooth difference planetary gear reduction mechanism. Therefore, the invention patent No. I694951 "Cycloidal gear transmission in electric bicycle power assist system" adopts an inner rotor motor and a cycloidal pinwheel reducer; the invention patent No. I694952 "Harmonic gear transmission mechanism for electric power assistance of electric bicycles" adopts Inner-rotor motor and harmonic reducer; Invention Patent No. I773222 "Electric bicycle power-assisting device with inner-rotor hub motor with first-order involute small-tooth-difference planetary gear reduction transmission mechanism" uses an inner-rotor motor and a first-order involute Open-line small-tooth-difference planetary gear reduction mechanism; Invention Patent No. I786567 "Electric bicycle power-assisting device with first-order involute small-tooth-difference planetary gear reduction transmission mechanism and external rotor hub motor" uses an external rotor motor and a first-order Involute small tooth difference planetary gear reduction mechanism.

Although the manufacturing cost of the harmonic reducer is relatively high, as far as the first-order small-tooth-difference planetary gear reduction mechanism is concerned, the advantage of the harmonic reducer is that the input shaft that drives the planetary gear (output flexspline) uses the camshaft as the centering axis. , that is, both the output shaft and the input shaft are the same One axis, unlike the first-order cycloidal pinwheel reducer and the first-order involute small-tooth-difference planetary gear reduction mechanism, the planetary gear is driven by the eccentric shaft (pin), so the harmonic reducer does not need to be like the first-order cycloidal pinwheel. The reducer and the first-order involute small-tooth-difference planetary gear reduction mechanism require an additional hole-pin jointed constant-velocity centering mechanism to convert the rotational motion of the eccentric shaft into the rotational output motion of the spindle. This is why the harmonic reducer The reason why it is currently widely adopted by the industry.

The casing 10 in the invention patent No. I694952 "Harmonic gear transmission mechanism for electric power assist of electric bicycles" is not used to drive the rim of the electric bicycle to rotate, but to lock the motor end side cover and the rigid wheel 30, and For fixing internal parts, the hollow shaft 70 is driven by the inner rotor 21 of the motor, and drives the output disk 50 through the cam ring 80 and the flexible bearing 42 set on the hollow shaft. However, the only components for rotating output are the output disk 50 on the right and The invention content does not explain how the combination of the output disk 50 and the end cover 51 on one side drives the center wheel to rotate through the spokes connecting the wheel frame. In addition, the motor drives the hollow shaft 70 as a Rotate the central axis, but the content of the invention does not include the center axis of the hub connected to the front fork and rear fork of the frame, or specifically explains how its housing 10 (fixing member) is installed and fixedly connected to the front fork and rear fork of the frame. where is the fork or frame. In addition, this invention patent and the other three invention patents mentioned above all use an inner rotor or outer rotor hub motor to drive the gear reducer. The electric bicycle power-assist device still has the disadvantage of being too large (please refer to the cross-sectional view of the motor or the gear reducer in each invention patent). The hub motor configuration will be known).

The present invention is mainly aimed at the above-mentioned shortcomings of the invention patent No. I694952 "Harmonic gear transmission mechanism for electric power assist of electric bicycles" and the existing problems of the electric bicycle power assist device using an inner rotor hub motor to drive the harmonic gear reduction mechanism. A brand new invention caused by the disadvantage of excessive size.

The main purpose of the present invention is to provide a reduced electric bicycle power assist device, which mainly replaces the inner rotor hub motor with a linear actuator to drive the harmonic gear reduction mechanism. Since the power assist device does not require a hub motor in the axial configuration , so the axial size can be reduced, achieving miniaturization and lightweight while still maintaining the boosting effect.

The technical means to achieve the object of the present invention include a harmonic gear reduction mechanism, a linear actuator, a left fixed shaft, a right fixed shaft and a hub shell, and are assembled by supporting and connecting accessories to form a reduced electric bicycle with the effects of the present invention. Power-assisting device, in which the harmonic gear reduction mechanism includes a rigid ring gear fixed on the left fixed shaft, an integrated planetary gear train with a left flexible gear and a right rigid ring cup, and a flexible bearing interference assembled on the left flexible gear of the integrated planetary gear The linear actuator has a plurality of radial actuator rods, and the hub shell includes a shell main body, a right side cover and a left side cover. The linear actuator is placed in the hollow space inside the harmonic gear reduction mechanism to support and drive the movement of the integrated planetary gear. The linear actuator is locked on the left fixed axis and the right fixed axis to replace the wheel hub motor and wheel hub. shaft, so there is no need for an extra axial and radial space to install the traditional hub motor and hub shaft. For the above actions, please refer to Figure 1, which is a schematic diagram of a linear actuator driving an integrated planet gear with two radial end actuating rods sequentially along the circumferential direction. The plurality of radial actuating rods of the linear actuator 21 include two actuated rods. When the two adjacent radial ends of the two unactuated execution rods 23 start to contact the flexible bearing 15 (or flexible bushing) inside the left flexible gear 13, the first two The actuated execution rod 22 returns to the non-driven position, and starts to drive the left flexible gear 13 again and again. At the same time, the difference in the number of teeth between the left flexible gear 13 and the rigid ring gear 11 is used. Achieve deceleration movement.

11: Rigid ring gear

12: Integrated planetary wheel

13:Left flexible gear

14: Right rigid ring cup

15:Flexible bearings

21: Linear actuator

22: The execution rod has been actuated

23: The execution rod is not actuated

31: Shell body

32: Cover on the right side of the shell

33: Cover on the left side of the shell

34:Screw

35: Right ball bearing

36: Left side ball bearing

37:Right seal

38:Left seal

39:Screw

41: Right fixed axis

4 May 1: Fixed axis ladder on the right side

42: Left fixed axis

421: Left fixed axis ladder

43: Flat key

44:C type buckle

45:Screw

Figure 1 is a schematic diagram of a linear actuator driving an integrated planetary gear with two actuating rods at radial ends sequentially along the circumferential direction.

Figure 2 is a cross-sectional view of a reduced power assist device for an electric bicycle according to an embodiment of the present invention.

In order to help the review committee further understand the technical features and means of the present invention, specific embodiments are described in detail with illustrations as follows: Please refer to Figures 1 to 2 at the same time. Figure 2 is a reduced electric bicycle power assist according to an embodiment of the present invention. Cutaway view of the device. In the embodiment of the present invention, the hub shell of the reduced electric bicycle power-assist device includes a shell main 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 locked to the shell main body 31 by screws 34. Actually, When used, the hub shell can be connected to the wheel frame (not shown) through spokes (not shown), and the hub shell drives the wheel rim to rotate. The left fixed axis 42 and the right fixed axis 41 have a left fixed axis step 421 at the right end, and a right fixed axis step 411 at the left end of the right fixed axis 41. The left fixed axis 42 and the right fixed axis 41 are connected by the left fixed axis 42 and the right fixed axis 41. The ball bearing 36, the left seal 38 and the right ball bearing 35 and the right seal 37 are arranged on the central axis of the hub shell. The parts of the left fixed shaft 42 and the right fixed shaft 41 exposed outside the hub shell can be connected by nuts (not shown). (pictured) is locked on the front fork or rear fork (not shown) of the frame. The harmonic gear reduction mechanism includes a rigid ring gear 11, an integrated planetary gear 12, a left flexible gear 13 and a right rigid ring cup 14. The rigid ring gear 11 is fixed on the left side using a flat key 43 and two C-shaped buckles 44. The fixed shaft 42, the right rigid ring cup 14 is locked in the housing body 31 by screws 39, and the flexible bearing 15 is interference-fitted to the left flexible gear. 13 inner diameter. The linear actuator 21 has a plurality of radial execution rods. The plurality of radial execution rods include an actuated execution rod 22 and other non-actuated execution rods 23. The linear actuator 21 has two actuated radial ends. An execution rod 22 is used to drive and support the movement of the integrated planet wheel 12.

The linear actuator 21 is placed in the internal hollow space of the harmonic gear reduction mechanism, and its left and right sides are locked to the left fixed-axis step 421 and the right fixed-axis step 411 by screws 45, and has a plurality of linear actuator rods in the radial direction. The actuator 21 drives the movement of the integrated planet gear 12 with the two actuated execution rods 22 at the radial end in sequence along the circumferential direction. When the next two adjacent radial end execution rods are actuated, they contact the inside of the integrated planet gear 12 When the flexible bearing 15 is turned on, the two previously actuated actuating rods 22 return to the undriven position, and so on again and again by the actuating rods (22 and 23) of the linear actuator 21 and through the number of teeth of the left flexible gear 13 and the rigid ring gear 11 The difference drives the left flexible gear 13 to rotate around the fixed rigid ring gear 11. At the same time, the right rigid ring cup 14 locked in the shell body 31 drives the hub shell to output the left ball bearing 36 and the right ball bearing 35. Turn.

In summary, the miniaturized power-assisting device for electric bicycles of the present invention is obviously capable of achieving a high reduction ratio and improving the power-assisted effect in a smaller size. The structural features specifically defined in the claims of the present invention are not found in similar items, and it is industrially applicable and novel. It is innovative and progressive and has met the requirements for an invention patent. It is very convenient for me to file an application in accordance with the law and pray for review and grant of a patent.

11: Rigid ring gear

12: Integrated planetary wheel

13:Left flexible gear

14: Right rigid ring cup

15:Flexible bearings

21: Linear actuator

22: The execution rod has been actuated

31: Shell body

32: Cover on the right side of the shell

33: Cover on the left side of the shell

34:Screw

35: Right ball bearing

36: Left side ball bearing

37:Right seal

38:Left seal

39:Screw

41: Right fixed axis

411: Right fixed axis ladder

42: Left fixed axis

421: Left fixed axis ladder

43: Flat key

44:C type buckle

45:Screw

Claims (1)

A reduced power-assisting device for electric bicycles, including: The hub shell includes a shell main body, a right side cover and a left side cover. The right side cover and the left side cover are locked to the main body with screws. The hub shell can be connected to and drive the wheel rim to rotate; The left fixed shaft and the right fixed shaft have a left fixed shaft step on the right end, and a right fixed shaft step on the left end of the right fixed shaft. The left fixed shaft and the right fixed shaft are connected by ball bearings and seals on the left and right sides. It is arranged on the central axis of the wheel hub shell. The parts of the left fixed shaft and the right fixed shaft exposed outside the wheel hub shell can be connected to the front fork or rear fork of the frame; The harmonic gear reduction mechanism includes a rigid ring gear and an integrated planetary gear train with a flexible gear on the left and a rigid ring cup on the right. The rigid ring gear is fixed to the fixed shaft on the left by a flat key and two C-shaped retaining rings, and the rigid ring cup on the right It is locked in the main body of the housing by screws, and a flexible bearing is interference-fitted to the inner diameter of the left flexible gear; The linear actuator has a plurality of radial actuator rods, which can drive the harmonic gear reduction mechanism at high speed, and then the harmonic gear reduction mechanism transmits it to the hub shell with a high reduction ratio; Its characteristics are: The linear actuator is placed in the hollow space inside the harmonic gear reduction mechanism to support and drive the movement of the integrated planetary gear. The left and right sides of the linear actuator are locked to the left fixed-axis step and the right fixed-axis step with screws. , a linear actuator with a plurality of radial actuating rods drives the integrated planet gear with two actuated actuating rods at the radial end in sequence along the circumferential direction. When the next two adjacent actuating rods at the radial end actuate and contact the integrated planetary gear, When the flexible bearing inside the planet wheel is used, the two previously actuated actuators return to the undriven position, and so on again and again by the actuator rods of the linear actuator. Through the difference in the number of teeth between the left flexible gear and the rigid ring gear, the integrated planetary wheel of the harmonic gear reduction mechanism is driven to rotate. At the same time, the two bearings of the hub shell on the left fixed axis and the right fixed axis are driven to perform output rotation.

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