TW202126932A - Harmonic drive system for pedal electric cycle - Google Patents

Abstract

A harmonic drive system for a pedal electric cycle configured in a bottom bracket shell comprises a case, a motor stator, a motor rotor, a bearing, a first one-way clutch, an output shaft, a flexible bearing, a flexible flexspline, a cross roller bearing, a connecting member, a second one-way clutch and a torque sensor. The motor rotor is disposed inside an inner surface of the motor stator. The second one-way clutch and the bearing are disposed inside an inner surface of the motor rotor. One end of the output shaft is disposed inside an inner surface of the second one-way clutch and an inner surface of the bearing. The other end of the output shaft has an elliptical cam disposed inside an inner surface of the flexible bearing. The flexible bearing is disposed inside an inner surface of a main body of the flexible flexspline. The main body has an external toothed gear provided for engaging with an internal toothed gear of an inner ring of the cross roller bearing. The motor stator and the inner ring are fixed at the case. An extension part of the flexible flexspline is connected to an outer ring of the cross roller bearing and one end of the connecting member. The first one-way clutch is disposed inside an inner surface of the other end of the connecting member. The torque sensor is disposed inside an inner surface of the first one-way clutch. One end of the torque sensor is connected to a sprocket of the pedal electric cycle. A bottom bracket of the pedal electric cycle is disposed inside an inner surface of the torque sensor.

Description

Harmonic drive system of electric moped

The present invention relates to a harmonic drive system of an electric booster, in particular to an electric booster drive system with a harmonic reducer.

Please refer to FIG. 7, which is a schematic cross-sectional view of a specific embodiment of a planetary gear transmission device for an electric bicycle in the prior art. The planetary gear transmission device 9 includes an electric motor 92, a hollow connecting shaft 93, a braking device 98, a hollow gear 94, a sun gear 96, three planetary gears 95 and a planetary gear carrier 99. Please refer to FIG. 8 at the same time, which is a partial enlarged cross-sectional view of the prior art embodiment of FIG. 7. The ring gear 94 has an internal gear and an external gear. The center wheel 96 has an external gear. The three planetary gears 95 each have an external gear. The three planetary gears 95 are meshed with the inner gear of the ring gear 94 and the outer gear of the sun gear 96, respectively. The planetary gear carrier 99 is connected to three planetary gears 95 respectively. The outer gear train of the hollow wheel 94 meshes with the link of a chain 97 of an electric bicycle. A central shaft 91 of the electric bicycle passes through the center of the hollow connecting shaft 93 and is fixedly connected to the planetary gear carrier 99. The hollow connecting shaft 93 is fixedly connected to the electric motor 92 and is also fixedly connected to the center wheel 96 at the same time. The conventional technology uses planetary gear transmission 9, which mainly has the disadvantages of low speed reduction, heavier weight, larger volume, higher noise, and lower transmission accuracy. Due to problems such as low deceleration and heavier weight, the demand for electric motors is relatively large, which in turn affects the battery's endurance. In addition, high noise and low transmission accuracy will affect the comfort of the user when riding. Furthermore, the larger size will affect the aesthetic design of the electric moped.

In view of this, the inventor developed a design that is easy to assemble, which can avoid the above shortcomings, is easy to install, and has the advantages of low cost, in order to take into account the flexibility and economy of use. Therefore, the present invention is born.

The technical problem to be solved by the present invention is how to reduce the weight, volume and noise of the harmonic drive system of the electric bicycle, and at the same time increase the reduction ratio of the harmonic drive system of the electric bicycle, and improve the transmission accuracy, thereby improving battery life and riding Timely comfort and improved aesthetic design.

In order to solve the aforementioned problems and achieve the expected effect, the present invention provides a harmonic drive system for an electric bicycle, which is arranged in a five-way pipe of a frame of an electric bicycle. , A motor stator, a motor rotor, at least one second bearing, a first one-way clutch, a motor output shaft, at least one first bearing, a flexible bearing, a flexible wheel, a cross roller bearing, a connecting piece , A second one-way clutch and a torque sensor. The motor stator is fixed on the housing. The motor stator has an inner ring. The motor rotor is housed in the inner ring of the motor stator. The motor rotor has an inner ring. Each at least one second bearing has an inner ring. The second one-way clutch and at least one second bearing system are housed in the inner ring of the motor rotor. The second one-way clutch has an inner ring. The motor output shaft has an inner ring. A first end of the motor output shaft is accommodated in the inner ring of the second one-way clutch and the inner ring of each at least one second bearing. A second end of the motor output shaft has an elliptical cam. The motor rotor, motor stator and motor output shaft form an electric motor. At least one first bearing is accommodated in the inner ring of the first end of the motor output shaft. Each at least one first bearing has an inner ring. The flexible bearing has an inner ring. The flexible bearing system is used to accommodate the elliptical cam at the second end of the motor output shaft, so that the flexible bearing is shaped Becomes an ellipse. The elliptical cam at the second end of the motor output shaft and the flexible bearing form a wave generator. The flexspline includes a flexspline body and an extension part of the flexspline. The flexible wheel body has an inner ring. A first end of the flexspline body has an external gear. The wave generator is accommodated in the inner ring of the first end of the flexspline body, so that the first end of the flexspline body is shaped into an oval shape. The flexspline extension part is connected with a second end of the flexspline body. The extension part of the flexspline extends outward from the second end of the flexspline body, so that the flexspline forms a hat shape. The crossed roller bearing includes a crossed roller bearing inner ring, a crossed roller bearing outer ring and a plurality of crossed rollers. One of the first ends of the inner ring of the cross roller bearing is fixed on the shell. The first end of the inner ring of the cross roller bearing has an internal gear for meshing with the external gear of the first end of the flexspline body. A second end of the inner ring of the cross roller bearing has an inner ring and an outer groove. The inner ring of the second end of the inner ring of the crossed roller bearing is used for accommodating the second end of the flexspline body. The outer ring of the cross roller bearing has an inner ring and an inner groove. The inner ring of the outer ring of the crossed roller bearing is used to accommodate the second end of the inner ring of the crossed roller bearing. The inner groove of the outer ring of the crossed roller bearing is located corresponding to the outer groove of the inner ring of the crossed roller bearing, so that the inner groove of the outer ring of the crossed roller bearing and the outer groove of the inner ring of the crossed roller bearing are located between A cross-roller accommodating space is formed. A plurality of cross rollers are accommodated in the cross roller accommodating space. The connecting piece has a first end and a second end. The flexspline extension part of the flexspline is respectively connected with the outer ring of the cross roller bearing and the first end of the connecting piece. The second end of the connecting piece has an inner ring. The first one-way clutch is accommodated in the inner ring of the second end of the connecting piece. The first one-way clutch has an inner ring. The torque sensor has an inner ring. A first end of the torque sensor is housed in the inner ring of the first one-way clutch. The first end of the torque sensor is connected with a chain disc of the electric bicycle. The inner ring of each at least one first bearing and the inner ring of the torque sensor are used for accommodating a central shaft of the electric bicycle. The second end of the torque sensor is connected with the central shaft of the electric bicycle.

In an embodiment, in the aforementioned harmonic drive system for an electric bicycle, at least one second bearing system includes at least one selected from the following group: a ball bearing and a needle bearing.

In the embodiment, in the aforementioned harmonic drive system of the electric moped, the second end of the torque sensor is housed in the inner ring of the second end of the motor output shaft.

In an embodiment, the aforementioned harmonic drive system for an electric bicycle further includes a third bearing, wherein the second end of the motor output shaft further includes an extension, and the second end of the connecting piece further includes an extension, and the connecting piece The extension at the second end has an inner ring for accommodating the third bearing, and the third bearing has an inner ring for accommodating the extension at the second end of the motor output shaft.

In an embodiment, in the aforementioned harmonic drive system of an electric bicycle, the third bearing system includes at least one selected from the following group: a ball bearing and a needle bearing.

In the embodiment, the aforementioned harmonic drive system for electric bicycles further includes a fourth bearing, wherein the fourth bearing has an inner ring, and the first end of the motor output shaft is housed in the inner ring of the fourth bearing. In the inner ring of the motor rotor, the fourth bearing is located between the motor rotor and the second end of the motor output shaft.

In the embodiment, in the aforementioned harmonic drive system for an electric bicycle, the fourth bearing system includes at least one selected from the following group: a ball bearing and a needle bearing.

In the embodiment, the aforementioned harmonic drive system for electric bicycles further includes a fifth bearing, and the first end of the motor output shaft further includes an extension, wherein the fifth bearing has an inner ring, and the first end of the motor output shaft The extension of the end is accommodated in the inner ring of the fifth bearing.

In an embodiment, the aforementioned harmonic drive system for an electric bicycle further includes a retaining ring for the first shaft, wherein the fifth bearing has a fifth bearing inner ring, and the first end of the motor output shaft further includes a fixing part, The retaining ring for the first shaft and the fixing part of the first end of the motor output shaft are used for Fix the fifth bearing inner ring of the fifth bearing on the motor output shaft.

In the embodiment, in the aforementioned harmonic drive system for an electric bicycle, the fifth bearing system includes at least one selected from the following group: a ball bearing and a needle bearing.

In an embodiment, in the aforementioned harmonic drive system for an electric bicycle, at least one first bearing system includes at least one selected from the following group: a ball bearing and a needle bearing.

In the embodiment, in the aforementioned harmonic drive system of an electric moped, the ball bearing is a deep groove ball bearing.

In an embodiment, the aforementioned harmonic drive system for electric bicycles further includes a second shaft retaining ring, at least one first bearing has an inner ring, and the second shaft retaining ring is used to connect at least one first shaft The inner ring of the bearing is fixed on the middle shaft of the electric moped.

In the embodiment, in the aforementioned harmonic drive system for an electric moped, the electric motor includes one selected from the group consisting of a brushless DC motor and a brushed DC motor.

In the embodiment, the aforementioned harmonic drive system for an electric assisted vehicle further includes a battery, wherein the battery is electrically connected to the electric motor.

In the embodiment, in the aforementioned harmonic drive system for an electric assisted vehicle, the battery is a rechargeable battery.

In the embodiment, in the aforementioned harmonic drive system of an electric assisted vehicle, the battery is arranged in a middle tube or an inclined tube of the frame.

In the embodiment, in the aforementioned harmonic drive system for electric mopeds, the first end of the cross roller bearing inner ring of the cross roller bearing, the flexspline and the wave generator form a harmonic reducer, and the harmonic reducer has The rotating shaft system of a harmonic reducer coincides with a motor output rotating shaft of the motor output shaft.

In the embodiment, in the aforementioned harmonic drive system of the electric moped, the rotation axis of the harmonic reducer coincides with an input rotation axis of the torque sensor.

In the embodiment, in the aforementioned harmonic drive system for electric mopeds, the first end of the cross roller bearing inner ring of the cross roller bearing, the flexspline and the wave generator form a harmonic reducer, and the harmonic reducer has A rotating shaft system of a harmonic reducer coincides with an input rotating shaft of the torque sensor.

In order to further understand the present invention, the following is a detailed description of the specific components of the present invention and the effects achieved by the following preferred embodiments, in conjunction with the drawings and figure numbers.

1‧‧‧Harmonic drive system of electric moped

10‧‧‧Frame

11‧‧‧Five-way tube

12‧‧‧Central tube

13‧‧‧ Inclined pipe

14‧‧‧Shell

15‧‧‧Chain Disc

16‧‧‧Bottom Axis

17‧‧‧One-way ratchet

2‧‧‧Electric Motor

20‧‧‧Motor stator

21‧‧‧Motor rotor

22‧‧‧Motor output shaft

23‧‧‧Inner ring of motor output shaft

24‧‧‧The first end of the motor output shaft

240‧‧‧The extension of the first end of the motor output shaft

25‧‧‧The second end of the motor output shaft

26‧‧‧Oval cam

27‧‧‧Extension of the second end of the motor output shaft

28‧‧‧Fixed part of the first end of the motor output shaft

29‧‧‧Motor output rotating shaft

3‧‧‧wave generator

30‧‧‧Flexible bearing

31‧‧‧Inner ring of flexible bearing

32‧‧‧Harmonic reducer

33‧‧‧Harmonic reducer rotating shaft

4‧‧‧Flexible wheel

40‧‧‧Flexible wheel body

41‧‧‧The inner ring of the flexible wheel body

42‧‧‧The first end of the flexible wheel body

43‧‧‧External gear

44‧‧‧The second end of the flexible wheel body

45‧‧‧Flexible wheel extension part

5‧‧‧Cross Roller Bearing

51‧‧‧Cross roller bearing inner ring

52‧‧‧Cross roller bearing inner ring first end

53‧‧‧Internal gear

54‧‧‧The second end of the cross roller bearing inner ring

540‧‧‧The second end of the inner ring of the cross roller bearing inner ring

55‧‧‧Outer groove

56‧‧‧Cross roller bearing outer ring

560‧‧‧Cross roller bearing outer ring and inner ring

57‧‧‧Inner groove

58‧‧‧Cross roller housing space

59‧‧‧Cross roller

6‧‧‧Connecting pieces

61‧‧‧The first end of the connecting piece

62‧‧‧The second end of the connecting piece

63‧‧‧The inner ring of the second end of the connecting piece

64‧‧‧The extension of the second end of the connecting piece

65‧‧‧The inner ring of the extension of the second end of the connecting piece

7‧‧‧The first one-way clutch

70‧‧‧Torque Sensor

71‧‧‧The first end of the torque sensor

72‧‧‧The second end of the torque sensor

73‧‧‧Input rotation axis

8‧‧‧The first bearing

80‧‧‧Second Bearing

81‧‧‧Third bearing

82‧‧‧Fourth bearing

83‧‧‧Fifth Bearing

84‧‧‧The fifth bearing inner ring

85‧‧‧Second one-way clutch

86‧‧‧Retaining ring for the first shaft

87‧‧‧Retaining ring for second shaft

88‧‧‧Battery

89‧‧‧Copper sleeve

9‧‧‧Planetary gear transmission

91‧‧‧Bottom Axis

92‧‧‧Electric Motor

93‧‧‧Hollow connecting shaft

94‧‧‧Hollow wheel

95‧‧‧Planetary gear

96‧‧‧Center wheel

97‧‧‧Chain

98‧‧‧Brake device

99‧‧‧Planetary Gear Carrier

Figure 1 is a schematic cross-sectional view of a specific embodiment of a harmonic drive system for an electric assisted vehicle according to the present invention.

Figure 2 is a three-dimensional exploded view of the motor output shaft, flexible bearing, flexspline, cross-roller bearing and connecting parts of the specific embodiment of Figure 1.

Figure 3 is a schematic top view of the combination of the cross-roller bearing, flexspline and wave generator of the specific embodiment shown in Figure 1.

Figure 4 is a schematic cross-sectional view of a specific embodiment of an electric power-assisted vehicle harmonic drive system according to the present invention, which is installed in the frame of the electric power-assisted vehicle.

Figure 5 is a schematic cross-sectional view of another specific embodiment of the harmonic drive system of an electric power-assisted vehicle installed in the frame of the electric power-assisted vehicle of the present invention.

Figure 6 is a schematic flow diagram of the four scenario modes of a harmonic drive system for an electric moped according to the present invention.

Fig. 7 is a schematic cross-sectional view of a specific embodiment of a planetary gear transmission device for electric bicycles in the prior art.

FIG. 8 is a schematic partial enlarged cross-sectional view of the embodiment of the prior art of FIG. 7. FIG.

Please refer to Fig. 1, which is a schematic cross-sectional view of a specific embodiment of a harmonic drive system for an electric bicycle according to the present invention. A harmonic drive system 1 for an electric power-assisted vehicle of the present invention includes a housing 14, a motor stator 20, a motor rotor 21, a motor output shaft 22, a flexible bearing 30, a flexible wheel 4, and a cross roller bearing 5. A connecting piece 6, two first bearings 8, two second bearings 80, a third bearing 81, a fourth bearing 82, one or two fifth bearings 83, a retaining ring 86 for the first shaft, a first A buckle 87 for two shafts, a first one-way clutch 7, a second one-way clutch 85 and a torque sensor 70. The harmonic drive system 1 of the electric power-assisted vehicle is arranged in a five-way pipe 11 of a frame 10 of an electric power-assisted vehicle (please refer to Figs. 4 and 5). The motor stator 20 is fixed on the housing 14. The motor stator 20 has an inner ring. The motor rotor 21 is housed in the inner ring of the motor stator 20. The motor rotor 21 has an inner ring. The two second bearings 80 and the second one-way clutch 85 are housed in the inner ring of the motor rotor 21, and the second one-way clutch 85 is arranged between the two second bearings 80. In some embodiments, the two second bearings 80 include at least one selected from the following group: a ball bearing and a needle bearing, wherein the ball bearing may be a deep groove ball bearing. Please also refer to Fig. 2, which is a three-dimensional exploded view of the motor output shaft, flexible bearing, flexspline, cross-roller bearing and connecting parts of the embodiment of Fig. 1. The motor output shaft 22 has a first end 24 and a second end 25. The first end 24 of the motor output shaft 22 includes a fixing portion 28 and an extension portion 240. The second end 25 of the motor output shaft 22 has an elliptical cam 26. The second end 25 of the motor output shaft 22 further includes an extension 27. The third bearing 81 has an inner ring for accommodating the second end 25 of the motor output shaft 22 的 Extension 27. In some embodiments, the third bearing 81 includes at least one selected from the following group: a ball bearing and a needle bearing, wherein the ball bearing may be a deep groove ball bearing. The fourth bearing 82 has an inner ring. The two second bearings 80 each have an inner ring. The second one-way clutch 85 has an inner ring. The fifth bearing 83 has an inner ring. The inner ring of the fourth bearing 82, the inner rings of the two second bearings 80, and the inner ring of the second one-way clutch 85 are for housing the first end 24 of the motor output shaft 22; the inner ring of the fifth bearing 83 is for The extension 240 of the first end 24 of the motor output shaft 22 is accommodated; the fourth bearing 82 is arranged on one of the two second bearings 80 and the elliptical cam 26 of the second end 25 of the motor output shaft 22 In the meantime, the second one-way clutch 85 is arranged between one of the two second bearings 80 and the other one, and the other of the two second bearings 80 is arranged between the second one-way clutch 85 and the other one of the two second bearings 80. Between the fifth bearing 83. In some embodiments, the fourth bearing 82 includes at least one selected from the following group: a ball bearing and a needle bearing, wherein the ball bearing may be a deep groove ball bearing. The fifth bearing 83 further has a fifth bearing inner ring 84. The retaining ring 86 for the first shaft and the fixing portion 28 of the first end 24 of the motor output shaft 22 are used to connect the fifth bearing inner ring 84 of the fifth bearing 83 It is fixed on the motor output shaft 22 to avoid axial displacement. In some embodiments, the two fifth bearings 83 include at least one selected from the following group: a ball bearing and a needle bearing, wherein the ball bearing may be a deep groove ball bearing. The motor rotor 21, the motor stator 20, the two second bearings 80, the second one-way clutch 85 and the motor output shaft 22 form an electric motor 2. The motor output shaft 22 has a motor output rotating shaft 29. The electric motor 2 includes one selected from the following group: a brushless DC motor and a brushed DC motor. The flexible bearing 30 has an inner ring 31 for accommodating the elliptical cam 26 of the second end 25 of the motor output shaft 22, so that the flexible bearing 30 is shaped into an elliptical shape. The elliptical cam 26 at the second end 25 of the motor output shaft 22 and the flexible bearing 30 form a wave generator 3. The flexspline 4 includes a flexspline body 40 and an extension portion 45 of the flexspline. The flexible wheel body 40 has an inner ring 41. A first end 42 of the flexspline body 40 has an external gear 43. The wave generator 3 (the elliptical cam 26 and the flexible bearing 30 at the second end 25 of the motor output shaft 22) is housed in the inner ring 41 of the flexspline body 40 corresponding to the first end 42 of the flexspline body 40 At the external gear 43, the first end 42 of the flexspline body 40 is shaped into an oval shape. The extension portion 45 of the flexspline is connected to a second end 44 of the main body 40 of the flexspline. The flexspline extension part 45 extends outward from the second end 44 of the flexspline body 40, so that the flexspline 4 forms a hollow hat shape, wherein the flexspline extension part 45 is a part of the cap. The crossed roller bearing 5 includes a crossed roller bearing inner ring 51, a crossed roller bearing outer ring 56 and a plurality of crossed rollers 59. A first end 52 of the inner ring 51 of the cross roller bearing is fixed to the housing 14. The first end 52 of the inner ring 51 of the crossed roller bearing has an inner gear 53 for meshing with the outer gear 43 of the first end 42 of the flexspline body 40. Please refer to Fig. 3 at the same time, which is a schematic top view of the combination of the cross roller bearing, the flexspline and the wave generator in the specific embodiment of Fig. 1. Among them, the first end 52 (internal gear 53) of the cross roller bearing inner ring 51 of the cross roller bearing 5, the flexspline 4 and the wave generator 3 (the elliptical cam 26 of the second end 25 of the motor output shaft 22 and the flexible The bearing 30) forms a harmonic reducer 32. The harmonic reducer 32 has a harmonic reducer rotating shaft 33, wherein the harmonic reducer rotating shaft 33 of the harmonic reducer 32 coincides with the motor output rotating shaft 29 of the motor output shaft 22. A second end 54 of the inner ring 51 of the cross roller bearing has an inner ring 540 and an outer groove 55. The inner ring 540 of the second end 54 of the cross roller bearing inner ring 51 is for receiving the second end 44 of the flexspline body 40. The outer ring 56 of the cross roller bearing has an inner ring 560 and an inner groove 57. The inner ring 560 of the cross-roller bearing outer ring 56 is for accommodating the second end 54 of the cross-roller bearing inner ring 51. The inner groove 57 of the cross roller bearing outer ring 56 is located corresponding to the outer groove 55 of the cross roller bearing inner ring 51, so that the inner groove 57 of the cross roller bearing outer ring 56 and the cross roller bearing inner ring A cross-roller accommodating space 58 is formed between the grooves 55 outside 51. A plurality of cross rollers 59 are accommodated in the cross roller accommodating space 58. The connecting member 6 has a first end 61 and a second end 62. Soft wheel 4 soft The wheel extension part 45 is connected to the cross-roller bearing outer ring 56 and the first end 61 of the connecting member 6 respectively. The second end 62 of the connecting member 6 further includes an extension portion 64. The second end 62 of the connecting member 6 and the extension portion 64 of the second end 62 of the connecting member 6 are accommodated in the inner ring 41 of the flexspline body 40 close to the second end 44 of the flexspline body 40. The extension 64 of the second end 62 of the connecting member 6 has an inner ring 65. The third bearing 81 is accommodated in the inner ring 65 of the extension 64 of the second end 62 of the connecting member 6. The second end 62 of the connecting member 6 has an inner ring 63. The first one-way clutch 7 is housed in the inner ring 63 of the second end 62 of the connecting member 6. The torque sensor 70 has a first end 71 and a second end 72. The first one-way clutch 7 has an inner ring. The first end 71 of the torque sensor 70 is housed in the inner ring of the first one-way clutch 7. The motor output shaft 22 has an inner ring 23. The second end 72 of the torque sensor 70 is accommodated in the inner ring 23 of the motor output shaft 22 near the second end 25 of the motor output shaft 22 and the extension 27 of the second end 25 of the motor output shaft 22. The two first bearings 8 are accommodated in the inner ring 23 of the motor output shaft 22 close to the first end 24 of the motor output shaft 22. The first end 71 of the torque sensor 70 is connected to a chain disc 15 of the electric bicycle. The torque sensor 70 has an inner ring. The two first bearings 8 each have an inner ring. One of the central shaft 16 of the electric bicycle is housed in the inner ring of the two first bearings 8 and the inner ring of the torque sensor 70, and the second end 72 of the torque sensor 70 is connected to the central shaft 16 of the electric bicycle. Phase connection. At least one of the first bearing 8 has an inner ring, and the second shaft retaining ring 87 is used to fix the inner ring of the first bearing 8 to the middle shaft 16 of the electric bicycle to avoid axial displacement. In some embodiments, the two first bearings 8 include at least one selected from the following group: a ball bearing and a needle bearing, wherein the ball bearing can be a deep groove ball bearing. The torque sensor 70 has an input rotating shaft 73, the input rotating shaft 73 of the torque sensor 70 coincides with the harmonic reducer rotating shaft 33 of the harmonic reducer 32, and the torque sensor 70 has The input rotating shaft 73 coincides with the motor output rotating shaft 29 of the motor output shaft 22. Among them, a copper sleeve 89 and a copper sleeve 89 can be added The system is housed in the inner circle of the torque sensor 70. The copper sleeve 89 has an inner ring. Simultaneously accommodate the middle shaft 16 of the electric bicycle in the inner ring of the two first bearings 8, the inner ring of the torque sensor 70 and the inner ring of the copper sleeve 89, so that the middle shaft 16 of the electric bicycle can be rotated It is more stable and avoids axial displacement.

Please refer to FIG. 4, which is a schematic cross-sectional view of a specific embodiment of an electric power-assisted vehicle harmonic drive system according to the present invention installed in the frame of the electric power-assisted vehicle. In this embodiment, the harmonic drive system 1 of the electric bicycle further includes a battery 88, wherein the battery 88 is electrically connected to the electric motor 2 of the harmonic drive system 1 of the electric bicycle. The battery 88 may be a rechargeable battery. The harmonic drive system 1 of the electric moped is installed in the five-way tube 11 of the frame 10 of the electric moped; the battery 88 is installed in the inclined tube 13 of the frame 10.

Please refer to FIG. 5, which is a schematic cross-sectional view of another specific embodiment of an electric power-assisted vehicle harmonic drive system provided in the frame of the electric power-assisted vehicle according to the present invention. In this embodiment, the harmonic drive system 1 of the electric bicycle further includes a battery 88, wherein the battery 88 is electrically connected to the electric motor 2 of the harmonic drive system 1 of the electric bicycle. The battery 88 may be a rechargeable battery. The harmonic drive system 1 of the electric moped is installed in the five-way tube 11 of the frame 10 of the electric moped; the battery 88 is installed in the middle tube 12 of one of the frame 10.

The harmonic drive system 1 of the electric bicycle of the present invention adopts the deceleration structure of the harmonic reducer 32, which can greatly reduce the volume and weight of the harmonic drive system 1 of the electric bicycle, and the harmonic drive system 1 of the electric bicycle can be installed in the electric bicycle The frame 10 of the five-way tube 11 inside. Such a design can improve the flexibility of the design and configuration of other parts such as the middle axle 16, the torque sensor 70, and the first one-way clutch 7 of the electric assisted vehicle. Compared with the prior art, the harmonic drive system of the electric bicycle is externally hung on the outside of the frame, the present invention adopts this structure to connect the whole harmonic drive system of the electric bicycle. The system 1 is hidden in the frame 10 of the electric moped, which can enhance the aesthetic design of the appearance. In addition, the harmonic reducer 32 has the characteristics of high reduction ratio, high meshing rate, small size, light weight, low noise and high transmission accuracy. It is an electric moped harmonic transmission system that can effectively improve battery life and high transmission accuracy. It runs smoothly and improves riding comfort.

When the user rides or uses the electric bicycle with the harmonic drive system 1 of the electric bicycle of the present invention, there are generally the following four situational modes. Please refer to Figure 6, which is a schematic flow diagram of the four scenario modes of the harmonic drive system of an electric moped according to the present invention. Line 1, Line 2, Line 3, and Line 4 in Figure 6 respectively represent Situation Mode 1, Situation Mode 2, Situation Mode 3, and Situation Mode 4. The arrow direction of the line represents the direction that drives the rotation. For example, the line 1 between the central shaft 16 and the torque sensor 70 represents that the central shaft 16 drives the torque sensor 70. Situational mode 1: The system is in a normal riding state. When the user steps on the pedal to make it rotate forward, the middle shaft 16 of the electric bicycle starts to rotate forward. At this time, the torque sensor 70 senses a rotational torque value, and the electric motor 2 starts according to the magnitude of the rotational torque value. Rotation (the output torque of the electric motor 2 is related to the rotational torque value), and the first end 71 of the torque sensor 70 is increased through the harmonic reducer 32 to reduce the torque output by the chain disc 15 of the electric moped Burden; that is, the user steps on the pedal to rotate in the forward direction, driving the middle shaft 16, driving the torque sensor 70, driving the chain plate 15; the motor rotor 21 of the electric motor 2 rotates, driving the second one-way clutch 85, driving the wave The device 3 drives the flexspline 4, drives the connecting piece 6, drives the first one-way clutch 7, and also drives the sprocket 15; while the sprocket 15 rotates via a chain (not shown in the figure) to drive a rear wheel axle (Figure (Not shown in the middle) one of the one-way ratchet wheels 17 drives a rear wheel (not shown in the figure) to rotate. Scenario 2: When the user wants to rotate the pedal in the reverse direction (reverse rotation of the central shaft 16), then the second one-way clutch 85 will work to make the motor output shaft 22 of the electric motor 2 and the motor of the electric motor 2 The rotor 21 is disengaged, and this When the torque value sensed by the torque sensor 70 is zero (because there is no load), the motor rotor 21 of the electric motor 2 stops rotating; that is, the user steps on the pedal to rotate in the opposite direction, driving the central shaft 16 to drive the torque perception The device 70 drives the chain plate 15 to drive the one-way ratchet wheel 17. At this time, the one-way ratchet wheel 17 plays a role so that the rear wheel will not reverse; and the torque sensor 70 also drives the connecting piece 6, drives the flexible wheel 4, and drives the wave generator 3. Drive the second one-way clutch 85. At this time, the second one-way clutch 85 functions to disengage the motor output shaft 22 of the electric motor 2 from the motor rotor 21 of the electric motor 2. Scenario 3: When the battery 88 is empty, the electric motor 2 will not rotate, or when the user does not want to use the electric motor 2 for assistance, cut off the switch so that the electric motor 2 will not rotate. If there is no first one-way clutch 7 at this time, when the user steps on the pedal, the positive rotation of the bottom bracket 16 will not only bring the torque sensor 70 to rotate, and cause the chain plate 15 to rotate in the positive direction, but also the torque sensor 70. This will cause the first one-way clutch 7 and the harmonic reducer 32 to rotate together. However, since the harmonic reducer 32 has a relatively large reduction ratio, the user will feel strenuous when stepping on the pedal. Therefore, in scenario mode 3, the first one-way clutch 7 of the harmonic drive system 1 of the electric assisted vehicle of the present invention can be used to disconnect the first one-way clutch 7 from the harmonic reducer 32, thereby greatly reducing the use of The load caused by the harmonic reducer 32 when the user steps on the pedal; that is, the user steps on the pedal to rotate in the forward direction, driving the middle shaft 16, the torque sensor 70, the chain plate 15, and the one-way ratchet 17 , Drives the rear wheel to rotate; and the torque sensor 70 also drives the first one-way clutch 7. At this time, the first one-way clutch 7 plays a role to disconnect the first one-way clutch 7 from the connecting piece 6 (harmonic reducer 32) . Scenario 4: The user sometimes needs to reverse by pulling the car, the rear wheel reverses, drives the one-way ratchet 17, drives the chain plate 15, drives the torque sensor 70, drives the bottom bracket 16 to reverse; because the torque sensor 70 feels at this time The measured torque value is zero (due to no load), so the motor rotor 21 of the electric motor 2 will not rotate; and at the same time, the torque sensor 70 will drive the first one-way clutch 7, the connecting piece 6, and the flexible wheel 4. Drive the wave generator 3 to drive the second one-way clutch 85, at this time the second single The power clutch 85 works to disengage the motor output shaft 22 of the electric motor 2 from the motor rotor 21 of the electric motor 2 so as to prevent the vehicle from being jammed in the reversing mode.

In some preferred embodiments, the harmonic reducer 32 has a reduction ratio, which is greater than or equal to 20 and less than or equal to 50.

In some preferred embodiments, the external gear 43 has an external gear module. The inner ring 31 of the flexible bearing 30 has a diameter of the inner ring of the flexible bearing. The elliptical cam 26 at the second end 25 of the motor output shaft 22 has a major axis and a minor axis, and the major axis is larger than the minor axis. The long shaft system is greater than or equal to the flexible bearing inner ring diameter plus 1.8 times the external gear modulus, and is less than or equal to the flexible bearing inner ring diameter plus 2.4 times the external gear modulus; the short shaft system is greater than or equal to the flexible bearing The inner ring diameter minus 2.4 times the external gear module, and less than or equal to the flexible bearing inner ring diameter minus 1.8 times the external gear module.

The flexspline external gear 34 has a number of flexspline external teeth. In some preferred embodiments, the number of meshing teeth of the external flexspline gear 34 and the internal flexspline gear 40 is greater than or equal to 15% of the external teeth of the flexspline, and less than or equal to 30% of the external teeth of the flexspline.

The above are the specific embodiments of the present invention and the technical means used. Many changes and corrections can be derived from the disclosure or teaching of this article. They can still be regarded as equivalent changes made to the concept of the present invention. The function of the invention does not exceed the essential spirit covered by the specification and the drawings, and should be regarded as being within the technical scope of the present invention, and shall be explained first.

In summary, based on the content disclosed above, the present invention clearly achieves the intended purpose of the invention, providing a harmonic drive system for electric mopeds, which is extremely valuable for industrial use, and has filed a patent application for invention in accordance with the law.

1‧‧‧Harmonic drive system of electric moped

14‧‧‧Shell

15‧‧‧Chain Disc

16‧‧‧Bottom Axis

2‧‧‧Electric Motor

20‧‧‧Motor stator

21‧‧‧Motor rotor

22‧‧‧Motor output shaft

24‧‧‧The first end of the motor output shaft

240‧‧‧The extension of the first end of the motor output shaft

25‧‧‧The second end of the motor output shaft

26‧‧‧Oval cam

27‧‧‧Extension of the second end of the motor output shaft

28‧‧‧Fixed part of the first end of the motor output shaft

29‧‧‧Motor output rotating shaft

3‧‧‧wave generator

30‧‧‧Flexible bearing

32‧‧‧Harmonic reducer

33‧‧‧Harmonic reducer rotating shaft

4‧‧‧Flexible wheel

40‧‧‧Flexible wheel body

45‧‧‧Flexible wheel extension part

5‧‧‧Cross Roller Bearing

51‧‧‧Cross roller bearing inner ring

52‧‧‧Cross roller bearing inner ring first end

54‧‧‧The second end of the cross roller bearing inner ring

55‧‧‧Outer groove

56‧‧‧Cross roller bearing outer ring

57‧‧‧Inner groove

58‧‧‧Cross roller housing space

59‧‧‧Cross roller

6‧‧‧Connecting pieces

61‧‧‧The first end of the connecting piece

62‧‧‧The second end of the connecting piece

64‧‧‧The extension of the second end of the connecting piece

7‧‧‧The first one-way clutch

70‧‧‧Torque Sensor

71‧‧‧The first end of the torque sensor

72‧‧‧The second end of the torque sensor

73‧‧‧Input rotation axis

8‧‧‧The first bearing

80‧‧‧Second Bearing

81‧‧‧Third bearing

82‧‧‧Fourth bearing

83‧‧‧Fifth Bearing

84‧‧‧The fifth bearing inner ring

85‧‧‧Second one-way clutch

86‧‧‧Retaining ring for the first shaft

87‧‧‧Retaining ring for second shaft

89‧‧‧Copper sleeve

Claims (20)

A harmonic drive system for an electric power-assisted vehicle is arranged in a five-way pipe of a frame of an electric power-assisted vehicle. The harmonic drive system of the electric-powered vehicle includes: A shell A motor stator is fixed on the housing, and the motor stator has an inner ring; A motor rotor is housed in the inner ring of the motor stator, and the motor rotor has an inner ring; At least one second bearing, each of the at least one second bearing has an inner ring; A second one-way clutch, the second one-way clutch and the at least one second bearing system are accommodated in the inner ring of the motor rotor, and the second one-way clutch has an inner ring; A motor output shaft having an inner ring, a first end of the motor output shaft is accommodated in the inner ring of the second one-way clutch and the inner ring of each of the at least one second bearing, A second end of the motor output shaft has an elliptical cam, wherein the motor rotor, the motor stator, and the motor output shaft form an electric motor; At least one first bearing is accommodated in the inner ring of the first end of the motor output shaft, and each of the at least one first bearing has an inner ring; A flexible bearing with an inner ring for accommodating the elliptical cam at the second end of the motor output shaft so that the flexible bearing is shaped into an ellipse, wherein the second end of the motor output shaft is The elliptical cam and the flexible bearing form a wave generator; A soft wheel, including: A flexspline body having an inner ring, a first end of the flexspline body has an external gear, and the wave generator is accommodated in the inner ring of the first end of the flexspline body so that the The shape of the first end of the flexspline body becomes an ellipse; and A flexspline extension connected to a second end of the flexspline body, the flexspline extension portion extends outward from the second end of the flexspline body, so that the flexspline forms a cap shape; A crossed roller bearing, including: A crossed roller bearing inner ring, wherein a first end of the crossed roller bearing inner ring is fixed on the housing, and the first end of the crossed roller bearing inner ring has an internal gear for the The external gear of the first end of the flexspline body engages, a second end of the inner ring of the crossed roller bearing has an inner ring and an outer groove, and the second end of the inner ring of the crossed roller bearing is The inner ring is for accommodating the second end of the flexspline body; A crossed roller bearing outer ring, which has an inner ring and an inner groove, the inner ring of the crossed roller bearing outer ring is for accommodating the second end of the crossed roller bearing inner ring, the cross roller The inner groove of the outer ring of the sub-bearing is located corresponding to the outer groove of the inner ring of the crossed roller bearing, so that the inner groove of the outer ring of the crossed roller bearing and the inner groove of the inner ring of the crossed roller bearing A cross-roller accommodating space is formed between the outer grooves; and A plurality of cross rollers are accommodated in the accommodating space of the cross rollers; A connecting piece having a first end and a second end, the flexspline extension part of the flexspline is respectively connected with the cross roller bearing outer ring and the first end of the connecting piece, the connecting piece The second end has an inner ring; A first one-way clutch received in the inner ring of the second end of the connecting member, the first one-way clutch having an inner ring; and A torque sensor having an inner ring, a first end of the torque sensor is accommodated in the inner ring of the first one-way clutch, and the first end of the torque sensor is connected to the electric bicycle A chain disc is connected, the inner ring of each of the at least one first bearing and the torque sensor The inner ring is for accommodating a central shaft of the electric bicycle, and the second end of the torque sensor is connected with the central shaft of the electric bicycle. According to the harmonic drive system of the electric bicycle according to the first item of the scope of patent application, the at least one second bearing system includes at least one selected from the following group: a ball bearing and a needle bearing. The harmonic drive system of the electric bicycle as described in the first item of the scope of patent application, wherein the second end of the torque sensor is accommodated in the inner ring of the second end of the motor output shaft. The harmonic drive system of the electric bicycle described in item 1 of the scope of patent application further includes a third bearing, wherein the second end of the motor output shaft further includes an extension, and the second end of the connecting member is more It includes an extension, the extension of the second end of the connecting piece has an inner ring for accommodating the third bearing, and the third bearing has an inner ring for accommodating the motor output shaft The extension at the second end. According to the harmonic drive system of the electric bicycle as described in item 4 of the scope of patent application, the third bearing system includes at least one selected from the following group: a ball bearing and a needle bearing. For example, the harmonic drive system of the electric bicycle described in the first item of the scope of patent application further includes a fourth bearing, wherein the fourth bearing has an inner ring, and the first end of the motor output shaft is accommodated in the first In the inner ring of four bearings and in the inner ring of the motor rotor, the fourth bearing is located between the motor rotor and the second end of the motor output shaft. According to the harmonic transmission system of the electric bicycle according to the scope of patent application, the fourth bearing system includes at least one selected from the following group: a ball bearing and a needle bearing. For example, the harmonic drive system of the electric bicycle described in the scope of patent application, further includes a fifth bearing, the first end of the motor output shaft further includes an extension, wherein the fifth bearing has an inner ring, The extension of the first end of the motor output shaft is accommodated in the inner ring of the fifth bearing Inside. For example, the harmonic drive system of the electric bicycle described in item 8 of the scope of patent application further includes a retaining ring for the first shaft, wherein the fifth bearing has a fifth bearing inner ring, and the first end of the motor output shaft It further comprises a fixing part, the retaining ring for the first shaft and the fixing part of the first end of the motor output shaft are used for fixing the fifth bearing inner ring of the fifth bearing to the motor output shaft. According to the harmonic drive system of the electric moped in the scope of patent application, the fifth bearing system includes at least one selected from the following group: a ball bearing and a needle bearing. According to the harmonic drive system of the electric bicycle as described in the first item of the scope of patent application, the at least one first bearing system includes at least one selected from the following group: a ball bearing and a needle bearing. For example, the harmonic drive system of the electric bicycle described in item 2, item 5, item 7, item 10 and item 11 of the scope of patent application, wherein the ball bearing is a deep groove ball bearing. For example, the harmonic drive system of the electric bicycle described in the first item of the scope of patent application further includes a retaining ring for the second shaft, the at least one first bearing has an inner ring, and the retaining ring for the second shaft is used for The inner ring of the at least one first bearing is fixed on the central shaft of the electric bicycle. According to the harmonic drive system of the electric moped in the scope of patent application, the electric motor includes one selected from the following group: a brushless DC motor and a brushed DC motor. For example, the harmonic drive system of the electric bicycle described in the first item of the scope of patent application further includes a battery, wherein the battery is electrically connected to the electric motor. For the harmonic drive system of the electric bicycle described in item 15 of the scope of patent application, the battery is a rechargeable battery. For the harmonic drive system of the electric booster vehicle described in item 15 of the scope of patent application, the battery is arranged in a middle tube or an inclined tube of the frame. The harmonic drive system of the electric bicycle as described in item 1 of the scope of patent application, wherein the first end of the inner ring of the cross roller bearing of the cross roller bearing, the flexspline and the wave generator form a harmonic deceleration A rotation axis of a harmonic reducer of the harmonic reducer coincides with a rotation axis of a motor output of the motor output shaft. In the harmonic drive system of the electric bicycle described in item 18 of the scope of patent application, the rotation axis of the harmonic reducer coincides with an input rotation axis of the torque sensor. The harmonic drive system of the electric bicycle as described in item 1 of the scope of patent application, wherein the first end of the inner ring of the cross roller bearing of the cross roller bearing, the flexspline and the wave generator form a harmonic deceleration A harmonic reducer rotation axis system of the harmonic reducer coincides with an input rotation axis of the torque sensor.

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