TWI860238B - Driving apparatus of an electrically assisted bicycle - Google Patents

Abstract

An electrically assisted bicycle is provided with a driving apparatus comprising a motor, an epicyclic gearing, an annular supporting element and two shafts. The epicyclic gearing includes a reduced sun gear supported on a reduced section of the tubular mandrel of the motor. The annular supporting element is connected to a chain ring. The left shaft extends throughout the tubular mandrel and includes a left end connected to a crank, a right end, and a reduced section extending throughout the reduced section of the tubular mandrel. The right end is slenderer than the left end. The right shaft includes a right end connected to another crank and a left end connected to the right end of the left shaft so that they are rotatable together. A clutch is arranged between the epicyclic gearing and the annular supporting element. Another clutch is arranged between the right shaft and the epicyclic gearing.

Description

Electric-assisted drive device for electric-assisted bicycles

The present invention relates to a bicycle, and more particularly to an electric-assisted driving device for an electric-assisted bicycle.

An electric-assisted driving device for an electric-assisted bicycle has a motor, a planetary gear set, two clutches, an annular support and a crank set. The motor is arranged in a five-way tube of a bicycle. The motor has a tubular iron core. The planetary gear has a sun gear arranged on the tubular iron core. The crank set has an axle and two cranks. The axle passes through the tubular iron core, but the two are not connected, that is, the axle can rotate relative to the tubular iron core. The first clutch is placed between the tubular iron core and the annular support. The second clutch is placed between the annular support and the axle. The annular support member is connected to at least one gear. The gear is connected to at least one flywheel via a chain. The flywheel is connected to a rear wheel of the bicycle.

The simple way to calculate the planetary gear reduction ratio is: the number of teeth on an inner ring is divided by the number of teeth on the sun gear, and the resulting number is added with a fixed coefficient of 1, which is the reduction ratio. When the number of teeth on the inner ring is fixed, the reduction ratio is determined by the number of teeth on the sun gear.

As mentioned above, the shaft passes through the tubular core, and the tubular core carries the sun gear. The diameter of the shaft determines the inner and outer diameters of the tubular core. The outer diameter of the tubular core determines the inner and outer diameters of the sun gear, that is, the number of teeth. Because it must match the two cranks, the diameter of the shaft is fixed, the number of teeth of the sun gear is fixed, and the speed reduction ratio is fixed. Unless the inner gear ring is made larger, but this is an unpopular structural design.

The main purpose of the present invention is to provide an electric-assisted driving device for an electric-assisted bicycle that is smaller or has a better speed reduction ratio.

To achieve the above-mentioned purpose, the driving device includes a motor, a planetary gear set, an annular support, a left shaft, a right shaft and two clutches. The motor is arranged in a five-way tube of a bicycle, and has a tubular iron core, and the tubular iron core has a small diameter section. The planetary gear set has a small sun gear arranged in the small diameter section of the tubular iron core. The annular support is connected to at least one gear. The left shaft passes through the tubular iron core. The left end of the left shaft is connected to a crank. The left shaft has a small diameter section passing through the small diameter section of the tubular iron core. The right end of the left shaft is smaller than the left end thereof. The right end of the right shaft is connected to another crank. The left end of the right shaft is connected to the right end of the left shaft, so that the left and right shafts rotate together. The first clutch is disposed between the planetary gear set and the annular support. The second clutch is disposed between the right shaft and the planetary gear set.

In order to make the purpose, features and advantages of the present invention easy to understand, one or more preferred embodiments are given below with detailed descriptions in conjunction with the attached drawings.

10: Motor

12: Planetary gear set

14, 16: Clutch

18: Ring support

20: Shell

22: Tubular iron core

23: Small path section

24: Left axis

26: Right axis

28: Left end

30: right end

32: Main diameter section

34: Small path section

36: Sun gear

38: Right end

40: Left end

42: Square hole

44: Frame

46: Steel Ball

48: Spring

50: Ring

52: Center hole

54: Groove

56: Peripheral holes

58: Non-circular part

60: Non-circular hole

62: Teeth

64: Claw

Figure 1 is a three-dimensional diagram of a preferred embodiment of the electric-assisted driving device of the present invention applicable to an electric-assisted bicycle.

Figure 2 is an exploded view of the power-assisted drive device shown in Figure 1.

Figure 3 is a cross-sectional view of the power-assisted drive device shown in Figure 1.

Figures 4 and 5 are front views of a clutch of an electrically assisted drive device in the disengaged and engaged states.

Figures 6 and 7 are front views of another clutch of the electrically assisted drive device in the disengaged and engaged states.

Next, the embodiments of the present invention are described in conjunction with the attached drawings. In the attached drawings, the same reference numerals are used to represent the same or similar structures or units. It is foreseeable that the embodiments described are only examples of part of the present invention, not all of the embodiments. Other embodiments can be derived based on the examples described, or structures that can be modified or changed as needed are all within the scope of protection of the present invention.

In the following description, directional terms such as "up", "down", "left", "right", "front", "back", "inside", "outside" and "side" are only used to refer to the directions of the attached drawings. The use of directional terms is for better and clearer description and understanding of this case, and does not express or imply that the device or component described must have a specific orientation, structure and operation, so it cannot be understood as a limitation on the technical content of this case.

Unless otherwise specified and clearly defined, in the following description, "installed", "connected", "connected" or "located on" should be understood in a broad sense, such as fixed connection, detachable connection, integral connection, mechanical connection, direct connection, indirect connection or connection between two components. For technicians in the field of this case, they can understand the specific meanings of the above terms in various embodiments and even this case based on their general knowledge or experience.

Unless otherwise specified, in the following descriptions, "plurality" means two or more.

Referring to FIGS. 1 to 3, according to a preferred embodiment of the present invention, an electric-assisted driving device for an electric-assisted bicycle has a motor 10, a planetary gear set 12, two clutches 14 and 16, an annular support member 18, and a crankshaft set. The motor 10 is disposed in a bottom bracket (not shown) of a bicycle. The motor 10 has a housing 20, a tubular core 22, a set of magnets (not shown), and a set of coils (not shown). The housing 20 accommodates the tubular core 22, the set of magnets, and the set of coils. The set of magnets is attached to the tubular core 22. The core 22 has a small diameter section 23.

The planetary gear 12 has a sun gear 36 disposed in the small diameter section 23 of the tubular core 22.

The crankshaft assembly has a left shaft 24 and a right shaft 26. The left shaft 24 passes through the tubular iron core 22, but the two are not connected, that is, the left shaft 24 can rotate relative to the tubular iron core 22. The clutch 14 is placed between the tubular iron core 22 and the annular support 18. The clutch 16 is placed between the annular support 18 and the right shaft 26. The annular support 18 is connected to at least one gear (not shown). The gear is connected to at least one flywheel (not shown) via a chain (not shown). The flywheel is connected to a rear wheel of the bicycle (not shown).

The left shaft 24 has a left end 28, a right end 30, a large diameter section 32 and a small diameter section 34. The large diameter section 32 is adjacent to the left end 28. The left end 28 and the right end 30 are both square sections. The left end 28 can be inserted into a square hole of a left crank (not shown). The small diameter section 34 is adjacent to the right end 30. The large diameter section 32 and the small diameter section 34 are adjacent. The diameter of the large diameter section 32 is the same as the diameter of a general crankshaft. The diameter of the small diameter section 34 is smaller than the diameter of a general crankshaft.

The small diameter section 34 of the left shaft 24 passes through the small diameter section 23 of the tubular iron core 22. The small diameter section 34 of the left shaft 24 and the small diameter section 23 of the tubular iron core 22 allow the diameter of the solar gear 36 to be smaller than the diameter of the solar gear of the planetary gear set of a general power-assisted drive device. Therefore, the planetary gear set 12 can provide a better reduction ratio than the planetary gear set of a general power-assisted drive device.

The right shaft 26 has a right end 38 and a left end 40. The right end 38 is inserted into a square hole of a right crank (not shown). The left end 40 of the right shaft 26 has a square hole 42 to accommodate the right end 30 of the left shaft 24. Therefore, the right shaft 26 does not rotate relative to the left shaft 24, that is, the two can only rotate together.

Referring to Figures 2, 3 and 6, the clutch 14 is composed of a frame 44 of the gear set 12, a plurality of steel balls 46, a plurality of springs 48 and a ring 50. The frame 44 has a central hole 52, a plurality of grooves 54 and a plurality of peripheral holes 56. The central hole 52 is connected to each groove 54. Each groove 54 is connected to an adjacent peripheral hole 56. Each groove 54 widens from the central hole 52 to its corresponding peripheral hole 56. The central hole 52 accommodates the ring 50. Each groove 54 accommodates a single steel ball 46. Each peripheral hole 56 accommodates a single spring 48.

There is a non-circular portion 58 on the right side of the ring 50. There is a non-circular hole 60 on the left side of the annular support member 18 to accommodate the non-circular portion 58. Therefore, the ring 50 cannot rotate relative to the annular support member 18, that is, the two can only rotate together. In another embodiment, the ring 50 and the annular support member 18 can be made into one piece.

Referring to Figures 2 and 4, the clutch 16 is composed of a plurality of teeth 62 and a plurality of claws 64. The plurality of teeth 62 are formed on the inner side of the annular support member 18. The plurality of claws 64 are pivotally connected to the right shaft 26, and the former elastically expands from the latter. Each claw 64 can abut against one tooth 62.

When stationary, clutches 14 and 16 are both in the disengaged state (Figures 4 and 6).

When only human power is used, the clutch 16 is in the closed state (Figure 5), and the clutch 14 is in the released state (Figure 6).

When there is only electricity, the clutch 14 is in the closed state (Figure 7), and the clutch 16 is in the open state (Figure 4).

When using human power or electric power, the clutch 16 is in the closed state (Figure 5), and the clutch 14 is in the closed state (Figure 7).

Clutches 14 and 16 are prior art and are not described in further detail.

Without departing from the broad concept of this case, those familiar with this technology can understand and make changes to the above-mentioned embodiments. Therefore, this case is not limited to the specific embodiments disclosed in the specification. All modifications made according to the spirit and technical scope of this case should be covered and protected by the text content defined in the scope of the patent application.

10: Motor

12: Planetary gear set

14, 16: Clutch

18: Ring support

20: Shell

22: Tubular iron core

23: Small path section

24: Left axis

26: Right axis

28: Left end

30: right end

32: Main diameter section

34: Small path section

36: Sun gear

38: Right end

40: Left end

42: Square hole

44: Frame

50: Ring

58: Non-circular part

60: Non-circular hole

62: Teeth

64: Claw

Claims (2)

An electric-assisted driving device for an electric-assisted bicycle comprises: a motor (10) disposed in a bottom bracket of a bicycle, the motor (10) having a tubular iron core (22), the tubular iron core (22) having a small diameter section (23); a planetary gear set (12) comprising: a small solar gear (36) disposed in the small diameter section (23) of the tubular iron core (22); an annular support member (18) connected to at least one gear plate; a left shaft (24) passing through the tubular iron core (22), the left shaft (24) comprising: a left end (28) connected to a crank ; a right end (30) smaller than the left end (28); a small diameter section (34) penetrating the small diameter section (23) of the tubular core (22); a right shaft (26) comprising: a right end (38) connected to another crank; a left end (40) connected to the right end (30) of the left shaft (24) so that the right shaft (26) rotates together with the left shaft (24); a first clutch (14) disposed between the planetary gear set (12) and the annular support member (18); and a second clutch (16) disposed between the right shaft (26) and the planetary gear set (12). The electric-assisted driving device of the electric-assisted bicycle as described in claim 1, wherein the right end (30) of the left shaft (24) is a square segment, and the left end (40) of the right shaft (26) has a square hole (42), and the square hole (42) accommodates the square right end (30) of the left shaft (24).

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