GB2414452A

GB2414452A - Drive unit for electrically assisted pedal cycle

Info

Publication number: GB2414452A
Application number: GB0500562A
Authority: GB
Inventors: Te-Yu Perng
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-05-24
Filing date: 2005-01-12
Publication date: 2005-11-30
Anticipated expiration: 2025-01-12
Also published as: GB0500562D0; FR2870507B3; JP3109879U; FR2870507A3; GB2414452B; TWM257327U

Abstract

An electric bicycle power structure includes a motor 10 a power exchange device 20 and crank assembly 30; and provides power through motor or pedaling means, wherein the power exchange device 20 automatically switches between power generating means. The invention is characterized that, the power exchange device is consisted of an epicyclic gearbox 21, a clutch and a chain wheel assembly 23. The power exchange device is located between the motor 10 and the chain wheel assembly and is capable of directly switching between power generating means. A single direction coupling allows the crank assembly to freewheel under electric-drive conditions. A conventional chain transmission is employed for driving the cycle's rear wheel.

Description

24 1 4452

ELECTRIC BICYCLE POWER STRUCTURE

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The invention relates to an electric bicycle power structure, and more particularly, to an electric bicycle power structure comprising a motor, a power exchange device and pedal interlocking shafts and providing power through the motor or pedaling means, wherein the power exchange device automatically switches between power generating means for accomplishing power save effects and as well as providing enhanced usage conveniences.

(b) Description of the Prior Art

Thanks to uplifting of environmental protection awareness for reducing environmental pollution, a second transportation means is commonly adopted. Using bicycles or electric bicycles as transportation means for short-distance or shopping trips is not only free from resulting in pollution, but also solves an issue as lack of exercise of modern people. Take a prior electric bicycle for an example, an electric motor is installed at the bicycle and is for providing electric power through electric cells. A front wheel or a rear wheel of the bicycle is impelled using a belt so as to provide the bicycle with power for moving forward. When pedaling I according to prior art, gear plates are driven by a rotation chain in order to provide power. However, for the aforesaid electric bicycle, a switching device is needed for switching between electric cells or pedaling means that provide the bicycle with power for moving forward or backward. With respect to usage of the bicycle, power is merely offered at a specific moment relative to one direction and thus incurring complications during usage. Moreover, parts like the switching device and belt are additionally installed to further unnecessarily expanding production costs.

Therefore, the invention provides a power structure that devises pedals and a motor thereof as coaxial members without affecting each other during rotation, such that power is produced by simultaneous I pedaling and motor means, or selectively by either the motor or pedaling means to further move the bicycle forward or backward. Using the power exchange device to determine whether pedaling or motor means outputs greater power, a sequence of assistant power is adjusted, thereby achieving power saving effects, providing enhanced usage conveniences, and effectively reducing production costs without having I to make great modifications to the existing main body and cutting out - 2 numbers of parts of the bicycle.

SUMMARY OF THE INVENTION

In view of the aforesaid shortcomings of prior art, the primary object of the invention is to provide a power structure particularly applied to an electric bicycle, and being capable generating power while automatically switching between pedaling or motor means, thereby achieving power saving effects, offering enhanced usage conveniences by eliminating switching complications, and reducing production costs.

To accomplish the aforesaid object, the electric bicycle power structure according to the invention comprises a motor, a power exchange device and pedal interlocking shafts. The motor has an axis in form of a hollow tube, which is provided with a gear at an appropriate position at a front end thereof. The power exchange device has a planet decelerating mechanism, a clutch and a chain wheel cover; is connected to an interio! of the planet decelerating mechanism having a front end thereof disposed with the clutch. The axis has a center thereof pivotally disposed with a central axis of the pedal interlocking shaft, wherein the central axis has outer covers at two sides thereof.

Each of the outer covers is disposed with a roller bearing at an interior thereof, and is accommodated around an outer wall of the axis. A position where the pedal interlocking shaft at one side of the bicycle joins with the chain wheel cover is provided with the joining cover. The joining cover is disposed with a one-directional axis at an interior thereof; and has a front end thereof accommodated by an inner wall of the outer S cover of the pedal interlocking shaft, and a rear end thereof fastened in the chain wheel cover. The chain wheel cover is disposed with a plurality of teeth at an outer wall thereof, and is connected to an existing transmission system of the bicycle to provide power.

According to the aforesaid structure, when a rotational speed of motor means is greater than that of pedaling means, power produced by the motor is consequently larger than that produced by pedaling. Energy generated from rotation is inputted to the planet decelerating mechanism by the axis of the motor, so that the rotational speed is lowered to increase torque during rotation. The front end of the planet decelerating mechanism is directly joined with the clutch, such that the gear at the outer side of the chain wheel cover is impelled and rotated by leaning the clutch again the chain wheel cover. In the aforesaid process, for that a position where the pedal interlocking shaft at one side of the bicycle joins with the chain wheel cover is provided with the one- directional axis, when power produced by the motor is greater than that produced by pedaling, the pedals become idle and thus no power is generated by the pedals. When power produced by pedaling is greater than that produced by the motor, the one-directional axis at the joined position of the pedal interlocking shaft and the chain wheel cover becomes capable of inputting power generated by pedaling toward the chain wheel cover while forcing the clutch inside the chain wheel cover to approach the center. Therefore, power generated and outputted by the motor fails to be forwarded to the chain wheel cover. Also, the one- directions is driven by the central axis of the pedal interlocking shaft to forward the power to the chain wheel cover, followed by driving chains through the gear to further rotate wheels of the bicycle, thereby accomplishing automatically switching between power generating means for power saving effects and providing enhanced usage conveniences. By applying the structure according to the invention, current transmission systems of prior bicycles can still be used while offering more power requirement options. Furthermore, not only numbers of parts can be decreased to significantly lower a volume of the power structure according to the invention when installed to a bicycle main body, but also production costs can be effectively reduced without having to greatly change current designs of the bicycle. - 5

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exploded elevational view according to the invention.

FIG. 2 shows a sectional side view according to the invention.

FIG. 3A shows an exploded elevational view of a power exchange device according to the invention.

FIG. 3B shows a planar view of a clutch according to the invention.

FIG. 4A shows a first schematic view illustrating actions of a clutch according to the invention.

FIG. 4B shows a second schematic view illustrating actions of a clutch according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To better understand the invention, detailed descriptions of a preferred embodiment shall be given with the accompanying drawings below.

Referring to FIGS. 1 and 2, an electric bicycle power structure according to the invention comprises a motor 10, a power exchange device 20 and pedal interlocking shafts 30.

The motor has an axis 11 in form of a hollow tube, which is provided with a gear at an appropriate position at a front end thereof.

Referring to FIGS. 3A and 3B, the power exchange device 20 has a planet decelerating mechanism 21, a clutch 22 and a chain wheel cover - 6 23; and is disposed at a front end of the motor 10. The gear 11a at the axis 11 of the motor 10 is pivotally disposed at a center of the planet decelerating mechanism 21, and is connected to an interior of the planet decelerating mechanism 21. The planet decelerating mechanism 21 has a protruding central gear 21a disposed at a front end thereof and also pivotally at a center of the clutch 22. The clutch 22 is installed at a center of the chain wheel cover 231; and is consisted of a triangular locating plate 22a, three planet gears 22b, and clutch plates 22c coaxial with the planet gears 22b. The clutch plates 22c can also be a formed integral with the planet gears 22b. By leaning the clutch plates 22c of the clutch 22 against an inner side of the chain wheel cover 23, and using a plurality of teeth 23a at an outer wall of the chain wheel cover 23, the power exchange device 20 can be connected to an existing transmission system of the bicycle without affecting transmission functions to further provide different power requirement options.

The pedal interlocking shaft 30 has a central axis 31, outer covers 32 at two sides thereof, and a joining cover 33. The central axis 31 is pivotally disposed at the center of the axis 11 of the motor 10. The outer cover 32 is disposed with a roller bearing 32a at an interior thereof, such that two ends of the axis 11 of the motor 10 are respectively positioned in the roller bearing 32a, while the central axis 31 of the pedal interlocking shaft 30 is inserted into the axis 11 without coming into contact with the axis 11. A position where the pedal interlocking shaft at one side of the bicycle joins with the chain wheel cover 23 is provided with the joining cover 33. The joining cover 33 is disposed with a one-directional axis 33a at an interior thereof; and has a front end thereof accommodated by an inner wall of the outer cover 31 of the pedal interlocking shaft 30, and a rear end thereof fastened in the chain wheel cover 23.

10Referring to FIGS. 3B, 4A and 4B, according to the aforesaid structure, the clutch 22 is installed at the center of the chain wheel cover 23, and is consisted of the triangular locating plate 22a, three planet gears 22b, and the clutch plates 22c coaxial with the planet gears 22b. The central gear 21a of the planet decelerating mechanism 21 is disposed at a 15central opening 22a1 of the triangular locating plate 29a in a penetrated manner, with the central gear 21a exactly and simultaneously engaged with the three planet gears 22b. In addition, each of the clutch plates 22c is interlocked with a central axis of each of the planet gears 22b.

Thus, when the central gear 21 a rotates in an anti-clockwise direction, all the three planet gears 22b at an outer periphery thereof rotate in a clockwise direction, such that the clutch plates 22c are impelled to rotate in a clockwise direction as well as forming an open status to further produce power by driving the chain wheel cover 23. Vice versa, when the chain wheel cover 23 rotates at a speed greater than that of the internal central gear 21a, the clutch plates 22c rotate in an anticlockwise direction and gather toward the center, such that the planet gears 22b are impelled to rotate in an anti-clockwise direction whereas the central gear 21 a rotates in a clockwise direction, and thus power is not transmitted to the chain wheel cover 23 as a result.

Conclusive from the above, the electric bicycle power structure according to the invention is provided with a power exchange device according to the invention and a main body according to a prior bicycle.

The invention accomplishes effects of energy saving, offering enhanced usage conveniences, and avoiding significantly modifications to prior bicycle structure for reducing production costs.

It is of course to be understood that the embodiment described herein is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

What is claimed is: 1. An electric bicycle power structure comprising a

motor, a power exchange device and pedal interlocking shafts; being capable of assisting the electric bicycle to produce power by either motor, and automatically switching between power generating means for achieving power saving effects and offering enhanced usage conveniences; and characterized that, the motor has an axis in form of a hollow tube, which is provided with a gear at an appropriate position at a front end thereof; the power exchange device has a planet decelerating mechanism, a clutch and a chain wheel cover, and is connected to an interior of the planet decelerating mechanism having a front end thereof disposed with the clutch; the gear at the axis of the motor is pivotally disposed to a center of the planet decelerating mechanism to connect with an interior of the planet decelerating mechanism; the planet decelerating mechanism has a protruding central gear disposed at a front end thereof and also pivotally at a center of the clutch; and the chain wheel cover is provided with a plurality of teeth at an outer wall thereof; and each the pedal interlocking shaft has a central axis, outer covers at - o two sides thereof, and a joining cover; the central axis is pivotally disposed at the center of the axis of the motor; the outer cover is disposed with a roller bearing at an interior thereof, such that two ends of the axis of the motor are respectively positioned in the roller bearing, while the central axis of the pedal interlocking shaft is inserted into the axis without coming into contact with the axis; a position where the pedal interlocking shaft at one side joins with the chain wheel cover is provided with the joining cover; the joining cover is disposed with a one-directional axis at an interior thereof, and has a front end thereof accommodated by an inner wall of the outer cover of the pedal interlocking shaft, and a rear end thereof fastened in the chain wheel cover.
2. The electric bicycle power structure in accordance with claim 1, wherein the clutch is installed at a center of the chain wheel cover; consisted of a triangular locating plate, three planet gears, and clutch plates coaxial with the planet gears; and can be leaned against an inner side of the chain wheel cover using the clutch plates of the clutch.
3. The electric bicycle power structure in accordance with claim 1, wherein the teeth at the chain wheel cover are joined with an existing transmission system of the bicycle without affecting transmission functions to further provide different power requirement options.
4. An electric bicycle power structure substantially as hereinbefore described with reference Lo and as shown in the accompanying drawings. l

4. The electric bicycle power structure in accordance with claim 2, wherein the clutch plates can be a formed integral with the planet gears.

5. An electric bicycle power structure substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Amendments to the claims leave been fled as follows: Claims: 1. An electric bicycle power structure comprising a motor, a power exchange device and a pedal assembly, and in which a) the motor has an output shaft in the form of a hollow tube on which a gear is mounted at a front end thereof, b) the power exchange device includes a planet decelerating mechanism, a clutch and a chain wheel cover, c) the gear on the output shaft of the motor is connected to the interior of the planet decelerating mechanism, d) the planet decelerating mechanism has a protruding central gear located centrally of the clutch which, in turn, is located centrally of the chain wheel cover, e) the chain wheel cover is provided with a plurality of external teeth, f) the pedal assembly includes a central shaft, outer covers at the two ends of the shaft and a joining cover, g) the central shaft is contained within the hollow output shaft of the motor without coming into contact with the hollow output shaft, h) each outer cover contains a roller bearing and the two ends of the output shaft of the motor are supported by the roller bearings, i) the joining cover contains a uni-directional clutch and has a front end thereof accommodated by an internal wall of the adjacent outer cover and a rear end thereof fastened in the chain wheel cover, and (w I) the clutch comprises a locating plate, planet gears that mesh with the protruding central gear of the planet decelerating mechanism and clutch plates that can be moved into contact with the inner surface of the chain wheel cover.

2. An electric bicycle power structure as claimed in Claim 1, in which the clutch locating plate is triangular and in which there are three planet gears.

3. An electric bicycle power structure as claimed in either of the preceding claims, in which the clutch plates are formed integrally with the planet gears.