GB2341364A

GB2341364A - Electrically-assisted pedal cycle

Info

Publication number: GB2341364A
Application number: GB9819561A
Authority: GB
Inventors: Jui-Lin Yang
Original assignee: ELEON SYSTEMS Inc
Current assignee: ELEON SYSTEMS Inc
Priority date: 1998-09-04
Filing date: 1998-09-09
Publication date: 2000-03-15
Also published as: GB9819561D0; DE29815923U1

Abstract

In a pedal cycle having a chain drive the tension in the chain 12 is sensed and used to control a DC electric motor assisting the pedal drive. The tension is sensed by movement of a light shielding plate 42 by the chain tension acting on a sprocket 46 against the force of a spring 44. The light shielding plate 42 has graduated levels of light permeability and its position determines the amount of light received therethrough by a sensor 49 to control the motor. The electric motor is thus controlled to provide more assistance as the chain tension increases.

Description

2341364 TITLE: ELECTRIC VEHICLE UTILIZING TENSION TO CONTROL AUXILIARY

POWER OUTPUT BACKGROUND OF THE INVENTION

(a) Field of the Invention:

The present invention relates to an electric vehicle utilizing tension to control auxiliary power output, and more particularly to an electric bicycle having a tension sensing device installed on the transmission chain of the electric vehicle.

(b) Description of the Prior Art:

Figs. 8 and 9 show a conventional auxiliary power type electric bicycle equipped with an auxiliary power device. The auxiliary power device comprises a battery jar unit 1, a revolution speed controller 2, and a DC motor 3 installed on the bicycle body. The revolution speed controller 2 is connected to a sensor 21 provided in a predetermined position of the bicycle body to detect the transmission speed of the pedals I I or transmission chain 12, so as to control the drive currents from the battery jar unit I to the DC motor 3.

The DC motor will, according to the pedaling speed of the rider, generate an auxiliary drive force in a proportional relationship. Such a structure that detects the pedaling speed to cause the DC motor 3 to output an auxiliary force is still feasible under normal road conditions; that is, when the pedaling speed increases, the output power (revolution speed) by the DC motor also speeds up.

When the bicycle goes up a slope, the pedaling speed will usually decrease and the rider will need to exert more effort. That is the time when the rider needs I the output of auxiliary power most. However, since the power output by the DC motor 3 is proportional to the pedaling speed, when the bicycle having the above-mentioned auxiliary power structure is going up a slope, it will go relatively slower and require more effort. As for why the controller is not provided on the handlebars of the bicycle to control directly the revolution speed of the DC motor 3 just like motorcycles, this is because, in many nations such as Japan and Germany, there are laws and regulations stipulating that there must be a dividing line between electric bicycles or electric tricycles and motorcycles. Those electric vehicles that make use of DC motors to provide an auxiliary power output must be driven by pedaling and must not utilize handlebars or accelerators to control the speed, so as to ensure safety of the riders.

Therefore, how to solve the above problems is the concern of the present invention. Through long-term observation and extensive research, the inventor of the present invention has found that the tension during the running process of the transmission chain is proportional to the magnitude of the pedaling drive force. In other words, the greater the pedaling drive force, the larger the tension of the transmission chain. The present invention employs a mechanical characteristic as such to develop a tension sensing device to detect the tension of the transmission chain and to control the auxiliary power output according to the magnitude of the tension.

SUNRAARY OF THE INVENTION A primary object of the present invention is, therefore, to provide an 2 electric vehicle that utilizes tension to control auxiliary power output, which can provide the required auxiliary power in a timely fashion so that the rider does not need to exert more effort when starting or going up a slope.

Another object of the present invention is to provide an electric vehicle that utilizes tension to control auxiliary power output so that it is safe to ride the electric vehicle and the control of the auxiliary power output is more precise.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present invention will be more clearly understood from the following detailed description and the accompanying drawings, in which,

Fig. 1 is a schematic view showing the use state of a preferred embodiment of the present invention; Fig. 2 is a flowchart of the control of the auxiliary power output of the 15 preferred embodiment of the present invention; Fig. 3 is a perspective structural schematic view illustrating the preferred embodiment in an installation state; Fig. 4 is a structural perspective view of the preferred embodiment of the present invention; Fig. 5 is a sectional schematic view of the structure of the preferred embodiment, illustrating the present invention before action; Fig. 6 is a sectional schematic view of the structure of the preferred embodiment, illustrating the present invention in a state of action; 3 Fig. 7 is a schematic view illustrating the state of action of the preferred embodiment of the present invention; Fig. 8 is a schematic view illustrating the use state of a prior auxiliary powered type electric vehicle; and Fig. 9 is a flowchart of the control of the prior electric vehicle of Fig. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to Figs. I to 3, the present invention basically comprises a battery jar unit I installed on an electric vehicle in an appropriate position; a revolution speed controller 2; and a DC motor 3 to provide auxiliary power.

As these structural elements are necessary in conventional electric vehicles equipped with auxiliary power devices, they will not be discussed in detail herein. The present invention is characterized in that the original transmission chain 12 of the vehicle has a tension sensing device 4 provided thereon. The device is as shown in Figs. 4 to 7, and essentially comprises a link 41, and a light shielding plate 42 connected to a bottom end of the link 4 1. In determined light shielding positions, the light shielding plate 42 is provided with gradual levels of light permeability 421 from the top to the bottom. The tension sensing device 4 further includes a lower positioning seat 43, a reset spring 44, and an upper positioning seat 45 fitted onto the link 41 in sequence. A top end of the link 41 is connected to an open slot block 47 having a sprocket wheel 46 mounted thereon. The transmission chain 12 is passed through the open slot block 47 so that it can engage the sprocket wheel 46 thereon. The link 41 and other relevant components are screwably disposed in a hollow body 4 48 having inner threads 481 at an opening end thereof by means of lower outer threads 45 1 of the upper positioning seat 45. A light cutout means 49 for coupling with the light shielding plate 42 is provided in the interior of the hollow body 48 in a predetermined position. The hollow body 48 is provided 5 with a mounting plate 482 extending from an outer edge thereof, whereby bolts 5 can be used to lock the hollow body 48 to a vehicle body 6. The abovementioned light cut-out means 49 utilizes a signal wire 491 to transmit received signals to the revolution speed controller 2 to control the output power of the DC motor 3.

With reference to Fig. 4, the interior of the hollow body 48 corresponding to the other side of the light cut-out device 49 is provided with a longitudinal guide groove 483 to position the light shielding plate 42 properly so that it will not deflect from its proper position.

Furthermore, the top end of the link 41 is secured in the open slot block 47 by means of a fastening element 411 such as a small screw.

Referring to Figs. 5 and 6, the lower outer threads 451 of the upper positioning seat 45 may be driven in and out of the inner threads 481 at the opening end of the hollow body 48, so that the light shielding plate 42 may elevate or drop with the link 41 to thereby adjust an initial position I of the light shielding plate 42, and the relative tightness of the link 4 1.

As for the gradual levels of light permeability 421 provided on the light shielding plate 42, the light permeability is higher towards the bottom end and lower towards the top end.

According to structure of the present invention as described above, when the driven sprocket wheel 46 engages the transmission chain 12 of the electric vehicle of the present invention, it can precisely detect the tension of the transmission chain 12. This is because, when the rider drives the pedals 11, the magnitude of the tension of the transmission chain 12 will change with the magnitude of the drive force, causing the driven sprocket wheel 46 and the link 41 to rise and fall therewith. When the drive force of the pedals increases, the transmission chain 12 will displace upwardly due to tautness, as shown in Figs.

6 and 7, bringing the driven sprocket wheel 46 and the link 41 connected therewith to displace upwardly as well. But since the link 41 is also connected to the light shielding plate 42 having gradual levels of light permeability 421, the light permeability rate received by the light cutout means 49 will be proportional to the elevating height of the link 41. In other words, the higher the link 41 climbs, the larger the tension of the transmission chain is. At this point, the light perineability rate will also augment. The augmentation of the light permeability rate is utilized to transmit signals to the revolution speed controller 2 to control the increase the drive electric currents from the battery jar unit I to the DC motor 3, thereby generating an auxiliary power output in a proportional relationship to provide auxiliary power to the electric vehicle of the present invention. On the contrary, when the rider stops pedaling, the transmission chain 12 will become loosened and tension is lost, so that the link 41 is reset to its initial position I due to the action of the reset spring 44, as shown in Fig. 5. The light permeability rate received by the light 6 cutout means 49 is then reduced to zero, and there is no more output of auxiliary power.

Therefore, the present invention utilizes the magnitude of the drive tension to compel the link 41 to elevate and displace to fin-ther detect the changes in the tension of the transmission chain 12 and to adjust the output power of the DC motor 3 proportionally. Compared to the prior art which utilizes transmission speed to control the output power of the DC motor 3, the present invention has the following advantages:

1. The present invention controls the output of auxiliary power based on actual needs. For instance, when the vehicle is going up a slope or being started, auxiliary power output from the DC motor 3 is needed most, and the drive tension is the largest. Then the DC motor 3 can be caused to output the greatest auxiliary power to save the rider's pedaling effort.

But if the auxiliary power output of the DC motor 3 is controlled by means of the transmission speed, the speed of the vehicle will be very slow, so that the output of auxiliary power is relatively low and cannot provide the required auxiliary power at an opportune time. Therefore, the present invention is more precise and practical compared to the prior art.

2. The present invention ensures safety of the rider during use. For instance, when the vehicle is going down a slop at a high speed, since there is no pedaling drive force, the transmission chain 12 will have no tension, then the DC motor 3 will not output any auxiliary power. On the contrary, if the output of auxiliary power is controlled by using transmission speed, the 7 fast speed of the vehicle when going down slope will increase the output of auxiliary power by the DC motor 3, which may make the bicycle travel at an excessively high speed.

Although the present invention has been illustrated and described with 5 reference to the preferred embodiment thereof, it should be understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

8

Claims

1. An electric vehicle including a transmission chain for manually driving a wheel of the vehicle, an auxiliary electrical power output arranged to drive said wheel, and a tension sensing device arranged to sense tension in said chain and to vary the output from said electrical power output in response to said sensed tension.

2. An electric vehicle according to Claim 1 wherein said auxiliary power output comprises a DC motor.

3. An electric vehicle according to Claim 2 wherein:

said tension sensing device includes a link, and a light shielding plate connected to a bottom end of said link, said light shielding plate being provided with gradual levels of light permeability from the top to the bottom in determined light shielding positions, said tension sensing device further including a lower positioning seat, a reset spring, and an upper positioning seat fitted onto said link in sequence, a top end of said link being connected to an open slot block having a sprocket wheel mounted thereon, said transmission chain being passed through said open slot block so that it can engage said driven sprocket wheel thereon, said link and other relevant components being screwably disposed in a hollow body having inner threads at an opening end thereof by means of lower outer threads of said upper positioning seat, said hollow body having a light cutout means for coupling with said light shielding plate provided in its interior in a predetermined position, said hollow body being further provided with a mounting plate extending from an outer edge thereof, whereby bolts can be used to lock said hollow body to a vehicle body of said electric vehicle, said light cutout means utilizing a signal wire to 9 transmit received signals to a revolution speed controller to control the output power of said DC motor.

4. An electric vehicle according to Claim 3 wherein the interior of 5 said hollow body corresponding to the other side of said light cutout means is provided with a longitudinal guide groove to position said light shielding plate properly so that it will not deflect from its proper position.

5. An electric vehicle substantially as herein described with reference 10 to and as illustrated in any of Figures 1 to 7 of the accompanying drawings.