ELECTRIC DRIVE FOR BICYCLES

• US 20150041234A1
• Filed: 03/25/2013
• Published: 02/12/2015
• Est. Priority Date: 04/03/2012
• Status: Active Grant

• Current Assignee: Velogical Engineering GmbH
• Original Assignee: Velogical Engineering GmbH
• Inventors: Frieden, Peter
• Granted Patent: US 9,242,698 B2
• Time in Patent Office: Days
• US Class Current: 180/220
• CPC Class Codes: B62M 13/04 with means for moving roller into driving contact with ground wheel
• CPC Class Codes: B62M 6/75 power-driven by friction rollers or gears engaging the ground wheel
• CPC Class Codes: B62M 7/12 with the engine beside or within the driven wheel

Abstract

The invention relates to an electric drive for bicycles, comprising two symmetrically arranged external-rotor type counter-rotating motors which are fed via two separate motor actuators/regulators that obtain the same control signal for power regulation purposes. The motors are mounted in an oscillating manner about an axis which is parallel, in particular substantially parallel, to the motor axis but offset with respect to the motor axis in a lateral manner, in particular in a parallel manner.

Claims

1. An electric drive for a bicycle with two symmetrically arranged counter-rotating motors of the external rotor type, which are fed by two separate motor controllers/governors which receive the same control signal for output regulation, wherein the motors are mounted to swing about an axis which is situated in parallel, in particular, essentially parallel to the motor axis, whereby the former axis is, however, laterally offset, and in particular, parallel to the motor axis, and the drive can be mounted in front of the fork or in front of the corresponding frame stay, and the connecting line between swing axis and motor axis in the working position forms an angle of less than 45°

with the wheel axis in order to generate a contact pressure F_a of the elastic ring onto the rim, with said contact pressure always being greater than the transmitted circumferential force F_u.

2. The electric drive according to claim 1 wherein an annular groove or recess for accommodating an elastic friction ring is located at or on the rotating cylindrical surface of the motors to transfer the propulsive power onto the rim by frictional contact.

4. The electric drive for a bicycle according to claim 1, wherein the maximum possible spacing between elastic friction ring and rim in the idling position is limited by a stop

5. The electric drive for a bicycle according to claim 1, wherein the rotor especially the cap of the rotor or of the motor is provided with radial air channels, which generate a stream of cooling air through the motor as a result of the centrifugal action.

6. The electric drive for a bicycle according to claim 1, wherein the winding and stator packet are impregnated or coated with a temperature-resistant plastic resin or lacquer, the ball bearings are encapsulated and the elastic ring transmitting the propulsive power consists of material resistant to abrasion, ozone and UV light.

7. The electric drive for a bicycle according to claim 1, wherein a flexible fastening system permits retrofitting on different bicycle types, with, in particular, the exact tangential alignment of the ‘

rotor being adjustable.

8. The electric drive for a bicycle according to claim 1, wherein the seating of the swing axes is integrated in the design of the forks or suspension forks or, in the case of rear-wheel drive, in the seat or chain stays and has been adjusted in the factory.

9. The electrical drive for a bicycle according to claim 1, wherein the motor housing possesses a stiff, one-sided, asymmetrical motor support as an extension arm to accommodate the swing axis, which, if necessary, is equipped with cooling fins and/or is produced as a one-piece die-cast part.

10. The electric drive for a bicycle in accordance with the preceding claims wherein the coefficient of friction is raised by the surface treatments or surface coatings of the rim flank, for example with ceramic, in order to achieve a reduction of the contact pressure and an increase in the tilt/wedge angle.

11. The electric drive for a bicycle according to claim 1, wherein the weight of the motor, when mounted on the rear wheel with a diagonal axis of swing, can be raised or balanced out by an s adjustable spring element.

12. The electric drive for a bicycle according to claim 1, wherein the swinging motion of the motor from the idling position into the working position is supported by an electromagnet with, in particular, the contact pressure of the motor onto the rim being increased.

13. The electric drive for a bicycle according to claim 1, wherein the rechargeable battery or holder thereof is fastened to the connecting points for the bottle cage.

14. The electric drive for a bicycle according to claim 1, wherein one of the two motors can be adjusted by spring tension and works permanently or intermittently as a dynamo.

3. An electric drive for a bicycle with one external rotor motor wherein an annular groove or recess for accommodating an elastic friction ring is located at or on the rotating cylindrical surface of the motor to transfer the propulsive power onto the rim by by frictional contact and the motor is mounted to swing about an axis that is parallel, in particular, essentially parallel to the motor axis, yet the axis of swing is laterally offset and, in particular, parallel to the motor axis.

15. A drive for a bicycle adapted to move in a travel direction and having a frame and a wheel rotatable about a wheel axis on the frame and having a rim and a tire on the rim, the drive comprising:

two symmetrically arranged counter-rotating motors flanking the wheel and each having an external rotor that rotates an elastic ring engageable with a respective flank of the rim about a respective motor axis;

respective mounts secured to the frame and each carrying a respective one of the motors for pivoting of the motors about swing axes spaced rearwardly in the direction from and generally parallel to the respective motor axes, each motor axis and the respective swing axis forming a plane extending at an angle of less than 45°

to the wheel axis such the ring presses against the rim with a force F_a greater than a transmitted force F_u.

16. The bicycle drive defined in claim 15, wherein the mounts and motors symmetrically flank the wheel.

17. The bicycle drive defined in claim 15, wherein each motor axis intersects the wheel axis and each rim flank is frustoconical and centered on the respective wheel axis.