Propulsion unit for an electric pedal-assisted cycle and pedal-assisted cycle thereof

Patent metadata

Field	Value
Publication number	US-10766566-B2
Application number	US-201515522799-A
Country	US
Kind code	B2
Filing date	Oct 27, 2015
Priority date	Oct 31, 2014
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

Propulsion unit for an electric, pedal-assisted bicycle comprising an electric machine having a stator and a rotor, rotatable about a motor axis, said rotor being operatively connected to a crank pin, defining a crank axis, mechanically connected to pedals, and coaxial with the motor axis, wherein the rotor is coaxial and external with respect to the stator so as radially enclose the rotor. The propulsion unit comprises at least one electronic unit for operating and controlling the functioning of the electric machine, and at least a pair of housings that define a containment space which houses the electric machine and at least partially the crank pin.

First claim

The invention claimed is:

1. A propulsion unit for an electric pedal-assisted cycle (EPAC) comprising:
an electric machine having a stator and a rotor, the rotor being rotatable about a motor axis a crank pin defining a crank axis being coaxial with the motor axis,
wherein the rotor is coaxial and external to the stator, the rotor radially enclosing the stator, and
wherein the propulsion unit comprises:
at least one electronic unit for operating and controlling a functioning of the electric machine,
at least a pair of housings defining a containment space which houses the electric machine and at least partially houses the crank pin,
a transmittor of a movement from the rotor to the crank axis, the transmittor of the movement being arranged in an asymmetrical position overall and decentralised from the crank axis so as to be at least in part outside a projection of the rotor on a projection plane perpendicular to the crank axis,
the at least one electronic unit is positioned so as to fall inside a projection of the rotor on the projection plane perpendicular to the crank axis, and
the at least one electronic unit being shaped as a ‘C’ around the crank axis and being arranged to partially surround the transmittor of the movement;
wherein the transmittor of the movement comprises a first transmission stage having a first input gear, integral in rotation with the rotor and coaxial thereto, and a first output gear rotatable about a first axis parallel and offset in relation to a rotation axis;
wherein the transmittor of the movement comprises a second transmission stage having a second input gear, integral in rotation with the first output gear and coaxial therewith, and a second output gear, which meshes with the second input gear and is integral in rotation with a second shaft defining a second axis offset and parallel to the rotation axis and to the first axis.

2. The propulsion unit according to claim 1 , wherein the electronic unit is contained and is supported inside said containment space.

3. The propulsion unit according to claim 1 , wherein the electronic unit is positioned on an opposite side to the transmittor of the movement overall, in relation to the crank axis.

4. The propulsion unit according to claim 1 , wherein the propulsion unit comprises an intermediate support element contained within the containment space, wherein the intermediate support element rotatably supports the rotor and the intermediate support element supports the electronic unit in a fixed manner.

5. The propulsion unit according to claim 4 , wherein the rotor and the electronic unit are positioned on axially opposite sides in relation to said intermediate support element, along the crank axis.

6. The propulsion unit according to claim 4 , wherein the intermediate support element is arranged around the crank axis and fixed in relation to the crank axis.

7. The propulsion unit according to claim 4 , wherein the propulsion unit comprises at least one cylindrical element which mechanically connects the intermediate support element to the electronic unit, said cylindrical element being a thermal conductor for extracting heat from the electronic unit to provide heat to the intermediate support element and for extracting heat from the intermediate support element to provide heat to outside of the pair of housings.

8. The propulsion unit according to claim 7 , wherein the at least one cylindrical element is provided with an oval cross-section with respect to a cross-section plane perpendicular to a main extension axis of the at least one cylindrical element.

9. The propulsion unit according to claim 1 , wherein the electronic unit is provided with at least one electric cable and at least one corresponding conduit, the conduit being attached to the electronic unit by at least one attacher, and wherein at least one of: the conduit and an attacher of the at least one attacher is a thermal conductor in order to dissipate the heat from said electronic unit.

10. The propulsion unit according to claim 4 , wherein said first input gear is rotatably supported by the intermediate support element.

11. The propulsion unit according to claim 1 , wherein the second input gear is connected coaxially to the first output gear of the first transmission stage by a grooved profile.

12. The propulsion unit according to claim 1 , wherein said housings define seats which house support bearings for said second shaft.

13. The propulsion unit according to claim 1 , wherein the transmittor of the movement comprises a third transmission stage having a third input gear, integral in rotation with the second output gear and coaxial therewith, and a third output gear which meshes with the third input gear and which transmits the power onto the rotation axis or crank axis realizing the pedal-assist.

14. The propulsion unit according to claim 13 , wherein the propulsion unit comprises a first free wheel mounted between the third output gear and the crank pin, coaxially to the crank axis, so as to prevent the dragging of the propulsion unit when placing the crank in counter rotation or when the cycle is moving in a direction opposite to a forward direction.

15. The propulsion unit according to claim 1 , wherein the propulsion unit comprises a second free wheel mounted between the second shaft and the second output gear, so as to release a torque transmission to the second output gear to prevent a user from dragging mechanisms of the propulsion unit in rotation when the pedal-assist is not realized.

16. The propulsion unit according to claim 15 , wherein said second free wheel is configured so as to make the second output gear integral with the second shaft when a speed of rotation of a third transmission stage is greater than or equal to a speed of rotation of the second shaft.

17. The propulsion unit according to claim 15 , wherein the propulsion unit comprises at least one cylindrical element which mechanically connects an intermediate support element to the electronic unit, wherein said second free wheel is configured so that, when a speed of rotation of the second shaft is greater than a speed of the second output gear, the at least one cylindrical element disengages such that the electric machine advances using the second free wheel without requiring a rider to place the electric machine in rotation.

18. A bicycle comprising the propulsion unit according to claim 1 , wherein the crank pin is kinematically connected to a drive wheel of the bicycle.

19. The bicycle according to claim 18 , wherein a direction of advancement of the bicycle is defined, and the propulsion unit is associated and oriented in relation to a frame of the bicycle so that the electronic unit of the propulsion unit is positioned at least partially on a side of the direction of advancement of the bicycle.

Assignees

• Piaggio & C Spa

Inventors

• Capozzella Paolo
• Carmignani Luca
• Nuti Luca
• Prosperini Giorgio

Classifications

• B62M6/55 Primary

  power-driven at crank shafts parts · CPC title

• H02K9/00

  Arrangements for cooling or ventilating (channels or ducts in parts of the magnetic circuit H02K1/20, H02K1/32; channels or ducts in or between conductors H02K3/22, H02K3/24) · CPC title

• H02K11/33

  Drive circuits, e.g. power electronics (H02K11/38 takes precedence) · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title

• B62M6/45 Primary

  Control or actuating devices therefor · CPC title