Electric assist device for a bicycle
AssigneeMavic Group
InventorJean-Pierre Mercat
Life of this patent
Estimating the term…
Abstract
An electric assist device for a bicycle comprising a shaft coupled in rotation with a pair of cranks and being able to be rotated in a positive direction by an electric motor, a connection mechanism being placed between the motor and the shaft, which connection mechanism has at least three distinct states. The states includes State 1, termed assist state, in which the motor transmits a torque to the shaft via a drive part which rotates at the same speed as the shaft, State 2, termed freewheel state, in which the rotation of the shaft in the positive direction is greater than that of the drive part, and State 3, termed disconnection state, in which a rotation in the positive direction or in the negative direction of the shaft cannot cause the motor to rotate.
Claims17
An electric assist device for a bicycle comprising:
- a shaft secured in rotation with a pair of cranks and configured to be driven in rotation in a positive direction by an electric motor;
- and
- a connection mechanism between the motor and the shaft, the connection mechanism comprising either a declutchable freewheel or a freewheel and a clutch so that the connection mechanism has at least three distinct states:
- state 1, called assist state, in which the motor transmits a torque to the shaft via a driving piece which turns at a same speed as the shaft,
- state 2, called free-wheel state, in which the rotation of the shaft in the positive direction is greater than that of the driving piece, and
- state 3, called disconnection state, in which a rotation in the positive direction of the shaft cannot drive the rotation of the motor and a rotation in a negative direction of the shaft cannot drive the rotation of the motor.
An electric assist method for a bicycle equipped with a device that includes
- a shaft secured in rotation with a pair of cranks and configured to be driven in rotation in a positive direction by an electric motor, and
- a connection mechanism between the motor and the shaft, the connection mechanism comprising either a declutchable freewheel or a freewheel and a clutch so that the connection mechanism has at least three distinct states:
- state 1, called assist state, in which the motor transmits a torque to the shaft via a driving piece which turns at a same speed as the shaft,
- state 2, called free-wheel state, in which the rotation of the shaft in the positive direction is greater than that of the driving piece, and
- state 3, called disconnection state, in which a rotation in the positive direction of the shaft cannot drive the rotation of the motor and a rotation in a negative direction of the shaft cannot drive the rotation of the motor, the electric assist method comprising:
- controlling, by a microcontroller, the rotation of the motor in a first direction, called positive direction, when assistance is desired by a user, said positive direction being such that it generates a forward motion of the bicycle, and, when a speed of rotation of the cranks is zero or when the cranks turn in the direction opposite to the forward motion of the bicycle, controlling the rotation of the motor in the direction opposite the first direction, for a short time period.
Dependencies are inferred from the claim text.