Electric brake for vehicle
AssigneeZF Active Safety US Inc.
InventorsKraig Gerber, Galus Chelaidite
Life of this patent
Estimating the term…
Abstract
An electric brake for a wheel rotor having a brake pad includes a housing with a passage. A piston assembly in the passage includes a spindle and a piston. The spindle is rotatable to cause the piston to move axially relative to the brake pad. A drive assembly includes a motor. A gear train is connected to the motor and the spindle. A coupling mechanism is coupled to the gear train and has a first condition enabling torque transmission from the motor to the spindle to axially move the piston to apply braking force to the brake pad. The coupling mechanism has a second condition disabling torque transmission from the motor to the spindle is prevented which permits the piston to retract and reduce the braking force on the brake pad without stopping or reversing the motor.
Claims23
An electric brake for a wheel rotor having a brake pad associated therewith, comprising:
- a housing defining a passage;
- a piston assembly provided in the passage and including a spindle and a piston aligned with the brake pad, the spindle being rotatable to cause the piston to move axially relative to the brake pad;
- and
- a drive assembly comprising:
- a motor;
- a gear train for transferring torque between the motor and the spindle;
- a coupling mechanism coupled to the gear train and having a first condition locking a portion of the gear train against rotation for enabling torque transmission from the motor to the spindle for axially moving the piston to apply braking force to the brake pad, the coupling mechanism having a second condition permitting rotation of the portion of the gear train for disabling torque transmission from the motor to the spindle which permits the piston to retract and reduce the braking force on the brake pad without stopping or reversing the motor.
An electric brake for a wheel rotor having a brake pad associated therewith, comprising:
- a housing defining a passage;
- a piston assembly provided in the passage and including a spindle and a piston aligned with the brake pad, the spindle being rotatable to cause the piston to move axially relative to the brake pad;
- and
- a drive assembly comprising:
- a motor;
- planetary gear stages for connecting the motor to the spindle;
- a solenoid brake including a shaft coupled to one of the planetary gear stages and having a first condition preventing rotation of the shaft which enables torque transmission from the motor to the spindle for axially moving the piston to apply braking force to the brake pad, the solenoid brake having a second condition permitting rotation of the shaft which disables torque transmission from the motor to the spindle to permit the piston to retract and reduce the braking force on the brake pad.
A method of applying an electric brake to a wheel rotor having a brake pad, comprising the steps of:
- providing a housing having a movable piston assembly therein including a spindle and a piston aligned with the brake pad, the spindle being rotatable about an axis to cause the piston to move axially relative to the brake pad;
- rotating a motor to supply torque to the spindle through a gear train for axially moving the piston to apply braking force to the brake pad;
- and
- actuating a coupling mechanism connected to the motor and laterally offset from the axis of the spindle to enable rotation of a portion of the gear train for disabling torque transmission from the motor to the spindle which permits the piston to retract and reduce the braking force on the brake pad without stopping or reversing the motor.
Dependencies are inferred from the claim text.