Electric disk brake
AssigneeHitachi, Ltd.
InventorTohma Yamaguchi
Life of this patent
Estimating the term…
Abstract
An electric disk brake that prevents uneven abrasion of a disk rotor when the brake is not in operation. Rotation of an electric motor is slowed down by a differential speed reducing mechanism, and is converted to linear motion of a piston by a ball ramp mechanism. When the brake is not in operation, the piston is retracted by reverse rotation of the electric motor so that a predetermined pad clearance is maintained. When the brake is not in operation, a pad-retracting-control electric current is supplied to the electric motor so that the piston is biased backward while being maintained in one position. When the brake is not in operation, contact of the disk rotor with the brake pads due to runout of the disk rotor triggers smooth retracting of the piston, thereby preventing uneven abrasion of the disk rotor.
Claims13
An electric disk brake, comprising:
- an electric motor;
- a rotation-linear motion converting mechanism for converting a rotational movement of the electric motor into a linear movement;
- a pad pressing member for pressing a brake pad against a disk rotor by the linear movement of the rotation-linear motion converting mechanism;
- and
- a controller for, when the brake is in operation, supplying an electric current to the electric motor so as to generate a target thrust force of the pad pressing member,
- wherein the pad pressing member, after returning to a predetermined position, is maintained in the position even though the controller stops supplying an electric current to the electric motor;
- and
- when the brake is not in operation, the controller supplies a predetermined pad-retracting-control electric current to the electric motor so that the pad pressing member is urged backward while being maintained in the position, whereby
- when the disk rotor contacts the brake pad, retracting of the brake pad is initiated, and
- when the disk rotor does not contact the brake pad, the position of the brake pad is maintained.
An electric disk brake, comprising:
- an electric motor;
- a rotation-linear motion converting mechanism for converting a rotational movement of the electric motor into a linear movement;
- a pad pressing member for pressing a brake pad against a disk rotor by the linear movement of the rotation-linear motion converting mechanism;
- a position detector for detecting a rotational position of the electric motor;
- and
- a controller for supplying an electric current to the electric motor so as to generate a target thrust force of the pad pressing member,
- the controller, when the brake is not in operation, returning the pad pressing member to a predetermined position and maintaining the pad pressing member in the position, and supplying to the electric motor a pad-retracting-control electric current that is a lowest electric current allowing the pad pressing member to be maintained in the predetermined position.
Dependencies are inferred from the claim text.