An internal shoe drum brake has a body (1) carrying a plurality of circumferentially spaced friction elements (2) movable into engagement with a rotatable drum (3) by a hydraulic system including an actuator (5) having a pressure-applying cylinder (2) in which a pressure-generating piston (21) is driven by an electrical stepper motor (28), slave cylinders (4) which actuate the friction elements, and internal ducts (7, 8) for transmitting pressure from piston (21) to slave cylinders (4).

A disk brake having an electromagnetic friction clutch that can be brought into controllable frictional engagement with a brake disk. The friction clutch can act on a device for generating hydraulic pressure independent of the direction of rotation, and this pressure can act upon a clamping device for operating friction linings. To press the friction linings against the brake disk, energy is taken from the rotating vehicle wheel by means of the friction clutch and metered to the clamping device with pressure fluid as the energy carrier. The friction brake can be used in passenger cars, for example.

An automatically acting braking system for a stepper motor (10) of the type having a rotor (18) that is radially centered within a stationary stator (12) and which rotates about the central axis of a central shaft (30). The rotor (18) is allowed to axially slide back and forth, biased in one direction continually by a resilient means (40). When the stator (12) is energized, it pulls the rotor (18) to an axially centered position within stator (12), but when it is de energized, the resilient means (40) pushes the rotor (18) to one side, lockingly engaging its teeth (24) with the teeth (44) of a fixed locking ring (42).

An apparatus for braking a rotating member having an engaged state and a disengaged state is disclosed. Rotation of the rotating member is inhibited by the apparatus when the apparatus is in the engaged state. The braking apparatus includes a housing, an actuator, and a first brake structure. The first brake structure includes a brake pad having a contact surface. The brake structure is pivotally connected to the housing and further connected to the actuator. The actuator is operable to cause pivotal motion of the brake structure, thereby causing arcuate motion of the contact surface toward the rotating member. The frictional force between the rotating member and the contact surface causes further arcuate motion of the contact surface toward the rotating member and places the apparatus in the engaged state.

A wheel cylinder is formed in the brake caliper for each wheel of a vehicle and brake fluid is supplied from a master cylinder to this wheel cylinder by way of a fluid passage. A brake piston is provided inside the wheel cylinder and includes a piezoelectric piston device inside. By the application of voltage, this piezoelectric piston device expands and contracts the brake piston. A control valve is provided in the fluid passage to open and close it to selectively partition off the master cylinder. When the control valve has closed the passage, a voltage is applied to the piezoelectric piston device to expand it and control the pressure acting on the brake piston in the wheel cylinder to vary the braking force.