1. Field of the Invention
The invention relates to an improved wheel brake for a motor vehicle.
2. Description of the Prior Art
In the field of passenger cars and motorbikes, hydraulic wheel brakes, often in the form of disk brakes, are usual today. Hydraulic means that the wheel brakes have a hydraulic actuating device with a piston-cylinder unit, with which a friction brake lining can be pressed for braking against a brake body that is connected to a vehicle wheel in a manner fixed against relative rotation. The brake body, in the case of a disk brake, is a brake disk. Hydraulic wheel brakes are familiar to one skilled in the art and therefore need not be described in further detail here.
In utility vehicles, such as trucks, compressed-air-actuated (pneumatic) wheel brakes are employed. These too are familiar to one skilled in the art and need not be described in detail here. Both hydraulic and compressed-air-actuated wheel brakes can be described by the term “pressure-fluid-actuated wheel brakes”.
Recently, developments have been made in electromechanical wheel brakes, that is, wheel brakes that have an electromechanical actuating device. One example of this is disclosed by International Patent Application WO 96/03301. This known electromechanical wheel brake has an electric motor and a spindle drive as a rotation-to-translation conversion gear; connected between the electric motor and the spindle drive is a planetary gear, as a step-down gear. The spindle drive converts a rotating driving motion of the electric motor into a translational motion for pressing a friction brake lining against a brake body. The electric motor, the rotation-to-translation conversion gear, and if present the step-down gear form the electromechanical actuating device of the wheel brake.
The known pressure-fluid-actuated and electromechanical wheel brakes may in principle be embodied not only as disk brakes but also as drum brakes or in any arbitrary other form of brake construction.