Electromechanical brake actuator and cam disc

A cam disc (108, 108′, 108″, 208, 308, 408) for a brake actuator (102, 202, 302, 402), the cam disc being configured to be connected to a driveshaft of an electric motor (106, 206),

• wherein the cam disc (108, 108′, 108″, 208, 308, 408) has a contact surface configured to bear against a contact surface of a brake plunger (114, 214, 314) for directly transmitting a driving torque between the cam disc (108, 108′, 108″, 208, 308, 408) and the brake plunger (114, 214, 314) in such a way that the contact surfaces slide or roll on each other,
• wherein the contact surface of the cam disc (108, 108′, 108″, 208, 308, 408) extends about a pivot point D at a radial distance r defined as a function r(φ) with a rate of change r′(φ) dependent on the angular position φ of the cam disc (108, 108′, 108″, 208, 308, 408), and the contact surface is configured to effect a non-linear transfer between the driving torque of the cam disc (108, 108′, 108″, 208, 308, 408) and the force transmitted to the brake plunger (114, 214, 314),
• wherein the radial distance r(φ) is at a minimum at an angular position where φ=φmin and is at a maximum at an angular position where φ=φmax,
• wherein the rate of change r′(φ) is positive at least in certain regions in a first angular range φmin≤φ≤φmax and the rate of change r′(φ) is negative at least in certain regions in a second angular range φmax≤φ≤360°,
• wherein, in the first angular range φmin≤φ≤φmax, the function r(φ) has a first function profile r1(φ), and, in the second angular range φmax≤φ≤360°, has a second function profile r2(φ) which differs from r1(φ).

An electromechanical brake actuator (102, 202, 302, 402) for a brake, in particular a commercial vehicle disc brake, having:

• an electric motor (106, 206) for generating a driving torque,
• a cam disc (108, 108′, 108″, 208, 308, 408) which is rotatably mounted and operatively connected to the electric motor (106, 206), and
• a brake plunger (114, 214, 314) configured to move along a plunger axis, for actuating a brake lever (358) of the brake (368),
• wherein the cam disc (108, 108′, 108″, 208, 308, 408) and the brake plunger (114, 214, 314) have contact surfaces which bear against each other and slide or roll on each other for directly transmitting the driving torque from the cam disc (108, 108′, 108″, 208, 308, 408) to the brake plunger (114, 214, 314),
• wherein the contact surface of the cam disc (108, 108′, 108″, 208, 308, 408) extends about a pivot point D at a radial distance r defined as a function r(φ) with a rate of change r′(φ) and dependent on an angular position φ of the cam disc (108, 108′, 108″, 208, 308, 408), and
• wherein the contact surface is configured in such a way that there is a non-linear transfer between the driving torque of the cam disc (108, 108′, 108″, 208, 308, 408) and the force transmitted to the brake plunger (114, 214, 314), wherein the radial distance r(φ) is at its minimum for an angular position where φ=φmin and is at its maximum for an angular position where φ=φmax·,
• wherein the rate of change r′(φ) is positive at least in certain regions in a first angular range φmin≤φ≤φmax, and in that the rate of change r′(φ) is negative at least in certain regions in a second angular range φmax≤φ≤360°,
• wherein the function r(φ) has a transition function r3(φ) which meets the first function profile r1(φ) at a first angular position φ1,3, wherein r1′(φ1,3)=r3′(φ1,3), and which meets the second function profile r2(φ) at an angular position φ3,2, wherein r2′(φ3,2)=r3′(φ3,2).