Brake for vehicle closure actuator

A power closure actuator for powering a movable closure, the power closure actuator comprising:

• an output member configured to drive movement of the movable closure;
• an electric motor coupled through at least one gear reduction stage to drive the output member;
• a shaft situated between the electric motor and the output member, the shaft configured to selectively transmit power from the electric motor to the output member;
• an integrated brake-clutch unit including a clutch and a brake device, both of which are situated along the shaft;
• and
• a hub supported on the shaft to allow relative rotation of the shaft within the hub, the hub having respective portions supporting an actuation coil of the clutch and a portion of the brake device,
• wherein the brake device includes
• an electric brake actuator operable to set a variable brake force on the shaft,
• a screw-driven thrust member movable along an axis of the shaft by the electric brake actuator,
• an axially floating rotor configured for rotation with the shaft, the axially floating rotor having a first axial side facing the screw-driven thrust member and providing a first braking surface for frictional contact therewith, and the axially floating rotor having a second axial side providing a second braking surface, and
• a passive backing brake clamp positioned adjacent the second axial side of the axially floating rotor for frictional contact with the second braking surface thereof, wherein the axially floating rotor is biased away from the passive backing brake clamp by a first biasing member,
• wherein deflection of the first biasing member coupled with axial movement of the screw-driven thrust member and the axially floating rotor is configured to enable application of the braking force by pinching action of the axially floating rotor between the screw-driven thrust member and the passive backing brake clamp.

A method of controlling a movable closure with a power closure actuator that includes an electric motor and an output member coupled to drive movement of the movable closure, the method comprising:

• moving the movable closure to an open position;
• and
• operating a brake device situated along a shaft provided in the power closure actuator between the electric motor and the output member, wherein operating the brake device includes
• energizing an electric brake actuator to move an active brake clamp along an axis of the shaft toward and into contact with an axially floating rotor configured for rotation with the shaft, and
• energizing the electric brake actuator further to move both the active brake clamp and the axially floating rotor against a bias force from a first biasing member to establish contact between the axially floating rotor and a passive backing brake clamp, the axially floating rotor being pinched between the active brake clamp and the passive backing brake clamp to apply a brake force to the axially floating rotor and with it the shaft, the brake force being applied proportional to an amount of deflection in the first biasing member.