ELECTRIC PARKING BRAKE MOTOR GEAR UNIT
id041200701000
Purpose, function
• The electric parking brake motor unit operates the built-in motor to press out the disc pads using the torque increased by the gear reduction to maintain the rear disc plates in a clamped condition. When the electric parking brake is released, the motor rotates in the opposite direction.
Construction
• The electric parking brake motor gear unit is located on the rear brake caliper.
• The electric parking brake motor gear unit has a built-in motor and a planetary gear.
Operation
When operating electric parking brake
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1. When motor operation current flows from the electronically controlled brake unit, the electric parking brake motor gear unit operates the built-in motor.
2. The motor speed/torque is transmitted to the spindle bolt by decelerating the speed using the built-in 2-step worm gear and increasing the torque.
3. When the spindle bolt rotates, the spindle nut moves to the brake piston side and it contacts the brake piston.
4. The contacted spindle nut moves the brake piston to the brake pad side and the brake piston is pressed against the brake pad.
5. The disc pads are pressed against the rear disc plates and the rear disc plates are held clamped.
When releasing electric parking brake
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1. When motor operation current flows from the electronically controlled brake unit, the electric parking brake motor gear unit operates the built-in motor.
2. The motor rotates in the opposite direction of the electric parking brake operation.
3. The motor speed/torque is transmitted to the spindle bolt by decelerating the speed using the built-in 2-step worm gear and increasing the torque.
4. When the spindle bolt rotates, the spindle nut moves to the motor side and separates from the brake piston.
5. The brake piston separates from the disc pad by the piston seal force to release the clamped condition of the rear disc plates.
