Disclosed is a disk type parking brake employing a ball-in-ramp type actuator. The parking brake improves a structure of a sealing member installed around a shaft between a caliper housing and a lever member to enhance the braking performance.
1. A parking brake, comprising:
a disk rotated together with a wheel of a vehicle;
inner and outer disk pads reciprocating in a carrier coupled to a body of the vehicle and attached to inner and outer peripheral surfaces of the disk;
a caliper housing slidably installed in the carrier to operate the outer disk pad and provided therein with a piston which reciprocates to operate the inner disk pad;
an actuator installed within the caliper housing to operate the piston and having a shaft protruding to a rear side of the caliper housing through a rear hole formed at the rear side of the caliper housing;
a lever member coupled to the shaft outside the caliper housing to connect the actuator to a parking cable; and
a sealing member installed around the shaft between the caliper housing and the lever member,
wherein the sealing member integrally includes a housing coupling portion coupled to an inner periphery of the rear hole, a support rib supported by an outer surface of the caliper housing around the rear hole, a shaft support portion attached to a surface of the shaft between the caliper housing and the lever member, a connecting portion having a spacing groove for spacing the connecting portion from the shaft, and a lever member support portion adhering to a surface of the lever member and having a first resilient force guide groove formed on a contact surface of the lever member support portion such that the lever member support portion resiliently supports the surface of the lever member.
2. The parking brake of claim 1 , wherein the actuator includes a fixed ramp plate fixedly installed in a chamber formed within the caliper housing and having a plurality of ramps, a rotary ramp plate having a plurality of ramps corresponding to the ramps of the fixed ramp plate and rotated through the shaft by the lever member, a plurality of balls provided among the ramps and moving the rotary ramp plate forward during rotation of the rotary ramp plate, and a push rod pushed during the forward movement of the rotary ramp plate to push the piston.
3. The parking brake of claim 2 , wherein the sealing member further includes the connecting portion connecting the shaft support portion and the lever member support portion while being spaced apart from the shaft.
4. The parking brake of claim 1 , wherein a second resilient force guide groove is formed on a contact portion of the shaft support portion such that the shaft support portion resiliently support the surface of the shaft.
5. The parking brake of claim 2 , wherein a grease filling groove for filling grease is formed on the contact surface of the lever member support portion making contact with the surface of the lever member.