| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance a response of a liquid pressure type disc brake equipped with a parking brake mechanism. <P>SOLUTION: When a parking brake operates, a sun gear 44 of a planetary gear mechanism 31 is rotated by an electric motor 30, and a spur gear speed reduction mechanism 32 is rotated by the rotation of a planetary carrier 48. A ball-ramp mechanism 13 advances a piston 10 for braking. Here, the rotation of a ring gear 46 of the planetary gear mechanism makes a ratchet lever 58 engaged with a ratchet tooth 51A of the planetary carrier 48, so that the planetary carrier 48 is fixed to hold a braking state. At releasing the parking brake, the inverse rotation of the electric motor 30 rotates the ring gear 46 so that the ratchet lever 58 is disengaged from the ratchet tooth 51A, thus resulting in the rotation of the planetary carrier 48 to release braking. Since no conventional worm gear is used, a load on the electric motor 30 is small, and high in responsiveness. <P>COPYRIGHT: (C)2012,JPO&INPIT |
