| 摘要 |
The present invention provides a disk brake capable of ensuring excellent actuation efficiency. A piston holding mechanism 34 mounted in a disk brake 1a includes a planetary gear speed reduction mechanism 36 configured to power up a rotation of a motor 38, and a screw mechanism 52 and a ball and ramp mechanism 28 configured to convert a rotation of the planetary gear speed reduction mechanism 36 into a linear motion to advance a piston 12 in parallel. The planetary gear speed reduction mechanism 36 transmits a rotational output provided by powering up an input from the motor 38 to the screw mechanism 52 or the ball and ramp mechanism 28, and transmits a reactive force of the rotational output to the screw mechanism 52 or the ball and ramp mechanism 28. The screw mechanism 52 maintains a braked state when a supply of a rotational force from the motor 38 is stopped. As a result, it is possible to ensure excellent actuation efficiency. |
