Abstract: A piston boot has an annular fixing part that is formed on one end side of a stretchable part and abuts against an inner peripheral side of the cylinder. An outer peripheral surface of the annular fixing part is provided with a first region that abuts against an inner peripheral surface of the cylinder and a second region that is disposed closer to a bottom side of the cylinder than the first region in a piston axial direction. The outer diameter of the first region is larger than the inner diameter of the region of the inner peripheral surface of the cylinder that faces the second region.

Abstract: A piston boot has an annular fixing part that is formed on one end side of a stretchable part and abuts against an inner peripheral side of the cylinder. An outer peripheral surface of the annular fixing part is provided with a first region that abuts against an inner peripheral surface of the cylinder and a second region that is disposed closer to a bottom side of the cylinder than the first region in a piston axial direction. The outer diameter of the first region is larger than the inner diameter of the region of the inner peripheral surface of the cylinder that faces the second region.

Abstract: A disk brake capable of improving work efficiency when a friction pad is attached to a mount member. Ear portions of a friction pad are inserted in pad guides of a mount member. A side push spring, which pushes the friction pad in a rotational direction of the disk, is provided at the friction pad. A pad spring is disposed between the mount member and the friction pad. The pad spring includes a guide plate portion and a guide protruding portion. The guide plate portion is attached so as to be able to abut against the pad guide of the mount member, and functions to guide the friction pad in an axial direction of the disk. The guide protruding portion extends from an outer-side portion of this guide plate portion toward an outer side in the disk axial direction. The guide protruding portion is inclined in the disk rotational direction.

Abstract: A disk brake capable of improving work efficiency when a friction pad is attached to a mount member. Ear portions of a friction pad are inserted in pad guides of a mount member. A side push spring, which pushes the friction pad in a rotational direction of the disk, is provided at the friction pad. A pad spring is disposed between the mount member and the friction pad. The pad spring includes a guide plate portion and a guide protruding portion. The guide plate portion is attached so as to be able to abut against the pad guide of the mount member, and functions to guide the friction pad in an axial direction of the disk. The guide protruding portion extends from an outer-side portion of this guide plate portion toward an outer side in the disk axial direction. The guide protruding portion is inclined in the disk rotational direction.

Abstract: A return spring is provided between a friction pad and a mount member. The return spring biases the friction pad in a return direction for separating the friction pad from the disk, and is made of a metallic plate. The return spring includes a fixation portion on a proximal end side thereof, and the fixation portion is fixed to an ear portion of a back plate of the friction pad. The return spring includes an abutment portion, and the abutment portion is in elastic abutment with an abutment plate portion of a pad spring, which corresponds to a mount member side, on an outer side in a disk radial direction relative to the fixation portion. The pad spring includes a guide portion extending in a disk axial direction and supporting a side surface of an intermediate portion of the return spring.

Abstract: A return spring is provided between a friction pad and a mount member. The return spring biases the friction pad in a return direction for separating the friction pad from the disk, and is made of a metallic plate. The return spring includes a fixation portion on a proximal end side thereof, and the fixation portion is fixed to an ear portion of a back plate of the friction pad. The return spring includes an abutment portion, and the abutment portion is in elastic abutment with an abutment plate portion of a pad spring, which corresponds to a mount member side, on an outer side in a disk radial direction relative to the fixation portion. The pad spring includes a guide portion extending in a disk axial direction and supporting a side surface of an intermediate portion of the return spring.