Patent ID: 7926625

Claim:
A disk braking device comprising: a disk plate fixed to a wheel; a pad unit arranged to generate a frictional force between the pad unit and the disk plate, the pad unit including at least a first pad unit portion and a second pad unit portion; a piston mechanism arranged to move the pad unit into pressure contact with the disk plate, the piston mechanism including at least a first piston portion including at least one piston and a second piston portion including at least one piston, and all of the pistons have a same cylinder area; and a caliper body arranged to hold the piston mechanism; wherein each of the first and second pad unit portions includes: a single base plate, the at least one piston of the first piston portion arranged to abut the single base plate of the first pad unit portion and the at least one piston of the second piston portion arranged to abut the single base plate of the second pad unit portion; and at least one friction member attached to the single base plate and arranged to abut against the disk plate, and all of the friction members have a same friction member area; the first pad unit portion has a total friction member area corresponding to a total cylinder area of the first piston portion, and the second pad unit portion has a total friction member area corresponding to a total cylinder area of the second piston portion; the first piston portion includes fewer pistons than the second piston portion such that the total cylinder area of the first piston portion is less than the total cylinder area of the second piston portion, and the total friction member area of the first pad unit portion is less than the total friction member area of the second pad unit portion; and the single base plate of the first pad unit portion is not connected to the single base plate of the second pad unit portion such that the single base plate of the first pad unit portion acts independently of the single base plate of the second pad unit portion.