The invention relates to a
parking brake cylinder and a
brake caliper unit. The
parking brake cylinder includes: an intermediate body; a
brake cylinder body, which forms a
brake cylinder chamber with the intermediate body; and a brake
piston, which is arranged in the brake cylinder chamber The parking cylinder body forms a parking cylinder cavity with the intermediate body, and at least two sealed cavities are arranged in the parking cylinder body, and each sealing cavity is connected to each other; the force transmission unit includes: a force transmission component, which is placed in the parking cylinder cavity, and the force transmission component Including the parking screw, the parking nut set outside the parking screw and the
ratchet set on the other end of the parking screw; at least two
dowel rods are arranged symmetrically in a circle, one end of the
dowel rod is connected to the brake
piston, and the other end passes through the The intermediate body is connected to the parking nut; the compression spring is set on the
dowel rod, and is located between the intermediate body and the parking nut; multiple parking pistons are installed on the parking nut in a circumferential symmetry, and each parking
piston corresponds to a sealed cavity Setting; relief device, cooperate with
ratchet. The invention has high safety, long service life and low use cost.