Patent ID: 7946115

Claim:
A hydraulic cylinder for a brake caliper, comprising: a cylindrical body having a receiving space longitudinally defined therein for movably and sealingly receiving a piston, the receiving space divided into a first chamber and a second chamber diametrically smaller than the first chamber; and the piston including a closed inner chamber defined therein, the piston having a first portion and a second portion, the first portion and the second portion sealingly and movably abutted against the first chamber and the second chamber respectively, the second portion having at least one through hole defined in an outer peripheral thereof for communicating the first chamber with the closed inner chamber of the piston; a first hole and a second hole defined in the second portion for oil communicating; whereby the first portion interacts with the first chamber in a speed reduction stage, and the first portion and the second portion interact with the first chamber and the second chamber respectively in an emergency brake stage.