Patent ID: 8875741

Claim:
A pressure damping device for a brake system that is provided in an oil passage of a hydraulic block so as to connect first and second hydraulic circuits for respectively controlling a liquid pressure transmitted to two wheels, the pressure damping device comprising: a cylindrical housing that is fixed to the oil passage, includes a first liquid pressure hole and a second liquid pressure hole respectively communicating with main oil passages of the first and second hydraulic circuits, and is opened on one side thereof; a lid member that is coupled so as to close the opened one side of the housing; a first piston that includes a flange portion in contact with an inner circumferential surface of the housing and a pressing portion extending from a center of the flange portion to one side of the housing, and moves forward and backward within the housing; a second piston that includes a flange portion in contact with the inner circumferential surface of the housing and a pressing portion extending from the center of the flange portion to the other side of the housing, and moves forward and backward within the housing, the second piston being spaced apart from the first piston by a predetermined interval; a spring that is interposed between the first and second pistons to provide an elastic force to the first and second pistons; and a damping member that is provided so as to surround an outer circumferential surface of the pressing portion of each of the first and second pistons, wherein an air damping space whose volume is changed in accordance with a pressure of the liquid pressure when a space between the first and second pistons is sealed is formed between the first and second pistons.