Pressure damping device for brake system

1. 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 vehicle 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 a main oil passage 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;

first and second pistons that are spaced apart from each other and move forward and backward within the housing;

a spring that is interposed between the first and second pistons to provide an elastic force to the first and second pistons, wherein a sealing member is provided on an outer circumferential surface of each piston so that a space between the first and second pistons is sealed, and an air damping space whose volume is changed in accordance with a pressure of a liquid pressure is provided between the first and second pistons; and

a damping member provided in the first and second pistons so as to be brought into contact with the lid member and the other side of the housing, respectively, and covering each of the first and second pistons.

2. The pressure damping device according to claim 1 , wherein the damping member is spaced apart from the outer circumferential surface of each piston by a predetermined interval so as to form an auxiliary damping space.

3. The pressure damping device according to claim 1 , wherein the damping member is made of a rubber material.

4. The pressure damping device according to claim 1 , wherein the first and second pistons include a spring insertion groove formed on surfaces thereof facing each other so that the spring is inserted into the spring insertion groove.

5. The pressure damping device according to claim 1 , wherein a stopper portion protruding toward the piston is formed on the other side of the housing so that movement of the first and second pistons provided within the housing is restricted.

6. The pressure damping device according to claim 5 , wherein any one of the first and second liquid pressure holes is formed on a side surface of the stopper portion, and the remaining liquid pressure hole is formed on one side outer circumferential surface of the housing.

7. 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 vehicle 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 a main oil passage 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;

first and second pistons that are spaced apart from each other and move forward and backward within the housing; and

a spring that is interposed between the first and second pistons to provide an elastic force to the first and second pistons, wherein a sealing member is provided on an outer circumferential surface of each piston so that a space between the first and second pistons is sealed, and an air damping space whose volume is changed in accordance with a pressure of a liquid pressure is provided between the first and second pistons,

wherein the first and second pistons include a spring insertion groove formed on surfaces thereof facing each other so that the spring is inserted into the spring insertion groove.

8. 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 vehicle 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 a main oil passage 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;

first and second pistons that are spaced apart from each other and move forward and backward within the housing; and

a spring that is interposed between the first and second pistons to provide an elastic force to the first and second pistons, wherein a sealing member is provided on an outer circumferential surface of each piston so that a space between the first and second pistons is sealed, and an air damping space whose volume is changed in accordance with a pressure of a liquid pressure is provided between the first and second pistons,

wherein a stopper portion protruding toward the piston is formed on the other side of the housing so that movement of the first and second pistons provided within the housing is restricted.

9. The pressure damping device according to claim 8 , wherein any one of the first and second liquid pressure holes is formed on a side surface of the stopper portion, and the remaining liquid pressure hole is formed on one side outer circumferential surface of the housing.