Abstract: Disclosed is a master cylinder for brake systems including a cylinder body having a bore therein, a first and second piston installed in the bore to move forward and backward, and a first hydraulic pressure chamber and a second hydraulic pressure chamber, the first and second hydraulic pressure chambers being divided from each other in the bore. The master cylinder further includes a pressure regulating channel to connect the first hydraulic pressure chamber to second hydraulic pressure chamber to reduce pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber, and a flow control valve provided in the pressure regulating channel to open and close the pressure regulating channel according to the pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber.

Abstract: Disclosed is a motor driven type electric parking brake system. The parking brake system includes a drum that is rotated along with a wheel, first and second brake shoes installed in the drum to apply brake force to the drum, an operating lever that supports the two brake shoes and pushes the two brake shoes against an inner surface of the drum when a pivoting lever is pulled, a motor to generate drive power to drive the pivoting lever, a cycloid speed reducer connected to a rotating shaft of the motor to amplify the drive power, a spindle member rotatably connected to the speed reducer and having a male screw portion, and a nut member having a female screw portion reciprocally screwed to the male screw portion. The nut member is moved in a longitudinal direction of the spindle member and supports an end of the pivoting lever.

Abstract: Disclosed is a master cylinder for brake systems including a cylinder body having a bore therein, a first and second piston installed in the bore to move forward and backward, and a first hydraulic pressure chamber and a second hydraulic pressure chamber, the first and second hydraulic pressure chambers being divided from each other in the bore. The master cylinder further includes a pressure regulating channel to connect the first hydraulic pressure chamber to second hydraulic pressure chamber to reduce pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber, and a flow control valve provided in the pressure regulating channel to open and close the pressure regulating channel according to the pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber.

Abstract: Disclosed is a motor driven type electric parking brake system. The parking brake system includes a drum that is rotated along with a wheel, first and second brake shoes installed in the drum to apply brake force to the drum, an operating lever that supports the two brake shoes and pushes the two brake shoes against an inner surface of the drum when a pivoting lever is pulled, a motor to generate drive power to drive the pivoting lever, a cycloid speed reducer connected to a rotating shaft of the motor to amplify the drive power, a spindle member rotatably connected to the speed reducer and having a male screw portion, and a nut member having a female screw portion reciprocally screwed to the male screw portion. The nut member is moved in a longitudinal direction of the spindle member and supports an end of the pivoting lever.