Master brake cylinder, braking system

A master brake cylinder for a brake system of a motor vehicle, comprising:

• a hydraulic cylinder that includes a plurality of hydraulic connections;
• a spring element;
• an elastically deformable sealing ring;
• and
• at least one hydraulic piston mounted in at least one of the hydraulic connections so as to be displaceable axially in a direction of actuation and in a relief direction, wherein:
• the hydraulic piston is displaceable in the actuation direction against a force of the spring element,
• the hydraulic piston includes at least one lateral wall opening that in at least one sliding position opens into an inner chamber of the hydraulic cylinder,
• the lateral wall opening has assigned thereto the elastically deformable sealing ring,
• an inner side of the elastically deformable sealing ring is fastened on the hydraulic piston,
• an outer side of the elastically deformable sealing ring is preloaded against the hydraulic cylinder by an inherent elasticity of the elastically deformable sealing ring,
• and the elastically deformable sealing ring is shaped such that when there is a displacement of the hydraulic piston in the actuating direction the elastically deformable sealing ring detaches from the hydraulic cylinder and when there is a displacement of the hydraulic piston in the relief direction the elastically deformable sealing ring bears on the hydraulic cylinder.

A brake system for a motor vehicle, comprising:

• at least one hydraulic circuit that has at least one hydraulically actuatable wheel brake;
• and
• a master brake cylinder that is connected to the at least one hydraulic circuit, wherein the master brake cylinder includes:
• a hydraulic cylinder that includes a plurality of hydraulic connections;
• a spring element;
• an elastically deformable sealing ring;
• and
• at least one hydraulic piston mounted in at least one of the hydraulic connections so as to be displaceable axially in a direction of actuation and in a relief direction, wherein:
• the hydraulic piston is displaceable in the actuation direction against a force of the spring element,
• the hydraulic piston includes at least one lateral wall opening that in at least one sliding position opens into an inner chamber of the hydraulic cylinder,
• the lateral wall opening has assigned thereto the elastically deformable sealing ring,
• an inner side of the elastically deformable sealing ring is fastened on the hydraulic piston,
• an outer side of the elastically deformable sealing ring is preloaded against the hydraulic cylinder by an inherent elasticity of the elastically deformable sealing ring, and
• the elastically deformable sealing ring is shaped such that when there is a displacement of the hydraulic piston in the actuating direction the elastically deformable sealing ring detaches from the hydraulic cylinder and when there is a displacement of the hydraulic piston in the relief direction the elastically deformable sealing ring bears on the hydraulic cylinder.