Brake master cylinder for a motor vehicle brake system with profiled pressure piston

The invention relates to a brake master cylinder arrangement for a motor vehicle brake system comprising: a brake master cylinder housing (12) with a cylindrical recess (14), at least one pressure piston (16, 18) moveable in the cylindrical recess (14) of the brake master cylinder housing (12) along a longitudinal axis (A) and guided in a sealing manner; and a fluid reservoir for storing brake fluid which is fluidically connected via a fluid channel (44) to the brake master cylinder housing (12). The at least one pressure piston (16, 18) together with the brake master cylinder housing (12) encloses a pressure chamber (56, 58) in a sealing manner, which chamber is or can be fluidically connected to a fluid circuit of the motor vehicle brake system and, depending on the position of the associated pressure piston (16, 18), is fluidically connected to the fluid reservoir or disconnected therefrom. A sealing arrangement (46, 48) enclosing the pressure piston (16, 18) is provided between the outer circumferential surface (60, 62) of the pressure piston (16, 18) and the cylindrical recess (14) of the brake master cylinder housing (12). In order to improve the response behaviour of the motor vehicle brake system, according to the invention, in an axial region that axially spans the sealing arrangement (46, 48) in a starting position of the pressure piston (16, 18), the outer circumferential surface (62) of the pressure piston (16, 18) is furnished with profiling (64, 66) that provides a fluidic connection between the fluid reservoir and the pressure chamber (56, 58).