Brake force regulator for a motorcycle hydraulic brake system

Claim 1

A brake force regulator for a motorcycle brake system comprising: a control piston disposed coaxially within a housing, said control piston being slidable in response to pressure from a hand master cylinder and adapted to reduce brake pressure to a rear-wheel brake upon movement of said control piston into a fluid input chamber disposed in said housing connected to a pedal master cylinder, said movement being caused by said pressure of said hand master cylinder which increases the volume of a fluid outlet chamber disposed in said housing connected to said rear-wheel brake; a fluid passageway disposed in said control piston connecting said inlet chamber to said outlet chamber; a second piston having a closure member for said passageway disposed within said control piston, said second piston being movable in a closing direction of said passageway against the force of a first spring extending into a hollow space in said housng connected to atmosphere; a return spring abuting one end of said control piston to urge said control piston into abutment with a stop in said housing adjacent said inlet chamber, said control piston having an effective area adjacent said inlet chamber subjected to pressure against the force of said return spring to cause displacement of said control piston in the direction of said outlet chamber; means disposed within said housing adjacent said control piston which, upon attainment of a predetermined differential of pressure between the pressures prevailing in said inlet and outlet chambers, open said passageway after it has been closed during a braking operation; and sealed areas of said control piston have their cross-sections dimensioned independently of each other.