Brake force regulator for a motorcycle hydraulic brake system

A brake force regulator for a motorcycle brake system comprising:

• a housing having a longitudinal stepped bore;
• a fluid inlet chamber connected to a pedal-actuated master cylinder of a rear-wheel brake circuit disposed in said bore;
• a fluid outlet chamber connected to a rear-wheel brake of said rear-wheel brake circuit disposed in said bore spaced from said inlet chamber;
• a control piston slidably sealed to said bore, said control piston having first, second and third stepped sections in that order, adjacent ends of said first and second sections being associated with said inlet chamber and adjacent ends of said second and third sections being associated with said outlet chamber, said control piston being responsive to pressure from a hand-actuated master cylinder of a front-wheel brake circuit applied to an end of said third section remote from said second section to control pressure applied to said rear-wheel brake;
• a fluid passageway disposed in said control piston interconnecting said inlet and outlet chambers;
• a closure member for said passageway disposed in said inlet chamber;
• a closure piston connected to said closure member and extending into a bore in said control piston, said closure piston being movable in the closing direction of said closure member against the force of a valve spring contained in a valve chamber at the end of said bore in said control piston, said valve chamber being connected to atmosphere;
• and
• a weak return spring disposed in said outlet chamber to urge said control piston against a stop in said bore in said inlet chamber, said control piston having a differential effective area adjacent said stop subjected to pressure in said inlet chamber in a direction opposite to the direction of the force of said return spring to cause displacement of said control piston in the direction of said outlet chamber.