Braking pressure control unit for a hydraulic brake system
AssigneeITT Industries, Inc.
InventorsBernd Schopper, Volker Berisch
Life of this patent
Estimating the term…
Abstract
Problems exist in known braking pressure control units for brake systems in which the rear wheels of a vehicle are assigned to different brake circuits. These problems include unequal outlet pressure to the two brake circuits due to manufacturing tolerances and that upon failure of one brake circuit the control function of the intact brake circuit still remains operative. According to the present invention these problems are eliminated by having two differential pistons bear against each other via a common spring device and to provide an arrangement by which upon failure of one brake circuit, the valve of the intact brake circuit will be moved into or kept in an open position.
Claims34
A braking pressure control unit for a hydraulic brake system having brakes at the wheels of one axle connected to two different brake circuits comprising:
- a casing having an intermediate piston disposed therein coaxial of a longitudinal axis, said piston being movable from its rest position in both directions relative to said casing;
- two differential pistons disposed coaxial of said axis in tandem relationship in said casing and slidable in said casing against a preloading force in opposite directions, said two differential pistons being preloaded and bearing against one another by means of a common spring device;
- a valve device having a valve seat and a valve closure member associated with each of said differential pistons and said intermediate piston, each of said valve devices having one of said valve seat and said valve closure member coupled to a different one of said differential pistons and the other of said valve seat and said valve closure member coupled to an adjacent end of said intermediate piston, each of said valve devices connecting a pressure inlet chamber of an associated one of said brake circuits to a pressure outlet chamber of said associated one of said brake circuits;
- and
- means associated with each of said differential pistons and said intermediate piston, which upon failure of one of said brake circuits, ensures that said valve device of the intact brake circuit is in its open position.
Dependencies are inferred from the claim text.