Master cylinder low/high pressure combination valve which operates independently of brake pedal position
AssigneeAlfred Teves GmbH
InventorJoachim Maas
Life of this patent
Estimating the term…
Abstract
A brake pressure control device (1) is described in which a low-pressure valve (19) and a high-pressure valve (29) are both actuatable by a brake pedal, resulting in a brake circuit (36) being connectible alternatively either to a reservoir (23) or to a pressure source (33, 34) by releasing or depressing the brake pedal. In order to allow control of the brake pressure by an electronic control, a valve piston (17) operating the high and low pressure valves (19, 29) is movable by an electromagnet (15) independently of the actuating position of the brake pedal, into a position in which the brake circuit (36) is connected to the reservoir (23) and the connection to the pressure source (33, 34) is closed.
Claims12
A brake pressure control for a brake circuit of a hydraulic vehicle brake system comprising:
- a housing;
- a high pressure valve and a low pressure valve combination disposed in said housing;
- an actuator rod adapted to be advanced by a brake pedal from a rest position;
- an actuator piston slidably mounted in said housing adapted to be engaged at one end by said actuator rod to be advanced in an actuation direction;
- a hydraulic fluid outlet connected to said brake circuit;
- an unpressurized reservoir;
- a pressure source;
- said high pressure valve when opened connecting said fluid outlet to said pressure source;
- said low pressure valve when open connecting said unpressurized reservoir to said hydraulic fluid outlet;
- a valve piston, and means carrying said valve piston within said actuator piston as said actuator piston is advanced by said actuator rod, said means allowing relative movement of said valve piston in said actuator piston in a direction opposite to said actuation direction of movement of said actuator piston upon application of a predetermined force to said valve piston;
- means causing said low pressure valve to be closed and said high pressure valve to be successively opened as said valve piston moves with said actuator piston in said actuation direction;
- electromagnetic means energizable to exert a force on said valve piston effective to move said valve piston within said actuator piston independently of the actuating position of said actuator rod to open said low pressure valve and cause said hydraulic fluid outlet to be connected to said reservoir.
A brake pressure control device in combination with an automotive hydraulic braking system including at least one wheel brake, a pressure source, an unpressurized reservoir, an actuator rod movable from a rest position to actuate said brake system, said brake pressure control device including:
- a high pressure valve and means connecting said pressure source with said wheel brake when said high pressure valve is opened;
- a low pressure valve and means connecting said reservoir with said wheel brake when said low pressure valve is opened;
- manual operator means operatively associated with said actuator rod and said high pressure valve and said low pressure valve including means causing said high pressure valve to be closed and said low pressure valve to be opened with said actuator rod in said rest position, said manual operating means causing said low pressure valve to be closed and thereafter said high pressure valve to be opened as said actuator rod is advanced from said rest position to cause wheel brake actuation;
- and,
- controllably operated means causing said high pressure valve to be closed and said low pressure valve to be opened notwithstanding the position of said actuator rod, whereby said brake is controllably released regardless of the position of said actuator rod.
Dependencies are inferred from the claim text.