Brake pressure modulator and system

Solenoid-operated modulator means for modulating the brake pressure of a motor vehicle having a master cylinder, and a plurality of wheel brake cylinders associated with the wheels, respectively, of the vehicle, comprising

• a. a valve body containing a pumping chamber and including inlet and outlet ports communicating with said pumping chamber, said inlet and outlet ports being adapted for communication with said master cylinder and with one of said wheel cylinders, respectively, said valve body also including a normally open by-pass passage directly connecting said inlet and outlet ports to by-pass said pumping chamber;
• b. first check valve means normally isolating said outlet port from said pumping chamber, and second check valve means normally isolating said pumping chamber from said inlet port;
• c. a reciprocatory pumping member extending at one end through a bore contained in said valve body and terminating in said pumping chamber;
• d. main solenoid means alternately operable between energized and de-energized conditions for reciprocating said pumping member, said main solenoid means including
• 1. a stator rigidly connected with said valve body;
• 2. a linearly movable armature connected with the other end of said pumping member for linear displacement relative to said stator between first and second end positions, thereby to effect relatively large stroke pumping operation;
• and
• 3. main spring means biasing said armature toward one of said end positions;
• e. by-pass control means for closing said by-pass passage;
• and
• f. means for alternately energizing and de-energizing said main solenoid means, thereby to reciprocate said pumping member, whereby when said by-pass passage is in the closed condition, fluid is pumped from said inlet port to said outlet port, said energizing and de-energizing means comprising
• 1. means for normally energizing said main solenoid means;
• and
• 2. switch means for de-energizing said main solenoid means when said armature is in said other end position.

In a vehicle braking system including a plurality of wheels having wheel brake cylinders, respectively, and master cylinder means for supplying fluid simultaneously to said wheel cylinders for braking the vehicle;

• the improvement which comprises
• a. at least two normally de-activated pumping means connected between said master cylinder and at least two of said wheel cylinders, respectively, each of said pumping means including
• 1. a valve body containing a pumping chamber communicating both with an inlet port connected with said master cylinder and an outlet port connected with one of the wheel cylinders, said valve body also including a normally open by-pass passage connected between said inlet and outlet ports to by-pass the pumping chamber;
• 2. first check valve means normally isolating said outlet port from said pumping chamber, and second check valve means normally isolating said pumping chamber from said inlet port;
• 3. a reciprocatory pumping member extending at one end in said pumping chamber;
• 4. main solenoid means for reciprocating said pumping member, said main solenoid means including
• a. a stator connected with the valve body;
• b. a movable armature connected with the other end of said pumping member for linear movement between first and second end positions relative to said stator;
• and
• c. main spring means biasing said armature toward one of said end positions;
• 5. by-pass control means for closing said by-pass passage;
• and
• 6. means for alternately energizing and de-energizing said solenoid means, thereby to reciprocate said pumping member, whereby when said by-pass passage is in the closed condition, fluid is pumped from said inlet port to said outlet port;
• b. wheel speed sensing means associated with at least the said two wheel cylinders;
• and
• c. speed-responsive means operable when the rotational velocity of at least one of the wheels deviates from a given value for selectively operating to the closed condition by the by-pass control means of at least one of said pumping means and for operating the main solenoid means associated therewith, thereby to pump fluid to the associated wheel cylinder to effect braking of the associated wheel.