Solenoid operated fluid flow control valves
AssigneeLucas Industries public limited company
InventorJohn P. Bayliss
Life of this patent
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Abstract
A solenoid-operated fluid-flow control valve comprising a single solenoid coil, the energization of which controls the movement of first and second armatures which in turn control first and second respective valve members. The armatures are biased away from the solenoid by respective springs, one of which is weaker than the other. When the solenoid is energized by a constant current the armature with the weaker spring is attracted to the end of the solenoid and forms part of a magnetic circuit. This increases the magnetic flux at the other end of the solenoid, allowing the second armature to be drawn to the solenoid sequentially after, and subsequent to, the drawing-in the of the first armature. Particular anti-lock brake systems incorporating the valve are disclosed.
Claims16
A solenoid-operated fluid-flow control valve comprising a single solenoid coil having opposed first and second ends, first and second valve means provided in the control valve and first and second armatures associated respectively with said first and second ends of said coil and associated respectively with said first and second valve means, wherein energisation of said solenoid coil at a substantially constant energy level controls movement of said armatures to operate said first and second valves sequentially said solenoid coil having a central core with a central core passage and said first valve means is provided at one end of said core passage and comprises a valve member on said first armature which co-operates with a valve seating on said core and said second valve means is at or adjacent the other end of said core passage, means defining a variable restrictor operable in response to movement of said first valve member relative to said valve seating, and means defining a fixed fluid restrictor acting in series with said variable restrictor.
A hydraulic anti-skid braking system for vehicles comprising a brake-applying master cylinder in fluid communication with brake applying means via a cut-off valve, said cut-off valve having an open condition in which brake-applying fluid pressure can be transmitted from said master cylinder to said brake-applying means and a closed condition in which said brake-applying means is isolated from the hydraulic pressure in said master cylinder, means for producing a skid signal, an expander piston movable in a bore between an advanced position in which said cut-off valve is in its open condition and a retracted position in which said cut-off valve is in its closed condition, an expansion chamber of variable volume in fluid communication with said brake-applying means and having a smaller volume when said expander piston is in its advanced position and a larger volume when said expander piston is in its retracted position, a support chamber defined in part by the part of said bore into which said piston retracts and being in fluid communication with means for supplying pressurised hydraulic fluid via a first fluid pathway, the hydraulic pressure in said support chamber determining the position of said expander piston, and a second fluid pathway being provided from said support chamber to a reservoir of hydraulic fluid, wherein a solenoid-operated fluid flow control valve is provided, said control valve comprising a single solenoid coil having opposed first and second ends, first and second valve means provided in the control valve, and first and second armatures associated respectively with said first and second ends of said coil and associated respectively with said first and second valve means, wherein energisation of said solenoid coil at a substantially constant energy level controlling movement of said armatures to operate said first and second valves sequentially, said first valve means being provided in said first fluid pathway and being operable upon energisation of said solenoid in response to a skid signal to isolate said support chamber from said means for supplying pressurised hydraulic fluid, and said second valve means being provided in said second fluid pathway and being operable upon energisation of said solenoid to open communication between said support chamber and said reservoir in response to a skid signal to dump said hydraulic fluid from said support chamber whereafter said support piston retracts to cause said cut-off valve to isolate said brake-applying means from said master cylinder and to relieve hydraulic pressure in said brake-applying means, said second valve means being arranged to operate sequentially after said first valve means operates.
An anti-skid braking system for vehicles in which hydraulic braking pressure applied to brake-applying means is relieved subsequent to the production of a skid signal and is applied at a later time, the system comprising a brake-applying master cylinder in fluid communication with brake-applying means via a cut-off valve, said cut-off valve having an open condition in which brake-applying fluid pressure is transmitted from said master cylinder to said brake-applying means and a closed condition in which there is no direct communication between said master cylinder and said brake-applying means, means for providing a skid signal, brake re-applying re-application means operated in response to a skid signal, a dump fluid passageway leading from said brake-applying means and provided with a dump valve, and a brake re-applying passageway communicating the output of said re-application means to said brake-applying means via a flow control valve, wherein a solenoid operated fluid-flow control valve is provided, said control valve comprising a single solenoid coil having opposed first and second ends, first and second valve means provided in the control valve, and first and second armatures associated respectively with said first and second ends of said coil and associated respectively with said first and second valve means, wherein energisation of said solenoid coil at a substantially constant energy level controlling movement of said armatures to operate said first and second valves sequentially, said first valve means is said cut-off valve and comprises a valve member provided on said first armature which co-operates with a seating at one end of a central core passage provided in a central core of the solenoid, and said dump valve comprises said second valve means and is provided at the other end of said core passage, said cut-off valve being adapted to isolate said brake-applying means from said master cylinder upon energisation of said solenoid in response to a skid signal sequentially before said dump valve opens to relieve the hydraulic pressure in said brake-applying means.
A solenoid-operated fluid-flow control valve comprising a single solenoid coil, inlet and outlet valve seatings, valve means provided in said control valve for co-operation with said seatings, at least one armature associated with said valve means, wherein energisation of said solenoid coil controls movement of said armature to operate said valve means, said solenoid coil having a central core with a central core L passage and at least one of said valve seatings is located at one end of said core, means defininnga variable restrictor operable in response to operation of said valve means, and means defining a fixed fluid restrictor acting in series with said variable restrictor.
Dependencies are inferred from the claim text.