Valve for fluid-actuated brake system

Claim 2

In a valve having first and second separated chambers which are selectively communicatable and wherein said first chamber is for high-pressure fluid which is to flow into said second chamber, a pair of relatively movable members forming an elongated passage of nonuniform cross-sectional area extending between said chambers and having closely spaced wall means and wider spaced wall means which are spaced apart in all relatively moved positions thereof and which closely spaced wall means will apply frictional forces to fluid flowIng through said passage sufficiently to reduce the velocity of said fluid, a seal member carried by one of said members and engageable with the other one of said members at one end of said passage for closing the passage and said closely spaced wall means and said wider spaced wall means forming an elongated passage of substantially uniform cross-sectional area when the valve is fully open.

Claim 3

The structure according to claim 1 wherein said relatively movable members are a cylinder and a piston and said passage is formed by grooves in the adjacent surfaces of said cylinder and piston.

Claim 4

The structure according to claim 2 wherein said seal member is mounted on said piston and located in said first chamber and further including a retainer sleeve on said piston extending about said seal member.

Claim 5

The structure according to claim 3 wherein said retainer sleeve has a radially inwardly directed flange engaged with said seal and capable of applying a pulling force thereto on movement of said piston relative to said cylinder so as to open said passage.

Claim 6

A valve for a vehicle brake system, said valve comprising a hollow housing, relatively moveable piston and cylinder means in said housing defining therewith an inlet chamber for supply fluid under pressure and an outlet chamber for braking fluid, said cylinder means extending about said piston means and cooperating therewith to form an elongated passage extending between said inlet and outlet chambers in all relatively moved positions of said piston and cylinder means, seal means on said piston means engaged with said cylinder means in one position of said piston means so as to close said passage, said passage being shaped so that in said one position of said piston means said passage has narrow sections and wider sections of predetermined lengths arranged in an alternating relation, said narrow section applying sufficient frictional force to the fluid flowing therethrough to reduce the velocity of said fluid and means extending into said housing and operable to move said piston means in a direction away from said one position, said piston means being operable in response to movement in said direction to disengage said seal means from said cylinder means to communicate said inlet and outlet chambers and progressively decrease the lengths of said narrow passage sections and increase the lengths of said wider sections whereby said frictional forces are proportionately reduced and movement of said piston means to open the valve fully results in all of said passage sections being substantially the same width.

Claim 7

A valve for a vehicle brake system, said valve comprising a hollow housing, relatively moveable piston and cylinder means in said housing defining therewith an inlet chamber for supply fluid under pressure and an outlet chamber for braking fluid, said cylinder means extending about said piston means and cooperating therewith to form an elongated passage extending between said inlet and outlet chambers in all relatively moved positions of said piston and cylinder means, seal means on said piston means engaged with said cylinder means in one position of said piston means so as to close said passage, said passage being shaped so that in said one position of said piston means said passage has narrow sections and wider sections of predetermined lengths arranged in an alternating relation, said narrow section applying sufficient frictional force to the fluid flowing therethrough to reduce the velocity of said fluid and means extending into said housing and operable to move said piston means in a direction away from said one position, said piston means being operable in response to movement in said direction to disengage said seal means from said cylinder means to communicate said inlet and outlet chambers and progressively decrease the lengths of said narrow passage sections and increase the lengths of said wider sections whereby said frictional forces are proportionately reduced and movement of said piston means to open the valve fully results in all of said passage sections being substantially the same width.

Claim 8

A valve according to claim 5 wherein said passage is formed by coacting grooved surfaces on said piston and cylinder means arranged in a closely spaced relation, said surfaces having spaced grooves formed therein which are in substantial radial alignment in said one position of said piston means.

Claim 9

A valve according to claim 6 wherein said grooves are of substantially equal size.

Claim 10

A valve according to claim 5 wherein said seal means is a ring-shape body of resilient material extending about said piston means and located in said inlet chamber at one end of said passage, and further including a retainer ring extending about said body so as to clamp said body between said ring and said piston means.

Claim 11

A valve according to claim 8 wherein said ring has a flange engaged with said seal body and operable on movement of said piston means in said one direction to apply a pulling force on said seal body directed away from said passage.