Power steering control valve

An apparatus for use in a vehicle to control operation of a power steering motor, said apparatus comprising:

• first and second valve members which are rotatable relative to each other to control fluid flow to and from the power steering motor;
• and
• damping means for damping relative movement between said first and second valve members, said damping means including a plurality of surface means rotatable with said first valve member for at least partially defining a plurality of chambers which hold fluid and a plurality of pistons rotatable with said second valve member, said plurality of pistons and surface means being movable relative to each other to contract first and second chambers of said plurality of chambers and force fluid to flow from said first and second chambers and to expand third and fourth chambers of said plurality of chambers and to enable fluid to flow into said third and fourth chambers upon relative rotation between said first and second valve members in a first direction, said plurality of pistons and surface means being movable relative to each other to expand said first and second chambers and enable fluid to flow into said first and second chambers and contract said third and fourth chambers and to force fluid to flow from said third and fourth chambers upon relative rotation between said first and second members in a second direction opposite to said first direction;
• each of said chambers being connected in fluid communication with a flow of fluid from the power steering motor through a restrictor, said plurality of pistons and surface means being movable relative to each other upon relative rotation between said first and second valve members in the first direction to induce a flow of fluid from the first and second chambers through first and second restrictors into the flow of fluid from the power steering motor and to induce a flow of fluid from the flow of fluid from the power steering motor through third and fourth restrictors into the third and fourth chambers, said plurality of pistons and surface means being movable relative to each other upon relative rotation between said first and second valve members in the second direction to induce a flow of fluid from the flow of fluid from the power steering motor through said first and second restrictors into the first and second chambers and to induce a flow of fluid from the third and fourth chambers through said third and fourth restrictors into the flow of fluid from the power steering motor.

An apparatus for use in a vehicle to control operation of a power steering motor, said apparatus comprising:

• first and second valve members which are rotatable relative to each other about an axis of rotation to control fluid flow to and from the power steering motor, said first valve member having first and second arcuate grooves which open toward said second valve member and have a center of curvature disposed on the axis of rotation of said first and second valve members;
• first and second pistons connected with said second valve member, said first piston extending from said second valve member into said first arcuate groove in said first valve member, said second piston extending from said second valve member into said second arcuate groove in said first valve member, said first piston cooperating with said first arcuate groove in said first valve member to at least partially define first and second chambers disposed on opposite sides of said first piston, said second piston cooperating with said second arcuate groove in said first valve member to at least partially define third and fourth chambers on opposite sides of said second piston;
• a first restrictor connected with said first valve member to restrict fluid flow to and from said first chamber;
• a second restrictor connected with said first valve member to restrict fluid flow to and from said second chamber;
• a third restrictor connected with said first valve member to restrict fluid flow to and from said third chamber;
• a fourth restrictor connected with said first valve member to restrict fluid flow to and from said fourth chamber;
• said first piston and groove being movable relative to each other to induce a flow of fluid from said first chamber through said first restrictor and to induce a flow of fluid to said second chamber through said second restrictor upon relative rotation between said first and second valve members in a first direction, said first piston and groove being movable relative to each other to induce a flow of fluid from said second chamber through said second restrictor and to induce a flow of fluid to said first chamber through said first restrictor upon relative rotation between said first and second valve member in a second direction opposite said first direction;
• said second piston and groove being movable relative to each other to induce a flow of fluid from said third chamber through said third restrictor and to induce a flow of fluid to said fourth chamber through said fourth restrictor upon relative rotation between said first and second valve members in said first direction, said second piston and groove being movable relative to each other to induce a flow of fluid from said fourth chamber through said fourth restrictor and to induce a flow of fluid to said third chamber through said third restrictor upon relative rotation between said first and second valve members in said second direction.