Hydraulic power supply

Claim 2

A hydraulic power supply, which comprises: a. a positive displacement hydraulic pump; b. an accumulator for the storage of pressurized hydraulic fluid, said accumulator having a supply line; c. a check valve located in said accumulator supply line to prevent the escape of pressurized fluid therefrom; d. fluid flow dividing means connected to the output of said hydraulic pump, said dividing means having a first orifice and a second orifice connected in parallel with the first orifice to permit the output from said hydraulic pump to be divided therebetween; e. pressure-sensing valve means, responsive to the pressure in said accumulator, for blocking flow from said fluid flow dividing means first orifice when the pressure in said accuMulator is above a first predetermined value and for permitting such flow when the pressure in said accumulator decreases below a second predetermined value and until such first predetermined value is reached, said pressure-sensing valve means having an input port connected to said fluid flow dividing means first orifice and an output port; and f. flow control valve means having a first input port connected to the output port of said pressure-sensing valve means and a second input port connected to said fluid flow dividing means second orifice and said flow control valve means having a first output port connected to said check valve in said accumulator supply line and a second output port for connection to a hydraulic system normally operating at low pressure, said flow control valve means being adapted, when said pressure-sensing valve means is opened to flow therethrough, to partially obstruct fluid flow into the hydraulic system normally operating at low pressure and, simultaneously with such obstruction, to allow fluid flow through said check valve and into said accumulator.

Claim 3

A hydraulic power supply in accordance with claim 1, wherein said flow control valve means comprises:

Claim 4

valve spool means movably mounted within said valve body opening for partially obstructing fluid flow from said flow control valve means first input port through said flow control valve means first output port and simultaneously for partially obstructing fluid flow from said flow control valve means second input port through said flow control valve means second output port; and

Claim 5

valve spool means movably mounted within said valve body opening for partially obstructing fluid flow from said flow control valve means first input port through said flow control valve means first output port and simultaneously for partially obstructing fluid flow from said flow control valve means second input port through said flow control valve means second output port; and

Claim 6

valve spool means movably mounted within said valve body for opening and closing flow from said pressure-sensing valve input port through said pressure-sensing valve output port, said valve spool means in operation being responsive to the pressure at the pressure-sensing port to produce a force on said valve spool means urging it to a position to close flow; and

Claim 7

valve spool means movably mounted within said valve body for opening and closing flow from said pressure-sensing valve input port through said pressure-sensing valve output port, said valve spool means in operation being responsive to the pressure at the pressure-sensing port to produce a force on said valve spool means urging it to a position to close flow; and

Claim 8

valve spool means movably mounted within said valve body for opening and closing flow from said pressure-sensing valve input port through said pressure sensing valve output porT, said valve spool means in operation being responsive to the pressure at the pressure-sensing port to produce a force on said valve spool means urging it toward a position to close flow; and

Claim 9

valve spool means movably mounted within said valve body for opening and closing flow from said pressure-sensing valve input port through said pressure sensing valve output porT, said valve spool means in operation being responsive to the pressure at the pressure-sensing port to produce a force on said valve spool means urging it toward a position to close flow; and

Claim 10

resilient means for urging said valve spool means toward a position to open flow from said pressure-sensing valve input port through said pressure-sensing valve output port.

Claim 11

resilient means for urging said valve spool means toward a position to open flow from said pressure-sensing valve input port through said pressure-sensing valve output port.

Claim 12

resilient means for urging said valve spool means toward a position to open flow from said pressure-sensing valve input port through said pressure-sensing valve output port.

Claim 13

resilient means for urging said valve spool means toward a position to open flow from said pressure-sensing valve input port through said pressure-sensing valve output port.

Claim 14

resilient means for urging said valve spool means toward a position for substantially complete blockage of flow from said flow control valve means first input port through said flow control means first output port and toward a position for full flow from said flow control valve means second input port through said flow control valve means second output port.

Claim 15

resilient means for urging said valve spool means toward a position for substantially complete blockage of flow from said flow control valve means first input port through said flow control means first output port and toward a position for full flow from said flow control valve means second input port through said flow control valve means second output port.

Claim 16

A hydraulic power supply in accordance with claim 2, wherein said pressure-sensing valve means comprises:

Claim 17

A hydraulic power supply in accordance with claim 3, wherein said fluid flow dividing means comprises an orifice plate having a first and a second orifice therein located in the path of the output flow from said power-steering pump, in operation, to permit the flow from said power-steering pump to be divided between said orifices.

Claim 18

A hydraulic power supply in accordance with claim 1, wherein said pressure-sensing valve means comprises:

Claim 19

A common hydraulic power supply for a power-steering system and a power brake system which comprises: a. a hydraulic pump of the positive displacement type; b. an accumulator for the storage of pressurized hydraulic fluid, said accumulator having a supply line; c. a check valve located in said accumulator supply line to prevent the escape of pressurized fluid therefrom; d. fluid flow dividing means connected to the output of said hydraulic pump, said dividing means having a first orifice and a second orifice connected in parallel with said first orifice to permit the output from said hydraulic pump to be divided therebetween; e. a pressure-sensing valve comprising a valve body having an opening therein and input, output, exhaust and pressure-sensing ports communicating with the opening, the opening being generally cylindrical in shape but larger in diameter at one portion than at another, the pressure-sensing port communicating with the opening at its larger diameter portion; an open center spool mounted for axial movement within said valve body opening, said open center spool having a large diameter cylindrical portion corresponding to the large diameter cylindrical portion of the opening and a small diameter cylindrical portion corresponding to the small diameter cylindrical opening, the small diameter portion being spaced from the large diameter portion of the spool to provide a central opening therebetween, said spool having a first position wherein said valve body output port is connected through said valve spool central region to said valve body exhaust port and wherein flow from said valve body input port to said valve body output port is blocked by said valve spool and wherein fluid entering said valve body through the pressure-sensing port exerts an axial force on the large diameter cylindrical portion of said valve spool to urge it toward its first position, and said valve spool having a second position wherein said valve body exhaust port is blocked and said valve body input port is open for flow therefrom through said valve body output port; and resilient means for urging said valve spool toward its second position; and f. a flow control valve comprising a valve body having an opening therein and first input and output ports and second input and output ports communicating with the opening, the opening having at least one cylindrical portion, said valve body first input port being connected to said pressure-sensing valve output port, said valve body first output port being connected to said check valve in said accumulator supply line, said valve body second input port being connected to said fluid flow dividing means second orifice, said valve body second output port being connected to the power-steering system; a valve spool having at least one cylindrical portion corresponding to that of said valve body opening, said valve spool being axially movable within said valve body opening, the length of said valve spool cylindrical portion being sufficiently small to prevent complete blockage of said valve body first and second output ports but sufficiently large to permit partial blockage of said valve body first and second output ports; and resilient means for urging said valve spool toward a position to block flow from said first input port through said first output port; and whereby said hydraulic pump may continuously supply hydraulic fluid to the power steering system, and whereby, when the pressure in said accumulator is above a first predetermined value, said valve spool of said pressure-sensing valve is in its first position to obstruct floW from said pressure-sensing valve output port so that substantially all of the output from said hydraulic pump flows through the power-steering system, and whereby, when the pressure in said accumulator decreases below a second predetermined value, said pressure-sensing valve spool is in its second position to permit flow from said pressure-sensing valve input port through said pressure-sensing valve output port to said flow control valve first input port and through said flow control valve first output port through said check valve and into said accumulator, until the pressure in said accumulator again reaches the first predetermined value.

Claim 20

A common hydraulic power supply for a power-steering system and a power brake system which comprises: a. a hydraulic pump of the positive displacement type; b. an accumulator for the storage of pressurized hydraulic fluid, said accumulator having a supply line; c. a check valve located in said accumulator supply line to prevent the escape of pressurized fluid therefrom; d. fluid flow dividing means connected to the output of said hydraulic pump, said dividing means having a first orifice and a second orifice connected in parallel with said first orifice to permit the output from said hydraulic pump to be divided therebetween; e. a pressure-sensing valve comprising a valve body having an opening therein and input, output, exhaust and pressure-sensing ports communicating with the opening, the opening being generally cylindrical in shape but larger in diameter at one portion than at another, the pressure-sensing port communicating with the opening at its larger diameter portion; an open center spool mounted for axial movement within said valve body opening, said open center spool having a large diameter cylindrical portion corresponding to the large diameter cylindrical portion of the opening and a small diameter cylindrical portion corresponding to the small diameter cylindrical opening, the small diameter portion being spaced from the large diameter portion of the spool to provide a central opening therebetween, said spool having a first position wherein said valve body output port is connected through said valve spool central region to said valve body exhaust port and wherein flow from said valve body input port to said valve body output port is blocked by said valve spool and wherein fluid entering said valve body through the pressure-sensing port exerts an axial force on the large diameter cylindrical portion of said valve spool to urge it toward its first position, and said valve spool having a second position wherein said valve body exhaust port is blocked and said valve body input port is open for flow therefrom through said valve body output port; and resilient means for urging said valve spool toward its second position; and f. a flow control valve comprising a valve body having an opening therein and first input and output ports and second input and output ports communicating with the opening, the opening having at least one cylindrical portion, said valve body first input port being connected to said pressure-sensing valve output port, said valve body first output port being connected to said check valve in said accumulator supply line, said valve body second input port being connected to said fluid flow dividing means second orifice, said valve body second output port being connected to the power-steering system; a valve spool having at least one cylindrical portion corresponding to that of said valve body opening, said valve spool being axially movable within said valve body opening, the length of said valve spool cylindrical portion being sufficiently small to prevent complete blockage of said valve body first and second output ports but sufficiently large to permit partial blockage of said valve body first and second output ports; and resilient means for urging said valve spool toward a position to block flow from said first input port through said first output port; and whereby said hydraulic pump may continuously supply hydraulic fluid to the power steering system, and whereby, when the pressure in said accumulator is above a first predetermined value, said valve spool of said pressure-sensing valve is in its first position to obstruct floW from said pressure-sensing valve output port so that substantially all of the output from said hydraulic pump flows through the power-steering system, and whereby, when the pressure in said accumulator decreases below a second predetermined value, said pressure-sensing valve spool is in its second position to permit flow from said pressure-sensing valve input port through said pressure-sensing valve output port to said flow control valve first input port and through said flow control valve first output port through said check valve and into said accumulator, until the pressure in said accumulator again reaches the first predetermined value.