US 8,944,103 B2 · Meterless hydraulic system having displacement control valve

Abstract

A hydraulic system is disclosed. The hydraulic system may have a pump, a tank, a displacement actuator having first and second chambers, a regeneration valve, and a load-holding valve. The hydraulic system may also have a displacement control valve including a valve element, and a stationary cage portion at least partially forming a high-pressure passage fluidly connecting the pump and valve element, a low-pressure passage fluidly connecting the valve element and tank, a first displacement actuator passage fluidly connecting the valve element and first chamber, a second displacement actuator passage fluidly connecting the valve element and second chamber, a load-holding control passage fluidly connecting the valve element and load-holding valve, and a regeneration control passage fluidly connecting the valve element and regeneration valve. The displacement control valve may also include a movable cage portion that is movable to selectively restrict fluid flow through only the first and second displacement actuator passages.

Claims18

Dependent claims

A displacement control valve, comprising:

a valve element;
a stationary cage portion surrounding the valve element and at least partially forming:
a high-pressure passage;
a low-pressure passage;
a first displacement actuator passage;
a second displacement actuator passage;
and
at least one control valve passage;
and
a movable cage portion disposed proximate the stationary cage portion and being movable to selectively restrict only the first and second displacement actuator passages;
and
wherein the at least one control valve passage includes:
a regeneration control passage;
and
a load-holding control passage;
and
wherein the valve element is movable between:
a first position at which the first and second displacement actuator passages are simultaneously exposed to substantially similar fluid pressures;
a second position at which the first displacement actuator passage is fluidly connected with the high-pressure passage and the second displacement actuator passage is fluidly connected with the low-pressure passage;
and
a third position at which the second displacement actuator passage is fluidly connected with the high-pressure passage and the first displacement actuator passage is fluidly connected with the low-pressure passage.

18 more elements

A hydraulic system, comprising:

a pump;
a tank;
a displacement actuator having a first chamber and a second chamber;
a regeneration valve;
a load-holding valve;
and
a displacement control valve, the displacement control valve including:
a valve element;
a stationary cage portion surrounding the valve element and at least partially forming:
a high-pressure passage fluidly connecting the pump with the valve element;
a low-pressure passage fluidly connecting the valve element with the tank;
a first displacement actuator passage fluidly connecting the valve element with the first chamber of the displacement actuator;
a second displacement actuator passage fluidly connecting the valve element with the second chamber of the displacement actuator;
a load-holding control passage fluidly connecting the valve element with the load-holding valve;
and
a regeneration control passage fluidly connecting the valve element with the regeneration valve;
and
a movable cage portion disposed proximate the stationary cage portion and being movable to selectively restrict only the first and second displacement actuator passages.

15 more elements

A hydraulic system, comprising:

a primary pump;
a displacement actuator associated with the primary pump and having first and second chambers;
a hydraulic actuator;
first and second actuator passages connecting the primary pump with the hydraulic actuator in closed loop manner;
a regeneration valve disposed within a passage connecting the first and second actuator passages;
first and second load-holding valves associated with the first and second actuator passages, respectively;
a charge pump;
a tank;
a displacement control valve including:
a valve element movable between:
a first position at which the first and second chambers of the displacement actuator and the regeneration valve are simultaneously fluidly connected to both the charge pump and the tank in a restricted manner, and flow from the first and second load-holding valves to the tank is blocked;
a second position at which the first chamber of the displacement actuator is fluidly connected with the charge pump, and the second chamber of the displacement actuator, the regeneration valve, and the first and second load-holding valves are fluidly connected with the tank;
and
a third position at which the second chamber of the displacement actuator and the regeneration valve are fluidly communicated with the charge pump and the first chamber of the displacement actuator and the first and second load-holding valves are fluidly communicated with the tank;
a stationary cage portion surrounding the valve element;
and
a movable cage portion disposed proximate the stationary cage portion and being movable to selectively restrict fluid flow between the valve element and the displacement actuator;
a link connected between the movable cage portion and the displacement actuator, the link being configured to transfer motion of the displacement actuator to the movable cage portion;
an operator interface device configured to receive input regarding desired movement of the hydraulic actuator;
and
a controller in communication with the operator interface device and the displacement control valve, the controller being configured to control movement of the valve element between the first, second, and third positions based on the input.

18 more elements

Dependencies are inferred from the claim text.

Meterless hydraulic system having displacement control valve

Life of this patent

Meterless hydraulic system having displacement control valve

Life of this patent

Abstract

Claims18