Pressure limited flow priority boost

Patent metadata

Field	Value
Publication number	US-9810334-B2
Application number	US-201414765139-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Jan 31, 2013
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A hydraulic valve assembly includes an inlet; an outlet; a pressure compensator upstream of the inlet; and a pressure limited flow priority boost valve spool movable between a first position and a second position and comprising an outer spool body and an inner spool body. The outer spool body includes deadhead meter notches disposed such that, in the first position, the spool closes fluid communication between the inlet and the pressure compensator, and such that, in the second position, the spool opens fluid communication between the inlet and the pressure compensator. The inner spool body is movable relative to the outer spool body and is configured to open fluid communication between the inlet and the outlet so as to bypass the compensator. The flow between the inlet and the compensator is a reduced pilot flow.

First claim

What is claimed is:

1. A pressure limited flow priority boost valve comprising:
an inlet chamber;
a metering chamber;
a spool bore fluidly connected between the inlet chamber and the metering chamber;
a feed chamber opening to two longitudinally spaced locations of the spool bore;
a compensator that fluidly couples the metering chamber to the feed chamber;
a first workport chamber that fluidly couples a first workport to the spool bore; and
a spool disposed in the spool bore and moveable from a neutral position to a first workport position,
wherein the spool includes:
an outer spool body having a first longitudinal side and a second longitudinal side, the first longitudinal side having a longitudinal bore and at least one radial bore in fluid communication with the longitudinal bore;
an inner spool body disposed in the longitudinal bore and axially movable with respect to the outer spool body, the inner spool body being biased toward the second side, wherein a metering chamber bypass is formed in the longitudinal bore of the outer spool body between an exterior peripheral surface of the inner spool body and an interior peripheral surface of the outer spool body, the inner spool body including at least one longitudinal bore and at least one radial bore in fluid communication with the longitudinal bore of the inner spool body and the radial bore of the outer spool body,
wherein, when the spool is in the neutral position, the metering chamber bypass is blocked and the inlet chamber is disconnected from the metering chamber, the feed chamber, and the first workport chamber, and
wherein, when the spool is in the first workport position, (i) the inlet is fluidly connected to the metering chamber via a first fluid passageway, and the metering chamber bypass forms a second fluid passageway that fluidly connects the inlet to the workport chamber while bypassing the metering chamber and the compensator if a pressure at the workport chamber is below a predetermined value, and (ii) the inlet is disconnected from the workport chamber via the metering chamber bypass if the pressure at the workport chamber is above a predetermined value.

2. The pressure limited flow priority boost valve of claim 1 , wherein the first fluid passageway accommodates a reduced pilot flow between the inlet chamber and the metering chamber.

3. The pressure limited flow priority boost valve of claim 1 , wherein, when the spool is in the first workport position, the inlet is fluidly connected to the metering chamber via one or more notches.

4. The pressure limited flow priority boost valve of claim 1 , further comprising a second workport chamber,
wherein the spool is moveable from a neutral position to a second workport position, and
wherein when the spool is in the second workport position, the inlet is fluidly connected to the metering chamber via one or more maximum flow recesses.

5. The pressure limited flow priority boost valve of claim 1 , wherein the second fluid passageway which bypasses the metering chamber accommodates a greater flow than the first fluid passageway between the inlet chamber and the metering chamber.

6. The pressure limited flow priority boost valve of claim 1 , wherein the spool includes a pilot relief valve disposed at a first end of the outer spool body and in fluid communication with the longitudinal bore of the outer spool body.

7. The pressure limited flow priority boost valve of claim 1 , wherein the outer spool body includes deadhead meter notches on a radially outward and longitudinally central portion for providing a load sense signal and a reduced pilot flow.

8. A hydraulic valve assembly comprising:
the pressure limited flow priority boost valve of claim 7 ;
an inlet;
an outlet;
the spool of the pressure limited flow priority boost valve disposed between the inlet and the outlet; and
the compensator of the pressure limited flow priority boost valve disposed downstream of the deadhead meter notches.

9. A hydraulic valve assembly comprising:
an inlet;
an outlet;
a pressure compensator downstream of the inlet; and
a pressure limited flow priority boost valve spool movable between a neutral position and a working position and comprising an outer spool body and an inner spool body,
wherein the outer spool body includes deadhead meter notches disposed such that, in the neutral position, the pressure limited flow priority boost valve spool closes fluid communication between the inlet and the pressure compensator, and such that, in the working position, the pressure limited flow priority boost valve spool opens a first fluid passageway to allow fluid communication between the inlet and the pressure compensator, and
wherein, in the working position, the inner spool body is movable relative to the outer spool body and is configured to form a second fluid passageway between the inlet and the outlet that bypasses the pressure compensator when a pressure at the outlet is below a predetermined value, wherein the second fluid passageway is blocked when the pressure limited flow priority boost valve spool is in the neutral position.

10. The hydraulic valve assembly of claim 9 comprising:
the pressure limited flow priority boost valve spool disposed between the inlet and the outlet; and
the pressure compensator being disposed downstream of the deadhead meter notches.

11. A pressure limited flow priority boost valve spool comprising:
an outer spool body having a first longitudinal side and a second longitudinal side, the first longitudinal side having a longitudinal bore and at least one radial bore in fluid communication with the longitudinal bore; and
an inner spool body disposed in the longitudinal bore and axially movable with respect to the outer spool body, the inner spool body being biased toward the second side, wherein a metering chamber bypass is formed in the longitudinal bore of the outer spool body between an exterior peripheral surface of the inner spool body and an interior peripheral surface of the outer spool body, the inner spool body including at least one longitudinal bore and at least one radial bore in fluid communication with the longitudinal bore of the inner spool body and the radial bore of the outer spool body,
wherein the outer spool body includes deadhead meter notches on a radially outward and longitudinally central portion for providing a load sense signal and a reduced pilot flow,
wherein when the outer spool body is in a neutral position, the metering chamber bypass is blocked, and
wherein when the outer spool body is shifted from the neutral position, the inner spool body is movable relative to the outer spool body to allow the metering chamber bypass to open fluid communication between an inlet and an outlet so as to bypass a compensator disposed downstream from the inlet when a pressure at the outlet is below a predetermined value.

12. The valve spool of claim 11 , further comprising:
a pilot relief valve disposed at a first end of the outer spool body and in fluid communication with the longitudinal bore of the outer spool body.

13. The valve spool of claim 11 , wherein the inner valve spool is configured to provide a priority boost flow when the pressure at the outlet is below the predetermined value.

14. The valve spool of claim 11 , wherein the outer spool body includes one or more maximum flow recesses on the longitudinally central portion,
wherein the deadhead meter notches are longitudinally spaced from the recesses towards the first longitudinal side.

15. A hydraulic valve assembly comprising:
the pressure limited flow priority boost valve of clai

Assignees

• Parker Hannifin Corp

Inventors

• Coolidge Gregory T

Classifications

• F15B13/0418

  Load sensing elements sliding within a hollow main valve spool · CPC title

• F16K3/029

  with two or more gates · CPC title

• F15B11/042 Primary

  by means in the feed line {, i.e. "meter in"}(F15B11/046, F15B11/05 take precedence) · CPC title

• F16K31/12

  actuated by fluid ({fluid-actuated lift valves F16K1/126} ; fluid-actuated check valves F16K15/00; fluid-actuated safety valves F16K17/00) · CPC title

• F16K17/18 Primary

  opening on surplus pressure on either side · CPC title