초록 ▼

A sequential stepped directional control valve accepts pressurized hydraulic fluid from a pressure port, and directs that pressurized fluid to a first stage port, or to both a first stage port and a second stage port. In the neutral position, the valve blocks the flow of pressurized hydraulic fluid

A sequential stepped directional control valve accepts pressurized hydraulic fluid from a pressure port, and directs that pressurized fluid to a first stage port, or to both a first stage port and a second stage port. In the neutral position, the valve blocks the flow of pressurized hydraulic fluid into the valve. In the first stage position, pressurized hydraulic fluid flows into the valve and is directed by the valve to the first stage port, however, the pressurized fluid flow to the second stage port is blocked. In the second stage position, pressurized hydraulic fluid flows into the valve and is directed to both the first and second stage ports. When the valve transitions from the first stage position to the second stage position, the valve does not cycle through a neutral position, and the flow of pressurized hydraulic fluid to the first stage port is uninterrupted.

대표청구항 ▼

1. A sequential stepped directional control valve having at least three operating positions, in which one of the operating positions is a neutral position, comprising: (A) a hollow cage having an axial direction and a radial direction, the cage being pierced by a cage pressure port, by a cage first

1. A sequential stepped directional control valve having at least three operating positions, in which one of the operating positions is a neutral position, comprising: (A) a hollow cage having an axial direction and a radial direction, the cage being pierced by a cage pressure port, by a cage first stage port, by a cage second stage port, and by a cage pump port, and the cage having a hollow cage central passage;(B) a spool adapted to fit snugly within the cage in which location the spool is moveable relative to the cage in a direction substantially parallel to the axial direction of the cage;(C) a solenoid coil substantially annularly surrounding a pole piece adapted to produce a magnetic force in response to an electrical current applied to the solenoid coil;(D) a magnetically responsive plunger attached to the spool, the plunger being magnetically responsive to the magnetic force produced by the pole piece;(E) one or more springs within the sequential stepped directional control valve directly or indirectly biasing the spool;(F) wherein (1) when no electrical current is applied to the solenoid coil, the springs within the sequential stepped directional control valve directly or indirectly bias the spool such that the spool is located in the neutral position; (2) when a first predetermined electrical current is applied to the solenoid coil, the magnetic force produced in the pole piece acts upon the plunger to counteract the biasing caused by the springs directly or indirectly upon the spool so as to cause the plunger to move to a position within the sequential stepped directional control valve such that the spool attached to the plunger is located in a first stage operating position different from the neutral position; and (3) when a second predetermined electrical current is applied to the solenoid coil, the magnetic force produced in the pole piece acts upon the plunger to counteract the biasing caused by the springs directly or indirectly upon the spool so as to cause the plunger to move to a position within the sequential stepped directional control valve such that the spool attached to the plunger is located in a second stage operating position different from the neutral position and different from the first stage operating position; and(G) wherein (1) when the spool is in the neutral position, the spool acts to block hydraulic fluid under pressure from entering the cage central passage of the sequential stepped directional control valve through the cage pressure port, the spool allows hydraulic fluid to flow through the cage first stage port into the sequential stepped directional control valve and the spool directs the hydraulic fluid entering the cage first stage port into the sequential stepped directional control valve to flow out of the sequential stepped directional control valve through the tank port, and the spool allows hydraulic fluid to flow through the cage second stage port into the sequential stepped directional control valve and the spool directs hydraulic fluid entering the second stage port into the sequential stepped directional control valve to flow out of the sequential stepped directional control valve through the tank port; (2) when the spool is in the first stage operating position, the spool allows hydraulic fluid under pressure to flow through the cage pressure port into the sequential stepped directional control valve and the spool directs the hydraulic fluid under pressure entering the cage pressure port to flow out of the sequential stepped directional control valve through the cage first stage port, the spool allows hydraulic fluid to flow through the cage second stage port into the sequential stepped directional control valve and the spool directs hydraulic fluid entering the second stage port into the sequential stepped directional control valve to flow out of the sequential stepped directional control valve through the tank port, and the spool blocks hydraulic fluid from the cage first stage port from flowing out of the sequential stepped directional control valve through the tank port; and (3) when the spool is in the second stage operating position, the spool allows hydraulic fluid under pressure to flow through the cage pressure port into the sequential stepped directional control valve and the spool directs the hydraulic fluid under pressure entering the cage pressure port to flow out of the sequential stepped directional control valve through the cage first stage port and through the cage second stage port, and the spool blocks hydraulic fluid from the cage first stage port and from the cage second stage port from flowing out of the sequential stepped directional control valve through the tank port. 2. The sequential stepped directional control valve of claim 1 wherein the spool moves from the first stage operating position to the second stage operating position without ever being in the neutral position. 3. The sequential stepped directional control valve of claim 1 wherein the spool moves from the first stage operating position to the second stage operating position without interrupting the flow of hydraulic fluid under pressure from flowing through the cage pressure port into the sequential stepped directional control valve and without interrupting the direction by the spool of the hydraulic fluid under pressure entering the cage pressure port to flow out of the sequential stepped directional control valve through the cage first stage port. 4. The sequential stepped directional control valve of claim 2 wherein the cage is pierced by a cage pressure port in substantially the radial direction, the cage is pierced by a cage first stage port in substantially the radial direction, the cage is pierced by a cage second stage port in substantially the radial direction, and the cage is pierced by a cage pump port in substantially the axial direction. 5. The sequential stepped directional control valve of claim 3 wherein the cage is pierced by a cage pressure port in substantially the radial direction, the cage is pierced by a cage first stage port in substantially the radial direction, the cage is pierced by a cage second stage port in substantially the radial direction, and the cage is pierced by a cage pump port in substantially the axial direction. 6. The sequential stepped directional control valve of claim 4 wherein the pole piece is a pull pole piece, and the magnetic force produced in response to electrical current being applied to the solenoid coil acts to pull the plunger and the spool attached to the plunger toward the pull pole piece. 7. The sequential stepped directional control valve of claim 5 wherein the pole piece is a pull pole piece, and the magnetic force produced in response to electrical current being applied to the solenoid coil acts to pull the plunger and the spool attached to the plunger toward the pull pole piece. 8. The sequential stepped directional control valve of claim 6 wherein (A) the second predetermined electrical current is greater than the first predetermined electrical current; (B) the plunger is closer to the pull pole piece when the spool attached to the plunger is in the second operating position than when the spool attached to the plunger is in the first operating position; and (C) the plunger is closer to the pull pole piece when the spool attached to the plunger is in the first operating position than when the spool attached to the plunger is in the neutral position. 9. The sequential stepped directional control valve of claim 7 wherein (A) the second predetermined electrical current is greater than the first predetermined electrical current; (B) the plunger is closer to the pull pole piece when the spool attached to the plunger is in the second operating position than when the spool attached to the plunger is in the first operating position; and (C) the plunger is closer to the pull pole piece when the spool attached to the plunger is in the first operating position than when the spool attached to the plunger is in the neutral position. 10. A sequential stepped directional control valve having at least three operating positions, in which one of the operating positions is a neutral position, comprising: (A) a hollow cage having an axial direction and a radial direction substantially transverse to the axial direction of the cage, the cage having an outer cage wall, the cage having in inner cage wall defining a hollow cage central passage, the cage being pierced by a cage pressure port connecting the outer cage wall and the cage central passage, by a cage first stage port connecting the outer cage wall and the cage central passage, by a cage second stage port connecting the outer cage wall and the cage central passage, and by a cage pump port connecting the outer cage wall and the cage central passage;(B) a spool adapted to fit snugly within the cage in which location the spool is moveable relative to the cage in a direction substantially parallel to the axial direction of the cage, the spool having an axial direction substantially parallel to the axial direction of the cage and a radial direction substantially parallel to the radial direction of the cage, the spool having a outer spool wall, the spool further having a hollow central spool passage extending in a direction substantially parallel with the axial direction of the cage, the spool being pierced by a spool first stage port connecting the outer spool wall and the central spool passage, the spool being pierced by a spool second stage port connecting the outer spool wall and the central spool passage, and the spool being pierced by a spool tank port connecting the outer spool wall and the central spool passage;(C) the spool having (1) a first spool cavity comprising a first radially inward indentation of the outer spool wall wherein, when the spool is within the cage, the first radially inward indentation of the outer spool wall interacting with the inner cage wall to define a cavity between the spool outer wall and the cage inner wall, and (2) a second spool cavity comprising a second radially inward indentation of the outer spool wall wherein, when the spool is within the cage, the second radially inward indentation of the outer spool wall interacting with the inner cage wall to define a cavity between the spool outer wall and the cage inner wall;(D) a solenoid coil substantially annularly surrounding a pole piece adapted to produce a magnetic force in response to an electrical current applied to the solenoid coil;(E) a magnetically responsive plunger attached to the spool, the plunger being magnetically responsive to the magnetic force produced by the pole piece;(F) one or more springs within the sequential stepped directional control valve directly or indirectly biasing the spool in the axial direction of the spool;(G) wherein (1) when no electrical current is applied to the solenoid coil, the springs within the sequential stepped directional control valve directly or indirectly bias the spool such that the spool is located in the neutral position; (2) when a first predetermined electrical current is applied to the solenoid coil, the magnetic force produced in the pole piece acts upon the plunger to counteract the biasing caused by the springs directly or indirectly upon the spool so as to cause the plunger to move to a position within the sequential stepped directional control valve such that the spool attached to the plunger is located in a first stage operating position different from the neutral position; and (3) when a second predetermined electrical current is applied to the solenoid coil, the magnetic force produced in the pole piece acts upon the plunger to counteract the biasing caused by the springs directly or indirectly upon the spool so as to cause the plunger to move to a position within the sequential stepped directional control valve such that the spool attached to the plunger is located in a second stage operating position different from the neutral position and different from the first stage operating position; and(H) wherein (1) when the spool is in the neutral position (a) the spool blocks hydraulic fluid under pressure from entering the cage central passage of the sequential stepped directional control valve through the cage pressure port, (b) the spool first stage port is aligned with the cage first stage port and the spool tank port is aligned the with cage tank port, so that hydraulic fluid may flow through the cage first stage port and through the aligned spool first stage port into the central spool passage and from the central spool passage through the spool tank port and out of the sequential stepped directional control valve through the cage tank port aligned with the spool tank port, (c) the spool second stage port is aligned with the cage second stage port, so that hydraulic fluid may flow through the cage second stage port and through the aligned spool second stage port into the central spool passage and from the central spool passage through the spool tank port and out of the sequential stepped directional control valve through the cage tank port aligned with the spool tank port; (2) when the spool is in the first stage operating position (a) the first spool cavity is simultaneously aligned with both the cage pressure port and the cage first stage port, resulting in hydraulic fluid under pressure flowing into the sequential stepped directional control valve through the cage pressure port into the first spool cavity, and hydraulic fluid under pressure in the first spool cavity flowing out of the sequential stepped directional control valve through the cage first stage port with which the first spool cavity is aligned, (b) the spool first stage port is blocked by the cage inner wall, (c) the spool second stage port is aligned with the cage second stage port and the spool tank port is aligned the with cage tank port, so that hydraulic fluid may flow through the cage second stage port and through the aligned spool second stage port into the central spool passage and from the central spool passage through the spool tank port and out of the sequential stepped directional control valve through the cage tank port aligned with the spool tank port; and (3) when the spool is in the second stage operating position (a) the first spool cavity is simultaneously aligned with both the cage pressure port and the cage first stage port, resulting in hydraulic fluid under pressure flowing into the sequential stepped directional control valve through the cage pressure port into the first spool cavity, and hydraulic fluid under pressure in the first spool cavity flowing out of the sequential stepped directional control valve through the cage first stage port with which the first spool cavity is aligned, (b) the second spool cavity is simultaneously aligned with both the cage first stage port and the cage second stage port, resulting in hydraulic fluid under pressure in the cage first stage port flowing into the second spool cavity, and hydraulic fluid under pressure in the second spool cavity flowing out of the sequential stepped directional control valve through the cage second stage port with which the second spool cavity is aligned, and (c) the spool first stage port and the spool second stage port are blocked by the cage inner wall. 11. The sequential stepped directional control valve of claim 10 wherein the spool moves from the first stage operating position to the second stage operating position without ever being in the neutral position. 12. The sequential stepped directional control valve of claim 10 wherein the spool moves from the first stage operating position to the second stage operating position without interrupting the flow of hydraulic fluid under pressure from flowing through the cage pressure port into the sequential stepped directional control valve and without interrupting the flow of hydraulic fluid under pressure out of the sequential stepped directional control valve through the cage first stage port. 13. The sequential stepped directional control valve of claim 11 wherein the cage is pierced by a cage pressure port in substantially the radial direction, the cage is pierced by a cage first stage port in substantially the radial direction, the cage is pierced by a cage second stage port in substantially the radial direction, and the cage is pierced by a cage pump port in substantially the axial direction. 14. The sequential stepped directional control valve of claim 12 wherein the cage is pierced by a cage pressure port in substantially the radial direction, the cage is pierced by a cage first stage port in substantially the radial direction, the cage is pierced by a cage second stage port in substantially the radial direction, and the cage is pierced by a cage pump port in substantially the axial direction. 15. The sequential stepped directional control valve of claim 13 wherein (A) the pole piece is a pull pole piece, and the magnetic force produced in response to electrical current being applied to the solenoid coil acts to pull the plunger and the spool attached to the plunger toward the pull pole piece; and (B) the springs within the sequential stepped directional control valve directly or indirectly bias the spool in the axial direction of the spool in a direction away from the pull pole piece. 16. The sequential stepped directional control valve of claim 14 wherein (A) the pole piece is a pull pole piece, and the magnetic force produced in response to electrical current being applied to the solenoid coil acts to pull the plunger and the spool attached to the plunger toward the pull pole piece; and (B) the springs within the sequential stepped directional control valve directly or indirectly bias the spool in the axial direction of the spool in a direction away from the pull pole piece. 17. The sequential stepped directional control valve of claim 15 wherein (A) the second predetermined electrical current is greater than the first predetermined electrical current; (B) the plunger is pulled closer to the pull pole piece when the second predetermined current is applied to the solenoid coil resulting in the spool attached to the plunger being in the second operating position than when the first predetermined is applied to the solenoid coil resulting in the spool attached to the plunger being in the first operating position; and (C) the plunger is pulled closer to the pull pole piece when the first predetermined is applied to the solenoid coil resulting in the spool attached to the plunger being in the first operating position than when the spool attached to the plunger is in the neutral position. 18. The sequential stepped directional control valve of claim 16 wherein (A) the second predetermined electrical current is greater than the first predetermined electrical current; (B) the plunger is pulled closer to the pull pole piece when the second predetermined current is applied to the solenoid coil resulting in the spool attached to the plunger being in the second operating position than when the first predetermined is applied to the solenoid coil resulting in the spool attached to the plunger being in the first operating position; and (C) the plunger is pulled closer to the pull pole piece when the first predetermined is applied to the solenoid coil resulting in the spool attached to the plunger being in the first operating position than when the spool attached to the plunger is in the neutral position. 19. The sequential stepped directional control valve of claim 1 wherein intermediate proportional position control occurs within a first stage operating position or within a second stage operating position by applying pulse width modulated current to the solenoid coil. 20. The sequential stepped directional control valve of claim 10 wherein intermediate proportional position control occurs within a first stage operating position or within a second stage operating position by applying pulse width modulated current to the solenoid coil.