Proportional pilot operated directional valve

A valve comprising:

• a sleeve comprising a wall with an inner surface, a first end and a second end, the inner surface defining an axial bore, at least first, second, third and fourth sets of radial holes being defined in the wall of the sleeve;
• a spool disposed within the axial bore of the sleeve, the spool comprising:
• a wall with an inner surface and an exterior surface, the inner surface defining an axial bore, at least two sets of radial holes being defined in the wall of the spool, the two sets of radial holes at least partially communicating with the axial bore of the spool, the exterior surface of the spool comprising:
• a generally cylindrical portion between the two sets of radial holes of the spool,
• a plurality of annular protrusions, each being in at least partial contact with the inner surface of the wall of the sleeve, at least one of the plurality of annular protrusions being disposed between one of the two sets of radial holes and the generally cylindrical portion, at least another of the plurality of annular protrusions being disposed between the other of the two sets of radial holes and the generally cylindrical portion, the generally cylindrical portion extending from about one of the plurality of annular protrusions to about another of the plurality of annular protrusions,
• wherein the generally cylindrical portion, the annular protrusions between which the cylindrical portion extends, and the inner surface of the sleeve define a channel,
• wherein, when the spool is in a neutral position, the first set of radial holes of the sleeve is blocked by an annular protrusion of the plurality of the annual protrusions of the spool, the second set of radial holes of the sleeve is at least in partial communication with the channel, the third set of radial holes of the sleeve is blocked by an annular protrusion of the plurality of the annual protrusions of the spool, and the fourth set of radial holes of the sleeve is at least in partial communication with at least one of the two sets of radial holes of the spool;
• a cap having an axial bore, wherein the first end of the sleeve is disposed inside the axial bore of the cap and is connected to the cap,
• a generally tubular first guide member disposed within the axial bore of the cap and movable within the axial bore of the cap, the first guide member having an axial through-bore;
• a generally tubular second guide member disposed within the axial bore of the cap between the first guide member and the spool, the second guide member having an axial through-bore that is approximately aligned with the axial through-bore of the first guide member;
• a generally cylindrical connecting member disposed within the axial bore of the cap and extending through the axial bores of both the first and second guide members, the generally cylindrical guide member, the connecting member having
• a first end disposed in the axial through-bore of the first guide member, the first end having an annular lip whose diameter is greater than that of a portion of the axial through-bore of the first guide member, and
• a second end that disposed in the axial through-bore of the second guide member and is connected to the spool;
• and
• a means for urging the first and second guide members apart.

A valve comprising:

• a sleeve having a wall with an inner surface, the inner surface defining an axial bore, the sleeve wall having at least a first, a second, a third and a fourth set of radial holes;
• a spool disposed within the axial bore of the sleeve, the spool having a wall with an inner surface defining an axial bore, a first end, and a second end, the spool having an exterior surface, at least two sets of radial holes being defined in the wall of the spool, the two sets of radial holes at least partially communicating with the axial bore of the spool,
• wherein the exterior surface of the spool comprises at least three annular protrusions spaced apart from one another, wherein one of the three annular protrusions is located at an intermediate position between the other two annular protrusions, another of the three annular protrusions is located closer to the second end of the spool than the other two annular protrusions, and the remaining one of the three annular protrusions is located closer to the first end of the spool than the other two annular protrusions,
• wherein one of the two sets of radial holes of the spool is located between the annular protrusion at the intermediate position and the annular protrusion that is closer to the first end of the spool,
• wherein the other of the two sets of radial holes is located between the annular protrusion that is located closer to the first end of the spool and the first end of the spool,
• wherein the generally cylindrical portion extends from about the annular protrusion that is closer to the second end of the spool to about the annular protrusion located at the intermediate position, and wherein the generally cylindrical portion, the two annular protrusions between which the cylindrical portion extends, and the inner surface the sleeve define a channel,
• wherein the first and second sets of radial holes of the sleeve are at least in partial communication with the channel, the third set of radial holes of the sleeve is at least in partial communication with one of the two sets of radial holes of the spool, and the fourth set of radial holes of the sleeve is at least in partial communication with the other of the two sets of radial holes of the spool;
• a cap having an axial bore, wherein the first end of the sleeve is disposed inside the axial bore of the cap and is connected to the cap;
• a generally tubular first guide member disposed within the axial bore of the cap and movable within the axial bore of the cap, the first guide member having an axial through-bore;
• a generally tubular second guide member disposed within the axial bore of the cap between the first guide member and the spool, the second guide member having an axial through-bore that is approximately aligned with the axial through-bore of the first guide member;
• a generally cylindrical connecting member disposed within the axial bore of the cap and extending through the axial-through bores of both the first and second guide members, the connecting member comprising a first end and a second end, the first end extending out from the axial through-bore of the first guide member, the first end having an annular lip whose diameter is greater than that of a portion of the axial through-bore of the first guide member, the second end extending out from the axial through-bore of the second guide member, the second end being connected to the spool;
• and
• a means for urging the first and second guide members apart.

A valve comprising:

• a sleeve having a first and a second end, an opening at the second end, at least a first, a second, a third and a fourth set of radial holes, a wall with an inner surface defining an axial bore;
• a spool disposed within the axial bore, the spool having a wall with an interior surface defining an axial bore and an exterior surface, the spool wall having at least a first set, a second set, and a third set of radial holes at least partially communicating with the axial bore of the spool the exterior surface of the spool wall comprising:
• at least a first, a second, a third, a fourth and a fifth annular protrusion, the first set of radial holes of the spool wall being located between the first and second annular protrusions, the second set of radial holes of the spool wall being located between the second and third annular protrusions, and the third set of radial holes of the spool wall being located between the fourth and fifth annular protrusions,
• a generally cylindrical portion extending from about the second annular protrusion to about the third annular protrusion, and wherein the generally cylindrical portion, the second annular protrusion, the third annular protrusion, and the inner surface of the sleeve define a channel;
• and
• a cap having an axial bore and a radial hole, wherein the first end of the sleeve is disposed inside the axial bore of the cap, and is connected to the cap, wherein the radial hole of the cap at least partially communicates with the axial bore of the cap, and wherein a fluid path is defined from the radial hole of the cap, through the axial bore of the cap, and to the spool;
• wherein the spool is movable within the axial bore, the spool having at least:
• a neutral position, in which the third annular protrusion blocks the third set of radial holes of the sleeve and the fourth annular protrusion blocks the first set of radial holes of the sleeve,
• a first open position in which the first set of radial holes of the sleeve is at least in partial communication with one of the three sets of radial holes of the spool, the second and third sets of radial holes of the sleeve are each at least in partial communication with the channel, and the fourth set of radial holes of the sleeve is at least in partial communication with another of the three sets of radial holes of the spool, and
• a second open position, in which the first and second sets of radial holes of the sleeve are at least in partial communication with the channel, the third set of radial holes of the sleeve is at least in partial communication with one of the three sets of radial holes of the spool, and the fourth set of radial holes of the sleeve is at least in partial communication with another of the three sets of radial holes of the spool.

A method for regulating the flow of fluid through a valve comprising a generally tubular sleeve having at least a first, a second, a third and a fourth set of radial holes;

• and a spool having axial bore and being disposed within the sleeve, a channel being defined between the spool and the sleeve, a first guide member moveable within the valve along an axis of the valve, the first guide member having an axial through-bore;
• a second guide member moveable within the valve along an axis of the valve, the second guide member having an axial through-bore;
• a connecting member extending through the axial through-bores of the first and second guide members, the connecting member comprising a first end that is disposed in the axial through-bore of the first guide member, the first end including a means for engaging the first guide member, and a second end that is disposed in the axial through-bore of the second guide member and that engages the spool;
• and a means for urging the first and second guide members apart, the method comprising:
• accepting a pilot flow into the valve;
• passing the pilot flow to a point near the spool, thereby causing the spool to move along the axis of the sleeve so as to unblock at least one of the sets of the radial holes of the sleeve;
• the connecting member moving in response to the movement of the spool and disengaging the first guide member;
• the second guide member moving in response to the spool and exerting a force on the urging means;
• the urging means counterbalancing the force;
• admitting a fluid through the second set of radial holes and into the channel;
• passing the fluid through the channel and to the third set of radial holes;
• allowing the fluid to exit the valve at the third set of radial holes and pass to a hydraulic device;
• admitting the fluid from an outlet of the hydraulic device, through the fourth set of radial holes, and to the axial bore of the spool;
• passing the fluid through the axial bore of the spool and to the fourth set of radial holes;
• and
• allowing the fluid to exit the valve at the fourth set of radial holes.