Proportional solenoid-controlled fluid valve having compact pressure-balancing armature-poppet assembly

Abstract

A proportional solenoid-driven valve control assembly contains a moveable, magnetic armature adjacent to a fixed pole piece, providing fluid leakage containment, and having no non-magnetic element for alignment, support or magnetic flux path control. A valve unit coupled with the armature contains a fluid cavity in fluid communication with a fluid inlet port and a fluid exit port. The valve is closed by a poppet coupled with the armature. To compensate for fluid pressures exerted against the poppet, a flow restriction is provided between an armature cavity and the fluid cavity. Also, a bore is formed through the armature to provide fluid communication between the fluid exit port and the armature cavity. This serves to balance fluid pressures at the fluid inlet and exit ports applied to the opposite sides of the fluid flow restriction.

Description

FIELD OF THE INVENTION

[0002] The present invention relates in general to solenoid-actuated fluid control valves of the type disclosed in the above-referenced applications and Patents, for use in precision fluid flow regulation systems, such as those that require precise control of the rate of fluid flow, including but not limited to pneumatic and hydraulic regulation. The present invention is particularly directed to a reduced hardware complexity configuration for effectively balancing inlet and outlet pressures of the fluid ports of the valve, so that valve poppet position will be defined exclusively by the solenoid, thereby ensuring precision control of fluid flow through the valve.

BACKGROUND OF THE INVENTION

[0003] A number of precision fluid metering applications, such as micro-pneumatic and fuel injection systems, as non-limiting examples, employ solenoid-driven actuators to control fluid flow through a fluid supply valve. Optimally, fluid flow through the valve is to be maintained very closely proportional to the current applied to the solenoid. However, varying fluid pressure conditions at the valve's inlet and/or outlet ports can significantly impact the ability of the solenoid to provide the precise metering control desired.

[0004] In order to deal with this problem, it is common practice to incorporate into the valve a pressure balancing sub-assembly, such as a dual diaphragm-based pressure-balancing mechanism of the type diagrammatically shown in cross-section in FIG. 1. This dual diaphragm mechanism serves to compensate or effectively ‘balance’ out the fluid pressures at each of its inlet and outlet ports, in order that the only translation forces acting on the valve orifice-closing poppet will be those imparted by the solenoid-driven armature.

[0005] More particularly, in the valve architecture of FIG. 1, compensation for the pressure P1 of a fluid applied to a valve inlet port 11 of a solenoid-operated fluid valve 10 is provided by an ‘upper’ diaphragm 21, installed between an armature-poppet connecting rod 23 and a solenoid actuator assembly 25. The upper end of the connecting rod 23 engages the moveable armature 24 of the solenoid actuator, while the lower of the connecting rod 23 engages a poppet 27, that is sized to be closed against a valve seat 31 surrounding a valve orifice 33. The valve orifice 33 provides fluid communication between a fluid cavity 35, to which fluid inlet pressure P1 at the valve inlet port 11 is applied, and a fluid exit port 37 from which fluid at a valve outlet pressure P2 is derived.

[0006] By making the annular area AD1 of the ‘upper’ diaphragm 21 substantially the same as or very close to that of the area AO of the orifice 33, the downward force (as viewed in FIG. 1) imparted by the inlet fluid pressure P1 against the poppet 27 will be substantially the same as or performance-wise sufficiently close to the ‘upward’ force imparted by the pressure P1 against the upper diaphragm 21, thereby effectively neutralizing the contribution of the pressure P1 to the position of the valve poppet 27 relative to the valve seat 31.

[0007] In a complementary manner, compensation for the fluid pressure P2 at the exit port 37 is provided by a ‘lower’ diaphragm 41, installed between the lower end 43 of a poppet-connecting rod 45 and the valve body 47. The upper end 51 of the connecting rod 45 engages the poppet 27. Similar to the compensation mechanism for the pressure P1, the annular area AD2 of the ‘lower’ diaphragm 41 is made substantially the same as or very close to that of the area AO of the orifice 33.

[0008] As a consequence, any upward force imparted by the pressure P2 against the poppet 27, that might otherwise tend to lift the poppet off the valve seat 31 (and thereby undesirably render solenoid control ineffective), will be countered by ‘downward’ force imparted by the pressure P2 against the lower diaphragm 41, so as to effectively neutralize the contribution of the pressure P2 to the position of the valve poppet 27 relative to valve seat 31.

[0009] Now, although a dual diaphragm-based pressure compensation structure of the type shown in FIG. 1 is effective for its intended purpose, it is hardware intensive in terms of the added diaphragm, connecting rods and increased sized and additional boring of the valve body proper. This added hardware complexity not only increases the size of the assembly, but the cost and complexity of its manufacture, as well.

SUMMARY OF THE INVENTION

[0010] In accordance with the present invention, advantage is taken of the magnetic field coupling and fluid containment structure of the integrated ferromagnetic pole piece employed in the solenoid-operated valve described in the above-referenced '______ application, to incorporate a poppet/armature bore-based, pressure-balancing scheme, that not only ensures that valve poppet position will be defined exclusively by the solenoid, but does so in a manner that allows the hardware complexity, size and cost of assembly to be significantly reduced relative to the prior art, such as the dual diaphragm structure, described above.

[0011] As will be described, the pressure balanced, solenoid-controlled fluid valve assembly of the invention includes a valve unit and a solenoid-driven, valve actuator. The solenoid-driven, valve actuator unit is preferably of the type described in my above-referenced '______ application, having an integrated magnetic pole piece that provides fluid leakage containment. It also couples axial, radial and magnetic shunt flux paths with a moveable armature without the need for non-magnetic material for alignment, support or magnetic flux flow path control. The valve unit is similar to the those of the above-referenced '425 application, and the '947 and '033 Patents, positioning a valve poppet relative to a fluid flow orifice through the valve proper.

[0012] To balance out inlet and exit port fluid pressures, the valve unit incorporates a fluid flow restriction with the armature/poppet-positioning mechanism between the armature cavity and the fluid inlet cavity. In addition, the poppet and its poppet-positioning armature have an interior bore that serves as an auxiliary fluid path between the fluid exit port and the armature cavity. This combination is effective to balance fluid pressures at the fluid inlet and exit ports applied to the opposite sides of the restriction, in a manner that is complementary to the fluid pressures applied to opposite sides of the poppet, thereby effectively neutralizing the effects of fluid pressure on poppet position.

[0013] In a first embodiment, a poppet/armature assembly is coupled with a pressure-balancing diaphragm, that has an annular area substantially the same as or very close to the area of the valve bore orifice. The diaphragm is retained by an armature support member, so as to provide a fluid seal between an upper armature cavity containing the armature, and a cavity containing the valve seat, and ported to the fluid inlet port.

[0014] The valve actuator unit includes a unitary pole piece having a generally axial pole piece portion, that extends into an upper solenoid/pole piece cavity coupled in fluid communication with the upper armature cavity by way of an annular fluid gap. Fluid leakage containment for this upper cavity structure is provided by the fluid-sealing structure of the pole piece and the diaphragm. The integral pole piece and support architecture do not require a non-magnetic material in the magnetic flux flow path. An axial bore in the lower end of the axial portion of the pole piece accommodates a compression spring urged against the armature and axially biases the armature, and thereby the poppet against the valve seat.

[0015] An auxiliary axial bore through the armature provides fluid communication between the valve bore, (which is in fluid communication with the fluid exit port, and the axial gap between the lower distal end of the axial portion of the magnetic pole piece. Since the axial gap is in fluid communication with the upper (fluid leakage-contained) cavity structure that includes the upper solenoid/pole piece cavity and the armature cavity, it couples the exit port pressure to the top side of the fluid restriction diaphragm.

[0016] Since, the area of the fluid restriction diaphragm is substantially the same as the valve bore orifice upward force imparted against the poppet by the fluid exit port pressure is countered by a downward force at that same pressure, that has coupled through the auxiliary bore to the top of the diaphragm. In a complementary manner, the pressure at the fluid inlet port is balanced as a result of a downward force imparted by the inlet fluid pressure against the poppet being substantially the same as the upward force imparted by the pressure against the bottom of the fluid restriction diaphragm.

[0017] In a second embodiment, the fluid restriction comprises an O-ring inserted into an annular groove of an armature support member. Similar to the diaphragm of the first embodiment, this O-ring has an annular area substantially the same as or very close to that of the area of the valve bore orifice. A single spiral-configured suspension spring supports the armature-poppet. The pressure-balancing function provided by the O-ring is similar to that of the diaphragm in the first embodiment.

[0018] Pursuant to a third embodiment, the fluid restriction mechanism is implemented without a captured element; instead, the restriction is defined by the geometry of a very narrow annular aperture between the outer surface of the armature-poppet and the inner surface of an armature insertion bore through the surrounding support member. The geometric parameters of the armature-poppet, including its outer diameter and auxiliary internal bore size, and those of the armature insertion bore through the support member, are such as to limit or restrict ‘upward’ fluid flow of the inlet pressure and ‘downward’ fluid flow of the outlet pressure, in a manner that is proximate the force imparted by these pressures on opposite sides of the armature-poppet relative to the valve orifice. This neutralizes the contribution of the fluid inlet and outlet pressures on the position of the armature-poppet relative to the valve seat.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a longitudinal, cross-sectional diagrammatic illustration of a proportional solenoid-controlled fluid valve assembly containing a conventional dual diaphragm-based fluid pressure compensation mechanism;

[0020] FIG. 2 is a longitudinal, cross-sectional diagrammatic illustration of a first embodiment of the improved proportional solenoid-controlled fluid valve assembly embodying the fluid pressure compensation scheme of the invention;

[0021] FIG. 3 diagrammatically illustrates a second embodiment of the invention, in which the fluid restriction mechanism is implemented by means of an O-ring inserted into an annular groove of an armature support member; and

[0022] FIG. 4 diagrammatically shows a third embodiment of the invention, in which the fluid restriction mechanism is implemented by a narrow annular aperture between the outer surface of the armature-poppet and the inner surface of an armature insertion bore in the armature support member.

DETAILED DESCRIPTION

[0023] Attention is now directed to FIG. 2, which is a longitudinal, cross-sectional diagrammatic illustration of a proportional solenoid-controlled fluid valve, having a fluid pressure balancing arrangement in accordance with a first embodiment of the invention. Unless otherwise indicated or inherently apparent, the architecture of FIG. 2 (as well as those of FIGS. 3 and 4) is cylindrically symmetrical about a longitudinal axis A.

[0024] As pointed out briefly above, and as will be detailed below, this arrangement employs a fluid flow restriction between the armature cavity and the fluid inlet cavity, plus a fluid communication path through the valve closing assembly between the fluid exit port and the armature cavity. The combination of these two mechanisms effectively balances both the inlet and outlet forces acting upon the valve poppet, so that valve poppet position is controlled exclusively by the solenoid.

[0025] The solenoid-controlled fluid valve assembly includes a valve unit 200 the fluid flow path through which is controlled by a solenoid-driven, valve actuator unit 300. The solenoid-driven, valve actuator unit 300 is preferably of the type described in my above-referenced '______ application, and employs an integrated magnetic pole piece that is configured to provide fluid leakage containment, as well as axial, radial and magnetic shunt flux paths with a moveable armature that drives the valve poppet, but without the conventional need for non-magnetic material for alignment, support or magnetic flux flow path control.

[0026] The valve unit 200 is similar to the valve units of the solenoid-controlled valve assemblies of the above-referenced '425 application, and the '947 and '033 Patents, and is operative, under solenoid-driven actuator control, to position a valve poppet relative to a fluid flow orifice through the valve proper. To balance out inlet and exit port fluid pressures, valve unit 200 incorporates a fluid flow restriction coupled to the armature/poppet-positioning mechanism between the armature cavity and the fluid inlet cavity. In addition, the poppet and its associated poppet-positioning armature are provided within an interior bore that provides a fluid communication path between the fluid exit port and the armature cavity.

[0027] As pointed out above, and as will be detailed below, this combination of the fluid flow restriction and the fluid communication path causes fluid pressures at the fluid inlet and exit ports to be applied to the opposite sides of the restriction, in a manner that is complementary to the fluid pressures applied to opposite sides of the poppet, thereby effectively neutralizing the effects of fluid pressure on poppet position.

[0028] More particularly, the valve unit 200 is shown as comprising a generally cylindrical base member 202 having a fluid input port 204 and a fluid exit port 206. Each of the fluid input and exit ports, which may be respectively interiorly threaded, as shown at 208 and 210, respectively, so as to facilitate their being coupled to respective sections of fluid transporting conduit (not shown). Within the generally cylindrical valve base member 202, the fluid exit port 206 is coupled to a first generally cylindrical interior valve bore 212 that extends to a valve orifice 214, that terminates at and is surrounded by a (generally circular) valve seat 216.

[0029] Although the valve seat 216 is shown as being fixed within the body 202 of valve unit 200, it may alternatively be configured as an adjustable valve seat, such as one installed in a threaded portion of the valve bore (as shown diagrammatically in the embodiments of FIGS. 3 and 4, to be described). In this alternative configuration, the valve seat may be maintained in a fluid sealed condition within the valve bore 212 by means of one or more (e.g., a pair of) O-rings. The orifice 214 of the valve bore 212 opens into an interior valve poppet cavity 218 in which a valve poppet 220 is retained by an translatable, axially bored armature 222 for solenoid-controlled closure against and opening away from the valve seat 216. The valve poppet cavity 222 is coupled to the fluid inlet port 204 by way of a bore 224 therebetween.

[0030] As further shown in FIG. 2, valve poppet 220 may have a generally stepped cylindrical body 226, which terminates at a lower generally circular face 228. The poppet face 228 has a depression 230, into which a fluid tight sealing ring 232, such as an annular shaped neoprene ring, may be press fit. This annular sealing ring 232 is sized to cover and thereby seal the poppet 220 against the circular valve seat 216, when brought into closing contact thereagainst by the solenoid-driven armature 222.

[0031] The valve poppet 220 also includes an interior axial bore 234, which is sized to snugly engage and fit upon the outer cylindrical surface 236 of a lower narrow cylindrical end 238 of the axially bored armature 222. When the valve poppet 220 is affixed upon the lower cylindrical end 238 of the armature 222, it retains an interior ring portion 240 of a diaphragm 242 against the lower surface 244 of the armature 222. Like the upper diaphragm 21 in the dual diaphragm structure of FIG. 1, the diaphragm 242 has an annular area A242 that is substantially the same as or very close to that of the area A214 of the bore orifice 214.

[0032] A relatively increased thickness, generally circular circumferential portion 246 of the diaphragm 242 is captured and sealed between an interiorly projecting radial portion 248 of an inverted, generally cup-shaped armature support member 250, and a retaining ring 252 that is fit (e.g., threaded) into a generally circular depression 254 of the support member 250. When so captured, the diaphragm 242 provides a fluid seal between an upper armature cavity 256 containing the armature 222 and the valve poppet cavity 218 containing the poppet 220 and the valve seat 216.

[0033] The axially translatable armature 222 has a generally annular shoulder 260 that is adapted to cooperate with an associated surface 262 of the support member 250, so as to support a first spiral-configured suspension spring 264 on a first side of an inner spring-retaining, ferrule-shaped spacer 266, that is sized to fit around the outer cylindrical surface 268 of the armature 222.

[0034] A second spiral-configured suspension spring 270 is captured between a second side of the inner ferrule-shaped spacer 266 and a generally cylindrically shaped armature sleeve 272, that is retained upon an upper portion 274 of the armature 222. A generally outer circumferential region 276 of the second spiral suspension spring 270 is captured between a generally disc-shaped support member 278 atop the support member 250 and an interior surface portion 302 of a lower, cup-shaped portion 304 of a ferromagnetic pole piece 306 of solenoid-driven, valve actuator unit 300.

[0035] As pointed out briefly above, and as will be described, the solenoid-driven, the valve actuator unit 300 is preferably configured essentially as shown and detailed in the above-referenced '______ application. The cup-shaped portion 304 of the pole piece 306 may threadingly engage the outer cylindrical surface 280 of support member 250, with an O-ring 282 providing a fluid seal therebetween. The valve body 202 is sized to receive and engage a lower interior cylindrical portion 308 of the cup-shaped portion 304 of the pole piece 306.

[0036] The solenoid-driven, valve actuator unit 300 may be securely attached to the valve unit 200 by way of set-screws (not shown) inserted through bores (two of which are shown at 310 and 312) in the pole piece 306, and screwed into tapped bores (not shown) in the upper surface 203 of the valve body 202. An O-ring 284 is captured between a generally circular slot 286 of the lower surface 288 of the support member 250 and the valve body 202, so as to seal the support member 250 against valve body 202, and thereby provide a sealed or contained fluid flow path between the fluid inlet and exit ports and the poppet cavity 218.

[0037] The axially translatable armature 222 and associated armature sleeve 274 extend through a generally cylindrical annular bore 314 formed by a radially inward projecting portion 316 of magnetic pole piece 306 (that is solid with the cup-shaped portion 304 thereof). As a result, an outer cylindrical surface 290 of armature sleeve 274 is slightly radially spaced apart from the interior cylindrical surface 318 of radially inward projection 316 of the pole piece and forms a narrow annular fluid (air) gap 320 therebetween.

[0038] The generally cylindrical annular bore 314 opens into a upper solenoid/pole piece cavity 341, that is bounded by a relatively thin portion 342 of a generally annular sleeve pole piece portion 340 of the magnetic pole piece 306. This upper cavity 341 is coupled in fluid communication with the upper armature cavity 256 by way of the annular air gap 320. As will be described, fluid leakage containment for this upper cavity structure is provided by the fluid-sealing integrated structure of the pole piece 306, on the one hand, and the diaphragm 242, on the other hand. (As noted earlier, the diaphragm 242 provides a fluid seal between an upper armature cavity 256 containing armature 222 and the valve poppet cavity 218, in which the poppet 220 and the valve seat 216 are disposed.)

[0039] Because the annular air gap 320 is very narrow and of a fixed radial distance, the magnetic flux path between the armature 222 and the radially inward projecting portion 316 of the magnetic pole piece 306 is a low magnetic reluctance radial path. Thus, as in the patented architectures, referenced above, the substantial reluctance of the axial air gap 336 between the moveable armature 222 and the distal end of the generally axial portion 322 of the magnetic pole piece, in combination with the relatively low magnetic reluctance in the radial direction across the radial air gaps, effectively by-passes the axial air gap and confines the magnetic flux in radial air gap regions.

[0040] The armature 222 terminates at a generally planar, circular top surface 294 adjacent to a generally axial or longitudinal portion 322 of the magnetic pole piece 306. The generally axial portion 322 of the magnetic pole piece 306 is configured of a generally cylindrical solid ferromagnetic element, that is generally coaxial with the axis A and is sized to fit within the generally cylindrical bore 324 of a solenoid coil 326. As shown, the solenoid coil may be installed within a housing 328 of ferromagnetic material. The housing 328 may be provided with a sidewall aperture or bore 329 for electrical leads 332 that supply electrical connection between the solenoid coil and a current control source (not shown).

[0041] The generally axial portion 322 of the magnetic pole piece 306 has a lower distal end 334 that is axially spaced apart from and magnetically coupled with the top generally circular surface 294 of axially translatable armature 222, so as to form an axial air gap 335 therebetween. An axial bore 323 formed in the lower end of the axial portion 322 of the pole piece 306 receives a compression spring 325 that is urged against the top surface 294 of the axially translatable armature 222, and serves to axially bias the armature 222 and its associated poppet 220 downwardly so that the poppet is urged against the valve seat 216.

[0042] Extending axially outwardly from the distal end 334 of the generally axial portion 322 of the magnetic pole piece 306 is a generally tubular or ferrule-shaped projection 336, having a tapered or varying thickness in the axial direction. This tapered ferrule-shaped projection 336 is radially spaced apart from and magnetically coupled with outer cylindrical surface 290 of the armature sleeve 274 of the armature 222, by a radial air gap 338 therebetween, so as to form a magnetic flux path shunt.

[0043] Alternatively, in lieu of providing the annular shunt projection 336 on the distal end of the generally axial portion 322 of magnetic pole piece 306, an equivalent shunt structure may be provided by configuring the top generally circular surface circular surface 294 of the armature 222 with a tapered annular projection, that is spaced apart from and magnetically coupled with the distal end 334 of the generally axial portion 322 of the magnetic pole piece 306. In either case, the ferrule-shaped projection allows for relative axial translation between the movable armature 222 and the magnetic pole piece 306, as the moveable armature 222 is axially translated.

[0044] The magnetic pole piece 306 further includes generally annular sleeve pole piece portion 340 that is continuous with the first, generally axial portion 322 and includes relatively thin portion 342 that is radially spaced apart from the lower end of the pole piece portion 322, and becomes rapidly saturated by the magnetic field generated by the solenoid coil 326. To provide for fluid leakage containment, the annular sleeve pole piece portion 340 is made effectively mechanically solid with the main pole piece portion 322.

[0045] In the embodiment of FIG. 2, this is accomplished by configuring the first, generally axial portion 322 of the pole piece 306 as a generally cylindrical component and externally threaded as shown at 344, so that it may be threaded into a threaded interior cylindrical bore 346 of the annular sleeve portion 340 of the pole piece 306. A fluid seal is provided by means of an O-ring 348 captured within an annular groove 350 formed within the cylindrical sidewall of axial pole piece portion 322. In an alternative configuration, the main and annular pole piece portions may be formed of the same magnetic pole piece element, so as to obviate the need for an O-ring.

[0046] The relatively thin segment 342 of the annular pole piece portion 340 extends to and is solid with the radially inward projecting portion 316 of the pole piece 306. For mechanical alignment, the cylindrical shape of the radial air gap 320 constrains movement of the armature 222 in the axial direction only. This serves to prevent potential off-axis distortion of the suspension springs 264 and 270, so that proper operation of the valve is not impaired. Axial alignment is reinforced by the fact that the radial air gap 320 is radially aligned with and axially offset from the shunt radial air gap 338, thereby providing a pair of axially displaced coaxial guide air-bushings that prevent off-axis play between the moveable armature 222 and the fixed magnetic pole piece 306.

[0047] However, as described in the '______ application, unlike conventional solenoid structures, the integral pole piece and support architecture does not require a non-magnetic material in the magnetic flux flow path. This reduces manufacturing and hardware complexity and cost associated with solenoid structures having non-ferromagnetic materials as part of flux path containment and pole piece—armature alignment.

[0048] As pointed out briefly above, the fluid pressure balancing mechanism of the invention takes advantage of this fluid leakage containment functionality of the integrated magnetic pole piece 306, by incorporating an additional fluid flow restriction mechanism between the armature cavity 256 and the fluid inlet cavity 218, and providing an auxiliary fluid communication path between the armature cavity 256 and fluid exit port 206. In order to realize a compact structure, this auxiliary communication path is readily implemented without the need for any additional components, such as the connecting rod and additional diaphragm components employed in the assembly of FIG. 1, described above.

[0049] Instead, as shown in FIG. 2, an auxiliary axial bore 223 is formed through the armature 222, so as to provide fluid communication between the valve bore 212 (which is in fluid communication with the fluid exit port 206) and the axial air gap 335 between the lower distal end 334 of the axial portion 322 of the magnetic pole piece 306. Since the axial air gap 335 is in fluid communication with the upper (fluid leakage-contained) cavity structure that includes the cavity 341 and armature cavity 256, it couples the pressure P2 supplied via the auxiliary bore 223 from the fluid exit port 206 to the top side of fluid restriction (diaphragm) 242.

[0050] As described above, the fluid restricting diaphragm 242 has an annular area A242 that is substantially the same as or very close to that of the area A214 of the orifice 214 of bore 212. As a result, any upward force imparted by the pressure P2 at the fluid exit port 206 against the bottom face 228 of the poppet 220 will be countered by ‘downward’ force imparted by the pressure P2, that has coupled through the auxiliary bore to the top of the diaphragm 242. This serves to effectively neutralize the contribution of the pressure P2 to the position of the valve poppet 220 relative to valve seat 216.

[0051] In a complementary fashion, the pressure P1 at the fluid inlet port 204 is balanced as a result of a downward force (as viewed in FIG. 2) imparted by the inlet fluid pressure P1 against the poppet 220 being substantially the same as the ‘upward’ force imparted by the pressure P1 against the bottom of diaphragm 242.

[0052] FIG. 3 diagrammatically illustrates a second embodiment of the invention, in which the fluid restriction mechanism is implemented by means of an O-ring 360 inserted into an annular groove 362 of an armature support member 364. Similar to the diaphragm 242 of the embodiment of FIG. 2, O-ring 360 has an annular area A360 that is substantially the same as or very close to that of the area A371 of an orifice 371 of a valve bore 370.

[0053] In this embodiment, and also that of FIG. 4, to be described, the armature/poppet assembly is shown as being configured as a single integrated armature/poppet element 366. This armature/poppet element 366 contains an auxiliary axial bore 368, that provides fluid communication between valve bore 370 and the axial air gap 335 between the lower distal end 334 of the axial portion 322 of the magnetic pole piece 306.

[0054] Moreover, as described above, in the embodiments of FIG. 3 and FIG. 4, a valve seat 376 is shown as having the above-described alternative adjustable configuration, being installed in a threaded portion 372 of a valve seat installation bore 374 in the valve body. The valve seat 376 is maintained in a fluid sealed condition within the valve installation bore 374 by a pair of O-rings 378 and 380.

[0055] Also, a single spiral-configured suspension spring 382 is used to support the armature-poppet element 366. In the embodiment of FIG. 3, the suspension spring 382 is held against an armature sleeve 384 by a retention washer 386. A generally outer circumferential region 388 of suspension spring 382 is captured between support member 364 and an interior ledge surface portion 390 of the cup-shaped portion 304 of the ferromagnetic pole piece 306.

[0056] The pressure-balancing function provided by the O-ring 360 in the embodiment of FIG. 3 is similar to that of the diaphragm 242 in the embodiment of FIG. 2, in that an upward force imparted by the pressure P2 at the fluid exit port against the bottom of the armature-poppet 366 will be countered by ‘downward’ force imparted by the pressure P2, that has coupled through the auxiliary bore 368 to the top of the O-ring 360. Also, the pressure P1 at the fluid inlet port 204 is balanced as a result of a downward force imparted by the inlet fluid pressure P1 against armature-poppet 366 being substantially the same as the ‘upward’ force imparted by the pressure P1 against the bottom of the O-ring 360.

[0057] FIG. 4 diagrammatically illustrates a third embodiment of the invention, in which the fluid restriction mechanism is implemented without a captured element, such as the diaphragm 242 in the embodiment of FIG. 2 or the O-ring 360 in the embodiment of FIG. 3. Instead, the restriction is defined by the geometry of a very narrow annular aperture 400, that is formed between the outer cylindrical surface 402 of the armature-poppet 366 and the inner cylindrical surface 404 of an armature insertion bore 405 through the surrounding support member 364.

[0058] In this embodiment, the geometric parameters of the armature-poppet 366 (including its outer diameter and auxiliary internal bore size), and those of the armature insertion bore 405 through the support member 364, are defined such as to limit or restrict ‘upward’ fluid flow therethrough of the inlet pressure P1 and ‘downward’ fluid flow therethrough of the outlet pressure P2, in a manner that is proximate the force imparted by these pressures on opposite sides of the armature-poppet 366 relative to the valve orifice 371. Again, the net result is to neutralize the contribution of each of the fluid inlet and outlet pressures P1 and P2 on the position of the armature-poppet relative to the valve seat.

[0059] As will be appreciated from the foregoing description, the solenoid-actuated valve assembly of the invention not only effectively balances inlet and outlet pressures of the fluid ports of the valve, but is implemented with reduced hardware complexity. The incorporation of a fluid flow restriction between the armature cavity and the fluid inlet cavity, plus a fluid communication path through the valve closing assembly, provides a highly integrated structure that reduces overall size and cost of assembly.

[0060] While I have shown and described several embodiments in accordance with the present invention, it is to be understood that the same is not limited thereto but is susceptible to numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to be limited to the details shown and described herein but intend to cover all such changes and modifications as are obvious to one of ordinary skill in the art.

Claims

1. A solenoid-actuated valve assembly comprising: a solenoid coil adapted to generate a magnetic field, and having a longitudinal axis and a bore coaxial therewith; an axially movable armature of magnetic material, supported within an armature cavity for axial translation along said longitudinal axis; a magnetic pole piece disposed within the bore of said solenoid coil and being magnetically coupled with said axially movable armature; a valve unit, mechanically coupled with said axially movable armature, and having a fluid cavity coupled in fluid communication with a fluid inlet port to which fluid is applied at a first fluid pressure, and a fluid exit port from which said fluid is output at a second fluid pressure, and containing a valve seat therebetween, which is adapted to be closed by a valve closing assembly that includes a valve poppet coupled with said moveable magnetic armature, so as to regulate fluid flow between said fluid inlet port and said fluid exit ports; and a fluid pressure balancing arrangement adapted to compensate for said first and second fluid pressures being exerted against said valve poppet, and comprising a fluid flow restriction between said armature cavity and said fluid cavity, and a fluid communication path through said valve closing assembly and providing fluid communication between said fluid exit port and said armature cavity.

2. The solenoid-actuated valve assembly according to claim 1, wherein said fluid flow restriction comprises a generally annular-shaped passageway adjacent to said valve closing assembly and extending between said armature cavity and said fluid cavity.

3. The solenoid-actuated valve assembly according to claim 1, wherein said fluid flow restriction comprises a fluid seal element, coupled between said valve closing assembly and said valve unit in a manner that prevents fluid communication between said inlet port and said armature cavity.

4. The solenoid-actuated valve assembly according to claim 3, wherein said fluid seal element comprises a diaphragm.

5. The solenoid-actuated valve assembly according to claim 3, wherein said fluid seal element comprises an O-ring.

6. The solenoid-actuated valve assembly according to claim 1, wherein said magnetic pole piece includes a first, generally axial portion having an end thereof axially spaced apart from and magnetically coupled with said axially movable armature, a second, generally annular portion continuous with said first, generally axial portion of said magnetic pole piece and being spaced apart from said end thereof, and a third, generally radial portion continuous with said second, generally annular portion, and being magnetically coupled with said axially moveable armature.

7. The solenoid-actuated valve assembly according to claim 6, wherein said third, generally radial portion of said magnetic pole piece is solid with a housing for said solenoid coil, so that support for and axial alignment of first portion of said magnetic pole piece relative to said axially moveable armature is provided by said second and third portions of said magnetic pole piece continuous therewith, and is exclusive of a non-magnetic element.

8. The solenoid-actuated valve assembly according to claim 7, wherein said second and third portions of said magnetic pole piece are configured to form, with said housing, a generally annular space that receives a portion of said solenoid coil.

9. The solenoid-actuated valve assembly according to claim 6, wherein said third portion of said magnetic pole piece includes a radially inwardly projecting portion that is adjacent to but radially spaced apart from and magnetically coupled with said axially moveable armature.

10. The solenoid-actuated valve assembly according to claim 6, wherein said third, generally radial portion of said magnetic pole piece is attached to said valve unit.

11. The solenoid-actuated valve assembly according to claim 6, wherein said first and second portions of said magnetic pole piece are configured to be relatively axially adjustable.

12. The solenoid-actuated valve assembly according to claim 6, wherein said second and third portions of said magnetic pole piece are separate portions of the same pole piece element.

13. The solenoid-actuated valve assembly according to claim 11, wherein said first and second portions of said magnetic pole piece are provided with a fluid seal therebetween.

14. The solenoid-actuated valve assembly according to claim 6, wherein said magnetic pole piece is configured to form a magnetic flux shunt path with said axially moveable armature.

15. The solenoid-actuated valve assembly according to claim 1, wherein said axially moveable armature is spring-supported outside said bore for axial translation relative to said magnetic pole piece.

16. A solenoid-actuated valve assembly comprising a a solenoid coil having a longitudinal axis and a solenoid cavity coaxial therewith, said solenoid coil producing a magnetic field, a magnetic pole piece including an axial portion thereof supported within said solenoid cavity exclusive of the use of non-magnetic material, and an armature axially translatable relative to and axially and radially magnetically coupled with said magnetic pole piece, while being supported with said magnetic pole piece by a fluid flow restriction that restricts fluid flow with said solenoid cavity and having an internal bore therethrough providing fluid communication with said solenoid cavity.

17. The solenoid-actuated valve assembly according to claim 16, further including a valve unit, mechanically coupled with said armature, and having a fluid cavity coupled in fluid communication with a fluid inlet port to which fluid is applied at a first fluid pressure, and a fluid exit port from which said fluid is output at a second fluid pressure, and containing a valve seat therebetween, which is adapted to be closed by a valve closing assembly that includes a valve poppet coupled with said moveable magnetic armature, so as to regulate fluid flow between said fluid inlet port and said fluid exit ports, and wherein said fluid flow restriction is configured to balance fluid pressures at the fluid inlet and exit ports applied to the opposite sides of said fluid flow restriction, in a manner that is complementary to the fluid pressures applied to opposite sides of said valve poppet, thereby effectively neutralizing the effects of fluid pressure on poppet position.

18. The solenoid-actuated valve assembly according to claim 17, wherein said fluid flow restriction comprises a generally annular-shaped passageway adjacent to said valve closing assembly and extending between said armature cavity and said fluid cavity.

19. The solenoid-actuated valve assembly according to claim 17, wherein said fluid flow restriction comprises a fluid seal element.

20. The solenoid-actuated valve assembly according to claim 19, wherein said fluid seal element comprises one of a diaphragm and an O-ring.