A pulse-width-modulated solenoid valve has a body provided with an elongated chamber. The body has inlet and outlet openings communicating with the chamber, and has a seat surrounding the inlet opening and arranged to face into the chamber. An armature is mounted in the chamber for movement therealong toward and away from the seat. A coil is mounted on the body, and is adapted to be selectively energized to move the armature in one direction relative to the body. A return spring is arranged to urge the armature to move in the opposite direction relative to the body. The improvement provides a valve element which is mounted for movement with the armature toward and away from the seat, but also mounted for movement relative to the armature when the element engages the seat, such that the mass of the armature will not exert a substantial force against the seat. According to the improvement, the operating life of the valve may be greatly extended.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to the field of solenoid valves, 
and, more particularly, to an improved pulse-width-modulated (PWM) 
solenoid valve having a long service life. 
2. Description of the Prior Art 
Solenoid valves are, of course, well known. Generally, these valves have a 
poppet member mounted within a body for movement toward and away from a 
fixed seat. An armature is normally connected to the poppet member. The 
poppet member is typically biased to move to a closed position by a return 
spring. However, it has been Applicant's experience that such solenoid 
valves do not have a long life when controlled by a pulse-width-modulated 
technique, wherein the solenoid valve is typically opened and closed two 
or three hundred times each second. One reason for limited life is that 
the combined mass of the armature and poppet impacts repeatedly against 
the seat, causing deformation which adversely affects valve leakage and 
flow characteristics. This is believed to substantially shorten the 
operating life of the valve. Other details of prior art PWM solenoid 
valves are shown and described in Technical Bulletin 151, 
"Electropneumatic Servoactuation: An Alternative to Hydraulics for Some 
Low Power Applications", Moog Inc. (1984). 
SUMMARY OF THE INVENTION 
The present invention provides an improvement for use in a 
pulse-width-modulated solenoid valve. Such a valve has a body provided 
with a chamber, and further provided with inlet and outlet openings 
communicating with this chamber. The body also has a fixed seat 
surrounding one of these openings, and arranged to face into the chamber. 
An armature is mounted in the chamber for movement toward and away from 
the seat. A coil is mounted on the body, and is adapted to be momentarily 
energized to move the armature in one direction relative to the body. 
Return means, such as a return spring, is operatively arranged to move the 
armature in the opposite direction relative to the body when the coil is 
de-energized. The improvement broadly comprises: a poppet valve element 
generally mounted for movement with the armature toward and away from the 
seat, and also mounted for specific movement relative to the armature such 
that when the element engages the seat, the mass of the armature will not 
exert a substantial force against the seat. According to the improvement, 
the operating life of the seal between the element and seat may be greatly 
extended. 
Accordingly, the general object of the invention is to provide an improved 
solenoid valve. 
Another object is to provide an improvement for use in a 
pulse-width-modulated solenoid valve. 
Still another object is to provide an improvement in a 
pulse-width-modulated solenoid valve, which improvement affords the 
capability of greatly extending the operative life of the valve. 
These and other objects and advantages will become apparent from the 
foregoing and ongoing written specification, the drawings, and the 
appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
At the outset, it should be clearly understood that like reference numerals 
are intended to identify the same structural elements, portions or 
surfaces consistently throughout the several drawing figures, as such 
elements, portions or surfaces may be further described or explained by 
the entire written specification, of which this detailed description is an 
integral part. Unless otherwise indicated, the drawings are intended to be 
read (e.g., cross-hatching, arrangement of parts, etc.) together with the 
specification, and are to be considered a portion of the entire "written 
description" of this invention, as required by 35 U.S.C. .sctn.112. As 
used in the following description, the terms "horizontal", "vertical", 
"left", "right", "up" and "down", as well as adjectival and adverbial 
derivatives thereof (e.g., "horizontally", "rightwardly", "upwardly", 
etc.), simply refer to the orientation of the illustrated structure as the 
particular drawing figure faces the reader. Similarly, the terms 
"inwardly" and "outwardly" refer to the orientation of a surface relative 
to its axis of elongation, or axis of rotation, as appropriate. Unless 
otherwise indicated, the word "fluid" is intended to include both a liquid 
and a gas. 
The present invention provides an improved pulse-width-modulated (PWM) 
solenoid valve, of which two presently-preferred embodiments are 
disclosed. The first embodiment is illustrated in FIGS. 1-3, and the 
second is shown in FIGS. 4-6. For the convenience of the reader, these two 
embodiments will be described seriatim herebelow. 
First Embodiment (FIGS. 1-3) 
Referring now to FIG. 1, a first embodiment of the improved PWM solenoid 
valve is generally indicated at 10. Valve 10 is shown as broadly including 
a multi-part assembled body, generally indicated at 11, provided with a 
horizontally-elongated chamber 12, with inlet and outlet openings 13, 14, 
respectively, communicating with this chamber, and with a seat 15 facing 
rightwardly into the chamber; an armature 16 mounted in the chamber for 
horizontal sliding movement therealong toward and away from the seat; a 
coil 18 mounted on the body and adapted to be momentarily energized by 
suitable means (not shown) to selectively move the armature rightwardly 
relative to the body; and return means, such as a return spring 19, for 
continuously urging the armature to move leftwardly relative to the body. 
The improvement broadly includes: a valve element, such as poppet member 
20, mounted for general movement with the armature toward and away from 
the seat, but also specifically mounted for movement relative to the 
armature such that when the poppet member moves leftwardly to engage the 
seat, the mass of the armature will be effectively separated or uncoupled 
from the mass of the poppet. By this arrangement, the mass of the armature 
will not impact against the seat, and the operational life of the seal 
formed between the seat and the poppet can be greatly extended. 
Still referring principally to FIG. 1, the assembled body is shown as 
broadly including an outer part 21, an inner part 22, a seat member 23 
mounted within outer part 21, a return spring adjustment member 24, a 
retaining plate 25 engaging the inner part, and a retaining ring 26 
engaging the retaining plate and the outer part. 
More particularly, the body outer part 21 is depicted as being a stepped 
tubular member, generated about horizontal axis x--x, having an annular 
vertical left end face 28; an annular vertical right end face 29; and an 
inner surface which sequentially includes (from left to right): an 
internally-threaded portion 30 extending rightwardly from left end face 
28, a rightwardly-facing annular vertical surface 31, an inwardly-facing 
horizontal cylindrical surface 32, an inwardly- and rightwardly-facing 
frusto-conical surface 33, an inwardly-facing horizontal cylindrical 
surface 34, a rightwardly-facing annular vertical surface 35, an 
inwardly-facing horizontal cylindrical surface 36, a rightwardly-facing 
annular vertical surface 38, and an internally-threaded portion 39 
continuing rightwardly therefrom to join right end face 29. The outer 
surface of body outer part generally parallels the inner surface, just 
described, but is not deemed material to an understanding of the 
improvement. Hence, a description of such outer surface has been omitted 
in the interest of clarity. However, a vertical hole 40 is shown as 
extending diametrically through an intermediate portion of the outer part 
to form a portion of the outlet opening 14. 
The body inner part 22 is also shown as being a horizontally-elongated 
stepped tubular member, also generated about axis x--x, which has been 
inserted into the open right end of the body outer part. Specifically, the 
inner art has an annular vertical left end face 41; an annular vertical 
right end face 42; and an outer surface which sequentially includes (from 
left to right): an outwardly-facing horizontal cylindrical surface 43 
extending rightwardly from left end face 41, a leftwardly-facing annular 
vertical surface 44, an outwardly-facing horizontal cylindrical surface 
45, a rightwardly-facing annular vertical surface 46, an outwardly-facing 
horizontal cylindrical sruface 48, a rightwardly-facing annular vertical 
surface 49, and an outwardly-facing horizontal cylindrical surface 50 
continuing rightwardly therefrom to join right end face 42. The inner 
surface of this body inner part sequentially includes (from left to 
right): an inwardly-facing horizontal cylindrical surface 51 extending 
rightwardly from left end face 41, a leftwardly-facing annular vertical 
surface 52, an inwardly-facing horizontal cylindrical surface 53, and an 
internally-threaded portion 54 continuing rightwardly therefrom to join 
right end face 42. Inner part 22 has been inserted leftwardly into the 
open right end of outer part 21 such that inner part surfaces 41, 43, 44, 
45 are arranged to face outer part surfaces 33, 34, 35, 36, respectively. 
An O-ring 55 seals the joint between surfaces 34, 43. 
Seat member 23 is shown as being a specially-configured 
horizontally-elongated tubular member operatively mounted within the left 
marginal end portion of the body outer part. Specifically, the seat member 
has an annular vertical left end face 56; an annular verical right end 
face 58; and an outer surface which sequentially includes (from left to 
right): an externally-threaded portion 59 extending rightwardly from left 
end face 56, a leftwardly-facing annular vertical surface 60, an 
outwardly-facing horizontal cylindrical surface 61, a rightwardly-facing 
annular vertical surface 62, an outwardly-facing horizontal cylindrical 
surface 63, a leftwardly-facing annular vertical surface 64, an 
outwardly-facing horizontal cylindrical surface 65, a rightwardly-facing 
annular vertical surface 66, and an outwardly-facing horizontal 
cylindrical surface 68 continuing rightwardly therefrom to join right end 
face 58. The inner surface of seat member 23 sequentially includes (from 
left to right): an inwardly-facing horizontal cylindrical surface 69 
extending rightwardly from left end face 56, an inwardly-and 
leftwardly-facing frusto-conical surface 70, an inwardly-facing horizontal 
cylindrical surface 71, a rightwardly-facing annular vertical seat 15, an 
outwardly-facing horizontal cylindrical surface 72 extending leftwardly 
therefrom (FIG. 3), a rightwardly-facing annular vertical surface 73, and 
an inwardly-facing horizontal cylindrical surface 74 continuing 
rightwardly therefrom to join right end face 58. Surfaces 71, 15, 72 
define an integrally-formed tubular collar which extends rightwardly into 
chamber 12, and which collar terminates in a rightwardmost seat 15. 
Inclined holes 75, 75 communicate inner surfaces 73, 74 with outer 
surfaces 63, 64, and form another portion of the outlet opening. The seat 
member is threaded into engagement with the body left part such that seat 
member surfaces 60, 61 are arranged to face outer part surfaces 31, 32, 
respectively. An O-ring 76 seals the joint between surfaces 61, 32. The 
inlet opening 13, is bounded by surfaces 69, 70, 71. 
The return spring adjustment member 24 is a specially-configured solid 
member, also generated about axis x--x, which is operatively mounted 
within the right marginal end portion of the body inner part. Member 24 
has a circular vertical left end face 77, a circular vertical right end 
face 78, and an outer surface which sequentially includes (from left to 
right): an outwardly-facing horizontal cylindrical surface 79 extending 
rightwardly from left end face 76, a leftwardly-facing annular vertical 
surface 80, an outwardly-facing horizontal cylindrical surface 81, a 
rightwardly-facing annular vertical surface 82, and an externally-threaded 
portion 83 continuing rightwardly therefrom to join right end face 78. A 
slot 84 extends leftwardly into member 24 from its right end face to 
accept and accommodate a suitable turning tool, such as a screwdriver, by 
which member 24 may be selectively rotated relative to the body inner 
part. The angular position of the adjusting member 24 relative to the body 
inner part may be fixed by selectively tightening a locknut 85, which is 
threaded onto the adjustment member and is arranged to be tightened 
against inner part right end face 42. Surfaces 81, 53 are arranged in 
closely-spaced facing relation, and the joint therebetween is sealed by 
means of an O-ring 86. Thus, the adjustment member may be selectively 
rotated relative to the body inner part to vary the position of its 
surface 80 relative to the body inner part. 
Retaining plate 25 is shown as being an annular ring-like member, somewhat 
resembling a flat washer, and surrounds the rightwardly-extending stem of 
the body inner part. Specifically, the retaining plate has an annular 
vertical left end face 88 arranged to abut inner part surface 49, has an 
annular vertical right end face 89, has a horizontal cylindrical outer 
surface 90 arranged to face outer part surface 36, and has a horizontal 
cylindrical inner surface 91 arranged to face inner part surface 50. 
Retaining plate 25 is held in this position, preventing unintended 
separation of the body inner and outer parts, by means of retaining ring 
26. Ring 26 is an annular ringlike member having an externally-threaded 
portion 92 arranged in mating engagement with body outer part threaded 
portion 39. The retaining plate is further shown as being provided with an 
eccentrically-positioned horizontal through-hole 93 to accommodate passage 
of the electrical conductors leading to the coil. The annular recess 
defined between the right marginal end portion of the body outer part, the 
retaining ring, the retaining plate, and the right marginal end portion of 
the body inner part, is shown as being filled with a suitable sealant, 
such as a potting compound 94. 
The coil 18 is shown as being an annular member wound around a dielectric 
bobbin 95. Bobbin 95 is shown as having an annular vertical left end face 
and an inwardly-facing horizontal cylindrical inner surface, arranged to 
face inner part surfaces 46, 48, respectively. The annular vertical right 
end face of the bobbin is engaged by the retaining plate 25, and the 
opening 93 about the coil conductors and is also filled with the potting 
compound. 
As best shown in FIG. 2, armature 16 is shown as being a 
specially-configured annular member operatively arranged within chamber 12 
for horizontal sliding movement between body surfaces 66, 52. 
Specifically, the armature has an annular vertical left end face 96; an 
annular vertical right end face 98; and an outwardly-facing horizontal 
cylindrical outer surface 99 extending therebetween. The inner surface of 
the armature sequentially includes (from left to right): an inwardly- and 
leftwardly-facing frusto-conical surface 100 extending rightwardly from 
left end face 96, and another leftwardly- and inwardly-facing 
frusto-conical surface 101 continuing rightwardly therefrom to join right 
end face 98. An upwardly- and rightwardly-inclined hole 102 communicates 
armature surfaces 101, 98, and functions to provide a flow passage for any 
fluid trapped between armature right end face 98 and body inner part 
surface 52. Armature outer surface 99 is arranged to slidably engage inner 
part surface 51. Persons skilled in this art will readily appreciate that 
the radial clearance between armature outer surface 99 and body surface 51 
forms a non-working radial air gap of substantially constant reluctance. 
However, the armature right end face 98 and body surface 52 form a working 
air gap of variable reluctance, depending upon the spacing therebetween, 
through which coil flux must pass. Thus, the armature is mounted on the 
body for horizontal sliding movement therealong, with armature surfaces 
96, 98 arranged to face body surfaces 62, 52, respectively. When the coil 
is energized, armature 16 will move rightwardly relative to the body and 
toward the position shown in FIG. 2. 
Still referring principally to FIG. 2, the poppet 20 is shown as being a 
specially-configured horizontally-elongated solid member, also generated 
about axis x--x. Specifically, the poppet has a circular vertical left end 
face 105; a circular vertical right end face 106; and an outer surface 
which sequentially includes (from left to right): a leftwardly- and 
outwardly-facing frusto-conical surface 108 extending rightwardly from 
left end face 105, an outwardly-facing horizontal cylindrical surface 109, 
a rightwardly-facing annular vertical surface 110, an outwardly-facing 
horizontal cylindrical surface 111, a leftwardly-facing annular vertical 
surface 112, an outwardly-facing horizontal cylindrical surface 113, a 
rightwardly-facing annular vertical surface 114, and an outwardly-facing 
horizontal cylindrical surface 115 continuing rightwardly therefrom to 
join right end face 106. Poppet surfaces 109, 113 are arranged to slidably 
engage body surfaces 74, 53, respectively. Hence, the poppet is slidably 
mounted within the chamber for guided horizontal sliding movement relative 
to the body toward and away from seat surface 15. A portion of poppet 
surface 112 is arranged to selectively engage right end face 98 of the 
armature. 
The return spring 19 is shown as being a compressed coil spring. The right 
end of spring 19 engages adjusting member surface 80, and the left end of 
this spring engages poppet surface 114. Thus, return spring 19 
continuously urges poppet 20 to move leftwardly into fluid-tight sealing 
engagement with seat 15. 
When coil 18 is de-energized, return spring 19 will expand to selectively 
displace the poppet 20 and the armature 16 leftwardly relative to the 
body. The poppet will move leftwardly to abut seat surface 15, and this 
will occur before armature left end face 96 abuts body surface 66. When 
the coil is energized, the coil flux will pull the armature rightwardly 
toward the position shown in FIG. 2. As this occurs, the armature right 
end face 98 will engage poppet surface 112, and will selectively move the 
poppet member rightwardly off seat 15. When the coil is subsequently 
de-energized, return spring 19 will again expand to displace the poppet 
and armature leftwardly until poppet surface 105 again sealingly engages 
seat surface 15. However, it should be clearly noted that the poppet will 
sealingly engage seat 15 before armature left end face 96 abuts body 
surface 66. Hence, only the momentum of the mass of the poppet will impact 
seat 15, with the armature being permitted some additional over-travel 
prior to engaging body surface 66. Thus, when the coil is energized, the 
armature and poppet member move rightwardly together. When the coil is 
de-energized, the armature and poppet initially move leftwardly together 
until the poppet engages seat 15. However, the armature may travel an 
additional distance before abutting body surface 66. The significance of 
this is that the mass of the armature is effectively separated, isolated 
or uncoupled from the mass of the poppet when the poppet engages the seat. 
This separation of the mass of the armature from the mass of the poppet is 
believed to greatly extend the operating life of the seal between the 
poppet and seat, particularly when the repetition rate of the electrical 
signal supplied to the coil is high. When poppet surface 105 sealingly 
engages seat 15, flow from the inlet opening 13 to the outlet opening 14 
will be blocked. However, when the coil has been energized to selectively 
displace the armature and poppet rightwardly, fluid may flow through the 
inlet opening 13, through the now-uncovered opening between the seat and 
the poppet, and through the outlet opening 14. 
If desired, the tubular collar, upon which the seat is provided, may be 
formed of a relatively-hard material, and the poppet member may be formed 
of a relatively-soft material. This arrangement will insure that the 
collar will "coin" an appropriately-configured indentation in the poppet 
when the repetition rate is high, without adversely affecting the 
integrity of the fluid-tight seal therebetween. Likewise, the 
relatively-narrow annular seating surface formed by the tubular collar can 
undergo minor deformation during the coining process without materially 
changing the apparent valve orifice size, which is determined, in part, by 
the effective diameter of the seat. 
Second Embodiment (FIGS. 4-6) 
A second embodiment of an improved PWM solenoid valve incorporating the 
present improvement is shown in FIGS. 4-6. 
This second embodiment, generally indicated at 120, is shown as broadly 
including a multi-part assembled body, generally indicated at 121, 
provided with a horizontally-elongated chamber 122, inlet and outlet 
openings 123, 124, respectively, communicating with this chamber, and a 
seat 125 (FIG. 5) facing rightwardly into this chamber; an armature 126 
mounted in the chamber for horizontal sliding movement therealong toward 
and away from the seat; a coil 128 mounted on the body and adapted to be 
selectively energized by suitable means (not shown) to move the armature 
rightwardly relative to the body; and return means; such as a return 
spring 129, for continously urging the armature to move leftwardly 
relative to the body. In this embodiment, the improvement broadly 
includes: a ball valve element 130, a plunber member 131, and a cushioning 
means 132 operatively arranged between the armature and the plunger 
member. As with the first embodiment, the salient feature of this second 
embodiment is that when the ball, plunber and armature move leftwardly 
toward the seat, the mass of the armature will be effectively separated or 
uncoupled from the combined mass of the plunger and ball when the ball 
sealingly engages the seat. Hence, the operational life of the seal formed 
between the ball and the seat can be greatly extended. 
The assembled body is shown as includiing an outer part 133, an inner part 
134, a seat member 135, a return spring adjustment member 136, and a 
plunger guide 138. 
The body outer part 133 is a specially-configured horizontally-elongated 
member, generated about horizontal axis x--x, and has annular vertical 
left and right end faces 139, 140, respectively. The inner surface of body 
part 133 sequentially includes (from left to right): an 
internally-threaded portion 141 extending rightwardly from left end face 
139, an inwardly-facing horizontal cylindrical surface 142, a 
rightwardly-facing annular vertical surface 143, an outwardly-facing 
horizontal cylindrical surface 144 extending leftwardly from surface 143, 
a rightwardly-facing annular vertical surface 145, an inwardly-facing 
horizontal cylindrical surface 146, and an internally-threaded portion 148 
continuing rightwardly therefrom to join right end face 140. The outer 
surface of body outer part 133 is not deemed material to an understanding 
of the present improvement, and a description thereof has been omitted. A 
vertical hole 149 extends diametrically through the body outer part, and 
forms a portion of the outlet opening 124. 
The body inner part is shown as being a horizontally-elongated tubular 
member, also generated about axis x--x, which has been inserted leftwardly 
into the open right end of the body outer part. Specifically, the body 
inner part 134 has an annular vertical left end face 150; an annular 
vertical right end face 151; and an inner surface which sequentially 
includes (from left to right): an inwardly-facing horizontal cylindrical 
surface 152 extending rightwardly from left end face 150, a 
rightwardly-facing annular vertical surface 153, and an 
internally-threaded portion 154 continuing rightwardly therefrom to join 
right end face 151. The outer surface of inner part 134 sequentially 
includes (from left to right): an outwardly-facing horizontal cylindrical 
surface 155 extending rightwardly from left end face 150, a 
leftwardly-facing annular vertical surface 156, an outwardly-facing 
horizontal cylindrical surface 158, a rightwardly-facing annular vertical 
surface 159, and an outwardly-facing horizontal cylindrical surface 160 
continuing rightwardly therefrom to join right end face 151. Inner part 
surface 158 is arranged in closely-spaced facing relation to outer part 
surface 146. The inner part is further provided with an 
eccentrically-positioned horizontal through-hole 161 to accommodate 
passage of the conductors leading to coil 128. The body inner part 134 is 
held in this position by an annular retaining ring, generally indicated at 
162, having an externally-threaded portion 163 matingly engaging threaded 
portion 148, and having a leftwardly-facing annular vertical surface 164 
arranged to abut inner part surface 159. 
The seat member 135 is shown as being a horizontally-elongated member, also 
generated about horizontal axis x--x, and operatively received in the left 
marginal end portion of the body outer part. Specifically, seat member 135 
has an annular vertical left end face 165, and an annular vertical right 
end face 166. The inner surface of seat member 135 sequentially includes 
(from left to right): an inwardly-facing horizontal cylindrical surface 
168 extending rightwardly from left end face 165; an inwardly-and 
leftwardly-facing frusto-conical surface 169, an inwardly-facing 
horizontal cylindrical surface 170, an inwardly- and leftwardly-facing 
frusto-conical surface 171 (FIG. 6), an inwardly-facing horizontal 
cylindrical surface 172, and a rightwardly- and inwardly-facing 
frusto-conical seat surface 125 continuing rightwardly therefrom to join 
right end face 166. Surface 125 forms the seat toward and away from which 
valve element 130 moves. The outer surface of seat member 135 sequentially 
includes (from left to right): an externally-threaded portion 174 
extending rightwardly from left end face 165, an outwardly-facing 
horizontal cylindrical surface 175, a rightwardly-facing annular vertical 
surface 176, and an outwardly-facing horizontal cylindrical surface 178 
(FIG. 6) continuing rightwardly therefrom to join right end face 166. Seat 
member surface 175 is arranged in closely-spaced facing relation to body 
outer part surface 142, and the joint therebetween is sealed by 
axially-spaced O-rings 179, 180. An annular groove, generally indicated at 
181, extends radially into seat member 135 from surface 175 between 
O-rings 179, 180. Groove 181 communicates with an L-shaped passageway. 
This passageway includes a blind vertical hole 182 drilled upwardly into 
seat member 135, and intersected by a horizontal hole 183 drilled 
leftwardly into seat member 135 from its right end face 166. A vertical 
hole 184 communicates outer surface 178 with inner surface 170. 
As best shown in FIGS. 5 and 6, a ball retainer 185 is shown as being 
operatively mounted on the right marginal end portion of seat member 135. 
Retainer 185 is shown as being a specially-configured 
horizontally-elongated member, also generated about axis x--x, having 
annular vertical left and right end faces 186, 188, respectively. As best 
shown in FIG. 6, the inner surface of retainer 185 sequentially includes 
(from left to right): an inwardly-facing horizontal cylindrical surface 
189 extending rightwardly from left end face 186 and arranged to face seat 
member surface 178, a leftwardly-facing annular vertical surface 190 
arranged to abut seat member end face 166, an inwardly-facing horizontal 
cylindrical surface 191, a leftwardly-facing annular vertical surface 192, 
and an inwardly-facing horizontal cylindrical surface 193 continuing 
rightwardly therefrom to join right end face 188. Adverting now to FIG. 5, 
annular groove extends radially into the ball retainer from surface 193 to 
receive and accommodate a ring-like annular seal 194, which sealingly and 
slidably engages the left marginal rod end portion of plunger 131. The 
outer surface of the ball retainer is shown as sequentially including 
(from left to right): an outwardly-facing horizontal cylindrical surface 
195 extending rightwardly from left end face 186, a rightwardly- and 
outwardly-facing frusto-conical surface 196, a rightwardly-facing annular 
vertical surface 198, and an outwardly-facing horizontal cylindrical 
surface 199 continuing rightwardly therefrom to join right end face 188. 
Surfaces 166, 191, 192 form an annular chamber 200 about the seat 125 and 
ball 130. An inclined hole 201 communicates retainer surfaces 192, 193 
such that the fluid pressure within left chamber 200 will also exist in 
the right chamber 207 between the ball and seal 194. 
The ball valve element 130 is operatively arranged within the ball retainer 
for movement toward and away from seat surface 125. 
Adverting now to FIG. 4, the return spring adjustment member 136 is shown 
as being a specially-configured member operatively mounted within the 
right marginal end portion of body inner part 134. Specifically, 
adjustment member 136 is shown as being a horizontally-elongated tubular 
member, generated about axis x--x, having annular vertical left and right 
end faces 202, 203, respectively. The inner surface of adjustment member 
136 is shown as sequentially including: an inwardly-facing horizontal 
cylindrical surface 204 extending rightwardly from left end face 202, a 
rightwardly-facing annular vertical surface 205, and an 
internally-threaded portion 206 continuing rightwardly therefrom to join 
right end face 203. The outer surface of adjustment member 136 is shown as 
including an outwardly-facing horizontal cylindrical surface 208, a 
leftwardly-facing annular vertical surface 209, an outwardly-facing 
horizontal cylindrical surface 210, a leftwardly-facing annular vertical 
surface 211, an externally-threaded portion 212, an outwardly-facing 
horizontal cylindrical surface 213, and a rightwardmost polygonal portion 
214. Polygonal portion 214 is adapted to be grasped by a suitable turning 
tool, and rotated relative to the body inner part to selectively vary the 
position of surface 209 relative to the body inner part. Surfaces 210, 152 
are arranged in closely-spaced facing relation, and the joint therebetween 
is sealed by an O-ring 215. 
The plunger guide 138 is shown as being a horizontally-elongated solid 
member operatively arranged within the return spring adjustment member 
136. More particularly, plunger guide 138 has an annular vertical left end 
face 216; an annular vertical right end face 218; and an outer surface 
which sequentially includes (from left to right): an outwardly-facing 
horizontal cylindrical surface 219 extending rightwardly from left end 
face 216, a leftwardly-facing annular vertical surface 220, and an 
externally-threaded portion 221 continuing rightwardly therefrom to join 
right end face 218. Surfaces 219, 204 are arranged in closely-spaced 
facing relation, and the joint therebetween is sealed by an O-ring 222. A 
blind hole 223 is shown as extending axially rightwardly into plunger 
guide 138 from its left end face 216, to receive and accommodate the right 
marginal end portion of plunger member 131. A diametrical slot 224 extends 
leftwardly into the plunger guide from its right end face 218 to receive 
and accommodate insertion of a suitable turning tool, such as a 
screwdriver, by which the plunger guide may be selectively rotated 
relative to the adjustment member. 
As best shown in FIG. 5, the armature 126 is a specially-configured annular 
member opertively arranged within chamber 122 for horizontal sliding 
movement therealong. Specifically, the armature has annular vertical left 
and right end faces 225, 226, respectively; and an outer surface which 
sequentially includes (from left to right): an outwardly-facing horizontal 
cylindrical surface 228 extending rightwardly from left end face 225, a 
leftwardly- and outwardly-facing frusto-conical surface 229, and an 
outwardly-facing horizontal cylindrical surface 230 continuing rightwardly 
therefrom to join right end face 226. Again, the radial clearance between 
armature outer surface 228 and outer body inner surface 142 forms a 
non-working radial air gap of substantially constant reluctance. Also, 
armature right end surface 226 and inner body left end face 150 form a 
working air gap of variable reluctance. The inner surface of the armature 
sequentially includes (from left to right): a leftwardly- and 
inwardly-facing frusto-conical surface 232, a leftwardly-facing annular 
vertical surface 233, an inwardly-facing horizontal cylindrical surface 
234, a rightwardly-facing annular vertical surface 235, and an 
inwardly-facing horizontal cylindrical surface 236 continuing rightwardly 
therefrom to join right end face 226. A plurality of horizontal 
through-holes, severally indicated at 238, extend between armature 
surfaces 233, 235 to permit the pressures on both sides of the 
inwardly-extending intermediate armature flange to equalize. 
A spring retainer, generally indicated at 239, is shown as being 
operatively mounted on the armature. Specifically, retainer 239 has 
annular vertical left and right end faces 240, 241, respectively; and an 
inner surface which sequentially includes (from left to right): a 
leftwardly- and inwardly-facing frusto-conical surface 242, a 
leftwardly-facing annular vertical surface 243, a leftwardly- and 
inwardly-facing frusto-conical surface 244, and an inwardly-facing 
horizontal cylindrical surface 245 continuing rightwardly therefrom to 
join right end face 241. The outer surface of spring retainer 239 
sequentially includes (from left to right): an outwardly-facing horizontal 
cylindrical surface 246 extending rightwardly from left end face 240, a 
rightwardly-facing annular vertical surface 248, and an outwardly-facing 
horizontal cylindrical surface 249 continuing rightwardly therefrom to 
join right end face 241. Spring retainer 239 is shown as being operatively 
associated with the armature such that retainer surfaces 240, 246 are 
arranged to face armature surfaces 235, 236, respectively. 
The return spring 129 is shown as being a coil spring which is compressed 
between adjustment member surface 209 and spring retainer surface 248. 
Spring 129 is compressed, and continuously urges the spring retainer 239 
and armature 126 to move leftwardly relative to the body. 
Coil 128 is shown as being wound around an outwardly-facing annular bobbin 
250. The annular vertical left face of the bobbin is arranged to engage 
body outer part surface 145, with an O-ring 251 sealing the joint between 
the bobbin inner surface and body outer part surface 144. Another O-ring 
252 is arranged to seal the joint between the inner surface of the bobbin 
and body inner part outer surface 155. The annular vertical right end face 
of the bobbin is shown as engaging body inner part surface 156. As in the 
first embodiment, the annular recess formed between retaining ring 162, 
and the body inner part 134 is shown as being filled with a suitable 
potting compound 253. 
Referring now to FIG. 5, the plunger member 131 is shown as being 
operatively arranged within chamber 122 for horizontal movement toward and 
away from seat 125. Specifically, the plunger member is shown as being a 
horizontally-elongated rod-like member generated about axis x--x. Plunger 
member 131 has circular vertical left and right end faces 254, 255, and an 
outer surface which sequentially includes (from left to right): a 
leftwardly- and outwardly-facing frusto-conical surface 256 extending 
rightwardly from left end face 254, an outwardly-facing horizontal 
cylindrical surface 258, and a rightwardly- and outwardly-facing 
frusto-conical surface 259 continuing rightwardly therefrom to join right 
end face 255. The diameter of plunger surface 258 is substantially equal 
to the diameter of the contact between the ball 130 and seat 125, when 
such elements engage one another. A pair of axially-spaced flanges 260, 
261 are shown as extending radially outwardly from plunger member surface 
258. Left flange 260 has a rightwardly-facing annular vertical surface 
262, while right flange 261 is shown as having a leftwardly-facing annular 
vertical surface 263. 
The cushioning means 131 is shown as including a first spring 264 
operatively compressed between left flange surface 262 and armature 
surface 233, and a second spring 265 operatively compressed between right 
flange surface 263 and armature surface 235. Each of these springs is 
continuously compressed, and therefore biases the plunger member to move 
to a certain centered position relative to the armature. These cushioning 
springs are preferably selected such that their spring rates will produce 
a desired flow characteristic. 
The left marginal end portion of the plunger member is shown as sealingly 
and slidably penetrating seal member 194, with its left end face 254 
engaging ball valve element 130. The right marginal end portion of the 
plunger member is shown as being received in plunger guide hole 223. In 
this regard, the diameter of plunger member surface 258 is less than the 
diameter of hole 223, so that fluid will not become entrapped between the 
right end face of the plunger member and the bottom of hole 223, and the 
pressure therebetween will be permitted to equalize with the pressure in 
chamber 122. If desired, a suitable vent opening could alternatively be 
provided in the plunger guide. It should be noted that all surfaces of 
plunger 131 rightwardly of seal 194, are exposed to the pressure within 
chamber 122, which, in turn, is at the inlet pressure by virtue of 
communicating passageway 184. Hence, because the diameter of plunger 
surface 258 is substantially equal to the diameter of the contact between 
the seated ball and seat, the rightwardly-acting force of the inlet 
pressure on the left surface of the seated ball will be substantially 
balanced by the leftwardly-acting force of the same pressure in chamber 
122, acting on the various plunger surfaces to the right of seal 194. 
Hence, the ball and plunger are effectively "balanced" against variations 
in the inlet pressure. In this second embodiment, the term "valve member" 
refers collectively to ball 130 and plunger 131. 
This second embodiment is assembled as shown in FIG. 4. When coil 128 is 
de-energized, return spring 129 will urge the armature, plunger and ball 
to move leftwardly relative to the body. However, the spacing between the 
various parts is such that, when the armature moves leftwardly, the ball 
valve element 130 sealingly engages seat 125 before armature left end face 
225 abuts body surface 176. Thus, as in the first embodiment, the second 
embodiment contemplates that some desirable over-travel of the armature 
occur after the ball valve element has engaged seat 125. such relative 
motion between the ball/plunger member and the armature is accommodated by 
compression of cushioning spring 264 and expansion of spring 265. Thus, 
the mass of the armature is effectively separated and uncoupled from the 
mass of the plunger and ball member when the ball valve element engages 
seat 125. 
The second embodiment shown in FIGS. 4-6 is also pressure-balanced. When 
the ball valve 130 engages its seat, the inlet pressure in inlet 
passageway 123 will also exist within chamber 122. Thus, by dimensioning 
and configuring the right marginal end portion of the plunger member to 
have substantially the same area as the area of the seat, the plunger 
member and the ball valve may be balanced against the inlet pressure. 
Of course, the position of the valve seat 125 relative to the body may be 
adjusted by selectively rotating the seat member relative to the body. 
Similarly, the compressive displacement of return spring 129 may be 
adjusted by selectively rotating adjustment member 136 relative to the 
body. When the coil is energized, the coil flux will move the armature 
rightwardly relative to the body. When the coil is de-energized, return 
spring 129 will drive the armature, plunger and ball leftwardly, with the 
cushioning means 132 effectively separating the mass of the armature from 
the mass of the plungere and ball when ball valve element 130 sealingly 
engages seat 125. Such arrangement is believed to substantially increase 
the operating life of the structure, particularly during high repetition 
rates of current supplied to the coil. 
Modifications 
The invention contemplates that many changes and modifications may be made. 
As has been demonstrated, the valve element may be a poppet, or a ball, or 
may have some other shape or configuration. Similarly, the seat may be 
provided at the end of a tubular collar, may be a frusto-conical or 
spherically-segmented surface, or may have some other shape. Line contact 
between the valve element and seat is preferred, but this need not 
invariably obtain. The various parts and components may be configured to 
other shapes and dimensions, as desired. For example, the tubular collar 
may be fashioned on end of poppet to form a simple inversion of the valve 
elements. The salient feature of the invention is to selectively uncouple 
or separate the mass of the armature from the mass of the valve element 
when the latter engages the seat, so that, during high repetition rates, 
the armature will not exert a momentum force on the seat. 
Therefore, while two preferred embodiments of the improved solenoid valve 
have been shown and described, and several modifications thereof 
discussed, persons skilled in this art will readily appreciate that 
various additional changes and modifications may be made without departing 
from the spirit of the invention, as defined and differentiated by the 
following claims.