Adjustable stroke solenoid operated cartridge valve

A lower cost valve results from the use of a single machined part for a valve housing. The housing is made of a non-magnetic material which can be less expensive and eliminates the requirement for screens or filters in automotive applications. Providing a one-piece plunger and pilot valve with a high guiding length minimizes tilting of the pilot. Further, the one-piece housing allows for one common bore for guiding the plunger with the pilot and a poppet. The two ideal concentric surfaces make the poppet outer diameter concentric to the pilot hole. Finally, the use of an adjustable stroke valve eliminates the need for a separate needle valve, providing further cost savings.

FIELD OF THE INVENTION 
This invention relates to valves and, more particularly, to an adjustable 
stroke solenoid operated cartridge valve. 
BACKGROUND OF THE INVENTION 
In one form of a fluid flow control valve, a flow control element or valve 
member is movably positioned in a valve chamber between first and second 
valve positions for selectively fluidically coupling valve ports. The flow 
control element may be directly actuated by a solenoid operated plunger 
operatively associated with the flow control element. Alternatively, the 
flow control element may be actuated by a pilot valve which is directly 
actuated by a solenoid operated plunger. In either case, the solenoid 
controllably positions the plunger to move either the flow control element 
to an actuated position or the pilot valve to an actuated position to 
allow movement of the valve member. 
Typically, the valve chamber is provided by a two-piece valve housing of a 
magnetic material capable of withstanding high fluid pressure. The plunger 
is slidably received in a sleeve braised between the valve housing and a 
tube stop. To bias the plunger to a normal or an actuated position, the 
plunger typically includes a counterbore at either end receiving a spring 
biasing the plunger in a suitable direction. This type of assembly 
requires increased manufacturing cost. Also, misalignment can occur while 
braising the sleeve to the tube housing. 
One application for a cartridge valve of the two position type is in 
automobiles. Automobiles use single acting cylinders operated at 
relatively low pressure on the order of 500-600 psi, with 1000 psi being 
maximum. As a plurality of valves may be necessary in an automobile, 
economies in manufacturing are desirable to provide cost effective 
solutions to satisfy control requirements. 
In higher pressure applications, a poppet type cartridge valve is required. 
With such a valve the poppet has a pilot hole and an orifice. It is 
necessary to catch the pilot valve in the pilot hole. As such, it must be 
properly guided and therefore must be concentric in the poppet bore. Also, 
the pilot valve is conventionally connected to the plunger with a pin 
which allows for floating of the two parts relative to one another. This 
further makes it more difficult to provide the required centering of the 
pilot valve relative to the pilot hole. 
A specific automotive application for cartridge valves is in connection 
with so called "low rider" automobiles. The typical shock absorber is 
replaced with an hydraulic cylinder. A motor operated hydraulic power unit 
in the trunk applies pressure to the cylinder to raise the vehicle. The 
cartridge valve is used to lower the vehicle. The cartridge valve controls 
return flow from the cylinder to the tank. Lowering speed may be 
controlled with a needle valve to limit return flow rate. This requires an 
additional component and additional hydraulic connections. 
The present invention overcomes one or more of the problems discussed 
above. 
SUMMARY OF THE INVENTION 
According to the invention, a low cost cartridge valve is provided having 
adjustable stroke. 
It is one object of the invention to provide a cartridge valve including a 
one-piece valve housing. 
It is another object of the invention to provide a cartridge valve using a 
one-piece pilot valve and plunger guided in a common bore. 
Broadly, there is disclosed herein a solenoid operated cartridge valve 
comprising an elongate cylindrical valve housing having an axial 
throughbore defining an interior chamber, one end of the housing 
comprising a port end including a plurality of port openings, and an axial 
opposite end comprising a sleeve end receivable in a solenoid, in use. A 
valve member is movable in the chamber at the port end between first and 
second valve positions for selectively coupling the port openings, the 
valve member having an axial pilot throughbore defining a pilot chamber. A 
solenoid plunger is movable in the interior chamber at the sleeve end. A 
pilot valve is movable in the pilot chamber for selectively opening or 
closing the pilot throughbore. Means are provided for coupling the pilot 
valve to the plunger for axial movement therewith for selectively 
positioning the pilot valve, and thus also the valve member. A stop is 
mounted to the valve housing at the sleeve end for retaining the plunger 
in the chamber to provide full stroke movement of the pilot valve between 
first and second axial positions. Biasing means are operatively associated 
with the plunger for normally maintaining the pilot valve in one of the 
first and second axial positions. Adjustable means are operatively 
associated with the valve housing for adjustably limiting movement of the 
pilot valve between the first and second axial positions to control flow 
rate through the cartridge valve. 
It is a feature of the invention that the coupling means comprises the 
plunger being integral with the pilot valve. 
It is another feature of the invention that the pilot through opening 
comprises a relatively large diameter counterbore opening into the chamber 
coupled to a relatively small diameter coaxial pilot hole adjacent the 
housing port end. 
It is a further feature of the invention that the pilot valve is loosely 
received in the counterbore and the pilot valve has a needle end received 
in the pilot hole for selectively opening or closing the pilot hole. 
It is still another feature of the invention that the plunger is an 
elongate plunger having an outer diameter slightly less than an inner 
diameter of the housing throughbore to maintain the plunger centered in 
the valve housing so that the pilot valve needle end is concentric with 
the pilot hole. 
It is yet another feature of the invention that the valve housing is of a 
non-magnetic material. 
It is still an additional feature of the invention that the biasing means 
comprises a spring received in the chamber and acting between the stop and 
the plunger for normally maintaining the valve member in one of the first 
and second valve positions. 
It is still an additional feature of the invention that the adjustable 
means comprises an elongate rod extending through said valve housing for 
selectively engaging the pilot valve to limit movement between the first 
and second axial positions. 
It is still yet a further feature of the invention that the adjustable 
means further comprises a screw operatively associated with the rod, the 
screw being threadably received in the housing for adjusting axial 
position of the rod in the valve housing. 
It is still another feature of the invention to provide a lock nut threaded 
to the screw for maintaining the rod in a desired axial position. 
In accordance with another aspect of the invention there is disclosed 
herein an elongate cylindrical valve housing having an axial counterbore 
at a sleeve end defining an interior chamber, an axial opposite port end 
of the housing having an axial throughbore opening to the interior chamber 
to provide an end port opening and defining a valve seat, and a radially 
extending through opening in the housing opening in the said interior 
chamber and defining a side port opening, the sleeve end being receivable 
in a solenoid, in use. A valve member is movable in the chamber between a 
first valve position seated on the valve seat for selectively preventing 
coupling between the end and side port openings, and a second valve 
position spaced from the valve seat for coupling the end and side port 
openings, the valve member having an axial pilot throughbore defining a 
pilot chamber. A solenoid plunger is movable in the interior chamber at 
the sleeve end. A pilot valve is movable in the pilot chamber for 
selectively opening or closing the pilot throughbore. Means are provided 
for coupling the pilot valve to the plunger for axial movement therewith 
for selectively positioning the pilot valve, and thus also the valve 
member. A stop is mounted to the valve housing at the sleeve end for 
retaining the plunger in the chamber to provide full stroke movement of 
the pilot valve between first and second axial positions. Biasing means 
are operatively associated with the plunger for normally maintaining the 
valve member in one of the first and second valve positions. Adjustable 
means are operatively associated with the valve housing for adjustably 
limiting movement of the pilot valve between the first and second axial 
positions to control flow rate through the cartridge valve. 
In accordance with the invention, a lower cost valve results from the use 
of a single machined part for the valve housing. Moreover, the housing is 
made of a non-magnetic material which can be less expensive and eliminates 
the requirement for screens or filters in automotive applications. 
Similarly, threadably connecting the tube stop to the valve housing sleeve 
end eliminates the requirement of braising in manufacturing. Providing a 
one-piece plunger and pilot valve with a high guiding length minimizes 
tilting of the pilot. Further, the one-piece housing allows for one common 
bore for guiding the plunger with the pilot and the poppet. The two ideal 
concentric surfaces make the poppet outer diameter concentric to the pilot 
hole. Finally, the use of an adjustable stroke valve eliminates the need 
for a separate needle valve, providing further cost savings, and 
eliminating additional hydraulic connections. 
Further features and advantages of the invention will readily be apparent 
from the specification and from the drawings.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 illustrates a solenoid operated cartridge valve 10 according to the 
invention. 
The valve 10 includes a stationary valve housing 12 having a threaded outer 
portion 14 adapted to be threaded into a fluid port (not shown). 
With reference also to FIG. 2, the valve housing 12 is of elongate, 
one-piece cylindrical construction having an axial counterbore 16 at a 
sleeve end 18 defining an interior chamber 20. An axially opposite housing 
port end 22 has an axial throughbore 24 opening to the interior chamber 20 
to provide an end port opening 26. A plurality of radially extending 
through openings 28 in the housing 12 open into the interior chamber 20 
and define side ports 30. The end port 26 is selectively opened or closed 
by a valve member, or poppet 32 seating on an annular valve seat 34 where 
the throughbore 24 opens into the interior chamber 20. The valve seat 34 
is sealed in the bore 16 with an O-ring 35. 
First and second sealing rings 36 and 38 are provided on the valve housing 
12 for sealing the valve assembly within the fluid port. A backup ring 40 
is associated with the sealing ring 38 in a suitably outwardly opening, 
annular recess 42 of the valve housing 12. 
As used herein, the relative term "outer" or "outward" refers to a 
direction axially toward the port end 22, and the relative term "inner" or 
"inward" refers to a direction axially away from the port end 22, i.e. 
axially toward the sleeve end 18. 
When the valve 10 is installed in a suitable fluid port, fluid pressure 
between the seals 36 and 38 is applied through the side ports 30 against 
the poppet 32. In the illustrated embodiment, the poppet 32 has an outer 
seating portion 43 engaging the valve seat 34. The poppet 32 is movable in 
the interior chamber 20 between a first valve position as shown seated on 
the valve seat 34 for selectively preventing coupling between the end port 
26 and the side port 30, and a second valve position, not shown, spaced 
from the valve seat 34 for fluidically coupling the end port 26 with the 
side ports 30. 
The poppet 32 has an outer diameter slightly less than an inner diameter of 
the chamber 20 so that it is slidable therein with minimal tilting. The 
poppet 32 has an enlarged counterbore 44 opening inwardly and a smaller 
diameter coaxial pilot hole 46 concentrically positioned in the interior 
chamber 20. An orifice 47 is provided through the sidewall of the poppet 
32. 
The pilot hole 46 is normally closed by a pilot valve 48 releasably 
received in the poppet counterbore 44 and having a needle end 50 for 
selectively opening or closing the pilot hole 46. 
The pilot valve 48 is integrally formed with a solenoid plunger 52 axially 
movable in the interior chamber 20 at the sleeve end 18. Particularly, the 
plunger 52 is coaxial with the pilot valve 48 and is positioned inwardly 
relative thereto. The plunger 18 is elongate in construction and has an 
outer diameter slightly less than an inner diameter of the interior 
chamber 20 to maintain the plunger 52 centered in the chamber 20. The 
pilot valve 48, being integral with the plunger 52, is guided in the same 
bore, i.e., the interior chamber 20, as is the plunger. As a result, the 
pilot valve needle end 50 is concentric with the pilot hole 46, 
eliminating the requirement for a guiding hole for the pilot valve needle 
end 50. The high guiding length of the plunger minimizes tilting of the 
pilot valve 48, as is apparent. 
The use of a common bore 16 for both the pilot valve 48 and the plunger 52 
simplifies construction while avoiding misalignment problems. 
In the normally closed arrangement of the valve 10, the plunger 52 is 
biased outwardly by a helical coil spring 54 acting between a shoulder 55 
of a plunger inner end counterbore 56 and a plug or stop 60. The spring 54 
has sufficient strength to urge both the pilot valve 48 and the poppet 32 
outwardly into the seated arrangement of FIG. 2. The position of the stop 
60 defines full stroke movement of the plunger 52 and the pilot valve 48 
between a first or closed position, shown in FIG. 2, and a second or full 
open position (not shown) when the plunger 52 engages the stop 60. The 
amount of full or maximum stroke movement is represented by a gap G 
between the stop 60 and the plunger 52 under bias of the spring 54. 
The poppet orifice 47 provides a bleed passage for fluid communication 
between the side port 30 and a pilot chamber 62 defined by the poppet 
counterbore 44. Thus, in the normally closed position wherein the pilot 
valve 48 is closing the pilot opening 46, fluid pressure at the side port 
30 is transmitted through the poppet orifice 47 into the pilot valve 
chamber 62 and acts to maintain the poppet valve 32 in the closed position 
illustrated in FIG. 2, in cooperation with the spring 54. 
The pilot valve 48 is reciprocally moved from the seated position 
illustrated by suitable reciprocal, longitudinal movement of the plunger 
52 inwardly toward the stop 60 under the control of a solenoid coil 64 of 
conventional construction. The stop 60 is secured as by a threaded 
connection at 66 to the housing sleeve end 18 and using a suitable locking 
compound and sealed with an O-ring 67. Alternatively, the plug 60 could be 
connected to a sleeve end 18 using a swaged connection. 
A plug inner end 68 is threaded. A nut 70 is threaded to the threaded end 
68 to clamp the solenoid coil 64 between the nut 70 and a flange 72 
integral with the valve housing 12 at the sleeve end 18. 
In accordance with the invention the valve 10 is provided with an 
adjustable stroke. The stop 60 has a through bore 80 coaxial with a 
threaded inner end counter bore 82. The through bore 80 is coaxial with 
the plunger counterbore 56. The plunger 52 includes a coaxial through bore 
84 closed by the integral pilot valve 48. 
An elongate rod 86, having an enlarged outer head 88, extends through the 
stop bore 80 and the plunger bore 84. A screw 90 is threaded into the stop 
counter bore 82 as at 92. The rod 86 is captured between the pilot valve 
48 and the screw 90. A locking nut 94 on the screw 90 maintains a desired 
screw position. The screw 90 has a knurled head 96. By adjusting the screw 
90, by turning the screw head 96, a variable gap V is provided between the 
head 88 and the pilot valve 48 to limit axial movement and thus stroke of 
the pilot valve 48. In accordance with the invention the rod 86 can be 
integrally formed with the screw 90. 
Energization of the coil 64 as by applying electrical power across 
conductors 74, see FIG. 1, creates a magnetic field in space occupied by 
the plunger 52 to cause the same to move inwardly against the force of the 
spring 54 until it abuts the plug 60. Inward movement of the plunger 52 
which is integrally associated with the pilot valve 48 causes inward 
movement of the pilot valve 48 so as to unseat the needle end 50 from the 
poppet pilot hole 46. Thereafter, pressure at the side port 30 is greater 
than pressure at the pilot hole 46 and a lifting force moves the poppet 32 
forward inwardly to provide fluid flow between the side ports 30 and the 
end port 26. Movement can be further restricted, to adjust stroke, by 
turning the screw 90 so that the variable gap V is less than the full 
stroke gap G. With stroke adjusted the plunger 52 and pilot valve 48 move 
only until the pilot valve 48 abuts the head 88. Adjusting the stroke is 
used to control flow rate through the valve 10. 
Advantageously, the valve housing 12 is of a non-magnetic material such as, 
for example, aluminum, brass, bronze or stainless steel. The use of such a 
non-magnetic material is believed less expensive than a magnetic material 
and eliminates the requirement for filters or screens in fluid ports, in 
use. 
The valve 10 according to the invention is illustrated in a typical 
application schematically in FIG. 3. In this application, for automotive 
use, the valve 10 is used with a cylinder 100 to replace conventional 
shock absorbers for "low rider" shocks. 
With the solenoid 64 deenergized and a motor 102 on driving a pump 103 
fluid is pumped via a check valve 104 to the cylinder 100. This raises a 
load 106. To lower the load 106 the motor 102 is turned off. The solenoid 
64 is energized. This opens the valve 10 and fluid returns from the 
cylinder 100 to a tank 105. This lowers the load 106. The stroke of the 
valve 10 is adjustably selected, as described above, to control the return 
flow rate. By using the adjustable stroke valve 10 there is no need for a 
separate needle valve to control return flow rate. 
Thus, in accordance with the invention, there is disclosed a low cost 
adjustable stroke solenoid operated cartridge valve suitable for use in 
high pressure applications. Economies of manufacturing are provided by the 
use of a one-piece valve housing which can be made as a screw machined 
part. A common bore is provided for the poppet, plunger and pilot valve. 
Further economies are obtained by using a pilot valve integrally formed 
with a plunger which results in use of less parts and more reliable 
control. The guiding length of the plunger is sufficient to minimize 
tilting of the pilot valve to maintain concentricity for guiding the pilot 
valve relative to the poppet pilot hole. This in connection with the one 
piece housing allows one common bore for guiding the plunger with the 
pilot and also the poppet. The adjustable stroke eliminates the need for a 
separate needle valve.