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Патент USA US3085828

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April 16, 1963
c. R. HANNA
3,085,818
FLUID POWER APPARATUS
Filed July 7, 1961
2 Sheets-Sheet 1
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INVENTOR
Chn’ron R. Hanna
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BY
ATTORNEY
April 16, 1963
c. R. HANNA
3,085,818
FLUID POWER APPARATUS
Filed July 7, 1961
2 She‘ets-Sheet 2
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276
rates Patent
1
3,085,818
FLUID POWER APPARATUS
Clinton R. Hanna, Fort Lauderdale, Fla., assignor to
Westinghouse Electric Corporation, East Pittsburgh,
Pa, a corporation of Pennsylvania
Filed July 7, 1961, Ser. No. 122,528
12 Claims. (Cl. 280-124)
This invention relates to ?uid power apparatus, and
?ice
3,035,818
Patented Apr. 16, 1953
2
FIG. 3 is a sectional view of an alternative frequency
variation ?lter which may be substituted for that shown
in the dashed line box in FIG. 1 and referenced at F; and
FIG. 4 illustrates an alternative location of a metering
restriction in the pressure supply line to the pilot circuit.
In FIG. 1 there is indicated by the general reference
numeral 10, an acceleration responsive sensing and con
trol unit for cotnrolling the ?ow of ?uid between a ?uid
pressure supply system 12 and a ?uid power actuator
more particularly to vehicle stabilizing apparatus employ 10 type shock absorber 14. By way of example, the system
is hydraulic, and the ?uid may be oil. The actuator 14
ing ?uid power (actuator type) shock absorbers.
includes ‘a hollow cylinder 16 having slidably disposed
While this invention is related to the general ?uid power
therein a piston 18 which divides the cylinder into ex
?eld, speci?c aspects of it are improvements relating to
pansible chambers 20‘ and 22. The lower end of the
components and systems disclosed in US. Patent No.
2,976,052, and in US. patent application Serial No. 15 cylinder ‘'16 is closed with a ?uid sealing slip bushing 24
having an internal annular surface providing a bearing
775,430, ?led November 21, 1958, now Patent No.
for a piston rod 28 connected to the piston 18. -In a prac
3,035,852, and Serial No. 30,796, ?led May 23, 1960, now
tical example, the relative diameters of the piston Y18 and
Patent No. 3,013,810, directed to vehicle stabilization.
connecting rod 28 were arranged to provide an approx
One phase of the invention is directed to an improved
imately two to one ratio between the areas of the piston’s
pilot-controlled power exhaust and supply valve system for
upper and lower pressure faces 43 and 45. The bearing
controlling ?uid ?ow in and out of an expansible cham
surface of the bushing 24 is provided with a packing
ber of a power actuator, which system lends itself to an
extremely compact arrangement. Another aspect of the
gland 30 and an annular, high pressure leakage trapping
groove 32 connected to a return line 34 leading to a reser
invention concerns a linearized bidirectional damping
scheme in the line leading to an expansible chamber of 25 voir 3-6 in the ?uid power supply system ‘12. The cylinder
16 is coupled to the sprung mass 38 of a vehicle, for ex
the power actuator.
ample, its frame. On the other hand, the outer end of
In accordance with one embodiment of the invention,
piston rod 28 is coupled through ‘a bearing 39 to a bracket
?uid into and out of an expansible chamber of a ?uid
40 attached to the unsprung mass of the vehicle, for ex
power shock absorber is controlled by uniquely arranged
ample, an axle 42. "It is to be understood that the vehicle
tandem supply and exhaust valves located in a common
includes a sprung mass such as frame and body coupled
bore, and controlled by an inertia responsive pilot circuit.
through springs to an unsprung mass such as axles and
Fluid ?ow in and out of the expansible chamber on the
wheels.
opposite side of the piston passes through a line including
In addition to the return line 34 and reservoir 36, the
parallel oppositely “poled” damping valves shunted by a
linearizing ?xed ori?ce.
It is, therefore, an object of the present invention to
provide new and improved ?uid power component and
system structure.
Another object is to provide a simple and compact pilot
pressure responsive supply and exhaust valve structure for
controlling a ?uid power actuator.
Another object is to provide a more compact accelera
tion responsive sensing and control unit for controlling
?uid power supply system 12 includes a ?uid pump 41,
whose intake is connected to the ?uid reservoir 36, and
whose output is connected to an accumulator 44 and to
pilot and main supply lines 46 and 48, respectively. An
unloader valve 50 connected across the pump sets the
pressure level of accumulator 44 by passing ?uid when the
desired pressure has been reached. Although the supply
source 12 is shown as supplying ?uid under pressure to
only one shock absorber, such a supply source may be
employed to supply a plurality of shock absorbers. Each
Another object is to provide an acceleration responsive 45 Wheel position of a multi-wheeled vehicle may be pro
sensing and control unit for controlling ?uid flow in and
vided with a shock absorber and associated sensing and
out of a ?uid power actuator, the unit including a spring
control unit of the type disclosed herein.
pressed damping valve in a ?uid circuit leading to an ex—
The unit 10 houses many components of the system,
pansible chamber of the actuator, and the major part of
including valves and an inertia element 60. The latter
the damping valve and the entire associated spring being 50 is a relatively heavy mass, and is supported for pivotal
located in low pressure sites whereby heavy pressure
movement around an axis lying to one side and below its
proof housing is not required for the spring and said ma
center of gravity by a ?exible mounting, such as the leaf
?uid ?ow in and out of a ?uid power actuator.
jor part of the valve.
springs 62 and 64, secured to a top section 66 of a con
trol block 68 which is an integral body formed by two
or more of the above desired enumerated features in a 55 main sections including section 66 and a bottom section
vehicle stabilization system.
'70. A ?uid-tight cover 72, secured to the block 68, forms
Further objects and advantages of the present inven
a chamber 74 and surrounds the inertia element 60 with
tion will be apparent from the following description, ref
out impeding its movement. Fluid from the chamber re
erence being had to the accompanying drawings, wherein
turns to the reservoir 36 through a return pipe 75. In
a preferred form of the present invention is clearly shown. 60 response to a vertical or a lateral acceleration of the
A further object of the invention is to provide any one
In the drawings:
sprung mass 38, the inertia element 60 will tend to rotate
FIGURE 1 is a semi-diagrammatic view of a preferred
either clockwise or counterclockwise around its pivot,
form of the invention as embodied in a ‘vehicle stabilizing
depending upon the direction of acceleration. For ex~
system. Predominant in this ?gure is a sectioned view
ample, in response to upward or to leftward accelerations
of ‘an acceleration responsive sensing and control unit for 65 as viewed in FIG. 1, the sensing mass 60 will rotate
controlling ?uid flow into and out of a ?uid power actu
clockwise. On the other hand, in response to either down
ator-type shock absorber. In order to show the details
ward or rightward acceleration as viewed in this ?gure,
of the sensing and control unit, the proportions between
the sensing mass 60 will rotate counterclockwise around
this unit and other parts of the system are exaggerated
its pivot.
in FIG. 1;
70
The inertia element 68 is biased in a neutral position
FIG. 2 is a perspective view of a portion of 1FIG. 1 to
by a spring 76 which urges a piston plunger 78 against
clarify details of that portion;
the bottom of the sensing mass 60. Plunger 78 slides
3,085,818
in ‘a bore 83 connected through a temperature controlled
restricted passage 82 to thevchamber 74, which chamber
is ?lled with ?uid in a manner later described. Tempera
ture control of the degree of restriction is effected by a
bimetallic element 84 over the passage 82. This arrange
ment provides constant damping for the sensing inertia
element 60 at any temperature.
Pilot supply line 46 is connected through a ?lter screen
90, a passage 91, a metering ori?ce 92, a passage 93, a
high frequency ?lter 94 and a passage 95, to a pilot con
trolled pressure line 96, which terminates in an ori?ce
98 Whose size is controlled by a pilot valve 100 having a
stem 102 that is in contact with and follows the move
ments of an arm 184 attached to and extending from
the inertia element 61}. The ?lter 94 is an oil-?lled cavity
in block 68 with su?lcient volume to provide the required
compliance for attenuating system frequency response
A,
cylindrical member 126 to form an exhaust valve 170,
which when open connects chamber 138 with the upper
chamber 20 of actuator 14 through the passage 166,
chamber 122 and passage 124.
The annular step between the two diameters of mem
ber 125 provides a piston face 172 which is subject to
accumulator pressure through chamber 136 to urge the
member 125 leftward (PEG. 1), tending to open the ex
haust valve 168. Member 125 is urged in the opposite
direction by the pilot controlled pressure in chamber
134 acting on the end piston surface 174 of member
125, thus tending to close the exhaust valve 170.
It may now be stated that the primary function of pis
ton plug 146 is to permit both exhaust and supply valves
to have large perimeters Without requiring the driving
piston of the exhaust valve to be larger in area.
The
larger valve perimeter not only increases the speed of
the valves but also permits the supply valve to have a
large bore within it for the passage of oil to the ex
haust valve 170 when that valve is open. When member
20
by a wall 168 in block section 66, which wall is provided
125 travels to the right (FIG. 1) from an open position
with an aperture that has extending therethrough a guide
of exhaust valve 170, contact is ?rst made between seat
plug 110 with an aperture 112, through which the stem
168 and closure 167 to close valve 170, and upon further
102 of valve 100 slidably extends. Fluid leakage from
movement to the right of member 125, member 126 is
the chamber 196, past the slide ?t of the valve stem 102
moved to the right to open the supply valve 163. When
into chamber 74, together with other leakages, ?lls cham
the system is quiescent, that is, when it is not respond
ber 74 with ?uid. These leakages ?ll the chamber 74
ing to accelerations as later described, the balance of
rather slowly, and it is desirable at the time of initial
forces on members 125 and 126 is such that both the
installation to pour ?uid into the chamber through a
exhaust and the supply valves 17!) and 163 are closed.
normally plugged aperture 113 in the cover 72. Since
As hereinbefore stated the pilot controlled pressure in
the ?ow through the ori?ce 98 is controlled by valve 100
line 96 is determined by the position of the inertia ele
above a desired operating range. Pilot valve 100 and
ori?ce 98 are enclosed in a chamber 106 formed in part
whose position is determined by that of the inertia element
61), the pressure variation in line 96 is a function of the
position of the inertia element.
ment 60.
In response to clockwise movement of the in‘
ertia element, the pilot valve 160 follows the upward
movement of arm 104, thus reducing the pilot controlled
The ‘shock absorber 14 is controlled by a supply and
pressure in line 96. There is always su?icient pressure
exhaust power valve arrangement 120 responsive to the 35 in line 96 to push the valve 100 upward to force its
pilot controlled pressure and located within block 68 and
stem 102 into contact with the arm 104, so that valve 1%
connected through a chamber 122 and a passage 124 to
the upper chamber 20 of the shock absorber. The ar
rangement 120 includes hollow cylindrical valve members
125 and 126 arranged in tandem for slidable axial move
ment within a cylindrical bore 128 having a stepped con
tour with sections 129, 130 and 132 of different diameters.
Axially spaced along and open to the’ bore 128 are a
number of ?uid pressure chambers 134, 136, 138 and
140.
Pressure chamber 134 is connected through a re
striction 141 to the pilot controlled pressure line 96.
Pressure chamber 136 is connected to the pilot supply
line 46. Chamber 138 is coupled to the return line 34,
and chamber 140 is connected to the main supply line
follows the movement of arm 104-.
Counterclockwise
movement of the inertia element 61) forces valve lllt)
downward, thereby restricting the ori?ce 98 and increas
1ng the pilot controlled pressure in line 96. From the
foregoing description, it should now be apparent that,
through the pilot controlled valve system 129, the upper
chamber 20 of the actuator 14 is connected to the ac
cumulator main supply line 48 in response to counter
45 clockwise movement of the inertia element 60‘, from the
qu1escent reference and to the exhaust line 34 in response
to clockwise movement of the inertia element 60 from
the reference position.
Chamber 22 of the actuator 14 is connected through
48. Pressure chamber 122 is at the right end of bore 128. 50 a line 180, and a pair of oppositely “poled” damper valves
Cylindrical valve member 125 has a reduced portion
182 and 184 to the main supply line 48. The damper
142 and an enlarged portion 144 to conform with the ad
valves are one-way valves, and each is biased to a closed
jacent sections 130 and 132 of the bore 128. A “station
pos1t1on by a spring under ‘static conditions. Damper valve
ary” piston plug 146 is disposed with a piston ?t within
182 includes a rod 186 slidably disposed in a bore 188
the cylindrical member 125, and is ?xed at the end of a 55 which extends from the exterior surface of block section
rod 148 attached to a base plug 150 resiliently but tightly
66 to a chamber 198‘ that is connected through a cham
?tted within the enlarged section 132 of bore 128 by means
ber 192 to the main supply line 48. Chamber 191} is
of an O-ring 152 ?tted in an annular groove 153 in the
demarked from a chamber 194 by a valve seat 196 which
perimeter of the plug 150. Plug 15% bears against a struc
cooperates with a valve closure 198 formed at the lower
ture plug 154 closing the left end of bore 128. The pur 60 end of rod 186. The valve closure 198 is urged toward
pose of plug 146 will be described later.
the seat 196 by the free end of a ?at spring 200 secured
At the right end of cylindrical member 126 there is
an annular valve closure 160 which cooperates with an
annular valve seat 162 to form a supply valve 163, which
to the top of block 66. Actual contact between the
spnng 209 and the top of rod 186 is through an adjustable
contact screw 202 extending through a threaded aper
when opened conects the supply chamber 14%) to cham 65 ture in the free end of spring 260.
ber 122 which in turn is connected to the upper chamber
For convenience,
chambers 190 and 194 may be referred to as the upper
and lower chambers of valve 182.
20 of cylinder 14. A bias spring 164 urges member 126
Valve 184 is similar to valve 182 and has correspond
in a direction toward closure of the supply valve. A
thin pin 165 provides a stop for the spring 164 and the
ing parts. The upper chamber 204 of valve 134 connects
valve member 126 without impeding ?uid ?ow between 70 with the lower chamber 194 of valve 182. Lower cham
chamber 122 and a passage 166 extending axially through
ber 192 of valve 184 is coupled to the main pressure line
48 while the lower chamber 194 of valve 132 is con
valve member 126.
he right end of cylindrical member 125 is provided
nected through line 18!) to the lower chamber 22, of actu
ator 14. The spring 200 and a major part of the valve
with an annular valve closure 167 which cooperates with
an annular valve seat 168 on the adjacent left end of 75 rod 186 of each damper valve are located in low pres~
3,085,818“
5
sure zones that do not require heavy pressure proof sur
rounding structure such as would be required if these
parts were located within a chamber of the valve as was
the case in the system disclosed in the aforesaid US‘.
patent application Serial No. 775,430.
Damper valve 184 responds to upward motion of the
piston 18, of the actuator, allowing ?uid to ?ow from
the main supply line 48 through line 180 into the lower
6
the shock absorber to the sprung mass 318 in an upward
direction (FIG. 1). This acceleration will in turn cause
the inertia element 60 to rotate clockwise about its pivotal
axis causing the pilot valve ori?ce 918 to be relieved, al~
lowing greater ?uid ‘?ow through the ori?ce and result
ing in a reduction in pressure in the pilot controlled pres
sure line 96. The reduction in pressure in line 96 causes
the member 125 to move to the left (FIG. 1) and disen
chamber 22 of the vactuator. Damper valve ‘182 is op
gage from member 126, thereby opening exhaust valve
positely “poled” with respect to damper valve 184, and 10 170, and resulting in ?uid being discharged from the
responds to downward motion of the piston 18 and con
sequent contraction of chamber 22, causing ?ow of fluid
through line 180 past the damper valve V182 and into the
upper chamber 20 of the shock absorber 14 through the
exhaust valve 170 and into return line 34.
The disen
gagement of members 125 and 126 results in a more
main supply line 48. A small ori?ce 206 shunts the
?rm seating of the supply valve ‘163.
damper valves 182 and 1184 to linearize the ?ow through 15
When the ?uid discharge from chamber 20 of the
the valves. Without the ori?ce, the rate of ?uid transfer
shock ‘absorber occurs, a rapid reduction in pressure
past the damper valves in slow in the beginning of a dif
within this chamber takes place, allowing the piston 18
ference of pressure and increases as the pressure rises.
to move rapidly upward in response to the uneven terrain.
The action of the ori?ce is to provide an opposite action
The pressure from the accumulator in chamber 22 causes
with a rapid increase of flow at the beginning and a 20 the force from the underside of the piston '18’ to exceed
smaller increase of ?ow as the pressure rises. The two
the force on the upper side with the result that upward
actions combined result in a more nearly straight line
response curve for the damper valves.
accelerations of the sprung mass are greatly impeded.
The rapid upward movement of piston 13- reduces the
pressure within the chamber 22 causing the damper valve
Variations in the accumulator pressure supplied by
the pump 42 inherently affect the balance of the inertia 25 184 to open and supply more ?uid to chamber 22. The
element 60. To compensate for this, a pressure com
reduction in pressure within chamber 22 also results in
pensating piston 210 engages the bottom of the inertia
a reduction of the force imposed on the pilot valve con
element 60. This piston is positioned Within an off-cen
trol ‘arm by the feedback piston 224. This action tends
ter bore 212 extending axially through a round plug 214
to reduce the ?ow through the pilot valve ori?ce 98‘ with
disposed with a snug rotatable ?t in a bore 216 that con 30 the result that damping of the resonances of the vehicle
nects through conduits 218 and 220 to the pilot supply
masses occurs.
line 46. A ?lter screen ‘222 is interposed in the line 218.
If the vehicle wheel strikes a depression in the road
With this arrangement, variations in the accumulator pres
surface, resulting in a separation of the sprung and un
sure Wil be re?ected in a reaction of the piston 210 to
sprung masses, there will be a pressure rise within cham
compensate for changes of ?uid force at the ori?ce 98 35 ber 22. The ‘increase in pressure within chamber 22 as
and at a later described piston 224 on the opposite side of
piston 18 attempts to move downward along with the
the pivot axis of the inertia element 60. Thus, the inertia
unsprung mass, causes the sprung mass to attempt a
element 60 assumes the same average position for varying
following action. The downward acceleration of the
accumulator pressures. The position of piston 210 with
sprung mass causes a counterclockwise movement of the
in the plane of the bottom surface of the inertia element 40 inertia element 60 about its pivot, resulting in a restric
60 may be adjusted by turning the plug 214, thereby
tion of the ori?ce 98 and a build-up of pressure within
providing eccentric movement of the piston 210v around
the pilot pressure line ‘96. This in turn results in an
the axis of plug 214. To assist in turning the plug 214,
opening of the supply valve 163 and a more ?rm seating
it is provided near its upper end with a “hexagonal”
of the exhaust valve 170‘. Opening of the supply valve
shaped portion 226 for receiving a corresponding wrench. 45 163 results in an increase in pressure within chamber 20,
A screwdown strap 22.8 is used to clamp the plug 214
aiding the piston 18 in its downward movement due to
after it has been adjusted. The upper end of plug 214
the separation of the sprung and unsprung masses. The
passes loosely through an aperture in the strap 228.
resultant increase in pressure within chamber 22 is then
In order to provide velocity control to the inertia ele
relieved through damper valves 182 into the main pres
ment 60, a negative feedback piston 224, slidably dis 50 sure line 48. This rise in pressure within chamber 22
posed in an axial eccentric bore 232 of a plug 234, en
also results in a feedback pressure increase on piston 224,
gages the underside of arm 104 to apply forces tending
tending to rotate the inertia element 60 clockwise, there—
to oppose rotation of the inertia element in response to
acceleration forces. vPlug 234 is located in a bore 236
of block section 66, which bore communicates through
a screen ?lter 238 and a line 246‘ to the line 180, which
by providing velocity stabilization of the initial action of
the inertia element 60'.
The most linear portion of the valve travel versus out
put pressure (pressure in line 96) characteristic of the
pilot valve controlled ori?ce 98 is between 50% and 100%
of full pressure output. Full pressure output is when the
communicates with chamber 22 of the actuator 14. Thus,
the response of the feedback piston 224 is proportional
to the relative velocity of the movement of piston 18
ori?ce 98 is completely closed by the pilot valve 100. In
re?ected in pressure changes in chamber 22 above or 60 order to operate this system on the more linear portion
below the accumulator pressure during ?uid ?ow through
of the pilot characteristic, the various forces are balanced
to provide a quiescent operating point at approximately
one of the damper vlaves 182 and 184. ‘Plug 234 is
similar to and adjustable in the same manner as plug
75% output of the pilot controlled ori?ce. For com
patibility with this operating range, the piston surfaces
214. It is also clamped with the same clamping strap
65 174 and 172 of the member 125 of the supply and exhaust
228.
valve system 120 bear an approximate 2 to 1 ratio.
Operation of the system of FIG. 1 is as follows. As
It, for example, the accumulator pressure is 1500 p.s.i.,
suming that the sensing and control unit 10‘ is mounted
and the pilot valve is biased for quiescent operation at
on the sprung mass 38 along with the ?uid supply sys
tem 12, with the cylinder head of the actuator 14 also se
1125 p.s.i. (middle of range between 50% and 100% out
cured to the sprung mass 38, and the piston rod 28 con 70 put) then the piston surface 174 is subject to an average
pressure of 1125 p.s.i., and piston surface 172 is subject
nected to the unsprung mass 42 through bearing 39, the
following operation will take place. If in passing over
to a ?uid pressure of 15004 p.s.i. (accumlator pressure).
In addition to the accumlator pressure on piston surface
a roadbed, the undercarriage or unsprung mass 42 of
the vehicle momentarily encounters a rise in the road
172, the member 125 has applied to it in the same direc
bed, a force will be delivered through the springs and 75 tion a “lift” pressure on the end area (right end) circum
3,085,818
7
8
accumulator pressure through chamber 256. The pres
scribed by the closure member 167 of approximately 750
p.s.i., the pressure of the upper chamber 29 of the shock
sure of spring 264 is adjusted by a screw member 266 to
bring the output pressure to a desired value despite varia
tions in the above area ratio due to manufacturing toler
ances. In the particular circumstance, the valve propor
is approximately 2 to 1. At quiescent, chamber 22 of
tions were made to produce slightly more than 50%
the actuator 14 is subject to the accumulator pressure
pressure in the output and the adjustable spring was
1500 p.s.i., and therefore the upper chamber 20 of the
brought into play to reduce this pressure to the desired
actuator 14 is under approximately 750 p.s.i. pressure,
value.
thus accounting for the “lift” pressure on the right end
Although the desired operating range of the system
of member 125. At quiescent, the supply and exhaust 10
is below 20 cycles per second, the system is subjected to
valve system 129 is balanced to a closed position. for
oscillations and pressure variations above the desired fre
both supply and exhaust valves. The spring 164 just
absorber 14. It will be recalled that the ratio of the
upper area 43 of piston 18 to that of its bottom area 45,
quency range. In a practical example, the ?lter 94 was
arranged to have a delay of approximately .02 second in
overcomes the opposing forces on member 126 to provide
a net closing force to the supply valve 165. Exhaust
combination with the metering ori?ce 92 and pilot valve
resistances to attenuate the response of the system above
its needed range of about O—20 cycles per second. With
a feed ori?ce of approximately .015 inch, an oil volume
of approximately 2 cubic inches will provide su?icient
compliance to provide such a delay. Cut off frequency
is reduced as delay is increased, and delay is increased by
reducing the ori?ce or by increasing the oil cavity volume.
It may be noted that the oil cavity ?lter 94 is arranged
valve 170 is provided with a net closing force resulting
from the force due to pilot controlled pressure on piston
surface 174 in one direction, and a slightly less force
in the opposing direction due to pilot supply line pres
sure on piston surface 172 plus the “lift” pressure on the
right end of member 125. The diameter of the right
end of member 125 is slightly greater than that of the
left end of member 126 to insure seating of the exhaust
valve, and to reduce the “li?t” area at the right end of
so that ?uid ?ows in at the bottom and ?ows out at the
member 125 by such an amount that full system pressure
may be obtained through the supply valve with less than 25 ‘top in order to scavenge the air out of it and avoid ex
cessive compliance because of the compressibility of the
full system pressure in the pilot controlled pressure line.
entrained air.
Due to wear or maladjustment, the pilot valve 100 may
Alternatively, the spring piston type of ?lter in FIG. 3
open excessively and permit the exhaust valve 170 to move
may be substituted for the oil volume compliance of FIG.
to its maximum opening which may result in liquid
1. The dashed box F of FIG. 3 is substituted for the
hammering. To prevent the pilot controlled pressure
dashed box F of FIG. 1. The ?lter in FIG. 3 includes a
from ever falling below a desired minimum, for example,
cylinder bore 270 in which is disposed a spring biased
approximately half system pressure, and thus cause excess
piston 272 having an axial passage 274 terminating in a
lifting of the exhaust valve, a minimum pressure valve
metering ori?ce 276. The piston divides the bore into
250 is inserted in the circuit between the pilot supply
‘two chamber 278 and 280. Chamber 278 is connected
line 46 and the pilot pressure line 96 in a position to by
to chamber 258 and to pilot pressure line 96, while cham
pass the metering ori?ce 92 when the minimum pressure
ber 280 is connected to the pilot supply line 46. The
valve is open. Valve 250 includes a stem 252 axially
right end of piston 272‘ is provided with a stop which
slidable in a bore 254 in block 63. Bore 254 opens into
limits the movement of the piston to the right to prevent
a chamber 256 connected to the pilot supply line 46 and
demarked from a pressure chamber 258 by an annular 40 a complete collapse of the chamber. A spring 282 biases
the piston to the right against the pilot supply pressure.
valve seat 260, which cooperates with a valve closure
In operation the piston “?oats” intermediate the ends of
262 at the right end of the stem 252 (FIG. 1). A spring
the bore, and provides in the oil volume and the spring
264 urges the closure 262 toward the seat 264]. When
'su?icient compliance to provide the necessary delay.
valve seat 260 and valve closure 262 are engaged, valve
Because of the passage 274 through the piston, the spring
250 is in a closed position blocking chamber 256 from
is on the pilot pressure side. This allows the spring to
chamber 258.
be small because only a low average energy must be
Chamber 258 is connected through passage 93, the
stored.
frequency ?lter 94, and the passage 95 to the pilot control
An alternative for ori?ce 92 is shown in FIG. 4. In
pressure line 96. The dimensions of the valve, the area
ratios on opposite sides of the valve closure 262, and the 50 ‘this ?gure, ori?ce 92 and passage 91 are eliminated, and
an ori?ce 290 located in the stem 252 of valve 250 com
municates between chambers 256 and 258. Ori?ce 290
spring force 264 are arranged so that at or under a
desired minimum pressure in chamber 258, the accumu
is effectively in parallel with valve 250 and provides the
equivalent function of ori?ce 92.
lator pressure from line 46, applied through chamber 256
to the left side of the valve head 262, will drive the closure
262 to an open position to allow more ?uid to flow into 55
the pilot pressure circuit, thereby raising the pressure of
the pilot controlled pressure line 96 above the predeter
mined minimum. Should the maximum pilot valve open
It is to be understood that the herein described arrange
ments are simply illustrative of the principles of the in~
vention, and that other embodiments and applications are
within the spirit and scope of the invention.
I claim as my invention:
ing, because of maladjustment or wear be greater than
1. In a ?uid power actuated stabilizing system for a
that for which the control pressure drops to approximate 60
vehicle having respective sprung and unsprung masses
ly half of the accumulator pressure, the minimum pres
sure valve 256 will pass sufficient additional oil to prevent
further falling of the control pressure and to restore the
pressure. Thus, the exhaust valve is prevented from lift
ing so far from its seat as to cause liquid hammering.
By way of example and in conformance with the pres
sures mentioned, the ratio between the area on the right
side of the valve closure 262 to the area on the opposite
or underside of the valve closure is approximately 2 to 1.
and a ?uid power actuator with an expansible chamber
coupled between said masses, a sensing and control sys
tem for controlling the ?ow of ?uid in and out of said
65 expansible chamber, said system comprising an inertia
sensing device, a pilot pressure circuit having a pilot valve
‘responsive to said inertia sensing device for determining
the pressure of said pilot circuit, a body having a cylin
drical bore with one end axially pointing in a direction
Liquid passing through the valve upon its opening emerges 70 A and the other end pointing in an opposite direction B,
said body having a second chamber, the B end of the
at approximately half pressure because this pressure can
bore opening into the second chamber, cylindrical valve
force the valve closed by bearing upon the full area of the
mushroom head of the valve stem 252, which area as
stated, bears a ratio of approximately 2 to l to the annular
members C and D arranged in tandem within said bore
for axial slidable movement therein, valve member D
area underneath the valve which is acted upon by the 75 being between member C and the second chamber. valve
3,085,818
10
member D having a passage extending axially there
through, valve member D having closure means, said
body having a ?uid pressure supply port which is open
to said second chamber when member D is axially moved
cuit within said body and having a pilot valve responsive
to said inertia sensing device for determining the pres—
sure of said pilot circuit, said body having a cylindrical
in ‘the direction B and which is blocked from that chamber
the other end pointing in an opposite direction B, said
body having a second chamber, the B end of the bore
opening into the second chamber, cylindrical valve mem
by said closure ‘means in ‘response to movement of mem
ber D in the A direction, said body having an exhaust
port open to said bore at the juncture of the adjacent ends
of members C and D, said adjacent ends respectively being
bore with one end axially pointing in a direction A and
bers 'C and D arranged in tandem within said bore for
axial slidable movement therein, valve member D being
between valve member C and the second chamber to
a seat and a closure forming an exhaust valve which in
each other, valve member D having a passage extending
response to axial relative movement apart of members
axially therethrough, valve member D having closure
C and D opens the exhaust port to said passage in mem
ber D, and in response to relative movement together of
means, said body having a ?uid pressure supply por
which is open to said second chamber when member
members C and D blocks the exhaust port from said
passage in member D, ?uid passage means connecting the 15 D is axially moved in the direction B and which is blocked
from that chamber by said closure means in response
second chamber with the expansible chamber of the
to movement of member D in the A direction, said body
actuator, means for biasing member C in the direction
having an exhaust port open to said bore at the juncture
A, means for biasing member D in the direction A, and
of the adjacent ends of members ‘C and D, said adjacent
means for subjecting member C to the ?uid pressure of
said pilot circuit to urge member C in the direction B, 20 ends respectively being a seat and a closure forming an
exhaust valve which in response to axial relative move
the latter means at ‘a particular pressure forcing member
ment apart of members C and D opens the exhaust port
C into engagement with member D to close the exhaust
to said passage in member D, and in response to relative
valve and at greater pressure causing member C to move
movement together of members C and D blocks the ex
member D in the direction B to open the supply port to
the second chamber.
v25 haust port from said passage in member D, ?uid passage
means connecting the second chamber with the expansible
2. In a ?uid power actuated stabilizing system for a
chamber of the actuator, means for urging member C in
vehicle having respective sprung and unsprung masses and
the direction A, the latter means including a piston sur
a ?uid power actuator with an expansible chamber cou
face on said adjacent end of member C exposed to the
pled between said masses, an integral sensing and control
unit for controlling the ?ow of ?uid in and out of said 30 ?uid in said passage in member D, means for biasing
member D in the direction A, and means for subjecting
expansible chamber, said unit comprising. a body, an
member C to the ?uid pressure of ‘said pilot circuit to
inertia sensing device carried by said body, a pilot pres
urge member ‘C in the direction B, the latter means at a
sure circuit within said body and having a pilot valve re
particular pressure forcing member C into engagement
sponsive to said inertia sensing device for determining
the pressure of said pilot crcuit, said body having a cy 35 with member D to close the exhaust valve and at greater
pressure causing member C to move member D in the
lindrical bore with one end axially pointing in a direction
direction B to open the supply port to the second chamber.
A and the other end pointing in an opposite direction B,
4. In a ?uid power apparatus having a ?uid power
said body having a second chamber, the B end of the
bore opening into the second chamber, cylindrical valve
members C and D arranged in tandem within said bore for
axial slidable movement therein, valve member D being
actuator with an expansible chamber, a sensing and con
trol system for controlling the ?ow of ?uid in and out
of ‘said expansible chamber, said system comprising a
condition sensing device, a pilot pressure circuit having
between valve member C and the second chamber, valve
a pilot valve responsive to said sensing device for deter
member D having a passage extending axially there
mining the pressure of said pilot circuit, a body having
through, valve member D having closure means, said
body having a ?uid pressure supply port which is open to 45 a cylindrical bore, one end of the bore being a second
chamber which communicates with said expansible cham
said second chamber when member D is axially moved in
ber, reciprocable cylindrical valve members C and D
the direction B and which is blocked from that chamber
disposed in tandem within said bore, member D being
by said closure means in response to movement of mem
disposed between member C and the second chamber,
ber D in the A direction, said body having an exhaust
member D having an axial passage therethrough, one end
port open to said bore at the juncture of the adjacent
of said passage being exposed to said second chamber,
ends of members C and D, said adjacent ends respective
said body having a ?uid inlet port, member D having
ly being a seat and a closure forming an exhaust valve
valve closure means which opens said inlet port to said
which in response to axial relative movement apart of
second chamber in response to movement of member D
members C and D opens the exhaust port to said passage
toward said second chamber, and which closes the inlet
in member D, and in response to relative movement to
port from the second chamber in response to movement
gether of members C and D blocks the exhaust port from
of member D in the opposite direction, means biasing
said passage in member D, ?uid passage means connecting
member D to the closed position of the inlet port, mem
the second chamber with the expansible chamber of the
ber C having an axial bore therethrough, a piston dis
actuator, means for biasing member C in the direction
posed within said bore of member C and substantially
A, means for biasing member D in the direction A, and
?xed relative to said body whereby member C is axially
means for subjecting member C to the ?uid pressure of
movable relative to said piston, said body having an ex
said pilot circuit to urge member C in the direction B, the
latter means at a particular pressure forcing member C
into engagement with member D to close the exhaust
valve and at greater pressure causing member C to move
member D in the direction B to open the supply port to
the second chamber.
3. In a ?uid power actuated stabilizing system for a
vehicle having respective sprung and unsprung masses
and a ?uid power actuator with an expansible chamber
coupled between said masses, and wherein said actuator
has an expansible chamber, a sensing and control unit
for controlling the flow of ?uid in and out of said ex
pansible chamber, said unit comprising a body, an inertia
haust port open to said bore. the adjacent ends of mem—
bers C and D being respectively a seat and a closure
forming an exhaust valve which in response to relative
movement apart of members C and D opens the exhaust
.port to said passage in member D and in response to
relative movement together of members C and D blocks
the exhaust port from the passage in member D, member
70 C having a ?rst piston surface facing in the direction of
member D, means for applying ?uid pressure against said
?rst piston surface to urge member ‘C in a direction away
from member D, an outwardly facing piston surface on
that end of member C opposite said adjacent end of
sensing device carried by said body, a pilot pressure cir 75 member C, and means for subjecting said outwardly fac
8,085,818
11
ing piston surface to ?uid pressure from said pilot con
trolled pressure circuit to urge member C in the direction
toward member D.
5. In a ?uid power actuated stabilizing system for a
vehicle having respective sprung and unsprung masses and
a ?uid power actuator with an expansible chamber, the
12
member D in the opposite direction, means biasing mem
ber D to the closed position of the inlet port, member
C having an axial bore therethrough, a piston disposed
within said bore of member C and substantially ?xed
relative to said body whereby member C is axially mov
able relative to said piston, said body having an exhaust
port open to said bore, the adjacent ends of members
C and D being respectively a seat and a closure forming
actuator being coupled between said masses, a sensing
and control system for controlling the ?ow of ?uid in
an exhaust valve which in response to relative move
and out of said expansible chamber, said system com
prising an inertia sensing device, a pilot pressure circuit 10 ment apart of members C and D opens the exhaust
port to said passage in member D and in response to
having a pilot valve responsive to said inertia sensing
relative movement together of members C and D blocks
device for determining the pressure of said pilot circuit,
the exhaust port from the passage in member D, member
a body having a cylindrical bore, one end of the bore
C having a circumferential step and different diameter
being a second chamber which communicates with said
expansible chamber, reciprocable cylindrcal valve mem 15 portions on opposite sides of said step, the smaller di—
ameter portion of member C being adjacent to member
bers C and D disposed in tandem within said bore, mem
D whereby said step forms a piston surface facing in the
ber D being disposed between member C and the second
direction of member D, means for applying ?uid pressure
chamber, member D having an axial passage there
against said step piston surface to urge member C in a
through, one end of said passage being exposed to said
direction away from member D, an outwardly facing
second chamber, said body having a ?uid inlet port, mem
piston surface on that end of member C opposite said ad
ber D having valve closure means which opens said inlet
jacent end of member C and means for subjecting said
port to said second chamber in response to movement
outwardly facing piston surface to fluid pressure from said
of member D toward said second chamber, and which
pilot controlled pressure circuit to urge member C in the
closes the inlet port from the second chamber in response
to movement of member D in the opposite direction, 25 direction toward member D.
7. In a ?uid power actuated stabilizing system for a
means biasing member D to the closed position of the
vehicle having respective sprung and unsprung masses
inlet port, member C having an axial bore therethrough,
and a ?uid power actuator with an expansible chamber,
a piston disposed Within said bore of member C and
the actuator being coupled between said masses, a sens
substantial ?xed relative to said body whereby member
C is axially movable relative to said piston, said body hav 30 ing and control system for controlling the ?ow of ?uid
in and out of said expansible chamber, said system com
ing an exhaust port open to said bore, the adjacent ends
prising an inertia sensing device, 'a pilot pressure circuit
of members C and D being respectively a seat and a
having a pilot valve responsive to said inertia sensing
closure forming an exhaust valve which in response to
device for determining the pressure of said pilot circuit,
relative movement apart of members C and D opens the
exhaust port to said passage in member D and in re 35 a body having a cylindrical bore, one end of the bore
being a second chamber which communicates with said
sponse to relative movement together of members C and
expansible chamber, reciprocable cylindrical valve mem
D blocks the exhaust port from the passage in member
bers C and D disposed in tandem within said bore, mem
D, member C having a ?rst piston surface facing in the
ber D being disposed between member C and the second
direction of member D, means for applying ?uid pres
chamber, member D having an axial passage therethrough,
sure against said ?rst piston surface to urge member C
one end of said passage being exposed to said second
in a direction away from member D, an outwardly facing
chamber, said body having a ?uid inlet port, member D
piston surface on that end of member C opposite to said
having valve closure means which opens said inlet port
adjacent end of member C, means for subjecting said
to said second chamber in response to movement of mem
outwardly facing piston surface to ?uid pressure from said
pilot controlled pressure circuit to urge member C in 45 ber D toward said second chamber, and which closes the
inlet port from the second chamber in response to move
the direction toward member D, said system having a
quiescent condition wherein said exhaust valve and said
ment of member D in the opposite direction, means bias
ing member D to the closed position of the inlet port,
valve closure are in their closed positions when said pilot
member C having an axial bore therethrough, a piston
pressure is at a predetermined level, said member C being
disposed within said bore of member C and substantially
responsive to pilot pressure variation in one direction
?xed relative to said body whereby member C is axially
from said predetermined level to move in the direction
movable relative to said piston, said body having an
of member D thereby to move member D to the open
position of said valve closure, member C being responsive
exhaust port open to said bore, the adjacent ends of
to pilot pressure variation in the opposite direction from
members C and D being respectively a seat and a closure
said predetermined level to move away from said mem 55 forming an exhaust valve which in response to relative
ber D to the open position of the exhaust valve.
movement apart of members C and D opens the exhaust
port to said passage in member D and in response to
6. In a ?uid power apparatus having a ?uid power
relative movement together of members C and D blocks
actuator with an expansible chamber, a sensing and con
trol system for controlling the ?ow of ?uid in and out
the exhaust port from the passage in member D, member
of said expansible chamber, said system comprising a 60 C having a circumferential step and different diameter
condition sensing device, a pilot pressure circuit having
a pilot valve responsive to said sensing devise for deter
mining the pressure of said pilot circuit, a body having
a cylindrical bore, one end of the bore being a second
chamber which communicates with said expansible cham
ber, reciprocable cylindrical valve members C and D dis
posed in tandem within said bore, member D being dis
posed between member ‘C and the second chamber, mem
ber D having an axial passage therethrough, one end of
said passage being exposed to said second chamber, said
body having a ?uid inlet port, member D having valve
closure means which opens said inlet port to said second
chamber in response to movement of member D toward
said second chamber, and which closes the inlet port
from the second chamber in response to movement of
portions on opposite sides of said step, the smaller di
ameter portion of member C being adjacent to member
D whereby said step forms a piston surface facing in
the direction of member D, means for applying ?uid pres
sure against said step piston surface to urge member C
in a direction away from member D‘, an outwardly fac
ing piston surface on that end of member C opposite
said adjacent end of member C, means for subjecting
said outwardly facing piston surface to ?uid pressure
from said pilot controlled pressure circuit to urge mem
ber C in the direction toward member D, said system
having a quiescent condition wherein said exhaust valve
and said valve closure are in their closed positions when
said pilot pressure is at a predetermined level, said mem
ber C being responsive to pilot pressure variations in one
3,085,818
direction from said predetermined level to move in the
direction of member D thereby to move member D to
14
having a cylindrical bore, one end of the bore being a
second chamber which communicates with said expansible
the open position of said valve closure, member C being
chamber, reciprocable cylindrical valve members C and
responsive to variation in pilot pressure variation in the
D disposed in tandem within said bore, member D being
opposite direction from said predetermined level to move 5 disposed between member C and the second chamber,
away from said member D to the open position of the
member D having an axial passage therethrough, one
exhaust valve.
end of said passage being exposed to said second charn—
8. In a ?uid power actuated stabilzing system for a
ber, said body having a ?uid inlet port, member D having
vehicle having respective sprung and unsprung masses
valve closure means which opens said inlet port to said
and a ?uid power actuator with an expansible chamber,
the actuator being coupled between said masses, a sens
second chamber in response to movement of member D
toward said second chamber, and which closes the inlet
ing and control system for controlling the ?ow of ?uid
port from the second chamber in response to movement
in and out of said expansible chamber, said system com
of member D in the opposite direction, means biasing
prising an inertia sensing device, a pilot pressure circuit
member D to the closed position of the inlet port, mem
having a pilot valve responsive to said inertia sensing 15 ber C having an axial bore therethrough, a piston dis—
device for determining the pressure of said pilot circuit,
posed within said bore of member C and substantially
a body having a cylindrical bore, one end of the bore
?xed relative to said 'body whereby member C is axially
being a second chamber which communicates with said
movable relative to said piston, said body having an ex
expansible chamber, reciprocable cylindrical valve mem
haust port open to said bore, the adjacent ends of mem
bers C and D disposed in tandem within said bore, mem
bers C and D being respectively a seat and a closure
ber D being disposed between member C and the second
forming an exhaust valve which in response to relative
chamber, member D having an axial passage therethrough,
movement apart of members C and -D opens the exhaust
one end of said passage being exposed to said second
port to said passage in member D and in response to
chamber, said body having a ?uid inlet port, member D
relative movement together of members C and D blocks
having valve closure means which opens said inlet port 25 the exhaust port from the passage in member D, mem
to said second chamber in response to movement of mem
ber C having a ?rst piston surface facing in the direction
ber D toward said second chamber, and which closes the
of member D, means for applying substantially constant
inlet port from the second chamber in response to move
?uid pressure against said ?rst piston surface to urge
ment of member D in the opposite direction, means bias
member C in a direction away from member D, an out
ing member D to the closed position of the inlet port, 30 wardly facing piston surface on that end of member C
member C having an axial bore therethrough, a piston
opposite said adjacent end of member C, means for sub
disposed within said bore of member C and substantially
?xed relative to said body whereby member C is axially
jecting said outwardly facing piston surface to ?uid pres
sure from said pilot controlled pressure circuit to urge
movable relative to said piston, said body having an ex
haust port open to said bore, the adjacent ends of mem 35 member C in the direction toward member D, said system
having a quiescent condition wherein said exhaust valve
bers C and B being respectively a seat and a closure
and said valve closure are in their closed positions when
forming an exhaust valve which in response to relative
said pilot pressure is at a predetermined level, said mem
movement apart of members C and D opens the exhaust
ber C being responsive to pilot pressure variation in one
port to said passage in member D and in response to
relative movement together of members C and D blocks 40 direction from said predetermined level to move in the
direction of member D thereby to move member D to the
the exhaust port ‘from the passage in member D, mem
open position of said valve closure, member C being
ber C having a circumferential step and different di
responsive to variation in pilot pressure variation in the
ameter portions on opposite sides of said step, the smaller
opposite direction from said predetermined level to move
diameter portion of member C being adjacent to member
D whereby said step forms a piston surface facing in 45 away from said member D to the open position of the
exhaust valve.
the direction of member D, means for applying ?uid pres
10. In a ?uid power actuated stabilizing system for a
sure against said step piston surface to urge member C
vehicle having respective sprung and unsprung masses and
in a direction away from member D, a piston surface
a ?uid power actuator with an expansible chamber, the
at said adjacent end of member C subject to the pressure
of the ?uid in said passage through member D for urging 50 actuator being coupled between said masses, an integral
sensing and control unit for controlling the ?ow of ?uid
member C in the direction away from member D, the
in and out of said expansible chamber, said unit com
opposite end of member C having a piston surface sub
prising a body, an inertia sensing device carried by said
ject to the pressure of said pilot pressure circuit for urg
body, a pilot pressure circuit within said body and having
ing member C toward member D, said system having a
quiescent condition wherein said exhaust valve and said 55 a pilot valve responsive to said inertia sensing device for
determining the pressure of said pilot circuit, said body
valve closure are in the closed position when said pilot
having a cylindrical bore, one end of the bore being a
pressure is at a predetermined level, said member C
second chamber which communicates with said expansible
being responsive to pilot pressure variation in one direc
chamber, reciprocable cylindrical valve members C and
tion from said predetermined level to move in the direc
tion of member D thereby to move member D‘ to the 60 D disposed in tandem within said bore, member D being
disposed between member C and the second chamber,
open position of said valve closure, member C being re
member D having an axial passage therethrough, one end
sponsive to variation in pilot pressure variation in the
of said passage being exposed to said second chamber,
opposite direction from said predetermined level to move
said body having a ?uid inlet port, member D having
away from said member D to the open position of the
exhaust valve.
65 valve closure means which opens said inlet port to said
second chamber in response to movement of member D
9. In a-?uid power actuated stabilizing system for a
toward said second chamber, and which closes the inlet
vehicle having respective sprung and unsprung masses and
port from the second chamber in response to movement
a ?uid power actuator with an expansible chamber, the
of member D in the opposite direction, means biasing
actuator being coupled between said masses, an integral
sensing and control unit for controlling the ?ow of ?uid 70 member D to the closed position of the inlet port, mem
ber C having an axial bore therethrough, a piston dis
in and out of said expansible chamber, said unit com
prising a body, an inertia sensing device carried by said
posed Within said bore of member C and substantially
body, a pilot pressure circuit within said body and having
?xed relative to said body whereby member C is axially
a pilot valve responsive to said inertia sensing device for
movable relative to said piston, said body having an ex~
determining the pressure of said pilot circuit, said body
haust port open to said bore, the adjacent ends of mem
3,085,818
15
bcrs C and D being respectively a seat and a closure
forming an exhaust valve which in response to relative
movement apart of members C and D opens the exhaust
port to said passage in member D and in response to
relative movement together of members C and D blocks
the exhaust port from the passage in member D, member
C having a circumferential step and different diameter
portions on opposite sides of said step, the smaller diam
eter portion of member C being adjacent to member D
whereby said step forms a piston surface facing in the
direction of member D, means for applying substantially
constant ?uid pressure against said step piston surface
to urge member C in a direction away from member D,
an outwardly facing piston surface on that end of mem
16
by said step forms a piston surface facing in the direction
of member D, means for applying substantially constant
?uid pressure against said step piston surface to urge
member C in a direction away from member D, a piston
surface at said adjacent end of member C subject to the
pressure of the ?uid in said passage through member D
for urging member C in the direction away from mem
ber D, the opposite end of member C having a piston
surface subject to the ?uid pressure of said pilot pressure
circuit for urging member C toward member D, said
system having a quiescent condition wherein said exhaust
valve and said valve closure are in the closed position
when said pilot pressure is at a predetermined level, said
member C being responsive to pilot pressure variation in
one direction from said predetermined level to move in
ber C opposite said adjacent end of member C, means 15 the
direction of member D thereby to move member D
for subjecting said outwardly facing piston surface to ?uid
to
the
open position of said valve closure, member C
pressure from said pilot controlled pressure circuit to urge
being responsive to variation in pilot pressure variation
member C in the direction toward member D, said system
in the opposite direction from said predetermined level
having a quiescent condition wherein said exhaust valve
to move away from said member D to the open position
20
and said valve closure are in their closed positions when
of the exhaust valve.
said pilot pressure is at a predetermined level, said mem
12. In a ?uid power apparatus having a ?uid power
ber C being responsive to pilot pressure variation in one
actuator with an expansible chamber, a sensing and con~
direction from said predetermined level to move in the
trol system for controlling the ?ow of ?uid in and out
direction of member D thereby to move member D to
of said expansible chamber, said system comprising a
the open position of said valve closure, member C being
condition sensing device, a pilot pressure circuit having a
responsive to variation in pilot pressure variation in the
pilot valve responsive to said sensing device for deter—
opposite direction from said predetermined level to move
mining the pressure of said pilot circuit, a body having
away from said member D to the open position of the
a cylindrical bore with one end axially pointing in a
exhaust valve.
direction A and ‘the other end pointing in an opposite
11. In a ?uid power actuated stabilizing system for 30 direction B, said body having a second chamber, the B
a vehicle having respective sprung and unsprung masses
end of the bore opening into the second chamber, cylin
and a ?uid power actuator with an expansible chamber,
drical valve members C ‘and D arranged in tandem with
the actuator being coupled between said masses, an in
in said bore for axial slidable movement therein, valve
tegral sensing and control unit for controlling the ?ow 35 member D being between member C and the second
of ?uid in and out of said expansible chamber, said unit
chamber, valve member D having a passage extending
comprising a body, an inertia sensing device carried by
axially therethrough, valve member D having closure
said body, a pilot pressure circuit within said body and
means, said body having a ?uid pressure supply port
having a pilot valve responsive to said inertia sensing
which is open to said second chamber when member D
device for determining the pressure of said pilot circuit, 40 is axially moved in the direction B and which is blocked
said body having a cylindrical bore, one end of the bore
from that chamber by said closure means in response to
being a second chamber which communicates with said
movement of member D in the A direction, said body
expansible chamber, reciprocable cylindrical valve mem
having an‘ exhaust port open to said bore at the juncture
bers C and D disposed in tandem within said bore, mem_
of the adjacent ends of members C and D, said adjacent
ber D being disposed between member C and the sec 45 ends respectively being a seat and a closure forming an
ond chamber, member D having an axial passage there
exhaust valve which in response to axial relative move
through, one end of said passage being exposed to said
ment ‘apart of members C and D opens the exhaust port
second chamber, said body having a ?uid inlet port, mem
to said passage in member D, and in response to relative
ber D having valve closure means which opens said inlet
movement together of members C and D blocks the ex
port to said second chamber in response to movement of
haust port from said passage in member D, ?uid passage
member D toward said second chamber, and which closes
means connecting the second chamber with the expansible
the inlet port from the second chamber in response to
chamber of the actuator, means for biasing member C in
movement of member D in the opposite direction, means
the direction A, means for biasing member D in the direc
biasing member D to the closed position of the inlet port,
tion A, and means for subjecting member C to the ?uid
member C having an axial bore therethrough, a piston 55 pressure of said pilot circuit to urge member C in the
disposed within said bore of member C and substantially
direction B, the latter means at a particular pressure forc
?xed relative to said body whereby member C is axially
ing member C into engagement with member D to close
movable relative to said piston, said body having an ex
the exhaust valve and at greater pressure causing member
haust port open to said bore, the adjacent ends of mem
C to move member D in the direction B to open the
bers C and D being respectively a seat and a closure
supply port to the second member.
forming an exhaust valve which in response to relative
movement apart of members C and D opens the exhaust
References Cited in the ?le of this patent
port to said passage in member D and in response to rela
UNITED STATES PATENTS
tive movement together of members C and D blocks the
Boulogne ____________ __ Jan. 11, 1944
exhaust port from the passage in member D, member C 65 2,338,895
2,501,305
Bennett _____________ __ Mar. 21, 1950
having a circumferential step and different diameter por
2,860,889
Hanna ______________ __ Nov. 18, ‘1958
tions on opposite sides of said step, the smaller diameter
portion of member C being adjacent to member D where
2,999,513
Oetiker _____,__,_ _____ __ Sept. 12, 1961
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