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Патент USA US3028821

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APri] 10, 1962
R. D. RUMSEY ETAL
3,028,814
HIGH SPEED VARIABLE DISPLACEMENT PUMP
Filed Oct. 17, 1957
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Eo/?zz Doug/a5 Ramsey
April '10, 1962
,R. D. RUMSEY- ETAL
3,028,814
HIGH SPEED VARIABLE DISPLACEMENT PUMP
Filed 001;. 17, 1957
3 Sheets-Sheet 2
Fo/[l? Doug/a5 Ramsey
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Emma/f 6’. Mal/112L119
April 10, 1962
R. D. RUMSEY ETAL
3,028,814
HIGH SPEED VARIABLE DISPLACEMENT PUMP
Filed Oct. 17, 1957
3 Sheets-Sheet 3
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Pol/112 Doug/as Ramsey
Emmett 6’. Manning
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3,028,814
Patented Apr. 10, 1962
1
2
3,028,814
ment thereof in the speci?cation, claims and drawings, in
which:
Rollin Douglas Rumsey, Buffalo, and Emmett C. Man
FIGURE 1 is a vertical sectional 'view taken through
a pump embodying the principles of the invention;
HIGH SPEED VARIABLE DISPLACEMENT PUMP
ning, Lockport, N.Y., assignors to Houdaille Industries,
Inc, Butialo, N.Y., a corporation of Michigan
Filed Oct. 17, 1957, Ser. No. 699,807
4 Claims. (Cl. 1(23-161)
FIGURE 2 is a sectional view of reduced size taken
along line 11-11 of FIGURE 1, and illustrating the rela
tive positions of a pump cylinder and a fluid ?ow pas
sageway leading therefrom;
The present invention relates to improvements in con
' FIGURE 2ais a sectional view taken along line Ila-i
stant pressure variable displacement pumps, and more 10 Ila of FIGURE 1 and showing an end view of the valve
particularly to pumps of this character which are auto
plate;
~
matically adjustable in response to operating conditions
FIGURE 3 is‘a sectional view taken along line III—III
and requirements encountered during performance of
the pump.
of FIGURE 1;
FIGURE 4 is a sectional View taken along line IV—IV
More particularly, the invention relates to improve 15 of FIGURE 1; and,
ments in rotary pumps having a rotor carrying a pump
FIGURE 5 is a sectional view taken along line V-~V
ing means such as the type carrying radial pistons which
of FIGURE 4.
are actuated by engagement with the inner surface of a
As illustrated in FIGURES 1, 3 and 4, the pump is
substantially circular enclosing pump chamber eccen
enclosed by a housing ‘8 which may be provided with an
trically located with respect to the rotor. The displace 20 outwardly extending ?ange 10 for purposes of mounting
ment of the pump is varied by varying the eccentricity of
the pump housing, such as by bolts inserted through holes
the chamber with respect to the rotor. The invention
12, 14 and 16 in the housing. The housing is preferably
contemplates improvements in the control of the posi
formed of a casting which is suitably cored and tapped
tional displacement of the axis of the pump chamber be
for attachment of the various elements to be described.
tween substantially zero displacement and full displace 25 ‘At one end of the housing is a circular opening 18
ment to achieve a variation in pump output for constant
through which a pump driving shaft, not shown, will be
pressure delivery. The invention also contemplates im
extended ‘for driving a pump rotor 20. A shaft seal 21
provements which obviate the di?‘iculties which occur with
will surround the shaft and the seal is pushed against the
change in dimensions with temperature variation. The
rotor 29 by Belleville springs 19 held in place by an an
problem of the generation of heat in pumps of the variable 30 nular ring 23 which is held against the housing 3 by screws
delivery type when the delivery is reduced to zero is also
25. For enclosing the rotor and other parts within a
accommodated to correct problems heretofore encoun
housing chamber 22 de?ned by the housing, a housing cap
tered.
24 is attached to the end of the housing opposite the open
ing 18. The housing cap is suitably clamped to the end of
An object of the invention is, therefore, to provide an
improved variable displacement constant pressure rotary 35 the housing and secured thereto such as by bolts 26. A
pump.
gasket 28 is provided to prevent leakage of ?uid from
Another object of the invention is to provide a constant -
pressure variable displacement pump which is capable of
obtaining greater stability during operation, and-freedom
from vibration or chatter, and other dif?culties encoun
tered with variation in part dimensions with temperature
increase, and especially such as encountered due to the
diiterence in expansion between the pump housing and
the enclosed pump parts.
Another object of the invention is to provide a pump
of the type above described wherein improved position
ing and control means are provided for eccentrically lo
cating the chamber surrounding the pump rotor ‘for con“
trolling the output displacement of the pump.
Another object of the invention is to avoid the prob
within the housing. A shaft’gasket 30 is also provided
which will surround the pump driving shaft in a ?uid-tight
manner. This will permit the ?ow of cooling ?uid through
the housing in the manner which will later be described.
The pump rotor 20 is. mounted Within the housing
chamber 22 for rotation therein, and is substantially cylin
drical in shape. The rotor 20 has a shaft receiving socket
32 to which the shaft is connected for ‘driving the rotor
in rotation. Rotation will be maintained at a constant
speed, and the variable displacement constant pressure
output will be obtained in the manner to be described.
A plurality of circumferentially spaced radially ex
tending cylindrical holes are bored into the rotor as shown
50. at 3-4. Fitted into each of the cylindrical bores are
lems of overheating in a variable displacement pump when
pistons 36 which are mounted for reciprocation in a gen
the displacement reaches zero and the ?uid passing there
erally radial direction to move into and out of the cy
through reaches a minimum by providing a by-pass sup
lindrical openings or cylinders 34 to cause a pumping
ply of ?uid for cooling the pump.
action. The cylindrical bores are formed to angle for
A further object of the invention is to provide an im 55 wardly. As may be observed in FIGURE 3, the pistons
proved pump of the type wherein a rotor carries radially
are thus canted forward in such a way as to produce as
reciprocating pistons operated within an eccentric pump
low an overhanging couple as possible.
7
chamber, and wherein the pump chamber can easily and
‘Intake ?uid for the cylinders 34 is received through
accurately be positioned with respect to the rotor.
a ?uid passageway 38 in the rotor, as illustrated ‘in
Still another object of the invention is to provide a 60 FIGURES 1 and 2 with a separate passageway provided
pressure balanced valve plate for supplying ?uids to a
for each cylinder bore 34. Passageway 38 (FIGURES
rotary pump wherein the surface pressure between the
1 and 2), is a circular passageway canted in the direc
valve plate and pump will remain substantially constant
regardless of changes in ?uid supply pressure.
tion of rotation of the rotor 20 so that as the rotor turns
the fluid is rammed into the cylinder chamber, thereby
Another object of the invention is to provide for in 65 reducing the inlet pressure required to prevent cavita
creased ?uid supply pressure to a rotary pump to decrease
tion. The canted passageway 38, as it breaks through
cavitation effects without having to supply a separate
the face 39 of the rotor, forms an elliptical opening.
means for providing pressurized ?uid.
This feature is particularly desirable on high speed pumps
Other objects and advantages will become more ap 70 because it has been found necessary to run inlet pres
parent with the teaching of the principles of the invention
sure as high as 150 psi. in order to ‘force ?uid into the
in connection with the disclosure of the preferred embodi
pumping chambers with axial passageways. The fact
3,028,814
3
that the canted channel is in the wrong direction for dis
charge ?ow is relatively immaterial because at that time
no cavitation danger exists.
The pistons are forced inwardly in their reciprocating
movement by a ?rst inner modulating ring 40 which
surrounds the rotor and is eccentric thereto in normal
operating position. The modulator ring 40 may be
4
livery stroke of the piston, the ?uid passageway 38 com
municates with an arcuate slot 90 which extends around
the other half portion of the valve plate 72. This slot
90 leads to a delivery passageway 94 within a projection
96 integral with the valve plate. The arcuate slot 90
has substantially the same area as the outside diameter
of the valve plate projection 96, such that change in dis
charge pressure will have a minimum effect upon the
valve plate rubbing pressure.
The valve plate projection 96 extends into an opening
For operating the pistons, 10
shifted in a lateral direction to vary its eccentricity with
respect to the rotor to thereby vary the displacement or
effective output of the pump.
rollers 42 are positioned between each of the pistons
98 in the housing cap, and the projection 96 and the
connector sleeve 73 prevent the valve plate 72 from ro
and the modulating ring 40 with the rollers 42 positioned
tating with the rotor 20. The projection 96 contains a
with their axis extending parallel to the axis of the rotor
coil compression spring 100, which bears against a spring
20 and engaging the outer ends 44 of the pistons and the
inner surface 46 of the modulating ring 40. The rollers 15 supporting washer 102 within the opening 98 in the
housing cap and urges the valve plate 72 to a non-leaking
42 remain substantially stationary during operation of
the pump, inasmuch as the modulating ring is mounted
for rotation, the rotary driving force is applied to the
engagement with the face 74 of the rotor.
Fluid under
pressure is delivered from the pump through the delivery
or outlet passageway 104 in the housing cap. An 0
piston and the ring is carried therewith by at least one
of the rollers 42 frictionally engaging the modulating 20 ring 106 seals the projection 96 within the opening 98
of the cap.
ring 40 and carrying it in rotation with the rotor.
In the position illustrated in FIGURE 3, the modulat
‘For carrying the rollers 42 in place and rotating them
ing ring 40 is shifted to the left to reduce the pump dis
with the rotor 20, the rollers ‘42 are carried at one end
placement and shifted to the right to increase the displace
by an annular ?ange 48 at the end of the rotor 20.
The annular ?ange is provided with radial slots 50 at the 25 ment. For movement of the modulating ring to vary the
pump output, lateral forces are ‘applied to the outer ring
locations of the rollers and in assembly, the rollers are
66. To guide the outer ring in its lateral movement with
dropped in the slots ‘50 to be held between the pistons
in the housing chamber 22, opposed guide ascmblies 108
36 and the inner surface 46 of the modulating ring. The
and 110 are provided. The guide assemblies include a ring
other ends of the rollers are carried in slots 52 in an an
nular ring 54 which is mounted on the rotor to rotate 30 supporting bearing member 112 for the guide assembly
therewith.
The rotor is supported for rotation within the housing
8 on a ball bearing assembly 56 having bearing balls
108, and 114 for the guide assembly 110. An important
feature of the invention is the provision of thermally ex
pansible backing elements 116 and 118 for the guide bear
ings 112 and 114. The parts may be made of different
The ball bearing is supported in an annular socket 64 35 materials having dilferent rates of expansion. For ex
ample, the housing 3 may be of a material having a great
at one end of the housing chamber 22.
er coefficient of expansion and as the temperature of the
Thus, the rotor 20 rotates about a ?xed axis with re
pump increases the guides normally would move away
spect to the housing 8, and the pistons 36 are reciprocated
from ?rm contact with the ring.
by being held within the modulator ring 40 which is po
The bearing rings 66 and 40 preferably are constructed
sitioned eccentric with respect to the rotor. The ec 40
of alloy steel to carry the high contact stress and the hous
centricity of the modulator ring is adjustable to vary
ing is constructed of either aluminum or magnesium in
the amount of reciprocation given the pistons and thus
order to minimize weight. Thus the expansion of the
the output of the pump.
aluminum or magnesium case would be nearly double the
To control the eccentric position of the modulator ring
rate of the alloy steel rings and considerable differential
40, it is held within a second outer ring 66 which is
expansion will occur. The thermal expansive backing
located within the housing chamber 22. The outer po
members are designed to have a rate of thermal expansion
sitioning ring 66 supports the inner ring by a series of
so that the difference in expansion with increase in tem
bearing rolls 68 located between the rings. The rings
perature of the pump will be compensated for. The back
are thus concentrically located with respect to each other
and the inner ring is free to rotate with respect to the 50 ing elements 116 and 118 are formed of Te?on, which is
a plastic material sold commercially under the foregoing
?xed outer ring. The outer ring is moved within the
trade name, and which has an expansion approximately
housing chamber 22 by a number of positioning mem
?ve times greater than aluminum or steel. The Te?on
bers with the primary positioning members being con
pads 116 and 118 are held within caps 120 and 122 which
trolled by the pressure of the delivery ?uid.
As the rotor 20 rotates and the pistons 36 reciprocate, 55 are threaded and screwed into sockets in the sides of the
housing. O-ring gasket seals 124 and 126 are provided
?uid is taken in and expelled from the cylinders 34
to prevent leakage from the housing chamber 22. Thus,
through the ?uid delivery passageways 38. For the in
the bearing members 112 and 114 continually hold the
take stroke of the pistons 36, the passageways 38 are in
58 held between an inner race 60 and an outer race 62.
ring 66 snugly within the housing chamber preventing vi
communication with an elongated arcuate slot 70 in a
valve plate 72 which is spring pressed against the ?at 60 bration and chatter, and permitting the ring to be moved
laterally to shift the modulating ring 40.
end face 74 of the rotor. Communicating with the elon
gated arcuate intake slot 70 is an intake passageway 76
which is formed by a connector 78 and which has an
axis parallel to the axis of rotation of the pump. The
arcuate slot 70 has substantially the same area as the
outside diameter of the connector tubes 78, so that
changes in inlet pressure will have no effect on the valve
In other words, the difference between the diameter of
the outer ring 66 and the diameter of the housing is taken
up by the guide assemblies 108 and 110. This difference
?ows into the connector tube 78.
their expansion in many constructions can be ignored.
will change with temperature change. The difference
change must be equaled by the expansion and contraction
of the pads 116 and 118 plus the expansion and contrac
plate rubbing force.
tion of the guide bearings 112 and 114. Since the expan
sion and contraction of the guide bearings 112 and 114 is
The connector tube 78 has an outer diameter which
permits it to ?t snugly within an opening 86 within the 70 small by comparison with the pads 116 and 118, because
they are made of metal which has a low coei?cient of ex
valve plate and Within an opening 82 in the housing cap.
O~ring seals 84 and 86 prevent the leakage of ?uid as it
pansion as compared with the Te?on pads 116 and 118,
The cap has an in
When the ring 66 and the housing are selected, the dif
ternally threaded passageway 88 through which the in
take ?uid ?ows on entering the housing. For the de 75 ference in expansion per degree of temperature change
3,028,814
5
6
can readily be determined, from either measurement or
the position of the feathering piston 160 by an output
pressure control valve assembly 180. The output pres;
from known expansion of annular members formed of
given metals. The length of the pads 116 and 118 is then
chosen to substantially equal said dilference in expansion
per degree of temperature change. When said difference is
a larger ?gure, the pads will be made longer, and when
said difference is a smaller ?gure the pads are made short~
er. Then, at temperatures between room temperature and
operating temperature, the pads will ?ll the space caused
sure control valve 180 has a valve body 182 which is
threaded into a threaded opening 184 in the housing
cap 24, as shown in FIGURE 4. The ?ow through the
valve passesv through an ori?ce 186 at the inner end
which communicates withthe pump discharge passage
way 104. The ori?ce is'formed in an inset ?tting 188 in
the end of the valve 180. The ori?ce leads to a cylin
by the difference in expansion between‘ the ring and hous 10 drical chamber 190 in which is located the control pis
ing, but they will not over?ll this space and the ring will
ton 192. The piston is slidably movable within the
not have play but also will not bind. If the expansion
chamber 190 to open the lateral passageway 194 and
and contraction of the metal bearings 114 and 116 is to be
permit a ?ow of pump delivery ?uid through the pass
taken into account, with metal bearings of a known co
ageway into an annular groove 196 around the valve
efficient of expansion, it is a simple matter to select a coni 15 body. The groove is in direct communication with the
bination of lengths of pads ‘and bearings which will to
passageway 174 leading to the chamber behind the
gether yield an expansion equal to said expansion dilfer
feathering piston 160. Thus, when the control piaston
ence between the ring 66 and the housing 8. As an alter~
192 is permitted to slide rearwardly and uncover the
native, a given bearing length may be selected, and when
lateral passageway 194, pressurized ?uid will be per
the Te?on pad length is determined, caps 120 and 122 are 20 mitted to move the feathering piston 160, FIGURE 3,
provided to support the pads so that the bearings are in
against the ring 66 to move the modulating ring 40 to
engagement with the ring 66.
ward at position of decreased pump output. This will
A lateral pressure of a constant force is applied to the
ring 66 by a spring biasing element 128. The biasing ele
ment includes a hollow cap 130 threaded into an opening
in the side of the housing 8, and having a cylindrical in
wardly facing opening 132 in which slides a piston 134
occur when the pump output reaches the predetermined
pressure at which the output is to be maintained. When
the pressure drops below the predetermined constant
pressure, the piston 192, FIGURE 4, will cover the
lateral passageway 194. Fluid will then bleed out of
biased toward the ring 66 by a spring 136. The spring
the chamber 170 behind the feathering piston .160
136 applies a constant pressure against the ring urging
through the passageway 174, through lateral passage
the modulating ring 40 toward a position of maximum 30 way 194, and through an axially extending passageway
displacement of the pump. Thus, when no other forces
198 through the valve body. This passageway leads to
are applied, such as when the pump is ?rst started, a maxi
a spring chamber 200 in the valve body and the ?uid
mum delivery will be received until pressure is built up.
will ?ow into the space 202 behind the piston and out
Another lateral force is applied in the direction to urge
through a lateral passageway 204 in the valve body
the modulating ring 40 toward a position of maximum ca 35 which communicates with an opening 206 draining into
pacity of the pump by a positioning piston assembly 138.
the housing chamber 22. The ?uid pressure behind the
This assembly is held within a hollow boss 140 projecting
feathering piston 160 will thus be relieved, .again per
from the housing 8 and facing inwardly toward the hous~
mitting the ring 66 to move the modulating ring 40 to a
ing chamber 22. A piston 142 is slidably mounted within
position of increased discharge. A balance is maintained
a lining 144 within the boss. The piston 142 has its inner
end received Within a hollow sliding cup 145 also slidably
piston 192. During starting, it will be noted in FIGURE
at the proper discharge pressure by movement of the
mounted within the lining 144. The piston supporting
4 that the piston 192 covers passageway 194 and opens
bleed passageway 206. Further, it will be noted from
casing chamber 22, and is held in place by threads 146.
FIGURE 4 that piston 192 will cover the lateral pass
An O-ring seal 143 prevents leakage of pressurized ?uid 45 age 204 to seal the spring chamber 200 when pressurized
from a space 150 behind the piston 142.
v
?uid is being directed up through the passageway 174 to
the feathering piston.
,
1
The space or chamber 150 behind the piston is ?lled
with ?uid communicated thereto from the output of the
Control of the valve piston 192 is accomplished by a
lining 144 is threaded into the boss 140 from inside the
plunger 208 controlled by a spring 210 positioned in the
pump, ‘and is, therefore, at the pump delivery pressure.
As shown in FIGURE 4, a ?uid pressure line 152 leads 50 spring chamber 200. The plunger 208 is slidably
through a ridge 154» in the housing cap 24 and communi
mounted in the spring chamber 200 and has openings
cates at one end with the discharge passageway 104 from
211 to permit the free flow of ?uid to either side of the
the pump'and at the other end with a lateral passageway
plunger. The plunger has ‘an extension which engages
156 which leads to the space 150 behind the piston. Thus,
the piston 192 so that the piston is urged toward the end
the hollow sliding cup 145, is pressed against the ring 66
of the valve body 182 by the spring, and urged in the
opposite direction by the pressure at the end of the pis
in accordance with the output of pressure of the pump,
and tends to urge the modulating ring 40 to a position of
full pump output.
A lateral force is applied ‘against the ring 66 in an op
ton in the chamber 190.
The spring pressure against the piston 192 is adjusted
by a pressure adjusting cap 212 adjustably threaded onto
posite direction by a feathering piston assembly 158. A 60 a threaded end 213 of the valve body. The cap 212 has
feathering piston 160 is slidably held within a cap 162
a spring engaging member or plunger 214, which is held
threaded into the open end of a boss 164 on the housing
within a cup 216 with the bottom of the cup carrying
an expansion pad 218.
8. Seals 166 and 168 prevent leakage of pressurized ?uid
from the chamber 170 behind the feathering piston 160
As the temperature of the parts of the pump increase,
land to the housing chamber 22. The piston is provided 65 the spring modulus of the spring 210 decreases, thus de~
with a piston ring 172 which prevents ?uid leakage past
creasing the pressure of the spring against the piston 192.
the piston. The piston 160 bears directly against the ring
To compensate for this and insure a constant spring
66, and its position varies to vary the position of the modu
pressure against the piston 192, the pad 218 is formed
lating ring 40 with variance in discharge pressure of the
of Te?on or a like material which has a coe?icient of ex
pump. The pump discharge ?uid is communicated to the
pansion su?icient to close the coil compression spring
chamber 170 behind the feathering piston 160 through a
210 a distance so that its force ‘against the piston 192
passageway 174 formed in a rib 176 on the housing cap
will remain constant regardless of the temperature of
24. A lateral passageway 178 leads the ?uid to the cham
the pump. Thus, as the temperature of the pumpin
ber 170.
creases and modulus of the spring decreases, the spring
Fluid is admitted to the passageway 174 to control
will be shortened due to the expansion of the thermal
7
expansive pad 218. The function of this pad will re
main the same for any setting of the pressure adjusting
cap 212. It will be understood, however, that the thicl’
ness of the pad chosen may be varied to suit the pres
sure setting in order to get the proper thermal compen
sation.
.
The pump is adapted to be used for supplying a sys~
tern wherein the demand for pressurized ?uid is inter
8
3, which receives pressure ?uid within the piston chamber
150 from the pump output. A variable positioning pres
sure is applied by a feathering piston 166 which inter~
mittently receives discharge ?uid from the pump by the
action of a control valve 180. The feathering piston 160
is larger than the piston 142 and therefore, applies a
greater force.
A control valve 180 has a valve piston 192 controlled
by a spring 216 and alternately moves to expose a lateral
mittent, so that a constant pressure will be delivered by .
the pump under varying quantities of delivery. Under 10 passageway 194 to permit a ?ow of ?uid up to the feather
some circumstances, the system will require no ?uid and
the pump will thus operate under zero delivery condi
tions. The friction of the pump parts naturally creates
an amount of heat and this heat is dissipated during
ing piston. A thermal expansive pad 218 maintains the
pressure of the valve spring 210 constant regardless of
temperature change. During periods of minimum pump
delivery, a bypass of ?uid through the housing chamber
normal operation and absorbed by the ?uid passing 15 22 is permitted the by-pass valve 220 having the plunger
226 which is positionally controlled by the ring 66.
through the pump. Under conditions of no delivery, a
Thus, it will be seen that we have provided an improved
special by-pass ?uid is directed through the housing
constant pressure variable displacement pump which
chamber 22 to provide the cooling necessary.
meets the objectives and advantages hereinbefore set forth.
The by-pass ?uid is provided by a bypass valve as
sembly 220 supported within a hollow boss 222 at the 20 The pump has very important basic advantages in that it
can be constructed in a small size for operation at a high
side of the housing 8. A valve body 224 is threaded
speed, and has a potential long life.
into the hollow boss 222 from within the housing 8.
It will be understood that while the rotor and pumping
The valve body carries a valve plunger 226, which is
means are shown in the form of a member carrying re
reciprocable within the body to control ?ow through a
25 ciprocating pistons that other types of pumping means
lateral passageway 228.
may be employed utilizing certain features of the inven
When the valve plunger 226 is in the position shown,
tion. It will also be recognized by those skilled in the
the passageway 228 is closed. When the valve plunger
art, that certain other changes may be made in various
226 moves laterally, or to the left, as shown in FIGURE
operating elements retaining the advantages of certain ele
3, the passageway 228 is opened, and a ?ow of ?uid
ments embodying the principles of the invention.
will be permitted from the delivery passageway 104 of
The pump is compact and capable of accurate control
the pump, FIGURE 4, to the housing chamber 22. The
with high speed operation and substantial delivery out
?uid will ?ow through a by-pass passageway 230, formed
put. It will be recognized, that in certain circumstances,
in a rib 232 in the housing cap 24. A lateral pas
different positioning devices for the modulator ring can
sageway 234 leads from the rib passageway 230 into an
annular groove 236, FIGURE 3, communicating with 35 be employed. Further, various elements of the pump may
be used in different operating circumstances, although the
the valve passageway 228. Fluid will ?ow through the
pump is shown in its preferred environment.
hollow core 238 of the valve plunger 226 and through
We have, in the drawings and speci?cation, presented
the port 240 in the base of the cup 242 which is slidably
a detailed disclosure of the preferred embodiments of
mounted within the valve body. The cup 242 supports
the ?ared base of the valve plunger 226 and the ?ared 40 our invention, and it is to be understood that we do not
intend to limit the invention to the speci?c form disclosed,
‘base receives the force of a coil compression spring 244
but intend to cover all modi?cations, changes and alter
bearing against the end of the hollow chamber 246 in
native constructions and methods falling within the scope
the valve body 224.
of the principles taught by our invention.
It will be observed that a position of the valve plunger
We claim as our invention:
226 is controlled by the position of the outer ring 66 45
1. In a variable displacement pump the combination
which bears against the cup 242 holding the valve plunger
comprising, a pump rotor carrying pumping means, an
against its spring 244. When the ring 66 is in the posi
annular modulator ring positioned with its axis parallel
tion wherein the pump is delivering ?uid, the plunger
and eccentric with respect to the rotor and operating
226 closes the ori?ce 228. However, when the ring 66
the pumping means with rotation of the rotor within the
moves to the left from the position as shown in FiGURE
ring, a housing de?ning a chamber for enclosing the ring
3, to a location where the modulating ring 40 is in a
and rotor for movement of the ring in the housing in a
location of minimum delivery, the valve plunger 226
radial direction for changing the distance between the
will uncover the passageway 228, and a ?ow of by-pass
ring axis and rotor axis, pump output control means for
cooling ?uid will be permitted from the delivery pas
shifting the ring radially within the housing, bearing guides
sageway of the pump. Since this delivery passageway
supported on the housing and engaging the peripheral
is connected to a supply line or supply tank, or the like,
outer surface of the ring and located on opposite sides
a constant supply of ?uid will be available for cooling
of the ring laterally of the path of radial shifting move
the pump.
ment of the ring, and a backing member between the hous
As shown in FIGURE 1, the by-pass cooling ?uid will
be permitted to escape from the housing chamber 22 60 ing and at least one of the bearing guides non-yieldably
holding the guides in engaging supporting non-binding
through a passageway 247 in the pump housing 8 leading
contact with the ring and having a thermal expansion
to an internally threaded drain opening 248. The by-pass
rate equal to the difference between the expansion rate of
?uid will, of course, permit lubrication for the roller bear
the housing and the ring so that the ring will be sup
ings 68 between the rings 40 and 66, and the ball bear
ported between the guides at varying temperatures with
ings supporting the rotor 20.
65 out the formation of spaces between the ring and guides
As a brief summary of operation, the rotor 20 is driven
and without binding the ring.
in rotation within the modulator ring 40 which is mounted
to be moved eccentrically with respect to the rotor. The
2. In a variable displacement pump the combination
comprising a pump carrying a radially reciprocating pump
modulator ring rotates with the rotor, being carried within
bearing rollers 68 held within an outer ring 66. The 70 element, an annular modulator ring positioned with its
axis parallel and eccentric with respect to the rotor axis
inner modulator ring transmits radial forces to pistons 36
and operative to reciprocate the pump element with rota
carried in radially extending pump chambers 34 through
tion of the rotor within the ring, a housing de?ning a
axially extending rollers 42.
chamber for enclosing the ring and rotor for movement
The outer ring 66 is laterally positoned to vary the
of the ring in the housing in a radial direction for chang~
output of the pump by a positioning piston 342, FlGURE
8,028,814
10
ing the distance between the ring axis and rotor axis, said
ring and said housing formed of diiterent materials with
different coefficients of thermal expansion, pump output
control means for shifting the ring radially within the
housing, bearing guides supported on the housing and
engaging the peripheral outer surface of the ring and lo
cated on opposite sides of the ring laterally of the path
of radial shifting movement of the ring, and backing mem
temperatures without the formation of spaces between the
ring and guides and without binding the ring.
4. A combination of elements in a variable displace
ment pump in accordance with claim 3 in which the back
ing members are formed of Te?on.
References Cited in the ?le of this patent
UNITED STATES PATENTS
bers between the housing and each of the guides non
yieldably holding the guides in engaging supporting non 10
binding contact with the ring and having a thermal ex
pansion rate equal to the diiference between the expansion
rate of the housing and the ring so that the ring will be
supported between said guides at varying temperatures
without the formation of spaces between the ring and 15
guides and without binding the ring.
3. In a variable displacement pump the combination
1,325,434
Ott _________________ __ Jan. 15, 1935
2,006,112
Heid ________________ __ June 25, 1935
2,143,937
Chandler ____________ __' Jan. 17, 1939
2,271,336
2,273,468
2,292,181
2,309,833
Goldsmith ___________ __
Ferris _______________ ..
Tucker ______________ ..
Elze ________________ __
2,345,952
comprising, a pump rotor carrying radially reciprocating
pump elements, an annular bearing ring having an outer
race and an inner race positioned with its axis parallel 20
and eccentric with respect to the rotor axis and opera
tive to reciprocate the pump elements with rotation of
the rotor within the ring, a housing de?ning a chamber
for enclosing the ring and rotor for movement of the ring
in the housing in a radial direction for changing the dis 25
tance between the ring axis and the rotor axis, pump out
put control means engaging the ring for shifting the ring
radially within the housing, bearing guides supported in
the housing and engaging the peripheral outer surface of
2,374,592
2,422,864
2,506,974
2,525,498
2,547,645
2,612,418
2,646,755
2,680,412
2,729,165
2,823,619
2,845,941
161,911
443,041
953,223
cesses in the housing supporting the bearing guides, and
backing members in each of the recesses behind the hear
ing guides non-yieldably holding the guides in engaging
supporting non-binding contact with the ring ‘and having
a thermal expansion rate equal to the difference between
the expansion rate of the housing and the ring so that
the ring will be supported between said guides at varying
Jan.’ 26,
Feb. 17,
Aug. 4,
Feb. 2,
1942
1942
1942
1943
I Smith _______________ __ Apr. 4, 1944
Ernst _______________ ..- Apr. 24,
Taylor ______________ .._ June 24,
Sorensen _____________ __. May S,
Naylor et a1 ___________ __ Oct. 10,
Horton ______________ .. Apr. 3,
Krotz ______________ __ Sept. 30,
Joy _________________ __ July 28,
Entwistle ____________ __ June 8,
Kremer ______________ __ Jan. 3,
May ________________ __ Feb. 18,
Wagner ______________ .. Aug. 5,
1945
1947
1950
1950
1951
1952
1953
1954
1956
1958
1958
FOREIGN PATENTS
a the ring and located on opposite sides of the ring laterally 80
of the path of radial shifting movement of the ring, re
Todd _______________ __ Dec.-16, 1919
1,988,213
Great Britain _________ __ Apr. 21, 1921
Great Britain ________ .._ Feb. 20, 1936
Germany ____________ .... Nov. 29, 1956
OTHER REFERENCES
w
Technical Service Bulletin No. 13, “Te?on,” DuPont ,
Company, 350 Fifth Ave., New York 1, N.Y. April‘ 1,
1949.
“Te?on Components and Coatings,” Product Engineer~ 7
ing, September 1952, pages 149-153,
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