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Патент USA US3078817

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Feb- 26, 1963
J. o. BYERS, JR
HYDRAULIC BALANCING SYSTEM FOR ROT
DISPLACEMENT FLUID HANDLING
Filed July 17, 1958
3,078,808
Y POSITIVE
VICES
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4 Sheets-Sheet 1
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405% 94
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INVENTOR.
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A 7'7'ORA/EY
Feb. 26, 1963
J. 0. BY
s, JR
3,078,808
HYDRA L C BALANCING SYS.
F
ROTARY POSITIVE
SPLACEMENT FLUID HAN ING DEVICES
Filed July 17, 1958
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4 Sheets-Sheet 2
INVENTOR.
‘M245 0. Emma/A’.
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Feb. 26, 1963
J, 0 .
BYERS, JR
3,078,808
HYDRAULIC BALANCING SYSTEM FOR ROTARY POSITIVE
DISPLACEMENT FLUID HANDLING DEVICES
4 Sheets-Sheet 5
Filed July 17, 1958
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Feb. 26, 1963
J. o‘ BYERS,
3,078,808
JR
HYDRAULIC BALANCING SYSTEM F OR ROTARY POSIT IVE
8 DISPLACEMENT FLUID HANDLING DEVICES
4 S heats-Sheet 4
Filed July 1'7, 195
JA/VZJ 0. 53112-3323”.
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BY
United States Patent O?tice
3,078,808
Patented Feb. 26, 1963
1
2
3,073,868
camming surface 12; and an inner member B having a
plurality of radially outwardly extending cylinder bores
HYDRAULIC BALANCENG SYSTEM FOR RUTARY
POSITIVE DISPLACEMENT FLUKE) HANDLING
14 in which individual pistons 16 are positioned in a
manner to be reciprocated by the camming surface 12
DEVICES
James 0. Byers, Ilia, St. Joseph, Mich, assignor to The
during relative rotation of the inner and outer members.
The casing member in the present instance is a stationary
Filed July 17, 1958, Ser. No. 749,133
one, and the internal member B is adapted to be rotated
5 Claims. (Cl. 103-161)
relative to the camming surface 12. by an axially posi
tioned shaft 18 which extends through one end wall 249
The present invention relates to a ‘balancing piston
of the casing member A. The inner end of the shaft
10
arrangement for rotating positive displacement ?uid han
18 is journaled in a sleeve bearing 22 that is supported
dling devices having a plurality of chambers, individual
in an axial bore 24 in the opposite end wall 26 of the
ones of which are alternately pressurized and depressur
casing member A; and the projecting end of the shaft 18 is
ized; and more particularly to a pressurizing arrangement
suitably
journaled and sealed with respect to the end
for a hydraulic balancing piston in radial piston pumps
wall 20. The center portion of the shaft is suitably
and motors.
splined to the inner rotor member B substantially on the
An object of the present invention is the provision of a
radial plane passing through the cylinder bores 14.
new and improved system for supplying pressure to a
Each of the individual pistons 16 are provided with a
balancing piston from the individual ?uid pressurizing
ball 28 for engagement with the camming surface 12; and
chambers of a rotary positive displacement device, in
upon rotation of the shaft 18, centrifugal force causes
dividual chambers of which are periodically pressurized
the individual pistons 16 to be biased radially outwardly
and then depressurized, and in which pressurizing system
into ?rm engagement with the cumming surface 12.
for the balancing piston, no moving parts are utilized.
Relative rotation between the inner and outer members
Another object of the present invention is the provision
causes the pistons 16 (of which there are 7 in the present
of a new and improved pump and/or motor having a
pump) to be reciprocated in their cylinder bores 14. By
plurality of radial piston chambers therein which are 25 properly communicating each cylinder bore 14 to a supply
alternately pressurized and depressiurized, and each of
of ?uid at suction pressure when its piston 16 is moving
which chambers communicate with the balancing piston
Bendix Corporation, a corporation of Delaware
radially outwardly, and by properly communicating each
through substantially identically constructed ?ow restric
tions or ori?ces.
cylinder bore to the discharge passages of the pump when
‘
its piston 16 is moving radially inwardly, a pumping action
is established. By successively Valving each of the cylin
A further object of the invention is the provision of
a new and improved pump and/or motor of the above
der bores to the suction and discharge connections of
the pump during their respective suction and discharge
strokes, a continuous ?ow of ?uid is achieved.
A still further object of the present invention is the pro
Inasmuch as the position and duration of the suction
vision of a new and improved pump and/or motor of 35 and discharge strokes for each cylinder are ?xed by the
the above described type having an odd number of ?uid
con?guration of the camming surface 12; and inasmuch
pressurizing chambers greater than five.
as the camming surface is held stationary with respect
The invention resides in certain constructions and com
to
the casing member A, the start of the suction stroke
binations and arrangements of part-s; and further objects
for each cylinder will take place when each cylinder moves
and advantages will become apparent to those skilled in
precisely the same position relative to the casing member
the art to which the invention relates ‘from the following
A, and ‘will continue over precisely the same circular arc
description of the preferred embodiment described with
of the casing member. Likewise, the discharge stroke
reference to the accompanying drawings forming a part
for each cylinder starts when each moves into precisely‘
of the speci?cation, and in which:
described type wherein the ?ow restrictions produce
laminar ?ow.
FIGURE 1 is a ‘cross sectional view taken approximate
ly on the line 1—1 of FIGURE 3 of a hydraulic pump
45 the same position and continues over the same circular
embodying principles of the present invention;
FIGURE 2 is a cross sectional view taken approximate
ly on the line 2—2 of FIGURE 1, with the rotor in a 50
different angular position from that shown in FIGURE
1 to better illustrate the Valving cycle of the pump;
FIGURE 3 is an end view of the pump shown in FIG
arc of the casing member. Fluid can be added to and
taken from each of the individual cylinders, therefore, by
successively Valving each of the cylinders to suction and
discharge passages in the casing member when the cylin
ders are properly positioned in the housing member rela
tive to the camming surface 12.
The pump shown in the drawing has a generally ellip
URE 1 having parts broken away and sectioned approxi
mately upon the line 3-~3 of FIGURE 1;
FIGURE 4 is an end view of a porting plate shown
in FIGURES 1 and 2;
tically shaped camming surface 12, so that each individual
‘cylinder has two pumping cycles during each revolution
displacement hydraulic pump capable of producing pres
In order that sealing angular alignment of these surfaces
of the rotor member B. Valving of each individual pump
ing cylinder to the suction and discharge connections of
the pump is accomplished by a rotary disc valve arrange
FIGURE 5 is a cross sectional view taken approximate
ment formed between one end of the rotor member B.
ly on the line 5—5 of FIGURE 4;
FIGURE 6 is a cross sectional view taken approxi 60 and the end wall 26 of the casing member A. The rotary.
disc valve arrangement shown generally comprises a pair
mately on the line 6-6 of FIGURE 1; and
of matching Valving surfaces which slidingly sealingly
FIGURE 7 is an isometric view of one of the ori?ce
engage each other, and one of which surfaces 30 is formed
forming plugs shown in FIGURE 6.
in and rotated by the rotor member B while the other
While the invention may be otherwise embodied, it is
herein shown and described as embodied in a positive 65 Valving surface 32 is supported on the casing member A.
sures in the neighborhood of approximately 1,500 psi.
can be accomplished easily when the pumps are made on
The pump is intended for use in the central hydraulic
systems of farm tractors and the like.
a mass production basis, the matching Valving surfaces
30 and 32 are spherically shaped; and in order that the
The pump shown in the drawing generally comprises 70 Valving operation can be adjusted relative to the camming
an outer casing member A having an internal chamber
10 therein containing a radially inwardly facing annular
surface to 'vary the discharge of the pump (as will later
be described), the Valving surface 32 is formed as a Sur
3,078,808
a
4
face of a‘ port plate 36 which ‘can be angularly positioned
The port plate 36 slidably sealingly engages a planar
relative to the casing member A.
The pump shown in the drawing is intended to handle
surface 62 in the end Wall 26 of the casing member A
in which are located a pair of diametrically opposed dis
an oil having considerable lubricating qualities, and has
charge ports 64 with which the arcuately shaped dis
been‘ designed to permit ?uid from the suctioned con C21 charge ports 52 of the porting plate always communicate.
Iiectio‘n 38 of the pump to be distributed through an
annular groove 46 in‘ the end wall 26 to the internal
chamber 10 of the pump. The valving surface ‘30 of the
rotor member B is provided with a plurality of identically
The ports 64 are formed by longitudinally drilled pas
sageways 66 which are intersected by a transverse drilling
66 which in turn is intersected by the discharge port 70 of
the pump.
shaped circular ports 42 each of which communicate
As previously indicated the port plate 36 is made ar
cuately movable in order that the pumps displacement,
are uncovered by the port plate 36 to permit ?uid from
or quantity of ?uid which will be delivered by the pump
the internal chamber 10 to be drawn into the cylinder
during one revolution of the rotor, might be varied. By
rotating the port plate 36 in a clockwise direction from
bores during their suction strokes. The ports 42 must,
therefore’, be sealed off from the internal chamber 10 15 the position shown in FIGURE 2, the individual circular
during. their discharge strokes; and inasmuch as the cam
ports‘ 42 will be‘val'ved off by the leading portion 48
of the valving surface 32 prior to the time that the radial
rhing surface 12 causes these discharge strokes to be
piodu‘c'ed over two diametrically opposite‘ 90° arcs, the
ly outward stroke of the individual pistons 16 have been
port plate 36 has an “hour glass type” of con?guration,
completed; so that only a fraction of each cylinder bore’s
as‘ best seen in FIGURES 2 and 4, capable of sealing off 20 maximum displacement is ?lled with ?uid from the inlet
the ports 42 from the internal chamber 10 over two di
of the pump. The individual circular ports 42 will
with a res ective cylinder bore 14; and these ports 42
amet‘rically‘ opposite 90° arcs.
thereafter be v'alved off from both the suction and dis
Referring now to FIGURE 2 of the drawings, the port
plate 36 is shown therein in its position providing maxi
displace'nient for the pump. Assuming counter
clockwise rotor rotation as seen in FIGURE 2, the pis
tons 16 stait their discharge s'tro'kes' when the center line
of their cylinder bores 14 become coincident with the
major ‘axis 44 of the cammi'ng siirfacc. “When the center
charge connections of the pump for approximately 3°
of rotor rotation; and thereafter the individual circular
ports 42 will be connected with the arcuately shaped dis
charge port 52 in the port plate 36 so that ?uid will be
taken into each cylinder from the discharge of the pump
for‘ the remainder of each piston’s suction stroke. Inas
much as the port plate 36 is proportioned to connect
the individual circular ports‘ 42 to the discharge of the
pump for approximately 87° of rotor rotation, move
ment of the center line of the cylinder bores 14 past the
major axis 44 of the camming surface causes ?uid to be
forced out through the discharge ports 52 and 64. Dis
charge through these ports continues past the major axis
44 through an angular displacement of the remainder
line of the ports 42 become coincident with the major
44, ‘the trailing edge of the ports 42 become coinci~
dent with the leading edge 46 of the leading sealing sur
face 48 of each half of the port plat'e’s valving surface
32, and the ports 42 become sealed on from both the suc
tioii and discharge connections of the pump for the fol~
lowing approximately 6° of rotor rotation. Approxi
mately 3° of rotor rotation after the cylinder bores 14
pass the major axis 44, the leading edge of the circular
of 87° of rotation, which will now terminate before the
cylinder bores 14 reach the minor axis 56. Thereafter
the ports 42 will be valved off from both the suction and
ports 42 become coincident with the leading edge 50 of
an arcuately shaped discharge port 52 that is centrally 40 the discharge of the pump for approximately 3°; and
positioned within each half of the port plate 36. There
will then be communicated with the suction of the pump
after subsequent rotation of the rotor member causes the
during the remaining portion of the discharge stroke of
circular ports to start the opening operation of the dis
the individual pistons 16. It will therefore be seen that
charge ports 52 which continues for approximately 32°
of rotor rotation. The leading edge 50 and the trailing
by angularly displacing the porting plate 36, part of the
edge 54 of therdischarge ports 52 are formed to the
same ‘radius as the circular ports 42, and about centers
which, are spaced 23° of rotation. Thereafter the lead
ing edge of the circular ports 42 begin to move past the
trailing edge 54 of the discharge port 52; and after ap
proximately 32° of further rotation, the trailing edge
of the circular ports 42 become coincident with the trail
suction stroke for each cylinder bore 14 will be taken up
with ?uid obtained from the discharge ports of the pump;
and a corresponding ?uid displacement of the discharge
stroke for each cylinder bore 14 will be passed to the
suction of the pump. By this expedient the total quan
tity of ?uid passing the outlet of the pump per rotor
revolution can be varied or controlled by adjusting the
angular position of the porting plate 36 relative to the
camming surface 12.
close on the ports 42 from both the suction and dis
The pump shown in the drawing is provided with auto
charge of the pump. This occurs as the center lines of 55 matic means for angularly positioning the port plate 36
the individual cylinder bores 14 become coincident with
in a direction decreasing the displacement of the pump
ing edge of the arcuately shaped discharge port 52 to
the minor axis 56 of the camming surface 12; and the
circular ports 42 are valved off from both the suction
and discharge of the pump thereafter for approximately
3 ‘’ of rotor rotation.
The leading edge of the ports 42 become coincident
with the trailing ‘edge 58 of the trailing portion 60 of the
valving surface 32 after the cylinder bores 14 have moved
approximately 3° past the minor axis 56 of the camrning
when the pressure in its discharge passages exceeds a
predetermined pressure, which in the present instance is;
approximately 1,500 psi. The automatic means ‘C for
60 positioning the port plate is best seen in FIGURE 3
of the drawings; and generally comprises a cylindrically
shaped slide member 72 which is positioned in a trans
verse bore 74 in the cover plate 26. ‘The slide member
72 is notched out as at 76 to receive a pin 78 that ex
surface 12; and the individual circular ports 42 will re 65 tends through an arcuately shaped opening 80 within the
main iii communication with the internal chamber 10 or
cover plate 26 that communicates the bore 74 with the
suction passages of the pump until the trailing edge of
back of the port plate 36. Pin 73 is rigidly connected
the ports 42 become coincident with the leading edge 46
to the port plate 36; and the port plate 36 is held in its
of the other half of the valving surface 32——-which occurs
maximum displacement producing position, shown in
70
when the center line of the cylinder bores 14 become
FIGURE 2, when the inner end of the slide member 72
coincident with the major axis 44. This completes one
is held into engagement with a shoulder 82 formed on
suction and discharge cycle as occurs over 180° of rotor
the inner end of the transverse bore section 74. The
rotation; and thereafter the cycle is repeated with respect
slide 72 is held in this position by a coil spring 84 which
to the other half of the porting plate 36 during the sec
is biased against an abutment plate 86 positioned against
75 the outer end of the slide member 72 and a closure mem
ond 180° of rotor rotation.
3,078,808
6
5
her 88 which is suitably held in place in the outer end of
the transverse bore 74.
.
The slide member 72' is adapted to be moved in a direc
tion reducing the displacement of the pump by a piston
99 that is positioned in a smaller diameter bore section
ciency. The valving surfaces 30 and 32 must therefore
be biased together by an amount of force which will pre
vent excessive leakage between the valving surfaces. In
order that the pressure seepage between the valving sur
faces might be con?ned to as small an area as possible, and
thereby decrease the amount of force tending to bias the
valving surfaces apart, an annular groove 120 is formed
is actuated by pressure supplied to its inner surface.
in the surface 36 a short distance radially outwardly from
Pressure actuation of the piston 90 is in turn controlled
the radially outer edge of the arcuately shaped discharge
by a slide valve structure 94 which is adapted to com
municate the bottom end of the piston 90 to the suction 10 ports 52. Similarly, an axially positioned recess 122 is
formed in the rotor member B with its radially outer edge
pressure of the pump until such time as the discharge
positioned a short distance radially inwardly from the
pressure of the pump reaches a predetermined level of
92 in the bottom end of the bore 74; and which in turn
approximately 1,500 psi. Thereafter, the slide valve
inner edge of the arcuate shaped discharge ports 52. It
will therefore be seen that pressure forces upon the port
structure 94 is moved to modulate discharge pressure of
the pump to the cylindrical piston 96 causing the slide 15 plate are con?ned to its area bounded by the annular
groove 120, the axially positioned recess 122 and its
member 72 to be moved outwardy compressing the spring
leading and trailing edges 46 and 58 respectively. A full
84 and moving the pin 78 in a direction decreasing the
discharge pressure will be exerted against the rotor mem
displacement of the pump.
ber B on areas de?ned by the arcuately shaped discharge
The slide valve structure 94 is positioned in a bore 96
which intersects another small diameter bore 98 that 20 ports 52 and the pressure distribution on the remainder
of the area bounded as previously set forth, will vary from
communicates with the inner end of the bore section 92.
substantially full pump discharge pressure adjacent the
The slide valve structure is provided with a pair of spaced
arcuate opening 52 to substantially suction pressure
lands 100 and 162 which when properly positioned will
around the outer edges of the area previously set forth.
just straddle the bore 98' and close off the portions of
the bore 96 which lie on opposite sides of the bore 98 from 25 An approximation of the force biasing the valving surfaces
apart can be obtained by adding: the force obtained by
communication with the cylindrical piston 90. Pressure
multiplying the area which is in sliding sealing engagement
from the discharge passage 66 is fed through two inter
by a pressure which is approximately one half of the dif
secting bores 104 and 106 to the inner end portion of the
ference between suction and discharge pressures, and the
bore 96. The outer portion of the bore 96- is communi
cated with the annular suction groove 40 by a longitudinal 30 force obtained by multiplying full discharge pressure to
the area of the arcuately shaped discharge ports plus the
drilling 108; so that either suction or discharge pump
area of all circular ports 42 which are communicated to
pressures can be communicated to the cylindrical piston
pressure.
90 depending upon the positioning of the slide valve struc
According to principles of the present invention, the
ture 94. The slide valve structure 94 is biased inwardly
valving surfaces 36‘ and 32 are forced into sliding sealing
to normally communicate suction pressure to the inner
end of the cylindrical piston 90 by a coil spring 110 which
normally holds an abutment plate 112 that is positioned
against the end of the slide valve member 94 into engage
ment with the bottom end of the counterbore 116 in which
engagement with each other with a generally predeter
mined force by a single balancing piston 124 which in
the present embodiment extends around the shaft 18. The
annular piston 124 is preferably con?ned to an area that
the spring 110 is situated. The spring 110 is compressed 40 is as close as possible to the shaft 18; and in the embodi
a predetermined amount by a plug 118 which is forced
into the outer end of the counterbore 116 and suitably
ment shown in the drawing, is positioned in a counter
bore 126 in the end of the opening in the rotor member B
through which the shaft extends. O-ring seals 128' and
held in place. When a predetermined pump discharge
130 are provided between the annular piston 124 and the
pressure, which in this instance is approximately 1,500
p.s.i. is delivered to the inner end of the bore 96 the slide 45 sidewalls of the counterbore and shaft respectively; and
another O-ring seal 132 is provided in the shaft opening
valve structure 94 is biased outwardly against spring 110
of the rotor member inwardly from the counterbore 126.
to cause the abutment plate 112 to begin to move out of
The outer surface 134 of the annular piston 124 bears
engagement with the bottom end 114 of the counterbore
against an annular abutment or slipper plate 136 which
116. This causes the land 102 to begin to throttle flow
between the exhaust drilling 1G8 and the inner end of the 50 is non~rotatably supported on the end wall 20‘ of the casing
member A surrounding the shaft 18. Fluid under a
cylindrical piston 90; and inasmuch as some leakage al—
function of discharge pressure is admitted to the inner
ways occurs past the lands 1430 and 102 discharge pres
surface of the annular piston 124 to force the annular
sure from the drilling 106 will ?ow past land 1130 to the
piston into abutment with the slipper plate 136 to produce
drilling 98. Inasmuch as outlet flow from the drilling 98
to the exhaust drilling 108 is now being throttled, a con 55 a reaction which holds the valving surface 30‘ of the rotor
member B into sealing engagement with the valving sur
trol pressure is established in the drilling 98 which will
face 32 of the port plate 36. The cross-sectional area of
be of an intensity which depends upon the relative overlap
the annular piston 124 is preferably of such a size so as
being maintained with respect to the lands 1% and 102.
to at all times bias the valving surfaces 30 and 32 together
At a pump discharge pressure of approximately 1,650
p.s.i., pressure on the inner end of the slide valve 94 will 60 by an amount suiiicient to prevent excessive ?ow between
the valving surfaces.
‘
cause the inner land 1110 to be moved out of overlap with
According to the principles of the present invention,
respect to the inner end of the bore 96, and suf?cient
pressure is supplied to the counterbore 126 from the
pressure will be delivered against the cylindrical piston 90
cylinder bores 14 through interconnecting passageways
to move the port plate 36 into its “no ?ow” position.
At pump discharge pressures between 1,500 psi. and 65 1313, one for each cylinder, and each of which passage
ways contain a ?ow restriction or ori?ce therein, so that
1,650 psi. a proportionate pressure will be delivered
against the cylindrical piston 91) to cause the port plate
36 to assume intermediate positions.
flow continually proceeds through those passageways 138
of the cylinders under pressure to the balancing ring,
Pressure from the arcuately shaped discharge ports 52
in the port plate 36 will, of course, tend to ?ow through
the space between the valving surfaces 30 and 32 and will
while at the same time How is proceeding from the bal
ance ring through those passageways 138' which are
tend to bias the valving surfaces apart. Should the sur
pressure behind the balance piston. The number of pas
faces become separated, discharge from the cylinder bores
14 will be short circuited directly to the internal chamber
sageways 138 which are communicated to pressure at any
connected to suction pressure to establish an intermediate
instant will depend upon the total number of pistons in
4-10 thereby greatly decreasing the pump’s hydraulic ef? 75 the pump, and the instantaneous position of the rotor
3,078,808
8
7
AP=pressure drop (discharge to suction)
member B. In any given pump design, there will be a
maximum number of its cylinders which can be com
municated to pressure at any one time, and a minimum
number of cylinders which can be communicated at any
one time. Generally speaking the maximum number can Cl
be ascertained by determining the maximum number of
cylinder centerlines which can overlie the segments of
the cam which produce the discharge stroke; and in the
pump shown in the drawing wherein 7 pistons are shown,
the maximum number will be 4. The minimum number 10
will of course be 7 minus 4 or 3. In a six piston pump the
4\/A—P1=3\/m
16AP1=9AP2
AP1=%GAP2
9iaAP2+AP2=AP
AP1+APZ=AP
AP=Z%5APZ
AP2=1%5A.P
AP1=%5AP
maximum number will be 4, and the minimum number will
be 2.
When three ori?ces ‘are connected to pump discharge
and four to pump suction,
The force tending to separate the port plate 36 from
the rotor B, has been found to vary with rotor speed, and 15
AP1=1%5AP
it has also been found that the pressure that is developed
behind the balancing piston of a given pump will depend
so that the ?uctuation represents 'F/é5AP or 28%.
upon the type of ori?ce that is used in the passageways
Now assume that laminar ?ow ori?ces are used in the
138. It will be remembered that full pump discharge
same pump arrangement, and their ?ow through a
pressure is subjected to that portion of the sliding sealing
20
valving surfaces of the port plate and rotor to which the
discharge port 52 is communicated, and that a pressure
intermediate pump suction and discharge pressure acts
upon the remainder of the sliding sealing valving surfaces.
It will be seen, therefore, that the total force tending to 25
separate the valving surfaces varies throughout the rotor
cycle and depends upon the number and position of rotor
ports 42 communicating with the discharge port 50 of the
port plate. My prior application Serial Number 719,285,
laminar ?ow ori?ce is proportional to its pressure drop:
AP2=%AP and AP1=%AP
?led March 5, 1958, now abondoned, describes an ar~ 30 When three ori?ces are connected to pump discharge and
four to pump suction:
rangement whereby a substantially constant pressure force
is exerted upon the balance piston to oppose the ?uctuat
ing pressure force between the valving surfaces. The
so the ?uctuation here represents 1/7AI" or 14.3% which
present invention provides means whereby a changing pres
is
approximately one-half that for the sharp edge ori?ces.
sure force can be exerted upon the balance piston which 35
The laminar ?ow ori?ces shown as forming the pas
will at all times be more generally proportional to the
sageways 138 of the pump shown in the drawing are
?uctuating pressure force tending to separate the valving
formed by a drilling 140 of comparatively large size—
surfaces.
one for each piston chamber Ill communicating its piston
It has been found that in any given pump, larger pres
sure ?uctuations will be created behind the balance piston 40 chamber 11% with the counterbore 126. Each of the
drillings is of the same size, and each of the ori?ces are
when a sharp edged ori?ceis used in each passageway
conveniently made of the identical size and shape by
138, than is created when an ori?ce producing laminar
pressing identically shaped plugs 14?; into each of the
flow is used in each passageway 138. By changing the
drillings 140. When laminar ?ow ori?ces are to be
shape and construction of these ori?ces, therefore, the
amount of pressure change behind the balancing piston
can be regulated. In the preferred arrangement, it will
usually be desirable to cause the pressure forces on the
balancing piston to be made proportional to the force
tending to separate the valving surfaces. As previously
stated the speed of rotor rotation changes the pressure
forces tending to separate the valving surfaces, but it
will generally be true that the separating forces will vary as
a function of the percentage of valving surface to which
full discharge pressure is communicated. The changes in
separating force will usually be abrupt as a rotor port 42
is brought into communication with the discharge port
50, and the degree of change depends upon the percent
age change in area to which full discharge pressure is
communicated.
Thepump shown in the drawing is provided with seven
pistons, and will alternately bring 4 and then 3 of its
cylinder chambers into communication with the discharge
ports ‘50. In order to qualitatively show the elfect that
ori?ce con?guration plays upon the pressure forces exerted
used, the plugs 142 may be conveniently made by the
method disclosed in my copending application Serial
Number 706,059, ?led December 30, 1957, now Patent
No. 2,952,071, issued December 9, 1959. A plurality of
small coil springs (not shown) will preferably also be
50 interpositioned between the annular balancing piston 124
and the rotor member B to hold the valving surfaces to
gether during the starting operation of the pump when
no pressure is available for causing the balancing piston
to hold the valving surfaces into scaling engagement.
One end of these springs may be positioned in respective
recesses in the balancing piston, while the other end of
each spring may bear against the bottom of the counter
bore 126.
In order to lubricate the sliding surface between the
60 annular piston I24 and the slipper plate 136, a pair of
concentric annular grooves 144 and 146 are provided in
the outer surface 134 of the annular piston. Fluid under
pressure from the counterbore 126 ?ows through a pas
sageway 148 in the annular piston and then through a
against its balancing piston, the following equations are 65 groove 150 in the surface 134 which extends between the
given by way of illustration:
Assume that a sharp edged ori?ce is used, ?ow to the
recesses 144 and 146. The same pressure that is delivered
against the inner edge of the annular piston 124 is there
fore delivered to the sliding surface between the piston
counterbore '126 must at all times be equal to the ?ow
124- and slipper plate 136 to relieve the mechanical hear
out, ‘four equal ori?ces are feeding the counterbore
70 ing forces between these surfaces. The annular area be
while three are bleeding ?ow out, and flow through a
tween the grooves 144 and 146 is sized in such a way
sharp edged ori?ce varies generally as the square root
that the hydraulic forces tending to separate the annular
of the pressure drop:
piston 124 from the slipper plate 136 will at all times
be slightly less than the force against the end of the an
AP1=pressure drop in
75 nular piston 124 positioned in the counterbore ‘126; and
AP2=pressure drop out
3,078,808
Q
as previously indicated the annular piston 124 is so sized
as to hold the valving surfaces 30 and 32 together. Rota
tion of the annular piston 124 relative to the shaft 18 is
prevented by a pin 152 which extends into aligned open
ing 154 and 156 in the piston 124 and rotor member B,
respectively.
Describing now the operation of the pump with the
porting plate 36 in its maximum ?ow producing position
10
produced; and it will therefore be seen that the pump is
capable of adjusting its rate output to correspond with the
consumption of the hydraulic system to which it is con
nected. The precise manner in which angular displace
ment of the port plate 36 reduces the displacement of the
pump has previously been set forth in detail and will not
further be described.
During the operation of the pump, pressure is supplied
from individual ones of the cylinder bores 14 which are
shown in FIGURE 2, ?uid enters through the pump suc
tion 38 to the annular groove 40 where it is distributed 10 producing a pumping action through the passageways 138
to the recess 122 to bias the annular piston 124 into en
uniformly to the internal chamber 10 of the pump. With
the port plate 36 in the position shown in FIGURE 2, the
gagement with the slipper plate 136, and thereby hold
circular ports 42 in the rotor member B will be in com
munication with the internal chamber 10 for substantially
the valving surfaces 3%? and 32 of the rotor and port plate,
respectively, into sliding sealing engagement. As has pre
viously been explained some of the passageways 138 will
be communicated with the pump discharge while others
of the passageways 133 will be communicated to the
the full suction stroke of their pistons 16, and until the
centerline of the bores 14- are coincident with the major
axis 44 of the camrning surface 12. The ports 42 are
valved oif from both the internal chamber 10 and the
discharge port 52. for the next 3° of rotor rotation. At
aproximately 3° of rotation after the centerline of the
cylinder bores have passed the major axis as, the circular
ports 4-2 become communicated with the arcuately shaped
discharge port 52 so that inward movement of the pistons
16 causes ?uid to ?ow out through the ports 42, and the
arcuately shaped discharge port 52 to one of the discharge
ports 64 in the removable end wall 26 of the casing mem
ber. Inasmuch as the camming surface 12 is elliptically
pump suction so that the pressure that is established in
the recess 122, will be a balance as determined by the flow
rates in and out of the passageways 1.33. As has been
previously explained there will be times when four pas
sageways 138 will be supplying ?uid to the recess 122 and
three passageways 138 are conducting flow out of the
recess 122; while at other times three passageways will
be conducting ?ow in and four passageways will be con
ducting ?ow out. The pressure behind the annular piston
124 will therefore vary, and as previously explained, this
fluctuation when using laminar ?ow ori?ces of the type
shaped to produce two pumping cycles during each revo
shown in the drawing will be approximately one-half that
lution of the rotor member, ?ow simultaneously proceeds
through both of the diametrically opposed drilled passage— 30 which would be produced it the ?ow restriction in the
passageways 138 were of the sharp~edged ori?ce type. In
the preferred embodiment of pump shown in the drawing,
the variation in force tending to separate the valving sur
faces 39 and 32, more nearly corresponds with the pres—
ming surface 12, the trailing edge of the circular ports 42
move out of engagement with the arcuately shaped dis 35 sure ?uctuation as produced by the laminar ?ow ori?ces
shown in the drawing; so that the force produced by the
charge port 52 to valve off the cylinder bores 14» from
balancing piston will slightly exceed and be generally pro
both the suction and discharge connections of the pump.
tional to the pressure forces tending to separate the valv
The ports 42 remain sealed off from both of the suction
ing surfaces.
and discharge passages of the pump for the next 3° of
As previously indicated, some of the ?uid supplied to
rotation, or until their centerlines have moved approxi 40
the recess 122 passes through passageway 148 to the
mately 3° or rotation past the minor axis 56; and there
Ways 66 to the transverse drilling 6% and out through the
discharge port 70 of the pump. When the centerline of
the cylinder bores 14 reach the minor axis 55 of the cam
annular grooves 144- and M6 to pressurize the abutting
after the leading edge of the circular ports 52 move past
faces of the annular piston 124 and slipper plate 136 to
the trailing edge 58 of the port plate 36 to establish com
thereby reduce the direct bearing force between these slid
munication with the suction of the pump. The ports 42
remain in communication with the pump suction for ap 45 ing surfaces. As previously indicated the hydraulic force
tending to separate these surfaces is less than the pres
proximately 87" of rotation thereafter; and the entire
sure force on the inner end of the annular piston biasing
cycle will thereafter be repeated with respect to the dia
metrically opposed portion of the port plate 36.
it into engagement with the slipper plate 136, which force
As previously indicated, the amount of ?uid discharged
in turn is greater than the hydraulic pressure forces tend
from the pump can be varied or regulated by rotation of 50 ing to separate the valving surfaces 30 and 32 by an
the port plate 36 with respect to the camming surface 12
amount preventing excessive ?ow therebetween. A con
of the casing member. Angular displacement of the port
tinuing amount of leakage occurs out of grooves 144
plate 36 with respect to the casing member A is accom
and 146, as well as past the O-rings 123, 13% and 132.
plished by the structure best shown in FEGURE 3, and
inasmuch as these flows are derived from the ?uid ?owing
which comprises a slide member 72 that is normally 55 through the passageways 138 into the recess 122, these
biased into its maximum ?ow producing position by the
?ows may be utilized to further tailor t .e balancing pres
coil spring 84. The slide 72 is caused to angularly dis
sure behind the annular piston 12.4 to more nearly ap
place the port plate 36 in a direction reducing the output
proach the pressure forces tending to separate the valving
of the pump when a pressure exceeding approximately
surfaces 30‘ and 32.
1,500 psi. is supplied to the piston 90 which abuts the 60 I have further found that pump designs having odd
inner end of the slide member 72. When the discharge
number of pistons greater than ?ve, as for example, seven,
pressure of the pump exceeds approximately 1,500 p.s.i.,
nine, eleven, thirteen, etc., can be designed to have valv
the spool valve structure 94 moves outwardly to compress
ing surfaces in which the number of cylinder ports which
spring 110 su?iciently to cause land 102 to lap with re
are valved to discharge at any one instant during its
spect to bore 96. Thereafter variable leakage rates pass 65 rotor cycle will not vary by more than one. Laminar
the lands 100 and 102 causes increasing control pressure
?ow ori?ces of the type shown in the drawing can
to be delivered against the piston 90 which in turn causes
therefore be used to good advantage in pumps and/or
the slide 72 to compress spring 84 and rotate the port
motors of these con?gurations, and the pulsations in the
plate 36. The port plate 36 will be rotated by increasing
pressure discharge of pumps having these con?gurations
amounts as the discharge pressure exceeds 1,500 p.s.i.; 70 decreases as the number of cylinder chambers increases.
and when approximately 1,650 p.s.i. discharge pressure
Applicant has further found that pumps having six ?uid
is reached, the slide member 72 will abut plug 88 and
pressure chambers alternately connects four and then two
of its chambers to the pump discharge to produce large
the port plate 36 will be rotated to its “no ?ow” produc
pressure ?uctuations in the forces tending to separate
ing position for the pump. As the discharge pressure of
'
the pump falls below 1,650 p.s.i. the reverse operation is 75 its valving surfaces.
3,078,808
11
It will be apparent that the objects heretofore enum
erated as well as others have been achieved; and that
an improved pressure balancing arrangement for a single
12
a coaxially positioned recess therein facing said abut
ment surface; a balance ring sealingly engaging the sides
of said recess and having a surface which slidingly en
balancing piston has been provided for ?uid devices hav
gages said abutment surface and having two annular
ing end valving surfaces which are biased apart by pres
sure ?uid between the valving surfaces.
While the invention has been described in considerable
grooves therein de?ning a surface area therebetween pro
surface; a balance ring sealingly engaging the sides of
member having respective valving surfaces which are in
sliding sealing engagement with each other and which
de?ne areas of high and low pressure that are exerted
against said end of said internal member; said internal
portioned to be of less area than its opposite face which
is exposed to pump pressure; a plurality of individual
detail, I do not wish to be limited to the particular con
?ow passages located at a radial distance inwardly of
stmctions shown and described; and it is my intention to
the outer periphery of the wall structure de?ning said re
cover hereby all novel adaptations, modi?cations and ar 10 cess and communicating respective cylinder bores with
rangements thereof which come within the practice of
said recess; said individual ?ow passages each having a
those skilled in the art to which the invention relates.
flow‘ restriction of sector shaped cross-section and of sub
I claim:
stantial length to extend between the opposite faces of
1. In a positive displacement ?uid handling device: an
said balance ring for effecting laminar flow therethrough
outer casing member having ?rst and second opposite 15 from said recess to its respective cylinder bore when its
end walls forming an internal chamber therein and
cylinder bore is communicated to low pressure; and a
through which end walls an axis of rotation extends; an
flow passage in said balance ring communicating the
internal member in said chamber; means for providing
pressure of said recess to the area between said grooves
relative rotation between said internal member and said
to relieve pressure between the sliding engaging surfaces
casing member; said internal member having a plurality‘ 20 of said balance ring and abutment surface.
of cylinder bores therein; a piston in each cylinder bore
3. In a positive displacement ?uid handling device: an
constructed and arranged to be reciprocated in said bore
outer casing member having ?rst and second opposite
during relative rotation of said internal and outer casing
end walls forming an internal chamber therein and
members; said ?rst end wall of said casing member and
through which end walls an axis of rotation extends; an
25
the adjacent end of said internal member having respec
internal member in said chamber; an axially extending
tive valving surfaces which are in sliding sealing engage
shaft extending through said second end wall of said cas
ment with each other and which de?ne areas of high
ing member into said internal chamber for supporting said
and low pressure that are exerted against said end of said
internal member relative to said casing member; means
internal member; said internal member having a ?ow
for providing relative rotation between said internal mem
communicating port for each cylinder bore extending be
ber and said casing member about said shaft; said internal
tween each bore and the valving surface of said internal
member having a plurality of cylinder bores therein; a
member; said second end wall of said casing member
piston in each cylinder bore constructed and arranged to
having a coaxially positioned abutment vsurface facing
be reciprocated in said bore during relative rotation of
said internal member; said internal member having a co
said internal and outer casing members; said first end wall
35
axially positioned recess therein facing said abutment
of said casing member and the adjacent end of said internal
said recess and having a surface with annulm grooves
slidingly engaging said abutment surface, the area, of
said balance ring disposed between said grooves being
communicated by through passages with the opposite face
of said balance ring and proportioned of slightly less area
than the area of said balance ring exposed to the pressure
at its opposite face to effect slight engagement force
between said balance ring and abutment surface; a plu
rality of individual ?ow passages communicating respec
tive cylinder bores with said recess; said individual flow
passages each having a flow restriction de?ned by a sector
shaped cross-section and an elongated length located at
a radial distance inwardly of the outer periphery of the
wall structure de?ning said recess for limiting ?ow there
through from said recess to its respective cylinder bore
when its cylinder bore is communicated to low pressure
to provide laminar ?ow at all times therethrough.
2. In a positive displacement fluid handling device: an
outer casing member having ?rst and second opposite end
walls forming an internal chamber therein and through
which end walls an axis of rotation extends; an internal
member in said chahber; means for providing relative
rotation between said internal member and said casing
member; said internal member having a plurality of cylin
der bores therein; a piston in each cylinder bore con
structed and arranged to be reciprocated in said bore
during relative rotation of said internal and outer casing
members; said ?rst end wall of said casing member and
' member having a ?ow communicating port for each
cylinder bore extending between the radially inner end of
each bore and the valving surface of said internal member;
said second end wall of said casing member having an
45 annular abutment surface surrounding said shaft and
facing said internal member; said internal member having
an annular recess therein surrounding said shaft and
facing said abutment surface; an annular balance ring
sealingly engaging the sides of said recess and having a
surface with annular grooves which slidingly sealingly
engages said abutment surface and having passages ex
tending therethrough to communicate the area between
the annular grooves with the opposite face of said balance
ring whereby pressure from said recess will be com
55 municated to said area between the annular grooves; and
a plurality of individual ?ow passages in said internal
member communicating respective cylinder bores with
said annular recess; said individual ?ow passages each
having a full restriction having a cross section area and
60 length of ?ow path relationship for effecting laminar flow
at all times therein and for limiting ?ow therethrough
from said recess to its respective cylinder bore when its
cylinder bore is communicated to low pressure.
4. In a positive displacement ?uid handling device: an
65 outer casing member having ?rst and second opposite end
the adjacent end of said internal member having respec
walls forming an internal chamber therein and through
tive valving surfaces which are in sliding sealing engage
which end walls an axis of rotation extends; an internal
ment with each other and which de?ne areas of high and
member in said chamber; an ‘axially extending shaft ex
low pressure that are exerted against said end of
tending through said second end wall of said casing mem
said internal member; said internal member having a 70 ber into said internal chamber for supporting said internal
flow communicating port for each cylinder bore extending
member relative to said casing member; means for pro
between each bore and the valving surface of said in
viding relative rotation between said internal member and
ternal member; said second end wall of said casing mem
said casing member about said shaft; said internal member
ber having a coaxially positioned abutment surface fac
having a plurality of cylinder bores therein; a piston in
ing said internal member; said internal member having
each cylinder bore constructed and arranged to be recip~
3,078,808
13
rocated in said bore during relative rotation of said
internal and outer casing members; said ?rst end wall of
said casing member and the adjacent end of said internal
member having respective valving surfaces which are in
sliding sealing engagement with each other and which
14
against said end of said internal member; said internal
member having a ?ow communicating port for each cylin
der bore extending between the radially inner end of each
bore and the valving surface of said internal member; said
second end wall of said casing member having an annular
de?ne areas of high and low pressure that are exerted
abutment surface surrounding said shaft and facing said
against said end of said internal member; said internal
member having a flow communicating port for each cylin
der bore extending between the radially inner end of each
bore and the valving surface of said internal member; 10
internal member; said internal member having an an
nular recess therein surrounding said shaft and facing
said second end wall of said casing member having an
annular abutment surface surrounding said shaft and fac
ing said internal member; said internal member having an
annular recess therein surrounding said shaft and facing
said abutment surface; an annular balance ring sealingly
engaging the sides of said recess and having a surface with
annular grooves which slidingly engages said abutment
surface and having passages extending therethrough to
communicate the area between the annular grooves with
the opposite face of said balance ring whereby the pres
said abutment surface; an annular balance ring sealingly 15 sure from said recess will be communicated to said area be_
engaging the sides of said recess and having a surface with
annular grooves which slidingly engages said abutment
surface and having passages extending therethrough to
communicate the area between the annular grooves with
the opposite face of said balance ring whereby pressure
from said recess will be communicated to said area be
tween the annular grooves; and a plurality of individual
?ow passages in said internal member communicating re
spective cylinder bores with said annular recess; said
tween the annular grooves; and a plurality of individual
openings in said internal member communicating respec
tive cylinder bores with said annular recess; each said
individual opening having a plug ?rmly ?t therein, said
plug being of the same length as said opening and of less
cross section area than said opening thereby forming
a flow passage between said plug and opening, said ?ow
passage having a cross section area and length of ?ow
path relationship for effecting laminar flow at all times
how passages being located at a radial distance inwardly 25 therein and for limiting ?ow therethrough from said
recess to its respective cylinder bore when its cylinder
of the outer periphery of the wall structure de?ning said
bore is communicated to low pressure.
recess; said individual ?ow passages each having a flow
restriction having a cross section area and length of flow
References Cited in the tile of this patent
path relationship for e?ecting laminar ?ow at all times
therein and for limiting ?ow therethrough from said 30
UNITED STATES PATENTS
recess to its respective cylinder bore when its cylinder
Re. 20,026
Thoma ______________ __June 30, 1936
bore is communicated to low pressure.
5. in a positive displacement ?uid handling device: an
outer casing member having ?rst and second opposite end
walls forming an internal chamber therein and through 35
which end walls an axis of rotation extends; an internal
member in said chamber; an axially extending shaft ex
tending through said second end wall of said casing
member into said internal chamber for supporting said
internal member relative to said casing member; means
for providing relative rotation between said internal mem
ber and said casing member about said shaft; said internal
member having a plurality of cylinder bores therein; a pis
ton in each cylinder bore constructed and arranged to be
reciprocated in said bore during relative rotation of said
internal and outer casing members; said ?rst end wall of
said casing member and the adjacent end of said internal
member having respective valving surfaces which are
in sliding sealing engagement with each other and which
de?ne areas of high and low pressure that are exerted 50
669,193
2,111,657
2,155,455
2,257,724
2,393,773
2,698,585
2,741,993
2,895,426
2,972,961
Alexander ____________ __ Mar. 5, 1901
Benedek _____________ __ Mar. 22, 1938
Thoma ______________ __ Apr. 25,
Bennetch _____________ __ Oct. 7,
Hoffer _______________ __ Ian. 29,
Cotner et al. ___________ __ Jan. 4,
Orshansky __________ __ Apr. 17,
‘Orshansky ____________ __ July 21,
Clark _______________ __ Feb. 28,
1939
1941
1946
1955
1956
1959
1961
FOREIGN PATENTS
1,122,271
1,132,654
2,784
France ______________ __ May 22, 1956
France _______________ __ Nov. 5, 1956
Great Britain __________ __ Feb. 3, 1913
678,917
801,678
Great Britain ________ _.. Sept. 10, 1952
Great Britain ________ __ Sept. 17, 1958
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