U.S. patent application number 15/609926 was filed with the patent office on 2018-12-06 for dual output variable displacement axial piston pump and method thereof.
This patent application is currently assigned to Schaeffler Technologies AG & Co. KG. The applicant listed for this patent is Schaeffler Technologies AG & Co. KG. Invention is credited to Joseph Johnson, Jonathan Richards.
Application Number | 20180347552 15/609926 |
Document ID | / |
Family ID | 64279072 |
Filed Date | 2018-12-06 |
United States Patent
Application |
20180347552 |
Kind Code |
A1 |
Johnson; Joseph ; et
al. |
December 6, 2018 |
DUAL OUTPUT VARIABLE DISPLACEMENT AXIAL PISTON PUMP AND METHOD
THEREOF
Abstract
A variable displacement axial pump, including: a housing
including first and second inlet ports and first and second outlet
ports; a shaft arranged to receive rotational torque; an axis of
rotation for the shaft; swash plate located in the housing; a first
cylinder block located in the housing and including first and
second through-bores and first and second pistons at least partly
disposed in the first and second through-bores, respectively, and
connected to the swash plate; and a second cylinder block located
in the housing and including third and fourth through-bores and
third and fourth pistons at least partly disposed in the third and
fourth through-bores, respectively, and connected to the swash
plate. The shaft is arranged to rotate, with respect to the swash
plate, the first and second cylinder blocks about the axis of
rotation.
Inventors: |
Johnson; Joseph;
(Mooresville, NC) ; Richards; Jonathan; (Waxhaw,
NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies AG & Co. KG |
Herzogenaurach |
|
DE |
|
|
Assignee: |
Schaeffler Technologies AG &
Co. KG
Herzogenaurach
DE
|
Family ID: |
64279072 |
Appl. No.: |
15/609926 |
Filed: |
May 31, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04B 19/22 20130101;
F04B 1/324 20130101; F04B 1/2085 20130101; F04B 1/22 20130101 |
International
Class: |
F04B 1/32 20060101
F04B001/32; F04B 1/22 20060101 F04B001/22; F04B 19/22 20060101
F04B019/22 |
Claims
1. A variable displacement axial pump, comprising: a housing
including: first and second inlet ports; and, first and second
outlet ports; a shaft arranged to receive rotational torque; an
axis of rotation for the shaft; a swash plate located in the
housing; a first cylinder block located in the housing and
including: first and second through-bores; and, first and second
pistons at least partly disposed in the first and second
through-bores, respectively, and connected to the swash plate; and,
a second cylinder block located in the housing and including: third
and fourth through-bores; and, third and fourth pistons at least
partly disposed in the third and fourth through-bores,
respectively, and connected to the swash plate, wherein the shaft
is arranged to rotate, with respect to the swash plate, the first
and second cylinder blocks about the axis of rotation.
2. The variable displacement axial pump of claim 1, wherein: the
first and second pistons are arranged to: draw first fluid, via the
first inlet port, into the first and second through-bores,
respectively; and, expel the first fluid from the first and second
through-bores, respectively, into the first outlet port; and, the
third and fourth pistons are arranged to: draw second fluid, via
the second inlet port, into the third and fourth through-bores,
respectively; and, expel the second fluid from the third and fourth
through-bores, respectively, into the second outlet port.
3. The variable displacement axial pump of claim 2, further
comprising: an actuator arranged to pivot the swash plate about an
axis transverse to the axis of rotation, wherein in a first
circumferential position of the swash plate, with respect to the
axis, and at a constant rotational speed for the shaft: the first
cylinder block is arranged to expel the first fluid into the first
outlet port at a first flow rate; the second cylinder block is
arranged to expel the second fluid into the second outlet port at a
second flow rate; and, the first and second flow rates are
equal.
4. The variable displacement axial pump of claim 3, wherein in a
second circumferential position of the swash plate, different from
the first circumferential position of the swash plate, with respect
to the axis, and at the constant rotational speed for the shaft:
the first cylinder block is arranged to expel the first fluid into
the first outlet port at a third flow rate different from the first
flow rate; and, the second cylinder block is arranged to expel the
second fluid into the second outlet port at a fourth flow rate
different from the second flow rate.
5. The variable displacement axial pump of claim 2, further
comprising: an actuator arranged to pivot the swash plate about an
axis transverse to the axis of rotation, wherein in a first
circumferential position of the swash plate, with respect to the
axis, and at a constant rotational speed for the shaft: the first
cylinder block is arranged to expel the first fluid into the first
outlet port at a first flow rate; the second cylinder block is
arranged to expel the second fluid into the second outlet port at a
second flow rate; and, the first and second flow rates are not
equal.
6. The variable displacement axial pump of claim 5, wherein in a
second circumferential position of the swash plate, different from
the first circumferential position of the swash plate, with respect
to the axis, and at the constant rotational speed for the shaft:
the first cylinder block is arranged to expel the first fluid into
the first outlet port at a third flow rate different from the first
flow rate; and, the second cylinder block is arranged to expel the
second fluid into the second outlet port at a fourth flow rate
different from the second flow rate.
7. The variable displacement axial pump of claim 1, further
comprising: an actuator arranged to pivot the swash plate about an
axis transverse to the axis of rotation, wherein in a first
circumferential position of the swash plate, with respect to the
axis and with the first, second, third and fourth through-bores
aligned with the first, second, third and fourth ports,
respectively, the swash plate is arranged to simultaneously:
displace the first piston in a first axial direction by a first
distance; displace the second piston in a second axial direction,
opposite the first axial direction, by the first distance; displace
the third piston in the second axial direction by a second
distance; and, displace the fourth piston in the first axial
direction by the second distance.
8. The variable displacement axial pump of claim 7, wherein in a
second circumferential position of the swash plate, with respect to
the axis, different from the first circumferential position of the
swash plate and with the first, second, third and fourth
through-bores aligned with the first, second, third and fourth
ports, respectively, the swash plate is arranged to simultaneously:
displace the first piston in a first axial direction by a third
distance, different from the first distance; displace the second
piston in the second axial direction, by the third distance;
displace the third piston in the second axial direction by a fourth
distance, different from the second distance; and, displace the
fourth piston in the first axial direction by the fourth
distance.
9. The variable displacement axial pump of claim 1, further
comprising: an actuator arranged to pivot the swash plate about an
axis transverse to the axis of rotation, wherein pivoting, with the
actuator, the swash plate in a first circumferential direction
about the axis is arranged to simultaneously: increase
displacement, in a first axial direction, of the first piston
within the first through-bore; increase displacement, in a second
axial direction opposite the first axial direction, of the second
piston in the second through-bore; increase displacement, in the
second axial direction, of the third piston in the third
through-bore; and, increase displacement, in the first axial
direction, of the fourth piston in the fourth through-bore.
10. The variable displacement axial pump of claim 9, wherein
pivoting, with the actuator, the swash plate in a second
circumferential direction, opposite the first circumferential
direction, about the axis is arranged to simultaneously: decrease
displacement, in the first axial direction, of the first piston
within the first through-bore; decrease displacement, in the second
axial direction, of the second piston in the second through-bore;
decrease displacement, in the second axial direction, of the third
piston in the third through-bore; and, decrease displacement, in
the first axial direction, of the fourth piston in the fourth
through-bore.
11. The variable displacement axial pump of claim 1, wherein the
swash plate is an only swash plate for the variable displacement
axial pump.
12. A variable displacement axial pump, comprising: a housing
including: first and second inlet ports; and, first and second
outlet ports; a shaft arranged to receive rotational torque; an
axis of rotation for the shaft; only one swash plate located in the
housing fixed to prevent rotation with respect to the axis of
rotation; a first cylinder block located in the housing,
non-rotatably connected to the shaft, and including: first and
second through-bores; and, first and second pistons at least partly
disposed in the first and second through-bores, respectively, and
connected to the swash plate; a second cylinder block located in
the housing, non-rotatably connected to the shaft, and including:
third and fourth through-bores; and, third and fourth pistons at
least partly disposed in the third and fourth through-bores,
respectively, and connected to the swash plate; and, an actuator
arranged to rotate the swash plate about an axis transverse to the
axis of rotation, wherein: the shaft is arranged to rotate the
first and second cylinder blocks; the first cylinder block is
arranged to expel first fluid from the first outlet port at a first
flow rate; and, the second cylinder block is arranged to expel
second fluid from the second outlet port at a second flow rate.
13. A variable displacement axial pump, comprising: a housing
including: first and second inlet ports; and, first and second
outlet ports; a shaft arranged to receive rotational torque; an
axis of rotation for the shaft; only one swash plate located in the
housing and fixed to prevent rotation with respect to the shaft; a
first cylinder block located in the housing, non-rotatably
connected to the shaft, and including: first and second
through-bores; and, first and second pistons at least partly
disposed in the first and second through-bores, respectively, and
connected to the swash plate; a second cylinder block located in
the housing, non-rotatably connected to the shaft, and including:
third and fourth through-bores; and, third and fourth pistons at
least partly disposed in the third and fourth through-bores,
respectively, and connected to the swash plate; and, an actuator
arranged to rotate the swash plate about an axis transverse to the
axis of rotation, wherein for rotation of the shaft about the axis
of rotation the swash plate is arranged to displace: the first
piston to draw first fluid into the first through-bore via the
first inlet port; the second piston to expel second fluid from the
second through-bore into the first outlet port; the third piston to
draw third fluid into the third through-bore via the second inlet
port; and, the fourth piston to expel fourth fluid from the fourth
through-bore into the second outlet port.
14. A method of using the variable displacement axial pump of claim
1, comprising: rotating the shaft about the axis of rotation;
rotating, with the shaft, the first and second cylinder blocks
about the axis of rotation and with respect to the swash plate;
axially displacing, with the swash plate, the first, second, third
and fourth pistons; drawing first fluid, via the first inlet port
and using the first and second pistons, into the first and second
through-bores, respectively; expelling, using the first and second
pistons, the first fluid from the first and second through-bores,
respectively, into the first outlet port; drawing second fluid, via
the second inlet port and using the third and fourth pistons, into
the third and fourth through-bores, respectively; and, expelling,
using the third and fourth pistons, the second fluid from the third
and fourth through-bores, respectively, into the second outlet
port.
15. The method of claim 14, further comprising: aligning, in a
first axial direction, the first, second, third and fourth
through-bores with the first inlet port, the first outlet port, the
second inlet port and the second outlet port, respectively; and,
simultaneously displacing, with the swash plate: the first piston a
first distance, in the first axial direction, within the first
through-bore; the second piston the first distance, in a second
axial direction opposite the first axial direction, within the
second through-bore; the third piston a second distance, in the
second axial direction, within the third through-bore; and, the
fourth piston the second distance, in the first axial direction,
within the fourth through-bore.
16. The method of claim 15, further comprising: pivoting, using the
actuator, the swash plate about the axis; aligning, in the first
axial direction, the first, second, third and fourth through-bores
with the first inlet port, the first outlet port, the second inlet
port and the second outlet port, respectively; and, simultaneously
displacing, with the swash plate: the first piston a third
distance, in the first axial direction, within the first
through-bore; the second piston the third distance, in the second
axial direction, within the second through-bore; the third piston a
fourth distance, in the second axial direction, within the third
through-bore; and, the fourth piston the fourth distance, in the
first axial direction, within the fourth through-bore, wherein: the
third distance is different from the first distance; and, the
fourth distance is different from the second distance.
17. A method of using the variable displacement axial pump of claim
12, comprising: rotating the shaft about the axis of rotation at a
constant speed; rotating, with the shaft, the first and second
cylinder blocks about the axis of rotation; and, for a constant
speed of rotation of the shaft: displacing, with the swash plate,
the first and second pistons; drawing first fluid, with the first
and second pistons and from the first inlet port, into the first
cylinder block; expelling, with the first and second pistons and
from the first cylinder block, the first fluid into the first
outlet port at a first flow rate; displacing, with the swash plate,
the third and fourth pistons; drawing second fluid, with the third
and fourth pistons and from the second inlet port, into the second
cylinder block; and, expelling, with the third and fourth pistons
and from the second cylinder block, the second fluid into the
second outlet port at a second flow rate.
18. The method of claim 17, further comprising: pivoting, using the
actuator, the swash plate in a first circumferential direction with
respect to the axis; and, for the constant speed of rotation of the
shaft: displacing, with the swash plate, the first and second
pistons; drawing the first fluid, with the first and second pistons
and from the first inlet port, into the first cylinder block;
expelling, with the first and second pistons and from the first
cylinder block, the first fluid into the first outlet port at a
third flow rate, less than the first flow rate; displacing, with
the swash plate, the third and fourth pistons; drawing the second
fluid, with the third and fourth pistons and from the second inlet
port, into the second cylinder block; and, expelling, with the
third and fourth pistons and from the second cylinder block, the
second fluid into the second outlet port at a fourth flow rate,
less than the second flow rate.
19. The method of claim 18, further comprising: pivoting, using the
actuator, the swash plate in a second circumferential direction,
opposite the first circumferential direction; and, for the constant
speed of rotation of the shaft: displacing, with the swash plate,
the first and second pistons; drawing the first fluid, with the
first and second pistons and from the first inlet port, into the
first cylinder block; expelling, with the first and second pistons
and from the first cylinder block, the first fluid into the first
outlet port at a fifth flow rate, greater than the third flow rate;
displacing, with the swash plate, the third and fourth pistons;
drawing the second fluid, with the third and fourth pistons and
from the second inlet port, into the second cylinder block; and,
expelling, with the third and fourth pistons and from the second
cylinder block, the second fluid into the second outlet port at a
sixth flow rate, greater than the fourth flow rate.
20. A method of using the variable displacement axial pump of claim
13, comprising: rotating the shaft about the axis of rotation; and,
rotating, with the shaft, the first and second cylinder blocks
about the axis of rotation; displacing, with the swash plate, the
first, second, third and fourth pistons; and, simultaneously:
drawing, with the first piston, first fluid into the first
through-bore via the first inlet port; expelling, with the second
piston, second fluid from the second through-bore into the first
outlet port; drawing, with the third piston, third fluid into the
third through-bore via the first inlet port; and, expelling, with
the fourth piston, fourth fluid from the fourth through-bore into
the second outlet port.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a dual output variable
displacement axial piston pump.
BACKGROUND
[0002] Known variable displacement axial piston pumps are limited
to a single output.
SUMMARY
[0003] According to aspects illustrated herein, there is provided a
variable displacement axial pump, including: a housing including
first and second inlet ports and first and second outlet ports; a
shaft arranged to receive rotational torque; an axis of rotation
for the shaft; a plate located in the housing; a first cylinder
block located in the housing and including first and second
through-bores and first and second pistons at least partly disposed
in the first and second through-bores, respectively, and connected
to the swash plate; and a second cylinder block located in the
housing and including third and fourth through-bores and third and
fourth pistons at least partly disposed in the third and fourth
through-bores, respectively, and connected to the swash plate. The
shaft is arranged to rotate, with respect to the swash plate, the
first and second cylinder blocks about the axis of rotation.
[0004] According to aspects illustrated herein, there is provided a
variable displacement axial pump, including: a housing including
first and second inlet ports and first and second outlet ports; a
shaft arranged to receive rotational torque; an axis of rotation
for the shaft; a swash plate located in the housing fixed to
prevent rotation with respect to the axis of rotation; a first
cylinder block located in the housing, non-rotatably connected to
the shaft, and including first and second through-bores and first
and second pistons at least partly disposed in the first and second
through-bores, respectively, and connected to the swash plate; a
second cylinder block located in the housing, non-rotatably
connected to the shaft, and including third and fourth
through-bores and third and fourth pistons at least partly disposed
in the third and fourth through-bores, respectively, and connected
to the swash plate; and an actuator arranged to rotate the swash
plate about an axis transverse to the axis of rotation. The shaft
is arranged to rotate the first and second cylinder blocks. The
first cylinder block is arranged to expel first fluid from the
first outlet port at a first flow rate. The second cylinder block
is arranged to expel second fluid from the second outlet port at a
second flow rate.
[0005] According to aspects illustrated herein, there is provided a
variable displacement axial pump, including: a housing including
first and second inlet ports and first and second outlet ports; a
shaft arranged to receive rotational torque; an axis of rotation
for the shaft; a swash plate located in the housing and fixed to
prevent rotation with respect to the shaft; a first cylinder block
located in the housing, non-rotatably connected to the shaft, and
including first and second through-bores and first and second
pistons at least partly disposed in the first and second
through-bores, respectively, and connected to the swash plate; a
second cylinder block located in the housing, non-rotatably
connected to the shaft, and including third and fourth
through-bores; and third and fourth pistons at least partly
disposed in the third and fourth through-bores, respectively, and
connected to the swash plate; and an actuator arranged to rotate
the swash plate about an axis transverse to the axis of rotation.
For rotation of the shaft about the axis of rotation the swash
plate is arranged to displace: the first piston to draw first fluid
into the first through-bore via the first inlet port; the second
piston to expel second fluid from the second through-bore into the
first outlet port; the third piston to draw third fluid into the
third through-bore via the second inlet port; and the fourth piston
to expel fourth fluid from the fourth through-bore into the second
outlet port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Various embodiments are disclosed, by way of example only,
with reference to the accompanying schematic drawings in which
corresponding reference symbols indicate corresponding parts, in
which:
[0007] FIG. 1 is a schematic cross-sectional representation of a
dual output variable displacement axial piston pump with a rotating
swash plate in a first position;
[0008] FIG. 2 is schematic cross-sectional representation of the
dual output variable displacement axial piston pump in FIG. 1 with
cylinder blocks rotated approximately 180 degrees about an axis of
rotation;
[0009] FIG. 3 is a schematic cross-sectional representation of the
dual output variable displacement axial piston pump in FIG. 1 with
the rotating swash plate in a second position; and
[0010] FIG. 4 is a perspective view of a cylindrical coordinate
system demonstrating spatial terminology used in the present
application.
DETAILED DESCRIPTION
[0011] At the outset, it should be appreciated that like drawing
numbers on different drawing views identify identical, or
functionally similar, structural elements of the disclosure. It is
to be understood that the disclosure as claimed is not limited to
the disclosed aspects.
[0012] Furthermore, it is understood that this disclosure is not
limited to the particular methodology, materials and modifications
described and as such may, of course, vary. It is also understood
that the terminology used herein is for the purpose of describing
particular aspects only, and is not intended to limit the scope of
the present disclosure.
[0013] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which this disclosure belongs. It
should be understood that any methods, devices or materials similar
or equivalent to those described herein can be used in the practice
or testing of the disclosure.
[0014] FIG. 4 is a perspective view of cylindrical coordinate
system 10 demonstrating spatial terminology used in the present
application. The present application is at least partially
described within the context of a cylindrical coordinate system.
System 10 includes axis of rotation, or longitudinal axis, 11, used
as the reference for the directional and spatial terms that follow.
Opposite axial directions AD1 and AD2 are parallel to axis 11.
Radial direction RD1 is orthogonal to axis 11 and away from axis
11. Radial direction RD2 is orthogonal to axis 11 and toward axis
11. Opposite circumferential directions CD1 and CD2 are defined by
an endpoint of a particular radius R (orthogonal to axis 11)
rotated about axis 11, for example clockwise and counterclockwise,
respectively.
[0015] To clarify the spatial terminology, objects 12, 13, and 14
are used. As an example, an axial surface, such as surface 15A of
object 12, is formed by a plane co-planar with axis 11. However,
any planar surface parallel to axis 11 is an axial surface. For
example, surface 15B, parallel to axis 11 also is an axial surface.
An axial edge is formed by an edge, such as edge 15C, parallel to
axis 11. A radial surface, such as surface 16A of object 13, is
formed by a plane orthogonal to axis 11 and co-planar with a
radius, for example, radius 17A. A radial edge is co-linear with a
radius of axis 11. For example, edge 16B is co-linear with radius
17B. Surface 18 of object 14 forms a circumferential, or
cylindrical, surface. For example, circumference 19, defined by
radius 20, passes through surface 18.
[0016] Axial movement is in direction axial direction AD1 or AD2.
Radial movement is in radial direction RD1 or RD2. Circumferential,
or rotational, movement is in circumferential direction CD1 or CD2.
The adverbs "axially," "radially," and "circumferentially" refer to
movement or orientation parallel to axis 11, orthogonal to axis 11,
and about axis 11, respectively. For example, an axially disposed
surface or edge extends in direction AD1, a radially disposed
surface or edge extends in direction RD1, and a circumferentially
disposed surface or edge extends in direction CD1.
[0017] FIG. 1 is a schematic cross-sectional representation of dual
output variable displacement axial piston pump 100 with a rotating
swash plate in a first position. Dual output variable displacement
axial pump 100 includes: housing 102; inlet port 104, outlet port
106, inlet port 108, and outlet port 110 in housing 102; shaft 112;
axis of rotation AR for shaft 112; swash plate 114 located in
housing 102; cylinder blocks 116 and 118 in housing 102; and
actuator 120. In an example embodiment, pump 100 includes only one
swash plate, for example swash plate 114. By "only one swash plate"
we mean that there is no other swash plate in pump 100. In an
example embodiment, actuator arm 121 connects actuator 120 to plate
114. Plate 114 is circumferentially fixed with respect to axis of
rotation AR. That is, plate 114 does not rotate with shaft 112
about axis AR within housing 102. Port 104 is connected to a fluid
reservoir (not shown) providing fluid F1, and port 108 is connected
to a fluid reservoir (not shown) providing fluid F2. Inlet ports
104 and 108 can be connected to separate fluid reservoirs or to a
common reservoir. Actuator 120 is arranged to pivot, rotate or
displace, plate 114 about axis A transverse to axis AR.
[0018] Shaft 112 is arranged to rotate blocks 116 and 118 about
axis AR and with respect to swash plate 114. Block 116 includes
through-bores 122 and 124 and pistons 126 and 128. Pistons 126 and
128 are at least partly disposed in through-bores 122 and 124,
respectively, and are engaged with plate 114. By "engaged with" we
mean that pistons 126 and 128 maintain connection to plate 114
during rotation of block 116 about axis AR. In an example
embodiment, each of pistons 126 and 128 is connected to swash plate
114 via a respective retention assembly 129 as is known in the
art.
[0019] Block 118 includes through-bores 130 and 132 and pistons 134
and 136. Pistons 134 and 136 are at least partly disposed in
through-bores 130 and 132, respectively, and are engaged with plate
114. By "engaged with" we mean that pistons 134 and 136 maintain
connection to plate 114 during rotation of block 118 about axis AR.
In an example embodiment, each of pistons 134 and 136 is connected
to swash plate 114 via a respective retention assembly 129, as is
known in the art.
[0020] For rotation of block 116 about axis AR: pistons 126 and 128
are arranged to draw fluid F1, via port 104, into through-bores 122
and 124, respectively; and expel fluid F1 from through-bores 122
and 124 into port 106 at a flow rate, or pump rate. For rotation of
block 118 about axis AR: pistons 134 and 136 are arranged to draw
fluid F2, via port 108, into through-bores 130 and 132,
respectively; and expel fluid F2 from through-bores 130 and 132
into port 110 at a flow rate, or pump rate. In the example of FIG.
1, the flow rates at ports 106 and 110 are 137A and 137B,
respectively.
[0021] Flow rate 137A is dependent upon the speed of rotation of
block 116 and the displacement of pistons 126 and 128, by plate
114, within through-bores 122 and 124, respectively. The speed of
rotation of block 116 is a function of engine E for a vehicle or
device (not shown) housing pump 100 and is determined by operations
of the vehicle or device other than that for pump 100. That is, the
speed of rotation is not controllable by pump 100. For a given
position of plate 114 about axis A, increasing or decreasing the
speed of rotation of block 116 increases or decreases rate 137A,
respectively.
[0022] Flow rate 137B is dependent upon the speed of rotation of
block 118 and the displacement of pistons 134 and 136, by plate
114, within through-bores 130 and 132, respectively. The speed of
rotation of block 118 is a function of engine E. For a given
position of plate 114 about axis A, increasing or decreasing the
speed of rotation of block 118 increases or decreases rate 137B,
respectively.
[0023] FIG. 2 is a schematic cross-sectional representation of dual
port variable displacement axial piston pump 100 in FIG. 1 with
cylinder blocks 116 and 118 rotated approximately 180 degrees about
axis of rotation AR. In the example of FIG. 2, as a result of the
rotation of blocks 116 and 118 180 degrees about axis AR:
through-bores 122, 124, 130, and 132 are aligned, in direction AD1,
with ports 106, 104, 110, and 108, respectively. Plate 114 has
simultaneously:
[0024] 1. Displaced piston 126 in axial direction AD2, within
through-bore 122.
[0025] 2. Displaced piston 128 in axial direction AD1 within
through-bore 124.
[0026] 3. Displaced piston 134 in axial direction AD1, within
through-bore 130.
[0027] 4. Displaced piston 136 in axial direction AD2 within
through-bore 132.
[0028] As a result of the rotation of blocks 116 and 118 in FIG. 2:
fluid F1 in through-bore 122 (drawn into through-bore 122 in FIG.
1) is expelled into port 106 by displacement of piston 126 in
direction AD2; fluid F1 is drawn into through-bore 124 due to
suction produced by displacement of piston 128 in direction AD1;
fluid F2 in through-bore 130 (drawn into through-bore 130 in FIG.
1) is expelled into port 110 by displacement of piston 134 in
direction AD1; and fluid F2 is drawn into through-bore 132 by
suction produced by displacement of piston 136 in direction
AD2.
[0029] The continued rotation of blocks 116 and 118 about axis AR
results in a repeating cycle of: drawing fluid F1 from port 104
into through-bores 122 and 124, and expelling fluid F1 from
through-bores 122 and 124 into port 106; and, drawing fluid F2 from
port 108 into through-bores 130 and 132, and expelling fluid F2
from through-bores 130 and 132 into port 110. The preceding cycle
is applicable to any rotational speed of shaft 112 and any
circumferential position of plate 114 with respect to axis A. With
the configuration of ports 104, 106, 108 and 110 shown in FIG. 1,
angle 139 between plate 114 and axis AR is acute (less than 90
degrees). For a configuration (not shown) in which the respective
positions of ports 104 and 106 are switched and the respective
positions of ports 108 and 110 are switched, angle 139 between
plate 114 and axis AR is obtuse (greater than 90 degrees).
[0030] Flow rates 137A and 137B are governed by the circumferential
position of plate 114 with respect to axis A. The circumferential
position of plate 114 determines the distance that pistons 126,
128, 134, and 136 are displaced by plate 114 within through-bores
122, 124, 130, and 132, respectively. As seen in the example of
FIGS. 1 and 2: piston 126 displaces distance 138 in direction AD2
in the transition from FIG. 1 to FIG. 2; and piston 128 displaces
distance 138 in direction AD1 in the transition from FIG. 2 to FIG.
1. Thus, pistons 126 and 128 displace distance 138 to draw fluid F1
into through-bores 122 and 124, respectively, and pistons 126 and
128 displace distance 138 to expel fluid F1 from through-bores 122
and 124, respectively.
[0031] As discussed below, changing the extent of the axial
displacement of pistons 126 and 128 (for example, distance 138)
changes the amount of fluid F1 drawn into and expelled by block 116
and hence changes flow rate 137A.
[0032] As seen in the example of FIGS. 1 and 2: piston 134
displaces distance 140 in direction AD1 in the transition from FIG.
1 to FIG. 2; and piston 136 displaces distance 140 in direction AD2
in the transition from FIG. 2 to FIG. 1. Thus, pistons 134 and 136
displace distance 140 to draw fluid F2 into through-bores 130 and
132, respectively, and pistons 134 and 136 displace distance 140 to
expel fluid F2 from through-bores 130 and 132, respectively.
[0033] As discussed below, changing the extent of the axial
displacement of pistons 134 and 136 (for example, distance 140)
changes the amount of fluid F2 drawn into and expelled by block 118
and hence changes flow rate 137B.
[0034] FIG. 3 is a schematic cross-sectional representation of dual
output variable displacement axial piston pump 100 in FIG. 1 with
rotating swash plate 114 in a second circumferential position. In
the example of FIG. 3, swash plate 114 has been rotated, by
actuator 120, in direction CD1 about axis A from the position shown
in FIG. 1. The alignment of through-bores 122, 124, 130, and 132
with ports 104, 106, 108, and 110 remains the same. The rotation
and subsequent tilting of swash plate 114 in FIG. 3 changes the
axial displacement of pistons 126, 128, 134, and 136. As a result:
pistons 126 and 128 are displaced distance 142 by plate 114; and
pistons 134 and 136 are displaced distance 144 by plate 114. In the
example of FIGS. 1 through 3: distance 142 is less than distance
138; and distance 144 is less than distance 140.
[0035] Assuming a constant speed of rotation of shaft 112 in FIGS.
1 through 3, and since distance 142 is less than distance 138, the
amount of fluid F1 drawn into and expelled from through-bores 122
and 124 in FIG. 3 (flow rate 137C) decreases in comparison to the
amount of fluid F1 drawn into through-bores 122 and 124 in FIGS. 1
and 2. Assuming the constant speed of rotation of shaft 112 in
FIGS. 1 through 3, and since distance 144 is less than distance
140, the amount of fluid F2 drawn into and expelled from
through-bores 130 and 132 in FIG. 3 (flow rate 137D) decreases in
comparison to the amount of fluid F2 drawn into through-bores 130
and 132 in FIGS. 1 and 2. Thus rates 137C and 137D in FIG. 3 are
less than rates 137A and 137B, respectively, in FIGS. 1 and 2.
[0036] The following discussion is directed to a transition from
FIG. 3 to FIG. 1. To transition from FIG. 3 to FIG. 1, swash plate
114 is pivoted, by actuator 120, about axis A in direction CD1.
Assuming the constant speed of rotation of shaft 112 in FIGS. 1
through 3, and since distance 142 is less than distance 138, the
amount of fluid F1 drawn into and expelled from through-bores 122
and 124 in FIG. 1 increases in comparison to the amount of fluid F1
drawn into through-bores 122 and 124 in FIG. 3. Assuming the
constant speed of rotation of shaft 112 in FIGS. 1 through 3, and
since distance 144 is less than distance 140, the amount of fluid
F2 drawn into and expelled from through-bores 130 and 132 in FIG. 1
increases in comparison to the amount of fluid F2 drawn into and
expelled from through-bores 130 and 132 in FIG. 3. Thus rates 137A
and 137B in FIGS. 1 and 2 are greater than rates 137C and 137D,
respectively, in FIG. 3.
[0037] The following should be viewed in light of FIGS. 1 through
3. The following describes a method using variable displacement
axial pump 100. A first step positions, using actuator 120, swash
plate 114 in a first circumferential position with respect to axis
A. A second step rotates, with engine E, shaft 112 about axis AR. A
third step rotates cylinder blocks 116 and 118 about axis AR and
with respect to swash plate 114. A fourth step axially displaces,
with plate 114, pistons 126, 128, 134 and 136. A fifth step draws
fluid F1, via inlet port 104 and using pistons 126 and 128, into
through-bores 122 and 124, respectively. A sixth step expels, using
pistons 126 and 128, fluid F1 from through-bores 122 and 124,
respectively, into outlet port 106. A seventh step draws fluid F2,
via inlet port 108 and using pistons 134 and 136, into
through-bores 130 and 132, respectively. An eighth step expels,
using pistons 134 and 136, fluid F2 from through-bores 130 and 132,
respectively, into outlet port 110.
[0038] A ninth step aligns, in axial direction AD1, through-bores
122, 124, 130 and 132 with port 104, port 106, port 108 and port
110, respectively. Axially displacing, with plate 114, pistons 126,
128, 134 and 136 includes simultaneously displacing, with swash
plate 114: piston 126 distance 138, in axial direction AD1, within
through-bore 122; piston 128 distance 138, in axial direction AD2,
within through-bore 124; piston 134 distance 140, in axial
direction AD2, within through-bore 130; and piston 136 distance
140, in axial direction AD1, within through-bore 132.
[0039] A tenth step pivots, with actuator 120, plate 114 in
direction CD2 about axis A. An eleventh step aligns, in axial
direction AD1, through-bores 122, 124, 130 and 132 with port 104,
port 106, port 108 and port 110, respectively. Axially displacing,
with plate 114, pistons 126, 128, 134 and 136 includes
simultaneously displacing, with swash plate 114: piston 126
distance 142, in axial direction AD1, within through-bore 122;
piston 128 distance 142, in axial direction AD2, within
through-bore 124; piston 134 distance 144, in axial direction AD2,
within through-bore 130; and piston 136 distance 144, in axial
direction AD1, within through-bore 132.
[0040] A twelfth step pivots plate 114 in direction CD1 about axis
A. A thirteenth step aligns, in axial direction AD1, through-bores
122, 124, 130 and 132 with port 104, port 106, port 108 and port
110, respectively. Axially displacing, with plate 114, pistons 126,
128, 134 and 136 includes simultaneously displacing, with swash
plate 114: piston 126 distance 138, in axial direction AD1, within
through-bore 122; piston 128 distance 138, in axial direction AD2,
within through-bore 124; piston 134 distance 140, in axial
direction AD2, within through-bore 130; and piston 136 distance
140, in axial direction AD1, within through-bore 132.
[0041] The following should be viewed in light of FIGS. 1 through
3. The following describes a method using variable displacement
axial pump 100. A first step positions, using actuator 120, swash
plate 114 in a first circumferential position with respect to axis
A. A second step rotates, with engine E, shaft 112 about axis AR. A
third step rotates cylinder blocks 116 and 118 about axis AR and
with respect to swash plate 114. A fourth step, for a constant
speed of rotation of shaft 112: displaces, with swash plate 114,
pistons 126 and 128; draws fluid F1, with pistons 126 and 128 and
from inlet port 104, into cylinder block 116; expels, with pistons
126 and 128 and from cylinder block 116, fluid F1 into outlet port
106 at flow rate 137A; displaces, with swash plate 114, pistons 134
and 136; draws fluid F2, with pistons 134 and 136 and from inlet
port 108, into cylinder block 118; expels, with pistons 134 and 136
and from cylinder block 118, fluid F2 into outlet port 110 at flow
rate 137B.
[0042] A fifth step pivots, using actuator 120, swash plate 114 in
circumferential direction CD1 with respect to axis A; A sixth step,
for the constant speed of rotation of shaft 112: displaces, with
swash plate 114, pistons 126 and 128; draws fluid F1, with pistons
126 and 128 and from inlet port 104, into cylinder block 116;
expels, with pistons 126 and 128 and from cylinder block 116, fluid
F1 into outlet port 106 at flow rate 137C, less than the flow rate
137A; displaces, with swash plate 114, pistons 134 and 136; draws
fluid F2, with pistons 134 and 136 and from inlet port 108, into
cylinder block 118; expels, with pistons 134 and 136 and from
cylinder block 118, fluid F2 into outlet port 110 at flow rate
137D, less than flow rate 137B.
[0043] A seventh step pivots, using actuator 120 and from the first
circumferential position of swash plate 114, swash plate 114 in
circumferential direction CD2. A eighth step, for the constant
speed of rotation of shaft 112: displaces, with swash plate 114,
pistons 126 and 128; draws fluid F1, with pistons 126 and 128 and
from inlet port 104, into cylinder block 116; expels, with pistons
126 and 128 and from cylinder block 116, fluid F1 into outlet port
106 at flow rate 137A, greater than flow rate 137C; displaces, with
swash plate 114, pistons 134 and 136; draws fluid F2, with pistons
134 and 136 and from inlet port 108, into cylinder block 118; and
expels, with pistons 134 and 136 and from cylinder block 118, fluid
F2 into outlet port 110 at flow rate 137B, greater than flow rate
137D.
[0044] The following should be viewed in light of FIGS. 1 through
3. The following describes a method using variable displacement
axial pump 100. A first step rotates shaft 112 about axis AR. A
second step rotates cylinder blocks 116 and 118, about axis AR and
with respect to swash plate 114. A third step simultaneously:
draws, with piston 126, fluid into through-bore 122 via inlet port
104; expels, with piston 128, fluid from through-bore 124 into
outlet port 106; draws, with piston 134, fluid into through-bore
130 via inlet port 108; and expels, with piston 136, fluid from
through-bore 132 into outlet port 110.
[0045] Advantageously, pump 100 simultaneously implements two
pumping operations (for example, fluid F1 through port 104 to port
106, and fluid F2 through port 108 to port 110) using a single
swash plate 114. By using single swash plate 114 and single
actuator 120 to control flow from cylinder blocks 116 and 118, and
hence produce two fluid streams, a second swash plate and actuator,
normally needed to produce two fluid streams, can be eliminated,
reducing the overall space requirement, component count, and cost
requirements for producing two fluid streams.
[0046] It will be appreciated that various of the above-disclosed
and other features and functions, or alternatives thereof, may be
desirably combined into many other different systems or
applications. Various presently unforeseen or unanticipated
alternatives, modifications, variations, or improvements therein
may be subsequently made by those skilled in the art which are also
intended to be encompassed by the following claims.
LIST OF REFERENCE CHARACTERS
[0047] 10 cylindrical system [0048] 11 axis of rotation [0049] AD1
axial direction [0050] AD2 axial direction [0051] RD1 radial
direction [0052] RD2 radial direction [0053] CD1 circumferential
direction about axis AR [0054] CD2 circumferential direction about
axis AR [0055] R radius [0056] 12 object [0057] 13 object [0058] 14
object [0059] 15A surface [0060] 15B surface [0061] 15C edge [0062]
16A surface [0063] 16B edge [0064] 17A radius [0065] 17B radius
[0066] 18 surface [0067] 19 circumference [0068] 20 radius [0069] A
axis transverse to axis AR [0070] AR axis of rotation for shaft 112
[0071] CD1 circumferential direction about axis A [0072] CD2
circumferential direction about axis A [0073] 100 variable
displacement axial pump [0074] 102 housing [0075] 104 inlet port
[0076] 106 inlet port [0077] 108 outlet port [0078] 110 outlet port
[0079] 112 shaft [0080] 114 swash plate [0081] 116 cylinder block
[0082] 118 cylinder block [0083] 120 actuator [0084] 121 actuator
arm [0085] 122 through-bore in block 116 [0086] 124 through-bore in
block 116 [0087] 126 piston in block 116 [0088] 128 piston in block
116 [0089] 129 retention assembly [0090] 130 through-bore in block
118 [0091] 132 through-bore in block 118 [0092] 134 piston in block
118 [0093] 136 piston in block 118 [0094] 137A flow rate for block
116 [0095] 137B flow rate for block 118 [0096] 137C flow rate for
block 116 [0097] 137D flow rate for block 118 [0098] 138
displacement distance for pistons 126 and 128 [0099] 139 acute
angle between shaft 112 and swash plate 114 [0100] 140 displacement
distance for pistons 134 and 136 [0101] 142 displacement distance
for pistons 126 and 128 [0102] 144 displacement distance for
pistons 134 and 136
* * * * *