U.S. patent application number 12/024795 was filed with the patent office on 2009-08-06 for floating cup pump assembly.
This patent application is currently assigned to CATERPILLAR INC.. Invention is credited to Viral S. Mehta, Bryan E. Nelson, Kirat Shah.
Application Number | 20090196768 12/024795 |
Document ID | / |
Family ID | 40931872 |
Filed Date | 2009-08-06 |
United States Patent
Application |
20090196768 |
Kind Code |
A1 |
Nelson; Bryan E. ; et
al. |
August 6, 2009 |
FLOATING CUP PUMP ASSEMBLY
Abstract
A pump assembly with a rotor adapted to rotate around a first
axis and supporting outwardly projecting piston elements includes
at least one drum plate adapted to rotate around a second axis in
angled relation to the first axis. The drum plate supports
outwardly projecting cup elements such that the cup elements
mateably engage distal portions of corresponding piston elements. A
curved surface support element is mounted in sliding relation along
a rotatable shaft structure and operatively engages the drum plate.
A biasing element urges the curved surface support element and drum
plate away from the rotor.
Inventors: |
Nelson; Bryan E.; (Lacon,
IL) ; Mehta; Viral S.; (Peoria, IL) ; Shah;
Kirat; (Dunlap, IL) |
Correspondence
Address: |
LEYDIG, VOIT & MAYER, LTD
TWO PRUDENTIAL PLAZA SUITE 4900, 180 N. STETSON AVE
CHICAGO
IL
60601
US
|
Assignee: |
CATERPILLAR INC.
Peoria
IL
|
Family ID: |
40931872 |
Appl. No.: |
12/024795 |
Filed: |
February 1, 2008 |
Current U.S.
Class: |
417/269 |
Current CPC
Class: |
F04B 1/22 20130101; F04B
1/2007 20130101 |
Class at
Publication: |
417/269 |
International
Class: |
F04B 27/00 20060101
F04B027/00 |
Claims
1. A pump assembly comprising: a rotor supporting a plurality of
piston elements projecting away from said rotor, wherein said rotor
is adapted to rotate around a first axis; a drum plate supporting a
plurality of cup elements, said plurality of cup elements being
adapted to mateably engage distal portions of said piston elements
such that said cup elements circumferentially surround said distal
portions of said piston elements, said drum plate being adapted to
rotate around a second axis in angled relation to said first axis;
a curved surface support element operatively engaging said drum
plate, said curved surface support element being mounted in sliding
relation along a rotatable shaft structure between said rotor and
said drum plate; and at least one biasing element disposed between
said rotor and said curved surface support element urging said
curved surface support element and said drum plate away from said
rotor.
2. The pump assembly as recited in claim 1, wherein said curved
surface support element is non-integral with said rotatable shaft
structure.
3. The pump assembly as recited in claim 2, wherein said curved
surface support element is disposed circumferentially around said
rotatable shaft structure.
4. The pump assembly as recited in claim 3, wherein said curved
surface support element is held in non-rotatable relation relative
to said rotatable shaft structure, such that rotation of said
rotatable shaft structure is translated to said curved surface
support element.
5. The pump assembly as recited in claim 4, wherein said curved
surface support element includes a convex exterior surface
portion.
6. The pump assembly as recited in claim 5, wherein said curved
surface support element further includes at least one detent
projecting radially away from said convex exterior surface portion,
said at least one detent being adapted to operatively engage said
drum plate such that rotation of said rotatable shaft structure is
translated to said drum plate.
7. The pump assembly as recited in claim 6, wherein said at least
one detent is integral with said convex exterior surface
portion.
8. The pump assembly as recited in claim 6, wherein said convex
exterior surface portion operatively engages an angled cheek
portion of said drum plate.
9. The pump assembly as recited in claim 6, wherein said curved
surface support element includes an interior portion adapted to
engage a cooperating splined surface of said rotatable shaft
structure.
10. The pump assembly as recited in claim 9, wherein said interior
portion of said curved surface support element includes a pattern
of grooves, and said cooperating splined surface of said rotatable
shaft structure includes a pattern of ridges adapted to engage said
grooves.
11. The pump assembly as recited in claim 9, wherein said interior
portion of said curved surface support element includes a pattern
of ridges, and said cooperating splined surface of said rotatable
shaft structure includes a pattern of grooves adapted to engage
said ridges.
12. A pump assembly comprising: a rotor supporting a first
plurality of piston elements projecting away from a first side of
said rotor and a second plurality of piston elements projecting
away from a second side of said rotor, wherein said rotor is
adapted to rotate around a first axis; a first drum plate
supporting a first plurality of cup elements, said first plurality
of cup elements being adapted to mated engagement with distal
portions of said first plurality of piston elements such that said
first plurality of cup elements circumferentially surround said
distal portions of said first plurality of piston elements, said
first drum plate being adapted to rotate around a second axis in
angled relation to said first axis; a second drum plate supporting
a second plurality of cup elements, said second plurality of cup
elements being adapted for mated engagement with distal portions of
said second plurality of piston elements such that said second
plurality of cup elements circumferentially surround said distal
portions of said second plurality of piston elements, said second
drum plate being adapted to rotate around a third axis in angled
relation to said first axis; a first curved surface support element
operatively engaging said first drum plate, said first curved
surface support element being mounted in sliding relation along a
first rotatable shaft structure between said rotor and said first
drum plate; a second curved surface support element operatively
engaging said second drum plate, said second curved surface support
element being mounted in sliding relation along a second rotatable
shaft structure between said rotor and said second drum plate; at
least one biasing element disposed between said rotor and said
first curved surface support element urging said first curved
surface support element and said first drum plate away from said
rotor; and at least one biasing element disposed between said rotor
and said second curved surface support element urging said second
curved surface support element and said second drum plate away from
said rotor.
13. The pump assembly as recited in claim 12, wherein said first
curved surface support element is non-integral with said first
rotatable shaft structure and said second curved surface support
element is non-integral with said second rotatable shaft
structure.
14. The pump assembly as recited in claim 13, wherein said first
curved surface support element is disposed circumferentially around
said first rotatable shaft structure and said second curved surface
support element is disposed circumferentially around said second
rotatable shaft structure, said first curved surface support
element being held in non-rotatable relation relative to said first
rotatable shaft structure such that rotation of said first
rotatable shaft structure is translated to said first curved
surface support element, and said second curved surface support
element being held in non-rotatable relation relative to said
second rotatable shaft structure such that rotation of said second
rotatable shaft structure is translated to said second curved
surface support element.
15. The pump assembly as recited in claim 14, wherein said first
curved surface support element includes a first convex exterior
surface portion having at least one detent projecting radially away
from said first convex exterior surface portion, said at least one
detent being integral with said first convex exterior surface
portion and adapted to operatively engage said first drum plate
such that rotation of said first rotatable shaft structure is
translated to said first drum plate, said second curved surface
support element including a second convex exterior surface portion
having at least one detent projecting radially away from said
second convex exterior surface portion, said at least one detent
being integral with said second convex exterior surface portion and
adapted to operatively engage said second drum plate such that
rotation of said second rotatable shaft structure is translated to
said second drum plate.
16. The pump assembly as recited in claim 14, wherein said first
curved surface support element includes a first interior portion
adapted to engage a cooperating splined surface of said first
rotatable shaft structure and wherein said second curved surface
support element includes a second interior portion adapted to
engage a cooperating splined surface of said second rotatable shaft
structure.
17. A method of constructing a pump assembly, the method comprising
the steps of: providing a rotor supporting a plurality of outwardly
projecting piston elements; providing at least one drum plate
supporting a plurality of outwardly projecting cup elements;
orienting said rotor in angled relation relative to said at least
one drum plate such that said cup elements mateably engage distal
portions of corresponding piston elements and said cup elements
circumferentially surround distal portions of said piston elements
and such that said rotor is rotatable around a first axis and said
drum plate is rotatable around a second axis in angled relation to
said first axis; providing a curved surface support element
operatively engaging said at least one drum plate, said curved
surface support element being mounted in sliding relation along a
rotatable shaft structure; and providing at least one biasing
element between said rotor and said curved surface support element
urging said curved surface support element and said at least one
drum plate away from said rotor.
18. The method of constructing a pump assembly as recited in claim
17, wherein said curved surface support element is non-integral
with said rotatable shaft structure.
19. The method of constructing a pump assembly as recited in claim
18, wherein said curved surface support element is mounted
circumferentially around said rotatable shaft structure, said
curved surface support element being held in non-rotatable relation
relative to said rotatable shaft structure such that rotation of
said rotatable shaft structure is translated to said curved surface
support element.
20. The method of constructing a pump assembly as recited in claim
18, wherein said curved surface support element includes an
interior portion engaging a cooperating splined surface of said
rotatable shaft structure.
Description
TECHNICAL FIELD
[0001] This patent disclosure relates generally to pump assemblies
and, more particularly, to floating cup pump assemblies utilizing a
plurality of piston elements disposed around a first rotating
surface and a plurality of complimentary cup elements disposed
around a second rotating surface. The piston elements reciprocate
within the cup elements during rotation.
BACKGROUND
[0002] Pumping devices utilizing a plurality of pistons mounted
around a first rotor and a plurality of complimentary cup elements
mounted around a swash plate in angled relation to the piston rotor
are generally known. One such device is disclosed in United States
Patent Application No. 2006/0222516 in the name of Achten having a
publication date of Oct. 5, 2006. Embodiments of pumps described in
this reference include a rotor having a plurality of pistons
projecting away from both sides of the rotor. These embodiments
further include a pair of cooperating drum plates supporting an
arrangement of cup elements or drum sleeves adapted to house distal
portions of the pistons. The rotor supporting the pistons rotates
around a first axis of rotation. The drum plates rotate in angled
relation to the first axis. The rotor supporting the pistons is
rotated in tandem with the drum plates during operation. Due to the
angle between the rotor and the drum plates, the pistons are caused
to stroke along the length of the corresponding cup elements such
that the volume occupied by the piston elements is alternately
increased and decreased during a rotational cycle. Thus, fluid
introduced into a cup element when the complimentary piston is in a
substantially withdrawn position may be pressurized and expelled as
the piston is pushed inwardly during the rotational cycle.
[0003] The noted reference discloses that the drum plate housing
cup elements rotate around a convex centering surface or ball guide
that is understood to be integral with a drive shaft. The disclosed
pump assembly further incorporates a relatively complex arrangement
to control the position of the drum plate relative to an outboard
faceplate. Specifically, a plurality of springs is held in a
compressed state between a pair of ring structures. One of the ring
structures is supported against the curved support surface at a
position inboard of the cup springs while the other ring structure
is supported against the drum plate at a position outboard of the
cup springs. Because the curved support is held in a fixed position
integral with the drive shaft, the biasing force of the compressed
cup springs is translated across the outboard ring structure to the
drum plate thereby urging the drum plate to an outboard position in
contact with the faceplate. This arrangement is relatively complex
and may be difficult to construct due to the need to hold the cup
springs in compressed relation between the ring structures during
the assembly process. Accordingly, an alternative construction
which provides the desired biasing forces while reducing complexity
is desirable.
[0004] The foregoing background discussion is intended solely to
aid the reader. It is not intended to limit the disclosure, and
thus should not be taken to indicate that any particular element of
a prior system is unsuitable for use within the disclosed examples,
nor is it intended to indicate any element, including solving the
motivating problem, to be essential in implementing the examples
described herein. The full scope of the implementations and
application of the examples described herein are defined by the
appended claims.
SUMMARY
[0005] The disclosure describes, in one aspect, a pump assembly
having a rotor supporting a plurality of outwardly projecting
piston elements. The rotor is adapted to rotate about a first axis.
The pump assembly further includes at least one drum plate
supporting a plurality of outwardly projecting cup elements. The
drum plate is adapted to rotate about a second axis in angled
relation to the first axis. Cup elements supported at the drum
plate are adapted to mateably engage distal portions of
corresponding piston elements such that the cup elements
circumferentially surround such distal portions of the piston
elements. The pump assembly further includes a curved surface
support element operatively engaging the drum plate. The curved
surface support element is mounted in sliding relation along a
rotatable shaft structure. At least one biasing element is disposed
between the rotor and the curved surface support element thereby
urging the curved surface support element and drum plate away from
the rotor.
[0006] In another aspect this disclosure describes a method for
constructing a pump assembly. This method includes providing a
rotor supporting a plurality of outwardly projecting piston
elements and further providing at least one drum plate supporting a
plurality of outwardly projecting cup elements. The rotor and drum
plate are oriented in angled relation such that the rotor is
rotatable around a first axis and the drum plate is rotatable
around a second axis in angled relation to the first axis. A curved
surface support element is provided to operatively engage the drum
plate. The curved surface support element is mounted in sliding
relation along a rotatable shaft structure at least one biasing
element is provided between the rotor and the curved surface port
element such that the curved surface support element and the drum
plate are urged away from the rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a cut-away schematic view illustrating components
of an exemplary floating cup pump assembly;
[0008] FIG. 2 is an exploded schematic assembly view illustrating a
curved surface support element relative to a rotatable shaft
structure; and
[0009] FIG. 3 is a cut-away schematic view illustrating a distal
portion of a piston element at the interior of a cooperating cup
element.
DETAILED DESCRIPTION
[0010] This disclosure relates to a pump assembly incorporating a
rotor supporting a plurality of outwardly projecting piston
elements and at least one complimentary drum plate supporting a
plurality of cup elements adapted to engage portions of
corresponding piston elements. The rotor and drum plate are angled
relative to one another. During a rotational cycle the pistons move
in a reciprocating manner relative to the cup elements. A pressure
biased support element is disposed in separable relation to a
rotatable shaft structure to translate rotational and biasing
forces to the drum plate thereby urging the drum plate away from
the rotor.
[0011] Reference will now be made to the drawings, wherein like
reference numerals designate like elements in the various views.
FIG. 1 illustrates a pump assembly 10 adapted to be mounted within
a housing (not shown). In this exemplary construction, a rotatable
shaft structure 12 extends along a first axis 13. The rotatable
shaft structure 12 is adapted for rotation around axis 13 by use of
a motor or other external power source. The rotatable shaft
structure 12 engages a rotor 14 in the form of a disk or plate
structure. Thus, rotation of rotatable shaft structure 12 is
translated to rotor 14 such that rotor 14 rotates around the same
axis as rotatable shaft structure 12, namely axis 13.
[0012] In the exemplary construction illustrated in FIG. 1, rotor
14 supports an arrangement of piston elements 16 projecting away
from opposing faces of rotor 14. In this regard, it is to be
understood that while piston elements 16 are illustrated as
projecting away from both sides of rotor 14, it is likewise
contemplated that piston elements 16 may be disposed across a
single side of rotor 14 if desired. As shown, piston elements 16
may have a generally frusto-conical configuration such that piston
elements 16 taper outwardly as distance increases away from rotor
14. However, other suitable constructions may likewise be utilized
as desired.
[0013] In the illustrated construction of FIG. 1, pump assembly 10
includes a pair of drum plates 18 disposed on either side of rotor
14. As shown, drum plates 18 support an arrangement of cup elements
20 having acceptance openings projecting towards rotor 14. The cup
elements 20 are arranged to house distal portions of complimentary
piston elements 16. As best illustrated in FIG. 3, cup elements 20
may have a cross-sectional shape and size substantially
corresponding to distal portions of piston elements 16 such that
piston rings 22 provide a substantially fluid tight sealing
relation between piston elements 16 and interior portions of cup
elements 20. In this configuration, cup elements 20
circumferentially surround distal portions of corresponding piston
elements 16 such that piston elements 16 cooperate with interior
boundary walls of cup elements 20 to define a plurality of variable
volume chambers 24. In this regard, it will be understood that
piston rings 22 are optional and may be eliminated if an adequate
sealing relation is obtained directly between the piston elements
16 and cup elements 20. In the exemplary construction illustrated
in FIG. 1, the variable volume chambers 24 are in fluid
communication with inlet ports 30 and outlet ports 32 arranged in
face plates 34 disposed in outboard relation to drum plates 18.
Although the illustrated construction uses a pair of drum plates
18, such a construction is exemplary only. Thus, it is likewise
contemplated that a single drum plate 18 disposed on one side of
rotor 14 may be utilized if desired.
[0014] According to the exemplary construction illustrated in FIG.
1, drum plates 18 are arranged in circumferential relation to
rotatable shaft structure 12 and are oriented at an angle relative
to rotor 14. Thus, drum plates 18 and cup elements 20 supported
thereon are rotatable around axis lines disposed in angled relation
to the axis of rotatable shaft structure 12. According to the
exemplary construction, drum plates 18 are supported in this angled
orientation by curved surface support elements 40 alternatively
referred to as "ball guides" which are arranged around rotatable
shaft structure 12 outboard from rotor 14. As best illustrated
through joint reference to FIGS. 1 and 2, curved surface support
elements 40 include a convex exterior support surface 42 adapted to
engage a portion of drum plates 18. The curved surface support
elements 40 may further include an arrangement of detents 44 to
translate rotational movement to the surrounding drum plates
18.
[0015] By way of example only, and not limitation, it is
contemplated that curved surface support elements 40 may have a
substantially unitary construction such that detents 44 are formed
integrally with convex exterior support surface 42. Such structures
may be formed by casting, powder metallurgy, or other suitable
formation techniques using metal alloys or other materials adapted
to withstand substantial cyclical stresses. However, it is likewise
contemplated that portions of the curved surface support element 40
may be formed separately and thereafter joined together if desired.
According to a contemplate practice, the curved surface support
elements 40 may be formed separately from components of rotatable
shaft structure 12 such that curved surface support elements 40 are
non-integral with rotatable shaft structure 12. Curved surface
support elements 40 may thereafter be held in separable
relationship relative to rotatable shaft structure 12 during
operation. That is, curved surface support elements 40 may be
subject to nondestructive removal from rotatable shaft structure 12
upon disassembly of pump assembly 10.
[0016] FIG. 2 illustrates one exemplary arrangement for operative
connection between rotatable shaft structure 12 and a curved
surface support element 40. In the illustrated arrangement,
rotatable shaft structure 12 includes a splined collar 50 having a
pattern of ridges 52 extending longitudinally along a portion of
the collar 50. Ridges 52 are adapted to cooperatively engage a
pattern of spaced complimentary grooves 54 arranged around an
interior portion of curved surface support element 40. Accordingly,
curved surface support element 40 may slide over rotatable shaft
structure 12 until engaging splined collar 50. At splined collar
50, ridges 52 engage grooves 54 thereby preventing relative
rotational movement between curved surface support element 40 and
rotatable shaft structure 12. However, curved support element 40
may nonetheless retain the ability to engage in some degree of
sliding movement relative to rotatable shaft structure 12. Of
course, it is to be understood that the illustrated construction is
exemplary only and that any number of other constructions may
likewise be utilized. By way of example only, and not limitation,
in one such alternative arrangement the interlocking ridges and
grooves may be reversed if desired such that ridges are disposed at
the interior of curved surface support element 40 with
corresponding grooves being located along splined collar 50.
[0017] As illustrated, an arrangement of detents 44 may extend away
from curved surface support elements 40 for keyed engagement with
cooperating slot openings 46 in drum plates 18. As rotatable shaft
structure 12 is rotated, the rotational movement is translated to
drum plates 18 through curved surface support elements 40. As may
be seen through comparison of the upper and lower halves of FIG. 1,
due to the tilted arrangement of drum plates 18, the relative
position of detents 44 shifts axially along slot openings 46 during
the rotational cycle. To accommodate the shifting axial position of
detents 44, the slot openings 46 are of a generally elongated
configuration such that detents 44 can slide along the length of
the slot openings 46. The cross-sectional width of slot openings 46
may substantially correspond to the cross-sectional width of
detents 44 so as to maintain good rotational power transfer between
curved surface support elements 40 and drum plates 18.
[0018] In the exemplary construction curved surface support
elements 40 are continuously biased away from rotor 14 by use of an
arrangement of biasing elements 60 such as compression springs or
the like disposed at positions around rotatable shaft structure 12.
In this regard, it will be understood that biasing elements 60 may
be of different constructions on each side of rotor 14 as required
to conform to the body contours of rotor 14. In operation, biasing
elements 60 apply a compression force which operates along a line
of force substantially parallel to the axis of rotation of
rotatable shaft structure 12. The biasing elements 60 thus assist
in maintaining proper spacing between rotor 14 and curved surface
support elements 40 while simultaneously urging curved surface
support elements 40 away from rotor 14. As shown, biasing elements
may operate directly against rotor 14 and curved surface support
elements 40 without the need for intermediate ring structures,
although such intermediate ring structures may be used if
desired.
[0019] Force provided by biasing elements 60 is also utilized to
maintain pressure between outer wall portions of drum plates 18 and
inner wall portions of face plates 34. As will be appreciated,
maintaining such pressure may be beneficial in avoiding leakage
between those plate structures. In the illustrated construction,
drum plates 18 include an angled cheek portion 70 adapted to engage
a segment of convex exterior support surface 42. As shown, angled
cheek portion 70 is disposed at an outboard position relative to
detents 44 substantially along the line of force provided by
biasing element 60. In this regard, it is contemplated that the
cheek portions 70 may be integral to drum plates 18 or may be
formed as separate components. As curved surface support element 40
is urged away from rotor 14, pressure is applied against cheek
portion 70. Thus, a portion of the compressive force provided by
biasing element 60 is translated across curved surface support
element 40 to drum plate 18. Accordingly, both the curved surface
support element 40 and drum plate 18 are continuously urged away
from rotor 14 and drum plate 18 is pressed against face plate 34.
The continuous pressure of drum plate 18 against face plate 34 aids
in maintaining a contacting sealing relation between drum plate 18
and face plate 34. Fluid is thereby prevented from leaking between
drum plate 18 and face plate 34.
[0020] Although pump assembly 10 may be adapted for any number of
uses, according to one contemplated practice, a fluid may be
introduced through inlet port 30 which is aligned with openings in
drum plate 18 at a position where piston elements 16 are in the
maximum withdrawn state relative to corresponding cup elements 20.
In this orientation, variable volume chamber 24 has its maximum
capacity. As rotatable shaft structure 12 rotates, such rotational
movement is translated to rotor 14 and drum plates 18. As noted
previously, drum plates 18 are held in non-perpendicular angled
relation relative to the axis of rotation for rotatable shaft
structure 12 and rotor 14. Thus, as rotor 14 and drum plates 18
rotate, piston elements 16 are caused to move in a substantially
reciprocating manner within corresponding cup elements 20. As
piston elements 16 move further into cup element 20, pressure is
applied to fluid retained within variable volume chambers 24 such
that it may be expelled at outlet ports 32 at increased pressure if
desired. During rotation, curved surface support elements 40 are
held around rotatable shaft structure 12 such that the curved
surface support elements 40 rotate with rotatable shaft structure
12 while nonetheless being slidable longitudinally relative to
rotatable shaft structure 12. Biasing elements 60 continuously urge
curved surface support elements 40 outwardly away from rotor 14 so
as to maintain curved surface support element 40 at a desired
position. The biasing force provided by biasing element 60 is also
translated across the curved surface support elements 40 thereby
pressing drum plates 18 against outboard face plates 34 to assist
in maintaining leak free fluid passages.
INDUSTRIAL APPLICABILITY
[0021] The industrial applicability of the pump assembly described
herein will be readily appreciated from the foregoing discussion.
Pump assemblies consistent with the present disclosure may be used
to convey fluids through various systems in an efficient manner
while maintaining proper operative relation of the various
components. By way of example only, and not limitation, exemplary
fluids conveyed by the pump assembly may include cooling fluids,
lubricating fluids and the like.
[0022] In practice, a pump assembly consistent with this disclosure
may be utilized in environments such as industrial equipment, on
highway vehicles and the like where substantial durability is
required. In such environments, the use of biasing elements
operating in conjunction with a slidingly engaged curved support
element may tend to dampen vibrations and promote stability of
operation. Moreover, in the event of damage, the separable curved
support element may be replaced without the need to replace the
rotatable shaft structure. Accordingly, maintenance may be
substantially simplified.
* * * * *