US20160131118A1 - Tandem axial piston pump with shared cylinder block - Google Patents
Tandem axial piston pump with shared cylinder block Download PDFInfo
- Publication number
- US20160131118A1 US20160131118A1 US14/534,483 US201414534483A US2016131118A1 US 20160131118 A1 US20160131118 A1 US 20160131118A1 US 201414534483 A US201414534483 A US 201414534483A US 2016131118 A1 US2016131118 A1 US 2016131118A1
- Authority
- US
- United States
- Prior art keywords
- axial piston
- piston pump
- pistons
- tandem
- inlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
- F04B1/2014—Details or component parts
- F04B1/2078—Swash plates
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
- F04B1/2014—Details or component parts
- F04B1/2064—Housings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
- F04B1/22—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
- F04B1/22—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
- F04B1/24—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons inclined to the main shaft axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F04B1/26—Control
- F04B1/30—Control of machines or pumps with rotary cylinder blocks
- F04B1/32—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B23/00—Pumping installations or systems
- F04B23/04—Combinations of two or more pumps
- F04B23/06—Combinations of two or more pumps the pumps being all of reciprocating positive-displacement type
Definitions
- the present invention relates to axial piston pumps. More particularly, the invention relates to tandem axial piston pumps. Such hydraulic pumps can be found in the traction drive systems of skid steer construction vehicles and the like.
- the tandem axial piston pump will include two independently operable axial piston pump assemblies enclosed within a common housing.
- the invention provides a tandem axial piston pump.
- a first axial piston pump includes a first set of pistons arranged in a parallel, circular array and configured to reciprocate in response to rotation about a central axis.
- a second axial piston pump includes a second set of pistons arranged in a parallel, circular array and configured to reciprocate as they rotate about the central axis.
- a common drive shaft extends along the central axis, both the first and second sets of pistons being configured to rotate with the common drive shaft. Both the first and second sets of pistons are configured to reciprocate within corresponding separate first and second sets of cylinder bores of a common cylinder block.
- the invention provides a tandem axial piston pump.
- a drive shaft defines an axis.
- a first set of pistons are arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft.
- a second set of pistons are arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft.
- a first swash plate is coupled to a base end of each of the pistons of the first set. The first swash plate defines a cam angle with respect to the axis, and the cam angle defines a stoke distance through which each of the pistons of the first set travels back-and-forth upon a rotation about the axis.
- a second swash plate is coupled to a base end of each of the pistons of the second set.
- the second swash plate defines a cam angle with respect to the axis, and the cam angle defines a stoke distance through which each of the pistons of the second set travels back-and-forth upon a rotation about the axis.
- a cylinder block has a first set of cylinder bores receiving the first set of pistons from a first end of the cylinder block and a second set of cylinder bores receiving the second set of pistons from a second end of the cylinder block, opposite the first end.
- FIG. 1 is a perspective view of a tandem axial piston pump.
- FIG. 2 is an exploded assembly view of the tandem axial piston pump of FIG. 1 .
- FIG. 3 is a cross-section view of the tandem axial piston pump, taken along line 3 - 3 of FIG. 1 .
- FIG. 4 is a perspective view of a tandem axial piston pump according to a second embodiment.
- FIG. 5 is an exploded assembly view of the tandem axial piston pump of FIG. 4 .
- FIG. 6 is a cross-section view of the tandem axial piston pump, taken along line 6 - 6 of FIG. 4 .
- FIGS. 1-3 illustrate a tandem axial piston pump 20 according to one embodiment.
- the tandem axial piston pump 20 is a type of variable displacement fluid pump in which two pump units are provided.
- the two pump units are separately controllable. In other words, the displacement or flow rate of each pump unit can be varied independently.
- Each pump unit includes one set of pistons 24 arranged in a parallel, circular array and configured to reciprocate with a variable stroke in response to rotation about a central axis A.
- the two sets of pistons 24 are arranged so that one set is positioned on each side of a central plane P.
- the pistons 24 of the two sets can all be identical as shown. In other constructions, some or all of the pistons 24 can have different characteristics from those shown.
- a cylinder block 28 is provided with separate first and second sets of cylinder bores 30 corresponding to the two sets of pistons 24 .
- the two sets of cylinder bores 30 are provided in two opposing axial ends of the cylinder block 28 , with one set of cylinder bores 30 positioned on each side of the central plane P.
- the cylinder bores 30 of the first set can be arranged on a circle of common diameter with the cylinder bores 30 of the second set. Additionally, the arrangement or pattern of the cylinder bores 30 along the circumferential direction is common between the two sets such that each cylinder bore 30 of the first set is aligned with a corresponding cylinder bore 30 of the second set as shown in FIG. 3 . However, other relative orientations are optional.
- the cylinder block 28 is a singular unit, such that the tandem axial piston pump 20 is not provided with two separate cylinder blocks for the two separate pump units and is not provided with any valve plate positioned adjacent the inward ends of the cylinder bores 30 .
- the cylinder block 28 is integrally formed as a single, monolithic piece.
- a common drive shaft 34 extends along the central axis A and is drivingly coupled to the cylinder block 28 to rotate both the cylinder block 28 and both sets of pistons 24 about the axis A.
- the drive shaft 34 can be supported for rotation by suitable bearings 36 .
- the bearings 36 are positioned adjacent opposing ends of the drive shaft 34 to support the drive shaft 34 relative to a pair of axially opposed end flanges 40 , 42 .
- Each of the end flanges 40 , 42 is secured to a corresponding housing portion 44 , 46 of the tandem axial piston pump 20 .
- a port block 48 is sandwiched between the two housing portions 44 , 46 .
- the cylinder block 28 extends through a bore 50 in the port block 48 .
- the bore 50 is positioned generally at the central plane P (e.g., the bore 50 may be centered on, or overlapping with, the central plane P).
- Each piston 24 has an inner working end facing the central plane P and an outer drive end.
- the drive end of each piston 24 has a rounded shape received in a corresponding piston shoe 60 .
- the piston shoes 60 of each set of pistons 24 are collectively retained by a shoe plate 62 to maintain the parallel spaced arrangement of the pistons 24 within each set.
- a swash plate 66 Directly outside the piston shoes 60 in the axial direction on each pump unit is a swash plate 66 .
- the swash plates 66 are movable to tilt relative to the central axis A in order to vary the stroke of the corresponding pistons 24 .
- the swash plates 66 are illustrated in a zero or neutral state in which the swash plates 66 are each arranged exactly perpendicular to the central axis A such that the pistons 24 do not stroke at all when the pistons 24 and the cylinder block 28 are rotated about the central axis A.
- each piston 24 of the corresponding pump unit reciprocates to complete one back-and-forth pumping stroke within the corresponding bore 30 upon each full rotation of the cylinder block 28 about the central axis A.
- the linear stroke of the pistons 24 of a particular set is varied by varying the angle of the corresponding swash plate 66 .
- the independence of the displacement between the two pump units, which rotate together, is achieved by independent control of the two swash plates 66 .
- a radial bore 70 or connector port is provided through an outer cylindrical surface 72 of the cylinder block 28 for each of the cylinder bores 30 of each of the two sets.
- Each radial bore 70 extends inward from the outer cylindrical surface 72 to intersect with the corresponding cylinder bore 30 to establish fluid communication therewith.
- the radial bores 70 provide fluid communication with the port block 48 via one or more distribution rings 76 as discussed further below. Although shown as two separate components in the illustrated construction, the features of the two distribution rings 76 can alternately be incorporated into a single distribution ring.
- Each of the distribution rings 76 is fixed to the bore 50 in the port block 48 . For example, the distribution rings 76 can be press-fit into the bore 50 .
- the cylinder block 28 is provided in tight sliding relationship with the interior of each of the distribution rings 76 .
- the radial bores 70 are brought into and out of fluid communication with a pair of slots 80 , 82 provided in each distribution ring 76 .
- the two slots 80 , 82 in each distribution ring 76 are circumferentially spaced apart, and may be diametrically opposed.
- Each of the slots 80 , 82 may be about 90 arc degrees long, or more.
- the first slot 80 is a pickup or inlet slot which is in permanent fluid communication with a corresponding inlet port 86 of the port block 48 , via a connecting passage through the port block 48 .
- the second slot 82 is a distribution or outlet slot which is in permanent fluid communication with a corresponding outlet port 88 of the port block 48 , via a connecting passage through the port block 48 . Because the pump 20 includes two pump units, the port block 48 includes two separate pairs of the inlet and outlet ports 86 , 88 corresponding to the two pump units.
- each piston 24 of the corresponding pump unit moves in a retracting direction with respect to the corresponding cylinder bore 30 over a rotational range in which the corresponding radial bore 70 is in communication with the corresponding inlet slot 80 , and thereby, the inlet port 86 .
- fluid is drawn into the cylinder bore 30 through the inlet port 86 , the inlet slot 80 , and the radial bore 70 .
- Further rotation of the cylinder block 28 causes fluid communication to cease between the cylinder bore 30 and the inlet slot 80 , and even further rotation of the cylinder block 28 causes fluid communication to be established between the cylinder bore 30 and the outlet slot 82 .
- the piston 24 extends into the cylinder bore 30 over a rotational range in which the corresponding radial bore 70 is in communication with the outlet slot 82 .
- the fluid previously drawn into the cylinder bore 30 from the inlet port 86 is pumped out of the pump 20 from the cylinder bore 30 through the radial bore 70 , the outlet slot 82 , and the outlet port 88 .
- Each sequential piston 24 of the given pump unit follows the same sequence during rotation of the cylinder block 28 , and if the swash plate 66 of the other pump unit is angled, a similar pumping method occurs with the other set of pistons 24 .
- a separate mechanism e.g., a servo motor
- the drive shaft 34 may be rotated by a separate drive element (e.g., an electric motor) at a constant speed during operation of the pump 20 .
- FIGS. 4-6 illustrate a tandem axial piston pump 120 according to a second embodiment.
- Components and functions of the pump 120 of FIGS. 4-6 are similar to those of the pump 20 of FIGS. 1-3 and thus, are not reiterated below. Similar components are given similar reference numbers, incremented by a leading “1”, and the below description focuses primarily on the features of the pump 120 which are different from the pump 20 of FIGS. 1-3 .
- the pump 120 is provided with a two-piece case consisting of a first case portion 143 A and a second case portion 143 B.
- the case portions 143 A, 143 B can be mated to one another (e.g., by a plurality of fasteners or other means, not shown) in a direction parallel to the axis A.
- Both case portions 143 A, 143 B generally have a cup shape which surrounds at least a portion of the pump internals both radially and on one axial end.
- each case portion 143 A, 143 B includes a control bore 145 A, 145 B for receiving a servo piston or stroking piston (not shown) which manipulates the corresponding swash plate 166 A, 166 B, a drive portion 167 of which is positioned in the corresponding control bore 145 A, 145 B.
- the swash plates 166 A, 166 B are movable to different angles independently of one another to vary the displacement of each pump unit of the tandem axial piston pump 120 .
- the tandem axial piston pump 120 also does without a separate central port block, instead providing both the inlet ports 186 and the outlet ports 188 for both pump units in the second case portion 143 B.
- the inlet ports 186 for both pump units can be located on a first side of the second case portion 143 B and the outlet ports 188 for both pump units can be located on a second opposite side of the second case portion 143 B, although other arrangements are optional.
- the arrangement of the cylinder bores 130 (and thus, the corresponding pistons 124 ) is altered from that of the pump 20 of FIGS. 1-3 .
- the cylinder bores 130 of the two sets are positioned to overlap axially across each other. As shown, each of the cylinder bores 130 crosses over the central plane P. In order to facilitate the overlap, the cylinder bores 130 of the two sets are not aligned with each other.
- the cylinder bores 130 of one set can be arranged on a circle of a first diameter, with the cylinder bores 30 of the second set arranged on a circle of a second diameter that is smaller than or greater than the first diameter such that the cylinder bores 130 of one set are effectively arranged radially inside or outside the cylinder bores 130 of the second set.
- the arrangement or pattern of the cylinder bores 130 along the circumferential direction can be offset from one set to the other.
- the cylinder bores 130 of the two sets are arranged on circles of different diameter and also offset in the circumferential direction. This makes an efficient use of the volume defined by the cylinder block 128 and an axial length of the cylinder block 128 can be reduced.
- each and every piston 124 within the tandem axial piston pump 120 can be identical, although not required.
- the cylinder block 128 rotates with one or more distribution rings 176 having respective inlet and outlet slots 180 , 182 for the two pump units provided by the cylinder block 128 .
- the features of the two distribution rings 176 can alternately be incorporated into a single distribution ring.
- the distribution ring(s) can be fixed to a bore 150 provided in the second case portion 143 B.
- the distribution rings 176 can be press-fit into the bore 150 .
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Reciprocating Pumps (AREA)
Abstract
Description
- The present invention relates to axial piston pumps. More particularly, the invention relates to tandem axial piston pumps. Such hydraulic pumps can be found in the traction drive systems of skid steer construction vehicles and the like. The tandem axial piston pump will include two independently operable axial piston pump assemblies enclosed within a common housing.
- In one aspect, the invention provides a tandem axial piston pump. A first axial piston pump includes a first set of pistons arranged in a parallel, circular array and configured to reciprocate in response to rotation about a central axis. A second axial piston pump includes a second set of pistons arranged in a parallel, circular array and configured to reciprocate as they rotate about the central axis. A common drive shaft extends along the central axis, both the first and second sets of pistons being configured to rotate with the common drive shaft. Both the first and second sets of pistons are configured to reciprocate within corresponding separate first and second sets of cylinder bores of a common cylinder block.
- In another aspect, the invention provides a tandem axial piston pump. A drive shaft defines an axis. A first set of pistons are arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft. A second set of pistons are arranged in parallel with the axis in a circular array and rotatable about the axis by the drive shaft. A first swash plate is coupled to a base end of each of the pistons of the first set. The first swash plate defines a cam angle with respect to the axis, and the cam angle defines a stoke distance through which each of the pistons of the first set travels back-and-forth upon a rotation about the axis. A second swash plate is coupled to a base end of each of the pistons of the second set. The second swash plate defines a cam angle with respect to the axis, and the cam angle defines a stoke distance through which each of the pistons of the second set travels back-and-forth upon a rotation about the axis. A cylinder block has a first set of cylinder bores receiving the first set of pistons from a first end of the cylinder block and a second set of cylinder bores receiving the second set of pistons from a second end of the cylinder block, opposite the first end.
- Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
-
FIG. 1 is a perspective view of a tandem axial piston pump. -
FIG. 2 is an exploded assembly view of the tandem axial piston pump ofFIG. 1 . -
FIG. 3 is a cross-section view of the tandem axial piston pump, taken along line 3-3 ofFIG. 1 . -
FIG. 4 is a perspective view of a tandem axial piston pump according to a second embodiment. -
FIG. 5 is an exploded assembly view of the tandem axial piston pump ofFIG. 4 . -
FIG. 6 is a cross-section view of the tandem axial piston pump, taken along line 6-6 ofFIG. 4 . - Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
-
FIGS. 1-3 illustrate a tandemaxial piston pump 20 according to one embodiment. The tandemaxial piston pump 20 is a type of variable displacement fluid pump in which two pump units are provided. The two pump units are separately controllable. In other words, the displacement or flow rate of each pump unit can be varied independently. Each pump unit includes one set ofpistons 24 arranged in a parallel, circular array and configured to reciprocate with a variable stroke in response to rotation about a central axis A. The two sets ofpistons 24 are arranged so that one set is positioned on each side of a central plane P. Thepistons 24 of the two sets can all be identical as shown. In other constructions, some or all of thepistons 24 can have different characteristics from those shown. Acylinder block 28 is provided with separate first and second sets ofcylinder bores 30 corresponding to the two sets ofpistons 24. The two sets ofcylinder bores 30 are provided in two opposing axial ends of thecylinder block 28, with one set ofcylinder bores 30 positioned on each side of the central plane P. The cylinder bores 30 of the first set can be arranged on a circle of common diameter with thecylinder bores 30 of the second set. Additionally, the arrangement or pattern of the cylinder bores 30 along the circumferential direction is common between the two sets such that each cylinder bore 30 of the first set is aligned with acorresponding cylinder bore 30 of the second set as shown inFIG. 3 . However, other relative orientations are optional. Thecylinder block 28 is a singular unit, such that the tandemaxial piston pump 20 is not provided with two separate cylinder blocks for the two separate pump units and is not provided with any valve plate positioned adjacent the inward ends of thecylinder bores 30. In some constructions, thecylinder block 28 is integrally formed as a single, monolithic piece. Acommon drive shaft 34 extends along the central axis A and is drivingly coupled to thecylinder block 28 to rotate both thecylinder block 28 and both sets ofpistons 24 about the axis A. Thedrive shaft 34 can be supported for rotation bysuitable bearings 36. Thebearings 36 are positioned adjacent opposing ends of thedrive shaft 34 to support thedrive shaft 34 relative to a pair of axiallyopposed end flanges end flanges corresponding housing portion axial piston pump 20. As discussed further below, aport block 48 is sandwiched between the twohousing portions cylinder block 28 extends through abore 50 in theport block 48. Thebore 50 is positioned generally at the central plane P (e.g., thebore 50 may be centered on, or overlapping with, the central plane P). - Each
piston 24 has an inner working end facing the central plane P and an outer drive end. The drive end of eachpiston 24 has a rounded shape received in acorresponding piston shoe 60. Thepiston shoes 60 of each set ofpistons 24 are collectively retained by ashoe plate 62 to maintain the parallel spaced arrangement of thepistons 24 within each set. Directly outside thepiston shoes 60 in the axial direction on each pump unit is aswash plate 66. Theswash plates 66 are movable to tilt relative to the central axis A in order to vary the stroke of thecorresponding pistons 24. Theswash plates 66 are illustrated in a zero or neutral state in which theswash plates 66 are each arranged exactly perpendicular to the central axis A such that thepistons 24 do not stroke at all when thepistons 24 and thecylinder block 28 are rotated about the central axis A. When one of theswash plates 66 is angled away from the neutral state, eachpiston 24 of the corresponding pump unit reciprocates to complete one back-and-forth pumping stroke within thecorresponding bore 30 upon each full rotation of thecylinder block 28 about the central axis A. The linear stroke of thepistons 24 of a particular set is varied by varying the angle of thecorresponding swash plate 66. The independence of the displacement between the two pump units, which rotate together, is achieved by independent control of the twoswash plates 66. - A
radial bore 70 or connector port is provided through an outercylindrical surface 72 of thecylinder block 28 for each of thecylinder bores 30 of each of the two sets. Eachradial bore 70 extends inward from the outercylindrical surface 72 to intersect with thecorresponding cylinder bore 30 to establish fluid communication therewith. Theradial bores 70 provide fluid communication with theport block 48 via one ormore distribution rings 76 as discussed further below. Although shown as two separate components in the illustrated construction, the features of the twodistribution rings 76 can alternately be incorporated into a single distribution ring. Each of the distribution rings 76 is fixed to thebore 50 in theport block 48. For example, the distribution rings 76 can be press-fit into thebore 50. Thecylinder block 28, particularly the outercylindrical surface 72, is provided in tight sliding relationship with the interior of each of the distribution rings 76. Thus, as thecylinder block 28 rotates within the distribution rings 76, the radial bores 70 are brought into and out of fluid communication with a pair ofslots distribution ring 76. The twoslots distribution ring 76 are circumferentially spaced apart, and may be diametrically opposed. Each of theslots first slot 80 is a pickup or inlet slot which is in permanent fluid communication with acorresponding inlet port 86 of theport block 48, via a connecting passage through theport block 48. Thesecond slot 82 is a distribution or outlet slot which is in permanent fluid communication with acorresponding outlet port 88 of theport block 48, via a connecting passage through theport block 48. Because thepump 20 includes two pump units, theport block 48 includes two separate pairs of the inlet andoutlet ports - When the
swash plate 66 of one of the pump units is angled from the illustrated neutral position, eachpiston 24 of the corresponding pump unit moves in a retracting direction with respect to the corresponding cylinder bore 30 over a rotational range in which the corresponding radial bore 70 is in communication with thecorresponding inlet slot 80, and thereby, theinlet port 86. As such, fluid is drawn into the cylinder bore 30 through theinlet port 86, theinlet slot 80, and the radial bore 70. Further rotation of thecylinder block 28 causes fluid communication to cease between the cylinder bore 30 and theinlet slot 80, and even further rotation of thecylinder block 28 causes fluid communication to be established between the cylinder bore 30 and theoutlet slot 82. Due to the angle of theswash plate 66, thepiston 24 extends into the cylinder bore 30 over a rotational range in which the corresponding radial bore 70 is in communication with theoutlet slot 82. As such, the fluid previously drawn into the cylinder bore 30 from theinlet port 86 is pumped out of thepump 20 from the cylinder bore 30 through the radial bore 70, theoutlet slot 82, and theoutlet port 88. Eachsequential piston 24 of the given pump unit follows the same sequence during rotation of thecylinder block 28, and if theswash plate 66 of the other pump unit is angled, a similar pumping method occurs with the other set ofpistons 24. Although not shown in the drawings, a separate mechanism (e.g., a servo motor) may be coupled to therespective swash plates 66 to control the swash angles and thus, the pump displacement. While not necessarily limited to one fixed speed, thedrive shaft 34 may be rotated by a separate drive element (e.g., an electric motor) at a constant speed during operation of thepump 20. -
FIGS. 4-6 illustrate a tandemaxial piston pump 120 according to a second embodiment. Components and functions of thepump 120 ofFIGS. 4-6 are similar to those of thepump 20 ofFIGS. 1-3 and thus, are not reiterated below. Similar components are given similar reference numbers, incremented by a leading “1”, and the below description focuses primarily on the features of thepump 120 which are different from thepump 20 ofFIGS. 1-3 . - Rather than having separate housings and end flanges on each end, the
pump 120 is provided with a two-piece case consisting of afirst case portion 143A and asecond case portion 143B. Thecase portions case portions case portion control bore swash plate drive portion 167 of which is positioned in the corresponding control bore 145A, 145B. Similar to thepump 20 ofFIGS. 1-3 , theswash plates axial piston pump 120. - The tandem
axial piston pump 120 also does without a separate central port block, instead providing both theinlet ports 186 and theoutlet ports 188 for both pump units in thesecond case portion 143B. Theinlet ports 186 for both pump units can be located on a first side of thesecond case portion 143B and theoutlet ports 188 for both pump units can be located on a second opposite side of thesecond case portion 143B, although other arrangements are optional. - In order to further limit an axial length of the
cylinder block 128 to reduce the overall packaging size of the tandemaxial piston pump 120, the arrangement of the cylinder bores 130 (and thus, the corresponding pistons 124) is altered from that of thepump 20 ofFIGS. 1-3 . Rather than being entirely positioned on one side of the central plane P that bisects thecylinder block 128, the cylinder bores 130 of the two sets are positioned to overlap axially across each other. As shown, each of the cylinder bores 130 crosses over the central plane P. In order to facilitate the overlap, the cylinder bores 130 of the two sets are not aligned with each other. Instead, the cylinder bores 130 of one set can be arranged on a circle of a first diameter, with the cylinder bores 30 of the second set arranged on a circle of a second diameter that is smaller than or greater than the first diameter such that the cylinder bores 130 of one set are effectively arranged radially inside or outside the cylinder bores 130 of the second set. Alternately or additionally, the arrangement or pattern of the cylinder bores 130 along the circumferential direction can be offset from one set to the other. In the illustrated construction, the cylinder bores 130 of the two sets are arranged on circles of different diameter and also offset in the circumferential direction. This makes an efficient use of the volume defined by thecylinder block 128 and an axial length of thecylinder block 128 can be reduced. Although therespective swash plates shoe plates piston 124 within the tandemaxial piston pump 120 can be identical, although not required. - Similar to the
pump 20 ofFIGS. 1-3 , thecylinder block 128 rotates with one or more distribution rings 176 having respective inlet andoutlet slots cylinder block 128. Although shown as two separate components in the illustrated construction, the features of the two distribution rings 176 can alternately be incorporated into a single distribution ring. The distribution ring(s) can be fixed to abore 150 provided in thesecond case portion 143B. For example, the distribution rings 176 can be press-fit into thebore 150. The above description of the tandemaxial piston pump 20 is hereby referenced with respect to all additional structural and operational details, and alternatives thereof, the full repetition of which would be redundant. - Various features and advantages of the invention are set forth in the following claims.
Claims (19)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/534,483 US20160131118A1 (en) | 2014-11-06 | 2014-11-06 | Tandem axial piston pump with shared cylinder block |
PCT/US2015/058727 WO2016073412A1 (en) | 2014-11-06 | 2015-11-03 | Tandem axial piston pump with shared cylinder block |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/534,483 US20160131118A1 (en) | 2014-11-06 | 2014-11-06 | Tandem axial piston pump with shared cylinder block |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160131118A1 true US20160131118A1 (en) | 2016-05-12 |
Family
ID=54541237
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/534,483 Abandoned US20160131118A1 (en) | 2014-11-06 | 2014-11-06 | Tandem axial piston pump with shared cylinder block |
Country Status (2)
Country | Link |
---|---|
US (1) | US20160131118A1 (en) |
WO (1) | WO2016073412A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10247178B2 (en) * | 2016-03-28 | 2019-04-02 | Robert Bosch Gmbh | Variable displacement axial piston pump with fluid controlled swash plate |
CN109989898A (en) * | 2019-05-15 | 2019-07-09 | 梁德荣 | Inclined seal ring flow-distribution mechanism, axial piston motor and axial plunger pump |
CN116717453A (en) * | 2023-08-09 | 2023-09-08 | 潍坊万隆电气股份有限公司 | Air conditioner compressor |
US20230358220A1 (en) * | 2022-05-04 | 2023-11-09 | Caterpillar Inc. | Pump having a flange for mounting an auxiliary pump |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114249258B (en) * | 2020-09-23 | 2023-03-24 | 中联重科股份有限公司 | Rotary driving mechanism, arm support assembly and engineering machinery |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1780398A (en) * | 1929-08-24 | 1930-11-04 | Timken Axle Co Detroit | Air compressor |
US2430753A (en) * | 1943-11-08 | 1947-11-11 | Ziska Adam | Pump |
US2691350A (en) * | 1951-09-10 | 1954-10-12 | Greer Hydraulics Inc | Hydraulic equipment |
US2860581A (en) * | 1954-09-23 | 1958-11-18 | Cecil C Buckner | Fluid pumps |
US3731593A (en) * | 1969-03-13 | 1973-05-08 | Uulkan Kupplungs U Getriebebau | Axial piston pump |
US3776102A (en) * | 1971-03-03 | 1973-12-04 | Tokico Ltd | Variable-displacement type fluid pump or motor |
US20130284011A1 (en) * | 2010-11-25 | 2013-10-31 | Technoboost | Variable displacement hydraulic machine, in particular for a motor vehicle |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55158281U (en) * | 1979-05-02 | 1980-11-13 | ||
EP0158084B1 (en) * | 1984-02-29 | 1990-05-30 | Shimadzu Corporation | Bent axis type axial piston pump or motor |
US6793463B1 (en) * | 2000-10-30 | 2004-09-21 | Hydro-Gear Limited Partnership | Tandem pump and interface for same |
DE102005037618A1 (en) * | 2005-05-20 | 2006-11-23 | Brueninghaus Hydromatik Gmbh | Hydrostatic piston machine according to the floating cup concept |
EP1748189B1 (en) * | 2005-07-27 | 2012-09-26 | Poclain Hydraulics | Tandem axial piston pump unit |
DE102005058938A1 (en) * | 2005-11-11 | 2007-05-16 | Brueninghaus Hydromatik Gmbh | Hydrostatic piston machine |
DE102006021570A1 (en) * | 2006-04-10 | 2007-10-18 | Robert Bosch Gmbh | Hydrostatic piston machine with rotating control disc |
JP5027878B2 (en) * | 2007-07-31 | 2012-09-19 | カヤバ工業株式会社 | Tandem piston pump |
-
2014
- 2014-11-06 US US14/534,483 patent/US20160131118A1/en not_active Abandoned
-
2015
- 2015-11-03 WO PCT/US2015/058727 patent/WO2016073412A1/en active Application Filing
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1780398A (en) * | 1929-08-24 | 1930-11-04 | Timken Axle Co Detroit | Air compressor |
US2430753A (en) * | 1943-11-08 | 1947-11-11 | Ziska Adam | Pump |
US2691350A (en) * | 1951-09-10 | 1954-10-12 | Greer Hydraulics Inc | Hydraulic equipment |
US2860581A (en) * | 1954-09-23 | 1958-11-18 | Cecil C Buckner | Fluid pumps |
US3731593A (en) * | 1969-03-13 | 1973-05-08 | Uulkan Kupplungs U Getriebebau | Axial piston pump |
US3776102A (en) * | 1971-03-03 | 1973-12-04 | Tokico Ltd | Variable-displacement type fluid pump or motor |
US20130284011A1 (en) * | 2010-11-25 | 2013-10-31 | Technoboost | Variable displacement hydraulic machine, in particular for a motor vehicle |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10247178B2 (en) * | 2016-03-28 | 2019-04-02 | Robert Bosch Gmbh | Variable displacement axial piston pump with fluid controlled swash plate |
CN109989898A (en) * | 2019-05-15 | 2019-07-09 | 梁德荣 | Inclined seal ring flow-distribution mechanism, axial piston motor and axial plunger pump |
US20230358220A1 (en) * | 2022-05-04 | 2023-11-09 | Caterpillar Inc. | Pump having a flange for mounting an auxiliary pump |
CN116717453A (en) * | 2023-08-09 | 2023-09-08 | 潍坊万隆电气股份有限公司 | Air conditioner compressor |
Also Published As
Publication number | Publication date |
---|---|
WO2016073412A1 (en) | 2016-05-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20160131118A1 (en) | Tandem axial piston pump with shared cylinder block | |
EP3020969B1 (en) | Pump arrangement | |
EP2177759A1 (en) | Tandem piston pump | |
US4297086A (en) | Fluid motor-pump unit | |
JP2016533447A5 (en) | ||
US9097113B2 (en) | Hydraulic pump/motor and method of suppressing pulsation of hydraulic pump/motor | |
US20170138335A1 (en) | Hydrostatic radial piston machine | |
US10443583B2 (en) | Vibratory drive with hydraulic pulse generator | |
US20210048022A1 (en) | Split power gerotor pump | |
WO2018215514A1 (en) | Hydrostatic relief and lubrication notches on valve segment running face | |
US10400742B2 (en) | Hydraulic machine with floating cylinders | |
US20090274564A1 (en) | Floating cup pump having swashplate mounted cup elements | |
US10012219B2 (en) | Hydrostatic variable displacement axial piston machine, in particular hydrostatic variable displacement axial piston motor | |
US5401144A (en) | Swash plate type refrigerant compressor | |
KR100546470B1 (en) | A hydraulic rotating axial piston engine | |
US2453128A (en) | Transmission | |
EP3237754B1 (en) | Hydrostatic pump barrel with sloped kidney ports | |
CN214577561U (en) | Bent axle type axial piston hydraulic press | |
US4090817A (en) | High displacement-to-size ratio rotary fluid mechanism | |
EP3020967B1 (en) | Pump device | |
US3805675A (en) | Independent variable multiflow high pressure pump | |
US10273946B2 (en) | Rotary fluid device with bent cylinder sleeves | |
JP2874258B2 (en) | Multiple piston pump | |
KR100474258B1 (en) | Swash Plate Type Axial Piston Pump | |
US6358025B1 (en) | Hydraulic rotating axial piston engine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: ROBERT BOSCH GMBH, GERMANY Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WEATHERSBEE, MICHAEL;KALOCY, RICHARD;STEWART, JONATHAN;REEL/FRAME:034117/0542 Effective date: 20141104 Owner name: BOSCH REXROTH CORPORATION, ILLINOIS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WEATHERSBEE, MICHAEL;KALOCY, RICHARD;STEWART, JONATHAN;REEL/FRAME:034117/0542 Effective date: 20141104 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |