US20050166751A1 - Hydro transformer - Google Patents
Hydro transformer Download PDFInfo
- Publication number
- US20050166751A1 US20050166751A1 US10/516,728 US51672805A US2005166751A1 US 20050166751 A1 US20050166751 A1 US 20050166751A1 US 51672805 A US51672805 A US 51672805A US 2005166751 A1 US2005166751 A1 US 2005166751A1
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- US
- United States
- Prior art keywords
- control
- hydraulic transformer
- accordance
- displacers
- volume
- 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
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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
- F04B1/26—Control
- F04B1/30—Control of machines or pumps with rotary cylinder blocks
- F04B1/303—Control of machines or pumps with rotary cylinder blocks by turning the valve plate
-
- 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
- F04B1/2042—Valves
Definitions
- the invention relates to a hydraulic transformer in accordance with the preamble of claim 1 .
- a hydraulic transformer is a unit wherein an energy flow Q 1 ⁇ p 1 is transformed into an energy flow Q 2 ⁇ p 2 through hydraulic coupling of a hydrostatic motor and a pump. In the process, only the amount of hydraulic energy required for driving a consumer that is connected to the pump is withdrawn from an existing pressure supply.
- Such hydraulic transformers may be designed as radial piston engines, axial piston engines, or in accordance with other kinematic function principles, e.g., as vane-cell machines.
- U.S. Pat. No. 3,188,963 discloses a hydraulic transformer having the form of a swashplate motor, wherein displacers guided in a rotatable cylinder are supported on a stationary swash plate. The angle of the swash plate determines the piston stroke of the displacers. Pressure medium supply and discharge are performed with the aid of a control disc having four control kidneys, wherein the respective pairs of control kidneys are associated with the motor and the pump.
- the displacer chambers are inherently also shifted outside of the dead center positions, wherein this shifting may take place at arbitrary piston velocities. Shifting takes place within a substantially smaller rotational angle interval in comparison with pumps and motors, so that comparatively high pressure gradients may occur, which may lead to excessively high mechanical strains on the hydraulic transformer and high noise emission.
- the invention is based on the object of providing a hydraulic transformer wherein the load is reduced by pressure gradients in the commutation range.
- the hydraulic transformer is provided with a multiplicity of displacers each guided in a displacer chamber and capable of being connected through commutation means including a pressure port, a consumer port, or a tank port, the relative position of the commutation means being variable relative to the dead center positions of the displacers.
- the oil volume of the displacer chamber to be shifted is increased during the commutation phase. This is achieved in particular in that in this commutation phase, the respective displacer volume is connected with a commutation chamber.
- control means include three control recesses distributed at the periphery, with the commutation chambers opening into respective ranges between two adjacent control recesses.
- control recesses have an approximate kidney shape, and the commutation chambers each open into one of the kidney separation webs.
- control kidneys and through bores of the commutation chambers are formed in a control disc of the control means.
- the commutation means have next to the control disc a base body in which a part of the commutation chamber is formed next to the through bores of the control disc.
- each commutation chamber is greater or at least equal to the displacement volume of a displacer.
- the volume of the commutation chamber should, however, preferably be less than five times the displacement volume. This range may, however, vary in accordance with system pressure, switching frequency, and geometry of the control bores.
- the hydraulic transformer of the invention preferably has the form of an axial piston bent-axis unit. As was already mentioned at the outset, the invention may also be applied in other kinematic functional principles for hydraulic transformers.
- FIG. 1 is a three-dimensional representation of a hydraulic transformer in bent-axis design
- FIG. 2 is a front view of a control member of the hydraulic transformer of FIG. 1 ;
- FIG. 3 is a three-dimensional representation of the control member of FIG. 2 ;
- FIG. 4 is a longitudinal sectional view of the control member of FIGS. 2 and 3 .
- FIG. 1 shows a three-dimensional schematic representation of a hydraulic transformer 1 executed in bent-axis design.
- a like hydraulic transformer 1 may be represented as a combination of a hydrostatic motor and a hydraulic pump mechanically coupled to each other.
- hydraulic transformers may be realized through variable displacer units, with axial piston machines or vane cell machines preferably being used. Fundamentally it is, however, possible to employ any displacer unit where the displacers may be controlled such that they may successively be taken into operative connection with three pressure levels: the supply pressure, the tank pressure, and the consumer pressure (work pressure).
- the hydraulic transformer 1 in accordance with FIG. 1 includes an angled housing 2 in which displacers guided inside a cylinder drum, a drive flange, and a drive shaft are arranged.
- a control housing 4 is attached which is closed by a cap 5 .
- Supply and discharge of the pressure medium to and from the cylinder chambers is effected through a control member 12 accommodated in the control housing 4 which may be adjusted to vary the transmission ratio between pump and motor.
- the commutation means may be adjusted in relation to the dead center positions of the displacers with the aid of adjusting means, such as with the aid of an electric motor 6 or any other suitable drive mechanism, e.g., a gear drive.
- a work port B On the angled housing 2 and on the cap 5 a work port B, a tank port T, and a supply port A are provided. These ports may be executed as axial or radial ports.
- bent-axis unit including the displacers
- the construction of the bent-axis unit including the displacers is sufficiently known from the prior art.
- the control member 12 of FIGS. 2 to 4 is rotatably mounted in the control housing 4 and includes at its outer periphery a flange 14 for axial contact with a gear (not shown). By means of this gear it is possible to adjust the control member 12 in relation to the dead center positions of the displacers.
- the control member 12 hat on its end-face side (view of FIG. 2 ) a control disc 16 which sealingly contacts the cylinder drum rotatably mounted in the angled housing 2 . Inside this cylinder drum, the displacers are guided which are translatable in an axial direction and supported on a bent axis.
- Three control kidneys 18 , 20 , 22 distributed on the periphery extend through the control disc 16 . Between two respective adjacent control kidneys there remains a kidney separation web 25 into which an axial blind bore 23 , 27 or 29 opens.
- control disc 16 is part of a base body 24 , at the outer periphery of which the flange 14 is formed.
- connection passages 26 , 28 , 30 are formed whereby the control kidneys 18 , 20 and 22 , respectively, are connected with the associated pressure medium ports.
- control kidney 18 is connected via the connection passage 26 and radially merging passages 32 with the tank port T
- control kidney 20 is connected via the connection passage 28 and an oblique passage 36 extending obliquely to the axis 34 of the control member 12 with the consumer or work port B
- control kidney 22 is connected via three bores 38 extending in parallel with the axis with the supply port A.
- the displacers may be subjected to the pressure at the tank port T, at the work port B, or at the supply port A.
- the width of the kidney separation webs 25 is selected such that a displacer volume may be covered by the kidney separation web 25 in the commutation phase between two adjacent control kidneys. In conventional solutions, these kidney separation webs are closed, so that in the commutation phase a complete coverage of the displacer chamber ensues.
- the displacer chambers located in the range of the kidney separation webs 25 are connected with dead spaces 40 , 42 and 44 represented in FIG. 3 via the blind bores 23 , 27 and 29 . These have the form of axial and radial or oblique bore sections in the base body 24 and are represented externally of the control member 12 in FIG. 3 for the sake of clarity.
- the dead space 44 is essentially formed by a centrally arranged, axially extending cavity that is connected with the blind bore 29 through a transverse bore.
- the two commutation chambers 40 and 42 are formed by radially offset bore sections substantially extending in the axial direction and interconnected by respective oblique or radial bores.
- the dead space 44 is closed against the control disc 16 by a screw plug 45 .
- the axially extending bores of the two other dead spaces are introduced into the end face side of the control member 12 facing away from the control disc 16 and are closed by screw plugs 46 .
- the radial bores of the dead spaces are closed externally by screw plug.
- the volume of the commutation chambers which also encompasses the volume of the blind bores 23 , 27 , 29 , in each case corresponds to at least the displacement volume of one displacer and should not exceed five times the displacement volume of one displacer in order to minimize compression/decompression losses.
- the displacers accommodated in the rotating cylinder drum are in the course of their rotary movement successively connected with the three control kidneys 18 , 20 and 22 and subjected to the corresponding pressure.
- the respective displacer volume is connected through one of the three through bores 23 , 27 and 29 with the associated dead space 40 , 42 or 44 , respectively, so that in practice, the oil volume of the associated displacer chamber is increased by the volume of the dead space. Owing to the resulting smooth shiftitng, the above described strains and noise emissions are reduced considerably, and thus the effectivity of the hydraulic transformer is improved in comparison with conventional solutions.
- First test runs with the hydraulic transformer of the invention confirm its superiority over the known solutions.
- the shape of the cavities inside the base body 24 is of minor importance. What is essential is that the volumes of the dead spaces effective in the commutation zones are dimensioned in accordance with system pressure, switching frequency and geometry of the through bores, such that the rigidity of the “oil spring” is reduced in the commutation phase.
- a hydraulic transformer includes a multiplicity of displacers each guided in a displacer chamber. Pressure medium supply and discharge to and from the displacer chambers is controlled through the intermediary of control means provided with control recesses. The effective position of the control recesses in relation to the dead center positions of the displacers is variable, with each displacer volume being adapted to be connected with a dead space in a commutation phase upon transition between two adjacent control recesses.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Reciprocating Pumps (AREA)
Abstract
Description
- The invention relates to a hydraulic transformer in accordance with the preamble of
claim 1. - A hydraulic transformer is a unit wherein an energy flow Q1×p1 is transformed into an energy flow Q2×p2 through hydraulic coupling of a hydrostatic motor and a pump. In the process, only the amount of hydraulic energy required for driving a consumer that is connected to the pump is withdrawn from an existing pressure supply. Such hydraulic transformers may be designed as radial piston engines, axial piston engines, or in accordance with other kinematic function principles, e.g., as vane-cell machines.
- U.S. Pat. No. 3,188,963 discloses a hydraulic transformer having the form of a swashplate motor, wherein displacers guided in a rotatable cylinder are supported on a stationary swash plate. The angle of the swash plate determines the piston stroke of the displacers. Pressure medium supply and discharge are performed with the aid of a control disc having four control kidneys, wherein the respective pairs of control kidneys are associated with the motor and the pump.
- In U.S. Pat. No. 3,079,864 a hydraulic transformer in vane-cell construction is disclosed. In this solution, a multiplicity of displacers translatable in a radial direction are mounted in a rotor and biased against a cam ring. Pressure medium supply and discharge are performed, similar to the above described solution, with the aid of a control disc arranged on the front end side.
- From WO 97/31185 A1 and from the reference, “Ein neuer alter Bekannter—der Hydrotransformator” [A new old acquaintance: the hydraulic transformer], Siegfried Rotthäuser, Peter Achten; O+P “Öhydraulik and Pneumatik” 42 (1998) No. 6; p. 374 et seq., the so-called INNAS hydraulic transformer is known, wherein the transformation ratio, i.e. the ratio between the supply pressure and the pressure for supplying the consumer, is variable. To this end, a control disc is provided with three control kidneys, the relative position of which to the dead center positions of the displacers is variable by rotation relative to the swash plate of an axial piston machine.
- From DE 100 252 48.6, a further development of the hydraulic transformer disclosed in WO 97/31185 A1 is known. In this solution, the pressure medium ports (supply port, work port, tank port) open in a radial direction into the rotatable control means, so that the forces acting in an axial direction are reduced.
- In hydraulic transformers of this design, the displacer chambers are inherently also shifted outside of the dead center positions, wherein this shifting may take place at arbitrary piston velocities. Shifting takes place within a substantially smaller rotational angle interval in comparison with pumps and motors, so that comparatively high pressure gradients may occur, which may lead to excessively high mechanical strains on the hydraulic transformer and high noise emission.
- Besides these high pressure gradients, particularly pressure adaptation during shifting is very difficult to implement in practice. In the ideal case, the pressure should rise or drop linearly to the subsequent pressure level during the entire rotational angle interval. It was found, however, that such a shifting property cannot be realized across the entire operating range of the transformer. The rigid commutation geometry may lead to cavitations and pressure peaks in the commutation ranges, so that the above described noise emissions and the mechanical strain on the hydraulic transformer are increased further.
- Before this background, the invention is based on the object of providing a hydraulic transformer wherein the load is reduced by pressure gradients in the commutation range.
- This object is achieved through a hydraulic transformer having the features of
claim 1. - In accordance with the invention, the hydraulic transformer is provided with a multiplicity of displacers each guided in a displacer chamber and capable of being connected through commutation means including a pressure port, a consumer port, or a tank port, the relative position of the commutation means being variable relative to the dead center positions of the displacers. In accordance with the invention, the oil volume of the displacer chamber to be shifted is increased during the commutation phase. This is achieved in particular in that in this commutation phase, the respective displacer volume is connected with a commutation chamber. As a result of these increases in the oil volume, the pressure gradients, pressure peaks, and noise emissions are reduced considerably in the commutation phase.
- In a particularly preferred embodiment, the control means include three control recesses distributed at the periphery, with the commutation chambers opening into respective ranges between two adjacent control recesses.
- Here it is particularly preferred if these control recesses have an approximate kidney shape, and the commutation chambers each open into one of the kidney separation webs.
- In a preferred embodiment, the control kidneys and through bores of the commutation chambers are formed in a control disc of the control means.
- In a preferred manner, the commutation means have next to the control disc a base body in which a part of the commutation chamber is formed next to the through bores of the control disc.
- It is particularly advantageous if the volume of each commutation chamber is greater or at least equal to the displacement volume of a displacer.
- The volume of the commutation chamber should, however, preferably be less than five times the displacement volume. This range may, however, vary in accordance with system pressure, switching frequency, and geometry of the control bores.
- The hydraulic transformer of the invention preferably has the form of an axial piston bent-axis unit. As was already mentioned at the outset, the invention may also be applied in other kinematic functional principles for hydraulic transformers.
- Further advantageous developments of the invention are subject matters of the remaining subclaims.
- In the following, a preferred practical example of the invention shall be explained in more detail by referring to schematic drawings, wherein:
-
FIG. 1 is a three-dimensional representation of a hydraulic transformer in bent-axis design; -
FIG. 2 is a front view of a control member of the hydraulic transformer ofFIG. 1 ; -
FIG. 3 is a three-dimensional representation of the control member ofFIG. 2 ; and -
FIG. 4 is a longitudinal sectional view of the control member ofFIGS. 2 and 3 . -
FIG. 1 shows a three-dimensional schematic representation of ahydraulic transformer 1 executed in bent-axis design. In principle, a likehydraulic transformer 1 may be represented as a combination of a hydrostatic motor and a hydraulic pump mechanically coupled to each other. In accordance with the prior art described at the outset, hydraulic transformers may be realized through variable displacer units, with axial piston machines or vane cell machines preferably being used. Fundamentally it is, however, possible to employ any displacer unit where the displacers may be controlled such that they may successively be taken into operative connection with three pressure levels: the supply pressure, the tank pressure, and the consumer pressure (work pressure). - The
hydraulic transformer 1 in accordance withFIG. 1 includes anangled housing 2 in which displacers guided inside a cylinder drum, a drive flange, and a drive shaft are arranged. To the angled housing 2 a control housing 4 is attached which is closed by acap 5. Supply and discharge of the pressure medium to and from the cylinder chambers is effected through acontrol member 12 accommodated in the control housing 4 which may be adjusted to vary the transmission ratio between pump and motor. The commutation means may be adjusted in relation to the dead center positions of the displacers with the aid of adjusting means, such as with the aid of anelectric motor 6 or any other suitable drive mechanism, e.g., a gear drive. - On the
angled housing 2 and on the cap 5 a work port B, a tank port T, and a supply port A are provided. These ports may be executed as axial or radial ports. - The construction of the bent-axis unit including the displacers is sufficiently known from the prior art. In this regard, reference is made, e.g., to patent application DE 100 252 48, so that a detailed description of the bent-axis unit may be omitted.
- The
control member 12 of FIGS. 2 to 4 is rotatably mounted in the control housing 4 and includes at its outer periphery aflange 14 for axial contact with a gear (not shown). By means of this gear it is possible to adjust thecontrol member 12 in relation to the dead center positions of the displacers. Thecontrol member 12 hat on its end-face side (view ofFIG. 2 ) acontrol disc 16 which sealingly contacts the cylinder drum rotatably mounted in theangled housing 2. Inside this cylinder drum, the displacers are guided which are translatable in an axial direction and supported on a bent axis. Threecontrol kidneys control disc 16. Between two respective adjacent control kidneys there remains akidney separation web 25 into which an axialblind bore - As is particularly evident from the three-dimensional representation of the
control member 12 inFIG. 3 , thecontrol disc 16 is part of abase body 24, at the outer periphery of which theflange 14 is formed. In thebase body 24,connection passages control kidneys control kidney 18 is connected via theconnection passage 26 and radially mergingpassages 32 with the tank port T,control kidney 20 is connected via theconnection passage 28 and anoblique passage 36 extending obliquely to theaxis 34 of thecontrol member 12 with the consumer or work port B, andcontrol kidney 22 is connected via threebores 38 extending in parallel with the axis with the supply port A. I.e., depending on their position relative to thecontrol kidneys kidney separation webs 25 is selected such that a displacer volume may be covered by thekidney separation web 25 in the commutation phase between two adjacent control kidneys. In conventional solutions, these kidney separation webs are closed, so that in the commutation phase a complete coverage of the displacer chamber ensues. In accordance with the invention, in the commutation phase the displacer chambers located in the range of thekidney separation webs 25 are connected withdead spaces FIG. 3 via the blind bores 23, 27 and 29. These have the form of axial and radial or oblique bore sections in thebase body 24 and are represented externally of thecontrol member 12 inFIG. 3 for the sake of clarity. The geometries of the above describedconnection passages dead spaces base body 24. In the represented practical example, thedead space 44 is essentially formed by a centrally arranged, axially extending cavity that is connected with the blind bore 29 through a transverse bore. The twocommutation chambers dead space 44 is closed against thecontrol disc 16 by ascrew plug 45. The axially extending bores of the two other dead spaces are introduced into the end face side of thecontrol member 12 facing away from thecontrol disc 16 and are closed by screw plugs 46. Likewise, the radial bores of the dead spaces are closed externally by screw plug. The volume of the commutation chambers, which also encompasses the volume of the blind bores 23, 27, 29, in each case corresponds to at least the displacement volume of one displacer and should not exceed five times the displacement volume of one displacer in order to minimize compression/decompression losses. - The displacers accommodated in the rotating cylinder drum are in the course of their rotary movement successively connected with the three
control kidneys bores dead space - As was already mentioned, the shape of the cavities inside the
base body 24 is of minor importance. What is essential is that the volumes of the dead spaces effective in the commutation zones are dimensioned in accordance with system pressure, switching frequency and geometry of the through bores, such that the rigidity of the “oil spring” is reduced in the commutation phase. - A hydraulic transformer includes a multiplicity of displacers each guided in a displacer chamber. Pressure medium supply and discharge to and from the displacer chambers is controlled through the intermediary of control means provided with control recesses. The effective position of the control recesses in relation to the dead center positions of the displacers is variable, with each displacer volume being adapted to be connected with a dead space in a commutation phase upon transition between two adjacent control recesses.
- List of Reference Symbols
-
- 1 hydraulic transformer
- 2 angled housing
- 4 commutation means
- 6 handle
- 10 control housing
- 12 control member
- 14 flange
- 16 control disc
- 18 control kidneys
- 20 control kidneys
- 22 control kidneys
- 23 through bore
- 24 base body
- 25 kidney separation web
- 26 connection passage
- 27 through bore
- 28 connection passage
- 29 through bore
- 30 connection passage
- 32 passages
- 34 axis
- 36 oblique passage
- 38 bores
- 40 commutation chamber
- 42 commutation chamber
- 44 commutation chamber
- 45 screw plug
- 46 screw plug
Claims (9)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10241979.5 | 2002-09-11 | ||
DE10241979A DE10241979A1 (en) | 2002-09-11 | 2002-09-11 | Hydrotransformer has dead space which enlarges displacement chamber during reversing phase, and switching unit has three control slots distributed around circumference, with dead spaces opening into region between control slots |
PCT/DE2003/001833 WO2004027267A1 (en) | 2002-09-11 | 2003-06-04 | Hydro transformer |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050166751A1 true US20050166751A1 (en) | 2005-08-04 |
Family
ID=31724622
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/516,728 Abandoned US20050166751A1 (en) | 2002-09-11 | 2003-06-04 | Hydro transformer |
Country Status (3)
Country | Link |
---|---|
US (1) | US20050166751A1 (en) |
DE (1) | DE10241979A1 (en) |
WO (1) | WO2004027267A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070074626A1 (en) * | 2005-10-04 | 2007-04-05 | Sam Hydraulik S.P.A. | Distribution system for a hydrostatic piston machine |
US8662277B2 (en) | 2011-12-22 | 2014-03-04 | Fairfield Manufacturing Company, Inc. | Planetary gearbox with integral service brake |
US9429227B2 (en) | 2014-02-19 | 2016-08-30 | Fairfield Manufacturing Company, Inc. | Planetary gearbox with integral service brake |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102012208323A1 (en) | 2011-06-14 | 2012-12-20 | Schaeffler Technologies AG & Co. KG | hydrotransformer |
CN102434504B (en) * | 2011-12-09 | 2014-02-12 | 哈尔滨工业大学 | Hydraulic transformer with axial flow distribution |
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US2847938A (en) * | 1955-12-01 | 1958-08-19 | John T Gondek | Hydraulic pump |
US2892413A (en) * | 1955-10-25 | 1959-06-30 | Sundstrand Machine Tool Co | Anti-hum device |
US3079864A (en) * | 1963-03-05 | Pressure intensifier | ||
US3183847A (en) * | 1961-12-22 | 1965-05-18 | Hydro Kinetics Inc | Variable displacement pump |
US3188963A (en) * | 1962-06-04 | 1965-06-15 | Bendix Corp | Fluid intensifier |
US3289604A (en) * | 1964-09-23 | 1966-12-06 | Gunnar A Wahlmark | Fluid device |
US3362342A (en) * | 1964-06-12 | 1968-01-09 | Dowty Technical Dev Ltd | Hydraulic apparatus |
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DE1233267B (en) * | 1959-08-21 | 1967-01-26 | Citroen Sa | Device for noise reduction in slide-controlled pumps and liquid motors |
DE2104933A1 (en) * | 1971-02-03 | 1972-08-17 | Robert Bosch Gmbh, 7000 Stuttgart | Axial piston machine |
DE2837178C2 (en) * | 1978-08-25 | 1984-04-19 | Aleksandr Konstantinovič Moskva Alekseev | Axial piston pump |
DE10025248A1 (en) * | 2000-05-22 | 2001-11-29 | Mannesmann Rexroth Ag | Hydraulic transformer has at least those channels leading to supply and working connections of housing opening at periphery of control part in approximately radial direction |
-
2002
- 2002-09-11 DE DE10241979A patent/DE10241979A1/en not_active Withdrawn
-
2003
- 2003-06-04 US US10/516,728 patent/US20050166751A1/en not_active Abandoned
- 2003-06-04 WO PCT/DE2003/001833 patent/WO2004027267A1/en active Application Filing
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US3079864A (en) * | 1963-03-05 | Pressure intensifier | ||
US2892413A (en) * | 1955-10-25 | 1959-06-30 | Sundstrand Machine Tool Co | Anti-hum device |
US2847938A (en) * | 1955-12-01 | 1958-08-19 | John T Gondek | Hydraulic pump |
US3183847A (en) * | 1961-12-22 | 1965-05-18 | Hydro Kinetics Inc | Variable displacement pump |
US3188963A (en) * | 1962-06-04 | 1965-06-15 | Bendix Corp | Fluid intensifier |
US3362342A (en) * | 1964-06-12 | 1968-01-09 | Dowty Technical Dev Ltd | Hydraulic apparatus |
US3289604A (en) * | 1964-09-23 | 1966-12-06 | Gunnar A Wahlmark | Fluid device |
US3585901A (en) * | 1969-02-19 | 1971-06-22 | Sundstrand Corp | Hydraulic pump |
US3847057A (en) * | 1971-04-16 | 1974-11-12 | Bosch Gmbh Robert | Precharging arrangement for a hydraulic displacement machine |
US3999466A (en) * | 1973-06-30 | 1976-12-28 | Eckhard Aschke | Hydrostatic pump/motor unit |
US4007663A (en) * | 1974-02-01 | 1977-02-15 | Mitsubishi Kogyo Kabushiki Kaisha | Hydraulic pump of the axial piston type |
US4037521A (en) * | 1975-01-24 | 1977-07-26 | Dowty Hydraulic Units Limited | Noise reduction |
US5247869A (en) * | 1991-09-06 | 1993-09-28 | Voac Hydraulics I Trollhattan Ab | Method and a device for damping flow pulsations in hydrostatic hydraulic machines of the displacement type |
US6116138A (en) * | 1996-02-23 | 2000-09-12 | Innas Free Piston B.V. | Pressure transformer |
US6575076B1 (en) * | 1996-02-23 | 2003-06-10 | Innas Free Piston B.V. | Hydraulic installations |
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Publication number | Priority date | Publication date | Assignee | Title |
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US20070074626A1 (en) * | 2005-10-04 | 2007-04-05 | Sam Hydraulik S.P.A. | Distribution system for a hydrostatic piston machine |
US8662277B2 (en) | 2011-12-22 | 2014-03-04 | Fairfield Manufacturing Company, Inc. | Planetary gearbox with integral service brake |
US9429227B2 (en) | 2014-02-19 | 2016-08-30 | Fairfield Manufacturing Company, Inc. | Planetary gearbox with integral service brake |
Also Published As
Publication number | Publication date |
---|---|
WO2004027267A1 (en) | 2004-04-01 |
DE10241979A1 (en) | 2004-03-18 |
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