US3775981A - Hydrostatic drive unit - Google Patents

Hydrostatic drive unit Download PDF

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Publication number
US3775981A
US3775981A US00222604A US3775981DA US3775981A US 3775981 A US3775981 A US 3775981A US 00222604 A US00222604 A US 00222604A US 3775981D A US3775981D A US 3775981DA US 3775981 A US3775981 A US 3775981A
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Prior art keywords
cylinder block
motor
drive
pump
trunnion
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Expired - Lifetime
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US00222604A
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English (en)
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H Molly
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Hydromatik GmbH
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Individual
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Assigned to HYDROMATIK GMBH,GLOCKERAUSTRASSE 2, 7915 ELCHINGEN 2,W.GERMANY reassignment HYDROMATIK GMBH,GLOCKERAUSTRASSE 2, 7915 ELCHINGEN 2,W.GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MOLLY HANS
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
    • F16H61/431—Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0035—Reciprocating-piston machines or engines with 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
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0044—Component parts, details, e.g. valves, sealings, lubrication
    • F01B3/0064—Machine housing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0076—Connection between cylinder barrel and inclined swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/10—Control of working-fluid admission or discharge peculiar thereto
    • F01B3/103—Control of working-fluid admission or discharge peculiar thereto for machines with rotary cylinder block
    • F01B3/109—Control of working-fluid admission or discharge peculiar thereto for machines with rotary cylinder block by changing the inclination of the axis of the cylinder barrel relative to the swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/38—Control of exclusively fluid gearing
    • F16H61/40—Control of exclusively fluid gearing hydrostatic
    • F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
    • F16H61/427—Motor capacity control by mechanical control means, e.g. by levers or pedals

Definitions

  • a hydrostatic drive unit comprises a pump driven by a prime mover and having constant delivery during normal operation, and at least one variable stroke axial piston-type motor fed by the pump.
  • the intake volume per revolution of the motor is variable by pivoting the cylinder block about an ofi center pivot axis through an angle of more than 30 such that the dead space in the cylinders is kept as small as possible.
  • the intake volume per revolution of the motor at maximum pivot position is a multiple of the delivery volume per revolution of the pump.
  • the cylinder block of 1 References Cited the motor is carried alon b the drive flan e throu h g y g g UNITED STATES PATENTS peripherally arranged teeth in mesh in the region of 3 175 363 3/1965 Molly 60/53 A the Pivot axis and Permitting the p g movement of the cylinder block.
  • the invention relates to a hydrostatic drive unit comprising a pump driven by a drive shaft and at least one axial pistontype motor fed by the pump, said motor driving a driven shaft and which has a drive flange connected to the driven shaft, a cylinder block pivotable with respect to the driven shaft in a pivotable frame as well as axial pistons guided in the cylinder block and in articulated connection with the drive flange through piston rods.
  • the axial piston-type motor is designed as a motor which develops torque on a swash plate, namely the drive flange.
  • the torque produced by the oil pressure originates atthe drive flange, while the cylinder block is only carried along by the friction being overcome either by the piston rods or by an additional drive connection.
  • the stroke variation takes place in such a motor by the cylinder block being pivoted in a pivotable frame with respect to the drive flange, with the drive flange having a fixed position on the driven shaft.
  • axial piston units those in which the pistons are supported through cross-head shoes or the like on pivotable slipping discs.
  • the cylinder blocks are arranged coaxially from pistons and motor and keyed to the drive or driven shaft. In this case the torques are produced at the cylinder blocks (FIG. 1).
  • Such drive units have the advantage of a coma pact construction, however are somewhat larger in size,
  • the pump In the design of a hydrostatic drive unit the pump must, on the one hand, be able, at full pivot, to supply a stream of hydraulic fluid sufficient to give the hydraulic motor the requisite maximum rotational speed. On the other'hand,however, the pump must also be able to yield a high pressure pressur in the regions of the requisite largest transmission, wherein it must be taken into account that with any readjustment of the stroke volto approximately the intake volume of the motor so that with full angle of pivot of the pump, there is a direct transmission of rotational speed. With a return pivoting of the pump, a reduction in rotational speed is achieved, FIG. 2.
  • a hydrostatic drive unit in which both the pump and the axial piston-type motor, which is substantially larger than the pump, are equipped with a pivotable cylinder block (FIG. 4).
  • the control of the transmission ratio also takes place in the normal control operation in the same way as in the drive unit ume the pressure increases with reciprocal magnitudes.
  • drive units which operate with axial piston-type pumps and motors in which the torque as described is developed on the swash plate.
  • the motor is embodied as an axial piston-type motor with a fixed angle between the drive flange and the cylinder block, wherein therefore, the adjustment of the drive unit takes place by pivoting the cylinder block.
  • the adjustable motor must still be kept large, while the pump thanks to the twostep stepping down yields a smaller angular output.
  • FIG. 5 shows the pressure (p) reduction gear ratio (i)- characteristic curve in drive units of the type according to FIG. 11 and FIG. 2.
  • FIG. 6 shows corresponding characteristic curves I and Ill for the two changeover positions of the back gear (FIG. 3) or pivoting positions of the motor (FIG. 4) respectively in the drive units of FIGS. 3 and 4.
  • the resettings from I to II change-over positions, which thus replace the drive unit arrangement from FIG. 3, but here adjustments from the position I toll are carried out in a separate adjustment operation, if the pump has assumed full angles of pivot.
  • the oil pressure in the dashed line extends from the end point of the hyperbola I to the end point of the hyperbola II. Also mixed adjustments at which the pump and the motor are commonly adjusted according to predetermined mathematical relationships, are in use. In this case the oil pressure runs inside the space enclosed between the two byperbolas I and II.
  • the pump illustrated in FIG. 41 is still subjected to a dimensioning by the angular output which indeed as compared with the example shown in FIGS. 1 and 2, has been reduced to half and corresponding to the take-over of the adjustment range through the hydraulic motor.
  • still no satisfactory dimensioning is given to the installation and also sufficient account is not taken of the required control range, since any resetting of the hydraulic motor to a still smaller angle is space-saving, simple and inexpensive and has a good degree of efficiency in the whole range of operation.
  • this problem is solved in that in the normal control operation the adjustment takes place with fixed conveying volume of the pump on the driven side by pivoting the cylinder block, in that the intake volume per rotation of the axial pistontype motor at a maximum pivoting position of the motor is a multiple of the conveying volume per roatation of the pump, and in that the cylinder block of the axial piston-type motor is pivotable about an off-centre axis such that the dead space in the cylinders is kept as small as possible (FIG. 7).
  • the cylinder block of the axial piston-type motor pivotable to an angle of pivot larger than 30.
  • This can particularly advantageously be solved constructively in such a manner that the cylinder block is carried along by the drive flange through peripherally arranged teeth which are designed in such a manner as to permit a pivoting movement between the cylinder block and the drive flange, and are in mesh with each other in the region of the axis of pivot of the cylinder block (FIG. 9).
  • FIG. 1 is a diagrammatic side elevation of a prior art hydrostatic transmission.
  • FIG. 2 is a diagrammatic side elevation of another form of prior art hydrostatic transmission.
  • FIG. 3 is a diagrammatic side elevation of still another form of prior art hydrostatic transmission.
  • FIG. 4 is a diagrammatic side elevation of a fourth form of prior art hydrostatic transmission.
  • FIG. 5 shows the pressure versus drive ratio characteristic of transmissions according to FIGS. 1 and 2.
  • FIG. 6 shows similar characteristics for the transmission of FIG. 4.
  • FIG. 7 is a side elevation, partly in section, of a transmission of the invention.
  • FIG. 8 shows the pressure versus drive ratio characteristic of a transmission of FIG. 7.
  • FIG. 9 is a diagrammatic side elevation of another embodiment of a transmission of the invention.
  • FIG. 10 shows, in section, a first embodiment of a drive unit according to the invention.
  • FIG. 11 is associated plan view with portions broken away.
  • FIG. 12 schematically illustrates a second embodiment having several hydraulic motors fed by a pump.
  • FIG. 13 is a section with portions broken away of a double motor shown in FIG. 12.
  • FIG. 14 shows a section along the line X-X in FIG. 13.
  • FIG. 15 shows a view of the pressure output for the double motor.
  • 10 designates a drive unit housing which is closed on the drive side by a cover part 12.
  • a drive shaft 14 is mounted in bearing in the cover part 12.
  • the drive shaft is dirven by a prime mover, not shown.
  • a filling pump 20, designed as a cycloid pump, is keyed on the drive shaft. This pump draws in oil from a sump 22 through a conduit 24 and discharges it in a chennel 26 which runs centrally in the drive shaft 14.
  • the drive flange 28 of an axial piston pump generally 30 is disposed on the drive shaft.
  • the axial piston pump works in the normal control range with constant pivot position and correspondingly constant qunatity of hydraulic fluid being moved per rotation, but for starting purposes it can be angularly adjusted by an adjusting cylinder 32 through a guide rod 34.
  • the driven shaft 40 On the other side of the housing 10 the driven shaft 40, on which the drive flange 42 of an axial piston-type motor generally 44 is disposed, is mounted in bearings 36 and 38.
  • the ratio of drive rotational speed to driven rotational speed of the drive unit is effected by adjusting the motor 44.
  • the motor 44 is angularly adjusted by an adjusting cylinder
  • the intake volume of the motor 44 in the illustrated, fully pivoted position is a multiple of the discharge volume of the pump. Therefore a relatively large range of driven rotational speeds can be achieved, the angles of pivot of the motor being kept within required limits.
  • the motor is pivoted back to a small angle of pivot not impairing the efficiency, while on the other hand the maximum angle of pivot is determined by the physical characteristics of the machine.
  • the cylinder block 48 is pivotable in a pivotable frame 50 about an off center axis 52 so that the oil volume in the upper dead center of the pistons 54 and 56 can be kept as small as possible in all positions.
  • the dead space of the motor is kept small in a manner known per se by this construction. Also see patent application Ser. No. 199,974, filed Nov. 18,1971.
  • the axial piston pump 30 includes the drive flange 28. Piston rods 58 are articulated to the drive flange 28. The piston rods are also articulated to axial pistons 60 which are guided in a cylinder block 62.
  • the cylinder block 62 bears against a spherical surface of a stationary valve portion 64 held in a pivotable frame 66.
  • the cylinder block 62 is guided on a trunnion 68 which is articulated at a pivot point 70 on the drive flange.
  • the trunnion 68 is hollow and contains a spring 72 which presses the cylinder block 62 against the stationary valve portion 64.
  • the motor includes the drive flange 42 to which the piston rods 74 are articulated.
  • the piston rods are articulated to the pistons 54 which are guided in the cylinder block 48.
  • the cylinder block 48 is mounted in a pivotable frame 50 and abuts a stationary valve portion 76 having a spherical control surface 78.
  • the cylinders in the cylinder block 48 communicate with the stationary valve portion 76 through inclined channels 80 so that a small diameter of the reversing channels results.
  • the cylinderblock 48 is likewise guided on a hollow trunnion 82 which is centrally articulated to the drive flange 42.
  • a compression spring 84 in trunnion 82 presses the cylinder block against the stationary valve portion 76.
  • Oil is fed to the motor by the pump through the adjusting cylinder 46 designed as a telescopic tube,- the piston 86 (FIG. 11) in the adjusting cylinder being designed as a differential piston.
  • the oil pressure pres ent in the adjusting cylinder 46 counteracts the torque which is caused by the oil pressure of the cylinder block 48 as a result of the off-center pivoting positioning of the pivotable frame 50.
  • Pressure oil can be supplied through conduits 88 to the space 90 at the differential steps (FIG.
  • the filling oil from pump 20 is conducted through the conduit 26, a pressure field 94 under the articulated head of the pivotable trunnion 68, a pressure field 95, a channel 98 and a check valve 100 (FIG. 11) to the intake side of the stationary valve portion 64.
  • a power take-off shaft 102 is mounted in the housing '10. By this shaft a direct drive from the prime mover to any operating apparatus assembly can be obtained.
  • the pump 30 normally works at a fixed pivot position of 30/Before starting the pump is at an idling position of and to start is moved from that position to i 30. Thereafter the rotational speed regulation takes place by pivoting the motor 44 which can be pivoted to a maximum pivot position of from 30 to 50, the pivot position of the motor corresponding to the direct drive 1:1.
  • FIG. 12 shows the hydraulic circuit of another embodiment of the invention.
  • a pump generally 104 which is driven by a drive shaft 106.
  • the pump is as can be seen pivotable from a zero position about 30 to both sides. The mean zero position in this case corresponds to idling or stop. It can then be started forwards or backwards until the pump has attained its pivot position of +30 or 30.
  • Oil flows through a conduit 108 to the motor assemblies generally 110, 112, etc.
  • a filling pump 114 supplies filling oil into the system through check valves 116.
  • There is a pressure regulator generally 118 which keeps the oil pressure constant in whichever conduit 108 or 138 is servingas the supply conduit, through a check valve arrangement 120.
  • conduit 108 serves as the supply conduit
  • conduit 138 serves as the return conduit and vice versa.
  • the pressure regulator 118 includes a slide 122 which is by a spring 124 and controls the fluid communication between the supply conduit 108 or 138 and an outlet 126.
  • the force exerted by the spring 124 is adjusted by an control lever 128. The greater the force applied by the spring the greater will be the pres sure in the supply conduit (108 or 138) and the less the force the less the pressure.
  • Each motor assembly includes two motors 130, 132 which are articulated in pivotable frames so as to pivot in an off-center manner.
  • the hydraulic moments acting on the pivotable frames are taken up by the adjusting cylinders 134, 136, by which an adjustment of the angular position of the motor'cylinder'blocks is possible.
  • Conduit 138 leads from the other connection of the pump 104 to'the other connections on motor assemblies 110, 112, etc. When the pump 104 pivotsinto the other position the conduits 3108 and 138 exchange their function.
  • Each of the motors and 132 includes a drive flange 141 and l40'respectively to which are articulatedpiston rods 142.
  • Pistons 144 are disposed on the piston rods 142.
  • the pistons are guided in a cylinder block 146.
  • the cylinder block 146 is rotatably mounted on a trunnion 148 heldiin a pivotable frame 150 and abuts against. a stationary valve portion 152.
  • the concurrent rotation of the cylinder block and the drive flange is effected by-a bevel drive with teeth 154, 156 on-toric surfaces.
  • the toric surfaces in this case, have the centersl58, 160 in the plane of engagement and intersection.
  • Pivoting of the pivotable frame and the cylinderblock 146 is effected about an off-centre axis in the form of a rolling movement of the toric surfaces on each other, that is such that the dead space in the upper dead denter of the cylinder 144 is kept as small as possible.
  • the drive flanges 141,140 of the two motors 130, 132 are mountedwith their hubs 162,163 on ashaft 164. Thesehubs are supportedin an axial direction through a sliding disc 166 thatteat' the axial components, acting againsteach other, of the hydraulic forces acting on the drive flanges 140, 141 can be absorbed at the sliding disc.
  • the dotted lines 168, 169 indicate the transmission of this axis thrust.
  • the dotted lines 170, 171 show how the residual thrust is conducted to the housing.
  • Teeth172 and 173 on the hubs 162 and 163 respectively are in mesh with gears174 and 175.
  • Gears 174 and 175 are each disposed on a half shaft 176 and 177 respectively which are each'in drive connection with a drive wheel of a pair of drive wheels.
  • FIG. l4 which illustrates a section along the lines X-X of FIG. 13, shows how the'pivotable frames 150 are mounted on the housing and how this bearing support' is utilized for the oil supply.
  • a connecting side bar 178 has two side-by-side bores in which'are bearing trunnions 180 and 182. Trunnion 180 is secured to the housing and trunnion 182 is secured to the pivotable frame. Pressure fields are limited by annular rings 184 and 186or l88and respectively seated in grooves on the outer surface of the bearing trunnions.
  • the annular rings 184 and 186 or 188 and 190 respectively are positioned in oppositely inclined planes inthe trunnion axes, so thatin each case pressure fields enlarging outwards toone side results. These pressure fields relieve the bearing from the hydraulic forces acting thereon at the pivoting frame.
  • the pressure fields on the outer surface of the trunnions 180 and 182 are interconnected'through a channel 192 inthe connecting side bar 178.
  • Anoil feed channel 194 inthe trunnion 189 is connected to the pressure side of the motor 130 or 132 respectively through the channel 192 and through a conduit 196 in the trunnion 182.
  • FIG. shows the composition of the pressure conduit of the motors 130, 132.
  • the pressure oil entering in the connection 210 is, in this case, conducted through the two openings 208 into the channels 194 (FIG. 14).
  • the adjusting cylinders 134, 136 are so arranged that the force effective therein during the return of the motors 1'30, 132 decreases their spacing to the ideal pivot point 156, 158, 160 so that the adjusting pressure increasing in the adjusting cylinders 134, 136 forces a pivoting of the same magnitude of the motors 130, 132 and so on.
  • a hydrostatic drive unit comprising a driven shaft, a drive shaft, a rotary hydraulic pump connected to the drive shaft and producing an output of a given volume of hydraulic fluid per revolution, at least one axial piston-type motor communicating with the pump to be supplied with hydraulic fluid from the pump, said motor including a cylinder block, pistons in said cylinder block, a drive flange rotatable about an axis, piston rods connecting the pistons and the drive flange, and means supporting the cylinder block for rotation and for pivotal movement about a pivotal axis whereby the hydraulic fluid intake volume of the motor is varied by changing the pivotal position of the cylinder block, there being a dead space in the cylinders when the pistons are fully seated therein, means connecting the drive flange to the driven shaft, the improvement comprising:
  • said pump producing said volume with speed variation being accomplished by pivoting said cylinder block of the motor, said means supporting said cylinder block establishing a maximum angle of pivot of the cylinder block at which the intake volume of the motor is a multiple of said given volume of the pump, said pivotal axis being offset from said rotational axis so that the dead space in the cylinders is kept as small as possible.
  • a hydrostatic drive unit characterized in that the cylinder block of the axial piston-type motor is pivotable up to an angle of pivot of greater than 30.
  • a hydrostatic drive unit as set forth in claim 3 including a housing, wherein the cylinder block and the drive flange have toric surfaces on which said teeth are mounted, said means supporting the cylinder block includes aframe, a bearing trunnion on the side of the housing, a bearing trunnion on the side of the frame and a connecting side bar having bores within which said trunnions are received, and including angle bisecting gearing means interconnecting the housing and the frame.
  • a hydrostatic drive unit as set forth in claim 4 including a hydraulic fluid conduit between the pump and the motor, characterized by part of said conduit extending through said trunnions and through a channel in the connecting side bar between said bores therein, said trunnions having annular rings thereon at each side of said channel with said rings defining pressure fields about the trunnions.
  • each trunnion is formed about an axis and the respective rings are in planes inclined in opposite directions with respect to the respective trunnion axis so that the pressure field of a trunnion is larger at one side of the trunnion axis than at the other side, and other side being adjacent the other trunnion.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Hydraulic Motors (AREA)
  • Reciprocating Pumps (AREA)
US00222604A 1971-02-04 1972-02-01 Hydrostatic drive unit Expired - Lifetime US3775981A (en)

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DE19712105119 DE2105119B2 (de) 1971-02-04 1971-02-04 Hydrostatisches getriebe

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864916A (en) * 1972-09-25 1975-02-11 Renault Hydrostatic transmissions for motor vehicles
US5033358A (en) * 1988-01-04 1991-07-23 Hans Molly Axial piston type motor
US20040251067A1 (en) * 2000-01-10 2004-12-16 Government Of The U.S.A As Represented By The Adm. Of The U.S. Environmental Protection Agency Hydraulic hybrid vehicle with integrated hydraulic drive module and four-wheel-drive, and method of operation thereof
US20050207921A1 (en) * 2000-01-10 2005-09-22 Gov't of the U.S.A. as represented by the Adm. of the U.S. Environmental Protection Agency Opposing pump/motors
WO2006042435A1 (de) * 2004-10-20 2006-04-27 Markus Liebherr International Ag Hydrostatische axialkolbenmaschine sowie verwendung einer solchen maschine
US7392654B1 (en) * 2004-02-27 2008-07-01 Hydro-Gear Limited Partnership Zero turn drive apparatus
US20080314039A1 (en) * 2000-01-10 2008-12-25 Gov Of The U.S.A, As Rep By The Admn Of The U.S. Environmental Protection Agency Hydraulic hybrid vehicle with integrated hydraulic drive module and four-wheel-drive, and method of operation thereof
US20120227393A1 (en) * 2011-03-10 2012-09-13 Gray Jr Charles L Modular Hydraulic Hybrid Drivetrain
US8733091B1 (en) 2007-08-01 2014-05-27 Hydro-Gear Limited Partnership Pump and engine configuration
US9010105B1 (en) 2007-08-01 2015-04-21 Hydro-Gear Limited Partnership Transmission and engine configuration
US20150377350A1 (en) * 2014-06-27 2015-12-31 Claas Industrietechnik Gmbh Transmission arrangement
US9726269B1 (en) 2009-07-24 2017-08-08 Hydro-Gear Limited Partnership Transmission and engine configuration
US10550934B2 (en) * 2017-02-14 2020-02-04 Robert Bosch Gmbh Hydrostatic transmission and method for braking using the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014211664A1 (de) * 2014-06-18 2015-12-24 Zf Friedrichshafen Ag Anordnung mit mehreren Axialkolbenmaschinen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175363A (en) * 1961-04-20 1965-03-30 Hans Molly Hydraulic machine of axial piston type

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175363A (en) * 1961-04-20 1965-03-30 Hans Molly Hydraulic machine of axial piston type

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864916A (en) * 1972-09-25 1975-02-11 Renault Hydrostatic transmissions for motor vehicles
US5033358A (en) * 1988-01-04 1991-07-23 Hans Molly Axial piston type motor
US5094146A (en) * 1988-01-04 1992-03-10 Hans Molly Axial piston type motor
US7337869B2 (en) 2000-01-10 2008-03-04 The United States Of America As Represented By The Administrator Of The United States Environmental Protection Agency Hydraulic hybrid vehicle with integrated hydraulic drive module and four-wheel-drive, and method of operation thereof
US20050207921A1 (en) * 2000-01-10 2005-09-22 Gov't of the U.S.A. as represented by the Adm. of the U.S. Environmental Protection Agency Opposing pump/motors
US8162094B2 (en) 2000-01-10 2012-04-24 The United States Of America, As Represented By The Administrator Of The U.S. Environmental Protection Agency Hydraulic hybrid vehicle with large-ratio shift transmission and method of operation thereof
US20110232418A1 (en) * 2000-01-10 2011-09-29 Government Of The United States Of America, As Represented By The Administrator Of The U.S. Epa Hydraulic hybrid vehicle with large-ratio shift transmission and method of operation thereof
US20070278027A1 (en) * 2000-01-10 2007-12-06 Government Of Usa, As Represented By The Administ. Of The U.S. Environmental Protection Agency Hydraulic hybrid vehicle with integrated hydraulic drive module and four-wheel-drive, and method of operation thereof
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Also Published As

Publication number Publication date
DE2105119A1 (de) 1972-08-10
DE2105119B2 (de) 1972-12-21
GB1334198A (en) 1973-10-17

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