US3618472A - Device for adjusting the stroke volume in a swash plate axial piston motor or pump - Google Patents

Device for adjusting the stroke volume in a swash plate axial piston motor or pump Download PDF

Info

Publication number
US3618472A
US3618472A US9641A US3618472DA US3618472A US 3618472 A US3618472 A US 3618472A US 9641 A US9641 A US 9641A US 3618472D A US3618472D A US 3618472DA US 3618472 A US3618472 A US 3618472A
Authority
US
United States
Prior art keywords
control
swash plate
piston
lever
plunger
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.)
Expired - Lifetime
Application number
US9641A
Other languages
English (en)
Inventor
Hans Knaak
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mannesmann Meer AG
Original Assignee
Mannesmann Meer AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from DE19691908234 external-priority patent/DE1908234C3/de
Priority claimed from DE19691961908 external-priority patent/DE1961908C3/de
Application filed by Mannesmann Meer AG filed Critical Mannesmann Meer AG
Application granted granted Critical
Publication of US3618472A publication Critical patent/US3618472A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • F04B1/26—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
    • F04B1/324—Control of machines or pumps with rotary cylinder blocks by varying the relative positions of a swash plate and a cylinder block by changing the inclination of the swash plate

Definitions

  • the present invention relates to control device for infinite adjustment of the stroke volume of swash plate fluid motors or pumps with axially operating pistons.
  • the invention relates particularly to improvements in arrange ments of a control piston, of feedback servo valve, of a swash plate tilt angle adjuster, and of linkage between them as well as for the swash plate.
  • a control piston linked to the swash plate and position controlled by a servo valve, as the valve controls fluid passage to and from the piston chamber or cylinder of the control piston, in dependence upon position of a control plunger.
  • the plunger is linked to the swash plate by means of a single control lever to obtain feedback which lever can pivotally move as if supported by an actual spherical bearing due to pivotability of the lever about an axis transverse to the axis of the control plunger in relation thereto and further due to the ability of the control plunger to turn in its valve chamber.
  • an adjusting lever can be provided and articulated to the control lever, or an axially displaceable control rod can be provided on which is journalled an axially fixed connector which, in turn, is linked directly to the control lever by a ball and socket like joint.
  • swash plate adjustment is initiated by a turning motion
  • swash plate adjustment is initiated by a linear motion in the system to be transmitted upon the control lever.
  • the axial position of the connector on the control rod is fixed by a holding disk screwed to the connector, and having a collar sandwiched between them.
  • the collar pertains to the control rod and defines relative axial position of the connector on the control rod.
  • the precise axial position of the connector on the rod results from placement of suitable washers in relation to collar and connector.
  • the three-dimensional movement of the control lever is taken up by the pivot point in a ball-and-socket joint, the socket thereof together with the ball being disposed to permit displacement thereof in a fork and pertaining to the adjustment lever.
  • the fork retains the pivot point established by the ball-and-socket joint.
  • FIG. 1 is a section view into a swash plate, axial piston fluid motor or pump improved in accordance with the invention
  • FIG. 2 is a section view along lines I I of FIG. 1, showing details of a first embodiment of the invention
  • FIG. 3 is a vertical section along lines II-II in FIG. 2, and
  • FIG. 4 can be regarded as a corresponding section view along lines II in FIG. 1 but showing a modified construction as to that section.
  • a housing 24 journalling a shaft 25 and including parallel operating pistons 27 which r ciprocate in cylinder barrels such as 26.
  • a swash plate or tilting plate 1 is mounted on the shaft for rotation therewith. This fluid device can operate as pump or as motor.
  • the tilting angle of swash plate 1 is adjusted by means of a control piston 2 displaceably disposed in a control cylinder or piston chamber 17.
  • a piston rod 3 connects plate 1 to piston 2. Adjustment of the tilting angle serves for the adjustment of the stroke volume or piston displacement volume in the axial piston fluid motor or pump.
  • control piston 2 is constructed as differential piston, A relatively small annular surface 4 of control piston 2 is permanently subjected to a particular hydrostatic pressure. The relatively large circular surface 5 on the other side of the piston is selectively subjected to the same pressure or is relieved upon depressurizing chamber 17. The position of piston 2 is determined at any instant by the balance of pressure forces acting on opposite ends of the piston and adjusting same.
  • piston rod 3 In order to avoid dangerous transverse forces and in order to avoid tipping or undesired tilting of piston 2 the permissible angular deflection of piston rod 3 is maintained rather small. This feature is obtained by selecting a correspondingly large distance between bearing and support points of piston rod 3 on tilting plate 1 and in control piston 2, respectively.
  • the connection and pivot point of piston rod 3 in control piston 2 is located in the range of piston guidance in the cylinder or chamber 17 (see particularly FIG. 2).
  • Swash plate 1 is tilted about pivot axis S by means of adjustment of control piston 2.
  • the pivot and linking point and axis at the connection of swash plate 1 and rod 3 describes an arc on which there are shown three points, A, B and C, in representation of particular adjusting positions.
  • Point A denotes the position of the connecting point for adjusting the axial piston-cylinder arrangement (27, 26) of the fluid pump or motor for maximum stroke volme.
  • the rod-swash plate linking point is tilted to assume position B, and here the stroke volume of the pump or motor is zero, as in this position plate 1 is transverse, at right angles, to the axis of shaft 25. Further retracting of the control piston leads to position C corresponding to a phase shift by 180 of swash plate operation because inlet and outlet sides of the axial piston unit have been interchanged. In position C there is again maximum stroke volume for this mode of operation.
  • FIGS. 2 and 3 pertain to the same embodiment.
  • FIG. 2 illustrates in particular a section view wherein the section plane coincides with the plane of operation of the control piston and of the servo valves.
  • the linking point of piston rod and swash plate 1 can be tilted out of that plane.
  • Control fluid is provided through a channel 6 for control of the position of piston 2. That control fluid may be taken from the main fluid circuit or from the control circuit or any other suitable source or reservoir of pressurized fluid.
  • the control fluid is fed from channel 6 to a ring channel 7 to act on piston face 4.
  • a duct 8 leads from ring channel 7 to a ring channel 9 of a servo valve. Ring channel 9 is, thus, under pressure of the control fluid.
  • a second ring channel 10 is connected through a duct 11 to a venting outlet leading to the tank, i.e., the interior of housing 24 or to any other return path for the control fluid at zero pressure. Further fluid conduction is under control of the servo valve linking these ducts and channels with piston chamber 17.
  • a ring chamber 19 may selectively be connected to channel 10 leading to the venting outlet, or chamber 19 may be connected to pressurized ring channel 9.
  • Ring channel 19 is connected to piston chamber 17 via a duct 18. The selectivity of this connection depends on the position of a plunger 15.
  • Swash plate 1 is connected to the control plunger of the servo valve by means of a single control lever 12.
  • a roll joint 21 establishes articulation between plunger 15 and lever 12.
  • An adjusting lever 23 is connected to lever 12 by a ball and socket joint estabishing pivot point D (see FIG. 3).
  • lever 23 can be pivotally adjusted by suitable handle or control knob means, whereby a fork end of the lever 23 turns in a plane transverse to the plane of FIG. 3 and on an axis transverse to the plane of FIG. 2.
  • E FIG.
  • control plunger 15 of the servo valve is shifted correspondingly to the right. This is true because the center of a slidably positioned ball of a ball and socket joint 13 serves as fixed reference point for pivoting.
  • the ball of joint 13 pertains to a pin 14 as part of the linkage between swash plate 1 and lever 12.
  • control plunger 15 moves to the right its control edge passes the control edge 16 of the valve cylinder establishing communication between ring chambers 10 and 19, so that the cylinder and piston chamber 17 of the control piston (2)-cylinder arrangement is vented through outlet duct 11.
  • the conduit path for venting runs particularly from chamber 17 via duct 18, ring channel 19 as now connected to ring channel 10, and from there to venting duct 11.
  • chamber 17 depressurizes, and now the previously too low pressure force acting on annulus 4 of control piston 2 prevails and suffices to shift piston 2 to the right.
  • the swash plate 1 is shifted in direction of point B (see FIG. 1).
  • the center of the ball of ball and socket joint 13 is shifted to the right (FIG. 2).
  • the pivot point D acts as fixed point so that double arm lever 12 pulls control plunger 15 of the servo valve to the left and back into its initial position.
  • control piston 15 is shifted to the left at first. Thereupon the control edge 20 of the valve chamber is opened. Now a flow path for pressurized control fluid is established, running from ring channel 9 across edge 20, ring channel 19, duct 18 to cylinder chamber 17 of the principle control piston 2. Hence, chamber 17 will be pressurized. As circular area 5 is about twice as large as annulus 4, pressure force on piston surface 5 soon prevails and shifts control piston 2 to the left. Accordingly, the swash plate 1 is tilted to move towards point A. By analogous feed back operation control piston 15 is shifted back to the right until closing control edge 20 (or until the piston 2 has assumed terminal position which limits the tilting angle of swash plate 1).
  • ball and socket joint 13 is provided with a socket bore 22 for the ball.
  • the ball on pin 14 can thus move back and forth in bore 22 of control lever 12.
  • control lever 12 is linked to control piston 15 by means of roll joint 21 having fixed pivot point and axis in relation to both elements 12 and 15.
  • the pivot axis in joint '21 is transverse to the axis of plunger 15.
  • lever 12 undergoes a threedimensional motion which must be taken up by a spherical type bearing, so as to avoid locking.
  • the spherical bearing is established in accordance with a feature of the invention, by permitting concurrent pivoting of control lever 12 about the longitudinal axis of bearing 21 as well as rotation of control plunger 15 in its cylinder about its axis.
  • the ball and socket joint linking levers 23 and 12 is slidably disposed in the fork of lever 23, the threedimensional motion of lever 12 is taken up by that linking point.
  • FIG. 4 there is illustrated a second example for the swash plate tilting control, using also a servo valve controlling a piston drive and being by itself controlled by a plunger 15.
  • the pressurized fluid required for operation of control piston 2 is fed into duct 6 to be passed on to ring channel 9 of the servo valve via duct 8.
  • Ring channel 10 of the servo valve connects to the Zero pressure venting and discharge outlet of the system via duct 11.
  • the control plunger 15 is connected to control lever 12 by means of a fork 47 and by the roll joint 21.
  • One end of lever 12 is connected to swash plate 1 by means of ball and socket joint 13 comprised of a ball on pin 14 which ball can turn and slide in socket 22 of lever '12.
  • the other end of lever 12 is connected to a connecting piece or connector 29 by means of a ball and socket joint 48.
  • the ball of that joint has a bore slidably receiving an end pin 28 of lever 12.
  • Connector 29 is journalled on a control rod 30 so that the connector can pivot about the longitudinal axis of the rod.
  • the axial position of connector 2 9 on rod 30, in longitudinal direction thereon, is a fixed one.
  • control rod 30 is provided with a collar 31.
  • One axial side of collar 31 faces the connector, while on the other side of the collar there is a holding disk 32.
  • Disk 32 is connected to connector 29 by means of bolts 33, and a washer 34 is interposed to determine the precise axial distance between connector 29 and disk 32.
  • the thickness of washer 34 is selected in accordance with the thickness of the sandwiched collar 31 so that the collar 31 can rotate within the space between elements 29 and 32 at minimum axial play.
  • the control rod 30 is axially displaced by forces acting against the force of a spring 35.
  • Pressurized fluid (control pressure) is fed either into a cylinder chamber 37 via a duct 36 to act on the front face of rod 30 or into a cylinder chamber 39 via a duct 38.
  • Chamber 39 contains also the spring 35.
  • control rod 30 serves as piston upon which may act hydrostatic control pressure. Any particular pressure within a particular range produces a force capable of balancing spring 35 at a particular degree of spring compression.
  • Control rod 30 has a central position if the two chambers 37 and 39 are both pressure relieved. In the central position of rod 30 spring disk 40 bears against cylinder end face 41, while a second spring disk 42 bears against the front face of an adjustment or trimmer ring 43.
  • the displacement of the con; trol rod operates as adjustment of the tilting angle of swash plate 1 in the illustrated poition of control rod 30 the swash plate has a tilting angle corresponding to maximum piston displacement and stroke volume of the pistons 27 in cylinders 26 of the pump or motor.
  • the housing of the axial piston is denoted with 24, journalling drive or driven shaft 25.
  • the center M of ball-and-socket joint 48 is likewise displaced to the left, in direction G.
  • the center of ball-and-socket joint 13 is a fixed pivot point at that time, so that the control plunger 15 of the servo valve is shifted also to the left. Now the control edge of plunger 15 passes over control edge 44 of valve chamber 19 and opens a passage between ring channels 19 and 10.
  • Cylinder chamber 17 is vented via duct 18, chamber 19, channel and duct 11. As the hydrostatic pressure in chamber 17 collapses, the force acting on relatively smaller annulus 4 prevails over any residual force on surface 5, and control piston 2 is shifted to the right. As a consequence, swash plate 1 is tilted to move towards point B. Concurrently, the center of ball-and-socket joint 13 is shifted to the right. The center M of ball-and-socket joint 48 defines a fixed pivot point here so that control plunger of the servo valve is returned to its initial position.
  • control plunger 15 is likewise shifted to the right to open passage through control edge 45 between ring channels 9 and 19. Accordingly, the pressure fluid fed to channel 9 (via 6), is conducted through channel 19 and duct 18 into chamber 17, so that full hydrostatic control pressure can build up therein.
  • doubly acting spring 35 places control rod 30 in central position whenever the two chambers 37 and 39 are depressurized. This position must correspond to a stroke valve zero of the axial piston arrangement of this swash plate motor or pump. Accordingly, swash plate 1 must be adjusted to central position (B) at tilting angle zero for this control position of rod 30.
  • central position control plunger 15 and fork 47 are provided with threading 46 to obtain relative positive adjustment between them. This may be a self-locking thread to prevent unintended position change.
  • pin 14 and, therefore, ball-and-socket joint 13 outlines a circle about tilting axis G.
  • the resulting three-dimensional motion of the control lever 12 is taken up by a spherical bearing.
  • Special bearing support is established by permitting concurring pivoting of lever 12 about the longitudinal axis of roll joint 21 and by permitting control plunger 15 to turn in the valve chamber.
  • As the three-dimensional motion of lever 12 is also operative as longitudinal displacement between lever 12 and the pivot point 48, it is also necessary to permit such axial displacement as between lever end 28 and the ball of joint 48.
  • connector 29 can pivot about the longitudinal axis of rod 30, thus, compensating three-dimensional lever movement in cooperation and the universal joint like adjustment of ball-andsocket joint 48.
  • the length compensation as between connector 29 and lever 12 results from shifting of lever end 28 in the ball of joint 48.
  • the connector turns in a plane transverse to the plane of tilting motion, the latter plane being transverse to axis S. This way, the compensatory turning of connector has practically no influence on the tilting.
  • control lever articulated to the swash plate and connected to the plunger by means permitting pivoting of the control lever relative to the plunger about an axis transverse to said first axis, the plunger disposed for rotation about its own axis;
  • adjusting means linked to the control lever for pivoting the control lever about its point of articulation to the swash plate for changing the position of the plunger to obtain valve operation, and establishing a pivot point for the control lever upon resulting piston displacement whereby the plunger is returned to its previous position concurring with turning about its axis and change in angle relation to the control lever.
  • a device for infinite adjustment of the stroke volume in a pressure fluid, swash plate, axial piston motor or pump comprising:
  • a piston-cylinder arrangement the piston thereof connected to the swash plate for adjusting the tilting angle thereof in dependence upon the relative position of the piston;
  • a servo valve including a plunger, the servo valve controlling the fluid in the piston-cylinder arrangement
  • control lever for directly conecting the plunger to the swash plate for providing stabilizing feed back
  • a roll joint pivotally linking the plunger to the control lever, for pivoting about an axis transverse to the axis of the plunger, the plunger permitted to turn in the servo valve chamber about its axis to obtain spherical bearing support for the lever; and adjusting means connected to the control lever to determine an initial position of the plunger for initiating adjusting of the swash plate tilt angle by the piston as controlled by the servo valve.
  • the adjusting means coupled to the control lever for pivoting the control lever about a pivot point established by pivotally linking the swash plate to the control lever, and including means establishing a particular pivot point for the control lever upon change of the relative position of the piston, said established pivot point relatively movable to the axis of the roll joint transverse thereto upon pivoting of the control lever about said established pivot point.
  • control lever articulated to the swash plate by a ball and socket joint, the socket thereof permitting lateral displacement of the ball in a direction having an angle to the tilting plane of the swash plate.
  • the adjusting means including an adjusting lever articulated to the control lever.
  • Device as in claim 6, there being a ball-and-socket joint for articulating the control lever to the adjusting lever and establishing a pivot point slidably disposed on the adjusting lever, for taking up three dimensional movement of the control lever upon change of tilting angle by operation of the control piston.
  • the adjusting lever being a turning fork receiving and slidably positioning a ball and socket joint, the control lever connected to the ball thereof.
  • the adjusting means including an axially movable control rod
  • the inhibiting means including a collar on the rod, a holding disk secured to the connector, the collar being disposed between the connector and the disk, there being at least one distance defining washer in between the connector and the disk.
  • the ball of said joint having an aperture slidably receiving one end of the control lever for articulatedly linking the lever to the connector.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
US9641A 1969-02-14 1970-02-09 Device for adjusting the stroke volume in a swash plate axial piston motor or pump Expired - Lifetime US3618472A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19691908234 DE1908234C3 (de) 1969-02-14 Hebelgestänge zum stufenlosen Einstellen des Hubvolumens von Druckflüssigkeits-Axialkolbenpumpen und -motoren
DE19691961908 DE1961908C3 (de) 1969-12-05 1969-12-05 Einrichtung zum stufenlosen Einstellen des Hubvolumens bei Druckflüssigkeits-Schrägscheiben- Axialkolbenpumpen oder -motoren

Publications (1)

Publication Number Publication Date
US3618472A true US3618472A (en) 1971-11-09

Family

ID=25757021

Family Applications (1)

Application Number Title Priority Date Filing Date
US9641A Expired - Lifetime US3618472A (en) 1969-02-14 1970-02-09 Device for adjusting the stroke volume in a swash plate axial piston motor or pump

Country Status (5)

Country Link
US (1) US3618472A (de)
AT (1) AT294584B (de)
CH (1) CH505988A (de)
FR (1) FR2032880A5 (de)
SE (2) SE383020B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090199554A1 (en) * 2006-06-12 2009-08-13 Yanmar Co., Ltd Hydraulic Stepless Transmission
CN101484727B (zh) * 2006-06-12 2012-12-19 洋马株式会社 液压式无级变速装置
US20220381232A1 (en) * 2021-05-26 2022-12-01 Danfoss Power Solutions Gmbh & Co. Ohg Neutral setting device of an adjustable hydraulic unit

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090199554A1 (en) * 2006-06-12 2009-08-13 Yanmar Co., Ltd Hydraulic Stepless Transmission
EP2050984A4 (de) * 2006-06-12 2011-01-12 Yanmar Co Ltd Stufenloses hydraulikgetriebe
US8302525B2 (en) * 2006-06-12 2012-11-06 Yanmar Co., Ltd. Hydraulic stepless transmission
CN101484727B (zh) * 2006-06-12 2012-12-19 洋马株式会社 液压式无级变速装置
US20220381232A1 (en) * 2021-05-26 2022-12-01 Danfoss Power Solutions Gmbh & Co. Ohg Neutral setting device of an adjustable hydraulic unit
US11933283B2 (en) * 2021-05-26 2024-03-19 Danfoss Power Solutions Gmbh & Co. Ohg Neutral setting device of an adjustable hydraulic unit
US20240218861A1 (en) * 2021-05-26 2024-07-04 Danfoss Power Solutions Gmbh & Co. Ohg Neutral setting device of an adjustable hydraulic unit
US12398709B2 (en) * 2021-05-26 2025-08-26 Danfoss Power Solutions Gmbh & Co. Ohg Neutral setting device of an adjustable hydraulic unit

Also Published As

Publication number Publication date
FR2032880A5 (de) 1970-11-27
AT294584B (de) 1971-11-25
CH505988A (de) 1971-04-15
SE366802B (de) 1974-05-06
SE383020B (sv) 1976-02-23

Similar Documents

Publication Publication Date Title
US5226349A (en) Variable displacement hydrostatic pump and improved gain control thereof
US4028004A (en) Feathering controllable pitch propeller
US3733963A (en) Method and apparatus for controlling displacement of a variable volume pump or motor
US3803987A (en) Servoactuated hydraulic transducer apparatus
US6443706B1 (en) Hydrostatic axial piston machine with electro-hydraulic swash plate control
US3911792A (en) Control system for an axial piston machine
US5722297A (en) Actuator system for gear shifting mechanisms of motor vehicles
US6030182A (en) Variable displacement pump and optional manual or remote control system therefor
US4026195A (en) Axial piston machine of adjustable stroke
US2931443A (en) Pitch control means for variable pitch propellers
US3750532A (en) Servoactuator with mechanical feedback
US3830594A (en) Variable displacement pump having pressure compensator control method
US5957028A (en) Actuator for gear shifting mechanisms for motor vehicles
US3127745A (en) Hydrostatic transmission
US3618472A (en) Device for adjusting the stroke volume in a swash plate axial piston motor or pump
US3750406A (en) Servo-control device for varying the delivery and direction of distribution of a variable delivery pump
US4212164A (en) Variable delivery pump control system
US3700356A (en) Fluid system
US3488955A (en) Hydrostatic transmission drive pump swash plate control
US5108267A (en) Dual-mode control for hydrostatic transmission
US4194361A (en) Electro-mechanical control system for hydraulic displacement pumps, such as swash plate or eccenter pumps
US3545881A (en) Controllable pitch propeller with hydraulic power supply and control
US4168653A (en) Two position variable displacement motor
US3913449A (en) Position-responsive hydraulic cylinder
US3589837A (en) Hydraulic apparatus