US3595019A - Method and apparatus for the synchronized control of two hydraulic drives - Google Patents

Method and apparatus for the synchronized control of two hydraulic drives Download PDF

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Publication number
US3595019A
US3595019A US859888A US3595019DA US3595019A US 3595019 A US3595019 A US 3595019A US 859888 A US859888 A US 859888A US 3595019D A US3595019D A US 3595019DA US 3595019 A US3595019 A US 3595019A
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drives
control
hydraulic
drive
pipeline
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US859888A
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Heinz-Gunter Ehluss
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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
    • F16H43/00—Other fluid gearing, e.g. with oscillating input or output

Definitions

  • the invention relates to a method and an apparatus for the synchronized control of two hydraulic drives with reversing, rotary or rectilinear motion in relation to one another in the same or opposite direction.
  • the two drives are separated in space, the motion characteristic of one of the drives can be controlled either by a follower control or by hand.
  • the drives e.g. hydraulic cylinder or torsional drives are connected in parallel or in tandem and supplied, for example, with oil under pres sure. Because, there can never be the same conditions prevailing at both consumer points with regard to leakage of pressure oil at the seals and to differences in loading, it is necessary to employ a supplementary synchronizing device to equalize the drive point not constituting a return control circuit with the pump unit, with the first operated drive point. Care has to be taken that the technical expenditure on synchronizing systems does not reach that for the possible equipping of the second drive point with its own pump unit and its own follower control.
  • double-flow pumps or volume dividers are used, for example in driving two parallel-running cylinders, and the parallel running is guaranteed by mechanical motion comparison and automatic release of pressure oil on the side which is operating faster at any given time. There is no precise control of the velocity of the cylinder movement however.
  • Mechanical transmission means are only suitable if the two drives are a short distance apart and in most cases they require a definite arrangement of the units to be connected in relation to one another. Furthermore, on account of energy conversion and amplification with auxiliary energy, for example electrical transmission, it is not advantageous from the expenditure point of view.
  • a method of synchronized control for two reversible hydraulic drives with a single hydraulic feed pump which is provided with a follower control which affects the movement of one of the two drives, and in which the pump and the hydraulic drives are connected in series is characterized by a hydraulic control system through which, in the event of lack of synchronism between the two drives, the motion of the drives generates pressure pulses by means of which, when a definite and adjustable pressure value is exceeded in the communication path between the two drives, an amount of fluid corresponding to the error in synchronism is fed in or drained off.
  • the middle positions of one drive and the other are used as the starting point for the generation of'pressure pulses.
  • each one of the drives can move a control piston in each direction of movement, whereby the drive which is not controlled displaces into a connecting pipeline a quantity of a hydraulic medium which is under initial pressure, while the control piston of the controlled drive takes up a quantity ofa hydraulic medium from the pipeline.
  • the method according to the invention can be put into practice by a technical construction of the invention in such a way that if a pressure level, which'is conveniently adjustable, in the pipeline is exceeded a replenishing valve or a draining valve is operated which, depending on the direction of the error (leading or lagging of the noncontrolled drive), increases the volume of hydraulic fluid enclosed between the two drives from the pump pressure line, or reduces it by drainage.
  • the volume equalizing process can take place for each direction of movement of the drive from the midway positions of an oscillatory movement and during the return movement of the control piston to the midway position an exchange of the hydraulic fluid takes place by drainage from a chamber, e.g.' by way of an overflow valve.
  • the invention is directed, furthermore, to apparatus for carrying out the method, especially for torsional movements about a central axis, in which two groups of control pistons can be driven mechanically in each case by one of the hydraulic drives and on the shaft of each of the drives there is a control arm provided, which is connected with an adjusting pin, also a stop, in which arrangement after each passage of the control arm, one of the pistons of the group of control pistons remains stationary and the second is carried along.
  • the synchronization control system is accordingly so designed that each of the two hydraulic drives, on its reciprocating travel, entrains two small. operating pistons. On passing through the midposition towards one side one piston in each case is thereby carried along with the travel of the drive and on returning to the middle is stopped again, whereupon the second piston is carried from the middle to the other side.
  • An oil chamber of the piston of each drive is connected with the oil chamber of the piston of the other drive by means of a pipeline.
  • pistons which correspond by way of the connecting pipeline are associated in such a way that a piston which is carried along from the center of movement of the noncontrolled drive displaces a small amount of oil and pushes it through the connecting pipeline to the controlled drive; here the associated piston takes up, from the midposition onward, an amount of oil which is normally the same.
  • a special feature of this synchronization control is the fact that the communicating pipeline between two pistons in each case is the transmitting element for the movements of the noncontrolled drive, and also the measuring point of the synchronization error, and indicator of the adjustment value for the equalization of the running error.
  • the invention further comprises the cooperation of check valves and small pressure relief valves and the association of the replenishing and drainage processes for the connecting pipeline of the series-connected drives.
  • the uses of the invention include in particular the hydraulic adjusting gear of ships fin stabilizers, the steering gear of heavy land vehicles, large plate shears and folding presses with widely separated working cylinders.
  • FIG. 1 shows in diagrammatic form a circuit for synchronization control, in combination with a known seriesconnection of a hydraulic pump with an oil feed which can be controlled and reversed in direction, with two torsional drives in the form of vane-type motors, and
  • FIGS. 2 to 4 show details of the circuit.
  • the drives 2 and 3 in the form of torsional drives, shown as vane-type motors, are mechanically connected with control blocks 4 and 5. These contain controlled pistons 6 and 7', 8 and 9.
  • the pump 1 delivers pressure oil into a pipeline 10.
  • the drive 3 then rotates in the direction of the arrow and the drive 2, which is connected with the drive 3 by a pipeline l1, likewise in the direction indicated by the arrow. Displaced return oil flows back to the pump by way of a pipeline 12.
  • Each of the drives 3 and 2 operates by virtue of the pressure drop between the pipelines I and I2. If this is equal for both drives the pressure in the pipelines I0, 11 and 12 is in the ratio 2:1:0.
  • Levers 13 and 14 are driven respectively by the rotation of the drives 3 and 2 and push the pistons 7 and 8 outwardly from the middle.
  • the piston chambers 15 and 16 were placed under initial pressure by the working pressure in the pipeline by way of check valves 17 and 18.
  • a piston chamber 19 in which fluid pressure acts on a larger area of the piston 7 is subjected to the working pressure by way of a pipeline 20 from the pipeline 10.
  • An error of lead in drive 3 over drive 2 increases the pressure in a pipeline 25 with the result that a spring-loaded valve 26 is opened in proportion to the error and pressure oil passes from the higher level of pressure in the pipeline 10, by way of a check valve 17, the valve 26 and a pipeline 27, into the lower pressure level of the pipeline 11. This normalizes the insufficient volume in pipeline 11 again, i.e. the drives 3 and 2 move apart from one another.
  • valves 23 and 29 as well as of the valves 26 and 28 are chosen so that the vales 26 and 28 only react to a pressure slightly higher than the maximum working pressure, but the valves 23 and 29 have a response which is even higher than the maximum response pressure of the valves 26 and 28.
  • a lever 30 or 31 respectively is driven by the drive axle and with its adjusting pin 32 brushes past the stop 21 without making contact, whereby after every passage past the stop 21 a measuring piston remains stationary and the other is carried along.
  • the pistons of the noncontrolled drive are formed of solid cylinders with a circular end face, whereas those of the controlled drive are stepped the cross-sectional area of one annular surface being equal to the cross-sectional area ofone circular face (FIGS. 2 and 3).
  • the special advantages of this synchronization control are manifested in the possibility of very precise movement of the second reversible drive, which is not governed by the control system, even where the distances are fairly large and the space conditions difficult. Any substantial errors due to the compressibility of the oil in the measuring chambers and communication pipelines are avoided by the placing of the oil under an initial pressure. Inevitable errors due to small amounts of leakage oil from the measuring pistons cannot accumulate because as the pistons pass through the midpoint at any time the control process starts again with a fresh original position.
  • the synchronization control system operates with simple constructional elements of general oil-hydraulics and is supplied direct from the main hydraulic unit with pressure energy and new, filtered oil.
  • a method of synchronized control for two reversible hydraulic drives with a single hydraulic feed pump which is provided with a follower control which affects the movement of one of the two drives, the pump and the hydraulic drives being connected in series comprising providing a hydraulic control system for synchronization of the drive means in which this synchronization control means, in the event of lack of synchronism between the two drives, actuated by the motion of the drives generates pressure pulses which cause feeding in or draining off of an amount of fluid corresponding to the error in synchronism into the communication path between the two drives, and when passing through the midpositions of one drive these midpositions are utilized as the starting point for the generation of pressure pulses.
  • each of the drives can move a control piston in each direction of movement, whereby the drive which is not controlled displaces into a connecting pipeline a quantity of a hydraulic medium which is under initial pressure, while the control piston of the controlled drive takes up a quantity of hydraulic fluid from the pipeline.
  • Apparatus for synchronized control of two reversible hydraulic drives, both fed in series by a single pump, comprising a follower control which affects the movement of one of the drives said control having two groups of control pistons, each driven mechanically by one of the hydraulic drives, an actuating arm and associated adjusting pin driven by each drive, a stop, said arrangement being such that after each passage of an actuating arm one of the pistons of a group remains stationary and the other is moved.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
US859888A 1968-09-25 1969-09-22 Method and apparatus for the synchronized control of two hydraulic drives Expired - Lifetime US3595019A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681776120 DE1776120B2 (de) 1968-09-25 1968-09-25 Gleichlaufregeleinrichtung fuer zwei reversierbare hydraulische schwenkmotore

Publications (1)

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US3595019A true US3595019A (en) 1971-07-27

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US859888A Expired - Lifetime US3595019A (en) 1968-09-25 1969-09-22 Method and apparatus for the synchronized control of two hydraulic drives

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US (1) US3595019A (enrdf_load_stackoverflow)
JP (1) JPS5323471B1 (enrdf_load_stackoverflow)
DE (1) DE1776120B2 (enrdf_load_stackoverflow)
DK (1) DK139787C (enrdf_load_stackoverflow)
ES (1) ES371781A1 (enrdf_load_stackoverflow)
FR (1) FR2018830A1 (enrdf_load_stackoverflow)
GB (1) GB1271729A (enrdf_load_stackoverflow)
NL (1) NL148382B (enrdf_load_stackoverflow)
NO (1) NO129307B (enrdf_load_stackoverflow)
SE (1) SE356269B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110578727A (zh) * 2019-09-25 2019-12-17 张家口凯航液压科技有限公司 一种负载敏感多缸同步控制方法
CN113646545A (zh) * 2019-04-01 2021-11-12 穆格股份有限公司 用于减摇器驱动装置的液压系统
CN114439723A (zh) * 2022-02-18 2022-05-06 江苏理工学院 一种变量泵及其使用方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4431422A (en) * 1981-04-29 1984-02-14 Outboard Marine Corporation Marine hydraulic steering system control
US4578039A (en) * 1981-04-29 1986-03-25 Outboard Marine Corporation Marine hydraulic steering system control

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3070959A (en) * 1959-04-06 1963-01-01 Hydra Power Corp Fluid pressure operated mechanisms
US3359870A (en) * 1965-09-02 1967-12-26 Ashtabula Bow Socket Company Oscillating hydraulic actuator and circuit therefor
US3363418A (en) * 1965-10-01 1968-01-16 Carl G. Hebel Hydraulic remote control system
US3435616A (en) * 1966-03-01 1969-04-01 Danfoss As Equalizing system for hydraulic motors

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3070959A (en) * 1959-04-06 1963-01-01 Hydra Power Corp Fluid pressure operated mechanisms
US3359870A (en) * 1965-09-02 1967-12-26 Ashtabula Bow Socket Company Oscillating hydraulic actuator and circuit therefor
US3363418A (en) * 1965-10-01 1968-01-16 Carl G. Hebel Hydraulic remote control system
US3435616A (en) * 1966-03-01 1969-04-01 Danfoss As Equalizing system for hydraulic motors

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113646545A (zh) * 2019-04-01 2021-11-12 穆格股份有限公司 用于减摇器驱动装置的液压系统
CN113646545B (zh) * 2019-04-01 2024-09-06 穆格股份有限公司 用于减摇器驱动装置的液压系统
CN110578727A (zh) * 2019-09-25 2019-12-17 张家口凯航液压科技有限公司 一种负载敏感多缸同步控制方法
CN114439723A (zh) * 2022-02-18 2022-05-06 江苏理工学院 一种变量泵及其使用方法
CN114439723B (zh) * 2022-02-18 2023-07-07 江苏理工学院 一种变量泵及其使用方法

Also Published As

Publication number Publication date
ES371781A1 (es) 1972-03-16
JPS5323471B1 (enrdf_load_stackoverflow) 1978-07-14
NO129307B (enrdf_load_stackoverflow) 1974-03-25
SE356269B (enrdf_load_stackoverflow) 1973-05-21
DE1776120B2 (de) 1972-12-14
GB1271729A (en) 1972-04-26
NL148382B (nl) 1976-01-15
DK139787B (da) 1979-04-17
DE1776120A1 (de) 1971-04-01
NL6914337A (enrdf_load_stackoverflow) 1970-03-31
FR2018830A1 (enrdf_load_stackoverflow) 1970-06-26
DK139787C (da) 1979-10-01

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