US3620126A - Hydraulic reversing system for a reciprocating working member - Google Patents
Hydraulic reversing system for a reciprocating working member Download PDFInfo
- Publication number
- US3620126A US3620126A US3620126DA US3620126A US 3620126 A US3620126 A US 3620126A US 3620126D A US3620126D A US 3620126DA US 3620126 A US3620126 A US 3620126A
- Authority
- US
- United States
- Prior art keywords
- chambers
- main
- valve
- piston
- control
- 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
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L25/00—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means
- F01L25/02—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q5/00—Driving or feeding mechanisms; Control arrangements therefor
- B23Q5/02—Driving main working members
- B23Q5/027—Driving main working members reciprocating members
- B23Q5/033—Driving main working members reciprocating members driven essentially by fluid pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L25/00—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means
- F01L25/02—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means
- F01L25/04—Drive, or adjustment during the operation, or distribution or expansion valves by non-mechanical means by fluid means by working-fluid of machine or engine, e.g. free-piston machine
- F01L25/06—Arrangements with main and auxiliary valves, at least one of them being fluid-driven
- F01L25/063—Arrangements with main and auxiliary valves, at least one of them being fluid-driven the auxiliary valve being actuated by the working motor-piston or piston-rod
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T137/00—Fluid handling
- Y10T137/8593—Systems
- Y10T137/86493—Multi-way valve unit
- Y10T137/86574—Supply and exhaust
- Y10T137/8667—Reciprocating valve
- Y10T137/86694—Piston valve
- Y10T137/8671—With annular passage [e.g., spool]
Definitions
- a hydraulic reversing system for a reciprocating working member which is connected with a power cylinder receiving a main piston which subdivides the cylinder into displacement chambers.
- the main control valve comprises a piston with a central spool separating two working chambers from one another the Working chambers being connected to the displacement chambers of the main cylinder.
- a pair of control spools separate the main chambers of the valve from control chambers which are respectively connected to hydraulic impulse transmitters cooperating with the movable member for alternate operation on reciprocation thereof.
- an oil flow from the main valve inlet to the corresponding control compartment is terminated and the spool valve shifted in the opposite direction to reverse the ow of Huid to the displacement compartments of the main cylinder.
- the main hydraulic pressure serves to bias the control valve.
- This invention relates to a fully hydraulic device on a machine or apparatus having a part reciprocating in a straight line, for precision reversing of the movement of the part between two adjustable turnround (reversal) points in a manner substantially independent of load and velocity, the device including a pressurized-oil pump, land one or more impulse transmitter plungers actuated by the moving part.
- electromagnetically actuated hydraulic multi-way valves are used and are excited by electric impulse switches allocated to stops on the reciprocating part of the machine or apparatus.
- the contacts given in this way only trip the electric impulse and thus the braking phase, so that the effective braking paths after the reversing impulse are of varying length, according to the set velocity and the masses in motion.
- the device according to the invention is so designed that as soon as the impulse movement has been tripped the impulse transmitter plunger in question closes an overow pipe leading to the oil tanks (reservoir), whereupon the oil displaced Patented Nov.
- FIG. 1 shows a diagrammatic representation of a first fully hydraulic device such as can be used to advantage where small or insignificant load changes are to be expected, as for instance in the thread guides of winding mechanisms;
- FIG. 2 shows the device represented in FIG. l with individual parts in other positions
- FIG. 3 shows diagrammatically a second device which can be used to advantage where large load changes are to be expected, as for instance in a simple shaping machine with various cutting adjustments;
- FIG. 4 is a diagrammatic view of a third device for use in large metal-cutting machines, for instance parallel planing machines;
- FIG. 5 is an axial section through the main control valve
- FIG. 6 shows an impulse transmitter, also in axial section.
- numeral 1 denotes an oil tank from which a suction pipe 2 leads to a pressure pump 3. From this a pressurized-oil pipe 4, having a volumetric flow regulator S fitted therein, leads to the hydraulic control valve 6.
- This consists essentially of the body or housing 6a (FIGS. 1 and 5) and the piston (6k, 6I, 6m) which is axially movable therein.
- Numerals 6b to 6i designate various oil chambers of the valve body 6a.
- Two pipes 9a and 9b lead from chambers 6b and 6c to the displacement spaces 10a and 10b of the working cylinder 10 having therein an axially movable piston 10d mounted on a piston rod 10c.
- piston road 10c is connected (in a way not shown) with the part of the machine or apparatus which performs a reciprocating movement.
- piston rod 10c ⁇ carries two reversing elements 11 and 12, each of which is provided with a slanting contact surface 11a and 12a respectively.
- Two hydraulic impulse transmitters 13 and 14 are located at any desired position on the frame of the machine or apparatus. They each consist of a cylinder 13a or 14a and a plunger that can move inside it. The plungers are fitted with rods projecting from cylinders 13a or 14a, the ends 13e and 14C of which rods project into the path of the reversing elements 11 and 12 or more exactly of their contact surfaces 11a and 12a respectively.
- Overilows 13d and 14d are arranged in cylinders 13 and 14 and are open when plungers 13b and 14b are in the upper limiting position shown in FIG. 1, but are covered as the plungers move downwards. Pipes 15 and 16 lead from said overflows 13d and 14d back into the oil tank.
- Displacement spaces 13a and 14a of the impulse transmitters 13 and 14 are each connected through a pipe 17 or 18 to the oil chambers 6h and 6i respectively of the control valve. Said pipes have fitted therein a nonreturn valve 19 or 20 which can be bypassed by an adjustable throttle valve 21 or 22 respectively.
- Oil supplied by pump 3 flows through delivery pipe 4 and flow regulator 5 into chamber 6c of the control valve, whence through pipe 9b into space b of working cylinder 10, so that piston 10d, piston rod 10c and the part of the machine or apparatus connected to the latter are moved to the left in the direction of the arrow A in FIG. 1.
- the oil present in space 10a is thereby forced out and ows back through pipe 9a, the communicating chambers 6b and 6d of the control valve and pipe 7a and 7d into the oil tank 1.
- piston section 6l leaves a narrow annular clearance between chambers 6i and 6h.
- pressurized oil Hows from delivery pipe 4 through pipe 23 with a permanently adjusted throttle 22' into chamber 6h so as to cause piston of the control valve to move still further to the right.
- piston section 6m leaves a narrow annular clearance c free between chambers 6g and 61', so that oil from delivery pipe 4 also ows through pipe 24 with its built-in throttle 25 into chamber 6i.
- This oil does not have any effect on the piston, however, as it can escape through throttle valve 22, pipe 18, overow 14d and pipe 16 into the oil tank. This arrangement ensures constant venting and the supply of the necessary amount of oil to the impulse transmitter.
- piston section 6k frees the entry of delivery pipe 4 to chamber 6b so that pressurized oil flows through pipe 9a into space 10a of the working cylinder.
- Piston 10d, piston rod 10c and the part of the machine or apparatus connected thereto are thus moved to the right in the direction of the arrow B in FIG. 2, and the oil forced out of space 10b can flow back into oil tank 1 through pipe 9b, chambers 6c and 6e, pipes 7b and 7d and the nonreturn valve 8.
- the small plungers of the impulse transmitters are loaded by springs 13e and 14e, which tend to keep plungers 13b and 14b in their upper end position.
- numeral 1 again designates the oil tank, 2 the suction pipe, 3 the oil pump, 4 at the delivery pipe, 6 the control valve, 9a and 9b the pipes leading from the latter to the displacement spaces 10a and 10b of the working cylinder, 11 and 12 the reversing elements mounted on piston rod 10c with its piston 4 10d, 13 and 14 the impulse transmitters, l5 and 16 the overflow pipes, 17 and 18 the pipes connecting the impulse transmitters to the control valve with their non-return valves 19 and 20 and the throttle valves 21 and 22 respectively fitted in parallel therewith.
- numeral 1 again designates the oil tank, 2 the suction pipe, 3 the pressure pump, 4 the delivery pipe leading to the control valve 6; 9a and 9b the pipes leading from the latter to the working cylinder 10; 10d the working piston with piston road 10c and reversing elements 11 and l2 attached thereto, 13 and 14 the impulse transmitters with overow pipes 1S and 16; 17 and 18 the pipes leading from the impulse transmitters to the control valve 6 with their non-return valves 19 and 20 and the throttle valves 21 and 22 respectively fitted in parallel therewith.
- FIG. 4 differs from the two forms described hereinbefore in that pump 3 is arranged for electric adjustment of delivery, being in addition equipped with slip compensation to counterbalance its internal leakage losses, according to load and pressure.
- the device is also provided with an auxiliary pump 29 for constant delivery.
- a pipe 30 leads from this auxiliary pump 29 to an auxiliary control valve 31 fitted in advance of the working cylinder 10 and designed as a four-way slide valve. From this four-way valve two pipes 32 and 33 branch off to pipes 9a and 9b respectively, while a further pipe 34 leads to the oil tank.
- 'Iiwo further pipes 37 and 38 lead from auxiliary pump 29 by way of ow regulators 3S and 36 to chambers 6f and 6g of the main control valve 6 respectively.
- the pump 29 serves also to determine the displacement rate of the control piston since this pump alone constitutes its source of control uid.
- Auxiliary pump 29, in conjunction with the four-way valve 31, permits working cylinder 1I] to be operated at low speed without the main operating pump 3, which is adjusted to the working speed.
- FIG. 4 represents a system in which the auxiliary pump 29 is connected via the line 30 and a further control valve 31 to the lines 32, 33 supplying the main working chambers of the power cylinder means 10.
- the valve 31 When the valve 31 is switched into its craw position in either direction, the tluid from the auxiliary pump is delivered to one of the chambers of the power cylinder and returned to the reservoir from the other chamber.
- the valve 31 thus allows the power cylinder to be controlled solely by the supply rate of the auxiliary pump 29 when slow displacement of the hydraulic member is desired.
- the impulse transmitter plungers can be actuated directly by piston rod 10c or the part of the machine or apparatus connected thereto, i.e. without the use of the slanting contact surfaces 11a and 12a., in which case the impulse transmitter plunger rods face each other in the direction of motion.
- machine tables have to be reversed, as for instance in small or heavy machine-tools, such as parallel planing machines, reversing cams or contact surfaces are to be recommended adapted to translate the stroke of the impulse transmitter plungers arranged at right angles to the stroke of the working piston in accordance with the braking distance and which can also run over at crawling speed with the oil from auxiliary pump 29 when the main pump is switched olf.
- control valve 6 it is preferable for control valve 6 to be so designed that in the middle position of the piston (FIG. the two sealing edges 6k' and 6k", as well as the inner sealing edges 6l” and 6m" of the two outer piston collars 6l and 6m, are ilush with or lie in the same plane as the sealing edges 4', 4", 6d and 6e' of the outlet of delivery pipe 4 and oil chambers 6d and 6e, so that they result in linear sealing as opposed to surface sealing, while the outer edges 6l and 6m of piston collars 6l and 6m are set back in relation to the edges 6;" and 6g of the ol chambers f and 6g respectively and thus form an annular clearance C'.
- ⁇ It is also possible to have the adjustable throttling and nonreturn valves 19, 21 and 20, 22 incorporated in the body 6a of control valve, as diagrammatically shown in FIG. 5.
- a hydraulic reversing system for a reciprocating working member comprising:
- power-cylinder means including at least one power piston connected with said member for displacing same and a pair of main chambers for pressurization of the piston to urge said member in opposite direction;
- control valve including a housing and a valve piston shiftable in said housing and subdividing same into a pair of main compartments respectively connected with said chambers and alternately connectable with said pump upon reciprocation of said valve piston in opposite directions, said valve piston further defining in said housing a pair of oppositely elfective control compartments respectively connected with said source;
- a pair of hydraulic impulse transmitters each connected with a respective one of said control chambers and provided with an overow permitting the outliow of iluid from the respective control chamber, and with a plunger actuatable by said member upon movement thereof in a respective direction to block said overl tliow and thereby pressurize the respective control chamber to bias said valve piston in an opposite direction and consequent pressurization of said power-cylinder means to displace said member in the opposite direction, said valve being so constructed and arranged that the uid in said control compartments biases a displaced one of said plungers into an initial position to reopen the respective overflow.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Fluid-Pressure Circuits (AREA)
- Reciprocating Pumps (AREA)
- Hydraulic Motors (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH946268A CH473319A (de) | 1968-06-19 | 1968-06-19 | Vollhydraulische Vorrichtung an Maschine oder Apparat mit geradlinig hin- und hergehendem Teil, für weitgehend last- und geschwindigkeitsunabhängige Genauigkeitsumsteuerung der Bewegung des Teils zwischen zwei einstellbaren Umsteuerpunkten |
Publications (1)
Publication Number | Publication Date |
---|---|
US3620126A true US3620126A (en) | 1971-11-16 |
Family
ID=4352230
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US3620126D Expired - Lifetime US3620126A (en) | 1968-06-19 | 1969-06-04 | Hydraulic reversing system for a reciprocating working member |
Country Status (7)
Country | Link |
---|---|
US (1) | US3620126A (de) |
AT (1) | AT290237B (de) |
CH (1) | CH473319A (de) |
DE (2) | DE1923741A1 (de) |
FR (1) | FR2011180A1 (de) |
GB (1) | GB1245703A (de) |
SE (1) | SE342569B (de) |
Cited By (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3800664A (en) * | 1971-02-10 | 1974-04-02 | Dobson Park Ind | Impact tools or apparatus |
US3865420A (en) * | 1973-04-12 | 1975-02-11 | William H Warren | Vacuum control system |
US4037520A (en) * | 1975-08-29 | 1977-07-26 | Herbert Edward Jakob | Fluid motor apparatus |
US4398463A (en) * | 1981-08-19 | 1983-08-16 | Motter Printing Press Co. | Non-repeat doctor blade drive |
US4438628A (en) * | 1980-12-19 | 1984-03-27 | Creamer Reginald D | Pump jack drive apparatus |
US4491055A (en) * | 1981-11-02 | 1985-01-01 | Otis Engineering Corporation | Control of continuous reciprocation of a fluid power cylinder |
US4505109A (en) * | 1979-11-16 | 1985-03-19 | Danfoss A/S | Hydraulic control apparatus particularly steering apparatus |
US4691511A (en) * | 1982-12-14 | 1987-09-08 | Otis Engineering Corporation | Hydraulic well pump |
US4693171A (en) * | 1982-12-14 | 1987-09-15 | Otis Engineering Corporation | Position responsive valve control for hydraulic cylinder |
US5193661A (en) * | 1992-02-05 | 1993-03-16 | Foster Raymond K | System of linear hydraulic motors |
US20030173210A1 (en) * | 2000-08-15 | 2003-09-18 | Parker Hannifin Ab | Pneumatic actuator system |
WO2009033193A1 (en) * | 2007-09-05 | 2009-03-12 | African Explosive Limited | Controlvalve |
US7513920B2 (en) | 2002-02-11 | 2009-04-07 | Dupont Air Products Nanomaterials Llc | Free radical-forming activator attached to solid and used to enhance CMP formulations |
US20100107863A1 (en) * | 2006-11-13 | 2010-05-06 | Vesa Ropponen | Device meant for controlling of an oscillating cylinder |
US8474363B2 (en) | 2011-07-03 | 2013-07-02 | Vincent M. Kelly | Axial piston and valve shaft fluid engine |
US8753564B2 (en) | 2011-06-13 | 2014-06-17 | Mac Valves, Inc. | Piston rod and cylinder seal device for aluminum bath crust breaker |
US8906291B2 (en) | 2011-06-13 | 2014-12-09 | Mac Valves, Inc. | Piston rod and cylinder seal device for aluminum bath crust breaker |
US8910562B2 (en) | 2011-06-13 | 2014-12-16 | Mac Valves, Inc. | Pneumatic system for controlling aluminum bath crust breaker |
US8932515B2 (en) | 2011-06-13 | 2015-01-13 | La-Z-Boy Incorporated | Crust breaker aluminum bath detection system |
CN110425264A (zh) * | 2019-09-04 | 2019-11-08 | 山东雷沃传动有限公司 | 一种电液控制变速箱的控制系统及控制方法 |
EP3698053A4 (de) * | 2017-10-20 | 2021-07-14 | Pimatic Oy | Oszillationszylinderanordnung |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL168589C (nl) * | 1970-03-12 | 1982-04-16 | Uhde Gmbh Friedrich | Besturingssysteem voor een door middel van een drukmedium werkzame aandrijving van een aggregaat. |
US3643548A (en) * | 1970-04-20 | 1972-02-22 | Butterworth Hydraulic Dev Ltd | Fluid-pressure-operated motors |
DE3044675A1 (de) * | 1980-11-27 | 1982-07-08 | Leybold-Heraeus GmbH, 5000 Köln | Verfahren zur steuerung eines hydraulischen antriebs und fuer die durchfuehrung dieses steuerungsverfahrens geeigneter hydraulischer antrieb |
DE3117027A1 (de) * | 1981-04-29 | 1982-11-25 | Manfred Ing.(grad.) 4320 Hattingen Fischbach | "verpresseinrichtung zum traenken des gebirges, vorzugsweise fuer das verkleben mit fluessigem kunststoff" |
FR2642796B1 (fr) * | 1989-02-06 | 1994-05-06 | Lavoisiere Andre | Pompe a piston alternatif autoreversible a transmission hydraulique du signal d'inversion |
DE4031649C2 (de) * | 1990-10-05 | 1994-03-31 | Mgv Moest Spritzgeraete Prod | Dosier- und Mischanlage |
CN106979373A (zh) * | 2017-05-15 | 2017-07-25 | 中治赛迪装备有限公司 | 一种大通径液动闸板阀的低冲击液压控制系统及其控制方法 |
CN115306667B (zh) * | 2022-08-19 | 2023-10-27 | 锐捷智创(浙江)机械科技有限公司 | 一种平稳输出液压油的油压气动泵 |
-
1968
- 1968-06-19 CH CH946268A patent/CH473319A/de not_active IP Right Cessation
- 1968-07-25 AT AT721368A patent/AT290237B/de not_active IP Right Cessation
-
1969
- 1969-05-09 DE DE19691923741 patent/DE1923741A1/de not_active Withdrawn
- 1969-05-09 DE DE6918886U patent/DE6918886U/de not_active Expired
- 1969-05-21 SE SE717069A patent/SE342569B/xx unknown
- 1969-05-29 FR FR6917618A patent/FR2011180A1/fr not_active Withdrawn
- 1969-06-04 US US3620126D patent/US3620126A/en not_active Expired - Lifetime
- 1969-06-06 GB GB2878669A patent/GB1245703A/en not_active Expired
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3800664A (en) * | 1971-02-10 | 1974-04-02 | Dobson Park Ind | Impact tools or apparatus |
US3865420A (en) * | 1973-04-12 | 1975-02-11 | William H Warren | Vacuum control system |
US4037520A (en) * | 1975-08-29 | 1977-07-26 | Herbert Edward Jakob | Fluid motor apparatus |
US4505109A (en) * | 1979-11-16 | 1985-03-19 | Danfoss A/S | Hydraulic control apparatus particularly steering apparatus |
US4438628A (en) * | 1980-12-19 | 1984-03-27 | Creamer Reginald D | Pump jack drive apparatus |
US4398463A (en) * | 1981-08-19 | 1983-08-16 | Motter Printing Press Co. | Non-repeat doctor blade drive |
US4491055A (en) * | 1981-11-02 | 1985-01-01 | Otis Engineering Corporation | Control of continuous reciprocation of a fluid power cylinder |
US4691511A (en) * | 1982-12-14 | 1987-09-08 | Otis Engineering Corporation | Hydraulic well pump |
US4693171A (en) * | 1982-12-14 | 1987-09-15 | Otis Engineering Corporation | Position responsive valve control for hydraulic cylinder |
US5193661A (en) * | 1992-02-05 | 1993-03-16 | Foster Raymond K | System of linear hydraulic motors |
US20030173210A1 (en) * | 2000-08-15 | 2003-09-18 | Parker Hannifin Ab | Pneumatic actuator system |
US6776081B2 (en) * | 2000-08-15 | 2004-08-17 | Parker Hannifin Ab | Pneumatic actuator system |
US7513920B2 (en) | 2002-02-11 | 2009-04-07 | Dupont Air Products Nanomaterials Llc | Free radical-forming activator attached to solid and used to enhance CMP formulations |
US20100107863A1 (en) * | 2006-11-13 | 2010-05-06 | Vesa Ropponen | Device meant for controlling of an oscillating cylinder |
WO2009033193A1 (en) * | 2007-09-05 | 2009-03-12 | African Explosive Limited | Controlvalve |
US8753564B2 (en) | 2011-06-13 | 2014-06-17 | Mac Valves, Inc. | Piston rod and cylinder seal device for aluminum bath crust breaker |
US8906291B2 (en) | 2011-06-13 | 2014-12-09 | Mac Valves, Inc. | Piston rod and cylinder seal device for aluminum bath crust breaker |
US8910562B2 (en) | 2011-06-13 | 2014-12-16 | Mac Valves, Inc. | Pneumatic system for controlling aluminum bath crust breaker |
US8932515B2 (en) | 2011-06-13 | 2015-01-13 | La-Z-Boy Incorporated | Crust breaker aluminum bath detection system |
US8474363B2 (en) | 2011-07-03 | 2013-07-02 | Vincent M. Kelly | Axial piston and valve shaft fluid engine |
EP3698053A4 (de) * | 2017-10-20 | 2021-07-14 | Pimatic Oy | Oszillationszylinderanordnung |
CN110425264A (zh) * | 2019-09-04 | 2019-11-08 | 山东雷沃传动有限公司 | 一种电液控制变速箱的控制系统及控制方法 |
CN110425264B (zh) * | 2019-09-04 | 2024-02-06 | 山东雷沃传动有限公司 | 一种电液控制变速箱的控制系统及控制方法 |
Also Published As
Publication number | Publication date |
---|---|
CH473319A (de) | 1969-05-31 |
AT290237B (de) | 1971-05-25 |
DE1923741A1 (de) | 1970-01-02 |
GB1245703A (en) | 1971-09-08 |
SE342569B (de) | 1972-02-14 |
FR2011180A1 (de) | 1970-02-27 |
DE6918886U (de) | 1973-09-13 |
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