EP1387090A2 - Hydraulic drive - Google Patents

Hydraulic drive Download PDF

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Publication number
EP1387090A2
EP1387090A2 EP03015768A EP03015768A EP1387090A2 EP 1387090 A2 EP1387090 A2 EP 1387090A2 EP 03015768 A EP03015768 A EP 03015768A EP 03015768 A EP03015768 A EP 03015768A EP 1387090 A2 EP1387090 A2 EP 1387090A2
Authority
EP
European Patent Office
Prior art keywords
pressure
hydraulic drive
line
pump
drive according
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.)
Granted
Application number
EP03015768A
Other languages
German (de)
French (fr)
Other versions
EP1387090B1 (en
EP1387090A3 (en
Inventor
Michael Bökmann
Norbert Gwozdz
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.)
Bosch Rexroth AG
Original Assignee
Bosch Rexroth 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 DE10329067A external-priority patent/DE10329067A1/en
Application filed by Bosch Rexroth AG filed Critical Bosch Rexroth AG
Priority to EP04029899.4A priority Critical patent/EP1564414B1/en
Publication of EP1387090A2 publication Critical patent/EP1387090A2/en
Publication of EP1387090A3 publication Critical patent/EP1387090A3/en
Application granted granted Critical
Publication of EP1387090B1 publication Critical patent/EP1387090B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0423—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling pump output or bypass, other than to maintain constant speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • F15B11/0426—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in" by controlling the number of pumps or parallel valves switched on
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1476—Special return means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F15B2211/20584—Combinations of pumps with high and low capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41527—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a directional control valve
    • F15B2211/41536—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a directional control valve being connected to multiple ports of an output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/47—Flow control in one direction only
    • F15B2211/473—Flow control in one direction only without restriction in the reverse direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6651—Control of the prime mover, e.g. control of the output torque or rotational speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/75—Control of speed of the output member

Definitions

  • the invention relates to a hydraulic drive for a consumer, especially for a Hydraulic cylinder according to the preamble of the claim 1.
  • a hydraulic drive is known from US Pat. No. 6,379,119 known for a lifting cylinder.
  • a bottom one Cylinder space of the lifting cylinder is constant Pump with variable-speed electric motor with pressure medium supplied from a tank.
  • a piston rod side Annulus of the lifting cylinder is with a hydraulic accumulator connected.
  • the in the stroke direction (extension of the cylinder) effective pressure is thus through the constant pump and in the opposite direction effective pressure by the pressure in Hydraulic accumulator determined.
  • To retract the hydraulic cylinder is the control of the constant pump Reverse direction of rotation, so that pressure medium from the Cylinder space is flowing into the tank and the cylinder by the pressure in the hydraulic accumulator or annulus and the The weight of the load retracts.
  • the constant pump works as a motor and the electric motor as a generator, see above that the power gained is fed back into the network can be.
  • the hydraulic accumulator is filled via a Switching valve, which in normal operation of the lifting cylinder is in a locked position and in a resting phase of the or of the consumers connected to the constant pump in a through position is brought so that the Hydraulic accumulator can be charged via the constant pump can.
  • a hydraulic drive is in DE 196 31 804 A1 for a lifting cylinder of an elevator, which is disclosed as this is designed as a plunger cylinder.
  • the cylinder space becomes a load via a constant pump pressurized by a variable-speed drive is driven.
  • a variable-speed drive is driven.
  • the throttle becomes a pressure medium flow branched off to the tank so that the pump with higher Speed must run than this without the throttle open would be the case.
  • This increase in speed is a even supply of pressure medium to the consumer and Lubrication of the constant pump guaranteed.
  • To lower the load becomes the direction of rotation of the constant pump vice versa, so this as the motor and the connected Electric motor works as a generator.
  • the invention has for its object a hydraulic Drive for one of a pump arrangement and a hydraulic accumulator pressurized consumer to develop such that the pressure in the hydraulic accumulator constant with little expenditure on device technology can be held.
  • the hydraulic drive has a Bypass line, via which one from the pump arrangement to Consumer leading pressure line and one from the hydraulic accumulator storage line leading to the consumer with each other are connected.
  • a bypass line Current valve or a pressure reducing valve provided over that for filling the hydraulic accumulator pressure medium from the Pressure line can flow into the storage line, so that it is guaranteed that the hydraulic accumulator also during of the operation of the consumer can be charged.
  • the flow control valve can - preferably adjustable - choke or a flow control valve.
  • the consumer is preferably a hydraulic cylinder executed.
  • the pump arrangement is via a pressure line to a cylinder chamber on the bottom and the hydraulic accumulator via the storage line to a piston rod side Annulus is connected.
  • the Bypass line via a pressure relief valve with a Tank connected so that the maximum storage pressure through limits the value set on the pressure relief valve is.
  • the hydraulic accumulator via the bypass line can prevent in this one towards the storage line opening check valve are provided.
  • this bypass line can also be in the piston of the cylinder can be integrated.
  • the consumer preferably the cylinder, is at an advantageous embodiment, a displacement sensor assigned via which the stroke position of the piston is detected and a corresponding control of the pump arrangement and possibly the throttle device.
  • this can be a Safety valve upstream.
  • this is achieved by a Valve arrangement achieved via the at low consumer pressure both pumps are connected to the consumer and when a threshold pressure is reached, the pump with the larger stroke volume on pressureless circulation or the same is switched so that only the smaller pump is effective.
  • the hydraulic drive according to the invention can be particularly advantageous for a bending cylinder Insert bending press.
  • the single figure shows a circuit diagram of an inventive hydraulic drive for a bending press.
  • a bending press 1 has a double-acting design Bending cylinder 2, one over a machine bed clamped workpiece 4 with the one for bending required force can be applied.
  • the bending cylinder 2 is an open circuit hydraulic drive with a pump arrangement 6 and a Hydraulic accumulator 8 assigned.
  • the pump arrangement 6 can be drawn from a tank T and via a pressure medium Pressure line 10 in a bottom-side cylinder space 12 of the bending cylinder 2 are promoted.
  • the hydraulic accumulator 8 is via a storage line 14 with a piston rod side Annulus 16 of the bending cylinder 2 connected.
  • the pump arrangement 6 has a variable-speed drive 18, so that to extend the bending cylinder 2 to the workpiece 4 out pressure medium from the tank T via the pump arrangement 6, the pressure line 10 into the cylinder space 12 is promoted. This effective pressure in the direction of extension acts the pressure in the hydraulic accumulator 8 corresponding Pressure in the annular space 16 counter. To retract the bending cylinder 2, the direction of rotation of the pump assembly 6 over the variable-speed drive 18 reversed, so that Pressure medium from the cylinder chamber 12 via the pump arrangement 6 flows out to the tank. The pressure in the hydraulic accumulator 8 then acts in the retracting direction so that the piston of the Bending cylinder 2 is retracted. At this run-in the pump arrangement 6 acts as a motor, so that accordingly the drive 18, for example an asynchronous motor, as Generator works.
  • the stroke position of the bending cylinder 2 is via a Displacement sensor 20 detects, so that depending on whose signal the control of the drive 18 take place can.
  • bypass line 22 There is a special feature of the solution according to the invention in that the one shown in the figure Embodiment of the memory line 14 and the pressure line 10 connected to one another via a bypass line 22 are. There is an adjustable one in this bypass line Throttle device 24 arranged.
  • the bypass line 22 is also with a pressure relief valve 26 connected to the tank T. Via the pressure relief valve 26 the pressure in the hydraulic accumulator 8 to one predetermined, comparatively low limit set.
  • a check valve 28 is provided which in the direction of Storage line 14 opens.
  • This check valve 28 prevents that when the bending cylinder is retracted 2 Pressure medium from the annular space 16 or from the hydraulic accumulator 8 in the pressure line 10 flows in and thus the hydraulic accumulator 8 is discharged - in this case, the bending cylinder 2 stop or its return movement slowed down.
  • throttle device 24 can in the Bypass line 22 also a flow control valve (not shown) are provided, via which the Storage line 14 inflowing pressure medium volume flow regardless of the pressure difference in the pressure line 10 and is in memory line 14.
  • Another alternative solution may be for certain Applications include throttle 24 and if necessary, the pressure relief valve 26 by a Replace pressure reducing valve. Through this valve the pressure in the storage line 14 (secondary pressure) kept constant, with the valve increasing pressure in the storage line increasingly closes and eventually only leakage losses in the storage line balances.
  • the hydraulic accumulator 8 preceded a safety valve 30.
  • a flow of pressure medium for charging the Hydraulic accumulator 8 branched off from the pressure line 10 so that it is ensured that this is always on the predetermined limit is charged. Since that Pressure relief valve 26 when this limit is reached opens and thus a low pressure medium flow over the Bypass line 22 to tank T arises, the Pump arrangement 6 operated at a slightly higher speed be than this in the solutions according to the invention without Bypass line is the case. Through this speed increase pressure pulsation of the pump is reduced so that a smooth extension movement of the bending cylinder 2 is guaranteed.
  • the large pump 32 is via a low pressure pump line 42 and a switching valve 44 with the pressure line 10 connected.
  • This switching valve 44 opens in its spring-loaded basic position the connection between the low pressure pump line 42 and the pressure line 10.
  • a control surface acting against the force of a spring 46 of the switching valve 44 is via a control line 48 pressurized in the pressure line 10.
  • the switching valve 44 in switched a switching position in which the low pressure pump line 42 is connected to the tank T - the big one Pump 32 is then also switched to pressureless circulation. Similar to the small pump 30, the pressure of the large pump 32 via another pump pressure relief valve 50 limited to a maximum value.
  • the Low-pressure pump line 42 branches another suction line 52 with check valve 54.
  • both pumps 30, 32 from the variable-speed drive 18 driven.
  • the switching valve 44 is in its basic position so that the pressure medium flows both pumps 30, 32 added and via the pressure line 10 are conveyed into the cylinder chamber 12.
  • the Bending cylinder 2 runs with a comparatively high Speed off and builds up in the cylinder chamber 12 appropriate pressure on.
  • the switching valve 44 is in its second switching position switched so that the Low pressure pump line 42 is connected to the tank T. From this threshold pressure, only the small pump delivers 30 pressure medium to the bending cylinder 2nd i.e. to hold the Stroke position of the bending cylinder 2 and to build the Only the smaller pump 30 becomes the maximum pressure used so that at such high pressures on the Pump acting restoring torque is comparatively low and correspondingly the drive 18 with a lower torque can be interpreted.
  • the applicant reserves the right to do the two of one variable speed drive with driven pumps different stroke volumes to the subject of a Make divisional registration.
  • the Bypass line 22 with the associated valve arrangement executed as an independent component. In principle is it is also possible to bypass this 22 in the Integrate hydraulic cylinder 2.
  • a hydraulic drive for one is disclosed Consumer, preferably for a double-acting Cylinder, one of which is a pressure chamber via a pump arrangement can be supplied with pressure medium with variable-speed drive is, while a pressure chamber effective in the opposite direction with the pressure of a hydraulic accumulator is applied.
  • the hydraulic accumulator can be charged via a pressure medium Bypass line and a flow valve or a Pressure reducing valve from that of the pump assembly conveyed pressure medium flow are branched off, so that charging even while the or Consumer is possible.
  • the application discloses furthermore a pump arrangement in which two pumps with different stroke volumes from a common one variable-speed drive are driven, with high pressures on the consumer only with the pump lower displacement is effective, so the drive can be designed with comparatively small torque can.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The hydraulic drive is for a double-action cylinder (2) with two cavities (12, 16), one of which is supplied from a store (8). To charge the store, fluid can be passed through a bypass line (22) and a flow valve or a pressure reduction valve, to facilitate charging while the system is in use. The system includes two pumps (30, 32) of different swept volumes.

Description

Die Erfindung betrifft einen hydraulischen Antrieb für einen Verbraucher, insbesondere für einen Hydrozylinder gemäß dem Oberbegriff des Patentanspruchs 1.The invention relates to a hydraulic drive for a consumer, especially for a Hydraulic cylinder according to the preamble of the claim 1.

Aus der US 6,379,119 ist ein hydraulischer Antrieb für einen Hubzylinder bekannt. Ein bodenseitiger Zylinderraum des Hubzylinders wird über eine konstante Pumpe mit drehzahlvariablem Elektromotor mit Druckmittel aus einem Tank versorgt. Ein kolbenstangenseitiger Ringraum der Hubzylinders ist mit einem Hydrospeicher verbunden. Der in Hubrichtung (Ausfahren des Zylinders) wirksame Druck wird somit durch die Konstantpumpe und der in Gegenrichtung wirksame Druck durch den Druck im Hydrospeicher bestimmt. Zum Einfahren des Hydrozylinders wird über die Steuerung der Konstantpumpe die Drehrichtung umgekehrt, so dass Druckmittel aus dem Zylinderraum in den Tank strömt wird und der Zylinder durch den Druck im Hydrospeicher bzw. Ringraum und die Gewichtskraft der Last einfährt.A hydraulic drive is known from US Pat. No. 6,379,119 known for a lifting cylinder. A bottom one Cylinder space of the lifting cylinder is constant Pump with variable-speed electric motor with pressure medium supplied from a tank. A piston rod side Annulus of the lifting cylinder is with a hydraulic accumulator connected. The in the stroke direction (extension of the cylinder) effective pressure is thus through the constant pump and in the opposite direction effective pressure by the pressure in Hydraulic accumulator determined. To retract the hydraulic cylinder is the control of the constant pump Reverse direction of rotation, so that pressure medium from the Cylinder space is flowing into the tank and the cylinder by the pressure in the hydraulic accumulator or annulus and the The weight of the load retracts.

Bei Umkehr der Drehzahl arbeitet somit die Konstantpumpe als Motor und der Elektromotor als Generator, so dass die gewonnene Leistung ins Netz zurückgespeist werden kann.When the speed is reversed, the constant pump works as a motor and the electric motor as a generator, see above that the power gained is fed back into the network can be.

Das Befüllen des Hydrospeichers erfolgt über ein Schaltventil, das im normalen Betrieb des Hubzylinders in einer Sperrstellung ist und in einer Ruhephase des oder der an die Konstantpumpe angeschlossenen Verbraucher in eine Durchgangsstellung gebracht wird, so dass der Hydrospeicher über die Konstantpumpe aufgeladen werden kann.The hydraulic accumulator is filled via a Switching valve, which in normal operation of the lifting cylinder is in a locked position and in a resting phase of the or of the consumers connected to the constant pump in a through position is brought so that the Hydraulic accumulator can be charged via the constant pump can.

Nachteilig bei dieser Lösung ist, dass zum einen der vorrichtungstechnische Aufwand zum Befüllen des Hydrospeichers relativ hoch ist und dass zum anderen der Hydrospeicher nur in den Ruhephasen aufgeladen werden kann, so dass der Druck im Hydrospeicher während des Betriebs der Anlage unter einem vorbestimmten Grenzwert absinken und somit die Funktion des Hubzylinders nicht mehr in der vorbestimmten Weise gewährleistet ist.The disadvantage of this solution is that, on the one hand, the device-related effort for filling the hydraulic accumulator is relatively high and that on the other hand the Hydraulic accumulators can only be charged in the resting phases can, so that the pressure in the hydraulic accumulator during the Operation of the plant below a predetermined limit sink and therefore the function of the lifting cylinder does not more is guaranteed in the predetermined manner.

In der DE 196 31 804 A1 ist ein hydraulischer Antrieb für einen Hubzylinder eines Aufzugs offenbart, der als dieser als Plungerzylinder ausgeführt ist. Zum Anheben einer Last wird der Zylinderraum über eine Konstantpumpe mit Druckmittel beaufschlagt, die von einem drehzahlvariablen Antrieb angetrieben ist. Um eine Druckpulsation bei niedriger Drehzahl der Pumpe und eine Verbesserung der Pumpenschmierung zu ermöglichen, ist eine sich zwischen dem Druckanschluß der Pumpe und dem Hydrozylinder erstreckende Druckleitung über eine verstellbare Drossel mit dem Tank verbunden. Über diese Drossel wird bei geringen Drehzahlen ein Druckmittelstrom zum Tank abgezweigt, so dass die Pumpe mit höherer Drehzahl laufen muß, als dies ohne geöffnete Drossel der Fall wäre. Durch diese Erhöhung der Drehzahl ist eine gleichmäßig Druckmittelversorgung des Verbrauchers und Schmierung der Konstantpumpe gewährleistet. Zum Absenken der Last wird die Drehrichtung der Konstantpumpe umgekehrt, so dass diese als Motor und der angeschlossene Elektromotor als Generator arbeitet.A hydraulic drive is in DE 196 31 804 A1 for a lifting cylinder of an elevator, which is disclosed as this is designed as a plunger cylinder. For lifting The cylinder space becomes a load via a constant pump pressurized by a variable-speed drive is driven. To one Pressure pulsation at low pump speed and one Enabling pump lubrication is possible one between the pressure connection of the pump and the Hydraulic cylinder extending pressure line via a adjustable throttle connected to the tank. About these At low speeds, the throttle becomes a pressure medium flow branched off to the tank so that the pump with higher Speed must run than this without the throttle open Would be the case. This increase in speed is a even supply of pressure medium to the consumer and Lubrication of the constant pump guaranteed. To lower the load becomes the direction of rotation of the constant pump vice versa, so this as the motor and the connected Electric motor works as a generator.

Nachteilig bei dieser Lösung ist, dass aufgrund der Verwendung eines einfach wirkenden Zylinders die Einfahrbewegung des Zylinders im wesentlichen durch die wirksame Last und Drehzahl der als Motor wirkenden Konstantpumpe bestimmt ist, da in Absenkrichtung - nicht wie beim vorbeschriebenen Ausführungsbeispiel - kein Druck wirkt.The disadvantage of this solution is that due to the Use a single acting cylinder to retract of the cylinder essentially through the effective Load and speed of the constant pump acting as a motor is determined because in the lowering direction - not as with The embodiment described above - no pressure acts.

Der Erfindung liegt die Aufgabe zugrunde, einen hydraulischen Antrieb für einen von einer Pumpanordnung und einem Hydrospeicher mit Druck beaufschlagten Verbraucher derart weiterzubilden, dass der Druck im Hydrospeicher mit geringem vorrichtungstechnischem Aufwand konstant gehalten werden kann.The invention has for its object a hydraulic Drive for one of a pump arrangement and a hydraulic accumulator pressurized consumer to develop such that the pressure in the hydraulic accumulator constant with little expenditure on device technology can be held.

Diese Aufgabe wird durch einen hydraulischen Antrieb mit den Merkmalen des Patentanspruchs 1 gelöst.This task is done by a hydraulic drive solved with the features of claim 1.

Erfindungsgemäß hat der hydraulische Antrieb eine Bypassleitung, über die eine von der Pumpanordnung zum Verbraucher führende Druckleitung und eine vom Hydrospeicher zum Verbraucher führende Speicherleitung miteinander verbunden sind. In dieser Bypassleitung ist ein Stromventil oder ein Druckminderventil vorgesehen, über das zum Befüllen des Hydrospeichers Druckmittel von der Druckleitung in die Speicherleitung strömen kann, so dass gewährleistet ist, dass der Hydrospeicher auch während des Betriebes der Verbraucher aufgeladen werden kann.According to the hydraulic drive has a Bypass line, via which one from the pump arrangement to Consumer leading pressure line and one from the hydraulic accumulator storage line leading to the consumer with each other are connected. There is a in this bypass line Current valve or a pressure reducing valve provided over that for filling the hydraulic accumulator pressure medium from the Pressure line can flow into the storage line, so that it is guaranteed that the hydraulic accumulator also during of the operation of the consumer can be charged.

Das Stromregelventil kann eine - vorzugsweise einstellbare - Drossel oder ein Stromregelventil sein.The flow control valve can - preferably adjustable - choke or a flow control valve.

Der Verbraucher ist vorzugsweise als Hydrozylinder ausgeführt. Die Pumpanordnung ist über eine Druckleitung an einen bodenseitigen Zylinderraum und der Hydrospeicher über die Speicherleitung an einen kolbenstangenseitigen Ringraum angeschlossen ist.The consumer is preferably a hydraulic cylinder executed. The pump arrangement is via a pressure line to a cylinder chamber on the bottom and the hydraulic accumulator via the storage line to a piston rod side Annulus is connected.

Bei einem bevorzugten Ausführungsbeispiel ist die Bypassleitung über ein Druckbegrenzungsventil mit einem Tank verbunden, so dass der maximale Speicherdruck durch den am Druckbegrenzungsventil eingestellten Wert begrenzt ist. Ein weiterer Vorteil dieser erfindungsgemäßen Variante besteht darin, dass durch das über das Stromregelventil und das auf einen niedrigen Wert eingestellte Druckbegrenzungsventil oder über das Druckminderventil abströmende Druckmittel die Pumpendrehzahl erhöht werden muss und somit die Druckpulsation verringert wird.In a preferred embodiment, the Bypass line via a pressure relief valve with a Tank connected so that the maximum storage pressure through limits the value set on the pressure relief valve is. Another advantage of this variant according to the invention is that through that about that Flow control valve and that to a low value set pressure relief valve or via the Pressure reducing fluid flowing out the pump speed must be increased and thus the Pressure pulsation is reduced.

Um beispielsweise beim Einfahren des Zylinders ein Entleeren des Hydrospeichers über die Bypassleitung zu verhindern, kann in dieser ein in Richtung zur Speicherleitung öffnendes Rückschlagventil vorgesehen werden.For example, when entering the cylinder Drain the hydraulic accumulator via the bypass line can prevent in this one towards the storage line opening check valve are provided.

Prinzipiell kann diese Bypassleitung auch in den Kolben des Zylinders integriert werden.In principle, this bypass line can also be in the piston of the cylinder can be integrated.

Dem Verbraucher, vorzugsweise dem Zylinder wird bei einem vorteilhaften Ausführungsbeispiel ein Wegmesssensor zugeordnet, über den die Hubposition des Kolbens erfaßt wird und eine entsprechende Ansteuerung der Pumpanordnung und ggfs. der Drosseleinrichtung erfolgt.The consumer, preferably the cylinder, is at an advantageous embodiment, a displacement sensor assigned via which the stroke position of the piston is detected and a corresponding control of the pump arrangement and possibly the throttle device.

Zur Absicherung des Hydrospeichers kann diesem ein Sicherheitsventil vorgeschaltet werden.To secure the hydraulic accumulator, this can be a Safety valve upstream.

Ein weiteres Problem bei den gattungsgemäßen hydraulischen Antrieben besteht darin, dass zum schnellen Ausfahren des Zylinders eine vergleichsweise große Pumpe erforderlich ist. Bei Druckaufbau im Hydrozylinder wird an dieser großen Pumpe ein großes Rückstellmoment erzeugt, so dass der drehzahlvariable Antrieb so ausgelegt werden muß, dass er das entsprechende Drehmoment aufbringen kann. Derartige starke Elektromotoren sind sehr teuer und beanspruchen ein erhebliches Bauvolumen. Desweiteren sind die Verluste bei derart starken Elektromotoren relativ groß, so dass man bestrebt ist, möglichst kleine Motoren einzusetzen. Um diesen gegensätzlichen Anforderungen (schnelle Ausfahrbewegung - starker Elektromotor, große Pumpe; kompakte, billige Bauweise und geringe Verlustleistung - kleiner Motor) zu genügen, kann bei dem hydraulischen Antrieb eine Pumpanordnung verwendet werden, die zwei miteinander gekoppelte Pumpen mit unterschiedlichen Hubvolumina hat. Im Hochdruckbereich wirkt nur die kleinere Pumpe, so dass die Verluste verringert und ein vergleichsweise kleiner drehzahlvariabler Antrieb einsetzbar ist. Zum schnellen Ausfahren und zum Druckaufbau wirken beide Pumpen parallel.Another problem with the generic hydraulic Drives is that for quick Extending the cylinder of a comparatively large pump is required. When pressure builds up in the hydraulic cylinder generates a large restoring torque on this large pump, so that the variable speed drive is designed must be that he apply the appropriate torque can. Such strong electric motors are very expensive and take up a considerable amount of space. Furthermore are the losses with such powerful electric motors relatively large, so that you endeavor to be as small as possible Motors. To meet these conflicting requirements (rapid extension movement - strong electric motor, large pump; compact, cheap design and small Power dissipation - small motor) can suffice with the hydraulic drive uses a pump arrangement be the two coupled pumps with different Stroke volume. Works in the high pressure range only the smaller pump, so the losses are reduced and a comparatively small variable-speed drive can be used. For quick exits and for Both pumps build up pressure in parallel.

Dies wird bei einer vorteilhaften Variante durch eine Ventilanordnung erreicht, über die bei geringem Verbraucherdruck beide Pumpen mit den Verbraucher verbunden sind und bei Erreichen eines Schwelldruckes die Pumpe mit dem größeren Hubvolumen auf drucklosen Umlauf oder dergleichen geschaltet wird, so dass nur noch die kleinere Pumpe wirksam ist.In an advantageous variant, this is achieved by a Valve arrangement achieved via the at low consumer pressure both pumps are connected to the consumer and when a threshold pressure is reached, the pump with the larger stroke volume on pressureless circulation or the same is switched so that only the smaller pump is effective.

Die Verwendung von Pumpanordnungen mit zwei unterschiedlich großen Pumpen ist per se bereits aus der DE 35 24 790 A1 und der DE 197 15 157 A1 bekannt. Bei der erstgenannten Lösung ist die kleinere Pumpe jedoch alleine zur Versorgung eines Hochdruckverbrauchers vorgesehen, während beide Pumpen gemeinsam einen anderen, mit geringerem Druck arbeitenden Verbraucher versorgen. Bei der in der DE 197 15 157 A1 offenbarten Lösung ist eine der Pumpen eine Verstellpumpe, so dass ein entsprechend hoher vorrichtungstechnischer Aufwand erforderlich ist. Keine der beiden vorgenannten Lösungen offenbart die Verwendung von zwei unterschiedlich großen Konstantpumpen in Verbindung mit einem drehzahlvariablen Antrieb. The use of two different pump arrangements large pumps is already out of the DE 35 24 790 A1 and DE 197 15 157 A1 are known. In the The first solution is the smaller pump intended solely to supply a high pressure consumer, while both pumps together another, with supply lower working consumers. at the solution disclosed in DE 197 15 157 A1 is one the pumps have a variable displacement pump, so a corresponding high expenditure on device technology is required. Neither of the two aforementioned solutions discloses the Use of two different sized constant pumps in connection with a variable speed drive.

Für die Pumpen der Pumpanordnung werden vorzugsweise Innenzahnradpumpen verwendet.For the pumps of the pump arrangement are preferred Internal gear pumps used.

Der erfindungsgemäße hydraulische Antrieb läßt sich besonders vorteilhaft für einen Biegezylinder einer Biegepresse einsetzen.The hydraulic drive according to the invention can be particularly advantageous for a bending cylinder Insert bending press.

Ein bevorzugtes Ausführungsbeispiel der Erfindung wird im folgenden anhand schematischer Zeichnungen näher erläutert.A preferred embodiment of the invention is in the following with the help of schematic drawings explained.

Die einzige Figur zeigt ein Schaltschema eines erfindungsgemäßen hydraulischen Antriebs für eine Biegepresse.The single figure shows a circuit diagram of an inventive hydraulic drive for a bending press.

Eine Biegepresse 1 hat einen doppeltwirkend ausgeführten Biegezylinder 2, über den ein auf einem Maschinenbett aufgespanntes Werkstück 4 mit der zum Biegen erforderlichen Kraft beaufschlagbar ist. Dem Biegezylinder 2 ist ein als offener Kreislauf ausgeführter hydraulischer Antrieb mit einer Pumpanordnung 6 und einem Hydrospeicher 8 zugeordnet. Mittels der Pumpanordnung 6 kann Druckmittel aus einem Tank T angesaugt und über eine Druckleitung 10 in einen bodenseitigen Zylinderraum 12 des Biegezylinders 2 gefördert werden. Der Hydrospeicher 8 ist über eine Speicherleitung 14 mit einem kolbenstangenseitigen Ringraum 16 des Biegezylinders 2 verbunden. Die Pumpanordnung 6 hat einen drehzahlvariablen Antrieb 18, so dass zum Ausfahren des Biegezylinders 2 zum Werkstück 4 hin Druckmittel aus dem Tank T über die Pumpanordnung 6, die Druckleitung 10 in den Zylinderraum 12 gefördert wird. Diesem in Ausfahrrichtung wirksamen Druck wirkt der dem Druck im Hydrospeicher 8 entsprechende Druck im Ringraum 16 entgegen. Zum Einfahren des Biegezylinders 2 wird die Drehrichtung der Pumpanordnung 6 über den drehzahlvariablen Antrieb 18 umgekehrt, so dass Druckmittel aus dem Zylinderraum 12 über die Pumpanordnung 6 zum Tank abströmt. Der Druck im Hydrospeicher 8 wirkt dann in Einfahrrichtung, so dass der Kolben des Biegezylinders 2 eingefahren wird. Bei diesem Einfahren wirkt die Pumpanordnung 6 als Motor, so dass entsprechend der Antrieb 18, beispielsweise ein Asynchronmotor, als Generator wirkt.A bending press 1 has a double-acting design Bending cylinder 2, one over a machine bed clamped workpiece 4 with the one for bending required force can be applied. The bending cylinder 2 is an open circuit hydraulic drive with a pump arrangement 6 and a Hydraulic accumulator 8 assigned. By means of the pump arrangement 6 can be drawn from a tank T and via a pressure medium Pressure line 10 in a bottom-side cylinder space 12 of the bending cylinder 2 are promoted. The hydraulic accumulator 8 is via a storage line 14 with a piston rod side Annulus 16 of the bending cylinder 2 connected. The pump arrangement 6 has a variable-speed drive 18, so that to extend the bending cylinder 2 to the workpiece 4 out pressure medium from the tank T via the pump arrangement 6, the pressure line 10 into the cylinder space 12 is promoted. This effective pressure in the direction of extension acts the pressure in the hydraulic accumulator 8 corresponding Pressure in the annular space 16 counter. To retract the bending cylinder 2, the direction of rotation of the pump assembly 6 over the variable-speed drive 18 reversed, so that Pressure medium from the cylinder chamber 12 via the pump arrangement 6 flows out to the tank. The pressure in the hydraulic accumulator 8 then acts in the retracting direction so that the piston of the Bending cylinder 2 is retracted. At this run-in the pump arrangement 6 acts as a motor, so that accordingly the drive 18, for example an asynchronous motor, as Generator works.

Die Hubposition des Biegezylinders 2 wird über einen Wegmesssensor 20 erfaßt, so dass in Abhängigkeit von dessen Signal die Ansteuerung des Antriebs 18 erfolgen kann.The stroke position of the bending cylinder 2 is via a Displacement sensor 20 detects, so that depending on whose signal the control of the drive 18 take place can.

Die vorbeschriebenen Bauelemente sind im Prinzip auch bei den Lösungen vorhanden, die in der Beschreibungseinleitung beschrieben sind.In principle, the components described above are also with the solutions available in the introduction to the description are described.

Eine Besonderheit der erfindungsgemäßen Lösung besteht darin, dass bei dem in der Figur dargestellten Ausführungsbeispiel die Speicherleitung 14 und die Druckleitung 10 über eine Bypassleitung 22 miteinander verbunden sind. In dieser Bypassleitung ist eine verstellbare Drosseleinrichtung 24 angeordnet. Die Bypassleitung 22 ist desweiteren über ein Druckbegrenzungsventil 26 mit dem Tank T verbunden. Über das Druckbegrenzungsventil 26 wird der Druck im Hydrospeicher 8 auf einen vorbestimmten, vergleichsweise geringen Grenzwert eingestellt. In der Bypassleitung 22 ist desweiteren noch ein Rückschlagventil 28 vorgesehen, das in Richtung zur Speicherleitung 14 öffnet. Dieses Rückschlagventil 28 verhindert, dass beim Einfahren des Biegezylinders 2 Druckmittel vom Ringraum 16 bzw. vom Hydrospeicher 8 in die Druckleitung 10 einströmt und somit der Hydrospeicher 8 entladen wird - in diesem Fall würde der Biegezylinder 2 stehen bleiben bzw. dessen Rückstellbewegung verlangsamt. There is a special feature of the solution according to the invention in that the one shown in the figure Embodiment of the memory line 14 and the pressure line 10 connected to one another via a bypass line 22 are. There is an adjustable one in this bypass line Throttle device 24 arranged. The bypass line 22 is also with a pressure relief valve 26 connected to the tank T. Via the pressure relief valve 26 the pressure in the hydraulic accumulator 8 to one predetermined, comparatively low limit set. In the bypass line 22 is also still a check valve 28 is provided which in the direction of Storage line 14 opens. This check valve 28 prevents that when the bending cylinder is retracted 2 Pressure medium from the annular space 16 or from the hydraulic accumulator 8 in the pressure line 10 flows in and thus the hydraulic accumulator 8 is discharged - in this case, the bending cylinder 2 stop or its return movement slowed down.

Anstelle der Drosseleinrichtung 24 kann in der Bypassleitung 22 auch ein Stromregelventil (nicht gezeigt) vorgesehen werden, über das der der Speicherleitung 14 zufließende Druckmittelvolumenstrom unabhängig von der Druckdifferenz in der Druckleitung 10 und in der Speicherleitung 14 ist.Instead of the throttle device 24 can in the Bypass line 22 also a flow control valve (not shown) are provided, via which the Storage line 14 inflowing pressure medium volume flow regardless of the pressure difference in the pressure line 10 and is in memory line 14.

Eine weitere Alternativlösung kann bei bestimmten Anwendungen darin bestehen, die Drosseleinrichtung 24 und ggf. das Druckbegrenzungsventil 26 durch ein Druckminderventil zu ersetzen. Durch dieses Ventil wird der Druck in der Speicherleitung 14 (Sekundärdruck) konstant gehalten, wobei das Ventil bei steigendem Druck in der Speicherleitung zunehmend schließt und schließlich nur noch Leckageverluste in der Speicherleitung ausgleicht.Another alternative solution may be for certain Applications include throttle 24 and if necessary, the pressure relief valve 26 by a Replace pressure reducing valve. Through this valve the pressure in the storage line 14 (secondary pressure) kept constant, with the valve increasing pressure in the storage line increasingly closes and eventually only leakage losses in the storage line balances.

Bei dem dargestellten Ausführungsbeispiel ist dem Hydrospeicher 8 ein Sicherheitsventil 30 vorgeschaltet. Durch geeignete Einstellung des Öffnungsquerschnitts der Drosseleinrichtung 22 kann auch im Betrieb der Biegepresse ein Druckmittelstrom zum Aufladen des Hydrospeichers 8 von der Druckleitung 10 abgezweigt werden, so dass sichergestellt ist, dass dieser stets auf den vorbestimmten Grenzwert aufgeladen ist. Da das Druckbegrenzungsventil 26 bei Erreichen dieses Grenzwerts öffnet und somit ein geringer Druckmittelstrom über die Bypassleitung 22 zum Tank T hin entsteht, muß die Pumpanordnung 6 mit etwas höherer Drehzahl betrieben werden, als dies bei den erfindungsgemäßen Lösungen ohne Bypassleitung der Fall ist. Durch diese Drehzahlerhöhung wird eine Druckpulsation der Pumpe verringert, so dass eine gleichmäßige Ausfahrbewegung des Biegezylinders 2 gewährleistet ist. In the illustrated embodiment, the hydraulic accumulator 8 preceded a safety valve 30. By suitable adjustment of the opening cross section of the Throttle device 22 can also be in operation Bending press a flow of pressure medium for charging the Hydraulic accumulator 8 branched off from the pressure line 10 so that it is ensured that this is always on the predetermined limit is charged. Since that Pressure relief valve 26 when this limit is reached opens and thus a low pressure medium flow over the Bypass line 22 to tank T arises, the Pump arrangement 6 operated at a slightly higher speed be than this in the solutions according to the invention without Bypass line is the case. Through this speed increase pressure pulsation of the pump is reduced so that a smooth extension movement of the bending cylinder 2 is guaranteed.

Eine weitere Besonderheit des in der Figur dargestellten hydraulischen Antrieb besteht darin, dass die Pumpanordnung 6 aus zwei miteinander gekoppelten Pumpen besteht, die jeweils als Konstantpumpe ausgeführt sind. Die in der Figur linke Pumpe, im folgenden kleine Pumpe 30 genannt, ist mit einem vergleichsweise geringen Hubvolumen ausgeführt, während die andere, große Pumpe 32 mit einem vergleichsweise großem Hubvolumen ausgeführt ist. Beide Pumpen 30, 32 sind miteinander gekoppelt und werden von dem drehzahlvariablen Antrieb 18 angetrieben. Der Druckanschluß der kleinen Pumpe 30 ist über eine Hochdruckpumpenleitung 34 mit der Druckleitung 10 verbunden. In dieser Hochdruckpumpenleitung 34 ist ein Pumpen-Druckbegrenzungsventil 36 angeordnet, dass bei Überschreiten eines Maximaldrucks in der Hochdruckpumpenleitung 34 eine Verbindung zum Tank T hin aufsteuert, so dass der von der kleinen Pumpe 30 gelieferte Druck auf diesen Maximalwert begrenzt ist. Von der Hochdruckpumpenleitung 34 zweigt desweiteren eine Nachsaugleitung 38 ab, in der eine in Richtung zum Tank T hin schliessende Rückschlagventil 40 angeordnet ist.Another peculiarity of that shown in the figure hydraulic drive is that the Pump arrangement 6 from two pumps coupled together exists, which are each designed as a constant pump. The left pump in the figure, in the following small pump 30 is called, with a comparatively low Stroke volume while the other, large pump 32 executed with a comparatively large stroke volume is. Both pumps 30, 32 are coupled and are driven by the variable-speed drive 18. The pressure connection of the small pump 30 is via a High pressure pump line 34 with the pressure line 10 connected. In this high pressure pump line 34 is a Pump pressure relief valve 36 arranged that at Exceeding a maximum pressure in the High-pressure pump line 34 connects to tank T. turns on, so that from the small pump 30 delivered pressure is limited to this maximum value. Of the high-pressure pump line 34 branches further one Nachsaugleitung 38 from one in the direction of the tank T non-return valve 40 is arranged.

Die große Pumpe 32 ist über eine Niederdruckpumpenleitung 42 und ein Schaltventil 44 mit der Druckleitung 10 verbunden. Dieses Schaltventil 44 öffnet in seiner federvorgespannten Grundposition die Verbindung zwischen der Niederdruckpumpenleitung 42 und der Druckleitung 10. Eine entgegen der Kraft einer Feder 46 wirkende Steuerfläche des Schaltventils 44 wird über eine Steuerleitung 48 mit dem Druck in der Druckleitung 10 beaufschlagt. Bei Ansteigen des Drucks in der Druckleitung 10 auf einen vorbestimmten Schwellwert, wird das Schaltventil 44 in eine Schaltposition umgeschaltet, in der die Niederdruckpumpenleitung 42 mit dem Tank T verbunden ist - die große Pumpe 32 ist dann auch drucklosen Umlauf geschaltet. Ähnlich wie bei der kleinen Pumpe 30 wird der Druck der großen Pumpe 32 über ein weiteres Pumpen-Druckbegrenzungsventil 50 auf einen Maximalwert begrenzt. Von der Niederdruckpumpenleitung 42 zweigt eine weitere Nachsaugleitung 52 mit Rückschlagventil 54 ab.The large pump 32 is via a low pressure pump line 42 and a switching valve 44 with the pressure line 10 connected. This switching valve 44 opens in its spring-loaded basic position the connection between the low pressure pump line 42 and the pressure line 10. A control surface acting against the force of a spring 46 of the switching valve 44 is via a control line 48 pressurized in the pressure line 10. at Rise of the pressure in the pressure line 10 to one predetermined threshold, the switching valve 44 in switched a switching position in which the low pressure pump line 42 is connected to the tank T - the big one Pump 32 is then also switched to pressureless circulation. Similar to the small pump 30, the pressure of the large pump 32 via another pump pressure relief valve 50 limited to a maximum value. Of the Low-pressure pump line 42 branches another suction line 52 with check valve 54.

Zu Beginn der Ausfahrbewegung des Biegezylinders 2 werden beide Pumpen 30, 32 vom drehzahlvariablen Antrieb 18 angetrieben. Das Schaltventil 44 befindet sich in seiner Grundposition, so dass die Druckmittelströme beider Pumpen 30, 32 addiert und über die Druckleitung 10 in den Zylinderraum 12 gefördert werden. Der Biegezylinder 2 fährt mit vergleichweise hoher Geschwindigkeit aus und im Zylinderraum 12 baut sich ein entsprechender Druck auf. Bei Erreichen des Schwelldrucks in der Druckleitung 10 wird das Schaltventil 44 in seine zweite Schaltposition umgeschaltet, so dass die Niederdruckpumpenleitung 42 mit dem Tank T verbunden ist. Ab diesem Schwelldruck fördert nur noch die kleine Pumpe 30 Druckmittel zum Biegezylinder 2. D.h., zum Halten der Hubposition des Biegezylinders 2 und zum Aufbau der Maximaldrücke wird lediglich die kleinere Pumpe 30 verwendet, so dass das bei derart hohen Drücken, auf die Pumpe wirkende Rückstellmoment vergleichsweise gering ist und entsprechend der Antrieb 18 mit geringerem Drehmoment ausgelegt werden kann.At the beginning of the extension movement of the bending cylinder 2 both pumps 30, 32 from the variable-speed drive 18 driven. The switching valve 44 is in its basic position so that the pressure medium flows both pumps 30, 32 added and via the pressure line 10 are conveyed into the cylinder chamber 12. The Bending cylinder 2 runs with a comparatively high Speed off and builds up in the cylinder chamber 12 appropriate pressure on. When the threshold pressure is reached in the pressure line 10, the switching valve 44 is in its second switching position switched so that the Low pressure pump line 42 is connected to the tank T. From this threshold pressure, only the small pump delivers 30 pressure medium to the bending cylinder 2nd i.e. to hold the Stroke position of the bending cylinder 2 and to build the Only the smaller pump 30 becomes the maximum pressure used so that at such high pressures on the Pump acting restoring torque is comparatively low and correspondingly the drive 18 with a lower torque can be interpreted.

Die Anmelderin behält sich vor, die beiden von einem drehzahlvariablen Antrieb angetriebenen Pumpen mit unterschiedlichen Hubvoluminas zum Gegenstand einer Teilanmeldung zu machen.The applicant reserves the right to do the two of one variable speed drive with driven pumps different stroke volumes to the subject of a Make divisional registration.

Beim vorbeschriebenen Ausführungsbeispiel ist die Bypassleitung 22 mit der dazugehörigen Ventilanordnung als eigenständiges Bauelement ausgeführt. Prinzipiell ist es auch möglich diese Bypassleitugng 22 in den Hydrozylinder 2 zu integrieren. Dabei kann die Bypassleitung 22 beispielsweise den Kolben durchsetzen, so dass durch diese Bypassleitung mit der integrierten Drossel (24) der Zylinderraum (12) und der Ringraum (16) verbunden sind.In the above-described embodiment, the Bypass line 22 with the associated valve arrangement executed as an independent component. In principle is it is also possible to bypass this 22 in the Integrate hydraulic cylinder 2. The Bypass line 22, for example, push the piston through, so that through this bypass line with the integrated Throttle (24) the cylinder space (12) and the annular space (16) are connected.

Offenbart ist ein hydraulischer Antrieb für einen Verbraucher, vorzugsweise für einen doppeltwirkenden Zylinder, dessen einer Druckraum über eine Pumpanordnung mit drehzahlvariablen Antrieb mit Druckmittel versorgbar ist, während ein in Gegenrichtung wirksamer Druckraum mit dem Druck eines Hydrospeichers beaufschlagt ist. Zum Aufladen des Hydrospeichers kann Druckmittel über eine Bypassleitung und ein Stromventil oder ein Druckminderventil von dem von der Pumpanordnung geförderten Druckmittelstrom abgezweigt werden, so dass ein Aufladen auch während des Betriebs des oder der Verbraucher möglich ist. Die Anmeldung offenbart desweiteren eine Pumpanordnung, bei der zwei Pumpen mit unterschiedlichen Hubvolumina von einem gemeinsamen drehzahlvariablen Antrieb angetrieben werden, wobei bei hohen Drücken am Verbraucher nur noch die Pumpe mit geringerem Hubvolumen wirksam ist, so dass der Antrieb mit vergleichsweise kleinem Drehmoment ausgelegt werden kann. A hydraulic drive for one is disclosed Consumer, preferably for a double-acting Cylinder, one of which is a pressure chamber via a pump arrangement can be supplied with pressure medium with variable-speed drive is, while a pressure chamber effective in the opposite direction with the pressure of a hydraulic accumulator is applied. To the The hydraulic accumulator can be charged via a pressure medium Bypass line and a flow valve or a Pressure reducing valve from that of the pump assembly conveyed pressure medium flow are branched off, so that charging even while the or Consumer is possible. The application discloses furthermore a pump arrangement in which two pumps with different stroke volumes from a common one variable-speed drive are driven, with high pressures on the consumer only with the pump lower displacement is effective, so the drive can be designed with comparatively small torque can.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

11
Biegepressebending press
22
Biegezylinderbending cylinders
44
Werkstückworkpiece
66
Pumpanordnungpump assembly
88th
Hydrospeicherhydraulic accumulator
1010
Druckleitungpressure line
1212
Zylinderraumcylinder space
1414
Speicherleitungstorage line
1616
Ringraumannulus
1818
Antriebdrive
2020
WegmesssensorDisplacement
2222
Bypassleitungbypass line
2424
Drosseleinrichtungthrottling device
2626
DruckbegrenzungsventilPressure relief valve
2828
Rückschlagventilcheck valve
3030
kleine Pumpesmall pump
3232
große Pumpelarge pump
3434
HochdruckpumpenleitungHigh-pressure pump line
3636
Pumpen-DruckbegrenzungsventilPump pressure relief valve
3838
Nachsaugleitungsubsequent suction
4040
Rückschlagventilcheck valve
4242
NiederdruckpumpenleitungLow-pressure pump line
4444
Schaltventilswitching valve
4646
Federfeather
4848
Steuerleitungcontrol line
5050
weiteres Pumpen-Druckbegrenzungsventilanother pump pressure relief valve
5252
weitere Nachsaugleitungfurther suction line
5454
Rückschlagventilcheck valve

Claims (12)

Hydraulischer Antrieb für einen Verbraucher (2) mit zwei entgegengesetzt wirkenden Druckräumen (12, 16) von denen einer über eine Druckleitung (10) und eine Pumpanordnung (16) mit drehzahlvariablem Antrieb (18) und der andere über eine Speicherleitung (14) und einen Hydrospeicher (8) mit Druckmittel versorgbar ist, gekennzeichnet durch eine die Druckleitung (10) mit der Speicherleitung (14) verbindende Bypassleitung (22), in der ein Stromventil (24) oder ein Druckminderventil angeordnet ist.Hydraulic drive for a consumer (2) with two oppositely acting pressure chambers (12, 16), one of which via a pressure line (10) and a pump arrangement (16) with variable-speed drive (18) and the other via a storage line (14) and one Hydraulic accumulator (8) can be supplied with pressure medium, characterized by a bypass line (22) connecting the pressure line (10) to the storage line (14), in which a flow valve (24) or a pressure reducing valve is arranged. Hydraulischer Antrieb nach Patentanspruch 1, wobei das Stromventil eine - vorzugsweise verstellbare - Drossel (24) oder ein Stromregelventil ist.Hydraulic drive according to claim 1, wherein the flow valve a - preferably adjustable - Throttle (24) or a flow control valve. Hydraulischer Antrieb nach Patentanspruch 1 oder 2, wobei der Verbraucher ein Zylinder (2) mit einem bodenseitigen Zylinderraum (12) und einen kolbenstangenseitigen Ringraum (16) ist.Hydraulic drive according to claim 1 or 2, the consumer being a cylinder (2) with a bottom-side cylinder space (12) and one piston rod-side annular space (16). Hydraulischer Antrieb nach einem der vorhergehenden Patentansprüche, wobei in der Bypassleitung (22) ein Druckbegrenzungsventil (26) zur Begrenzung des Speicherdrucks angeordnet ist.Hydraulic drive according to one of the preceding Claims, wherein in the bypass line (22) Pressure relief valve (26) to limit the Storage pressure is arranged. Hydraulischer Antrieb nach einem der vorhergehenden Patentansprüche, wobei in der Bypassleitung (22) eine in Richtung zur Speicherleitung (14) öffnendes Rückschlagventil (28) vorgesehen ist.Hydraulic drive according to one of the preceding Claims, wherein in the bypass line (22) opening towards the storage line (14) Check valve (28) is provided. Hydraulischer Antrieb nach einem der vorhergehenden Patentansprüche, wobei dem Hydrospeicher (8) ein Sicherheitsventil (30) vorgeschaltet ist. Hydraulic drive according to one of the preceding Claims, wherein the hydraulic accumulator (8) Safety valve (30) is connected upstream. Hydraulischer Antrieb nach einem der vorhergehenden Patentansprüche 3 bis 6, wobei dem Zylinder (2) ein Wegmesssensor (20) zugeordnet ist.Hydraulic drive according to one of the preceding Claims 3 to 6, wherein the cylinder (2) Displacement sensor (20) is assigned. Hydraulischer Antrieb nach einem der vorhergehenden Patentansprüche, wobei die von einem drehzahlvariablen Antrieb (18) angetriebene Pumpanordnung zwei Pumpen (30, 32) mit unterschiedlichen Hubvolumina hat.Hydraulic drive according to one of the preceding Claims, the one of variable speed drive (18) driven Pump arrangement with two pumps (30, 32) has different stroke volumes. Hydraulischer Antrieb nach Patentanspruch 8, wobei die Pumpen (30, 32) Konstantpumpen sind.Hydraulic drive according to claim 8, wherein the pumps (30, 32) are constant pumps. Hydraulischer Antrieb nach Patentanspruch 8 oder 9, mit einer Ventilanordnung (44) über die bei geringem Verbraucherdruck beide Pumpen (30, 32) mit dem Verbraucher (2) verbunden sind, wobei bei Erreichen eines Schwelldrucks am Verbraucher (2) nur die Pumpe (30) mit kleinerem Hubvolumen mit dem Verbraucher (2) verbunden ist.Hydraulic drive according to claim 8 or 9, with a valve arrangement (44) over which at low Consumer pressure both pumps (30, 32) with the Consumers (2) are connected, when reached of a threshold pressure at the consumer (2) only the pump (30) with a smaller stroke volume with the consumer (2) connected is. Hydraulischer Antrieb nach Patentanspruch 9, wobei die Pumpen (30, 32) Innenzahnradpumpen sind.Hydraulic drive according to claim 9, wherein the pumps (30, 32) are internal gear pumps. Hydraulischer Antrieb nach einem der Patentansprüche 3 bis 11, wobei der Zylinder ein Biegezylinder (2) einer Biegepresse (1) ist.Hydraulic drive according to one of the claims 3 to 11, the cylinder being a bending cylinder (2) a bending press (1).
EP20030015768 2002-08-02 2003-07-10 Hydraulic drive Expired - Lifetime EP1387090B1 (en)

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ITMO20080243A1 (en) * 2008-09-23 2010-03-24 Interpump Hydraulics Spa DISTRIBUTION DEVICE FOR HYDRAULIC CIRCUITS.
WO2011021986A1 (en) * 2009-08-18 2011-02-24 Demirer Teknolojik Sistemler Sanayi Ticaret Limited Sirketi Energy saving in hydraulic bending presses
WO2012055579A1 (en) 2010-10-27 2012-05-03 Coskunöz Metal Form Makina Endüstri Ve Tic. A.S. A servo hydraulic press
DE102011108285A1 (en) 2010-12-22 2012-06-28 Robert Bosch Gmbh Hydraulic drive
WO2012112130A1 (en) 2011-02-16 2012-08-23 Ermaksan Miki̇na Sanayi̇ Ve Ti̇caret Anoni̇m Şi̇rketi̇ A press brake having low noise level with energy savings
CN104854353A (en) * 2012-11-22 2015-08-19 Hydac系统有限公司 Turbine valve actuator
WO2015185179A1 (en) * 2014-06-03 2015-12-10 Liebherr-Aerospace Lindenberg Gmbh Electrically driven motor-pump unit
CN105673596A (en) * 2016-04-05 2016-06-15 广东精铟海洋工程股份有限公司 Double hydraulic control system with automatic pressure-maintaining function and test method of double hydraulic control system
CN103261706B (en) * 2010-12-22 2016-11-30 罗伯特·博世有限公司 Fluid pressure drive device
CN110848181A (en) * 2019-10-18 2020-02-28 中联重科股份有限公司 Hydraulic transmission system and crane

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US4633665A (en) * 1983-08-25 1987-01-06 Bueter Josef Double-action piston/cylinder unit
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Cited By (19)

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US8215108B2 (en) 2005-09-12 2012-07-10 Laeis Gmbh Control apparatus and control method for a piston/cylinder arrangement
JP2009508060A (en) * 2005-09-12 2009-02-26 ラーイース ゲゼルシャフト ミット ベシュレンクテル ハフツング Control device and control method for piston / cylinder mechanism
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WO2007031163A1 (en) * 2005-09-12 2007-03-22 Laeis Gmbh Control apparatus and control method for a piston/cylinder arrangement
ITMO20080243A1 (en) * 2008-09-23 2010-03-24 Interpump Hydraulics Spa DISTRIBUTION DEVICE FOR HYDRAULIC CIRCUITS.
EP2165878A1 (en) 2008-09-23 2010-03-24 Interpump Hydraulics S.p.A. A directional control device for hydraulic circuits
WO2011021986A1 (en) * 2009-08-18 2011-02-24 Demirer Teknolojik Sistemler Sanayi Ticaret Limited Sirketi Energy saving in hydraulic bending presses
WO2012055579A1 (en) 2010-10-27 2012-05-03 Coskunöz Metal Form Makina Endüstri Ve Tic. A.S. A servo hydraulic press
DE102011108285A1 (en) 2010-12-22 2012-06-28 Robert Bosch Gmbh Hydraulic drive
WO2012084093A1 (en) 2010-12-22 2012-06-28 Robert Bosch Gmbh Hydraulic drive
CN103261706A (en) * 2010-12-22 2013-08-21 罗伯特·博世有限公司 Hydraulic driver
CN103261706B (en) * 2010-12-22 2016-11-30 罗伯特·博世有限公司 Fluid pressure drive device
WO2012112130A1 (en) 2011-02-16 2012-08-23 Ermaksan Miki̇na Sanayi̇ Ve Ti̇caret Anoni̇m Şi̇rketi̇ A press brake having low noise level with energy savings
CN104854353A (en) * 2012-11-22 2015-08-19 Hydac系统有限公司 Turbine valve actuator
WO2015185179A1 (en) * 2014-06-03 2015-12-10 Liebherr-Aerospace Lindenberg Gmbh Electrically driven motor-pump unit
CN105673596A (en) * 2016-04-05 2016-06-15 广东精铟海洋工程股份有限公司 Double hydraulic control system with automatic pressure-maintaining function and test method of double hydraulic control system
CN105673596B (en) * 2016-04-05 2017-05-10 广东精铟海洋工程股份有限公司 Double hydraulic control system with automatic pressure-maintaining function and test method of double hydraulic control system
CN110848181A (en) * 2019-10-18 2020-02-28 中联重科股份有限公司 Hydraulic transmission system and crane

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