Classifications

• • 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
  • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
  • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
  • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/2221—Control of flow rate; Load sensing arrangements
  • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/20—Drives; Control devices
  • E02F9/22—Hydraulic or pneumatic drives
  • E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• • 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
  • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
• • 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
  • F15B2211/30—Directional control
  • F15B2211/305—Directional control characterised by the type of valves
  • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
  • F15B2211/3053—In combination with a pressure compensating valve
  • F15B2211/30555—Inlet and outlet of the pressure compensating valve being connected to the 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
  • F15B2211/30—Directional control
  • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
  • F15B2211/31523—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member
  • F15B2211/31541—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source and an output member having a single pressure source and multiple 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
  • F15B2211/30—Directional control
  • F15B2211/32—Directional control characterised by the type of actuation
  • F15B2211/321—Directional control characterised by the type of actuation mechanically
  • F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
• • 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
  • F15B2211/32—Directional control characterised by the type of actuation
  • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
• • 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
  • F15B2211/35—Directional control combined with flow control
  • F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
• • 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
  • F15B2211/41563—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a 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
  • F15B2211/40—Flow control
  • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line

Definitions

• the invention relates to a hydraulic control arrangement for load-independent control of a consumer according to the preamble of claim 1.
• Mobile tools such as mini excavators and compact excavators, are increasingly being equipped with hydraulic control systems that distribute the pressure medium volume flow of a single pump to the connected consumers regardless of the load.
• These consumers are controlled, for example, via an LUDV control block, which has a large number of valve disks assigned to each of the consumers.
• a continuously adjustable directional control valve is accommodated in each valve disc, to which a pressure-compensating LUDV pressure compensator is assigned.
• the pressure medium flowing to the consumer first flows through a metering orifice formed by the continuously adjustable directional valve and then through the pressure compensator.
• the control piston of this pressure compensator is acted upon on its front side by the pressure prevailing between the metering orifice and the pressure compensator.
• this pressure is reduced by the pressure drop across the metering orifice, which is largely independent of the load pressure and pump pressure.
• the control piston of the pressure compensator is acted upon by the highest load pressure of all hydraulic consumers operated at the same time. This means that the highest load pressure also prevails between the metering orifice and the pressure compensator and that the partial pressure medium flows to all hydraulic consumers actuated at the same time are independent of the individual load pressures of the Consumers are reduced in the same ratio if the maximum delivery rate of the assigned pump is reached when the opening cross sections of the metering orifice are enlarged.
• US Pat. No. 6,526,747 B2 discloses a solution in which the hydraulically and mechanically actuated functions are locked in that the LUDV pressure compensators are acted upon by the pump pressure in the closing direction and thus shut off the pressure medium supply to the consumer.
• this pump pressure acts via a directional valve in the load pressure line of the control block common to all consumers, which is actuated via a shut-off valve, the pressure in the control oil supply being used to switch over the directional valve.
• Such a solution requires a considerable amount of circuitry.
• the invention has for its object to provide a hydraulic control arrangement in which the locking of the mechanically operated consumers is simplified.
• the LUDV pressure compensators assigned to the mechanically operated directional control valves are acted upon by a spring which acts in the closing direction.
• the load pressure signaling line which is common to all consumers, is connected to the tank via a current regulator, so that a small amount of control oil always flows out to the tank.
• a safety valve is arranged in this load pressure line, via which the connection of the load pressure signaling line to the current regulator can be shut off.
• a region upstream of the switching valve is connected via a nozzle to a section of the pressure medium flow path between the pump and the LUDV pressure compensator.
• the safety valve When the safety valve is switched to a blocking position, the connection of the load pressure signal line to the tank is blocked and the pressure tapped via the nozzle is effective in a rear control room connected to the load pressure signal line, so that the LUDV pressure compensator is brought into its closed position.
• the load pressure signaling line is connected to a pump control downstream of the current regulator. After the load pressure signaling line has been shut off, the control pressure at the pump control also drops towards the tank, so that the pump can only generate the standby pressure.
• the solution according to the invention is characterized by a very simple structure and good response behavior.
• the nozzle arranged upstream of the safety valve is either integrated into the pressure compensator, the pressure applied to the pressure compensator inlet being reported to the rear control chamber via this nozzle, so that the pressure compensator piston is pressure-balanced and is closed by the force of the additional spring ,
• this nozzle is provided in a branch line which extends from an area upstream of the directional valve to an area upstream of the safety valve.
• the pump pressure upstream of the directional control valve is reported to the rear pressure chamber.
• the pump supplying the consumers is designed as a constant pump, to which a differential pressure controller is assigned, which is controlled as a function of the load pressure in the load pressure signaling line.
• a shut-off valve is provided, via which the control oil supply to shut off the hydraulically operated consumers
• Pilot control unit is interrupted, so that Valve spool can be moved back to the spring-loaded basic position.
• the safety valve is then actuated by switching this shut-off valve.
• Figure 1 is a circuit diagram of a control block for a mobile work device with at least one mechanically controllable consumer and
• FIG. 2 shows an enlarged illustration of a valve disk of the control block from FIG. 1.
• FIG. 1 shows a control arrangement of a mobile working device, consumers of the mobile working device, for example a mobile excavator, being controllable via a control block 1 with valve disks 2, 4.
• a consumer for example a hydraulic motor 6 of a travel drive
• a further consumer for example a hydraulic cylinder 8 actuating the boom.
• the pressure medium is supplied to the control block 1 via a constant pump 10, the flow of which is controlled via a differential pressure regulator 12 as a function of the highest load pressure of the actuated consumers.
• This load pressure is a via an LS line 14 in Control direction effective control surface of the differential pressure regulator 12, during which the control surface effective in the opening direction is acted upon by the pump pressure.
• Each of the valve disks 2, 4 has a continuously adjustable directional valve 16, each of which has directional parts 20, 22 and a speed part 18.
• the directional parts 20, 22 control the pressure medium flow to or from the consumer and the speed part 18 determines the pressure medium volume flow, which can be set by opening a metering orifice. Downstream of this metering orifice there is a LUDV pressure compensator 24 which, as described at the beginning, keeps the pressure drop across the metering orifice constant, regardless of the load.
• Each pressure compensator 24 is acted upon in the control position in the direction of opening by the individual load pressure of the associated consumer and in the closing direction by the highest load pressure which is tapped via the LS line 14.
• the directional valve 16 of the valve disc 2 is actuated mechanically, for example via an adjusting lever, while the directional valve 16 of the valve disc 4 is actuated via a pilot control device 26, which in principle consists of pressure reducing valves, at the input of which a control oil supply 28 provided pressure is present and at the output of which a control pressure is generated depending on the adjustment of the pilot device 26, which is applied to actuate the directional control valve 16 to control rooms 31, 33 of the directional control valve 16 of the valve disk 4.
• An electrically operated shut-off valve 30 is provided in the area between the control oil supply 28 and the pilot control device 26, via which the control oil supply 28 can be connected to a tank T. In this shut-off valve 30 is switched over in the operating position, so that the pilot control device 26 is supplied with control oil.
• the area downstream of the shut-off valve 30 is connected via a control line 32 to a control chamber of a safety valve 34, which is designed as a 2/2 way valve.
• the safety valve 34 is biased by a spring into a switching position in which the LS line 14 is shut off.
• the control oil supply pressure provided by the control oil supply 28 acts in the control chamber of the safety valve 34, so that the latter is brought into a passage position against the force of the spring.
• a current regulator 36 is arranged, via which the LS line 14 is connected to the tank T. That through the LS line in the open position of the safety valve 34, a constant control oil flow flows out to the tank T, the size of which depends on the setting of the flow control valve 36.
• the pressure in the LS line 14 is limited by a pressure relief valve 37, which is arranged between the flow control valve 36 and the safety valve 34.
• valve disc 2 A structure of the valve disc 2 is explained below with reference to the enlarged representation in Figure 2.
• Each of the valve disks 2, 4 described above has a pressure connection P at which the pump pressure is present, a tank connection S connected to the tank, an LS connection LS connected to the LS line 14, and two working connections A, B connected to the consumer, in the present case the hydraulic motor 6
• a valve spool 38 of the directional control valve 16 of the valve disk 2 is prestressed into its illustrated basic position via a centering spring arrangement 40.
• the valve slide 38 is actuated via an actuating section 42 protruding laterally from the valve disk 2, to which an adjusting lever or the like can be articulated.
• valve spool 38 is guided in a valve bore 44, which in the radial direction leads to a pressure chamber 46, an inlet chamber 48, two discharge chambers 50, 52 arranged approximately symmetrically to the pressure chamber 20, two working chambers 54, 56 arranged on both sides thereof, and to two adjacent tank chambers 58, 60 is expanded.
• the valve slide 16 has a central measuring orifice collar 62 which, together with the remaining ring web between the pressure chamber 46 and the inlet chamber 48, determines a measuring orifice forming the speed part 18.
• Two control collars 64, 66 and two tank collars 68, 70 of the directional part 20, 22 are arranged on the valve slide 38 on both sides of this measuring orifice collar 62.
• the pressure chamber 46 is connected to the pressure port P and the two tank chambers 58, 60 are connected to the tank port S.
• the inlet chamber 48 is connected to the inlet of the pressure compensator 24 via an inlet channel 72. Their output is connected via two drain channels 74, 76 to the drain chamber 50, 52 and the two working chambers 54, 56 via working channels 78, 80 to the working connection A and B, respectively.
• the pressure compensator 24 is shown in its closed position. It has a pressure compensator piston 84 which is guided axially displaceably in a pressure compensator bore 82.
• the pressure compensator piston 84 is designed as a stepped piston, the smaller piston surface being supported on a shoulder 86 of the inlet channel 72 in the closed position.
• the end face of the pressure compensator piston 84 facing this shoulder 86 is acted upon in the control position by the pressure in the outlet channels 74, 76, ie the load pressure at the associated consumer.
• the larger diameter (at the top in FIG. 2) of the pressure compensator piston 84 plunges into a rear control chamber 88, which is connected to the LS connection via an LS channel 90.
• the pressure compensator piston 84 has an axial bore 92 opening into the stepped-down end face, which bores via a load signaling nozzle 94 in one of the pressure compensator pistons
• Transverse bore 96 a further nozzle 98 is provided, via which the axial bore 92 is always connected to the control chamber 88.
• the pressure compensator piston 84 is also biased by a spring 100 against the shoulder 62 into its closed position, in which the outer peripheral edge 102 of the gradation of the pressure compensator piston 84 has controlled the connection between the inlet channel 72 and the outlet channels 74, 76.
• the spring 100 is supported on a screw plug 104 screwed into the pressure compensator bore 82.
• the valve disk 4 assigned to the hydraulic function has in principle the same structure, but the pressure compensator piston 106 is not designed with a nozzle 98 and thus there is no permanent connection between the axial bore 108 and the control chamber 110. Furthermore, the pressure compensator piston 106 is not biased into its closed position by a spring.
• the valve slide 16 When the hydraulic motor 6 is actuated, the valve slide 16 is shifted manually into an open position via the adjusting lever, so that the measuring orifice of the speed section 18 is opened.
• the pump pressure is present at the input of the pressure compensator 24 and acts against the load pressure effective in the closing direction. The pump pressure rises until the pressure compensator piston 84 opens the connection to the outlet channels 74, 76. The pressure medium can then flow via the directional parts 20, 22 to the hydraulic motor 6 and from there back to the tank. If only the hydraulic motor 6 is actuated, the pressure compensator 24 is brought into the fully open position by the load pressure on the hydraulic motor 6, so that this load pressure is reported to the LS line.
• shut-off valve 30 If the driver now wants to leave his driver's position, he must first actuate the shut-off valve 30. This is done for example via a switch or the like. As a result, the control oil supply to the pilot control unit 26 is shut off, so that the directional control valve 16 of the valve disk 4 is moved back into its basic position and accordingly the hydraulic cylinder 8 is no longer activated. By switching the shut-off valve 30, the tank pressure is also present in the control line 32, so that the open one
• Safety valve 34 is brought into its closed position. As a result, the connection between the differential pressure regulator 12 and the individual valve functions is interrupted. The spring space of the differential pressure regulator 12 is relieved towards the tank T via the current regulator 36, so that the differential pressure regulator 12 can only generate the standby pressure.
• Valve disc 2 is interrupted via the axial bore 82, the transverse bore 96, the nozzle 98 and via the LS line 14 and thus there is no longer a pressure drop across the pressure compensator 24 due to this control oil flow, the pressure compensator piston 84 is pressure-balanced and by the force of the spring 100 in its closed position pushed back and thus blocked the connection to the hydraulic motor 6.
• shut-off valve 30 all mechanically actuated functions are thus also locked by actuating the shut-off valve 30.
• actuate the shutoff valve 30 mechanically or electrically.
• the cross section of the nozzle 98 is selected such that, on the one hand, the mechanically actuated ones are securely locked
• Valve disks 2 is enabled, but on the other hand the LUDV function described above is only slightly influenced.
• FIG 1 a variant of the invention is shown, according to which the nozzle 98 'is not arranged in the pressure compensator piston 84 but in a branch line 112, via which the pressure medium flow path downstream of the pump 10 and upstream of the measuring orifice with a section of the LS line 14 upstream of the Safety valve 34 is connected.
• the safety valve 34 In the normal operating state, i.e. When the safety valve 34 is open, a control oil volume flow continuously flows through this nozzle 98 'via the flow regulator 36 to the tank T.
• the safety valve 34 is switched over, the pressure at the outlet of the pump in the load signaling line 14 and thus in the control chamber 88 acts via the nozzle 98 ′, so that the pressure compensator 24 is also returned to its closed position.
• a hydraulic control arrangement for controlling a consumer, with at least one mechanically actuated, continuously adjustable directional valve, which is followed by an LUDV pressure compensator.
• the control arrangement is designed with a spring acting on the pressure compensator piston in a closed position.
• a LS line carrying the highest load pressure of all consumers is connected to a tank via a current regulator, wherein a pump control can also be relieved via the current regulator in order to reduce the delivery volume.
• the LUDV pressure compensator is pressure-balanced via a nozzle, via which a connection is established between the LS line and a section of the pressure medium flow path downstream of the pump and upstream of the outlet of the pressure compensator. This nozzle is preferably integrated in the pressure compensator piston.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mining & Mineral Resources (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Fluid-Pressure Circuits (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=33482509

Family Applications (1)

Country Status (6)

Families Citing this family (10)

Family Cites Families (7)

• 2003
  • 2003-06-04 DE DE10325295A patent/DE10325295A1/de not_active Withdrawn
• 2004
  • 2004-05-28 AT AT04739453T patent/ATE343687T1/de active
  • 2004-05-28 US US10/558,380 patent/US7395662B2/en not_active Expired - Fee Related
  • 2004-05-28 WO PCT/EP2004/005835 patent/WO2004109019A1/fr not_active Ceased
  • 2004-05-28 DE DE502004001862T patent/DE502004001862D1/de not_active Expired - Lifetime
  • 2004-05-28 EP EP04739453A patent/EP1629156B1/fr not_active Expired - Lifetime
  • 2004-05-28 JP JP2006508226A patent/JP5081447B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events