EP0546300B1 - Electrohydraulic control system - Google Patents

Electrohydraulic control system Download PDF

Info

Publication number
EP0546300B1
EP0546300B1 EP92118374A EP92118374A EP0546300B1 EP 0546300 B1 EP0546300 B1 EP 0546300B1 EP 92118374 A EP92118374 A EP 92118374A EP 92118374 A EP92118374 A EP 92118374A EP 0546300 B1 EP0546300 B1 EP 0546300B1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
proportional
control
motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92118374A
Other languages
German (de)
French (fr)
Other versions
EP0546300A1 (en
Inventor
Hartmut Dipl.-Ing. Sandau (Fh)
Uwe Dipl.-Ing. Altmann
Horst Dr. Dr.-Ing. Hesse
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 to DE19914140409 priority Critical patent/DE4140409A1/en
Priority to DE4140409 priority
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0546300A1 publication Critical patent/EP0546300A1/en
Application granted granted Critical
Publication of EP0546300B1 publication Critical patent/EP0546300B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08Servomotor systems incorporating electrically operated control means
    • F15B21/087Control strategy, e.g. with block diagram

Description

    State of the art
  • The invention relates to an electrohydraulic control device for load-compensated control of a hydraulic motor according to the type specified in the preamble of claim 1.
  • Such an electrohydraulic control device for load-compensated control of a hydraulic motor is already known from DE-OS 25 23 600, in which the pressure difference at the inlet and outlet of the proportional valve is measured and the position of the control slide is adjusted with the aid of a control circuit so that the influence the pressure difference dependent on changes in load is compensated so that the volume flow is independent of the applied pressure difference. This is achieved by squaring the pressure difference in the control circuit and dividing the setpoint for the spool stroke or volume flow by the squared value. This output signal is fed to a known position control loop as a setpoint for the valve lift. This control device works with a complex 4-way proportional valve, that is less suitable for mobile applications. In addition, the directional control valve requires a position sensor with position control loop that picks up the slide stroke in order to carry out the electronic load compensation.
  • Furthermore, from DE 39 31 962 A1 control electronics for an electrically adjustable actuator is known, in which the characteristic field of the actuator is written into a table memory in order to achieve a linear control behavior and thus a corrected control signal for the actuator is obtained from a setpoint in a microprocessor . Characteristics can not only be linearized but also changed arbitrarily, so that the flow load function of a valve can also be taken into account at different pressures. The construction of special electrohydraulic control devices is not taught here.
  • Furthermore, from DE 33 47 000 A1 an electrohydraulic control device for a double-acting hydraulic motor is known, in which each motor connection is controlled via an identical proportional throttle valve. Each proportional throttle valve is designed as a 3-way valve in slide valve design, is electro-hydraulically pilot-controlled and is located in a position control loop, so that the volume flows to and from each motor connection can be controlled individually via an electrical control unit, the signals from electro-hydraulic pressure sensors at each motor connection also being able to be supplied to the control unit . With this control device, several additional functions such as differential switching, fail-safe function, force limitation or avoidance of hollow suction are to be fulfilled in a locking cylinder of an injection molding machine. This control device is not intended for load pressure-compensated control of a single-acting motor in mobile applications.
  • Advantages of the invention
  • The electrohydraulic control device according to the invention for load-compensated control of a hydraulic motor with the characterizing features of claim 1 has the advantage that it can be realized with existing components in a relatively simple and inexpensive construction and allows electronic load-compensated control of the hydraulic motor in both directions, i.e. with Raising and lowering. By designing the proportional throttle valve as a seat valve, the leakage can be kept low. In addition, despite the training as a seat valve, sensitive control can be achieved when lifting and lowering. The control device is relatively compact and lightweight and is therefore particularly suitable for use in mobile applications.
  • Advantageous further developments and improvements of the control device specified in claim 1 are possible through the measures listed in the subclaims. Formations according to claims 3 to 6 are particularly advantageous, as a result of which the control device can be implemented in a simple and cost-effective manner from existing components, and in addition to an electronically load-compensated lowering function, parallel control of additional hydraulic consumers is possible, since a pressure-resistant continuity connection via a Pressure compensator is supplied with pressure medium. Furthermore, it is expedient to design the control device according to claims 7 to 9, whereby particularly good fine control properties can be achieved in addition to a simple and space-saving construction. The pressure-controlled orifice plate in conjunction with the pilot-controlled proportional pressure valve controlled by the control electronics allow lifting processes to be controlled sensitively with load pressure compensation. It is also advantageous if the control device is equipped with a double-tight proportional throttle valve, so that an electronically load-compensated lifting and lowering is possible with a single proportional throttle valve of the seat valve type. Furthermore, it is advantageous if the control device is designed in such a way that the proportional throttle valve is connected in the diagonal of a hydraulic rectifier circuit designed as a full bridge. In this way, electronic load compensation for the lifting and lowering functions can be achieved with only one proportional throttle valve, and the effort in the control electronics can also be kept relatively low, since the characteristic field of the proportional throttle valve only has to be saved for one direction of flow. A particularly space-saving and inexpensive construction of the control device results in an embodiment according to claims 14, 15, wherein all the necessary components can be sensibly arranged in a confined space and linked together. According to claims 16 to 18 there are particularly advantageous applications of the control device according to the invention, it being particularly expedient if it is used in an electric stacker to control the load hydraulics.
  • drawing
  • Several embodiments of the invention are shown in the drawing and explained in more detail in the following description. 1 shows a first electrohydraulic control device for load-compensated control of a hydraulic motor in a simplified representation, FIG. 2 shows a longitudinal section through part of the first control device according to FIG. 1 in a more constructive embodiment, FIG. 3 shows a diagram with the flow characteristics of the proportional throttle valve according to FIG 1 in a simplified representation and FIGS. 4, 5 and 6 each show a second, third or fourth electrohydraulic control device in a simplified representation.
  • Description of the embodiments
  • FIG. 1 shows an electrohydraulic control device 10 for load-compensated control of a hydraulic motor 11, which is designed here as a single-acting working cylinder, as is used in hoists for lifting and lowering loads, especially in forklifts. The control device 10 has an inlet line 12 which leads from a constant pump 13 to the hydraulic motor 11. At the same time, the hydraulic motor 11 is connected via a drain line 14 to a tank 15 from which the constant pump 13 draws its pressure medium. The load pressure prevailing in the hydraulic motor 11 is tapped by a first electrohydraulic pressure transducer 16, which gives an electrical output signal proportional to the pressure to control electronics 17.
  • A pressure compensator 18 is connected into the inlet line 12, the inlet connection 19 of which is directly connected to the pump 13. Downstream of the pressure compensator 18, a first check valve 21 is connected into the feed line 12, which prevents a lowering function of the engine 11, e.g. if the volume flow of the pump 13 fails, a pressure-controlled measuring orifice 22 is also connected downstream of the first check valve 21 and can be combined in an expedient manner with the first check valve 21. The flow orifice 22 is designed in such a way that it has a linear flow characteristic, i.e. their flow rate over the pressure drop occurring forms a straight line in the corresponding diagram. The construction of this orifice plate 22 in connection with the first check valve 21 will be discussed in more detail in connection with FIG. 2. The pressure in the inlet line 12 between the pressure compensator 18 and the first check valve 21 is tapped by a second electrohydraulic pressure sensor 23, which also transmits its pressure-dependent electrical signal to the electronics 17.
  • The pressure compensator 18 has a 3-way function and for this purpose has, in addition to a motor connection 24, a continuation connection 25 which is secured by a second check valve 26. The pressure compensator 18 has a control element 27 which can be loaded by the force of a spring 28 and by the pressure in a first control connection 29 in the direction of a basic position 31, in which it blocks the continuation connection 25 and the connection from the inlet connection 19 to the motor connection 24 controls. In the opposite direction, the control member 27 is loaded by the pressure in a second control connection 32 and thus by the pressure in the inlet connection 19, as a result of which it can be deflected into a working position 33 in which the motor connection 24 is blocked and the inlet connection 19 is connected to the further connection 25 Has. Of course the control member 27 can assume intermediate transition positions corresponding to the throttling function of the pressure compensator 18. The second check valve 26 is connected downstream of the flow connection 25; it biases the pressure with the help of its spring to such an extent that the control element 27 of the pressure compensator is always moved fully to the right against the force of the spring 29 and the line to port A is closed. To pilot the pressure compensator 18, a proportional pressure valve 34 is provided, which controls the pressure in the first control connection 29 and is supplied with pressure medium from the supply line 12 via a first throttle point 35. A second throttle point 36 serves to relieve the hydraulic connection 24 when the continuation is loaded. The proportional pressure valve 34 is controlled by the control electronics 17, for which purpose its proportional magnet is connected to an output of the control electronics 17.
  • A proportional throttle valve 37, which is designed as a pilot-operated 2-way valve and is designed to seal off the motor 11 in a seat valve type, is connected into the drain line 14. With the proportional valve 37, the volume flow in the drain line 14 can be controlled in proportion to an electrical input signal, for which purpose its proportional magnet is also connected to the control electronics 17. The proportional valve 37 is a valve as is explained in more detail in the earlier patent applications P 40 32 078.2 and P 40 30 952.5. This proportional throttle valve 37 has a characteristic field in which the individual flow characteristic curves differ from one another as a function of the pressure drop that occurs in each case. Such a characteristic field is shown in a simplified and schematic manner in the diagram according to FIG. 3, with a plurality of flow characteristic curves 38 being plotted for the volume flow Q as a function of the flow signal I for several pressures, so that the control behavior of the proportional throttle valve 37 can be recognized in principle.
  • The control electronics 17 can be designed as a microcomputer known per se, in which the functions of a controller, a computer and a table memory are integrated. The control electronics 17 has a setpoint input 41, at which the various values for a specific function of the motor 11 can be entered. Furthermore, the characteristic field for the pressure-dependent different flow characteristics 38 (in FIG. 3) of the proportional throttle valve 37 is stored in the table memory of the control electronics 17 in a manner known per se. The control electronics 17 also contains suitable means in its controller, with which not only the proportional magnets of the proportional pressure valve 34 and the proportional throttle valve 37 can be controlled, but also via which an electric motor 42 driving the constant pump 13 can be controlled.
  • As FIG. 2 shows in more detail, the pressure compensator 18, the check valve 21 with the pressure-controlled measuring orifice 22, the pilot-controlling proportional pressure valve 34, the proportional throttle valve 37 and the two pressure sensors 16, 23 are combined in an electrohydraulic control module 45. The control module 45 has a cuboid housing 46 on which these components are arranged and interconnected. The housing 46 has a longitudinal bore 49 extending between its two end faces 47, 48, which is offset several times and penetrated by chambers, in which the proportional throttle valve 37, the pressure compensator 18 and the proportional pressure valve 34 are arranged coaxially to one another. The proportional throttle valve, designed as a cartridge valve with a seat construction, is installed in the longitudinal bore 49 from the first end face 47, while the control element 27 of the pressure compensator 18, designed as a hollow slide valve, is installed in the longitudinal bore 49 from the second end face 48. The longitudinal bore 49 is closed in the second end face 48 by the proportional pressure valve 34, which the Pressure compensator 18 piloted. In the longitudinal bore 49 leads in the area between the proportional throttle valve 37 and the pressure compensator 18, a channel 51 which is connected to the inlet connection 19. The inlet connection 19 lies in a narrow longitudinal side 52 of the cuboid housing 46, in which the flow connection 25 is also arranged. A consumer connection 50 which can be connected to the motor connection and a tank connection 54 are formed in a second longitudinal side 53 of the housing 46 opposite the first narrow longitudinal side 52. The consumer connection 50 and the continuation connection 25 lie essentially in a plane running perpendicular to the longitudinal bore 49. In an extension of the consumer connection 50, the check valve 21 and the pressure-controlled measuring orifice 22 are formed in the housing 46 and have a common closing element 55. The housing recess 56 receiving the closing member 55 is then designed in the form of the actual valve seat in such a way that the measuring orifice 22 reaches its linear flow characteristic in a manner known per se. The first pressure sensor 16 tapping the load pressure is installed in the first end face 47 above a proportional magnet 57 of the proportional throttle valve 37. The second pressure transducer 23, which picks up the pressure in the feed line 12 upstream of the measuring orifice 22, is installed in the second end face 48, so that it comes to rest above the proportional pressure valve 34. Both pressure transducers 16, 23 are thus essentially coaxial with one another and in an axis parallel to the longitudinal bore 49. With this configuration of the control module 45, essentially all electrohydraulic components can be arranged in a particularly compact and advantageous manner, with the integration of orifice plate 22 and the first Check valve 21 is extremely advantageous.
  • The mode of operation of the control device 10 is explained as follows, reference being made to FIGS. 1 to 3.
  • If the control device 10 is in a so-called switching position neutral circulation, the magnet of the proportional pressure valve 34 is not energized and the valve itself is opened. The first control connection 29 of the pressure compensator 18 is thus relieved to the tank 15. The pressure generated by the second check valve 26 in the feed line 12 acts via the second control connection 32 on the control element 27 of the pressure compensator 18 and causes just such a large force on the control element 27 that it acts against the force of the spring 28 in its working position 33 to Stop is adjusted. As a result, the connection to the motor connection 24 is blocked and the pressure medium delivered by the constant pump 13 flows from the inlet connection 19 to the outlet connection 25. The outlet connection 25 can be loaded with pressure. A parallel control of additional hydraulic motors can be carried out with the electrohydraulic control device 10. So that the section of the feed line 12 upstream of the orifice 22 is relieved, a connection to the tank 15 is provided via the second throttle point 36. In this neutral circulation position, the magnet 57 of the proportional throttle valve 37 is not energized, so that this seat valve reliably blocks the hydraulic motor 11. Furthermore, in this neutral circulation position, the control electronics 17 can switch on the first pressure sensor 16 and thus use its electrical signals for any additional functions, for example for safety functions or for weighing a load which acts on the motor 11.
  • If the neutral circulating current is also not required, the control electronics 17 can switch off the electric motor 42, a load acting on the motor 11 being held hydraulically by the first check valve 21 and the proportional throttle valve 37 designed as a seat valve second check valve intercepted.
  • For the lifting function of the hydraulic motor 11, the electric motor 42, the two pressure sensors 16, 23 and the proportional pressure valve 34 are switched on or activated. The proportional throttle valve 37 is not energized and therefore shuts off the drain line 14 to the tank 15. At the control electronics 17, a value is specified at the setpoint input 41, the size of which is proportional to the size of the desired volume flow to the motor 11. The control valve 17 excites the proportional pressure valve 34, which now blocks the connection to the tank and one in the first control connection 29 Throttles control pressure, which shifts the control member 27 into an intermediate position in which pressure medium flows to the engine 11 via the feed line 12. This volume flow flows downstream of the pressure compensator 18 through the measuring orifice 22, the pressure upstream from the second pressure sensor 23 and the pressure downstream from the first pressure sensor 16 being measured and passed on to the control electronics 17. In the control electronics 17, the pressure drop effective via the orifice plate 22 is therefore determined, from which an associated volume flow can be determined from the linear flow characteristic of the orifice plate 22. The magnitude of this volume flow is compared with the target value at the input 41 and from the resulting difference value in the control electronics 17 such a current value for actuating the proportional pressure valve 34 is determined that this control deviation becomes zero. The measuring orifice 22 is, as can be seen in more detail from Figure 2, designed in the region of the housing recess 56 by a special profile of the bore so that there is a linear dependence of the volume flow Q on the pressure drop Δp. In contrast to a parabolic flow characteristic of a fixed orifice, this straight-line flow characteristic of the measuring orifice 22 ensures that the volume flow can still be fine-tuned even with a very small value. The volume flow when lifting the hydraulic motor 11 can thus be kept constant regardless of pressure changes at the constant pump 13 or in the continuation connection 25, so that an electronically load-compensated lifting function can be achieved.
  • For the lowering function of the hydraulic motor 11, only the first pressure sensor 16 and the proportional throttle valve 37 are switched on or activated by the control electronics 17. All other components are not controlled, at least as long as no additional hydraulic motors are operated. The control electronics 17 is given a value proportional to the volume flow when lowering at the setpoint input 41. The current signal generated by the control electronics 17 opens the proportional throttle valve 37, so that a volume flow flows out of the motor 11 via the drain line 14 to the tank 15. The respective load pressure of the engine 11 is reported by the first pressure sensor 16 to the control electronics 17. As FIG. 3 shows in more detail, the proportional throttle valve 37 has different flow characteristics depending on the pressure. These flow characteristics 38 of the proportional throttle valve 37 are stored in the table memory of the control electronics 17. In the control electronics 17, its computer takes the associated values of the flow characteristic from the table memory in accordance with the load pressure reported by the pressure sensor 16, determines the deviation of the volume flow from the predetermined setpoint and finally calculates a suitable current value for actuating the proportional throttle valve 37, so that the influence of the load pressure in Motor 11 is compensated. With the seat valve 37, an electronically load-compensated lowering can thus be achieved, with a perfect fine control being possible. In addition, the motor 11 can also be lowered even when the force acting on it from the outside is very low and the pressure drop available for the volume flow control is therefore low. If the control electronics 17 fails, an emergency manual control 58 arranged on the proportional throttle valve 37 can be actuated, so that the piston rod on the motor 11 can still be retracted.
  • FIG. 4 shows a second electrohydraulic control device 60 in a simplified representation, which differs from the first control device 10 according to FIG. 1 as follows, the same reference symbols being used for the same components. In the second control device 60, the parallel actuation of additional hydraulic motors is dispensed with, so that a 3-way pressure compensator according to FIG. 1 is omitted and a simpler construction is possible.
  • In the second control device 60, a preload valve 61 is connected in the inlet line 12 connecting the constant pump 13 to the hydraulic motor 11 upstream of the first check valve 21 and the measuring orifice 22, which secures the pressure medium source 13. Furthermore, the drain line 14 is connected downstream of the proportional throttle valve 37 and a third check valve 62 and downstream of the latter a proportional pressure valve 63. The third check valve 62 secures the proportional throttle valve 37. The proportional pressure valve 63 is designed here as a pilot-operated pressure valve which is normally open, that is, when the proportional magnet is not energized, the drain line 14 opens. A cross connection 64 is created between the inlet line 12 and the outlet line 14, which is designed here as a simple node. This cross-connection 64 connects the section of the feed line 12 between the preload valve 61 and the measuring throttle 22 to the section of the discharge line 14 between the third check valve 62 and the proportional pressure valve 63 , a separate, second pressure sensor can be omitted. The function of the second pressure transducer according to FIG. 1 is taken over by the proportional pressure valve 63 in the second control device 60, from whose control signals the respective pressure in the discharge line 14 upstream of the proportional valve 63 can be determined.
  • The mode of operation of the second control device 60 essentially corresponds to the mode of operation of the first control device 10 according to FIG. 1, so that reference is made above all to the differences: With the second control device 60, the neutral circulation function is omitted, since there is no 3-way pressure compensator is available. In the function of holding the hydraulic motor 11, neither the proportional throttle valve 37 nor the proportional pressure valve 63 is actuated by the control electronics 17. The control electronics 17 has only switched on the first pressure sensor 16 in order to use its signals for additional functions.
  • In the lifting function of the hydraulic motor 11, the electronic load pressure-compensated control is achieved in principle in a manner comparable to that of the first control device 10 according to FIG. 1. The electric motor 42, driven by the control electronics 17, generates a volume flow via the constant pump 13, which flows to the motor 11 via the preload valve 61 and the measuring orifice 22. The effective pressure drop across the orifice 22 is determined by reporting the load pressure in the engine 11 from the first pressure sensor 16 to the control electronics 17, while the pressure upstream of the orifice 22 is determined indirectly from the control signal of the pilot-controlled pressure control valve 63. The control electronics 17 can throttle the discharge via the discharge line 14 to the tank by a correspondingly large current signal with the aid of the proportional pressure valve 63 to such an extent that a suitable pressure value is generated upstream of the measuring orifice 22. The effective pressure drop across the measuring throttle 22 can thus be regulated to a constant value regardless of the load in the motor 11, so that a volume flow proportional to the size of the setpoint signal at the input 41 can be controlled independently of the load pressure to the motor 11.
  • The function of lowering the hydraulic motor 11 in the second control device 60 is achieved in the same way as in the first control device according to FIG. 1, in that an electronic load-compensated lowering is achieved with the help of the proportional throttle valve 37 and the first pressure sensor 16 in cooperation with the electronic control device 17, in which the volume flow flows via the drain line 14 to the tank. Since the proportional pressure valve 63 is designed as a normally open valve, it does not need to be actuated by the control electronics 17 when lowering. The preload valve 61 prevents the volume flow from flowing to the pressure medium source 13 when lowering.
  • With the second control device 60, above all, good, linear fine controllability can be achieved with a relatively simple construction.
  • FIG. 5 shows a third electrohydraulic control device 70, which differs from the second control device 60 according to FIG. 4 as follows, the same reference symbols being used for the same components.
  • In the third control device 70, a proportional throttle valve 71 is used instead of the orifice plate 22 according to FIG. 4, which is designed as a double-tight seat valve and in which the function of the third check valve 62 is thus also integrated. By using such a double-tight proportional throttle valve 71, the drain line 14 branches off from the feed line 12 in the region between the preload valve 61 and the proportional throttle valve 71 and leads to the tank 15 via the normally open proportional pressure valve 63.
  • The mode of operation of the third control device 70 largely corresponds to that of the second control device according to FIG. 4, wherein when the hydraulic motor 11 is functioning, only the signals from the first pressure sensor 16 are used in the control electronics 17, while the proportional throttle valve 71 and the pressure control valve 63 are not activated.
  • When lifting, the control electronics 17, in addition to the first pressure sensor 16, control or switch on the proportional throttle valve 71 and the proportional pressure valve 63. The proportional throttle valve 71 can take over the function of the measuring throttle, via which the effective pressure drop is kept constant with the help of the proportional pressure valve 63, so that a load pressure-compensated lifting is possible.
  • When lowering the hydraulic motor 11, the procedure is the same as for the second control device 60 according to FIG. 4, the flow characteristics stored in the control electronics 17 being used to control the proportional throttle valve 71 depending on the pressure signal from the pressure sensor 16 so that the influence of the respective one Load pressure is compensated. The normally open proportional pressure valve 63 is not activated by the control electronics 17.
  • With the third control device 70, an electronically load-compensated lifting and lowering function can thus be achieved, a double-tight seat valve 71 ensuring a perfect seal of the lifted load on the consumer 11. The third control device 70 advantageously manages with a single throttle valve 71.
  • FIG. 6 shows a fourth electrohydraulic control device 80, which differs from the first control device 10 according to FIG. 1 follows differs, the same reference numerals being used for the same components. The fourth control device 80 manages the two functions of lifting and lowering with a single proportional throttle valve 37, which for this purpose lies in a hydraulic rectifier circuit 81, which consists of hydraulic full bridge 82 and four check valves 83 and a bridge diagonal 84 into which the proportional throttle valve 37 is switched. In the arrangement of the check valves 83 shown, the branches 85, 86 of the full bridge 82 form parts of the inlet line 12. In a corresponding manner, the other branches 87 and 88 form parts of the outlet line 14. With the help of the pressure transducers 16, 23, the one that occurs via the proportional throttle valve 37 Tapped pressure difference, the first pressure sensor 16 in turn determines the load pressure in the engine 11. The second pressure transducer 23 determines the pressure downstream of the proportional throttle valve 37 when lifting as well as when lowering. A proportional pressure valve 89 is connected downstream of a summing point 91 on the inlet side into the discharge line 14. The proportional pressure valve 89 is designed here as a normally closed valve. Furthermore, a continuation connection 92 branches off from the summation point 91.
  • The mode of operation of the fourth control device 80 is comparable to that of the first control device 10 according to FIG. 1, in that an electronic load-compensated control of the hydraulic motor 11 is possible when lifting and lowering, and in addition that additional hydraulic motors can be operated in parallel via the continuation connection 92. While in the first control device 10 according to FIG. 1, the electronic load compensation using the characteristic field of the flow characteristic curves of the proportional throttle valve 37 stored in the control electronics 17 is carried out only for the lowering function, in the fourth control device 80 this type of load compensation is also used for the lifting function .
  • In the case of a pure function of holding the hydraulic motor 11, the control electronics 17 need not control a valve and only receives load-dependent signals from the first pressure sensor 16.
  • In the lifting function, the control electronics 17, in addition to the two pressure transducers 16 and 23, activate the proportional throttle valve 37 located in the diagonal 84 of the bridge and work in the manner described, so that the volume flow flowing from the constant pump 13 to the motor 11 is electronically load compensated. When lifting, the proportional pressure valve 89, which is designed as a normally closed valve, is not actuated by the control electronics 17.
  • When lowering, the proportional pressure valve 89 is actuated or opened in addition to the components activated by the control electronics 17 during lifting, so that pressure medium can be relieved to the tank 15 via the drain line 14. The constant pump 13 can be switched on or off as required.
  • As with the first control device 10 according to FIG. 1, a comparable function of neutral circulation can also be carried out with the fourth control device 80 if, with the constant pump 13 switched on and the normally closed proportional pressure valve 89, the volume flow conveyed is passed into the further connection 92 for actuating further hydraulic motors. The proportional throttle valve 37 is not energized and, together with the check valves 83, hydraulically shuts off the motor 11.
  • Of course, changes are possible to the embodiments shown without departing from the spirit of the invention.

Claims (19)

  1. Electrohydraulic control device for load-compensated control of a hydraulic motor (11) with pilot-controlled and proportionally operating valve means (37, 34; 37, 63; 71, 63; 37, 89) which can be actuated electrically and are connected between a pressure medium source (13) and a motor (11), an electrohydraulic pressure sensor (16) for sensing the load pressure in the motor (11), and with an electronic control unit (17) for forming an actuation signal for the valve, characterized in that the valve means are constructed as a 2-way proportional throttle valve (37; 71) of a seat valve design and a proportional valve (34; 63; 89), in that a characteristic diagram of the proportional throttle valve (37; 71) with its throughflow characteristic curves (38) which can change as a function of pressure is stored in the electronic control unit (17), with the aid of which throughflow characteristic curves (38) the electronic control unit (17) forms, from the desired value signal which is entered at the input (41), an actuation signal, bringing about the load compensation, for the proportional throttle valve (37; 71), and in that the electronic control unit (17) is operatively connected to the proportional pressure valve (34; 63; 89) which limits the pump pressure.
  2. Electrohydraulic control device according to Claim 1, characterized in that the electronic control unit (17) is supplied with a second signal by a pressure-dependent component (23; 63) in order to identify an effective pressure difference.
  3. Electrohydraulic control device according to Claim 1, characterized in that the proportional throttle valve (37) is connected into an outflow line (14) which runs between the motor (11) and tank (15), and in that an inflow line (12), into which a pressure balance (18) which is pilot-controlled by the proportional pressure valve (34) and, downstream thereof, a nonreturn valve (21) which protects the motor (11) and a pressure-controlled measurement orifice (22) are connected, runs between the motor (11) and pressure medium source (13), in that the pressure-dependent component for the second signal is a second pressure sensor (23) which, together with the first pressure sensor (16), identifies the pressure gradient occurring by means of the measurement orifice (22) (Figure 1).
  4. Electrohydraulic control device according to Claim3, characterized in that the measurement orifice (22) has an essentially linearly extending throughflow characteristic curve.
  5. Electrohydraulic control device according to Claim 3 or 4, characterized in that the pressure balance (18) is constructed as a 3-way valve with a run-on port (25) and has a basic setting (31) which is centred by a spring (28) and in which the connections from the inflow port (19) to the run-on port (25) are blocked and are opened to a motor port (24) and can be deflected, by the inflow pressure, counter to the force of the spring (28) and of a control pressure in this control port (29) into an operating position (33) in which this connection to the run-on port (25) is opened and the connection to the motor port (24) is closed.
  6. Electrohydraulic control device according to one of Claims 3 to 5, characterized in that the hydraulic port of the second pressure sensor (23) is connected to the inflow line (12) between the pressure balance (18) and nonreturn valve (21) and is connected to the tank (15) via a throttle valve (36).
  7. Electrohydraulic control device according to Claim 1 or 2, characterized in that the proportional throttle valve (37) is connected into an outflow line (14) which runs between the motor (11) and tank (15), and in that an inflow line (12) runs between the motor (11) and pressure medium source (13), into which inflow line (12) a nonreturn valve (21) which protects the motor (11) and a pressure-controlled measurement orifice (22) are connected, in that a bias valve (61) is connected into the inflow line (12) upstream of the nonreturn valve (21) and a third nonreturn valve (62) which protects the proportional throttle valve (37) and the proportional pressure valve (63) are located in the outflow line (14) downstream of the proportional throttle valve (37), and in that a cross connection (64), which leads into the outflow line (14) in the region between the third nonreturn valve (62) and proportional pressure valve (63) branches off from the inflow line (12) between the bias valve (61) and measurement orifice (22) (Figure 4).
  8. Electrohydraulic control device according to Claim 7, characterized in that the measurement orifice (22) has an essentially linear throughflow characteristic curve.
  9. Electric control device according to Claim 7 or 8, characterized in that the proportional pressure valve (63) is constructed as a pilot-controlled valve and its actuation signal forms the second signal for identifying the effective pressure difference.
  10. Electrohydraulic control device according to Claim 1 or 2, characterized in that the 2-way proportional throttle valve (71) is constructed as a double-sealed seat valve and is connected into the inflow line (12) running between the motor (11) and pressure medium source (13), in which inflow line (12) a bias valve (61) is connected between the proportional throttle valve (71) and pressure medium source (13), in that the outflow line (14) branches off from the inflow line (12) between the proportional throttle valve (71) and bias valve (61) and is led to the tank (15) via the proportional pressure valve (63) and in that the throughflow characteristic curves of the proportional throttle valve (71), in particular for both directions of throughflow are stored in the electronic control unit (17) and are used to form the actuation signals (Figure 5).
  11. Electrohydraulic control device according to Claim 1 or 2, characterized in that a hydraulic rectifier circuit (81) with full bridge (82) and nonreturn valves (83) is connected into the inflow line (12) which leads from the pressure medium source (13) to the motor (11), in the bridge diagonals (84) of which full bridge (82) the 2-way proportional throttle valve (27) is located, and in that the outflow line (14) branches off from the inflow line (12) upstream of the rectifier circuit (81) and is led to the tank (15) via the proportional pressure valve (89) (Figure 6).
  12. Electrohydraulic control device according to Claim 11, characterized in that in addition a run-on line (92) to additional hydraulic motors branches off at the branching point (91) of the outflow line (14).
  13. Electrohydraulic control device according to C1aim 11 or 12, characterized in that in each case one pressure sensor (16, 23) is connected to the two corner points of the bridge diagonals (84).
  14. Electrohydraulic control device according to one or more of Claims 3 to 6, characterized in that the proportional throttle valve (37), the proportional pressure valve (34) with the pressure balance (18) which is pilot-controlled by it, the pressure-controlled measurement orifice (22) and the two pressure sensors (16, 23) are arranged in a common housing (46) in which the proportional throttle valve (37), the proportional pressure valve (34) and the pressure balance (18) are arranged coaxially with respect to one another while the measurement orifice (22) is located in a plane running perpendicular thereto.
  15. Electrohydraulic control device according to Claim 14, characterized in that the housing (46) is of cuboid construction and receives the pressure balance (18) in a longitudinal hole (49) running between two end sides (47, 48) while, on the first end side (47), the proportional throttle valve (37) is installed in the longitudinal hole (49) and the first pressure sensor (16) which taps the load pressure in an actuator port (50) is installed, while the proportional pressure valve (34) and the second pressure sensor (23) are installed on the other end side (48), and in that the inflow port (29) and the run-on port (25) are arranged on one narrow longitudinal side (52) and the actuator port (50) and the tank port (54) are arranged on the other narrow longitudinal side (53) of the housing (46).
  16. Electrohydraulic control device according to one or more of Claims 1 to 15, characterized in that the motor (11) is a single-action lifting cylinder.
  17. Electrohydraulic control device according to C1aim 16, characterized in that the pressure medium source is an electrohydraulic pump (13, 42), in particular a fixed displacement pump (13) which is actuated by the electronic control unit (17).
  18. Electrohydraulic control device according to one of Claims 1 to 17, characterized by its use for a lifting mechanism, in particular in an electric high-lift truck.
  19. Electrohydraulic control device according to one or more of Claims 1 to 9 and 14 to 18, characterized in that the first nonreturn valve (21) and the measurement orifice (22) are of an integrated design and have a common closing element (55).
EP92118374A 1991-12-07 1992-10-28 Electrohydraulic control system Expired - Lifetime EP0546300B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE19914140409 DE4140409A1 (en) 1991-12-07 1991-12-07 Electrohydraulic control device
DE4140409 1991-12-07

Publications (2)

Publication Number Publication Date
EP0546300A1 EP0546300A1 (en) 1993-06-16
EP0546300B1 true EP0546300B1 (en) 1996-04-10

Family

ID=6446529

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92118374A Expired - Lifetime EP0546300B1 (en) 1991-12-07 1992-10-28 Electrohydraulic control system

Country Status (2)

Country Link
EP (1) EP0546300B1 (en)
DE (1) DE4140409A1 (en)

Families Citing this family (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4322355A1 (en) * 1993-07-05 1995-01-12 Rexroth Mannesmann Gmbh SHR/EHR system for lifting mechanisms
DE19514704A1 (en) * 1995-04-21 1996-10-24 Rexroth Mannesmann Gmbh Lowcost regulator for tractor plough hydraulic lifting device
DE19542129A1 (en) * 1995-11-11 1997-05-15 Rexroth Mannesmann Gmbh Hydraulic device to control flow of hydraulic fluid
EP0877863A1 (en) * 1996-01-30 1998-11-18 Mannesmann Rexroth AG Hydraulic device for controlling a hydraulic-fluid flow
DE19610181B4 (en) * 1996-03-15 2007-06-06 Bosch Rexroth Aktiengesellschaft Hydraulic control device for a hydraulic consumer with a pulling load
DE19716442A1 (en) * 1997-04-20 1998-10-22 Eckehart Schulze Hydraulic installation on a forklift vehicle
DE19844795A1 (en) 1998-09-30 2000-04-13 Bosch Gmbh Robert Electro-hydraulic device for speed control of a hydraulic lifting cylinder
DE19923345A1 (en) * 1999-05-21 2000-11-23 Mannesmann Rexroth Ag Electrohydraulic control device for hydraulic lifting cylinder has pressure balancing device coupled to pressure medium recycling line with its valve body acted on by spring with variable equivalent pressure
AT408475B (en) * 1999-09-10 2001-12-27 Hoerbiger Hydraulik Arrangement for hydraulically actuating a movable component on a vehicle
NL1014476C2 (en) * 2000-02-23 2001-08-24 Applied Power Inc Hydraulic control device for a vehicle cover cap assembly.
DE10023583B4 (en) * 2000-05-13 2012-05-24 Robert Bosch Gmbh Electrohydraulic lowering module
DE10127904B9 (en) * 2001-06-08 2013-01-17 Linde Material Handling Gmbh Control valve means
DE20208577U1 (en) 2002-06-03 2003-12-11 Hawe Hydraulik Gmbh & Co. Kg Electro-hydraulic lift control device for industrial trucks
DE10330869A1 (en) * 2003-07-09 2005-02-17 Hydac System Gmbh Hydraulic system
DE10338551B3 (en) 2003-08-19 2005-03-17 Cts Fahrzeug-Dachsysteme Gmbh Hydraulic drive system for roofs of vehicles
DE202004014030U1 (en) 2004-09-08 2006-01-12 Hawe Hydraulik Gmbh & Co. Kg Electrohydraulic control device
DE202004014029U1 (en) 2004-09-08 2006-01-12 Hawe Hydraulik Gmbh & Co. Kg Electrohydraulic control device
DE102006029623A1 (en) * 2006-06-28 2008-01-03 Robert Bosch Gmbh Electrohydraulic system, as well as apparatus and method for actuating such
DE102007038933A1 (en) * 2007-08-17 2009-02-19 Hydac System Gmbh cushioning system
SE533383C2 (en) 2008-05-15 2010-09-07 Parker Hannifin Ab Electro-hydraulic control
DE102010005146A1 (en) * 2010-01-19 2011-07-21 KONECRANES Lifting Systems GmbH, 40789 Mobile transport or handling device for receiving and transporting silicon crystals drawn from silicon smelter, has units for controlling switching states of switchable valve arrangement proportional to force of load-bearing capacity device
JP5600274B2 (en) * 2010-08-18 2014-10-01 川崎重工業株式会社 Electro-hydraulic drive system for work machines
DE102013206319A1 (en) * 2013-04-10 2014-10-16 Deere & Company lifting device
EP2985473B1 (en) * 2014-08-11 2017-10-11 HAWE Hydraulik SE Lifting module
CN105035261A (en) * 2015-06-03 2015-11-11 长江南京航道局 Combined mechanism for measuring depth of longitudinal flow bow ship
DK179285B1 (en) * 2016-04-29 2018-04-03 Ins Europe Method of weight determination of a load carried by a lifter of a lifting device and weighing device
CN106286438A (en) * 2016-09-20 2017-01-04 山西汾西矿业(集团)有限责任公司 Fully-mechanized mining working emulsion pump constant-pressure liquid supply system and control method thereof
DE102017008359A1 (en) * 2017-09-06 2019-03-07 Hydac Fluidtechnik Gmbh Valve
DE102018209856A1 (en) * 2018-06-19 2019-12-19 Zf Friedrichshafen Ag Control of a fluid valve

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3222008A1 (en) * 1982-06-11 1983-12-15 Sperry Vickers Hydrostatic or pneumatic drive and method for its operation
DE3347000C2 (en) * 1983-12-24 1992-06-04 Robert Bosch Gmbh, 7000 Stuttgart, De
JPH0830482B2 (en) * 1986-12-30 1996-03-27 マンネズマン・レツクスロス・ゲー・エム・ベー・ハー Control device for at least two hydraulic loads fed by at least one pump

Also Published As

Publication number Publication date
EP0546300A1 (en) 1993-06-16
DE4140409A1 (en) 1993-06-09

Similar Documents

Publication Publication Date Title
US5211196A (en) Proportional seat-type 4-way valve
US5537819A (en) Hydraulic device for working machine
EP3078571B1 (en) Hydraulic steering system
JP4818915B2 (en) Method and arrangement for controlling at least two hydraulic consumers
US4456434A (en) Power transmission
JP3182398B2 (en) Guide electromagnetic control valve and hydraulic control device using the same
EP1073575B1 (en) Hydraulic steering system for a vehicle, especially for a mobile working machine
EP0468944B1 (en) An arrangement for controlling hydraulic motors
US6978607B2 (en) Hydraulic control system
US4977928A (en) Load sensing hydraulic system
US6715402B2 (en) Hydraulic control circuit for operating a split actuator mechanical mechanism
EP1354141B1 (en) Hydraulic control valve system with pressure compensated flow control
DE102004050294B3 (en) Hydraulic valve arrangement
RU2277646C1 (en) System of hydraulic valves
CA2255991C (en) Hydraulic control valve system with load sensing priority
US4986071A (en) Fast response load sense control system
JP4202044B2 (en) Hydraulic system of work machine
US6216456B1 (en) Load sensing hydraulic control system for variable displacement pump
US7614336B2 (en) Hydraulic system having augmented pressure compensation
EP1664551B1 (en) Control system and method for supplying pressure means to at least two hydraulic consumers
EP0462589A2 (en) Control system for load sensing hydraulic drive circuit
EP0760908B1 (en) Control arrangement for at least two hydraulic consumers
EP1281872B1 (en) Electrohydraulic device for controlling a double acting engine
EP1672225B1 (en) Valve arrangement and method of controlling a double-acting hydraulic consumer
US6871574B2 (en) Hydraulic control valve assembly having dual directional spool valves with pilot operated check valves

Legal Events

Date Code Title Description
AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19931208

17Q First examination report despatched

Effective date: 19950116

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

ET Fr: translation filed
REF Corresponds to:

Ref document number: 59205956

Country of ref document: DE

Date of ref document: 19960515

Format of ref document f/p: P

ITF It: translation for a ep patent filed

Owner name: STUDIO JAUMANN

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19960614

26N No opposition filed
PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: GB

Payment date: 20001017

Year of fee payment: 9

Ref country code: GB

Payment date: 20001017

Year of fee payment: 09

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20011028

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20011028

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: FR

Payment date: 20041019

Year of fee payment: 13

PGFP Annual fee paid to national office [announced from national office to epo]

Ref country code: DE

Payment date: 20041222

Year of fee payment: 13

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20051028

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060503

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20060630

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20060630