DE4140408A1 - Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action - Google Patents

Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action

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Publication number
DE4140408A1
DE4140408A1 DE19914140408 DE4140408A DE4140408A1 DE 4140408 A1 DE4140408 A1 DE 4140408A1 DE 19914140408 DE19914140408 DE 19914140408 DE 4140408 A DE4140408 A DE 4140408A DE 4140408 A1 DE4140408 A1 DE 4140408A1
Authority
DE
Germany
Prior art keywords
control
valve
electro
pressure
hydraulic
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.)
Withdrawn
Application number
DE19914140408
Other languages
German (de)
Inventor
Hartmut Dipl.-Ing. Sandau (Fh)
Uwe Dipl.-Ing. 7141 Schwieberdingen De Altmann
Horst Dr. Dr.-Ing. 7000 Stuttgart De 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
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Priority to DE19914140408 priority Critical patent/DE4140408A1/en
Publication of DE4140408A1 publication Critical patent/DE4140408A1/en
Withdrawn legal-status Critical Current

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Classifications

    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05DSYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D7/00Control of flow
    • G05D7/06Control of flow characterised by the use of electric means
    • G05D7/0617Control of flow characterised by the use of electric means specially adapted for fluid materials
    • G05D7/0629Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
    • G05D7/0635Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66FHOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075Constructional features or details
    • B66F9/20Means for actuating or controlling masts, platforms, or forks
    • B66F9/22Hydraulic devices or systems
    • 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
    • F15B11/00Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/003Systems with load-holding valves
    • 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
    • F15B11/00Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/05Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed specially adapted to maintain constant speed, e.g. pressure-compensated, load-responsive
    • 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

Abstract

An electro-hydraulic control unit (10) provides load compensated control of a double acting hydraulic linear actuator (11). The actuator is supplied from a constant speed pump (13) and the load condition is measured by a pressure sensor (16) coupled to an electronic controller (17). The hydraulic blocking of the actuator is provided by a 2/2 directional valve (18) and the load compensated operation is provided by a proportional 2 way restrictor valve (24). An entered reference flow rate signal (27) results in a command for the valve. USE/ADVANTAGE - Mast hydraulic of electric stacker. Maintains load independent operation of hydraulic engine in both directions including hoisting and lowering by electronic control.

Description

State of the art

The invention is based on an electro-hydraulic control Direction for load-compensated control of a hydraulic motor according to the genus specified in the preamble of claim 1.

Such an electrohydraulic control device is already used load compensated control of a hydraulic motor from the DE-OS 25 23 600 known, in which the pressure difference at the inlet and outlet of the proportional valve measured and the position of the Control spool is set using a control circuit so that the influence of the pressure dependent on changes in load is compensated for. The size of the volume flow is therefore un depends on the applied, changing pressure difference and is proportional to the deflection of the control spool. This will be there achieved by that the pressure difference in the control circuit ra and the setpoint for the slide stroke or volume flow the square root value is divided. This output signal will a known position control loop as a setpoint for the valve lift leads. This control device works with a complex 4-way proportional valve that is suitable for mobile applications  less suitable. In addition, the directional valve requires a slide stroke tapping displacement transducer with position control loop for carrying out the electronic load compensation.

Furthermore, from DE 39 31 962 A1 control electronics for electrically adjustable actuator known in order to achieve a linear control behavior the characteristic field of the actuator is written into a table memory and thus in a Microprocessor from a setpoint a corrected control signal is won for the actuator. Characteristic curves cannot be used with this just linearize, but also change arbitrarily, so that too the flow load function of a valve at different pressures can be taken into account. The construction of special electrohydrau Control devices are not taught here.

Advantages of the invention

The electrohydraulic control device according to the invention to the load compensated control of a hydraulic motor with the ident Drawing features of claim 1 have the advantage over the other that with a relatively simple and inexpensive design with essential existing components can be realized and a electronically load-compensated control of the hydraulic motor in allowed in both directions, i.e. when lifting and lowering. By the formation of the proportional throttle valve as a seat valve the leakage was kept low. In addition, despite the out formation as a seat valve a sensitive control when lowering it are sufficient while lifting the pulse-controlled electric motor Constant pump allows fine control. The control device is building relatively compact and light and is therefore particularly suitable for use in mobile applications, especially in electronics forklift.  

The measures listed in the subclaims provide for partial further developments and improvements in claim 1 given control device possible. One is particularly advantageous Training according to claim 2, whereby the control device in simple and inexpensive rea from existing components lizes; the control device can be relatively simple designed so that they also take on additional functions can. It is also expedient if the control device according to An saying 3 is formed so that it can be used to control additional suitable hydraulic consumers. It is also convenient form the control device according to claim 4, whereby it itself can be trained particularly easily and in a space-saving manner. A special one Inexpensive design results according to claim 5, if for Locking function uses a simple switching valve that is cheap is producible and easy to control. Furthermore, it is advisable in a control device according to claim 6, a second proportion Provide throttle valve so that during the lifting process of hydraulic motor a parallel operation of additional hydraulic Consumer is possible. An off is also extremely advantageous formation of the control device according to claim 8, whereby when lowering energy recovery is possible for the hydraulic motor. It also has this training has the advantage of a low noise level drive unit, because a via the pulse-controlled electric motor Speed adjustment is feasible. Training is also in accordance with the claims 11 and 12 particularly cheap because they with a proportional throttle valve and when lifting the hydro motors allow parallel operation of additional consumers. In addition, a cheap, normal Kon can be used as a pressure medium source use the pump. It is also advantageous to control Train direction according to claim 13, whereby in addition to a Pa Parallel operation when lifting also energy recovery when lowering is made possible.  

Further advantageous configurations result from the others Claims, the description and the drawing.

drawing

Several embodiments of the invention are shown in the drawing and explained in more detail in the following description. There, Figs. 1, a first electro-hydraulic Steuerein direction for load-compensated control of a hydraulic motor in a simplified illustration, Fig. 2 is a diagram showing the flow lines of the proportional throttle valve according to Fig. 1 in a simplified representation, and Fig. 3, 4 and respectively 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 cylinder, as used in hoists for lifting, holding 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 an outlet 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 .

To hydraulically shut off the motor 11 from the pump 13 , a check valve function is connected into the feed line 12 , which is designed here as a simple 2/2-way valve 18 . For safe shut-off of the connection, the switching valve 18 is formed as a seat valve, and also electro-hydraulic vorsteuerbar, for which purpose the solenoid 19 is connected to the control electronics 17 in operative connection. The switching valve 18 is expediently designed such that it uses the pressure medium pending at its inlet connection ver for actuation. In the feed line 12 there is a first check valve 21 downstream of the switching valve 18 , which opens towards the hydraulic motor 11 . The switching valve 18 and check valve 21 are therefore in series in an inlet-side section 22 of the inlet line 12 , to which an outlet-side section 23 of the outlet line 14 runs in parallel.

A proportional throttle valve 24 is connected in this parallel, outlet-side section 23 , to which the first pressure sensor 16 is hydraulically connected. This proportional throttle valve 24 is designed as a pilot-operated 2-way valve and is for tight shut-off of the engine 11 leads in a poppet valve type. With this proportional throttle valve 24 , the volume flow in the discharge line 14 can be controlled proportionally to an electrical input signal, for which purpose its proportional magnet 25 is also connected to the control electronics 17 . The proportional throttle valve 24 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 24 has a characteristic field in which the individual flow characteristic curves differ from one another depending on the pressure gradient occurring in each case. In the diagram according to FIG. 2, such a characteristic field is shown in a simplified and schematic manner, with several flow characteristic lines 26 for the volume flow Q depending on the current signal I being plotted for several pressures, so that the control behavior of the proportional throttle valve 24 can be recognized in principle . The outlet-side section 23 is here downstream of the proportional throttle valve 24 as a discharge line 14 directly to the tank 15 .

The control electronics 17 can be designed as a known microcomputer in which the functions of a controller, a computer and a table memory are integrated. The control electronics 17 has a setpoint input 27 , at which the various values for a specific function of the motor 11 , such as lifting, holding, lowering, etc., can be entered. Furthermore, the characteristic curve field for the pressure-dependent different flow characteristic curves 26 of the proportional throttle valve 24 is stored in a manner known per se in the bell memory of the control electronics 17 . The control electronics 17 also contains suitable means in its controller, by means of which not only the switching magnet 19 and the proportional magnet 25 can be controlled, but also via which a constant current pump 13 driving the electric motor 28 can be controlled.

The electric motor 28 is designed here in a special way as an impulsge controlled electric motor, to which an electronic control device 29 is assigned. This electronic control device 29 consists of an electronic control part 31 and an electronic power part 32 which is switched to the electric motor 28 . The control part 31 is in turn controlled via the control electronics 17 .

The pressure side of the constant pump 13 is hydraulically secured by a pressure relief valve 33 . Furthermore branches off from the inlet line 12 upstream of the switching valve 19, a continuation line 34 , to which additional hydraulic consumers can be connected. A return line 35 is provided for the pressure medium return from these additional consumers.

As further shown in FIG. 1, the essential hydraulic components are combined in a lifting and lowering module 36 , the switching valve 18 , the check valve 21 , the proportional throttle valve 24 , the pressure limiting valve 33 and the first pressure sensor 16 being arranged and hydraulically in a housing 37 are interconnected. In this case, the inlet-side section 22 extends in the housing 37 between an inlet connection P and a motor connection A, while the parallel, outlet-side section 23 extends from the motor connection A to a tank connection T. The flow line 34 is a flow connection H and the return line 35 is assigned a second tank connection T1.

The mode of operation of the control device 10 is explained as follows, reference being made to FIGS. 1 and 2.

Is the control device 10 in a so-called position. New tralumlauf, with additional hydraulic consumers actuated who should, then the switching magnet 19 and the proportional magnet 25 are not energized and the pressure transducer 16 is switched off. The motor 11 is hydraulically securely shut off by the proportional throttle valve 24 designed as a seat valve, and by the first check valve 21 . Via the control electronics 17 , the electronic control device 29 is activated, whereby the pulse-controlled electric motor 28 drives the constant pump 13 . The volume flow from the constant pump 13 reaches the inlet-side section 12 , where it is shut off by the switching valve 18 designed as a seat valve and therefore flows via the flow line 34 to the additional union, not shown hydraulic consumers, which can be operated at will. An oil stream returning from there flows out via the return line 35 to the tank 15 .

If the control device 10 in a so-called function hold be operated, in which the neutral circulation current to the additional consumers is not required, the electric motor 28 is switched off. In position hold the first pressure sensor 16 is switched on by the control electronics 17 so that its pressure-dependent signals can be used for any functions, for example for safety functions or for weighing the load.

If the control device 10 is operated in the lifting function of the motor 11 , the control electronics 17 activates the first pressure sensor 16 and excites the switching magnet 19 , so that the switching valve 18 assumes its open position, in which the inlet-side section 22 is opened. At the same time, the electronic control unit 17 switches on the electric motor 28 via the control unit 29 , where a volume flow is generated by the constant pump 13 , which flows through the opened switching valve 18 and the first check valve 21 to the motor 11 and causes the load to be lifted there. The size of the volume flow to the motor 11 can be varied as desired, in which the speed of the Kon constant pump 13 is varied accordingly via the pulse-controlled electric motor 28 . The respective size of the load on the motor 11 , as is always reported by the pressure sensor 16 to the control electronics 17 , has no influence on the size of the volume flow. Thus, with the control device 10, a load-compensated volume flow control to the motor 11 during lifting can be carried out, and sensitive control of the volume flow is also possible.

For the lowering function of the hydraulic motor 11 , only the pressure transducer 16 and the proportional throttle valve 24 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 27 . The generated by the control electronics 17 he current signal opens the proportional throttle valve 24 , so that a volume flow from the motor 11 flows through 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. 2 shows in more detail, the proportional throttle valve 24 has different flow characteristics 26 depending on the pressure. These flow characteristics 26 of the proportional throttle valve 24 are stored in the table memory of the control electronics 17 . In the control electronics 17, its computer takes the corresponding values of the flow characteristic from the table memory in accordance with the load pressure reported by the pressure transducer 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 24 , so that the Influence of the load pressure in the engine 11 on the size of the volume flow is compensated. With the poppet valve 24 , an electronically load-compensated lowering can thus be sufficient, with 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 fall out, an emergency manual control 38 arranged on the proportional throttle valve 24 can be actuated, so that even then the piston rod on the engine 11 can be retracted.

While no additional consumer can be actuated in the control device 10 in the lifting function, in the lowering function the pressure side of the constant pump 13 is shut off by the switching valve 18 and, if necessary, parallel operation of an additional hydraulic consumer can be controlled.

FIG. 3 shows a second electrohydraulic control device 40 in a simplified representation, which differs from the first control device 10 according to FIG. 1 as follows, the same reference numerals being used for the same components.

In the second control device 40 , a second proportional throttle valve 41 is connected in the inlet-side section 22 of the inlet line 12 instead of a switching valve, which is structurally identical to the first proportional throttle valve 24 and whose proportional magnet 42 can be controlled by the control electronics 17 . Furthermore, in the second control device 40, the outlet line 14 leads differently by its outlet-side section 43 downstream of the first proportional throttle valve 24 at a connection point 44 with the inlet line 12 in the area between the pressure medium source and the second proportional throttle valve 41 . Upstream of this connection point 44 , a second check valve 45 is connected into the outlet-side section 43 , which opens towards the connection point 44 . Furthermore, the pressure in the connection point 44 is detected by a second electrohydraulic pressure sensor 46 , which reports correspondingly proportional signals to the control electronics 17 . Furthermore, the second Steuerein device 40 as a pressure medium source has a reversible constant pump 47 , which operates as a pump in a direction of flow of the volume flow to the motor 11 , while it works as a motor in the opposite direction of flow. Accordingly, the electric motor 48 is formed so that it operates in one direction of rotation during the pumping operation of the constant-displacement pump 47 as a motor during opposite direction of rotation during engine operation of the fixed displacement pump 47 to operate as a generator in the. The electronic control device 29 is accordingly designed to speak.

The mode of operation of the second control device 40 corresponds in essential functional sequences to the mode of operation of the first control device 10 according to FIG. 1, so that the following primarily refers to the differences:

In the second control device 40 in the neutral circulation function, when the constant pump 47 supplies additional consumers with pressure medium, the check valve function in the inlet line 12 is taken over by the second proportional throttle valve 41 , while the same function in the outlet line 14 is performed by the second check valve 45 becomes. The function hold when the constant pump 47 does not deliver a pressure medium flow is the same as in the first control device 10 according to FIG. 1.

In the function of lifting the second control device 40 , the volume flow from the constant pump 47 is controlled by means of the pulse-controlled electric motor 48 in the same way as in the first control device 10 to the motor 11 , the second proportional throttle valve 41 being fully opened and thus functioning as a switching valve can, as long as there is no parallel operation of an additional hydraulic motor. However, if an additional consumer is supplied with pressure medium via the continuation line 43 in parallel with the lifting of the motor 11 , the second proportional throttle valve 41 works as a throttle valve controlling the volume flow. The pressure drop occurring via the throttle valve 41 is detected with the help of the two pressure transducers 16 and 46 and reported to the control electronics 17 . In the control electronics 17 , the flow characteristics of the second proportional throttle valve 41 , which are the same as those of the first proportional throttle valve 24 , are stored so that the control electronics 17 forms a control signal for the second proportional magnet 42 from the setpoint signal at the input 27 , so that the second Throttle valve 41 an electronically load-compensated volume flow control to the motor 11 is possible, even when additional hydraulic motors are operated in parallel.

With the lowering function, an electronically load-compensated lowering is controlled in the second control device 40 in the same way as in the first control device 10 with the aid of the first proportional throttle valve 24 and the first pressure sensor 16 . In contrast to the first control device 10 , however, this volume flow when lowering via the second check valve 45 and the connection point 44 is guided into the feed line 12 and reaches the tank 15 via the constant pump 47 now operating in the opposite direction of delivery. The constant pump 47 itself works as a motor and drives the electric motor 48 , which in turn works as a generator ar. In this way, energy recovery during lowering is possible with the help of the electronic Steuerein device 29 . In addition, in the control device 40, the drive unit 47 , 48 has the advantage of a low noise level, since a speed adjustment is possible via the electric motor 48 .

Fig. 4 shows a third electrohydraulic control device 50 , which differs from the first control device 10 according to FIG. 1 as follows, the same reference signs being used for the same components.

The fourth control device 50 manages the two functions of lifting and lowering with a single proportional throttle valve 24 , which for this purpose lies in a hydraulic rectifier circuit 51 , which consists of a hydraulic full bridge 52 and four check valves 53 and a bridge diagonal 54 , in which the Proportional throttle valve 24 is switched. In the ge arrangement shown the check valves 53 , the branches 55 and 56 of the full bridge 52 form parts of the supply line 12th In a corresponding manner, the other branches 57 and 58 form parts of the drain line 14 . With the help of the pressure transducer 16 , 46 , the pressure difference occurring via the proportional throttle valve 24 is tapped, the first pressure transducer 16 in turn averaging the load pressure in the engine 11 . The second pressure sensor 46 determines the pressure downstream of the proportional throttle valve 24 when lifting and when lowering. A pressure control valve 59 is connected downstream of an inflow-side summing point 61 into the discharge line 14 . The pressure control valve 59 is formed here as a normally closed valve, so that the drain line 14 is blocked in the event of a power failure. A magnet 62 of the pressure control valve 59 is controlled by the control electronics 17 . In the feed line 12 between the summing point 61 and the constant pump 13 there is a third check valve 63 which opens to the summing point 61 and thus thus to the valve means. Furthermore, the continuation line 34 also starts from the summation point 61 .

The operation of the third control device 50 is comparable to that of the second control device 40 according to FIG. 3, as when lifting as when lowering an electronically load-compensated control of the hydraulic motor 11 is possible and that when lifting additionally via the continuation line 34 an additional Hydro motor can be operated in parallel. The rectifier circuit 41 flows through the proportional throttle valve 24 when lifting and lowering in the same direction, so that the electronic load compensation can be carried out easily.

If the third control device 50 is operated in the neutral circulation function, the constant pump 13 conveying pressure medium via the further flow line 34 to parallel consumers, none of the four components 16 , 46 , 24 , 59 is activated or switched on by the control electronics 17 . The check valves 53 in the branches 58 and 57 and the seat valve of the proportional throttle valve 24 ensure a safe shut-off, so that the pump pressure cannot have a disruptive effect on the motor 11 .

In the pure function of holding the hydraulic motor 11 , none of the valves 24 and 59 are actuated by the control electronics 17 ; only the first pressure sensor 16 reports load pressure-dependent signals to the control electronics 17 .

In the lifting function, the control electronics 17 activate the two pressure transducers 16 and 46 as well as the proportional throttle valve 24 lying in the bridge diagonal 54 , while at the same time the constant pump 13 is switched on via the electronic control device 29 and the electric motor 28 and a volume flow via the feed line 12 to the engine 11 promotes. As long as there is no parallel operation, the proportional throttle valve 24 can function as a switching valve and open fully, the size of the volume flow being controlled by the pulse-controlled electric motor 28 and the constant pump 13 , as is the case with the second control device 40 according to FIG. 3 . If, on the other hand, operation is carried out when lifting in parallel, an electronically load-compensated volume flow control to the motor 11 is carried out with the aid of the proportional throttle valve 24 . The normally closed pressure control valve 59 does not need to be activated when lifting.

When lowering, the pressure control valve 59 is opened by the control electronics 17 , and with the help of the proportional throttle valve 24 and the pressure transducers 16 , 46, an electronically load-compensated volume flow control from the engine 11 to the tank 15 is carried out. The Kon constant pump 13 is secured by the third check valve 63 against this sink current.

FIG. 5 shows a fourth control device 70 , which differs from the third control device 50 according to FIG. 4 as follows, the same reference symbols being used for the same components.

In the fourth control device 70 , the reversible constant pump 47 after the second control device 40 in FIG. 3 is used as the pressure medium source, as is the associated electric motor 48 , which at the same time can also work as a generator. The third check valve 63 in the feed line 12 is omitted in the fourth control device 70 . In addition, a normal pressure relief valve 71 is switched in the drain line 14 instead of the controllable pressure control valve 59 .

The operation of the fourth control device 70 with respect to the electronically load-compensated volume flow control when lifting and lowering the motor 11 is largely comparable to that of the third control device 50 according to FIG. 4. However, in the fourth control device 70, by returning the volume flow when lowering via the Reversible constant pump 47 to tank 15 an energy recovery possible, as has already been described in the second Steuerein direction 40 of FIG. 3.

Of course, changes are made to the embodiments shown possible without departing from the spirit of the invention. The Electronic components can be used in both analog technology and also realize in digital technology.

Claims (15)

1.Electro-hydraulic control device for load-compensated control of a hydraulic motor, with between a pressure medium source and the motor connected, electrically controllable, pre-controlled, proportionally working valve means, with an electro-hydraulic pressure sensor for receiving the load pressure in the engine and with control electronics for forming a control signal for the valve means as a function of the signals from the pressure transducer and from a setpoint input, characterized in that the motor ( 11 ) is a single-acting servomotor for lifting and lowering a load, that the valve means ( 18 , 21 , 24 , 41 , 53 ) a 2-way proportional throttle valve ( 24 ) in seat valve design to control the volume flow when lowering the load and a check valve function ( 18 , 41 , 24 , 53 ) switched in the volume flow when lifting the load, that in the control electronics ( 17 ) Characteristic field of the proportional throttle valve ( 24 ) with the This pressure-dependent variable flow characteristic curve ( 26 ) is stored, with the aid of which the control electronics ( 17 ) form a control signal for the proportional throttle valve ( 24 , 41 ) from the input setpoint signal at the input ( 27 ) and that the pressure medium source is a constant pump ( 13 , 47 ), which is driven by an impulsge controlled electric motor ( 28 , 48 ) which is in operative connection with the control electronics ( 17 ).
2. Electro-hydraulic control device according to claim 1, characterized in that the pulse-controlled electric motor ( 28 , 48 ) is associated with an electronic control device ( 29 ) having a control part ( 31 ) and a power part ( 32 ), the control part ( 31 ) with the Control electronics ( 17 ) is in operative connection.
3. Electro-hydraulic control device according to claim 1 or 2, characterized in that a supply line ( 34 ) for supplying additional hydro from an inlet line ( 12 ) in the region between the pressure medium source ( 13 , 47 ) and valve means ( 18 , 24 , 41 ) branches off.
4. Electro-hydraulic control device according to one of claims 1 to 3, characterized in that the volume flows for lifting and lowering an inlet line ( 12 ) or an outlet line ( 14 ) are assigned that both lines ( 12 , 14 ) each have at least one to each other have parallel section ( 22 , 23 , 43 ), wherein in the outlet-side section ( 23 , 43 ) the 2-way proportional throttle valve ( 24 ) is connected, while in the inlet side section ( 22 ) the valve ( 18 , 41 ) for the blocking function and a first check valve ( 21 ) opening towards the motor ( 11 ) are switched.
5. Electro-hydraulic control device according to claim 4, characterized in that the valve for the locking function as a simple switching valve ( 18 ), in particular for two ways and two positions, formed and its magnet ( 19 ) with the control electronics ( 17 ) Ver connection.
6. Electro-hydraulic control device according to claim 4, characterized in that the valve for the locking function is designed as a second 2-way proportional throttle valve ( 41 ) which is substantially identical to the first proportional throttle valve ( 24 ) and that a second pressure sensor ( 46 ) It is provided which taps the pressure between the valve means ( 41 ) and the pressure medium source ( 47 ) and reports corresponding signals to the control electronics ( 17 ).
7. Electro-hydraulic control device according to one of claims 4 to 6, characterized in that the drain-side section ( 23 ) of the drain line ( 14 ) downstream of the first proportional throttle valve ( 24 ) in the tank ( 15 ) and the constant pump ( 13 ) only for a conveying direction from the tank ( 15 ) to the motor ( 11 ) is formed out.
8. Electro-hydraulic control device according to one of claims 4 to 6, characterized in that the outlet-side section ( 43 ) of the drain line ( 14 ) downstream of the first proportional throttle valve ( 24 ) in the inlet line ( 12 ) in the region between the valve means ( 41 ) and pressure medium source (47) is guided, that the Kon fixed displacement pump (47) as a reversible pump for an engine operation in the opposite flow direction is formed and the items zugeord electric motor (48) can work as a generator current in the opposite direction of rotation.
9. Electro-hydraulic control device according to claim 8, characterized in that in the outlet-side section ( 43 ) to the outlet line ( 12 ) opening, second check valve ( 45 ) is switched GE.
10. Electro-hydraulic control device according to one or more of claims 1 to 9, characterized in that the inlet line ( 12 ) upstream of the valve means ( 18 , 41 ) is secured by a pressure limiting valve ( 33 ) to the tank ( 15 ).
11. Electro-hydraulic control device according to one of claims 1 to 3, characterized in that in the from the pressure medium source ( 13 , 47 ) to the engine ( 11 ) leading inlet line ( 12 ) a hy metallic rectifier circuit ( 51 ) with full bridge ( 52 ) and back Impact valves ( 53 ) is connected, in the bridge diagonal ( 54 ) of which the 2-way proportional throttle valve ( 24 ) is located and that of the feed line ( 12 ) in the area between the rectifier circuit ( 51 ) and pressure medium source ( 13 , 47 ) the drain line ( 34 ) branches to the tank ( 15 ), into which a pressure control valve ( 59 , 71 ) is connected and that a second pressure sensor ( 46 ) is provided, so that at each end of the bridge diagonal ( 54 ) a pressure sensor ( 16 , 46 ) is connected whose signals are fed to the control unit ( 17 ).
12. Electro-hydraulic control device according to claim 11, characterized in that the pressure medium source is a constant pump ( 13 ) for a conveying direction, which is secured by a third check valve ( 63 ) in the feed line ( 12 ) and that the pressure control valve ( 59 ) as normal closed, electro-hydraulically adjustable valve is formed, the magnet ( 62 ) with the control electronics ( 17 ) is in operative connection.
13. Electro-hydraulic control device according to claim 11, characterized in that the pressure medium source is a reversible con stant pump ( 47 ) which is suitable for motor operation with opposite flow direction and the electric motor ( 48 ) can work as a generator in the opposite direction of rotation and that the pressure control valve in the drain line ( 14 ) is designed as a pressure limiting valve ( 71 ).
14. Electro-hydraulic control device according to one of claims 1 to 13, characterized in that the hydraulic valve means ( 18 , 21 , 24 , 41 , 45 , 53 ) and the pressure transducers ( 16 , 46 ) used to control the motor ( 11 ) a common housing ( 37 ) is arranged, which has at least one inlet connection (P), a motor connection (A), a tank connection (T) and a continuation connection (N).
15. Electro-hydraulic control device according to one of claims 1 to 14, characterized by its use to control a Hoist, especially in an electric forklift.
DE19914140408 1991-12-07 1991-12-07 Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action Withdrawn DE4140408A1 (en)

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DE19914140408 DE4140408A1 (en) 1991-12-07 1991-12-07 Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action

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DE19914140408 DE4140408A1 (en) 1991-12-07 1991-12-07 Electrohydraulic control of linear hydraulic actuator - has proportional flow control valve responding to pressure feedback to provide load compensating action

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19716442A1 (en) * 1997-04-20 1998-10-22 Eckehart Schulze Hydraulic installation on a forklift vehicle
EP0908413A2 (en) * 1997-10-08 1999-04-14 Still Wagner GmbH & Co. KG Lift truck with a load grasping device and method for descending the load grasping device
DE19749639A1 (en) * 1997-11-10 1999-05-12 Mannesmann Rexroth Ag Hydraulic circuit
EP1369598A1 (en) 2002-06-03 2003-12-10 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic lifting control device for industrial use vehicles
EP1188934A3 (en) * 2000-09-13 2004-01-21 Robert Bosch Gmbh Control device for an hydraulic volume flow
EP1389686A1 (en) * 2002-08-13 2004-02-18 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic brake module
EP1635070A1 (en) 2004-09-08 2006-03-15 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic control device
EP1635072A1 (en) 2004-09-08 2006-03-15 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic control device
DE102007038933A1 (en) * 2007-08-17 2009-02-19 Hydac System Gmbh cushioning system
DE102007048697A1 (en) * 2007-10-11 2009-04-16 Deere & Company, Moline Hydraulic lifting device
DE102009011865A1 (en) * 2009-03-05 2010-09-16 Jungheinrich Aktiengesellschaft Lifting device for high lift industrial truck, has valve arrangement that stops back flow of hydraulic fluid from non-attached lifting cylinder during actuation of mast lifting cylinder
CN103953619A (en) * 2014-04-25 2014-07-30 哈尔滨飞机工业集团有限责任公司 Variable frequency speed control hoisting device for helicopter
DE102014108370A1 (en) * 2014-06-13 2015-12-17 Jungheinrich Aktiengesellschaft Hydraulic lifting device for a battery-operated industrial truck
AT520171A1 (en) * 2017-06-27 2019-01-15 Engel Austria Gmbh Hydraulic system for a molding machine

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19716442A1 (en) * 1997-04-20 1998-10-22 Eckehart Schulze Hydraulic installation on a forklift vehicle
EP0908413A2 (en) * 1997-10-08 1999-04-14 Still Wagner GmbH & Co. KG Lift truck with a load grasping device and method for descending the load grasping device
EP0908413A3 (en) * 1997-10-08 2001-08-08 Still Wagner GmbH & Co. KG Lift truck with a load grasping device and method for descending the load grasping device
DE19749639A1 (en) * 1997-11-10 1999-05-12 Mannesmann Rexroth Ag Hydraulic circuit
EP1188934A3 (en) * 2000-09-13 2004-01-21 Robert Bosch Gmbh Control device for an hydraulic volume flow
EP1369598A1 (en) 2002-06-03 2003-12-10 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic lifting control device for industrial use vehicles
US6837045B2 (en) 2002-06-03 2005-01-04 Hawe Hydraulik Gmbh & Co. Kg Electrohydraulic lifting control device for industrial trucks
EP1389686A1 (en) * 2002-08-13 2004-02-18 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic brake module
EP1635072A1 (en) 2004-09-08 2006-03-15 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic control device
EP1635070A1 (en) 2004-09-08 2006-03-15 HAWE Hydraulik GmbH & Co. KG Electro-hydraulic control device
DE102007038933A1 (en) * 2007-08-17 2009-02-19 Hydac System Gmbh cushioning system
DE102007048697A1 (en) * 2007-10-11 2009-04-16 Deere & Company, Moline Hydraulic lifting device
DE102009011865A1 (en) * 2009-03-05 2010-09-16 Jungheinrich Aktiengesellschaft Lifting device for high lift industrial truck, has valve arrangement that stops back flow of hydraulic fluid from non-attached lifting cylinder during actuation of mast lifting cylinder
CN103953619A (en) * 2014-04-25 2014-07-30 哈尔滨飞机工业集团有限责任公司 Variable frequency speed control hoisting device for helicopter
DE102014108370A1 (en) * 2014-06-13 2015-12-17 Jungheinrich Aktiengesellschaft Hydraulic lifting device for a battery-operated industrial truck
AT520171A1 (en) * 2017-06-27 2019-01-15 Engel Austria Gmbh Hydraulic system for a molding machine
AT520171B1 (en) * 2017-06-27 2019-12-15 Engel Austria Gmbh Hydraulic system for a molding machine

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