WO2005093263A1 - Hydraulic control system - Google Patents
Hydraulic control system Download PDFInfo
- Publication number
- WO2005093263A1 WO2005093263A1 PCT/IB2004/003187 IB2004003187W WO2005093263A1 WO 2005093263 A1 WO2005093263 A1 WO 2005093263A1 IB 2004003187 W IB2004003187 W IB 2004003187W WO 2005093263 A1 WO2005093263 A1 WO 2005093263A1
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- WO
- WIPO (PCT)
- Prior art keywords
- load
- pressure
- sensing
- valve
- compensator
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
- F15B11/168—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load with an isolator valve (duplicating valve), i.e. at least one load sense [LS] pressure is derived from a work port load sense pressure but is not a work port pressure itself
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/2053—Type of pump
- F15B2211/20546—Type of pump variable capacity
- F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/255—Flow control functions
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/305—Directional control characterised by the type of valves
- F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
- F15B2211/3053—In combination with a pressure compensating valve
- F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/31—Directional control characterised by the positions of the valve element
- F15B2211/3105—Neutral or centre positions
- F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/32—Directional control characterised by the type of actuation
- F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/355—Pilot pressure control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/605—Load sensing circuits
- F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/605—Load sensing circuits
- F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
- F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/605—Load sensing circuits
- F15B2211/6058—Load sensing circuits with isolator valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/65—Methods of control of the load sensing pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/65—Methods of control of the load sensing pressure
- F15B2211/653—Methods of control of the load sensing pressure the load sensing pressure being higher than the load pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
- F15B2211/78—Control of multiple output members
- F15B2211/781—Control of multiple output members one or more output members having priority
Definitions
- the invention relates to a hydraulic control system of the type mentioned in the preamble of claim 1.
- Such control systems are advantageously used when hydraulic consumers, for example hydraulic drives for a mobile working device, are to be moved by an oil flow conveyed by a pump by means of a directional valve. It is known that the volume flow of the hydraulic oil is regulated according to the need of the sum of the consumers, which is then determined by the delivery rate of a variable displacement pump. The regulation is made possible by a load-sensing signal, which is obtained on the directional valve or on the directional valves and which is a measure of the load on the hydraulic consumer or hydraulic consumers.
- a hydraulic control system of the type mentioned in the preamble of claim 1 is known from DE-Al-39 14 904.
- a servo valve is present here, the control pressure acting on it being arbitrarily controllable by means of a separately controllable adjusting device.
- the control pressure is derived from the highest load pressure, the load-sensing signal, via an orifice.
- a control logic is shown with which the control signal for the servo valve can be adapted to the operating point of the servo pump and / or to that of the consumer. How this happens is not revealed.
- DE-OS-18 01 137 shows a variable displacement pump that can be controlled by an electronic control unit.
- the control device is controlled by a displacement sensor on each of two control valves and by an adjusting element of a flow limiting valve which is connected upstream of another control valve.
- the travel sensors are, for example, manually operated shift levers.
- the pressures effective on the consumers are therefore not taken into account, so that this solution does not implement the actual load-sensing principle.
- a hydraulic drive system is known from EP-B1-0 053 323, in which it is achieved that changes in the loads on a consumer, which lead to pressure changes in the system, do not have an effect on further consumers connected in parallel to one another to the same pump. This is done, among other things, by adjustable throttling points arranged in each branch to a consumer.
- US-A-5,950,429 describes a solution which includes a priority circuit for different consumers. If the sum of the volume flow for all consumers is greater than the maximum volume flow achievable by the pump, the problem of an undersupply arises, so that the operation of the consumers is restricted.
- the priority circuit described gives priority to at least one of the consumers, so that at least its correct operation is guaranteed. The non-priority consumers could stop there.
- DE-Al-191 19 276 describes a similar solution of this type, namely with a priority circuit for two or more consumers. What is special here is that the pressure signal at the output of an upstream 2-way pressure compensator is sent to the load-sensing control line of the pump via a check valve. This ensures that the consumer assigned to the 2-way pressure compensator does not slow down even if the consumer is undersupplied.
- the invention has for its object to provide a hydraulic control system that can easily change the load-sensing signal without permanent external influence so that the consumer or consumers receive a larger oil flow, which has a faster effect of the consumer or the consumer.
- FIGS. 1 and 2 show a hydraulic diagram with a hydraulic control system according to the invention in two different states
- FIGS. 3 and 4 show a hydraulic diagram with two consumers, again in two different states
- 5 and 6 is a sectional view of a compensator in two different working positions
- reference number 1 shows a consumer which is, for example, a double-acting drive cylinder for opening and closing a flap.
- This consumer 1 is controllable by a directional control valve 2 with a pressure compensator 3, which is shown separately here, but can be integrated in the directional control valve 2.
- a proportional volume flow d & s is known
- Hydraulic oil from a pump line 4 to consumer 1 controllable The load pressure of consumer 1 is applied to a load-sensing line marked LSi.
- the aforementioned pressure compensator 3 is drawn in dashed lines because the circuit according to the invention is functional even without the presence of the pressure compensator 3. The solution according to the invention described below is therefore not tied to the presence of this pressure compensator 3.
- a volume flow control pressure pv acts at the outlet of the pressure compensator 3 and influences the volume flow through the directional control valve 2.
- the proportional volume flow can be generated by a controllable pump 5, which regulates the volume flow, ie the delivery rate of the pump 5, according to the load on the consumer 1.
- the regulation takes place on the basis of a pressure present in a control line 6.
- Delivery rate of the pump 5 a pump pressure pp.
- the hydraulic oil flowing out of the consumer 1 flows back to a tank 8 through a tank line 7, in which a tank pressure pr prevails.
- the load pressure of consumer 1 which is referred to as load-sensing pressure P LSI , is applied to a load-sensing line identified by LSi.
- the illustration in FIG. 1 shows the hydraulic diagram when the consumer 1 is actuated.
- the load-sensing pressure P LSI does not directly control the pump 5, but rather a compensator 10 is connected between the load-sensing line LS] and the control line 6.
- This compensator 10 to which the load of the consumer 1 is communicated via the load-sensing line LSi, generates a corrected load-sensing signal which is routed to the control line 6 via a compensator load-sensing line LS ⁇ .
- means are available to influence the load-sensing signal.
- These means comprise a servo valve, to which a signal derived from the respective highest load pressure, which can be arbitrarily influenced by a separately controllable adjusting device, is supplied, as well as a control logic for adaptation to the operating point of the variable pump and / or to that of the consumer.
- the invention creates a simpler solution which does not need any permanent external influence, that is to say acts automatically.
- the compensator 10 is designed in such a way that it can automatically correct the load-sensing signal of the consumer 1 by increasing it by a fixed amount ⁇ p.
- the compensator 10 generates a corrected load sensing pressure P L S IK , which corresponds to the sum of the load sensing pressure P L S I and the fixed amount ⁇ p.
- This corrected load-sensing pressure P L S IK acts on the pump 5 via the control line 6.
- This correction of the load-sensing pressure P LSI causes the pump 2 to generate a larger flow than is usually regulated on the basis of the load-sensing signal from the consumer. The larger flow rate thus available advantageously increases the working speed.
- the correction of the load-sensing pressure P LSI is also advantageous in such a way that any pressure losses in the lines to the consumer 1 are compensated for. ,
- the compensator 10 consists of a compensation valve 11 and a shut-off valve 12. These two valves 11, 12 are actuated hydraulically.
- the compensation valve 11 is a 3/3 way valve, so it has three connections.
- the load-sensing line LSi is connected to one connection, so that the load-sensing pressure P LSI acts on it.
- a second connection of the compensation valve 11 has a connection to the pump line 4.
- a third connection is connected to the compensator load-sensing line LS i K.
- a control piston which will be shown with reference to FIG. 5, acts on the left side of the compensation valve 11, the load-sensing pressure pLsi, which can move the compensation valve 11 into the left position.
- the force of the spring 13 acts on this side.
- the pressure in a switch-off line 15 acts on the right side of the compensation valve 11 and can shift the compensation valve 11 into the right position.
- the position of the compensation valve 11 now also depends on the position of the shut-off valve 12.
- the compensator load-sensing line LS ⁇ connected to the shutdown line 15, which acts on a second hydraulic drive of the compensation valve 11.
- the compensation valve 11 increases the load-sensing pressure P L S I by the fixed amount ⁇ p.
- the corrected load-sensing pressure P LSIK is thus reported to the pump 5.
- the size of the already mentioned fixed amount ⁇ p, by which the corrected load sensitivity pressure P LSIK is increased compared to the load sensing pressure P L S I , is determined by the setting of the spring 13.
- the spring 13 is advantageous dimensioned such that the fixed amount ⁇ p can be set to a value between approximately 3 and 20 bar.
- the delivery capacity of the controllable pump 5 determines the corrected load-sensing pressure LSIK .
- FIG. 1 shows a counter spring 17 assigned to the shutoff valve 12, the meaning of which will be explained later with reference to FIG. 2.
- FIG. 2 contains the same elements as FIG. 1. In the example shown in FIG. 2, consumer 1 is therefore not in operation. 2 also applies that the pressure compensator 3 is not functionally essential, that is to say that the described solution according to the invention can be used in the same way for circuits with and without a pressure compensator 3.
- the compensator 10 is switched off by the fact that the load-sensing pressure P LSI representing the load on this consumer is rendered meaningless by the shutdown of the consumer 1. This is achieved by the shut-off valve 12. Because the load-sensing, pressure P LSI drops, the slide of the shut-off valve 12 moves under the action of the counter spring 17 already mentioned in FIG. 1 into its second position, which in the Fig. Is shown. Now the pump pressure pp reaches the lower connection of the shut-off valve 12 and thus on the shut-off line 15. This has the effect that the compensation valve 11 now also assumes a different position, which is shown in FIG. 2. The above-described increase in the load-sensing pressure P L S 10 by the fixed amount ⁇ p is eliminated.
- the load-sensing pressure P LSI which is present at the upper left connection of the compensation valve 11, is now directly connected to the compensator load-sensing line LSu ⁇ and thus to the control line 6.
- the pressure level in the load-sensing line LS ⁇ and in the compensator load sensing line LS JK. corresponds to the pressure pj in the tank line 7, as has already been mentioned.
- the delivery rate of the pump 5 is not determined by the consumer 1 in the switching state of FIG. 2.
- the circuit according to the invention is not tied to the presence of the pressure compensator 3.
- the effect of the priority circuit is based on the pressure compensator.
- the control spring of the pressure compensator influences the flow through the directional control valve, but not the flow rate of the pump.
- FIGS. 3 and 4 A control system with two consumers is shown below with reference to FIGS. 3 and 4. Elements already shown in FIGS. 1 and 2 are provided with the reference numbers already mentioned there.
- 20 means a tractor that is, for example, a tractor. It contains a part of the hydraulic control system, including the controllable pump 5.
- Reference numeral 21 denotes a work machine, for example a harvesting machine that is pulled by the tractor 20. Tractor 20 and work machine 21 are symbolically represented by dashed rectangles, the parts of the hydraulic system respectively associated with the tractor 20 and the work machine 21 being drawn within these rectangles. The hydraulic lines between tractor 20 and work machine 21 can be connected by couplings 22.
- a first hydraulic consumer 30 for example a double-acting drive cylinder for a power lift.
- This consumer 30 can be controlled by a first directional valve 31 with a pressure compensator 32, which is shown separately here, but can be integrated in the directional valve 31.
- a proportional volume flow of the hydraulic oil from the pump line 4 to the consumer 30 can be regulated in a known manner.
- the load pressure of the consumer 30 is present on a load-sensing line labeled LS 30 .
- the load-sensing line LS 30 is connected to the tank line 7 via the directional control valve 31, and is therefore almost pressureless. 4 shows how the load-sensing line LS 30 represents the load on the first consumer 30.
- a second hydraulic consumer 40 for example a double-acting drive cylinder for opening and closing a flap, is assigned to the work machine 21.
- This second consumer 40 can be controlled in an analogous manner, namely by a second directional valve 41 with a pressure compensator 42.
- a proportional volume flow of the hydraulic oil from the pump line 4 to the consumer 40 can also be regulated in a known manner by means of a throttle point.
- the load pressure of the second consumer 40 is present on a load-sensing line labeled LS 40 . 3 shows the hydraulic diagram when the second consumer 40 is actuated.
- the load-sensing lines LS 30 and LS 40 would each be connected to an input of a shuttle valve 48.
- the output of the shuttle valve 48 is led to the pump 5 via the control line 6.
- the pressure in the control line 6 would then correspond to the higher of the pressures present in the load sensing lines LS 30 and LS 40 .
- the delivery capacity of the pump 5 is determined directly by the consumer 30 or 40 which has the highest load. According to the invention, there is a departure from this known teaching.
- the load-sensing line LS of one consumer is not connected directly to the shuttle valve 48, but is the compensator 10 interposed. In the present exemplary embodiment, this applies to the second consumer 40.
- This compensator 10 to which the load of the second consumer 40 is communicated via the load-sensing line LS 40 , generates a corrected load-sensing signal, which is directed to the one input of the via a compensator load-sensing line LS 40 Shuttle valve 48 is guided.
- the shutoff valve 12 has. In one position, which is shown in FIG. 3, the compensator load-sensing line LS 40 ⁇ is connected to a shutdown line 15, which acts on a second hydraulic drive of the compensation valve 11. In this position of the shutoff valve 12, the compensation valve 11 increases the load-sensing pressure PLS4 0 by the fixed amount ⁇ p. The corrected load-sensing pressure PLS4 0 is thus reported to the shuttle valve 48.
- the size of the actual height of the already mentioned fixed amount ⁇ p, by which the corrected load-sensing pressure PLS4 ⁇ K is increased compared to the load-sensing pressure PLS4 ⁇ , is also determined here by the setting of the spring 13. It is also advantageous in In this case, the spring 13 is dimensioned such that the fixed amount ⁇ p can be set to a value between approximately 3 and 20 bar.
- the corrected load-sensing pressure PLS4 0 K determines the delivery capacity of the controllable pump 5.
- FIG. 3 shows the counter spring 17 associated with the shutoff valve 12, the meaning of which will be explained later with reference to FIG. 4. This also applies to a relief element 49 which is connected to the load-sensing line LS 0 .
- FIG. 4 contains the same elements as FIG. 3, however, the first consumer 30 is also shown in its operating position in the illustration in FIG. 4. In this operating position, the pump pressure pp reaches the consumer 30 in a known manner via a throttle point, with which the flow of hydraulic oil to the bottom side of the consumer 30 can be regulated by correspondingly controlling the directional control valve 31. At the same time, the pressure on the bottom side of the consumer 30 forms the load -Sensing- pressure P LS30 , which is present in the load-sensing line LS 30 and reaches the shuttle valve 48.
- the second consumer 40 is not in operation, be it that it is not controlled or that the working machine 21 with this consumer 40 is separated at the couplings 22.
- the compensator 10 is switched off because the load-sensing pressure PL S 4 ⁇ , which represents the load on this consumer, is rendered meaningless by the decommissioning of the second consumer 40.
- This is also achieved here by the shut-off valve 12.
- the load-sensing pressure P LS 4 ⁇ drops, the slide of the shut-off valve 12 moves into its second position under the action of the counter spring 17 already mentioned in FIG. 3, which is shown in FIG.
- the pump pressure pp reaches the lower connection of the shut-off valve 12 and thus on the shut-off line 15. This has the effect that the compensation valve 11 now also has a different position, which is shown in FIG. 4.
- the load-sensing pressure P L S 4 ⁇ which is present at one connection of the compensation valve 11, is now directly connected to the compensator load-sensing line LS 40 ⁇ and thus to the input of the shuttle valve 48.
- the pressure level in the load -Sensing line LS 40 and in the compensator load-sensing line LS 40 ⁇ corresponds to the pressure level in the tank line 7, ie the pressure pi. 4, the delivery capacity of the pump 5 is determined solely by the first consumer 30.
- the relief member 49 serves to avoid this. A small amount of oil is discharged to the tank via this relief member 49 when there is pressure in the load-sensing line LS 40 . If the second consumer 40 is in operation, the pressure in the load-sensing line LS 40 is maintained because a correspondingly small amount of oil is supplied by the directional valve 41. If the second consumer 40 is not in operation, no subsequent delivery takes place, so that the pressure in the load-sensing line LS 40 is reduced. The function of the valves 11, 12 is ensured by the relief member 49.
- the relief member 49 can be an aperture.
- the amount of oil discharged to the tank via the relief member 49 depends on the level of the pressure in the LS 40 load sensing line. If the load on the second consumer 40 is high, which results in a high load-sensing pressure PL S4O , then the amount of oil discharged via the relief member 49 is also large. It can therefore be advantageous to use a current regulator as the relief element 49. In this case, the volume flow through the relief member 49 is always constant regardless of the pressure, that is to say the load on the consumer 40.
- FIG. 5 shows that position which, according to FIGS. 1 and 3, represents the state when consumer 1 (FIG. 1) or second consumer 40 (FIG. 3) is activated in work machine 21.
- FIG. 6 shows the position corresponding to FIGS. 2 and 4, in which the consumer 1 or the second consumer 40 is not activated.
- FIGS. 5 and 6 a terminal T is to the left shown above, 'of the tank 8 (Fig. 1) of the hydraulic control system performs so connection to the tank line 7 (Fig. 1). 3 and 4, such tank connections are shown by the respective symbols.
- the connection of the load-sensing line LSj and LS 40 is shown at the top right in FIGS. 5 and 6.
- the connection of the compensator load sensing line LSuc or LS 40 ⁇ is shown at the bottom left, the connection to the pump line 4 on the right.
- a compensator control piston 51 In the lower part of the housing 50 there is a horizontal bore in which a compensator control piston 51 can be moved. Its left end is located in a first control pressure chamber 52 into which the shutdown line 15 already shown in FIGS. 1 to 4 opens. The right end of the compensator control piston 51 is located in a second control pressure chamber 53, which has a connection for connecting the load-sensing line LSi or LS 40 , which was also already evident from FIGS. 1 to 4. In this second control pressure chamber 53, the adjustable spring 13 is arranged, which is supported on the one hand against the right end of the compensator control piston 51 and on the other hand against an adjusting device 54. Key elements of the adjustment device 54 are a Stellsc 'hraube 55 and a lock nut 56.
- the shutoff valve 12 is located above the compensation valve 11.
- a shutoff valve control piston 60 is slidably disposed in a horizontal bore in the housing 50.
- the pressure in the unpressurized tank line and, on the other hand, the counter spring 17 act on the left end of the shut-off valve control piston 60. Both were already recognizable from FIGS. 1 to 4.
- the pressure in the load-sensing line LSj or LS 40 acts on the right end of the shut-off valve control piston 60.
- the relief member 49 shown here as a nozzle, between the connection of the load-sensing line LSi or LS 40 and the connection T of the tank line 7 (FIG. 1).
- This relief element 49 can then be omitted if a circuit according to FIGS. 1 and 2 is present, because with this circuit this relief element 49 is not required.
- shutoff valve control piston 60 is in its left end position.
- the shut-off valve control piston 60 is pressed to the left against the counter spring 17 by the pressure in the load-sensing line LSi or LS 40 .
- shutoff valve control piston 60 With this position of the shutoff valve control piston 60, a connection is made between the compensator load sensing line LS ⁇ or LS 40 ⁇ and the first control pressure chamber 52, namely via a first annular groove 61 in the compensator control piston 51, a bore 62 in the shutoff valve - Control piston 60 and the shutdown line 15.
- the second control pressure chamber 53 is through a bore 63 in the compensator
- Control piston 51 is connected to a first space 64 on the circumference of the compensator control piston 51.
- a control chamber 65 is connected to the connection to the pump line 4 on the circumference of the compensator control piston 51.
- the space 64 or the control chamber 65 with the compensator load-sensing line LSi or LS 40 ⁇ becomes horizontal displacement of the compensator control piston 51 connected. Is in the compensator load-sensing line LS 40 LSi K or ⁇ prevailing pressure, namely the corrected load-sensing pressure PL SI K or P LS 4 ⁇ K.
- the compensator control piston 51 moves to the left and thus connects the control chamber 65 to the compensator load-sensing line LSi or LS 4 o ⁇ . This increases the pressure in the compensator load-sensing line LSu or LS 40 ⁇ and presses the compensator control piston 51 back into the middle position shown in FIG. 5, because the pressure in the control chamber 65 corresponds to the pressure pp in the pump line 7, and this is higher than the corrected load-sensing pressure PLSIK or Is PLS40K.
- the compensator control piston 51 is shifted to the right.
- the space 64 is connected to the compensator load-sensing line LS I K or LS 40 ⁇ , so that the pressure in the compensator load-sensing line LSJ K or LS 40 ⁇ decreases because of the pressure in space 64 corresponds to the load-sensing pressure P LS I or P LS4 ⁇ and this is lower than the corrected load-sensing pressure p L s ⁇ or
- the compensator control piston 51 is in equilibrium when the pressure on the left side is the same as the pressure on the right side plus the pressure difference ⁇ p equivalent to the force of the adjustable spring 13. It is thus achieved according to the invention that the corrected load-sensing pressure PLSI or PLS4 ⁇ K is always higher by the amount ⁇ p than the actual load-sensing pressure S I reported by the consumer 1 or the load pressure reported by the second consumer 40 Sensing pressure PLS40-
- FIG. 6 shows the position corresponding to FIG. 4 of the valves combined in the compensator 10, namely the compensation valve 11 and the shut-off valve 12, in which the consumer 1 or the second consumer 40 is not activated.
- the pressure in the load-sensing line LS 0 corresponds to the pressure px in the tank line 7, that is to say generally zero.
- the shut-off valve control piston 60 is pressed to the right. As a result, the pressure acting on the connection for the pump line 4 becomes effective in a recess 70 on the shutoff valve control piston 60.
- Control pressure chamber 53 is connected to the connection of the load-sensing line LSi or LS 40 , in which, as mentioned, tank pressure prevails when the consumer 1 or 40 is switched off. Under this effect of the two-sided pressures, the compensator control piston 51 is shifted to the right, as shown in FIG. 6.
- the connection of the compensator load-sensing line LS IK or LS 40 ⁇ is connected to the chamber 64 and this through the bore 63 in the compensator control piston 51 with the control pressure chamber 53, in which there is tank pressure. Consequently, there is also tank pressure pj in the compensator load sensing line LS IK or LS 40 ⁇ . In this case, the compensator 10 therefore does not pass on an increased pressure signal to the control line 6 (FIG. 1) or to the shuttle valve 48 (FIG. 3).
- FIGS. 5 and 6 thus realizes what has been shown in FIGS. 1 to 4 in a simple and clear manner.
- a further exemplary embodiment of a compensator 10 is shown as a hydraulic diagram.
- the elements contained in the compensator 10 are namely
- the two upper connections of the compensation valve 11 are connected unchanged compared to FIGS. 1 to 4.
- the lower connection of the compensation valve 11 is not connected to the control line 6 or the shuttle valve 48, but to the one connection of the shut-off valve 12 and also acts on the right side of the Compensation valve 11 back.
- the shut-off valve 12 basically receives the pressure corrected by the compensation valve 11 on its upper connection.
- the other upper connection of the shut-off valve 12 is connected to the tank line 7.
- the shutoff valve 12 is controlled as in the first exemplary embodiment according to FIGS. 1 to 4, namely by the load-sensing pressure p s ⁇ (FIGS. 1 and 2) or p L s 4 o (FIGS. 3 and 4) on the one hand and by the counter spring 17 on the other hand.
- the consumer 1 (FIG. 1) or 40 (FIG. 3) is in operation, so that its load is represented by the pressure in the load-sensing line LSj or LS 40 , which is for reasons the clarity is designated in Fig. 7 with LS 1/40 . 8, consumer 1 or 40 is not activated or not switched on.
- the pressure in the load-sensing line LSi or LS 40 corresponds to the pressure px in the tank line 7 because of the relief member 49.
- the difference is that in the solution according to FIGS. 1 to 4, the position of the compensation valve 11 is influenced by the position of the shut-off valve 12.
- the shut-off valve 12 therefore dominates the compensation valve 11. According to FIGS. 7 and 8, this control is lacking.
- the compensation valve 11 always generates the increase in the pressure in the load-sensing line LSi or LS 40 by the amount ⁇ p, ie not only when the consumer 1 or 40 is in operation and the pressure in the load-sensing -Line LSj or LS 40 represents the load of consumer 1 or 40, but also when consumer 1 or 40 is not in operation, so that the pressure in the load sensing line LSi or LS 40 the Pressure pj in the tank line 7 corresponds.
- the corrected load-sensing pressure PLSIK or P LS40 generated by the compensation valve 11. 7 with PL S I / 40 K in the switching state of FIG. 7 is passed through the position of the shut-off valve 12 to the shuttle valve 48, but not in the switching state of FIG. 8.
- the pressure pT in the tank line 7 is passed to the shuttle valve 48.
- the position of the compensation valve 11 is dependent on the position of the shut-off valve 12.
- the position of the shutoff valve 12 thus determines whether the compensation valve 11 is the Increase of the load-sensing pressure PLSI or PLS4 ⁇ , designated PL S I / 4 ⁇ in FIGS. 7 and 8, by the fixed amount ⁇ p or not.
- the position of the compensation valve 11 is independent of the position of the shut-off valve 12 and the position of the shut-off valve 12 determines whether the corrected load-sensing pressure PL S IK or PL S generated by the compensation valve 11 4 ⁇ K is switched to the shuttle valve 48.
- the compensation valve 11 increases the load-sensing pressure S by a fixed amount ⁇ p when the consumer is in operation, and that the shut-off valve 12 renders this increase in the load-sensing pressure PL S ineffective if the consumer is not is in operation, thus switching off the compensator 10.
- the solutions shown act purely hydraulically, that is, they do without a separately controllable actuating device and without special control logic, the solution according to the invention is also particularly safe because incorrect manipulations are excluded.
- An electrical control logic would also require pressure transducers, which in turn can be faulty.
- the invention is not restricted to the exemplary embodiments shown. It can always be used when a larger oil flow is to be set in at least one consumer in a control system, which results in a faster reaction of the consumer or all consumers and / or compensates for pressure losses in the lines to the consumer.
- FIG 3 and 4 each show a consumer 30 or 40 on the tractor 20 and the work machine 21. If more than two consumers are present, such a compensator 10 can be assigned to one or more other consumers.
- the adjustable spring 13 can be set differently in each of these compensators 10. There are thus various possibilities for adapting the delivery capacity of the pump 5 to the requirements of the different consumers.
- the relief member 49 does not necessarily have to be arranged within the compensator 10, that is to say within the housing 50 according to FIGS. 5 and 6. It can also be arranged outside the compensator 10, for example combined with a clutch 22. In particular if there are more than two consumers, of which at least two are assigned a compensator 10, it can be advantageous to provide a common relief member 49 for all compensators 10, which is then advantageously a current regulator.
- FIGS. 1 to 4 show, as consumers, double-acting drive cylinders which are controlled by a directional valve.
- the invention can also be used with other types of consumers and their control, for example when the consumers are hydraulic motors that are controlled by a current regulator.
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- Fluid-Pressure Circuits (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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DE112004002768T DE112004002768B4 (en) | 2004-03-09 | 2004-09-28 | Hydraulic control system |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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CHCH00388/04 | 2004-03-09 | ||
CH3882004 | 2004-03-09 |
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WO2005093263A1 true WO2005093263A1 (en) | 2005-10-06 |
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PCT/IB2004/003187 WO2005093263A1 (en) | 2004-03-09 | 2004-09-28 | Hydraulic control system |
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DE (1) | DE112004002768B4 (en) |
WO (1) | WO2005093263A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2436856A (en) * | 2006-04-07 | 2007-10-10 | Agco Gmbh | Pressure control for system with primary and secondary consumers |
EP1783378A3 (en) * | 2005-11-08 | 2008-05-28 | AGCO GmbH | Hydraulic load-sensing system for agricultural tractors |
EP1760325A3 (en) * | 2005-08-30 | 2008-05-28 | AGCO GmbH | Hydraulic load sensing system for agricultural tractors |
FR2975142A1 (en) * | 2011-05-11 | 2012-11-16 | Fluid System | Load sensing hydraulic system for e.g. farm tractor, has operating slide whose first end is subjected to pressure at flow restrictor device outlet and pressure of calibration spring, and second end is subjected to pressure at device inlet |
EP2878829A1 (en) * | 2013-10-30 | 2015-06-03 | AGCO International GmbH | Hydraulic pressure supply system |
EP3002462A1 (en) * | 2014-09-30 | 2016-04-06 | CLAAS Tractor S.A.S. | Hydraulic control system |
WO2021086859A1 (en) * | 2019-10-27 | 2021-05-06 | Hydraforce, Inc. | Hydraulic actuator system having dynamic load sense boost valve |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102016107526A1 (en) | 2016-04-22 | 2017-10-26 | Claas Industrietechnik Gmbh | Booster valve for a trained as a closed-center system working hydraulics of a land or building economy usable machine |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1801137A1 (en) | 1968-10-04 | 1970-04-16 | Bosch Gmbh Robert | Hydraulic system with an adjustable pump |
EP0010860A1 (en) | 1978-09-28 | 1980-05-14 | Eaton Corporation | Load sensing control for hydraulic system |
EP0053323A1 (en) * | 1980-11-24 | 1982-06-09 | Linde Aktiengesellschaft | Hydrostatic transmission system with a variable pump and several actuators |
DE3914904A1 (en) | 1989-05-05 | 1990-11-08 | Rexroth Mannesmann Gmbh | CONTROL FOR A LOAD-RELATED ADJUSTING PUMP |
DE19615593A1 (en) | 1996-04-19 | 1997-10-23 | Linde Ag | Control for hydraulic drive |
US5950429A (en) | 1997-12-17 | 1999-09-14 | Husco International, Inc. | Hydraulic control valve system with load sensing priority |
DE10119276A1 (en) | 2001-04-20 | 2002-10-24 | Mannesmann Rexroth Ag | Hydraulic control circuit for primary and secondary hydraulic loads where the primary load is the priority load and the control circuit ensures it has an adequate pressure supply |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT350348B (en) * | 1977-08-17 | 1979-05-25 | Voest Ag | PROCESS AND EQUIPMENT FOR MANUFACTURING ONE-SIDED HOT-GALVANIZED SHEET METAL |
DE19720454B4 (en) * | 1997-05-15 | 2008-10-23 | Linde Material Handling Gmbh | Hydrostatic drive system |
-
2004
- 2004-09-28 DE DE112004002768T patent/DE112004002768B4/en active Active
- 2004-09-28 WO PCT/IB2004/003187 patent/WO2005093263A1/en active Application Filing
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1801137A1 (en) | 1968-10-04 | 1970-04-16 | Bosch Gmbh Robert | Hydraulic system with an adjustable pump |
EP0010860A1 (en) | 1978-09-28 | 1980-05-14 | Eaton Corporation | Load sensing control for hydraulic system |
EP0053323A1 (en) * | 1980-11-24 | 1982-06-09 | Linde Aktiengesellschaft | Hydrostatic transmission system with a variable pump and several actuators |
EP0053323B1 (en) | 1980-11-24 | 1986-04-16 | Linde Aktiengesellschaft | Hydrostatic transmission system with a variable pump and several actuators |
DE3914904A1 (en) | 1989-05-05 | 1990-11-08 | Rexroth Mannesmann Gmbh | CONTROL FOR A LOAD-RELATED ADJUSTING PUMP |
DE19615593A1 (en) | 1996-04-19 | 1997-10-23 | Linde Ag | Control for hydraulic drive |
US5950429A (en) | 1997-12-17 | 1999-09-14 | Husco International, Inc. | Hydraulic control valve system with load sensing priority |
DE10119276A1 (en) | 2001-04-20 | 2002-10-24 | Mannesmann Rexroth Ag | Hydraulic control circuit for primary and secondary hydraulic loads where the primary load is the priority load and the control circuit ensures it has an adequate pressure supply |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1760325A3 (en) * | 2005-08-30 | 2008-05-28 | AGCO GmbH | Hydraulic load sensing system for agricultural tractors |
EP1783378A3 (en) * | 2005-11-08 | 2008-05-28 | AGCO GmbH | Hydraulic load-sensing system for agricultural tractors |
GB2436856A (en) * | 2006-04-07 | 2007-10-10 | Agco Gmbh | Pressure control for system with primary and secondary consumers |
EP1843047A2 (en) * | 2006-04-07 | 2007-10-10 | AGCO GmbH | Hydraulic supply systems |
EP1843047A3 (en) * | 2006-04-07 | 2008-05-21 | AGCO GmbH | Hydraulic supply systems |
FR2975142A1 (en) * | 2011-05-11 | 2012-11-16 | Fluid System | Load sensing hydraulic system for e.g. farm tractor, has operating slide whose first end is subjected to pressure at flow restrictor device outlet and pressure of calibration spring, and second end is subjected to pressure at device inlet |
EP2878829A1 (en) * | 2013-10-30 | 2015-06-03 | AGCO International GmbH | Hydraulic pressure supply system |
EP3002462A1 (en) * | 2014-09-30 | 2016-04-06 | CLAAS Tractor S.A.S. | Hydraulic control system |
WO2021086859A1 (en) * | 2019-10-27 | 2021-05-06 | Hydraforce, Inc. | Hydraulic actuator system having dynamic load sense boost valve |
Also Published As
Publication number | Publication date |
---|---|
DE112004002768A5 (en) | 2007-07-19 |
DE112004002768B4 (en) | 2009-02-12 |
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