EP3957865B1 - Proportional slide valve with a pressure limiting valve and hydraulic system - Google Patents

Proportional slide valve with a pressure limiting valve and hydraulic system Download PDF

Info

Publication number
EP3957865B1
EP3957865B1 EP21180886.0A EP21180886A EP3957865B1 EP 3957865 B1 EP3957865 B1 EP 3957865B1 EP 21180886 A EP21180886 A EP 21180886A EP 3957865 B1 EP3957865 B1 EP 3957865B1
Authority
EP
European Patent Office
Prior art keywords
valve
pressure
load pressure
line
piston
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.)
Active
Application number
EP21180886.0A
Other languages
German (de)
French (fr)
Other versions
EP3957865A3 (en
EP3957865A2 (en
Inventor
Thomas Wechsel
Bernd Faber
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.)
Hawe Hydraulik SE
Original Assignee
Hawe Hydraulik SE
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 Hawe Hydraulik SE filed Critical Hawe Hydraulik SE
Priority to EP23192544.7A priority Critical patent/EP4254126A3/en
Publication of EP3957865A2 publication Critical patent/EP3957865A2/en
Publication of EP3957865A3 publication Critical patent/EP3957865A3/en
Application granted granted Critical
Publication of EP3957865B1 publication Critical patent/EP3957865B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/024—Pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
    • F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
    • F15B13/0433—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being pressure control 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
    • F15B2211/20—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
    • 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
    • F15B2211/32—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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5159—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/52—Pressure control characterised by the type of actuation
    • F15B2211/528—Pressure control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot pressure control
    • F15B2211/5756—Pilot pressure control for opening a valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6052—Load sensing circuits having valve means between output member and the load sensing circuit using check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—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
    • F15B2211/6055—Load sensing circuits having valve means between output member and the load sensing circuit using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/8606—Control during or prevention of abnormal conditions the abnormal condition being a shock

Definitions

  • the present invention relates to a proportional slide valve with a pressure relief valve for load pressure pressure limitation and a hydraulic system with a proportional slide valve according to the invention.
  • pressure relief valves are regularly used to limit the maximum load pressure (also known as LS pressure relief) in the load pressure signal circuit. Limiting the pressure to a maximum load pressure is necessary to protect the steel structure of the work vehicle. For example, the weld seams on a mast of a forest harvester are designed for a service life that depends in particular on the maximum load (i.e. the maximum expected weight of the tree trunk to be lifted) and the speed of movement of the mast with the load raised.
  • a mobile hydraulic system for such use is offered, for example, by HAWE Hydraulik SE under the name PSL, see publication D 7700-2 Prop.
  • directional valve type PSL, PSV (as of August 2011).
  • the proportional slide valve shown there has a slide piston which can be switched from a neutral position into at least a first switching position via a pilot control that generates a pilot control force.
  • the proportional slide valve has a pressure or P connection, a first pressure outlet or A or B connection, a return line and a first load pressure line connected to a load pressure outlet. In the first switching position, the pressure connection is connected to the first pressure outlet and the first load pressure line.
  • a second load pressure line branches off from the first load pressure line, the second load pressure line being connected to the return line and a pressure relief valve being arranged in the second load pressure line.
  • the pressure relief valve limits the maximum load pressure to be reported to the pump or pump regulator to the set value, for example to 300 bar.
  • the object of the present invention is to demonstrate a proportional slide valve for use in the mobile hydraulics of a work vehicle, in which, under certain conditions Under certain circumstances, higher loads can be moved than the loads actually permissible at maximum deflection of the slide piston.
  • the proportional slide valve according to the invention is distinguished from the proportional slide valves known from the prior art in that the pilot control force acts in the opening direction of the pressure relief valve.
  • An additional force component thus acts in the opening direction of the pressure relief valve, which reduces the force necessary to open the pressure relief valve against the actuating device of the pressure relief valve.
  • the actuating device can be, for example, an adjustable spring or a magnet.
  • an additional force component dependent on the deflection of the slide piston is reported to the pressure relief valve in the opening direction. If the maximum load pressure is limited so that the maximum load is reached with a maximum deflection of the slide piston, a load that is slightly above the actual maximum permissible load can be moved with a smaller deflection of the slide piston. Since only a relatively low speed can be driven with a relatively small deflection of the slide piston, there is no fear of any disadvantage to the service life of the steel structure. The overall force acting on the steel structure remains largely constant because although there is a higher load, a maximum speed is not possible at the same time.
  • the pilot control is a hydraulic pilot control and the pilot control force is a pilot control pressure.
  • a signaling line arrangement preferably connects the pilot control with the pressure relief valve, so that the pilot control pressure is reported to the pressure relief valve via the signaling line arrangement. The additional pilot control force acting in the opening direction of the pressure relief valve can therefore be transmitted in a simple manner.
  • the proportional slide valve expediently has a second pressure outlet.
  • the proportional slide valve can preferably be switched from the neutral position into a second switching position via the pilot control, the pressure connection in the second switching position being connected to the second pressure output and the first load pressure line.
  • Two different hydraulic consumers can therefore be controlled via the proportional spool valve, with the limitation of the maximum load pressure, which depends on the deflection of the spool piston, also being active when the second pressure output is activated.
  • a third load pressure line branches off downstream of the slide piston and upstream of the first pressure outlet in the direction of flow to the pressure outlet, the third load pressure line opening into the second load pressure line upstream of the pressure relief valve and a first check valve being arranged in the third load pressure line.
  • the pressure relief valve is also suitable for use as a shock valve.
  • the check valve is arranged so that the pressure in the second load pressure line acts in the closing direction.
  • a spring or pretensioning device or similar can also be provided on the check valve to ensure that the check valve does not open unintentionally, particularly at low volume flows.
  • a second check valve is arranged in the second load pressure line upstream of the junction of the third load pressure line.
  • the second check valve prevents the hydraulic fluid from flowing out to the slide piston when the first check valve is opened.
  • the first check valve can be a spring-loaded check valve. This has the advantage that, on the one hand, the position of the closing element is defined in the unpressurized position. Furthermore, it can also be ensured that the first check valve does not open unintentionally if the pressure in the second load pressure line may not be sufficient.
  • a fourth load pressure line branches off downstream of the slide piston and upstream of the second pressure outlet in the direction of flow to the second pressure outlet, the fourth load pressure line opening into the second load pressure line upstream of the pressure relief valve and a third check valve being arranged in the fourth load pressure line.
  • the pressure relief valve therefore also acts as a shock valve for pressure peaks at the second pressure connection.
  • the third check valve can be a spring-loaded check valve. This has the advantage that, on the one hand, the position of the closing element is defined in the unpressurized position. Furthermore, it can also be ensured that the third check valve does not open unintentionally if the pressure in the second load pressure line may not be sufficient.
  • the pressure relief valve expediently has a valve housing, the actuating device and a valve piston which can be moved axially in a piston chamber of the valve housing.
  • the valve housing has at least one input port and at least one first connection port, the valve piston having a flow path between the Input port and the first connection port blocks or proportionally releases by the valve piston moving against an actuating force generated by the actuating device between a blocking position and an open position in the piston chamber.
  • the valve housing has a second connection port, with a pressure at the second connection port acting against the actuation force of the actuation device on the valve piston in the opening direction of the pressure relief valve.
  • the second connection connection has a bore passing through the valve housing in the axial direction.
  • the bore is therefore designed to be coaxial with the axis of movement of the valve piston. Such a hole is easy to produce.
  • An axially movable movement element is expediently arranged in the bore, the movement element transmitting a force acting in the direction of the open position to the valve piston when pressure is applied to the second connection port.
  • the pilot control force is transmitted hydraulically and is therefore a pilot control pressure.
  • the force is a product of the pilot pressure and the cross-sectional area of the moving element and "helps" open the pressure relief valve.
  • the movement element has a conical surface and the second connection connection has a corresponding contact surface facing the valve piston. It is particularly advantageous if the contact surface is a seat. On the one hand, this prevents the movement element from falling out of the hole or the connection connection during assembly. On the other hand, damping can also be integrated at least in the closing direction of the pressure relief valve, since the hydraulic fluid cannot flow out via the second connection port due to the tight contact of the movement element.
  • a hydraulic circuit diagram of a hydraulic system 100 according to the invention is shown according to a first embodiment.
  • the hydraulic system 100 is a mobile hydraulic system for a work vehicle, for example a forestry harvester, and includes a proportional slide valve 1 with a pressure relief valve 2.
  • the pressure relief valve 2 is shown here as part of a semi-trailer block, although an integral design is also possible.
  • the proportional spool valve 1 also has a hydraulic pilot control 3, via which a spool piston 4 can be switched from a neutral position N into a first switching position S1 and a second switching position S2.
  • the proportional slide valve 1 has a pressure connection 5 for connecting an input block (not shown), a return line 6 and two pressure outputs A, B for connecting hydraulic consumers.
  • the proportional slide valve 1 has a load pressure signal circuit with a load pressure output 7, a first load pressure line 8, a second load pressure line 9 and a load pressure input 10.
  • the load pressure input 10 is connected to the first load pressure line 8 via a shuttle valve 11.
  • a load pressure signal from another proportional slide valve (not shown) can be fed into the load pressure signal circuit via the load pressure input 10.
  • either the load pressure inlet 10 or the first load pressure line 8 is connected to the load pressure outlet 7 via the shuttle valve 11.
  • the load pressure signal present at the load pressure output 7 is reported via the input block to a hydraulic pump (not shown) or to a pump controller.
  • the pressure inlet 5 is connected via an inlet regulator 12 to both the first load pressure line 8 as well as connected to one of the two pressure outputs A, B, namely to a first pressure output A in the first switching position S1 and a second pressure output B in the second switching position S2.
  • a mast of the forest harvester can be controlled via the first pressure output A.
  • the first load pressure line 8 and the second load pressure line 9 are connected to the return line 6, so that they are completely relieved towards a tank.
  • the second load pressure line 9 branches off from the first load pressure line 8 upstream of the shuttle valve 11 and is connected to the return line 6.
  • the pressure relief valve 2 is arranged in the second load pressure line 9. As shown, a nozzle 13 is arranged in the branch of the second load pressure line 9. Furthermore, the pressure in the second load pressure line 9 is reported to the inlet regulator 12.
  • the pilot control 3 is a hydraulic pilot control 3 which generates a pilot control force for deflecting the slide piston 4.
  • the pilot force is therefore a pilot pressure, which is reported to the pressure relief valve 2 via a signaling line arrangement 14.
  • the pilot pressure in the signaling line arrangement 14 acts on the pressure relief valve 2 on the upstream side.
  • the signaling line arrangement 14 includes a first signaling line 14a, a second signaling line 14b and a shuttle valve 14c. Depending on whether the slide piston 4 is deflected from the neutral position N via the pilot control 3 in the direction of the first switching position S1 or in the direction of the second switching position S2, the pilot control pressure is reported to the pressure relief valve 2 via the first signaling line 14a or via the second signaling line 14b.
  • the pilot pressure therefore acts against the closing force of an actuating device 15 of the pressure limiting valve 2 and "helps" in opening the pressure limiting valve 2.
  • the actuating device 15 is a spring, although other actuating devices (such as a magnet) are also conceivable.
  • a pilot control force proportional to the deflection also acts in the opening direction of the pressure relief valve 2. If the slide piston is deflected, a pressure of up to 20 bar can be reported to the pressure relief valve 2 via the signaling line arrangement 14, for example.
  • the pressure relief valve 2 is designed so that it opens at maximum deflection of the slide piston 4 at a maximum load pressure to be defined in the second load pressure line 9 and thus relieves the load pressure signal circuit to the tank via the return line 6. If the maximum load pressure is limited so that at a maximum deflection of the slide piston 4 the maximum load is reached, a load slightly above the actual maximum load can be moved with a smaller deflection of the slide piston 4. Since only a relatively low speed can be driven with a relatively small deflection of the slide piston 4, there is no need to fear any disadvantage for the steel construction of the forestry harvester. It is then possible to move a load that exceeds the actual maximum load at slow speed.
  • a hydraulic circuit diagram of a second embodiment of a hydraulic system 100 according to the invention is shown.
  • the hydraulic system 100' according to the second embodiment differs from the hydraulic system 100 according to the first embodiment in that a third load pressure line 16 branches off in the flow direction to the first pressure output A, downstream of the slide block 4 and upstream of the first pressure output A.
  • the third load pressure line 16 opens into the second load pressure line 9 upstream of the pressure relief valve 2.
  • a first check valve 17 is arranged in the third load pressure line 16.
  • the first check valve 17 is a spring-loaded check valve in this exemplary embodiment.
  • a second check valve 18 is in the second load pressure line 9 upstream of the
  • junction of the third load pressure line 16 is arranged.
  • a fourth load pressure line 19 branches off downstream of the slide piston 4 and upstream of the second pressure outlet B in the direction of flow to the second pressure outlet B.
  • the fourth load pressure line 19 opens into the second load pressure line 9 upstream of the pressure relief valve 2 and downstream of the second check valve 18.
  • a third check valve 20 is arranged in the fourth load pressure line 19, which is a spring-loaded check valve in this exemplary embodiment.
  • the pressure relief valve 2 is also suitable as a shock valve.
  • the first check valve 17 opens when the pressure in the third load pressure line 16 in front of the first check valve 17 is greater than the sum of the pressure in the second load pressure line 9 and the spring preload of the first check valve 17.
  • the pressure relief valve 2 also opens and therefore relieves the second load pressure line 9 and the third load pressure line 16 via the return line 6 to the tank.
  • the second check valve 18 prevents hydraulic fluid from flowing to the slide piston 4. Accordingly, a pressure surge at the second pressure outlet B is relieved towards the tank via the fourth load pressure line 19, the third check valve 20 and the pressure relief valve 2.
  • Fig. 3 a hydraulic circuit diagram of a third embodiment of the hydraulic system 100" according to the invention is shown.
  • the hydraulic system 100" according to the third embodiment differs from that in Fig. 2 shown hydraulic system 100 'in that the third load pressure line and therefore the first check valve are not provided.
  • the pressure relief valve 2 therefore only acts as a shock valve for the pressure output B.
  • the signaling line arrangement 14 in this exemplary embodiment only includes the second signaling line 14b, which reports the pilot control pressure of the pilot control 3 directly to the pressure relief valve 2.
  • a shuttle valve is not provided.
  • the load pressure limited at the pressure relief valve 2 actually acts, with a load above the maximum load pressure being able to be moved in the second switching position S2.
  • Fig. 4 a hydraulic circuit diagram of a fourth embodiment of a hydraulic system 100′′′, which is not part of the invention, is shown.
  • the hydraulic system 100′′′ according to the fourth embodiment differs from the hydraulic system 100′′ according to the second embodiment in that the signaling line arrangement 14 is completely omitted. Therefore, in this fourth embodiment, no load that is above the maximum defined load can be moved, even with a small slide deflection Nevertheless, the pressure relief valve 2' can also work here as a shock valve if a pressure surge occurs at the first pressure outlet A and via the third load pressure line 16 or at the pressure outlet B and via the fourth load pressure line 19.
  • a pressure relief valve 2 as used in a hydraulic system 100, 100', 100" according to the first, second and third embodiments will now be described.
  • the pressure relief valve 2 is shown as shown Figs. 5 and 6 For example, screwed into a block 21 of the proportional slide valve 1, which is only partially shown.
  • the pressure relief valve 2 has a valve housing 22 with an external thread, which can be screwed into a corresponding hole in the block 21.
  • the pressure relief valve 2 has a valve piston 24 which can be moved axially against the force of the actuating device 15 in a piston chamber 23 of the valve housing 22.
  • the valve housing 22 has a plurality of input connections 25 arranged radially on the circumference of the valve housing 22. As shown, the input connections 25 open into a corresponding first chamber 26 formed in the block 21.
  • valve housing 22 has a plurality of first connection connections 28 which are arranged radially on the circumference of the valve housing 22.
  • the first ones flow as shown Connection connections 28 into a second chamber 29 formed in block 21.
  • valve housing 22 has a second connection port 31.
  • the second connection connection 31 opens into a third chamber 36 formed in block 21.
  • the second connection port 31 has a bore 32 which passes axially through the valve housing 22 and is coaxial with the axis of movement of the valve piston 24.
  • An axially movable movement element 33 is arranged in the bore 32.
  • the movement element 33 is a needle with a conical surface 34.
  • the second connection connection 31 has a corresponding contact surface 35 in the form of a seat facing the valve piston 24.
  • the movement element 33 therefore forms a seat valve with its conical surface 34 together with the contact surface 35, see also Fig. 7 .
  • this arrangement has the advantage that the movement element 33 is held securely in the bore 32, for example when assembling the pressure relief valve 2.
  • valve piston 23 is driven by the force generated by the actuating device 15 in the in Fig. 5 locked position shown. In this position, no hydraulic fluid can flow from the input ports 25 to the first connection ports 28. The flow path between the input ports 25 and the first connection ports 28 is blocked.
  • valve piston 24 moves axially in the piston chamber 23 in the direction of the second connection port 31 Fig. 5 locking position shown.
  • the pressure in the piston chamber 23 increases and the movement element 33 is also moved axially until the conical surface 34 rests tightly on the contact surface 35. This reduces the gap leakage between bore 32 and movement element 33. This makes it possible for the movement of the valve piston 24 to be dampened when the pressure relief valve 2 is closed.

Description

Die vorliegende Erfindung betrifft ein Proportional-Schieberventil mit einem Druckbegrenzungsventil zur Lastdruck- Druckbegrenzung sowie ein Hydrauliksystem mit einem erfindungsgemäßen Proportiona l-Schieberventil.The present invention relates to a proportional slide valve with a pressure relief valve for load pressure pressure limitation and a hydraulic system with a proportional slide valve according to the invention.

In der Mobilhydraulik, beispielsweise im Einsatz in einem Arbeitsfahrzeug, wie einem Forst- Harvester, werden regelmäßig Druckbegrenzungsventile zur Begrenzung des maximalen Lastdrucks (auch als LS-Druckbegrenzung bekannt) im Lastdrucksignalkreis verwendet. Die Druckbegrenzung auf einen maximalen Lastdruck ist notwendig, um den Stahlbau des Arbeitsfahrzeugs zu schützen. So sind beispielsweise die Schweißnähte bei einem Mast eines Forst- Harvesters auf eine Lebensdauer ausgelegt, die insbesondere von der maximalen Last (d.h. dem maximal zu erwartendem Gewicht des anzuhebenden Baumstamms) und der Geschwindigkeit der Bewegung des Mastes mit angehobener Last abhängig sind.In mobile hydraulics, for example when used in a work vehicle such as a forestry harvester, pressure relief valves are regularly used to limit the maximum load pressure (also known as LS pressure relief) in the load pressure signal circuit. Limiting the pressure to a maximum load pressure is necessary to protect the steel structure of the work vehicle. For example, the weld seams on a mast of a forest harvester are designed for a service life that depends in particular on the maximum load (i.e. the maximum expected weight of the tree trunk to be lifted) and the speed of movement of the mast with the load raised.

Ein mobilhydraulisches System für einen derartigen Einsatz wird beispielsweise von der HAWE Hydraulik SE unter dem Namen PSL angeboten, vgl. hierzu die Druckschrift D 7700-2 Prop.-Wegeschieber Typ PSL, PSV (Stand: August 2011). Das dort gezeigte Proportional-Schieberventil weist einen Schieberkolben auf, der aus einer Neutralstellung über eine eine Vorsteuerkraft erzeugende Vorsteuerung in wenigstens eine erste Schaltstellung schaltbar ist. Ferner weist das Proportional-Schieberventil einen Druck- bzw. P-Anschluss, einen ersten Druckausgang bzw. A- oder B- Anschluss, eine Rücklaufleitung und eine mit einem Lastdruckausgang verbundene erste Lastdruckleitung auf. Der Druckanschluss ist in der ersten Schaltstellung mit dem ersten Druckausgang und der ersten Lastdruckleitung verbunden. Aus der ersten Lastdruckleitung zweigt eine zweite Lastdruckleitung ab, wobei die zweite Lastdruckleitung mit der Rücklaufleitung verbunden ist und ein Druckbegrenzungsventil in der zweiten Lastdruckleitung angeordnet ist. Das Druckbegrenzungsventil begrenzt den maximalen an die Pumpe- bzw. den Pumpenregler zu meldenden Lastdruck auf den eingestellten Wert, beispielsweise auf 300 bar.A mobile hydraulic system for such use is offered, for example, by HAWE Hydraulik SE under the name PSL, see publication D 7700-2 Prop. directional valve type PSL, PSV (as of August 2011). The proportional slide valve shown there has a slide piston which can be switched from a neutral position into at least a first switching position via a pilot control that generates a pilot control force. Furthermore, the proportional slide valve has a pressure or P connection, a first pressure outlet or A or B connection, a return line and a first load pressure line connected to a load pressure outlet. In the first switching position, the pressure connection is connected to the first pressure outlet and the first load pressure line. A second load pressure line branches off from the first load pressure line, the second load pressure line being connected to the return line and a pressure relief valve being arranged in the second load pressure line. The pressure relief valve limits the maximum load pressure to be reported to the pump or pump regulator to the set value, for example to 300 bar.

Ferner sind auch aus der DE 101 27 904 A1 , der DE 36 05 980 A1 und der EP 3 018 364 A1 derartige mobilhydraulische System bekannt.Furthermore, there are also from the DE 101 27 904 A1 , the DE 36 05 980 A1 and the EP 3 018 364 A1 Such mobile hydraulic systems are known.

Nachteilig an den bekannten Lösungen ist, dass es keine Möglichkeit gibt, die maximale Last unter gewissen Voraussetzungen zu erhöhen, bei denen die höhere maximale Last keine negativen Auswirkungen auf den Stahlbau des Arbeitsfahrzeugs hat.The disadvantage of the known solutions is that there is no possibility of increasing the maximum load under certain conditions in which the higher maximum load does not have any negative effects on the steel structure of the work vehicle.

Vor diesem Hintergrund ist es die Aufgabe der vorliegenden Erfindung, ein Proportional-Schieberventil für den Einsatz in der Mobilhydraulik eines Arbeitsfahrzeugs aufzuzeigen, bei welchem unter gewissen Umständen auch höhere Lasten als die eigentlich bei maximaler Auslenkung des Schieberkolbens zulässigen Lasten bewegt werden können.Against this background, the object of the present invention is to demonstrate a proportional slide valve for use in the mobile hydraulics of a work vehicle, in which, under certain conditions Under certain circumstances, higher loads can be moved than the loads actually permissible at maximum deflection of the slide piston.

Die Lösung der Aufgabe gelingt mit einem Proportional-Schieberventil gemäß Anspruch 1. Vorteilhafte Weiterbildungen sind in den abhängigen Ansprüchen beschrieben.The problem is solved with a proportional slide valve according to claim 1. Advantageous developments are described in the dependent claims.

Das erfindungsgemäße Proportional-Schieberventil zeichnet sich gegenüber den aus dem Stand der Technik bekannten Proportional-Schieberventilen dadurch aus, dass die Vorsteuerkraft in Aufsteuerrichtung des Druckbegrenzungsventils wirkt. Somit wirkt in Aufsteuerrichtung des Druckbegrenzungsventils eine zusätzliche Kraftkomponente, welche die notwendige Kraft zum Öffnen des Druckbegrenzungsventils gegen die Betätigungseinrichtung des Druckbegrenzungsventils reduziert. Die Betätigungseinrichtung kann beispielsweise eine auch einstellbare Feder oder ein Magnet sein.The proportional slide valve according to the invention is distinguished from the proportional slide valves known from the prior art in that the pilot control force acts in the opening direction of the pressure relief valve. An additional force component thus acts in the opening direction of the pressure relief valve, which reduces the force necessary to open the pressure relief valve against the actuating device of the pressure relief valve. The actuating device can be, for example, an adjustable spring or a magnet.

Mit anderen Worten, es wird eine von der Auslenkung des Schieberkolbens abhängige zusätzliche Kraftkomponente an das Druckbegrenzungsventil in Aufsteuerrichtung gemeldet. Wenn der maximale Lastdruck so begrenzt wird, dass bei einer maximalen Auslenkung des Schieberkolbens die maximale Last erreicht wird, kann bei einer geringeren Auslenkung des Schieberkolbens eine etwas über der eigentlichen maximal zulässigen Last liegende Last bewegt werden. Da bei einer verhältnismäßig geringen Auslenkung des Schieberkolbens auch nur eine verhältnismäßig geringe Geschwindigkeit gefahren werden kann, ist kein Nachteil auf die Lebensdauer des Stahlbaus zu befürchten. Die insgesamt auf den Stahlbau wirkende Kraft bleibt weitgehend konstant, da zwar eine höhere Last wirkt, aber gleichzeitig keine Maximalgeschwindigkeit möglich ist.In other words, an additional force component dependent on the deflection of the slide piston is reported to the pressure relief valve in the opening direction. If the maximum load pressure is limited so that the maximum load is reached with a maximum deflection of the slide piston, a load that is slightly above the actual maximum permissible load can be moved with a smaller deflection of the slide piston. Since only a relatively low speed can be driven with a relatively small deflection of the slide piston, there is no fear of any disadvantage to the service life of the steel structure. The overall force acting on the steel structure remains largely constant because although there is a higher load, a maximum speed is not possible at the same time.

Hierbei ist es von Vorteil, wenn die Vorsteuerung eine hydraulische Vorsteuerung ist und die Vorsteuerkraft ein Vorsteuerdruck ist. Vorzugsweise verbindet hierfür eine Meldeleitungsanordnung die Vorsteuerung mit dem Druckbegrenzungsventil, sodass der Vorsteuerdruck über die Meldeleitungsanordnung an das Druckbegrenzungsventil gemeldet wird. Somit kann die zusätzlich in Aufsteuerrichtung des Druckbegrenzungsventils wirkende Vorsteuerkraft in einfacher Art und Weise übertragen werden.It is advantageous here if the pilot control is a hydraulic pilot control and the pilot control force is a pilot control pressure. For this purpose, a signaling line arrangement preferably connects the pilot control with the pressure relief valve, so that the pilot control pressure is reported to the pressure relief valve via the signaling line arrangement. The additional pilot control force acting in the opening direction of the pressure relief valve can therefore be transmitted in a simple manner.

Zweckmäßigerweise weist das Proportional-Schieberventil einen zweiten Druckausgang auf. Das Proportional-Schieberventil ist vorzugsweise über die Vorsteuerung aus der Neutralstellung in eine zweite Schaltstellung schaltbar, wobei der Druckanschluss in der zweiten Schaltstellung mit dem zweiten Druckausgang und der ersten Lastdruckleitung verbunden ist. Mithin können zwei verschiedene hydraulische Verbraucher über das Proportional-Schieberventil angesteuert werden, wobei die von der Auslenkung des Schieberkolbens abhängige Begrenzung des maximalen Lastdrucks auch bei einer Ansteuerung des zweiten Druckausgangs aktiv ist.The proportional slide valve expediently has a second pressure outlet. The proportional slide valve can preferably be switched from the neutral position into a second switching position via the pilot control, the pressure connection in the second switching position being connected to the second pressure output and the first load pressure line. Two different hydraulic consumers can therefore be controlled via the proportional spool valve, with the limitation of the maximum load pressure, which depends on the deflection of the spool piston, also being active when the second pressure output is activated.

Es ist von Vorteil, wenn eine dritte Lastdruckleitung stromabwärts des Schieberkolbens und stromaufwärts des ersten Druckausgangs bei Strömungsrichtung zum Druckausgang abzweigt, wobei die dritte Lastdruckleitung stromaufwärts des Druckbegrenzungsventils in die zweite Lastdruckleitung mündet und ein erstes Rückschlagventil in der dritten Lastdruckleitung angeordnet ist.It is advantageous if a third load pressure line branches off downstream of the slide piston and upstream of the first pressure outlet in the direction of flow to the pressure outlet, the third load pressure line opening into the second load pressure line upstream of the pressure relief valve and a first check valve being arranged in the third load pressure line.

Da über das Druckbegrenzungsventil eine große Menge an Hydraulikflüssigkeit in kurzer Zeit abfließen kann (d.h. hoher Volumenstrom in l/min), eignet sich das Druckbegrenzungsventil auch zum Einsatz als Schockventil. Das Rückschlagventil ist so angeordnet, dass der Druck in der zweiten Lastdruckleitung in Schließrichtung wirkt. Zusätzlich kann auch eine Feder- oder Vorspannvorrichtung oder ähnliches am Rückschlagventil vorgesehen sein, um sicherzustellen, dass insbesondere bei niedrigen Volumenströmen kein ungewolltes Öffnen des Rückschlagventils erfolgt. Sobald eine Druckspitze am ersten Druckanschluss das Rückschlagventil öffnet, kann Hydraulikflüssigkeit über das dann ebenfalls geöffnete Druckbegrenzungsventil und die Rücklaufleitung zum Tank abfließen.Since a large amount of hydraulic fluid can flow out in a short time via the pressure relief valve (i.e. high volume flow in l/min), the pressure relief valve is also suitable for use as a shock valve. The check valve is arranged so that the pressure in the second load pressure line acts in the closing direction. In addition, a spring or pretensioning device or similar can also be provided on the check valve to ensure that the check valve does not open unintentionally, particularly at low volume flows. As soon as a pressure peak at the first pressure connection opens the check valve, hydraulic fluid can flow out to the tank via the pressure relief valve, which is then also opened, and the return line.

Es ist von Vorteil, wenn stromaufwärts der Einmündung der dritten Lastdruckleitung ein zweites Rückschlagventil in der zweiten Lastdruckleitung angeordnet ist. Das zweite Rückschlagventil verhindert beim Öffnen des ersten Rückschlagventils ein Abfließen der Hydraulikflüssigkeit zum Schieberkolben.It is advantageous if a second check valve is arranged in the second load pressure line upstream of the junction of the third load pressure line. The second check valve prevents the hydraulic fluid from flowing out to the slide piston when the first check valve is opened.

Ferner kann das erste Rückschlagventil ein federbelastetes Rückschlagventil sein. Dies hat den Vorteil, dass zum einen die Position des Schließglieds in der drucklosen Stellung definiert ist. Ferner kann so auch sichergestellt werden, dass das erste Rückschlagventil nicht ungewollt öffnet, wenn der Druck in der zweiten Lastdruckleitung eventuell nicht ausreichend ist.Furthermore, the first check valve can be a spring-loaded check valve. This has the advantage that, on the one hand, the position of the closing element is defined in the unpressurized position. Furthermore, it can also be ensured that the first check valve does not open unintentionally if the pressure in the second load pressure line may not be sufficient.

Ferner ist auch denkbar, dass eine vierte Lastdruckleitung stromabwärts des Schieberkolbens und stromaufwärts des zweiten Druckausgangs bei Strömungsrichtung zum zweiten Druckausgang abzweigt, wobei die vierte Lastdruckleitung stromaufwärts des Druckbegrenzungsventils in die zweite Lastdruckleitung mündet und ein drittes Rückschlagventil in der vierten Lastdruckleitung angeordnet ist. Somit wirkt das Druckbegrenzungsventil auch als Schockventil für Druckspitzen am zweiten Druckanschluss.Furthermore, it is also conceivable that a fourth load pressure line branches off downstream of the slide piston and upstream of the second pressure outlet in the direction of flow to the second pressure outlet, the fourth load pressure line opening into the second load pressure line upstream of the pressure relief valve and a third check valve being arranged in the fourth load pressure line. The pressure relief valve therefore also acts as a shock valve for pressure peaks at the second pressure connection.

Ferner kann das dritte Rückschlagventil ein federbelastetes Rückschlagventil sein. Dies hat den Vorteil, dass zum einen die Position des Schließglieds in der drucklosen Stellung definiert ist. Ferner kann so auch sichergestellt werden, dass das dritte Rückschlagventil nicht ungewollt öffnet, wenn der Druck in der zweiten Lastdruckleitung eventuell nicht ausreichend ist.Furthermore, the third check valve can be a spring-loaded check valve. This has the advantage that, on the one hand, the position of the closing element is defined in the unpressurized position. Furthermore, it can also be ensured that the third check valve does not open unintentionally if the pressure in the second load pressure line may not be sufficient.

Zweckmäßigerweise weist das Druckbegrenzungsventil ein Ventilgehäuse, die Betätigungseinrichtung und einen axial in einer Kolbenkammer des Ventilgehäuses verfahrbaren Ventilkolben auf. Das Ventilgehäuse weist wenigstens einen Eingangsanschluss und wenigstens einen ersten Verbindungsanschluss auf, wobei der Ventilkolben einen Strömungsweg zwischen dem Eingangsanschluss und dem ersten Verbindungsanschluss sperrt oder proportional freigibt, indem sich der Ventilkolben gegen eine von der Betätigungseinrichtung erzeugte Betätigungskraft zwischen einer Sperrstellung und einer Offenstellung in der Kolbenkammer bewegt. Das Ventilgehäuse weist einen zweiten Verbindungsanschluss auf, wobei ein Druck am zweiten Verbindungsanschluss entgegen der Betätigungskraft der Betätigungseinrichtung auf den Ventilkolben in Aufsteuerrichtung des Druckbegrenzungsventils wirkt. Somit ergeben sich die vorstehend bereits beschriebenen Vorteile, dass die gemeldete Vorsteuerkraft bzw. der gemeldete Vorsteuerdruck beim Öffnen des Druckbegrenzungsventils "hilft".The pressure relief valve expediently has a valve housing, the actuating device and a valve piston which can be moved axially in a piston chamber of the valve housing. The valve housing has at least one input port and at least one first connection port, the valve piston having a flow path between the Input port and the first connection port blocks or proportionally releases by the valve piston moving against an actuating force generated by the actuating device between a blocking position and an open position in the piston chamber. The valve housing has a second connection port, with a pressure at the second connection port acting against the actuation force of the actuation device on the valve piston in the opening direction of the pressure relief valve. This results in the advantages already described above that the reported pilot control force or the reported pilot control pressure “helps” when opening the pressure relief valve.

Vorzugsweise weist der zweite Verbindungsanschluss eine das Ventilgehäuse in axialer Richtung durchsetzende Bohrung auf. Mithin ist die Bohrung also koaxial mit der Bewegungsachse des Ventilkolbens ausgeführt. Eine solche Bohrung ist leicht herzustellen.Preferably, the second connection connection has a bore passing through the valve housing in the axial direction. The bore is therefore designed to be coaxial with the axis of movement of the valve piston. Such a hole is easy to produce.

Zweckmäßigerweise ist ein axial bewegliches Bewegungselement in der Bohrung angeordnet, wobei das Bewegungselement bei Druckbeaufschlagung des zweiten Verbindungsanschlusses eine in Richtung der Offenstellung wirkende Kraft auf den Ventilkolben überträgt. Dies ist insbesondere dann von Vorteil, wenn die Vorsteuerkraft hydraulisch übertragen wird und somit ein Vorsteuerdruck ist. In diesem Fall ist die Kraft ein Produkt aus Vorsteuerdruck und Querschnittfläche des Bewegungselements und "hilft" beim Öffnen des Druckbegrenzungsventils.An axially movable movement element is expediently arranged in the bore, the movement element transmitting a force acting in the direction of the open position to the valve piston when pressure is applied to the second connection port. This is particularly advantageous if the pilot control force is transmitted hydraulically and is therefore a pilot control pressure. In this case, the force is a product of the pilot pressure and the cross-sectional area of the moving element and "helps" open the pressure relief valve.

Es ist von Vorteil, wenn das Bewegungselement eine Kegelfläche aufweist und der zweite Verbindungsanschluss eine entsprechende, dem Ventilkolben zugewandte Anlagefläche aufweist. Insbesondere ist es von Vorteil, wenn die Anlagefläche eine Sitzfläche ist. Dies verhindert zum einen, dass das Bewegungselement bei der Montage aus der Bohrung bzw. dem Verbindungsanschluss fällt. Zum anderen kann so auch zumindest in Schließrichtung des Druckbegrenzungsventils eine Dämpfung integriert werden, da die Hydraulikflüssigkeit aufgrund der sitzdichten Anlage des Bewegungselements nicht über den zweiten Verbindungsanschluss abfließen kann.It is advantageous if the movement element has a conical surface and the second connection connection has a corresponding contact surface facing the valve piston. It is particularly advantageous if the contact surface is a seat. On the one hand, this prevents the movement element from falling out of the hole or the connection connection during assembly. On the other hand, damping can also be integrated at least in the closing direction of the pressure relief valve, since the hydraulic fluid cannot flow out via the second connection port due to the tight contact of the movement element.

Ferner gelingt die Lösung der Aufgabe mit einem Hydrauliksystem mit einem erfindungsgemäßen Proportional-Schieberventil.Furthermore, the problem is solved with a hydraulic system with a proportional slide valve according to the invention.

Nachfolgend wird die Erfindung anhand von in den Figuren gezeigten Ausführungsbeispielen näher erläutert. Hierbei zeigen schematisch:

Fig. 1
einen Hydraulikschaltplan eines erfindungsgemäßen Hydrauliksystems;
Fig. 2
einen Hydraulikschaltplan einer zweiten Ausführungsform eines erfindungsgemäßen Hydrauliksystems;
Fig. 3
einen Hydraulikschaltplan einer dritten Ausführungsform eines erfindungsgemäßen Hydrauliksystems;
Fig. 4
einen Hydraulikschaltplan einer vierten und nicht zur Erfindung gehörenden Ausführungsform eines Hydrauliksystems;
Fig. 5
einen Schnitt durch ein erfindungsgemäßes Druckbegrenzungsventil in der Sperrstellung;
Fig. 6
das in Fig. 5 gezeigte Druckbegrenzungsventil in der Offenstellung; und
Fig. 7
eine vergrößerte Darstellung eines zweiten Verbindungsanschlusses des in Fig. 6 gezeigten Druckbegrenzungsventils.
The invention is explained in more detail below using exemplary embodiments shown in the figures. Show schematically:
Fig. 1
a hydraulic circuit diagram of a hydraulic system according to the invention;
Fig. 2
a hydraulic circuit diagram of a second embodiment of a hydraulic system according to the invention;
Fig. 3
a hydraulic circuit diagram of a third embodiment of a hydraulic system according to the invention;
Fig. 4
a hydraulic circuit diagram of a fourth embodiment of a hydraulic system that is not part of the invention;
Fig. 5
a section through a pressure relief valve according to the invention in the blocking position;
Fig. 6
this in Fig. 5 pressure relief valve shown in the open position; and
Fig. 7
an enlarged view of a second connection port of the in Fig. 6 pressure relief valve shown.

In Fig. 1 ist ein Hydraulikschaltplan eines erfindungsgemäßen Hydrauliksystems 100 gemäß einer ersten Ausführungsform gezeigt. Das Hydrauliksystem 100 ist ein Mobilhydrauliksystem für ein Arbeitsfahrzeug, beispielsweise für einen Forst-Harvester, und umfasst ein Proportional-Schieberventil 1 mit einem Druckbegrenzungsventil 2. Das Druckbegrenzungsventil 2 ist hier als Teil eines Aufsattelblocks dargestellt, wobei auch eine integrale Ausführung möglich ist. Das Proportional-Schieberventil 1 weist ferner eine hydraulische Vorsteuerung 3 auf, über welche ein Schieberkolben 4 aus einer Neutralstellung N in eine erste Schaltstellung S1 und eine zweite Schaltstellung S2 schaltbar ist. Das Proportional-Schieberventil 1 weist einen Druckanschluss 5 zum Anschluss eines (nicht dargestellten) Eingangsblocks, eine Rücklaufleitung 6 sowie zwei Druckausgänge A, B zum Anschluss von hydraulischen Verbrauchern auf.In Fig. 1 a hydraulic circuit diagram of a hydraulic system 100 according to the invention is shown according to a first embodiment. The hydraulic system 100 is a mobile hydraulic system for a work vehicle, for example a forestry harvester, and includes a proportional slide valve 1 with a pressure relief valve 2. The pressure relief valve 2 is shown here as part of a semi-trailer block, although an integral design is also possible. The proportional spool valve 1 also has a hydraulic pilot control 3, via which a spool piston 4 can be switched from a neutral position N into a first switching position S1 and a second switching position S2. The proportional slide valve 1 has a pressure connection 5 for connecting an input block (not shown), a return line 6 and two pressure outputs A, B for connecting hydraulic consumers.

Des Weiteren weist das Proportional-Schieberventil 1 einen Lastdrucksignalkreis mit einem Lastdruckausgang 7, einer ersten Lastdruckleitung 8, einer zweiten Lastdruckleitung 9 sowie einem Lastdruckeingang 10 auf. Der Lastdruckeingang 10 ist über ein Wechselventil 11 mit der ersten Lastdruckleitung 8 verbunden. Über den Lastdruckeingang 10 kann ein Lastdrucksignal eines weiteren (nicht dargestellten) Proportional-Schieberventils in den Lastdrucksignalkreis eingespeist werden. Je nachdem ob dann am Lastdruckeingang 10 oder in der ersten Lastdruckleitung 8 der höhere Lastdruck anliegt, wird über das Wechselventil 11 entweder der Lastdruckeingang 10 oder die erste Lastdruckleitung 8 mit dem Lastdruckausgang 7 verbunden. Das am Lastdruckausgang 7 anliegende Lastdrucksignal wird über den Eingangsblock an eine (nicht dargestellte) Hydraulikpumpe bzw. an einen Pumpenregler gemeldet.Furthermore, the proportional slide valve 1 has a load pressure signal circuit with a load pressure output 7, a first load pressure line 8, a second load pressure line 9 and a load pressure input 10. The load pressure input 10 is connected to the first load pressure line 8 via a shuttle valve 11. A load pressure signal from another proportional slide valve (not shown) can be fed into the load pressure signal circuit via the load pressure input 10. Depending on whether the higher load pressure is present at the load pressure inlet 10 or in the first load pressure line 8, either the load pressure inlet 10 or the first load pressure line 8 is connected to the load pressure outlet 7 via the shuttle valve 11. The load pressure signal present at the load pressure output 7 is reported via the input block to a hydraulic pump (not shown) or to a pump controller.

Sofern sich der Schieberkolben 4 in der ersten Schaltstellung S1 oder der zweiten Schaltstellung S2 befindet, ist der Druckeingang 5 über einen Zulaufregler 12 sowohl mit der ersten Lastdruckleitung 8 als auch mit einem der beiden Druckausgänge A, B verbunden, nämlich mit einem ersten Druckausgang A in der ersten Schaltstellung S1 und einem zweiten Druckausgang B in der zweiten Schaltstellung S2. Über den ersten Druckausgang A kann beispielsweise ein Mast des Forst-Harvesters angesteuert werden. In der Neutralstellung N des Schieberkolbens 4 sind die erste Lastdruckleitung 8 und die zweite Lastdruckleitung 9 mit der Rücklaufleitung 6 verbunden, sodass diese vollständig zu einem Tank hin entlastet sind.If the slide piston 4 is in the first switching position S1 or the second switching position S2, the pressure inlet 5 is connected via an inlet regulator 12 to both the first load pressure line 8 as well as connected to one of the two pressure outputs A, B, namely to a first pressure output A in the first switching position S1 and a second pressure output B in the second switching position S2. For example, a mast of the forest harvester can be controlled via the first pressure output A. In the neutral position N of the slide piston 4, the first load pressure line 8 and the second load pressure line 9 are connected to the return line 6, so that they are completely relieved towards a tank.

Die zweite Lastdruckleitung 9 zweigt aus der ersten Lastdruckleitung 8 stromaufwärts des Wechselventils 11 ab und ist mit der Rücklaufleitung 6 verbunden. Das Druckbegrenzungsventil 2 ist in der zweiten Lastdruckleitung 9 angeordnet. Wie dargestellt ist eine Düse 13 im Abzweig der zweiten Lastdruckleitung 9 angeordnet. Ferner wird der Druck in der zweiten Lastdruckleitung 9 an den Zulaufregler 12 gemeldet.The second load pressure line 9 branches off from the first load pressure line 8 upstream of the shuttle valve 11 and is connected to the return line 6. The pressure relief valve 2 is arranged in the second load pressure line 9. As shown, a nozzle 13 is arranged in the branch of the second load pressure line 9. Furthermore, the pressure in the second load pressure line 9 is reported to the inlet regulator 12.

Die Vorsteuerung 3 ist in diesem Ausführungsbeispiel eine hydraulische Vorsteuerung 3 die eine Vorsteuerkraft zur Auslenkung des Schieberkolbens 4 erzeugt. Die Vorsteuerkraft ist mithin ein Vorsteuerdruck, der über eine Meldeleitungsanordnung 14 an das Druckbegrenzungsventil 2 gemeldet wird. Wie dargestellt wirkt der Vorsteuerdruck in der Meldeleitungsanordnung 14 aufsteuerseitig auf das Druckbegrenzungsventil 2.In this exemplary embodiment, the pilot control 3 is a hydraulic pilot control 3 which generates a pilot control force for deflecting the slide piston 4. The pilot force is therefore a pilot pressure, which is reported to the pressure relief valve 2 via a signaling line arrangement 14. As shown, the pilot pressure in the signaling line arrangement 14 acts on the pressure relief valve 2 on the upstream side.

Die Meldeleitungsanordnung 14 umfasst eine erste Meldeleitung 14a, eine zweite Meldeleitung 14b sowie ein Wechselventil 14c. Je nachdem ob der Schieberkolben 4 über die Vorsteuerung 3 in Richtung der ersten Schaltstellung S1 oder in Richtung der zweiten Schaltstellung S2 aus der Neutralstellung N ausgelenkt wird, wird der Vorsteuerdruck über die erste Meldeleitung 14a oder über die zweite Meldeleitung 14b an das Druckbegrenzungsventil 2 gemeldet.The signaling line arrangement 14 includes a first signaling line 14a, a second signaling line 14b and a shuttle valve 14c. Depending on whether the slide piston 4 is deflected from the neutral position N via the pilot control 3 in the direction of the first switching position S1 or in the direction of the second switching position S2, the pilot control pressure is reported to the pressure relief valve 2 via the first signaling line 14a or via the second signaling line 14b.

Der Vorsteuerdruck wirkt also entgegen der Schließkraft einer Betätigungseinrichtung 15 des Druckbegrenzungsventils 2 und "hilft" beim Öffnen des Druckbegrenzungsventils 2. In diesem Ausführungsbeispiel ist die Betätigungseinrichtung 15 eine Feder, wobei auch andere Betätigungseinrichtungen (wie beispielsweise ein Magnet) denkbar sind. In Abhängigkeit von der Auslenkung des Schieberkolbens 4 wirkt somit eine zur Auslenkung proportionale Vorsteuerkraft zusätzlich in Aufsteuerrichtung des Druckbegrenzungsventils 2. Bei einer Auslenkung des Schieberkolbens kann über die Meldeleitungsanordnung 14 beispielsweise ein Druck von bis zu 20 bar an das Druckbegrenzungsventil 2 gemeldet werden.The pilot pressure therefore acts against the closing force of an actuating device 15 of the pressure limiting valve 2 and "helps" in opening the pressure limiting valve 2. In this exemplary embodiment, the actuating device 15 is a spring, although other actuating devices (such as a magnet) are also conceivable. Depending on the deflection of the slide piston 4, a pilot control force proportional to the deflection also acts in the opening direction of the pressure relief valve 2. If the slide piston is deflected, a pressure of up to 20 bar can be reported to the pressure relief valve 2 via the signaling line arrangement 14, for example.

Das Druckbegrenzungsventil 2 ist so ausgelegt, dass es bei maximaler Auslenkung des Schieberkolbens 4 bei einem zu definierenden maximalen Lastdruck in der zweiten Lastdruckleitung 9 öffnet und mithin den Lastdrucksignalkreis zum Tank über die Rücklaufleitung 6 entlastet. Wenn der maximale Lastdruck so begrenzt wird, dass bei einer maximalen Auslenkung des Schieberkolbens 4 die maximale Last erreicht wird, kann bei einer geringeren Auslenkung des Schieberkolbens 4 eine etwas über der eigentlichen maximalen Last liegende Last bewegt werden. Da bei einer verhältnismäßig geringen Auslenkung des Schieberkolbens 4 auch nur eine verhältnismäßig geringe Geschwindigkeit gefahren werden kann, ist kein Nachteil für den Stahlbau des Forst-Harvesters zu befürchten. Es ist also dann möglich, eine über der eigentlichen maximalen Last liegende Last bei langsamer Geschwindigkeit zu bewegen.The pressure relief valve 2 is designed so that it opens at maximum deflection of the slide piston 4 at a maximum load pressure to be defined in the second load pressure line 9 and thus relieves the load pressure signal circuit to the tank via the return line 6. If the maximum load pressure is limited so that at a maximum deflection of the slide piston 4 the maximum load is reached, a load slightly above the actual maximum load can be moved with a smaller deflection of the slide piston 4. Since only a relatively low speed can be driven with a relatively small deflection of the slide piston 4, there is no need to fear any disadvantage for the steel construction of the forestry harvester. It is then possible to move a load that exceeds the actual maximum load at slow speed.

In Fig. 2 ist ein Hydraulikschaltplan einer zweiten Ausführungsform eines erfindungsgemäßen Hydrauliksystems 100` gezeigt. Das Hydrauliksystem 100` gemäß der zweiten Ausführungsform unterscheidet sich von dem Hydrauliksystem 100 gemäß der ersten Ausführungsform zum einen darin, dass eine dritte Lastdruckleitung 16 in Strömungsrichtung zum ersten Druckausgang A stromabwärts der Schieberklobens 4 und stromaufwärts des ersten Druckausgangs A abzweigt. Die dritte Lastdruckleitung 16 mündet stromaufwärts des Druckbegrenzungsventils 2 in die zweite Lastdruckleitung 9. Ein erstes Rückschlagventil 17 ist in der dritten Lastdruckleitung 16 angeordnet. Das erste Rückschlagventil 17 ist in diesem Ausführungsbeispiel ein federbelastetes Rückschlagventil. Ferner ist ein zweites Rückschlagventil 18 in der zweiten Lastdruckleitung 9 stromaufwärts derIn Fig. 2 a hydraulic circuit diagram of a second embodiment of a hydraulic system 100 according to the invention is shown. The hydraulic system 100' according to the second embodiment differs from the hydraulic system 100 according to the first embodiment in that a third load pressure line 16 branches off in the flow direction to the first pressure output A, downstream of the slide block 4 and upstream of the first pressure output A. The third load pressure line 16 opens into the second load pressure line 9 upstream of the pressure relief valve 2. A first check valve 17 is arranged in the third load pressure line 16. The first check valve 17 is a spring-loaded check valve in this exemplary embodiment. Furthermore, a second check valve 18 is in the second load pressure line 9 upstream of the

Einmündung der dritten Lastdruckleitung 16 angeordnet.Junction of the third load pressure line 16 is arranged.

Zum anderen zweigt eine vierte Lastdruckleitung 19 stromabwärts des Schieberkolbens 4 und stromaufwärts des zweiten Druckausgangs B bei Strömungsrichtung zum zweiten Druckausgang B ab. Die vierte Lastdruckleitung 19 mündet stromaufwärts des Druckbegrenzungsventils 2 und stromabwärts des zweiten Rückschlagventils 18 in die zweite Lastdruckleitung 9. Ein drittes Rückschlagventil 20 ist in der vierten Lastdruckleitung 19 angeordnet, welches in diesem Ausführungsbeispiel ein federbelastetes Rückschlagventil ist.On the other hand, a fourth load pressure line 19 branches off downstream of the slide piston 4 and upstream of the second pressure outlet B in the direction of flow to the second pressure outlet B. The fourth load pressure line 19 opens into the second load pressure line 9 upstream of the pressure relief valve 2 and downstream of the second check valve 18. A third check valve 20 is arranged in the fourth load pressure line 19, which is a spring-loaded check valve in this exemplary embodiment.

Da über das Druckbegrenzungsventil 2 ein großer Volumenstrom über eine verhältnismäßig kurze Zeit abfließen kann, eignet sich das Druckbegrenzungsventil 2 auch als Schockventil. Sobald ein Druckstoß über den ersten Druckausgang A erfolgt, beispielsweise wenn der Mast des Forst-Harvesters hängen bleibt, öffnet das erste Rückschlagventil 17, wenn der Druck in der dritten Lastdruckleitung 16 vor dem ersten Rückschlagventil 17 größer ist als die Summe aus dem Druck in der zweiten Lastdruckleitung 9 und der Federvorspannung des ersten Rückschlagventils 17. Das Druckbegrenzungsventil 2 öffnet ebenfalls und entlastet mithin die zweite Lastdruckleitung 9 und die dritte Lastdruckleitung 16 über die Rücklaufleitung 6 zum Tank. Das zweite Rückschlagventil 18 verhindert, dass Hydraulikflüssigkeit zum Schieberkolben 4 abfließt. Entsprechend wird ein Druckstoß am zweiten Druckausgang B über die vierte Lastdruckleitung 19, das dritte Rückschlagventil 20 und das Druckbegrenzungsventil 2 zum Tank hin entlastet.Since a large volume flow can flow over a relatively short time via the pressure relief valve 2, the pressure relief valve 2 is also suitable as a shock valve. As soon as a pressure surge occurs via the first pressure outlet A, for example if the mast of the forest harvester gets stuck, the first check valve 17 opens when the pressure in the third load pressure line 16 in front of the first check valve 17 is greater than the sum of the pressure in the second load pressure line 9 and the spring preload of the first check valve 17. The pressure relief valve 2 also opens and therefore relieves the second load pressure line 9 and the third load pressure line 16 via the return line 6 to the tank. The second check valve 18 prevents hydraulic fluid from flowing to the slide piston 4. Accordingly, a pressure surge at the second pressure outlet B is relieved towards the tank via the fourth load pressure line 19, the third check valve 20 and the pressure relief valve 2.

In Fig. 3 ist ein Hydraulikschaltplan einer dritten Ausführungsform des erfindungsgemäßen Hydrauliksystems 100" gezeigt. Das Hydrauliksystem 100" gemäß der dritten Ausführungsform unterscheidet sich von dem in Fig. 2 gezeigten Hydrauliksystem 100' darin, dass die dritte Lastdruckleitung und mithin das erste Rückschlagventil nicht vorgesehen sind. Mithin wirkt das Druckbegrenzungsventil 2 nur für den Druckausgang B als Schockventil.In Fig. 3 a hydraulic circuit diagram of a third embodiment of the hydraulic system 100" according to the invention is shown. The hydraulic system 100" according to the third embodiment differs from that in Fig. 2 shown hydraulic system 100 'in that the third load pressure line and therefore the first check valve are not provided. The pressure relief valve 2 therefore only acts as a shock valve for the pressure output B.

Ferner umfasst die Meldeleitungsanordnung 14 in diesem Ausführungsbeispiel nur die zweite Meldeleitung 14b, welche den Vorsteuerdruck der Vorsteuerung 3 direkt an das Druckbegrenzungsventil 2 meldet. Ein Wechselventil ist nicht vorgesehen. Somit wirkt in der ersten Schaltstellung S1 tatsächlich der am Druckbegrenzungsventil 2 begrenzte Lastdruck, wobei in der zweiten Schaltstellung S2 eine über dem maximalen Lastdruck liegende Last bewegt werden kann.Furthermore, the signaling line arrangement 14 in this exemplary embodiment only includes the second signaling line 14b, which reports the pilot control pressure of the pilot control 3 directly to the pressure relief valve 2. A shuttle valve is not provided. Thus, in the first switching position S1, the load pressure limited at the pressure relief valve 2 actually acts, with a load above the maximum load pressure being able to be moved in the second switching position S2.

In Fig. 4 ist ein Hydraulikschaltplan einer vierten und nicht zur Erfindung gehörenden Ausführungsform eines Hydrauliksystems 100‴ gezeigt. Das Hydrauliksystem 100‴ gemäß der vierten Ausführungsform unterscheidet sich von dem Hydrauliksystem 100" gemäß der zweiten Ausführungsform dahingehend, dass die Meldeleitungsanordnung 14 vollständig entfällt. Mithin kann bei dieser vierten Ausführungsform auch bei geringer Schieberauslenkung keine Last, die über der maximal definierten Last liegt, bewegt werden. Gleichwohl kann das Druckbegrenzungsventil 2' auch hier als Schockventil arbeiten, wenn ein Druckstoß am ersten Druckausgang A und über die dritte Lastdruckleitung 16 erfolgt bzw. am Druckausgang B und über die vierte Lastdruckleitung 19 erfolgt.In Fig. 4 a hydraulic circuit diagram of a fourth embodiment of a hydraulic system 100‴, which is not part of the invention, is shown. The hydraulic system 100‴ according to the fourth embodiment differs from the hydraulic system 100″ according to the second embodiment in that the signaling line arrangement 14 is completely omitted. Therefore, in this fourth embodiment, no load that is above the maximum defined load can be moved, even with a small slide deflection Nevertheless, the pressure relief valve 2' can also work here as a shock valve if a pressure surge occurs at the first pressure outlet A and via the third load pressure line 16 or at the pressure outlet B and via the fourth load pressure line 19.

Nachfolgend wird nunmehr ein Druckbegrenzungsventil 2 beschrieben, wie es bei einem Hydrauliksystem 100, 100', 100" gemäß der ersten, zweiten und dritten Ausführungsform verwendet wird.A pressure relief valve 2 as used in a hydraulic system 100, 100', 100" according to the first, second and third embodiments will now be described.

Das Druckbegrenzungsventil 2 ist in der Darstellung gemäß Figs. 5 und 6 beispielhaft in einen nur teilweise dargestellten Block 21 des Proportional-Schieberventils 1 eingeschraubt. Hierfür weist das Druckbegrenzungsventil 2 ein Ventilgehäuse 22 mit einem Außengewinde auf, welches in eine entsprechende Bohrung im Block 21 einschraubbar ist. Das Druckbegrenzungsventil 2 weist einen axial gegen die Kraft der Betätigungseinrichtung 15 in einer Kolbenkammer 23 des Ventilgehäuses 22 verfahrbaren Ventilkolben 24 auf. Das Ventilgehäuse 22 weist eine Vielzahl an radial am Umfang des Ventilgehäuses 22 angeordneten Eingangsanschlüssen 25 auf. Wie dargestellt münden die Eingangsanschlüsse 25 in eine entsprechende erste im Block 21 ausgebildete Kammer 26. In die erste Kammer 26 mündet ein erster Anschluss 27, an welchem die zweite Lastdruckleitung 9 angeschlossen ist.The pressure relief valve 2 is shown as shown Figs. 5 and 6 For example, screwed into a block 21 of the proportional slide valve 1, which is only partially shown. For this purpose, the pressure relief valve 2 has a valve housing 22 with an external thread, which can be screwed into a corresponding hole in the block 21. The pressure relief valve 2 has a valve piston 24 which can be moved axially against the force of the actuating device 15 in a piston chamber 23 of the valve housing 22. The valve housing 22 has a plurality of input connections 25 arranged radially on the circumference of the valve housing 22. As shown, the input connections 25 open into a corresponding first chamber 26 formed in the block 21. A first connection 27, to which the second load pressure line 9 is connected, opens into the first chamber 26.

Ferner weist das Ventilgehäuse 22 eine Vielzahl an ersten Verbindungsanschlüssen 28 auf, die radial am Umfang des Ventilgehäuses 22 angeordnet sind. Wie dargestellt münden die ersten Verbindungsanschlüsse 28 in eine zweite im Block 21 ausgebildete Kammer 29. In die zweite Kammer 29 mündet ein zweiter Anschluss 30, an welchem die Rücklaufleitung 6 angeschlossen ist.Furthermore, the valve housing 22 has a plurality of first connection connections 28 which are arranged radially on the circumference of the valve housing 22. The first ones flow as shown Connection connections 28 into a second chamber 29 formed in block 21. A second connection 30, to which the return line 6 is connected, opens into the second chamber 29.

Des Weiteren weist das Ventilgehäuse 22 einen zweiten Verbindunganschluss 31 auf. Der zweite Verbindungsanschluss 31 mündet in eine dritte im Block 21 ausgebildete Kammer 36. In die dritte Kammer 36 mündet ein dritter Anschluss 37, an welchem die Meldeleitungsanordnung 14 angeschlossen ist.Furthermore, the valve housing 22 has a second connection port 31. The second connection connection 31 opens into a third chamber 36 formed in block 21. A third connection 37, to which the signaling line arrangement 14 is connected, opens into the third chamber 36.

Der zweite Verbindungsanschluss 31 weist eine das Ventilgehäuse 22 axial durchsetzende und zur Bewegungsachse des Ventilkolbens 24 koaxiale Bohrung 32 auf. In der Bohrung 32 ist ein axial bewegliches Bewegungselement 33 angeordnet. In dem gezeigten Ausführungsbeispiel ist das Bewegungselement 33 eine Nadel mit einer Kegelfläche 34. Der zweite Verbindungsanschluss 31 weist eine entsprechende und dem Ventilkolben 24 zugewandte Anlagefläche 35 in Form einer Sitzfläche auf. Mithin bildet das Bewegungselement 33 mit seiner Kegelfläche 34 gemeinsam mit der Anlagefläche 35 ein Sitzventil aus, vgl. hierzu auch Fig. 7. Ferner hat diese Anordnung den Vorteil, dass das Bewegungselement 33 sicher in der Bohrung 32 gehalten wird, beispielsweise bei der Montage des Druckbegrenzungsventils 2.The second connection port 31 has a bore 32 which passes axially through the valve housing 22 and is coaxial with the axis of movement of the valve piston 24. An axially movable movement element 33 is arranged in the bore 32. In the exemplary embodiment shown, the movement element 33 is a needle with a conical surface 34. The second connection connection 31 has a corresponding contact surface 35 in the form of a seat facing the valve piston 24. The movement element 33 therefore forms a seat valve with its conical surface 34 together with the contact surface 35, see also Fig. 7 . Furthermore, this arrangement has the advantage that the movement element 33 is held securely in the bore 32, for example when assembling the pressure relief valve 2.

Der Ventilkolben 23 wird durch die von der Betätigungseinrichtung 15 erzeugte Kraft in der in Fig. 5 gezeigten Sperrstellung gehalten. In dieser Stellung kann kein Hydraulikfluid von den Eingangsanschlüssen 25 zu den ersten Verbindungsanschlüssen 28 strömen. Der Strömungsweg zwischen den Eingangsanschlüssen 25 und den ersten Verbindungsanschlüssen 28 ist gesperrt.The valve piston 23 is driven by the force generated by the actuating device 15 in the in Fig. 5 locked position shown. In this position, no hydraulic fluid can flow from the input ports 25 to the first connection ports 28. The flow path between the input ports 25 and the first connection ports 28 is blocked.

Sobald Druck in der zweiten Lastdruckleitung 9 über den ersten Anschluss 27 auf den Ventilkolben 24 wirkt, wird dieser proportional zum Druck axial gegen die Betätigungskraft der Betätigungseinrichtung 15 in der Kolbenkammer 23 bewegt. Mithin wird ein Strömungsweg zwischen den Eingangsanschlüssen 25 und den Verbindungsanschlüssen 28 freigegeben. Zusätzlich zum Druck am ersten Anschluss 27 wirkt auf den Ventilkolben 24 in Aufsteuerrichtung bzw. in Richtung der Offenstellung der in der Meldeleitungsanordnung 14 vorherrschende Vorsteuerdruck. Dieser bewegt das Bewegungselement 33 in axialer Richtung, sodass es eine Kraft auf den Ventilkolben 24 überträgt. Somit wirkt der Vorsteuerdruck ebenfalls in Aufsteuerrichtung des Druckbegrenzungsventils 2 auf den Ventilkolben 24. Die Kraft "hilft" beim Öffnen des Druckbegrenzungsventils 2 und ist ein Produkt aus Vorsteuerdruck und Querschnittsfläche des Bewegungselements 33.As soon as pressure in the second load pressure line 9 acts on the valve piston 24 via the first connection 27, it is moved axially in proportion to the pressure against the actuating force of the actuating device 15 in the piston chamber 23. A flow path between the input ports 25 and the connection ports 28 is therefore opened. In addition to the pressure at the first connection 27, the pilot control pressure prevailing in the signaling line arrangement 14 acts on the valve piston 24 in the opening direction or in the direction of the open position. This moves the movement element 33 in the axial direction so that it transmits a force to the valve piston 24. The pilot pressure therefore also acts on the valve piston 24 in the opening direction of the pressure relief valve 2. The force “helps” in opening the pressure relief valve 2 and is a product of the pilot pressure and the cross-sectional area of the movement element 33.

Beim Schließen des Druckbegrenzungsventils 2 bewegt sich der Ventilkolben 24 axial in der Kolbenkammer 23 in Richtung des zweiten Verbindungsanschlusses 31 in die in Fig. 5 gezeigte Sperrstellung. Hierbei steigt der Druck in der Kolbenkammer 23 an unddas Bewegungselement 33 wird ebenfalls axial bewegt, bis die Kegelfläche 34 sitzdicht auf der Anlagefläche 35 aufliegt. Hierdurch wird die Spaltleckage zwischen Bohrung 32 und Bewegungselement 33 reduziert. Dies ermöglicht es, dass die Bewegung des Ventilkolbens 24 beim Schließen des Druckbegrenzungsventils 2 gedämpft werden kann.When the pressure relief valve 2 is closed, the valve piston 24 moves axially in the piston chamber 23 in the direction of the second connection port 31 Fig. 5 locking position shown. The pressure in the piston chamber 23 increases and the movement element 33 is also moved axially until the conical surface 34 rests tightly on the contact surface 35. This reduces the gap leakage between bore 32 and movement element 33. This makes it possible for the movement of the valve piston 24 to be dampened when the pressure relief valve 2 is closed.

BezugszeichenlisteReference symbol list

11
Proportional-SchieberventilProportional slide valve
2, 2`2, 2`
DruckbegrenzungsventilPressure relief valve
33
VorsteuerungPilot control
44
SchieberkolbenSlide piston
55
DruckanschlussPressure connection
66
Rücklaufleitungreturn line
77
LastdruckausgangLoad pressure output
88th
erste Lastdruckleitungfirst load pressure line
99
zweite Lastdruckleitungsecond load pressure line
1010
LastdruckeingangLoad pressure input
1111
WechselventilShuttle valve
1212
ZulaufreglerInlet regulator
1313
Düsejet
1414
MeldeleitungsanordnungReporting line arrangement
14a14a
erste Meldeleitungfirst reporting line
14b14b
zweite Meldeleitungsecond reporting line
14c14c
WechselventilShuttle valve
1515
BetätigungseinrichtungActuating device
1616
dritte Lastdruckleitungthird load pressure line
1717
erstes Rückschlagventilfirst check valve
1818
zweites Rückschlagventilsecond check valve
1919
vierte Lastdruckleitungfourth load pressure line
2020
drittes Rückschlagventilthird check valve
2121
Blockblock
2222
VentilgehäuseValve housing
2323
KolbenkammerPiston chamber
2424
VentilkolbenValve piston
2525
EingangsanschlussInput port
2626
erste Kammerfirst chamber
2727
erster Anschlussfirst connection
2828
erster Verbindungsanschlussfirst connection port
2929
zweite Kammersecond chamber
3030
zweiter Anschlusssecond connection
3131
zweiter Verbindungsanschlusssecond connection port
3232
Bohrungdrilling
3333
BewegungselementMovement element
3434
Kegelflächeconical surface
3535
Anlageflächeinvestment area
3636
dritte Kammerthird chamber
3737
dritter Anschlussthird connection
100100
Hydrauliksystem gemäß der ersten AusführungsformHydraulic system according to the first embodiment
100'100'
Hydrauliksystem gemäß der zweiten AusführungsformHydraulic system according to the second embodiment
100"100"
Hydrauliksystem gemäß der dritten AusführungsformHydraulic system according to the third embodiment
100‴100‴
Hydrauliksystem gemäß der vierten AusführungsformHydraulic system according to the fourth embodiment
AA
erster Druckausgangfirst print output
Bb
zweiter Druckausgangsecond pressure output
NN
NeutralstellungNeutral position
S1S1
erste Schaltstellungfirst switching position
S2S2
zweite Schaltstellungsecond switching position

Claims (14)

  1. Proportional spool valve (1) having a spool piston (4) which can be switched from a neutral position (N) into at least one first switching position (S1) via a pilot control (3) which generates a pilot control force, a pressure port (5), a first pressure outlet (A), a return line (6) and a first load pressure line (8) which is connected to a load pressure outlet (7),
    wherein the pressure port (5) is connected to the first pressure outlet (A) and the first load pressure line (8) in the first switching position (S1),
    wherein a second load pressure line (9) branches off from the first load pressure line (8),
    wherein the second load pressure line (9) is connected to the return line (6) and a pressure limiting valve (2) is arranged in the second load pressure line (9),
    characterized in that
    the pilot control force acts as an additional force component in the opening direction of the pressure limiting valve (2), so that the force required to open the pressure limiting valve (2) against an actuating device (15) of the pressure limiting valve (2) is reduced.
  2. Proportional spool valve (1) according to claim 1,
    characterized in that
    the pilot control (3) is a hydraulic pilot control (3) and the pilot control force is a pilot control pressure.
  3. Proportional spool valve (1) according to claim 2,
    characterized in that
    a signal line assembly (14) connects the pilot control (3) to the pressure limiting valve (2) so that the pilot pressure is signaled to the pressure limiting valve (2) via the signal line assembly (14).
  4. Proportional spool valve (1) according to any of the previous claims,
    characterized in that
    the proportional spool valve (1) has a second pressure outlet (B) and can be switched from the neutral position (N) to a second switching position (S2) via the pilot control (3), the pressure port (5) being connected to the second pressure outlet (B) and the first load pressure line (8) in the second switching position (S2).
  5. Proportional spool valve (1) according to any of the previous claims,
    characterized in that
    a third load pressure line (16) branches off downstream of the spool piston (4) and upstream of the first pressure outlet (A) in the flow direction to the first pressure outlet (A), the third load pressure line (16) opening into the second load pressure line (9) upstream of the pressure limiting valve (2), and a first check valve (17) being arranged in the third load pressure line.
  6. Proportional spool valve (1) according to claim 5,
    characterized in that
    a second check valve (18) is arranged in the second load pressure line (9) upstream of the junction of the third load pressure line (16).
  7. Proportional spool valve (1) according to any one of the preceding claims 5 or 6,
    characterized in that
    the first check valve (17) is a spring-loaded check valve.
  8. Proportional spool valve (1) according to claim 4 and any of the preceding claims 5 to 7,
    characterized in that
    a fourth load pressure line (19) branches off downstream of the spool piston (4) and upstream of the second pressure outlet (B) in the flow direction to the second pressure outlet (B), the fourth load pressure line (19) opening into the second load pressure line (9) upstream of the pressure limiting valve (2'), and a third check valve (20) being arranged in the fourth load pressure line (19).
  9. Proportional spool valve (1) according to claim 8,
    characterized in that
    the third check valve (20) is a spring-loaded check valve.
  10. Proportional spool valve (1) according to any of the previous claims,
    characterized in that the pressure limiting valve (2) comprises a valve housing (22), the actuating device (15), and a valve piston (24) axially movable in a piston chamber (23) of the valve housing (22), wherein the valve housing (22) comprises at least one inlet port (25) and at least one first connecting port (28) and the valve piston (24) blocks or proportionally releases a flow path between the inlet port (25) and the first connecting port (28) by moving the valve piston (24) between a blocking position and an open position in the piston chamber (23) against an actuating force generated by the actuating device (15),
    wherein the valve housing (22) has a second connecting port (31), wherein a pressure at the second connecting port (31) acts on the valve piston (24) in the open direction of the pressure limiting valve (2) against the actuating force of the actuating device (15).
  11. Proportional spool valve (1) according to claim 10,
    characterized in that
    the second connecting port (31) has a bore (32) passing through the valve housing (22) in the axial direction.
  12. Proportional spool valve (1) according to claim 11,
    characterized in that
    an axially movable motion element (33) is arranged in the bore (32), the motion element (33) transmitting a force acting in the direction of the open position to the valve piston (24) when pressure is applied to the second connecting port (31).
  13. Proportional spool valve (1) according to claim 12,
    characterized in that
    the motion element (33) has a conical surface (34), and in that the second connecting port (31) has a corresponding contact surface (35) facing the valve piston (24), the contact surface (35) preferably being a seat surface.
  14. A hydraulic system (100, 100', 100") comprising a proportional spool valve (1) according to any one of claims 1 to 13.
EP21180886.0A 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system Active EP3957865B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP23192544.7A EP4254126A3 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102020210441.7A DE102020210441A1 (en) 2020-08-17 2020-08-17 Proportional spool valve with a pressure relief valve, pressure relief valve and hydraulic system

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP23192544.7A Division EP4254126A3 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system
EP23192544.7A Division-Into EP4254126A3 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system

Publications (3)

Publication Number Publication Date
EP3957865A2 EP3957865A2 (en) 2022-02-23
EP3957865A3 EP3957865A3 (en) 2022-03-30
EP3957865B1 true EP3957865B1 (en) 2023-09-27

Family

ID=76971609

Family Applications (2)

Application Number Title Priority Date Filing Date
EP21180886.0A Active EP3957865B1 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system
EP23192544.7A Pending EP4254126A3 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP23192544.7A Pending EP4254126A3 (en) 2020-08-17 2021-06-22 Proportional slide valve with a pressure limiting valve and hydraulic system

Country Status (2)

Country Link
EP (2) EP3957865B1 (en)
DE (1) DE102020210441A1 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3605980A1 (en) * 1985-03-05 1986-10-16 Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid Proportional valve with pressure-difference balance

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4420704C2 (en) * 1994-06-14 2002-07-04 Brueninghaus Hydromatik Gmbh Hydrostatic drive, especially for the slewing gear of an excavator
DE10115650A1 (en) 2001-03-29 2002-10-02 Bosch Gmbh Robert Hydraulic control device
DE10127904B9 (en) * 2001-06-08 2013-01-17 Linde Material Handling Gmbh Control valve means
DE102004063044B4 (en) * 2004-12-22 2006-12-21 Sauer-Danfoss Aps Hydraulic control
DE102012001549A1 (en) * 2012-01-26 2013-08-01 Robert Bosch Gmbh Load-sensing valve assembly with pressure control
DE102013015774A1 (en) 2013-09-21 2015-03-26 Bieri Hydraulik Ag Valve device and hydraulic system
DE102014102336A1 (en) 2014-02-24 2015-08-27 Linde Hydraulics Gmbh & Co. Kg Control valve device with a floating position
EP3018364B1 (en) * 2014-11-10 2017-08-16 HAWE Hydraulik SE Control device with sliding piston
CN208565105U (en) 2017-11-22 2019-03-01 长安大学 A kind of device for eliminating load sensitive system hydraulic shock

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3605980A1 (en) * 1985-03-05 1986-10-16 Barmag Barmer Maschinenfabrik Ag, 5630 Remscheid Proportional valve with pressure-difference balance

Also Published As

Publication number Publication date
EP4254126A3 (en) 2023-12-20
EP4254126A2 (en) 2023-10-04
EP3957865A3 (en) 2022-03-30
DE102020210441A1 (en) 2022-02-17
EP3957865A2 (en) 2022-02-23

Similar Documents

Publication Publication Date Title
EP1781952B1 (en) Hydraulic control arrangement
EP0883753B1 (en) Load-holding brake valve
EP1629336B1 (en) Valve
EP2294331B1 (en) Hydraulic valve device
DE19831595B4 (en) Hydraulic circuit
DE102006040234A1 (en) LS control arrangement
EP1984629B1 (en) Hydraulic control arrangement with regeneration and lowering brake valve
EP3957865B1 (en) Proportional slide valve with a pressure limiting valve and hydraulic system
EP3625457B1 (en) Control device for supplying at least one hydraulic consumer with fluid
EP1736671B1 (en) Load sensing control system and load sensing directional valve
DE19646427B4 (en) valve assembly
DE102012015356A1 (en) Valve, in particular pilot-operated proportional directional seat valve
DE3611244A1 (en) Flow-control valve
DE3225132A1 (en) Hydraulic safety brake valve
WO1999040349A1 (en) Pressure control valve
EP1351879B1 (en) Fork lift with control device
EP2157320B1 (en) Hydraulic device for a hydro motor
EP0823559A2 (en) Hydraulic control device
DE102020212201B4 (en) Separate hydraulic damping module and load holding valve with separate hydraulic damping module
EP2157321A1 (en) Screw-in screw connection
EP2050992B1 (en) Valve device
EP1452744B1 (en) Hydraulic control device
DE102020209387B3 (en) Preselection valve, hydraulic valve bank and hydraulic control device
DE102017130485B4 (en) Hydraulic circuit arrangement for lifting and lowering a load
DE3222106A1 (en) Hydraulic control arrangement

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

RIC1 Information provided on ipc code assigned before grant

Ipc: G05D 16/00 20060101ALI20220223BHEP

Ipc: F15B 13/04 20060101ALI20220223BHEP

Ipc: F15B 13/043 20060101ALI20220223BHEP

Ipc: F15B 13/02 20060101ALI20220223BHEP

Ipc: F15B 11/16 20060101AFI20220223BHEP

17P Request for examination filed

Effective date: 20220323

RBV Designated contracting states (corrected)

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20221020

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230523

INTG Intention to grant announced

Effective date: 20230614

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502021001554

Country of ref document: DE

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG9D

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

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20231228

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

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20231227

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20231228

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

REG Reference to a national code

Ref country code: NL

Ref legal event code: MP

Effective date: 20230927

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

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20230927

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

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20240127