DK164136B

DK164136B - PRESSURE DEVICING DEVICE FOR A ENGINE CONTAINING HYDRAULIC SYSTEM

Info

Publication number: DK164136B
Application number: DK541588A
Authority: DK
Inventors: Svend Erik Thomsen; Jes Valdemar Vogler; Harry Emil Pedersen
Original assignee: Danfoss As
Priority date: 1987-10-03
Filing date: 1988-09-29
Publication date: 1992-05-11
Also published as: DK541588A; DK164136C; DE3733517C2; DE3733517A1; DK541588D0

Description

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Opfindelsen angår en trykpåvirkningsindretning for et en motor indeholdende hydraulisk system, med en trykventil til reduktion af trykstød, hvis indgang over en skifteventil er forbundet med motorens to tilslutningsledninger, og hvis 5 indstillingsorgan i åbningsretning er belastet af det i et første trykrum virkende indgangstryk og i lukkeretning af en tilbagestillingsfjeder og et i et andet trykrum virkende modtryk, hvorved det andet trykrum er forbundet med en trykakkumulator og over en drossel med det første trykrum, og 10 hver tilslutningsledning er forbundet med trykventilens udgang.BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a pressure actuator for a motor containing hydraulic system, with a pressure valve for reducing pressure shock, the inlet of which is connected to the two connection lines of the motor, and whose adjusting means in the opening direction is loaded by the input pressure acting closing direction of a reset spring and a counterpressure acting in a second pressure chamber, whereby the second pressure space is connected to a pressure accumulator and over a throttle with the first pressure space, and each connecting line is connected to the outlet of the pressure valve.

Ved en kendt trykpåvirkningsindretning af denne art (DE-PS 28 38 940) er trykventilens udgang forbundet med beholderen.In a known pressure actuator of this kind (DE-PS 28 38 940) the outlet of the pressure valve is connected to the container.

På denne måde kan trykstød reduceres, som optræder, når der 15 udøves ydre stødkræfter på motoren, eller når der optræder pludselige ændringer i det hydrauliske system, fx ved lukning af en ventil. I stationær tilstand er modtrykket lig med indgangstrykket. Når der optræder et trykstød, åbner ventilen, fordi trykstøddet ikke forplanter sig over droslen 20 til det andet trykrum. Opretholdes den nye trykamplitude imidlertid i længere tid, sker der over droslen en trykudligning, og trykventilen lukker igen. Ved samvirkningen af drossel og trykakkumulator fås en dæmpning, således at der ikke optræder oversvingninger. Dette system har dog den 25 ulempe, at ved langsomme trykændringer stiger trykket i rummet, og ved overskridelse af fjedertrykket forskydes den elastiske væg til højre mod fjederens kraft, uden at en trykbegrænsning finder sted. Når fjederen er fuldstændig komprimeret, ligger ventilen mod anslaget og kan ikke mere 30 opfylde sin funktion.In this way, compression shocks can be reduced which occur when external shock forces are exerted on the engine or when sudden changes in the hydraulic system occur, for example, by closing a valve. In the stationary state, the back pressure is equal to the input pressure. When a pressure shock occurs, the valve opens because the pressure shock does not propagate across the throttle 20 to the other pressure chamber. However, if the new pressure amplitude is maintained for a longer time, a pressure equalization occurs over the throttle and the pressure valve closes again. At the interaction of the throttle and pressure accumulator a damping is obtained so that no oscillations occur. However, this system has the disadvantage that, with slow pressure changes, the pressure in the room rises, and when the spring pressure is exceeded, the elastic wall is shifted to the right against the force of the spring without a pressure limitation taking place. When the spring is completely compressed, the valve is against the stop and can no longer perform its function.

Det er endvidere ved hydrauliske anlæg kendt (DE-PS 23 18 962) at forbinde hver tilslutningsledning af en motor med beholderen såvel over en sugeventil som over en overtryksventil. Sugeventilen er en i retning af tilslutningsFurthermore, it is known in hydraulic systems (DE-PS 23 18 962) to connect each connecting line of a motor to the container both over a suction valve and over a pressure valve. The suction valve is one in the direction of connection

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2 ledningen åbnende kontraventil. Overtryksventilen er en i retning af beholderen åbnende, fjederbelastet kontraventil.2 wire opening check valve. The overpressure valve is a spring-loaded check valve opened in the direction of the container.

Med overtryksventilen kan kun spidsen af et trykstød reduceres. Når der på grund af et ydre stød i et motor-cylinderrum 5 optræder undertryk eller kavitation, skal væske suges til gennem efterfyldningsventilen. Alligevel er efterfyldningen utilstrækkelig, fordi efterfyldningsventilen først åbner, når trykket i cylinderrummet er faldet under beholdertrykket med en værdi, der tager hensyn til ledningsmodstanden.With the pressure relief valve, only the tip of a pressure shock can be reduced. When, due to an external shock in an engine cylinder compartment 5, underpressure or cavitation occurs, fluid must be drawn in through the backfill valve. Still, the backfill is insufficient because the backfill valve only opens when the pressure in the cylinder compartment has dropped below the container pressure with a value taking into account the conduction resistance.

10 DE-PS 33 42 282 beskriver en ventilindretning til kontrol af en hydraulikmotors arbejdsbevægelse. I dette skrift foreslås anvendelsen af kontraventiler i tilslutningsledninger for at muliggøre en eftersugning. Dette skrift angiver også to overtryksventiler, som imidlertid tjener til, trods lukkede 15 kontraventiler, at muliggøre en bortstrømning af hydraulikvæsken. Mellem de to overtryksventiler findes en forbindelse til tanken.10 DE-PS 33 42 282 discloses a valve device for controlling the working motion of a hydraulic motor. This publication proposes the use of non-return valves in connection pipes to enable a suction. This specification also specifies two pressure valves, which, however, despite closed 15 non-return valves, allow a hydraulic fluid to flow out. Between the two pressure valves there is a connection to the tank.

Formålet med opfindelsen er at angive en trykpåvirkningsindretning af den i indledningen beskrevne art, med hvilken ef-20 terfyldningen forbedres ved optræden af ydre stødbelastninger på motoren, og som samtidig tillader en simpel overtryksbegrænsning .The object of the invention is to provide a pressure actuator of the kind described in the preamble, with which the backfill is improved by the occurrence of external shock loads on the motor and which at the same time allows a simple overpressure limitation.

Denne opgave løses ifølge opfindelsen ved, at hver forbindelse i en fælles udgang til tilslutningsledningen har en 25 mod denne åbnende kontraventil, og det andet trykrum er over en enkelt overtryksventil forbundet med en systemdel med lavt tryk.This task is solved according to the invention in that each connection in a common outlet to the connection line has a 25 against this open check valve and the second pressure chamber is connected over a single pressure valve to a low pressure system part.

Når der ved et ydre stød på motorens aktiveringsorgan optræder et trykstød i det ene cylinderrum, og trykventilen som 30 følge deraf åbner, føres trykvæsken ikke til beholderen, men over den tilhørende kontraventil til motorens andet cylinderrum. Der sker derfor en tvangsefterfyldning uafhængigt afWhen an external shock on the actuator of the engine causes a pressure shock in one cylinder compartment and the pressure valve as a result opens, the pressure fluid is not fed to the container, but over the associated check valve to the other cylinder compartment. Therefore, there is a forced replenishment independent of

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3 trykkets absolutte værdi. Undertryks- eller kavitationsfore-komster er med sikkerhed udelukket. Denne forbindelse mellem de to tilslutningsledninger åbnes imidlertid kun, når trykventilen reagerer. Det forhindres altså ikke, at den ene el-5 ler den anden tilslutningsledning fører undertryk i normal drift for at udøve negative styrekræfter på motoren. En enkelt overtryksventil er tilstrækkelig til begge tilslutningsledninger. Ganske vist reduceres overtrykket ved formindskelse af det andet trykrum. Da dette imidlertid er for-10 bundet med det første trykrum over droslen, vender trykventilen derefter tilbage til lukkestillingen.3 the absolute value of the pressure. Suppression or cavitation occurrences are certainly excluded. However, this connection between the two connection lines is only opened when the pressure valve responds. Thus, it is not prevented that one or the other connection line causes negative pressure in normal operation to exert negative control forces on the motor. A single pressure valve is sufficient for both connecting lines. Admittedly, the overpressure is reduced by decreasing the second pressure space. However, since this is connected to the first pressure chamber above the throttle, the pressure valve then returns to the closing position.

Når trykstøddet optræder på grund af en ændring i det hydrauliske system, fx ved hurtig udstyring af en styreenhed, nedsættes trykstøddets virkning på motoren. For ikke kun 15 trykstigningen i cylinderrummet på tilgangssiden reduceres, men samtidig fremkaldes i det andet cylinderrum en trykstigning. Dermed minimeres trykdifferensen mellem de to tilslutningsledninger og forhindrer, at motoren gennemfører for hurtige eller pludselige bevægelser.When the thrust shock occurs due to a change in the hydraulic system, for example by the quick equipping of a control unit, the effect of the thrust shock on the engine is reduced. Not only is the pressure increase in the cylinder space on the supply side reduced, but at the same time in the second cylinder space a pressure increase is induced. This minimizes the pressure difference between the two connection lines and prevents the motor from performing too fast or sudden movements.

20 Det er særlig gunstigt, at de med de to tilslutningsledninger forbundne cylinderrum af motoren er dimensioneret således, at de under motorens drift undergår lige store, men modsatte volumenændringer. Fx drejer det sig om en stempelmotor med gennemgående stempelstang. Der kan også være an-25 bragt motorer med over kors forbundne differentialcylindre eller rotationsmotorer. I dette tilfælde fås særlig gunstige forhold, fordi den i det ene cylinderrum fortrængte trykvæskemængde er lig med den trykvæskemængde, der optages af det andet cylinderrum. Man kan så give fuldstændig afkald på de 30 sædvanlige, med beholderen forbundne suge- og overtryksventiler.20 It is particularly advantageous that the cylinder compartments of the motor connected to the two connecting lines are dimensioned so that during the operation of the motor they undergo equal but opposite volume changes. For example, it is a piston engine with a through piston rod. Engines may also be provided with cross-linked differential cylinders or rotary motors. In this case, particularly favorable conditions are obtained because the amount of pressurized fluid in one cylinder compartment is equal to the amount of pressurized fluid that is taken up by the other cylinder compartment. The 30 conventional suction and overpressure valves connected to the container can then be completely dispensed with.

Især kan overtryksventilens udgang være forbundet med trykventilens udgang. Den til reduktion af overtrykket udstrømIn particular, the pressure relief valve outlet may be connected to the pressure relief valve outlet. The for reducing the overpressure outflow

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4 mende trykvæskemængde ledes derefter bort over en af kontraventilerne og understøtter trykket i det ikke af overtrykket belastede cylinderrum af motoren.4 amount of pressurized fluid is then passed over one of the check valves and supports the pressure in the unpressurized cylinder space of the engine.

I det enkleste tilfælde behøver trykakkumulatoren kun at 5 sikre, at ventilens indstillingsorgan kan gennemføre den til åbningen krævede bevægelse. Hertil var de almindeligvis i trykolien indeholdte små luftblærer tilstrækkelige, når volumenet af det andet trykrum eller de dermed forbundne rum har en bestemt mindste størrelse, fx ca. 300 - 400 cm3, især 10 kan trykakkumulatoren derfor have et fuldstændig med olie fyldt akkumulatortrykkammer. Forskellige andre udførelser for en anvendelig trykakkumulator er vist i DE-PS 28 38 940.In the simplest case, the pressure accumulator need only ensure that the valve adjusting means can perform the movement required for the opening. For this, the small air bladders usually contained in the pressure oil were sufficient when the volume of the second pressure chamber or the associated compartments is of a certain minimum size, e.g. 300-400 cm3, especially 10, the pressure accumulator may therefore have a complete oil-filled accumulator pressure chamber. Various other designs for a useful pressure accumulator are shown in DE-PS 28 38 940.

Det er herved særlig anbefalelsesværdige at trykakkumulatoren har en gastrykfjeder. Fortrinsvis adskiller en membran 15 trykakkumulatorens trykmiddelrum fra gaspuden. Dette tillader en særlig god tilpasning mellem trykændringer og volumenændringer og derfor en god dæmpning.It is hereby particularly recommended that the pressure accumulator has a gas pressure spring. Preferably, a membrane 15 separates the pressure accumulator pressure medium space from the gas pad. This allows a particularly good fit between pressure changes and volume changes and therefore a good damping.

Det er også gunstigt, at i det mindste trykakkumulatoren, trykventilen, droslen, skifteventilen og kontraventilerne er 20 sammenfattet i en ventilblok. Frem for alt kan ventilblokkens dimensioner holdes på den sædvanlige størrelse ved anvendelse af det fuldstændigt fyldte trykakkumulatorkammer.It is also advantageous that at least the pressure accumulator, pressure valve, throttle, shift valve and check valves are summed in a valve block. Above all, the dimensions of the valve block can be maintained at the usual size using the fully filled pressure accumulator chamber.

Endvidere kan droslen være shuntet af en mod indgangen åbnende kontraventil. Med denne i og for sig kendte forholds-25 regel aflastes det andet trykrum hurtigt efter reduktionen af et trykstød, således at det straks igen står til rådighed for reduktionen af et yderligere trykstød.Furthermore, the throttle may be shunted by a check valve opening towards the entrance. With this known per se rule, the second pressure chamber is relieved quickly after the reduction of a pressure shock, so that it is immediately available for the reduction of a further pressure shock.

Opfindelsen forklares nærmere nedenstående ved hjælp af et på tegningen vist, foretrukket udførelseseksempel. Den ene-30 ste tegning viser diagrammet for en hydrostatisk styreindretning med trykpåvirkningsindretningen ifølge opfindelsen.The invention is further explained below by means of a preferred embodiment shown in the drawing. The only drawing shows the diagram of a hydrostatic control device with the pressure actuating device according to the invention.

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Et styreapparat 1 kan aktiveres af et rat 2. Dets pumpetilslutning P er forbundet med en pumpe 3, dets tanktilslutning T er forbundet med en beholder 4. De to arbejdstilslutninger L og R er hver over en tilslutningsledning 5 og 6 forbundet 5 med de to rum 7 og 8 af en styremotor 9. Dennes stempel 11, som kan bevæges frem og tilbage i en cylinder 10, er forsynet med en gennemgående stempelstang 12, som er forbundet med styrestængerne. Ved en bevægelse af stemplet 11 forøges volumenet i det ene cylinderrum 7 i samme grad, som volume-10 net formindskes i det andet cylinderrum 8.A control unit 1 can be actuated by a steering wheel 2. Its pump connection P is connected to a pump 3, its tank connection T is connected to a container 4. The two working connections L and R are connected to the two compartments over a connection line 5 and 6 respectively. 7 and 8 of a steering motor 9. Its piston 11, which can be moved back and forth in a cylinder 10, is provided with a continuous piston rod 12 which is connected to the guide rods. By moving the plunger 11, the volume in one cylinder compartment 7 is increased to the same degree as the volume 10 net decreases in the second cylinder compartment 8.

En trykventil 13 har et stempel 14, som samtidig tjener som indstillingsorgan og som lukkestykke. Det belastes på sin ene ende af indgangstrykket PE i et første trykrum 15 og på sin anden ende af en svag tilbagestillingsfjeder 16 og et 15 modtryk Pq i et andet trykrum 17 med samme effektive tværsnit.A pressure valve 13 has a piston 14 which simultaneously serves as an adjusting means and as a closing piece. It is loaded at one end of the input pressure PE in a first pressure chamber 15 and at its other end by a weak reset spring 16 and a backpressure Pq in a second pressure chamber 17 having the same effective cross-section.

I hviletilstand er stemplet 14 understøttet på et anslag 18.In the idle state, the piston 14 is supported on a stop 18.

Det første trykrum 15 danner derfor trykventilens 13 indgang 19. Udgangen 20 dannes af et ringrum. Indgangen 19 er med en 20 skifteventils 22 udgang 21 forskydelig i en cylinder 24, ved hvis ender en hver med en tilslutningsledning 5 og 6 forbundet indgang 25 og 26 er anbragt. Da stemplet 23 forskydes under indflydelse af trykdifferensen mellem tilslutningsledningerne 5 og 6, forbindes indgangen 25 og 26 med det højere 25 tryk med trykventilens 13 indgang 19.Therefore, the first pressure chamber 15 forms the inlet 19. The pressure valve 13 is formed by an annulus. The inlet 19 is slidable with the output 21 of a switching valve 22 in a cylinder 24, at whose ends each of the inputs 25 and 26 connected to a connection line 5 and 6 are arranged. As the piston 23 is displaced under the influence of the pressure difference between the connection lines 5 and 6, the inputs 25 and 26 are connected to the higher 25 pressure with the input 19 of the pressure valve 13.

Desuden er tilslutningsledningen 5 over en mod den åbnende kontraventil 27 og tilslutningsledningen 6 over en mod den åbnende kontraventil 28 forbundet med trykventilens 13 udgang 20.In addition, the connection line 5 over one against the opening check valve 27 and the connection line 6 over one against the opening check valve 28 are connected to the outlet 20 of the pressure valve 13.

30 Det andet trykrum 17 står over en drossel 29 og en hermed parallelkoblet mod indgangen 19 åbnende kontraventil 30 i forbindelse med det første trykrum 15. Droslen 29 kan væreThe second pressure compartment 17 faces a throttle 29 and a coupling parallel to the inlet 19 opening 30 in connection with the first pressure compartment 15. The throttle 29 may be

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6 indstillelig. Kontraventilen 30 kan vare belastet af en indstillelig fjeder.6 adjustable. The check valve 30 may be loaded by an adjustable spring.

Det andet trykrum 17 står endvidere i forbindelse med en trykakkumulator 31. Denne har et vaskerum 32 og et med tryk-5 luft fyldt rum 33/ som er adskilt fra hinanden ved hjalp af en membran 34. De to rum 32 og 33 kan også ers'tattes af et fuldstændigt med olie fyldt akkumulatortrykkammer. Desuden står det andet trykrum 17 over en overtryksventil 35, som er belastet af en indstillelig fjeder 36, i forbindelse med be-10 holderen 4. Overtryksventilens 35 udgang kan i stedet for også være forbundet med ringrummet af trykventilens 13 udgang 20.The second pressure compartment 17 is also connected to a pressure accumulator 31. This has a wash compartment 32 and a compressed air filled compartment 33 which are separated from each other by means of a membrane 34. The two compartments 32 and 33 can also be replaced. taken from a complete oil-filled accumulator pressure chamber. In addition, the second pressure chamber 17 faces a pressure valve 35, which is loaded by an adjustable spring 36, in connection with the container 4. The outlet of the pressure valve 35 may instead be connected to the annulus of the outlet 20 of the pressure valve 13.

Delene 13 - 36 er sammenfattet i en ventilblok 37. Det er også gunstigt, at delene 13, 29, 31 og 35 simpelthen kun fo-15 refindes for at overvåge de to tilslutningsledninger 5 og 6 på samme måde. Mellem tilslutningsledningerne 5 og 6 kan der også være anbragt yderligere kendte ventilindretninger, som dog ikke spiller nogen rolle for forståelsen af den foreliggende opfindelse.Parts 13 - 36 are summarized in a valve block 37. It is also advantageous that parts 13, 29, 31 and 35 are simply refined to monitor the two connection lines 5 and 6 in the same way. Further known valve devices may also be arranged between the connection lines 5 and 6, which however play no role in understanding the present invention.

20 I et driftstilfælde antages det, at skifteventilen 22 har den viste stilling, fordi trykvæske tilføres over tilslutningsledningen 5 og bortledes over tilslutningsledningen 6; motorens 9 stempel 11 befinder sig derfor i den højre endestilling. Virker nu en stødagtig kraft fra højre på stempel-25 stangen 12, opstår der i cylinderrummet 7 et trykstød og i cylinderrummet 8 et tilsvarende undertryk. Trykstøddet fører til en forøgelse af indgangstrykket PE/ mens modtrykket PG foreløbig forbliver uændret. Derfor åbner trykventilen 13, så snart den svage tilbagestillingsfjeders 16 kraft er 30 overvundet, og der sker en trykmiddeludligning fra tilslutningsledningen 5 over skifteventilen 22, trykventilen 13 og kontraventilen 28 til tilslutningsledningen 6. Der kan derfor ikke optræde kavitationsforekomster. Tværtimod benyttesIn one operating case, it is assumed that the switching valve 22 has the position shown, because pressure fluid is supplied over the connection line 5 and discharged over the connection line 6; The piston 11 of the motor 9 is therefore in the right end position. If a shock-like force acts from the right on the piston-25 rod 12, a pressure shock occurs in the cylinder space 7 and in the cylinder space 8 a corresponding negative pressure. The pressure shock leads to an increase in the input pressure PE / while the back pressure PG remains unchanged for the time being. Therefore, as soon as the force of the weak reset spring 16 is overcome, the pressure valve 13 opens, and a pressure relief is effected from the connection line 5 over the shift valve 22, the pressure valve 13 and the check valve 28 to the connection line 6. No cavitation instances can therefore occur. On the contrary, it is used

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7 det til reduktion af trykstøddet bortledte trykmiddel umiddelbart til opfyldning af cylinderrummet 8.7 the pressure agent derived for reducing the pressure shock immediately for filling the cylinder space 8.

Sker trykstøddet i cylinderrummet 7 ved en aktivering i den hydrauliske kreds, så forhindres en for hurtig bevægelse af 5 stemplet 11 mod højre igen ved bortledning af trykmiddel på den skildrede måde til tilslutningsledningen 6. Da en tryk-opbygning i cylinderrummet 8 er forbundet med trykreduktionen i cylinderrummet 7, er trykfaldet ved motoren 9 minimeret.If the pressure shock occurs in the cylinder space 7 by an actuation in the hydraulic circuit, a too rapid movement of the piston 11 to the right is prevented again by the discharge of pressure means in the depicted way to the connection line 6. Since a pressure build-up in the cylinder space 8 is associated with the pressure reduction in the cylinder compartment 7, the pressure drop at the motor 9 is minimized.

10 Når styreapparatet 1 skal behandle en varig trykforhøjelse, træder trykventilen 13 i aktivitet ved en pludselig trykstigning. Da trykket mellem det første trykrum 15 og det andet trykrum 17 imidlertid udlignes over droslen 29, lukker trykventilen 13 efter kort tid, således at den blivende 15 trykstigning ikke påvirkes af trykventilen 13.10 When the controller 1 is to process a lasting pressure rise, the pressure valve 13 comes into operation in the event of a sudden increase in pressure. However, as the pressure between the first pressure chamber 15 and the second pressure chamber 17 is equalized above the throttle 29, the pressure valve 13 closes shortly afterwards, so that the future increase in pressure is not affected by the pressure valve 13.

Når der optræder et overtryk, altså en bestemt trykgrænseværdi overskrides, virker dette som følge af stemplets 14 forskydning i begge trykrum 15 og 17. Som følge heraf åbner overtryksventilen 35, således at overtrykket reduceres.When an overpressure occurs, that is, a certain pressure limit value is exceeded, this acts as a result of the displacement of the piston 14 in both pressure compartments 15 and 17. As a result, the overpressure valve 35 opens, so that the overpressure is reduced.

20 Når der optræder tryksvingninger i den trykførende tilslutningsledning 5 og 6, åbnes trykventilen 13 ved overskridelse af en bestemt amplitude. Herved samvirker trykakkumulatoren 31 og droslen 29 for at udøve en dæmpende virkning på svingningerne. Derfor er droslen 29 og trykket i gaspuden 33 for-25 trinsvis indstillelig.20 When pressure fluctuations occur in the pressure-carrying connection lines 5 and 6, the pressure valve 13 is opened by exceeding a certain amplitude. Thereby, the pressure accumulator 31 and the throttle 29 cooperate to exert a damping effect on the oscillations. Therefore, the throttle 29 and the pressure in the gas pad 33 are preferably adjustable.

Så snart trykket i tilslutningsledningen vender tilbage til den normale værdi, åbner kontraventilen 30 og aflaster det andet trykrum 17 pludseligt. Trykventilen 13 vender tilbage til lukkestillingen og står til rådighed for reduktionen af 30 et fornyet trykstød.As soon as the pressure in the connection line returns to its normal value, the check valve 30 opens and the second pressure chamber 17 suddenly relieves. The pressure valve 13 returns to the closing position and is available for the reduction of a renewed pressure shock.

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Tilbagestillingsfjederen 16 har kun en svag forspænding og en ringe stivhed. Dens opgave er kun at holde trykventilen lukket under de statiske forhold.The reset spring 16 has only a weak bias and a low stiffness. Its task is to keep the pressure valve closed only under the static conditions.

Trykventilen 13 åbner derfor enten, når indgangstrykket PE 5 stiger med for høj hastighed, eller når dets værdi overskrider en grænseværdi, som er indstillet af overtryksventilen 35.The pressure valve 13 therefore opens either when the inlet pressure PE 5 increases at too high a speed or when its value exceeds a limit value set by the pressure valve 35.

Trykakkumulatoren 31 kan erstattes af en fuldstændigt med trykvæske fyldt beholder, fordi luftblærerne i trykvæsken 10 tillader en bevægelse af indstillingsorganet 14. I stedet for membranen 34 kan der også benyttes et stempel, som er belastet af en fjeder. I stedet for den viste styremotor 9 kan der også være anvendt hvilke som helst andre motorer, fx drivmotorer, som kan dreje kontinuerligt, eller servomoto-15 rer.The pressure accumulator 31 can be replaced by a completely filled fluid-filled container because the air bladders in the pressure fluid 10 allow movement of the adjusting means 14. Instead of the diaphragm 34, a piston loaded by a spring can also be used. Instead of the control motor 9 shown, any other motors, for example, drive motors which can rotate continuously or servomotors, may also be used.

Claims

1. Pressure actuator for a hydraulic system containing motor (9), with a pressure relief valve (13) for reducing pressure shock, the inlet (19) of which is connected via a changeover valve (22) to the two connecting lines (5) of the motor (9). , 6) and whose adjusting means (14) in the opening direction is loaded by the input pressure (PE) acting in a first pressure chamber (15) and in the closing direction by a reset spring (16) and a counterpressure (Pq) acting in a second pressure chamber (17). ), wherein the second pressure chamber 10 (17) is connected to a pressure accumulator (31) and over a choke (29) to the first pressure space (15), and each connecting line (5, 6) is connected to the outlet of the pressure valve (13) ( 20), characterized in that each connection in a common outlet (20) to the connection line (5, 6) has one against this opening versus valve (27, 28) and the second pressure space (17) is above a single pressure relief valve (35) connected to a low pressure system part.

Pressure actuator according to claim 1, characterized in that the cylinder compartments (7, 8) of the motor (9) connected to the two connecting lines (5, 6) are dimensioned so that they undergo equal operation during the operation of the motor. but opposite volume changes.

Pressure actuating device according to claim 1 or 2, 25, characterized in that the output of the pressure valve (35) is connected to the output of the pressure valve (13).

Pressure actuator according to one of claims 1-3, characterized in that the pressure accumulator (31) has a complete oil-filled accumulator pressure chamber. DK 164136 B 10

Pressure actuator according to one of claims 1-4, characterized in that at least the pressure accumulator (31), the pressure valve (13), the throttle (29), the shift valve (22) and the check valves (27, 28) are summed in a valve block (37).

Pressure actuator according to one of claims 1 to 5, characterized in that the throttle (29) is supported by a check valve (30) which opens against the entrance (19).