EP0565552B1 - Non-leaking storage charging valve - Google Patents

Non-leaking storage charging valve Download PDF

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Publication number
EP0565552B1
EP0565552B1 EP92901393A EP92901393A EP0565552B1 EP 0565552 B1 EP0565552 B1 EP 0565552B1 EP 92901393 A EP92901393 A EP 92901393A EP 92901393 A EP92901393 A EP 92901393A EP 0565552 B1 EP0565552 B1 EP 0565552B1
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EP
European Patent Office
Prior art keywords
connection
control
valve
piston
inlet
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP92901393A
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German (de)
French (fr)
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EP0565552A1 (en
Inventor
Rüdiger JUNG
Harald BÄR
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Flutec Fluidtechnische Geraete GmbH
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Flutec Fluidtechnische Geraete GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/027—Installations or systems with accumulators having accumulator charging devices
    • F15B1/0275—Installations or systems with accumulators having accumulator charging devices with two or more pilot valves, e.g. for independent setting of the cut-in and cut-out pressures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2496—Self-proportioning or correlating systems
    • Y10T137/2559—Self-controlled branched flow systems
    • Y10T137/2574—Bypass or relief controlled by main line fluid condition
    • Y10T137/2605—Pressure responsive
    • Y10T137/2622—Bypass or relief valve responsive to pressure downstream of outlet valve
    • Y10T137/2625—Pilot valve

Definitions

  • the invention relates to an accumulator charging valve which is provided with a control piston for connecting an inlet feeding a hydraulic system to an outlet when an adjustable upper boost pressure is reached in the hydraulic system and for disconnecting this connection when an adjustable lower boost pressure is reached in the hydraulic system two switching positions separates the connection between inlet and outlet and in the other switching position establishes this connection, whereby a control connection connecting the hydraulic system with the accumulator charging valve is separated from the outlet by means of a separating device and a first and a second pilot valve are provided for setting the lower and the upper boost pressure is.
  • Accumulating store loading valves which are also referred to as shutdown valves, are usually used in Hydraulic systems or hydraulic circuits are used which have at least one hydraulic accumulator for keeping the pressure in the hydraulic system constant.
  • the respective hydraulic accumulator works in a range between a lower and an upper boost pressure, the respective pressure level of which can be adjusted, and is therefore freely selectable. If the charge pressure falls below or exceeds the lower or the upper charge pressure, the connection to the inlet ensuring the pressure oil supply is established or separated by means of the accumulator charge valve.
  • the adjustable difference between the lower and the upper boost pressure can be large but can also take very small values.
  • a storage charging valve of the same type has already been described in DE-PS 36 08 100.
  • this known accumulator charging valve has a control piston, the one piston part being designed as a separating device in each ingestible switching position of the control piston separating the connection between the control connection and the outlet which opens into the tank. Leakage occurs between the control connection and the outlet leading to the tank via an annular gap formed by this piston part. This reduces the boost pressure in the accumulator, which has the disadvantages described in DE-PS 36 08 100.
  • a non-generic embodiment of a hydraulic accumulator charging valve which has a main piston and a pilot control supplied with pressure medium from the inlet via a throttle point, with a pilot valve designed as a seat valve, which, after opening when the shutdown is reached, is released by an unlocking piston is held in the open position and so brings about the switch-off position of the main piston and this until it is reached of a lower cut-in pressure. Thanks to this training, there is no longer any loss of control oil, at least when the process is stressed.
  • the invention has for its object to provide a accumulator charging valve with freely adjustable switching points, which works with such a leak-free oil that the pressure in the hydraulic accumulator is kept constant even over a longer period of time.
  • the separating device has a closing piston with a closing surface which, when the adjustable upper boost pressure is reached, for leak-free closure of the connection between the control connection and the outlet forming a leak, a sealing seat with a forms a fixed seat, which is arranged in a travel space of the closing piston, there is no backflow of pressure oil from the "loaded" respective hydraulic accumulator, especially during the downtime of the hydraulic system, to the tank.
  • the accumulator charging valve according to the invention also fulfills all requirements for safe operation of the connected hydraulic system.
  • the separating device is formed from the first pilot valve and the shut-off valve located between the inlet and the control connection, which, when the adjustable upper boost pressure is reached, forms the leakage connection between the control connection and seal the drain tightly.
  • control piston which interacts with the closing piston, forms a pressure compensator with the latter. This enables safe switching of the accumulator charging valve, regardless of the prevailing volume flows and viscosities.
  • the closing piston with its active surface facing and facing away from the control piston can be exposed to the pressure prevailing in the inlet or in the control connection and has on its active surface facing the control piston the closing part which can be brought into contact with the fixed one Part that is arranged between the inlet and the control connection in the travel space of the closing piston.
  • This provides a defined sealing point, by means of which a leak-oil-free seal between the control connection and the drain is ensured when the adjustable upper boost pressure is reached.
  • at least the control piston can be completely decoupled from the actual storage circuit of the hydraulic system.
  • the separating device with its respective sealing part is formed from the first pilot valve and the shut-off valve located between the inlet and the control connection.
  • this type of accumulator charging valve has a passage on the control piston which opens into the control chamber and which can be connected to a drain line, it can be reached, in particular when the system is at a standstill or from parts of the system to always charge the respective hydraulic accumulator to the upper boost pressure when it is put back into operation, even if the actually prevailing accumulator pressure is greater than the predeterminable lower boost pressure.
  • a defined charge state is always produced in the hydraulic accumulator, which corresponds to the upper charge pressure, so that the full accumulator capacity is then available for the hydraulic system.
  • the memory charging valve according to the invention is explained in more detail below with reference to two exemplary embodiments according to FIGS. 1 and 2.
  • the first embodiment of the accumulator charging valve according to the invention according to FIG. 1 is connected via the control connection B to a hydraulic system 10, of which only the hydraulic accumulator 12 is shown schematically in FIG. 1 and the feed line that leads away from the branch point 14 is shown schematically.
  • control connection B which partly leads into the valve body 16 of the accumulator charging valve, it also has an outlet T, which leads to a tank, and an inlet P, which is more common to a hydraulic pump 18 that can be driven by a motor M and therefore not described in detail Type is connected.
  • pilot valves 22 and 24 are placed on the valve body 16, the pilot valve 22 performing a pressure closing function and the pilot valve 24 performing a pressure limiting function. With these two pilot valves 22 and 24, the lower or upper boost pressure or switching point in the hydraulic system 10 can therefore be set. The respective setting is done via an adjustable control spring 26, which is guided in the valve body of the respective pilot valve 22, 24.
  • the structure and the mode of operation of such pilot valves 22, 24 are generally known to those skilled in the art and are therefore not described again in detail.
  • the rear valve spaces 28 and 30 of the two pilot valves 22 and 24 are connected to one another via a transverse bore 32.
  • a leakage oil line L shown broken off, branches off from this transverse bore 32 and opens into a leakage oil collection point.
  • This leakage oil line L has at least at the end in the area of the leakage oil collection point essentially the atmospheric pressure, which facilitates the drainage of the leakage oil.
  • the leak oil line L can also be connected to the outlet T, which opens into the tank and which can accordingly have a higher pressure than the atmospheric pressure.
  • the two front valve spaces 34 and 36 of the two pilot valves 22 and 24 also communicate with one another via a cross connection 38 in the form of a bore.
  • a control piston 42 is arranged in a longitudinally displaceable manner in a piston chamber 40 extending transversely in the valve body 16.
  • the inlet P and the outlet T open into this piston chamber 40.
  • the interior of the control piston 42 together with the wall of the piston chamber 40, encloses a control chamber 44, in which a piston spring 46 is arranged, which cooperates with a valve ball 48 and is designated as a whole by 50 Check valve forms.
  • the check valve 50 when actuated by the pressure in the inlet P, serves to establish a connection between the inlet P and the control chamber 44, which has a branch 52 at the end, which opens into the front valve chamber 36 of the second pilot valve 24.
  • the piston chamber 40 is closed at its open-ended end by means of a hexagon screw 54 and opens with its other opposite end into a travel space 56 of comparable size.
  • a hexagon screw 54 instead of the valve ball 48, another correspondingly suitable closing element can be used, for example in the form of a conical or plate-shaped component or the like.
  • a displaceable piston 58 is arranged displaceably in this travel space 56 and, as part of the separating device according to the invention, cooperates with the control piston 42 and forms a pressure compensator with the latter.
  • the locking piston 58 which essentially consists of a steel material, has circumferential grooves 60 distributed along its circumference at predeterminable distances from one another, which act like lubrication grooves and permit a smooth movement of the locking piston 58.
  • the closing piston 58 In its position shown in FIG. 1, the closing piston 58 abuts with its one end on an end screw 62 which closes off the travel space 56 from the outside.
  • the closing piston 58 has a cylindrical connecting piece 64 which is connected in one piece to the closing piston 58 and which carries a web 66 at its end facing the control piston 42.
  • This web 66 engages over the through bore 68 arranged in the control piston 42, which creates the connection between the control chamber 44 and the inlet P and which, according to the basic position of the check valve 50 shown in FIG. 1, is closed by its valve ball 48.
  • the two free, opposite ends of the web 66 rest on the end face of the control piston 42, two opening regions of the bore 68 then separated from the web 66 being constantly connected to the inlet P.
  • the separating device in the closing piston 58 has a closing part in the form of a conically shaped closing surface 72 on its active surface 70 facing the control piston 42, which is seen to the left when the closing piston 58 is moved in FIG. 1 Can be brought into contact with a fixed part in the form of a conical seat surface 74 adapted to the closing surface 72, which is arranged in the travel space 56 and delimits it at the end.
  • the sealing part of the separating device therefore consists of the movable closing part in the form of the closing surface 72 and the seat surface 74 designed as a fixed part, both of which can be brought into sealing contact with one another.
  • the active surface 76 of the closing piston 58 facing away from the control piston 42 delimits a part 78 of the travel space 56 which is somewhat enlarged in diameter and into which a branch 80 lying between the check valve in the form of the check valve 20 and the control connection B and a connecting line 82 which leads to the first Pilot valve 22 leads.
  • the accumulator loading valve also has two further sealing parts in the two valve tappets 84 and 86 of the two pilot valves 22 and 24, which each have a conical closing surface 88 at the end, which has a fixed part in the form of a Seat edge 90 interact, which is part of the valve housing of the two pilot valves 22 and 24.
  • the valve lifter 84 of the first pilot valve 22 can open or block the path between the connecting line 82 to the front valve chamber 34.
  • the valve lifter 86 of the second pilot valve 24 establishes or separates the connection between the front valve chamber 36 and the rear valve chamber 30.
  • the hydraulic pump 18 drives pressure medium via the inlet P and the check valve 20, which then opens accordingly, pressure medium into the accumulator circuit and thus into the hydraulic system 10, in this case the control piston 42 and the closing piston 58 largely pressure-equalized and are held by the piston spring 46 in their position shown in FIG.
  • the inlet P is separated from the outlet T and the first pilot valve 22 is opened, whereas the second pilot valve 24 is closed.
  • a connection between the control connection B and the cross connection 38 is thus established via the first pilot valve 22, whereas the connection between the branch 52 and the cross bore 32 is prevented via the second pilot valve 24.
  • the first pilot valve 22 at the seat edge 90 closes first.
  • the pressure in the inlet P opens the check valve 50 and fluid, the second, flows through the bore 68, the control chamber 44 and the branch 52 Pilot valve 24 opens at the location of its seat edge 90.
  • the control chamber 44 of the control piston 42 is therefore limited by means of the second pilot valve 24 to its predeterminable pressure, which here differs from the value zero, which then drops when the second pilot valve 24 is actuated, the two-part pressure compensator formed from the control piston 42 and the closing piston 58 is no longer pressure equalized, so that the closing piston 58 moves the control piston 42 in FIG. 1 as seen under the influence of the upper boost pressure prevailing in the control connection B against the action of the piston spring 46 via the connecting piece 64 and the web 66. In this switching position assumed on the left, the closing piston 58 presses with its closing surface 72 against the seat surface 74 of the travel space 56 and thus seals the connection between the control connection B and the outlet T without leakage.
  • the control piston 42 itself releases the connection between inlet P and outlet T and the check valve 20 closes, so that the hydraulic accumulator 12 of the hydraulic system 10 is permanently charged to the upper boost pressure and the hydraulic pump 18 delivers hydraulic oil from inlet P immediately after a slight pressure difference Expiration T.
  • the piston spring 46 thus pushes the control piston 42 and thus the closing piston 58 back into the basic position shown in FIG. 1 when the adjustable boost pressure has fallen below its lower limit value, the control piston 42 again separating the inlet P from the outlet T and the charging cycle again from inlet P to control connection 3.
  • the control piston 42 and the closing piston 58 have approximately the same size ratios, in particular their outer diameter is the same. Furthermore, their longitudinal axes lie essentially on a common line.
  • the seat diameter formed by the seat surface 74 in the travel space 56 is smaller than the piston outer diameter of the closing piston 58 measured at the point where it is in contact with the travel space 56. This results in the described downshifting process in addition to the force of the piston spring 46, a force component that results from the specified diameter difference and the prevailing downshifting pressure that the release of the closing surface 72 from the seat surface 74 and thus the movement of the closing piston 58 in Fig.1 seen relieved to the right. As soon as the seat surface 72 has detached from the seat surface 74, the surface area ratio no longer plays a role and the two pistons are in turn pressure-balanced.
  • the second exemplary embodiment of a store loading valve according to the invention is only explained to the extent that it differs significantly from the first described embodiment.
  • Components relating to the second exemplary embodiment, which correspond to the components of the first exemplary embodiment, are reproduced with the same reference numerals, however, increased by 100 in each case.
  • the closing piston 58 has been omitted and only the control piston 142 has been used.
  • the piston spring 146 which is arranged in the interior of the control chamber 144, has one end directly on the control piston 142 and the other end on the second pilot valve 124.
  • the piston chamber 140 is installed longitudinally in the accumulator charging valve and the branch 52 is omitted because the control chamber 144 opens directly into the front valve chamber 136 of the second pilot valve 124.
  • a continuous nozzle 152 Arranged in the control piston 142 at the end is a continuous nozzle 152 which forms a throttle point and which constantly connects the inlet P to the control chamber 144.
  • the piston spring 146 tries to hold the control piston 142 in its basic position shown in FIG.
  • an annular groove 194 designed as a lubrication groove which runs along the outer circumference of the control piston 142, is at least partially in register with the outlet T.
  • a further second annular groove 196 is in this way between the annular groove 194 and the end of the control piston 142 facing the second pilot valve 124 arranged on its outer circumference that in the basic position shown in FIG. 2, this circumferential annular groove 196 is completely covered by the valve wall of the valve body 116.
  • control piston 142 If the control piston 142 is moved from its basic position shown in FIG. 2 in FIG. 2 from bottom to top into its other end position, a connection between the control chamber 144 is established via a transverse bore 198 which is arranged in the bottom of the second annular groove 196 and a connecting line 102 running in the valve body 116, which leads into the upper transverse bore 132.
  • the control piston 142 Through the transverse bore 198 and the second annular groove 196, the control piston 142 thus has a passage which opens into the control chamber 144 and which can be connected to the leakage oil line L via the connecting line 102.
  • the separating device with its respective sealing part is formed from the first pilot valve 122 and the check valve located between the inlet P and the control connection B in the form of the check valve 120.
  • the pump 118 in turn delivers via the built-in check valve 120 into the storage circuit of the hydraulic system 110.
  • the control piston 142 is pressure-balanced and is in the basic position shown in FIG. 2 caused by the piston spring 146.
  • Inlet P is separated from outlet T and first pilot valve 122 is opened, whereas second pilot valve 124 is closed.
  • the pilot valve 122 closes first and when the upper boost pressure is reached, the second pilot valve 124 opens due to the pressure in the control chamber 144, which results from the fluid supply through the inlet P behind the nozzle 192.
  • the pressure prevailing in the leakage oil line L is then mainly present on the spring side of the control piston 142, since the oil which is constantly flowing in through the nozzle 192 can flow back to the largely unpressurized side via the passage 196, 198 mentioned.
  • the hydraulic system 110 is then charged to the upper boost pressure and the pump 118 delivers from inlet P to outlet T with little pressure loss.
  • the accumulator pressure prevailing in the hydraulic system 110 then acts on the check valve 120 and the first pilot valve 122 does not have any connection to the control piston 142 and thus to the outlet T due to their sealing effect allows the hydraulic system 110 to be completely leak-free shut-off at the lower and the upper boost pressure.
  • the pump 118 conveys from P to T with a low pressure drop.
  • the pressure in the hydraulic system drops due to oil extraction, but remains constant above the lower boost pressure.
  • the piston spring 146 pushes the control piston 142 back into its starting position due to the lack of oil delivery by the pump.
  • the pump 118 is switched on again, it pumps via the check valve 120 into the hydraulic accumulator 112, which is charged to the upper boost pressure.
  • the respectively movable closing part is formed from the rounded closing surface of a valve ball, which can be sealingly brought into contact with a fixed annular seat edge on the valve body.

Abstract

PCT No. PCT/EP92/00009 Sec. 371 Date Aug. 23, 1993 Sec. 102(e) Date Aug. 23, 1993 PCT Filed Jan. 1, 1992 PCT Pub. No. WO92/12350 PCT Pub. Date Jul. 23, 1992.The invention relates to an accumulator charging valve, which for the connection of an inlet P supplying a hydraulic system 10 to an outlet T when an adjustable upper charging pressure in the hydraulic system 10 is reached and for separating this connection when an adjustable lower charging pressure in the hydraulic system 10 is reached, is provided with a control piston 42, which in one of its two switching positions breaks the connection between the inlet P and outlet T and in the other switching position makes this connection. By means of a separating device, a control connection B connecting the hydraulic system 10 to the accumulator charging valve can be separated from the outlet T. On reaching the adjustable upper charging pressure, by means of at least one sealing part of the separating device, the connection forming a leakage point between the control connection B and the outlet T can be sealed hermetically. Due to this arrangement, inside the valve, in the range between the lower and the upper charging pressure, the hydraulic system 10 can be shut off in a completely non-leaking manner.

Description

Leckölfreies SpeicherladeventilLeak-free accumulator charging valve

Die Erfindung betrifft ein Speicherladeventil, das zum Verbinden eines ein Hydrauliksystem speisenden Zulaufs mit einem Ablauf bei Erreichen eines einstellbaren oberen Ladedruckes in dem Hydrauliksystem und zum Trennen dieser Verbindung bei Erreichen eines einstellbaren unteren Ladedruckes in dem Hydrauliksystem mit einem Steuerkolben versehen ist, der in einer seiner beiden Schaltstellungen die Verbindung zwischen Zulauf und Ablauf trennt und in der anderen Schaltstellung diese Verbindung herstellt, wobei mittels einer Trennvorrichtung ein das Hydrauliksystem mit dem Speicherladeventil verbindender Steueranschluß vom Ablauf getrennt und zum Einstellen des unteren und des oberen Ladedruckes ein erstes bzw. ein zweites Vorsteuerventil vorgesehen ist.The invention relates to an accumulator charging valve which is provided with a control piston for connecting an inlet feeding a hydraulic system to an outlet when an adjustable upper boost pressure is reached in the hydraulic system and for disconnecting this connection when an adjustable lower boost pressure is reached in the hydraulic system two switching positions separates the connection between inlet and outlet and in the other switching position establishes this connection, whereby a control connection connecting the hydraulic system with the accumulator charging valve is separated from the outlet by means of a separating device and a first and a second pilot valve are provided for setting the lower and the upper boost pressure is.

Dahingehende Speicherladeventile, die auch als Abschaltventile bezeichnet werden, werden üblicherweise bei Hydrauliksystemen bzw. Hydrokreisläufen eingesetzt, die mindestens einen Hydrospeicher zur Konstanthaltung des Druckes im Hydrauliksystem aufweisen. Der jeweilige Hydrospeicher arbeitet hierbei in einem Bereich zwischen einem unteren und einem oberen Ladedruck, dessen jeweilige Druckhöhe einstellbar, mithin also frei wählbar ist. Wird der untere oder der obere Ladedruck unterschritten bzw. überschritten, wird mittels des Speicherladeventils die Verbindung zum die Druckölversorgung sicherstellenden Zulauf hergestellt bzw. getrennt. Die mithin einstellbare Differenz zwischen dem unteren und dem oberen Ladedruck kann groß sein aber auch sehr kleine Werte annehmen.Accumulating store loading valves, which are also referred to as shutdown valves, are usually used in Hydraulic systems or hydraulic circuits are used which have at least one hydraulic accumulator for keeping the pressure in the hydraulic system constant. The respective hydraulic accumulator works in a range between a lower and an upper boost pressure, the respective pressure level of which can be adjusted, and is therefore freely selectable. If the charge pressure falls below or exceeds the lower or the upper charge pressure, the connection to the inlet ensuring the pressure oil supply is established or separated by means of the accumulator charge valve. The adjustable difference between the lower and the upper boost pressure can be large but can also take very small values.

Ein dahingehend gattungsgleiches Speicherladeventil ist bereits in der DE-PS 36 08 100 beschrieben worden. Bei diesem bekannten Speicherladeventil soll eine möglichst geringe Leckrate innerhalb des Ventils erreicht werden, um zu gewährleisten, daß der jeweilige Hydrospeicher auch über längere Zeit hinweg den eingestellten Systemdruck hält. Dieses bekannte Speicherladeventil weist einen Steuerkolben auf, wobei der eine Kolbenteil als Trennvorrichtung ausgebildet in jeder einnehmbaren Schaltstellung des Steuerkolbens die Verbindung zwischen Steueranschluß und Ablauf trennt, der in den Tank mündet. Über einen durch diesen Kolbenteil gebildeten Ringspalt kommt es zur Leckage zwischen dem Steueranschluß und dem zum Tank führenden Ablauf. Dadurch verringert sich der Ladedruck im Speicher, was die in der DE-PS 36 08 100 beschriebenen Nachteile mit sich bringt.A storage charging valve of the same type has already been described in DE-PS 36 08 100. In this known accumulator charging valve, the lowest possible leakage rate within the valve is to be achieved in order to ensure that the respective hydraulic accumulator maintains the set system pressure even over a long period of time. This known accumulator charging valve has a control piston, the one piston part being designed as a separating device in each ingestible switching position of the control piston separating the connection between the control connection and the outlet which opens into the tank. Leakage occurs between the control connection and the outlet leading to the tank via an annular gap formed by this piston part. This reduces the boost pressure in the accumulator, which has the disadvantages described in DE-PS 36 08 100.

Durch die DE-OS 37 44 178 ist eine gattungsfremde Ausführungsform eines hydraulischen Speicherladeventiles bekannt, das einen Hauptkolben aufweist sowie eine über eine Drosselstelle mit Druckmittel vom Zulauf versorgten Vorsteuerung, mit einem als Sitzventil ausgeführten Vorsteuerventil, das nach dem beim Abschaltoruck erreichten Öffnen durch einen Entsperrkolben in Öffenstellung gehalten wird und so die Abschaltstellung des Hauptkolbens herbeiführt und diese bis zum Erreichen eines niedrigeren Zuschaltdruckes sichert. Dank dieser Ausbildung tritt zumindest bei belastetem Ablauf kein Steuerölverlust mehr auf. Hierzu wird ein Rückströmen des Fluids aus einem an das Speicherladeventil angeschlossenen Hydrospeicher durch ein geschlossenes Rückschlagventil verhindert, das in dem Hauptkolben angeordnet ist, der eine abgesetzte Ringfläche aufweist, die unter Bildung eines dicht schließenden Sitzventiles mit einer innerhalb des Gehäuses angeordneten Stufe in Anlage bringbar ist. Hierdurch läßt sich der Inhalt des Hydrospeichers leckagefrei abschließen.From DE-OS 37 44 178 a non-generic embodiment of a hydraulic accumulator charging valve is known, which has a main piston and a pilot control supplied with pressure medium from the inlet via a throttle point, with a pilot valve designed as a seat valve, which, after opening when the shutdown is reached, is released by an unlocking piston is held in the open position and so brings about the switch-off position of the main piston and this until it is reached of a lower cut-in pressure. Thanks to this training, there is no longer any loss of control oil, at least when the process is stressed. For this purpose, backflow of the fluid from a hydraulic accumulator connected to the accumulator charging valve is prevented by a closed non-return valve which is arranged in the main piston and which has a stepped annular surface which can be brought into contact with a step arranged inside the housing, forming a tightly closing seat valve . As a result, the contents of the hydraulic accumulator can be closed without leakage.

Ausgehend von diesen Stand der Technik liegt der Erfindung die Aufgabe zugrunde, ein Speicherladeventil mit frei einstellbaren Schaltpunkten zu schaffen, das mit Sicherheit derart leckölfrei arbeitet, daß der Druck im Hydrospeicher auch über einen längeren Zeitraum hinweg konstant gehalten ist.Based on this prior art, the invention has for its object to provide a accumulator charging valve with freely adjustable switching points, which works with such a leak-free oil that the pressure in the hydraulic accumulator is kept constant even over a longer period of time.

Diese Aufgabe löst ein Speicherladeventil mit den Merkmalen des Anspruches 1 oder des Anspruches 2.This object is achieved by a storage charging valve with the features of claim 1 or claim 2.

Dadurch, daß bei dem erfindungsgemäßen Speicherladeventil mit den Merkmalen des Oberbegriffes des Anspruches 1 die Trennvorrichtung einen Schließkolben mit einer Schließfläche aufweist, die bei Erreichen des einstellbaren oberen Ladedruckes zum leckölfreien Abschluß der eine Leckstelle bildenden Verbindung zwischen dem Steueranschluß und dem Ablauf einen dichtenden Sitz mit einer feststehenden Sitzfläche bildet, die in einem Verfahrraum des Schließkolbens angeordnet ist, findet kein Rückfluß von Drucköl vom "geladenen" jeweiligen Hydrospeicher, insbesondere während der Stillstandszeiten des Hydrauliksystems, zum Tank hin statt. Damit erfüllt das erfindungsgemäße Speicherladeventil aber auch alle Anforderungen an einen sicheren Betrieb des angeschlossenen Hydrauliksystems.Characterized in that in the accumulator charging valve according to the invention with the features of the preamble of claim 1, the separating device has a closing piston with a closing surface which, when the adjustable upper boost pressure is reached, for leak-free closure of the connection between the control connection and the outlet forming a leak, a sealing seat with a forms a fixed seat, which is arranged in a travel space of the closing piston, there is no backflow of pressure oil from the "loaded" respective hydraulic accumulator, especially during the downtime of the hydraulic system, to the tank. However, the accumulator charging valve according to the invention also fulfills all requirements for safe operation of the connected hydraulic system.

Dasselbe gilt, wenn bei der anderen erfindungsgemäßen Lösung gemäß den Merkmalen des Anspruches 2 die Trennvorrichtung aus dem ersten Vorsteuerventil und dem zwischen dem Zulauf und dem Steueranschluß liegenden Sperrventil gebildet ist, die bei Erreichen des einstellbaren oberen Ladedruckes die eine Leckstelle bildende Verbindung zwischen dem Steueranschluß und dem Ablauf dichtend verschließen.The same applies if, in the other solution according to the invention, the separating device is formed from the first pilot valve and the shut-off valve located between the inlet and the control connection, which, when the adjustable upper boost pressure is reached, forms the leakage connection between the control connection and seal the drain tightly.

Weitere vorteilhafte Ausgestaltungen des erfindungsgemäßen Speicherladeventils sind Gegenstand der Unteransprüche.Further advantageous refinements of the accumulator charging valve according to the invention are the subject of the subclaims.

Bei einer bevorzugten Ausführungsform des erfindungsgemäßen Speicherladeventils bildet der Steuerkolben, der mit dem Schließkolben zusammenwirkt, mit diesem eine Druckwaage aus. Dies erlaubt ein sicheres Schalten des Speicherladeventils, unabhängig von den herrschenden Volumenströmen und Viskositäten.In a preferred embodiment of the accumulator loading valve according to the invention, the control piston, which interacts with the closing piston, forms a pressure compensator with the latter. This enables safe switching of the accumulator charging valve, regardless of the prevailing volume flows and viscosities.

Bei einer weiteren bevorzugten Ausführungsform des erfindungsgemäßen Speicherladeventils ist der Schließkolben mit seiner dem Steuerkolben zu- und abgewandten Wirkfläche dem im Zulauf bzw. im Steueranschluß herrschenden Druck aussetzbar und weist an seiner dem Steuerkolben zugewandten Wirkfläche das Schließteil auf, das in Anlage bringbar ist mit dem feststehenden Teil, das zwischen Zulauf und Steueranschluß im Verfahrraum des Schließkolbens angeordnet ist. Hierdurch ist eine definierte Dichtstelle gegeben, mittels der eine leckölfreie Abdichtung zwischen dem Steueranschluß und dem Ablauf bei Erreichen des einstellbaren oberen Ladedruckes gewährleistet ist. Darüberhinaus läßt sich zumindest der Steuerkolben vollständig vom eigentlichen Speicherkreis des Hydrauliksystems entkoppeln.In a further preferred embodiment of the accumulator loading valve according to the invention, the closing piston with its active surface facing and facing away from the control piston can be exposed to the pressure prevailing in the inlet or in the control connection and has on its active surface facing the control piston the closing part which can be brought into contact with the fixed one Part that is arranged between the inlet and the control connection in the travel space of the closing piston. This provides a defined sealing point, by means of which a leak-oil-free seal between the control connection and the drain is ensured when the adjustable upper boost pressure is reached. In addition, at least the control piston can be completely decoupled from the actual storage circuit of the hydraulic system.

Bei einer anderen bevorzugten Art des erfindungsgemäßen Speicherladeventils ist bei Erreichen des oberen Ladedruckes die Trennvorrichtung mit ihrem jeweiligen Dichtteil aus dem ersten Vorsteuerventil und dem zwischen dem Zulauf und dem Steueranschluß liegenden Sperrventil gebildet. Auch bei dieser Lösung ist ein sicheres und leckölfreies Abdichten gewährleistet.In another preferred type of accumulator charging valve according to the invention, when the upper boost pressure is reached, the separating device with its respective sealing part is formed from the first pilot valve and the shut-off valve located between the inlet and the control connection. This solution also guarantees a secure and leak-oil-free seal.

Sofern diese Art des erfindungsgemäßen Speicherladeventils am Steuerkolben einen Durchgang aufweist, der in den Steuerraum mündet und der mit einer Leckölleitung verbindbar ist, ist es erreichbar, insbesondere bei Stillstand der Anlage oder von Teilen der Anlage, den jeweiligen Hydrospeicher bei der Wiederinbetriebnahme immer auf den oberen Ladedruck hin aufzuladen, auch wenn der tatsächlich herrschende Speicherdruck größer ist als der vorgebbare untere Ladedruck. Somit wird gegenüber den bekannten Speicherladeventilen, bei denen das erneute Laden grundsätzlich erst nach Unterschreiten des unteren Ladedruckes erfolgt, im Hydrospeicher immer ein definierter Ladezustand hergestellt, der dem oberen Ladedruck entspricht, so daß für das Hydrauliksystem dann die volle Speicherkapazität zur Verfügung steht.If this type of accumulator charging valve according to the invention has a passage on the control piston which opens into the control chamber and which can be connected to a drain line, it can be reached, in particular when the system is at a standstill or from parts of the system to always charge the respective hydraulic accumulator to the upper boost pressure when it is put back into operation, even if the actually prevailing accumulator pressure is greater than the predeterminable lower boost pressure. Thus, compared to the known accumulator charging valves, in which recharging generally only takes place after the lower charge pressure has been undershot, a defined charge state is always produced in the hydraulic accumulator, which corresponds to the upper charge pressure, so that the full accumulator capacity is then available for the hydraulic system.

Im folgenden ist das erfindungsgemäße Speicherladeventil anhand zweier Ausführungsbeispiele gemäß den Fig.1 und 2 näher erläutert.The memory charging valve according to the invention is explained in more detail below with reference to two exemplary embodiments according to FIGS. 1 and 2.

Das erste Ausführungsbeispiel des erfindungsgemäßen Speicherladeventils gemäß Fig.1 ist über den Steueranschluß B an ein Hydrauliksystem 10 angeschlossen, von dem zur Vereinfachung in der Fig.1 nur der Hydrospeicher 12 schematisch und die Zuleitung dargestellt sind, die von dem Abzweigpunkt 14 wegführt.The first embodiment of the accumulator charging valve according to the invention according to FIG. 1 is connected via the control connection B to a hydraulic system 10, of which only the hydraulic accumulator 12 is shown schematically in FIG. 1 and the feed line that leads away from the branch point 14 is shown schematically.

Neben dem Steueranschluß B, der teilweise in den Ventilkörper 16 des Speicherladeventils führt, weist dieser noch einen Ablauf T auf, der zu einem Tank führt, sowie einen Zulauf P, der an eine über einen Motor M antreibbare Hydraulikpumpe 18 üblicher und daher nicht näher beschriebener Bauart angeschlossen ist. Zwischen dem Zulauf P und dem Steueranschluß B ist ein in Richtung Zulauf P schließendes Sperrventil in Form eines Rückschlagventils 20 geschaltet.In addition to the control connection B, which partly leads into the valve body 16 of the accumulator charging valve, it also has an outlet T, which leads to a tank, and an inlet P, which is more common to a hydraulic pump 18 that can be driven by a motor M and therefore not described in detail Type is connected. A shut-off valve in the form of a check valve 20, which closes in the direction of the inlet P, is connected between the inlet P and the control connection B.

Auf den Ventilkörper 16 sind zwei Vorsteuerventile 22 und 24 aufgesetzt, wobei das Vorsteuerventil 22 eine Druckschließfunktion wahrnimmt und das Vorsteuerventil 24 eine Druckbegrenzungsfunktion. Mit diesen beiden Vorsteuerventilen 22 und 24 läßt sich mithin der untere bzw. obere Ladedruck oder Schaltpunkt in dem Hydrauliksystem 10 einstellen. Das diesbezügliche Einstellen geschieht jeweils über eine verstellbare Regelfeder 26, die in dem Ventilkörper des jeweiligen Vorsteuerventils 22,24 geführt ist. Der Aufbau und die Wirkungsweise dahingehender Vorsteuerventile 22,24 sind der Fachwelt allgemein bekannt und werden daher nicht noch einmal näher beschrieben.Two pilot valves 22 and 24 are placed on the valve body 16, the pilot valve 22 performing a pressure closing function and the pilot valve 24 performing a pressure limiting function. With these two pilot valves 22 and 24, the lower or upper boost pressure or switching point in the hydraulic system 10 can therefore be set. The respective setting is done via an adjustable control spring 26, which is guided in the valve body of the respective pilot valve 22, 24. The structure and the mode of operation of such pilot valves 22, 24 are generally known to those skilled in the art and are therefore not described again in detail.

Die hinteren Ventilräume 28 und 30 der beiden Vorsteuerventile 22 bzw. 24 sind über eine Querbohrung 32 miteinander verbunden. Von dieser Querbohrung 32 zweigt eine abgebrochen dargestellte Leckölleitung L ab, die in eine Leckölsammelstelle mündet. Diese Leckölleitung L weist zumindest endseitig im Bereich der Leckölsammelstelle im wesentlichen den atmosphärischen Druck auf, was das Abfließen des Lecköls erleichtert. Die Leckölleitung L kann aber auch an den Ablauf T angeschlossen sein, der in den Tank mündet und der demgemäß einen höheren Druck aufweisen kann als der atmosphärische Druck. Die beiden vorderen Ventilräume 34 und 36 der beiden Vorsteuerventile 22 bzw. 24 kommunizieren ebenfalls miteinander über eine Querverbindung 38 in Form einer Bohrung.The rear valve spaces 28 and 30 of the two pilot valves 22 and 24 are connected to one another via a transverse bore 32. A leakage oil line L, shown broken off, branches off from this transverse bore 32 and opens into a leakage oil collection point. This leakage oil line L has at least at the end in the area of the leakage oil collection point essentially the atmospheric pressure, which facilitates the drainage of the leakage oil. The leak oil line L can also be connected to the outlet T, which opens into the tank and which can accordingly have a higher pressure than the atmospheric pressure. The two front valve spaces 34 and 36 of the two pilot valves 22 and 24 also communicate with one another via a cross connection 38 in the form of a bore.

In einem im Ventilkörper 16 quer verlaufenden Kolbenraum 40 ist längsverschiebbar ein Steuerkolben 42 angeordnet. In diesen Kolbenraum 40 münden der Zulauf P sowie der Ablauf T. Das Innere des Steuerkolbens 42 umschließt zusammen mit der Wand des Kolbenraumes 40 einen Steuerraum 44, in dem eine Kolbenfeder 46 angeordnet ist, die mit einer Ventilkugel 48 zusammenwirkend ein als Ganzes mit 50 bezeichnetes Rückschlagventil bildet. Das Rückschlagventil 50 dient in seinem über den Druck im Zulauf P betätigten Zustand zum Herstellen einer Verbindung zwischen Zulauf P und dem Steuerraum 44, der endseitig eine Abzweigung 52 aufweist, die in den vorderen Ventilraum 36 des zweiten Vorsteuerventils 24 mündet. Der Kolbenraum 40 ist an seinem ins Freie mündenden Ende mittels einer Sechskantschraube 54 verschlossen und mündet mit seinem anderen gegenüberliegenden Ende in einen der Größe nach vergleichbar aufgebauten Verfahrraum 56. Anstelle der Ventilkugel 48 kann auch ein anderes entsprechend geeignetes Schließelement verwendet werden, beispielsweise in Form eines kegeloder plattenförmigen Bauteils oder dergleichen.A control piston 42 is arranged in a longitudinally displaceable manner in a piston chamber 40 extending transversely in the valve body 16. The inlet P and the outlet T open into this piston chamber 40. The interior of the control piston 42, together with the wall of the piston chamber 40, encloses a control chamber 44, in which a piston spring 46 is arranged, which cooperates with a valve ball 48 and is designated as a whole by 50 Check valve forms. The check valve 50, when actuated by the pressure in the inlet P, serves to establish a connection between the inlet P and the control chamber 44, which has a branch 52 at the end, which opens into the front valve chamber 36 of the second pilot valve 24. The piston chamber 40 is closed at its open-ended end by means of a hexagon screw 54 and opens with its other opposite end into a travel space 56 of comparable size. Instead of the valve ball 48, another correspondingly suitable closing element can be used, for example in the form of a conical or plate-shaped component or the like.

In diesem Verfahrraum 56 verschiebbar angeordnet ist ein Schließkolben 58, der als Teil der erfindungsgemäßen Trennvorrichtung mit dem Steuerkolben 42 zusammenwirkt und mit diesem eine Druckwaage bildet. Der im wesentlichen aus einem Stahlwerkstoff bestehende Schließkolben 58 weist entlang seines Umfanges in vorgebbaren Abständen voneinander verteilt Umlaufrillen 60 auf, die wie Schmiernuten wirken und eine störungslose Verfahrbewegung des Schließkolbens 58 erlauben. In seiner in der Fig.1 dargestellten Stellung stößt der Schließkolben 58 mit seinem einen Ende an eine Abschlußschraube 62, die den Verfahrraum 56 nach außen hin abschließt. An seinem anderen, der Abschlußschraube 62 abgekehrten Ende weist der Schließkolben 58 einen zylindrischen Stutzen 64 auf, der mit dem Schließkolben 58 einstückig verbunden ist und der an seinem dem Steuerkolben 42 zugekehrten Ende einen Steg 66 trägt. Dieser Steg 66 übergreift die im Steuerkolben 42 angeordnete durchgehende Bohrung 68, die die Verbindung zwischen dem Steuerraum 44 und dem Zulauf P herstellt und die gemäß der in Fig.1 dargestellten Grundstellung des Rückschlagventils 50 von dessen Ventilkugel 48 verschlossen ist. Hierbei liegen die beiden freien, einander gegenüberliegenden Enden des Steges 66 auf der endseitigen Fläche des Steuerkolbens 42 auf, wobei zwei von dem Steg 66 dann getrennte Öffnungsbereiche der Bohrung 68 ständig in Verbindung mit dem Zulauf P stehen.A displaceable piston 58 is arranged displaceably in this travel space 56 and, as part of the separating device according to the invention, cooperates with the control piston 42 and forms a pressure compensator with the latter. The locking piston 58, which essentially consists of a steel material, has circumferential grooves 60 distributed along its circumference at predeterminable distances from one another, which act like lubrication grooves and permit a smooth movement of the locking piston 58. In its position shown in FIG. 1, the closing piston 58 abuts with its one end on an end screw 62 which closes off the travel space 56 from the outside. At its other end facing away from the end screw 62, the closing piston 58 has a cylindrical connecting piece 64 which is connected in one piece to the closing piston 58 and which carries a web 66 at its end facing the control piston 42. This web 66 engages over the through bore 68 arranged in the control piston 42, which creates the connection between the control chamber 44 and the inlet P and which, according to the basic position of the check valve 50 shown in FIG. 1, is closed by its valve ball 48. Here, the two free, opposite ends of the web 66 rest on the end face of the control piston 42, two opening regions of the bore 68 then separated from the web 66 being constantly connected to the inlet P.

Zum dichtenden Verschließen der Verbindung zwischen Steueranschluß B und Ablauf T weist die Trennvorrichtung bei dem Schließkolben 58 an seiner dem Steuerkolben 42 zugewandten Wirkfläche 70 ein Schließteil in Form einer konisch ausgebildeten Schließfläche 72 auf, die bei Verschieben des Schließkolbens 58 in Fig.1 gesehen nach links in Anlage bringbar ist mit einem feststehenden Teil in Form einer der Schließfläche 72 angepaßten konischen Sitzfläche 74, die im Verfahrraum 56 angeordnet ist und diesen endseitig begrenzt. Das Dichtteil der Trennvorrichtung besteht also im vorliegenden Ausführungsbeispiel aus dem verfahrbaren Schließteil in Form der Schließfläche 72 und der als feststehendes Teil ausgebildeten Sitzfläche 74, die beide dichtend miteinander in Anlage bringbar sind. Die dem Steuerkolben 42 abgewandte Wirkfläche 76 des Schließkolbens 58 begrenzt einen im Durchmesser etwas erweiterten Teil 78 des Verfahrraumes 56, in den eine zwischen dem Sperrventil in Form des Rückschlagventils 20 und dem Steueranschluß B liegende Abzweigung 80 sowie eine Verbindungsleitung 82 mündet, die zu dem ersten Vorsteuerventil 22 führt.To seal the connection between the control connection B and the outlet T, the separating device in the closing piston 58 has a closing part in the form of a conically shaped closing surface 72 on its active surface 70 facing the control piston 42, which is seen to the left when the closing piston 58 is moved in FIG. 1 Can be brought into contact with a fixed part in the form of a conical seat surface 74 adapted to the closing surface 72, which is arranged in the travel space 56 and delimits it at the end. In the present exemplary embodiment, the sealing part of the separating device therefore consists of the movable closing part in the form of the closing surface 72 and the seat surface 74 designed as a fixed part, both of which can be brought into sealing contact with one another. The active surface 76 of the closing piston 58 facing away from the control piston 42 delimits a part 78 of the travel space 56 which is somewhat enlarged in diameter and into which a branch 80 lying between the check valve in the form of the check valve 20 and the control connection B and a connecting line 82 which leads to the first Pilot valve 22 leads.

Neben dem angesprochenen Dichtteil bei dem Schließkolben 58 weist das erfindungsgemäße Speicherladeventil noch zwei weitere Dichtteile bei den beiden Ventilstößeln 84 und 86 der beiden Vorsteuerventile 22 bzw.24 auf, die endseitig jeweils über eine konische Schließfläche 88 verfügen, die mit einem feststehenden Teil in Form einer Sitzkante 90 zusammenwirken, die Teil des Ventilgehäuses der beiden Vorsteuerventile 22 und 24 ist. Hierbei kann der Ventilstößel 84 des ersten Vorsteuerventils 22 den Weg zwischen der Verbindungsleitung 82 zu dem vorderen Ventilraum 34 freigeben oder versperren. Der Ventilstößel 86 des zweiten Vorsteuerventils 24 hingegen stellt die Verbindung zwischen dem vorderen Ventilraum 36 und dem hinteren Ventilraum 30 her oder trennt diese voneinander.In addition to the mentioned sealing part in the closing piston 58, the accumulator loading valve according to the invention also has two further sealing parts in the two valve tappets 84 and 86 of the two pilot valves 22 and 24, which each have a conical closing surface 88 at the end, which has a fixed part in the form of a Seat edge 90 interact, which is part of the valve housing of the two pilot valves 22 and 24. Here, the valve lifter 84 of the first pilot valve 22 can open or block the path between the connecting line 82 to the front valve chamber 34. The valve lifter 86 of the second pilot valve 24, on the other hand, establishes or separates the connection between the front valve chamber 36 and the rear valve chamber 30.

Zum besseren Verständnis des erfindungsgemäßen Speicherladeventils wird im folgenden anhand des ersten Ausführungsbeispieles seine Funktion näher beschrieben. Fördert bei der in der Fig.1 dargestellten Grundstellung des Speicherladeventils über den Motor M angetrieben die Hydraulikpumpe 18 Druckmittel über den Zulauf P und das Rückschlagventil 20, das dann demgemäß öffnet, Druckmittel in den Speicherkreis und damit in das Hydrauliksystem 10, sind hierbei der Steuerkolben 42 und der Schließkolben 58 weitgehend druckausgeglichen und werden über die Kolbenfeder 46 in ihrer in der Fig.1 gezeigten Stellung gehalten. Wie dies die Fig.1 deutlich macht, ist hierbei der Zulauf P vom Ablauf T getrennt und das erste Vorsteuerventil 22 geöffnet, wohingegen das zweite Vorsteuerventil 24 geschlossen ist. Es ist also über das erste Vorsteuerventil 22 eine Verbindung zwischen dem Steueranschluß B und der Querverbindung 38 hergestellt, wohingegen über das zweite Vorsteuerventil 24 die Verbindung zwischen Abzweigung 52 und Querbohrung 32 unterbunden ist.For a better understanding of the store loading valve according to the invention, its function is described in more detail below with reference to the first embodiment. In the basic position of the accumulator charging valve shown in FIG. 1 driven by the motor M, the hydraulic pump 18 drives pressure medium via the inlet P and the check valve 20, which then opens accordingly, pressure medium into the accumulator circuit and thus into the hydraulic system 10, in this case the control piston 42 and the closing piston 58 largely pressure-equalized and are held by the piston spring 46 in their position shown in FIG. As is clear from FIG. 1, the inlet P is separated from the outlet T and the first pilot valve 22 is opened, whereas the second pilot valve 24 is closed. A connection between the control connection B and the cross connection 38 is thus established via the first pilot valve 22, whereas the connection between the branch 52 and the cross bore 32 is prevented via the second pilot valve 24.

Durch den fortschreitenden Druckanstieg im Hydrauliksystem 10 und im Hydrospeicher 12 schließt zuerst das erste Vorsteuerventil 22 an der Sitzkante 90. Der Druck im Zulauf P öffnet das Rückschlagventil 50 und über die Bohrung 68, den Steuerraum 44 und die Abzweigung 52 fließt Fluid, das das zweite Vorsteuerventil 24 an der Stelle seiner Sitzkante 90 öffnet.Due to the progressive pressure increase in the hydraulic system 10 and in the hydraulic accumulator 12, the first pilot valve 22 at the seat edge 90 closes first. The pressure in the inlet P opens the check valve 50 and fluid, the second, flows through the bore 68, the control chamber 44 and the branch 52 Pilot valve 24 opens at the location of its seat edge 90.

Der Steuerraum 44 des Steuerkolbens 42 ist also mittels des zweiten Vorsteuerventils 24 auf seinem vorgebbaren Druck, der hier von dem Wert Null verschieden ist, begrenzt, der bei Betätigung des zweiten Vorsteuerventils 24 dann abfällt, wobei die zweiteilige Druckwaage gebildet aus Steuerkolben 42 und Schließkolben 58 nicht mehr druckausgeglichen ist, so daß der Schließkolben 58 über den Stutzen 64 und den Steg 66 den Steuerkolben 42 in Fig.1 gesehen unter dem Einfluß des im Steueranschluß B herrschenden oberen Ladedruckes entgegen der Wirkung der Kolbenfeder 46 nach links verschiebt. In dieser linksseitig eingenommenen Schaltstellung drückt der Schließkolben 58 mit seiner Schließfläche 72 gegen die Sitzfläche 74 des Verfahrraumes 56 und dichtet mithin leckagefrei die Verbindung zwischen dem Steueranschluß B und dem Ablauf T ab. Der Steuerkolben 42 selbst gibt hierbei die Verbindung zwischen Zulauf P und Ablauf T frei und das Rückschlagventil 20 schließt, so daß der Hydrospeicher 12 des Hydrauliksystems 10 auf den oberen Ladedruck bleibend geladen ist und die Hydraulikpumpe 18 fördert bei geringem Druckunterschied Hydrauliköl von Zulauf P unmittelbar nach Ablauf T.The control chamber 44 of the control piston 42 is therefore limited by means of the second pilot valve 24 to its predeterminable pressure, which here differs from the value zero, which then drops when the second pilot valve 24 is actuated, the two-part pressure compensator formed from the control piston 42 and the closing piston 58 is no longer pressure equalized, so that the closing piston 58 moves the control piston 42 in FIG. 1 as seen under the influence of the upper boost pressure prevailing in the control connection B against the action of the piston spring 46 via the connecting piece 64 and the web 66. In this switching position assumed on the left, the closing piston 58 presses with its closing surface 72 against the seat surface 74 of the travel space 56 and thus seals the connection between the control connection B and the outlet T without leakage. The control piston 42 itself releases the connection between inlet P and outlet T and the check valve 20 closes, so that the hydraulic accumulator 12 of the hydraulic system 10 is permanently charged to the upper boost pressure and the hydraulic pump 18 delivers hydraulic oil from inlet P immediately after a slight pressure difference Expiration T.

Im Gegensatz zum Stand der Technik ist also bei der hier eingenommenen Schaltstellung des erfindungsgemäßen Speicherladeventils eine vollständig leckölfreie Absperrung des Hydrauliksystems 10 erreicht. Kommt es zu einer Ölentnahme im Hydrauliksystem 10, kann der Druck auf der Lastdruckseite, also im Steueranschluß B, so lange abfallen, bis bei dem Vorsteuerventil 22 aufgrund der Federkraft der Regelfeder 26 über den Ventilstößel 84 die Schließfläche 88 sich von der Sitzkante 90 abhebt und damit dieses Ventil öffnet. Hierdurch gelangt von Steueranschluß B her Hydrauliköl in die Querverbindung 38 und über den vorderen Ventilraum 36 sowie die Abzweigung 52 auf die federbelastete Seite des Steuerkolbens 42.In contrast to the prior art, a completely leak-oil-free shut-off of the hydraulic system 10 is thus achieved in the switching position of the accumulator charging valve according to the invention assumed here. If there is an oil withdrawal in the hydraulic system 10, the pressure on the load pressure side, that is to say in the control connection B, can drop until the pilot valve 22, due to the spring force of the control spring 26 via the valve lifter 84, causes the closing surface 88 to lift off the seat edge 90 and so that this valve opens. As a result, hydraulic oil reaches control connection B into cross-connection 38 and via front valve chamber 36 and branch 52 onto the spring-loaded side of control piston 42.

Der im Steuerraum 44 dann herrschende Druck schließt das Rückschlagventil 50 und der Kolben 42 bewegt sich aufgrund der Druckausgeglichenheit zwischen der sogenannten Federraumseite und der Lastdruckseite in der Fig.1 gesehen nach rechts. Die Kolbenfeder 46 schiebt also den Steuerkolben 42 und damit den Schließkolben 58 in die in der Fig.1 gezeigte Grundstellung zurück, wenn der einstellbare Ladedruck seinen unteren Begrenzungswert unterschritten hat, wobei der Steuerkolben 42 wiederum den Zulauf P von Ablauf T trennt und der Ladezyklus erneut von Zulauf P nach Steueranschluß 3 erfolgt. Der Steuerkolben 42 und der Schließkolben 58 weisen in etwa dieselben Größenverhältnisse auf, insbesondere ist deren Außendurchmesser gleich. Ferner liegen deren Längsachsen im wesentlichen auf einer gemeinsamen Linie. Der durch die Sitzfläche 74 gebildete Sitzdurchnesser im Verfahrraum 56 ist kleiner als der Kolbenaußendurchmesser des Schließkolbens 58 gemessen an der Stelle, wo er in Anlage mit dem Verfahrraun 56 ist. Hierdurch ergibt sich beim beschriebenen Rückschaltvorgang zusätzlich zu der Kraft der Kolbenfeder 46 eine Kraftkomponente, die sich aus dem angegebenen Durchmesserunterschied und dem jeweils herrschenden Rückschaltdruck ergibt, die das Lösen der Schließfläche 72 von der Sitzfläche 74 und damit das Verfahren des Schließkolbens 58 in Fig.1 gesehen nach rechts erleichtert. Sobald sich die Sitzfläche 72 von der Sitzfläche 74 gelöst hat, spielt das angesprochene Flächenverhältnis keine Rolle mehr und die beiden Kolben sind wiederum druckausgeglichen.The pressure then prevailing in the control chamber 44 closes the check valve 50 and the piston 42 moves due to the pressure balance between the so-called spring chamber side and the load pressure side in FIG. 1 to the right. The piston spring 46 thus pushes the control piston 42 and thus the closing piston 58 back into the basic position shown in FIG. 1 when the adjustable boost pressure has fallen below its lower limit value, the control piston 42 again separating the inlet P from the outlet T and the charging cycle again from inlet P to control connection 3. The control piston 42 and the closing piston 58 have approximately the same size ratios, in particular their outer diameter is the same. Furthermore, their longitudinal axes lie essentially on a common line. The seat diameter formed by the seat surface 74 in the travel space 56 is smaller than the piston outer diameter of the closing piston 58 measured at the point where it is in contact with the travel space 56. This results in the described downshifting process in addition to the force of the piston spring 46, a force component that results from the specified diameter difference and the prevailing downshifting pressure that the release of the closing surface 72 from the seat surface 74 and thus the movement of the closing piston 58 in Fig.1 seen relieved to the right. As soon as the seat surface 72 has detached from the seat surface 74, the surface area ratio no longer plays a role and the two pistons are in turn pressure-balanced.

Das zweite Ausführungsbeispiel eines erfindungsgemäßen Speicherladeventils wird nur noch insoweit erläutert, als es sich von der zuerst beschriebenen Ausführungsform wesentlich unterscheidet. Hierbei werden das zweite Ausführungsbeispiel betreffende Bauteile, die den Bauteilen des ersten Ausführungsbeispiels entsprechen, mit derselben aber um jeweils 100 erhöhten Bezugsziffern wiedergegeben.The second exemplary embodiment of a store loading valve according to the invention is only explained to the extent that it differs significantly from the first described embodiment. Components relating to the second exemplary embodiment, which correspond to the components of the first exemplary embodiment, are reproduced with the same reference numerals, however, increased by 100 in each case.

Bei dem in Fig.2 gezeigten zweiten Ausführungsbeispiel ist der Schließkolben 58 entfallen und nur der Steuerkolben 142 verwendet. Die Kolbenfeder 146, die im Inneren des Steuerraumes 144 angeordnet ist, liegt mit ihren einen Ende unmittelbar an dem Steuerkolben 142 und mit ihrem anderen Ende an dem zweiten Vorsteuerventil 124 an. Der Kolbenraum 140 ist hier längs im Speicherladeventil eingebaut und die Abzweigung 52 ist entfallen, da der Steuerraum 144 unmittelbar in den vorderen Ventilraum 136 des zweiten Vorsteuerventils 124 mündet.In the second exemplary embodiment shown in FIG. 2, the closing piston 58 has been omitted and only the control piston 142 has been used. The piston spring 146, which is arranged in the interior of the control chamber 144, has one end directly on the control piston 142 and the other end on the second pilot valve 124. The piston chamber 140 is installed longitudinally in the accumulator charging valve and the branch 52 is omitted because the control chamber 144 opens directly into the front valve chamber 136 of the second pilot valve 124.

In dem Steuerkolben 142 ist endseitig eine eine Drosselstelle bildende durchgehende Düse 152 angeordnet, die ständig den Zulauf P mit dem Steuerraum 144 verbindet. Die Kolbenfeder 146 versucht den Steuerkolben 142 in seiner in der Fig.2 dargestellten Grundstellung zu halten. Hierbei ist eine als Schmiernut ausgebildete Ringnut 194, die entlang des Außenumfanges des Steuerkolbens 142 verläuft, zumindest teilweise in Deckung mit dem Ablauf T. Eine weitere zweite Ringnut 196 ist zwischen der Ringnut 194 und dem dem zweiten Vorsteuerventil 124 zugekehrten Ende des Steuerkolbens 142 derart entlang seines Außenumfanges angeordnet, daß in der in der Fig.2 dargestellten Grundstellung diese umlaufende Ringnut 196 von der Ventilwand des Ventilskörpers 116 vollständig abgedeckt ist. Wird der Steuerkolben 142 aus seiner in der Fig.2 dargestellten Grundstellung in Fig.2 gesehen von unten nach oben in seine andere Endstellung verfahren, wird über eine Querbohrung 198, die im Boden der zweiten Ringnut 196 angeordnet ist, eine Verbindung zwischen dem Steuerraum 144 und einer im Ventilkörper 116 verlaufenden Verbindungsleitung 102 hergestellt, die in die obere Querbohrung 132 mündet. Durch die Querbohrung 198 und die zweite Ringnut 196 weist der Steuerkolben 142 also einen Durchgang auf, der in den Steuerraum 144 mündet und der mit der Leckölleitung L über die Verbindungsleiung 102 verbindbar ist.Arranged in the control piston 142 at the end is a continuous nozzle 152 which forms a throttle point and which constantly connects the inlet P to the control chamber 144. The piston spring 146 tries to hold the control piston 142 in its basic position shown in FIG. Here, an annular groove 194 designed as a lubrication groove, which runs along the outer circumference of the control piston 142, is at least partially in register with the outlet T. A further second annular groove 196 is in this way between the annular groove 194 and the end of the control piston 142 facing the second pilot valve 124 arranged on its outer circumference that in the basic position shown in FIG. 2, this circumferential annular groove 196 is completely covered by the valve wall of the valve body 116. If the control piston 142 is moved from its basic position shown in FIG. 2 in FIG. 2 from bottom to top into its other end position, a connection between the control chamber 144 is established via a transverse bore 198 which is arranged in the bottom of the second annular groove 196 and a connecting line 102 running in the valve body 116, which leads into the upper transverse bore 132. Through the transverse bore 198 and the second annular groove 196, the control piston 142 thus has a passage which opens into the control chamber 144 and which can be connected to the leakage oil line L via the connecting line 102.

Bei diesem zweiten Ausführungsbeispiel des erfindungsgemäßen Speicherladeventils ist bei Erreichen des oberen Ladedruckes die Trennvorrichtung mit ihrem jeweiligen Dichtteil aus dem ersten Vorsteuerventil 122 und dem zwischen dem Zulauf P und dem Steueranschluß B liegenden Sperrventil in Form des Rückschlagventils 120 gebildet.In this second exemplary embodiment of the accumulator charging valve according to the invention, when the upper boost pressure is reached, the separating device with its respective sealing part is formed from the first pilot valve 122 and the check valve located between the inlet P and the control connection B in the form of the check valve 120.

Zur Verdeutlichung der erfindungsgemäßen Lehre wird im folgenden auch die Funktionsweise dieses zweiten Ausführungsbeispiels näher erläutert. Während des Ladevorganges fördert wiederum die Pumpe 118 über das eingebaute Rückschlagventil 120 in den Speicherkreis des Hydrauliksystems 110. Hierbei ist der Steuerkolben 142 druckausgeglichen und befindet sich in der durch die Kolbenfeder 146 bedingten, in der Fig.2 dargestellten Grundstellung. Der Zulauf P ist hierbei vom Ablauf T getrennt und das erste Vorsteuerventil 122 geöffnet, wohingegen das zweite Vorsteuerventil 124 geschlossen ist. Durch den Druckanstieg im Hydrauliksystem 110 und im Hydrospeicher 112 schließt zuerst das Vorsteuerventil 122 und bei Erreichen des oberen Ladedruckes öffnet das zweite Vorsteuerventil 124 durch den im Steuerraum 144 anstehenden Druck, der sich aus der Fluidzufuhr durch den Zulauf P hinter der Düse 192 ergibt. Es kommt zum Druckabfall im Steuerraum 144 des Steuerkolbens 142 und dieser verschiebt sich durch den im Zulauf P anstehenden Druck gegen die Kraft der als Rückstellmittel dienenden Kolbenfeder 146 in Fig.2 gesehen nach oben in seine Öffnungsrichtung. Mit Freigeben der Verbindung von Zulauf P nach Ablauf T wird die Federseite des Steuerkolbens 142 über die zweite Ringnut 196, die Querbohrung 198, die Verbindungsleitung 102, die Querbohrung 132 sowie die Leckölleitung L zur Leckölsammelstelle hin druckentlastet. Dadurch wird der Steuerkolben 142 entgegen der Wirkung der Kolbenfeder 146 endgültig geöffnet.In order to clarify the teaching according to the invention, the functioning of this second exemplary embodiment is also explained in more detail below. During the charging process, the pump 118 in turn delivers via the built-in check valve 120 into the storage circuit of the hydraulic system 110. The control piston 142 is pressure-balanced and is in the basic position shown in FIG. 2 caused by the piston spring 146. Inlet P is separated from outlet T and first pilot valve 122 is opened, whereas second pilot valve 124 is closed. Due to the pressure increase in the hydraulic system 110 and in the hydraulic accumulator 112, the pilot valve 122 closes first and when the upper boost pressure is reached, the second pilot valve 124 opens due to the pressure in the control chamber 144, which results from the fluid supply through the inlet P behind the nozzle 192. There is a pressure drop in the control chamber 144 of the control piston 142 and, due to the pressure present in the inlet P, the latter moves upward in its opening direction against the force of the piston spring 146 serving as a restoring means in FIG. When the connection of inlet P after outlet T is released, the spring side of the control piston 142 is relieved of pressure via the second annular groove 196, the transverse bore 198, the connecting line 102, the transverse bore 132 and the leakage oil line L to the leakage oil collection point. As a result, the control piston 142 is finally opened against the action of the piston spring 146.

Auf der Federseite des Steuerkolbens 142 steht dann hauptsächlich der in der Leckölleitung L herrschende Druck an, da das durch die Düse 192 ständig zulaufende Öl wieder über den angesprochenen Durchgang 196,198 zur weitgehend drucklosen Seite hin ablaufen kann. Das Hydrauliksystem 110 ist dann auf den oberen Ladedruck geladen und die Pumpe 118 fördert bei geringem Druckverlust von Zulauf P nach Ablauf T.The pressure prevailing in the leakage oil line L is then mainly present on the spring side of the control piston 142, since the oil which is constantly flowing in through the nozzle 192 can flow back to the largely unpressurized side via the passage 196, 198 mentioned. The hydraulic system 110 is then charged to the upper boost pressure and the pump 118 delivers from inlet P to outlet T with little pressure loss.

Der im Hydrauliksystem 110 herrschende Speicherdruck beaufschlagt dann das Rückschlagventil 120 und das erste Vorsteuerventil 122 hat jedoch aufgrund deren dichtenden Wirkung keinerlei Verbindung zum Steuerkolben 142 und damit zum Ablauf T. Durch die Anordnung gemäß dem zweiten Ausführungsbeispiel des erfindungsgemäßen Speicherladeventils ist also wiederum ventilintern im Bereich zwischen dem unteren und dem oberen Ladedruck eine völlig leckölfreie Absperrung des Hydrauliksystems 110 ermöglicht.The accumulator pressure prevailing in the hydraulic system 110 then acts on the check valve 120 and the first pilot valve 122 does not have any connection to the control piston 142 and thus to the outlet T due to their sealing effect allows the hydraulic system 110 to be completely leak-free shut-off at the lower and the upper boost pressure.

Wird in dem Hydrauliksystem 110 Öl entnommen, fällt der Druck solange ab, bis die am Vorsteuerventil 122 eingestellte Federkraft der Regelfeder 126 den Ventilstößel 184 betätigt und damit die Schließfläche 188 von der Sitzkante 190 zwecks Öffnen des Ventils abhebt. Über das derart geöffnete erste Vorsteuerventil 122 strömt dann über den Steueranschluß B das Steueröl wiederum über die zugehörige Verbindungsleitung 138 in den Steuerraum 144, das zusammen mit der Kolbenfeder 146 den Steuerkolben 142 in seine in der Fig.2 dargestellte Schließstellung nach unten bewegt, wobei die Entlastung der Kolbenrückseite zur Leckölseite hin geschlossen wird. Ferner wird die Verbindung von Zulauf P nach Ablauf T getrennt und der Ladezyklus von Zulauf P nach Steueranschluß B bis zum Erreichen des einstellbaren oberen Ladedruckes kann erneut beginnen.If oil is removed from the hydraulic system 110, the pressure drops until the spring force of the control spring 126 set on the pilot valve 122 actuates the valve tappet 184 and thus lifts the closing surface 188 from the seat edge 190 in order to open the valve. Via the first pilot valve 122 opened in this way, the control oil then flows again via the control connection B via the associated connecting line 138 into the control chamber 144, which together with the piston spring 146 moves the control piston 142 downward into its closed position shown in FIG. 2, the Relief of the piston back to the leak oil side is closed. Furthermore, the connection from inlet P after outlet T is disconnected and the charging cycle from inlet P to control connection B until the adjustable upper boost pressure can be reached again.

Nach Erreichen des oberen Ladedruckes fördert die Pumpe 118 bei geringem Druckverlust von P nach T. Durch Ölentnahme fällt der Druck im Hydrauliksystem ab, bleibt jedoch oberhalb des unteren Ladedruckes konstant.
Wird die Pumpe ausgeschaltet, so schiebt die Kolbenfeder 146 den Steuerkolben 142 aufgrund der ausbleibenden Ölförderung der Pumpe in seine Ausgangsstellung zurück.
Wird die Pumpe 118 wieder eingeschaltet, fördert diese über das Rückschlagventil 120 in den Hydrospeicher 112, der auf den oberen Ladedruck aufgeladen wird.
Bei den angesprochenen Rückschlagventilen 20,120 ist das jeweils verfahrbare Schließteil aus der abgerundeten Schließfläche einer Ventilkugel gebildet, die mit einer feststehenden ringförmigen Sitzkante am Ventilkörper dichtend in Anlage bringbar ist.After the upper boost pressure has been reached, the pump 118 conveys from P to T with a low pressure drop. The pressure in the hydraulic system drops due to oil extraction, but remains constant above the lower boost pressure.
If the pump is switched off, the piston spring 146 pushes the control piston 142 back into its starting position due to the lack of oil delivery by the pump.
If the pump 118 is switched on again, it pumps via the check valve 120 into the hydraulic accumulator 112, which is charged to the upper boost pressure.
In the check valves 20, 120 mentioned, the respectively movable closing part is formed from the rounded closing surface of a valve ball, which can be sealingly brought into contact with a fixed annular seat edge on the valve body.

Claims (8)

  1. Storage charging valve, which for connecting an inlet (P) supplying a hydraulic system (10), to an outlet (T) on reaching an adjustable upper charging pressure in the hydraulic system (10) and for cutting this connection on reaching an adjustable lower charging pressure in the hydraulic system (10), is provided with a control piston (42), which in one of its two switching positions cuts the connection between the inlet (P) and outlet (T) and in the other switching position establishes this connection, by means of a disconnecting device a control connection (B) connecting the hydraulic system (10) to the storage charging valve being disconnected from the outlet (T) and for adjusting the lower and the upper charging pressure, a first (22) or a second (24) servo valve being provided, characterised in that the disconnecting device comprises a closing piston (58) with a closing surface (72), which on reaching the adjustable upper charging pressure for the non-leaking closure of the connection forming a leakage point between the control connection (B) and the outlet (T), forms a leak-proof seat with a stationary seat surface (74), which is located in a displacing chamber (56) of the closing piston (58).
  2. Storage charging valve, which for connecting an inlet (P) supplying a hydraulic system (110), to an outlet (T), on reaching an adjustable upper charging pressure in the hydraulic system (110) and for cutting this connection on reaching an adjustable lower charging pressure in the hydraulic system (110), is provided with a control piston (142), which in one of its two switching positions cuts the connection between the inlet (P) and outlet (T) and in the other switching position establishes this connection, by means of a disconnecting device a control connection (B) connecting the hydraulic system (110) to the storage charging valve being disconnected from the outlet (T) and for adjusting the lower and the upper charging pressure a first (122) or a second (124) servo valve being provided, characterised in that the disconnecting device is formed from the first servo valve (122) and the stop valve (120) located between the inlet (P) and the control connection (B), which on reaching the adjustable upper charging pressure hermetically close the connection between the control connection (B) and the outlet (T) forming a leakage point.
  3. Storage charging valve according to Claim 1 or 2, characterised in that the force of restoring means (46, 146) attempts to keep the control piston (42, 142) in its position cutting the connection between the inlet and outlet (P, T), that a connection can be established between this inlet (P) and a control chamber (44, 144) of the control piston (42, 142) and that the control chamber (44, 144) is to be kept at a predetermined pressure by means of the second servo valve (24, 124).
  4. Storage charging valve according to Claim 3, characterised in that for establishing the connection between the inlet (P) and the control chamber, an orifice (192) seated in the control piston (142) is provided or a non-return valve (50) located in the control chamber (44) is to be actuated.
  5. Storage charging valve according to Claim 3 or 4, characterised in that connected between the inlet (P) and control connection (B) is a stop valve (20, 120) closing in the direction of the inlet (P) and that between this stop valve and the control connection (B) a branch (80, 180) leads to the first servo valve (22, 122).
  6. Storage charging valve according to one of Claims 3 to 5, characterised in that the control piston (142) comprises a passage (196, 198), which opens into the control chamber (144) and which can be connected to a leakage oil line (L, T).
  7. Storage charging valve according to Claim 1, characterised in that the control piston (42), which cooperates with the closing piston (58), forms a pressure-maintaining valve with the latter.
  8. Storage charging valve according to Claim 7, characterised in that the closing piston (58) with its active surface (70, 76) facing or remote from the control piston (42), can be exposed to the pressure prevailing in the inlet (P) or in the control connection (B) and which comprises on its active surface (70) facing the control piston (42), the closing part which preferably comprises a conical or rounded closing surface (72).
EP92901393A 1991-01-04 1992-01-01 Non-leaking storage charging valve Expired - Lifetime EP0565552B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4100071A DE4100071A1 (en) 1991-01-04 1991-01-04 LEAKAGE-FREE MEMORY CHARGE VALVE
DE4100071 1991-01-04
PCT/EP1992/000009 WO1992012350A1 (en) 1991-01-04 1992-01-01 Non-leaking storage charging valve

Publications (2)

Publication Number Publication Date
EP0565552A1 EP0565552A1 (en) 1993-10-20
EP0565552B1 true EP0565552B1 (en) 1995-04-12

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Application Number Title Priority Date Filing Date
EP92901393A Expired - Lifetime EP0565552B1 (en) 1991-01-04 1992-01-01 Non-leaking storage charging valve

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US (1) US5373865A (en)
EP (1) EP0565552B1 (en)
JP (1) JPH06504355A (en)
AT (1) ATE121168T1 (en)
DE (2) DE4100071A1 (en)
WO (1) WO1992012350A1 (en)

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DE19514745A1 (en) * 1995-04-21 1996-10-24 Rexroth Mannesmann Gmbh Load valve assembly for loading a memory
DE10350941A1 (en) * 2003-10-31 2005-06-02 Hydac Technology Gmbh Device for damping pressure surges
US8986253B2 (en) 2008-01-25 2015-03-24 Tandem Diabetes Care, Inc. Two chamber pumps and related methods
US8408421B2 (en) 2008-09-16 2013-04-02 Tandem Diabetes Care, Inc. Flow regulating stopcocks and related methods
AU2009293019A1 (en) 2008-09-19 2010-03-25 Tandem Diabetes Care Inc. Solute concentration measurement device and related methods
CA2769030C (en) 2009-07-30 2016-05-10 Tandem Diabetes Care, Inc. Infusion pump system with disposable cartridge having pressure venting and pressure feedback
US9180242B2 (en) 2012-05-17 2015-11-10 Tandem Diabetes Care, Inc. Methods and devices for multiple fluid transfer
US9173998B2 (en) 2013-03-14 2015-11-03 Tandem Diabetes Care, Inc. System and method for detecting occlusions in an infusion pump
US9885373B1 (en) 2016-10-11 2018-02-06 Honeywell International Inc. Leak-free piston style accumulator

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DE1049704B (en) * 1959-01-29 Robert Bosch Gmbh Stuttgart Pressure medium system, in particular hydraulic system for lifting devices on vehicles
US2545712A (en) * 1944-06-27 1951-03-20 Merit Engineering Inc Unloading valve
US2737966A (en) * 1951-10-15 1956-03-13 Siam Pressure regulator
DE1043819B (en) * 1956-09-27 1958-11-13 Bosch Gmbh Robert Pressure medium system, especially hydraulic system for lifting devices on vehicles
US3024732A (en) * 1957-02-01 1962-03-13 Sargent Engineering Corp Regulating valve
GB965656A (en) * 1960-04-12 1964-08-06 Pratt Prec Hydraulics Ltd Improvements in or relating to pressure responsive valves
FR84166E (en) * 1963-07-17 1964-12-04 Citroen Sa Andre Device maintaining the pressure in hydraulic circuits between two given values
FR1319685A (en) * 1962-04-12 1963-03-01 Gury Const Hydromecaniques Sa Hydraulic circuit breaker with adjustable cut-off and cut-off pressures
DE1807436A1 (en) * 1968-11-07 1970-06-04 Gewerk Eisenhuette Westfalia Shut-off valve for hydraulic pumping systems
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DE3334189C2 (en) * 1983-09-22 1986-04-10 Integral Hydraulik & Co, 4000 Düsseldorf Shut-off valve
DE3608100A1 (en) * 1986-03-12 1987-09-17 Integral Hydraulik Co Cut-off valve
DE3744178A1 (en) * 1987-12-24 1989-07-06 Integral Hydraulik Co Hydraulic accumulator-charging valve

Also Published As

Publication number Publication date
JPH06504355A (en) 1994-05-19
EP0565552A1 (en) 1993-10-20
DE4100071A1 (en) 1992-07-09
DE59201918D1 (en) 1995-05-18
US5373865A (en) 1994-12-20
WO1992012350A1 (en) 1992-07-23
ATE121168T1 (en) 1995-04-15

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