EP1332290A2 - Soupape de coupure de pression - Google Patents

Soupape de coupure de pression

Info

Publication number
EP1332290A2
EP1332290A2 EP01992837A EP01992837A EP1332290A2 EP 1332290 A2 EP1332290 A2 EP 1332290A2 EP 01992837 A EP01992837 A EP 01992837A EP 01992837 A EP01992837 A EP 01992837A EP 1332290 A2 EP1332290 A2 EP 1332290A2
Authority
EP
European Patent Office
Prior art keywords
pilot
piston
pressure
valve
pilot piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP01992837A
Other languages
German (de)
English (en)
Other versions
EP1332290B1 (fr
Inventor
Günter KRENZER
Karl Josef Meyer
Peter Lauer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bosch Rexroth AG
Original Assignee
Bosch Rexroth AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bosch Rexroth AG filed Critical Bosch Rexroth AG
Publication of EP1332290A2 publication Critical patent/EP1332290A2/fr
Application granted granted Critical
Publication of EP1332290B1 publication Critical patent/EP1332290B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • 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
    • 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
    • Y10T137/263—Plural sensors for single bypass or relief valve
    • 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
    • Y10T137/2635—Pilot valve operated
    • 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
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7762—Fluid pressure type
    • Y10T137/7764—Choked or throttled pressure type
    • Y10T137/7766—Choked passage through main valve head
    • 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
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7758—Pilot or servo controlled
    • Y10T137/7762—Fluid pressure type
    • Y10T137/7769—Single acting fluid servo
    • Y10T137/777—Spring biased

Definitions

  • the invention relates to a pilot-operated pressure cut-off valve which, when an upper system limit pressure is reached in a hydraulic system with a hydraulic accumulator, connects an inlet feeding the hydraulic system to an outlet to a tank and disconnects this connection when the system pressure is removed by removing hydraulic fluid from the hydraulic accumulator has dropped to a lower system limit pressure and which, according to the preamble of patent claim 1, has a main control piston and, for controlling the main control piston, a pilot valve arrangement with two pilot pistons and two pilot springs, by means of which adjustment the upper system limit pressure and the lower system limit pressure can be set independently of one another.
  • Such a pilot operated pressure cut-off valve is e.g. known from DE 41 12 065 A1 or from DE 36 08 100 C2.
  • the pilot valve arrangement consists of two complete pilot valves, each with a valve housing, with a pilot piston in a bore in the valve housing and with a pilot spring located in a spring chamber, the preload of which can be changed using an adjusting screw.
  • the two pilot valves are placed one above the other on the housing of the main stage. This pressure shut-off valve is quite large and is relatively expensive.
  • the pilot valve arrangement has only one valve housing. Two valve bores, each of which receives one of the two pilot pistons, run in this at a distance and parallel to one another.
  • the two pilot springs are housed side by side in an extension of the valve bores in a cover attached to the valve housing of the pilot valve arrangement.
  • the pilot valve arrangement is still quite complex.
  • pilot operated pressure cut-off valves in which the pilot valve arrangement has only one pilot piston and one pilot spring and an adjustment of the one system limit pressure always entails an adjustment of the other system limit pressure.
  • the difference between the two limit pressures is a percentage of the upper system limit pressure, this percentage depending on the size of an area difference on the pilot piston and on the bias of the pilot spring.
  • a pilot-operated pressure shut-off valve in which the upper system limit pressure and the lower system limit pressure cannot be set independently of one another, is known, for example, from data sheet RE 26 411 / 03.98 by the applicant.
  • the invention has for its object to develop a pilot operated pressure shut-off valve with the features from the preamble of claim 1 so that the pilot valve assembly is compact and simple, inexpensive to manufacture and against a pilot valve assembly of a pressure shut-off valve, in which the upper system limit pressure and the lower system limit pressure cannot be set independently, is interchangeable.
  • the desired aim is achieved in that, in accordance with the characterizing part of claim 1, the two pilot pistons, the two pilot springs and the two adjusting screws are arranged concentrically one inside the other, the two pilot pistons being mechanically completely independently adjustable.
  • the pilot valve arrangement is very compact and of low height. Only one valve housing is required for the pilot valve arrangement. This can easily be built on a main stage instead of a conventional pilot valve arrangement, which does not allow the two limit pressures to be set independently of one another.
  • the machining of the valve housing of a pilot valve arrangement according to the invention is considerably simplified, since only one valve bore is necessary for the two pilot pistons.
  • the compact con- The central arrangement of the pilot pistons, the pilot springs and the adjusting screws also enables a previously unrealizable cartridge design.
  • the complete mechanical independence of the two pilot pistons with regard to their movement possibilities according to claim 2 can be achieved in a simple manner in that the outer pilot piston is located with an outer collar between two stops fixed to the housing, that one stop is formed on a bushing inserted in the valve housing and that the inner pilot piston penetrates the socket and is located with an outer collar between the socket and another insert inserted into the valve housing.
  • the first pilot piston switches reliably when the upper system limit pressure is reached and remains in one switching position until the system pressure drops to the lower system limit pressure
  • it is a step piston according to claim 3.
  • a pressure chamber is formed in front of the step surface, in which pump pressure is present when the main step is closed and which is relieved of pressure by or for switching over the first pilot piston when the upper system limit pressure is reached.
  • the pressure in the pressure chamber acts on the first pilot piston on the step surface in the same direction as the first pilot spring. Contrary to the direction of action of the first pilot spring, the first pilot piston is acted upon by the system pressure on a large, first effective area.
  • the minimum lower system limit pressure is determined by the area difference between the first effective area on which the system pressure generates a force and the second effective area on which the pump pressure generates a force.
  • the step surface of the first pilot piston or more generally the active surface on the first pilot piston, on which the pump pressure exerts a force directed in the same direction as the spring force. testifies to at least a third of the size of the large effective area on which the system pressure creates a counterforce. With such a size ratio, the first pilot piston already switches over.
  • the step area has about two thirds the size of the large effective area. Basically, the step area can also be made larger in comparison to the large effective area. However, this is no longer in the sense of a compact design.
  • a size ratio of two thirds is sufficient to enable the greatest desired difference between the upper system limit pressure and the lower system limit pressure.
  • the second pilot piston is designed as a stepped piston and is acted upon by the pump pressure on the step surface in the effective direction of the second pilot spring, while it is acted upon by the system pressure on a large, first active surface against the effective direction of the second pilot spring. This ensures that the second pilot piston reaches the switching position determined by the second pilot spring in the entire pressure and quantity range of the pressure cut-off valve.
  • the size of the step surface of the second pilot piston is preferably in the range of 5 percent of the large end-side active surface of the second pilot piston.
  • the aim aimed at by the invention can be achieved regardless of which of the two pilot pistons is the outer pilot piston that accommodates the other pilot piston.
  • the first pilot piston is the hollow piston in which the second pilot piston is guided.
  • control arrangement according to claim 9 is particularly favorable, however, if the two pilot pistons are arranged one inside the other, since, as stated in claim 11, the relief of the control chamber on the main control piston, i.e. the opening of the two flow cross sections lying in series with one another, is low construction effort is possible. If the first pilot piston is the outer pilot piston, the fluid path over the two flow cross sections is particularly simple in a configuration according to patent claim 12.
  • the safety of switching over to the connection inlet to the system is also increased by an embodiment according to claim 14. Because the second pilot piston makes a further path in the closing direction due to the further breakthrough of the first pilot piston. If, due to the pressure increase in the outer annular space, the first pilot piston moves faster than the second pilot piston in the closing direction, its first openings on the outside are already covered by the control edge fixed to the housing if these are opened again on the inside. The slight play between the pilot piston and between the first pilot piston and the housing is used specifically for a small leakage flow from the further breakthrough into the relief space, the leakage flow also being able to include the first breakthroughs and making up part of the total leakage flow.
  • the second pilot spool takes the larger route.
  • the opening cross section between the first Breakthroughs and the control edge fixed to the housing no longer has to be tolerated as precisely and the pressure cut-off valve nevertheless switches reliably.
  • FIG. 1 shows the first exemplary embodiment in a longitudinal section through the pilot valve arrangement
  • FIG. 2 shows a circuit diagram of the exemplary embodiments shown
  • FIG 3 shows the second exemplary embodiment, which differs from the first exemplary embodiment in that there is a further bore in the wall of the first pilot piston that can be influenced by the inner, second pilot piston, and
  • FIG. 4 shows a development of the outer pilot piston from FIG. 3 in the region of its bores which cooperate with a control edge fixed to the housing and with a control edge on the second pilot piston.
  • the pilot-controlled pressure shut-off valve shown comprises a main stage 10 and a pilot valve arrangement 11, which are each identified by a dash-dotted rectangle.
  • the main stage 10 has an inlet connection 12, an outlet connection 13 and a system connection 14. From this a system line 15 branches off, to which a hydraulic accumulator 16 and directional control valves (not shown in more detail) for controlling hydraulic consumers are connected.
  • the inlet connection 12 and the system connection 14 are connected to one another via a check valve 17, which opens from the inlet connection to the system connection.
  • the main control piston is guided on a first diameter in a bore 21 of the housing 22 of the main stage and can be seated with a truncated cone surface 23 on a seat edge 24, the diameter of which is slightly smaller than the guide diameter.
  • the bore 21 is closed on one side by the valve housing 25 of the pilot valve arrangement 11 which is placed on the valve housing 22.
  • a control chamber 26 is formed in the bore, from which a weak helical compression spring 27 is received, which is supported on the housing 25 and the main control piston 20 and loads it in the direction of the seat edge 24.
  • the end face 28 of the main control piston 20 lying within the seat edge 24 delimits a space which is open towards the inlet connection 12. This space is fluidly connected to the control space 26 via a nozzle 29 formed in the main control piston 20.
  • a hydraulic pump 30, which is driven by an electric motor 31, is connected to the inlet connection 12.
  • the hydraulic fluid delivered by the hydraulic pump 30 flows via the check valve 17 to the system line 15 and thus to the hydraulic accumulator 16. If less pressure medium is taken from the system line 15 than it is flowing in, the pressure in it and in the hydraulic accumulator 16 increases.
  • the main stage 10 of the pressure cut-off valve shown is now controlled so that the main control piston 20 opens when the pressure in the hydraulic accumulator 16 has reached an upper system limit pressure.
  • the hydraulic pump 30 conveys the hydraulic fluid drawn in from the tank 32 via the inlet connection 12, via the flow cross section between the seat edge 24 of the housing 22 and the truncated cone surface 23 of the main control piston 20 and via the outlet connection 13 in circulation to the tank 32.
  • the pressure in the hydraulic reservoir 16 drops below. Is closing When the set lower system limit pressure is reached, the main control piston 20 closes the flow cross section between the inlet connection 12 and the outlet connection 13, so that the hydraulic pump 30 delivers again into the system line 15. When conveying in circulation, the pressure in the inlet connection 12 is low and essentially determined by the force of the helical compression spring 27.
  • the check valve 17 prevents pressure fluid from the system line 15 from flowing into the inlet connection and via the main control piston 20 and the outlet connection 13 to the tank 32.
  • the main control piston 20 is controlled by the pilot valve arrangement 11, which, in terms of circuitry, has two pilot valves 40 and 41, which are designed as 2/2-way valves and which are in series with one another between the control chamber 26 on the main control piston 20 and the drain connection 13, whereby A relief line 42 leads from the pilot valve 40 through the pilot valve housing 25 and the valve housing 22 of the main stage 10 to the drain connection 13.
  • the control chamber 26 is connected to the pilot valve 41 via a damping nozzle 43.
  • the first pilot valve 40 has a first pilot piston 44, which is acted upon in the direction of the closed position by a first helical compression spring 45, the bias of which can be changed to adjust the upper system limit pressure.
  • the pilot piston 44 In the closing direction, the pilot piston 44 is acted upon by the accumulator pressure, that is to say by the system pressure, on a large active surface 46. With the helical compression spring 45 in the closing direction, the pressure prevailing between the damping nozzle 43 and the pilot valve 41 also acts on an active surface 47, the size of which is approximately two thirds of the size of the active surface 46. In the static state of the main control piston 20, this pressure is approximately equal to the pressure in the control chamber 26.
  • the pilot valve 41 has a second pilot piston 48 which is acted upon in the closing direction by a second helical compression spring 49, the pretension of which can be changed to adjust the lower system limit pressure.
  • the pilot piston 48 In the closing direction, the pilot piston 48, just like the pilot piston 44, is acted upon by the system pressure, specifically on an active surface 50.
  • the screw Compression spring 49 in the opening direction on the pilot piston 48 acts on the pressure present between the damping nozzle 43 and the pilot valve 41.
  • the size of the effective area 51 for this pressure is only about 5 percent of the size of the effective area 50.
  • the space in which the helical compression springs 45 and 49 are located lies on the relief line 42.
  • the pressure in the hydraulic accumulator 16 increases with the inflow of pressure medium and finally becomes so large that the differential area between the two active areas 46 and 47 is sufficient as a pressure application area so that a flow cross section is opened in the pilot valve 40.
  • the pressure at the active surface 47 begins to drop immediately, so that the pilot valve 40 switches through to its open position. Hydraulic fluid can now flow out of the control chamber 26 via the two pilot valves 40 and 41 and the relief line 42 to the tank 32.
  • the main control piston 20 is relieved of pressure on the spring side and opens.
  • the pressure in the inlet connection 12 drops to a low value determined by the prestress of the helical compression spring 27.
  • the check valve 17 closes.
  • the hydraulic fluid conveyed by the hydraulic pump 30 flows back to the tank 32 via the flow cross section between the seat edge 24 of the housing 22 and the truncated cone surface of the main control piston 20.
  • the pressure by which the pilot valve 40 can be brought into its open position is equal to the upper system limit pressure. Its height is determined by the preload of the helical compression spring 45 and can be changed by changing this preload.
  • the pressure in the control chamber 26 becomes equal to the pressure in the inlet connection 12, so that the main control piston 20, under the action of the helical compression spring 27 and outside the seat edge 24, has an excess area attacking pump pressure closes.
  • the pressure in the inlet connection 12 and in the control chamber 26 and on the active surfaces 47 and 51 thus rises to the system pressure, which is currently the same as the lower system limit pressure.
  • the pilot valve 40 Even before this lower system limit pressure is reached on the active surface 47, the pilot valve 40 also reaches its closed position. Due to the inflow of hydraulic fluid to the hydraulic accumulator 16, the system pressure rises, and because of the very small effective area 51 in comparison to the effective area 50, a slight increase above the lower system limit pressure is sufficient to bring the pilot valve back into its open position.
  • the active surface 47 should be at least one third the size of the active surface 46. If, on the other hand, an upper system limit pressure is set by adjusting the helical compression spring 45, the ratio of the size of the surface 47 to the size of the surface 46 results in a pressure acting on the active surface 46, against which the helical compression spring 45 controls the pilot valve 40 when the active surface 47 is unloaded could bring a switching operation of the pilot valve 41 into the closed position. This pressure is therefore the minimum lower system limit pressure that can be obtained with a given upper system limit pressure. Is the ratio between the area 47 and the area
  • the minimum lower system limit pressure would be 140 bar. Is the ratio of the area
  • the minimum lower system limit pressure is 70 bar.
  • the lower system limit pressure can be set within this range by adjusting the helical compression spring 49.
  • the presence of the active surface 51 also places a restriction on the minimum distance between the upper system limit pressure and the lower system limit pressure.
  • the two pilot valves 40 and 41 are integrated into one another in a very compact manner, so that, as can be seen in particular from the section according to FIG. 1, they appear as a single valve. Otherwise, the components of the main stage, the check valve 17, a hydraulic accumulator 16 and a hydraulic pump and an electric motor 31 are shown in FIG. 1 in a manner similar to that in FIG. 3 and provided with the same reference numbers as in FIG.
  • the pilot valve arrangement according to FIG. 1 has a plate-shaped valve housing 25, into which a large-volume blind bore 55 is made from one side surface.
  • a multiply stepped valve bore 56 opens centrally into the blind bore 55 and has its largest diameter on the opposite side surface and is closed there by a screw plug 57.
  • the smallest The diameter of the valve bore 56 is immediately following the bottom 58 of the blind bore 55.
  • a stepped hollow piston is guided as the first pilot piston 44, which projects out of the valve bore 56 into the blind bore 55.
  • An annular space 61 is formed between a step surface 59 of the pilot piston 44, which is directed away from the screw plug 57, and an axially opposite step surface 47 of the valve bore 56, into which a channel 62 leading radially through the valve housing 25 opens.
  • the annular space 61 is fluidly connected to the control space 26 on the main control piston via this channel, the damping nozzle 43 being screwed into the channel 62.
  • the pilot piston 44 is acted upon by the pressure prevailing in the annular space 61 on a resulting active surface, which is equal to the stepped surface 47 of the valve bore 56, in the direction of the screw plug 57.
  • an outer collar 63 with which the pilot piston 44 on the one hand in the direction of the screw plug 57 to a plug 64 inserted in the bore 59 and held in place and in The opposite direction can strike a further step 65 of the valve bore 56.
  • the displacement path of the pilot piston 44 is defined by the two axial stops and the axial extent of the outer collar 63.
  • a further bushing 66 Between the bushing 64 and the screw plug 57 there is a further bushing 66. This is pressed by the screw plug 57 against the bushing 64 and this in turn is pressed against a step of the valve bore 56.
  • the first pilot piston 44 has a central axial bore 69 in the center, in which the second pilot piston 48 can be axially displaced.
  • the axial bore 69 is a stepped bore with a bore section of larger diameter that opens to the outside on the end face of the pilot piston 44 facing the bushing 64, and with a bore section of smaller diameter that is open to the blind bore 55 of the housing 25.
  • the cross sections of the two bore sections of the bore 69, which are in the step surface 51 on the pilot piston 44 merge into each other, only differ by about 5 percent.
  • the axial bore 69 is connected to the outside of the pilot piston 44 via a plurality of openings 70 located axially at the same height. If, as shown in FIG.
  • the pilot piston 44 bears against the bush 64, the openings are covered on the outside by the wall section of the valve bore 56 located between the step surface 47 of the valve bore 56 and the bottom 58 of the blind bore 55.
  • the edge between the bottom 58 of the blind bore 55 and the valve bore 56 forms a control edge 71 fixed to the housing, which cooperates with the openings 70. It is run over by the openings 70 and thus a flow cross-section is produced from the openings 70 into the blind bore 55 when the valve slide 44 is moved away from the bushing 64 to the step 65 of the housing 25.
  • the pilot piston 48 is stepped and has a guide section in the area of the smaller diameter bore section and a slightly larger diameter guide section in the larger diameter bore section.
  • the two guide sections are spaced far apart, the diameter of the piston section between the two guide sections being reduced once again compared to the diameter of the smaller guide section.
  • an annular space 72 has formed radially between the outer pilot piston 44 and the inner pilot piston 48 and axially between the two guide sections thereof. This is permanently connected to the annular chamber 61 and thus to the control chamber 26 on the main control piston 20 via a radial bore 73 in the pilot piston 44.
  • the pressure present in the annular space 72 generates a force acting in the direction of the locking screw 57 at an annular surface of the pilot piston 48 corresponding to the size of the step surface 51 of the pilot piston 44.
  • the outer edge 74 on the end face of the guide section of smaller diameter of the pilot piston 48 facing the annular space 72 forms a control edge which interacts with the openings 70 on the pilot piston 44 and which is shown in FIG. showed switching position of the pilot piston 48 between the step surface 51 on the pilot piston 44 and the openings 70 and which is shifted so far in the other switching position of the pilot piston 48 that, regardless of the current switching position of the pilot piston 44, an open fluidic connection between the annular space 72 and the Breakthroughs 70 there.
  • the second pilot piston 48 projects in the direction of the locking screw 57 beyond the pilot piston 44, passes through an inner collar of the bushing 64 and is caught between this inner collar and the bushing 66 with a head 75.
  • the socket 66 is provided on the outside with a recess 76, which is open to a bore 77 of the housing 25, which is fluidly connected to the system line 15 and thus to the hydraulic accumulator 16.
  • the end faces of the pilot pistons 44 and 48 facing the screw plug 57 are exposed to the pressure in the recess 76, that is to say the system pressure, via radial and axial bores in the bushes 54 and 66. This pressure generates a force on the pilot piston, which forces it away from the bushes 64 and 66 in the direction of the blind bore 55.
  • the active surface on the pilot piston 44 is equal to an annular surface with an inner diameter that is equal to the diameter of the larger section of the axial bore 69 and with an outer diameter that is equal to the outer diameter of the step surface 47 of the housing 25.
  • the effective area on the pilot piston 48 is equal to the cross-sectional area of the larger guide section of this piston.
  • the two pilot springs 45 and 49 are located in the blind bore 55 and, like the pilot pistons 44 and 48, are arranged concentrically one inside the other.
  • the outer pilot spring 45 is supported by a spring plate 77 on the first pilot piston 44, which loads it in the direction of the locking screw 57.
  • it is supported on an adjusting screw 78 which is screwed into the blind hole 55.
  • the inner pilot spring 49 is supported by a spring plate 78 on the pilot piston projecting beyond the pilot piston 44 48 and also loads it in the direction of the locking screw 57.
  • the pilot spring 49 is supported on an adjusting screw 80 which is screwed centrally into the adjusting screw 78 and can be adjusted axially to the adjusting screw 78 by turning.
  • the blind bore 55 is part of the relief channel 42, which also includes a transverse bore 81 in the housing 25, via which the relief fluid path leads to the tank 32.
  • the pilot pistons 44 and 48 assume the switching positions shown in the diagram in FIG. 2.
  • the openings 70 in the pilot piston 44 are covered on the inside by the pilot piston 48 and on the outside by the housing 25.
  • Pump pressure is present in the control chamber 26 on the main control piston 20 and in the annular spaces 61 and 72. This acts on the pilot piston 48 on a surface with the size of the surface 51 in the same direction as the pilot spring 49.
  • the resulting active surface on which the pump pressure acts on the pilot piston 44 does not exactly correspond to the size of the surface 47, but is opposite the surface 47 reduced by the area 51.
  • the corresponding step of the valve bore 56 is provided with the reference number 47 from FIG. 2.
  • the pilot piston 48 When loading for the first time, the pilot piston 48 thus switches from the switch position shown in FIG. 1 to the other switch position if the system pressure is so high that it is one of the surfaces of an area which is as large as the area 50 reduced by the area 51 Force of the pilot spring 49 generates the same force.
  • the openings 70 in the pilot piston 44 are thus opened on the inside toward the annular space 72 and thus towards the control space 26 on the main control piston 20.
  • the pilot piston 44 is moved from the switching position shown in Figure 1 in the direction of its second switching position.
  • the openings 70 are also opened on the outside, so that pressure fluid can flow out of the annular space 61 via the radial bore 73, the annular space 72 and the openings 70 into the blind bore 55 and from there into the tank 32.
  • the pressure drop caused thereby in the annular space 61 leads to a rapid switching through of the pilot piston 44.
  • Tank pressure is now present in the annular spaces 61 and 72.
  • the effective area on which the system pressure acts on the pilot piston 48 is now equal to the cross section of the larger guide section of the pilot piston 48. Accordingly, the compressive force acting against the pilot spring 49 is also greater than when the hydraulic accumulator 16 was loaded for the first time.
  • the pilot piston 48 therefore becomes returned to the switching position shown in Figure 1, which is slightly lower than the pressure that was sufficient when the hydraulic accumulator 16 was first loaded to bring the pilot piston 48 against the pilot spring 49 into the switching position not shown in Figure 1.
  • the openings 70 in the pilot piston 44 are closed on the inside, so that the pressure in the annular spaces 61 and 72 again becomes equal to the pressure in the feed from the pump to the main control piston 20.
  • the main control piston 20 therefore closes the connection between the inlet and the tank 32.
  • the pressure in the inlet and in the annular spaces 61 and 72 increases to the system pressure, as a result of which the pilot piston 44 is also returned to the switching position shown in FIG. This happens rather than the pilot piston 48 is moved again against the spring 49 into the other switching position, in which the openings 70 are opened again on the inside.
  • the exemplary embodiment according to FIGS. 3 and 4 is largely identical to the exemplary embodiment according to FIG. 1.
  • the same reference numbers as in FIG. 1 are used for the pilot pistons and the different bores and spaces. Only the differences are discussed below. For the rest, reference is made to the description of FIG. 1.
  • a first difference is that the first pilot piston 44 does not now run directly in a plate-shaped housing as in the exemplary embodiment according to FIG. 1, but that the pilot valve is designed in a cartridge design and has a valve sleeve 85 which receives the pistons and springs and which in a valve plate 86 is screwed in.
  • the first pilot piston 44 has, in the region of bores 84 which correspond to the openings 70 according to FIG. 1 and of which four of the same size are uniformly distributed over the circumference in the same radial plane, a further smaller bore 87 which is seen in the circumferential direction , is located centrally between two bores 84, but is offset in the axial direction relative to the bores 84 in the direction of the step in the axial bore 69 of the pilot piston 44.
  • the control edge 74 leaves the bore 87 partially open on the inside when the bores 84 are already covered on the inside.
  • the diameter of the bores 84 in the present case is 1.2 mm and the diameter of the bore 87 is 0.7 mm.
  • the two pilot pistons 44 and 48 are shifted to the right up to the stop.
  • the second pilot piston 48 initially moves to the left and closes the bores 84 on the inside, so that the pressure in the annular space 61 rises.
  • a certain pressure which is dependent on the upper system limit pressure and the lower system limit pressure, must be reached so that the pilot piston 44 switches back. Because of the increased leakage compared to the first exemplary embodiment because of the bore 87, the second pilot piston 48 continues to move and also closes the bore 87.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Driven Valves (AREA)
  • Control Of Fluid Pressure (AREA)
  • Safety Valves (AREA)
  • Sliding Valves (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

L'invention concerne une soupape de coupure de pression pilotée comprenant un piston de commande principal (20), qui relie une arrivée (12), par laquelle un fluide peut alimenter un système hydraulique, à une sortie (13), en prenant une première position de commutation, lorsqu'une pression limite vers le haut est atteinte dans ce système hydraulique, et sépare cette arrivée de la sortie (13), en prenant une deuxième position de commutation, lorsqu'une pression limite vers le bas du système est atteinte. Cette soupape de coupure de pression comprend un ensemble soupape pilote (11). Sur une soupape de coupure de pression de ce type, cet ensemble soupape pilote (11) doit être compact et de conception simple, contrairement à des ensembles soupape pilote d'une soupape de coupure de pression, sur laquelle les pressions limites vers le haut et vers le bas ne peuvent pas être réglées indépendamment l'une de l'autre. En outre, cet ensemble doit pouvoir être remplacé et produit de manière économique. A cet effet, les deux pistons de pilotage (44, 48), les ressorts de pilotage (45, 49) et les deux vis de réglage (78, 80) sont agencés les uns dans les autres de manière concentrique, les deux pistons de pilotage (44, 48) pouvant être réglés de manière mécanique et entièrement indépendante l'un de l'autre.
EP01992837A 2000-11-04 2001-10-19 Soupape pilotée de coupure de pression et arrangement de valve pilote Expired - Lifetime EP1332290B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10054704 2000-11-04
DE10054704A DE10054704A1 (de) 2000-11-04 2000-11-04 Vorgesteuertes Druckabschaltventil
PCT/EP2001/012094 WO2002036967A2 (fr) 2000-11-04 2001-10-19 Soupape de coupure de pression

Publications (2)

Publication Number Publication Date
EP1332290A2 true EP1332290A2 (fr) 2003-08-06
EP1332290B1 EP1332290B1 (fr) 2007-03-14

Family

ID=7662144

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01992837A Expired - Lifetime EP1332290B1 (fr) 2000-11-04 2001-10-19 Soupape pilotée de coupure de pression et arrangement de valve pilote

Country Status (5)

Country Link
US (1) US7204266B2 (fr)
EP (1) EP1332290B1 (fr)
JP (1) JP2004515723A (fr)
DE (2) DE10054704A1 (fr)
WO (1) WO2002036967A2 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE502005003090D1 (de) * 2004-02-05 2008-04-17 Bosch Rexroth Ag Messblendenanordnung für ein hydraulisches stromteil- und stromsummiergerät
JP4600071B2 (ja) * 2005-02-15 2010-12-15 アイシン精機株式会社 自動変速機の油圧制御装置
EP1895168B1 (fr) * 2006-09-01 2009-05-06 Parker Hannifin Aktiebolag Arrangement de soupapes
US8683795B1 (en) 2010-05-04 2014-04-01 The Boeing Company Control valve for a hydraulic refueling boom system
CN107606292B (zh) * 2017-09-29 2019-03-12 中国长江电力股份有限公司 一种嵌套式双活塞先导阀
CN113898619B (zh) * 2021-09-10 2022-10-11 常德中联重科液压有限公司 蓄能器充液阀及液压制动系统

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US3273581A (en) * 1966-09-20 Pilot operated unloading valve having relatively
DE1043819B (de) * 1956-09-27 1958-11-13 Bosch Gmbh Robert Druckmittelanlage, insbesondere Hydraulikanlage fuer Hebeeinrichtungen auf Fahrzeugen
US3024732A (en) * 1957-02-01 1962-03-13 Sargent Engineering Corp Regulating valve
DE1807436A1 (de) * 1968-11-07 1970-06-04 Gewerk Eisenhuette Westfalia Abschaltventil fuer hydraulische Pumpanlagen
US3621881A (en) * 1970-08-03 1971-11-23 Acf Ind Inc High-low pressure pilot valve mechanism
US4114637A (en) * 1976-12-20 1978-09-19 Double A Products Company Variable differential pressure unloading valve apparatus
DE3401369A1 (de) 1983-01-26 1984-08-02 Beringer-Hydraulik GmbH, Neuheim, Zug Vorgesteuertes druckbegrenzungsventil
DE3401360A1 (de) * 1984-01-17 1985-08-01 Hans Dieter Wilhelm 4050 Mönchengladbach Goeres Salzkraftwerk zur energielieferung
AT386258B (de) * 1985-03-15 1988-07-25 Hoerbiger Ventilwerke Ag Steuerungsanordnung fuer pneumatische arbeitszylinder
DE3608100A1 (de) * 1986-03-12 1987-09-17 Integral Hydraulik Co Abschaltventil
DE4112065C2 (de) * 1991-04-12 1995-06-29 Rexroth Mannesmann Gmbh Vorgesteuertes Druckabschaltventil mit einstellbarer Schaltdruckdifferenz
KR100445944B1 (ko) * 1996-05-29 2004-11-03 가부시끼가이샤 요꼬따 세이사꾸쇼 자동 조정 밸브 장치

Non-Patent Citations (1)

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See references of WO0236967A2 *

Also Published As

Publication number Publication date
EP1332290B1 (fr) 2007-03-14
US20040099828A1 (en) 2004-05-27
DE50112199D1 (de) 2007-04-26
US7204266B2 (en) 2007-04-17
WO2002036967A3 (fr) 2003-02-13
JP2004515723A (ja) 2004-05-27
WO2002036967A2 (fr) 2002-05-10
DE10054704A1 (de) 2002-05-08

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