EP0883753B1 - Soupape de frein a maintien de charge - Google Patents

Soupape de frein a maintien de charge Download PDF

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Publication number
EP0883753B1
EP0883753B1 EP97907055A EP97907055A EP0883753B1 EP 0883753 B1 EP0883753 B1 EP 0883753B1 EP 97907055 A EP97907055 A EP 97907055A EP 97907055 A EP97907055 A EP 97907055A EP 0883753 B1 EP0883753 B1 EP 0883753B1
Authority
EP
European Patent Office
Prior art keywords
pilot
piston
valve
opening
control
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.)
Expired - Lifetime
Application number
EP97907055A
Other languages
German (de)
English (en)
Other versions
EP0883753A1 (fr
Inventor
Hubert Häussler
Ivan Hristov
Hans Staiger
Josef ZÜRCHER
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.)
Bucher Hydraulics AG
Original Assignee
Bucher Hydraulics AG
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Filing date
Publication date
Application filed by Bucher Hydraulics AG filed Critical Bucher Hydraulics AG
Publication of EP0883753A1 publication Critical patent/EP0883753A1/fr
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Publication of EP0883753B1 publication Critical patent/EP0883753B1/fr
Anticipated expiration legal-status Critical
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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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/01—Locking-valves or other detent i.e. load-holding devices
    • F15B13/015—Locking-valves or other detent i.e. load-holding devices using an enclosed pilot flow valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B2013/008—Throttling member profiles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or 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
    • Y10T137/2544—Supply and exhaust type

Definitions

  • the invention relates to a hydraulically controllable load holding brake valve for double-acting consumers according to the preamble of claim 1.
  • the load holding brake valve has as a pilot valve a ball seat valve, which is very sensitive control by the pilot piston required to one of Starting to allow steady flow increases and a leaping Avoid opening behavior.
  • a progressive opening behavior is understood here to mean that the Opening is essentially proportional to the control pressure, anyway but a defined, jerk-free and shock-free dependency between the opening cross-section and control pressure (i.e. the 1st and 2nd derivative of the function: "Opening the valve above the control pressure" are for any change in the Control pressure finite and steady).
  • pilot piston has one following its sealing surface Piston shaft (pilot tappet) with little play in the seat bore to be led.
  • the piston skirt has a series of several over its length Cross-sectional areas. The maximum cross section follows and corresponds to that Seat section. In essence, it has very little play the seat bore (pilot channel). The area with the maximum cross section is very short and can go to zero.
  • the throttle area It forms the valve lifter a throttle point in the seat bore (pilot channel), its throttling effect when moving the plunger and / or the resulting appearance the pilot channel steadily - and preferably progressively - becomes smaller.
  • the throttling effect is so large that it is much larger than the throttling effect of the compensating throttle. From there the throttling effect takes place in relation to the pilot channel with increasing control path of the control piston and displacement of the pilot tappet in such a way that the function of the throttle effect is constant over the displacement length of the pilot ram.
  • the throttling effect Preferably takes the throttling effect initially slight and then with increasing Displacement path increasingly;
  • the length and cross section of the ram are So matched so that the plunger with the pilot channel of the main piston a very small throttle gap at the start of opening of the pilot piston forms, the throttling effect much greater than the throttling effect is the compensating throttle and then until the minimum cross-section is reached forms a steadily increasing throttle gap, the Throttling effect with the movement length of the pilot tappet and Control piston steadily and preferably decreases more and more, so that the Remove the closing forces acting on the main piston.
  • This is through the special design of the throttle area with regard to its length and reached its cross section.
  • the cross section starts from the maximum cross section and then takes over its length to the minimum cross section steadily.
  • the decreasing throttling effect achieves that the throttle gap of the pilot tappet relative to the pilot channel wall, starting from the throttle gap of the maximum cross section, steadily increasing.
  • the cross section also starts from the maximum cross section out; he then takes over a first part length except for one Cross-section that is larger than the minimum cross-section; about another This cross section remains the same for part of the length.
  • the decreasing Throttling effect achieved in that the immersed in the pilot channel Length of the throttle gap of the pilot tappet with displacement of the pilot tappet is steadily decreasing. Combinations of both versions are also conceivable.
  • the constant reduction in the cross section of the tappet in the throttle area d. h .: the decrease in the throttling effect of the tappet compared to the pilot channel can e.g. can be achieved in that the plunger in the area with a reduced cross-section is a rotary body whose diameter changes Slightly conical over its length or - preferably - progressive, i.e. parabolically or hyperbolically reduced.
  • the length of the throttle region is preferably based on the change in the the closing piston acting on the main piston.
  • These closing forces are composed of the hydraulic forces and those on the Main piston acting spring forces.
  • the pressure reduction in the pilot control room takes place continuously and in a defined manner Dependence on the control pressure and the resulting movement of the The opening piston. It is avoided that the main piston is the pilot piston hurries ahead or uncontrolled and uncontrollable movements performs.
  • a precisely working hydraulic follow-up system is created. Once the Load pressure is released behind the main piston, the main piston follows automatically the pilot piston, since the load pressure on the resulting Annular surface of the main piston acts, the main piston from its valve seat pushes. Because the main piston is the pilot piston displaced by the pilot piston follows, the opening cross-section becomes in the pilot valve seat again narrow so that there is again a back pressure in the pilot room of the main piston. This creates an equilibrium position between the control piston and the pilot piston on the one hand and the main piston on the other hand.
  • the advantage of this principle is that the closing direction acting flow force through the hydraulic power amplification achieved is less than the hydraulic opening force under all conditions. This prevents pressure fluctuations in the consumer connection B trigger unwanted movements of the main piston. This can do that A boom on the hydraulic excavator or crane is prevented from rocking become.
  • the maximum cross section of the pilot tappet is relative to that Cross-section of the pilot channel designed so that the throttle cross-section after opening the pilot valve seat is initially only insignificantly smaller than the throttle cross section of the compensating throttle, so that when lifting the Main piston from the seat a slow pressure reduction in the pilot room can take place.
  • the load holding brake valve integrates the functions for holding, lowering, lifting and securing loads in one valve housing with a very compact design. It is achieved that at accordingly designed course of the throttle cross-section constantly a hydraulic Force acts on the pilot piston so that this or the tappet itself cannot lift off the control piston, despite the pressure drop on the Spring side of the pilot piston.
  • the spring-loaded main piston In the load lifting state, the spring-loaded main piston also takes over Function of a check valve.
  • the small opening pressure of the Check valve made possible by a large seat.
  • the big one Area ratio between the effective diameter of the valve seat and the Effective diameter of the pilot valve seat is reached that the pilot piston does not open.
  • the invention allows a fine gradation of the various throttling points, which are formed or are present in the valve.
  • the control pressure is largely independent of the load pressure to be controlled, so that even with low Control pressure allows a wide control range and sensitive control becomes.
  • the training according to claim 1 ensures that the control with a low control pressure, the valve reacts and a Movement of the load leads.
  • the embodiment according to claim 1 serves to increase the closing effect.
  • two springs are preferably provided in parallel can be.
  • One of these springs can only be used on the main spool act, but the other on the pilot spool and thus indirectly also on the main piston. It is advantageous because of the sensitive pilot control of the main piston also possible, only the pilot piston to load with a spring in the closing direction, which at the same time also acts on the main piston in the closing direction.
  • the cross-section of the pre-throttle bore can be greater than / equal to or smaller than the flow cross-section of the compensating throttle between the pilot room and annulus.
  • the embodiment according to claim 3 is advantageous if the control pressure is specified regardless of the inlet pressure.
  • grading the Pilot piston and the pilot throttle is brought about that a higher closing pressure acts on the pilot piston.
  • the flow can be reduced be reduced from B to A with increasing load pressure.
  • the reaction of the The valve is damped so that there are discontinuities or vibrations Stress or discontinuities in the control in particular not as Vibrations of the valve can affect.
  • pilot piston and the pilot piston are independent misaligned, misalignments remain between the control piston and the pilot spool with no effect.
  • the opening pressure of the pressure relief valve is also independent from the return pressure. This principle of the pressure relief valve is achieved that with a downstream pressure relief valve in the directional control valve there is no summation of the set pressures.
  • the load holding and braking valve according to this invention has - as already executed - a control piston with which the actuation of the pilot piston hydraulically and mechanically.
  • Such hydraulic-mechanical actuation of valves comes in hydraulics many times before, e.g. B. in the hydraulic actuation of control valves.
  • This hydraulic control has the disadvantage that the opening of the Control valve for a - more or less fast - growth of the Control oil quantity leads. It therefore depends on the attention and Dexterity of the operator from that the control valve on reaching a desired drive oil quantity, d. H. when a certain one is reached Position of the hydraulic-mechanically controlled valve, the To keep the control valve in this position.
  • Another object of this invention is this, like any other hydraulic-mechanical controlled valve, in a predetermined end position bring. Such an embodiment results from claim 7.
  • Such metering valves can be based on a hydraulic principle of action, z. B. by metering predetermined amounts of oil, which then as the control oil Control piston are supplied.
  • the closing element can be mechanically connected to the Control piston be contacted so that when reaching a predetermined Position of the control piston the supply of another control oil flow is interrupted.
  • a hydraulically and mechanically advantageous integration of the metering valve in the control device results from claim 9.
  • Claim 14 gives a simple way of relieving the pressure Closing element.
  • Claim 15 describes further execution options.
  • the stroke limitation very often does not represent the desired end position of the Control piston and the valve actuated thereby represent only one Position from which the end position is to be approached. This is especially when lowering loads. There is said to be the essential The route is traversed at high speed, while the end position is slow, d. H. is started in slow speed.
  • Claim 16 forms the valve according to claims 7 to 15 accordingly out.
  • the fast mode can be switched on very suddenly the valve in the open state of the metering valve is operated.
  • an operation in creep speed via damping nozzles which is an adjustment allow the speed of the creep speed.
  • the now damped operation of the control piston allows the desired end position to start up by fine control.
  • the ratio of the overdrive range to slow speed (fine control range) can be set from the outside by adjusting the Adjustment spindle for the metering valve can be set.
  • the quick response of the control piston remains possible despite the strong hydraulic damping.
  • a preload valve is provided, which when a certain control pressure is exceeded, the connection of the control pressure channel to the control chamber and control piston opens (claim 17).
  • the training according to claim 18 serves the purpose of pressure vibrations the control pressure both in fast mode and in fine control mode dampen.
  • Fig. 1 is the hydraulic circuit diagram of a control of a consumer in the sense of adapting an outflow to an inflow by means of a load holding brake valve shown.
  • the consumer 26 is on the feed line 28 and the lower line 25 connected.
  • the lower line 25 is connected to port B of the load holding brake valve 1A.
  • From the load holding brake valve 1A leads a return line 27 from port A to the Directional control valve 31.
  • the inlet line 28 also connects to the directional control valve 31.
  • the Directional valve 31 is designed as a 4-3-way valve.
  • the inlet pipe 28 and the return line 27 is the connection of a pump 32 and the connection of a line to the tank 33 is provided.
  • the load holding brake valve 1A is connected to the feed line 28 via a control line 29.
  • the pump 32 connected to the return line 27.
  • the inlet line 28 is also available the tank 33 in communication so that on the control side of the load holding brake valve 1A no pressure is applied and the load holding brake valve 1A in the position shown persists.
  • the consumer is in this position 26 in lifting operation.
  • the pump volume flow passes through the Return line 27 and the check valve in the load holding brake valve 1A to connection B. From there, the oil flows through the lowering line 25 to Consumer 26.
  • the pressure relief valve 30 serves to secure the load pressure in the Lowering operation or standstill of the consumer and is between the lowering line 25 and the return line 27 are arranged.
  • An additional pressure protection is usually arranged on the directional control valve (not shown here).
  • the cylindrical control chamber 2 is at the end by means of a control chamber plug 13 closed.
  • the connection holes A and B In the control chamber 2 open perpendicular to the longitudinal axis the control chamber 2, the connection holes A and B.
  • a valve seat 5 Between the Connection bores A and B have the control chamber 2 a valve seat 5 on.
  • the valve seat 5 is fixedly attached to the valve housing 1 and separates the annular space 70 from the return space 73.
  • a Main piston 3 guided.
  • the main piston 3 has a thinner one Collar with a conical sealing surface 4, which cooperates with the valve seat 5.
  • the main piston 3 On the side facing away from the valve seat 5 and the connection bore B facing side, the main piston 3 has an end collar 42 on.
  • the end collar 42 has a larger diameter than the above Bund and is sealingly guided in the control chamber 2, so that the main piston 3 is axially movable.
  • the main piston 3 By training as a stepped piston the main piston 3, the annular space 70, with the lowering line 25 via connection B is connected.
  • the annular space 70 is by lifting the main piston 3 of the valve seat 5 with the return chamber, the connection B and the tank 33 connected.
  • the area of the control chamber 2 between the thick end collar 42 of the The main piston 3 and the control chamber plug 13 is the pilot control chamber 15 designated.
  • This pilot control chamber 15 serves to receive a spring 12A (not shown) between the control chamber plug 13 and the main piston 3 is clamped.
  • Spring 12 One is shown - to be described later Spring 12 - which has the same function so far, so that the main piston 3rd by spring force, but also by the hydraulic acting on it Forces on valve seat 5 is pressed.
  • the annular space 70 is connected to the pilot space 15 via the throttle 14.
  • the throttle 14 can - as shown - axially parallel in the thicker Piston collar can be arranged, but also in the valve housing.
  • the main piston 3 is penetrated concentrically by a pilot channel 34, that connects the pilot room 15 to the return chamber 73.
  • the main piston 3 has a concentric with respect to the pilot chamber 15 arranged step bore 71. From the bottom 72 of the first step with Larger diameter goes with the stage designated as pilot channel 34 smaller diameter. On the bottom 72 between level 71 and the pilot valve seat 6, the pilot valve seat 6 is formed.
  • pilot piston 8 is with its piston shaft, the pilot piston 9, guided in the pilot channel 34 with play.
  • pilot piston 8 and pilot ram 9 are made from one or two pieces.
  • the Pilot tappet 9 has a smaller diameter than that from the Pilot channel 34 projecting pilot piston 8.
  • the pilot piston 8 has at its end, which is connected to the pilot tappet 9, a sealing surface 7, under the force of the pilot spring 12 (closing spring) on the Pilot valve seat 6 is located.
  • the smaller truncated cone surface corresponds essentially the cross section of the pilot channel 34 and the subsequent Area of the pilot tappet 9.
  • the pilot tappet 9 has several diameter ranges over its length or cross-sectional areas.
  • a small groove adjoins the conical seat as an undercut.
  • the Groove runs in the circumferential direction and has essentially manufacturing technology Reasons.
  • a very short area of large cross section ( Cross-sectional area) of the pilot piston 8. This area is cylindrical trained and with little play has a diameter that the diameter of the pilot channel 34 and the smaller sealing surface 7 corresponds. Its length can go to zero, so that it is only the beginning of the represents the following range.
  • An area is attached to the very short area of large cross-section with decreasing throttling effect.
  • the one that decreases with the tappet movement Throttling effect is achieved in that the cross section of this Area - based on the maximum cross-section - at least over one Partial length steadily decreased and / or that the piece of this partial length that in the pilot channel is immersed, when the pilot tappet is moved shortened. Another part of this range can be constant Have a cross section, which is however larger than the cross section of the then following area with the smallest cross-section.
  • the decreasing throttling effect results from the fact that with the tappet movement the area first with a decreasing cross-section from the pilot channel to the pilot room shows up.
  • the area can be cylindrical with the diameter of the previous one Form the area and chamfer or on the cylinder jacket Make grooves that start from the largest cross section and on the smaller, constant cross-section. Fluidic and Production-technically favorable versions of the area with decreasing Cross sections are described with reference to Figures 3a and 3b.
  • the end of the pilot tappet 9 (piston skirt) has a smallest Cross section, which is essentially the smallest cross section of the area corresponds to decreasing cross-section. This end range is only too a part within the pilot channel 34. It extends over the length of the Pilot channel 34 and protrudes with its end in the return chamber 73 of the control chamber 2.
  • the pilot tappet 9 points after the Sealing surface 7 on a circumferential undercut groove 35. That includes itself cylindrical area, whose diameter with play the diameter of the pilot channel corresponds to (area with the largest cross section, area with Maximum cross section).
  • the "area 143 begins at a short distance from the undercut decreasing throttling effect ".
  • the entire region 143 can have a decreasing Have cross-section and as a rotating body with a straight or preferably parabolic or hyperbolic surface line.
  • Fig. 3a the decreasing throttling effect of area 143 on the first part length 144 through a decreasing cross section of the ram reached.
  • the ram is weakly tapered on this part length, i. neck Truncated cone.
  • the large cone area corresponds to the cross section of the previous area with the largest cross section.
  • the small cone area corresponds to the cross section of the subsequent partial length 145, the one has a constant cross-section.
  • This partial length 145 calls in the pilot channel only a small throttling effect that emerges with the appearance this part length decreases steadily from the pilot channel.
  • This part length is therefore only of minor importance for the function of the valve. Their length can therefore go to zero.
  • Partial length 145 with a constant cross section is included Area 146 with the smallest cross section. It should be emphasized that this is the smallest Cross section is in any case smaller than the cross section of the previous one Part length 145 with constant cross section. The boundary between the two Cross-sectional areas is in any case with the pilot valve closed the pilot channel. The area with the smallest cross section protrudes from the Pilot channel out into the return space.
  • the embodiment of the pilot tappet 9 shown in FIG. 3b has in the Area with decreasing throttle effect in the axial direction several throttle grooves 10 on that with the wall of the pilot channel 34, the throttle point 36 form.
  • the throttle grooves 10 have a decreasing range Cross-section steadily towards the free end of the pilot tappet 9 and - preferably progressive - increasing depth (partial length with decreasing Cross-section). Then they maintain the maximum depth reached (Partial length with constant cross-section).
  • Following the area with the throttle grooves 10 (area with decreasing throttling effect) follows here also the area with the smallest cross-section. This area is again cylindrical.
  • the diameter can essentially that Correspond to the diameter of the deepest groove base of the throttle grooves 10.
  • the throttle grooves 10 can by flats or notches that are introduced axially or helically on the pilot tappet 9, replaced become. Instead of or next to the depth, the width of the throttle grooves 10 to be changed. This is especially true in the initial area of the grooves, i. h .: in the area with decreasing throttling effect.
  • the throttling effect is now from the area with decreasing throttling, i.e. h .: first by the decreasing cross section of the pilot tappet emerging from the pilot channel 34 9 determined.
  • the depth of the throttle grooves increases (Fig. 3b) or the diameter of the ram (Fig. 3a).
  • the throttling effect When this part length (truncated cone or grooves) appears, the Pilot channel 34 in the pilot room steadily lower.
  • a separating web 17 separates the return space 73 from that axially aligned control bore 43.
  • the control bore 43 is on the other End face closed by the plug 22.
  • a control piston 20 (guide collar) sealingly guided.
  • the control piston 20 divides the control bore 43 into the control chamber 21 and the the separator 17 adjacent spring chamber.
  • the plug 22 has a connection bore X on, through which the control chamber 21 with the control line 29 (Fig. 1) is connected.
  • the control piston 20 has a control shaft 16, 19 which consists of a thicker part 19 and consists of a thinner part 16.
  • the thinner part 16 of the control shaft penetrates the separating web 17 and is in the Separator in the guide bore 74 sealing (seal 18 or a sealing gap) guided.
  • the free end of the control shaft 19 with the end face 44 protrudes into the return chamber 73, the control shaft 16, 19 and the pilot tappet 9 of the pilot piston 8 lie on an axis line.
  • the control piston 20 is formed by a control spring designed as a compression spring 24, which is arranged in the spring chamber 43 and on the Supported divider, pressed into its starting position when no control pressure rests in the control chamber 21.
  • the spring chamber 43 is by means of Leakage oil hole L relieved of pressure.
  • the control spring 24 by one or more springs 46, 47 connected in parallel (see Fig. 4) formed.
  • the thicker area 19 of the control shaft 19 forms compared to thinner area 16 an end face 48.
  • This end face serves as a stop surface 48 for mechanical stroke limitation of the control piston 20, by reaching the system with the separating web 17.
  • the guide collar of the control piston 20 one with one Control pressure acted on end face 45, the effective surface for Effective area of the pilot valve seat 6 in a ratio of greater than 50: 1, preferably greater than 100: 1.
  • the ratio of the end face 45 on the guide collar to the end face 44 at the control end 16 is greater than 30: 1, in particular greater than 60: 1.
  • control pressure remains largely independent of the load pressure.
  • control pressure also remains largely independent of the return pressure.
  • the pressure relief of the spring chamber 43 in the area of the control spring 24 thus enables a precisely predetermined and from Structure of the control pressure-dependent force curve on the control piston 20 acts.
  • the course of the throttle cross-section on the pilot tappet is designed such that that an impressed by the control piston 20 displacement movement of the Pilot piston 8 in the opening direction only with increasing hydraulic Force on the control piston 20 for lifting operation is possible.
  • the ratio of the effective areas of the main piston 3 and pilot piston 8 is designed in such a way that no relative movement between the main piston 3 and pilot piston 8 in the sense of an opening of the pilot valve seat 6 is executable.
  • connection bore B and the annular space 70 is the load pressure of the Consumer.
  • the pilot control chamber 15 is connected to the throttle 14 Annulus 70 connected.
  • the load pressure acts on the effective area of the thicker one End collar 42 of the main piston 3.
  • the main piston 3 with its Sealing surface 4 is by the spring 12 and hydraulically against the valve seat 5 pressed.
  • the pilot piston 8 is with the load pressure and the spring force of the spring 12 acted upon; it is with its sealing surface 7 on the pilot valve seat 6 held. The connection from B to A is thus blocked leak-free.
  • the directional control valve 31 (FIG. 1) connects the consumer 26 via the inlet 28 with the pump and via return line 27 with the tank.
  • the load holding brake valve is via the control line 29 and connection hole X via Inlet 28 connected to the pump.
  • the one that can be changed by the directional valve Pressure acts as a control pressure on the control piston 20.
  • the control pressure accordingly, the control piston 20 against the control spring 24th moved to the separating web 17 until the spring force and opening force in Are balance.
  • the control shaft 16 abuts with its end face 44 to the free end of the pilot plunger 9 of the pilot piston 8 and shifts the pilot ram 9 - in absolute terms - by a distance, that is proportional to the pilot pressure.
  • the sealing surface 7 of the pilot piston 8 is lifted out of the pilot valve seat 6.
  • the movement of the main piston 3 in the sense of opening the main valve seat means relative to the pilot piston and plunger 9 a movement in the sense of closing of the pilot valve 6/7, because the absolute position of the pilot valve 9 by the position of the control piston 20 is predetermined. Since the main piston 3 the pilot piston 8 follows in its movement, so the throttle cross section narrow again at the throttle point 36 in the pilot channel 34. As a result, a higher pressure builds up again in the pilot control chamber 15. This pressure build-up ensures that between the pilot piston 8 and the main piston 3 is set to an equilibrium state.
  • the length and throttling effect of the throttle area of the pilot tappet 9 are matched to the spring and hydraulic forces on the main piston 3. Every movement of the control piston 20 and the pilot piston 8 and pilot plunger 9, the main piston 3 follows immediately and evenly.
  • the design of the main piston 3 in connection with the valve seat 5 also has the advantage that the flow forces acting in the closing direction always counteracts a hydraulic opening force that in everyone Position is greater than the flow forces. With that, the impact possible pressure vibrations in port B on the main piston 3 avoided.
  • control piston 20 Since the control piston 20 is in relation to the pilot valve seat 6 has a large effective area, the pilot pressure is essentially independent from the load pressure.
  • the ratio between the effective area of the control piston 20 to the effective area of the pilot valve seat is greater than 50: 1, preferably greater than 100: 1.
  • the control piston 20 has Ratio of its end faces 45 and 44, which is preferably greater than 30: 1 is. This means that the pilot pressure is largely independent of the return pressure.
  • connection A As can be seen in FIG. 1, with the pump 32 connected.
  • the pump pressure stings in the return chamber 73 at the valve seat 5, and lifts the main piston 3 against the spring force (spring 12 and possibly Spring 12A) and opens valve seat 5.
  • the load is lifted. by virtue of the large difference between the effective area of the valve seat 5 and the The effective area of the pilot valve seat 6 will increase with this check valve function the main piston 3 move together with the pilot piston 8. Due to the large area of the valve seat 4 on the main piston 3 arise only minor throttling losses at the valve seat.
  • the compensating throttle 14 and the pre-throttle bore 41 also through Nozzles can be replaced so that a pressure-independent pressure reduction can be done.
  • a pressure relief valve for load securing can be placed in the load holding brake valve to get integrated. This is shown and described with reference to FIG. 4.
  • the pilot piston 8 and the main piston 3 advantageously clamped only with the spring 12, the supports the valve housing.
  • the main piston 3 is essentially by hydraulic forces moved axially.
  • the pilot piston 8 has this Execution of a guide shaft 37 which in the stepped bore 71 of the Main piston 3 is guided sealingly. This forms between the pilot valve seat 6 and guide shaft 37 concentrically to the control piston 8 Anteroom 40 to the pilot room 15.
  • the antechamber 40 is a Pre-throttle 41 connected to the pilot room 15.
  • the throttle cross section the pre-throttle 41 can be larger, equal to or smaller than the throttle cross-section the compensation choke 14 may be executed.
  • This configuration of the Pilot piston 8 has the advantage that the pressure reduction in the pilot chamber 15 takes place over two stages, which have a fixed throttle cross section exhibit.
  • the pre-throttling hole is particularly effective when open 41 that a higher closing force on the Pilot piston 8 acts.
  • the higher closing force leads to the axial displacement of the throttle cross-section in the pilot channel (throttle point 36 in FIG. 3) is also reduced in size and thus the main piston 3 increasingly closes due to the overrun regulation.
  • This system is special an advantage in an open circuit.
  • control piston 20 Due to the large area of the control piston 20 can in the control bore (Spring chamber) 43 as a control spring two connected in parallel preloaded springs 46 and 47 between the guide collar 20 and the Separator 17 can be clamped. If one spring breaks, the other is The spring is able to close the pilot piston in its starting position move. This is of particular importance in terms of security.
  • a blind hole 50 is introduced at the end.
  • the blind hole is 50 by means of overload bore 49 with the annular space (load chamber) 70 and over the Return bore 60 connected to the return chamber 73.
  • the plug 51 (socket) is screwed in.
  • an inner bore 52 is made in the center, towards the blind hole is open and forms the check valve seat 54 with its end.
  • the Check valve seat 54 is between the overload bore 49 and the Return bore 60.
  • Inner bore 52 is via radial bores 53 and a recess 76 on the plug 51 with the overload chamber 49 connected.
  • the overload chamber 49 and the return chamber 60 are between the bore 68 and the inner bore 52 of the valve housing Pressure relief valve 30 arranged.
  • the spring-loaded pressure limiting piston 55 of the pressure relief valve 30 has a sealing surface 56, that under the biasing force of a compression spring 57, 66 on the check valve seat 54 rests and the radial bore 53 with respect to the return space 73 seals.
  • the pressure limiting piston 55 has on both sides an end collar 62, 63.
  • the piston shaft penetrates the radial bore 53 and has an end collar 62 at its end. This end collar is 62 in the inner bore 52 sealingly (seal 79), the end face 64 is slightly smaller than the cross section of the check valve seat 54 of the piston.
  • the end collar 63 attaches to the pressure limiting piston 55 and is - With a tapered end part - in the front wall and guide hole 77 guided with seal 61 and protrudes into the bore 68.
  • the inner bore 52 which is adjacent to the overload bore 49 and its end collar 62 are with the pressure of the return chamber 73 loaded.
  • a relief channel is used for this 81, which is designed as a longitudinal bore in the axis of the piston and the the return chamber 73 through a radial branch channel 80 with the end space connects at end collar 62.
  • the cross section of this end space as well as the End collar 62 is slightly smaller than the seat 54 of the check valve seat 54.
  • the effective area, which acts in the opening direction at load pressure is this difference.
  • the bore 68 is for pressure relief through the relief bore 69 with the control bore 43 (spring chamber) and the leak oil hole L.
  • the one protruding into hole 68 thinner end collar 63 is in terms of its hydraulically effective cross section (Face 65) the same size as the above. Effective area in the opening direction, d. that is, the difference between the valve seat surface 54 and the cross section the inner bore 52 with end collar 62.
  • the piston 55 of the pressure relief valve 30 is connected in parallel with two Compression springs loaded in the closing direction; which is a compression spring 57 in the return chamber against the piston shoulder 58 and the other compression spring 66 in the pressure-relieved end chamber against the piston skirt with end collar 63 clamped.
  • the plug is used to adjust the load securing pressure 51 screwed more or less deep into the blind hole.
  • the load pressure is in the inner bore 52 against the sealing surface 56 of the Valve seat 56 on.
  • the pressure-limiting piston 55 becomes axial against the springs 57 and 66 postponed.
  • the sealing surface 56 rises from the check valve seat 54, and the pressure relief valve 30 opens.
  • the oil can now drain from the overload hole 49 via the opened valve seat 54 to the return bore 60 stream.
  • the limit value (load securing pressure) is connected in parallel by the two Compression springs 66 and 57 specified.
  • the design of the pressure limiting piston 55 and its pressure relief has the consequence that the opening pressure in the inner bore 52nd acts on the valve seat 54, regardless of the return pressure and exclusively depends on the load pressure.
  • This embodiment of a pressure relief valve is particularly important for the load securing function in the load holding brake valve suitable. Because in the usual circuits a downstream one If there is a pressure relief valve in the directional control valve, this occurs not to add up the set pressures.
  • FIGS. 1 to 4 show a possibility of hydraulic stroke limitation of a pilot operated valve.
  • This hydraulic stroke limitation lets apply to all hydraulically pilot operated valves where a Control valve for actuating a valve piston is provided.
  • the hydraulic Stroke limitation is illustrated on a load holding brake valve; how it is labeled in Figures 1 to 4.
  • 5 is the circuit diagram Similar to the circuit diagram of FIG. 1. On the description of FIGS. 1 to 4 full reference is made.
  • the pressure relief valve 30 after 3, 4 is not shown here.
  • the load holding brake valve is added through a metering valve 84 in the control of the control piston 20 the control connection X.
  • a metering valve 84 is used for this control.
  • the metering valve 84 is in Details are shown in FIG. 6 and will be described with reference to FIG. 6.
  • the metering valve 84 is located in the cover 22, which is the control chamber 21 limited.
  • the cover 22 is on the valve housing 1 of the load holding brake valve flanged pressure-tight by means of seal 121.
  • the dosing chamber with valve seat 109 of the metering valve 84 is relative to the control chamber 21 movably guided and positionable.
  • the Valve seat 109 of metering valve 84 formed on a closing piston 119, which dic dosing valve chamber 102 compared to the control chamber 21 in other closures and which in the metering valve chamber 102 parallel to the pilot piston is sealingly guided and positionable.
  • a longitudinal bore 104, 105 in the cover 22 which is coaxial to the valve axis of the load holding brake valve.
  • This longitudinal bore is on hers End, which faces away from the load holding brake valve, with a Thread 105 provided.
  • link level 104 On their remaining length (link level 104) has a larger diameter.
  • An adjustment spindle is in the thread 105 106 screwed in and pressure-tight with a counter sealing nut 113 braced.
  • the adjusting spindle 106 forms with the longitudinal bore 104, 105 an annular space in the area of connection stage 104. In this connection stage 104 opens the tax line.
  • In the control line X is a filter 116 and a nozzle 117 turned on.
  • the annulus is on the Side facing the load holding brake valve by a guide collar 119 completed, which is firmly connected to the end of the adjusting spindle 106 and which in the guide step 103 of the longitudinal bore 102 by means of O-ring seals 120 is performed sealingly.
  • the adjusting spindle 106 is penetrated centrally by a central channel 108.
  • Das Closing element 110 is a ball here.
  • the shaft 118 is supported on the one hand on the closing element 110 and is preferably with a control piston 20 firmly connected.
  • the stem 118 also penetrates the valve opening channel 107 big game and protrudes into the control chamber 21, where it is at the front of the control piston 20, which the control chamber 21 to the other Side limited, is present.
  • the central channel 108 forms with the diameter smaller valve opening channel 107 a conical or dome-shaped annular valve seat 109, on which the closing element 110 fits.
  • the closing element 110 is guided with play in the central channel 108. It is so by a spring 111 in the direction of the control piston 20 pressed that it is over the shaft 118 on the front side of the control piston 20 supports.
  • control connection x If the control connection x is subjected to control pressure, then plants the control pressure in the connection stage 104 and the radial channel 114 to the central channel 108. Since the closing element 110 compared to the Walls of the central channel 108 has great play, the control pressure is too high both sides of the closing element 110. The oil flow then passes through Valve opening 107 into the control chamber 21.
  • the closing element 110 and the shaft 118 of the closing element are pressed by the spring 111 in the direction of the control piston 20, so that shaft 118 and closing element 110 the opening movement of the opening piston participate.
  • the closing element 110 which is shown here as Ball is formed at the end of the central channel 108 and to the system to the valve seat 109 of the valve opening. This will open the valve 107 closed and the opening movement of the opening piston 20 completed.
  • metering valve by itself, but also in combination with one or more elements a, b and c also for other control tasks can be used which involve a control piston, by which a hydraulic flow is controlled, by a control pressure hydraulically controlled and adjusted, especially against the To be adjusted by means of a return spring.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Safety Valves (AREA)
  • Fluid-Driven Valves (AREA)

Claims (18)

  1. Soupape de frein à maintien de charge pouvant être commandée de manière hydraulique, en particulier pour un consommateur à double effet, dont le côté charge est soumis unilatéralement à une charge extérieure, avec les caractéristiques suivantes :
    dans un boítier de soupape (1) est disposée une chambre de commande (2) ;
    la chambre de commande se compose de sections de chambre disposées de préférence en alignement, et ceci dans l'ordre suivant :
    compartiment de commande pilote (15) ;
    compartiment annulaire (70) relié par le raccord B avec la conduite descendante (25) du consommateur (26);
    compartiment de retour (73) relié par le raccord A avec la conduite de retour (27) vers le réservoir ;
    compartiment de commande (21) ou de commande de progression, relié avec un canal de commande (X) ;
    un siège de soupape (5) avec un passage central, qui permet de relier les forures de raccordement A et B, est disposé de manière fixe sur le boítier de soupape (1) dans la chambre de commande (2) entre le compartiment circulaire et le compartiment de retour ;
    le siège de soupape est fermé ou ouvert par un piston principal (3) ;
    le piston principal (3) est réalisé comme piston à paliers et comprend :
    une collerette de piston mince, qui constitue avec la paroi cylindrique de la chambre de commande (2) le compartiment annulaire (70) et une surface d'étanchéité (4) se trouvant sur la collerette de piston mince, qui est dirigée vers le siège de soupape et qui est en interaction avec le siège de piston (5) et
    une collerette de piston épaisse, qui est guidée de manière à assurer une étanchéité sur la paroi de la chambre de commande entre le compartiment annulaire et le compartiment de commande pilote et qui les sépare l'un de l'autre ;
    le piston principal peut coulisser dans le sens axial dans la chambre de commande (2), et ceci au moyen d'une application de pression dans la chambre de retour (73) ou dans le compartiment annulaire (70) pour son décollement du siège de soupape (5) et au moyen d'une application de pression dans le compartiment de commande pilote (15) pour la fermeture du siège de soupape ;
    le compartiment de commande pilote (15) peut être relié par l'intermédiaire d'un élément d'étranglement de compensation (14) au compartiment annulaire (70) ainsi qu'au raccord B et par l'intermédiaire d'un canal de commande pilote (34), comprenant un siège de soupape de commande pilote (6) dans le piston principal (3), au compartiment de retour (73) ainsi qu'au raccord A ;
    le canal de commande pilote avec un siège de soupape de commande pilote (6) peut être fermé par un élément de fermeture guidé de manière concentrique par rapport au canal de commande pilote (34), le piston de commande pilote (8) avec sa surface d'étanchéité (7) par une application de pression dans le compartiment de commande pilote (15) et de préférence par la force d'un ressort de fermeture, et être ouvert dans le sens opposé par un poussoir de commande pilote (9), lequel poussoir de commande pilote (9) est guidé avec du jeu dans le canal de commande pilote (34) et pénètre dans le compartiment de retour (73) ;
    un piston de commande ou de commande de progression (20) est guidé dans le sens axial dans le compartiment de commande (21) et peut être déplacé par une application de pression dans le compartiment de commande (21) en direction du compartiment de retour (73) et par un ressort de commande ou de commande de progression (24) dans le sens opposé;
    le piston de commande (20) comprend une tige de commande (19) dirigée contre le poussoir de commande pilote (9) et alignée dans le sens coaxial par rapport à celui-ci, dont une extrémité, c'est à dire l'extrémité de commande ou de commande de progression (16), pénètre dans la chambre de commande (2) en agissant, dans le cas d'un déplacement axial du piston de commande (20), contre la force du ressort de commande (24) sur le poussoir de commande pilote (9) et le piston de commande pilote (8) dans le sens de l'ouverture, caractérisée
    en ce que le poussoir de commande pilote (9) comprend sur sa longueur et en partant de la surface d'appui (7) du poussoir de commande pilote (8) au moins les zones de longueurs suivantes :
    d'abord une zone à section maximale (142), qui est guidée avec le jeu le plus faible par rapport au canal de commande pilote (34),
    ensuite une zone d'étranglement (143) qui s'y rattache et qui forme sur sa longueur et avec sa section par rapport au canal de commande pilote (34) une fente d'étranglement, qui part de la fente d'étranglement de la section maximale et qui s'accroít ensuite constamment, de préférence progressivement, au moins sur une longueur partielle (144) de la zone d'étranglement (143) ;
    enfin une zone (146) à section minimale ;
    en ce que le poussoir de commande pilote (9) est de préférence relié de manière fixe au piston de commande pilote (8) ;
    en ce que le rapport entre la surface active (45) du piston de commande (20) soumise à la pression de commande et la surface active du siège de soupape de commande pilote (6) est supérieur à 50 : 1, de préférence supérieur à 100 : 1 et en ce que de préférence le rapport entre la surface frontale (45) du piston de commande (20) et la surface frontale (44), respectivement la surface active (74), à l'extrémité de commande (16) est supérieur à 30 : 1, en particulier supérieur à 60 : 1 ;
    en ce que la section d'étranglement (36) que forme le poussoir de commande pilote (9) avec le canal de commande pilote (34) est, dans toutes les positions d'ouverture du piston de commande pilote (8), plus petite que la section d'ouverture formée entre le siège de soupape de commande pilote (6) et la surface d'étanchéité (7) du piston de commande pilote (8) et
    en ce que la section maximale d'étranglement que forme le piston de commande pilote (8) avec le canal de commande pilote (34) est plus grande que la section de passage du flux de l'élément d'étranglement de compensation (14).
  2. Soupape selon la revendication 1, caractérisée en ce que dans la zone d'étranglement, qui est la plus proche du piston de commande pilote, le poussoir de commande pilote (9) est de forme cylindrique et comprend sensiblement la section maximale et un jeu faible par rapport au canal de commande pilote (34), en ce que dans la zone d'étranglement (143) à effet d'étranglement décroissant qui suit après, le poussoir de commande pilote (9) comprend sur son enveloppe au moins une rainure d'étranglement (10) dirigée dans le sens axial, dont la profondeur et/ou la largeur arrive à la zone à section maximale avec une valeur qui est sensiblement égale à zéro et s'accroít constamment sur une longueur partielle (144) de la zone d'étranglement (143) et qui, de préférence - se poursuit ensuite de manière constante sur une autre longueur partielle (145) et de préférence en ce qu'à l'autre extrémité de la zone d'étranglement (143) le fond de rainure des rainures d'étranglement se termine sensiblement au niveau de la section minimale du poussoir de commande pilote (9).
  3. Soupape selon l'une des revendications 1 ou 2, caractérisée en ce qu'à son extrémité dirigée vers le compartiment de commande pilote (15) le piston principal (3) comprend une forure de guidage centrale (38), du fond de laquelle part le canal de commande pilote (34), en ce qu'à l'extrémité dirigée vers le compartiment de commande pilote le piston de commande pilote (8) comprend une tige de guidage (37), qui est guidée de manière à assurer une étanchéité dans la forure de guidage (38) dans le piston principal (3) et comprend une surface frontale (39) plus importante par comparaison avec la surface active du siège de soupape de commande pilote (6), et en ce que la partie de la forure de guidage (38), qui se trouve entre le siège de soupape de commande pilote (6) et la tige de guidage (37), est reliée au compartiment de commande pilote (15) par l'intermédiaire d'une forure d'étranglement primaire (41).
  4. Soupape selon l'une des revendications 1 à 3, caractérisée en ce que le compartiment annulaire (70), y compris le raccord B et la conduite descendante (25), et la chambre de retour (60) avec le compartiment de retour (73), y compris le raccord A, la conduite de retour (27) et le réservoir, sont reliés par l'intermédiaire d'une chambre (49), d'une chambre de retour (60) et d'un piston de limitation de pression (55) d'une soupape de limitation de pression (30), qui est disposé entre, et qui est soumis à une action de ressort.
  5. Soupape selon la revendication 4, caractérisée en ce que la chambre (49) et la chambre de retour (60) se trouvent entre deux chambres d'extrémité de la soupape de limitation de pression (30), en ce que le piston de limitation de pression (55) soumis à une action de ressort de la soupape de limitation de pression (30) comprend une surface d'étanchéité (56) ainsi qu'aux deux extrémités respectivement une tige de piston avec une extrémité de guidage (62) et une extrémité de guidage (63), la surface d'étanchéité (56) étant appliquée sur le siège de soupape (54) sous la précontrainte d'un ressort de compression (57) et chaque extrémité de guidage (62, 63) étant guidée de manière à assurer une étanchéité dans une des chambres d'extrémité du boítier de soupape (1), en ce que la chambre d'extrémité, qui est voisine de la forure de surcharge (49), ainsi que son extrémité de guidage (62) sont soumises à la pression du compartiment de retour (73) par l'intermédiaire de la forure longitudinale (81) et de la forure transversale (80) et comprend une section (64) qui est légèrement inférieure à la surface du siège de soupape et en ce que la chambre d'extrémité comprenant l'extrémité de guidage (63) est déchargée en pression et a, en ce qui concerne sa section active au niveau hydraulique (65), la même taille que la différence entre la surface du siège de soupape (54) et la section (64) de la chambre d'extrémité (147) comprenant l'extrémité de guidage (62).
  6. Soupape selon la revendication 4 ou 5, caractérisée en ce que le piston de limitation de pression (55) soumis à une action de ressort de la soupape de limitation de pression (30) est mis en contrainte par deux ressorts de compression disposés en parallèle, dont l'un (57) est mis en compression dans la chambre de retour (60) contre le piston de limitation de pression (55) et l'autre (66) dans la chambre d'extrémité déchargée en pression contre la tige de piston comprenant une extrémité de guidage (63).
  7. Soupape selon l'une des revendications 1 à 6, caractérisée en ce que le compartiment de commande ou de commande de progression (21) est relié au canal de commande (X) par l'intermédiaire d'une soupape de dosage (84), avec laquelle le piston de commande ou de commande de progression (20) est soumis à l'action d'une quantité d'huile de commande limitée à une course déterminée du piston de commande (20).
  8. Soupape selon la revendication 7, caractérisée en ce que la chambre de dosage (102) de la soupape de dosage (84) est reliée au raccord de commande (115) et comprend une ouverture de soupape (107) avec un siège de soupape (109), à travers laquelle l'huile de commande arrive au compartiment de commande (21), et un élément de fermeture (110), qui s'appuie au moyen d'une tige (118) sur le piston de commande (20), et ceci de manière telle que dans la chambre de dosage (102), l'élément de fermeture (110) soit mobile de manière synchrone avec le piston de commande (20) entre le siège de soupape (109) et un point d'ouverture et à ce qu'il ferme le siège de soupape (109) pour une course imposée du piston de commande (20).
  9. Soupape selon la revendication 8, caractérisée en ce que l'ouverture de soupape (107) aboutit dans le compartiment de commande (21) sur le côté opposé au ressort de commande ou de commande de progression (147) et est entourée d'une surface de fermeture de forme annulaire (109), qui est située parallèlement au côté frontal du piston de commande soumis à la pression, en ce que la tige (118) traverse l'ouverture de soupape (107) avec un jeu important et en ce que l'élément de fermeture (110) est poussé par un ressort (111) pour l'appui de la tige sur le côté frontal soumis à la pression du piston de commande (20) et, après l'achèvement de la course imposée, sur le siège de soupape (109).
  10. Soupape selon la revendication 9, caractérisée en ce que le siège de soupape (109) comportant l'ouverture de soupape (107) de la soupape de dosage (84) est guidé de manière mobile et peut être positionné par rapport au compartiment de commande (21), en particulier que l'ouverture de soupape (107) de la soupape de dosage (84) est formée sur un piston de fermeture (119), qui ferme la chambre de soupape de dosage (102) par rapport au compartiment de commande (21) et qui, dans la chambre de soupape de dosage (102), est guidé et peut être positionné de manière à assurer une étanchéité et parallèlement au piston de commande (20).
  11. Soupape selon la revendication 10, caractérisée en ce que le piston de fermeture (119) peut être positionné de telle manière qu'il se mette en contact avec le piston de commande (20) et qu'il déplace et positionne le piston de commande (20) dans le sens d'un déverrouillage de l'élément de fermeture de commande pilote (8).
  12. Soupape selon la revendication 10 ou 11, caractérisée en ce que le piston de fermeture (119) est placé à l'extrémité libre d'une broche de réglage (106), en ce que la broche de réglage (106) comprend un canal central (108) placé en alignement avec l'ouverture de soupape (107) et qui est fermé par le bouchon (112) à l'extrémité libre de la broche de réglage (106), en ce que l'élément de fermeture (110) est guidé dans le canal central (108), en ce que le canal central (108) est soumis des deux côtés de l'élément de fermeture à la pression de commande et en ce que la broche de réglage (106) peut être rentrée ou sortie par vissage ou dévissage dans une forure taraudée (105), qui est parallèle au mouvement du piston de commande (20).
  13. Soupape selon la revendication 12, caractérisée en ce que dans l'une des positions d'extrémité de la broche de réglage (106), le piston de fermeture (119) pénètre dans le compartiment de commande (21), touche le piston de commande (20) et le déplace dans le sens d'un déverrouillage de l'élément de fermeture de commande pilote (8) (figure 8) et dans l'autre position d'extrémité, la distance entre le siège de soupape (109) et la surface frontale du piston de commande (20) se trouvant dans la position de repos est plus faible que la longueur de la tige (118).
  14. Soupape selon la revendication 12 ou 13, caractérisée en ce que le canal central (108) est soumis des deux côtés de l'élément de fermeture (110) à la pression de commande, et ceci par le fait que le canal de pression de commande (114) aboutit dans le canal central (108) directement devant la surface de fermeture du piston de fermeture et que l'élément de fermeture est guidé avec du jeu dans le canal central.
  15. Soupape selon les revendications 7 à 14, caractérisée en ce que la tige (118) est reliée de manière fixe avec l'élément de fermeture (110) ou est séparée de cet élément de fermeture (110) et en ce que la tige (118) est reliée de manière fixe avec le piston de commande (20) ou est séparée de ce piston de commande (20).
  16. Soupape selon l'une des revendications 7 à 15, caractérisée en ce que la soupape de dosage (84) est contournée par un canal d'étranglement (127) qui, après la fermeture du siège (109) par l'élément de fermeture (110), présente un étranglement plus important (125, 128) du flux d'huile de commande.
  17. Soupape selon l'une des revendications 7 à 16, caractérisée en ce que la soupape de dosage est contournée par un canal de mise en précontrainte (129, 131), dans lequel se trouve une soupape de précontrainte (130), au moyen de laquelle est imposée une différence maximale de pression entre le canal de mise en précontrainte (129) et le canal de commande restant (21).
  18. Soupape selon l'une des revendications 7 à 17, caractérisée en ce que la soupape de dosage est contournée par un canal de décharge, comme les canaux de by-pass (135, 137), qui relie le canal de commande avec le réservoir par l'intermédiaire d'une buse de by-pass (132) et d'un clapet anti-retour (133).
EP97907055A 1996-02-28 1997-02-28 Soupape de frein a maintien de charge Expired - Lifetime EP0883753B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19607452 1996-02-28
DE19607452 1996-02-28
DE19649752 1996-11-30
DE19649752 1996-11-30
PCT/EP1997/000992 WO1997032136A1 (fr) 1996-02-28 1997-02-28 Soupape de frein a maintien de charge

Publications (2)

Publication Number Publication Date
EP0883753A1 EP0883753A1 (fr) 1998-12-16
EP0883753B1 true EP0883753B1 (fr) 2002-04-17

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Application Number Title Priority Date Filing Date
EP97907055A Expired - Lifetime EP0883753B1 (fr) 1996-02-28 1997-02-28 Soupape de frein a maintien de charge

Country Status (6)

Country Link
US (1) US6098647A (fr)
EP (1) EP0883753B1 (fr)
JP (1) JP3617841B2 (fr)
KR (1) KR19990087371A (fr)
DE (1) DE59707059D1 (fr)
WO (1) WO1997032136A1 (fr)

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KR19990087371A (ko) 1999-12-27
WO1997032136A1 (fr) 1997-09-04
JP3617841B2 (ja) 2005-02-09
EP0883753A1 (fr) 1998-12-16
DE59707059D1 (de) 2002-05-23
US6098647A (en) 2000-08-08
JP2000505532A (ja) 2000-05-09

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