DD205727A1 - COMPRESSED BRAKE VALVE - Google Patents

Abstract

THE INVENTION RELATES TO A COMPOSITE CONTROLLED BRAKE VALVE FOR BELASTUNGSUNABHAENGIGEN SPEED CONTROL OF PULLING CHARGED TWICE acted upon PRESSURE POWER CONSUMERS, THE ONE OR Multi-part piston WITH IN INITIAL POSITION CLOSED ADJUSTABLE KEY CHOKE EQUIPPED IS WITH A bypass return valve PARALLEL IS BEING IN A LEAD IN OUTPUT POWER CONSUMER AN INLET SIDE MEASURING THROUGH AN INFLUENCE AND IN ANY DISCHARGE PIPE LEADING FROM THE DIFFERENT CONNECTION LINE AFTER THE ADJUSTABLE MAIN THROTTLE A FLOW-SIDE THROTTLE IS ARRANGED AND THAT ALL THE MEASURING MEASURES ARE ASSOCIATED BY A COMPONENT THROTTLE. BY THE INVENTION THE OBJECTIVE MANUFACTURING EXPENSES FOR SUCH COMPOUND CONTROLLED BRAKE VALVES SHOULD BE REDUCED. It is an object of the invention to provide such a perfection-controlled brake valve which has a simple constructive structure. THIS IS OBTAINED THAT THE PISTON IS EQUIPPED WITH TWO HEADS OF BRAZIL, WHICH IN BRAKING OPERATES ONE OF THE ADDITIONAL PRESSURE PRESENTED BEFORE THE INFLUENCE OF THE MEASURING THROTTLE AND THE OTHER THAT PREVAILS INTERPRETING IN THE BRAKE VALVE BODY IN THE BRAKE VALVE ENCLOSURE OF THAT HEADLINE.

Description

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Composite brake valve

Field of application of the invention

The invention relates to a composite-controlled brake valve for load-independent speed control of pull-loaded double-acting pressure flow consumers, comprising the following features:

a) in the housing of the brake valve, a one- or multi-piece piston is guided, which is provided with a closed in the initial position adjustable main throttle and

  is acted upon by a compression spring in the closing direction of the main variable throttle;

b) over the s te Uwe gabhäng ig increasing Durchfliißquerschnitt the main throttle consumer and the drain port of the brake valve are interconnected;

c) the main choke is connected in parallel with a discharge line check valve, which opens in the direction of action of the external load downstream of the compressed-current consumer and opens in the direction of the pressure-current consumer;

d) in the not interrupted by the bypass check valve connecting line of the pressure flow consumer, an inlet-side Meßdrossel is arranged;

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e) in the from the connection line with the bypass check valve on the side facing away from the pressure flow consumer side of the bypass check valve leading to the variable main throttle branch line a drain-side Meßdrossel is arranged;

f) the load-side terminal of the inlet-side Meßdrossel communicates with the valve-side connection of the outlet side Meßdrossel via a composite throttle in the connection is blocked either at full blocking or opening or only with complete blocking of .Flowing of the adjustable main throttle;

g) the individual pressure differences across the inlet-side Meßdrossel, the outlet-side Meßdrossel and the composite throttle are relatively small compared to the mean pressure difference across the variable main throttle.

Characteristic of the known technical solutions

The dynamic characteristics of such composite brake valves depend on the degree of division of the signal levels of the two jointly processed control variables "consumer discharge flow" and "consumer inlet pressure" on the spring-piston system acting as the comparator of the brake valve Such a structural design requires a double-precision fit to guide the piston in the housing, so as to avoid jamming of the piston due to the resulting risk of accidents, and therefore significantly increases the manufacturing cost Another disadvantage of the stepped piston is that the selected with the determination of the diameter of the two sections of the piston division rate can not be changed later.

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Object of the invention

The invention is intended to reduce the considerable production costs for such composite-controlled brake valves and make it possible to adapt the degree of division of the signal levels of the two sail sizes to the specific conditions of the respective system component.

Explanation of the essence of the invention

The invention has for its object to provide such a composite-controlled brake valve, which has a simple structural design and in which the degree of mixing of the two Hegelgrößen is variable.

According to the invention this object is achieved by the following features

h) the one-piece piston or the control piston of a multi-part piston has two equal-sized end faces, of which in braking mode, the one. End face in the opening direction of the adjustable main throttle with the applied upstream of the inlet side Meßdrossel inlet pressure and the other end face in Schließrichtung.der adjustable main throttle is applied to the prevailing in the limited of this other face pressure chamber in the housing of the brake valve intermediate pressure;

i) the pressure chamber is constantly in communication with the valve-side connection of the outlet-side measuring throttle via a second composite throttle in front of which the intermediate pressure arises during braking operation;

j) the pressure difference across the second composite choke is relatively small compared to the middle one. Pressure difference across the adjustable main throttle.

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In the composite controlled brake valve according to the invention with a multi-part piston, the spring chamber, which is known to be permanently connected to the consumer connection via a filling throttle, can be connected to the pressure chamber by a gate relief valve arranged in a known manner in the brake blocking piston.

embodiments

The invention will be explained in more detail below with reference to two embodiments. In the accompanying drawing show:

Pig. 1: the axial section of a non-tight-fitting composite-controlled brake valve in its functional diagram,

Fig. 2: the axial section of a tight closing composite controlled brake valve.

The niciit shown in Fig. 1 dichtschließende composite controlled brake valve is intended to control the speed of loaded in the output direction Druckstromverbrauche m with rotating output motion and reversible output direction. By appropriate actuation of the directional control valve 1, each of the two connection lines 2 and 3 of the pressure flow consumer 4 with the pump pressure line 5 and / or the drain line 6 are connected. In the direction of action of the external load located behind the pressure flow consumer 4 connecting line 3, a bypass check valve 7 is connected, which opens towards the pressure flow consumer 4 out and with an adjustable main throttle 8 is connected in parallel, on whose adjustment path dependent increasing flow area of the consumer port 9 and the drain connection. of the brake valve are interconnected. The overflow check valve 7 can be in the housing 11 of the brake valve

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integrated or flanged to it. In the housing 11 of the brake valve, a piston 12 is guided, the. provided with the throttle element 13 designed as a throttle element of the closed in the initial position adjustable main throttle 8 and is acted upon by a compression spring 14 in the closing direction of the adjustable main throttle 8. The piston 12 has two equal-sized end faces 15 and 16, of which the one end face 15 with an inlet-side Meßdrossel 17 _s .die in the not interrupted by the bypass check valve 7 AnschluJBleitung 2 of the pressure flow consumer 4 is., Via a branch line 18 in Connection is, which opens on the side facing away from the pressure flow consumer 4 side of the inlet-side Meßdrossel 17 in the connection line 2. The limited by the other end face 16 of the piston 12 pressure chamber 19 in, housing 11 of the brake valve is connected via a central bore 20 and radial bores 21 in the piston 12, radial bores 22 in the housing 11 of the brake valve and arranged in a connecting line 23 composite throttle 24, which is blocked at complete blocking of the flow area of the adjustable main throttle 8, with the consumer-side terminal of the inlet-side Meßdrossel 17 connectable. This pressure chamber 19, in which the compression spring 14 is inserted ,, is constantly. With the valve-side connection of a drain-side Meßdrossel 25? which is arranged in the from the connection line 3 with the bypass check valve 7 bm of the Druckstromverbraucher-4-facingh side of Ümgehungs check valve 7 leading to the adjustable main throttle 8 branch line 26, via a second, arranged in a connecting line 27 composite throttle 28th in connection. The individual pressure differences across the inlet-side measuring throttle 17, the composite throttle 24, the outlet-side measuring throttle 25 and the second composite throttle 28 are relatively small compared to the mean pressure difference across the main variable throttle 8.

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In the middle position O des.Wegeventils 1 shown in Fig. 1, the pump pressure line 5 is connected to the drain line 6, and the flow rate of the pump flows without pressure via the directional control valve 1 from. In this case, the compression spring 14 presses the piston 12 in the drawn starting position. A raised load is held by an unillustrated automatic parking brake in their respective position.

When switching the directional control valve 1 to the working regime "lowering the load" in. The switching position 1, the pump pressure line 5 to the connection line 2 and the drain line 6 are connected to the Anschiußleitung 3. The ZufluBstrom flows through the connecting line 2 with the inlet side Meßdrossel 17 to Druckstromverbraucher 4. Since the direct outflow from the Druckstromverbraucher 4 in the drain line 6 through the closed bypass check valve 7 in the connecting line 3 ¹ ^ d- by the closed adjustable main throttle 8 is prevented , builds up before the zulaufsei term measuring choke 1.7 in the connecting line 2 of the inlet pressure Pq. As a result, that the end face 15 of the piston 12 is acted upon via the branch line 18 and an optionally arranged therein damping throttle 30 with the voltage applied to the inlet side Meßdrossel 17 inlet pressure p _Q in the opening direction of the adjustable main throttle 8, the piston 12 against the effective direction of. Biasing force of the compression spring 14 moves. As soon as the consumer outflow can pass through the branch line 29 from the Yerbraucheranschluß 9 from the adjustment path increasing flow area of the axial throttle grooves I3 of the adjustable main throttle 8, arises in the branch line 26 before the outlet side Meßdrossel 25, a discharge pressure p. Simultaneously with or shortly after the opening of the flow cross section of the adjustable main throttle 8 is via the connecting line 27 with the second composite throttle 28, the pressure chamber 19; the central bore 20, the radial bores 21 and 22 and the connecting line

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23 with the composite throttle 24 a shunt connection between the drain port 10 and the consumer-side connection of the inlet-side Meßdrossel 17 made in the connection line 2, so that larger pressure differences between the discharge pressure p ^ and the consumer inlet pressure p ,, be compensated virtually instantaneously. The prevailing in the pressure chamber 19 intermediate pressure p _z , which is formed in the connection line 27 in front of the second composite throttle 28 and acts on the end face 16 of the piston 12 in the closing direction of the main variable throttle 8, takes a value between the Verbraucherzulaufdruck pxj and the discharge pressure p. and is determined by the flow resistance of the two composite chokes 24 and 28. The composite controlled brake valve performs during the braking process two coupled control functions, whereby both a pressure and current-dependent adjustment of the main variable throttle 8 is given. The control variable "consumer discharge flow" is compared with the Pührungsgröße "inflow" by the resulting on the outlet side Meßdrossel 25 and the inlet side Meßdrossel 17 current-dependent pressure drops on the piston 12 cause oppositely directed actuating forces. Likewise ,, but in the reverse sense of action, is a comparison between the force acting on the piston 12 of a component of the feed pressure p _Q forming consumer inlet pressure p,., Which acts as a second control variable, with the reaction force of the compression spring 14 occurring as a reference variable .. The control system undergoes further stabilization by means of the two series-connected composite throttles 24 and 28. Purely statically, they always bring the consumer inlet pressure p 1 into the order of magnitude of the discharge pressure ρ, by compensating for greater deviations of these two pressures from one another by means of a corresponding bypass current. In the connection line 2 between the inlet-side Meßdrossel 17 and the pressure flow consumer 4 is characterized both negative pressure and an excessively high increase in the consumer supply pressure p ^ prevented. Dynamically based

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Stabilizing effect of composite throttles 24 and 28 on the fact that the temporal pressure changes the discharge pressure p ^ and. the consumer inlet pressure p ^, which always run in opposite directions to each other, are brought to interference. By changing the flow cross sections of the two composite reactors 24 and 28, the degree of division of the signal level of the two control variables can be adapted to the specific conditions of the respective part of the plant. A mounted on the piston 12 stopper 31, which also serves to Püiirung the compression spring 14, limits the travel of the piston 12 and thus determines the largest possible opening of the flow area of the main variable throttle. 8

If, the directional control valve 1 in the working regime "lifting the load" is in the switching position 2, the pump pressure line 5 are connected to the connecting line 3 and the drain line 6 with the connection line 2 in connection. Then on the one hand, the end face 15 aes piston 12 relieved of pressure, and on the other hand acts on the outlet side Meßdrossel 25 and the second composite throttle 28 in the pressure chamber 19 propagating inlet pressure on the end face 16 of the piston 12 so that the piston 12 thereby and by the effect the biasing force of the compression spring 14 is printed in the drawn starting position. There. in this position, the piston 12, the shunt connection between the leads 3 and 2, is interrupted by the composite throttles 28 and 24, the pressure flow can only flow through the connecting line 3 and the opening bypass Eückschlagventil 7 to the Druckstromverbraucher 4 and from there through the Connecting line 2 discharged into the drain line 5. The resulting before the inlet-side Meßdrossel 17. Pressure secures the necessary discharge pressure of the pressurized electricity consumer 4 while the load is being lifted.

The tightly closing composite-controlled brake valve shown in FIG. 2 is used to regulate the speed of pulling

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currently loaded double acting hydrostatic working cylinders. It is also particularly suitable for. Construction machinery, which must act in the effective direction of the load with operating pressure. In the housing 11 of this brake valve is the difference of the non dichtschließe.nden composite controlled brake valve of FIG. 1, a multi-part piston 12 out of a two equal sized end faces 15 and 16 having control piston 32, one with the axial throttle grooves 13 of the main variable throttle 8 and also two equal-sized end faces provided Bremssperrkolben 33 u-ßd. a built in the brake piston 33, serving to depressurize. Pre-relief valve 34- consists. The pressure relief is achieved in that by connecting the Vorentlastungsventils 34 by means of a control piston 32 mounted on Aufstoßstiftes 35 a connection between the via a Fülldrossel 36 constantly connected to the load port 9, the brake piston 33 acting on the compression spring 14 receiving spring chamber 37 and the pressure chamber 19 is produced. On the brake piston 33, a conical sealing surface 33 is provided, by their interaction with a sealing edge 39 i ^ - housing 11 of the brake? Valve the adjustable main throttle 8 is shut off leak-free in the starting position. The pressure chamber 19 is opposite to the non-tight-fitting composite brake valve to Pig. 1 via axial bores 40 and a Hingkanal 41 in the control piston 32 and arranged in the connecting channel 42 in the housing 11 of the brake valve composite throttle 24 which is shut off at full blocking or opening of the flow area of the adjustable main throttle 8, with the consumer side of the inlet side Meßdrossel 17 in connectable to the connecting line 2 and is constantly connected to the valve side of the outlet side measuring throttle 25 arranged in one of a low-pressure side of the adjustable main throttle 3 annular channel 43 in the housing 11 of the brake valve to the connecting line 3 leading connection channel 44

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via the second composite throttle 28 in conjunction.

In the middle position O of the directional control valve 1 shown in FIG. 2, in which the pump pressure line 5 is connected to the discharge line 6, the delivery flow of the pump flows without pressure via the directional control valve 1. The voltage applied to the consumer terminal 9 load pressure po propagates via the filling throttle Jo and the central bore Λ 5 in the spring chamber 37 continues. By the action of the load pressure pp and the biasing force of the compression spring 14 in the spring chamber 37, the brake control piston 33 is pressed against the sealing edge 39 in the housing 11 of the brake valve. Since the load pressure p ~ also acts on the blocking elements of the pre-relief valve 34 and the bypass check valve 7, these valves are closed, and the load is kept leak-free in their respective position.

When switching the directional control valve 1 zum.Arbeitsregime "lowering the load" in the switching position 1, wherein the pump pressure line 5 to the connecting line 2 and the drain line B mit.der lead 3, the inflow flow through the connecting line 2 with the inlet-side Meßdrossel 17th to Druckstromverbraucher 4. Since the Ümgehungs-Eückschlagventil'7 in the connecting line 3, the adjustable main throttle 8 and the Vorentlastungsventil 34 are closed and shut off the Verbraucherabflußstrom, builds before the inlet-side Meßdrossel 17 in the connecting line 2, the inlet pressure p _Q on a branch channel 46 in the housing 11 of the brake valve., An annular channel 47 and radial bores 4-8 in the control piston 32 and an optionally disposed therein damping damper 30 acts on the end face 15 of the control piston 32 and the control piston 32 moves to the brake locking piston 33. Due to the ratio of the end surface 15 of the control piston 32 to the ball seat surface of the pre-relief valve 34 which is acted upon by the load pressure P2 of approximately 30: 1, only a low inlet pressure Pq is required.

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to lift by means of the Aufstoßstiftes 35 Eugel the Vorentlastungsventils 34 against the action of the resulting from the load pressure P ₂ compressive force and the biasing force of the valve spring from its seat. Because the opened Vorentlastungsventil 3 ^ has a much lower flow resistance than the Eülldrossel 3 ^ then takes place the relief of the brake piston 33, and the pressure in the spring chamber 37 is built up on the run-off in the connecting channel 44 before MeJSdrossel 25 resulting discharge pressure p , from. In. Unlocked Vorentlastungsventil 34- is the control piston 32 on the brake piston 33 and forms with this a synchronously moving sinew. After further increase of the inlet pressure Pq acting in the closing direction of the adjustable main throttle 8 biasing force of the compression spring 14 is overcome, - and the VerbraucherabfIuBstrom can via the consumer terminal 9j the axial throttle grooves I3 in the brake piston 33, the annular channel 43, the connecting channel 44 with the drain side Measuring throttle 25 and the drain port 10 in the connecting line .3 and from there into the drain line 6 long. Simultaneously with or shortly after the opening of the flow cross section of the adjustable main throttle 8 is via the connecting channel 49, the second composite throttle 28, the pressure chamber 19 »the axial bores 40, the annular channel 41 and the connecting channel 42 with the composite throttle 24 a shunt connection between the valve side of outlet side .Meßdrossel 25 and the consumer side of the inlet-side Meßdrossel 17 produced, so that larger pressure differences between the discharge pressure p, and the consumer inlet pressure p ^ are compensated virtually instantaneously. The prevailing in the pressure chamber I9 intermediate pressure p ", which arises in the braking operation in front of the second composite throttle 28, propagates through the open Vorentlastungsventil 3 ^ UiKi- the central bore 45 in the JTederraum 37 and thus acts on the two same sized end faces of the brake piston 33 Since this causes the resulting damage to the brake piston 33

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cancel the pressure forces and the intermediate pressure p "also acts together with the Heäktionskraft the compression spring 14 · on the end face 16 of the control piston 32 in the closing direction of the main variable throttle 8, the Begelungsprinzipien the non-tight closing composite controlled brake valve of FIG. 1 and the dichtschließenden.verbundgesteuerte Brake valve of FIG. 2 completely the same.

If the piston ring surface of the hydrostatic used as Druckstromverbraucher 4. Working cylinder - for example, in universal excavators with backhoe during the excavation process - acted upon in the effective direction of the outer, pulling load with operating pressure, so far moved by the generated by the pump inlet pressure p _{Q of} the control piston 32 and the Breinssperrkolben 33, until the stop 31 .am Housing 11 of the brake valve is applied and the flow area of the adjustable main throttle 8 is fully open. Since then the shunt connection between the Anschlußieitungen 3 uncl 2 via the composite chokes 28 and 24 is interrupted and the entire inflow flow through the connecting line 2 to the Druckstromverbraucher 4, this can thereby be supplied to the full available hydrostatic drive power.

If the directional control valve 1 is switched back to its middle position O, the inlet pressure Pq collapses and no opening force acts on the multi-part piston 12. By the force of the valve spring of the Vorentlastungsventils 34, which must be so large that they can move the control piston 32, the. Vorentlastungsventil 34 is closed in the brake control piston 33. About the consumer terminal 9? the Fülldrossel 36 and the central bore 45 builds up in the spring chamber 37, the load pressure pg on the brake piston 33 in conjunction with the force of the compression spring 34 moves the control piston 32 in the closing direction of the main variable throttle 8 and finally the conical sealing surface 38 on the brake piston

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33 S © Sen presses the sealing edge 39 in the housing 11 of the brake valve. Now the load is again kept leak-free in their respective position.

When the directional control valve 1 is in the working regime "lifting the load" in the switch position 2, in which the pump pressure line 5 with the connection line 3 and the drain line 6 with the connection line 2 are in communication and the end face 15 aes control piston 32 is depressurized, the acts on the outlet-side Meßdrossel 25 and the second composite throttle 28 in the pressure chamber 19 propagating inlet pressure. the end face 15 of the control piston 32 and pushes it into the drawn starting position * In this position of the multi-part piston 12, the shunt connection between the leads 3 and. 2 via the 'composite throttles 28 and 24 also interrupted, and the pressure flow can only via the connecting line 3> äas opening bypass check valve 7.and the consumer terminal 9 to the pressure flow consumer 4 · get where it causes the load is lifted. Since this in the spring chamber 37 via the Eülldrossel 35 and the ^central. Builds bore · 4-5 the feed pressure, the main variable throttle 8 is closed.

Claims (2)

241 6 0 7 3 Invention claim 1. A compound-controlled brake valve for load-independent speed control of pull-loaded double-acting pressure flow consumers, comprising the following features: a) in the housing of the brake valve, a one- or multi-part piston, out, which is provided with a closed in the initial position adjustable main throttle and is acted upon by a compression spring in the closing direction of the main variable throttle; b) the Terbraucher- and the drain port of the brake valve are blinded to each other via the adjusting cross-section of the main throttle depending on the adjustment path; c) the main throttle · is connected in parallel with a in the direction of action of the external load located behind the pressure flow consumer connecting line bypass check valve that opens towards the pressure flow consumer out; d) in the not interrupted by the bypass check valve connecting line of the pressure flow consumer, an inlet-side Meßdrossel is arranged; e) in the branch line leading from the connection line with the bypass check valve on the side of the non-return check valve facing away from the pressure flow consumer downstream of the adjustable main throttle, an outlet-side measuring throttle is provided. 241607 3 orderly; f) the verbrauciierseitige connection of the inlet-side Meßdrossel communicates with the valve-side terminal of the outlet side Meßdrossel via a composite throttle in connection, which is shut off either at full blocking or opening or only with complete blocking of the flow area of the adjustable main throttle; g) the individual pressure differences over the inlet-side measuring throttle, the outlet-side measuring throttle and the composite throttle are relatively small compared to the mean pressure difference across the variable main throttle; characterized by the following features: h) the one-piece piston (12) or the control piston (32) of a multi-part piston (12) has two equally sized end faces (15; 16), of which in braking operation, the one end face (15) in the opening direction of the adjustable main throttle (8) in the closing direction of the adjustable main throttle (8) with the pressure chamber (19) in the housing ( 11) of the brake valve prevailing intermediate pressure (p ^ ·) is applied; i) the pressure chamber (19) is constantly connected to the valve-side connection of the outlet-side Meßdrossel (25) via a second composite throttle (28) in connection, in front of the intermediate pressure during braking operation (P ₂ ) is formed; 241607 3 j) the pressure difference across the second Yerbunddrossel (28) is relatively small compared to the mean pressure difference across the main variable throttle (8). Compound-controlled brake valve nach- point 1 with a multi-part piston, characterized in that the known via a Fülldrossel (36) permanently connected to the consumer terminal (9) Pederraum (37) by a known manner in the brake piston (33) arranged pre-relief valve (34 ) is connectable to the pressure chamber (19). For this 2 pages drawings