EP1500825A2 - Multiway valve - Google Patents

Abstract

The valve has 2 coaxial control sliders (8,10) within a slider bore (52), for connecting 2 load terminals (A,B) with a pressure space (P) or a feedback space (R), held in an initial position by a spring device (58) with a spring element positioned between the sliders. The spring device has a stop for limiting the maximum working length of the spring element., provided by 2 spring plates mounted on a tension rod.

Description

The invention relates to a directional control valve according to the preamble of claim 1

Such directional control valves are for controlling double-acting and single-acting consumers. One Directional control valve with two spools in one spool bore is disclosed in DE 36 29 479 A1. In the basic position the two spools are spaced apart and the two working connections are towards the tank open. In a one-sided operation of the spool is the one spool in the direction of deflected second control slide and takes this after Covering a path corresponding to the distance.

The disadvantage of this solution is that in one-sided Actuation of the controlled spool a large He has to go back to the second spool runs up and takes this.

Another directional valve is disclosed in US 6,408,877 B2 shown. In this solution, two spools are for one through an outer spring up to a stop be charged to each other and become the other at the same time pushed apart by a middle spring. The Preload of the middle spring is much higher than the set of the outer springs, so that in a one-sided Actuation moves the spool together should be without the middle spring compressed becomes.

The strong middle spring is likely to be the response However, the known directional control valve adversely affect.

Object of the present invention is a directional control valve to provide that eliminates the aforementioned disadvantages and both for controlling double acting as well single-acting consumer is suitable.

The problem is solved by a directional control valve with the Features according to the patent claim 1.

According to the directional control valve for driving a Consumer's two spools, the basic position are biased, being between the tax pushers arranged a spring device with a spring element is, whose axial length is limited.

Thus, the spools are by the "bondage" of the centrally arranged spring element only up a certain measure of each other, so that the Control slide in the basic position substantially over the bias of their respective outer spring is subjected to force and a defined basic position taking.

In a preferred embodiment, the limit is as a drawbar with two movable spring plates executed, via the spring element, preferably a Compression spring, against each shoulder surface of the drawbar are curious.

In another preferred embodiment the spool two axially displaceable tensile body, which engage with hook-shaped end portions and the maximum length in its limit position of the spring element and thus determine the bias.

The gap is advantageously between the be relieved of pressure on both control valves to the tank. The tank holes for pressure relief are preferred trained in the tax pushers.

In a particularly preferred embodiment formed a stop between the two spools, against the the spool when acted upon can be tensioned with a maximum control pressure. Advantageous at the stop is that a single-acting consumer can be controlled via the directional control valve; and Although the one spool is against the stop driven and the second spool is in interaction the spring forces of its outer spring and the middle Spring element as a function of the control pressure emotional.

Preferably, the stopper is a snap ring, the is accommodated in a housing-side inner circumferential groove.

Preferably, between the spools and the Working connections per a lockable blocking block provided by applying an unblocking control pressure in the outflow direction. The blocking blocks each have a poppet piston, which from the drain side Load pressure can be acted upon, so that the blocking blocks For example, when pulling load a flow control is possible.

For constant control of the control pressure can downstream arranged the spool valve per a pressure control valve be.

Advantageously, the directional control valve is a 6-position valve executed.

Other advantageous embodiments of the invention are the subject of further subclaims.

Figur 1 ein Schaltschema eines erfindungsgemäßen LS-Wegeventils in Grundstellung,

Figur 2 eine vergrößerte Darstellung des Wegesystems aus Figur 1,

Figur 3 eine perspektivische Darstellung einer Federeinrichtung aus Figur 1,

Figur 4 einen vergrößerten Teilschnitt einer Anordnung der erfindungsgemäßen Federeinrichtung aus Figur 3,

Figur 5 eine perspektivische Darstellung einer zweiten erfindungsgemäßen Federeinrichtung,

Figur 6 ein Schaltschema des LS-Systems aus Figur 1 doppelwirkend bei Betätigung eines Steuerschiebers,

Figur 7 ein Schaltschema des LS-Systems aus Figur 1 doppelwirkend im Freigang,

Figur 8 ein Schaltschema des LS-Systems aus Figur 1 einfachwirkend in Grundstellung, und

Figur 9 ein Diagramm mit beispielhaften Schaltstellungen des Wegeventils aus Figur 1.

The following is a detailed explanation of a preferred embodiment of the invention with reference to schematic representations. Show it

1 shows a circuit diagram of an inventive LS-way valve in basic position,

FIG. 2 shows an enlarged illustration of the path system from FIG. 1,

FIG. 3 shows a perspective view of a spring device from FIG. 1,

FIG. 4 shows an enlarged partial section of an arrangement of the spring device according to the invention from FIG. 3,

FIG. 5 is a perspective view of a second spring device according to the invention,

FIG. 6 shows a circuit diagram of the LS system from FIG. 1 double-acting upon actuation of a control slide,

FIG. 7 shows a circuit diagram of the LS system from FIG. 1, double-acting in clearance;

Figure 8 is a circuit diagram of the LS system of Figure 1 single acting in basic position, and

9 shows a diagram with exemplary switching positions of the directional control valve from FIG. 1.

FIG. 1 shows a circuit diagram of an LS system 2, about an unillustrated consumer with pressure medium is available. The LS system 2 has an individual pressure compensator 4, a proportionally adjustable 6-way valve 6 with two spools 8, 10, two pressure control valves 12, 14 and two unlockable Blocking blocks 16, 18 on, beyond the consumer a pump, not shown, pressure medium supplied and over which the pressure medium from the consumer to a not shown tank is traceable. About the pressure control valves 12, 14 may each have a control pressure for moving the spool 8, 10 and an unlock control pressure for switching through the blocking blocks 16, 18 set become.

For example, the consumer is a double-acting Differential cylinder, which with its cylinder space on a working connection A and with an annulus to one Work connection B is connected. The pump is on a pressure port P and the tank to a drain port R connected.

According to Figure 1, the individual pressure compensator 4 - Called following pressure balance - upstream of the directional control valve 6 (LS system). She has a pressure compensator piston 20, the axially displaceable in a pressure balance bore 22 is included. The pressure balance piston 20 is over a middle annular groove in a control collar 24 and a spring collar 26 divided. In such a circuit LS the pressure loss is formed over that of the directional control valve 6 Metering irrespective of the load pressure of the consumer kept constant. Since these LS systems from the State of the art, may be for further explanation the interaction of the metering diaphragm and the pressure balance 4 be waived.

The control collar 24 has a plurality of control notches, form a control edge 28 and on the one Pressure medium connection from one to the pressure port P connected pressure chamber 30 to an adjacent pressure channel 32, in two to directional control valve 4 leading channels 48, 50 branched, on or is zuusteuerbar. The pressure compensator piston 20 is by means of a at one end of the Pressure balance bore 22 supported control spring 34 in a Biased direction in which the connection between the Pressure chamber 30 and the pressure channel 32 is open. A the Control spring 34 receiving spring chamber 36 is at a first control channel 38 connected to a shuttle valve 40 leads.

The right in Figure 1 end face of the pressure balance bore 22 limited with the opposite end face the control association 24 a control room 42, which has a second control channel 44 with the pressure in the pressure channel 32nd is charged. For damping high-frequency vibrations is in the second control channel 44, a damping throttle 46 provided.

The two spools 8, 10 are in a slide bore 52 guided axially displaceable. The spools 8, 10 are identical and over a Centering spring assembly 54, 56 in its illustrated Pretensioned basic position, where it has an inventive Spring device 58, to the later reference Figures 3, 4 and 5 will be discussed in detail, spaced apart from each other. The centering spring arrangements 54, 56 each have a centering spring 60, 62, the taken in an end control pressure chamber 64, 66 are. The centering springs 60, 62 immerse each in one cup-like body 68, 70 and support whose inner bottom surface 72, 74 from where they to Housing shoulders 134, 256 with their opposite End section via axially displaceable spring plates 76, 78 attack.

The spool 8, 10 can be moved in principle from its basic position mechanically, electrically or hydraulically in a working position. In the embodiment shown here, the actuation of the spool 8, 10 hydraulically via in each case an individual control pressure P _BX and P _AX in the control pressure chambers 64, 66, which are adjusted via the pressure control valves 12, 14.

The maximum displacement of the spool 8, 10 is limited by a stop 80 according to the invention in the middle of the spool bore 52. The stopper 80 is formed as a snap ring and housed in an inner circumferential groove of the slide bore 52 fixed to the housing. When the spool valves 8, 10 are acted upon with a sufficient control pressure P _BX or P _AX , they run onto the snap ring 80 and thus assume a defined stop position. A detailed explanation of the stop 80 will follow later in the description.

Preferably, at least one spool 8, 10th with a not shown odometer for accurate determination provided the respective hub.

The slide bore 52 is provided according to the enlarged view in Figure 2 with a plurality of annular spaces. On both sides of the stop 80, two annular discharge chambers 82, 84 are provided, which are connected via tank channels R to the tank. Between the stopper 80 and the discharge spaces 82, 84, a respective relief space 86, 88 is arranged, which is also connected to the discharge space 82, 84 with a corresponding position of the spool valve 8, 10. Adjacent to the drainage spaces 82, 84, two further annular spaces are provided, wherein in the following the left is designated as the supply space 90 and the right as the return space 92. In addition to the flow or return space 90, 92 are two pressure chambers 94, 96 which are connected to the channels 48, 50. In the direction of the control pressure chambers 62, 64 are each three further annular spaces 114, 116, 118; 120, 122, 124, which are provided for forwarding the control pressure P _X on topping piston 172, 174 of the blocking blocks 16, 18 or for pressure relief of the topping piston 172, 174. Here, the middle annular spaces 116, 122 via connection channels 184, 186 with Entsperrungsräumen 180, 182 of the poppet 172, 174 connected, the outer annular spaces 118, 124 are connected to the drain port R and the inner annular spaces 114, 120 are each having a control pressure line 258th , 260 for supplying the control pressure P _X.

The spools 8, 10 have in the area of the drainage spaces 82, 84 two control collars 98, 100, in their annular end faces each control notches are provided so that at each control collar 98, 100 a flow control edge 102, 104 is formed. In the area of the pressure chambers 94, 96 the spools 8, 10 each have a control collar 106, 108, with a variety of control notches for Forming an inlet control edge 110, 112 is formed. The geometry of the control collars 106, 108 is designed to that in the illustrated basic position of the flow chamber 90th and the return space 92 to the adjacent pressure chamber 94, 96th and to the adjacent discharge space 82, 84 are closed. In the area of the discharge spaces 86, 88 is in the spools 8, 10 each have a circumferential groove 130, 132, so that when appropriate position of the spool 8, 10 the relief spaces 86, 88 to the tank can be relieved of pressure. Furthermore, in the area the arrangement of the three further annular spaces 114, 116, 118; 120, 122, 124 in the control valves 8, 10 each one Circumferential 126, 128 provided so that the poppet 172, 174 can be transferred to an unlocking or rest position are. In the illustrated basic position are the Relief spaces 86, 88 relieved to the tank and the blocklocks 16, 18 in the outflow direction in its blocking position.

The blocking blocks 16, 18 are identical and have a locking piston 136, 138, which in a bore 140, 142 out and against a valve seat 144, 146 is biased. In the illustrated blocking position is the connection between a flow chamber 148 and a Working chamber 150 and a working chamber 152 and a Return chamber 154 shut off leak-free. The locking piston 136, 138 are designed as a hollow piston, wherein in a piston crown designed as a cone a pilot cone 156, 158 is guided, which has a pilot spring 160, 162 biased against a pilot seat 164, 166 is. Also, the locking piston 136, 138 on this Pilot springs 160, 162 against their valve seat 144, 146 biased. The pilot poppets 156, 158 each have a projection 168, 170, which in the direction of the lead or return chamber 148, 154 protrudes.

In the end portions of the bores 140, 142 remote from the blocking pistons 136, 138, the poppet pistons 172, 174 designed as stepped pistons are arranged so as to be axially displaceable, whose piston rods 176, 178 extend in the direction of the projections 168, 170 of the pilot poppets 156, 158. In each of the Aufstoßkolben 172, 174 receiving end portions of the bores 140, 142 opens one of the Entsperrungsräume 180, 182, which is connected via one of the connecting channels 184, 186 with one of the annular spaces 116, 122 and in the thus the control pressure P _X out can be.

The flow chamber 148 of the locking block 16 is connected via a Intermediate channel 188 with the flow space 90 and accordingly the return chamber 154 of the locking block 18 via an intermediate channel 190 connected to the return chamber 92.

In the embodiment illustrated in FIG. 1, the supply space 90 and the return space 92 are each connected via a control line 192, 194 to the two inputs of the shuttle valve 40. That is, via the shuttle valve 40, the larger of the two in the flow chamber 90 and the return chamber 92 tapped load pressure Y _A , Y _{B is reported} in the control channel 38. Furthermore, the load pressures Y _A , Y _B via control lines 196, 198, which extend between the relief chambers 86, 88 and the control lines 192, 194, to the drain spaces 82, 84 relieved.

Figure 3 shows an enlarged and sectioned partial view a preferred embodiment of the invention Spring device 58.

The spring device 58 has a limitation for limiting the effective length and thus the bias of a Spring element 200. It has a pull rod 202 with two slidable spring plates 204, 206, which in the illustrated basic position on the spring element 200, preferably a compression spring, in each case against an end side Shoulder surface 208, 210 of the pull rod 202 tensioned are. Thus, the compression spring 200 is over the limit "Tied". The spring plates 204, 206 surround axially slidably the pull rod 202, so that by displacement at least one of the spring plates 204, 206, the spring 200th can be upset. The bias of the compression spring 200th is chosen so that its biasing force is greater than the Spring force of the centering springs 60, 62 of the spool 8, 10 is at maximum stroke.

The spring device 58 is shown in sections in FIG. 4 in a gap 212 between the spools 8, 10 added. To clarify the arrangement the left spool 8 is partially cut shown. The spring device 58 emerges in the basic position the spool 8, 10 sections in each case in a stepped blind hole 216 of the spool 8, 10 and supports with their spring plates 204 an annular surface 218 of the stepped bore 216 from. The axial Distance between the two spools 8, 10 is in the basic position substantially over the axial length the prestressed compression spring 200 determines, wherein due to the bias of the centering springs 60, 62 the Spring plate 204, 206 are supported on the annular surfaces 218. The pull rod 202 is with its end face 220 from the ground 222 of the blind hole 216 spaced so that at an actuation of at least one of the spool 8, 10th move the pull rod 202 toward the bottom 222 can and thus the relative distance between the two Spools 8, 10 can be reduced. The gap 212 is in each case via an axial tank bore 214, the into the bottom 222 of the stepped bore 216 opens and a radial tank bore 224 with the drain chamber 82 in conjunction.

Furthermore, the snap ring 80 is in the inner circumferential groove 234 of the slide bore 52 in the middle of the Gap 212 can be seen against which the spool 8, 10 can be brought into abutment position.

Another preferred embodiment of the invention Spring device 58 is shown in FIG. The limitation is carried out by two tensile bodies 226, 228, preferably on the control valves 8, 10th are formed and with hook-shaped end portions 230, 232 mesh. The tensile bodies 226 ', 228 become encompassed by the compression spring 200, the end to End faces 236, 238 of the spool 8, 10 is supported and by the hooking of the two tension bodies 226, 228 biased in limiting function and thus in their axial length is limited. By an operation at least one of the spool 8, 10 can accordingly the above-described embodiment of Figures 2 and 3 the compression spring 220 compressed and thus the relative Distance between the spools 8, 10 changed become.

The following is the function of the LS system with reference to Figures 1 and 2, 4, 6, 7 and 8 described.

The figures 1 and 2, 6 and 7 show an example "double-acting functions" of the directional control valve 6, for example. when controlling a double-acting lifting cylinder and FIG. 8 shows a "single-acting function", for example. when controlling a single-acting lifting cylinder.

It should be noted that the switching positions shown only to be understood as examples. That's the way it is Of course possible, the LS system 2 due its mirror symmetry to drive. To repetitions To avoid, these are mirrored Switch positions not explained in detail.

Figures 1 and 2 show the directional control valve 4 in prestressed Basic position or in neutral position, in the the blocking blocks 16, 18 are closed and pressure medium between a consumer and the blocking blocks 16, 18 is clamped so that a consumer load safely to the Working connections A, B can be kept.

The spool 8, 10 are not supplied with control pressure P _BX , P _AX and thus centered on the Zentrierfederanordnungen 54, 56. The connection from the pressure chamber 30 to the pressure channel 32 is closed by the control edge 28. Likewise, a connection of the flow space 90 and the return space 92 with the discharge spaces 82, 84 via the flow control edges 102, 104 is closed. The load pressures Y _A and Y _B , which are tapped in the flow chambers 90, 92 are guided via the control lines 192, 194, 196, 198 and slide edges of the circumferential grooves 130, 132 to the tank. Furthermore, the unblocking spaces 180, 182 are relieved via the annular grooves 116, 122, slide edges of the circumferential grooves 126, 128 and the annular grooves 118, 124 to the tank.

FIG. 6 shows the LS-way valve arrangement 2 in one Work position in which the right working connection B to Tank relieved and the consumer on the left working connection A is supplied with pressure medium.

The right spool 10 is acted upon by the control pressure chamber 66 with the control pressure P _AX , so that it is moved to the left against the stop 80 and placed in the stop position. Due to the large biasing force of the compression spring 200 this is only negligibly compressed, so that it acts as a transmission element for transmitting the axial deflection of the right spool 10 on the left spool 8. Both spools 8, 10 behave more or less like a common spool and the left spool 8 is deflected to the left in accordance with the movement of the right spool 10. In this case, the channel 50 is closed via the control collar 108 and the intermediate channel 190 of the return chamber 154 is connected via the flow control edge 104 with the discharge space 84. At the same time, the LS discharge for Y _{B is} closed to the discharge space 84 and the control pressure P _{X is conducted} into the release space 182. At sufficiently high control pressure P _X , the poppet 174 on the pilot poppet 158 and lifts it against the force of the pilot spring 162 and against the force acting on the seat load pressure Y _B from the pilot seat 166, so that the locking block 18 is controlled in the outflow direction and the outflowing pressure medium from the working chamber 152 can flow into the return chamber 154.

The left spool 8 opens its determined by the inlet control edge 110 Zumeßblendenquerschnitt and pressure fluid flows from the pressure channel 32 in the flow chamber 90 and from there via the blocking block 16 to the consumer. The LS discharge for Y _A to the discharge chamber 82 is closed, so that via the control line 192 of the load pressure Y _{A is} guided to the shuttle valve 40 and from there into the spring chamber 36 of the pressure compensator 4. At the same time the pressure in the channel 50 is guided into the control chamber 42. Consequently, the pressure compensator 4 takes a corresponding control position in the interaction of the spring force of the control spring 34 and the load pressure Y _A with the pressure in the control chamber 42, in which the pressure drop of the feed stream is constant over the Zumeßblende. Thus, the supply current to the load is load-independent.

For load pressure independent control of the flow, e.g. when pulling load, the blocking blocks 16, 18 designed so that they work as a pressure regulator can. Corresponding to the right in Figure 6 shown Block 18, the poppet 174 immersed in tax druckbeaufschlagter Position in sections in the Working chamber 154 and is with the pressure in the Working chamber 154 is applied, so that, depending on the size the opening cross section above the pilot seat 166 and thus changed over the valve seat 146.

Figure 7 shows the directional control valve 6 in the clearance, in the the pressure chamber 30 is closed and both working connections A, B, of the consumer with the respective outflow space 82, 84 are connected.

Upon application of both control valves 8, 10 with identical control pressure P _BX , P _{AX they} are brought into abutment position on the stop 80 after overcoming a pressure threshold corresponding to the bias of the middle compression spring 200 and the pull rod 202 dives into the blind bores 216 (FIG ) one. The relative position of the spring device 58 to the stop 80 is unchanged.

As already explained under FIG. 6 on the right-hand control slide 10, the supply and return chambers 148, 152 are connected to the discharge spaces 82, 84 via the discharge control edges 102, 104, the control pressure P _X being simultaneously guided into the release chambers 180, 182 and the two blocking blocks 16, 18 through in the flow direction.

It is advantageous that the clearance is achievable, without that must be gone over an active position, at the at least briefly the pressure chamber 30 with one of Working connections A, B is to connect.

FIG. 8 shows a working position of the LS system 2 for controlling a single-acting consumer. The right spool 10 is in stop position and the left spool 8 is acted upon by control pressure P _BX , that it is transferred against the bias of the central compression spring 200 in a load-holding position, in the working port A opposite the pressure chamber 94 and the drain chamber 82 is.

As already explained in FIGS. 6 and 7, FIG the working connection B in stop position 'of the right Spool 10 is connected to the drain space 84 and thus relieved to the tank, the lock block 18 at the same time acts as a pressure regulator for the flow.

The left spool 8 is acted upon independently of the right spool 10 with a control pressure P _BX and in a load-holding position, with a corresponding choice of the control pressure P _BX the working port A via the inlet control edge 110 with the pressure chamber 94 and thus with the pressure channel 32 (see 6) or via the flow control edge 102 to the drainage space 82 (see FIG. For example, an increase of the control pressure P _BX (control piston 8 is deflected to the right by its center position against the force of the compression spring 200) a lifting of a load and a reduction of the control pressure P _BX (control piston 8 is from its center position by means of the force of the compression spring 200 after shifted left) mean a sinking of a load.

Advantageous to the illustrated control of Spool 8, 10 is that the right spool 10 has moved to a defined position and thus the Force of the middle compression spring 200 on the left spool 8 is determined, and the left spool 8 is in a middle position, from which he passes through Increase or decrease in a corresponding load-lifting or load-reducing position can be transferred. A Such control is therefore particularly suitable for Control of single-acting consumers.

On the basis of Figure 9 switching positions are explained, which can be achieved with different control pressures P _AX , P _AB . Of course, with appropriate selection of the control pressures P _AX , P _BX any intermediate position can be approached.

Switching position 240 represents the basic position of the directional control valve 6. The control pressures P _AX , P _BA are zero and the working ports A, B, the pressure chamber P and the tank port T are closed against each other.

When increasing the control pressure P _AX , the directional control valve 6 changes over to the switching position 242, in which the pressure chamber P is connected to the working port A and the working port B is connected to the return chamber R. Accordingly, the directional control valve 6 assumes a one-sided increase in the control pressure P _BX switch position 244, in which the pressure chamber P is connected to the working port B and the working port A to the return space R. Thus, these switching positions 240, 242, 244 allow the control of a double-acting consumer.

Upon actuation of the spool 8, 10 with a mean control pressure P _BX and a maximum control pressure P _AX , the directional control valve 6 assumes the middle position described in FIG. 8 (switch position 246) in which the working port A is shut off and the working port B is depressurized to the tank. By increasing the control pressure P _BX , the clearance position 248 can be reached, in which also the working port A to the tank depressurized (Figure 7). By reducing the control pressure P _BX , the switching position 250 can be achieved, in which the pressure chamber P is connected to the working port A. Although the switching position 250 basically corresponds to the switching position 242, but at a higher control pressure level P _AX . Since in the switching positions 246, 248, 250 of the working port B is always connected to the tank, 6 single-acting consumer can be controlled via the directional control valve.

With a corresponding mirror-inverted actuation of the directional control valve 6, ie, the control pressure P _XB is kept constant at maximum pressure and the control pressure P _AX is increased or decreased, the directional control valve 6 assumes switching positions 248, 252, 254 for controlling a simple acting consumer, in which Working port A always connected to the tank and the working port B is connected to the size of the control pressure P _AX with the pressure chamber P or the return space R.

The directional control valve 6 according to the invention allows both the Control single-acting as well as double-acting Consumer. Consequently, a variety of Applications. An example is the use the directional control valve 6 for pressure control of implements a tractor or hoists in construction machines, in which, for example, for lifting a cylinder side is pressurized and the other side of the cylinder relieved of pressure.

At the same time, the directional control valve 6 is, for example, suitable for "single - acting functions" in motor applications for free leakage or for position control in single-acting Cylinders.

Disclosed is a directional control valve with two in a slide bore Coaxial control slides for control a consumer via two working connections, wherein between the two spools a spring means is provided with a spring element whose Effective length is limited by means of a limitation.

LIST OF REFERENCE NUMBERS

2

LS system

4

Individual pressure compensator

6

way valve

8th

spool

10

spool

12

Pressure control valve

14

Pressure control valve

16

locking block

18

locking block

20

Pressure regulator piston

22

Pressure compensator bore

24

control collar

26

spring shackle

28

control edge

30

pressure chamber

32

pressure channel

34

control spring

36

spring chamber

38

first control channel

40

shuttle valve

42

control room

44

second control channel

46

damping throttle

48

channel

50

channel

52

slide bore

54

centering

56

centering

58

spring means

60

centering

62

centering

64

Control pressure chamber

66

Control pressure chamber

68

body

70

body

72

floor area

74

floor area

76

spring plate

78

spring plate

80

attack

82

drain space

84

drain space

86

relief chamber

88

relief chamber

90

leading space

92

Return Room

94

pressure chamber

96

pressure chamber

98

control collar

100

control collar

102

Flow control edge

104

Flow control edge

106

control collar

108

control collar

110

Inlet control edge

112

Inlet control edge

114

annulus

116

annulus

118

annulus

120

annulus

122

annulus

124

annulus

126

circumferential groove

128

circumferential groove

130

circumferential groove

132

circumferential groove

134

housing shoulder

136

blocking piston

138

blocking piston

140

drilling

142

drilling

144

valve seat

146

valve seat

148

lead chamber

150

working chamber

152

working chamber

154

Return chamber

156

pilot poppet

158

pilot poppet

160

pilot spring

162

pilot spring

164

pilot seat

166

pilot seat

168

head Start

170

head Start

172

topping

174

topping

176

piston rod

178

piston rod

180

Entsperrungsraum

182

Entsperrungsraum

184

connecting channel

186

connecting channel

188

intermediate channel

190

intermediate channel

192

control line

194

control line

196

control line

198

control line

200

spring element

202

pull bar

204

spring plate

206

spring plate

208

shoulder surface

210

shoulder surface

212

gap

214

tank bore

216

stepped bore

218

ring surface

220

face

222

reason

224

tank bore

226

traction body

228

traction body

230

end

232

end

234

inner circumferential groove

236

face

238

face

240

switch position

242

switch position

244

switch position

246

switch position

248

Free gear position

250

switch position

252

switch position

254

switch position

256

Gehäusschulter

258

control line

260

control line

Claims (14)

Directional control valve for controlling a consumer with two coaxially arranged control slides (8, 10), via the two connected to the consumer working ports (A, B) with a pressure chamber (P) or a return space (R) are connected, and biased in the home position are, between the spools (8, 10) a spring means (58) having a spring element (200) is arranged, characterized in that the spring means (58) has a limit for determining a maximum effective length of the spring element (200). Directional valve according to claim 1, wherein the limitation a pull rod (202) has, on the two spring plates (204, 206) are displaceably guided, respectively via the spring element (200) at least against one Shoulder surface (208, 210) of the pull rod (202) tensioned are. Directional valve according to claim 1, wherein the limitation has two tensile bodies (226, 228) whose end portions (230, 232) are hook-shaped and interlock, and those in their limit position the maximum length of the spring means (58) and so that the bias of the spring element ('200) determine. Directional valve according to claim 1, 2 or 3, wherein the Spring element (200) is a compression spring. Directional control valve according to claim 1, wherein the intermediate space between the two spools (8, 10), in to which the spring device (58) is received, for Tank is relieved of pressure. Directional valve according to claim 5, wherein tank bores (214, 224) for pressure relief of a gap (212) formed in the spools (8, 10) are. Directional valve according to one of the preceding claims, wherein between the two spools (8, 10), a stop (80) is formed, against which the spool (8, 10) can be brought into abutment position by application of maximum control pressure (P _AX , P _BX ) , Directional valve according to claim 7, wherein the stop (80) as a snap ring in a central box-side Inner circumferential groove (234) is formed. Directional valve according to claim 7 or 8, wherein the Working connections (A, B) in stop position of the Control slide (8, 10) connected to the return chamber (R) are. Directional valve according to claim 7, 8 or 9, wherein at one of the spool (8, 10) in stop position one control of the consumer over the second Spool (8, 10) is possible. Directional valve according to one of the preceding claims, between the working connections (A, B) and the slide bore (52) each have a releasable Blocking block (16, 18) is arranged, in the outflow direction lock and over imposition with one Switch unblock control pressure in downstream direction. Directional control valve according to claim 11, wherein the blocking blocks (16, 18) each have a topping piston (172, 174), which can be acted upon by the drain-side load pressure (Y _A , Y _B ). Directional valve according to one of the preceding claims, wherein the directional control valve (6) as an LS system (2) with an individual pressure balance (4) is. Directional valve according to one of the preceding claims, wherein the directional control valve (6) is a 6-position valve is.

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