WO2019134832A1

WO2019134832A1 - Hydraulic valve assembly

Info

Publication number: WO2019134832A1
Application number: PCT/EP2018/085873
Authority: WO
Inventors: Steffen Knapper
Original assignee: Robert Bosch Gmbh
Priority date: 2018-01-04
Filing date: 2018-12-19
Publication date: 2019-07-11
Also published as: WO2019134788A1; DE102018221288A1

Abstract

The invention relates to a hydraulic valve assembly for use within a hydraulic control block, i.e. a valve disc with a common housing for different valves. A disc-like valve housing has two parallel running contact surfaces as outer surfaces and a directional control valve bore, a return channel which is open at both contact surfaces and to which a first fluid channel that opens into the directional control valve bore leads, a first outer connection opening to which a second fluid channel that opens into the directional control valve bore on one side of the first fluid channel leads, and a second outer connection opening to which a third fluid channel that opens into the directional control valve bore on the other side of the first fluid channel leads. A feed channel opens into the directional control valve bore, and a control piston in the directional control valve bore can be moved out of a rest position into a first working position in one direction and into a second working position in the opposite direction. In order to use the same valve housing for a single-acting hydraulic load with an external return as for a double-acting load, the second outer connection opening is used as a return opening. The return channel is blocked from the other channels within the valve housing.

Description

The invention relates to a hydraulic valve arrangement for use within a hydraulic control block. The valve arrangement comprises a disk-like housing, which has as outer surfaces two mutually parallel contact surfaces and perpendicular to the contact surfaces extending end faces and in which a parallel to the contact surfaces extending directional control valve bore, one outside the directional valve bore perpendicular to the two contact surfaces extending and at both contact surfaces open return passage to which a opening into the directional control valve, first fluid channel leads, a first Au ßenanschlussöffnung, which is located in an end face and to the one to the first fluid channel and on one side in the Directional valve bore opening, second fluid channel leads, and a second external connection opening, which is also located in an end face and to a channel at a distance from the first fluid and on the other side in the directional control valve hole opening, third fluid channel leads, and a in the directional control valve hole flow the inlet channel are formed. The valve assembly further comprises a control piston, which is longitudinally movably guided in the directional control valve bore and is displaceable from a rest position in the one direction to a first working position and in the opposite direction to a second working position, wherein in the first work position second fluid channel connects to the inlet channel and the third fluid channel to the inlet channel shuts off and in the second working position the second fluid channel to the first fluid channel connects.

Such a valve arrangement in disk construction is known for example from DE 10 2009 034 616 A1. Typically, such a valve assembly is also referred to as a valve disk and includes a plurality of valves, for example a valve with a directional function, a valve for a flow control, a valve o- more valves with a pressure function, a valve or more valves with a load-holding function. Several such valve discs are used together with a terminal plate and an end plate to a hydraulic control block, with which a number of hydraulic consumers, such as hydraulic cylinders, are operated. These include double-acting hydrocycles, but also single-acting hydraulic cylinders, such as the hydraulic cylinders of a hoist on a tractor. If no attachment is mounted on such a hoist, very low load pressures result, which may be lower than the pressure in the general return flow path passing through a plurality of valve disks of the control block. The load pressures may be less than the pressure in the return fluid path, in particular, when it is acted upon by other valve discs with large fluid flows or when the returning fluid is filtered. If the hydraulic cylinders of the hoisting gear are connected to the general return when the lowering is required, the pressure conditions described may cause the hoist not to be lowered as desired, but to be lifted.

To avoid such behavior, it is known, for example from the data sheet RE 66130 / 01.2014 Bosch Rexroth AG, on the valve disc, with which the single-acting hydraulic cylinder of a hoist are operated to provide for these hydraulic cylinder own, external return, which is independent of the is through all the valve disks passing return fluid path. The valve disk is designed completely differently with a lifting module and a lowering module than the valve disks for double-acting hydraulic consumers.

The invention has for its object to further develop a hydraulic valve assembly with the features mentioned above such that the disc-like housing for the valve assembly for actuating a single-acting hydraulic consumer at least as a blank is the same as the disc-like housing for a double-acting hydraulic consumer and without can be further combined with another valve disc to form a control block. The valve arrangement should have an external return. This object is achieved in a hydraulic valve assembly having the features mentioned in the fact that the control piston shuts off in the second working position, the third fluid channel to the inlet channel that the control piston in the second working position, the third fluid channel connects to the first fluid channel and that the return channel and the first fluid channel are fluidly locked against each other. While in a hydraulic valve arrangement for a double-acting Flydrozylinder in the second working position of the control piston the leading to the second outer terminal, third fluid channel is connected to the inlet channel, the third fluid channel is in the valve assembly according to the invention in the second operating position of the control piston to - Shut off connection and connected via the control piston and the directional control valve bore to the first fluid channel. So that the external return and the internal return do not influence each other, the internal return channel and the first channel, which are still open to each other in the upper part of the housing and, if necessary, after a final machining of the housing, are locked against each other. However, the return channel in the valve disc for the single-acting hydraulic consumer or consumers is still open from abutment surface to abutment surface and a portion of the return fluid path passing through the control block.

If it is mentioned here of the first working position or second working position, as well as a proportional adjustment of the control piston should be included. With a proportional adjustment, the control piston has, so to speak, several first working positions and several second working positions, in which the operating direction of a connected hydraulic consumer is the same at different speeds.

A hydraulic valve arrangement according to the invention can be further configured in an advantageous manner.

In the return channel, a shut-off is inserted, through which the return channel and the first fluid channel are shut off from each other. Most preferably, the return passage is a bore into which a circular cylindrical sleeve is inserted, through which the return passage and the first fluid channel are shut off from each other. The bushing may be held in the return passage with a slight interference fit. In addition, it can be as long as the distance between the two contact surfaces of the disc-like housing, so that, when the drilled return channel has a slightly larger diameter than in the other valve discs, it is fixed by adjacent valve discs.

In many cases, hydraulic control blocks are designed as so-called load-sensing control blocks (LS or load-sensing control blocks), for the individual LS valve disks of which a control piston is used, which holds a metering orifice, via which a pressure drop is kept constant in conjunction with a pressure compensator and with which regardless of the load pressure and the pump pressure to a hydraulic consumer inflowing pressure fluid quantity and thus the speed of the hydraulic consumer are determined, and having a direction portion with which the direction of movement of the hy-rule consumer is determined. LS valve disks are known, in the housing of which a fourth fluid channel is formed, which, seen from the mouth of the first fluid channel in the directional valve bore, beyond the second fluid channel, a first mouth and beyond the third fluid channel a second Mouth has in the directional control valve hole. As in the case of the known LS valve disks, it is provided that the control piston has an inlet piston collar with an inlet control edge via which it connects the first mouth of the fourth fluid channel to the inlet channel in the first working position and wherein the control piston has another one Has piston collar with which it shuts off the second mouth of the fourth fluid channel in the first working position against the third fluid channel. In the second operating position, the control piston advantageously blocks the first opening of the fourth fluid channel with the inlet piston collar against the inlet channel. In the fourth fluid channel can thus not be pending the pump pressure. It is also advantageous if the control piston shuts off in the second operating position, the first mouth of the fourth fluid channel with a third piston collar against the second fluid channel and the third fluid channel to the second mouth of the fourth fluid channel is open. This is also not the load pressure in the fourth fluid channel, but in the fourth fluid channel prevails the same pressure as in th third fluid passage, so tank pressure. This is particularly advantageous because usually the pressure from the fourth fluid channel is fed into a shuttle valve chain, via which the highest load pressure of all simultaneously actuated hydraulic consumer is reported to an LS variable displacement or a fixed displacement pump associated with an input pressure compensator. The above connection and shut-off of the fourth fluid channel to the other fluid channels ensures that the shuttle valve chain does not report unnecessarily high pressure. The control piston may have a piston collar with which it shuts off the second fluid channel against the first fluid channel in the first work position. In itself, a shut-off of the second fluid channel against the tank in the first working position of the control piston can also be obtained by channeling the first fluid channel through a piston collar on the control piston against the third fluid channel. But then there is the full load pressure in the region of the first fluid channel.

The control piston can be displaceable beyond the second working position into a stop position, in which it shuts off the first fluid channel with a piston collar against the third fluid channel. Thus, a movement of a Hydrozylin- can be stopped even when the control piston, for example, because a span between a control edge of the control piston and a control edge of the housing is clamped, can not be reset to the neutral position. It can be provided that the control piston in the stop position the first fluid channel against the third fluid passage shuts off with the same piston collar, with in the first working position, it shuts off the second fluid channel against the first fluid channel.

The control of driving loads, for example, the lowering of a mounted on the hoist of a tractor implement usually takes place via a propor- tionally displaceable control edge on the control piston. Particularly at medium and higher load pressures, a typical throttling noise is produced with a frequency of, for example, 12 kHz. In the case of electrohydraulically pilot operated valves, in order to keep the static friction low, the so-called dither signal is often superimposed on the drive signal for the proportional electromagnet. This current oscillation impressed on the proportional electromagnet can propagate to it and thus to the pressure fluid flow and the pressure in the consumer port due to the large amplification between the pilot control and the control piston. This also causes noise.

In order to reduce the noise can be provided in a hydraulic valve according to the invention rule rule that the control piston a first return control edge, with a flow cross section between the second fluid channel and the first fluid channel is controllable, and a second return control edge, with a flow cross-section between the first fluid channel and the third fluid channel is controllable, and that the two return control edges are arranged in a channel from the second fluid channel via the first fluid channel to the third fluid channel leading fluid path and in the second operating position of the control piston at both Return control edges a flow cross section is open. Through this series connection, the pressure drop is divided into two control edges. This arrangement significantly reduces the overall noise.

It is favorable if the first return control edge on a piston collar and the second return control edge on another piston collar and if there is a piston neck between these two piston collars, in which the diameter of the control piston is smaller than the diameter of the directional control valve bore. Preferably, in the second working position of the control piston, the flow resistance at the first return control edge is the same as the flow resistance at the second return control edge. This can be achieved in that the two return control edges are of the same design and are opened in the same way. The pressure drop across the first return control edge is then equal to the pressure drop across the second return control edge and thus minimally over each return control edge. The return control edges may have fine control grooves. When the control piston is displaced in the direction of the second working positions, only flow cross sections at the fine control grooves are initially opened. If the control piston is moved far enough, a circulating flow cross-section is finally opened. However, it may also be that the control piston can only be displaced so far that hydraulic fluid only flows through the fine control grooves and no circulating flow cross section is opened.

In the second fluid channel, a pilot-operated check valve may be arranged, which operates in the direction of the directional control valve bore to the first outer port opening as a check valve and during a movement of the control piston in the second working position via a controlled by a run-on slope on the control piston actuating plunger unlocked. Usually, the arrangement is such that when lowering a load, the flow cross-section at the check valve is much larger than at the return control edges, so that essentially falls on this, the load pressure to tank pressure.

An exemplary embodiment of a hydraulic valve arrangement according to the invention designed as a valve disk is shown in the drawings. Based on these drawings, the invention will now be explained in more detail.

Show it

1 shows the embodiment in a perspective view, FIG. 2 shows a longitudinal section through the valve disk in a center plane extending parallel to the contact surfaces, the control piston being in a middle position, and

Figure 2 shows the same longitudinal section through the valve disc as in Figure 2, wherein the control piston is in a working position in which a load is lowered.

The illustrated hydraulic directional control valve arrangement, which is referred to below as a valve disc, has a disk-shaped valve housing 10 with two mutually parallel abutment surfaces 11, with which the valve disc can rest against further identical valve discs, to form a valve together with the other valve discs to form hydraulic control block. Perpendicular to the contact surfaces 11, the valve housing 10 has a series of end faces, namely essentially a top 12, in which a first external connection opening 13 and a second external connection opening 14 are located and from which a arranged between the two outer connection openings mounting hole 15, which by a Closure screw 16 is closed, a top side opposite the underside 17, pilot side 18, to which an electro-hydraulic pilot control unit 19 is attached, and a front side of the control side opposite fourth end 20th

Perpendicular to the contact surfaces 11, three bores 26 pass through the valve housing 10 and are provided for receiving tie rods with which the various valve disks of the control block are held against one another. The valve disc can be connected to a pump via a pump channel 27 which extends through the valve housing 10 perpendicular to the contact surfaces 11. Also perpendicular to the contact surfaces 11 passes through the valve housing 10, a return passage 28 of large cross section, can flow through the pressure fluid to a tank. A second continuous return channel 29 has a smaller cross-section. Finally, two smaller holes 30 and 31 also pass perpendicular to the contact surfaces 11. About the bore 30, the pilot unit is under pressure under a certain pressure fluid supplied while via the bore 31, a connection of the pilot unit to a tank.

The valve housing 10 has a continuous directional valve bore 35 with a central axis 36, in which a control piston 37 can be displaced in the direction of the central axis. At the fourth end face 20, the directional control valve bore 35 is closed by a locking screw 38. On the pilot control side 18, the control piston 37 projects out of the directional control valve bore 35 and is surrounded outside the valve housing 10 by two helical compression springs 39 and 40, by means of which the control piston is spring-centered in a central position, which is shown in FIG.

The directional control valve formed by the valve housing 10 and the control piston 37 is provided for actuating a single-acting hydraulic consumer (not shown), for example a lifting cylinder, on the lifting gear of a tractor.

Parallel to the directional control valve bore 35, a blind bore 41 is introduced from the fourth end face 20 forth in the valve housing 10, in which a control piston 42 and a control spring 43 of a pressure compensator 44 are housed and which is closed by a screw 44.

In the directional control valve bore 35 a number of spaced-apart annular chambers are formed. An inlet chamber 51 flows pressure fluid from the pump channel 27 via the control piston 42 of the pressure compensator 44 to. The inlet chamber 51 is followed by an intermediate chamber 52, which can be connected to the inlet chamber via a control edge on the control piston 37. The flow cross section between the inlet chamber 51 and the intermediate chamber 52 is different depending on how far the control piston is displaced from its central position to a first working position and forms a metering orifice, via which the pressure drop from the pressure compensator 44 is kept constant. The intermediate chamber 52 is followed by a connection chamber 53, from which a fluid path 54 leads to the first outer connection opening 13. In this fluid path 54 is a pilot-operated check valve 55 which is inserted into the mounting hole 15 and for a Lumenstrom of the chamber 53 to the external connection port 13 out as a check valve operates and can be unlocked to allow a flow in the reverse direction. This unlocking takes place via an actuating tappet 56, during an adjustment of the control piston 37 from the central position to a second working position at a starting bevel 57 of the control piston 37 runs up and is thereby displaced.

The connection chamber 53 is followed by a return chamber 58, from which a fluid channel 59 leads to the return channel 28. The return chamber 58 is followed by a second connection chamber 60, from which a fluid channel 61 leads to the second outer connection opening 14. Finally, the connection chamber 60 follows a further intermediate chamber 62, which is connected via an arc channel 63 to the first intermediate chamber 52. Of the arc channel 63 performs a stitch channel in the spring chamber of the pressure compensator 44, so that in the spring chamber the same pressure as in the intermediate chambers 52 and 62 and thus the pressure downstream of the measuring orifice. On the control piston 42 of the pressure compensator 44, a control edge 64 is formed, with which the control piston controls a flow cross-section between the pump channel 27 and one leading from the blind bore 41 to the inlet chamber 51 inlet channel 65. The control piston 42 is the pressure in the inflow channel 65 and in the feed chamber 51 and thus from the pressure upstream of the orifice in the direction of reduction and the pressure downstream of the orifice and the force of the control spring 43 in the direction of increasing He controlled flow cross-section. By the pressure compensator is so upstream of the

Metering orifice regulated in each case a pressure which is the pressure equivalent of the control spring 43 above the pressure in the bottom channel 63, so that the pressure drop across the metering orifice in each case corresponds to the pressure equivalent of the control spring and thus is constant.

Between the shut-off valve 55 and the outer connection opening 13, a pressure-suction valve 66 is connected to the fluid path 54, which is connected to a return line. channel 29 is introduced and introduced from the fourth end face in the valve housing 10 blind bore.

The electrohydraulic pilot control unit 19 has a proportionally adjustable pressure control valve 70 with Doppelhubmagneten 71, a displacement sensor 72, with which the position of the control piston 37 can be detected, an electrical connector 73 for powering the pilot unit and for specifying a desired signal for the position of the control piston and a circuit board 74th via which the displacement sensor, electromagnet and electrical plug are connected to one another and which carries electronic components for a control loop for the position of the control piston 37.

As far as described so far, the valve disk is also suitable for actuating with it a double-acting hydraulic consumer, for example a double-acting hydraulic cylinder. According to the invention, the same valve housing 10 can now be used for the actuation of a single-acting hydraulic consumer, wherein an external return, namely a return via the second external connection opening 14, is additionally provided. For this purpose, a bushing 75 is only pressed into the return channel 28, which is as long as the distance between the two contact surfaces 11 of the valve housing 10 and through which the return channel 28 and the fluid channel 59 are shut off from each other. Thus, although the return duct 28 passes through the valve disk shown, it can no longer be used for the control of the hydraulic consumer assigned to the valve disk. Rather, due to a special design of the valve disc provided for the control piston 37 of the fluid channel 61 and the Außenanschlussöff- 14 tion the return and that an external return of the valve disc. For this purpose, the connection opening 14 is connected to a tank. The control piston 37 has a piston collar or control collar 77, with a single circumferential control edge 78, through which in the middle position of the control piston 37 shown in Figure 2, the inlet chamber 51 against the intermediate chambers 52 and 62 is shut off and can be described as Zulaufkolbenbund.

The control piston 37 has a further control collar 79, with which in the middle position of the control piston 37, the connection chamber 53 is shut off against the intermediate chamber 52. The control piston 37 has a further control collar 80, on which a plurality of fine control grooves 81 are formed and with which in the middle position of the control piston 37, the connection chamber 53 is shut off against the return chamber 58. The control piston 37 has a further control collar 82, on which a plurality of fine control grooves 83 are formed and with the in the middle position of the control piston 37, the return chamber 58 is shut off against the connection chamber 60. The fine control grooves 81 in their entirety form a first return control edge and the fine control grooves 83 in their entirety form a second return control edge. The control piston 37 has a further control collar 84, with which in the middle position of the control piston 37, the connection chamber 60 is shut off against the intermediate chamber 62.

If now the control piston 37 is displaced from the middle position in the direction of the closure screw 38 to a first working position, the control edge on the control collar 77 opens a flow cross-section from the inlet chamber 51 to the intermediate chamber 52. The control collar 79, which in FIG Direction of the central axis 36 is shorter than the intermediate chamber 52 is completely in the range of this intermediate chamber and thus opens it to the connection chamber 53. The control collar 80 also blocks the connection chamber 53 against the return chamber 58 and the control collar 84 continues to block the connection chamber 60 against the intermediate chamber 62 from. Whether the control collar 82 still blocks the chambers 58 and 60 against each other or not is irrelevant. Pressure fluid now flows from the pump channel 27 via the pressure compensator 44, the inlet channel 65, the inlet chamber 51, the intermediate chamber 52, the consumer chamber 53 and the fluid path 54 to the external connection opening 13 and from there to a single-acting hydraulic consumer.

If the control piston is moved from the middle position shown in FIG. 2 away from the closure screw 38 into a second working position shown in FIG. 3, Thus, the actuating plunger 56 runs on the run-on slope 57 so that it is moved in the direction of the check valve 55 and the check valve is opened. In the second operating position of the control piston 37, as in the middle position of the control piston 37, the inlet chamber 51 and the connection chamber 53 continue to be shut off against the intermediate chamber 51. The connection chamber 60 is open to the intermediate chamber 62 and thus to the arc channel 63 and to the intermediate chamber 52. A flow cross section between the connection chamber 53 and the return chamber 58 is opened via the fine control grooves 81 on the control collar 80. Furthermore, a flow cross-section between the return chamber 58 and the connection chamber 60 is opened via the fine control grooves 83 on the control collar 82. Thus, hydraulic fluid flows from under the action of a load hydraulic consumers via the external connection port 13, the fluid channel 54 with the open check valve 55, via the connection chamber 53, via the fine control grooves 81, via the return chamber 58, via the Feinsteuernu- th 83, over the connection chamber 60 and the fluid channel 61 to the second external connection port 14 and from there to a tank. The path from the return chamber 58 into the tank channel 28 is blocked by the pressure fluid through the sleeve 75 inserted into the tank channel 28. Thus, between the outer connection chamber 53 and the outer connection chamber 60 there are two flow cross sections which throttle the liquid flow, namely the flow cross section at the fine control grooves 81 and the flow cross section at the fine control grooves 83 in series one after the other. The flow cross section at the fine control grooves 81 is selected equal to the flow cross section at the fine control grooves 83. Thus, the pressure drop over the one flow cross section is just as great as over the other flow cross section. The flow cross section at the check valve is substantially larger than the flow cross sections at the control cylinders 80 and 82, so that almost the load pressure is present in the connection chamber 53. The pressure drop across the two throttling flow cross sections is thus almost equal to half the load pressure. The total pressure drop is thus divided over two control edges, whereby the throttling noise is low. The series connection of similar control edges leads to a lower gain on the control piston. This significantly reduces the noise caused by the dithering vibration.

If the control piston 37 is moved away from the closure screw 38 beyond the second working positions, then the fluid communication between the return chamber 58 and the connection chamber 60 is interrupted by the control collar 80, so that no pressure fluid is present even when the blocking valve 55 is kept open from the connection opening 13 to the connection opening 14 can flow. The movement of a hydraulic consumer can thus be stopped even if, for some reason, the control piston 37 can not be returned to the middle position from a second operating position. The electromagnet 71 must then be heavily energized and remain energized.

LIST OF REFERENCE NUMBERS

10 valve housing

1 1 contact surfaces of 10

12 top of 10

13 first external connection opening in 12

14 second external connection opening in 12

15 mounting hole

16 screw plug

17 bottom of 10

18 input side of 10

19 electrohydraulic pilot control unit

20 fourth face of 10

26 holes

27 pump channel

28 return channel

29 return channel

30 hole

31 hole

35 directional control valve bore

36 central axis of 35

37 control piston

38 screw plug

39 helical compression spring

40 helical compression spring

41 blind hole

42 control pistons of 44

43 control spring of 44

44 pressure balance

51 inlet chamber in 35

52 intermediate chamber in 35

53 connection chamber 54 fluid path from 53 to 13

55 unlockable check valve

56 actuating tappet

57 starting slope on 37

58 return chamber

59 fluid channel from 58 to 28

60 connection chamber

61 fluid channel

62 more intermediate chamber 63 arch channel between 62 and 52nd

64 control edge on 42

65 inlet channel

66 pressure suction valve

70 pressure control valve

71 double-stroke magnet

72 encoder

73 electrical connector

74 circuit board

75 socket

77 tax code to 37

78 control edge on 77

79 tax code to 37

80 tax code to 37

81 fine control grooves on 80

82 tax code to 37

83 fine control grooves on 82

84 tax code to 37

Claims

claims

1. Hydraulic valve arrangement for use within a hydraulic control block with a disk-like housing (10), which as outer surfaces two mutually parallel contact surfaces (11) and perpendicular to the contact surfaces (11) extending end faces (12, 17, 18, 20) and in which a parallel to the contact surfaces (11) extending directional control valve bore (35), outside the directional control valve bore (35) perpendicular to the two contact surfaces (11) extending and on both contact surfaces (11) open return channel (28), to a first external connection opening (13), which is located in an end face (12) and to the one at a distance from the first fluid channel (59) and on the one side in the directional control valve bore (35) opening, second fluid duct (54) leads, and a second outer connection opening (14), which also in an end face (12) and located to the one at a distance to the first fluid passage (59) and on the other side in the directional control valve bore (35) opening, third fluid channel (61) leads, and in the directional control valve bore (35) opening out inlet channel (65) are formed, and with a control piston (37), which is longitudinally guided in the directional control valve bore (35) and is displaceable from a rest position in one direction to a first working position and in the opposite direction to a second working position, wherein it is in the first Working position, the second fluid channel (54) connects to the inlet channel (65) and the third fluid channel (61) to the inlet channel (65) shuts off and in the second working position the second fluid channel (54) with the first fluid channel (59) connects,

characterized,

that the control piston (37) shuts off the third fluid channel (61) to the inlet channel (65) in the second working position, that the control piston (37) in the second working position the third fluid channel (61) with the first fluid channel ( 58) and that the return channel (28) and the first fluid channel (59) are fluidically shut off from each other.

2. Hydraulic valve arrangement according to claim 1, wherein in the return passage (28) a shut-off member (75) is inserted, through which the return passage (28) and the first fluid channel (59) are shut off from each other.

3. A hydraulic valve arrangement according to claim 2, wherein the return passage (28) is a bore and wherein in the return passage (28) a circular-cylindrical bush (75) is inserted through which the return passage (28) and the first fluid channel ( 59) are locked against each other.

4. Hydraulic valve arrangement according to a preceding patent claim, wherein in the housing (10) a fourth fluid channel (63) is formed, which, from the mouth of the first fluid channel (59) in the directional control valve bore (35) seen from on the other side of the second fluid channel (54) has a first mouth and beyond the third fluid channel (61) has a second opening in the directional control valve bore (35), and wherein the control piston (37) has an inlet piston collar (77) with an inlet control edge, via which it connects in the first working position, the first mouth of the fourth fluid channel (63) with the inlet channel (65) and wherein the control piston (37) has a further piston collar (84), with which he in the first working position, the second Mouth of the fourth fluid channel (63) against the third fluid channel (61) shuts off.

5. Hydraulic valve arrangement according to claim 4, wherein the control piston (37) in the second working position, the first mouth of the fourth fluid channel (63) with the inlet piston collar (77) against the inlet channel (65) shuts off.

6. Hydraulic valve arrangement according to claim 5, wherein the control piston (37) in the second working position, the first mouth of the fourth fluid channel (63) with a third piston collar (79) against the second fluid duct (54) shuts off and the third fluid channel (61) to the second mouth of the fourth fluid channel (63) is open.

7. Hydraulic valve arrangement according to a preceding patent entitlement, wherein the control piston (37) has a piston collar (80) with which it shuts off the second fluid channel (54) in the first working position against the first fluid (58).

8. Hydraulic valve arrangement according to a preceding patent entitlement, wherein the control piston (37) beyond the second working position is displaceable into a stop position in which he channel with a piston (80) the first fluid (59) against the third fluid ( 61) shut off.

9. Hydraulic valve arrangement according to claims 7 and 8, wherein the control piston (37) in the stop position the first fluid channel (59) against the third fluid channel (61) with the same piston collar (80) shuts off, with which he in the first working position the second fluid channel (54) against the first fluid channel (59) shuts off.

10. Hydraulic valve arrangement according to a preceding patent entitlement, wherein the control piston (37) has a piston collar (82) with which it in the first working position the first fluid channel (59) against the third fluid channel (61) shuts off.

11. Hydraulic valve arrangement according to a preceding patent claim, wherein the control piston (37) a first return control edge (81), with a flow cross section between the second fluid channel (54) and the first fluid channel (59) is controllable, and a second Return control edge (83), with which a flow cross section between the first fluid channel (59) and the third fluid channel (61) is controllable, and wherein the two return control edges (81, 83) in series in one of the second fluid channel (54) via the first fluid channel (59) to the third fluid channel (61) leading fluid path are arranged and in the second working position of the control piston (37) at both return control edges (81, 83), a flow cross-section is open.

12. The hydraulic valve assembly of claim 11, wherein the first return control edge (81) on a piston collar (80) and the second return control edge (83) on another, from the piston collar (80) with the first return control edge (81) spaced piston collar (82) of the control piston (37) is located.

13. A hydraulic valve assembly according to claim 11 or 12, wherein in the second working position of the control piston (37) of the flow resistance at the first return control edge (81) is the same as the flow resistance at the second return control edge (83).

14. A hydraulic valve assembly according to claim 11, 12 or 13, wherein the return control edges Feinsteuernuten (81, 83) or by Feinsteuernuten (81, 83) are formed.

15. Hydraulic valve arrangement according to a preceding patent claim, wherein in the second fluid channel (54) a pilot-lock valve (55) is arranged, which works in the direction of the directional control valve bore (35) to the first external port (13) as a check valve and during a movement of the control piston (37) in the second working position via a by means of a run-on slope (57) on the control piston (37) controlled Betätigungsstö- tappet (56) is unlocked.