DE19715020A1 - Hydraulic control system for transporting vehicle, especially sedimentation vessels - Google Patents

Abstract

The system has a selector valve with control plunger (22) sliding axially in a bore (21) in a valve housing (20). This controls the passages between an inlet chamber (27) supplied by a hydraulic pump, an outlet chamber (32,33) connected to a tank, and a consumer chamber (28,29), the latter being incorporated in the supply or return passage of a hydraulic consumer unit. A throttle valve has a plunger (66) sliding axially in a bore (61) in the valve housing. This varies the flow-resistance between an inlet passage (65) supplied by the pump and an outlet passage (64) from the throttle-valve bore to the inlet chamber (27). This causes sliding in one direction under load pressure from the consumer unit and which is fed to a load-sensing regulator.

Description

The invention is based on a hydraulic control arrangement, which in particular for a vehicle for transporting skip which should be used and which the characteristics from the Oberbe handle of claim 1.

Such a hydraulic control arrangement is from the prospectus 9129 8557-02 (GB) from VOAC Hydraulics AB, Boras, Schwe the, known. In this brochure directional valves in Schei benbaubau presented for use in the Mobilhy draulic are provided and by the stringing of individual valve disks to control blocks for the control A large number of hydraulic consumers are assembled that can. A valve disc contains a directional valve and a Throttle valve. To accommodate the moving parts of this venti le, the valve housing of a valve disc has a directional control valve bore in which a directional control piston is axially displaceable is with which the pressure medium paths between different around the Directional valve bore running around and open to this Ka channels are controllable. They are an inlet channel, the pressure inflows medium from a hydraulic pump, two discharge channels, via the pressure medium flows to a tank and two consumer ka channels available that lead to a dop in the forward or reverse pelt-acting hydraulic consumers.

The throttle valve has a throttle piston which is in a Throttle valve bore is axially displaceable, which is parallel to Directional valve bore runs. There is one over the throttle piston Connection with different choke resistances between an input channel to the pressure medium from the hydraulic pump flows, and an output channel of the throttle valve bore, the is connected to the inlet channel of the directional valve bore  adjustable. In the sense of a shift in one direction the throttle piston from the load pressure of the with the directional control piston controllable hydraulic consumer. In the Valve arrangement according to the brochure is a Load-sensing valve arrangement in which the directional control piston propor tionally adjustable and depending on the extent of its displacement from a middle position between the inlet channel and a Consumer channel a measuring aperture different opening cross opens up. The throttle valve is egg ne upstream of the orifice, which is independent of the Pumps in the inlet channel of the throttle valve bore print a certain pressure difference across the orifice plate should maintain. Therefore, the throttle piston is against that Sense of movement in which the load pressure and a spring on it act, acted upon by the pressure upstream of the orifice plate.

Are not such high demands on the control of a hydrau posed consumer, but this should still with different speeds can be operated, so is not proportional speed control with a variable orifice plate necessary. Rather, it is sufficient if in a flow path leading to the hydraulic consumer in Series for the directional valve, different sized fixed orifices can be tet. In this way, several Ge Realize speed levels. A hydraulic control order of this kind is z. B. known from DE 42 09 472 A1. There is in addition to a directional valve, with the start and Stop and the direction of movement of a hydraulic consumption chers can be specified, another directional valve existing the one with which different fixed fades in between the ways valve and the hydraulic consumer can be switched.

The invention has for its object a hydraulic Control arrangement with the features from the preamble of the An say 1 with little effort to change so that with the  Directional valve controllable hydraulic consumers in two ge speed levels can be moved.

The desired goal is according to the invention at a hydrau Control arrangement with the features from the preamble of claim 1 according to the characterizing part of this claim achieved in that the throttle piston arbitrarily against the Load pressure from a first position to a second position is displaceable in the throttle resistance of the connection differentiated between the input channel and the output channel Lich to the throttle resistance of the connection in the first Position is. In a hydraulic control arrangement according to the So invention is with respect to the cavities of the valve housing, in which the load pressure of the hydraulic consumer is present can, no change compared to the known valve necessary. The load pressure continues to act in one direction on the Throttle piston. However, there is a change in the force application the throttle piston in the opposite direction. While at the known valve in a second control chamber of the throttle piston keeps the pressure upstream during operation changeable orifice is present, can now against the load pressure an arbitrary force is exerted on the throttle piston through which the throttle piston is adjusted against the load pressure that can. In the event of elimination or a sufficiently large reduction, the force, the load pressure can return the throttle piston put.

Advantageous configurations of a hydraulic system according to the invention rule can be found in the subclaims.

According to claim 2, the throttle piston is preferably pilot-controlled. For this purpose, the load pressure is adjacent to it beatable control room provided a second control room, the depending on the position of an arbitrarily operated pilot valve can be acted upon with a control pressure or discharge from pressure can be steady. As with a hydraulic load sensing control  at least as long as there is no undersaturation, the pump pressure by at least a predetermined pressure difference is above the load pressure of the hydraulic consumer According to claim 3, the pump pressure preferably ver as control pressure turns.

So that the throttle piston can be switched safely, even if in In view of a simple design load pressure and pumps Apply equal pressure to the throttle piston, the Dros selkolben therefore has no gradation.

According to claim 6, the throttle piston is rich in load pressure to a position with a small throttle resistance between the input channel and the output channel of the throttle valve boh actionable. It is assumed that the hy Draulic consumers are usually on the bulk nes way is moved at high speed, so that Do not apply any force to the throttle piston during this partial route must put him against the load pressure in the position for the higher Bring speed level and should stop there. At a hydraulic actuation of the throttle piston using a Pi solder valve then takes this according to claim 7 under the effect a spring in the position in which the second control chamber on Throttle piston is relieved of pressure. Will the pilot valve by actuated an electromagnet, the electromagnet only has to be energized for a short time.

So that the throttle piston at the start of actuation of the hydrau consumer, usually with high speed speed, he holds a certain position according to claim 8 in the same direction of action as the load pressure spring loaded. Thus, the throttle piston must Commissioning must not be adjusted by the load pressure.

If one with two switch positions of the throttle piston two Ge want to realize speed levels, so there is no further  Precautions in both switching positions of the throttle piston one open connection between the input channel of the throttle valve bore and the inlet channel of the directional valve bore. When opening the control cross section between the inlet channel and the Ver user channel of the directional control valve there is then the risk that the Load sags because the load-sensing controller still has the pump pressure has not increased above the load pressure. According to claim 10 a load holding valve is now provided to prevent the To prevent load. For a space-saving accommodation of this The throttle piston is a hollow piston with a load holding valve Cavity through which in the under the effect of the load pressure assumed position of the throttle piston a flow path from Input channel leads to the output channel of the throttle valve bore and in which the closing member of a load holding valve is arranged is, the closing member in the closing direction of the load pressure is acted upon. The closing element of the load holding valve is advantageously acted upon by a spring in the closing direction strikes so that it assumes a closed rest position. The The spring is preferably based on a housing fixed abutment. This simplifies the effort because the Dros selkolben no abutment for the spring must be formed. The spring can at the same time on the closing member of the load holding device tils towards a rest position on the throttle piston we ken.

Two embodiments of a hydraulic according to the invention Control arrangement are shown in the drawings. Based these drawings, the invention will now be explained in more detail.

Show it

Fig. 1 is a circuit diagram of the configured as a control block having a plurality of valve discs first execution example,

Fig. 2 is a longitudinal section through a valve disk of the first embodiment which contains a directional valve and a throttle valve with a switchable throttle piston for actuating a hydraulic consumer with two speeds,

Fig. 3 is a circuit diagram of the second embodiment, in which the pilot valve is not on the side of the valve housing, but sits on the narrow side opposite the consumer connections, and

Fig. 4 shows a section similar to that of Fig. 2 through the second embodiment, only the area of the throttle valve and the attached pilot valve is shown.

According to Fig. 1, a fixed displacement pump 10 sucks pressure fluid from a tank 11 and delivers it into a feed line 12 which leads to ei nem control block 13 and passes through a plurality of valve discs, of which the control block is composed. The feed line 12 enters the control block 13 at an input disc 14 . This is followed by a directional valve disc 15 with a directional valve and an individual pressure compensator and a directional valve disc 16 with a directional valve 8 and a switchable throttle valve 9 . Then follows a disk 17 with valves for the control oil supply of the electrohydraulically actuated directional control valves of the directional control valve disks 15 and 16 and with a pilot valve 93 . The feed line 12 continues in the individual valve disks as an inlet channel which runs in the valve disks perpendicular to the disk levels. A tank line 18 continues in the valve disks in the form of two tank channels.

The directional valve disk 16 is shown in more detail in FIG. 2. It can be seen that it has a valve housing 20 through which a directional valve bore 21 passes, in which a directional control piston 22 is axially movable. The length of the directional control piston 22 corresponds to the length of the directional valve bore 21 from one end face 23 to the other end face 24 of the valve housing 20 . The directional control valve bore 21 is surrounded by five axially spaced-apart control chambers which serve the inflow of pressure medium to and the outflow from the cylinder 25 and the connections between which are controlled by the directional control piston 22 . The middle of the five control chambers is the inlet chamber 27 . On both sides of this inlet chamber there is a consumer chamber 28 or 29 , each of which is connected to a consumer connection lying in a consumer channel 26 circuit 30 or 31 of the directional valve disk 16 . Each consumer chamber 28 and 29 is followed by an outlet chamber 32 and 33 which is open to a tank channel 18 going through the valve housing 20 .

The directional control piston 22 assumes a central position due to two centering springs 34 , which are accommodated in covers 38 fastened to the end faces 23 and 24 of the valve housing 20 and closing the directional valve bore 21 to the outside, from which it is adjusted as far as each actuation is concerned. that it strikes an adjustable stroke limiter 35 . In this middle position, two piston collars 39 of the directional control piston 22 , between which there is a piston neck 40 in the region of the inlet chamber 27 and which have open control grooves 36 towards the piston neck 40 , shut off the two consumer chambers 28 and 29 against the inlet chamber. However, it is the consumer chamber 28 via the annular space around a further piston neck 41 around the drain chamber 32 and the consumer chamber 29 via an annular space around a piston neck 42 around the drain chamber 33 . At the piston neck 42 there is a wide piston collar 43 , which seals the spring chamber in the one cover 38 against the drain chamber 33 .

The distance between the drain chamber 32 and the end face 23 is greater than the distance between the drain chamber 33 and the end face 24 of the valve housing. Between the discharge chamber 32 and the end face 23 there are three control chambers 44 , 45 and 46 , axially spaced apart from one another, in the directional valve bore 21 , the middle of these three chambers being referred to as the load reporting chamber 45 . To which, from the load-sensing chamber 45, endeavors to the front side 23 of the valve housing 20 lying control chamber 44 , the input of a pressure relief valve can be connected.

A pressure relief valve can also be connected to the control chamber 46 lying between the load-sensing chamber 45 and the drain chamber 32 . However, neither is the case here. Rather, the corresponding openings for the pressure relief valves are closed by plugs 47 . In the central position of the directional control piston 22, a piston collar 48 extends from the end face 23 of the valve housing 20 into the region of the housing web between the control chamber 46 and the drain chamber 32 . A flat annular groove 49 is screwed into this piston collar, via which all three control chambers 44 , 45 and 46 are connected to one another in the central position of the control slide 22 shown. In addition, the piston collar 48 has on its outer edge facing the drain chamber 32 a Einker exercise 50 through which the control chamber 46 and the drain chamber 32 are open to each other with a small opening cross-section when the directional control piston 22 is in its central position. If the directional control piston 22 is moved out of its central position, the load reporting chamber 45 is separated from the control chamber 44 or from the control chamber 46 , depending on the direction of movement of the directional control piston. In addition, regardless of the direction of movement Be the existing in the central position of the directional control piston 22 via the control chamber 46 connection of the Lastmel decammer 45 to the drain chamber 32 by the Lastmel decammer 45 from the control chamber 46 or the control chamber 46 is separated from the drain chamber 32 .

A closed blind bore 55 extends from the end face on the piston collar 43 through the directional control piston 22 into the region of the annular groove 49 . It is crossed by two transverse bores 56 , one of which is located in a piston collar 39 of the directional control piston 22 at a location such that it is covered by the wall of the directional control valve bore 21 in the central position of the directional control piston 22 . During a movement of the directional control piston from the central position in the one direction the one cross-bore 56 to the load chamber 28 to and during a movement of the control slide in the other direction the other transverse bore 56 open to the consumer chamber 29th Via a transverse bore 57 , which is introduced in the region of the annular groove 49 up to the blind bore 55 in the directional control piston 22 , the blind bore 55 is connected to the load-sensing chamber 45 .

From the end face 24 of the valve housing 20, a throttle valve bore 61 is introduced into this parallel to the directional valve bore 21 , which extends axially into the area of the control chamber 46 of the directional valve bore 21 and into which in the vicinity of its bottom 68 an outgoing from the load-sensing chamber 45 housing housed channel 62 opens. The throttle valve bore 61 is closed to the outside by a screw plug 63 . Axially opposite the inlet chamber 27 of the directional control valve bore 21 slightly offset befin det in the throttle bore 61, an output chamber 64 which is open to the inlet chamber 27 of the directional control valve bore 21st At a distance from the outlet chamber 64 there is an inlet chamber 65 between the latter and the screw plug 63 , which is connected to the inlet channel 12 .

In the throttle valve bore 61 , the throttle piston 66 of the throttle valve 9 is axial between a first switching position, which it assumes in the rest position and in which it rests on the screw plug 63 , and a second switching position, in which it is pressed against the bottom 68 of the throttle valve bore 61 slidable. The throttle piston 66 is designed as a hollow piston into which an axial blind bore 67 is made from the end face facing away from the screw plug 63 . A first transverse bore 69 passes through the wall thereof and is open to the input chamber 65 in both switching positions of the throttle piston 66 and represents a diaphragm with an opening cross section corresponding to the bore cross section. At a slightly greater distance from the bottom of the blind bore 67 than the transverse bore 69 go through the wall of the blind bore 67 four evenly distributed around the circumference of the throttle piston Querboh stanchions 70 , each of which is as large as the transverse bore 69 and in the first Switch position of the throttle piston 66 are also open to the input chamber 65 . At an even greater distance from the bottom of the blind bore 67 go through the wall four further transverse bores 71 , which are larger in diameter than the transverse bores 69 and 70 and which are in the most switching position of the throttle piston 66 completely and partially in the second switching position to the exit chamber 64 are open.

In the blind bore 67 of the throttle piston 66 , the closing member 75 , designed as a piston, of a load holding valve 76 can be axially displaced in a tightly sliding manner. Between the closing member 75 and the bottom 68 of the throttle valve bore 61 , a helical compression spring 77 is clamped, which the closing member 75 with a finger 78 , which is much smaller in diameter than the blind bore 67 , tries to press against the bottom of this blind bore. In a position of the closing member 75 in which it acts on the bottom of the blind bore 67 , there is a control edge 79 of the closing member 75 between the transverse bores 70 and 71 of the throttle piston 66 . Thus, in this position of the closing member 75 there is no fluidic connection between the inlet chamber 65 and the outlet chamber 64 of the throttle valve bore 61 .

The control arrangements shown are load sensing controlled. The highest load pressure is reported to a load sensing controller. This is done via a shuttle valve 79 in each directional valve disk 15 and 16 . The shuttle valve 79 of the We geventilscheibe 16 is built from the consumer connections 30 and 31 opposite narrow side 80 in the Ventilge housing 20 . An input of this shuttle valve is connected to the space 74 in which the helical compression spring 77 is located. The other entrance is at the tank. The output of the shuttle valve 79 is connected to an input of the corresponding shuttle valve of the directional valve disc 15 . About the shuttle valves, the load pressure of a hydraulic consumer or the highest load pressure of several simultaneously actuated hydraulic consumers in the input disk 14 is detected.

To shift the directional control piston 22 from its central position into a lateral end position, a spring chamber in one of the two covers 38 is acted upon by a control pressure. For this purpose, the two electromagnetically actuated pilot valves 81 and 82 , which are inserted into a cover 38 .

As can be seen from Fig. 1, the two pilot valves 81 and 82 in their rest position connect the two spring chambers in the covers 38 with a drain line 83 , while in a switched position of a pilot valve a spring chamber is connected to a control pressure line 84 . The control oil is provided by a pressure reducing valve 85 , the input of which is connected to the inlet channel 12 and at the output of which the control pressure line 84 is connected. The pressure reducing valve 85 be found in the valve disk 17 , in which the United connection between an input of the shuttle valve 79 of the directional valve disk 16 and a tank channel 18 is made.

The input disk 14 contains a bypass pressure compensator 90 which is connected with its inlet to the inlet channel 12 and with its outlet to the tank channel 18 . The regulating piston 91 of the pressure compensator 90 is acted upon in the opening direction by the pressure in the inlet channel 12 and in the closing direction by a compression spring 92 and by the load pressure of an actuated consumer or by the highest load pressure of several actuated consumers. You just can as much of the fixed displacement pump 10 funded pressure medium drain that the pressure in the supply line 12 to one of the force of the compression spring 92 equivalent pressure differential is greater than the acting in the closing direction of the control piston 91 load pressure from the inlet channel 12 into the tank channel 18th The Druckwaa ge 90 represents the load sensing controller already mentioned.

Instead of a constant pump with bypass pressure compensator, you can also a variable displacement pump with load sensing controller can be used.

If no directional control valve is actuated, the pump 10 promotes bei with a low, by the compression spring 92 of the pressure compensator 90 be circulating pressure of z. B. 20 bar pressure medium via the pressure compensator 90 to the tank.

The pressure of 20 bar in the inlet line and in the inlet channel 12 is also in the input chamber 65 of the throttle valve bore 61 of the directional valve disk 16 and via the transverse bores 69 and 70 of the throttle piston 66 in front of the closing member 75 of the load holding valve 76 . On the back of the closing member there is tank pressure, since the spring chamber 74 via the channel 62 , the Lastmeldekam mer 45 , the control chamber 46 , the notch 50 in the way control piston 22 and the drain chamber 32 to the tank channel 18 is relieved. Since the helical compression spring 77 is relatively weak, the closing member 75 is pressed by the circulation pressure against the compression spring 77 in the direction of the bottom 68 of the throttle valve bore 61 . The output chamber 64 is thus connected to the input chamber 65 of the throttle valve bore 61 , so that the circulation pressure is also in the inlet chamber 27 of the directional valve bore 21 .

It is now assumed that the piston rod of the cylinder 25 is to be extended. The directional control piston 22 is therefore shifted ben from its central position up to a stroke limiter 35 that the consumer chamber 28 is connected to the inlet chamber 27 . Via a transverse bore 56 , the axial bore 55 and the transverse bore 57 of the directional control piston 22 , the load pressure reaches the load reporting chamber 45 , the channel 62 and the spring chamber 74 at the bottom 68 of the throttle valve bore 61 . It is reported to the bypass pressure compensator 90 via the shuttle valves 79 .

The load pressure presses the closing member 75 of the load-holding valve 76 initially deeper into the blind bore 67 of the choke piston 66 inside so that the output chamber 64 and inlet chamber 65 of the throttle valve bore 61 are separated from each other. The pressure balance 90 finally regulates a pump pressure which is above the load pressure by the control Δp, in the present case by 20 bar. The load holding valve is then open and pressure medium flows from the input chamber 65 via the transverse bores 69 , 70 and 71 of the throttle piston 66 into the inlet chamber 27 of the directional control valve and from there via control grooves 36 of the way control piston 22 into the consumer chamber 28 and finally into the hydraulic cylinder 25th The flow resistance through the Dros selkolben 66 is only low, so that a large amount of pressure medium flows and the piston rod of the hydraulic cylinder 25 extends at high speed. This speed can be changed by adjusting the stroke limiter 35 , since the control valves 36 of the directional control piston 22 substantially determine the speed and, by changing the stroke of the travel control piston 22 , the position of the control grooves 36 and the opening cross section determined by them between the inlet chamber 27 and the consumer chamber 28 is changed.

If the piston rod of the hydraulic cylinder is to extend at low speed, the throttle piston 66 is brought hydraulically into its second switching position. For this purpose, a pilot valve 93 is present, which is designed as a 3/2-way valve and is built into the disk 17 in the embodiment according to FIGS. 1 and 2. In its rest position, which it assumes under the action of a compression spring 94 , it connects a pressure chamber 95 located between the throttle piston 66 and the locking screw 63 via a channel 96 which runs perpendicular to the plane of the valve disk 16 and thus parallel to the channels 12 and 18 , with the tank channel 18 . The throttle piston 66 can then assume the first switching position shown in FIG. 2 under the action of the compression spring 77 and under the action of the load pressure. The pilot valve 93 can be brought into a second switching position by actuating an electroma 97 , in which it connects the pressure chamber 95 to the inlet channel 12 . Since the pump pressure prevailing in the inlet channel 12 is in each case above the load pressure by the control Δp, the throttle piston 66 is brought into its second switching position by the pump pressure present in the pressure chamber 95 . In this, the transverse bores 70 are covered by the housing web located between the input chamber 65 and the output chamber 64 of the throttle valve bore 61 . The cross bores 71 are partially covered. The now significantly determined by the cross section of the transverse bore 69 hy draulic resistance of the flow path between the input chamber 65 and the output chamber 64 of the Drosselventilboh tion 61 is now much larger than in the first switching position of the throttle piston 66 , so that at 90 through the pressure compensator certain pressure drop between the inlet chamber 65 and the consumer chamber 28 of the directional control valve, the quantity of pressure medium flowing to the hydraulic cylinder 25 per unit of time is substantially smaller than in the first switching position of the throttle piston. The piston rod of the hydraulic cylinder is now extended at a slow speed.

The embodiment according to FIGS. 3 and 4 differs only in that from the embodiment according to FIGS . 1 and 2 in that the pilot valve 93 is now not installed in the end plate 17 , but on the narrow side 80 opposite the consumer connections 30 and 31 of the valve housing 20 is attached. This has the advantage that the directional valve disk 16 does not have to be directly adjacent to the end disk 17 , that rather between the directional valve disk 16 and the end disk 17 there are further directional valve disks which, for. B. are designed in the manner of the directional valve disc 15 , can be located without having to drill a channel 96 through these discs. In the embodiment according to FIG. 4, the channel 96 now leads from the pressure chamber 95 to the narrow side 80 of the valve housing 20 . A channel 98 leads from the inlet channel 12 and a channel 99 from the outlet chamber 33 laterally past the throttle valve bore 61 to the narrow side 80 of the valve housing. On the narrow side 80 , the channels 96 , 98 and 99 meet internal channels of the pilot valve 93 .

Claims (12)

1. hydraulic control arrangement, in particular for a vehicle for transporting skip,
with a directional control valve ( 8 ), which has an axially adjustable directional control piston ( 22 ) in a directional control valve bore ( 21 ), which is formed in a valve housing ( 20 ), with which the pressure medium paths between an inlet chamber ( 27 ), the pressure medium flows from a hydraulic pump ( 10 ), an outlet chamber ( 32 , 33 ), via which Druckmit tel flows to a tank ( 11 ), and a consumer chamber ( 28 , 29 ) which flows in or out from a hydraulic consumer ( 25 ) is controllable,
With a throttle valve ( 9 ), which has a throttle piston ( 66 ) axially displaceable in a throttle valve bore ( 61 ) of the valve housing ( 20 ), via which a connection with different throttle resistances between an input channel ( 65 ), the pressure medium from the hydraulic pump ( 10 ) flows, and an output channel ( 64 ) of the throttle valve bore ( 61 ), which is connected to the inlet chamber ( 27 ) of the Wegeven valve bore ( 61 ), can be produced and which is in the sense of a displacement in one direction from to a load sensing controller ( 90 ) load pressure of the hydraulic consumer ( 25 ) can be acted upon, characterized in that the throttle piston ( 66 ) can be shifted at will against the load pressure from a first position into a second position in which the throttle resistance of the connection between the input channel ( 65 ) and the output channel ( 64 ) is different from the throttle resistance of this connection in the first position t. 2. Hydraulic control arrangement according to claim 1, characterized in that adjacent to the throttle piston ( 66 ) next to the loadable control chamber ( 74 ) is adjacent to a second control room ( 95 ), depending on the position of an arbitrarily operable pilot valve ( 93 ) in the sense a displacement of the throttle piston ( 66 ) against the load pressure with a control pressure or is relieved of pressure. 3. Hydraulic control arrangement according to claim 2, characterized in that the second control chamber ( 95 ) can be acted upon by pump pressure. 4. Hydraulic control arrangement according to claim 3, characterized in that the second control chamber ( 95 ) in one position of the pilot valve ( 93 ) with a through the Ventilgehäu se ( 20 ) leading pump channel ( 12 ) and in the other position of the pilot valve ( 93 ) is connected to a tank channel ( 18 ) leading through the valve housing ( 20 ). 5. Hydraulic control arrangement according to claim 4, characterized in that the pilot valve ( 93 ) sits on a narrow side ( 80 ) of the valve housing ( 20 ). 6. Hydraulic control arrangement according to one of the preceding claims, characterized in that the throttle piston ( 66 ) can be acted upon by the load pressure in the direction of a position with a small throttle resistance between the input channel ( 65 ) and the output channel ( 64 ) of the throttle valve bore ( 61 ). 7. Hydraulic control arrangement according to claim 6, characterized in that the pilot valve ( 93 ) under the action egg ner spring ( 94 ) assumes the position in which the second control chamber ( 95 ) on the throttle piston ( 66 ) is relieved of pressure. 8. Hydraulic control arrangement according to claim 7, characterized in that the throttle piston ( 66 ) in the same effective direction as the load pressure from a spring ( 77 ) can be beat. 9. Hydraulic control arrangement according to one of the preceding claims, characterized in that in a position of the throttle piston ( 66 ) there is a flow path with high hydraulic resistance from the input channel ( 65 ) to the output channel ( 64 ) of the throttle valve bore ( 61 ) and in that second position of the throttle piston ( 66 ) additionally a flow path with a small hydraulic resistance is opened. 10. Hydraulic control arrangement according to one of the preceding claims, characterized in that the throttle piston ( 66 ) is a hollow piston with a cavity ( 67 ) through which, in a position which the throttle piston ( 66 ) seeks to assume under the effect of the load pressure, a flow path from the input channel ( 65 ) to the output channel ( 64 ) of the throttle valve bore ( 61 ), and that in the cavity the closing member ( 75 ) of a load holding valve ( 76 ) is arranged, which can be acted upon in the closing direction by the load pressure. 11. Hydraulic control arrangement according to claim 10, characterized in that the closing member ( 75 ) of the load holding valve ( 76 ) in the closing direction is acted upon by a spring ( 77 ) and can be pressed against the throttle piston ( 66 ) and that this Fe ( 77 ) supports an abutment ( 68 ) fixed to the housing. 12. Hydraulic control arrangement according to one of the preceding claims, characterized in that the directional control piston ( 22 ) has control grooves ( 36 ) for connecting the inlet chamber ( 27 ) to the consumer chamber ( 28 , 29 ) and in that the stroke of the way control piston ( 22 ) is provided by a adjustable stroke limiter ( 35 ) is adjustable.