EP1913259A1

EP1913259A1 - Control valve unit with alternating stops

Info

Publication number: EP1913259A1
Application number: EP06776614A
Authority: EP
Inventors: Grit Geissler; Horst Stegmaier
Original assignee: Brueninghaus Hydromatik GmbH
Current assignee: Brueninghaus Hydromatik GmbH
Priority date: 2005-08-09
Filing date: 2006-08-04
Publication date: 2008-04-23
Also published as: CN101151464B; CN101151464A; WO2007017197A1; DE102005037619B4; US20090133761A1; KR20080031854A; JP2009505004A; DE102005037619A1

Abstract

The invention relates to a control valve unit (9) for an adjusting device of a hydrostatic piston engine. The control valve unit (9) comprises a valve housing (34), in which a valve element can bemoved in a longitudinal direction. The valve element can be adjusted from a neutral position into a first end position and an opposite second end position. Along with an increasing adjustment of the valve element, a first or second outlet connection (35a, 35b) is connected in an increasing manner to an inlet connection (12). The other respective outlet connection (35b, 35a) is connected simultaneously to a relief line (13). The valve element comprises a first valve piston (32a) and a second valve piston (32b), which act upon one another via an elastic element (27).

Description

Control valve unit with changeover stop

The invention relates to a control valve unit for an adjusting device of a hydrostatic piston engine.

To adjust the delivery volume of a hydrostatic piston engine, it is often necessary to set in an adjusting two acting in the opposite direction to an adjusting actuating pressures. From DE 195 40 654 Cl a control valve is known for this purpose, in which a valve piston is arranged as a valve element longitudinally displaceable in a valve housing. The valve piston can be acted upon by a force at its oppositely oriented end faces. By an axial movement of the valve piston in one direction, an input pressure port is connected to a first output. At the same time, a second outlet is connected to a tank connection. When moving in the opposite direction, the second output port is connected to the input port while the first output port is connected to the tank port. In this way, the two acting in the opposite direction and associated with each output terminal control pressure chambers can be set to a direction and height adjustable force difference. The resulting actuating movement of the actuating piston is mechanically coupled back as a return force via a return element on the valve piston. The adjusting movement is transmitted by the return element and deflects one of two legs. The two legs are connected to each other via a spring, wherein each non-deflected leg is supported on a driving pin of the valve piston. In this way, the adjusting movement is transmitted by tensioning the spring connecting the two legs to the valve piston so that the resulting force counteracts the deflection of the valve piston. The adjustment described has the disadvantage that a considerable mechanical effort is required. Due to the one-piece valve piston, it is also necessary that in the valve housing a very precisely executed bore for receiving the valve piston is introduced. In this case, the one-piece design of the valve piston is required in order to be able to apply a counterforce for the return element in an adjustment of the actuating piston in both directions. In addition, considerable accuracy requirements are to be placed on the axial position of the individual control edges, since in each case a coupled movement of the two control pressure associated with the control edges.

The invention has for its object to provide a control valve unit for a hydrostatic piston engine, which has a reliable function and is easy to manufacture.

The object is achieved by the control valve unit according to the invention with the features of claim 1.

According to claim 1, the control valve unit according to the invention on a valve housing with a longitudinally displaceably arranged therein valve element. The valve element is adjustable from a neutral position in both directions, whereby a first or a second output port is increasingly connectable to an input port. Simultaneously with the increasing connection of the first or the second output terminal to the input terminal, the respective other output terminal is increasingly connected to a tank volume. According to the invention, the valve element is constructed in the control valve unit from a first valve piston and a second valve piston, wherein the two valve pistons act on one another via an elastic element. This allows a coupled adjustment of the entire valve element without that a rigid connection of the positions of the respective control edges is required. In particular, it is possible to bring one of the valve piston in a position in which the output terminal is connected via a large flow-through surface with the tank connection. By the elastic element at the same time the other valve piston remains arbitrarily adjustable. Therefore, the elastic element allows the relative movement of the two valve piston to each other, while still maintaining a coupling of the two valve piston with each other.

Furthermore, it is possible by the elastic coupling of the first valve piston and the second valve piston to influence the control behavior by acting on the respective valve piston axial forces. For example, it is possible to exert an increasing force on the one valve piston. This force is transmitted to the second valve piston, which, for example, is also still subjected to an opposite axial force. While the first valve piston is already being adjusted, the axial force can gradually be reduced successively on the second valve piston. With such a controlled admission of the two valve piston, each with its own force can be z. B. hydraulically clamp an adjusting piston at any time in an advantageous manner. The elastic element is compressed for this purpose, so that the opening on a control edge of a valve piston can be effected independently of the opening at a control edge of the other valve piston.

In the dependent claims advantageous developments of the control valve unit according to the invention are carried out.

In particular, it is advantageous to provide a control acting on an end face of each valve piston hydraulic force, which is generated by the pressure acting on the respective output port pressure. It is also advantageous, the hydraulic force at a to attack on an extension of reduced diameter formed end face of the valve piston. This is particularly advantageous by a sleeve, in which engage the two extensions of the valve piston. The sleeve has a separate control pressure chamber for each extension, in which the pressure of the corresponding output port acts on the end face of the extension. It is particularly advantageous to arrange the sleeve longitudinally displaceable on the two extensions and thus to enable a relative movement between the extensions and the sleeve.

The supply of the pressure prevailing in each case at the outlet connection is preferably effected by means of pressure medium channels formed in the respective valve piston.

It is particularly preferred to design the two valve pistons in identical geometry and to arrange them in opposite directions in the valve housing.

A preferred embodiment of the control valve unit according to the invention is shown in the drawing and will be explained in more detail in the following description. Show it:

Figure 1 is a schematic representation of an adjusting device for a hydrostatic piston engine.

2 shows a first partial section through a control valve unit according to the invention;

FIG. 3 is an enlarged view of a detail of the hydrostatic piston machine of FIG. 2 with a fixed sleeve; FIG.

4 shows a second partial section through a control valve unit according to the invention; 5 shows a third partial section through a control valve unit according to the invention;

Fig. 6 shows a first embodiment of a valve piston of the invention

Control valve unit; and

Fig. 7 shows a second embodiment of a valve piston of the control valve unit according to the invention.

1 is a schematic representation of an adjusting device of a hydrostatic piston machine is shown for ease of understanding of the control valve unit according to the invention. The hydrostatic piston engine is designed in FIG. 1 as an adjustable hydraulic pump 1, which is connected via a drive shaft 2 with a drive motor, not shown. The hydraulic pump 1 is provided for delivery into a first working line 25 or a second working line 26. The control valve unit according to the invention can also be used in a piston engine designed as a hydraulic motor.

For adjusting the delivery volume of the hydraulic pump 1, an adjusting device 3 is provided. The adjusting device 3 comprises a double-acting cylinder 4, in which an actuating piston 5 is arranged. The control piston 5 divides the cylinder 4 into a first control pressure chamber 6 and a second control pressure chamber 7, wherein the control piston 5 in both control pressure chambers 6, 7 can be acted upon by a hydraulic force. Via a piston rod 8, the adjusting movement of the adjusting piston 5 is transmitted to an adjusting mechanism of the hydraulic pump 1.

For adjusting the actuating pressure acting in the first actuating pressure chamber 6 and the second actuating pressure chamber 7, a control valve unit 9 is provided. The Control valve unit 9 is connected via a first control pressure line 10 and a second control pressure line 11 to the first control pressure chamber 6 and the second control pressure chamber 7. By means of the control valve unit 9, the first actuating pressure line 10 and the second actuating pressure line 11 can each be connected to a feed pressure channel 12 or an expansion line 13.

In a first end position of a valve element of the control valve unit 9 is thus, for example, the first

Signaling line 10 is connected to the feed pressure channel 12, while the second actuating pressure line 11 is expanded via the expansion line 13 into the tank volume 14. The force for adjusting the control valve unit 9 in the direction of the first shown in FIG

End position is determined by a first proportional magnet

15 generated on the valve element of the

Control valve unit 9 exerts an axial force. In the

Actuation of the first actuating pressure chamber 6 with the feed pressure and a simultaneous relaxation of the second actuating pressure chamber 7, the actuating piston 5 in the

Fig. 1 is a movement to the right.

In order to bring about a movement in the opposite direction, a second proportional magnet 16, which is directed counter to the first proportional magnet 15, is subjected to an actuating signal. As a result of the increasing force by the second proportional solenoid 16, the valve element of the control valve unit 9 is adjusted in the direction of a second end position, so that increasingly the second actuating pressure line 11 is connected to the feed pressure channel 12 and the first actuating pressure line 10 with the expansion line 13. As a result, the pressure gradient between the first control pressure chamber 6 and the second control pressure chamber 7 is reversed, and the control piston 5 is in the opposite direction, in the illustrated embodiment to the left, deflected. The control signals for the proportional magnet 15, 16 are determined by an electronic control unit 17. For this purpose, the electronic control unit 17 is connected via a first control line 18 and a second control line 19 to the first proportional magnet 15 and the second proportional magnet 16. The input variables for the electronic control unit 17 are, for example, a travel lever preset, which is transmitted to the electronic control unit 17 via a signal input line 20. In addition, the position of the actuating piston 5 is detected to determine the adjusted swing angle of the hydraulic pump 1. For this purpose, a position sensor 22 is arranged on the piston rod 8 of the actuating piston 5, the signal is transmitted via a first signal line 21 to the electronic control unit 17. Furthermore, for example, a temperature sensor 24 may be provided on the hydraulic pump unit, which transmits a measured temperature in the form of an electrical signal via a second signal line 23 to the electronic control unit 17.

Instead of the proportional magnets 15, 16, other means for generating the actuating forces can be provided. For example, Hydraulic forces can act on end faces of the valve element, which are preferably determined by adjustable by a pilot valve actuating pressures.

In Fig. 1, the division of the control valve unit 9 according to the invention in a first pressure reducing valve 9a and a second pressure reducing valve 9b is shown. The pressure reducing valves each have an output port and an input port. In the illustrated embodiment, the common input connection corresponds to the feed pressure channel 12 and the first and second output connection of the first and second control pressure lines 10 and 11, respectively. The output connections of the pressure-reducing valves 9a, 9b are also referred to as the outlet side. Each pressure reducing valve 9a, 9b is infinitely adjustable between a first end position and a second end position. In the first end position, the input terminal is connected to the respective output terminal. By contrast, in the second end position, the respective output connection is connected to the common expansion line 13.

The two pressure reducing valves 9a and 9b are coupled together by a spring 27, so that between the valve piston of the pressure reducing valves 9a, 9b shear forces can be transmitted. Instead of the spring 27 may also be another elastic element for coupling the two pressure reducing valves 9a and 9b are used. In Fig. 1, a first end position of the control valve unit 9 is shown. In this first end position, the feed pressure duct 12 is connected to the first actuating pressure line 10 by the first pressure reducing valve 9a. For this purpose, as will be explained with reference to further Figures 2 to 5, a valve piston of the first pressure reducing valve 9a is acted upon by a force by the first proportional solenoid 15 and moved in the direction of the second pressure reducing valve 9b. As a result, the valve piston is adjusted in the direction of its first end position, in which it connects the feed pressure channel 12 with the first actuating pressure line 10. The pressure prevailing in the first actuating pressure line 10 is applied via a control pressure channel 10 'to a first measuring surface 29 a, where it acts on the valve piston opposite to the force of the proportional magnet 15.

The spring 27, which has a bearing surface on the valve piston as a spring plate, is displaced by the movement of the valve piston in the direction of the second pressure reducing valve 9b and acts on the local valve piston with a force. If the second pressure reducing valve 9b is already in its second end position shown in FIG. 1 in the case of a de-energized proportional magnet 16, then a further movement of the valve piston in the direction of this end position is present not possible. As a result of the movement of the valve piston of the first pressure-reducing valve 9a, the spring 27 is compressed.

Also at the second pressure reducing valve 9b an equilibrium position is assumed by the valve piston, which is due to the force of the spring 27, the opposing force of the second proportional solenoid 26 and a hydraulic force acting on a second measuring surface 29b of the second pressure reducing valve 9b adjusted. In order to produce the hydraulic force on the second measuring surface 29b of the second pressure reduction valve 9b of the pressure of the second setting pressure line 11 via a second control pressure channel II ¹ of the second measuring surface 29b is supplied. In the second end position of the second pressure reducing valve 9b, the second actuating pressure line 11 is connected to the expansion line 13 and thus relaxes the second actuating pressure chamber 7 into the tank volume 14.

2, a control valve unit 9 according to the invention is shown as a partial section. The control valve unit 9 is acted upon via a feed pressure channel 12 as a common input port, which is incorporated in the illustrated embodiment as a groove in a side wall of the control valve unit 9, with a feed pressure. The first pressure-reducing valve 9a or the second pressure-reducing valve 9b is supplied with the feed pressure via a first feed pressure passage section 12a and a second feed pressure passage section 12b, respectively. The construction and the function of the two pressure reducing valves 9a, 9b will be explained below with reference to the first pressure reducing valve 9a shown on the left in FIG. The reference numerals of the elements of the first pressure reducing valve 9a are marked with the letter suffix "a". In order to avoid unnecessary repetitions, a separate explanation of the second pressure reducing valve 9b of the same design is dispensed with. The corresponding reference numerals of the second Pressure reducing valve 9b are each marked with the letter suffix "b".

Connected to the first feed pressure passage section 12a is a first annulus 31a formed around a reduced diameter portion of the first valve spool 32a. The first valve piston 32a is in a running as a bore 33 recess of the

Valve housing 34 of the control valve unit 9 is arranged. The second valve piston 32 b is arranged in the opposite direction in the bore 33.

The bore 33 has a radially expanded region, which forms a second annular space 35a around the first valve piston 32a. A further radially expanded region of the bore 33 forms a third annular space 36, which in the illustrated embodiment is designed to be common for both pressure reducing valves 9a, 9b and is connected to the expansion line 13 in a manner not shown.

In the axial direction, the first annular space 31a is bounded by a first portion 37a, which is formed on the first valve piston 32a. Spaced to the first portion 37a of the first valve piston 32a, a second portion 38a is formed on the first valve piston 32a. Between the sections 37a and 38a, a further, reduced in its radial extent region of the first valve piston 32a is formed. The distance between the mutually remote circumferential edges of the two sections 37a, 38a formed on control edges is less than the axial extent of the second annular space 35a. Depending on the axial position of the first valve piston 32a, the first portion 37a and the second portion 38a, respectively, sealingly cooperate with the bore 33. In the first end position of the first valve piston 32a "shown in FIG. 2, the first portion 37a sealingly cooperates with the bore 33, so that a connection between the first annular space 31a and the second annulus 35a is interrupted. In contrast, the second radial extension 38a is in the region of the second annular space 35a, so that there is a flow-through connection between the second annular space 35a and the third annular space 36.

The second annular space 35a is connected to the first control pressure line 10, not shown in FIG. In the illustrated first end position of the first pressure reducing valve 9a, therefore, the connection between the feed pressure channel 12 and the first control pressure line 10 is interrupted, whereas the pressure medium from the first control pressure chamber 6 via the first control pressure line 10, the first annular space 35a and the third annular space 36 in the expansion line 13 and can flow into the tank volume 14.

On its side facing the third annular space 36, the first valve piston 32a has a first extension 39a. The first extension 39a is preferably cylindrical in shape, wherein the free end may have a phase, and projects a little way into a sleeve 40. The sleeve 40 is pushed in the same way over a second extension 39b of the second valve piston 32b, wherein from the extension 39a and the sleeve 40 and the extension 39b and the sleeve 40, the inner volume of the sleeve 40 to a first control pressure chamber 42a and a second Regeldruckraum 42b is closed. In the sleeve 40, a partition wall 41 is arranged for this purpose.

At the end face of the first extension 39a, the first measuring surface 29a is formed, to which acts via a control pressure channel 10 ', which is only partially visible in FIG. 2, the pressure prevailing in the second annular space 35a. On the end face of the first extension 39a thus acts the drain-side pressure of the first Druckredzierventils 9a. An increase in pressure in the first actuating pressure chamber 6 thus causes a force which is opposite to that of the first valve piston 32 Proportional magnet 15 generated applied force. The drain-side pressure is thus regulated to a predetermined value by the force of the first proportional solenoid 15.

The first proportional magnet 15 is preferably screwed into the valve housing 34 via a first threaded connection 43a and acts via a plunger on a first end face 44a, which is formed on the end of the first valve piston 32a directed towards the outside of the valve housing 34. If an actuating signal is supplied to the first proportional magnet 15 via a signal line, not shown, the proportional magnet 15 generates on the end face 44a of the first valve piston 32a a positioning force which shifts the first valve piston 32a in FIG. 2 to the right. Thus, the first portion 37 a and the second portion 38 a are shifted to the right until the second portion 38 a sealingly cooperates with the bore 33 and so breaks the connection between the second annular space 35 a and the third annular space 36.

At the same time, the first section 37a is displaced into the region of the second annular space 35a, so that the corresponding control edge releases a through-flow connection between the first section 37a and the bore 33. The pressure prevailing in the first feed pressure channel section 12a thus increasingly also acts in the second annular space 35a, so that pressure medium flows into the first control pressure chamber 6. The rising pressure in the second annular space 35a is supplied via the first control pressure channel 10 'to the first control pressure chamber 42a in the displaceable sleeve 40 and acts there on the first measuring surface 29a. Due to the increasing pressure, a hydraulic force is generated which counteracts the actuating force of the first proportional magnet 15. The first valve piston 32a thus assumes an equilibrium position in which the hydraulic force at the first Measuring surface 29 a together with the force of the spring 27, the force of the proportional solenoid 15 compensated.

Due to the increasing pressure in the first control pressure chamber 42a, the sleeve 40 and the spring 27 are displaced to the right in FIG. A displacement of the sleeve 40 is possible because the axial extent of the sleeve 40 is smaller than the distance between the corresponding contact surfaces 45a, 45b on the first valve piston and the second valve piston 32a, 32b. The contact surfaces 45a, 45b are provided on a collar formed on the valve piston 32a, 32b. The length of the sleeve 40 is preferably dimensioned such that both valve pistons 32a and 32b can be brought into their respective first end position by a force of the proportional solenoids 15, 16, in which the respective feed pressure channel sections 12a, 12 with the second annular space 35a of the first pressure reducing valve 9a or are connected to the second annular space 35b of the second pressure reducing valve 9b. The displacement of the sleeve 40 and the spring 27 takes place until a corresponding counterforce is applied by the second valve piston 32b.

In a deflection of the first valve piston 32a by a force of the first proportional solenoid 15, the pushed over the sleeve 40 spring 27, which is freely movable on the sleeve 40, acted upon with a direction of the second valve piston 32b force. In the embodiment shown in FIG. 2, the spring 27 is supported on the second portion 38a of the first valve piston 32a and the second portion 38b of the second valve piston 32b. A movement of the first valve piston 32a in the direction of the second valve piston 32b thus produces on the second valve piston 32b an axial force which acts on the second valve piston 32b in the direction of the second proportional magnet 16. If the axial force generated by the force of the spring 27 together with the hydraulic force on the end face of the extension 39b on the second valve piston 32b the Setting force of the second proportional solenoid 16 exceeds the second valve piston 32 b is brought into its second end position shown in FIG. 2 and held there ^■ .

In order to enable a delayed release of the second actuating pressure chamber 7, however, it may also be provided that initially by the second proportional solenoid 16 a force is generated on the second valve piston 32b, so that a connection between the third annular space 36 and the second annular space 35b of second pressure reducing valve 9b is still interrupted, while on the first pressure reducing valve 9a already a pressure in the first actuating pressure chamber 6 is established. This has the advantage that the adjusting piston 5 is hydraulically clamped at any time of an adjustment.

If a sufficiently high pressure in the control pressure chamber 6 is generated, the signal for the second proportional solenoid 16 is reduced, so that by the force of the spring 27 and the hydraulic differential force on the sleeve 40 of the second valve piston 32 b in the direction of the in FIG .. 2 shifted shown end position and thus the second actuating pressure chamber 7 is increasingly relaxed.

The above statements apply analogously to a deflection of the control valve unit 9 in the opposite direction.

In FIG. 2, the control valve unit 9 is shown in its rest position, in which both proportional magnets 15, 16 receive a vanishing control signal. The length of the spring 27 is dimensioned such that it acts on the first valve piston 32a and the second valve piston 32b with non-energized proportional magnets 15, 16, so that the two valve pistons 32a, 32b in the second end position shown in FIG the pressure reducing valves 9a, 9b return. This ensures that at any time the Valve piston 32a, 32b are in a defined position. In particular, it is not necessary to have to generate a pressure in the control pressure chambers 42a, 42b in order to hold the valve pistons 32a, 32b in contact with the plungers of the proportional magnets 15, 16.

In the illustrated embodiment of Fig. 2, the sleeve 40 is freely movable on the extensions 39a, 39b arranged. It is also possible to arrange the sleeve 40 fixed in the third annular space 36, as shown in FIG. 3. A sleeve 40, which is fixedly arranged in the third annular space 36, has the advantage that, in the event of a pressure increase in one of the control pressure chambers 42a, 42b, the increasing volume in the control pressure chamber 42a or 42b does not first have to be filled up. This leads to a faster response of the pressure reducing valves 9a, 9b. The fixation of the sleeve 40 can be done for example by a clamping screw 65. The spring 27 can be chosen with a pitch that still allows its axial displacement.

The respective first annular space 31a, 31b of the first pressure-reducing valve 9a and the second pressure-reducing valve 9b is delimited in the direction of the proportional magnet 15 or the proportional magnet 16 by a region sealingly cooperating with the bore 33. Along this seal, a low leakage current forms, since the first annular spaces 31a, 31b are each subjected to the feed pressure. For discharging the leakage fluid in each case a leakage oil passage portion 46a, 46b is provided, which opens into a drain hole 46. The leakage oil bore 46 is connected to the expansion line 13, so that the resulting leakage fluid can flow away in the direction of the tank volume 14. The leakage oil bore 46 is introduced from one side into the valve housing 34 as a blind bore and is closed by a plug 47. As has already been explained, the feed pressure channel 12 is introduced in the illustrated embodiment of the control valve unit 9 as a groove in a side wall of the valve housing 34. The groove is closed by contact with a housing portion of an adjusting device, not shown. In order to hold the valve housing 34 in a defined position relative to the housing portion of the adjusting device 34, dowels 48a, 48b are provided in the valve housing. For fixing threads 49a, 49b are arranged, with which the control valve unit 9 is screwed to the adjusting device 3.

FIG. 4 shows a second view of the control valve unit 9 according to the invention. It can be seen that protrudes from a contact surface 66 of the valve housing 34, a return lever 50, at its end facing away from the valve housing 34 a driving head 51 is formed. With the driving head 51, the return lever 50 engages in the adjusting piston 5 of the adjusting device 3. The return lever 50 is fixedly connected to a shaft 52, wherein the shaft 52 is rotatably mounted in the valve housing 34. During an actuating movement of the actuating piston 5, the linear actuating movement of the actuating piston 5 is converted into a rotational movement of the shaft 52 via the return lever 50. The respective angular position of the shaft 52, which corresponds to a specific set delivery volume, can be detected electronically, for example, and incorporated in the determination of the actuating signals for the proportional magnets 15, 16.

FIG. 5 shows the control valve unit 9 according to the invention in a section through the valve housing 34. It can be seen that the second annular spaces 35a, 35b are connected via bores through the valve housing 34 to the first actuating pressure line 10 and the second actuating pressure line 11, respectively. The outwardly open holes in the housing 34 are closed by plugs 54, 55. Furthermore, a passage 53 can be seen, which serves to lead out the return lever 50 from the valve housing 34. The oval passage 53 extends in FIG. 5 perpendicular to the plane of the drawing and is connected to the third annular space 36, thus the third annular space 36 can be connected to the tank volume 14 via the passage 53.

6 is an enlarged view of a first embodiment of a valve piston 32a, 32b shown. Since the valve piston 32a, 32b are made identical, is subsequently dispensed with a use of the letter additions. At a first end 56 of the valve piston 32, the abutment surface 44 is formed. In the region of the first end 56, the diameter of the valve piston 32 corresponds to the bore 33 of the valve housing 34, so that a sealing effect is achieved. Likewise, the diameter of the first portion 37 and of the second portion 38 corresponds to the diameter of the bore 33. Between the first end 56 and the first portion 37 a reduced in its radial extent portion 57 is formed, so that a circumferential groove around the valve piston 32nd arises, which together with the bore 33 forms the respective first annular space 31a, 31b.

Likewise, a second reduced in its radial extent region between the first portion 37 and the second portion 38 is formed. On the side remote from the first end 56, the extension 39 is formed following the second section 38. The extension 39 is further reduced in diameter relative to the reduced region 57, and its end face is designed as a measuring surface 42 which, when acted upon by the discharge-side pressure, generates a force opposing the force of the magnet which can be generated in size in the region of the magnet Power lies. By means of the diameter of the extension 39 can thus be on the valve piston 32nd adjust acting hydraulic force to the proportional magnets used. At the opposite edges of the first portion 37 and the second portion 38, a first control edge 58 and a second control edge 59 are formed. At the first and the second control edge 58, 59, the displaceable connections between the first annular spaces 31a, 31b and the second annular spaces 35a, 35b and the second annular spaces 35a, 35b and the third annular space 36 are displaced by displacement of the valve piston 32 in the bore 33 generated.

In the sectional view of the valve piston 32, the actuating pressure channel 10 'or 11' can be seen. The actuating pressure channel 10 'or 11' consists of a transverse bore 62, which is arranged in the region between the first portion 37 and the second portion 38. The transverse bore 62 is thus always in communication with the second annular space 35 and performs the drain-side pressure of the reducing valve 9a and 9b. In order to supply the guided in the transverse bore 62 pressure of the measuring surface 42, a longitudinal bore 63 is formed in the axial direction in the extension 39, which opens in the illustrated first embodiment of a valve piston 32 in FIG. 6 via a throttle point 64 in the transverse bore 62. Through the restrictor 64, which is designed as a reduced diameter bore section, the inclination of the Druckredzierventils 9a, 9b is reduced to vibrate. In the throttle point 64, this is done at the pressure equalization or the Volumenaugleich the control pressure chamber 42, a damping.

FIG. 7 shows a second exemplary embodiment of a valve piston 32, in which the throttle point 64 is dispensed with. In addition, on the valve piston 32 of FIG. 7, the contact surface 45 can be seen, on which the sleeve 40 is supported. The contact surface 45 is formed by a step in the transition from the extension 39 to the second portion 38. The first end 56, the first section 37 and the second Section 38 are preferably produced by a machining operation, in which by turning the reduced diameter in the region 57 and the region between the sections 37 and 38 circumferential grooves are introduced. The area between the sections 37 and 38 and the radially reduced area 57 and the collar 60, on which the contact surface 45 is formed, preferably have an identical diameter.

The invention is not limited to the illustrated embodiments. Rather, the individual features of the embodiments can be combined with each other in any desired manner.

Claims

claims

A control valve unit having a valve element (34) arranged longitudinally displaceable valve element which is adjustable from a neutral position towards a first end position and an opposite second end position, wherein with increasing adjustment, a first output terminal (10, 35 a) or a second output terminal ( 11, 35b) is increasingly connectable to an input port (12) and the other of the two output ports (11, 35b; 10, 35a) is increasingly connectable to a flash line (12), characterized in that the valve element comprises a first valve piston (32a ) and a second valve piston (32b) which act on one another via an elastic element (27).

Second control valve unit according to claim 1, characterized in that the first valve piston (32 a) by a first actuating force in the direction of the second valve piston (32 b) and the second valve piston (32 b) by a second actuating force in the direction of the first valve piston (32 a) can be acted upon.

3. Control valve unit according to claim 2, characterized in that the elastic element (27) on the first and the second valve piston (32 a, 32 b) exerts one of the first and the second actuating force opposing force.

4. control valve unit according to one of claims 1 to 3, characterized in that the first valve piston (32 a) and the second valve piston (32 b) each have an end face (42 a, 42 b) which with the pressure of the first output terminal (10, 35 a) or the pressure of the second output terminal (11, 35b) is acted upon.

5. Control valve unit according to claim 4, characterized in that the end face (42a, 42b) in each case on an extension (39a, 39b) of the first and the second valve piston (32a, 32b) is formed and the extensions (39a, 39b) in a first control pressure chamber (42a) and a second control pressure chamber (42b) of a common sleeve (40) engage.

6. Control valve unit according to claim 5, characterized in that the sleeve (40) is arranged axially displaceably on the extensions (39 a, 39 b).

7. Control valve unit according to claim 5 or 6, characterized in that the extensions (39a, 39b) of the first and the second valve piston (32a, 32b) protrude into a with the expansion line (13) connected to the annular space (36), in which the sleeve (40) is arranged substantially.

8. Control valve unit according to one of claims 5 to 7, characterized in that for supplying the pressure of the first

Output terminal (10, 35a) and the second

Output terminal (11, 35b) to the first

Control pressure chamber (42 a) and the second control pressure chamber

(42b) in the valve piston (32a, 32b) in each case a control pressure channel (10 ', 11') is formed.

9. Control valve unit according to one of claims 1 to 8, characterized in that the first valve piston (32a) and the second valve piston (32b) with the valve housing (34) form a first pressure reducing valve (9a) and a second pressure reducing valve (9b).

10. Control valve unit according to one of claims 1 to 9, characterized in that the first valve piston (32a) and the second valve piston (32b) are made the same and in a common recess (33) of the valve housing (34) are arranged opposite to each other.

11. Control valve unit according to one of claims 1 to 10, characterized in that the first and the second valve piston (32a, 32b) can be acted upon by a respective force generated by a respective proportional solenoid (15, 16).

12. Control valve unit according to one of claims 1 to 10, characterized in that the first valve piston (32a) and the second valve piston (32b) are each acted upon by a hydraulic force.