Valve section and hydraulic valve assembly

Abstract

The present invention relates to a valve section 10 with a pressure channel 12, a load pressure signaling channel 26, an association load pressure channel 32, a spool valve 16, a pressure compensator 24, a first and a second hydraulic connection A, B, and a first line 20.1, 20.2 connecting the pressure channel 12 to the spool valve 16. The pressure compensator 24 is arranged in the first line 20.1, 20.2. A first pressure signal P1, tapped via a first pilot line 23.1 between the pressure compensator 24 and the spool valve 18, is applied to the closing side of the pressure compensator 24. A second pressure signal P2 is applied to the opening side of the pressure compensator 24 via a second pilot line 23.2 connected to the load pressure signaling channel 26. A third pressure signal P3, tapped from the assembly load pressure channel 32 via a third pilot line 23.3, is applied to the pressure compensator 24 on the control side. A fourth pressure signal P3 is applied via a fourth pilot line 23.4. The pressure signal P5 tapped between the pressure channel 12 and the pressure compensator 24 is applied to the upstream side of the pressure compensator 24. A fifth pilot line 23.5 branches off between the pressure compensator 24 and the spool valve 16, with the fifth pilot line 23.5 being connected to the second pilot line 23.2. A first hydraulic resistor 34 is arranged in the fifth pilot line 23.5, and a second hydraulic resistor 36 is arranged in the second pilot line 23.2. The invention further relates to a hydraulic valve assembly 100 having such a valve section 10.

Description

[0001] The present invention relates to a valve section for a hydraulic valve assembly and a hydraulic valve assembly with such a valve section.

[0002] Such hydraulic valve assemblies are known from the prior art, for example, the applicant's product "PSL." These hydraulic valve assemblies typically comprise a connection section and an end plate, as well as a plurality of valve sections arranged between the connection section and the end plate. Each valve section typically has at least two hydraulic connections for connecting one or more hydraulic consumers.

[0003] The valve sections can be pressurized via a pressure channel by connecting the connection section to each valve section. The valve sections usually each have a spool valve, an electro-hydraulic pilot control for actuating the spool valve, and an upstream pressure compensator. A common pilot pressure signal can be applied via the connection section to the respective electro-hydraulic pilot control of each valve section in order to move the respective spool from the neutral position and thus control the connected hydraulic consumers (e.g. cylinders or hydraulic motors). Depending on the switching position of the spool valve, the pressure channel is connected to one of the two hydraulic connections via a first line, with the other hydraulic connection being connected to a return channel via a second line.

[0004] An upstream pressure compensator is a pressure compensator located upstream of the spool in the first line, as seen in the direction of flow from the connecting section to the spool. Such hydraulic valve banks are thus designed as load-sensing systems and feature a load pressure collection channel for reporting the highest load pressure present in the system. Each valve section has a load pressure reporting channel connected to the load pressure collection channel to report the load pressure currently present at the valve section.

[0005] In other words, the highest load pressure in the system is reported to all pressure compensators by all valve sections to regulate the overall flow requirement of the hydraulic system. The valve section with the highest load pressure specifies the pump pressure to be set. The respective pressure compensator compares the load pressure present in the corresponding valve section with the pump pressure. The pressure difference between the load pressure of the valve section and the pump pressure is normally adjusted via a spring element in the pressure compensator. Because the pressure difference remains constant, the volume flow depends solely on the downstream flow area of ​​the spool valve.

[0006] Such hydraulic valve groups or hydraulic systems with upstream pressure compensators are used in a wide variety of mobile hydraulic applications due to their simple and proven flow control, for example in forestry cranes, harvesters, feller bunchers or concrete pumps.

[0007] A disadvantage of these hydraulic systems with upstream pressure compensators, however, is their behavior in the event of an undersupply, i.e., when the maximum flow rate or volume flow of the pump is less than the sum of the quantities required by the connected hydraulic consumers. In such an undersupply, the pressure compensators of the valve sections with the highest load pressures may no longer regulate and open fully. In the event of an undersupply, the valve sections are supplied depending on their load pressure, i.e., those valve sections with the lowest load pressure first. This leads to the hydraulic consumers with high load pressures experiencing a significant reduction in speed or even coming to a standstill.

[0008] This control behavior in the event of undersupply can be prevented by downstream pressure compensators, which is also referred to as "flow sharing". In such flow-sharing hydraulic systems, the pressure compensators are not arranged between the pump or connection section and the spool, but between the spool and the hydraulic consumer, as known, for example, from DE 102 53 131 B4 or DE 10 2016 117 207 A1. If an undersupply occurs in such a hydraulic system with downstream pressure compensators, the flow rate is reduced proportionately across all valve sections to be supplied. Individual hydraulic consumers are therefore not undersupplied and there is no downtime. The disadvantage of these hydraulic systems with downstream pressure compensators, however, is higher energy consumption and increased heating of the hydraulic fluid.Especially in view of the rather rare case of undersupply, the use of hydraulic systems with downstream pressure compensators is significantly less attractive.

[0009] Alternatively, an upstream pressure compensator can be used, which not only reports the load pressure of the individual valve section, but also sends a load pressure signal to the pressure compensator, which depends on the highest load pressure in the system. For this purpose, the corresponding valve section then has a combined load pressure channel from which the corresponding load pressure signal is tapped. The highest load pressure present in the entire system is usually reported via the connecting section into the combined load pressure channel. Such a hydraulic system is known, for example, from US Pat. No. 5,937,645 A.A first pressure signal tapped between the pressure compensator and the slide valve is applied to the pressure compensator on the closing side via a first pilot line, a second pressure signal tapped from the load pressure signaling channel is applied to the opening side of the pressure compensator via a second pilot line, a third pressure signal tapped from the assembly load pressure channel via a third pilot line is applied to the closing side of the pressure compensator, and a fourth pressure signal tapped between the pressure channel and the pressure compensator is applied to the opening side of the pressure compensator via a fourth pilot line. With such pressure compensators, the spring element required to adjust the pressure difference can also be omitted, which has an extremely favorable effect on the space required for the pressure compensator. In the sense of the present disclosure, “opening side” is understood to mean the direction of a pressure signal or a force that generates an opening movement of the pressure compensator.Therefore, “control side” refers to the direction of a pressure signal or a force that generates a closing movement of the pressure compensator.

[0010] For individual valve sections, it may be necessary to enable relatively high volume flows of more than 120 l / min and even more than 130 l / min. To achieve this, the upstream pressure compensators must also be able to offer sufficiently large flow areas while remaining largely fully open. One option is to mechanically "preload" the pressure compensator, but this is usually not possible due to space constraints. Alternatively, the control piston of the pressure compensator can be made larger, which in turn is problematic due to space constraints, as the desired flow areas must be maintained to avoid generating unacceptably high back pressures. Finally, the use of one or more copying valves to increase the reported signals would also be possible. If these valves are arranged in the connection section, the signals are increased globally for the entire hydraulic valve bank.However, this is usually undesirable, so the valves must be located in the respective section. This increases costs and can lead to unwanted vibrations in the hydraulic system.

[0011] It is therefore the object of the present invention to provide a simple and space-saving valve section with an upstream pressure compensator, with which high volume flows of more than 120 l / min are possible and at the same time the risk of undersupply is reduced.

[0012] The problem is solved with a valve section according to claim 1. Advantageous further developments are described in the dependent claims.

[0013] The object is further achieved with a hydraulic valve assembly according to claim 13. The hydraulic valve assembly according to the invention comprises at least one valve section according to the invention. Preferably, the hydraulic valve assembly comprises a plurality of valve sections according to the invention. In addition to the at least one valve section according to the invention, the hydraulic valve assembly can also comprise "conventional" valve sections.

[0014] The valve section according to the invention is distinguished from the systems known from the prior art in particular by the fact that a fifth pilot line branches off between the pressure compensator and the slide valve, wherein the fifth pilot line is connected to the second pilot line. According to the invention, a first hydraulic resistance is arranged in the fifth pilot line and a second hydraulic resistance is arranged in the second pilot line.

[0015] Thus, according to the invention, a series connection of the first hydraulic resistance and the second hydraulic resistance is achieved, which causes an upstream inoculation of the pressure difference across the pressure compensator. As a result, an additional force component, dependent on the first and second hydraulic resistance, acts on the pressure compensator, increasing the overall pressure difference, which in turn increases the volume flow through the pressure compensator. The degree of inoculation can be precisely adjusted using the first hydraulic resistance and the second hydraulic resistance.

[0016] This can be explained using an example. Downstream of the pressure compensator, for example, 106 bar can be present in the first line. Downstream of the spool valve, 100 bar can be present at the first or second hydraulic connection, for example, due to the throttle point formed on the spool valve. This 100 bar is reported via the load pressure signal channel. In the fifth pilot line, upstream of the first hydraulic resistance, 106 bar is also present. Upstream of the second hydraulic resistance on the load pressure signal channel side, 100 bar is present. Because the first hydraulic resistance and the second hydraulic resistance are connected in series, with an appropriate selection of the diameters of the hydraulic resistances, the pressure in the second pilot line can be set, for example, to 103 bar.Therefore, this pressure is applied to the pressure compensator on the upstream side and not the pressure of the load pressure signaling channel, which is 3 bar lower, as is the case with the state of the art.

[0017] It is advantageous if the first hydraulic resistance is a first nozzle and / or if the second hydraulic resistance is a second nozzle, with the first nozzle preferably being an adjustable nozzle. The degree of inoculation can be precisely selected via this nozzle chain. Furthermore, the adjustability of the first nozzles allows for a certain degree of customization. The adjustability of the first nozzle can be achieved, for example, by using a threaded throttle or by replacing the nozzle elements.

[0018] Advantageously, the first pressure signal is dampened by a third hydraulic resistance, preferably a third nozzle. The third hydraulic resistance thus dampens any vibrations that may occur at the pressure compensator.

[0019] It is advantageous if the pressure compensator has a pressure compensator housing with a piston bore and a control piston guided axially movably in the piston bore. Preferably, the pressure compensator further comprises a first auxiliary piston and a second auxiliary piston, wherein the control piston is guided on the first auxiliary piston and the second auxiliary piston is preferably positively connected to the control piston. It is conceivable for the pressure compensator housing to be part of a housing of the valve section. The pressure compensator housing can be an integral component of the housing of the valve section or a separate part of the housing of the valve section. It is also conceivable for the second auxiliary piston to be connected to the control piston in some other way or to be formed integrally with the control piston.

[0020] The control piston expediently has a first guide surface guided in the piston bore, a second guide surface guided in the piston bore, and an at least partially circumferential recess located between the first guide surface and the second guide surface. A control edge is formed at the transition between the first guide surface and the recess. The control edge defines a flow area of ​​the first line depending on the axial position of the control piston in the piston bore. Thus, depending on the position of the control piston, the flow area of ​​the first line is enlarged (and thus permits more volume flow) or reduced (and thus permits less volume flow). Due to the second pressure signal, the control piston is already "preloaded" in the opening direction. A further (second) control edge can be formed at the transition between the second guide surface and the recess.

[0021] It is advantageous if the valve section has a plug, whereby the second auxiliary piston is guided axially in the plug and defines a first chamber with the plug, whereby the third pressure signal is present in the first chamber. The third pressure signal therefore acts on the second auxiliary piston and thus also on the control piston positively connected to it. The use of a plug also has the advantage over direct guidance in the pressure compensator housing that it enables simplified production. The plug can also be made from a different material than the pressure compensator housing, which, for example, is more wear-resistant. This increases the service life of the pressure compensator with only a slight increase in material costs, if any.

[0022] The control piston preferably has a first guide section, and the plug preferably has a second guide section, wherein the first guide section and the second guide section engage with one another. The first guide section can, for example, be pot-shaped, so that the second guide section—depending on the position of the control piston relative to the plug—is arranged at least partially radially within the first guide section. Furthermore, the plug can have a stop against which the first guide section strikes when the control piston is at its maximum opening, thus defining an end position of the control piston.

[0023] Preferably, the first guide section and the second guide section define a second chamber, wherein the control piston has at least one first connecting line connecting the second chamber to the first guide surface, wherein the first pressure signal is present in the second chamber. The first pressure signal is tapped from the first line downstream of the pressure compensator and transmitted to the second chamber via the first connecting line, preferably via the third hydraulic resistance. Of course, the control piston can also have a plurality of first lines, which are preferably evenly distributed.

[0024] The control piston, the first auxiliary piston and the pressure compensator housing expediently define a third chamber, with the second pressure signal being present in the third chamber. The first hydraulic resistance and the second hydraulic resistance are therefore connected in series, so that a (second) pressure signal acts in the third chamber which is smaller than the first pressure signal present in the second chamber. The pressure signal in the third chamber therefore only acts on the control piston. The first auxiliary piston is held in its position due to the higher pressure in the third chamber. It is also conceivable that the third chamber is additionally formed by an element adjacent to the valve section in the axial direction with respect to the control piston, for example a connection section, an end plate or another valve section.It is also conceivable that the first auxiliary piston is fixed to the adjacent element or is formed integrally with it.

[0025] Preferably, the first auxiliary piston and the control piston define a fourth chamber, wherein the control piston has at least one second connecting line extending through the control piston from the recess into the fourth chamber, wherein the fourth pressure signal is present in the fourth chamber. It is also conceivable, of course, for the control piston to have a plurality of preferably uniformly arranged second connecting lines. The fourth pressure signal is tapped from the first line upstream of the pressure compensator and transmitted to the fourth chamber via the at least one second connecting line.

[0026] Preferably, the control piston is movable in a first axial direction, and the slide valve preferably has a slide piston movable in a second axial direction, wherein the first axial direction and the second axial direction are not parallel. In a lateral projection, the first axial direction and the second axial direction are preferably perpendicular to each other. In other words, the control piston is arranged transversely to the slide piston in the valve section, thus achieving a particularly compact valve section.

[0027] It is advantageous if the control piston has an eccentric bore with a collar that only partially surrounds it. The second auxiliary piston preferably has a circumferential receptacle at its end facing the control piston, wherein the partially circumferential collar is at least partially arranged in the receptacle when the second auxiliary piston is positively connected to the control piston. To assemble the pressure compensator, the second auxiliary piston is inserted eccentrically into the first guide section and moved axially along the eccentric bore. As soon as the end position is reached, the second auxiliary piston is moved radially so that the partially circumferential collar engages in the receptacle. Axial movement of the second auxiliary piston relative to the control piston is then no longer possible due to this positive connection.

[0028] The hydraulic valve bank preferably has a connecting section connected to the valve section. The load pressure signaling channel is preferably connected to the load pressure collection channel via a shuttle valve, and the load pressure collection channel is preferably connected to the bank load pressure channel via a load pressure connection line of the connecting section. It is further advantageous if a fourth hydraulic resistance is arranged in the load pressure connection line. The fourth hydraulic resistance can be a fourth nozzle. Thus, the third pressure signal can be globally influenced to achieve the desired control behavior of the pressure compensators.

[0029] The invention is explained in more detail below using exemplary embodiments shown in the figures. The figures schematically show: Fig. 1 a hydraulic circuit diagram of a hydraulic valve assembly with two valve sections according to the invention, Fig. 2 shows a first section through a pressure compensator of a valve section according to the invention; and Fig. 3 a second section through a pressure compensator of a valve section according to the invention.

[0030] Fig. Figure 1 shows a hydraulic circuit diagram of a hydraulic valve bank 100 according to the invention. In this exemplary embodiment, the hydraulic valve bank 100 has two identically constructed valve sections 10, a connection section 102, and an end plate 104. Of course, the hydraulic valve bank 100 can also have only one valve section 10 or more than two valve sections 10. Furthermore, the valve sections do not have to be identically constructed, but can also differ in construction depending on requirements. Fig. For reasons of clarity, reference numerals are shown only in the valve section 10 located directly next to the connection section 102. Furthermore, only one valve section 10 is described below, with the design also correspondingly valid for the other valve section 10.

[0031] In the Fig. 1, the valve sections 10 are supplied with pressure via the connection section 102 by connecting a pump (not shown) to the pump connection 106 in a known manner. Returning hydraulic fluid is discharged into a tank (not shown) via the tank connection 108 in a likewise known manner. In this embodiment, the connection section 102 has a supply regulator 110 for use with a variable displacement pump. Of course, a connection section 102 with a flow control valve with a circulation circuit for use with a fixed displacement pump can also be used. Furthermore, the connection section 102 has a pilot pressure valve 112 in the form of a pressure control valve in order to provide a pilot pressure for the valve sections 10 in a known manner.

[0032] The valve section 10 has a pressure channel 12 and a return channel 14. The pressure channel 12 is pressurized in a known manner via the inlet regulator 110, and the return channel 14 is connected to the tank connection 108 via the connection section 102 in a known manner.

[0033] Furthermore, the valve section 10 has a slide valve 16 with a slide piston 18. The slide valve 16 is connected to the pressure channel 14 via a first line 20.1, 20.2 and to the return channel 14 via a second line 22. The slide valve 16 is designed in a known manner as a proportional and pilot-controlled slide valve 16 and can be Fig. 1 shown neutral position into a first switching position a and a second switching position b. In the first switching position a, a first hydraulic connection A of the valve section 10 is connected to the first line 20.1, 20.2 and a second hydraulic connection B of the valve section 10 is connected to the second line 22. Accordingly, in the second switching position b, the first hydraulic connection A is connected to the second line 22 and the second hydraulic connection B is connected to the first line 20.1, 20.2. In the in Fig. In the neutral position shown in Figure 1, both the first hydraulic port A and the second hydraulic port B are connected to the second line 22 and thus relieved of pressure to the tank. The first line 20.1, 20.2 is blocked in the neutral position. One or more hydraulic consumers, such as a hydraulic cylinder, can be connected to the hydraulic ports A and B in a known manner.

[0034] A pressure compensator 24 is also arranged in the first line 20.1, 20.2. The pressure compensator 24 is designed as a proportional pressure compensator 24 and regulates the flow to the slide valve 16 located downstream of the pressure compensator 24 and thus to the supplied hydraulic connection A or B. The pressure compensator 24 is thus designed as a so-called upstream pressure compensator 24, since it is arranged upstream of the slide valve 16 and downstream of the connection section 102. In the following, the reference numeral 20.1 is used for the part of the first line located upstream of the pressure compensator 24, and the reference numeral 20.2 is used for the part of the first line located downstream of the pressure compensator 24.

[0035] Furthermore, the hydraulic valve bank 100 has an LS (load sensing) system. For this purpose, the valve section 10 has a load pressure signaling channel 26 and a load pressure collection channel 28. The load pressure signaling channel 26 is connected to the load pressure collection channel 28 via a shuttle valve 30. This ensures that the highest load pressure occurring in the hydraulic valve bank 100 is always present in the load pressure collection channel 28. The load pressure collection channel 28 is connected to a bank load pressure channel 32 of the valve section 10 via a load pressure connecting line 114 in the connection block 102. A uniform pressure signal is provided for all valve sections 10 via the bank load pressure channel 32, which represents the highest load pressure occurring in the hydraulic valve bank 100.

[0036] As in Fig. 1, the load pressure signaling channel 26 downstream of the slide valve 16 is connected to the first hydraulic port A or the second hydraulic port B depending on the switching position a or b assumed. The currently applied load pressure of the valve section 10 is thus reported via the load pressure signaling channel 26 to the shuttle valve 30 and, if the height is sufficient to switch the shuttle valve 30, also to the load pressure collecting channel 32.

[0037] The pressure compensator 24 does not have a control spring for adjusting the pressure difference (Δp). Instead, a total of four pressure signals P1 to P4 are reported to the pressure compensator 24. For this purpose, the valve section has a first pilot line 23.1, which branches off from the first line 20.2 downstream of the pressure compensator 24 and is connected to the pressure compensator on the control side. A first pressure signal P1 is thus reported to the pressure compensator 24 via the first pilot line 23.1 on the control side. A second pilot line 23.2 branches off from the load pressure signal channel 26 and is connected to the pressure compensator 24 on the control side. A second pressure signal P2 is applied to the pressure compensator on the control side via the second pilot line 23.2, as will be described in more detail below. A third pilot line 23.3 branches off from the association load pressure channel 32 and is connected to the pressure compensator 24 on the control side. A third pressure signal P3 is thus reported to the pressure compensator 24 on the control side.A fourth pilot line 23.4 branches off from the first line 20.1 upstream of the pressure compensator 24 and is connected to the pressure compensator 24 on the upstream side. A fourth pressure signal P4 is thus transmitted to the pressure compensator 24 on the upstream side. A fifth pilot line 23.5 branches off from the first line 20.2 downstream of the pressure compensator 24 and is connected to the second pilot line 23.2.

[0038] As in Fig. 1, a first hydraulic resistance 34 is arranged in the fifth pilot line 23.5. In this embodiment, the first hydraulic resistance 34 is a first, adjustable nozzle. Furthermore, a second hydraulic resistance 36 in the form of a second nozzle is arranged in the second pilot line 23.2. As can be seen from the Fig. As can be seen from the circuit shown in Figure 1, the first nozzle 34 and the second nozzle 36 are connected in series in the form of a nozzle chain.

[0039] In Fig. 1, a third hydraulic resistance 38 is also provided, which influences the first pressure signal P1. The third hydraulic resistance 38 can be a third nozzle and possibly dampens vibrations occurring at the pressure compensator 24. Furthermore, a fourth hydraulic resistance 116 in the form of a fourth nozzle is provided in the load pressure connection line 114, which has a damping function.

[0040] Thus, the pressure compensator 24 does not receive the currently applied load pressure of the valve section 10 and the regulated pressure (via pressure signal P1), as is the case with known pressure compensators. Instead, a pressure signal dependent on the highest load pressure currently present in the system (via pressure signal P3) and the pump pressure present in the pressure channel 12 (via pressure signal P4) are also reported to the pressure compensator 24. By reporting these pressure signals, a control spring for specifying the pressure difference Δp can be dispensed with. The second pressure signal P2 acting on the control side enables a type of "volume flow boost", since the Δp is increased due to the nozzle chain formed by the first nozzle 34 and the second nozzle 36, namely by a pressure amount resulting from the selection of the diameters of the first nozzle 34 and the second nozzle 36. Assuming a pressure without the fifth pilot line 23.5 and the nozzle chain, the first nozzle 34 and the second nozzle 36 can be selected such that the second pressure signal P2 increases the actual Δp by 3 bar to 9 bar, for example, by selecting both nozzles with a diameter of 0.8 mm. This enables a higher volume flow, for example, over 120 l / min, via the pressure compensator 24 compared to a conventional pressure compensator control.

[0041] This can be explained using an example. Downstream of the pressure compensator 24, for example, 106 bar can be present in the first line 20.2. Downstream of the spool valve 16, for example, 100 bar can be present at the first or second hydraulic connection A, B, due to the throttle point formed on the spool valve. These 100 bar are reported via the load pressure signaling channel 26. In the fifth pilot line 23.5, upstream of the first nozzle 34, 106 bar is also present. Upstream of the second nozzle 36, on the load pressure signaling channel 26 side, 100 bar is present. Due to the series connection of the first nozzle 34 and the second nozzle 36, with an appropriate selection of the diameters of the nozzles 34, 36, the pressure present in the second pilot line 23.2 or the second pressure signal P2 can be set, for example, to 103 bar.Therefore, this pressure is applied to the pressure compensator 24 on the control side and not the pressure of the load pressure signaling channel 26, which is 3 bar lower, as is the case in the prior art.

[0042] The design of the pressure compensator 24 is described below with reference to Fig. 2 and Fig. 3 is explained in more detail. Fig. 2 shows a first section through a valve section 10 and Fig. 3 shows a second section through the valve section 10.

[0043] As shown, the pressure compensator 24 has a pressure compensator housing 40. The pressure compensator housing 40 can be designed as a separate housing or can be an (integral) part of a housing 42 of the valve section 10. In this exemplary embodiment, the pressure compensator housing 40 is designed separately. The pressure compensator housing 40 has a piston bore 44, a control piston 46, a first auxiliary piston 48, a second auxiliary piston 50, and a plug 52. The control piston 46, the first auxiliary piston 48, and the second auxiliary piston 50 are arranged in the piston bore 44. The control piston 46 and the second auxiliary piston 50 are axially movable along a first axial direction R1. The spool piston 18 is arranged in a corresponding spool bore in the housing 42 of the valve section 10 and is axially movable along a second axial direction R2. As shown, the first axial direction R1 and the second axial direction R2 are not parallel to each other.Rather, the pressure compensator 24 is arranged transversely to the slide valve 16.

[0044] The plug 52 closes the piston bore 44 at one axial end of the piston bore 44, which is closer to the second auxiliary piston 50. The other axial end of the piston bore 44 is closed by the housing of an adjacent valve section (or by the connecting section 102) during assembly of the hydraulic valve bank 100. It is conceivable that the first auxiliary piston 48 is fixed to this adjacent housing or is formed integrally with it. The control piston 46 has a first guide surface 54, a second guide surface 56, and a circumferential recess 58 located between the first guide surface 54 and the second guide surface 56. A control edge 60 is formed at the transition between the first guide surface 54 and the recess 58. The first guide surface 54 and the second guide surface 56 are guided on corresponding inner circumferential surfaces of the piston bore 44. In the Fig. In the position of the control piston 46 shown in Figure 2, the control edge 60 completely blocks the first line 20.1. Upon movement of the control piston 46 in the direction of the plug 52, the control edge 60 increasingly releases the first line 20.1 with increasing movement of the control piston 46, thus increasing the flow area over which hydraulic fluid can flow via the first line 20.1 from the pressure channel 14 to the pressure compensator 24 and then further via the first line 20.2 to the slide valve 16. Thus, the control edge 60 defines the flow area of ​​the first line 20.1, 20.2 depending on the axial position of the control piston 46 relative to the piston bore 44.

[0045] The control piston 46 is guided on the first auxiliary piston 48. The second auxiliary piston 50 is positively connected to the control piston 46, as will be explained in more detail below. In this exemplary embodiment, the first auxiliary piston 48 and the second auxiliary piston 50 have an identical outer diameter. The control piston 46 has a first pot-like guide section 62, which engages with a second guide section 64 of the plug 52. As can be seen in Fig. As can be clearly seen in Figure 2, the second guide section 64 is arranged at least partially radially within the first guide section 62. This results in particularly good guidance of the control piston 46.

[0046] At the end of the second guide section 64, the plug 52 has a stop 66, against which the first guide section 62 of the control piston 46 abuts in an end position. Furthermore, it can be seen that the second auxiliary piston 50 is guided in the plug 52.

[0047] The control piston 46 has an eccentric bore 68 arranged within the first guide section 62. A partially circumferential collar 70 is provided at the end of the eccentric bore 68 facing the plug 52. The second auxiliary piston 50 has a circumferential receptacle 72 at its end facing the control piston 46, in which the collar 70 is received. For assembly, the second auxiliary piston 50 is moved along the eccentric bore 68 until the receptacle 72 is level with the collar 70. The second auxiliary piston 50 is then moved radially so that the collar 70 engages the receptacle 72. This creates a positive connection between the second auxiliary piston 50 and the control piston 46, so that the second auxiliary piston 50 and the control piston 46 move together.

[0048] The second auxiliary piston 50 and the plug 52 define a first chamber 74 in which the third pressure signal P3 is present. The first guide section 62 and the second guide section 64 define a second chamber 76 in which the first pressure signal P1 is present. The first pressure signal P1 is tapped from the first line 20.1 via a plurality of uniformly arranged first connecting lines 82 and reported to the second chamber 76. As shown, the first connecting lines 82 connect the second chamber 76 to the first line 20.1 by extending from the first guide surface 54 to the second chamber 76 in the form of at least one radial bore and at least one adjoining axial bore in the control piston 46.The control piston 46, the first auxiliary piston 48 and the pressure compensator housing 40 (as well as the adjacent component of the hydraulic valve bank 100 connected thereto) define a third chamber 78 in which the second pressure signal P2 is present. The control piston 46 and the first auxiliary piston 48 further define a fourth chamber 80 which is connected to the recess 58 via a plurality of evenly distributed second connecting lines 84 so that the pressure present upstream of the pressure compensator 24 in the first line 20.1 is reported to the fourth chamber 80 in the form of the fourth pressure signal P4. Since the first pressure signal P1 present in the second chamber 76 is always higher than the second pressure signal P2 present in the third chamber 78, the second pressure signal P2 only acts on the annular area formed by the end face of the control piston 46. The first auxiliary piston 48 does not move and remains in the position shown in . Fig. 2 shown position.

[0049] Due to this design of the pressure compensator 24, the pressure compensator reacts not only to the local load pressure of the valve section 10, but also to the global load pressure of the hydraulic valve bank 100 (i.e., to the third pressure signal P3). If the load pressure of the valve section 10 is therefore lower than the highest load pressure in the hydraulic valve bank 100, the third pressure signal P3 is applied to the control piston 46 in the first chamber 74 on the control side via the second auxiliary piston 50, and the flow area of ​​the first line 20.1 released by the control edge 60 is thus reduced. Furthermore, the nozzle chain formed by the first nozzle 34 and the second nozzle 36 increases the Δp by a constant amount (for example, by 3 bar), so that the flow area defined by the control edge 60 enables a higher volume flow compared to a conventional pressure compensator.

[0050] Finally, it should be noted that the Fig.The exemplary embodiment shown in Figure 1 can also comprise additional valve sections that are not equipped with a pressure compensator 24 described above, but instead comprise a conventional pressure compensator, or a pressure compensator in which the fifth pressure signal is not reported to the pressure compensator. The terms used herein, such as "first," "second," or "third," do not specify a specific order, but serve solely to distinguish the individual elements conceptually. For example, if necessary, an embodiment can be provided that includes a fourth nozzle but no third nozzle. List of reference symbols 10 Valve section 12 pressure channels 14 Return channel 16 slide valve 18 slide pistons 20.n first line 22 second line 23.1 first pilot line 23.2 second pilot line 23.3 third pilot line 23.4 fourth pilot line 23.5 fifth pilot line 24 pressure balance 26 Load pressure signaling channel 28 Load pressure collection channel 30 shuttle valve 32 Bandage load pressure channel 34 first hydraulic resistance / first nozzle 36 second hydraulic resistance / second nozzle 38 third hydraulic resistance / third nozzle 40 pressure compensator housing 42 Valve section housing 44 piston bore 46 control pistons 48 first auxiliary piston 50 second auxiliary piston 52 plugs 54 first guide surface 56 second guide surface 58 Deepening 60 control edge 62 first guide section 64 second guide section 66 stop 68 eccentric bore 70 collars 72 recording 74 First Chamber 76 second chamber 78 Third Chamber 80 fourth chamber 82 first connecting line 84 second connecting line 100 hydraulic valve assembly 102 Connection section 104 End plate 106 Pump connection 108 Tank connection 110 inlet regulator 112 Pilot pressure valve 114 Load pressure connection line 116 fourth hydraulic resistance / fourth nozzle a first switching position A first hydraulic connection b second switching position B second hydraulic connection PA control pressure signal P1 first pressure signal P2 second pressure signal P3 third pressure signal P4 fourth pressure signal R1 first axial direction R2 second axial direction

Claims

[1] Valve section (10) for a hydraulic valve bank (100) with a pressure channel (12), a return channel (14), a load pressure signaling channel (26), a load pressure collecting channel (28) connected to the load pressure signaling channel (26), an association load pressure channel (32), a slide valve (16), a pressure compensator (24), a first hydraulic connection (A), a second hydraulic connection (B), a first line (20.1, 20.2) connecting the pressure channel (12) to the slide valve (16) and a second line (22) connecting the return channel (14) to the slide valve (16), wherein the pressure compensator (24) is arranged in the first line (20.1, 20.2), wherein the slide valve (16) is switchable into at least a first switching position (a) and a second switching position (b), wherein in the first switching position (a) the first hydraulic connection (A) is connected to the first line (20.1, 20.2) and the load pressure signaling channel (26) and the second hydraulic connection (B) is connected to the second line (22), wherein in the second switching position (b) the second hydraulic connection (B) is connected to the first line (20.1, 20.2) and the load pressure signaling channel (26) and the first hydraulic connection (A) is connected to the second line (22), wherein a first pilot line (23.1) connected to the pressure compensator (24) on the control side branches off between the pressure compensator (24) and the slide valve (16) and a first pressure signal (P1) is applied to the pressure compensator (24) on the control side, wherein a second pilot line (23.2) connects the pressure compensator (24) on the upstream side to the load pressure signaling channel (26) and a second pressure signal (P2) is applied to the pressure compensator (24) on the upstream side, wherein a third pilot line (23.3) connected to the pressure compensator (24) on the control side branches off from the association load pressure channel (32) and a third pressure signal (P3) is applied to the pressure compensator (24) on the control side, wherein a fourth pilot line (23.4) connected to the pressure compensator (24) on the control side branches off between the pressure channel (12) and the pressure compensator (24) and a fourth pressure signal (P4) is applied to the pressure compensator (24) on the control side, characterized by , that a fifth pilot line (23.5) branches off between the pressure compensator (24) and the slide valve (16), wherein the fifth pilot line (23.5) is connected to the second pilot line (23.2), wherein a first hydraulic resistance (34) is arranged in the fifth pilot line (23.5), and wherein a second hydraulic resistance (36) is arranged in the second pilot line (23.2). [2] Valve section (10) according to claim 1, characterized by that the first hydraulic resistance (34) is a first nozzle and / or the second hydraulic resistance (36) is a second nozzle, wherein the first nozzle (34) is preferably an adjustable nozzle. [3] Valve section (10) according to claim 1 or 2, characterized by that the first pressure signal (P1) is damped via a third hydraulic resistance (38), wherein the third hydraulic resistance (38) is preferably a third nozzle. [4] Valve section (10) according to one of the preceding claims, characterized bythat the pressure compensator (24) has a pressure compensator housing (40) with a piston bore (44), a control piston (46), a first auxiliary piston (48) and a second auxiliary piston (50), wherein the control piston (46) is guided axially movably in the piston bore (44) and the control piston (46) is guided on the first auxiliary piston (48), and wherein the second auxiliary piston (50) is preferably positively connected to the control piston (46). [5] Valve section (10) according to claim 4, characterized by , that the control piston (46) has a first guide surface (54) guided in the piston bore (44), a second guide surface (56) guided in the piston bore (44) and an at least partially circumferential recess (58) located between the first guide surface (54) and the second guide surface (56), wherein a control edge (60) is formed at the transition between the first guide surface (54) and the recess (58), wherein the control edge (60) defines a flow area of ​​the first line (20.1, 20.2) depending on the axial position of the control piston (46) in the piston bore (44). [6] Valve section (10) according to claim 4 or 5, characterized by that the valve section (10) has a plug (52), wherein the second auxiliary piston (50) is guided axially in the plug (52) and defines a first chamber (74) with the plug (52), wherein the third pressure signal (P3) is present in the first chamber (74). [7] Valve section (10) according to claim 6, characterized by that the control piston (46) has a first guide section (62) and the plug (52) has a second guide section (64), wherein the first guide section (62) and the second guide section (64) engage with one another. [8] Valve section (10) according to claim 7, characterized byin that the first guide section (62) and the second guide section (64) define a second chamber (76), wherein the control piston (46) has at least one first connecting line (82) connecting the second chamber (76) to the first guide surface (54), wherein the first pressure signal (P1) is present in the second chamber (76). [9] Valve section (10) according to one of the preceding claims 4 to 8, characterized by that the control piston (46), the first auxiliary piston (48) and the pressure compensator housing (40) define a third chamber (78), wherein the second pressure signal (P2) is present in the third chamber (78). [10] Valve section (10) according to one of the preceding claims 4 to 9, characterized byin that the first auxiliary piston (48) and the control piston (46) define a fourth chamber (80), wherein the control piston (46) has at least one second connecting line (84) passing through the control piston (46) from the recess (58) into the fourth chamber (80), wherein the fourth pressure signal (P4) is present in the fourth chamber (80). [11] Valve section (10) according to one of the preceding claims 4 to 10, characterized by in that the control piston (46) is movable in a first axial direction (R1) and the slide valve (16) has a slide piston (18) movable in a second axial direction (R2), wherein the first axial direction (R1) and the second axial direction (R2) are not parallel. [12] Valve section (10) according to one of the preceding claims 4 to 11, characterized by , that the control piston (46) has an eccentric bore (68) with a collar (70) that only partially extends around it, wherein the second auxiliary piston (50) has a circumferential receptacle (72) at its end facing the control piston (46), wherein the partially circumferential collar (70) is at least partially arranged in the receptacle (72) when the second auxiliary piston (50) is positively connected to the control piston (46). [13] Hydraulic valve assembly (100) with at least one valve section (10) according to one of the preceding claims 1 to 12. [14] Hydraulic valve assembly (100) according to claim 13, characterized by , that the hydraulic valve assembly (100) has a connection section (102) connected to the valve section (10), wherein the load pressure signaling channel (26) is connected to the load pressure collecting channel (28) via a shuttle valve (30), and wherein the load pressure collecting channel (28) is connected to the dressing load pressure channel (32) via a load pressure connecting line (114) of the connecting section (102). [15] Hydraulic valve assembly (100) according to claim 14, characterized by that a fourth hydraulic resistance (116) is arranged in the load pressure connection line (114), wherein the fourth hydraulic resistance (116) is preferably a fourth nozzle.

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