Hydraulic valve group and mobile hydraulic system

Abstract

The invention relates to a hydraulic valve group 10 having at least two valve sections 12.1-12.5, a connecting section 14 and a pressure channel 16 for pressurizing the at least two valve sections 12.1-12.5. The pressure channel (16) connects the connection section (14) with each valve section (12.1-12.5) in order to pressurize the valve sections (12.1-12.5). Each valve section (12.1-12.5) has a valve spool (18.1-18.5), an electro-hydraulic pilot control (20.1-20.5) for actuating the valve spool (18.1-18.5), and an upstream pressure compensator (22.1-22.5). The hydraulic valve group 10 is configured as a load sensing system and has a load pressure acquisition channel 24 for signaling a maximum load pressure. A common pilot pressure signal can be applied to the respective electro-hydraulic pilot control (20.1 to 20.5) of each valve section (12.1 to 12.5) via the connection section (14). The hydraulic valve group 10 has a single pilot control pressure influencing valve 26 for changing the common pilot pressure signal, the pilot control pressure influencing valve 26 being connected to the pressure channel 16 in order to act on the pressure channel in a first switching direction, and the pilot control pressure influencing valve 26 being connected to the load pressure acquisition channel 24 in order to act on the pressure channel in a second switching direction. Therefore, the load pressure acquisition channel can be acted on along the second switching direction. The invention also relates to a mobile hydraulic system 1 having such a hydraulic valve group 10.

Description

Technical Field

[0001] The invention relates to a hydraulic valve group and a mobile hydraulic system having such a hydraulic valve group. Background Art

[0002] Such hydraulic valve groups are well known in the prior art. These hydraulic valve groups have several valve sections and connecting sections. Since a pressure channel connects the connecting section with each valve section, pressure can be applied to the valve sections via the pressure channel. Typically, each valve section has a valve core, an electrohydraulic pilot control for actuating the valve core, and an upstream pressure compensator. Via the connecting section, a common pilot pressure signal can be applied to the respective electrohydraulic pilot control of each valve section in order to move the respective valve core out of the neutral position and thus control the connected hydraulic consumer (e.g., a cylinder or a hydraulic motor).

[0003] An upstream pressure compensator is a pressure compensator that is arranged upstream of the valve core, as seen in the flow direction from the connecting section to the valve core. Such a hydraulic valve group is therefore configured as a load-sensing system and has a load pressure acquisition channel for signaling the highest load pressure present in the system. In other words, the highest load pressure in the system is reported from all valve sections to all pressure compensators in order to regulate the total volume requirement of the hydraulic system, since the valve section with the highest load pressure specifies the pump pressure to be set. The respective pressure compensator compares the load pressure of the corresponding valve section with the pump pressure. Via a spring element in the pressure compensator, a pressure difference between the load pressure of the valve section and the pump pressure is set. Due to the constant pressure difference, the volume flow depends only on the subsequent throttling cross section.

[0004] Such hydraulic valve blocks or hydraulic systems with upstream pressure compensator are used in various mobile hydraulic systems, such as forestry cranes, harvesters, feller bunchers or concrete pumps, because of their simple and sophisticated flow control.

[0005] However, a disadvantage of these hydraulic systems with upstream pressure compensators is their behavior in the case of undersupply, i.e. if 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 the case of such undersupply, the pressure compensator of the valve section with the highest load pressure may no longer regulate and fully open. This is because in the case of undersupply, the valve sections are supplied according to their load pressure, i.e. the valve section with the lowest load pressure is supplied first. As a result, the speed of the hydraulic consumers with high load pressures can be significantly reduced or even stagnant.

[0006] This control behavior in the event of an undersupply can be prevented by a downstream pressure compensator, which is also called "flow sharing". In such flow-sharing hydraulic systems, the pressure compensator is not arranged between the pump or the connection section and the valve spool, but between the valve spool and the hydraulic consumers. If an undersupply occurs in such a hydraulic system with a downstream pressure compensator, the flow rates of all valve sections to be supplied are proportionally reduced. As a result, the individual hydraulic consumers are not undersupplied and do not stagnate. However, the disadvantage of these hydraulic systems with downstream pressure compensators is the higher energy consumption and increased heating of the hydraulic oil. The use of hydraulic systems with downstream pressure compensators is much less attractive, especially in the rare event of an undersupply.

[0007] Therefore, in the case of undersupply, even in hydraulic systems with upstream pressure compensators, it is necessary to prevent individual hydraulic consumers from stagnating as much as possible. For this purpose, CH 700 344 B1 proposes a nozzle chain with additional valves for each valve section. Although this solution overcomes the disadvantages of the upstream pressure compensator in the case of undersupply, the additional valves, lines and nozzles mean that the expected costs of the hydraulic valve group are significantly higher. This also significantly increases the installation effort. Summary of the invention

[0008] It is therefore an object of the present invention to provide a hydraulic valve group with an upstream pressure compensator of simple construction, in which the hydraulic consumer does not stall even in the event of a supply shortfall.

[0009] This problem is solved by a hydraulic valve block according to claim 1. Preferred embodiments are described in the dependent claims.

[0010] Compared to the systems and hydraulic valve groups known in the prior art, the hydraulic valve group according to the invention is characterized in that it has a single pilot control pressure influencing valve for changing the common pilot pressure signal. According to the invention, the pilot control pressure influencing valve is connected to the pressure channel in order to act on the pressure channel in a first switching direction and is connected to the load pressure acquisition channel in order to act on the load pressure acquisition channel in a second switching direction.

[0011] In other words, the single pilot control pressure influencing valve compares the pump pressure with the highest load pressure present in the hydraulic system in order to influence or change the pilot pressure signal common to all valve sections. Therefore, no separate valve is required for each valve section, but the pilot pressure signal of all valve cores is adjusted globally by the pilot control pressure influencing valve. This is particularly advantageous if the hydraulic valve group has a sandwich design, such as the PSL product of the applicant. In this way, stagnation in the case of insufficient supply can be eliminated even if there are a large number of valve sections.

[0012] Preferably, the pilot control pressure influencing valve is configured such that in case of normal pump supply (pump pressure ≥ load pressure), a "normal" common pilot pressure signal is applied to the electrohydraulic pilot control part of the valve section. If an undersupply situation occurs (pump pressure < load pressure), the pilot pressure signal is adjusted, in particular globally adjusted and proportionally reduced. It is therefore particularly advantageous if the pilot control pressure influencing valve is a proportional pilot control pressure influencing valve.

[0013] Preferably, the hydraulic valve group also has a pilot control channel for applying a pilot control pressure signal to the corresponding electrohydraulic pilot control of each valve section, wherein the pilot control pressure influencing valve connects the pilot control channel to the pressure channel in a first switching direction and discharges the pilot control channel in a second switching direction. Discharge is understood in a known manner here to mean discharge via a return line to a tank. In this way, the pilot pressure signal can be adjusted proportionally to the pump pressure and the maximum load pressure.

[0014] Preferably, the pressure in the pilot control channel acts on the pilot control pressure influencing valve in the second switching direction. An undersupply may also lead to a drop in the pilot pressure signal. In order to prevent this, it is preferred if the regulated pilot pressure or the regulated pilot pressure signal acts on the pilot control pressure influencing valve in addition to the highest load pressure present in the system. It is also preferred if the pressure in the return line acts on the pilot control pressure influencing valve in the first switching direction.

[0015] It is advantageous if the effective areas of the individual pressures acting on the pilot control pressure-influencing valve are different. The behavior of the pilot control pressure-influencing valve can be adjusted precisely by selecting the effective areas or the ratio between the effective areas. As described above, the pressure in the pressure channel, the pressure in the load pressure acquisition channel, the pressure in the pilot control channel and the pressure in the return line can act on the pilot control pressure-influencing valve.

[0016] Preferably, the hydraulic valve group has at least one additional valve section connected to the pressure channel, an additional pilot pressure valve and an additional pilot control channel. The at least one additional valve section has a valve core, an electro-hydraulic pilot control unit for actuating the valve core and an upstream pressure compensator. The additional pilot pressure valve connects the additional pilot control channel to the pressure channel so that an additional pilot pressure signal or an additional pilot pressure can be applied to the electro-hydraulic pilot control unit of the additional valve section via the additional pilot control channel. In this case, it is particularly advantageous if the additional pilot pressure valve is a pressure control valve. Therefore, an additional pilot pressure signal independent of the pilot pressure signal is provided to the at least one additional valve section via a separate pilot circuit. This additional pilot pressure signal is not affected by the pilot control pressure influencing valve, so it is constant (e.g. 20 bar) even if the pump is undersupplied. This ensures that in the case of insufficient pump supply, the at least one additional valve section takes precedence over other valve sections. It is particularly advantageous if the pilot control pressure influencing valve is arranged in the connecting section. Preferably, the additional pilot pressure valve is arranged in the connecting section. As already mentioned above, the hydraulic valve group is usually designed as a sandwich structure, so that only the connection section is adapted to achieve the present invention. Therefore, the valve section of the known hydraulic valve group can be used without any adaptation.

[0017] As an alternative to directly reducing the pilot pressure signal, the pilot pressure signal may consist of a first pilot pressure signal and a second pilot pressure signal, the second pilot pressure signal acting in the opposite direction to the first pilot pressure signal. In other words, the first pilot pressure signal is a conventional pilot pressure signal known from the prior art, but in the case of undersupply, the first pilot pressure signal only constitutes a part of the total pilot pressure signal. In the case of undersupply of the pump, the entire pilot pressure signal then additionally consists of the second pilot pressure signal, which has the opposite effect. For example, if the first pilot pressure signal is always 20 bar, a second pilot pressure signal of, for example, 5 bar may reduce the total pilot pressure signal to 15 bar in the case of undersupply.

[0018] In this regard, it is preferred if the hydraulic valve group has a first pilot control channel for applying the first pilot control pressure signal to the corresponding electro-hydraulic pilot control part of each valve section, and the hydraulic valve group has a second pilot control channel for applying the second pilot control pressure signal to the corresponding electro-hydraulic pilot control part of each valve section. In simple terms, the following can be achieved: in the case of insufficient pump supply, the first pilot pressure signal moves the corresponding valve core from the neutral position in the first switching direction, while the second pilot pressure signal simultaneously "pushes back" the corresponding valve core in the direction of the neutral position.

[0019] Preferably, the pilot control pressure influencing valve is a proportional pilot control pressure influencing valve, and the second pilot control channel is connected to the pressure channel in the second switching direction, and the second pilot control channel is discharged in the first switching direction. This ensures that the second pilot pressure signal is 0 bar in the case of normal supply (pump pressure ≥ load pressure), and increases proportionally in the case of insufficient supply (pump pressure < load pressure).

[0020] Preferably, the hydraulic valve group has a pilot pressure valve, wherein the pilot pressure valve connects the first pilot control channel with the pressure channel. Therefore, the first pilot pressure signal is provided via the pilot pressure valve. Preferably, the pilot pressure valve should be a pressure control valve in order to obtain the required (e.g. 20 bar) first pilot pressure signal.

[0021] Preferably, a damping element is arranged in the second pilot control channel. This prevents unnecessary vibrations in the event of insufficient supply. It is also preferred if the nozzle is arranged in the load pressure acquisition channel upstream of the pilot control pressure influencing valve.

[0022] This problem can also be solved with a mobile hydraulic system according to claim 13, comprising a hydraulic valve block as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below with reference to the embodiments shown in the accompanying drawings. The accompanying drawings schematically show:

[0024] Figure 1 : A hydraulic circuit diagram of a mobile hydraulic system with a hydraulic valve group according to a first embodiment;

[0025] Figure 2 : A hydraulic circuit diagram of a mobile hydraulic system having a hydraulic valve group according to a second embodiment; and

[0026] Figure 3 : Hydraulic circuit diagram of a mobile hydraulic system with a hydraulic valve group according to a third embodiment. DETAILED DESCRIPTION

[0027] Figure 1 The hydraulic circuit diagram of a mobile hydraulic system 1 with a hydraulic valve group 10 according to a first embodiment is shown. In the present embodiment, the hydraulic valve group 10 has a connecting section 14, an end plate 34 and a total of five valve sections 12.1-12.5. A hydraulic consumer H.1-H.5 is connected to each valve section 12.1-12.5. As shown in the figure, the hydraulic consumers H1-H5 can be provided, for example, as synchronous cylinders, differential cylinders or hydraulic motors. The mobile hydraulic system 1 according to this exemplary embodiment can be used, for example, in a forestry work vehicle (not shown).

[0028] Each of the valve sections 12.1-12.5 has a proportional valve core 18.1-18.5 and a pressure compensator 22.1-22.n connected upstream of the valve core 18.1-18.5. Figure 1 The neutral position shown is moved to one of the switching positions a, b, each valve section 12.1-12.5 has an electrohydraulic pilot control 20.1-20.5 known per se. The electrohydraulic pilot control 20.1-20.5 is connected to a pilot control channel 28, via which a common pilot control pressure signal is emitted. The pilot pressure signal is described in more detail below. In addition, the electrohydraulic pilot control 20.1-20.5 is discharged to the return line R via the tank line T in a known manner.

[0029] In order to pressurize the hydraulic consumers H1-H5, a pressure channel 16 is provided, which connects the connecting section 14 to each valve section 12.1-12.5. The pressure from a pump (not shown) is usually distributed via the pressure channel 16 to the individual valve sections 12.1-12.5.

[0030] In addition, the hydraulic valve group 10 has a load pressure acquisition channel 24. The highest load pressure of the mobile hydraulic system 1 is reported to the load pressure acquisition channel 24 via the corresponding shuttle valves 31.1-32.5 and from the load pressure acquisition channel to the pump controller (not shown). In addition, in a known manner, the load pressure of the individual valve sections 12.1-12.5 is reported to the corresponding pressure compensators 22.1-22.5 in order to achieve a volume flow control that is independent of the overall load for the corresponding hydraulic consumers H1-H5. Therefore, the hydraulic valve group 10 according to the first embodiment is configured as a load sensing system in a known manner.

[0031] Likewise Figure 1 As shown, the load pressure collection passage 24 is discharged to the return line R together with the tank line T in the end plate 34 , and is further discharged to the tank via a spring-loaded check valve provided at the return line.

[0032] In order to prevent one or more hydraulic consumers H1-H5 from stalling in the event of undersupply, i.e. if the volume flow of the pump is less than the sum of the quantities requested by the hydraulic consumers H1-H5, the hydraulic valve group 10 comprises a single or only a pilot control pressure influencing valve 26. As shown in the figure, the pilot control pressure influencing valve 26 is arranged in the connecting section 14. The pressure prevailing in the pressure channel 16 is signaled to the pilot control pressure influencing valve 26 in such a way that this acts in a first switching direction. In addition, the pressure prevailing in the load pressure collection channel 24 is also signaled to the pilot control pressure influencing valve 26 via the nozzle 30, so that this acts in a second switching direction, which is opposite to the first switching direction. In addition, the pressure in the pilot control channel 28 is also reported to the pilot control pressure influencing valve 26, wherein this acts in addition to the pressure in the load pressure collection channel 24 and thus acts in the second switching direction. In addition, the pressure in the return line R is reported to the pilot control pressure influencing valve 26, wherein this pressure acts in addition to the pressure in the pressure channel 16 and thus acts in the first switching direction. As Figure 1 As shown, the effective areas of the various pressures acting on the pilot control pressure influencing valve are different, so that the behavior of the pilot control pressure influencing valve 26 can be specifically adjusted by selecting the effective area.

[0033] The pilot control pressure influencing valve 26 is configured as a proportional three-way / two-way valve with a pressure control function and connects the pilot control channel 28 to the pressure channel 16 on the one hand or to the return line R to the tank on the other hand. Depending on the switching position of the pilot control pressure influencing valve 26, the pilot control channel 28 is therefore not completely vented or is at least partially vented.

[0034] In the case of normal pump supply, the pump pressure acting in the first switching direction is greater than the total pressure reported to the pilot control pressure influencing valve 26 and prevailing in the load pressure acquisition channel 24 and the pilot control channel 28, so that the entire pilot pressure reaches the pilot control channel 28 via the pilot control pressure influencing valve 26. This allows the valve core 18.1-18.5 to be moved from the neutral position to the required switching position according to the user requirements of the mobile hydraulic system 1. The pilot pressure or the pilot pressure signal can be, for example, 20 bar.

[0035] In the event of a pump undersupply, the pump pressure acting in the first switching direction is lower than the sum of the pressures prevailing in the load pressure acquisition channel 24 and the pilot control channel 28, so that the pilot control channel 28 is discharged proportionally in this ratio. As a result, the pilot pressure signal decreases and is now only, for example, 15 bar. This in turn means that the valve spool 18.1-18.5 cannot be moved as required, but at least in those valve sections 12.1-12.5 where high load pressures prevail, the corresponding valve spool 18.1-18.5 can only be moved to a smaller extent from the neutral position. This prevents one or more upstream pressure compensators 22.1-22.5 from opening completely and making control impossible.

[0036] refer to Figure 2 , a mobile hydraulic system 1 with a hydraulic valve group 110 according to a second embodiment is described below. With regard to the valve sections 12.1-12.5, the configuration of the hydraulic valve group 110 according to the second embodiment is identical to the configuration of the hydraulic valve group 10 according to the first embodiment. As described above, hydraulic consumers H1-H5 are connected to each valve section 12.1-12.5, which can be actuated in a known manner via valve cores 18.1-18.5.

[0037] The hydraulic valve group 110 according to the second embodiment is different from the hydraulic valve group 10 according to the first embodiment in terms of the configuration of the connecting section 114 and the end plate 134. In addition, the hydraulic valve group 110 according to the second embodiment has an additional section 138, which is mounted on the connecting section 14 via a flange in the present exemplary embodiment. Of course, the additional section 138 can also be mounted on the end plate 134 via a flange.

[0038] A pilot pressure valve 132 connected to the pressure channel 16 and configured as a pressure control valve is arranged in the connecting section 114, and sends a common first pilot pressure signal of, for example, 20 bar to the electro-hydraulic pilot control parts 20.1-20.5 of each valve section 12.1-12.5 via the first pilot control channel 130.

[0039] In addition, a single pilot control pressure-affecting valve 126 is arranged in the additional section 138. The prevailing pressure in the pressure channel 16 is reported to the pilot control pressure-affecting valve 126 in such a way that this acts in the first switching direction. In addition, the prevailing pressure in the load pressure acquisition channel 24 is also reported to the pilot control pressure-affecting valve 126 via the nozzle 30, so that the latter acts in the second switching direction, which is opposite to the first switching direction. In addition, the pilot control pressure-affecting valve 126 has a biasing element 140, which also biases the pilot control pressure-affecting valve 126 in the second switching direction so as to balance the pressure difference between the maximum pump pressure and the maximum load pressure under normal supply. As shown in the figure, the biasing element 140 can be configured as an adjustable spring.

[0040] In this exemplary embodiment, the pilot control pressure influencing valve 126 is configured as a proportional three-way / two-way valve with a pressure control function. Depending on the switching position of the pilot control pressure influencing valve 126, the second pilot control channel 130 can be connected to the pressure channel 16 or the return line R via the pilot control pressure influencing valve 126. It should be noted here that the second pilot control channel 130 corresponds substantially to the tank line T of the hydraulic valve group 10 according to the first embodiment, so that conventional and known valve sections 12.1-12.5 can also be used in this embodiment. However, in contrast to the first embodiment, the second pilot control channel 130 is not discharged to the return line R in the end plate 134. Instead, the pressure is discharged to the return line R via the additional section 138 or via the pilot control pressure influencing valve 126 arranged therein.

[0041] During normal pump supply, the pump pressure applied to the pilot control pressure influencing valve 126 exceeds the sum of the preload pressure of the preload element 140 applied to the pilot control pressure influencing valve 126 and the highest load pressure in the load pressure acquisition channel 24. Therefore, the pilot control pressure influencing valve 126 completely connects the second pilot control channel 130 with the return line R. Therefore, the electro-hydraulic pilot control part 20.1-20.5 is discharged to the return line R via the second pilot control channel 130 and the pilot control pressure influencing valve 126. In addition, the first pilot pressure signal reported via the pilot pressure valve 132 is present in the first pilot control channel 128, so that the valve core 18.1-18.5 can be moved from the neutral position to the required switching position according to the user requirements of the mobile hydraulic system 1.

[0042] If a pump undersupply situation occurs, the pump pressure in the pressure channel 16 drops below the sum of the preload pressure of the preload element 140 and the load pressure signaled to the pilot control pressure influencing valve 126. As a result, the second pilot control channel 130 is at least partially connected to the pressure channel 16, whereby a second pilot control pressure signal is present in the second pilot control channel 130. This second pilot pressure signal acts in the opposite direction to the first pilot pressure signal on the electro-hydraulic pilot control 20.1-20.5 and accordingly "pushes back" the spool 18.1-18.5. In other words, if the first pilot pressure signal is, for example, 20 bar and the second pilot pressure signal is, for example, 5 bar, a total pilot pressure signal of 15 bar is reported to the electro-hydraulic pilot control 20.1-20.5. This in turn means that the valve spool 18.1-18.5 cannot be moved as required, but at least in the valve section 12.1-12.5 where high load pressures prevail, the corresponding valve spool 18.1-18.5 can only be moved more slightly from the neutral position. This prevents one or more upstream pressure compensators 22.1-22.5 from opening completely and making control impossible.

[0043] In order to prevent the pressure peak from occurring in the second pilot control channel 130, the following can be set in the second pilot control channel 130: Figure 2 The damping element 136 shown. It is not absolutely necessary for the pilot pressure influencing valve 126 and the damping element 136 to be arranged in the additional section 138. It is also possible to integrate these functions directly into the connecting section 114 or the end plate 134.

[0044] refer to Figure 3 , a mobile hydraulic system 1 with a hydraulic valve group 210 according to a third embodiment is described below. With regard to the valve sections 12.2-12.5, the configuration of the hydraulic valve group 210 according to the third embodiment is identical to the configuration of the hydraulic valve group 10 according to the first embodiment. As described above, hydraulic consumers H2-H5 are connected to each valve section 12.2-12.5, which can be actuated in a known manner via valve cores 18.2-18.5.

[0045] On the one hand, the hydraulic valve group 210 according to the third embodiment differs from the hydraulic valve group 10 according to the first embodiment in terms of the configuration of the connecting section 214. On the other hand, the hydraulic valve group 210 according to the third embodiment has at least one additional valve section 212.1. In the exemplary embodiment shown, there is exactly one additional valve section 212.1, which is directly adjacent to the connecting block 214 and represents an additional valve section 212.1, which is connected to the load pressure acquisition channel 24 and has an upstream pressure compensator 222.1. In addition, a second end plate 234 is provided. This additional valve section 212.1 will now be discussed in more detail.

[0046] The spool 218.1 of the additional valve section 212.1 can be moved in a known manner from a neutral position via the electrohydraulic pilot control 220.1 in order to pressurize or discharge the hydraulic consumer H1 connected to the additional valve section 212.1. However, the electrohydraulic pilot control 220.1 is not pressurized via the pilot pressure signal shared by the pilot control pressure influencing valve 226. Instead, the connecting section 214 has an additional pilot pressure valve 232 with a pressure control function. The pressure channel 16 can be connected to the additional pilot control channel 30 via the additional pilot control pressure valve 232, so that a constant additional pilot control pressure signal of, for example, 20 bar can be applied to the electrohydraulic pilot control 220.1 of the additional valve section 212.1. This additional pilot pressure signal is constant and is not influenced by the pilot control pressure influencing valve 226 even in the case of insufficient pump supply. Therefore, the consumer H1 connected to the additional valve section 212.1 can be processed with priority over other hydraulic consumers of the load sensing circuit. For example, the hydraulic consumer H1 connected to the additional valve section 212 . 1 can be a steering cylinder.

[0047] Reference numerals list 1. Mobile hydraulic system 10. Hydraulic valve group 12.n, valve section 14. Connecting segment 16. Pressure channel 18.n, valve core 20.n, electro-hydraulic pilot control unit 22.n、Pressure compensator 24. Load pressure acquisition channel 26. Pilot control pressure influence valve 28. Pilot control channel 30. Nozzle 32.n, shuttle valve 34. End plate 110. Hydraulic valve group 114. Connecting section 126. Pilot control pressure influence valve 128. First pilot control channel 130, Second pilot control channel 132. Pilot pressure valve 134. End plate 136. Damping element 138. Additional paragraph 140. Bias element 210. Hydraulic valve group 214. Connection section 212.n, additional valve section 218.1、Valve core 220.1、Electro-hydraulic pilot control unit 222.1. Pressure compensator 226. Pilot control pressure-influencing valve 228. Additional pilot control channel 232. Additional pilot pressure valve 234. End plate a. Valve core switching position b. Valve core switching position Hn, hydraulic consumers R. Return line T. Storage tank pipeline

Claims

1. A hydraulic valve group (10, 110, 210), comprising: At least two valve sections (12.1-12.5), connecting segments (14, 114, 214), and a pressure channel (16) for pressurizing the at least two valve sections (12.1-12.5), The pressure channel (16) connects the connecting section (14, 114, 214) to each valve section (12.1-12.5) so as to pressurize the valve sections (12.1-12.5). Each valve section (12.1-12.5) comprises a valve core (18.1-18.5), an electro-hydraulic pilot control unit (20.1-20.5) for actuating the valve core (18.1-18.5), and an upstream pressure compensator (22.1-22.5). The hydraulic valve group (10) is configured as a load sensing system and has a load pressure acquisition channel (24) for sending a signal of the highest load pressure, and wherein, via the connecting section (14, 114, 214), a common pilot pressure signal can be applied to the corresponding electro-hydraulic pilot control unit (20.1-20.5) of each valve section (12.1-12.5), It is characterized in that The hydraulic valve group (10, 110, 210) includes a single pilot control pressure influencing valve (26, 126, 226) for changing the common pilot pressure signal. The pilot control pressure influencing valve (26, 126, 226) is connected to the pressure channel (16) so as to act on the pressure channel in a first switching direction, and The pilot control pressure influencing valve (26, 126, 226) is connected to the load pressure collecting channel (24) so ​​as to act on the load pressure collecting channel along the second switching direction.

2. The hydraulic valve assembly (10) according to claim 1, It is characterized in that The hydraulic valve group (10) has a pilot control channel (28) for applying a pilot control pressure signal to the corresponding electro-hydraulic pilot control part (20.1-20.5) of each valve section (12.1-12.5), wherein the pilot control pressure influencing valve (26) is a proportional pilot control pressure influencing valve (26), and the pilot control channel (28) is connected to the pressure channel (16) along the first switching direction, and the pilot control channel (28) is discharged along the second switching direction.

3. The hydraulic valve assembly (10) according to claim 2, It is characterized in that The pressure in the pilot control channel (28) acts on the pilot control pressure influencing valve (26) in the second switching direction.

4. The hydraulic valve assembly (210) according to any one of the preceding claims, It is characterized in that The hydraulic valve group (210) comprises at least one additional valve section (212.1) connected to the pressure channel (16), an additional pilot pressure valve (232) and an additional pilot control channel (228), wherein the at least one additional valve section (212.1) comprises a valve core (218.1), an electro-hydraulic pilot control unit (220.1) for actuating the valve core (218.1) and an upstream pressure compensator (222.1), wherein the additional pilot pressure valve (232) connects the additional pilot control channel (228) to the pressure channel (16) so that an additional pilot pressure signal can be applied to the electro-hydraulic pilot control unit (220.1) of the additional valve section (212.1) via the additional pilot control channel (228), wherein the additional pilot pressure valve (232) is preferably a pressure control valve.

5. The hydraulic valve assembly (210) according to claim 4, characterized in that The additional pilot pressure valve (226) is arranged in the connecting section (14).

6. A hydraulic valve block (10) according to any one of the preceding claims, It is characterized in that The pilot control pressure influencing valve (26) is arranged in the connecting section (14).

7. The hydraulic valve assembly (110) according to claim 1, It is characterized in that The pilot pressure signal is composed of a first pilot pressure signal and a second pilot pressure signal, and the action direction of the second pilot pressure signal is opposite to that of the first pilot pressure signal.

8. The hydraulic valve assembly (110) according to claim 7, It is characterized in that The hydraulic valve group (110) has a first pilot control channel (128) for applying the first pilot control pressure signal to the corresponding electro-hydraulic pilot control part (20.1-20.5) of each valve section (12.1-12.5), and the hydraulic valve group (110) has a second pilot control channel (130) for applying the second pilot control pressure signal to the corresponding electro-hydraulic pilot control part (20.1-20.5) of each valve section (12.1-12.5).

9. The hydraulic valve assembly (110) according to claim 8, It is characterized in that The pilot control pressure influencing valve (126) is a proportional pilot control pressure influencing valve, and connects the second pilot control channel (130) with the pressure channel (16) along the second switching direction, and discharges the second pilot control channel (130) along the first switching direction.

10. The hydraulic valve assembly (110) according to claim 8 or 9, It is characterized in that The hydraulic valve group (110) has a pilot pressure valve (132), wherein the pilot pressure valve (132) connects the first pilot control channel (128) with the pressure channel (16), and wherein the pilot pressure valve (132) is preferably a pressure control valve.

11. The hydraulic valve assembly (110) according to any one of claims 8 to 10, It is characterized in that A damping element (136) is disposed in the second pilot control passage (130).

12. The hydraulic valve assembly (10, 110, 210) according to any one of the preceding claims, It is characterized in that The nozzle (30) is arranged in the load pressure collection passage (24) upstream of the pilot control pressure influencing valve (26, 126, 226).

13. A mobile hydraulic system (1) comprising a hydraulic valve block (10, 110, 226) according to any of the preceding claims.

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