CN117570071A - Valve part and hydraulic system with valve part - Google Patents

Abstract

The present invention relates to a valve part for a hydraulic system and a hydraulic system with the same, the valve part comprising at least a first hydraulic port and a second hydraulic port for supplying hydraulic fluid to a hydraulic consumer, the valve part having a valve core, a pressure channel and a collecting channel, wherein the pressure channel can be connected to a pump of the hydraulic system, the valve core selectively connecting the first hydraulic port to the pressure channel and the second hydraulic port to the collecting channel, or connecting the first hydraulic port to the collecting channel and the second hydraulic port to the pressure channel, an inlet pressure compensator being arranged between the pressure channel and the valve core, and an outlet pressure compensator being arranged between the valve core and the collecting channel, the inlet pressure compensator and the outlet pressure compensator being controllable via a signal pressure means, and an external additional component depending on the operating state of the hydraulic system acting on the hydraulic port connected to the collecting channel such that the inlet pressure compensator blocks the pressure channel.

Description

Valve part and hydraulic system with valve part

Technical Field

The present invention relates to a valve part for a hydraulic system and a hydraulic system having such a valve part. The hydraulic system is in particular suitable for a hydraulic system of a mobile hydraulic system.

Background

Such hydraulic systems are used in a variety of mobile hydraulic applications, such as ladders for fire trucks, excavators for earth working, municipal vehicles, garbage trucks, lin Yongqi cranes, loading cranes, concrete pumps, harvesters, container loading cranes, or other grapples. Common to these mobile hydraulic applications is to raise the load to move it from one place to another. For this purpose, mobile hydraulic applications have hydraulic consumers which are often configured as hydraulic cylinders or hydraulic motors. In particular differential cylinders are used as hydraulic cylinders.

To move the load, various movements are induced via the hydraulic consumers, such as lifting and lowering, tilting, rotating, turning, extending or grabbing. For this purpose, the hydraulic consumers are correspondingly pressurized via the hydraulic system, which is provided via a pump of the hydraulic system and distributed to the hydraulic consumers via corresponding valve portions. For this purpose, the valve part has at least a first hydraulic port and a second hydraulic port for supplying the hydraulic consumer with hydraulic fluid. Via the spool, the first hydraulic port may be selectively connected to the pressure passage and the second hydraulic port connected to the drain, or the first hydraulic port may be connected to the drain and the second hydraulic port connected to the pressure passage. In other words, one of the hydraulic ports is pressurized and the other hydraulic port is not pressurized.

In general, such hydraulic systems are also configured as so-called load sensing systems, in which the highest load pressure present in the system is signaled via a common load pressure channel. In order to control the volume flow to the individual hydraulic consumers, this load pressure is signaled to the pressure compensator of each valve part, so that the valve part 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 portion with the downstream pressure of the pressure compensator and the upstream pressure of the spool or spool edge, respectively. The pressure difference between the load pressure of the valve part and the downstream pressure of the pressure compensator and the upstream pressure of the spool edge is set via a spring element in the pressure compensator. Since the pressure differences are always equal, the volume flow is only dependent on the following throttle cross section of the valve element.

This type of hydraulic system configuration has proven itself in a variety of mobile hydraulic applications. However, there is still a requirement for increased energy, in particular due to the pressure compensator control. In general, therefore, it is desirable to consume as little energy as possible or that energy be "recycled" in such mobile hydraulic applications. This is particularly desirable if the energy supply for the hydraulic system is not provided by the combustion engine but by a battery. In particular in municipal sectors and loading cranes, electrified solutions have recently been increasingly used.

Disclosure of Invention

It is therefore an object of the present invention to provide a valve part for a hydraulic system, which valve part is operated in a particularly energy-efficient manner. Furthermore, the object of the invention is to provide a corresponding hydraulic system with at least one such valve part, and a mobile hydraulic system with a hydraulic system.

The problem is solved with a valve part according to claim 1. Preferred embodiments are described in the dependent claims.

The valve part for a hydraulic system according to the invention comprises at least a first hydraulic port and a second hydraulic port for supplying hydraulic fluid to at least one hydraulic consumer. Furthermore, the valve part comprises a valve core, a pressure channel and a collecting channel, wherein the pressure channel is connectable to a pump of the hydraulic system. The spool selectively connects the first hydraulic port to the pressure port and the second hydraulic port to the collection port, or connects the first hydraulic port to the collection port and the second hydraulic port to the pressure port. According to the invention, an inlet pressure compensator is arranged between the pressure channel and the valve cartridge, and an outlet pressure compensator is arranged between the valve cartridge and the collecting channel. The inlet pressure compensator and the outlet pressure compensator may be controlled via signal pressure means. An external additional force component at the first or second hydraulic port, depending on the operating state of the hydraulic system, acts on the signal pressure device to cause the inlet pressure compensator to block the pressure channel. In other words, the inlet pressure compensator then blocks the connection between the pressure channel and the valve spool. In particular, an external additional component acts on the hydraulic port connected to the collection channel.

In other words, if an external additional component force (e.g. pulling a load) is additionally acting in the desired direction of movement of the hydraulic consumer connected to the respective hydraulic port, the generated additional pressure signal is transmitted via the signal pressure means, so that the inlet pressure compensator cuts off the connection to the pressure channel and pressure is supplied to the actuated hydraulic port via the collecting channel. This saves energy since no pressure has to be supplied via the pump, but the collecting channel takes over a function similar to an accumulator.

Preferably, the signal pressure device comprises a first signal pressure line, wherein the first signal pressure line is connected to the first hydraulic port when the first hydraulic port is connected to the collecting channel via the spool, and wherein the first signal pressure line is connected to the second hydraulic port when the second hydraulic port is connected to the collecting channel via the spool.

Preferably, the signal pressure device comprises a second signal pressure line, wherein the second signal pressure line is connected to the first hydraulic port when the second hydraulic port is connected to the collection channel via the spool, and wherein the second signal pressure line is connected to the second hydraulic port when the first hydraulic port is connected to the collection channel.

Preferably, the signal pressure device has a third signal pressure line, which diverges between the inlet pressure compensator and the valve spool.

Preferably, the signal pressure device has a fourth signal pressure line, which diverges between the valve spool and the outlet pressure compensator.

Preferably, the pressure in the first signal pressure line is applied to the outlet pressure compensator on the closing control side.

Preferably, the first signal pressure line and the third signal pressure line are connected to each other via a first shuttle valve, which is connected to the inlet pressure compensator on the closing control side. The pressure applied to the first signal pressure line or the pressure applied to the third signal pressure line (depending on which of these two pressures is higher) is thus transmitted on the closing control side via the first shuttle valve signal to the inlet pressure compensator, i.e. in the closing direction of the inlet pressure compensator.

Preferably, the pressure in the second signal pressure line is applied to the inlet pressure compensator on the opening control side, i.e. in the opening direction.

Preferably, the second signal pressure line and the fourth signal pressure line are connected to each other via a second shuttle valve, wherein the second shuttle valve is connected to the outlet pressure compensator on the opening control side. As a result, the pressure applied to the second signal pressure line or the pressure applied to the fourth signal pressure line (depending on which of these two pressures is higher) is transmitted via the second shuttle valve signal to the outlet pressure compensator on the opening control side, i.e. in the opening direction of the outlet pressure compensator.

Preferably, the inlet pressure compensator has a first biasing element acting on the opening control side. Preferably, the outlet pressure compensator has a second biasing element acting on the opening control side.

The interconnection logic of the inlet pressure compensator and the outlet pressure compensator described above may be used to ensure that, in the case of possible external and additional force components, the inlet pressure compensator is completely closed and blocks the pressure channel, while the outlet pressure compensator is open and thus fed into the collecting channel.

It is further preferred that the valve part has a load pressure signal line, wherein the second signal pressure line is connected to the load pressure signal line via a third shuttle valve. The highest load pressure that acts globally in the entire hydraulic system is signaled via the load pressure signal line. If the load pressure in the second signal pressure line exceeds the load pressure of any downstream valve portion, this is transmitted to the load pressure signal line via the third shuttle valve signal. The pressure applied to the load pressure signal line is signaled to the supply regulator via a corresponding connection block or directly to the variable pump.

Preferably, the valve portion comprises a return channel connectable to a reservoir of the hydraulic system.

Preferably, the valve portion has a feed line opening into the collection channel. The outlet pressure compensator is expediently designed as a preferably proportional 3/3-way pressure compensator and is connected to the valve spool on the inlet side and to the feed line and the return channel on the outlet side. In other words, depending on the pressure signal signalled by the signal pressure means, the volume flow flowing from one of the hydraulic ports via the valve spool to the outlet pressure compensator may flow at least partly via the outlet pressure compensator into the feed line and thus into the collecting channel.

Alternatively, it is preferable that the valve portion has a feed line opening between the spool and the inlet pressure compensator. Preferably, the outlet pressure compensator is configured as a preferably proportional 3/3-way pressure compensator and is connected to the valve spool on the inlet side and to the feed line and the return channel on the outlet side. In other words, depending on the pressure signal signalled by the signal pressure means, the volume flow flowing from one of the hydraulic ports via the valve spool to the outlet pressure compensator can be at least partially returned directly downstream via the outlet pressure compensator to the inlet pressure compensator and can thus be "recycled".

Alternatively, it is preferred that the valve part has a feed line, wherein the outlet pressure compensator is configured as a 2/2-way pressure compensator and is connected to the valve spool on the inlet side and to the feed line on the outlet side, whereby the feed line opens into the collecting channel. In this way, hydraulic fluid flowing out via the outlet pressure compensator can be sent directly downstream via the collecting channel back to the inlet pressure compensator and can thus be "recycled".

In this context, it is preferred that the valve element is configured such that the volume flow to the hydraulic consumer, which varies as a function of the inlet area of the hydraulic consumer, is equal to or greater than the volume flow leaving the hydraulic consumer, which varies as a function of the outlet area of the hydraulic consumer. It is particularly preferred that the volume flow to the hydraulic consumer is greater than the volume flow leaving the hydraulic consumer. For example, if the hydraulic consumer is a double acting cylinder, the inlet area is either the piston side cylinder surface or the rod side cylinder surface, and thus the outlet area is the other of these two surfaces. This enables particularly stable control of the hydraulic consumer, in particular if the outlet pressure compensator is configured as a 3/3-way pressure compensator.

Preferably, a feed line check valve opening in the direction of flow leaving the outlet pressure compensator is provided in the feed line. In this way, backflow to the outlet pressure compensator can be reliably prevented.

Preferably, the collecting channel is a return channel, wherein the valve part is provided with suction means. Preferably, the return channel is then preloaded to achieve sufficient pressure storage. Preferably, the suction means connects the return passage to the first hydraulic port and the second hydraulic port.

Alternatively, it may be preferred that the valve portion comprises an inhalation device, wherein the inhalation device connects the collection channel to the first hydraulic port and the second hydraulic port.

Here, it is preferable that the suction device has a first suction line with a first suction valve and a second suction line with a second suction valve, wherein the first suction line opens between the spool and the first hydraulic port, and wherein the second suction line opens between the spool and the second hydraulic port.

Alternatively, it is preferred that the valve part has an inhalation device with a third inhalation line with a third inhalation valve, which diverges between the inlet pressure compensator and the valve cartridge and opens into the collecting channel.

Preferably, the suction device has a first protection line with a first pressure relief valve, which branches off between the valve element and the first hydraulic port (a) and opens into the return channel. Therefore, it is preferable that the suction device has a second protection line with a second relief valve, which branches off between the spool and the second hydraulic port and opens into the return channel.

Preferably, the valve portion has a bypass line connecting the first hydraulic port and/or the second hydraulic port to the collection channel via the spool and bypassing the outlet pressure compensator. In particular, the bypass line connects the corresponding hydraulic port directly to the return passage, bypassing the outlet pressure compensator. In other words, depending on the switching position of the spool, one of the two hydraulic ports may be directly connected to the return passage via the bypass line, so that the discharged hydraulic fluid unsuitable for recycling may be directly discharged to the reservoir. This further saves energy by not discharging via the outlet pressure compensator.

Preferably, a pilot-controlled first check valve that opens in the flow direction of the spool is provided between the spool and the first hydraulic port, and a pilot-controlled second check valve that opens in the flow direction of the spool is provided between the spool and the second hydraulic port. The pressure applied to the second hydraulic port unlocks the first check valve, and the pressure applied to the first hydraulic port unlocks the second check valve. The check valve replaces the load holding valve that would otherwise have to be provided, which is generally more energetically advantageous, since when the load decreases, only the back-up pressure of the pump is needed to unlock the corresponding check valve.

Furthermore, the problem is solved with a hydraulic system according to claim 26. Preferred embodiments are described in the dependent claims.

The hydraulic system according to the invention comprises at least one valve part according to the invention as described above and a pump and a reservoir. The pressure channel of the valve part is connected to the pump and the return channel is connected to the reservoir. Of course, the hydraulic system may comprise two or more valve parts according to the invention, whereby the valve parts do not need to be identical in structure. For example, it may be preferable that the outlet pressure compensator of one valve portion is connected to the return channel, and the outlet pressure compensator of the other valve portion is connected to the collection channel.

Here, it is preferable that the hydraulic system includes an intermediate portion having a preload valve that preloads a collection passage configured as a return passage to a predetermined pressure.

Alternatively, it is preferred that the hydraulic system comprises an intermediate part comprising a filling line with a filling valve, which filling line connects the pressure channel with the collecting channel. In this respect, it is preferred that the intermediate portion comprises a drain line with a drain valve, said drain line connecting the collecting channel to the return channel. For example, the filling valve may be set to 10 bar and the downstream suction valve to 9 bar. It can thus be ensured that the collecting channel is always preloaded with the desired pressure.

The intermediate portion may be configured as a separate portion, either as part of the connection block or also as part of the valve portion. A plurality of intermediate portions may also be provided.

Furthermore, it is preferred that the hydraulic system has a first connection line for connecting the at least one hydraulic consumer to the first pressure port and a second connection line for connecting the at least one hydraulic consumer to the second pressure port. The first flow control valve, which is preferably configured as a drop brake valve or a first line break protection device, is arranged in the first connecting line, and the second flow control valve, which is preferably configured as a second drop brake valve or a second line break protection device, is arranged in the second connecting line. It is particularly preferred that the load holding valve to be provided in practice is replaced by a pilot-controlled non-return valve. In addition, this improves safety and prevents uncontrolled decline of the increased load.

With the valve part according to the invention or the hydraulic system according to the invention, on the one hand, in the case of an external additional component force, energy can be saved by blocking the pressure channel. Furthermore, the collecting channel can be used to provide a channel preloaded to the desired pressure, i.e. configured in the manner of an accumulator via which the exiting hydraulic fluid is recirculated.

Of course, blocking the pressure channel in the sense of the invention may also be used independently of the recirculation of hydraulic fluid via the collecting channel. Thus, the collecting channel can also be realized without blocking the pressure channel. Furthermore, the various valve portions described above may be combined in any number and manner as desired to accommodate the desired function.

The problem is finally solved with a mobile hydraulic system according to claim 31. The mobile hydraulic system according to the invention has the hydraulic system described above.

Drawings

Hereinafter, the present invention is explained in more detail based on exemplary embodiments shown in the drawings, in which:

fig. 1 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a first embodiment of the invention;

fig. 2 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a second embodiment of the invention;

fig. 3 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a third embodiment of the invention;

fig. 4 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a fourth embodiment of the invention;

fig. 5 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a fifth embodiment of the invention; and

Fig. 6 is a hydraulic circuit diagram of a mobile hydraulic system with a hydraulic system according to a sixth embodiment of the invention.

Detailed Description

Fig. 1 depicts a hydraulic circuit diagram of a mobile hydraulic system 200 with a hydraulic system 100 according to the present invention according to a first embodiment. In the exemplary embodiment, hydraulic system 100 has two valve portions 10. The hydraulic system 100 is a sandwich structure and further includes a middle portion 110, a connection block 122, and an end plate 124. In this embodiment, the connection block 122 includes a pressure relief valve 126. The pressure relief valve 126 reduces the pilot pressure of each valve portion 10 in a known manner. Furthermore, the connection block 122 and the end plate 124 are formed in a conventional manner, and thus need not be further described.

The hydraulic system 100 also includes a pump PU driven by a motor M. In addition, the hydraulic system 100 has a tank T from which the pump PU draws hydraulic fluid and supplies it to the connection block 122. In this exemplary embodiment, pump PU is configured as a variable displacement pump. In this exemplary embodiment, the configuration of the valve portions 10 is the same, and therefore only one of the two valve portions 10 is described below.

The valve part 10 has a first hydraulic port a and a second hydraulic port B for supplying hydraulic fluid to at least one hydraulic consumer V of the mobile hydraulic system 200. In this embodiment, the hydraulic consumer V is a differential cylinder.

Further, the valve portion 10 includes a valve core 12 and a pressure passage 14 connected to a connection block 122 via an intermediate portion 110 in a conventional manner. The inlet pressure compensator 16 controls the supply of hydraulic fluid from the pressure passage 14 to the spool 12, as will be described in more detail below. In this embodiment, the inlet pressure compensator 16 is a proportional 2/2-way pressure compensator. Further, the valve portion 10 has a collection passage formed as a return passage R. The spool 12 is connected to the return passage R via an outlet pressure compensator 18. In this embodiment, the outlet pressure compensator 18 is configured as a proportional 2/2-way pressure compensator. The spool 12 may be proportionally moved from the neutral position shown in fig. 1 to the first or second switching position. In the first switching position, the spool 12 connects the pressure passage 14 to the first hydraulic port a and the second hydraulic port B to the return passage R. Correspondingly, in the second switching position, the spool 12 connects the pressure passage 14 to the second hydraulic port B and the first hydraulic port a to the return passage R. The inflow or outflow of hydraulic ports a and B is controlled via an inlet pressure compensator 16 and an outlet pressure compensator 18.

Thus, the valve portion 10 includes a signal pressure device 20. The signal pressure device 20 comprises a first signal pressure line 22, which is connected to the first hydraulic port a when the spool 12 is in the second switching position, i.e. when the first hydraulic port a is connected to the return channel R via the spool 12. Accordingly, when the spool 12 is in the first switching position, i.e., when the second hydraulic port B is connected to the return passage R via the spool 12, the first signal pressure line 22 is connected to the second hydraulic port B. The signal pressure device 20 further comprises a second signal pressure line 24 which is connected to the first hydraulic port a when the spool 12 is in the first switching position, i.e. when the second hydraulic port B is connected to the return channel R. Accordingly, when the spool 12 is in the second switching position, i.e., when the first hydraulic port a is connected to the return passage R, the second signal pressure line 24 is connected to the second hydraulic port B. The signal pressure device 20 includes a third signal pressure line 26 that diverges between the inlet pressure compensator 16 and the spool 12. In addition, the signal pressure device 20 has a fourth signal pressure line 28, which diverges between the valve spool 12 and the outlet pressure compensator 18.

The pressure in the first signal pressure line 22 is signaled to the outlet pressure compensator 18 on the closing control side. Further, the first signal pressure line 22 is connected to the third signal pressure line 26 via a first shuttle valve 30. The corresponding higher pressure is signaled to the inlet pressure compensator 16 via the first shuttle valve 30 on the closing control side. The pressure in the second signal pressure line 24 is transmitted to the inlet pressure compensator 16 on the opening control side and acts together with the first biasing element 34 in the opening control direction of the inlet pressure compensator 16. The second signal pressure line 24 is also connected to the fourth signal pressure line 28 via a second shuttle valve 32. The corresponding higher pressure is transmitted on the opening control side via the second shuttle valve 32 signal to the outlet pressure compensator 18 and acts together with the second biasing element 36 in the opening control direction of the outlet pressure compensator 18.

Further, the second signal pressure line 22 is connected to the load pressure signal line LS of the valve portion 10 via the third shuttle valve 38. Via the third shuttle valve 38, the highest load pressure of the hydraulic system 100 is signaled for pump control in a conventional manner.

In addition, the valve portion 10 includes an inhalation device 40. The inhalation device 40 has a first inhalation line 42 and a second inhalation line 44. A first suction valve 46, which in the exemplary embodiment is configured as a spring-loaded check valve, is disposed in the first suction line 42. Correspondingly, a second suction valve 48 is provided in the second suction line 44, which in the exemplary embodiment is also configured as a spring-loaded check valve. The first suction line 42 connects the return flow passage R to the first hydraulic port a and opens downstream of the spool 12, as seen in the direction toward the first hydraulic port a. The second suction line 44 connects the return flow passage R to the second hydraulic port B and opens downstream of the spool 12, as seen in the direction toward the second hydraulic port B.

The inhalation device 40 further comprises a first protection wire 54 and a second protection wire 56. A first relief valve 58 is provided in the first protection line 54. A second relief valve 60 is provided in the second protection line 56. The first protection line 54 diverges downstream of the spool 12 as seen in the direction toward the first hydraulic port a, and opens into the return flow passage R. Correspondingly, the second protection line 56 diverges downstream of the spool 12 as seen in the direction toward the second hydraulic port B, and also opens into the return flow passage R. Thus, damage to the hydraulic system 100 may be prevented via the first or second relief valves 58 and 60.

The return channel R of the valve portion 10 is connected to the tank T via the intermediate portion 110. A pre-load valve 112 in the form of a spring-loaded check valve is provided in the intermediate portion 110. Via the pre-load valve 112, the pressure in the return channel R between the intermediate portion 110 and the end plate 124 may be pre-loaded to a predetermined pressure level or pressure, for example 10 bar or even 20 bar.

Next, the function of the hydraulic system 100 according to the present invention will be described.

During normal movements, for example for lifting a load, the inlet pressure compensator 16 and the outlet pressure compensator 18 are controlled via the signal pressure device 20, so that both the inlet pressure compensator 16 and the outlet pressure compensator 18 are open. For example, when the pulling load is pressurized at the first hydraulic port a as an external additional component on the hydraulic consumer V, the signal pressure device 20 controls the inlet pressure compensator 16 to close. In other words, with the hydraulic consumer V configured as a differential cylinder in this example embodiment, the external force additionally acts in the extending direction of the piston. This may occur, for example, when lowering elevated loads.

In this case, the signal pressure in the first signal pressure line 22 exceeds the pressure in the third signal pressure line 26 and the pressure acting on the inlet pressure compensator 16 on the opening control side, i.e. the pressure generated by the first biasing element 34 and the pressure in the second signal pressure line 24 also acting in the opening control direction of the inlet pressure compensator 16. In this case, since the pressure in the fourth signal pressure line 28 exceeds the pressure in the second signal pressure line 24, the second shuttle valve 32 is closed, so that the pressure transmitted to the outlet pressure compensator 18 on the open control side is higher than the pressure in the first signal pressure line 22 together with the force generated by the second biasing element 36. As a result, the inlet pressure compensator 16 is closed and the outlet pressure compensator 18 is open. Any different volumes of hydraulic fluid are sucked out directly from the preloaded return channel R via the suction device 40.

As a result, the hydraulic fluid discharged via the second hydraulic port B is not directly fed to the tank T via the return flow passage R and is again sucked in via the pump PU, but is directly "recycled". The return channel R is opened towards the tank T only if the pressure in the return channel R exceeds the pressure set at the pre-load valve 112.

In fig. 2, a hydraulic circuit diagram of a mobile hydraulic system 200 with a hydraulic system 100 according to the invention is shown according to a second embodiment.

The hydraulic system 100 according to the second embodiment differs from the hydraulic system 100 according to the first embodiment shown in fig. 1 in that a separate collecting channel S is provided in addition to the return channel R. In the valve portion 10 immediately adjacent to the intermediate portion 110 in fig. 2, the outlet pressure compensator 18 is connected to the return passage R as in the first embodiment. In the other valve part 10, the outlet pressure compensator 18 is connected to the collecting channel S, not to the return channel R. The suction means 40 of the two valve portions 10 are configured such that hydraulic fluid is directly absorbed from the collecting channel S by connecting the first suction line 42 and the second suction line 44 to the collecting channel S, respectively.

Furthermore, the hydraulic system 100 according to the second embodiment differs from the embodiment shown in fig. 1 in that a bypass line 62 is provided in the valve portion 10 (the valve portion 10 shown on the left in fig. 2), which connects the spool 12 directly to the return passage R, bypassing the outlet pressure compensator 18. In this case, the spool 12 is configured such that in the first switching position, i.e. when the first hydraulic port a is connected to the pressure channel 14 or the inlet pressure compensator 16, respectively, it connects the second hydraulic port B directly to the return channel R via the bypass line 62. In this way, when the hydraulic consumer V is pressurized via the first hydraulic port a, for example to lift a load, the hydraulic fluid flowing out via the hydraulic port B can be released directly via the return flow channel R.

Furthermore, the hydraulic system 100 according to the second embodiment differs from the embodiment shown in fig. 1 in that in the valve portion 10 shown on the right in fig. 2, the connection of the outlet pressure compensator 18 is configured differently. The outlet pressure compensator 18 is not directly connected to the return channel R, but to the collecting channel S via a feed line 64. Thus, when the second hydraulic port B is pressurized, the first hydraulic port a is directly connected to the collection channel S via the outlet pressure compensator 18 to directly feed hydraulic fluid, which flows back and is pressurized (e.g., when lowering the load applied to the hydraulic consumer V) to the collection channel S and thus "recycles" it, as described above with reference to fig. 1. In conjunction with the bypass line 62, this makes it possible to guide the returning hydraulic fluid into the collecting channel S only when the hydraulic consumer V is retracted or only when the hydraulic consumer V is extended.

Further, the intermediate portion 110 is different from that shown in the first embodiment. Specifically, the intermediate portion 110 of the hydraulic system 100 according to the second embodiment includes a fill line 114 in which a fill valve 116 is disposed. Further, the intermediate portion 110 includes a drain line 118 having a drain valve 120 disposed therein. In this embodiment, the discharge valve 120 is configured as a spring-loaded check valve. The filling line 114 is connected on the one hand to the collecting channel S and on the other hand to the pressure channel 14 or the pump PU, respectively. The drain line 118 connects the collection channel S to the return channel R. Here, the filling valve 116 and the discharge valve 120 cooperate with each other so that there is always a desired preload in the collecting channel S. For example, the filling valve 116 may be set such that it ensures a minimum pressure of 9 bar in the collecting channel S. The discharge valve 120 is then arranged such that it opens, for example, at a pressure of 10 bar.

According to the second exemplary embodiment, the hydraulic fluid that may be returned is thus recovered into the collecting channel S only at those valve portions 10 in which an external additional component is also desired. This may be the case, for example, for a valve portion 10 through which a load is raised and lowered. In contrast, for example in the case of a valve part 10 which is responsible for rotation, an additional external component force is not desired, so that the outlet pressure compensator 18 of the valve part 10 can be connected directly to the return channel R.

A third embodiment of a mobile hydraulic system 200 with a hydraulic system 100 according to the invention is shown in fig. 3. The hydraulic system 100 according to the third embodiment differs from the exemplary embodiment shown in fig. 2 in the configuration of the suction device 40.

In the exemplary embodiment, inhalation device 40 has a third inhalation line 50 and a third inhalation valve 52 disposed in third inhalation line 50. In the exemplary embodiment, third suction valve 52 is configured as a spring-loaded check valve. The third suction line 50 diverges downstream of the inlet pressure compensator 16 and upstream of the spool 12 and opens into the collection channel S. If an additional external force component acts on the hydraulic consumer V, for example a pulling load, the inlet pressure compensator 16 closes as described above, thereby blocking the pressure channel 14. In this case, hydraulic fluid is drawn directly from the collection channel S via the third suction line 50 and directed via the spool 12 to the actuated hydraulic ports a and B.

In both the hydraulic system 100 according to the second embodiment and the hydraulic system 100 according to the third embodiment, the filling valve 116 provided in the intermediate portion 110 ensures that a sufficient amount of hydraulic fluid with a suitable preload remains available in the collecting channel S. Nevertheless, the collection channel S is filled via the filling valve 116 only when the preload in the collection channel S falls below the value set at the filling valve 116.

Fig. 4 shows a hydraulic circuit diagram of a mobile hydraulic system 200 according to a fourth embodiment.

In this embodiment, two identical valve parts 10 are shown as an example, which differ from the valve parts shown on the right in fig. 3 in the configuration and connection of the outlet pressure compensator 18. In the exemplary embodiment, outlet pressure compensator 18 is configured as a proportional 3/3-way pressure compensator and is connected to spool 12 on the input side. On the output side, the outlet pressure compensator 18 is connected on the one hand to the return channel R and on the other hand to the collecting channel S via a feed line 64. Depending on the pressure signal applied to the outlet pressure compensator 18 and signalled via the signal pressure means 20 and the bias of the second biasing element 36, the outlet pressure compensator 18 connects the valve spool 12 to the return channel R and the feed line 64 in a first switching position, connects it only to the feed line in a second switching position, and completely blocks the connection in a third switching position. Depending on the pressure signal signalled via the signal pressure means 20, the hydraulic fluid flowing back via the valve spool 12 can be released at least partly via the return flow channel R directly towards the tank T or completely supplied to the collecting channel S. Compared to the configuration shown in fig. 2, no bypass is necessary.

As shown, a feed line check valve 70 is provided in the feed line 64 to prevent backflow from the collection channel S through the outlet pressure compensator 18.

Further, the intermediate portion 110 is configured differently in this exemplary embodiment. Instead of the filling valve 116 and the discharge valve 120, a collecting valve 136 configured as a 3/2 way valve is provided in this embodiment. When the pressure in the collection channel S rises above the set level, the collection valve 136 releases the collection channel S to the tank T via the return channel R.

Thus, a constant pilot pressure in the collecting channel S, for example 20 bar, can be achieved via the third suction valve 52 and the collecting valve 136. Therefore, the pressure reducing valve 126 in the connection block 122 may also be omitted in this exemplary embodiment, since the pilot pressure signal of the valve part 10 is directly signal-transmitted via the collecting channel S.

Fig. 5 shows a hydraulic circuit diagram of a mobile hydraulic system according to a fifth embodiment. For simplicity, only the valve part 10 and the hydraulic consumers are shown here.

The embodiment shown in fig. 5 differs from the embodiment shown in fig. 4 in that the feed line 64 opens directly between the inlet pressure compensator 16 and the valve spool 12. No separate collecting channel S is provided. When retracting the hydraulic consumer V (configured as a cylinder), the hydraulic fluid flowing back via the first hydraulic port a is at least partially introduced directly via the feed line 64 downstream of the inlet pressure compensator 16 and supplied to the hydraulic consumer V via the second hydraulic port B. The hydraulic consumer V is then supplied with hydraulic fluid via the second hydraulic port B.

When the hydraulic consumer V configured as a cylinder is extended, the pressure applied via the inlet pressure compensator 16 blocks the feed line check valve 70, thereby releasing the outflow hydraulic fluid directly via the outlet pressure compensator 18 to the return channel R. Alternatively, however, it is also conceivable to provide pressure intensification, so that the returned hydraulic fluid is fed back directly downstream of the inlet pressure compensator 16 via the feed line 64.

Fig. 6 shows a hydraulic circuit diagram of a mobile hydraulic system according to a sixth embodiment. For simplicity, only the valve part 10 and the hydraulic consumers are shown here.

The valve portion 10 according to this sixth embodiment differs from the embodiment shown in fig. 4 on the one hand in that no protection lines 54 and 56 are provided and thus no corresponding relief valves 58 and 60 are provided either. However, embodiments with a protection line and a pressure relief valve are of course also conceivable. On the other hand, a first check valve 66 is provided between the spool 12 and the first hydraulic port a. As shown, the first check valve 66 blocks the direction of flow from the first hydraulic port a to the spool 12. Further, the first check valve 66 may be opened by the pressure applied to the second hydraulic port B. Accordingly, a second check valve 68 is provided between the spool 12 and the second hydraulic port B, which blocks the flow direction from the second hydraulic port B to the spool 12. The second check valve 68 may be opened by pressure applied to the first hydraulic port a.

As shown, the first check valve 66 is unlocked via a first control line 72 that is connected to the pressure passage 14 via the spool 12 when the spool 12 is in the switching position for pressurizing the second hydraulic port B (the upper switching position of the spool 12 in fig. 6). Accordingly, the second check valve 68 is unblocked via the second control line 74, which is connected to the pressure passage 14 via the spool 12 when the spool 12 is in the switching position for pressurizing the first hydraulic port a (the lower switching position of the spool 12 in fig. 6).

In this embodiment, the hydraulic consumer V is configured as a double cylinder and is connected to the first hydraulic port a via a first connection line 128 and to the second hydraulic port B via a second connection line 130. A first flow control valve 132 is disposed in the first connection line 128 and a second flow control valve 134 is disposed in the second connection line 130. In this embodiment, the first and second flow control valves 132, 134 are configured as 2-way flow control valves, which are also referred to as drop brake valves.

The combination of the hydraulic pilot-controlled check valves 66 and 68 and the drop brake valves 132 and 134 does not require separate load holding valves that would normally be provided in such a hydraulic arrangement. This is generally advantageous in terms of energy, since only the back-up pressure of the pump PU is required to reduce the load, since no pilot pressure is required to be generated via the pump PU to open the load holding valve. Only the corresponding check valves 66 and 68 must be opened via the only low pressure at the time.

The line break protection device may also be used in place of the flow control valves 132 and 134.

It should be noted that numerical terms such as "first," "second," "third," or "fourth" as used herein are not mandatory sequences, but are used merely to distinguish features or elements.

In addition, it should also be noted that the hydraulic system according to the invention may have a large number of different valve parts as described above, which may also be configured differently as desired. For example, the valve portion shown to the left in FIG. 2 may also be used in combination with the valve portion shown in FIG. 4. Furthermore, it is also contemplated that the outlet pressure compensator 18 shown in FIG. 6 is configured as a 3/3-way pressure compensator as shown in FIG. 4 or FIG. 5.

List of reference numerals

10. Valve part

12. Valve core

14. Pressure channel

16. Inlet pressure compensator

18. Outlet pressure compensator

20. Signal pressure device

22. First signal pressure line

24. Second signal pressure line

26. Third signal pressure line

28. Fourth signal pressure line

30. First shuttle valve

32. Second shuttle valve

34. First biasing element

36. Second preload element

38. Third shuttle valve

40. Inhalation device

42. A first suction line

44. A second suction line

46. First suction valve

48. Second suction valve

50. A third suction line

52. Third suction valve

54. First protective wire

56. Second protective wire

58. First pressure release valve

60. Second pressure release valve

62. Bypass line

64. Feed line

66. First check valve

68. Second check valve

70. Feed line check valve

72. First control line

74. Second control line

100. Hydraulic system

110. Intermediate portion

112. Preloading valve

114. Filling line

116. Filling valve

118. Discharging line

120. Discharge valve

122. Connecting block

124. End plate

126. Pressure reducing valve

128. First connecting wire

130. Second connecting wire

132. First flow control valve

134. Second flow control valve

136. Collecting valve

200. Mobile hydraulic system

A first hydraulic port

B second hydraulic port

LS load pressure signal line

M motor

R return channel

PU pump

S collecting channel

T storage tank

V-shaped hydraulic consumer

Claims (31)

1. Valve part (10) for a hydraulic system (100), the valve part (10) comprising at least a first hydraulic port (A) and a second hydraulic port (B) for supplying hydraulic fluid to at least one hydraulic consumer (V),

wherein the valve part (10) comprises a valve core (12), a pressure channel (14) and a collecting channel (R, S),

wherein the pressure channel (14) is connectable to a Pump (PU) of the hydraulic system (100),

wherein the spool (12) selectively connects the first hydraulic port (A) to the pressure passage (14) and the second hydraulic port (B) to the collection passage (R, S), or connects the first hydraulic port (A) to the collection passage (R, S) and the second hydraulic port (B) to the pressure passage (14),

Wherein an inlet pressure compensator (16) is arranged between the pressure channel (14) and the valve spool (12), and an outlet pressure compensator (18) is arranged between the valve spool (12) and the collector channel (R, S),

wherein the inlet pressure compensator (16) and the outlet pressure compensator (18) are controllable via a signal pressure device (20), and

wherein an external additional component, which depends on the operating conditions of the hydraulic system (100), acts on the signal pressure device (20) at the first hydraulic port (a) or the second hydraulic port (B) in order to cause the inlet pressure compensator (16) to block the pressure channel (14).

2. The valve portion (10) according to claim 1,

wherein the method comprises the steps of

The signal pressure device (20) comprises a first signal pressure line (22), wherein the first signal pressure line (22) is connected to the first hydraulic port (a) when the first hydraulic port (a) is connected to the collecting channel (R, S) via the spool (12), and wherein the first signal pressure line (22) is connected to the second hydraulic port (B) when the second hydraulic port (B) is connected to the collecting channel (R, S) via the spool (12).

3. The valve portion (10) according to claim 1 or 2,

Wherein the method comprises the steps of

The signal pressure device (20) comprises a second signal pressure line (24), wherein the second signal pressure line (24) is connected to the first hydraulic port (a) when the second hydraulic port (B) is connected to the collecting channel (R, S) via the spool (12), and wherein the second signal pressure line (24) is connected to the second hydraulic port (B) when the first hydraulic port (a) is connected to the collecting channel (R, S) via the spool (12).

4. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The signal pressure device (20) has a third signal pressure line (26), the third signal pressure line (26) diverging between the inlet pressure compensator (16) and the valve spool (12).

5. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The signal pressure device (20) has a fourth signal pressure line (28), the fourth signal pressure line (28) diverging between the valve spool (12) and the outlet pressure compensator (18).

6. The valve portion (10) according to any of the preceding claims 2 to 5,

wherein the method comprises the steps of

The pressure in the first signal pressure line (22) is applied to the outlet pressure compensator (18) on the closing control side.

7. The valve portion (10) according to any of the preceding claims 2 to 6,

wherein the method comprises the steps of

The first signal pressure line (22) and the third signal pressure line (26) are connected to each other via a first shuttle valve (30), the first shuttle valve (30) being connected to the inlet pressure compensator (16) on the closing control side.

8. The valve portion (10) according to any of the preceding claims 2 to 7,

wherein the method comprises the steps of

The pressure in the second signal pressure line (24) is applied to the inlet pressure compensator (16) on the opening control side.

9. The valve portion (10) according to any of the preceding claims 2 to 8,

wherein the method comprises the steps of

The second signal pressure line (24) and the fourth signal pressure line (28) are connected to each other via a second shuttle valve (32), the second shuttle valve (32) being connected to the outlet pressure compensator (18) on the opening control side.

10. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The inlet pressure compensator (16) has a first biasing element (34) acting on the opening control side.

11. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The outlet pressure compensator (18) has a second biasing element (36) acting on the opening control side.

12. The valve portion (10) according to any of the preceding claims 2 to 11,

wherein the method comprises the steps of

The valve part (10) comprises a load pressure signal Line (LS), wherein the second signal pressure line (24) is connected to the load pressure signal Line (LS) via a third shuttle valve (38).

13. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The valve part (10) comprises a return channel (R) connectable to a tank (T) of the hydraulic system (100).

14. The valve portion (10) according to claim 13,

wherein the method comprises the steps of

The valve part (10) has a feed line (64), the outlet pressure compensator (18) being configured as a 3/3-way pressure compensator and being connected to the valve spool (12) on the inlet side and to the feed line (64) and the return channel (R) on the outlet side, the feed line (64) opening into the collecting channel (S).

15. The valve portion (10) according to any of the preceding claims 1 to 12,

wherein the method comprises the steps of

The valve part (10) has a feed line (64), the outlet pressure compensator (18) being configured as a 3/3-way pressure compensator and being connected to the valve spool (12) on the inlet side and to the feed line (64) and the return channel (R) on the outlet side, the feed line (64) opening between the valve spool (12) and the inlet pressure compensator (16).

16. The valve portion (10) according to claim 14 or 15,

wherein the method comprises the steps of

The signal pressure device (20) controls the outlet pressure compensator (18) in the following manner: the outlet pressure compensator (18) is connected to the return channel (R) and the feed line (64) in a first switching position and to only the feed line (64) in a second switching position, and is disconnected from the feed line (64) and the return channel (R) in a third switching position.

17. The valve portion (10) according to claim 13,

wherein the method comprises the steps of

The valve part (10) has a feed line (64), the outlet pressure compensator (18) being configured as a 2/2-way pressure compensator and being connected to the valve spool (12) on the inlet side and to the feed line (64) on the outlet side, the feed line (64) opening into the collecting channel (S).

18. The valve portion (10) according to any of the preceding claims 1 to 12,

wherein the method comprises the steps of

The collecting channel is a return channel (R) connectable to a reservoir (T) of the hydraulic system (100), wherein the valve part (10) comprises an inhalation device (40), the inhalation device (40) connecting the return channel (R) to the first hydraulic port (a) and the second hydraulic port (B).

19. The valve portion (10) according to any of the preceding claims 13 to 17,

wherein the method comprises the steps of

The valve part (10) comprises an inhalation device (40), which inhalation device (40) connects the collecting channel (S) to the first hydraulic port (a) and the second hydraulic port (B).

20. The valve portion (10) according to claim 18 or 19,

wherein the method comprises the steps of

The suction device (40) comprises a first suction line (42) with a first suction valve (46) and a second suction line (44) with a second suction valve (48), wherein the first suction line (42) opens between the spool (12) and the first hydraulic port (a), and wherein the second suction line (44) opens between the spool (12) and the second hydraulic port (B).

21. The valve portion (10) according to any of the preceding claims 13 to 19,

wherein the method comprises the steps of

The valve part (10) has an inhalation device (40), the inhalation device (40) having a third inhalation line (50) with a third inhalation valve (52), the third inhalation line (50) diverging between the inlet pressure compensator (16) and the valve spool (12) and opening into the collecting channel (S).

22. The valve portion (10) according to any of the preceding claims 18 to 21,

wherein the method comprises the steps of

The suction device (40) has a first protection line (54) with a first pressure relief valve (58), the first protection line (54) diverging between the valve spool (12) and the first hydraulic port (A) and opening into the return channel (R).

23. The valve portion (10) according to any of the preceding claims 18 to 22,

wherein the method comprises the steps of

The suction device (40) has a second protection line (56) with a second pressure relief valve (60), the second protection line (56) diverging between the valve spool (12) and the second hydraulic port (B) and opening into the return channel (R).

24. The valve portion (10) according to any of the preceding claims,

wherein the method comprises the steps of

The valve part (10) has a bypass line (62), which bypass line (62) connects the first hydraulic port (a) and/or the second hydraulic port (B) to the collecting channel (R, S), in particular to the return channel (R), via the valve spool (12) and bypassing the outlet pressure compensator (18).

25. The valve portion (10) according to any of the preceding claims 1 to 21,

wherein the method comprises the steps of

A pilot-controlled first check valve (66) that opens in the fluid flow direction of the spool (12) is provided between the spool (12) and the first hydraulic port (A), and wherein a pilot-controlled second check valve (68) that opens in the fluid flow direction of the spool (12) is provided between the spool (12) and the second hydraulic port (B),

Wherein pressure applied to the second hydraulic port (B) unlocks the first check valve (66), and pressure applied to the first hydraulic port (a) unlocks the second check valve (68).

26. Hydraulic system (100) comprising at least one valve portion (10) according to any of the preceding claims, a Pump (PU) and a tank (T), wherein a pressure channel (14) is connected to the Pump (PU), and wherein a return channel (R) is connected to the tank (T).

27. The hydraulic system (100) according to claim 26,

wherein the method comprises the steps of

The hydraulic system (100) comprises an intermediate portion (110), the intermediate portion (110) comprising a pre-load valve (112), wherein the pre-load valve (112) pre-loads a collecting channel formed as a return channel (R) to a predetermined pressure.

28. The hydraulic system (100) according to claim 26,

wherein the method comprises the steps of

The hydraulic system (100) comprises an intermediate portion (110), the intermediate portion (110) comprising a filling line (114) with a filling valve (116), the filling line (114) connecting the pressure channel (14) to a collecting channel (S).

29. The hydraulic system (100) according to claim 28,

wherein the method comprises the steps of

The intermediate portion (110) comprises a drain line (118) with a drain valve (120), the drain line (118) connecting the collecting channel (S) to the return channel (R).

30. The hydraulic system (100) according to any one of the preceding claims 25 to 29,

wherein the method comprises the steps of

The hydraulic system (100) has a first connection line (128) for connecting at least one hydraulic consumer (V) to a first pressure port (a) and a second connection line (130) for connecting the at least one hydraulic consumer (V) to a second pressure port (B), wherein a first flow control valve (132) or a first line break protection device is provided in the first connection line (128) and wherein a second flow control valve (134) or a second line break protection device is provided in the second connection line (130), wherein the first flow control valve (132) is preferably a first drop brake valve (132) and wherein the second flow control valve (134) is preferably a second drop brake valve (134).

31. A mobile hydraulic system (200) comprising a hydraulic system (100) according to any of the preceding claims 26 to 30.