EP3058236B1 - Control apparatus - Google Patents

Description

The invention relates to a device with a control device in the manner of a valve block, in particular for the hydraulic control of components of mobile work machines.

Through the DE 42 30 183 C2 A control device for hydraulic motors is known, with at least one directional spool valve, which can be connected via an inlet line to a pump as a pressure supply device, via an outlet line to a tank or return connection and via at least one working line to one of the hydraulic motors, with an inlet regulator arranged in the inlet line , with a load pressure control point in the directional spool that can be connected to the work line via a load pressure sensing point that can be activated in a direction-dependent manner, and with at least one relief line leading from the control line via the directional spool to the drain line, in which at least one safety valve is arranged that, when a predetermined load pressure is reached - Or movement limit can be switched to a passage position, the relief line in the directional spool can be switched to passage depending on the direction and synchronously with the respectively activated load pressure sensing point.

The fact that in the known solution, the safety valve in one is arranged between the passage in the directional spool and the discharge line lying section of the relief line, the section of the relief line containing the safety valve remains depressurized until the safety valve is used for monitoring the direction of movement of the hydraulic motor assigned to it. This ensures with the known solution that different safety valves can be defined independently for each direction of movement.

The WO 02 / 090778A2 describes a control device in the manner of a valve block, consisting of at least one pressure supply and a tank or return connection as well as two useful connections and control and / or regulating valves connected between the individual connections as well as with two control lines, which at least one of the control and / or Can control valves.

The WO 2004/099657 A1 discloses another control device. Proceeding from this prior art, the object of the invention is to further improve the known control device while maintaining the advantages described above in such a way that its range of functions is increased in order to be able to achieve increased functional reliability in this way. A relevant object is achieved by a device having the features of claim 1 in its entirety.

• der jeweilige Funktionsblock als standardisiertes Modulbauteil an ein genormtes Flanschbild des Ventilblocks angeschlossen ist und je nach Einsatz Ventilelemente unterschiedlicher Ausgestaltung aufweist,
• Anschlussleitungen des jeweiligen Funktionsblocks mit korrespondierenden Anschlüssen in dem Flanschbild in fluidführender Verbindung sind,
• zwei der Anschlussleitungen Loadsensing-Leitungen sind, von denen eine an das jeweilige Ventilelement angeschlossen und die andere gesperrt oder an ein weiteres Ventilelement des Funktionsblocks angeschlossen ist, und
• die weitere Anschlussleitung des Funktionsblocks an eine der beiden Steuerleitungen des Ventilblocks angeschlossen ist, die als Leckölleitung dient.

The device according to the invention with the control device is characterized in that it consists of at least one pressure supply and a tank or return connection as well as two useful connections and control and / or regulating valves connected between the individual connections and with two control lines which control at least one of the control and / or control valves, wherein a module-like function block is connected to at least one of the control lines, and wherein

• the respective function block is connected as a standardized module component to a standardized flange pattern of the valve block and, depending on the application, has valve elements of different designs,
• Connection lines of the respective function block with corresponding connections in the flange pattern are in fluid-carrying connection,
• two of the connecting lines are load sensing lines, one of which is connected to the respective valve element and the other is blocked or connected to a further valve element of the function block, and
• the further connection line of the function block is connected to one of the two control lines of the valve block, which serves as a leak oil line.

The known pressure limiting and switch-off functions for the load signaling signal regularly only consider the section-relevant load signaling pressures A and B of the working or useful connections located in this section. With the function block solution according to the invention, it is possible to route the signal from the previous sections to this section and the signal reported to the next section (upstream and downstream of a section change valve) and to manipulate them accordingly by means of the function block. Also in the context of the increasingly demanded security requirements, this opens up additional design options for the relevant control devices to the person skilled in the art.

Due to the fact that the function block used in each case is connected to one of the control lines of the control device, a possible failure of a pressure reducing valve or a possible failure of an electro-proportional pressure control valve, which is regularly used in such control devices as control and / or control valves, can be used via the function block find, compensate, which significantly increases the functional reliability of such control devices. In this way, a modular system with regard to the functional safety of the hydraulic pilot control according to DIN EN ISO 13849 has been created for hydraulically operating machines.

Because at least one of the control lines is connected to a function block with a modular structure, depending on the design of the function block, further control and regulating tasks can be solved and the functional reliability of the overall control device can be increased. It is surprising for an average specialist in the field of hydraulic control devices that, given a suitable design of the module-like function block, he can conceptually revise existing control devices in the form of a large number of further designs, and in this way can also regularly increase the functional reliability.

It is particularly advantageous to design the function block used in each case, for example as a pressure relief valve and to control it with the control pressure of a load sensing line LP, whereas in another further preferred configuration the function block has an electromagnetically switchable directional valve which on its input side has the pressure from another load sensing - Line LS receives. Further function blocks that can be used advantageously are in Fig. 1a shown.

It is also particularly surprising for an average person skilled in the art when designing such control devices that, with the appropriate design, he can use the function block mentioned to temper the fluid volume flow within an overall hydraulic circuit. In winter or in very cold areas of application for the hydraulic control device, in order to prevent malfunctions, it is more than sensible to temper the oil volume flow.

Other advantageous feature configurations are the subject of the further subclaims.

Fig. 1, 1a, 1b

die erfindungsgemäße Steuervorrichtungslösung.

The control device according to the invention is explained in more detail below on the basis of various exemplary embodiments according to the drawing. In principle and not to scale, the type of hydraulic circuit diagrams show the

1, 1a, 1b

the control device solution according to the invention.

If connection points, lines or valves are specified in the hydraulic circuit diagrams, these are no longer explained in detail, but are the subject of the usual nomenclature in this area.

The representation after the Fig. 1 relates to a control device, in particular for the electro-hydraulic control of components of mobile machines, which are not shown here, however. The control device shown has a pressure supply connection P and a tank or return connection T and also has two useful connections A, B to which a hydraulic consumer, for example in the form of a working cylinder (not shown in more detail) or in the form of a hydraulic motor, can be connected. Furthermore, two control lines C and Z are shown, as well as load sensing lines LS, LX and LP along with the associated load sensing connections. A so-called individual pressure compensator 10 is used as control and regulating valves of the control device, which is connected upstream of the control slide 12 of a directional control valve 14, which can be designed, for example, as a proportional pressure regulating valve. Furthermore, two changeover or priority valves 16 are used, as well as two electro-proportional pressure control valves 18, which on the output side control the control slide 12 of the directional control valve 14 in its displacement position on opposite sides in each case. The control device is designed in the manner of a valve block 20 and has, at least on one of its sides, a flange pattern 22 for connecting various module-like function blocks 24, 26.

The load signal in combination with the individual pressure compensator 10 connected upstream of the control slide 12 has a decisive influence on their functional properties in the case of quantity-controlled mobile valves. If, for example, the load signal is limited to a set value with the aid of a pressure relief valve, when this value is reached, the individual pressure compensator 10 ensures that the amount of consumer continuously decreases due to its closing movement. If the load signal is not limited to a set pressure, but is completely relieved in the direction of the tank connection T, the individual pressure compensator 10 remains in its closed position. When the control slide 12 is deflected, no quantity can then flow via the individual pressure compensator 10 and thus via the slide 12 in the direction of the consumers connected to the consumer connections A, B. The function is therefore blocked by the pressure supply device P, for example in the form of a hydraulic pump in the direction of the consumer, connected to the useful connections A, B. As you can imagine, the manipulation of the load signal can be of great importance in the context of mechanical safety considerations. The individual overpressure limitation of the load signal for the consumer or utility connections A and B, which is integrated in the individual slide sections, is standard from today's perspective. In addition to any pressure limiting functions, electrically operated shut-off valves are also state of the art and, for example, in DE 42 30 183 C2 shown.

The known pressure limiting and switch-off functions for the load signal only consider the section-relevant load pressures A and B of the working or useful connections in this section. The signal from the previous sections at this section and the signal reported to the next section (upstream and downstream of the section change valve) is routed to the outside according to the solution according to the invention and can be manipulated there.

With the help of Fig. 1 shown external LP load sensing connection and associated line, it is possible to limit all previous sections with only one pressure relief valve (mechanical, electrically connectable or electro-proportional) 28 instead of up to two per section. It is a prerequisite that all consumer connections of the previous sections are limited to the same lower system pressure. Furthermore, it is possible to switch off all previous sections with only one 2/2-way valve 30. The same manipulative range of functions as in the context of the load sensing line LP can be implemented via the load sensing line LS in addition to the associated LS connection, except that the load signal of the section located at this connection is also taken into account.

Like in the Fig. 1 shown, the load sensing lines LP and / or LS, together with the associated connections, can be part of a flange diagram 22 of the valve block 20 for the control device or can be implemented in the context of conventional threaded connections. According to the representation according to the Fig. 1 the function block 24 the pressure relief valve 28 to be connected and the other function block 26 the directional control valve 30. The connection lines LS, Z and LP shown for the function blocks 24, 26 are in fluid connection with the corresponding connections LS, Z and LP in the flange diagram 22 for a functionally reliable use To connect. In the relevant embodiment, the control line Z is optional and, as in the illustration according to FIG Fig. 1 shown, be designed as an internal leakage oil line Z or open into the tank line T. Depending on the machine concept, the connections LA, LB and LR ( Fig. 1b ) are also brought out. A correspondingly modified drawing is in the Fig. 1b shown, the otherwise the embodiment of the Fig. 1 corresponds, the function blocks 24, 26 not being shown further here for the sake of simplicity.

Like further the Fig. 1a shows, other function blocks (framed in dashed lines) with their valve installation components, as they correspond to the usual hydraulic circuit diagrams, can be connected to overall control devices, as exemplified in the Fig. 1 and 1b are shown, as set out above, in order to achieve modified functions for the control device and to increase the modularity of the overall concept accordingly. Are looking towards the Fig. 1a seen on the left side, individual modules are shown as functional components and on the opposite right side combinations of these modules consisting of several valve function elements in a function block to be connected. Additional logics with or without other modules can also be implemented for the load sensing lines LA, LB and LR (cf. Fig. 1b ).

With the above-mentioned functional blocks according to the invention, it is also possible to implement a concept with regard to the functional safety of the pilot pressure of the hydraulically pilot-operated main spool 12 of the directional control valves 14 previously shown.

The in the Fig. 2 , 3a , 3b , 4a , 4b and 5 Embodiments of the control device shown, just like the following description thereof, are not the subject of the present patent application.

It is shown in the prior art to use a hydraulic auxiliary force in the case of hydraulically pilot-controlled directional valves 14 so that the control element is moved regularly into the desired position in the form of the control slide 12. The assistant or pilot pressure can be applied separately from the outside or via an internal control / regulation to the opposite end faces of the control slide 12. The usual maximum pressures are between 15 and 25 bar. In order to ensure a constant quality of control or regulation, due to the dynamic pressure profiles in mobile hydraulics, care must be taken that the electro-proportional control valves receive a defined and constant inlet pressure. For this reason, either the pump pressure is reduced to a defined value independently of the current working pressure via an internal pressure reducing valve 32, or an external feed pump (not shown) is used. In most cases, the pilot control circuits are designed for this low pressure level in terms of strength.

If one now looks at the possible errors in this pilot control circuit, it will be found that both the pressure reducing valve 32 can fail and also the individual electro-proportional control valves 18 for the individual control spool sides. If, for example, the pressure reducing valve 32 is stuck, the high pressure side is connected to the low pressure side. The potential risk is very high. If, on the other hand, a control valve 18 is stuck in the control position, then a pilot slide side would be permanently subjected to a pilot pressure. The result would be an uncontrollable machine function. In this case, if you are unable to interrupt the low-pressure supply, emergency operation using the hand lever is also no longer ensured. Today's primary measures in the prior art include certain design principles for the individual components. Since contamination is still the most common cause of breakdowns today, protective screens or filter devices 34, as exemplified in the Fig. 2 are shown, arranged in the fluid guide direction upstream of the pressure reducing valve 32 and optionally upstream of the control valves 18 also to the other primary protective mechanisms. Additional pressure relief valves (not shown) can be used as secondary measures.

In order to create a cost-effective alternative to the respective pressure relief valve as a secondary measure, a further function block 36 was designed for the design of the control device shown as valve block 20 created. A fundamental disadvantage of pressure relief valves is that the function is not necessarily recognizable to the machine operator. That is, in order to really be able to detect the response of the pressure limiting valve and thus the faulty function of the pressure reducing valve, a pressure switch or pressure sensor would also be required in addition to a pressure limiting valve. This causes not inconsiderable additional costs.

In order to avoid these additional costs, instead of the known pressure relief valve in the control device according to the Fig. 2 a safety device against overpressure is used within the function block 36, which in the present exemplary embodiment according to FIG Fig. 2 is designed as a rupture disc 38 of conventional design. If the permissible pressure upstream of the control valves 18 is exceeded, the rupture disk 38 is destroyed and the pressure upstream of the control valves 18, in particular via the control line C, is completely reduced using an inlet nozzle 40 in front of the pressure reducing valve 32. A control of the valve spool 12 of the directional control valve 14 and thus an actuation of the consumers via the control valves 18 is then no longer possible. The machine connected to the control device can then still be operated via a conventional hand lever actuation (not shown) and possibly brought out of a danger area.

With this device, it is thus possible to recognize the fault immediately without electronics, and the machine can still be brought into a "safe state" with the aid of the hand lever actuation. The rupture disk 38 can be integrated in the context of a functional block 36 both in the flange or connection plate 22 and also directly in an end plate of the valve block 20 of the control device. In continuation of this idea and in order to obtain an overall modular system with regard to the functional safety of a hydraulic pilot control according to DIN EN ISO 13849 for machines, according to the Presentation of solutions according to Fig. 3a , 3b on the connection or flange plate 22 of the valve block 20 defines a predefinable flange pattern C ', C and Z, on which the pressure between the pressure reducing valve 32 and the two pressure control valves 18 can be tapped. Furthermore, there is a hydraulic connection C ′, C, at which the pressure, viewed in the direction of fluid flow, is present behind the pressure reducing valve 32.

With the help of small adaptive valve units in the form of further module-like function blocks 42, 44, 46, 48 and 50, different safety devices and thus different safety levels can now be implemented quickly and at the same time the cost-intensive variance regarding additional connection and / or end plates is limited. In order to compensate for a failure of the pressure reducing valve 32, an externally connected function block 42 would again be suitable, which in turn has the rupture disk 38 as a safety device against pressure. Another possibility would be given by the function block 44, which has a pressure relief valve 52.

In order to compensate for a failure of the electro-proportional pressure control valves 18, a manually operable shut-off unit 54 can be connected via the flange pattern 22 in the context of a connectable function block 46. A further possibility is to connect an electrically actuable 2/2-way valve 56 with a relief nozzle 58 and optional pressure monitoring 60 on the secondary side in the function block 48. There is also the possibility of also monitoring the relevant 2/2-way valve from its switching position. A further comparable possibility exists through the use of an electrically actuable 3/2-way valve 62, which in turn can optionally be monitored for the switching position and also has an optional pressure monitor 60 on the secondary side. The relevant unit can be connected to the flange pattern 22 via the function block 50, as already shown. As a concluding possibility, it will also be shown via function block 64 to monitor the pressure immediately after the pressure reducing valve 32. Furthermore, it remains to be stated that there is basically the possibility of using all of the above-mentioned functional blocks with their exchangeable contents together in a control device or to make a combinatorial selection with regard to the respective security functionality presented.

Also the Fig. 4a , 4b in turn relate to a hydraulic LS control block in the manner of a control device with which individual hydraulic consumers can be controlled via integrated valve arrangements 10, 14, 16 and 18 as a control and regulating valve assembly, which in turn can be connected to the useful connections A and B. The hydraulic energy is in turn made available via a pressure supply device P, for which purpose both variable and constant pumps can be used.

With certain mobile machines such as Loading cranes, mobile cranes, concrete pumps etc. can occur if there is no hydraulic actuation for a long time. The control device can cool down to ambient temperature, while the pressure medium in the overall hydraulic circuit can have a significantly higher temperature due to the actuation of delimited subsystems. If a control slide 12 of one of the directional control valves 14 is now actuated, the warm oil flows into the control slide 12. Since the control slide 12 and the valve housing surrounding it can expand differently due to the material, shape and flow around them under the influence of temperature, the respective control or valve slide 12 may jam in the associated housing of the directional control valve 14, particularly in winter.

In the solution according to the Fig. 4a , 4b The temperature control function should only take place if this is also necessary, ie if no hydraulic consumer is actuated. So only then be tempered when a defined volume flow through the valve block 20 in the direction of the tank connection T. However, if a hydraulic consumer, which is connected to the utility connection A, B, is actuated, the temperature should not be increased in order not to generate unnecessary power loss. Nor should there be any intervention in the pressure-reduced pilot pressure supply for the hydraulic pilot control units.

In the case of frequently used LS systems in mobile hydraulics, the variable pump maintains a previously defined and set differential pressure, for example 25 bar, in neutral circulation, i.e. when no hydraulic consumers are actuated. With constant pumps there is also a certain low pressure at the control block connection in the form of the pressure supply connection P, which is dependent on the volume flow and corresponds to the differential pressure of the neutral circulation circuit (usually> 5 bar). That is, in both cases, a low pressure can be used to allow a defined volume flow to flow through the control or valve block 20 with the aid of a simple orifice 66 for the purpose of tempering.

However, it is important that the volume flow can run through all slide sections as shown in the Fig. 4a , 4b . If both connections P and T are in a valve module in the form of the valve block 20, this is achieved through an additional channel 68. This channel 68 is not earmarked and can basically be used for various tasks in the entire modular valve system. In the present case, it guides the volume flow from the connection plate or flange plate 22 through all sections into the end plate, where the volume flow mentioned specifically ends in the T-channel. The T-channels have the basic advantage of being very large in terms of cross-section, so that they can also give off a lot of heat due to the large area they create.

This solution therefore has the advantage that it would still work if the sections were separated from the actual main hydraulic circuit (not shown) via a P-channel shut-off or point switching for safety reasons. In this case, pressure medium from P can still be fed through channel 68 into the end plate and from there into the T channels. If such a P shut-off does not exist, it would be even more effective if one were to in accordance with the circuit diagram Fig. 5 go via the P-channel into the end plate, then via the nozzle or orifice 66 into the T-channels and back again to the connection or flange plate 22. This would then have the advantage that three large channels could be used simultaneously for heat dissipation.

In neutral circulation, a volume flow defined via the orifice 66 and the open closing element 70 of a so-called cartridge valve 72 is now fed into the additional channel 68, passed through all sections into the end plate and there specifically into the T channels and thus back to the connection plate 22 and to the tank or return port T. The relevant transition point 74 is in the direction of viewing Fig. 4 seen on the right. If a consumer is now actuated, the load reporting line (LS chain) reports the consumer pressure into the connection or flange plate 22 and at the same time onto the closing element 70 of the valve 72. This interrupts the temperature control function through the additional channel 68 and ensures that no unnecessary ones Power losses arise during consumer confirmation.

The logic arrangement consisting of the diaphragm 66 and the closing element 70 of the valve 72 can, due to the additional channel 68, both in the connection or flange plate 22 ( Fig. 4a ) as well as in the end plate ( Fig. 5 ) are arranged in the valve block 20. In the first case, the additional channel 68 is used for the volume flow guidance to the end plate in the form of the valve block 20; in the second case, the highest load signal of the LS chain is sent back to the end plate on the locking element via this channel 68 70 of the valve 72 reported. As already mentioned, this arrangement in the end plate has the advantage that both the large T channels and the large pressure supply channel P can be used for the temperature control function, the T and P connections then both in the connection or flange plate 22 are arranged. In the case of a P-channel switch-off, a priority switch or a switch, this arrangement would no longer work. The orifice 66 and the closing element 70 of the valve 72 in turn form a common unit in the form of a function block 76 which can be connected in a modular manner. The relevant function block 76 can in turn be integrated directly in the control or valve block 20, as well as according to the illustration in FIG Fig. 4a can be adapted to the control or valve block 20 with the aid of a suitable flange pattern via the connection or flange plate 22. According to a further embodiment, not shown in detail, the function block 76 can also be located together with the pressure reducing valve 32 together with the filter device 34 on the opposite side, that is to say in the direction of view of the Fig. 4b seen on the right, can be connected to the valve block 20 by means of a suitable flange or connection plate 22.

Claims (4)

1. Device consisting of a control device in the form of a valve block (20), particularly for hydraulic control of components of mobile work machinery, and a function block (24, 26), the control device consisting of at least one pressure supply (P) and one tank or return connection (T) and two utility connections (A, B) and control and/or regulating valves (10, 14, 16, 18) connected between the individual connections (P, T, A, B), and with two control lines (C, Z), which can control at least one of the control and/or regulating valves, wherein the function block (24, 26) with a modular design is connected to at least one of the control lines (C, Z), and wherein

   - the respective function block is connected as a standardised modular component to a standardised flange interface (22) of the valve block (20) and comprises valve elements of different designs depending on usage,

   - connection lines (LS, LP and Z) for the respective function block are connected in a fluid-conveying manner with corresponding connections (LS, LP and Z) in the flange interface (22),

   - two of the connection lines (LS, LP) are load-sensing lines, one of which is connected to the respective valve element and the other is blocked or connected to another valve element of the function block, and

   - the other connection line (Z) of the function block is connected to one of the two control lines (Z) of the valve block (20), which acts as an overflow oil line.
2. Device according to claim 1, characterised in that the valve elements are designed in the form of a pressure-limiting valve (28) or a preferably electromagnetically actuatable throttle valve, preferably a 2/2 throttle valve (30) or an orifice plate.
3. Device according to either claim 1 or claim 2, characterised in that one of the control and/or regulating valves is a pressure compensator, especially an individual pressure compensator (10).
4. Device according to any one of the preceding claims, characterised in that one of the control and/or regulating valves is a multi-way slide valve (14), to which the utility connections (A, B) are connected on the outlet side in a fluid-conveying manner.

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