Valve device for a self-propelled work machine including a hydraulic consumer

Abstract

A valve device for a self-propelled work machine (1) having hydraulic consumers (47, 50), the valve device comprising at least one direction control valve (30, 31, 55, 64) connected to the pressure lines (P1, P2, 56, 65) and the work lines (A1, A2, 52, 54) of the hydraulic consumers (47, 50); a hydraulic control line (C, 58, 63) designed to move at least one direction control valve (30, 31, 55, 64) to a first position; a pilot valve (32, 59) connected to the hydraulic control line (C, 58, 63); a pressure supply line (Pa, 66); and a pressure reduction line (T, 62), the pilot valve (32, 59) being designed to selectively connect the hydraulic control line (C, 58, 63) to the pressure supply line (Pa, 66) and the pressure reduction line (T, 62).

Description

Technical Field

[0001] The present invention relates to a valve device, the use of such a valve device, a self-propelled work machine having the features of the preamble of claim 15, and a method for minimizing hydraulic oil loss in a self-propelled work machine.

Background Art

[0002] Self-propelled machines having a hydraulic system, in particular self-propelled hydraulic construction machines, are used in various ways at construction sites for demolition and dismantling work. Such self-propelled machines are also used in civil engineering and forestry. Examples of self-propelled machines include cranes, excavators, as well as material handlers, forestry machines, etc. In the demolition sector, so-called "long front" excavators or demolition excavators are used. The long booms and arms make good tools for using hydraulic attachments for each purpose of the self-propelled hydraulic construction machine, even at heights of over 20 m. When operating a self-propelled hydraulic construction machine, the hydraulic hoses forming the hydraulic system of the attachment are exposed to the aging process or external influences due to the weather, which can cause damage to the hydraulic hoses. However, another completely unexpected cause of damage is the external mechanical influence on the hydraulic hoses caused by work in areas that cannot be fully visually inspected. The operator of the excavator cannot see all parts of the self-propelled hydraulic construction machine during operation, which means that the hydraulic hoses can be damaged, for example, by catching on sharp objects at the construction site, or being punctured, cut, or broken. On the one hand, due to the inevitable aging process, and on the other hand, due to unforeseen external influences, oil leakage may occur in the hydraulic hoses during the normal operation of the construction machine. In particular, from the disclosed document EP2547912, it is known to interrupt the lines of the hydraulic system of the attachment so that the attachment does not cause any uncontrolled movement, remains fixed in position, and does not pose any safety risk at the construction site due to pipe rupture. However, the hydraulic system is only interrupted on the attachment side. That is a problem. Because the long booms and arms of the self-propelled hydraulic working machine also require long hydraulic lines that have to run from the end of the arm to the attachment, and thus in the case of oil leakage, more than 400 liters of oil can often reach the ground at the construction site in less than 30 seconds. The loss of oil, which is often extremely hot, means not only additional costs for replacing the lost oil, but also significant environmental pollution at the construction site and often a great danger to people.

[0003] The same applies to the use of forestry harvesters, some of which have grapples on long booms for gripping the main stem of the tree, which, in addition to a hydraulic unit for the grapple, also include a hydraulic motor for rotating the grapple. SUMMARY OF THE INVENTION

[0004] The present invention is based on the problem of providing a reliable and relatively simply constructed valve device, an environmentally friendly hydraulic working machine, a method for minimizing hydraulic oil loss in a self-propelled working machine in the case of a leak in the working line, and the corresponding use of the valve device.

[0005] This problem is solved by a valve device having the features of claim 1, a use having the features of claim 14, a working machine having the features of claim 15, and a method for minimizing hydraulic oil loss in a self-propelled working machine having the features of claim 18.

[0006] Accordingly, there is provided a valve device having the following for a self-propelled working machine having a hydraulic consumer: - at least one directional control valve connected to the pressure line and the working line of the hydraulic consumer, - a hydraulic control line designed to move at least one directional control valve to a first position, - a pilot valve connected to the hydraulic control line, - a pressure supply line, and - a pressure reduction (bleed-off) line, provided that the pilot valve is designed to selectively connect the hydraulic control line to the pressure supply line and the pressure reduction (bleed-off) line.

[0007] The valve device makes it possible to safely move the directional control valve to a closed position in the case of a leak in the working line, substantially preventing oil leakage from the leak site.

[0008] Preferably, when the first position of at least one direction control valve is the closed position, the flow is blocked in both directions. The pilot valve can ensure that the direction control valve remains in the blocked position.

[0009] Preferably, at least one direction control valve is spring-biased towards the first position, and at least one direction control valve has two pilot control lines connected to the working chamber on the side opposite to the spring. The first pilot control line is connected to the pressure line, and the second pilot control line is connected to the working line. The pilot control lines enable the direction control valve to move to the open position when the hydraulic consumer is activated. It is obvious to those skilled in the art that the pilot control line or the working chamber can also be the active surface that moves the direction control valve when pressure is applied.

[0010] The pilot valve can be a 3 / 2 or 4 / 2 directional valve.

[0011] Preferably, the pilot valve is electrically operable and, in the non-operating position, connects the pressure supply line to the hydraulic control line, and in the operating position, connects the hydraulic control line to the pressure reduction line. However, it is also conceivable to operate the pilot valve in another way, especially wirelessly.

[0012] Preferably, the pilot valve can be electrically operated to the operating position but can be deactivated by an emergency stop switch. The emergency stop switch can be arranged in the working chamber of the working machine so that it can be manually operated.

[0013] If the hydraulic consumer has two working lines, for example, a double-acting hydraulic cylinder, the valve device preferably includes a first direction control valve and a second direction control valve, which are each connected to the pressure line and the working line of a common hydraulic consumer, and a plurality of hydraulic control lines are connected to each other such that when they are pressurized starting from a pilot valve, they guide the two-way control valve to a closed position. The two-way control valve preferably has the above-described features. By connecting the control lines, the two-way control valve is actuated by a single pilot valve. It is also conceivable to use two pilot valves. The pilot valves can then be wirelessly communicated with each other or electrically connected by wireless or other means.

[0014] In one embodiment, the valve device includes a shuttle valve having a first blockable inlet, a second blockable inlet, and an outlet. The first blockable inlet of the shuttle valve is connected to the first pressure line of the first direction control valve, the second blockable inlet of the shuttle valve is connected to the second pressure line of the second direction control valve, the outlet of the shuttle valve is connected to the pressure supply line, and the shuttle valve is designed such that the pressure line having the highest pressure among the first pressure line and the second pressure line can be connected to the pressure supply line.

[0015] However, it is also possible to connect the pressure supply line to the pressure line and the working line via branch(es), the branch(es) being parallel and each having a non-return valve, and the non-return valve being arranged such that the highest pressure among the pressures present in the pressure line and the working line is guided to the pressure supply line.

[0016] The pressure reduction line can be a tank line (return line) that can be connected to the tank.

[0017] However, the pressure reduction line is connected to the pressure line and the working line via the branch part(s), the branch part(s) are present in parallel, each has a non-return valve, and the non-return valve opens to one of the pressure line and the working line having the lowest pressure when pressure is applied to the pressure reduction line, thereby reducing the pressure. In this embodiment, a return line is not required, which can be advantageous if the valve device is used at a position far from the upper structure.

[0018] The first direction control valve and / or the second direction control valve can be a 2 / 2-way valve, whereby the flow of hydraulic oil in both directions is blocked in the blocked position and the flow of hydraulic oil in both directions is possible in the passing position.

[0019] Furthermore, the use of the above-described valve device in the working line of a hydraulic consumer in a self-propelled work machine is provided to close the working line when a leakage of hydraulic oil occurs in the working line and prevent a large amount of hydraulic oil from leaking from the leakage point.

[0020] Furthermore, a self-propelled work machine having a lower structure, an upper structure, a boom assembly, and a hydraulic system, wherein the hydraulic system includes a hydraulic pump, a volume control valve, a hydraulic consumer, and at least two hydraulic lines, and the volume control valve is designed to adjust the oil flow through at least one of the hydraulic lines to control the hydraulic consumer, is provided. At least one of the hydraulic lines has a direction control valve, and the direction control valve is designed to close the hydraulic line in case of a leakage of the hydraulic line. The boom assembly can have two or more links, particularly a boom and an arm. The direction control valve can be, for example, a slide valve, a seat valve, a plate valve, etc.

[0021] Preferably, the direction control valve is arranged between the volume control valve and the hydraulic consumer. This is because hydraulic oil may leak from the leakage point even when the volume control valve is closed. For example, this is the case when the suction valve is used in a bypass that bridges the volume control valve to prevent cavitation.

[0022] Preferably, the self-propelled work machine has a valve device as described above, and the direction control valve is part of the valve device.

[0023] In one embodiment, the hydraulic consumer is a hydraulic cylinder, which is particularly double-acting. In this case, as described above, there is one direction control valve in each of the hydraulic lines. It is also conceivable to provide more than one direction control valve or more than one valve device to protect the hydraulic lines in different ways. Furthermore, the plurality of control sections of the self-propelled work machine can each have such a valve device. That is, a number of hydraulic lines to different hydraulic consumers can be protected as required.

[0024] Furthermore, a method for minimizing hydraulic oil loss in the above self-propelled work machine when hydraulic oil leaks in the work line is provided, the method including the following consecutive steps: (a) If a leak occurs in the hydraulic line between the hydraulic consumer and the direction control valve, move the direction control valve to the closed position, thereby closing the hydraulic line. (b) Ensure that the locking in the closed position is maintained until the leak is rectified. (c) After the leak is rectified, return the direction control valve and / or the valve device to the initial state or initial position before the leak.

[0025] In contrast to other valves or valve devices that close the hydraulic line, this method allows the self-propelled work machine to be operated and kept moving, except for the control section assigned to the leakage line. According to this method, it is ensured or can be ensured that the closed position is maintained until the leakage is rectified and the work line is repaired, and the hydraulic oil can be reliably prevented from leaking from the work line. Valves without this option are not suitable as emergency stop devices to prevent a large amount of hydraulic oil from leaking from the leakage part. The direction control valve or valve device is preferably returned to the state before leakage, and the line is closed without tools and without replacing or renewing parts / components. It is particularly preferred that the initial state is brought about automatically, for example, even after release by the operator. Such release can include input to the operating unit, actuation of a switch, etc.

[0026] Further possible embodiments of the valve device, drive machine, and method are described below.

[0027] There is provided a valve device for a work machine, in particular a construction machine having a hydraulic tool, having the following: - A first direction control valve connected to the first pressure line and the first work line, in particular a first 2 / 2-way valve, - A second direction control valve connected to the second pressure line and the second work line, in particular a second 2 / 2-way valve, - A 4 / 2-way valve connected to the inlet pressure line, the outlet line, the first control line, and the second control line, - A shuttle valve having a first blockable inflow part, a second blockable inflow part, and an outflow part, - The 4 / 2-way valve is electrically operable and, in the non-operating position, connects the inlet pressure line to the first control line and, in the operating position, connects the first control line to the outlet line, Both the first direction control valve and, essentially simultaneously, the second direction control valve can be closed when the 4 / 2-way valve is in its deactivated position. The deactivated position is preferably energy-deprived. The transition to the deactivated position can be effected by means of an emergency stop switch or by means of an electrical interruption.

[0028] The second control line is permanently blocked and is preferably connected to the inlet pressure line when the 4 / 2-way valve is in its activated position.

[0029] Furthermore, if the first blockable inlet of the shuttle valve is connected to the first pressure line, the second blockable inlet of the shuttle valve is connected to the second pressure line, and the outlet of the shuttle valve is connected to the inlet pressure line, then both 2 / 2-way valves are closed in the deactivated position of the 4 / 2-way valve by the pressure of the higher-pressure pressure line. For this purpose, the control line is connected to the first 2 / 2-way valve and the second 2 / 2-way valve, and it is advantageous for the control line to advance these valves to the closed position when the control line is pressurized.

[0030] The emergency stop function can be achieved particularly easily and reliably if the 4 / 2-way valve is electrically actuated in the working position and can be deactivated by means of an emergency stop switch. The emergency stop switch is particularly advantageously arranged in the working chamber of the machine so that it can be operated manually. The emergency stop function can be provided in the event of a leak in the working line.

[0031] In a general working machine, at least two hydraulic lines are each assigned to at least one direction control valve, in particular a 2 / 2-way control valve, which is designed to close the hydraulic line in the event of an emergency, whereby at least one direction control valve for each of the two hydraulic lines is arranged in the region of the substructure of the hydraulic line between the valve and the hydraulic tool or in the region of the boom hydraulic line, so that leakage of hydraulic oil from the upstream hydraulic system of the working machine can generally be prevented in the event of a leak in the boom region hydraulic line.

[0032] The directional control valve is preferably hydraulically pilot-controlled. In particular, they have an opening pressure within the normal tolerance of 1 bar to 10 bar, in particular 1.5 bar to 5 bar, particularly preferably about 2 bar. This keeps the pressure loss relatively low. The directional control valve is also preferably designed for a working pressure of 200 bar to 450 bar, preferably 300 bar to 450 bar, in particular 350 bar to 420 bar. The pilot valve is preferably designed for a working pressure up to 500 bar. Finally, the valve arrangement is preferably designed for a flow rate (volumetric flow) of 50 litres per minute (l / min) to 2500 l / min, in particular 600 l / min to 1500 l / min, particularly preferably 700 l / min to 1350 l / min.

[0033] The valve arrangement preferably has a modular design such that, regardless of the particular shape of the valve arrangement, for example, one directional control valve can be mounted on one side of the boom and the other directional control valve on the other side of the boom.

[0034] A particularly advantageous embodiment is one in which the directional control valves of the valve arrangement can be directly connected to the shut-off valve or rapid change connection of the working machine or can even replace them. Ball valves are often mounted in the area of the boom of an excavator that has to be closed in order to change the attachment tool. The valve arrangement according to the invention can be mounted in place of these ball valves, so that in addition to improved operating safety there are additional advantages in terms of automatic closing of the valves when the excavator is switched off and saving of working time.

[0035] The directional control valve can be closed by actuating an emergency stop switch and reopened by actuating the emergency stop switch again once the leak has been rectified. However, it is also possible for the directional control valve to be automatically controlled by a sensor that detects a pressure drop or to be completely automatically closed hydraulically in the event of a pressure drop.

[0036] If at least two hydraulic lines of a working machine are located in a protected area above the boom, formed by ducts or pressure medium pipes, and each directional control valve is arranged in this protected area, the possibility of damage to the hydraulic line on the pressure side of the valve device and to the valve device itself is particularly reduced during demolition work. Preferably, each directional control valve or 2 / 2-way valve is integrated into a valve block, which can be flange-mounted, for example, to a duct.

[0037] Preferably, at least two hydraulic lines for directly supplying a tool are each attached to the tool at a first attachment point and to the boom at a second attachment point, forming a flexible hose vent between the two attachment points, and at least one directional control valve or 2 / 2-way valve is arranged outside the flexible hose vent in the area of the boom. The two directional control valves are preferably hydraulically and / or electrically connected to each other.

[0038] If the second attachment point of each hose vent is located at the respectively assigned directional control valve, no additional connection parts or passive outlet safety devices are required in this area.

[0039] Preferably, the hydraulic tool is an excavation tool, a demolition shear, a forestry tool or a civil engineering tool. According to these tools and their areas of use, there is a particularly high risk of line breakage due to damage during operation. The safety device described in this context is particularly advantageous if the lower structure is self-propelled.

[0040] An emergency that leads to the closing of the 2 / 2-way valve is advantageously the rupture of at least one hose vent, particularly close to the tool mounted on the arm.

[0041] Preferably, such a working machine has a valve device with the above-mentioned features.

[0042] A method for protecting the above-mentioned working machine, including the following continuous steps, is also proposed: (a) If a leak occurs in at least one of the hydraulic lines between the hydraulic tool and the valve, move at least one direction control valve or 2 / 2-way valve to the closed position (non-operating position), thereby closing at least two hydraulic lines. (b) After the leak has been rectified, move at least one direction control valve or 2 / 2-way control valve to the initial position.

[0043] This means that if a hydraulic line is damaged, even if the hydraulic pump of the working machine continues to pump oil, the amount of oil leaking can be effectively limited. Thus, damage to the hydraulic pump due to idling can be prevented. This method can also protect workers and save hydraulic oil (resource conservation).

[0044] In particular, the hydraulic tool can include a double-acting hydraulic cylinder, and the two hydraulic lines connected to the double-acting hydraulic cylinder can be closed in step (b).

[0045] When using the above valve device in a working machine to prevent uncontrolled oil leakage from the hose break point in the case of hose breakage in the hose vent area of two working lines, a particularly high level of reliability is achieved with simple operation in an emergency.

[0046] Furthermore, the self-propelled hydraulic working machine can include an upper structure, a lower structure, a boom assembly (preferably having a boom and an intermediate boom), an arm, an attachment connected to the arm, and a hydraulic system for moving the boom assembly and the attachment. The hydraulic system has at least one pump and one additional valve block, and the additional valve block is designed to regulate the oil flow in at least two hydraulic lines that connect the attachment to the pump for controlling the attachment. At least one emergency stop valve is assigned to each of the hydraulic lines, which is designed to close the hydraulic line in an emergency, and at least one emergency stop valve is arranged in the upper structure on the flow side of the additional valve block away from the pump and / or in the area of the boom assembly of the hydraulic line. The emergency stop valve can be represented by the above valve device. The emergency stop valve can also include a closing device such as a slide valve.

[0047] The emergency stop valve can close the hydraulic line in case of leakage, thereby preventing a large amount of hydraulic oil from leaking. It is particularly easy to operate the emergency stop valve in the upper structure area. The use of the emergency stop valve in the area of the arm is advantageous. This is because it is very advantageous in case of leakage in the area between the boom assembly and the attachment.

[0048] Preferably, at least two hydraulic lines are located in the protected area above the arm or are formed by conduits, and each emergency stop valve is located in this protected area. The protected area means that the hydraulic line is a rigid pipe made especially of metal and is protected from external influences. These protected areas must be distinguished from areas of hydraulic lines having flexible hoses that can be easily torn or damaged.

[0049] The hydraulic line is attached to the attachment at the first attachment point and to the arm at the second attachment point, forming a flexible hose vent between the two attachment points. Preferably, at least one emergency stop valve is arranged outside the flexible hose vent in the area of the arm. During normal operation of the self-propelled hydraulic working machine, oil leakage often occurs at the flexible hose vent. This is because the flexible hose vent, by its nature, is prone to being pierced at multiple points, for example, at a construction site. However, the hose vent is essential for the use of the working machine. This is because without the hose vent, the boom assembly and the attachment cannot be moved significantly. By closing the emergency stop valve, and thus the hydraulic line and the hydraulic system, it is possible to prevent oil from leaking in case of an oil leak.

[0050] Preferably, the emergency stop valve is an electronically controlled solenoid valve, which is particularly cost - advantageous. The emergency stop valve can be a two - way valve as described above, and the hydraulic system preferably includes at least one return line. The at least one return line connects the emergency stop valve to the hydraulic oil tank, from where the hydraulic system is supplied by a pump. In this case, there is no need to communicate with an additional valve block. This is because the flow of hydraulic oil through the hydraulic line in the area of the additional valve block does not need to be interrupted.

[0051] In a further preferred embodiment, the self - propelled hydraulic working machine includes an emergency stop actuator that communicates with the emergency stop valve and / or optionally additionally with an additional valve block, and is configured to close the emergency stop valve when actuated.

[0052] Preferably, the emergency stop actuator is arranged in the driver's cab of the self - propelled hydraulic working machine. If the driver of the self - propelled hydraulic working machine detects a leak, he can actuate the emergency stop actuator, thereby preventing the oil from continuing to leak at the break point.

[0053] Preferably, at least one sensor is assigned to at least two hydraulic lines, which is configured to detect leaks in at least two hydraulic lines, and at least one sensor communicates with an emergency stop valve and / or an additional valve block. In this case, the emergency stop valve can be automatically closed in case of pressure drop and leakage in the hydraulic line.

[0054] In a preferred embodiment, the self-propelled hydraulic working machine is a long-boom excavator having a reach height in the range of 15 m to 90 m and in particular a weight class of 25 t to 400 t. However, it can also be a mini-excavator up to about 10 t or a small excavator up to about 18 t.

[0055] Furthermore, a method for controlling a self-propelled hydraulic working machine having an upper structure, a lower structure, and a boom assembly, wherein the boom assembly has an arm, the self-propelled hydraulic working machine further has an attachment connected to the arm, and a hydraulic system for moving the boom assembly and the attachment, the hydraulic system including at least one pump and one valve block, in particular an additional valve block, and at least two hydraulic lines connecting the attachment to the pump, and the valve block or the additional valve block being connected to at least two hydraulic lines, is provided. This method includes the following successive steps: (a) Detecting a leak in one of the hydraulic lines between the attachment and the valve block or the additional valve block, (b) Switching on at least one emergency stop valve, thereby closing at least two hydraulic lines, provided that the emergency stop valve is arranged in the upper structure on the flow side of the valve block or the additional valve block remote from the pump in at least one of the at least two hydraulic lines, and / or in the region of the boom assembly.

[0056] Preferably, at least one emergency stop valve is a two-way valve, the hydraulic system includes at least one return line, and the following step is provided in step (b) of the method: - Connect the hydraulic line to the return line by means of an emergency stop valve, the return line being connected to the hydraulic oil tank, and the hydraulic system being supplied from the hydraulic oil tank by a pump.

[0057] Preferably, the method includes the following step between steps (a) and (b): - Actuate a valve block or an additional valve block to close at least two hydraulic lines, provided that step (b) is thereby carried out with a predetermined time delay.

[0058] Preferably, the method includes detection by visual inspection by an operator or by sensors arranged in the hydraulic lines.

[0059] Preferably, the self-propelled hydraulic working machine includes an emergency stop actuator that communicates with the emergency stop valve and / or the valve block or an additional valve block, and the method according to step (a) includes the following steps: - Manually actuate the emergency stop actuator by the operator.

[0060] The self-propelled hydraulic working machine can be designed as described above.

Brief Description of the Drawings

[0061] Preferred embodiments of the present invention are described in more detail below with reference to the drawings.

[0062]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0063] FIG. 1 shows a self-propelled work machine 1, in particular a hydraulic construction machine, as a preferred embodiment of a long-arm boom excavator having a lower structure 2, the lower structure 2 being connected to an upper structure 4 via a rotary mechanism 3 that can rotate about a rotation axis S. The rotary mechanism 3 enables a controlled rotational movement between the upper structure 4 and the lower structure 2 about the rotation axis S. Generally, a wheeled excavator and a crawler excavator can be distinguished. In the case of a wheeled excavator, the lower structure 2 can have tires on the chassis. The wheeled excavator is only used in weight classes up to 25 t. On the other hand, the crawler excavator can have endless tracks and is used in all weight classes. The wheeled and crawler excavators should be distinguished from other types of excavators, such as floating excavators, as self-propelled land vehicles. In the preferred embodiment, the long-arm excavator 1 is realized as a crawler excavator, which is in the general weight class of 25 t to 400 t for demolition work. The upper structure 4 has a cab 5 at its end in the travel direction (forward direction) F and a counterweight 6 at the end opposite the cab 5. FIGS. 1 and 2 show a boom assembly 7 consisting of three parts, which is attached to the upper structure 4 adjacent to or behind the cab 5. The boom assembly 7 has three links 8, 9, 10 arranged connected to each other. The first member 8 is called the boom, the second member 9 is called the intermediate boom, and the third member furthest from the upper structure is called the arm 10, and two consecutive members are pivotally attached to each other by bolts. The boom assembly 7 further includes a boom cylinder 11 that can move the first link 8 of the boom assembly and an intermediate boom cylinder 12 that can move the second link 9 of the boom assembly 7. Further, an arm cylinder 22 is provided that can be driven to move the arm 10. An attachment 14 is attached to the free end of the arm 10, and an arm head bolt 13 passes through it. This connection can preferably be made by a quick coupler. The attachment 14 and the quick coupler can also be pivoted about a pivot axis defined by the arm head bolt 13.In this embodiment, the attachment 14 is a gripping tool, but any hydraulic attachment such as a shearing machine can be used.

[0064] The self-propelled hydraulic working machine 1 includes a hydraulic system that drives the boom cylinder 11, the intermediate boom cylinder 12, and the arm cylinder 22 with hydraulic oil. The flow of the hydraulic oil and the related movements are controlled and monitored by a main valve block of a hydraulic system (not shown) located in the upper structure 4. The main valve block includes a valve that adjusts the supply amount of the hydraulic oil to one of the hydraulic cylinders. Further, the main valve block has a role of controlling the hydraulic rotation drive of the rotation mechanism 3 and the hydraulic travel drive for the endless track of the lower structure 2. An additional valve block 15, a hydraulic oil tank 16, and a hydraulic pump 17 also belong to the hydraulic system and are provided in the upper structure 4. The hydraulic pump 17 supplies the hydraulic oil of the hydraulic system and is connected to the main valve block and the additional valve block 15 via a hydraulic connection. If the performance of one pump is not sufficient for the required application, or if the system is designed redundantly, multiple pumps can be used in the hydraulic system. The additional valve block 15 controls and adjusts the flow of the hydraulic oil to the attachment 14. The hydraulic line 18 leads from the additional valve block 15 to the attachment 14. Although FIG. 1 shows only one hydraulic line 18, depending on the type of attachment and the working machine used, multiple or at least two hydraulic lines 18 can exist. The type of the attachment 14 and the movements it can perform define the number of hydraulic lines 18 (used and connected). The hydraulic line 18 is formed by a flexible hose line arranged in a vent, also called a boom hose vent, between the upper structure 4 and the first link 8, between the first link 8 and the second link 9, and between the second link 9 and the arm 10 in the region of the bolt 19 of the boom assembly 17. The flexible hose vent 21 is also formed between the first attachment point of the attachment 14 and the second attachment point of the arm 10. The flexible boom hose vent 20 and the flexible hose vent 21 enable the individual links of the boom assembly 7 to pivot around the longitudinal axis of the bolt 19 without interrupting or rupturing the hydraulic line 18. The hose vent 21 and the boom hose vent 20 are formed for each additional hydraulic line 18 (not shown here).The portion of the hydraulic line 18 that runs centrally along the link of the boom assembly 7, away from the swivel shaft or bolt 19, is realized by a hard metal tube. The ends of the metal tube are each connected to a flexible hose line to form the hydraulic line 18. The metal tube forms a protected area where the hydraulic line 18 is protected from external damage. In the shown hydraulic line 18, there are two emergency stop valves 23, 24 between the additional valve block 15 and the attachment 14. The emergency stop valves 23, 24 of at least two hydraulic lines 18 are divided into a first emergency stop valve 23 and a second emergency stop valve 24, and are schematically shown as rectangles in FIG. 1. The first emergency stop valve 23 and the second emergency stop valve 24 can close the corresponding hydraulic line 18 at their respective positions. This ensures that the emergency stop valves 23, 24 located near the additional valve block where oil leakage occurs prevent the hydraulic oil located between this emergency stop valve 23, 24 and the hydraulic pump 17 or the hydraulic oil tank 16 in the hydraulic line 18 from leaking. The first emergency stop valve 23 is located in the upper structure 4 on the flow side of the additional valve block 15 away from the pump. The second emergency stop valve 24 is located in the hydraulic line 18 in the area of the arm 10 outside the hose vent 21. As shown in FIG. 1, the position immediately upstream or downstream of the flexible hose line in the area of the arm head bolt 13 in the flow direction is particularly preferred. Empirically, the hose line often leaks in the area of the arm head bolt 13. The above position of the second emergency stop valve 24 makes it possible to maintain the maximum possible amount of hydraulic oil in the hydraulic line 18 in case of such leakage. If an oil leak occurs at the hose vent 21, by closing the second emergency stop valve 24, the oil in the hydraulic line 18 between the second emergency stop valve 24 and the additional valve block 15 can remain in the hydraulic line 18, preventing it from leaking. For example, it is conceivable to use an additional emergency stop valve to protect the boom hose vent 20 of the second link 9 against leakage. At least one emergency stop valve 23, 24 is required for each hydraulic line 18.Even with only the first emergency stop valve 23, most of the hydraulic oil is prevented from leaking in case of a leak in the flexible hose line in the area of the arm head bolt 13. The emergency stop valves 23, 24 are clearly different from the normal pipe burst safety valves that are standardly installed in self-propelled hydraulic work machines. A pipe burst safety valve (not shown) is installed on the attachment 14 and prevents uncontrolled movement of the attachment 14 in case of a pipe burst to protect the operator and people at the construction site. The pipe burst safety valve maintains the pressure of the hydraulic oil in the working chamber of the hydraulic cylinder installed on the attachment 14 or the attachment 14 and enables the attachment 14 to stay in the fixed position. The emergency stop valves 23, 24 interrupt the hydraulic system at at least one point towards the additional valve block 15. Hydraulic oil leaks in the hydraulic line between the break point and the emergency stop valves 23, 24. However, the emergency stop valves 23, 24 prevent a large amount of hydraulic oil from leaking and contribute to environmental protection during the demolition work.

[0065] Figure 3 shows a part of the hydraulic system, which is shown only schematically and is used in particular to control the movement of the attachment 14. The hydraulic valves of the additional valve block 15 are electrically pilot-controlled to move the attachment 14, which is not shown in the figure. The hydraulic pump 17 supplies the additional valve block 15 with the hydraulic pressure required to control the attachment 14 or its hydraulic cylinder. The additional valve block 15 can adjust the volumetric flow of the hydraulic oil through the four hydraulic lines 18 shown as an example and thus control the movement of the attachment 14. There is one first emergency stop valve 23 and one second emergency stop valve 24 for each of the hydraulic lines 18. The first emergency stop valve 23 and the second emergency stop valve 24 are each located in two different areas of the hydraulic line 18. The hose vent 20 closest to the additional valve block and the flexible hose vent 21 in the area of the arm head bolt 13 are shown.

[0066] The first emergency stop valve 23 is arranged in the upper structure 4, that is, in the upper structure area of each hydraulic line 18. Specifically, it is located on the flow side of the additional valve block 15 far from the pump. The second emergency stop valve 24 is arranged in the boom assembly area of each hydraulic line 18. Specifically, as already described above, it is located in the area of the arm 10 outside the upper structure 4 and outside the flexible hose vent 21. In order to enable the hydraulic oil to flow through the emergency stop valves 23, 24 without being blocked, the emergency stop valves 23, 24 are open during the normal operation of the self-propelled hydraulic working machine 1. The emergency stop valves 23, 24 are controlled by an emergency stop actuator 25. When the emergency stop actuator 25 is actuated, the hydraulic lines 18 are closed by the emergency stop valves 23, 24, and the flow of the hydraulic oil is stopped. The emergency stop actuator 25 communicates electronically with the additional valve block 15 and switches the emergency stop valves 23, 24.

[0067] After a leak is detected in one of the hydraulic lines 18 between the attachment 14 and the additional valve block 15, the emergency stop valves 23, 24 are switched and the hydraulic lines 18 are closed. Figure 3 shows the closed state of the emergency stop valves 23, 24, which is achieved by actuating the emergency stop actuator 25.

[0068] In a preferred embodiment, the emergency stop valves 23, 24 are electronically controlled solenoid valves.

[0069] In a preferred embodiment, the leak is detected by the operator, and the operator then actuates the emergency stop actuator 25, the emergency stop valves 23, 24 are switched, and the hydraulic lines 18 are closed. The detection can also be carried out by a sensor assigned to the hydraulic line 18, and the emergency stop actuator 25 can then be automatically actuated.

[0070] In a preferred embodiment, first, an additional valve block 15 is activated by actuating an emergency stop actuator 25, and the additional valve block 15 closes at least two hydraulic lines 18. Next, the emergency stop valves 23, 24 are switched on, and the hydraulic lines 18 are closed with a pre-determinable time delay.

[0071] FIG. 4 shows a further embodiment of a part of a hydraulic system that is generally similar to FIG. 3. In this case, the attachment 14 is hydraulically pilot-controlled by a low-pressure line. The boom hose vent 20 and the hose vent 21 are not depicted. The differences between FIG. 4 and FIG. 3 are explained below. In the embodiment shown in FIG. 4, the first emergency stop valve 23 in the superstructure area of the hydraulic line 18 is realized by a two-way valve 26, which can be connected to the hydraulic oil tank 16 of the hydraulic system via a return line 27. In normal operation, the second emergency stop valve 24 (which is, in one embodiment, an electronically controlled solenoid valve) is open in the boom assembly area, and the two-way valve 26 in the superstructure area is in a first switching position, which allows hydraulic oil to flow from the additional valve block 15 through the hydraulic line 18 to the attachment 14.

[0072] After an oil leak is detected by an operator or a sensor, the second emergency stop valve 24 in the boom assembly area of the hydraulic line 18 is switched on and closed by actuating the emergency stop actuator 25, and the two-way valve 26 switches to the second switching position shown, where the hydraulic oil flows from the additional valve block 15 through the return line 27 to the hydraulic oil tank 16.

[0073] It is conceivable to use more than two emergency stop valves 23, 24 per hydraulic line 18.

[0074] In both types of hydraulically pilot-controlled hydraulic systems, one electrically and one hydraulically, oil leakage detection can be carried out by the operator or a sensor. The emergency stop actuator 25 can be designed, for example, as an operating button in the cab 5 or on the boom assembly 7, or be accessible via the control unit of the self-propelled hydraulic work machine 1, which has the operating elements necessary to control the self-propelled hydraulic work machine 1. By actuating the emergency stop actuator 25, the emergency stop valves 23, 24 are switched on and the flow of hydraulic oil is stopped. By actuating the emergency stop actuator 25 again, the emergency stop valves 23, 24 can be switched back and the hydraulic line 18 to the attachment 14 can be opened again. The emergency stop valves 23, 24 are switched back when the oil leakage in the hydraulic line 18 has stopped. If the leakage is detected by a sensor, an alarm may be issued, whereby the operator can actuate the emergency stop actuator 25. However, it is also possible that the emergency stop valves 23, 24 and / or an additional valve block 15 are automatically activated by a sensor detecting a pressure drop. In a further embodiment, it is intended to use an emergency stop valve that automatically closes in case of a pressure drop in the hydraulic line 18.

[0075] Finally, Fig. 5 shows a valve arrangement having two emergency stop valves. The valve arrangement includes a first 2 / 2-way valve 30 connected to a first pressure line P1 and a first working line A1, a second 2 / 2-way valve 31 connected to a second pressure line P2 and a second working line A2, a 4 / 2-way valve 32 connected to the second working line A2, here shown together with the second 2 / 2-way valve 31 and to an inflow pressure line Pa, an outflow line T, a first control line C and a blocked connection D, and a shuttle valve 33 having a first blockable inflow 34 and a second blockable inflow 35 and an outflow 36. The 2 / 2-way valves are emergency stop valves included in the above meaning and can be arranged and used accordingly.

[0076] The 4 / 2-way control valve 32 can be actuated electrically via the electrical line 37. In the inoperative position shown in FIG. 5, the inflow pressure line Pa is connected to the first control line C, and the outflow line T is connected to the permanently blocked connection D of the 4 / 2-way control valve 32. In the electrically actuated position, the inflow pressure line Pa is connected to the permanently blocked connection D and thus closed. The control line C is connected to the outflow line T and is thus essentially depressurized. The control line C is connected to the first 2 / 2-way valve 30 and the second 2 / 2-way valve 31 and advances them to the closed position when the control line C is pressurized.

[0077] In the inoperative position shown, the 2 / 2-way valve 30 and the 2 / 2-way valve 31 are preloaded to the closed position by the spring 39 (NC). Both valves are controlled by the inflow pressure in the connection lines P1 and P2 and the working lines A1 and A2. For this purpose, the pilot line 40 is provided to the 2 / 2-way valve 30, which runs from the pressure line P1 to the working chamber (not shown) on the opposite side of the spring 39. A further pilot line 41 runs from the working line A1 to the same working chamber. The geometry of the spring 39 and the movable valve member and the working chamber (not shown) is selected such that the 2 / 2-way valve 30 switches to the open position against the force of the spring 39 at an inflow pressure of approximately 2 bar. The electrical actuation of the direction control valve 30 is not required and not provided. It is purely pressure-controlled. The same applies to the 2 / 2-way control valve 31, where the pilot line 43 runs from the pressure line P2 and the pilot line 44 runs from the working line A2 to the corresponding working chamber. This valve is also pressure-controlled and opens, for example, when an inflow pressure of 2 bar is applied.

[0078] In the inoperative position shown in FIG. 5, the two 2 / 2-way valves 30 and 31 are thus closed. When pressure is built up in pressure line P1 or P2, each 2 / 2-way valve is pilot-controlled to the open position via pilot line 40 or 43. However, at the same time, a pressure higher than the pressure built up in pressure line P1 or P2 is applied to the outflow section 36 of shuttle valve 33 via connection section 34 or 35 of shuttle valve 33. This higher pressure then exists in the inflow pressure line Pa and is applied to control line C via 4 / 2-way valve 32 in the inoperative position, which in turn directs this higher pressure towards the spring side of 2 / 2-way valves 30 and 31, advancing the movable valve elements of 2 / 2-way valves 30 and 31 to the closed position. The respective control surfaces of 2 / 2-way valves 30 and 31 are dimensioned such that 2 / 2-way valves 30 and 31 remain closed at the same pressure in control line C and pilot lines 40 and 43.

[0079] In order to be able to start the working machine from this position of the valve device using the hydraulic tool 47 connected to the working lines A1 and A2, the electric line 37 to which the normally closed emergency stop switch 45 is connected in series is supplied with an operating voltage of, for example, 24V. This switches the 4 / 2-way valve 32 to the operating position, where the control line C is connected to the outlet T and the inlet pressure line Pa is connected to the blocked connection D. If pressure is applied from the hydraulic system of the working machine, for example, to the pressure line P1, the 2 / 2-way control valve, for example, is pressurized with the corresponding pressure via the pilot line 40. The shuttle valve 33 then directs this pressure to the outlet 36 and the pre-pressure line Pa as described above, where the latter is switched to the connection D in the 4 / 2-way control valve 32 and is thus closed. The control line C is connected to the outlet T and is thus depressurized. This means that there is no pressure in the control line C opposing the opening of the 2 / 2-way valve 30. The 2 / 2-way valve 30 switches to the open position. The return flow is generated from the hydraulic unit 47, which leads to an increase in pressure in the working line A2. This pressure increase opens the 2 / 2-way valve 31 via the pilot line 44. Thus, the valve device described in this regard is hydraulically permeable and the hydraulic unit 47 can be operated in the normal way.

[0080] The same applies in the reverse case. If the hydraulic pressure is first applied to the pressure line P2, the 2 / 2-way control valve 31 opens first, and then the 2 / 2-way control valve 30 also opens due to the increase in pressure in the working line A1.

[0081] The valve device can be attached, for example, to the boom or arm of an excavator. The pressure lines P1 and P2 can then be permanently mounted as pipelines on the boom or arm and connected to the valve device. The valve device can each be designed as a valve block. The valve block is preferably attached to one side of the boom or arm. For example, the ball valve is attached as usual. The flexible hose vents 48 and 49 run from the valve device to the hydraulic unit 47, which is essential for the movable hydraulic unit 47. If during operation, as described in detail above, the hose vents 48, 49 catch on a reinforcing bar protruding, for example, during the demolition of a building and break, a large amount of hydraulic oil will leak from the break point of the conventional hydraulic system. In such a case, the operator of the work machine can activate the emergency stop switch 45 and de-energize the 4 / 2-way valve 32. It then assumes the inoperative position shown in FIG. 5. If the pressure in the hydraulic line drops below the opening pressure of the 2 / 2-way valve due to leakage, the valve automatically closes. At that time, the hydraulic pressure generated by the hydraulic system in the pressure line P1 or P2 exists in the shuttle valve 33. The higher of the two pressures is applied to the outflow part 36 and sent to the control line C. Together with the spring force of the spring 39, the control line C then brings both the 2 / 2-way valves 30 and 31 to the closed position. As a result, if the hose vents 48, 49 are damaged and the emergency stop switch 45 is activated, the hydraulic system in the valve device is completely closed so that no further hydraulic fluid can leak from the hydraulic system.

[0082] Here, it should be emphasized that the valve device does not replace the function of a conventional hose burst safety device. The hose burst safety device can also be directly applied to two connections of the hydraulic unit 47 to prevent, for example, the boom or suspended weight from suddenly dropping when the hose vents 48, 49 are damaged. Such a hose burst safety device automatically reacts to a high volume flow exceeding a predetermined limit value. Basically, the hose burst safety device is an automatic, volume flow-controlled non-return valve. However, the hose burst safety device cannot prevent a large amount of hydraulic fluid from leaking out of the hydraulic system when the hose vents 48, 49 are damaged and the hose bursts.

[0083] The 2 / 2-way control valves 30 and 31 can have the same design, but preferably they are selected such that, for example, one of the 2 / 2-way control valves has a larger opening cross-section than the other to adapt to different volume flows in a double-acting hydraulic unit.

[0084] Figure 6 shows a schematic view of another valve device having an emergency stop valve. The double-acting hydraulic cylinder 50 of the hydraulic consumer has two chambers. The first chamber 51 is connected to the first working line 52. The second chamber 53 is connected to the second working line 54. The two working lines 52, 54 are connected at the upper side to a volume control valve (not shown), which controls the volume flow through the working lines 52, 54. The volume control valve can be part of an additional valve block. The shown valve device includes a first 2 / 2-way valve 55 having a port P connected to the first pressure line 56 and a port A connected to the first working line 52. In the first position of the 2 / 2-way valve 55, the flow from port A to port P and the flow from port P to port A are blocked. In the second position, the valve 55 allows a free flow from port A to port P and the reverse flow from port P to port A. In the shown first position (non-operating position, closed position), the 2 / 2-way valve 55 is pre-loaded by a spring 57. The 2 / 2-way valve 55 has a control line 58, which is connected to a pilot valve 59. The control line 58 is connected to the acting chamber (shown as a rectangle) on the side of the spring 57. Depending on the technical implementation, the spring 57 can be positioned in the acting chamber. The 2 / 2-way valve 55 is also controlled by the upstream pressure in the first pressure line 56 and the first working line 52. For this purpose, a pilot line 60 is provided to the 2 / 2-way valve 55, which runs from the first pressure line 56 to the acting chamber on the side opposite to the spring 57. This is a schematic view. The pilot line 60 can be the effective area of the piston of the direction control valve. A further pilot control line 61 runs from the first working line 52 to the same acting chamber. Here too, the active surface of the direction control valve can be connected to the first working line to carry out the functions shown schematically. The geometric design of the spring 57 and the movable valve member is selected such that the 2 / 2-way valve 55 switches to the open position against the force of the spring 57 at an upstream pressure of 2 bar, for example, in the first working line 52 or the first pressure line 56. The electrical actuation of the 2 / 2-way valve 55 is not required and not provided.It is purely pressure-controlled. The 2 / 2-way valve 55 can be moved to a second closed position by actuation via the control line 58. The closing pressure of the spring is about 4 - 6 bar, preferably 2 bar.

[0085] The pilot valve 59 connected to the control line 58 can be designed as a 3 / 2-way valve. However, it is also conceivable to use a 4 / 2-way valve. A 3 / 2-way valve is shown, which has a first connection A1 in the first position, which automatically switches and is connected to the pressure reduction line 62. The second connection A2 is connected to the control line 63, which controls the second 2 / 2-way valve 64 and is branched to the control line 58 of the first 2 / 2-way valve 55. Both 2 / 2-way valves 55, 64 are thus controlled by the second connection A2. The second 2 / 2-way valve 64 is designed similarly to the first 2 / 2-way valve 55 and is arranged between the second pressure line 65 and the second working line 54. The control line 63 of the second 2 / 2-way valve 64 acts in the same direction as the spring action and moves the valve 64 to the closed position when the control line 63 is pressurized.

[0086] The third connection part A3 of the pilot valve 59 is connected to the pressure supply line 66. In the first position of the 3 / 2-way control valve, the flow of hydraulic oil from connection part 3 to connection part 2 is allowed. The control line 63 is pressurized by the pressure of the hydraulic oil from the pressure supply line 66. In the second position of the 3 / 2-way valve, connection part 3 is automatically switched, and the flow of hydraulic oil from connection part 2 to connection part 1 is allowed. The pressure is relieved in the control line 63, and thus in the control line 58, and the hydraulic oil flows into the pressure reduction line 62. The pilot control valve 59 is pre-loaded to the first position by a spring. The pilot control valve 59 can be electrically actuated by the electrical line 67. The normally closed emergency stop switch 68 is connected in series in the electrical line 67 and is supplied with an operating voltage of, for example, 24V. This switches the pilot valve 59 to the operating position, where the control line 63 is connected to the pressure reduction line 62, and the pressure supply line 66 (also known as the pre-pressure line) is connected to the blocked connection part A3. Furthermore, the pilot control valve 59 has an optional emergency manual override, which is designed such that the pilot valve 59 can be switched to the operating position by actuating the emergency stop override.

[0087] Figure 6 shows the first position (not the operating position) of the pilot valve 59.

[0088] In the non-operating position shown in Figure 6, the two 2 / 2-way valves 55 and 64 are thus closed. When pressure is created in the pressure line 56 or 65, each of the 2 / 2-way valves 55, 64 is pilot-controlled to the open position by its respective pilot control line 60 or 69. However, at the same time, the four connection parts A of the two 2 / 2-way valves 1 ,A 2 ,P 1 ,P 2The highest pressure among the pressures present in is applied by the pressure supply line 66 to the connection A2 of the pilot valve 59 and thus to the control lines 58, 63. This then applies this high pressure to the spring sides of the 2 / 2-way valves 55 and 64, thereby guiding the movable valve elements of the 2 / 2-way valves 55 and 64 to the closed position. The respective control surfaces of the 2 / 2-way valves 55 and 64 are dimensioned such that the 2 / 2-way valves 55 and 64 remain closed at the same pressure in the control lines 58, 63 and the pilot lines 60, 61 and 69, 70.

[0089] The pressure supply line 66 is connected for this purpose to two working lines 52, 54 and two pressure lines 56, 65. The branches to the four lines 52, 54, 56, 65 are arranged in parallel, and non-return valves 71 are arranged in each of the branches, which open in the direction of the pressure supply line 66 when a high pressure is applied to each line. If, for example, the pressure line 56 receives the highest pressure, the non-return valve 71 in the line branching off from the pressure line 56 opens and the parallel non-return valves 71 are thereby closed. This is because the pressure applied there is low. The pressure of the hydraulic oil in the pressure line 56 is supplied into the pressure supply line 66, and this pressure is available for the control lines 63, 58 as explained above.

[0090] In order to be able to start the working machine from this position of the valve device using the hydraulic consumer 50 connected to the working lines 52 and 54, an operating voltage is applied to the electrical line 67 and the 3 / 2-way valve 59 is switched to the working position. If pressure is applied from the hydraulic system of the working machine up to, for example, the pressure line 56, the 2 / 2-way control valve 55 arranged in the line, for example, is pressurized with the corresponding pressure via the pilot line 60. The non-return valve 71 assigned to the pressure line then sends this pressure, as described above, to the pressure supply line 66, which is switched to the connection A3 in the pilot valve 59 and is thus blocked. The control line 63 is connected to the pressure reduction line 62. In order to reduce the pressure in the control line, the pressure reduction line 62 is connected to the two working lines 52, 54 and the two pressure lines 56, 65. The branches for the four lines 52, 54, 56, 65 are arranged in parallel and non-return valves 72 are arranged in each of the branches, which open in one direction of each of the four lines 52, 54, 56, 65 when a high pressure is applied in each line. If, for example, the pressure reduction line 62 receives a pressure higher than the pressure in the pressure line 65, the non-return valve 72 opens in the line branching off from the pressure line 65 and the pressure in the control lines 63, 58 can be reduced, so that there is at least a lower pressure in the control lines 63, 58 than the pressure in the working line 56, which would oppose the opening of the 2 / 2-way valves 55, 64. For example, if there is a return flow from the hydraulic consumer 50, it will lead to an increase in the pressure in the working line 54. This pressure increase causes the 2 / 2-way valve 64 to open via the pilot line 70, so that the valve device described in this regard is hydraulically permeable and the hydraulic consumer can be operated in the normal way.

[0091] The same also applies in the reverse case. If the hydraulic pressure is first applied to the pressure line 65, the 2 / 2-way control valve 64 opens first and then the 2 / 2-way control valve 55 also opens due to the increase in pressure in the working line 52.

[0092] The valve device can be attached, for example, to the superstructure of a self-propelled machine or, in the case of an excavator, to the boom or arm. The pressure lines 56 and 65 can then be permanently attached as pipelines to the boom or arm and connected to the valve device. The valve device can each be designed as a valve block. The valve blocks are preferably each attached to one side of the boom or arm. For example, the ball valves are attached in the conventional manner. It is also conceivable to arrange the valve device in the superstructure. Depending on how the hydraulic consumer is designed, one or more working lines are provided. For example, the hydraulic consumer can also be the boom cylinder 11, the intermediate boom cylinder 12, or the arm cylinder.

[0093] The flexible hose line runs curved from the valve device to the hydraulic consumer 50. These areas are referred to as flexible hose bends and are different from pipe bends (which are purchased as a component and have a fixed rigid geometry). The flexible hose bend is an essential part for a movable hydraulic unit. If, as described in more detail above, the hose bend catches on a reinforcing bar protruding during the demolition of a building and breaks, a large amount of hydraulic oil will leak from the break point of a conventional hydraulic system. In such a case, the operator of the work machine can activate the emergency stop switch 68 and de-energize the pilot valve 59. It will then be in the position shown in Figure 6. If the pressure in the hydraulic line drops below the opening pressure of the 2 / 2-way valve due to leakage, the valve will automatically close. The higher of the two pressures in the pressure line 56 or 65 and the working line without leakage is supplied to the pressure supply line 66 and sent to the control lines 58, 63. Together with the spring force of the spring 57, the control lines 58, 63 then bring both the 2 / 2-way valves 55, 64 to the closed position. As a result, in the case of a leakage in the working line, for example, if the flexible hose bend is damaged and the emergency stop switch 68 is activated, the hydraulic system in the valve device is completely closed so that no further hydraulic fluid can leak from the hydraulic system.

[0094] Here, it should be emphasized that the valve device does not replace the function of a conventional hose rupture safety device. The hose rupture safety device can also be directly provided to two connection parts of the hydraulic unit 50 to prevent, for example, the boom or the suspended weight from suddenly dropping when the hose vent is destroyed. Such a hose rupture safety device automatically reacts to a high volume flow exceeding a predetermined limit value. Basically, the hose rupture safety device is an automatic, volume flow-controlled non-return valve. However, the hose rupture safety device cannot prevent a large amount of hydraulic fluid from leaking from the hydraulic system itself when the hose vent ruptures.

[0095] The two 2 / 2-way control valves 55, 64 can have the same design, but they are preferably selected such that one of the 2 / 2-way control valves has a larger opening cross-section than the other to adapt to different volume flows in, for example, a double-acting hydraulic unit or a return-sensitive attachment (such as a hydraulic hammer).

Claims

1. A valve device for a self-propelled work machine (1) having a hydraulic consumer (47, 50), the valve device being characterized by having the following: - At least one directional control valve (30, 31, 55, 64) connected to the pressure lines (P1, P2, 56, 65) and the working lines (A1, A2, 52, 54) of the hydraulic consumer (47, 50), - A hydraulic control line (C, 58, 63) designed to move at least one directional control valve (30, 31, 55, 64) to a first position, - A pilot valve (32, 59) connected to the hydraulic control line (C, 58, 63), - A pressure supply line (Pa, 66), and - A pressure reduction line (T, 62), provided that the pilot valve (32, 59) is designed to selectively connect the hydraulic control line (C, 58, 63) to the pressure supply line (Pa, 66) and the pressure reduction line (T, 62).

2. The valve device according to claim 1, characterized in that when the first position of at least one directional control valve (30, 31, 55, 64) is a closed position, the flow is blocked in both directions.

3. At least one directional control valve (30, 31, 55, 64) is spring-biased towards the first position, and at least one directional control valve (30, 31, 55, 64) has two pilot control lines (40, 41, 43, 44, 60, 61, 69, 70) connected to the working chamber on the side opposite to the spring (39, 57), the first pilot control line (40, 43, 60, 69) is connected to the pressure line (P1, P2, 56, 65), and the second pilot control line (41, 44, 61, 70) is connected to the working line (A1, A2, 52, 54). The valve device according to claim 1 or 2, characterized by this.

4. The valve device according to any one of claims 1 to 3, characterized in that the pilot valve (32, 59) is a 3 / 2 or 4 / 2 directional valve.

5. The pilot valve (32, 59) is electrically operable and, in the non-operating position, connects the pressure supply line (Pa, 66) to the hydraulic control line (C, 58, 63), and in the operating position, connects the hydraulic control line (C, 58, 63) to the pressure reduction line (T, 62). The valve device according to any one of claims 1 to 4, characterized by this.

6. The pilot valve (32, 59) can be electrically actuated to an operating position, but can be deactivated by an emergency stop switch (45, 68). The valve device according to any one of claims 1 to 5, characterized in that.

7. The emergency stop switch (45, 68) is arranged in the working chamber of the working machine so that it can be manually actuated. The valve device according to claim 6, characterized in that.

8. The valve device includes a first direction control valve (30, 55) and a second direction control valve (31, 64), which are respectively connected to the pressure lines (P1, P2, 56, 65) and working lines (A1, A2, 52, 54) of a common hydraulic consumer (47, 50), and a plurality of hydraulic control lines (C, 58, 63) are connected to each other so as to guide the two-way control valve to a closed position when they are pressurized. The valve device according to any one of claims 1 to 7, characterized in that.

9. The valve device includes a shuttle valve (33) having a first blockable inlet (34), a second blockable inlet (35), and an outlet (36). The first blockable inlet (34) of the shuttle valve is connected to the first pressure line (P1) of the first direction control valve (30), the second blockable inlet (35) of the shuttle valve is connected to the second pressure line (P2) of the second direction control valve (31), the outlet (36) of the shuttle valve is connected to the pressure supply line (Pa), and the shuttle valve (33) is designed such that the pressure line (P1, P2) having the highest pressure among the first pressure line (P1) and the second pressure line (P2) can be connected to the pressure supply line (Pa). The valve device according to claim 8, characterized in that.

10. The pressure supply line (66) is connected to the pressure lines (56, 65) and the working lines (52, 54) via branches, the branches exist in parallel, each having a non-return valve (71), and the non-return valve (71) is arranged such that the highest pressure among the pressures existing in the pressure lines and the working lines (52, 54, 56, 65) is guided to the pressure supply line (66). The valve device according to any one of claims 1 to 8, characterized in that.

11. The valve device according to any one of claims 1 to 10, characterized in that the pressure reduction line (T) is a tank line that can be connected to a tank.

12. The pressure reduction line (62) is connected to the pressure lines (56, 65) and the working lines (52, 54) via branches, the branches are present in parallel, each having a non-return valve (72), and the non-return valve (72) opens to one of the pressure lines and working lines (52, 54, 56, 65) having a lower pressure when pressure is applied to the pressure reduction line (62). The valve device according to any one of claims 1 to 10.

13. The valve device according to any one of claims 1 to 12, characterized in that the first direction control valve (30, 55) and / or the second direction control valve (31, 64) is a 2 / 2-way valve.

14. Use of the valve device according to any one of claims 1 to 13 in the working lines of hydraulic consumers (47, 50) in a self-propelled working machine to close the working lines (52, 54, A1, A2) when hydraulic oil leakage occurs in the working lines to prevent a large amount of hydraulic oil from leaking from the leakage point.

15. A self-propelled working machine (1) having a lower structure (3), an upper structure (4), a boom assembly (7), and a hydraulic system, the hydraulic system including a hydraulic pump (17), a volume control valve, hydraulic consumers (47, 50), and at least two hydraulic lines (18, 52, 54, 56, 65, A1, A2, P1, P2), the volume control valve being designed to adjust the oil flow through at least one of the hydraulic lines (18, 52, 54, A1, A2) to operate the hydraulic consumers (47, 50). In the self-propelled working machine (1), at least one of the hydraulic lines (18, 52, 54, 56, 65, A1, A2, P1, P2) has a direction control valve (30, 31, 55, 64), and the direction control valve (30, 31, 55, 64) is designed to close the hydraulic lines (18, 52, 54, 56, 65, A1, A2, P1, P2) in case of leakage of the hydraulic line. A self-propelled hydraulic working machine characterized by this.

16. The self-propelled work machine according to claim 15, characterized in that the direction control valves (30, 31, 55, 64) are arranged between the volume control valve and the hydraulic consumers (47, 50).

17. The self-propelled work machine according to claim 15 or 16, characterized in that the self-propelled work machine includes the valve device according to any one of claims 1 to 13, and the direction control valves (30, 31, 55, 64) are part of the valve device.

18. A method for minimizing hydraulic oil loss in the self-propelled work machine according to any one of claims 15 to 17 when hydraulic oil leaks in the working lines (52, 54, A1, A2), the method including the following consecutive steps: (a) If a leak occurs in the hydraulic lines (52, 54, A1, A2) between the hydraulic consumers (47, 50) and the direction control valves (30, 31, 55, 64), move the direction control valves (30, 31, 55, 64) to the closed position, thereby closing the hydraulic lines (52, 54, A1, A2), (b) Ensure that the locking in the closed position is maintained until the leak is rectified, (c) After the leak is rectified, return the direction control valves (30, 31, 55, 64) and / or the valve device to the initial state before the leak.

Images