Hydraulic system for a workpiece machining device as well as workpiece machining device and method for operating a workpiece machining device

Abstract

The invention provides a hydraulic system for a workpiece machining device, a workpiece machining device comprising such a hydraulic system, and a method for operating a workpiece machining device. The hydraulic system (100; 200; 300) comprises: a valve device (150; 250) which is switchable between at least one cooling position and at least one working position, wherein in the cooling position, a coolant flow emanating from the coolant pump (181) is directed by the valve device (150; 250) into a cooling path (120) for cooling the workpiece processing device (1000; 2000; 3000), and wherein in the working position the coolant flow is directed by the valve device (150; 250) for hydraulic interaction with at least one actuator (140; 340).

Description

Field of invention

[0001] The invention relates to a hydraulic system for a workpiece processing device and to a workpiece processing device with such a system. Furthermore, the invention relates to a method for operating a workpiece processing device. The workpiece processing device may, in particular, be a welding device, a soldering device, a cutting device, or the like, especially a robotic device. Technical background

[0002] Workpiece processing equipment or components thereof often generate considerable heat and therefore require cooling. For this purpose, workpiece processing equipment is frequently equipped with a cooling system in which a coolant is typically circulated.

[0003] Furthermore, workpiece machining equipment is frequently equipped with working cylinders, preferably hydraulic or pneumatic, which are both actuated and robust against unwanted adjustment. For example, couplings of tools to workpiece machining equipment can be accomplished using such hydraulic or pneumatic working cylinders. For this purpose, working cylinders are used, for instance, which are pre-tensioned to close the coupling and which must be hydraulically actuated against the pre-tension to open the coupling.

[0004] Pneumatic working cylinders, for example, are typically equipped with compressed air connections in workshops. These connections provide compressed air to actuate the cylinders, particularly to release couplings, such as for tool changes. Such workpiece processing devices therefore comprise a primary fluid or compressed air system with lines for actuating the working cylinder (a hydraulic or pneumatic system), and a second, separate fluid system with its own lines for cooling the workpiece processing device. Consequently, these devices are correspondingly large and complex to maintain and manufacture. Furthermore, an external compressed air supply is required.

[0005] GB 867815 A describes a spot welding machine that uses a fluid first to actuate a hydraulic working cylinder and then to cool the spot welding machine. The pressure conditions in this fluid system must therefore be balanced for the various applications. Furthermore, a relatively large amount of fluid is always present in the spot welding machine, as both the cooling and actuation of the hydraulic working cylinder are constantly in operation.

[0006] Document DE 10 2018 112 665 A1 relates to a hydraulic system with a pump connected to a coolant line and an activation line. This system supplies coolant from different fluid sources to two consumers. The pump is a reversible pump. A hydraulic parking lock actuator is also provided, which is connected to the coolant line via a switching valve.

[0007] Document DE 29 48 038 A1 discloses a welding cylinder used in electric resistance welding. The cylinder comprises a piston with a piston rod and a cooling circuit for a coolant to prevent overheating of the welding cylinder. Summary of the invention

[0008] It is therefore an object of the present invention to provide an improved hydraulic system for a workpiece machining device and an improved method for operating a workpiece machining device.

[0009] This problem is solved by the subject matter of the independent patent claims.

[0010] According to a first aspect, the invention provides a hydraulic system for a workpiece machining device, comprising: a valve device which can be switched between at least one cooling position and at least one working position, wherein, in the cooling position, the valve device directs a coolant flow originating from a coolant pump into a cooling path for cooling the workpiece processing device, wherein, in the operating position, the coolant flow is directed by the valve device for hydraulic interaction with an actuator; and a control valve which is hydraulically arranged between the valve device and the hydraulic actuator, and by means of which it is adjustable: which is hydraulically connected to the coolant pump by at least two working chambers of the hydraulic actuator, or which is hydraulically connected to the coolant pump by at least two hydraulic actuators, when the valve device is in the working position.

[0011] The valve device is thus configured with a number of predetermined positions, including at least one cooling position and one operating position, and optionally further positions such as a neutral position, at least one further cooling position, at least one further operating position, and / or the like. The valve device is always in one of the predetermined positions and is switchable between all predetermined positions, whereby, in some cases, further positions must first be traversed from certain positions to reach some positions.

[0012] The valve device is preferably an electro-hydraulic (optionally a mechanical-hydraulic) control unit that only directs the coolant flow, while the coolant pump alone provides the drive for the coolant. The coolant can be a suitable fluid, in particular a liquid such as water or oil.

[0013] The hydraulic interaction can consist, for example, of actuating the hydraulic working cylinder, in particular of moving a piston of the working cylinder in one direction or the other, i.e., to close or open the working cylinder. The valve device is preferably switchable by electrical signals, for example, by electrical signals from a control unit.

[0014] The hydraulic system according to the invention can include, in addition to the valve device, further elements, in particular the coolant pump, a coolant tank from which the coolant pump pumps out the coolant, the coolant, the working cylinder, a pressure tank and / or the like.

[0015] The working cylinder can, for example, be part of a coupling by means of which a respective tool can be connected to the workpiece processing device. Actuating the working cylinder can thus correspond to opening or closing the coupling. Preferably, in this case, the working cylinder is pre-tensioned in the direction of closing the coupling and can be opened by actuation. However, other variants are also conceivable.

[0016] Furthermore, various sensors can be provided to monitor the states of the hydraulic system, for example, a position sensor for the position of the working cylinder (e.g., end-position detection), one or more pressure sensors at different positions within the hydraulic system, and / or similar devices. The sensor signals from the sensor(s) can each be transmitted to the control unit, which may be configured to generate control signals based, among other things, on the received sensor signals.

[0017] According to some preferred embodiments, variants, or refinements of embodiments, the system further comprises at least one actuator, wherein the actuator is a hydraulic working cylinder. Preferably, the hydraulic working cylinder is designed and arranged such that, when the valve device is in the operating position, the hydraulic interaction with the coolant actuates the hydraulic working cylinder against a preload. In this way, it can be ensured that the hydraulic working cylinder is actuated, for example, opened, only by sufficient hydraulic pressure. This is particularly suitable when using the hydraulic working cylinder in a clutch. Alternatively, the hydraulic actuator can also be, for example, a hydraulic motor.

[0018] According to some preferred embodiments, variants, or refinements of embodiments, the valve device can also be switched to a zero position in which the coolant pump is hydraulically connected neither to the cooling path nor to the hydraulic actuator. Preferably, the system is designed such that, in the zero position, the working path leading to the hydraulic actuator is connected to a pressure tank. In this way, a holding force exerted by the working cylinder can still be ensured.

[0019] According to the invention, the system comprises a control valve, which is hydraulically arranged between the valve device and the hydraulic actuator, in particular a working cylinder, and by means of which it is adjustable which of at least two working chambers of the hydraulic actuator is hydraulically connected to the coolant pump, or which of at least two hydraulic actuators is hydraulically connected to the coolant pump when the valve device is in the working position. In this way, the working cylinder can be actuated in different directions, for example, in the opening or closing direction if there are exactly two working chambers, by appropriately adjusting the control valve.

[0020] According to some preferred embodiments, variants, or refinements of embodiments, a pressure tank is connected between the control valve and the valve assembly. This pressure tank allows a holding force to be maintained on the hydraulic actuator.

[0021] The control valve can, in particular, be a control valve with at least one connection to the valve assembly, wherein a pressure tank is connected at a point between one of the at least one connection to the valve assembly and a corresponding connection of the valve assembly. This can be used to ensure the holding force on the hydraulic actuator. The control valve can, for example, be a 4 / 2 hydraulic valve with two connections to the valve assembly and two connections to the hydraulic actuator.

[0022] According to some preferred embodiments, variants or refinements of embodiments, the valve device can additionally be switched into a further working position in which the coolant flow is directed by the valve device to a further hydraulic interaction with the (same) actuator or to a hydraulic interaction with a further actuator, wherein the hydraulic interaction in the working position and the further hydraulic interaction in the further working position with the actuator, or the interaction with the actuator and the interaction with the further actuator, are in particular opposite in direction.

[0023] According to some preferred embodiments, variants or refinements of embodiments, the workpiece processing device is a robotic workpiece processing device, for example a welding device.

[0024] The invention also provides, according to a second aspect, a workpiece processing device comprising a hydraulic system according to an embodiment of the first aspect of the present invention. The workpiece processing device is, in particular, a robotic device; that is, it preferably has a robot arm by means of which a tool can be guided. According to some preferred embodiments, variants, or refinements of embodiments, the workpiece processing device according to the invention can be or comprise a welding device, a soldering device, a cutting device, and / or the like.

[0025] According to a third aspect, the invention also presents a method for operating a workpiece processing device, comprising the steps of: Pumping coolant from a coolant tank using a coolant pump to create a coolant flow; setting a valve device to at least one cooling position (i.e., either to a single cooling position, or to one of several cooling positions of the valve device and / or to several cooling positions in succession), whereby the coolant flow is directed into a (respective) cooling path for cooling the workpiece machining device;

[0026] Setting the valve device to at least one working position (i.e., either to a single working position, or to one of several working positions of the valve device and / or to several working positions in succession), thereby directing the coolant flow into a working path for hydraulic interaction with at least one (respective) actuator; and Adjusting a control valve which is hydraulically arranged between the valve device and the hydraulic actuator in order to adjust - which of at least two working chambers of the hydraulic actuator is hydraulically connected to the coolant pump or - which of at least two hydraulic actuators is hydraulically connected to the coolant pump when the valve device is in the working position.

[0027] As explained above, the valve assembly can be set to a variety of different positions: in addition to the aforementioned cooling position and operating position, these can include, for example, a neutral position, one or more further cooling positions, one or more further operating positions, and so on. Accordingly, the method, according to its variants, can include at least one further step involving setting the valve assembly to any of these other positions. Each cooling position can be configured to direct the coolant flow into its own dedicated cooling path. Each operating position can be configured to direct the coolant flow to actuate one or more associated actuators.

[0028] According to some preferred embodiments, variants, or refinements of embodiments, the workpiece machining device is used to machine a workpiece simultaneously with the pumping of the coolant and the adjustment of the valve device. In other words, the adjustment (or: repositioning) of the valve device can be performed while the workpiece machining device is in operation.

[0029] Further preferred embodiments, variants and further developments of embodiments are shown in the dependent claims and in the description with reference to the figures. Brief description of the characters

[0030] The invention is explained in more detail below with reference to exemplary embodiments shown in the figures of the drawings. The partially schematic representations show: Fig. 1 a schematic representation of a hydraulic system according to one embodiment of the present invention and of a workpiece processing device according to a further embodiment of the present invention; Fig. 2 a schematic representation of a hydraulic system according to yet another embodiment of the present invention and of a workpiece processing device according to yet another embodiment of the present invention; Fig. 3 a schematic representation of a hydraulic system according to yet another embodiment of the present invention and of a workpiece processing device according to yet another embodiment of the present invention; Fig. 4 schematically shows an example of a design variant; Fig. 5 schematically shows a further design variant; and Fig. 6 a schematic flowchart to explain a method according to yet another embodiment of the present invention.

[0031] In all figures, identical or functionally equivalent elements and devices are designated with the same reference numerals unless otherwise specified. The designation and numbering of the process steps do not necessarily imply a sequence, but serve for better differentiation, although in some variants the sequence may correspond to the numbering sequence. Detailed description of the figures

[0032] Fig. Figure 1 shows a schematic representation of a hydraulic system 100 according to an embodiment of the present invention and of a workpiece processing device 1000 according to a further embodiment of the present invention.

[0033] The hydraulic system 100 includes in the Fig. In the example shown, a coolant tank 180, in which a coolant is arranged and stored, and a coolant pump 181, by means of which the coolant can be pumped from the coolant tank 180 and a coolant flow can be generated from the coolant tank 180. The coolant pump 181 can be driven, for example, by a motor 182, in particular an electric motor, but also by other drive forms.

[0034] Immediately after the coolant pump 181, the coolant enters a line path 160 of the hydraulic system 100. In the Fig. As shown in Figure 1, this splits into two branches: a first branch 161, which leads back to the coolant tank 180 via a line path pressure relief valve 183, and a second branch 162, which leads to a valve device 150 of the hydraulic system 100.

[0035] The line path pressure relief valve 183 is set such that, when the pressure in line path 160 exceeds a first pressure threshold, it allows coolant from the first branch 161 to flow into the coolant tank 180. Instead of the line path pressure relief valve 183, another pressure relief method can be used, such as motor current control for the motor 182. For example, the pressure in line path 160 may be between 2 bar and 10 bar, particularly between 3 bar and 6 bar, and the line path pressure relief valve 183 may be selected and / or set accordingly.

[0036] The valve device 150 is in the Fig. In the example shown, a 4 / 2 hydraulic valve has two pump-side ports 151, 153 and two outlet-side ports 152, 154. One of the two pump-side ports 151 is hydraulically connected to the second branch 162 of the line path 160. The two possible positions of the valve assembly 150 consist of a cooling position (left in Fig. 1) and a working position (right in Fig. 1).

[0037] In the cooling position, the first pump-side port 151 is connected via the valve device 150 to a first outlet-side port 152, and the second pump-side port 153 to a second outlet-side port 154. The first outlet-side port 152 leads to a cooling path 120 of the hydraulic system 100, by means of which a workpiece machining device 1000 is cooled. Fig. Figure 1 shows the workpiece processing device as an example of a robot welding machine with a welding torch 1001 and a robot arm 1002 which guides the welding torch 1001.

[0038] The cooling path 120 has a first cooling path line 121, which leads from the first output-side connection 152 to the workpiece machining device 1000, and a second cooling path line 122, which carries the coolant back to the coolant tank 180 after the cooling of the workpiece machining device 1000, via an optional filter 184.

[0039] The second pump-side connection 153 is connected to the second cooling path line 122 via a check valve 171, whereby the check valve 171 only allows coolant flow away from the valve device 150.

[0040] Finally, the second output port 154 of the valve device 150 leads, via a working path line 131 of a working path 130, to a hydraulic actuator, here: to a working chamber 141 of a working cylinder 140. The working cylinder 140 can be part of the hydraulic system 100, or part of the workpiece machining device 1000.

[0041] Therefore, is the valve device 150 in the cooling position, as shown in Fig. As shown in Figure 1, the coolant flow originating from the coolant pump 181 is directed into the cooling path 120.

[0042] In the illustrated embodiment, the working cylinder 140 is provided with a preload element 142, for example a spring, which preloads the working cylinder 140 in one direction such that the actuation of the working cylinder 140 by pumping coolant into the working chamber 141 must occur against the preload provided by the preload element 142. Although only the working cylinder is shown here, the working cylinder 140 could, for example, be a coupling (or part of a coupling) by means of which a tool can be coupled to the workpiece machining device 1000. The preload provided by the preload element 142 can thus ensure that the coupling remains closed and the tool therefore remains firmly connected to the workpiece machining device 1000 when the working cylinder is not actuated.

[0043] In the cooling position of the valve device 150, the working chamber 141 is connected to the coolant tank 180 via the second outlet-side port 154 and the second pump-side port 153 of the valve device 150 and the check valve 171. In the cooling position, the spring force of the preload element 142 acts on any coolant present in the working chamber 141, forcing it out of the working chamber 141. If the check valve 171 is designed with a pressure threshold, this threshold is advantageously chosen to be lower than the pressure exerted on the coolant in the working chamber 141 by the preload element 142.

[0044] When the valve device 150 is set (or switched) to the operating position, the first pump-side port 151 is hydraulically connected to the second outlet-side port 154, and the second pump-side port 153 is connected to the first outlet-side port 152. In this case, the coolant flow from the cooling path 120 is cut off; the coolant in the cooling path 120 can drain into the coolant tank 180 via the second cooling path line 122.

[0045] Simultaneously, in the working position, the second outlet-side connection 154 is connected to the working chamber 141 of the working cylinder 140, so that the pressure in the coolant pushes (or: actuates, or: operates) the working cylinder 140 against the preload force of the preload element 142. In the above example of the coupling for a tool (or: tool coupling), for instance, this could release the coupling between the workpiece machining device 1000 and the tool (e.g., welding torch 1001). For this to happen, the first threshold value of the line path pressure relief valve 183 must be selected such that the coolant pump 181 can build up a pressure in the working path 130 that is high enough to overcome the preload force exerted by the preload element 142.

[0046] As in Fig. As indicated in Figure 1, the valve device 150 and the check valve 171 can be arranged or mounted in a common assembly 190. The valve device 150 and / or the assembly 190 can have a switch, preferably an electric switch, by means of which the valve device 150 can be switched between its two positions. Additionally or alternatively, a manual switch can also be provided and arranged for this purpose.

[0047] The hydraulic system 100 can also include a control device 195 which is configured to send control signals to electrically adjustable components of the hydraulic system 100, for example control signals for setting threshold values ​​on valves, to any electrical actuators, for adjusting valves and / or the like.

[0048] The workpiece processing device 1000 according to an embodiment of the second aspect of the present invention can, in addition to the hydraulic system 100 according to the invention, the welding torch 1001 and the (at least one) robot arm 1002, also comprise further elements, for example each of the in Fig. 1 elements shown. The workpiece processing device 1000 can also have a robot controller into which the control unit 195 can be integrated or vice versa, wherein the robot controller is configured to control the movement of the at least one robot arm 1002.

[0049] Fig. Figure 2 shows a schematic representation of a workpiece processing device 2000 and a hydraulic system 200 according to further embodiments of the present invention. The workpiece processing device 2000 and the hydraulic system 200 differ from their counterparts in Fig. 1 each by the design of the valve device 250 and in the associated arrangement of two check valves 171, 272.

[0050] In the hydraulic system 200, the valve assembly 250 is a 5 / 3 hydraulic valve. Its three valve positions include a cooling position (left in Fig. 2), a working position (right in Fig. 2), and a neutral position (center). In the neutral position, both the three pump-side connections 251, 253, 255 of the valve device 250 and the two outlet-side connections 152, 154 within the valve device 250 are disconnected.

[0051] The first outlet port 152 leads to the cooling path 120 (as does the first outlet port 152 of the hydraulic system 100), and the second outlet port 154 leads to the working path 130 (as does the second outlet port 154 of the hydraulic system 100). In the neutral position, the current position of the working cylinder 140 is maintained, provided no other external forces are acting upon it, while at the same time no new coolant is introduced into the cooling path 120.

[0052] A first pump-side connection 251 is permanently connected to the second branch 162 of the line path 160, a second pump-side connection 253 is connected to the second cooling path line 122 via the already described check valve 171, and a third pump-side connection 255 is also connected to the second cooling path line 122 via another check valve 272.

[0053] In the cooling position, the first pump-side port 251 is connected to the first outlet-side port 152 via the valve assembly 250 to allow coolant to be pumped into the cooling path 120. In the cooling position of the valve assembly 250, the third pump-side port 255, connected to the check valve 272, is also connected to the working path line 131 via the valve assembly 250. In this way, in the cooling position, coolant from the working chamber 141 of the working cylinder 140, driven by the preload force of the preload element 142, can flow back into the coolant tank 180 via the further check valve 272 and the filter 184. The second pump-side port 253 remains disconnected within the valve assembly 250 in the cooling position.

[0054] In the operating position, the first cooling path line 121 is connected by the valve device 250 via the first outlet-side port 152 to the second pump-side port 253, and finally via this to the coolant tank 180. In this way, any overpressure existing in the cooling path 120 can be relieved. In the operating position, the second branch 162 of the line path 160 (and thus the coolant pump 181) is also connected by the valve device 250 to the second outlet-side port 154 and thus to the working path line 131. Therefore, in the operating position, the coolant flow from the coolant pump 181 can be used to actuate the working cylinders 140.

[0055] Fig. Figure 3 shows a schematic representation of a workpiece processing device 3000 and a hydraulic system 300 according to further embodiments of the present invention. The workpiece processing device 3000 and the hydraulic system 300 differ from their counterparts in Fig. 2 by an additional control valve 310, an additional pressure tank 319, a differently designed working path 330 and a differently designed working cylinder 340.

[0056] The control valve 310 has two valve-side ports 311, 313 and two cooling path-side ports 312, 314. The first valve-side port 311 is connected outside the control valve 310 to the second outlet-side port 154 of the valve device 250, with the additional pressure tank 319 also connected in this line between the two ports 311, 154.

[0057] The second valve device-side connection 313 is connected to the second cooling path line 122 via the further check valve 272.

[0058] The first cooling path-side port 312 of the control valve 310 is connected via a second working path line 332 to a second working chamber 342 of the working cylinder 340, and the second cooling path-side port 314 of the control valve 310 is connected via a first working path line 331 to a first working chamber 341 of the working cylinder 340. The control valve 310 can now be used to adjust whether the coolant flow, which only reaches the control valve 310 when the valve device 250 is in the working position, is directed into the second working path line 332 and thus the second working chamber 342, or into the first working path line 331 and thus into the first working chamber 341 of the working cylinder 340. Thus, the control valve 310 can be used to set in which direction the bidirectionally actuated (or: double-acting) working cylinder 340 should be actuated.

[0059] The currently unactivated working chamber 341, 342 can be emptied via the second valve-side connection 313 and the additional check valve 272, so that the working cylinder 340 is not blocked. When the valve assembly 250 is switched to the zero position, a predetermined pressure remains in the working chamber 341, 342 selected for actuation by the control valve 310 (in the pressure tank 319). Fig. 3: the second working chamber 342). The working chamber 341, 342 not selected for actuation empties via the further check valve 272. If the valve device 250 is set to the cooling position or the zero position, the valve device 310 is disconnected from the first pump-side connection 251.

[0060] Naturally, many variations are possible in the specific design of details, for example, the valve devices 150 and 250. As another variation, for instance, the valve device 250 in the hydraulic system 300 can also be implemented as a 4 / 2 valve; in this case, the third pump-side connection 255 can be omitted.

[0061] The pressure tank 319 advantageously contains a volume of air and can replace a preload element in the working cylinder 340. This can be particularly advantageous when the working cylinder 340 is used to hold or grip a particularly heavy load for which a preload element cannot provide the necessary preload force, or only with great difficulty. The compressible air in the pressure tank 319 can easily provide the corresponding preload force. A particularly heavy load might be present, for example, if the working cylinder 340 is intended (among other things, or exclusively) for coupling at least one very heavy tool to the workpiece machining device 3000.

[0062] The assembly group 190 can, as in Fig. Figure 3 shows the assembly comprising, in addition to the valve assembly 250 and the check valves 171 and 272, the control valve 310 and, optionally, the pressure tank 319. The assembly may also include one or more electrical and / or manual switches by means of which the valve assembly 250 and / or the control valve 310 can be set to their respective valve positions. Alternatively or additionally, one or both can be set by means of an electrical actuator. This actuator may, for example, be configured to receive corresponding control signals from the control unit 195.

[0063] Fig. 4 and Fig. Figure 5 shows two further embodiments with regard to the spatial arrangement of individual elements of the hydraulic systems 100; 200; 300 and the workpiece processing devices 1000; 2000; 3000 according to the invention. Specifically, one variant is shown for the workpiece processing device 1000; however, it is understood that the above also applies to the workpiece processing devices 2000; 3000, i.e., that the assembly variants shown there are applicable to any embodiment of the present invention.

[0064] Fig. Figure 4 shows a variant in which the workpiece processing device 1000 is itself a robot welding machine. It includes, by way of example, a welding power source 1, which has a robot interface 2. This interface is connected via a control line 4 to a robot controller 15, allowing control commands to be sent from the welding power source 1 to the robot controller 15 and / or vice versa. As mentioned previously, the robot controller 15 can be integrated into the control unit 195 described earlier, or vice versa. The control unit 195 can also be integrated into the welding power source 1.

[0065] The in Fig. The workpiece processing device 1000 shown in Figure 4 also has a cooling unit 3, which may include, in particular, the coolant tank 180, the coolant pump 181, the motor 182, and the filter 184, as well as parts of the cable path 160. Both the cable path 160 and the power lines leading from the welding power source 1 run in a connecting hose package 9 to the robot arm 1002. In the Fig. In the variant shown in Figure 4, the valve device 150 (or alternatively the valve device 250) or advantageously the entire assembly 190 is arranged on, or integrated into, a wire feed unit 6, which in turn is attached or can be attached to the robot arm 1002.

[0066] A wire spool holder 10 for a wire spool 8 containing welding wire is also connected to the robot arm 1002, for example, to its base. The welding wire is fed from the wire spool 8 via a wire feed hose 7 to the wire feed unit 6, by which it is fed. From the wire feed unit 6, a torch hose assembly 14 carries the welding wire to a welding torch 1001 (or: torch body), which is mounted on the robot arm 1002 via a robot flange 11. The torch hose assembly 14 can also at least partially encompass the cooling path 120, through which – when the valve device 150 is in the cooling position – the welding torch 1001 can be cooled with the coolant.

[0067] The welding torch 1001 is coupled to the robot flange 11 via a working cylinder 140, which can be actuated via the working path 130 (which can also run within the torch hose assembly), for example to detach the welding torch 1001 from the robot arm 1002. A collision box 12 can optionally be arranged between the welding torch 1001 and the robot arm 1002.

[0068] For example, to change the welding torch 1001, the robot control 15 can control the robot arm 1002 into a desired position and then instruct the control device 195 to control the valve device 150, to open the working cylinder 140, in order to then be able to replace the welding torch 1001.

[0069] The robot controller 15 can be implemented as any device capable of performing calculations, and in particular, of executing software, an app, or an algorithm. The robot controller 15 can, for example, include at least one processor unit, such as a central processing unit (CPU), a graphics processing unit (GPU), a field-programmable logic gate (FPGA), an application-specific integrated circuit (ASIC), or a combination thereof. The robot controller 15 can also include a working memory that is operationally coupled to the at least one processor unit, as well as non-volatile memory that is operationally coupled to both the at least one processor unit and the working memory.The robot controller 15 can be implemented wholly or entirely in a local device and / or wholly or entirely in a remote system, such as a remotely located server and / or a cloud computing platform. The same applies to the control unit 195, which, however, is preferably located locally, for example, integrated into the welding power source 1.

[0070] Fig. Figure 5 shows one variant of the structure of Fig. 4, wherein the valve device 150, preferably the entire assembly 190, is arranged on the cooling unit 3 instead of on the robot arm 1002. The line path 160 thus runs within the cooling unit 3, while the cooling path 120 and the working path 130 run at least partially within the connecting hose assembly. The variant according to Fig. In this respect, 4 is therefore more advantageous, since the typically quite long distance between the cooling unit 3 and the robot arm 1002 only has to be covered by the line path and the second cooling path line 122.

[0071] Fig. 4 and Fig. Figure 5 illustrates that a further advantage of the present invention lies in its ease of retrofitting to existing systems. The assembly 190 can be easily integrated into existing fluid systems.

[0072] Fig.Figure 6 shows a schematic flowchart to explain a method according to a further embodiment of the present invention, namely a method for operating a workpiece processing device 1000; 2000; 3000. The method can be carried out using any workpiece processing device 1000; 2000; 3000 and / or any hydraulic system 100; 200; 300 according to the invention, in particular as already explained above. Accordingly, the method can be adapted to all workpiece processing devices and / or hydraulic systems according to the invention, and vice versa. However, the method can also be carried out separately.

[0073] In step S10, a coolant is pumped from a coolant tank 180 by means of a coolant pump 181 to generate a coolant flow.

[0074] In further steps, a valve device 150; 250 is set to one of several valve positions, wherein the valve positions have at least the following: a cooling position whereby the coolant flow is directed into a cooling path 120 for cooling the workpiece machining device 1000; 2000; 3000; and a working position whereby the coolant flow is directed into a working path 130; 330 for hydraulic interaction with an actuator (in particular a working cylinder 140; 340 or a hydraulic motor).

[0075] Accordingly, in step S20 the valve device 150; 250 is set to the cooling position (or: one of several cooling positions), and in step S30 the valve device 150; 250 is set to the working position (or: one of several working positions).

[0076] The valve settings can optionally also include a zero position, in which the coolant flow is directed neither into the cooling path nor into the working path. In an optional step S40, the valve device 150; 250 can thus be set to the zero position.

[0077] In some variants, the workpiece machining device 1000, 2000, or 3000 can be used to machine a workpiece simultaneously with the pumping of the coolant (S10) and the adjustment of the valve device 150 or 250 (S20-S40). In other words, the process can include a step (S50) in which the workpiece is machined using the workpiece machining device 1000, 2000, or 3000, and which optionally partially or completely overlaps (or includes) step S10, step S20, step S30, and / or step S40. Each of the steps S20, S30, and S40 can be performed once or multiple times.

[0078] The procedure can also include a step S60 in which a control valve 310 is set to determine which of two working chambers 341, 342 of a working cylinder 340 is to be actuated. Reference symbol list 1 welding power source 2 Robot interface 3 cooling units 4 control lines 6 wire feed unit 7 Wire conveyor hose 8 wire coils 9 Connection hose package 10 wire spool holder 11 Robot flange 12 collision boxes 14 Burner hose package 15 Robot Control 100 hydraulic system 120 Cooling path 121 first cooling path line 122 second cooling path line 130 work path 131 Work path management 140 working cylinders 141 Chamber of Labour 142 Preload element 150 valve device 151 first pump-side connection 152 first output connection 153 second pump-side connection 154 second output side connection 160 conduit path 161 first branch 162 second branch 171 Check valve 180 coolant tank 181 Coolant pump 182 Engine 183 Line path pressure relief valve 184 filters 190 assembly 195 Control unit 200 hydraulic system 250 valve device 251 first pump-side connection 253 second pump-side connection 255 third pump-side connection 272 Check valve 300 hydraulic system 310 Control valve 311 First valve device-side connection 312 first cooling path side connection 313 second valve device-side connection 314 second cooling path side connection 319 Pressure tank 330 work path 331 first work path line 332 second work path line 340 working cylinders 341 first Chamber of Labor 342 second chamber of labor 1000 workpiece processing machine 1001 welding torches 1002 robot arm 2000 workpiece machining equipment 3000 workpiece processing machine S10..S60 Procedure steps

Claims

[1] Hydraulic system (300) for a workpiece machining device (1000; 2000; 3000), comprising: a valve device (150; 250) which is switchable between at least one cooling position and at least one working position, wherein in the cooling position, a coolant flow originating from a coolant pump (181) is directed by the valve device (150; 250) into a cooling path (120) for cooling the workpiece processing device (1000; 2000; 3000), and wherein, in the operating position, the coolant flow is directed by the valve device (150; 250) for hydraulic interaction with at least one actuator (140; 340); and a control valve (310) which is hydraulically arranged between the valve device (250) and the hydraulic actuator (340), and by means of which it is adjustable: - which of at least two working chambers (341, 342) of the hydraulic actuator (340) is hydraulically connected to the coolant pump (181) or - which of at least two hydraulic actuators is hydraulically connected to the coolant pump (181), when the valve device (250) is in the working position. [2] Hydraulic system (300) according to claim 1, further comprising the at least one actuator (140; 340), wherein the actuator (140; 340) is a hydraulic working cylinder, and wherein the hydraulic interaction in the working position preferably actuates the hydraulic working cylinder against a preload. [3] Hydraulic system (300) according to claim 1 or 2, wherein the valve device (250) can also be switched to a zero position in which the The coolant pump (181) is not hydraulically connected to either the cooling path (120) or the hydraulic actuator (140; 340). [4] Hydraulic system (300) according to one of claims 1 to 3, wherein a pressure tank (319) is connected between the control valve (310) and the valve device (250). [5] Hydraulic system (300) according to one of claims 1 to 4, wherein the valve device can additionally be switched into a further working position in which the coolant flow is directed by the valve device to a further hydraulic interaction with the actuator or to a hydraulic interaction with a further actuator, wherein the hydraulic interaction and the further hydraulic interaction with the actuator or the interaction with the actuator and the interaction with the further actuator are in particular opposite directions. [6] Hydraulic system (300) according to any one of claims 1 to 5, wherein the workpiece processing device (1000; 2000; 3000) is a robotic workpiece processing device, for example a welding device. [7] Workpiece processing device (1000; 2000; 3000) comprising the hydraulic system (100; 200; 300) according to any one of claims 1 to 6. [8] Method for operating a workpiece processing device (1000; 2000; 3000), comprising at least the steps: Pumping (S10) a coolant from a coolant tank (180) by means of a coolant pump (181) to generate a coolant flow; Setting (S20) a valve device (150; 250) to at least one cooling position, thereby directing the coolant flow into a cooling path (120) for cooling the workpiece machining device (1000; 2000; 3000); Setting (S30) the valve device (150; 250) to at least one working position, thereby directing the coolant flow into a working path (130; 330) for hydraulic interaction with an actuator (140; 340); and Adjustment (S60) of a control valve (310) which is hydraulically arranged between the valve device (250) and the hydraulic actuator (340) in order to adjust - which of at least two working chambers (341, 342) of the hydraulic actuator (340) is hydraulically connected to the coolant pump (181) or - which of at least two hydraulic actuators is hydraulically connected to the coolant pump (181), when the valve device (250) is in the working position. [9] Method according to claim 8, wherein the workpiece is simultaneously pumped (S10) of the coolant and adjusted (S20) of the valve device (150; 250). A machining device (1000; 2000; 3000) is used to machine a workpiece (S30).

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