Working mechanism for performing a working process and method for operating a working mechanism

Abstract

The invention relates to a working mechanism having a machine housing, which is provided with a housing recess having a movable closure flap, having a compressed-air drive for moving the closure flap and having an actuating control for the selective ventilation or venting of at least two working chambers of the compressed-air drive, wherein a first valve assembly is provided with a first pressure sensor for detecting the first fluid pressure in the first working chamber and wherein a second valve assembly is provided with a second pressure sensor for detecting the second fluid pressure in the second working chamber, wherein the actuating control comprises a processing mechanism which is configured for processing the sensor signals of the pressure sensors and which is configured for providing a control signal for the first valve assembly to accelerate the working piston in the direction of the second end position and for the second valve assembly to brake the working piston before reaching the second end position.

Description

Technical Field

[0001] The present invention relates to a working mechanism for performing a work process and a method for operating such a working mechanism. Background Technology

[0002] According to prior art known to the applicant but not documented in printed literature, the working mechanism of a machine tool, such as a milling machine, has a machine housing with a door at its front through which a workpiece can be transported into a workspace defined by the machine housing. Typically, the door is opened before the machining process begins to supply a new workpiece to the workspace and then remains closed until the machining process is completed. After the machining process ends, the door is reopened to remove the finished workpiece. Furthermore, a housing recess can be provided in the machine housing, configured to supply tools to and from the workspace, and the housing recess can be closed by means of a closing valve. Typically, multiple tool changes occur during the machining process of a workpiece, thus requiring the closing valve to be opened and closed multiple times. It is possible to interrupt the machining process when the closing valve is opened to, for example, prevent undesirable leakage of cooling lubricant from the workspace into the surrounding environment, as is possible when the machining process continues despite the closing valve being open. The movement of the closing valve is actuated, for example, by means of an electric variable-speed motor with a flanged lead screw, by which the rotational motion of the variable-speed motor can be converted into linear motion for the closing valve. Summary of the Invention

[0003] The objective of this invention is to provide a working mechanism and a method for operating such a working mechanism, by means of which the processing of workpieces can be made more efficient.

[0004] The task described above is solved by means of the features of claim 1 for a working mechanism of the type mentioned at the beginning. Here, the working mechanism includes a machine housing defining a workspace and having a housing recess with a closing valve movable between an open and closed position, and a working unit housed within the workspace and configured for processing and / or handling work objects, and a compressed air actuator configured to actuate the closing valve and having an actuator housing with a working recess in which a working piston movably accommodated between a first and a second terminal position is arranged, the working piston dividing the working recess into a first working chamber and a second working chamber of variable size, wherein the compressed air actuator is equipped with an actuation control unit including a first valve assembly for the first working chamber. The optional ventilation or exhaust and the second valve assembly for optional ventilation or exhaust of the second working chamber, wherein the first valve assembly is equipped with a first pressure sensor for detecting a first fluid pressure in the first working chamber and wherein the second valve assembly is equipped with a second pressure sensor for detecting a second fluid pressure in the second working chamber, wherein the actuation control unit includes a processing mechanism configured to process a first sensor signal from the first pressure sensor and a second sensor signal from the second pressure sensor, and to provide a first control signal to the first valve assembly and a second control signal to the second valve assembly, wherein the processing mechanism is configured to provide a first control signal for the first valve assembly to accelerate the working piston in a direction toward a second end position and to provide a second control signal for the second valve assembly to brake the working piston before reaching the second end position.

[0005] By applying a compressed air actuator that can be optionally configured to provide oscillating or linear motion, a high-dynamic-force relative motion of the closing valve to the machine housing is achieved. Preferably, the opening and closing processes for the closing valve are executed more quickly compared to currently used drive technologies. This reduces downtime, which is necessary for tool changes and is significantly determined by the duration of the opening and subsequent closing processes of the closing valve. This results in a reduction in the overall machining time for the workpiece and, consequently, an increase in the efficiency of the working mechanism, under the assumption that machining the workpiece requires numerous tool changes.

[0006] To ensure the advantageous use of the compressed air actuator, it is advantageous to construct the compressed air actuator as a double-acting actuator, as this allows for the provision of a combination of driving and braking forces as needed. In this case, the compressed air actuator has a working piston movably accommodated in a working recess, which, together with the working recess, defines a first working chamber and a second working chamber of variable size. Here, not only the first working chamber but also the second working chamber can be optionally supplied with compressed air during the scavenging process or undergo depressurization during the exhaust process via an associated first or second valve assembly. Preferably, the working piston is arranged such that, during the movement of the closing valve from the open position to the closed position, it follows a movement path that begins at a first terminal position and ends at a second terminal position. Here, the actuator housing, the working recess, and the working piston are coordinated with each other such that scavenging and exhaust of not only the first working chamber but also the second working chamber are always achieved, regardless of the position of the working piston along the movement path.

[0007] To provide compressed air to at least one of the two working chambers of the compressed air actuator and to exhaust air from at least one of the two working chambers, the compressed air actuator is equipped with an actuation control unit, which can be configured in particular as a valve platform having a first valve assembly configured for ventilation and exhaust of the first working chamber, and a second valve assembly configured for ventilation and exhaust of the second working chamber. Purely exemplary, each of the valve assemblies includes a ventilation valve configured as a 2 / 2 directional valve and an exhaust valve configured as a 2 / 2 directional valve, wherein the ventilation valve and the exhaust valve are electrically actuated and are in particular configured as piezoelectric valves.

[0008] In order to perform precise ventilation and exhaust of the corresponding working chamber, each valve assembly is equipped with a pressure sensor, by means of which the fluid pressure in the corresponding working chamber or in the supply line corresponding to the corresponding working chamber is measured.

[0009] Furthermore, the actuation control unit includes a processing mechanism, which is particularly configured as a microcontroller or microprocessor and is configured to process the electrical signal levels of the first and second pressure sensors and to provide control signals to the corresponding valve assemblies. Additionally, the processing mechanism can be configured to include a communication interface, particularly a bus interface, for communication with a higher-level control unit, particularly a machine control unit for the working mechanism. Thus, through the communication interface, control commands from the higher-level control unit can be provided to the processing mechanism of the actuation control unit, and status signals and / or diagnostic signals of the processing mechanism can be communicated to the higher-level control unit.

[0010] In order to ensure the effective execution of the opening and closing processes of the closing valve, the processing mechanism is configured to provide control signals for the first valve assembly and the second valve assembly, by means of which the working piston and the closing valve coupled thereto are rapidly accelerated and subsequently braked.

[0011] By way of example, the processing mechanism provides a first control signal to a first valve assembly in a first step, which causes the actuation of the septic valve of the first valve assembly to cause septic gas exchange in the first working chamber of the compressed air drive. In parallel, the processing mechanism can provide a first control signal to a second valve assembly to cause the actuation of the exhaust valve of the second valve assembly, thereby allowing air to flow out of a second working chamber, which is reduced in size during the movement of the working piston between a first and a second end position.

[0012] In the second step, a second control signal for the second valve assembly is provided, wherein in each case, the second control signal causes the closure of the exhaust valve for the second valve assembly. Furthermore, it can be configured that the second control signal also causes the opening of the sump valve of the second valve assembly to allow compressed air to be supplied to the second working chamber and thereby enhance the braking action for the working piston. Supportively, it can be configured that, along with the provision of the second control signal for the second valve assembly, the processing mechanism also provides a second control signal for the first valve assembly, which is at least intended to prevent further compressed air supply to the first working chamber by closing the first sump valve. Additionally, it can be further configured that, by means of the control signal for the first valve assembly, the opening of the first exhaust valve is also caused to support the braking process for the working piston.

[0013] Advantageous improvements of the invention are the subject of the dependent claims.

[0014] Preferably, the compressed air actuator is constructed as a pneumatic cylinder with a working piston connected to a piston rod that passes through the actuator housing at its end, wherein the actuator housing is connected to the machine housing and the piston rod is connected to a sealing valve, or wherein the actuator housing is connected to the sealing valve and the piston rod is connected to the machine housing. This ensures a compact structure for the compressed air actuator and the feasibility of compactly integrating the compressed air actuator into the machine housing.

[0015] Advantageously, the closing valve can be linearly supported at the machine housing. Particularly preferably, the closing valve is configured to move parallel to a surface of the machine housing, which also has a housing recess that should be closed by the closing valve. It is not important here whether the movement of the closing valve is horizontal, vertical, or at an angle to the vertical.

[0016] In an improved embodiment of the invention, the compressed air actuator, particularly a compressed air actuator configured as a pneumatic cylinder, is equipped with a position sensor assembly configured to provide position signals. The position sensor assembly includes a first terminal position sensor disposed in the region of a first terminal position of the working piston, and a second terminal position sensor disposed in the region of a second terminal position of the working piston and electrically connected to the processing mechanism. With this position sensor assembly, it is possible to determine, based on the electrical signals from the respective terminal position sensors, whether the working piston has moved from one terminal position to another as desired, and whether it has actually reached that other terminal position. This information is particularly useful for incorporating other work processes into the machine, such as tool changing in the case of an open closed valve or continuation of workpiece processing in the case of a closed closed valve, to ensure the desired efficient operation of the machine. Exemplarily, the first and second terminal position sensors are configured as a switching mechanism, which outputs an on signal when the working piston is positioned in a preset position relative to the respective terminal position sensor. Alternatively, the first and second terminal position sensors can be configured to detect the position of a segment of the movement path of the working piston, thereby enabling an evaluation of whether the working piston has reached the corresponding terminal position within the respective terminal position sensor or in the processing mechanism.

[0017] In another embodiment of the invention, the compressed air actuator, particularly a compressed air actuator configured as a pneumatic cylinder, is equipped with a position sensor assembly configured to provide a position signal. The position sensor assembly includes a position sensor extending in the region between a first end position and a second end position of the working piston, and is configured to detect the position of the working piston between the first and second end positions. This position sensor allows the position of the working piston along the entire movement path between the first and second end positions to be determined. Accordingly, at each point in time during operation of the mechanism, the position information provided by the position sensor is used by the processing mechanism and can be used to control the first and second valve assemblies. The position sensor can also be formed by multiple individual sensors arranged in rows, partially overlapping if necessary, along the movement path.

[0018] Preferably, the processing mechanism is configured to have a communication interface for communicating with a higher-level control mechanism, and the processing mechanism is arranged such that when the working piston approaches a first or second terminal position, a start signal is provided to the communication interface based on a position signal from a position sensor assembly. By providing the start signal, when the closing valve has at least nearly reached the desired terminal position, other functional components of the working mechanism, such as a tool changer, rotating head, or milling head, can be prepared for the subsequent action.

[0019] Advantageously, the processing mechanism is configured such that when the working piston approaches the first or second end position, a braking signal is provided to the first and second valve assemblies based on the position signal from the position sensor assembly, thereby actuating the braking of the closing valve by means of a compressed air actuator. This use of the position signal from the position sensor assembly results in high reproducibility for the opening and closing movements of the closing valve, because very reliable position determination of the working piston can be performed based on the position signal.

[0020] In an improved embodiment of the invention, an interface for coupling with a tool magazine is constructed at a first wall section of the machine housing, and a closing valve is associated with the first wall section and configured to release and close a housing recess for tool replacement openings. The tool magazine can, for example, involve a kittenmagazin, mounted adjacent to the working mechanism and adjacent to the first wall section of the machine housing, and the kittenmagazin facilitates the replacement of production tools, such as milling cutters or turning tools, by means of a double-hook gripper, the production tools being provided at a housing recess for delivery into or out of the working space of the machine housing.

[0021] Preferably, the processing mechanism stores the theoretical pressure trend of the pressure signal from the first pressure sensor during ventilation in the first working chamber, and the processing mechanism is configured to measure the deviation between the theoretical pressure trend and the pressure signal from the first pressure sensor during ventilation in the first working chamber, and to output a fault signal when the deviation exceeds a preset value. This allows for the determination of changes in the movement dynamics of the closing valve, which can be caused, for example, by wear of the compressed air actuator or the guide device for the closing valve, or by contamination at the guide device. Based on the fault signal, the operator of the mechanism can identify a possible impending malfunction in the movement of the closing valve and implement appropriate countermeasures. For example, the value for the deviation can be selected such that the fault signal is output even with a small change in the actual trend of the pressure signal from the first pressure sensor, so as to notify the operator of the mechanism that preventative maintenance should be performed before damage to the closing valve, the guide device for the closing valve, or the compressed air actuator occurs, possibly due to further development of changes caused by wear.

[0022] Suitablely, the processing mechanism is configured such that a fault signal is output when the pressure signal of the first pressure sensor fluctuates with a preset frequency and / or a preset amplitude during ventilation in the first working chamber, and / or when the deviation between the movement duration of the working piston between the first and second end positions and a preset movement duration exceeds a preset value, particularly when the movement duration is below the preset movement duration extreme value. Oscillations in the pressure signal of the first pressure sensor can occur when the connection between the compressed air actuator and the closing valve is damaged or completely failed. To output a fault signal in this situation, the processing mechanism is configured to analyze the temporal trajectory of the pressure signal of the first pressure sensor. Specifically, a comparison is performed between the oscillation frequency of the possible pressure fluctuation and the spectrum of permissible and impermissible oscillation frequencies stored in the processing mechanism. Additionally or alternatively, the oscillation amplitude of the occurring pressure fluctuation is compared with extreme values ​​or multiple extreme values ​​stored in the processing mechanism for different oscillation frequencies. Alternatively or supplementarily, the processing mechanism can be configured to measure the deviation between the travel duration of the working piston between the first and second end positions and a preset travel duration, and output a fault signal when the deviation exceeds a preset value. Preferably, the fault signal is output when the travel duration is lower than the preset travel duration extreme value.

[0023] The object of the present invention is achieved by a method for operating the working mechanism according to the invention, the method comprising the steps of: providing a first ventilation signal to a first valve assembly and ventilating the first working chamber by a processing mechanism; providing a first exhaust signal to a second valve assembly and exhausting the second working chamber by a processing mechanism; measuring a first pressure direction of a first fluid pressure and / or measuring a second pressure direction of a second fluid pressure; and providing a first shut-off signal to the first valve assembly to terminate the ventilation of the first working chamber and providing a second shut-off signal to the second valve assembly to terminate the exhaust of the second working chamber by a processing mechanism, wherein, during the provision of the first ventilation signal, at least one diagnostic function from the group consisting of: linear guide diagnosis, closed valve diagnosis, and closed valve position diagnosis is performed according to the first pressure direction and / or according to the second pressure direction.

[0024] Advantageously, for the diagnosis of the linear guide section, the deviation between the pressure value of the first pressure direction and the stored pressure value of the first pressure direction is measured, and when the value of the deviation exceeds the maximum value that can be preset, the processing mechanism outputs a diagnostic signal.

[0025] Preferably, the system is configured such that a first change value for a first pressure direction is compared with a preset first extreme value and / or a second change value for a second pressure direction is compared with a preset second extreme value, and a diagnostic signal is output by the processing mechanism when the first change value exceeds the first extreme value and / or the second change value exceeds the second extreme value. In the case of a closed valve diagnosis, the objective is to determine possible damage to the connection between the compressed air actuator and the closed valve. In the case of such damage, it is particularly possible to start from the faster movement of the compressed air actuator, since the mass of the closed valve does not necessarily move with it. Accordingly, for closed valve diagnosis, the system determines whether the first pressure signal has a trend based on changes in the first pressure signal, such as the derivative of the first pressure signal with respect to time, from which a faulty connection between the compressed air actuator and the closed valve can be inferred. Similarly, the second pressure signal can be considered supplementarily or alternatively. The output of the fault signal is configured such that the corresponding change value is compared with a preset first or second extreme value, and a diagnostic signal is output when the corresponding extreme value is exceeded.

[0026] In another design of the method, for diagnosing a closed valve, the position signal of the position sensor assembly is evaluated to determine the duration of movement of the working piston between a first and second end position. A diagnostic signal is output by the processing mechanism when the duration of movement exceeds a preset deviation from a preset duration, particularly when the duration of movement is below a preset extreme value. This method can be implemented not only when the compressed air drive is equipped with an end position sensor but also when the compressed air drive is equipped with a position sensor, because in both cases, at least the duration of movement for the closed valve between the first and second end positions (or vice versa) can be determined. When a position sensor is used, a portion of the movement path of the closed valve can also be considered regarding the necessary duration of movement. The duration of movement (which can also be referred to as the actual duration) is compared with a preset duration of movement in the processing mechanism, and a diagnostic signal is output when the deviation between the measured duration of movement and the preset duration of movement, particularly the duration stored in the processing mechanism, exceeds a preset deviation. Preferably, the movement duration is compared with the extreme value of the movement duration in the processing mechanism, and a diagnostic signal is output when the movement duration is lower than the extreme value of the movement duration.

[0027] In an improved version of the method, for closure valve diagnosis, the first pressure trend is evaluated regarding fluctuations with a preset frequency and / or a preset amplitude, and a diagnostic signal is output by the processing unit when a fluctuation occurs within a preset frequency range and / or has a preset minimum amplitude. Fluctuations occur in the first pressure trend when pressure regulation is used for the ventilation of the compressed air actuator, and the regulator implemented for this purpose, due to its regulation characteristics set for the normal operation of the closure valve, attempts to reach the desired actual value for the first pressure with at least significant ineffectiveness when there is wear or damage to the closure valve and / or the compressed air actuator. These fluctuations can be examined regarding their frequency and / or amplitude so that wear or damage can be inferred. Attached Figure Description

[0028] Advantageous embodiments of the invention are shown in the accompanying drawings. Herein:

[0029] Figure 1 A strictly schematic side view is shown of the working mechanism, which includes a machine housing, a housing recess with an associated closed valve, a compressed air actuator, and an actuation control unit.

[0030] Figure 2 Showing according to Figure 1 A schematic diagram of the actuation control unit.

[0031] Figure 3 A strictly schematic diagram showing the signals for different position sensors, and

[0032] Figure 4 A strictly schematic diagram showing the pressure flow in a compressed air actuator. Detailed Implementation

[0033] exist Figure 1The working mechanism 1, shown schematically, is exemplarily constructed as a milling machine and includes a square machine housing 2. An interface 4, shown only schematically, is constructed on a side wall 3 of the machine housing 2, oriented only vertically. This interface is configured to connect to a tool magazine, such as a chain magazine, not shown in further detail. Furthermore, a housing recess 5, exemplarily constructed at right angles, is provided on the side wall 3, passing through the side wall 3 and thereby establishing a connection between the working space 6, defined by the edge of the machine housing 2, and the surrounding environment of the working mechanism 1. Exemplarily, tools (not shown in further detail) can be allowed to enter or be removed from the working space 6 via the housing recess 5, wherein the tools can be used by a milling machine (not shown) housed in the working space 6 to process workpieces (also not shown) and can be housed in a tool magazine (also not shown) outside the working space 6.

[0034] A closing valve 7 is linearly movable at side wall 3, the closing valve being movable along a movement path 15 between an open position and a closed position, in which a housing recess 5 is released and in which a housing recess 5 is closed. By way of example, two horizontally extending guide rails 8, 9 are provided for supporting the closing valve 7, the guide rails being fixed at side wall 3 and configured, for example, as rod guides for the closing valve 7 (not shown in more detail). Furthermore, the closing valve 7 is associated with a compressed air actuator 10, the compressed air actuator being configured to provide an adjustment force to the closing valve 7. By way of example, the compressed air actuator 10 relates to a pneumatic cylinder having an actuator housing 16 extending along the movement path 15, in which a working recess 17 is constructed, the working recess also referred to as a cylinder bore. A working piston 18 is linearly and sealingly housed within a working recess 17, dividing the recess 17 into a first working chamber 19 and a second working chamber 20 of variable size. Furthermore, the working piston 18 is coupled to a piston rod 21, which passes through the actuator housing 16 at its end and is connected to a coupling member 22, which is itself fixed to the closing valve 7. Because the actuator housing 16 is fixed to the side wall 3 in a manner not shown in more detail, the linear relative movement of the working piston 18 and the piston rod 21 to which it is connected causes a linear relative movement of the closing valve 7 relative to the machine housing 2.

[0035] To provide adjustment force via the compressed air actuator 10, the first working chamber 19 is connected to the actuation control unit 30 via a first fluid line 23, which then engages... Figure 2A more detailed description follows. Furthermore, the second working chamber 20 is connected to the actuation control unit 30 via a second fluid line 24.

[0036] By way of example only, the compressed air actuator 10 is equipped with a position sensor assembly 25, which includes a first terminal position sensor 26 and a second terminal position sensor 27. The first and second terminal position sensors are respectively disposed at the end regions of the actuator housing 16 and configured to detect the presence or absence of the working piston 18. Here, the first terminal position sensor 26 is connected to the actuation control unit 30 via a first sensor line 28. Furthermore, the second terminal position sensor 27 is connected to the actuation control unit 30 via a second sensor line 29.

[0037] according to Figure 1 The diagram shows a switching box 11 arranged laterally adjacent to the machine housing 2. A machine control unit for the working mechanism 1, not shown in more detail, is housed within the switching box. This machine control unit may include, for example, a programmable control unit (SPS) configured to coordinate all processes that can be performed by the working mechanism. The machine control unit also coordinates workpiece machining with necessary tool changes, which are accompanied by the operation of a closing valve 7. Exemplarily, an actuation control unit 30 is connected to the switching box 11 via a communication line 12.

[0038] If it is possible to Figure 2 As shown in the purely schematic illustration, the actuation control unit 30 includes a valve system 31 and an associated processing mechanism 32. Exemplarily, the processing mechanism 32 is configured as a microprocessor and is electrically connected to the valve 37 of the valve system 31 via control lines 33, 34, 35, and 36. Furthermore, a plurality of sensor lines 41, 42, 43, and 44 are connected to the processing mechanism 32, wherein the sensor lines 41... Figure 1 The sensor line 28 shown is connected to the first terminal position sensor 26 and the sensor line 42 is connected via... Figure 1 The sensor line 29 shown is connected to the second terminal position sensor 27. Furthermore, the first pressure sensor 45 is connected to the processing mechanism 32 via sensor line 43, and the second pressure sensor 46 is connected to the processing mechanism 32 via sensor line 44. The processing mechanism 32 is electrically connected to a communication interface 57 via an internal communication line 56, which is configured to connect to the communication line 12 and thereby enable communication between the processing mechanism 32 and the components housed in the switching box 11.

[0039] Valves 37 and 39 form a first valve assembly 48, which is connected to a first fluid connection 52 via a first fluid line 50, wherein the first fluid connection 52 is based on... Figure 1 The diagram shows the connection between the first fluid line 23 and the first working chamber 19. Valves 38 and 40 form a second valve assembly 49, which is connected to a second fluid connection 52 via a second fluid line 51, wherein the second fluid connection 52 is based on... Figure 1 The diagram shows that the second fluid line 24 connects to the second working chamber 20.

[0040] Furthermore, valves 37 and 38 are connected to a fluid source 54, typically arranged outside the actuation control unit 30, which is only schematically shown. Valves 39 and 40 are connected to a fluid outlet, which is particularly equipped with a silencer 55. Purely exemplary, valves 37 to 40 are all configured as 2 / 2 directional valves, wherein valves 37 to 40 are configured according to... Figure 2 The diagram shows a solenoid valve, but in practice it can often be constructed as a piezoelectric valve.

[0041] If it is possible to Figure 2 As determined in the previous analysis, the first pressure sensor 45 is positioned at the first fluid line 50, thereby enabling the measurement of the fluid pressure present in the first working chamber 19. The second pressure sensor 46 is positioned at the second fluid line 51, thereby enabling the measurement of the fluid pressure present in the second working chamber 20.

[0042] When the working mechanism 1 is in operation, it is configured such that only one of the corresponding two valves 37 to 40 of the corresponding valve assemblies 48 and 49 is opened, while the other valve 37 to 40 of the corresponding valve assemblies 48 and 49 is closed. This allows for simultaneous ventilation of the two working chambers 19 and 20 of the compressed air actuator 10, for example, by opening valves 37 and 38 while closing valves 39 and 40. Furthermore, it allows for simultaneous exhaust of the two working chambers 19 and 20 of the compressed air actuator 10, for example, by opening valves 39 and 40 while closing valves 37 and 38. Typically, ventilation of one working chamber 19 or 20 is performed in parallel with exhaust of the corresponding other working chamber 19 or 20 by correspondingly opening the associated valves 37 and 39 or 38 and 40.

[0043] At least one program, i.e., a series of instructions, is stored in the processing mechanism 32, which, by means of the electrical signals from the two terminal position sensors 26 and 27 and the two pressure sensors 45 and 46, can control valves 37 to 40 to perform a movement for closing valve 7. The program stored in the processing mechanism 32 specifically enables coordinated control of valves 37 to 40 to achieve high kinetic power for the movement of closing valve 7. This high kinetic power is caused, in particular, by a strong pressure difference between the first working chamber 19 and the second working chamber 20, and includes not only high acceleration for closing valve 7 but also strong braking, which can be achieved through proper ventilation and exhaust in the two working chambers 19 and 20.

[0044] exist Figure 3 The strictly schematic diagram shows the signal flow for terminal position sensors 26 and 27, and for a position sensor (not shown) that can be used alternatively to terminal position sensors 26 and 27, wherein the position sensor extends along the motion path 15 along the actuator housing 16 and achieves the determination of the position of the working piston 18 along the entire motion path 15. Purely exemplary, it is based on the placement of a permanent magnet (not shown in more detail) at the working piston 18 and the configuration of the two terminal position sensors 26, 27 and the position sensor (not shown) for detecting the field strength of the magnetic field provided by the permanent magnet, thereby enabling the detection of the position of the working piston 18 at least for a segment of the motion path 15 when using terminal position sensors 26, 27, or enabling the complete detection of the position of the working piston 18 when using position sensors.

[0045] If it is possible to Figure 3 As derived from this, the position sensor generates a position signal 60, which is related to the working piston 18 and... Figure 1 The spacing of the first terminal positions 13 shown is proportional. Correspondingly, the detection range of the position sensor extends across the entire length of the motion path 15. In contrast, the two terminal position sensors 26 and 27 are only configured to detect portions of the motion path 15. Here, the first terminal position sensor 26 is positioned at the actuator housing 16 such that it can detect the working piston 18 as long as the working piston is in the region of the first terminal position 13. The second terminal position sensor 27 is positioned at the actuator housing 16 such that it can detect the working piston 18 as long as the working piston is in the region of the second terminal position 14.

[0046] Exemplarily, the first end position sensor 26 provides a constant signal level 61 when the working piston 18 is positioned in the first end position 13 and when there is a small gap between the working piston 18 and the first end position 13. This signal level then decreases linearly with increasing gap between the working piston 18 and the first end position 13 and disappears with further increasing gap. In contrast, the second end position sensor 26 does not provide a signal level 62 as long as the working piston 18 is positioned in the region of the first end position 13. Only when the working piston 18 approaches the second end position 14 does the signal level 62 rise linearly to a maximum value, which then remains constant until the working piston 18 reaches the second end position 14.

[0047] exist Figure 4 The diagram illustrates, strictly schematically and purely demonstratively, a first pressure path p1 for pressure in the first working chamber 19 and a second pressure path p2 for pressure in the second working chamber 20, the first and second pressure paths being capable of performing operations according to... Figure 1 This occurs during the closing process of the closed valve 7. For Figure 4 The subsequent description begins with the following: the closing valve 7 is first arranged in the open position, and with it, the working piston 18 is arranged in the first terminal position 13.

[0048] At time point t1, the processing unit 32 provides a ventilation signal to the first valve assembly 48 and an exhaust signal to the second valve assembly 49. The ventilation signal for the first valve assembly 48 causes... Figure 2 The opening of valve 37, as shown, establishes a fluid connection between fluid source 54 and the first working chamber 19. An exhaust signal for the second valve assembly 59 causes... Figure 2 The opening of valve 39, as shown, thereby releasing the fluid communication connection between the second working chamber 20 and the silencer 55. By opening valve 37, according to... Figure 4 As illustrated, the first pressure p1 initially increases until the pressure on the working piston 18 caused by this pressure increase in the compressed air actuator 10 is so great that the working piston 18, together with the coupled piston rod 21 and the closing valve 7, begins to move from the first end position 13 toward the second end position 14. This movement begins at time t2 and is accompanied by a decrease in the pressure p1 in the first working chamber 19 and an increase in the pressure p2 due to the reduction in the volume of the second working chamber 20.

[0049] From time point t3, the acceleration phase ends for the closing valve 7, and the working piston 18, the piston rod 21 connected to it, and the closing valve 7 undergo the same type of movement until time point t4. At time point t4, the closing valve 7 has almost reached the closed position, and braking is introduced for the closing valve 7 and the working piston 18 to avoid collisions in the closed position and to avoid collisions in the second end position 14 of the working piston 18. For this purpose, a closing signal is provided to valve 37 of the first valve assembly 48 to prevent further supply of compressed air to the first working chamber 19. In addition, a closing signal is provided to valve 39 of the second valve assembly 49 to prevent further venting of the second working chamber 20. Alternatively, it can be optionally configured to provide a venting signal to valve 38 of the second valve assembly 49 to achieve a pressure increase in the second working chamber 20.

[0050] This results in a decrease in the speed of movement for the working piston 18, the piston rod 21 connected thereto, and the closing valve 7. Consequently, a decrease in pressure occurs in the first working chamber 19 from time point t4. Furthermore, a pressure increase occurs in the second working chamber 20 from time point t4 until time point t5, when the working piston 18 has reached the second terminal position 14 and the closing valve 7 completely closes the housing recess 5. From this time point, a pressure force balance exists, with the pressure acting on the working piston 18. For this force balance at the working piston 18 to be necessary, pressure p1 must be greater than pressure p2, because the effective area of ​​the working piston 18 in the first working chamber 19 is smaller due to the lowering of the piston rod 21 and is less than the effective area of ​​the working piston 18 in the second working chamber.

Claims

1. A working mechanism (1) for performing a work process, having a machine housing (2) defining a workspace (6) and having a housing recess (5) with a closing valve (7) movable between an open position and a closed position, the working mechanism having a working unit housed in the workspace (6) and configured for processing and / or handling work objects, the working mechanism having a compressed air actuator (10) configured to move the closing valve (7) and having an actuator housing (16) with a working recess (17) in which a working piston (18) movably accommodated between a first end position and a second end position is arranged, the working piston dividing the working recess (17) into a first working chamber (19) of variable size and a second working chamber (20) of variable size, wherein, The compressed air actuator (10) is equipped with an actuation control unit (30), which includes a first valve assembly (48) for optional ventilation or venting of the first working chamber (19) and a second valve assembly (49) for optional ventilation or venting of the second working chamber (20). The first valve assembly (48) is equipped with a first pressure sensor (45) for detecting a first fluid pressure in the first working chamber (19), and the second valve assembly (49) is equipped with a second pressure sensor (46) for detecting a second fluid pressure in the second working chamber (20). The actuation control unit (30) includes a processing mechanism (32) configured to process a first sensor signal from the first pressure sensor (45) and a second sensor signal from the second pressure sensor (46), and to provide a first control signal to the first valve assembly (48) and a second control signal to the second valve assembly (49). The processing mechanism (32) is configured to provide a first control signal for the first valve assembly (48) to accelerate the working piston (18) in a direction toward the second terminal position (14) and to provide a second control signal for the second valve assembly (49) to brake the working piston (18) before reaching the second terminal position (14). The compressed air drive (10) is associated with a position sensor assembly configured to provide a position signal and includes a first terminal position sensor (26) disposed in the region of the first terminal position (13) of the working piston (18), and includes a second terminal position sensor (27) disposed in the region of the second terminal position (14) of the working piston (18) and electrically connected to the processing mechanism (32).

2. The working mechanism (1) according to claim 1, characterized in that, The compressed air actuator (10) is configured as a pneumatic cylinder and the working piston (18) is connected to the piston rod (21), the piston rod passing through the actuator housing (16) at its end, wherein the actuator housing (16) is connected to the machine housing (2) and the piston rod (21) is connected to the closing valve (7) or wherein the actuator housing (16) is connected to the closing valve (7) and the piston rod (21) is connected to the machine housing (2).

3. The working mechanism (1) according to claim 2, characterized in that, The closed valve (7) is supported linearly on the machine housing (2).

4. The working mechanism (1) according to claim 2, characterized in that, The position sensor assembly includes a position sensor that extends in the region between a first end position (13) for the working piston (18) and a second end position (14) for the working piston (18) and the position sensor is configured to detect the position of the working piston (18) between the first end position (13) and the second end position (14).

5. The working mechanism (1) according to claim 1 or 4, characterized in that, The processing mechanism (32) has a communication interface (57) configured to communicate with the control mechanism (11) at the next higher level, and the processing mechanism (32) is configured such that when the working piston (18) approaches the first terminal position (13) or the second terminal position (14), a start signal is provided at the communication interface based on the position signal of the position sensor assembly.

6. The working mechanism (1) according to claim 1 or 4, characterized in that, The processing mechanism (32) is configured such that when the working piston (18) approaches the first terminal position (13) or the second terminal position (14), it provides a braking signal to the first valve assembly (48) and the second valve assembly (49) based on the position signal of the position sensor assembly, so as to cause the braking of the closing valve (7) by means of the compressed air actuator (10).

7. The working mechanism (1) according to any one of claims 1 to 4, characterized in that, An interface (4) for coupling with a tool magazine is provided at the first wall section (3) of the machine housing (2), and the closing valve (7) is associated with the first wall section (3) and configured to release and close a housing recess (5) that is configured to provide a tool change opening.

8. The working mechanism (1) according to any one of claims 1 to 4, characterized in that, The processing mechanism (32) stores the theoretical pressure direction of the pressure signal (p1) of the first pressure sensor (45) during ventilation in the first working chamber (19), and the processing mechanism (32) is configured to measure the deviation between the theoretical pressure direction and the pressure signal (p1) of the first pressure sensor (45) during ventilation in the first working chamber (19), and to output a fault signal when the deviation exceeds a preset value.

9. The working mechanism (1) according to any one of claims 1 to 4, characterized in that, The processing mechanism (32) is configured such that when the pressure signal of the first pressure sensor (45) has fluctuations with a preset frequency and / or a preset amplitude during ventilation in the first working chamber (19) and / or when the deviation between the movement duration of the working piston (18) between the first end position (13) and the second end position (14) and the preset movement duration exceeds a preset value, a fault signal is output.

10. The working mechanism (1) according to claim 9, characterized in that, When the movement duration is lower than the preset movement duration limit, a fault signal is output.

11. A method for operating a working mechanism (1) constructed according to any one of claims 1 to 10, comprising the steps of: providing a first ventilation signal to the first valve assembly (48) by the processing mechanism (32) and ventilating the first working chamber (19); providing a first exhaust signal to the second valve assembly (49) by the processing mechanism (32) and exhausting the second working chamber (20); determining a first pressure direction of the first fluid pressure (p1) and / or determining a second pressure direction of the second fluid pressure (p2); and providing a first shut-off signal to the first valve assembly (48) by the processing mechanism (32) to terminate the ventilation of the first working chamber (19) and providing a second shut-off signal to the second valve assembly (49) by the processing mechanism (32) to terminate the exhaust of the second working chamber (20), wherein, During the provision of the first ventilation signal, at least one diagnostic function from the group consisting of the first pressure direction and / or the second pressure direction is performed: linear guide diagnosis, closed valve diagnosis, and closed valve position diagnosis.

12. The method according to claim 11, characterized in that, For the diagnosis of the linear guide section, the deviation between the pressure value in the first pressure direction and the stored pressure value in the first pressure direction is measured, and when the value of the deviation exceeds the maximum value that can be preset, the processing mechanism (32) outputs a diagnostic signal.

13. The method according to claim 11, characterized in that, For the closed valve diagnosis, the first change value used for the first pressure direction is compared with a preset first change extreme value and / or the second change value used for the second pressure direction is compared with a preset second change extreme value, and when the first change value exceeds the first change extreme value and / or the second change value exceeds the second change extreme value, the processing mechanism (32) outputs a diagnostic signal.

14. The method according to claim 11, characterized in that, For the closed valve diagnosis, the position signal of the position sensor assembly is evaluated to determine the duration of movement of the working piston (18) between the first end position (13) and the second end position (14), and when the duration of movement exceeds a preset deviation from a preset extreme value of the duration of movement, the processing mechanism (32) outputs a diagnostic signal.

15. The method according to claim 11, characterized in that, For the closed valve diagnosis, the first pressure direction is evaluated with regard to fluctuations having a preset frequency and / or a preset amplitude, and when it appears within a preset frequency range and / or has a preset minimum amplitude fluctuation, the processing mechanism (32) outputs a diagnostic signal.

16. The method according to claim 14, characterized in that, When the movement duration is lower than the preset movement duration extreme value, the processing mechanism (32) outputs a diagnostic signal.

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