PNEUMATIC ACTUATOR AND UNIT

Description

[0001] The invention relates to a pneumatic actuating device for pneumatically actuated devices and to a pneumatic unit with such a pneumatic actuating device and with a pneumatically actuated device which has at least one pressure chamber.

[0002] A mini-compressor is known from DE 20 2006 008 219 U1. This mini-compressor is switched on when connected to a power source and switched off when the power source is disconnected. Document DE 10 2009 037120 A1 discloses a pneumatic actuating device for pneumatically actuated devices, comprising a control assembly that controls an electric motor driving a compressor.

[0003] The present invention is based on the problem of developing an actuating device for operation in a pneumatic unit, wherein the actuating device can be used together with differently constructed pneumatically actuated devices without modifications.

[0004] This problem is solved by the features of the main claim. For this purpose, a control assembly controls an electric motor driving a compressor by means of at least one pressure switch and a temperature switch electrically connected in series with the pressure switch. At least one directional control valve with a spring-loaded blocking position, switchable by means of a valve switch arranged in or on the control assembly, is electromagnetically actuated. Furthermore, the volume of a pressure line between the compressor and the directional control valve is less than 500 cubic millimeters.

[0005] In the pneumatic unit, each pressure chamber is defined by a piston. At least one pressure output of the actuating device and at least one pressure chamber are connected by a connecting line. Furthermore, the sum of the volumes of the connecting line and at least one pressure chamber is greater than ten times the volume of the pressure line.

[0006] The pneumatic actuator has a small storage volume. Each opening of the directional valve is controlled by the control module. The temporary increase in the pneumatic system volume when the directional valve opens causes the pressure to drop. As soon as the pressure, as measured by the pressure switch, reaches a lower switching point, the control module checks the switching state of the thermal switch. Depending on the cumulative result of the two tests, the control module starts the compressor motor. The control module can be used to adjust the parameters of the actuator and the parameters of the device's operating procedure, e.g., the pressure build-up curve, the valve switching delay, etc. This allows the actuator to be connected quickly and easily to a pneumatically operated device.

[0007] Further details of the invention emerge from the subclaims and the following description of schematically illustrated embodiments. Figure 1: Pneumatic actuating device; Figure 2: Top view of the open actuating device; Figure 3: Pneumatic unit with linear clamping device; Figure 4: Control module; Figure 5: Linear clamping device in the closed state; Figure 6: Linear clamping device in the released state; Figure 7: Pneumatic unit with zero-point clamping system; Figure 8: Zero-point clamping system in the pressure-free closed state; Figure 9: Zero-point clamping system with locked combination bolt; Figure 10: Pneumatic unit with a cylinder-piston unit. Figure 11: Pneumatic unit with internal valve switches.

[0008] The Figures 1 and 2show a pneumatic actuating device (10). Such actuating devices (10) are used, for example, to actuate pneumatically actuated devices (200). The individual pneumatically actuated device (200) can be monostable or bistable. Pneumatically actuated devices (200) are, for example, braking and / or clamping devices (220), cf. Figures 3 - 6 , gripping devices or clamping devices (320), cf. Figures 7 - 9 , cylinder-piston units (420), cf. Figure 10 .

[0009] When operating a monostable pneumatically operated device (200), cf. Figure 10, a pressure or displacement chamber (423) defined by a displaceable piston (422) is loaded against the force of, for example, a mechanical return spring (425). A bistable device (200), for example, has two pressure chambers separated by a piston, which are alternately pressurized with pneumatic pressure.

[0010] Braking and / or clamping devices (220) or clamping devices (320) are used, for example, in machine tools to hold guides or workpieces in a position relative to the machine bed. This holding is ensured, for example, by means of the mechanical spring (235, 243; 342) of the braking, clamping, or tensioning element.

[0011] A gripping device can be either monostable or bistable. For example, a monostable gripping device has a return spring that acts in the closed gripping position, ensuring the gripping pressure when gripping an object. In a bistable gripping device, an opening or closing movement is pneumatically actuated alternately at different times.

[0012] The Figures 1 and 2 The pneumatic actuating device (10) shown has a housing (11) consisting of a base part (12) and a cover part (13) screwed to the base part. The housing (11) has a square base with an edge length of, for example, 150 millimeters. The height of the housing (11) is, for example, 60 millimeters. At each corner (14) of the base part (12) there is a threaded hole (15) into which a cover fastening screw is screwed when the housing (11) is closed.

[0013] In the illustrated embodiment, all external connections and operating elements are located on the rear side (16) of the housing (11). A main switch (21) is located on the left. An electrical connection rail (22) is located in the center. In the illustration of the Figure 1The two left-hand electrical connections (23, 24) of the connecting rail (22) are used to connect a power source. The power source is, for example, a direct current source with a voltage of 24 volts. In this case, the left-hand connection is the potential connection (23) and the right-hand connection is the ground connection (24). The other electrical connections (25 - 27) in the exemplary embodiment are a potential output connection (25) and two valve switching connections (26, 27). The potential output connection (25) can have the potential of the direct current source or another electrical potential relative to the electrical ground. The two valve switching connections (26, 27) are, for example, potential-free when not in use. In the illustrations of the Figures 1 and 3A first valve switch (41) is arranged between the potential output connection (25) and the first valve switching connection (26). This valve switch (41) can be operated manually or by program control. In the case of program-controlled operation, the operation can be carried out, for example, by means of a higher-level control system, e.g., a programmable logic controller. The valve switch (41) can also be arranged within the housing (11), e.g., in the case of program-controlled operation. A second valve switch (51) is shown in the circuit diagram of the Figure 3arranged between the potential output connection (25) and a second valve switching connection (27). This second valve switch (51) can be designed and arranged in the same way as the first valve switch (41). If the valve switches (41, 51) are arranged within the housing (11), the external valve switches (41, 51) can be omitted. In this case, the potential output connection (25) and the valve switching connections (26, 27) can also be omitted.

[0014] The housing (11) can have data connections (28) and / or signal connections (29), cf. Figure 11 These connections can be used to exchange data and / or signals, for example, with a higher-level controller. Signal exchange can occur in both directions.

[0015] In the exemplary embodiment, three pneumatic pressure outlets (31 - 33) are arranged on the rear side (16) of the housing (11). A first pressure outlet (31) is connected downstream of a first electromagnetically actuated directional control valve (42). A second pressure outlet (32) is connected downstream of a second electromagnetically actuated directional control valve (52). The third pressure outlet (33) is designed, for example, without an upstream directional control valve. In the exemplary embodiment of the Figures 1 - 6 The third pressure outlet (33) is closed by a closure element (34). A design with only one pressure outlet (31; 32; 33) is also conceivable. This is then designed in the same way as the aforementioned first pressure outlet (31).

[0016] Below the first pressure connection (31) and the second pressure connection (32) is the Figure 1 A vent outlet (35) is arranged. This outlet has, for example, a protective filter (36).

[0017] In the left area of ​​the back (16) the illustration of the Figure 1 An intake port (37) is arranged. This has an intake filter (38) that prevents the intake of contaminants.

[0018] In the exemplary embodiment, a compressor unit (61), a pressure switch (71), a temperature switch (75), two electromagnetically actuated directional control valves (42, 52) and a control assembly (81) are arranged within the housing (11).

[0019] The compressor unit (61) comprises an electric motor (62) and a pneumatic compressor (63). It has a connected load of, for example, 120 watts. Its test pressure in the illustrated example is 10 bar. A volume of 10 6< cubic millimeters is increased from ambient pressure to 0.6 megapascals within 40 seconds, for example. The compressor (63) in the illustrated example is a piston compressor. Its flow rate at the specified pressure is, for example, 8.44 Pascal times cubic meters per second [Pa × m 3< / s].

[0020] The intake port (37) is connected to the intake filter (38) on the intake side of the compressor (63). The compressor (63), driven by the electric motor (62), draws in air from the environment (1) through this port. The compressed air is conveyed into a pressure line (65) on the pressure side (64) of the compressor (63).

[0021] The pressure switch (71) is located on the pressure side (64) of the compressor (63). The pressure switch (71) has an upper switching point and a lower switching point. The pressure value of the upper switching point and / or the lower switching point can be adjustable. To adjust the lower switching point, the hysteresis of the pressure switch can be adjustable. In the exemplary embodiment, the pressure value of the lower switching point is greater than the ambient pressure. For example, it is also greater than or equal to half the pressure value of the upper switching point. For example, the upper switching value is set to 0.6 Pascal and the lower switching point to 0.3 Pascal. The pressure switch (71) is closed when the determined increasing pressure is less than the pressure value of the upper switching point. If this pressure value is exceeded, the pressure switch (71) is opened. The pressure switch (71) can also output a pressure-dependent signal.This is, for example, an analog signal between 4 milliamperes and 20 milliamperes. This can be used to monitor the actual pressure.

[0022] The temperature switch (75) is mounted on the compressor housing (66) of the compressor unit (61). The switching point of the temperature switch (75) is, for example, 55 degrees Celsius. This switching value and the hysteresis of the temperature switch (75) can be adjustable. The temperature switch (75) is closed, for example, at room temperature. When the switching point is exceeded, the temperature switch (75) opens, interrupting an electrical circuit connected to it. The temperature switch (75) can output a temperature-dependent signal, for example, an analog signal.

[0023] The two electromagnetically operated directional control valves (42, 52) are identical to one another in the exemplary embodiment. The directional control valves (42, 52) are pneumatically connected in parallel. They are designed, for example, as 3 / 2-way valves with spring return to the blocked position. Another design of the directional control valves (42, 52) is also conceivable. In the operating position, the individual directional control valve (42; 52) is connected to the pressure side (64) of the compressor (63) by means of the pneumatic line. The individual directional control valve (42; 52) is thus arranged pneumatically parallel to the pressure switch (71). In the blocked position, the directional control valve (42; 52) is connected to the vent outlet (35). The other side of the directional control valve (42; 52) is connected to a pressure outlet (31; 32) of the housing (11) in both switching positions. The third pressure outlet (33) is connected to the pressure side (64) of the compressor (63) without the interposition of a directional control valve (31; 32).

[0024] The control module (81) is arranged between the aforementioned components and the electrical connections (23-27) as well as, for example, the data and signal connections (28, 29) on the rear side (16) of the housing (11). It can comprise one or more circuit boards. These can be arranged adjacent to one another or spaced apart from one another in the housing (11). The control module (81) shown, cf. Figures 3 , 4 , 7 , 10 and 11 , for example, has 16 connections (82 - 98), of which 12 connections (82 - 86, 91 - 94, 96 - 98) are occupied in the first embodiment.

[0025] The first terminal (82) is a potential input terminal (82). This is electrically located behind the main switch (21). The second terminal (83) is a ground terminal (83). This second terminal (83) electrically connects the control module (81) to the ground terminal (24) of the housing (11). The ground terminal (24) of the housing (11) also serves, for example, as the star point for the remaining ground lines within the housing (11).

[0026] In the exemplary embodiment, the third terminal (84) of the control module (81) is connected to the potential output terminal (25) of the housing (11). The potential of this potential output terminal (25) corresponds, for example, to the electrical potential required to actuate the directional control valves, e.g., 5 volts, 12 volts, or 24 volts. The required voltage value can be adjustable.

[0027] The fourth port (85) of the control assembly (81) is connected to the first valve switching port (26) of the housing (11). The fifth port (86) is connected to the second valve switching port (27) of the housing (11).

[0028] The sixth connection (87) is a data connection (87). Via this data connection (87), data can be exchanged, for example, bidirectionally between a higher-level controller and the pneumatic actuating device (10). In use, this data connection (87) is connected, for example, to a data connection sleeve (28) on the rear (16) of the housing (11). This sixth connection (87) is not occupied in the exemplary embodiment. Instead of the sixth connection, a wireless transmitting / receiving device can also be provided in the control module (81). It is also conceivable, for example, to design the data connections for incoming and outgoing data separately. The data can be transmitted, for example, in packet form. They include, for example,the pressure values ​​for the switching values ​​of the pressure switch (71) and the temperature switch (85), the time course of the motor voltage of the electric motor (62) and / or the volume flow of the compressor (63), switching times for the directional control valves (42; 52), the time sale of a throttle curve of a throttle valve possibly arranged upstream of the vent outlet (35), etc.

[0029] The seventh connection (88) of the control module (81) is a signal connection (88). It can be connected to the signal connection sleeve (29) of the housing (11). This signal connection (88) is used, for example, to transmit binary start signals from a higher-level controller to the pneumatic actuating device (10). This can be used, for example, to start or interrupt sequence programs in the control module (81). Furthermore, a binary signal, for example, about the completion of a program sequence, can be transmitted to the higher-level controller via the signal connection (88). It is also conceivable to design signal connections for incoming and outgoing signals separately. Wireless transmission of the signals is also conceivable. In the exemplary embodiment, the seventh connection (88) is not occupied.

[0030] The eighth port (89) of the control module (81) is a reserve port (89) in the illustrated embodiment. An adjustable throttle for the return air flow can be connected to this port (89), for example.

[0031] The ninth port (91) is a second valve port (91). The valve coil (53) of the second directional control valve (52) is connected to this ninth port. The valve coil (43) of the first directional control valve (42) is connected to the tenth port (92), a first valve port (92).

[0032] The eleventh connection (93) and the twelfth connection (94) are used to connect the pressure switch (71). Here, for example, the eleventh connection (93) is the inlet connection (93) of the pressure switch (71). The twelfth connection (94) is the operating connection (94). This connection (94) is connected to the inlet connection (93) in the pressure switch (71) if, for example, the pressure on the pressure side (64) of the compressor (63) is lower than the value of the lower switching point before the compressor (63) starts up. When the compressor unit (61) is in operation, the pressure switch (71) remains in this closed position as long as the pressure on the pressure side (64) is lower than the pressure value of the upper switching point of the pressure switch (71).

[0033] The thirteenth connection (95) is a data connection (95). This data connection (95) can be used, for example, to adjust the pressure switch (71) and / or the temperature switch (75). Analog data from the pressure switch (71) and / or the temperature switch (75) can also be exchanged with the control module (81).

[0034] The temperature switch (75) is connected to the fourteenth terminal (96) and the fifteenth terminal (97). The temperature switch (75) is connected in series with the pressure switch (71).

[0035] The fifteenth connection (97) controls the sixteenth connection (98), which is a motor control connection (98). The pressure switch (71) and the temperature switch (75) are parts of a motor control circuit (99) that controls the electric motor (62). If the motor control circuit (99) is open, the motor control connection (98) is de-energized. The motor control circuit (99) is open when either the pressure determined at the pressure switch (71) has reached the upper switching point and / or the temperature (75) determined at the temperature switch (75) has exceeded the temperature limit. Each of the two switches (71, 75) remains open during the decreasing hysteresis. The motor current is only switched on when both the pressure switch (71) and the temperature switch (75) are closed.

[0036] A different assignment of the connections (82 - 98) is also conceivable.

[0037] The control module (81) is designed as a microcontroller in the exemplary embodiment. Figure 4 shows a simplified structure of the control module (81). The control module (81) has, for example, a computer and memory unit (101) for regulating and / or controlling the individual functions of the pneumatic actuating device (10). In the illustration of the Figure 4 The computer and storage unit (101) is depicted as a programmable logic device (PLD) with memory (102). The computer and storage unit (101) is designed to process data and signals transmitted from outside the pneumatic actuating device (10). It can also transmit data and signals from the pneumatic actuating device (10), for example, to a higher-level controller, a mobile programming unit, etc.

[0038] The memory (102) is designed, for example, as a data and sequence program memory. For example, a plurality of sequence programs are stored in the memory (102). The computer and storage unit (101) can, for example, start a predetermined sequence program from a plurality of stored sequence programs. Such a sequence program contains, for example, as parameters at least one motor voltage curve, a pressure value for the upper switching point of the pressure switch (71), a pressure value for the lower switching point or a value for the hysteresis of the pressure switch (71), and a limit temperature value for the temperature switch (75) as well as its hysteresis. When controlling the motor voltage curve, for example, the voltage in the electrical connection (103) between the potential input connection (82) and the motor control connection (98) and thus the speed of the compressor unit (61) is influenced. The data transmission takes place, for example,via a motor control line (113) from the computer and storage unit (101). The electric motor (62) is controlled both by the motor control circuit (99) and by the computer and storage unit (101). It is also conceivable to control the pressure build-up time, the air flow, the pressure build-up curve, etc.

[0039] The Figure 4The control module (81) shown has a triple switch (104) and two internal valve switches (44, 54) in the valve control area. The triple switch (104) is arranged in the lines from the third connection (84) to the fifth connection (86). The switching elements (106, 107) in the lines of the fourth and fifth connections (85, 86) are designed to be opposite to the switching element (105) of the third connection (84). Thus, when the first switching element (105) is closed, the other two switching elements (106, 107) are opened and vice versa. In the illustration of the Figure 4 The first switching element (105) is shown in the open state. The triple switch (104) can be actuated by means of the computer and storage unit (101). For this purpose, a signal line (108) is used, for example.

[0040] A diode bridge (109) is connected downstream of the triple switch (104). This bridge connects the line of the third terminal (84) with the line of the fourth terminal (85). Furthermore, a line bridge (111) downstream of the triple switch (104) connects the line of the third terminal (84) with the line of the fifth terminal (86).

[0041] An internal first valve switch (44) is connected downstream of the second switching element (106). This is actuated by the computer and storage unit (101) via a valve switching line (112). A second internal valve switch (54) is connected downstream of the third switching element (107). The second internal valve switch (54) can also be actuated by the computer and storage unit (101) via the valve switching line (112). The two internal valve switches (44, 54) can be switched simultaneously or at different times. It is also conceivable to actuate only one of the internal valve switches (44; 54).

[0042] The main switch (21) is located in the control module (81), see. Figure 4 The pressure switch (71) and the at least one valve switch (41; 44; 51; 54) are electrically connected in parallel to one another. When the first switching element (104) is open, the two inner valve switches (44, 54)—shown open for clarity—are generally closed.

[0043] In the exemplary embodiment, the pressure line (65) between the compressor (63) and the directional control valves (42, 52) has a length of 70 millimeters and an outer diameter of four millimeters. The inner diameter of the pressure line (65) is, for example, 2.5 millimeters. Thus, the volume enclosed in the pressure line (65) between the compressor (63) and the at least one pneumatic directional control valve (42; 52) is 344 cubic millimeters. The enclosed volume of the pressure line (65) is, for example, less than 500 cubic millimeters. The pressure outlets (31 - 33) can be designed for line cross-sections that are equal to or larger than the cross-section of the pressure line (65).

[0044] The pneumatic actuating device (10) is operated independently of the compressed air network, e.g., in a production hall. It can be mounted on a machine tool, an industrial robot, etc., for example, in a safe area. A pneumatic connecting line (150) connects the pneumatic actuating device (10) to a pneumatically actuated device (200). The actuating device (10), the actuated device (200), and the connecting line (150) together form a pneumatic unit (9).

[0045] The Figure 3 shows the circuit diagram of a pneumatic unit (9) with two pneumatically actuated devices (200). The latter are designed as braking and / or clamping devices (220) in the form of linear clamping devices (220). Figures 5 and 6 show such a linear clamping device (220) in the two operating positions.

[0046] The linear clamping device (220) engages around a rod-shaped guide rail (290). The linear clamping device (220) has a C-shaped base body (221) for the engagement.

[0047] The base body (221) has, for example, a cuboid-shaped cylinder section (222), two spring-joint sections (223), and two friction jaw sections (224). The cylinder section (222) has, for example, two recesses (225) offset from one another in the longitudinal direction. The two recesses (225) have, for example, identical geometric dimensions. These recesses (225) delimit pressure chambers (226) of the linear clamping device (220).

[0048] The spring joint section (223) adjoins the cylinder section (222) on both sides. The single spring joint section (223) forms an elastic bending beam.

[0049] Each spring joint section (223) is connected to a friction jaw section (224). The latter serves as a support for the friction jaws (227) screwed to it.

[0050] A pneumatic piston (231) is sealed in each of the recesses (225). The pneumatic piston (231) delimits the pressure chamber (226) in the direction of the guide rail (290). The pneumatic piston (231) consists of a piston plate (232) and two sliding wedges (233) projecting from it. The piston plate (232) has an annular groove in which a piston sealing ring (234) is seated. A return spring element (235) is inserted into each of the sliding wedges (233).

[0051] The base body (221), the pneumatic piston (231), and the friction jaw (227) enclose a rolling element cage (241) in the area of ​​the respective spring joint section (223). Each rolling element cage (241) carries, for example, two cylindrical rollers (242) or needles as rolling elements. To the sides of the cylindrical rollers (242), the rolling element cages (241) each accommodate a helical compression spring (243) supported by the nearest friction jaw (227).

[0052] The representation of the Figure 5 shows the linear clamping device (220) in the closed position. The pneumatic piston (231) is held there by the return spring elements (235). Likewise, the helical compression springs (243) secure the upper position of the respective rolling element cage (241). In this operating state, the linear clamping device (220) is clamped to the guide rail (290). The spring joint section (223) applies the necessary clamping force.

[0053] During operation of the braking and / or clamping device (220), a connecting line (150) connects the pneumatic actuating device (10) to a pressure chamber (226) of the linear clamping device (220). The main switch (21) of the actuating device (10) is switched on, and the valve switches (41, 51; 44, 54) are open when the braking and / or clamping device (220) is clamped. The directional control valves (42, 52) are in a blocking position. In the blocking position of the respective directional control valve (42; 52), there is no pneumatic connection between the pressure side (64) of the compressor (63) and the respectively associated pressure outlet (31; 32) of the housing (11). In the exemplary embodiment, a connecting line (150) is connected to both the first pressure outlet (31) and the second pressure outlet (32) of the actuating device (10).

[0054] To release the braking and / or clamping device (220), two valve switches (41, 51; 44, 54) of the pneumatic actuating device (10), for example, are closed. The closing of the valve switches (41, 51; 44, 54) can be controlled, for example, by the higher-level control system or the computer and storage unit (101). The solenoid coil (43; 53) of the respective directional control valve (42; 52) is energized. The directional control valve (42; 52) is opened into the operating position against the force of the respective valve spring (45; 55). If only one connecting line (150) is connected to the pneumatic actuating device (10), only the respective associated valve switch (41; 44; 51; 54) is actuated.

[0055] When the directional control valve (42; 52) opens, the compressed air from the pressure line (65) is released into the connecting line (150). For example, the internal volume of the connecting line (150) is larger than the internal volume of the pressure line (65). The pressure monitored by the pressure switch (71) decreases. As soon as the pressure has fallen to a value below the pressure value of the lower switching point, the electric motor (62) is switched on. The air pressure in the pneumatic system (151) is increased by means of the compressor (63). In the braking and / or clamping device (220), the pneumatic piston (231) is moved against the restoring force of the return springs (235, 243) in the illustrations of the Figures 5 and 6The pressure chamber (226) is displaced downwards, enlarging the pressure chamber (226). The cylindrical rollers (242) roll downwards and spread the friction shoe sections (224) outwards. As soon as the pneumatic piston (231) has reached its lower end position, the cylindrical rollers (242) with the rolling element cages (241) are also in their lower end position. The friction shoes (227) no longer have contact with the guide rail (290), see. Figure 6 The clearance, for example, is several tenths of a millimeter. In this state, the volume of the individual pressure chamber (226) is at least ten times the volume of the pressure line (65).

[0056] As soon as the pressure measured at the pressure switch (71) in the entire pneumatic system (151) has increased to the upper switching point, the motor (62) is switched off. The guide rail (290) can now be moved longitudinally relative to the braking and / or clamping device (220).

[0057] To close the braking and / or clamping device (220) again, the associated valve switch (41; 44; 51; 54) is opened. The current supply to the solenoid coil (43; 53) is switched off. The directional control valve (42; 52) is switched to the blocking position by means of the valve spring (45; 55). The connecting line (150) is connected to the vent outlet (35). The pressure in the pressure chamber (226) and in the connecting line (150) is reduced to the ambient pressure. In the braking and / or clamping device (220), the return springs (235, 243) move the pneumatic piston (231) to its starting position. The base body (221) deforms back into its starting position. The guide rail (290) is clamped. In the embodiment, the response time of the pneumatic unit (9) when clamping is shorter than the response time when releasing the clamp.For example, from the actuation of the valve switch (41; 44; 51; 54), the time interval for the release movement of the braking and / or clamping device (220) is more than twice as long as the time interval for clamping the braking and / or clamping device (220).

[0058] If, for example, a leak occurs in the pneumatic system (151), the pressure in the pneumatic system (151) will not build up within a specified time interval. The compressor unit (61) will continue to operate. If necessary, a warning message can be issued. If the temperature determined by the temperature switch (75) exceeds the specified limit, the electric motor (62) will be shut down.

[0059] The Figure 7shows a pneumatic unit (9) with a pneumatic actuating device (10) and with a pneumatically actuated device (200) in the form of a clamping system (320). The pneumatic actuating device (10) is constructed, for example, as described in connection with the first exemplary embodiment. An external pressure accumulator (121)—shown here with thin lines—can be connected to the third pressure output (33) of the housing (11).

[0060] The circuit in the Figure 7 The clamping system (310) used is, for example, a zero-point clamping system (310). Such clamping systems (310) are used to fix workpieces on workpiece tables. Figures 8 and 9 show the structure of such a clamping system (310).

[0061] The clamping system (310) consists of a clamping device (320) and a combination bolt (311). The clamping device (320) is integrated, for example, into a machine table to hold a workpiece. Typically, at least one combination bolt (311) is attached to the workpiece to be clamped. The clamping device (320) has a mechanism that positions the combination bolt (311) in the clamping device (320) with repeatable accuracy.

[0062] The clamping device (320) has a clamping device housing (321) that essentially consists of a flange-like housing base body (324) and a housing cover (325) located in the underside of the housing base body (324). The one-piece housing base body (324) consists of a flange plate (326) and a cylinder (327) molded onto it.

[0063] The flange plate (326) has in the illustrations of the Figures 8 and 9On the left side, there is a duct system (331) through which any dynamic pressure present between the flange plate (326) and the workpiece resting thereon can be fed to a measuring device to check correct workpiece support. The air supply can be provided by means of the actuating device (10).

[0064] The flange plate (326) has a central receiving recess (328) in its center, which is surrounded by a support tube (329) formed integrally on the flange plate (326). This support tube (329) serves as the internal guide for the annular piston (323).

[0065] The housing cover (325) is centered and sealed within the housing base (324). It has a stop tube (341) at its center, which extends into the housing base (324). The outer wall of the stop tube (341) also guides the annular piston. Furthermore, the housing cover (325) accommodates, for example, twelve helical compression springs (342). A clamping ring (343) is arranged between the end faces of the support tube (329) and the stop tube (341).

[0066] In the presentation of the Figure 8 The clamping device (320) is in its depressurized, unactuated initial state. A closure cap (332) is in its closed position. At the same time, the annular piston (323) rests against the bottom of the cylinder (327) due to the action of the helical compression springs (342). The clamping ring (343) contacts the annular piston (323).

[0067] To actuate the clamping device (320), pneumatic pressure is applied to the rear piston crown (344) of the annular piston (323) by means of the actuating device (10). The front face of the closure cap (332) and the retaining combination bolt (311) are cleaned with compressed air.

[0068] The pneumatic pressure applied to the annular piston front (345) displaces the annular piston (323) by tensioning the helical compression springs (342) on the housing cover (325). The pressure chamber (322) is enlarged. As the combination bolt (311) is further inserted, it presses the clamping ring (343) into the annular piston (323).

[0069] In the presentation of the Figure 9 The combination bolt (311) has come into contact with the flange plate (326). The clamping ring (343) has contracted to its original position.

[0070] The release of the combination bolt (311) essentially occurs in the reverse order. The annular piston (323) is pressed against the housing cover (325) with compressed air, which displaces the clamping ring (343) toward the annular piston (323) when the combination bolt (311) is pulled out. The compressed air required to release the combination bolt (311) is also provided by the pneumatic actuation device (10).

[0071] The Figure 10shows a circuit diagram of a further embodiment of a pneumatic unit (9). The pneumatic actuating device (10) is largely designed as described in connection with the previous exemplary embodiments. The two directional control valves (42; 52) are not electrically connected. The respective pressure outputs (31, 32) are closed. An external pressure accumulator (121) is connected to the third pressure output (33). An external pneumatic directional control valve (122) is connected downstream of this pressure accumulator (121). This directional control valve (122) can, for example, be constructed like one of the directional control valves (42; 52) arranged within the housing (11). The pressure accumulator (121) and the directional control valve (122) can, for example, be arranged directly at the consumer. The electrical control and / or actuation of this external directional control valve (122) takes place, for example, on the consumer side, by means of the machine control system, etc.

[0072] The pneumatically actuated device (200) shown has a single-acting cylinder-piston unit (420) with a spring return. In a cylinder (421), a movable piston (422) separates a displacement chamber (423) from a compensation chamber (424). The connecting line (150) is connected to the displacement chamber (423). The compensation chamber (424) is connected to the environment (1). A return spring (425) in the form of a helical compression spring is arranged in the compensation chamber (424), which loads the piston (422). When pressure is applied to the displacement chamber (423), the piston (422) is displaced towards the compensation chamber (424) under the load of the return spring (425). The piston rod (426) attached to the piston (422) is extended. As soon as the directional control valve (122) is switched to the blocking position, the displacement chamber (423) is relieved via the directional control valve (122).The piston (422) is moved in the direction of the displacement chamber (423) by means of the return spring (425).

[0073] In the Figure 11 A further variant of a pneumatic unit (9) is shown. The pneumatically operated device (200) corresponds, for example, to the one described in connection with the embodiment of the Figures 1 - 6 pneumatically operated device (200) shown.

[0074] The Figure 11 The pneumatic actuating device (10) shown has no external valve switches (41, 42). The internal valve switches (44, 54) of this exemplary embodiment are actuated by means of the computer and storage unit (101), as described above. The housing (11), for example, has both a data connection sleeve (28) and a signal connection sleeve (29). Within the housing (11), the data connection sleeve (28) is connected to the data connection (87) of the control module (81), cf. Figure 4, connected. The signal connection sleeve (29) is connected to the signal connection (88) of the control module (81). The pneumatic unit (9) is actuated as described above.

[0075] Combinations of the individual embodiments are also conceivable. List of reference symbols:

[0076] 1Environment 9pneumatic unit 10pneumatic actuating device 11housing 12base part 13cover part 14corner of (12) 15threaded hole 16rear 21Main switch, operating element 22Connection rail 23Potential connection, electrical connection 24Ground connection, electrical connection 25Potential output connection 26Valve switching connection 27Valve switching connection 28Data connection sleeve 29Signal connection sleeve 31Pressure outlet, first pressure outlet 32Pressure outlet, second pressure outlet 33Pressure outlet, third pressure outlet 34Closing element 35Vent outlet 36Protective filter 37Intake connection 38Intake filter 41Valve switch, first valve switch 42Directional control valve, first directional control valve 43Valve coil, solenoid coil 44Valve switch, inner first valve switch 45Valve spring 51Valve switch, second valve switch 52Directional control valve, second directional control valve 53Valve coil, solenoid coil 54Valve switch, inner second valve switch 55Valve spring 61Compressor unit 62Electric motor 63Compressor 64Discharge side 65Pneumatic line, pressure line 66Compressor housing 71Pressure switch 75Temperature switch 81Control module 82First connection, potential input connection 83Second connection, ground connection 84Third connection 85Fourth connection 86Fifth connection 87Sixth connection, data connection 88Seventh connection, signal connection 89Eighth connection, reserve connection 91ninth port, second valve port 92tenth port, first valve port 93eleventh port, input port 94twelfth port, operating port 95thirteenth port, data port 96fourteenth port 97fifteenth port 98sixteenth port, motor control port 99motor control circuit 101Computer and storage unit 102Memory 103Electrical connection between (82) and (98) 104Triple switch 105Switching element of (104), first switching element 106Switching element of (104), second switching element 107Switching element of (104), third switching element 108Signal line 109Diode bridge 111Cable bridge 112Valve switching cable 113Engine control cable 121External pressure accumulator 122External pneumatic directional control valve 150Connecting line 151Pneumatic system 200pneumatically operated device 220Braking and / or clamping device, linear clamping device 221Base body 222Cylinder section 223Spring joint sections 224Friction shoe sections 225Recesses 226Pressure chambers 227Friction shoes 231Pneumatic piston 232Piston plate 233Sliding wedges 234Piston sealing ring 235Return spring element 241Rolling element cage 242Cylindrical rollers 243Coil compression spring, return spring 290Guide rail 310Clamping system 311Combination bolt 320Clamping device 321Clamping device housing 322Pressure chamber 323Annular piston 324Housing body 325Housing cover 326Flange plate 327Cylinder 328Receptacle 329Support tube 331Channel system 332Closing cap 333Cross bore 341Stop tube 342Coil compression springs 343Clamping ring 344Piston crown 345Annular piston front 420Cylinder-piston unit 421Cylinder 422Piston 423Displacement chamber, pressure chamber 424Compensation chamber 425Return spring 426Piston rod µC microcontroller PLD programmable logic device

Claims

1. A pneumatic actuator (10) for pneumatically operated devices (200), - wherein a control module (81) controls an electric motor (62), which drives a compressor (63), at least by means of a pressure switch (71) and a temperature switch (75) electrically series-connected thereto, - wherein at least one directional valve (42; 52) can be operated electromagnetically, which can be switched by means of a valve switch (41; 44; 51; 54) arranged in or on the control module (81) and has a spring-loaded blocking position, - wherein the volume of a pressure line (65) between the compressor (63) and the directional valve (42; 52) is less than 500 cubic millimetres.

2. The pneumatic actuator (10) according to Claim 1, characterised in that at least the control module (81), the pressure switch (71), the temperature switch (75), the electric motor (62), the compressor (63) and the directional valve (42; 52) are arranged in a common housing (11).

3. The pneumatic actuator (10) according to Claim 1, characterised in that the pressure switch (71) has a hysteresis with a settable upper switch point and / or a settable lower switch point.

4. The pneumatic actuator (10) according to Claim 1, characterised in that the control module (81) has a computer and memory unit (101).

5. The pneumatic actuator (10) according to Claim 4, characterised in that a plurality of sequence programs can be stored in the computer and memory unit (101), which each contain, as parameters, at least one motor current curve, a pressure value for the upper switch point of the pressure switch (71), a pressure value for the lower switch point of the pressure switch (71), and a limit temperature value for the temperature switch (75) .

6. The pneumatic actuator (10) according to Claim 1, characterised in that at least two pneumatically parallel-connected pneumatic directional valves (42, 52) are arranged inside the housing (11), wherein each pneumatic directional valve (42; 52) is assigned at least one valve switch (41; 44; 51; 54) and a pressure output (31; 32).

7. The pneumatic actuator (10) according to Claim 6, characterised in that the valve switches (44, 54) are arranged inside the housing (11) and can be switched consecutively by means of the control module (81).

8. The pneumatic actuator (10) according to Claim 1, characterised in that the pressure switch (71) and the valve switch (41; 44; 51; 54) are connected electrically parallel to one another downstream of a main switch (21) and a potential input terminal (82) of the control module (81).

9. The pneumatic actuator (10) according to Claim 1, characterised in that it has a valveless pressure output (33), which is pneumatically connected downstream of the compressor (63).

10. A pneumatic unit (9) having a pneumatic actuator (10) according to Claim 1 and having a pneumatically operated device (200) that has at least one pressure chamber (226; 322; 423), characterised in that - each pressure chamber (226; 322; 423) is delimited by means of a piston (231; 323; 422), - at least one pressure output (31; 32) of the actuator (10) and at least one pressure chamber (226; 322; 423) are connected by means of a connecting line (150), and - the sum of the volumes of the connecting line (150) and at least one pressure chamber (226; 322; 423) is greater than ten times the volume of the pressure line (65).