EP0984170B1 - Fluid pressure cylinder, switch valve and pressure actuated work unit - Google Patents

Abstract

Pneumatic cylinder assembly has a direction change valve (V) and a system of bleed valves (24a, 24b) (27a, 27b) to pass pressure to the working zones of the cylinder (A) in a smaller valve structure. The pneumatic cylinder assembly, to convert pneumatic pressure into mechanical energy, has a let-off opening fitted with a valve (13a,13b) controlled by the pressure of the working medium at the feed opening. A direction change valve (V), and especially in a rocker valve structure, has at least one entry and one outlet for the working medium and a let-off channel between the valve unit and at least one outlet. The channel has an outlet and bleed control valve which is controlled electrically or by the pressure. The unit, which is operated by the pneumatic system, has a pneumatic working cylinder (A) with bleed valves (27a,27b), a direction change valve (V) and bleed control valves (24a,24b), and a pressure line (29a,29b) to each working zone of the cylinder (A).

Description

The invention relates to a valve arrangement with a through which on the control connection applied pressure between two switch positions, switchable rocker sealing element (31, 33) and at least one control space (34a, 34b) delimited by the rocker sealing element, and an exhaust control valve (36a, 36b) which has at least one device (35a, 35b; 37a, 37b) for transmitting the pressure applied to the control connection is in operative connection with the control room (34a, 34b), and a working unit actuated by pressure medium, comprising at least one pressure source (25), at least one possibly double-acting Pressure medium cylinder (A) with at least one drain opening (12a, 12b), which with a valve (13a, 13b; 27a, 27b) is provided, which through the at the feed opening (9a, 9b) applied pressure of the working medium is controllable, at least one valve (V) for controllable Supply of the working cylinder with working medium and at least one line (29a, 29b) for the working medium from the valve to the working cylinder.

For converting pneumatic energy into mechanical power, for example several functions are necessary, that of different components, elements or component groups pneumatic work units are carried out here. That's the way the right of way signal is into a ventilation signal of the corresponding working area of the working cylinder and, if necessary To convert the ventilation signal of the counter chamber, or to link these signals. This is achieved in conventional constructions by the valve, which also applies to the deflection the compressed air to the corresponding work area, the opening of the counter chamber to Cylinder ventilation and the discharge of the exhaust air into the atmosphere ensures. The management of both the Network compressed air to the cylinder, which purely converts the air pressure into mechanical force the cylinder piston, as well as the exhaust air from the cylinder is released into the atmosphere Pneumatic lines carried out. So far, the pneumatic cylinders have been the same Line vented and also vented, although these two processes have different cross sections required. The used to control double-acting pneumatic cylinders So far, valves had to function both because of the deflection of the pressure medium the respective cylinder chamber as well as the ventilation control of the respective counter chamber have very large sizes - while there is a lot of space in the end pieces of the pneumatic cylinders remained unused. The situation with hydraulic units is similar.

From DE-A-2722269 a pressure cylinder is known, in the drain opening Valve is provided, which is determined by the pressure of the working medium at the supply opening is controllable.

A valve with at least one inlet, at least one outlet for a working medium, a control connection and a drain channel for the working medium is in WO-A-9821484 described. Said drain channel goes from a position between the blocking element of the valve and leads to the at least one outlet and includes an outlet or vent control valve, which can be switched by the pressure applied to the control connection is.

GB-A-2089941 discloses a structure of a pneumatic switching valve as a rocker valve, with a rocker sealing element that can be switched between two switching positions. On On one side of this rocker there is a one, limited by the rocker sealing element Control pressure for switching the rocker sealing element between its switching positions loadable control room.

The aim of the present invention is therefore to provide elements for a pressure-operated Work unit and to create such an improved work unit itself, in which a smaller size, at least of the valve, reaches the already existing space, better exploited especially in the cylinder and the performance of the individual elements better and can be coordinated more efficiently.

This aim is achieved according to the invention for a valve arrangement characterized at the outset thereby achieved that, as a device for transmitting the pressure, a part of the wall the control chamber forming flexible membrane is provided, which preferably via a valve stem acts on the actual sealing element, which blocks or releases the drain channel. This is a particularly good one in a structurally simple and very space-saving manner Switchability of the outlet or ventilation control valve guaranteed. Overall, this offers Valve construction for the smallest damaged spaces and fast even for large cross-sections Switching times and exact sealing, which means an immediate, safe and quick ventilation control or control of the outflow of the pressure medium from the working cylinder guaranteed. Due to the small rotary movements of the rocker sufficient for switching the valve according to the invention can be built very small and flat and can be layered Have a structure, both when reassembling and in the event of a repair very simple execution of the work allowed. With the structure of the invention Switch valve is a smaller size than even with two rocker valves for one 5/2-way function.

Of course, with optimal use of the available space and for both sides, for which control is necessary, doubled the advantages mentioned above if the valve arrangement has a structure that is at least functionally the same on both sides having.

A working unit actuated by pressure medium according to the invention is to solve the problem Task according to the invention, characterized in that only per cylinder work space One line each for the working medium to the cylinder and the lines over at least a controllable outlet or vent valve can be vented or relieved, and that the Drain opening of the working cylinder is kept clear.

The best possible and structurally simplest combination of ventilation and ventilation function or to achieve supply and discharge of the working medium is provided, for example, that the control pressure of the valve is present at the control connection of the outlet or vent valve.

The work unit with the at least one double-acting pressure medium cylinder according to an advantageous embodiment, characterized in that the Cylinder only one line is provided for the working medium to the cylinder, and that the Switch valve arrangement is designed as a rocker valve according to one of the above paragraphs.

According to an advantageous embodiment of the invention is in or on the working cylinder a control logic arrangement is provided, the connections for communication, preferably has a fieldbus, electrical control and supply and for the working medium. In order to is a further increase in the compactness of the work unit while still being expanded Versatility possible.

Of course, according to another or additional embodiment, the Invention the valve for controlling one or both working spaces of the working cylinder directly be attached to it or integrated therein, preferably in one of the two end pieces of this Cylinder.

Likewise, the or each vent control valve can advantageously be attached to the working cylinder and / or the switch valve can be attached or structurally integrated into it. In both Cases there is a great simplification in the assembly and arrangement on Slot. Furthermore, lines between these combined components can and in the case of structural integration there are also no connection and sealing points, with which on the one hand, the arrangement of the overall system is considerably simplified and its functional reliability - due to the lower risk of leakage - can be increased significantly. The The aforementioned options are also available when designing the switch valve in a rocker valve design advantageously applicable.

In the following description, some exemplary embodiments for pneumatic Variants will be explained in more detail with reference to the accompanying drawings, wherein however, these examples in no way limit the scope set forth in the claims general inventive idea are to be evaluated.

Fig. 1 shows a longitudinal section through an advantageous in the invention Working unit used working cylinder, Fig. 2 is a partial cross-sectional view a switch valve that can be used for the working unit according to the invention with integrated Vent control valves, Fig. 3 shows a possible embodiment of the switch valve Integrated vent control valves, Fig. 4 and Fig. 5 are schematic circuit diagrams of the invention pneumatic work units, Fig. 6 represents a switch valve in rocker valve design together with the associated vent control valves and Fig. 7 is a Switch valve in rocker valve design with integrated bleed control valves.

The pneumatic working cylinder A shown in Fig. 1, preferably with compressed air as Operated working medium consists of a cylinder tube 1, the ends of which have a bottom 2 and a lid 3 are completed. In this working cylinder A is through the working medium slidably guided a piston 4, which is sealed by a piston rod 5 through the Cover 3 is passed, transmits the mechanical force to the element to be driven. Of course, the invention is in the same way on rodless cylinders and Working media other than compressed air can be used, for example also on hydraulic working media.

Is between the bottom 2 and piston 4, for the double-acting shown Working cylinder A, a first working space 6 defined and between the Cover 3 and the piston 4, a second working space 7, depending on the exposure with the working medium and the vent in the direction of movement of the piston 4 located working space a vented counter chamber to the current working space under pressure. The compressed air is the work spaces via connections 8a, 8b, which into the feed openings 9a, 9b are used, supplied, with them through the supply channels 10a, 10b relatively small cross-section reaches the work rooms 6, 7. Parallel to These feed channels 10a, 10b each have one of the feed openings 9a, 9b Passage 11a, 11b out, leading to two discharge openings 12a, 12b for the air the work rooms 6, 7 leads. There are none at these drain openings 12a, 12b Lines connected, but they lead directly or preferably over a silencer or a speed control throttle and one subsequent silencer (both indicated) in the atmosphere.

The mouth of the passage 11a, 11b lying in the feed opening 9a, 9b forms a valve seat for a located in the feed opening 9a, 9b preferably flat valve element 13a, 13b, this mouth completely covered and advantageously also the mouth of the parallel Feed channels 10a, 10b to work space 6 and 7, at least partially covered. If, for example, in the work space 6 via the assigned, in compressed air is supplied to the connection 8a on the right thereby pressing the right valve element 13a onto its seat and sealing the Passage 11a to the right drain opening 12a. The compressed air arrives on Valve element 13a past into the feed channel 10a and further into the work area 6. This causes the piston 4 to move to the left and the Piston rod 5 extends. If at the same time the left connection causes is depressurized via a vent control valve, this piston movement can in the working chamber 7 which now represents the counter chamber, the left valve element 13b lift off its valve seat, whereby the passage 11b is released and the air from the counter chamber into the atmosphere through the exhaust port 12b can flow out.

Conversely, as soon as the right port 8a is depressurized and the left Connection 8b is supplied with compressed air, the situation is reversed and the left valve element 13b seals the passage 11b so that the compressed air is safely directed only into the work room 7. On the opposite side presses the forced back air from the now counter chamber 6 the valve element 13a high, as soon as the connection 8a is depressurized and the air can over the passage 11a and the drain opening 12a escape. For liquid working media other valve designs may be useful and necessary, but what nothing changes in the principle and mode of operation.

With such a working cylinder A with integrated pressure relief or ventilation can be in the valve V, for example in the version of the Fig. 2, the vent valve arrangement avoided and the size accordingly be made smaller. In the housing 14 of the valve V is the real thing Valve element 15 slidably mounted, which valve element 15 in itself known way a compressed air connection 16 alternately with the two Working connections 17a and 17b connects which working connections 17a, 17b via pressure lines and the connections 8a and 8b on the working cylinder A thereof Supply working rooms 6 and 7 with compressed air. The valve element 15 acted upon by a control pressure, which via the control connections 18 is initiated.

To now the vent control function for the pressure lines in a simple manner to the connections 8a and 8b on the working cylinder into the valve can integrate, according to one embodiment of the valve, a drain channel 19 be provided from a position between the corresponding output 17a, 17b of the valve V and the actual valve element 15 to a drain opening 19a leads into the atmosphere. This drain channel 19 is through a Valve element 20 closed as long as the associated outlet with the compressed air source connected is. As soon as the control signal to switch the direction of movement comes in Fig. 3 by loading the space 21 with the Control pressure, the valve element 20 from its valve piston 22 Lifted the seat and gives the connection from the drain channel 19 through the drain opening 19a released into the atmosphere. The pressure line is then depressurized and in the working cylinder A, the valve element 13a, 13b by the from the previously lifted up with compressed air and the corresponding Ventilated work area.

Of course, the ventilation function just described can also by separate vent control valves 24, as shown in FIG Fig. 4 is shown, the working air lines by solid lines and the control air lines are symbolized by dashed lines. at The pneumatic working unit shown here is the compressed air source 25 connected to the working cylinder A via a switch valve V. The working cylinder A has two vent valves 27a and 27b, for example as in FIG 1 explained, integrated.

The control air lines 28a, 28b lead both to the switch valve V and also to the two vent control valves 24a, 24b, the drain lines in block or release the compressed air lines 29a and 29b to the working cylinder A. For example, if the right pilot air line 28a with the pilot pressure is applied, the switch valve V gives the compressed air connection to right working space 6 of working cylinder A free. At the same time, since the Pilot pressure in parallel to this also on the right ventilation control valve 24a is placed in a position in which the connection of the left compressed air line 29b released to the atmosphere and this line is therefore depressurized. This also releases the vent valve 27b and the left work space 7 can be vented to the atmosphere. The left bleed control valve 24b is in because there is no pilot pressure the closed position.

Instead of two vent control valves 24a and 24b, as in FIG. 5 shown, a single vent control valve 30 may also be provided, whose two inputs each with one of the two pressure lines 29a and 29b are connected and its exit leads into the atmosphere. The bleed control valve 30 is for example a conventional 3/2-way valve, as well like the switch valve V. If the left control line 28b with the control pressure is acted upon, the compressed air from the compressed air source 25 passes through the Pressure line 29b to the left work space 7. At the same time, the vent control valve due to the control pressure present in parallel in a Positioned in which the right pressure line 29a via the bleed control valve 30 vented into the atmosphere and thus depressurized. In order to the right ventilation valve 27a in the working cylinder A is relieved and the Air can escape from the right-hand work area 6, which is thus a vented counter chamber is to escape into the atmosphere via this valve 27a.

An advantageous embodiment for the switch valve is in FIG. 6 shown. In this embodiment, a rocker valve is used as a switch valve W provided. An essentially rigid, movable about an axis of rotation Seesaw 31 from e.g. Metal is stored in a valve housing 32. The seesaw 31 is for example between two elastomer sealing elements 33 - for higher ones Preferably press reinforced fabric - embedded and and the axis of rotation D pivotable. The housing 32 has at least one supply connection Connection to the compressed air source 25 and two working connections, from which the pressure lines 29a, 29b run out to the working cylinder A. If over the control line 28a applies a pilot pressure of a magnitude that is on the right part of the rocker 31 exerts a force which is greater than that by exerted the supply pressure at P on the right leg of rocker 1 Force, the rocker 31 together with the elastomer sealing elements 33 in the 6 shown position in which the rocker 31 moves the right valve seat closes and the compressed air source 25 via the left working connection via the pressure line 29b with a working space of the working cylinder A combines. The other work connection is closed. Because the control line 28a also applies the control pressure to the ventilation control valve 24a, this opens the connection from the right pressure line 29a to the atmosphere and thus depressurises this line, which also causes the right vent valve Open 27a in working cylinder A and the corresponding working area in can vent the atmosphere.

Particularly small and to achieve a pneumatic work unit The embodiment of the rocker switch valve is made with as few components as possible W of Fig. 6 or 7 advantageous. In the housing 32 is a Insert E with two bleed control valves installed. The control rooms 34a, 34b for the actuation of the rocker 31 are each with a flexible Membrane 35 sealed opening, through which membranes 35 the pressure prevailing in the control chamber 34a, 34b for actuating the sealing elements 36a, 36b of the ventilation control valves is transferred to them, preferably via the valve stems 37a, 37b. From the work ports too The discharge lines 38a, 38b lead the pressure lines 29a, 29b past the rocker 31 to the vent control valves and further to drain openings in the The atmosphere. In the position shown of the rocker switch valve W with Actuation of the left control space 34b with the control pressure would Control pressure also via the membrane 35b and the valve stem 37b the valve element Lift 36b of the left bleed control valve from its valve seat and release the drain channel 38b. The left working connection is in this Position against the compressed air source 25 completed, but is on the Drain channel 38b vented into the atmosphere and thus depressurized. The Right working connection of the pressure line 29a is with the compressed air source 25 in connection and supplies one of the working spaces of the working cylinder Compressed air. The right vent control valve holds the drain passage 38a closed.

Of course, some or all of the elements mentioned can fluid-operated work unit combined in a single component be, which is as far as possible simplification in assembly and Arrange at the installation location. For example, the valve for Control one of the two work rooms or also for double-acting A possible switch valve to control both workrooms directly attached to the working cylinder or integrated into it, preferably in one of the two end pieces of this cylinder. That too or Each bleed control valve can be attached to the working cylinder in the same way and or or the switch valve is attached or even integrated into it his. This eliminates lines between these combined Components and in the case of structural integration also connecting and Sealing points, with which the arrangement of the overall system is essential simplified and its functional reliability - due to the lower risk of Leakages - can be increased significantly. The options just mentioned are also in the design of the switch valve in rocker valve design advantageously applicable.

An expansion of the application possibilities and an increase in the number of possible work processes can be achieved with a very compact arrangement be a control logic arrangement in or on the working cylinder A. is integrated. This can be flanged to the working cylinder or a preferably one of its end pieces can be integrated. From the central Control units go connecting lines to this control logic arrangement in the or on the working cylinder, for communication, electrical control, serve the energy supply and the supply with the working medium. As A fieldbus is preferably provided for the communication system. The Control logic arrangement can also control or position signals of, for example End position or position sensors in or on the working cylinder or from evaluate the actuated elements and take appropriate actions to trigger them control the control valves or these signals and actions via the Report back communication lines to the control unit.

Claims (8)

1. Valve arrangement having a rocker sealing element (31, 33) switchable between two switching positions by the pressure applied to the control connection and having at least one control space (34a, 34b) delimited by the rocker sealing element, characterised by an outlet valve or vent control valve (36a, 36b) which is operatively connected to the control space (34a, 34b) via at least one device (35a, 35b; 37a, 37b) for transmitting the pressure applied to the control connection, there being provided as the device for transmitting the pressure a flexible membrane (35a, 35b) which forms part of the wall of the control space (34a, 34b) and acts, preferably via a valve stem (37a, 37b), on the actual sealing element (36a, 36b), which shuts off or frees the discharge channel (38a, 38b).
2. Valve arrangement according to Claim 1, characterised by an at least functionally identical construction on both sides.
3. Pressure-medium-actuated working unit, comprising at least one pressure source (25), at least one pressure-medium cylinder (A) having at least one discharge opening (12a, 12b) provided with a valve (13a, 13b; 27a, 27b) controllable by the working-medium pressure applied to the supply opening (9a, 9b), at least one valve (V) for the controllable supply of the working cylinder with working medium and at least one line (29a, 29b) for the working medium from the valve to the working cylinder, characterised in that only one line (29a, 29b) each is provided, per working space (6, 7) of the cylinder (A), for the working medium to the cylinder and the lines can be relieved or vented via at least one controllable outlet valve or vent valve (24a, 24b; 30), and in that the discharge opening (12a, 12b) of the working cylinder (A) is kept free.
4. Working unit according to Claim 3, characterised in that the control pressure of the valve (V) is applied to the control connection of the outlet valve or vent valve (24a, 24b; 30).
5. Pressure-medium-actuated working unit, comprising at least one pressure source (25), at least one double-acting pressure-medium cylinder (A), having a discharge opening (12a, 12b), each provided with a valve (13a, 13b; 27a, 27b) controllable by the working-medium pressure applied to the supply opening (9a, 9b), at least one switch valve arrangement (V, W) for the controllable supply of the working cylinder with working medium and at least one line (29a, 29b) for the working medium from the valve to the working cylinder, characterised in that only one line (29a, 29b) each is provided, per working space (6, 7) of the cylinder (A), for the working medium to the cylinder, and in that the switch valve arrangement (V, W) is designed as a valve arrangement according to at least one of Claims 1 and 2.
6. Pressure-medium-actuated working unit according to one of Claims 3 to 5, characterised in that a control logic arrangement, having connections for communication, preferably a field bus, electrical control and supply and for the working medium, is provided in or on the working cylinder (A).
7. Pressure-medium-actuated working unit according to one of Claims 3 to 6, characterised in that the valve (V, W) for controlling one or both of the working spaces of the working cylinder (A) is directly attached to the latter or integrated therein, preferably in one of the two end pieces (2, 3) of this cylinder (A).
8. Pressure-medium-actuated working unit according to one of Claims 3 to 7, characterised in that the or each vent control valve (20, 22; 24a, 24b; 30, 36a, 36b) is attached to the working cylinder (A) and/or the switch valve (V, W) or structurally integrated in the latter.

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