Abstract:
A valve device for influencing a fluid supply of fluid-operated loads, includes a valve module with a valve housing in which valve shafts are formed to accommodate valve cartridges, and further includes valve cartridges located in the valve shafts, wherein each of the valve shafts together with the valve cartridges accommodated therein bounds a pressure chamber connected to an assigned inlet port in a fluidically communicating manner, and wherein each of the valve cartridges includes two electrically selectable valve means which are designed to influence a free flow cross-section between the pressure chamber and an outlet port assigned to the respective valve means.

Description:
This application claims priority based on an International Application filed under the Patent Cooperation Treaty, PCT/EP2012/002788, filed Jul. 3, 2012. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a valve device for influencing a fluid supply of fluid-operated loads. 
     From DE 10 2009 017 877 A1, a valve device is known which comprises a plurality of valve modules lined up in a stacking direction. Each of the valve modules has a plate-shaped passage body with a feed passage recess and/or a vent passage recess, and each comprises four 2/2-way valves, each having a first and a second fluid port. The four 2/2-way valves are interconnected in a full-bridge arrangement. The four 2/2-way valves have an oblong cross-section in a cross-sectional plane parallel to a mounting surface, the main cross-sectional dimension being at least substantially perpendicular to the stacking direction. Furthermore, the main cross-sectional dimensions of the 2/2-way valves of a valve module are oriented coaxially with one another. 
     SUMMARY OF THE INVENTION 
     The invention is based on the problem of providing a valve device which, while having a simple structure, allows a fluid-operated load to be supplied with fluid with a minimum of delay. 
     For a valve device of the type referred to above, this problem is solved by the features of claim  1 . 
     In the solution, it is provided that the valve device comprises a valve module with a valve housing in which valve shafts are formed to accommodate valve cartridges, and further comprises valve cartridges located in the valve shafts, wherein each of the valve shafts together with the valve cartridges accommodated therein bounds a pressure chamber connected to an assigned inlet port in a fluidically communicating manner, and wherein each of the valve cartridges comprises two electrically selectable valve means which are designed to influence a free flow cross-section between the pressure chamber and an outlet port assigned to the respective valve means. 
     In the illustrated embodiment, each of the valve shafts designed as recesses in the valve housing is designed to accommodate one valve cartridge and has a geometry which at least substantially corresponds to the external geometry of the valve cartridges. All of the valve cartridges of a valve device are preferably identical in their external geometry, so that the valve cartridges can be freely selected for installation into the respective valve shafts of the valve module. It is particularly advantageous if the valve cartridges have a constant, in particular rectangular, cross-section along a main dimensional axis. In this way, they can be inserted into the correspondingly shaped valve shafts. The valve cartridges are designed such that each bounds a pressure chamber with the valve shaft. As in the illustrated embodiment, the pressure chamber can be designed as a substantially rectangular volume, adjoining side walls of the pressure chamber being represented by the valve shaft. At least one end face of the pressure chamber is preferably represented by the installed valve cartridge. This results in a simple structure for the valve cartridge, because there is no need for a pressure-tight cartridge housing. On the contrary, it is sufficient if the valve cartridge seals the valve shaft in such a way that the required pressure chamber is formed by the combination of the valve cartridge with the valve module. According to the invention, the pressure chamber has an inlet port which is designed for fluidically communicating connection to a fluid, source or a fluid outlet. This being so, the inlet port can be used either for supplying a pressurised fluid to the pressure chamber or for discharging a pressurised fluid from the pressure chamber. 
     The pressure chamber is further assigned two outlet ports for fluidically communicating connection to fluid-operated loads, such as actuators. Each of the two outlet ports is assigned an electrically selectable valve means designed for influencing a free flow cross-section between the pressure chamber and the assigned outlet port. Using the valve means, the free flow cross-section between the pressure chamber and the outlet port can preferably be adjusted and switched between a blocking position and a release position. In the blocking position, a communicating connection between the pressure chamber and the outlet port is broken, while being completely open in the release position. 
     The valve means are selected by means of an electric control signal provided by a control unit which, as in the illustrated example, can be a part of the valve device or of the valve module, or which is alternatively provided away from the valve device. The control signal may be a DC or an AV voltage or a pulse width-modulated electric signal. 
     Advantageous further developments of the invention are specified in the dependent claims. 
     It is expedient if the valve means in the valve cartridge are movable, in particular pivotable, in a common movement plane between a blocking position and a release position for influencing the respective free flow cross-section to the associated outlet port. By the movable arrangement of the two valve means, a particularly compact design of the valve cartridge can be achieved. If the two valve means perform a linear movement between the blocking position and the release position, the movement axes for the two valve means are preferably oriented parallel to one another in the common movement plane. If the two valve means perform a pivoting movement between the blocking position and the release position, both pivoting planes are located in the common movement plane. 
     In a further development of the invention, an operating port which is formed on the valve housing and which is designed for a fluidically communicating connection to a fluid-operated load is connected in a fluidically communicating manner to an outlet port of a first valve cartridge and to an outlet port of a second valve cartridge for optionally establishing at the operating port a fluidically communicating connection to the pressure chamber of the first or the second valve cartridge. In this context, it may for example be provided that a first pressure chamber, which is defined by a combination of a first valve shaft and a valve cartridge accommodated therein, is set to a first fluidic pressure level and a second, correspondingly designed, pressure chamber is set to a second fluidic pressure level. By coupling an outlet port of the first pressure chamber to an outlet port of the second pressure chamber, the first or the second pressure level can optionally be made available at the operating port by suitable selection of the valve means assigned to the respective outlet ports. As each valve cartridge has two valve means and two outlet ports, two operating ports can advantageously be selected at the two pressure levels with two valve cartridges. 
     Each of the valve means preferably has a first end region located on the valve cartridge and a second end region which is freely movable, in particular pivotable, and which is designed for a sealing contact with a valve seat in the blocking position and for releasing the valve seat in the release position, wherein the valve seat is designed as a terminating orifice of an outlet passage which terminates into the pressure chamber and is connected to an outlet port. In such a configuration of the valve means, the desired pivoting movement is obtained by a curvature of the valve means, which is tongue-shaped in the illustrated embodiment. The firmly clamped end region remains stationary, while the freely movable end region of the valve means can be brought closer to or farther away from the valve seat by altering its radius of curvature. This curvature change can in particular be achieved by introducing an internal mechanical stress, which can be influenced by the applied electric control signal, into the valve means. 
     In a further variant of the invention, it is provided that the valve means are designed as piezoelectric bending transducers. The valve means is preferably a composite of a resiliently bendable substrate material, for example a metal strip, and a coating of a piezoelectric material applied thereto. The pivoting movement of the bending transducer is initiated by applying an electric voltage to the coating of piezoelectric material, which preferably contracts and thereby introduces the desired internal mechanical stress into the valve means. As a result, the latter changes its radius of curvature, resulting in a pivoting movement of the free end owing to the cantilevered arrangement of the valve means. This allows the pivoting movement of the respective valve means to be adjusted precisely by means of the electric control signal provided. The control signal is preferably a part of a control loop, so that the pivoting movement of the valve means and thus the free flow cross-section can be provided as required and matched to the fluid demand of the connected fluid-operated load. 
     At a distance from the first end region, the bending transducer preferably lies on an adjusting means which is supported on the valve cartridge and which is designed for setting a preferred position of the freely movable end region of the bending transducer in the movement plane. Using the adjusting means, manufacturing tolerances of the bending transducer and/or tolerances relating to its installation into the valve cartridge can be compensated, for example. By offering the opportunity for compensating manufacturing tolerances at a later date, the production requirements of the bending transducers and the requirements relating to their installation into the valve cartridge can be restricted to a cost-effective level. The adjusting means is designed for introducing a force into the bending transducer in the movement plane, which force is preferably oriented perpendicular to a surface located opposite the adjusting means, in particular perpendicular to a largest surface of the bending transducer, and which force is preferably directed from the adjusting means towards the bending transducer. This force, which acts at a distance from the clamping point of the bending transducer, can influence the curvature of the bending transducer in such a way that it adopts a presettable preferred position. 
     In a further development of the invention, the adjusting means has in the movement plane a curvature which can be adjusted for adjusting the preferred position of the freely movable end region of the bending transducer, in particular by local energy supply by means of an energy beam. The adjusting means of the illustrated embodiment is a material strip, in particular a metal strip, which is supported on the housing of the valve cartridge and on the bending transducer and therefore allows a force to be introduced into the bending transducer from the housing. At least a section of the adjusting means is curved, and the curvature can be changed by a plastic deformation of the adjusting means for adjusting the force acting on the bending transducer. This plastic deformation can for example be obtained by introducing a force directly into the adjusting means, or alternatively by local heating, in particular by means of an energy beam. Local heating can cause a change in internal material stresses and therefore the desired curvature change. 
     It is expedient if a spring means for providing a pressing force acting on the adjusting means in the movement plane is assigned to the bending, transducer. The spring means ensures a secure contact of the bending transducer on the adjusting means, so that the preferred position of the bending transducer can always be maintained irrespective of the position and/or the operating state of the valve cartridge. The spring means is preferably designed in the form of a leaf spring, in particular as a metal strip, and supported on the housing of the valve cartridge. In a particularly preferred variant, the spring means bears against a surface of the bending transducer which is opposite the adjusting means. 
     It is advantageous if the outlet ports are located on a front end face of the valve cartridge and/or if, adjacent to a rear end face of the valve cartridge, a continuous, in particular rubber-elastic, sealing element is formed for the sealed accommodation of the valve cartridge in the valve shaft. This facilitates&#39; the installation of the valve cartridge into the valve module. In the illustrated embodiment, the outlet ports provided at the front end face of the valve cartridge are arranged on a front wall of the valve shaft while forming a seal in such a way that the fluid can in this region not escape from the pressure chamber between the valve cartridge and the valve module, but is exclusively discharged via the outlet ports. The valve shaft, which is designed for an installation of the valve cartridge by insertion along an installation axis, has along the installation axis a cross-section which is matched to the cross-section of the valve cartridge along the installation axis. The cross-sections of the valve cartridge and the valve shaft are preferably constant along the installation axis, may however alternatively be stepped. In any case, the pressure chamber is preferably bounded in an end region remote from the outlet ports by an end wall of the valve cartridge, which can be sealed and located in the valve shaft by means of the continuous sealing element. 
     In a further variant of the invention, a contact device which is designed for an electric connection between the electrically selectable valve means and, a selection circuit which is in particular designed for configuration in a bus system as a bus subscriber is located on a rear end face of the valve cartridge. In accordance with the illustrated embodiment, this contact device may be a printed circuit board with conductor paths serving as contact surfaces mounted thereon, or a plastic part in MID (moulded interconnect device) technology, wherein electrically conductive areas are applied to the plastic part in an injection moulding process, or else metal pins projecting from the end face of the valve cartridge. The contact device ensures the power supply of the two valve means in the valve cartridge. Sensor means provided in the valve cartridge, if applicable, can also be supplied with electric energy via the contact device and scanned for their sensor signals. The selection circuit can either be located directly in the rear end region of the valve cartridge or is preferably provided for a selection of several valve devices. The selection circuit can preferably be configured as a bus subscriber in a bus system, for example in a field bus system in which data transmission between a higher-order control unit or machine controller and the selection circuit is provided in accordance with a presettable bus protocol. 
     Two each of the valve cartridges are preferably fluidically connected to form two 3/3-way valves. In this way, an advantageous functionality can be obtained for the valve cartridges and the valve module with a minimum of constructive effort. All that is required for providing the two 3/3-way valves is two pressure chambers which are bounded by the respective valve cartridges together with the valve module. Regarding the valve means, the valve cartridges have a uniform structure, which likewise results in a simpler structure and in cost-effective production. 
     The valve device preferably comprises a main valve module having at least one fluidically selectable main valve which comprises a valve member accommodated in a valve chamber and an actuator coupled to the valve member and movably accommodated in a pilot chamber, wherein the pilot chamber is connected to an operating port of the valve module and a position of the actuator and the valve member coupled thereto is adjustable as a function of a pressure applied to the pilot chamber, in order to adjust a free flow cross-section in the valve chamber by means of the valve member. In this configuration of the valve device, the valve module is used for the fluidic selection of the associated main valves, which are in turn designed to influence a free flow cross-section through the respective valve chamber. The valve member of the main valve is preferably movable between a blocking position and a release position for the valve chamber, in order to effect either a complete blocking of the free flow cross-section through the valve chamber or a partial or complete opening of the free flow cross-section. The valve member of the main valve is coupled to an actuator, being in particular integrated therewith, the actuator serving the purpose of introducing a force into the valve member in order to cause its movement. The force introduced is provided by the fluid which is made available by the valve device via the operating port to the pilot chamber in which the actuator is movably accommodated. The actuator is preferably designed in the form of an operating piston which introduces a force depending on the pressure of the available fluid into the valve member. 
     It is expedient if a spring device is assigned to the valve member and/or to the actuator in order to provide a spring force for determining a preferred position of the valve member in the valve chamber. In this case, a pressurised fluid only has to be made available in the pilot chamber if a movement of the valve member out of its preferred position is desired. 
     In a further variant of the invention, it is provided that one valve module and one main valve module each form a valve unit which can be lined up along a line-up axis with an adjacent valve unit with its largest outer surface, wherein at least one recess extending along the line-up axis passes through the valve unit to form a fluid passage. This allows a plurality of valve units to be assembled by simple means to form a compact valve assembly in which a central supply and/or discharge of fluid is/are provided through the at least one fluid passage extending along the line-up axis. The valve units are preferably rectangular, wherein narrow sides which adjoin one another have a smaller width dimension than the side surfaces formed as the largest surfaces and located opposite one another. The edge length of the side surfaces may for example be greater by a factor of 5 to 10 than the width of the four narrow sides, which are oriented perpendicular to one another. 
     It is advantageous if at least one contact means designed for an electric connection of the valve module and/or the main valve module to an electronic selection circuit and/or to an electronic control unit projects at a narrow side of the valve unit. By arranging the contact means on the narrow side of the respective valve unit; the selection circuit provided for a signal transmission between the electronic control unit and the valve means can, in a first embodiment of the valve device, be formed outside the valve unit and nevertheless access the respective valve means directly along a short path. As a result, a structural separation is advantageously obtained between the electrically selectable valve means and the selection circuit, so that the selection circuit can, if faulty, be replaced quickly, or so that the functionality of the respective valve unit can be changed by replacing the selection circuit and/or the device can be adapted to the different requirements of different control units. In a second embodiment of the valve device, the selection circuit is integrated into the valve unit and connected to the electronic control unit via the contact means. In this case, there is no need for a long electric transmission path between the control unit and the selection circuit, because the selection circuit, being integrated into the valve unit, can be brought into direct electric contact with the control unit via the contact means. Generally speaking, as a result of the laterally projecting contact means, the number of electric connection points between the valve means and the control unit is significantly lower than in known valve devices, in which an electric signal transmission is provided along a line-up axis for the valve units and the signals have to be looped through each of the valve units; this has a positive effect on the reliability and on the speed of the signal transmission between the control unit and the valve means. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An advantageous embodiment of the invention is illustrated in the drawing, of which: 
         FIG. 1  is a perspective view of a valve device; 
         FIG. 2  is a perspective sectional view of the valve device according to  FIG. 1 ; 
         FIG. 3  is a perspective sectional view of a valve housing and the valve, cartridges accommodated therein; 
         FIG. 4  is a perspective exploded view of the valve housing; 
         FIG. 5  is a cut top view of the valve housing with the valve cartridges accommodated therein; 
         FIG. 6  is a perspective exploded view of a bottom part of the valve cartridge; 
         FIG. 7  is a perspective exploded view of the valve cartridge; 
         FIG. 8  is a sectional view of the valve cartridge; 
         FIG. 9  is a perspective view of the valve cartridge; 
         FIG. 10  is a pneumatic diagram for a valve module assembled from a plurality of valve cartridges; and 
         FIG. 11  is a sectional view of a main valve. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a valve unit  1  which can be provided as a part of a valve device not shown in detail. The valve unit  1  comprises a valve module  2  and a main valve module  3  connected thereto. The valve module  2 , the structure of which will be described in greater detail later, comprises a valve housing  4 , which is rectangular in the illustrated embodiment. A shorter edge length of narrow sides  5 ,  6  of the valve housing  4  is considerably less than one of the edge lengths of a rectangular side surface  7 . The valve unit  1  has two opposite side surfaces  7 , of which only one is visible in  FIG. 1  because of the chosen perspective. The side surfaces  7  are provided for surface contact with side surfaces of adjacent valve units not shown in the drawing, so that a valve device can be created by lining up several valve units  1 . 
     The main valve module  3 , the structure of which will likewise be described in greater detail later, comprises a main valve housing  8 , which is rectangular in the illustrated embodiment. A shorter edge length of narrow sides  9 ,  10  is matched to the shorter edge length of the narrow sides  5 ,  6  of the valve housing  4 . At right angles to the lateral narrow sides  5  and  9  of the valve housing  4 , contact means designed as tab connectors  11 ,  12  project, the tab connector  11  being electrically assigned to the valve module  2  and the tab connector  12  being electrically assigned to the main valve module  3 . The main valve housing  8  has several recesses  15 ,  16 ,  17 ,  18 ,  19 ,  20 , of which some completely pass through the main valve housing  8  along a line-up axis  21  in order to form fluid passages passing through several or all of the valve units  1  of a valve device not shown in the drawing. In the illustrated embodiment, the fluid passages formed by the recesses  15  to  20  are used to provide a pressurised fluid for the valve modules  2  and/or the main valve modules  3  or to discharge fluid from the valve modules  2  or the main valve modules  3 . 
     The valve module  2  is joined to the main valve module  3  by elastic locking tabs  22  which are formed on a connecting part  23  located between the valve module  2  and the main valve module  3 . The locking tabs  22  have recesses  24  which are matched to locking projections  25 ,  28  on the valve module  2  and the main valve module  3  and which are designed for positive coupling to the locking projections  25 ,  28 . In addition to mechanically coupling the main valve module  3  to the valve module  2 , the connecting part  23  also electrically couples sensor means of the main valve module  3 , which will be described in greater detail at a later point, to a selection circuit not shown in detail, providing the tab connector  12  required for this purpose. The connecting part  23  is preferably designed as an injection-moulded plastic part with integral locking tabs  22 . In a particularly preferred embodiment, the electric connections at the connecting part  21  are produced using MID (moulded interconnect device) technology, i.e. produced in the connecting part  23  by injection moulding. 
     On the narrow side  6  of the valve module  2  which is remote from the main valve module  3 , a further connecting part  29  is located, which is provided for electrically coupling the valve means accommodated in the valve housing  4  to the selection circuit not shown in the drawing and which provides the tab connector  11  required for this purpose. The connecting part  29  has locking tabs  30  which are provided for locking at the valve housing  4 , which is provided with suitably designed locking projections  31  for this purpose. The connecting part  29  is preferably designed as an injection-moulded plastic part with integral locking tabs  30 . In a particularly preferred embodiment, the electric connections at the connecting part  29  are produced using MID (moulded interconnect device) technology, i.e. produced in the connecting part  29  by injection moulding. 
     The sectional view of  FIG. 2  shows the structure of the valve module  2  and the main valve module  3  in greater detail. In the illustrated embodiment, four valve cartridges  32  are accommodated in valve shafts  33  of the valve housing  4 . The valve housing  4  and the valve cartridges  32  accommodated therein will be described in greater detail below with reference to  FIGS. 5 to 9 . 
     In the main valve housing  8  of the illustrated embodiment, four main valve bodies  34  are slidably accommodated in valve recesses  35 . The main valve housing  8  and the main valve bodies  34  accommodated therein will be described in greater detail below with reference to  FIG. 11 . 
       FIG. 3  shows that the valve cartridges  32 , which can be identified as valve cartridges  32 A,  32 B,  32 C and  32 D if required, are rectangular in the illustrated embodiment. As a result, the valve cartridges  32  can be installed into the valve shafts  33 , which can be identified as valve shafts  33 A,  33 B,  33 C and  33 D if required and which can be seen in  FIG. 2 , by inserting them along an installation axis  36 . The valve shafts  32  pass through the valve housing  4  along the installation axis  36  and are at their narrow side  6 , which is provided for contact with the connecting part  23 , sealed by an end plate  37  which can be seen in  FIG. 5 . The end plate  37  is preferably integrated with the valve housing  4 , which is in particular produced as an injection-moulded part. 
     The front narrow side  6  of the valve housing  4 , which is shown in  FIG. 5 , is provided with a plurality of groove-like recessed distributor passages  40 , which can be identified as distributor passages  40 A,  40 B,  40 C and  40 D if required and which are connected in a fluidically communicating manner to openings in the end plates  37 , which are not shown in detail. Each of these openings in turn establishes a fluidically communicating connection between the respective distributor passage  40  and one of the valve shafts  33 . 
     In the illustrated embodiment, it is provided that the distributor passages  40 A and  40 B are connected in a fluidically communicating manner to the valve shafts  22 A and  33 B without initially taking into account the effects of the valve cartridges  32 . It is further provided that that the distributor passages  40 C and  40 D are connected in a fluidically communicating manner to the valve shafts  22 C and  33 D without initially taking into account the effects of the valve cartridges  32 . 
       FIG. 4  shows a header plate  39  which, according to  FIG. 3 , can be mounted on the front narrow side  6  of the valve housing  4  and which is in the illustrated embodiment provided with four operating ports  41 , which can be identified as operating ports  41 A,  41 B,  41 C and  41 D if required, and with a supply port  42 . The header plate  39  can be mounted on the front narrow side  6  of the valve housing  4  to form a seal, thereby ensuring a fluidically communicating connection between a distributor passage  40  and an associated operating port  41 . In the same way, a fluidically communicating connection is provided between the supply port  42  and a supply shaft  43  formed in the end plate  37 . In the illustrated embodiment, a fluidically communicating connection is provided between the supply shaft  43  and the valve shafts  33 B and  33 C. 
     In an embodiment not shown in the drawing, the distributor passages are formed in the header plate together with the operating ports and the supply port. In this way, the end plate of the valve housing can be made simpler, for example featuring only the openings and the supply shaft. 
     In  FIG. 5 , it can be seen how the supply shaft  43  of the illustrated embodiment, starting at the supply port  42 , terminates into the two valve shafts  33 B and  33 C.  FIG. 5  further shows how the valve cartridges  32  bear against the end plate  37  with a front end region. In the illustrated embodiment, the valve means of the valve cartridges  32  of the valve module  2  are—possibly apart from a preferred valve position to be described in greater detail below (normally open—normally closed)—identical in construction, so that they can in principle be interchanged in any way preferred. Each of the valve cartridges  32  of the illustrated embodiment has at a front end face two outlet ports  44 ,  45  which project in the manner of cylindrical end pieces from the front end face of the valve cartridges  32 . Each of the outlet ports  44 ,  45  can be provided with a continuous, preferably annular and in particular rubber-elastic, sealing means  47 , for example an O-ring. In the illustrated embodiment of the valve cartridges  32  and the valve housing  4 , it is provided that two cylindrical recesses  48 ,  49  are formed on an inner surface  50  of the end plate  37  which faces the respective valve shaft  33 . The cylindrical recesses  48 ,  49  are used for the sealed accommodation of the associated outlet ports  44 ,  45  and are in turn connected in a fluidically communicating manner to openings  53  which can be seen particularly clearly in the detail of  FIG. 5 . 
     In the valve cartridge  32  shown in detail in  FIGS. 7 and 8 , the outlet ports  44 ,  45  are integrally formed on a nozzle block  54 . The nozzle block  54 , which is shown in greater detail in  FIG. 7  in particular, has two outlet passages  55 ,  56 , which extend in sections from the outlet ports  44 ,  45  towards the rear end of the valve cartridge  32  and are then kinked at right angles in opposite directions and terminate at contact surfaces  57 ,  58  pointing away from one another, as shown in  FIG. 8  in particular. The termination apertures  59 ,  60  of the outlet passages  55 ,  56  are preferably formed in a valve seat  61 ,  62  projecting from the respective contact surface  57 ,  58  and having the shape of a spherical segment in the illustrated embodiment. 
     The further components of the valve cartridge  32  which can be recognised in  FIG. 5  are explained in greater detail in the context of the description of  FIGS. 6 to 8 . In the illustrated embodiment, the valve cartridge  32  comprises two half-shells  63  which are preferably shaped identically and two individual components accommodated therein and to be described in greater detail at a later point. 
       FIG. 6  shows one of the half-shells  63 , which has a substantially U-shaped cross-section in a cross-sectional plane which is oriented at right angles to the installation axis  36  and is not shown in the drawing. In the production of the valve cartridge  32 , a supporting element  65  designed as an adjusting means can be placed in the half-shell  63  in a first step. In the illustrated embodiment, the supporting element  65  is a bent part made of sheet metal, in particular spring steel. The supporting element  65  has a substantially rectangular contour, a material thickness of the supporting element  65  being significantly less than the largest surface of the supporting element  65 . In a central section, the supporting element  65  of the illustrated embodiment has two notches  66 ,  67  which are preferably mirror-symmetric in respect to a mirror axis not shown in the drawing and by which two supporting webs  68 ,  69  are exposed. These supporting webs  68 ,  69  are curved in the same direction and project beyond the largest surface of the supporting element  65 , which faces the half-shell  63 . In the half-shell  63 , there is formed a reception shaft.  70 , which matches the geometry of the supporting element  65 , being therefore rectangular in the present case, and in which the supporting element  65  can be accommodated in such a way that only the supporting webs  68 ,  69  project beyond the inner surface  72  of the lower half-shell  63 . In the region of the reception shaft  70 , a recess  71  further passes through the half-shell  63  for adjusting the supporting means  65  in a manner to be described in greater detail below. 
     After the supporting means  65  has been installed into the reception shaft  70 , a valve means designed as a piezoelectric bending transducer  75  can be placed in the half-shell  63  in a next assembly step. The bending transducer  75  comprises a substrate  76  which is preferably made of metal and a coating  77  of a piezoelectric material applied to the substrate  76 , for example in a laminating process. At a rear end, the bending transducer  75  is mechanically and electrically coupled to a connecting circuit board  78  which is designed to provide an electric voltage to the coating  77  in order to effect a bending of the bending transducer  75  in a movement plane  80 . At a front end of the bending transducer  75 , which, after its installation into the half-shell  63 , remains free to move in contrast to the rear end, a seal  79  having the shape of a cylinder section in the illustrated embodiment is attached to, in particular bonded to, the surface remote from the lower half-shell  63 . The seal  79  is preferably made of a rubber-elastic material. 
     The coating  77  is preferably designed such that it contracts if an electric voltage is applied. In view of the arrangement of the nozzle block  54  relative to the bending transducer  75 , an increased curvature is accordingly provided if the coating  77  is applied to the surface of the substrate  76  remote from the half-shell  63  as soon as an electric voltage is applied. The bending transducer  75  installed in this way is therefore a normally open (NO) valve means. For a normally closed valve means, the bending transducer  75  only has to be installed in a mirror-symmetric manner, so that the coating  77  faces the half-shell  63 . 
     After the bending transducer  75  has been placed in the half-shell  63 , a leaf spring  81  is placed on the bending transducer  75 . The leaf spring  81  comprises a front hold-down  82  and two rear hold-downs  83 ,  84 , all of which are provided to lie on the largest surface of the bending transducer  75 . The leaf spring  81  further comprises two locking tabs  85 ,  86 , which project laterally in opposite directions and which are designed for a non-positive latching of the leaf spring  81  in the lower half-shell  63 . For this purpose, the half-shell  63  is provided with grooves  87 ,  88  at its lateral legs for engaging the locking tabs  85 ,  86  in the assembly process, so that they are latched in the material of the lower half-shell  63 . By installing the leaf spring  81 , the rear end region of the bending transducer  75  is located on the lower half-shell  63 , while the front end region of the bending transducer  75 , which supports the seal  79 , is brought into a presettable position by introducing a force through the front hold-down  82 . The valve cartridge assembly  89  produced in this way is mounted with a second valve cartridge assembly  89 , which is identical in the illustrated embodiment, as shown in  FIG. 7 . In this process, the nozzle block  54  and a contact block  90  are installed between the two valve cartridge assemblies  89 . 
     The contact block  90  has several conductor paths  91 , which are electrically connected to plug studs  92 . The two valve cartridge assemblies  89  are then connected to one another, preferably by adhesive force, in particular in a welding or bonding process. Next, the electric connections between the connecting circuit boards  78  and the associated conductor paths  91  of the contact block  90  are established in a soldering process, for example using a bow soldering device which can be brought into thermally conductive contact with the connecting circuit boards  78  by means of openings  93  provided for this purpose. In a final step, a seal  94  made of a rubber-elastic material and matched to the cross-section of the valve cartridge  32  and a dimensionally stable seal holder  95  are pushed onto the rear end region of the contact block  90  of the valve cartridge  32 . The seal holder  95  has a recess  96  with a free cross-section which is designed such that the seal holder  95  is positively located on the contact block  90  by press-fitting. In addition or as an alternative, the half-shells  63  and the seal holder  90  can be joined by adhesive force, for example by welding or bonding. 
     In a subsequent step, the function of the assembled valve cartridge  32  can now be tested. In this process, the bending transducers  75  are moved from the neutral position, which is to a great degree determined by the leaf spring  81 , into a functional position by applying an electric voltage to the plug studs  92 . An adjustment of the bending transducers  75  can be performed before and/or after the functional test. This can for example be achieved by directing a laser beam through the recess  71  onto the surface of the supporting element  65 , thereby causing a plastic curvature change of the supporting element  65 . This curvature change alters the supporting force introduced into the bending transducer  75  by the supporting element  65 , so that the preferred neutral position of the bending transducer  75  can be adjusted. 
     When the assembled valve cartridge  32  is now inserted into the associated valve shaft  33 , the sealing contact of the outlet ports  44 ,  45  in the cylindrical recesses  48 ,  49  and the sealing contact of the seal  94  on the outer surface of the valve cartridge  32  and the inner surface of the valve shaft  33  define a sealed pressure chamber  97  as shown diagrammatically in  FIG. 10 . 
     In the embodiment of a valve module  2  shown in  FIGS. 2 and 10 , a connection is provided between the supply port  42  and the two internally located valve shafts  33 B and  33 C. As a result, the respective pressure chambers  97 B and  97 C can be flooded with a pressurised fluid provided at the supply port  42 , and in a pneumatic application the valve means  75  of the valve cartridges  32 B and  32 C are used as ventilating valves. 
     Each of the externally located pressure chambers  97 A and  97 D has in an end region remote from the end plate  37  a discharge passage  100 , which is indicated diagrammatically in  FIG. 10  and which allows fluid to be discharged from the associated pressure chambers  97 A and  97 D into the environment. In a pneumatic application, the valve means  75  of the valve cartridges  32 A and  32 D are used as venting valves. 
       FIG. 9  offers an overview of the assembled valve cartridge  32 , in which the outlet ports  44 ,  45  are already provided with the associated sealing means  47  and the seal  94  and the seal holder  95  are pushed onto and located on the rear end of the valve cartridge  32 . 
     By way of example,  FIG. 10  shows an advantageous pneumatic interconnection arrangement for the valve cartridge  32 . As each of the valve cartridges  32 A,  32 B,  32 C and  32 D comprises two bending transducers  75  and each bending transducer  75  is precisely assigned to one of the outlet ports  44 A,  44 B,  44 C,  44 D,  45 A,  45 B,  45 C,  45 D, pressure can optionally be applied to the operating ports  41 A,  41 B,  41 C and  41 D at a first or a second pressure level. In the illustrated embodiment, in each of the valve cartridges  32  there are provided a first bending transducer  75 - g , which adopts a closed neutral position relative to the associated outlet port  44  or  45  (NC—normally closed), and a second bending transducer  75 - o , which adopts an open neutral position relative to the associated outlet port  44  or  45  (NO—normally open). 
     In the case shown in  FIG. 10 , the outlet ports  45 A,  44 B,  44 C and  45 D are open in the neutral position of the bending transducers  75 , while the outlet ports  44 A,  45 B,  45 C and  44 D are closed in the neutral position of the bending transducers. As the arrangement according to  FIG. 10  provides that the valve cartridges  32 A and  32 D are used as venting valves and designed to discharge pressurised fluid from the respective operating ports  41 , the operating ports  41 B and  41 D are subjected to a venting pressure which may in particular correspond to an ambient pressure for the valve unit  1 . In contrast, the supply pressure provided at the supply port  42  is applied to the operating ports  41 A and  41 C. For this purpose, the bending transducers  75  of the associated valve cartridges  32 B and  32 C are designed such that a communicating connection between the supply port  42  and the outlet ports  44 B and  44 C and the associated operating ports  41 A and  41 C is ensured in the neutral position. In a functional position not shown in the drawing, those bending transducers  75  which are assigned to one of the operating ports  41  are switched, so that for example one or both of the operating ports  41 A,  41 C can be moved from the ventilating position into a venting position and/or one or both of the operating ports  41 B,  41 D from the venting position into a ventilating position. 
     The sectional view of a main valve  101  according to  FIG. 11  shows the main valve body  34 , which is designed in two parts in the illustrated embodiment and which is slidably accommodated in the valve recess  35  of the main valve housing  8 . The main valve body  34  comprises a valve member  102  and an actuator  103  which are permanently joined to one another. For this purpose, a threaded section  104  is provided on the actuator  103  and a corresponding threaded blind hole  105  is formed in the valve member  102 . The main valve body  34  is slidably guided in a valve insert  106 , which is in turn located in the valve recess  35  and which comprises an annular valve seat  107 . As the main valve body  34  is used for influencing a free flow cross-section through a flow passage  108  bounded by the valve seat  107 , a continuous annular sealing washer  109 , which is designed for a sealing contact on the valve seat  107  and thus for blocking the flow passage  108  in the neutral position, is provided between the valve member  102  and the actuator  103 . Both the valve member  102  and the actuator  103  of the illustrated embodiment are sealed against the valve insert  106  by a lip seal  110 ,  111  and therefore define, together with the valve insert  106  and the main valve housing  8 , a pressure chamber  112 . Via a recess  113 , the pressure chamber  112  is connected to a first recess of the group of recesses  15  to  20  according to  FIG. 2 . Via a recess  114 , the pressure chamber  112  is further connected to a second recess of the group of recesses  15  to  20  according to  FIG. 2 . By the interaction between the valve member  102  and the valve seat  107 , a fluidically communicating connection between the recess  113  and the recess  114  along the flow passage  108  can optionally be established or blocked. 
     A compression spring  115 , which in the present case specifies a blocking of the flow passage  108  in the neutral position of the main valve  102 , is assigned to the valve member  102  in an end region remote from the actuator  103 . The opening of the flow passage  108  requires a translational relative movement of the valve member  2  and the actuator  103  coupled thereto along the central axis  116  of the main valve  101 ; in this process, the returning force of the compression spring  115  has to be overcome. For this purpose, the actuator  103  is accommodated in a pilot chamber  118  defined by the valve insert  106  and an end plate  117 . In the end plate  117 , an operating passage  119  is formed through which fluid can be supplied to and discharged from the pilot chamber  118 . For an advantageous seal between the pressure chamber  112  and the pilot chamber  118 , a sealing membrane  120  is inserted between the valve insert  106  and the end plate  117 . If pressure is applied to the pilot chamber  118 , the actuator  103  and the valve member  102  coupled thereto are deflected, thereby lifting the sealing washer  109  off the valve seat  107  and opening the flow passage  108  through the pressure chamber  112 . The pressurised fluid required for this purpose can for example be made available by one of the operating ports  41  of the valve module  2 .