Metering System

Abstract

The present invention relates to a metering system (1) having a housing (2), a piezoelectric actuator (10) located therein, a fluid unit (15) having a valve (16), a plunger device (40) for closing the valve (16), and a transmission lever (20) for connecting the piezoelectric actuator (10) to the plunger device (40), wherein the piezoelectric actuator (10) is arranged within the housing (2) next to and generally parallel to the plunger device (40), the piezoelectric actuator (10) extending substantially in a direction towards the valve (16) and away from the transmission lever (20).

Description

[Technical field]

[0001] The present invention relates to a metering system having a housing, a piezoelectric actuator located therein, a fluid unit having a valve, a plunger device for closing the valve, and a transmission lever for connecting the piezoelectric actuator to the plunger device. [Background technology]

[0002] Metering systems are typically used to meter the material to be metered, typically a liquid to semi-fluid metering substance, in a targeted manner, for example by drop-like or metering point-like release of the metering material by a plunger device through a valve in the metering system, such that, for example, a metering point or "dab" (droplet) can be placed at a location on the workpiece in a single metering step (very simply described in a single opening movement of the plunger device).

[0003] It is moreover often necessary in the so-called "micrometering technique" that very small amounts of metering material or metering substances are applied onto a target surface in a precisely accurate manner and thus in a non-contact manner, i.e. without direct contact between the metering system and the target surface. Such non-contact methods are also often called "jetting methods". Common examples for this are the metering of adhesive dots, solder pastes, etc. during mounting of circuit boards or other electronic components, or the application of converter materials for LEDs.

[0004] From EP 1 414 080 A1, for example, a piezoelectric actuator system or a positioning system with a piezo actuator and an integrated lever transmission is known, in which the piezo actuator extends away from the transmission lever on the side facing away from the valve. This arrangement has the disadvantage that the actuator system is lengthened or has to be inconveniently long in a design-related manner. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT It is therefore an object of the present invention to overcome the disadvantages of the prior art and to present a metering system which is particularly compact. [Means for solving the problem]

[0006] This problem is solved by a metering system according to claim 1 of the appended claims.

[0007] As mentioned in the introduction, the metering system comprises an enclosure, which will be understood to mean both the primarily closed outer casing and the inner structure in which the components located therein are housed in a suitable manner.

[0008] One of these components is the elongated piezo actuator already mentioned in the introduction. This serves to generate a pulse or metering movement that is transferred to a plunger device via a transmission lever to open or close the valve. For this purpose, the piezo actuator can advantageously be fitted into a housing. Here, it can also preferably have an encapsulation, i.e. the actual piezo or piezo stack can be encapsulated to protect it from moisture. An encapsulated piezo actuator can then be cooled more effectively.

[0009] The above-mentioned valves of the fluid unit can in particular relate to so-called "jet valves", thus valves suitable for "squirting" or can operate in a jet manner. With this operating mode, the plunger device serves primarily as a discharge element, i.e. serves for the movement of the plunger towards the valve seat or the sealing seat of the valve, and the metering material or metering substance is squirted out by the plunger. Additionally or alternatively, parts of the plunger device can also function as actual closing elements, which in their functional type close the valve in the course of the metering operation, respectively, by the plunger pressing into the valve seat in its end position. After the release of the desired metered amount, the valve is opened and closed again by simply withdrawing the plunger from the valve seat, when the metering material can also leave the valve and thus be metered due to other forces of the environment, e.g. gravity and / or increased pressure in the valve. Depending on the application, the plunger device can operate here in different functional types, with the plunger of the plunger device serving as a closing element of the valve and / or as a discharge element ("squirting"). Both types of functionality can have practical relevance.

[0010] Furthermore, a transmission lever is accommodated in the housing, which serves to connect the piezo actuator to the plunger device. The transmission lever can likewise be attached to a lever bearing in the housing via a shaft, so that the transmission lever can be tilted relative to the shaft or relative to a tilt axis.

[0011] The shaft can relate to a linear contact bearing or to a roller bearing, as is already known for example from EP 1 414 080 A1.

[0012] The fluidic unit with valve mentioned in the introduction can be configured to be connected, for example, to a housing to supply substantially metering substance to a metering system, so that the metering substance can be expelled by a plunger device through the valve at the desired metering. Except for the portion of the plunger device (as will be further explained below), the fluidic unit substantially comprises all elements useful for supplying metering substance, temperature control, etc.

[0013] The piezo actuator is here arranged substantially next to the plunger arrangement in the housing, in particular aligned with it, the term "substantially next to" meaning that the two components are located close together in spatial terms.

[0014] According to the invention, the piezo actuator extends substantially in the direction of the valve in the direction facing the valve, away from the transmission lever, i.e. the piezo actuator and the plunger device extend next to each other or approximately parallel to each other, within the housing, away from one of the two lever arms of the transmission lever.

[0015] In this regard, for the sake of brevity, it is noted that, hereinafter, without loss of generality, directions towards the valves are also indicated as downward directions, and directions away from the valves, towards the transmission lever, are designated as upward directions. Although a metering system is not shown with metering in this arrangement, relative directional information such as "up", "down", etc. (more of which are listed further below) will therefore be understood accordingly.

[0016] The arrangement according to the invention allows for a particularly compact construction, whereby the metering system as a whole can be significantly shorter than is possible with the solutions known from the prior art: it utilizes the space in the housing in an optimal manner, so that longer components such as elongated plunger devices or piezo actuators do not unnecessarily take up space, i.e. do not increase substantially in terms of length, as was the case hitherto in prior art constructions, for example.

[0017] In addition, the structure according to the invention creates additional space in the length direction, which can be used in such a way that the essential closing part of the entire metering system, i.e. the plunger of the plunger device, which acts as a closing element or a draining element depending on the type of the selected function of the operation of the metering system (as will be explained further below), can be easily and quickly installed for the customer in an interchangeable manner. In addition, although the metering system is originally designed in its construction type for the so-called "normally closed operation", i.e. for the "operation closed in the initial position or metering operation", it can therefore also use components (e.g. plungers and fluid units) that have the same length and are currently available for both normally open and normally closed metering systems. In a normally open or open ("normally open") valve in the de-energized state of the metering system, the closing element is not pressed into the sealing seat in the valve (if no voltage is applied to the metering system), but rather has a short distance thereto. If such a metering system is supplied with power and a metering operation is performed, i.e. the switch is turned on, the metering system is initially operated with voltage so that the closing element is then closed in the initial starting position for the metering operation.

[0018] Here, before each metering pulse, the closing element can be placed on the valve seat of the valve or on the nozzle of the valve, and in the metering operation, it can be raised from this initial starting position to a minimum and then lowered again, so that, depending on the position and the opening duration, the metering substance can be discharged accordingly. In the jet method, the metering substance is additionally ejected, since, as mentioned, the plunger acts as an ejection element and ejects the metering substance when it moves to the valve seat for closing as an ejection element.

[0019] Regardless of the type of plunger function, it is often advantageous if the metering substance has sufficient viscosity so that, thanks to its viscosity, it does not flow or run out of the valve by itself, even when the valve is open. Nevertheless, sometimes it is unavoidable to meter even low-viscosity metering substances.

[0020] In the metering operation, which is closed in the initial starting position, whenever no metering takes place, for example in a switch state where no current flows or in the case of a malfunction or breakage, the closing element is automatically positioned, preferably by a suitably adjusted spring, on the so-called valve seat or sealing seat of the valve thanks to the spring tension. This means that the valve is closed tightly enough by the closing element positioned therein, so that even a very flowable, low-viscosity metering substance cannot escape. This metering operation is therefore particularly suitable for flowable metering substances or when the metering substance is to be metered out of the valve by additional pressure, as mentioned.

[0021] Furthermore, particularly advantageous embodiments and further developments of the invention emerge from the dependent claims and the following description, whereby individual features of the various exemplary embodiments or variants may also be combined into new exemplary embodiments or new exemplary variants.

[0022] Preferably, the transmission lever can extend transversely to the extension direction of the piezo actuator and to the extension direction of the plunger arrangement, meaning that the transmission lever extends transversely in an extension direction extending transversely from the elongated plunger arrangement to the elongated piezo actuator.

[0023] The extension directions of the piezo actuator and the plunger device may preferably be substantially the same.

[0024] By definition, the term "laterally" preferably indicates "almost perpendicular to a line assumed to be the length". In this respect, insofar as the extension direction of the plunger device and the extension direction of the piezo actuator are identical, the term "laterally" is here understood to preferably mean "approximately perpendicular to the extension directions of the two components". Thus, insofar as the extension directions of the piezo actuator and the extension directions of the plunger device are slightly different or close together, these components do not extend completely parallel, and the term "laterally" can also only mean "from one component laterally to the other", thus for example "slightly inclined or at an angle slightly deviating from 90° by a few degrees".

[0025] Therefore, particularly preferably, the transmission lever can extend substantially perpendicular to the extension direction of the piezo actuator and the extension direction of the plunger device.

[0026] With a transmission lever extending laterally, preferably substantially perpendicular to the extension direction of the piezo actuator and the extension direction of the plunger device, the transmission lever maximizes the transmission of the displacement or pulses of the piezo actuator to the plunger device. Thus, as will be explained in more detail below, the piezo actuator can exert an "opening moment" on the plunger device or transmit a force to the plunger device for metering in an energized metering operation via the transmission lever (as far as the configuration of the metering system is concerned, in which the valve in the de-energized state is closed by the plunger device, as defined), which results in a movement of the plunger device away from the valve, and thus a kind of "lifting movement". In addition, when the larger and elongated components extend substantially only in two directions perpendicular to each other, the housing can be configured in a very compact manner, particularly preferably substantially rectangular, and thus protrusions or projections by components extending obliquely thereto can be largely prevented.

[0027] Alternatively or additionally, the piezo actuator can be tensioned against the housing by means of a spring arrangement via the transmission lever by means of a plunger device, whereby at least one spring element, such as for example a pretensioning spring, in particular a compression coil spring, tensions or pretensions the transmission lever directly or indirectly against the surrounding housing of the metering system.

[0028] As already mentioned in EP 1 414 080 A, this provides that the metering system is not relaxed in the event of forces acting on the metering system from outside, so that the components are held together in an appropriate manner.

[0029] The transmission lever can preferably be fitted in a tiltable manner on a tilt axis in the form of the shaft on the side of the shaft facing the piezo actuator, which means that the transmission lever is held between the shaft and the piezo actuator.

[0030] The shaft can likewise be fastened at the end of the lever bearing, preferably on the side facing away from the valve or on the upper side, respectively, which means that the shaft is, for example, mounted non-rotatably and the transmission lever is tilted relative to the non-rotatable shaft.

[0031] Alternatively, for example, a trough can be recessed or formed in the transmission lever on the side of the lever facing away from the piezo actuator, and can for example be pressed in a non-rotatable manner to retain the shaft into the trough. The shaft will then rotate in a lateral opening in the lever bearing.

[0032] Basically, the transmission lever can, for example, have two lever arms that are approximately symmetrical and therefore of at least the same length, i.e. be mounted approximately centrally around the tilt axis.

[0033] The transmission lever can preferably be mounted eccentrically and can be configured asymmetrically, i.e. with a short lever arm and a relatively longer lever arm, as will be described more precisely further below with the aid of preferred exemplary embodiments.

[0034] In the case of a transmission lever having a short lever arm and a relatively longer lever arm, the transmission lever can (to save space) be fitted tiltably, particularly preferably eccentrically, at the end portion mentioned above.

[0035] Here, in order to open the valve, a piezo actuator, preferably in the form of a roller bearing, can be located at a point of actuator engagement at right angles to the tilt axis on the transmission lever, on the long lever arm, close to the tilt axis, whereby the transmission lever can be moved in the direction of an open valve position away from the valve or away from the tight valve seat, with the plunger device being located on the long lever arm, away from the tilt axis, and thus further away from the tilt axis than the actuator engagement point close to the tilt axis, during operation, with the piezo actuator being displaced. The relative terms "close to the tilt axis" and "away from the tilt axis" refer here, respectively, to a point or position in the longitudinal direction of the transmission lever relative to the tilt axis on which the transmission lever is tiltably mounted. The term "close to the tilt axis" simply means a position or point along the longitudinal direction or the above-mentioned transversely extending extension of the transmission lever, as appropriate, which is located closer to the tilt axis than a point away from the tilt axis.

[0036] The plunger device can preferably be formed from at least two rod elements that are tensioned relative to one another. The term "tensioned relative to one another" means that a force is acting on the rod elements that permanently presses them against one another, so that they are in permanent pressing contact.

[0037] Here, the plunger device can particularly preferably have, on the lever side, a transmission element as a first rod element, which in the following preferably functions as a type of "connecting rod", also called "connecting rod" or "conrod", as will become even clearer, and thus performs a movement of a slightly circular path.

[0038] Furthermore, the plunger arrangement can particularly preferably have a closure element on the valve side as a second rod element, which, as is customary in the art, is also called in the following "valve plunger rod" or simply "plunger" for short.

[0039] By the combination of the above mentioned features, it is achieved that the movement of the transmission lever, which, due to its construction, includes both axial and lateral components, is not transmitted directly to the closing element on the valve side of the plunger arrangement, but only indirectly to the closing element via the transmission element on the lever side, since the transmission element is in pressure contact with the closing element or the lever-side plunger head of the plunger. Thanks to the pure pressure contact, and since the closing element can still be guided advantageously mainly axially, in the transmission of the movement of the transmission element, only lateral components are transmitted to the closing element.

[0040] For example, in the de-energized or voltage-depleted state of the metering system, in order to tightly seal the valve by means of the closing element or the plunger tip on the valve side of the plunger on the so-called valve seat or sealing seat in the valve, the valve-side rod part of the plunger arrangement and thus the closing element can therefore perform a purely axial movement, as far as possible without the above-mentioned lateral components, which facilitates that the closing element can be guided or pressed as precisely as possible straight into the valve seat and reduces the risk that sufficient sealing of the valve can no longer be guaranteed, especially for low-viscosity metering substances.

[0041] Furthermore, splitting the plunger arrangement into two rod sections that are tensioned relative to one another assists in characterizing the movement of the connecting rod which minimizes wear of potential friction points between the plunger arrangement and the transmission lever that would otherwise be present in a guide subjected to axial forces, whereas the transmission elements that are in direct contact with the transmission lever can in fact be characterized as such.

[0042] In addition, the valve-side components, which experiments have shown are subject to the most wear, can therefore be replaced alone or separately, without the need for the metering system to be disassembled for this purpose or for the plunger arrangement to be replaced as a whole.

[0043] There are various possibilities for the construction of the spring arrangement.

[0044] The spring arrangement can preferably have several springs or spring elements for spring tensioning of the plunger device. It can, for example, be provided with a spring or spring element on the valve side, i.e. on the side facing the valve in the installed state, or on the side of the transmission lever facing away from the valve, which presses the plunger device against the transmission lever, so that these components are in pressure contact with each other. Additionally or alternatively, it can, for example, have a spring which presses the plunger device into an open valve position, which is located just above the valve seat in the de-energized state of the metering system, i.e. the plunger device does not close the valve of the fluid unit in the de-energized state. As already mentioned above, such a normally open mode of operation of the metering system exists when the metering material in any case, for example, has a corresponding or high viscosity and therefore does not flow out of the open valve opening by itself under gravity.

[0045] However, the spring arrangement may also be configured such that the metering system has a closed valve in the de-energized switch state, i.e. the plunger device or the plunger of the plunger device is pressed against the valve seat. As mentioned, such a normally closed mode of operation of the metering system exists in the case of low viscosity materials that would tend to exit or flow out of an open valve due to gravity.

[0046] Further preferably, the spring arrangement may suitably comprise at least one opening spring arrangement for opening the valve and at least one closing spring arrangement for closing the valve, the closing spring arrangement having a larger spring constant or pretensioning force, e.g. twice as large, relative to the opening spring arrangement.

[0047] Such a spring arrangement results in the valve always remaining closed in the de-energized state because the spring force of the closing spring dominates the opposing spring force of the opening spring. The valve automatically or inevitably begins to open only starting from the point at which the transmission lever at least equalizes the force of the closing spring with the opening spring due to the pulsing of the piezo actuator. That is, when the transmission lever pushes the closing spring away from the valve, the opening spring automatically opens the valve.

[0048] The closing spring arrangement here can simply comprise a single closing spring with a larger or doubled spring constant and / or pretensioning force relative to the opening spring arrangement (which can also have only one opening spring). However, instead of a closing spring with doubled spring constant and / or pretensioning force relative to the opening spring, the spring arrangement can also particularly preferably comprise two, for example substantially identically constructed, closing springs acting in the same direction but opposite to the opening spring, with spring constants and pretensioning rates that are half in a first approximation respectively relative to the single closing spring, but the same relative to the other closing spring. In the following, instead of one closing spring (with doubled spring constant and pretensioning force), which corresponds to a preferred variant, reference will always be made to two closing springs (with half spring constant and pretensioning force). This is not intended to have a limiting effect insofar as at least two closing springs are always required in the following. Basically, unless otherwise stated in this respect below, two closing springs can also always be replaced, if applicable, by a corresponding spring in another position, since a closing spring of twice the strength has, in a first approximation, the same function as two closing springs of half the strength. The advantage of two springs compared to a single one is that they can be used in a more variable manner, in particular in various positions, as will be explained more precisely further below.

[0049] Very particularly preferably, the spring arrangement can comprise two closing springs acting in the same direction but opposite to the opening spring and having in a first approximation approximately the same spring constant and pretensioning force relative to the opening spring, so that almost twice the force of the closing spring opposes a particular force of the opening spring.

[0050] In this respect it will be mentioned that the spring arrangement can basically comprise various types of springs, for example tension springs, wave springs, leaf springs, torsion springs, etc. Particularly preferably, the spring arrangement can comprise a compression coil spring. Possible forms for such compression coil springs or compression springs that emerge in particular are, for example, cylindrical, conical, barrel, waist-shaped compression springs.

[0051] Preferably, the opening spring arrangement, or opening spring (hereinafter the opening spring arrangement will also be referred to in abbreviated form as "opening spring" without loss of generality), as already mentioned above, resiliently engages with the closure element within the housing, such that a force acts on the closure element to move the closure element in the direction of the open valve position.

[0052] Here, the closing spring can elastically tension the transmission element in the housing, in such a way that an at least somewhat greater reaction force acts on the transmission element relative to the opening spring in order to move the transmission element against the closing element and thus in the direction of the closed valve position. As already mentioned above, the configuration of the elastically mounted plunger device allows that components currently available for both normally open and normally closed metering systems (e.g. plunger device and fluid unit) can be used.

[0053] As already described in EP 1 414 080 A1, the spring arrangement of the metering system can here also comprise at least one radially outwardly large compression spring, which surrounds in a space-saving manner at least one of the comparatively smaller already described closing compression springs. By means of said compression spring, also called "pretensioning spring" in the following, it is possible by its function to pretension the transmission lever against the piezo actuator, away from the housing, on a long lever arm distant with respect to its tilt axis, and therefore further away from the tilt axis than an actuator engagement site on the same close to the tilt axis. By pretensioning the piezo actuator, it is achieved that after a displacement, the latter can be returned again to its initial position more quickly.

[0054] In contrast to EP 1 414 080 A1, the transmission lever can be pretensioned or a pretensioning can be set in such a way that the valve is closed with the plunger tip on the valve seat of the valve in the initial, de-energized state of the metering system by at least the plunger tip of the valve-side plunger of the plunger arrangement arranged thereon.

[0055] Various possibilities for further configuration of the plunger device also exist.

[0056] The transmission element of the plunger device may preferably comprise two parts which can be connected to one another. They can be connected in a press-fit manner and / or in a snap-fit ​​manner. For example, the parts can be pressed against one another.

[0057] Alternatively or additionally, the above components may be glued together.

[0058] More preferably, the components can be heat shrunk or joined by heat shrinking.

[0059] Particularly preferably, the transmission element can further comprise the rod part as one part and the head sleeve part as a further part.

[0060] Here, preferably, an elongated, in particular cylindrical, rod part of the transmission element can be located or present on the valve side, i.e. at the end facing the valve in the installed state, and can extend from there to a head sleeve part on the other side of the transmission lever, for example the rod part can extend away from the inclination axis of the long lever arm of the transmission lever, substantially through or exactly past the transmission lever.

[0061] Preferably, the rod portion is guided with some play around it and can extend, guided with some play around it, through a through opening or through bore in the transmission lever.

[0062] Alternatively or additionally, the head sleeve part can preferably have a flange on which the transmission lever is located or is present on the valve side, i.e. on the flange surface facing the valve in the installed state. Particularly preferably, the flange can be located approximately halfway along its longitudinal extension.

[0063] The division of the transmission elements into only a few individual parts, which have little complexity in themselves and which are connected to one another, makes their manufacture as a whole more profitable and also much easier. As already mentioned, these parts can be easily subsequently connected into an interlocking component, for example by means of a thermal press. In an exemplary embodiment, which will be further described later, the transmission lever can axially displace a very precisely guided plunger device against the force of two closing springs, so that it can, for example, press upwards, so that the valve automatically opens or moves into an open valve position due to the reaction force of the closing springs which the transmission lever temporarily overcomes or overcomes due to the force of the opening springs.

[0064] There are also favorable possibilities for the arrangement of the plunger device in the housing.

[0065] The rod part of the transmission element can be guided axially, preferably with a relatively narrow radial play, parallel to the piezo actuator, in the first housing sleeve part of the housing sleeve of the housing. This means that the rod part of the transmission element on the valve side close to the transmission lever, i.e. here in the area near the bottom of the transmission lever, can be guided essentially axially, although it can move slightly radially and laterally in relation to the cylindrical rod of the rod part in the housing sleeve. The rod part therefore moves as much as possible only axially in a straight line, without any significant lateral movement, away from the valve seat, away from the valve or into the valve seat, into the valve.

[0066] In contrast, the head sleeve part of the transmission element facing away from the valve can be guided with a relatively wide radial play, which allows a slight lateral movement or respectively a circular path movement of the head sleeve part, which occurs through a contact point against the transmission lever remote from the tilt axis and to which, as already mentioned many times, a pulse or a kind of "torque" is transmitted by the piezo actuator close to the tilt axis. The head sleeve part therefore acts like a kind of connecting rod, as will be explained in more detail below.

[0067] That is to say, the head sleeve part on the other side of the transmission lever as seen from the valve, therefore here at the top, is almost completely unrestricted in its radial movement and can therefore perform a maximum range of movement almost freely, i.e. at least in so far as it can move within the range of possible movements of the rod part which is closely axially guided relative to it on the valve side, therefore here at the bottom. This means that it is limited in any case by the length of the rod part to a very small lateral movement or range of movement. This is because if the head sleeve part is moved too far laterally, the rod part directly abuts on its axial guide around nearby at the bottom and thus prevents further lateral movement or lateral displacement (or radial movement) of the head sleeve part.

[0068] Preferably, one of the closing springs of the spring arrangement, in particular a small compression coil spring surrounded by a large compression coil spring, can be located or present in the head sleeve part on the side of the flange facing away from the valve.

[0069] The transmission element or the head sleeve part of the transmission element can thus be tensioned between the housing and the closure element without directly contacting said lever. In addition, as the closure spring is accommodated inside and thus in the unused area of ​​the pretensioning spring of the piezo lever system, this arrangement saves space and therefore does not unnecessarily lengthen the plunger device of the metering system.

[0070] The flange of the head sleeve part can have, on the side facing the valve, hemispherical protruding spherical shells for low-wear interlocking between the transmission lever and the plunger arrangement on the valve side in the intended installed state, which can form a bearing together with a corresponding, particularly preferably recessed, spherical cap formed for this purpose on the transmission lever.

[0071] Since the surface of the spherical shell in the spherical cap undergoes a slight, particularly frictionless, rolling movement, the bearing is also referred to as a "roller bearing" in the following, whereby an almost frictionless transition is formed between the slight circular path movement of the head sleeve part or the movement of the connecting rod and the axial movement of the rod part.

[0072] Particularly preferably, the spherical shell in the flange of the head sleeve part can be configured in the form of a hemispherically recessed spherical cap into which the sphere is pressed, which facilitates manufacture since the formation of one of the components, a hemispherically protruding spherical shell, can be omitted.

[0073] Most particularly preferably, the flange of the head sleeve part can be provided with a bearing block behind the contact point where the closing spring is located. The bearing block can, for example, again be in the form of a rectangular parallelepiped (block-shaped chordal rectangle) on the flange and can further protrude on the round flange in the direction towards the transmission lever and away from the closing spring. Such an additional bearing block on the round flange has the advantage that it provides a space for forming or recessing the spherical cap therein. In order to receive the two spherical cap recesses or the spherical cap of the transmission lever in a low-wear manner, the bearing surface of the bearing block can be provided in itself with a hemispherical recessed spherical cap, in which a sphere is pressed and on which the spherical cap of the transmission lever can roll.

[0074] By doing this, the "interlocking" produced with the spherical cap on the transmission lever via the sphere pressed into the head sleeve is only "loosened" in the closed state of the valve when the plunger or closure element is slightly lifted out of the transmission lever through the nozzle in the valve or the valve insert.

[0075] There are also various possibilities for further configuration of the metering system.

[0076] Preferably, a first permanent magnet can be fastened to the plunger arrangement, preferably to the head sleeve of the transmission element, for example on the front end of the plunger arrangement remote from the valve.

[0077] Particularly preferably, the permanent magnet can therefore be fastened, more precisely, to the end of the plunger device on the head sleeve part of the plunger device in the intended installed state, or to the end of the head sleeve part of the plunger device which faces away from the transmission lever.

[0078] Here, preferably, a Hall sensor can be arranged opposite this permanent magnet in the housing and spaced apart by a gap, which can conventionally be arranged, for example, on a board for controlling the metering system or the like, located above the plunger device, more precisely above the front end of the head sleeve part of the plunger device.

[0079] By means of the above-mentioned permanent magnet and Hall sensor, the position of the plunger device relative to the valve or relative to the nozzle can be measured and then adjusted accordingly. Here, for example, a standardization table can display the correlation between the voltage change of the Hall sensor and the existing distance change. First, before the adjustment of the correct position of the plunger device relative to the nozzle, the head nozzle part of the transmission element of the plunger device is located at or on the transmission lever, in which case the plunger tip of the plunger does not yet close the nozzle or the valve without directly contacting it in the normally closed valve position. To adjust the appropriate position of the plunger relative to the nozzle, the nozzle is moved in the direction of the plunger until a defined change is detected by the above-mentioned permanent magnet and Hall sensor, thus resulting in a defined lifting of the head sleeve part, in particular the spherical shell, from the transmission lever, from the spherical cap of the transmission lever. For this, the distance between the nozzle and the plunger tip is reduced by rotating the adjustment nut until the desired voltage change can be detected via the Hall sensor. This desired position can then also be continuously monitored during operation.

[0080] More precisely, the distance between the nozzle insert and the plunger at the beginning of the adjusting process or "adjusting process", which will be further described later according to an exemplary embodiment, is generated by the connecting nut or (nozzle) adjusting nut being rotated until it is in its lowest adjustable position (maximum distance between the nozzle insert and the plunger). This adjusting routine or "adjusting routine" is started, and the distance is first reduced and finally raised over the nozzle insert until the display in the control unit indicates that the desired position (slightly raised from the lever) has been reached.

[0081] As a result, during operation, it is possible to constantly monitor whether the components of the lever movement change without entrainment of the plunger (the gap created by the slight lifting during the adjusting or regulating process) and / or whether the voltage of the Hall sensor changes in the closed state and / or how large the total change of the Hall sensor signal is relative to the desired or expected plunger movement. Here, too, if necessary, the control signal can be configured such that said movements still remain equal and therefore stable even in the case of wear. Thus, necessary user involvement during operation can be prevented for as long as possible, which for example increases the productivity of the machine and reduces maintenance times.

[0082] Preferably here, for example, a smaller second permanent magnet can be arranged on the side of the Hall sensor facing away from the first permanent magnet.

[0083] Preferably, here the second permanent magnet can be provided with an opposite magnetic field opposite to that of the first permanent magnet.

[0084] The measuring range of the Hall sensor, which is always divided symmetrically around the zero point, can therefore advantageously be shifted so that a larger, complete measuring range is available and thus has a greater sensitivity, since the Hall sensor can no longer measure only in the positive range and only in the negative range, but rather its measuring range is at least partially, preferably completely, shifted into the negative range or, depending on the polarity of the magnetic field, into the positive range and thus increased.

[0085] Alternatively or additionally, the surrounding area around the Hall sensor, which particularly preferably includes a second permanent magnet, can be magnetically protected by a shield, at least on the side facing away from the first permanent magnet.

[0086] The side facing away from the first permanent magnet means that the shield can be advantageously opened towards the first permanent magnet at least on one side, so that the head sleeve part with the first permanent magnet can be moved into the shield at least on this side, and the influence of possible external magnetic fields on the remaining side can be blocked. For this purpose, the shield can be configured, for example, with an approximately rectangular parallelepiped shape or using a rectangular parallelepiped housing.

[0087] Alternatively or additionally, the shield can consist of a cuboid-shaped component, a flexible magnetic lever bearing and / or a flexible magnetic component inserted into said lever bearing in the direction of the valve, in particular when said lever bearing is made from a more advantageously stable material, such as for example aluminum, that does not act in a sufficiently magnetically protective manner by itself but does provide the necessary stability.

[0088] Advantageously, the above-mentioned upper area above the board and the frame area surrounding the piezo actuator can be made from non-magnetic materials in order to make them more advantageous and lighter to design. Generally, measurement errors can be practically prevented by shielding or interference factors that may affect the measured magnetic field are minimized.

[0089] As already mentioned above, the plunger device is guided at least inside in a section in the housing sleeve, which can preferably be adjustably mounted in place from the outside by means of a spring which can be tensioned by means of a nut to the surrounding housing of the metering system in order to adjust the distance between the valve and the closure element (also commonly referred to as the "nozzle-plunger distance"), which can be very easily adjusted by the customer by means of this nut, and can also be adjusted to a very precise value, for example in the simplest case manually, for example by means of the above-mentioned measurements with permanent magnets and Hall sensors.

[0090] Preferably, the transmission lever can be configured and arranged such that in a de-energized starting position of the piezoelectric actuator, the plunger arrangement is tensioned against the piezoelectric actuator via the transmission lever such that an actuator engagement point of the piezoelectric actuator close to the tilt axis of the transmission lever lies on a line or plane containing the roller bearing surface of the shaft of the tilt axis relative to the transmission lever and the spherical shell of the flange of the head sleeve portion of the spherical cap remote from the tilt axis of the transmission lever.

[0091] The piezo actuator in the starting position therefore has the advantage of engaging at the height of the tilt axis and at the height of the contact point with the plunger arrangement of the transmission lever.

[0092] For example, on the one hand, the piezo actuator can be supported rigidly on the valve side via a surface contact, and on the other hand, it can be tensioned by a linear actuator engagement point parallel to the surface contact on the lever side close to the tilt axis on the long lever arm of the transmission lever.

[0093] Preferably, the closure element can be advantageously installed in the metering system, particularly preferably together with the fluid unit, directly by the customer himself, removable in the sense of replaceable, most particularly without the use of tools. This means that the closure element can simply be connected to the transmission element, for example under pressure, or can be contacted, so that it can be changed or replaced by the customer himself very easily and quickly, particularly without the use of tools. Installing the closure element in such a replaceable manner in the metering system is therefore particularly advantageous, since the service life of the metering system as a whole is improved, when it is the component of the metering system that is exposed to the greatest wear during operation of the metering system.

[0094] The invention will be explained again in more detail below with the aid of exemplary embodiments and with reference to the accompanying drawings, in which like components are given the same reference signs in the various figures and which are generally to be understood as merely schematic illustrations, not to scale. [Brief description of the drawings]

[0095] [Figure 1] A longitudinal cross-section through an exemplary embodiment of a metering system according to the present invention with the fluid unit not connected and the plunger removed, looking into the interior of the partially open housing shown. [Diagram 2]FIG. 2 is a schematic side view on the exemplary embodiment of FIG. 1 with the most essential components for the metering mechanism (but not the housing for clarity), with the plunger attached and the fluid unit connected. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0096] These figures show an exemplary embodiment of a metering system 1 according to the invention. Among the main components of this metering system 1 are a housing 2 with a piezo actuator 10 located therein, a fluidic unit 15 (see FIG. 2) with a valve 16, a plunger device 40 for closing the valve 16, and a transmission lever 20 or lever 20 for connecting the piezo actuator 10 to the plunger device 40.

[0097] In general, the housing 2 of the metering system 1 can be described as being approximately rectangular cuboid in shape. Figure 1 shows here a longitudinal section of the metering system 1 without a fluidic unit (not shown in Figure 1) connected to it. Figure 2 shows, inter alia, how and where the fluidic unit 15 of the metering system 1 is connected to the rest of the metering system 1.

[0098] In this respect, at the lower corner (here on the right), the housing 2 has, on the underside, a connection point for an elongated closure element 51 or plunger 51 of the plunger device 40 and for a fluidic unit 15 with the valve 16. The closure element 51 or plunger 51 is part of the fluidic unit 15 or is mounted in the latter and can be replaced together with it when replacing the fluidic unit 15.

[0099] As can be seen in Fig. 2, in the intended connected state, the plunger 16 sits on the valve 16 in a so-called valve seat or sealing seat. In this position, it closes the valve 16 as required, so that the metering material cannot flow out or exit unintentionally from the valve 16. In this respect, it is once again mentioned that the metering system 1 in operation is generally mainly used in the orientation shown in Fig. 1, i.e. metering on the workpiece is mostly performed by means of gravity and thus in the metering direction DR, thus downwards, for example from the lever 20 to the valve 16, and that the relative directional information such as "top", "bottom", "up", "down", "upper", "lower", "side or left / right", "horizontal", "vertical", "front", "rear", etc., here refers arbitrarily to the illustrative examples in the figures, as in the entire document.

[0100] At the top, in the opposite (here left) upper corner of the housing 2, several cables or lines leave the housing 2, via which the metering system can be connected to a higher-level control unit (not shown here) for control, current supply etc., the latter likewise being connectable to the higher-level metering system.

[0101] Within the housing 2, a cylindrically encapsulated piezo actuator 10 is located in the lower half at the center, as will be explained further below. The latter is mounted underside at its rear end on a flat surface contact 5 of the housing 2 with a planar or flat support surface 14 and is electrically connected via a through contact bore. Through this mounting, losses in the mounting area can be minimized. At the opposite upper end, the piezo actuator 10 has a trapezoidal actuator front part 11 extending to a lever 20 located above it, which forms a roller bearing 24 on a cylinder pin 24z extending laterally or horizontally through the lever 20 and sinks into the lever 20 to seat or engage at an actuator engagement point 24 inside the lever 20. The cylinder pin 24z is here pressed firmly into the lever 20, so that the piezo actuator 10 with its actuator front part 11 is configured on the front side like a jaw or concave relative to the cylindrical outer surface of the cylinder pin 24z, and when it is stretched upwards or compressed again downwards in the opposite direction, so that by applying a voltage, a pulse is exerted on the lever 20, the piezo actuator 10 can roll slightly laterally on the cylinder pin 24z, thus here to the right or left.

[0102] Here, the piezo actuator 10 itself is a hermetically encapsulated piezo actuator 10, i.e. it comprises a piezo stack surrounded by a "wavy" encapsulation 12 of the piezo actuator 10 apart from a line guided through the encapsulation 12, which is surrounded in a hollow cylindrical shape with some play by the housing 2. Annularly around the upper side of the piezo actuator 10 below the actuator front part 11, a ring seal 13 seals between the encapsulation 12 and the housing 2, thus forming an intermediate space around the encapsulation 12 in which a cooling fluid can circulate around the encapsulation 12 to cool the piezo actuator 10 during operation. For this purpose, this cooling fluid is advantageously introduced continuously in a cold state into the intermediate space on one side and discharged again in a warm state on the other side (not shown here), so that the piezo actuator 10 does not exceed a certain maximum operating temperature in any case.

[0103] As already mentioned, the lever 20 is located above the piezo actuator 10. This lever is mounted in the housing 2 via a cylindrical shaft 4 which extends laterally (here into or out of the plane of the drawing) horizontally relative to the lever 20, such that it can be tilted about the shaft 4 or tilt axis R, which shaft exhibits or realises the tilt axis R.

[0104] For this, the shaft 4 is clamped or seated firmly and end-wise on the lever bearing 3 or, respectively, in the lever bearing part of the housing 2, which surrounds the lever 20. The lever 20 is pressed or tensioned from below against the shaft 4 by the pretensioning spring 67 of the spring arrangement 60 and the piezo actuator 10. In the starting position it is therefore aligned approximately horizontally.

[0105] A very short lever arm 21 extends from an eccentric or off-centre position of the shaft 4 or tilt axis R in the longitudinal extent of the lever 20 (here to the left in the longitudinal section in FIG. 1 ) and a long lever arm 23 extends in the opposite direction (here to the right) with respect to it. The short lever arm 21 serves only as a bearing 22 or trough for the shaft 4, so that the eccentrically arranged shaft 4 is, so to speak, located approximately at one end of the lever 20, but cannot slip onto the side of the short lever arm 21 on the lever 20.

[0106] The long lever arm 23 has an actuator engagement point 24 of the piezo actuator 10 near the tilt axis, and thus near the position of the shaft 4, and a plunger contact point 25 away from the tilt axis, and thus at the end portion of the lever arm 23. At the plunger contact point 25, the lever 20 engages a plunger device 40 - a sort of "shovel" with a "hole" 28 or through opening 28 in the shovel surface surrounding the inner edge of the hole 28 - in its extension direction E. 20 It can be received or lifted approximately perpendicular to the surface.

[0107] The pretensioning spring 67 already mentioned above, here a large compression coil spring 67 having a larger inner diameter relative to the hole 28, means a pretensioning of the lever 20 against the piezo actuator 10 around the hole 28 on the upper side of the shovel face of the lever 20, along the hole edge 27 of the hole 28 or at the pretensioning contact point 27.

[0108] The plunger device 40 is arranged in the extending direction E of the piezoelectric actuator 10 in the housing 2. 10 An extension direction E approximately parallel to 40 Then, very close to the piezo actuator 10, through the hole 28 of the lever 20 (in the extension direction E of the lever 20) 20The illustrated arrangement is particularly compact, since the piezoelectric actuator 10 and the plunger device 40 therefore extend in the same extension direction E 10 , E 40 2, are arranged substantially vertically adjacent to one another in a particularly compact manner in the housing 2 and are here connected to one another via relatively short levers 20, thus merely spaced apart from one another by a small distance.

[0109] At the plunger contact point 25, the lever 20 directly engages beneath the plunger device 40 and lifts it (here from below in the opening movement of the valve 16, as will be explained in more detail below), but the plunger contact point 25 has a surface with two concave spherical caps 26 which, as will be explained in more detail below, receive corresponding spherical shells 49 of the plunger device 40 in a so-called interlocking manner.

[0110] The plunger device 40 itself consists here of two rod elements 41, 51 which, in the ready-for-operation state of the metering system 1, are tensioned relative to one another by the already mentioned spring arrangement 60. In this ready-for-operation state, the hydraulic unit 15 is connected to the housing 2 of the metering system, as is the case in FIG.

[0111] The first (here upper) rod element 41 or transmission element 41 of the plunger device 40 then consists of two separately manufactured parts 42, 45, namely an elongated rod part 42 having a rod with a cylindrical outer surface and an elongated head sleeve part 45 having a hollow cylindrical cylinder body and a wider head. The two parts 42, 45 are pressed against each other for mounting, i.e. the rod part 42 is fixed at its end part inside the hollow cylindrical head sleeve part 45 by a customized fastening method, namely heat shrinking.

[0112] For the mating connection with the head sleeve portion 45, the rod of the rod portion 42 has a radially outwardly projecting annular groove or flute 43 on its outer surface in the region of the end portion which is introduced or inserted internally into the head sleeve portion 45.

[0113] Correspondingly, the head sleeve part 45 of the transmission element 41 has a radially inwardly projecting annular spring 46 which, in the connected state of the two parts 42, 45, engages at least slightly in a mating manner into the annular grooves 43 or flutes 43. The annular grooves 43 and the annular springs 46 of the two parts 42, 45 can also alternatively be associated with corresponding internal and external threads which can be screwed into each other to connect the two parts 42, 45 to each other in a mating manner.

[0114] The head of the head sleeve part 45 constitutes a flange 47 which is wider with respect to the remaining head sleeve part 45. The flange 47 has two different surfaces 47a, 47b when viewed in the axial direction of the head sleeve part 45. On the valve side (when viewed in the axial direction) it has a first flange surface 47a which is formed by a rectangular parallelepiped bearing block 48. Facing away from the valve it has a second flange surface 47b which is circular disc shaped.

[0115] A closing spring 64b or one of the smaller compression coil springs 64b (additionally described further below) of the spring arrangement 60 for closing the valve 16 is located at the rounded flange surface 47b facing away from the valve. The compression coil spring 64b annularly surrounds the cylinder body inside the head sleeve part 45.

[0116] At the rear side, i.e. at the valve side, the bearing block 48 projects flange-like, here in the form of a "chordal rectangle", from the second flange surface 47b facing away from the valve, with respect to the circular disk-shaped flange surface 47b. It has two spherical shells 49 (already mentioned above) which project hemispherically in the direction of the lever 20. These roll during operation on corresponding spherical caps 26 (also already mentioned above) which are formed or recessed in the lever 20 at the plunger contact point 25. The head sleeve part 45 of the plunger arrangement 40 is thus, so to speak, interlocked with the lever 20, forming a friction point of low friction.

[0117] The second rod element 51 (here, lower in FIG. 2) or closure element 51 of the plunger arrangement 40, also referred to below as “plunger 51”, is of one-piece construction. It has an elongated cylindrical body or shank which is formed with a plunger tip 52 at its lower end (the end facing the valve 16 in the intended installed state) and with a plunger head 53 at its opposite upper end. The plunger head 53 is associated with an annular flange, and thus with an annular extension or ring, which has a wider outer diameter than in the remaining body or shank of the plunger 51. The plunger tip 52 is here associated, for example, with a rounded front part of the plunger 51. However, the plunger 51 can also be associated with a so-called “valve pushrod”, as specifically described in DE 10 2020 121 777 A1, differently from the one illustrated here. In this regard, the contents of which are incorporated herein.

[0118] At the upper side, ie on the lever side of the plunger 51 , the transmission element 41 already mentioned above is located on the plunger head 53 .

[0119] In this respect, it will be mentioned that the housing 2 has here a slightly elliptical discharge opening 2d in the region of the plunger head 53 of the plunger 51 or almost at the level of the plunger head 53 of the plunger 51, as can be easily seen in Fig. 1. In case of leakage of the metering material to be metered, this provides that the metering material cannot reach or be pressed into the drive area of ​​the metering system 1 located above the plunger 51 from the nozzle chamber of the fluidic unit 15 located below in the region of the plunger tip 53, but can already flow out of the metering system 1 beforehand from this discharge opening 2d at an advantageously selected point of the metering system 1. At the same time, the size of the discharge opening 2d allows a simple and therefore easy visible optical check of this area.

[0120] As already partially described, the plunger devices 40 are resiliently mounted on themselves or tensioned with respect to each other by the spring arrangement 60. To this end, the spring arrangement 60 comprises on the one hand three smaller compression coil springs 61, 64a, 64b which are substantially identical in construction and have substantially the same outer diameter, the compression coil springs 64a, 64b constituting the closing spring arrangements 64a, 64b and the compression coil spring 61 constituting the opening spring arrangement 61.

[0121] Two of the compression coil springs 64a, 64b or closing springs 64a, 64b are arranged such that their elastic force urges the plunger device 40 towards the valve 16 by ultimately pressing the plunger 51 of the plunger device 40 into the so-called closed valve position into the valve seat in order to close the valve 16.

[0122] The lower of the two closing springs 64a, 64b is here arranged above the plunger head 53 of the plunger 51 within the second housing sleeve part 8 of the housing sleeve 6 of the housing 2 and acts indirectly from above via a guide sleeve 8f on the plunger head 53 of the plunger 51. Here, the closing spring 64a surrounds with play the shank or cylindrical body of the rod part 42 of the transmission element 41 and is supported at its upper side with a relatively narrow play around the shank of the rod part 42 against a limiting part 66a or edge 66a of the first housing sleeve part 7 of the housing sleeve 6 located adjacent thereto, in which the plunger device 40 is mounted.

[0123] The transmission element 41 is additionally pressed downwards in the direction of the valve 16 and against the closing element 51 by the upper of the two closing springs 64a, 64b, which is in fact, as already described, mounted above the flange 47 of the head sleeve part 45 and bears above it on the part 66b of the housing 2.

[0124] The third remaining (smaller) compression coil spring 61 or release spring 61 is positioned directly below the plunger head 53 of the plunger 51 and is pressed against the plunger head 53 by being supported at its lower end against a guide sleeve 63 which axially guides the plunger 51 when it is connected to the remainder of the metering system 1 together with the fluid unit 15 and valve 16, substantially as shown in FIG. 2.

[0125] Thus, in total, the two compression coil springs 64a, 64b press downwards and the one compression coil spring 61 presses upwards, so that the valve 16 is simply closed due to a force imbalance in the normal, i.e. de-energized state of the metering system 1.

[0126] When the operating lever 20 then presses the head sleeve part 45 by the pulse of the piezo actuator 10 and moves the latter together with the rod part 42 away from the valve 16 against the pressure of the closing springs 64a, 64b of the spring arrangement 60, it somewhat frees the plunger 51 located below it in the closed valve seat. Through the elastic force of the closing springs 64a, 64b now assumed by the lever 20, there is temporarily no elastic force against the opening spring 61, or at least a smaller elastic force against it, so that the opening spring 61 can push the plunger 51 up from the valve seat into the open valve position.

[0127] In addition to the spring arrangement 60, the metering system 1 also has a connecting spring 70. For example, when a fluidic unit 15 with the desired valve 16 and with a suitable plunger 51 (which may be part of the fluidic unit 15 as mentioned) is attached to the remaining metering system 1, this serves the possibility of manual adjustment of the nozzle-plunger distance by the customer. For this, in order to connect the fluidic unit 15 to the remaining metering system 1, the metering system 1 has a connecting nut 18 in the fluidic unit 15, which can be screwed into a thread 9 in the fluidic unit 15 or in the housing sleeve 6 of the housing 2. The connecting nut 18 can now be tightened against the elastic force of the connecting spring 70, and thus the nozzle-plunger distance can be adjusted more precisely. For this, the connecting spring 70 has an inner diameter that is larger than the outer diameter of the first housing sleeve part 7 and smaller than the outer diameter of the second housing sleeve part 8, in particular approximately the same in size. The connecting spring 70 is located on the upper side of the second housing sleeve part 8 and on the connecting nut 18 above. It therefore fits around the first housing sleeve part 7 and rests on the second housing sleeve part 8 below in the direction of the valve 15. In the connecting part of the connecting nut 18 above the connecting spring 70, this is sealed at two points, above and below, by two ring seals 19, so that no fluid, e.g. metering material, can penetrate into the parts of the housing and therefore in particular the frame which surrounds or receives the piezo actuator above it.

[0128] Furthermore, the metering system 1 also comprises a fluid positioning portion 17 for positioning the fluid unit 15, which is selectively heatable by a corresponding control. This serves to heat the metering material, the fluid unit 15 with the valve 16, and / or the plunger 51 in the valve 16.

[0129] At the opposite upper end of the housing 2 of the metering system 1, located above the plunger device 40 tensioned by the spring arrangement 60 relative to one another, a magnetic shield 80 is located as part of the housing 2. The magnetic shield 80 magnetically protects, outwardly, in particular upwardly, a Hall sensor arrangement having a first permanent magnet 81, a Hall sensor 82 spaced therefrom by a gap 84, and a second permanent magnet 83 above the first permanent magnet 81.

[0130] Also to magnetically protect the Hall sensor arrangement downwards, the part of the housing 2 in the area of ​​the lever bearing 3 serves as a further magnetic shield below the magnetic shield 80. Overall, the Hall sensor arrangement is thus protected against external influences, so that the Hall sensor can perform measurements as accurately as possible without being disturbed. This is because the Hall sensor serves to adjust the plunger-nozzle distance very precisely and also to monitor it during operation as a kind of "feedback system". Thus, during operation, the movement of the plunger can be correlated with the control voltage, and if applicable, the control voltage can be readjusted or a warning message can be generated, for example, when the measured value is outside a predefined target range and, for example, an operator's intervention is required. This is achieved by the distance between the Hall sensor 82 and a first permanent magnet 81, which is inserted into the upper sleeve end of the head sleeve part 45 as a small rod-shaped permanent magnet 81, which is detected by the Hall sensor 82 in the form of an absolute magnetic field measurement. When a determined value is measured, the ideal desired distance or gap 84 is present. The plunger 51 is thus located at the other end of the plunger arrangement 40 in the desired position and thus at the desired plunger-nozzle distance with respect to the valve 16 or with respect to the nozzle 16. The second permanent magnet 83 is arranged above the Hall sensor 82 on the side of the Hall sensor 82 facing away from the first permanent magnet 81, with its magnetic field acting opposite to that of the first permanent magnet, the second permanent magnet 83 serving to shift the magnetic field so that the measuring range of the Hall sensor 82 is fully utilized. This means that, in order to increase the sensitivity of the Hall sensor 82, the measuring range of the Hall sensor 82, which is usually divided into a positive range and a negative range, is shifted as completely as possible into the positive range or into the negative range.

[0131] Finally, it is pointed out once again that the above detailed description of the device only relates to an exemplary embodiment, which a person skilled in the art can modify in various ways without departing from the scope of the invention. For example, several metering systems can be arranged in a metering system. Furthermore, the use of the indefinite article "ein" or "eine" does not exclude that there can also be a plurality of the respective features. [Explanation of symbols]

[0132] 1. Metering System 2. Chassis 2d discharge opening 3 Lever bearing of housing 4 Shaft 5 Surface contact of the housing for the piezoelectric actuator 6 Housing Sleeve 7 First housing sleeve part 8 Second housing sleeve part 8f. Guide sleeve in the second housing sleeve part for guiding the closing spring 9 Threads 10 Piezo Actuator 11 Piezo actuator front part 12 Encapsulation 13 Ring Seal 14 Support surface 15 Fluid Unit 16 Valves / Nozzles 17 Fluid Positioning Unit 18 Fluid unit connection nut 19 Connecting nut ring seal 20 Transmission lever / lever 21 Short lever arm 22 Bearings for shafts 23 Long lever arm 24 Actuator engagement point close to tilt axis / roller bearing 24z Cylinder pin close to actuator engagement point 25 Plunger contact point away from tilt axis 26 Spherical Cap 27 Transmission lever pretensioning spring contact point / plate-shaped part 28 Transmission lever hole / through opening for rod part 40 Plunger device 41 First rod element / transmission element 42 Transmission element rod part 43 Annular groove in rod 45 Transmission element head sleeve part 46 Circular spring in head sleeve section 47 Head sleeve flange 47a First flange surface, valve side 47b Second flange surface 48 Bearing block 49 Spherical Shell 51 Second rod element / closure element / plunger 52 Plunger tip of plunger / closing element of plunger device 53 Plunger Head 60 Spring Arrangement 61 Open spring arrangement / open spring / compression coil spring 63 Guide sleeve for closure element 64a, b Closing spring arrangement / closing spring / compression spring 66a Housing Restrictions / Edges 66b Housing part 67 Pretensioning spring / Compression coil spring 70 Connecting spring 80 Shield 81 First permanent magnet 82 Hall Sensors / Hall Probes 83 Second permanent magnet 84 Gap DR Metering direction / direction from transmission lever to valve E10 Extension direction of the piezo actuator E 20 Transmission lever extension direction / Lever arm length direction E 40 Extension direction of plunger device S Q Second axis of symmetry of the actuator's plane of symmetry Tilt axis through R shaft

Claims

1. A metering system (1), wherein the metering system (1) comprises a housing (2), a piezo actuator (10) located therein, a fluid unit (15) having a valve (16), a plunger device (40) for closing the valve (16), and a transmission lever (20) for connecting the piezo actuator (10) to the plunger device (40), and the piezo actuator (10) is arranged substantially parallel and adjacent to the plunger device (40) within the housing (2), the piezo actuator (10) extends away from the transmission lever (20) in a direction substantially towards the valve (16), the piezo actuator (10) is tensioned relative to the housing (2) by a spring arrangement (60) via the plunger device (40) and the transmission lever (20), the spring arrangement (60) having a plurality of springs (61, 64a, 64b, 67) for spring tensioning of the plunger device (40), a metering system (1).

2. The transmission lever (20) extends in a lateral direction with respect to the extending direction (E 10 of the piezoelectric actuator (10) and the extending direction (E 40 of the plunger device (40). as described in the metering system according to claim 1.

3. The plunger device (40) is formed from at least two rod elements (41, 51) which are tensioned relative to each other, the metering system according to claim 1.

4. The plunger device (40) comprises a transmission element (41) as a first rod element (41) on the lever side and a closing element (51) as a second rod element (51) on the valve side, the metering system according to claim 3.

5. The spring arrangement (60) has a plurality of compression coil springs (61, 64a, 64b, 67) for spring tensioning of the plunger device (40) and / or an opening spring arrangement (61) for opening the valve (16), and a closing spring arrangement (64a, 64b) for closing the valve (16) having a higher spring constant and / or pre-tensioning force than the opening spring arrangement (61), the metering system according to claim 1. Claim 6. The closing spring arrangement (64a, 64b) has at least two closing springs (64a, 64b) operating in the same direction and operating in a direction opposite to that of the opening spring arrangement (61).

7. The opening spring arrangement (61) elastically engages with the closing element (51) in the housing (2) such that a force acts on the closing element (51) to move the closing element (51) in the direction of the open valve position. The closing spring arrangement (64a, 64b) elastically tensions the transmission element (41) in the housing (2) such that a reaction force acts on the transmission element (41) to move the transmission element (41) against the closing element (51), and thus to move the closing element (51) in the direction of the closed valve position. The meter ring system according to claim 5.

8. The transmission element (41) has two parts (42, 45) that can be connected to each other. The meter ring system according to claim 4.

9. The two parts (42, 45) of the transmission element (41) that can be connected to each other are a rod part (42) and a head sleeve part (45). And / or The head sleeve part (45) has a flange (47) where the transmission lever (20) is located on the valve side. The meter ring system according to claim 8.

10. The elongated rod part (42) of the transmission element (41) is located on the valve side of the closing element (51) and extends from there to the head sleeve part (45) on the other side of the transmission lever (20). The meter ring system according to claim 9.

11. The elongated rod part (42) extends from the closing element (51), through a through opening (28) in the transmission lever (20), to the head sleeve part (45) on the other side of the transmission lever (20). The meter ring system according to claim 10.

12. The rod portion (42) of the transmission element (41) is axially guided with a relatively narrow play around the radial direction, parallel to the piezo actuator (10), inside the first housing sleeve portion (7) of the housing sleeve (6) of the housing (2) on the valve side. The head sleeve portion (45) of the transmission element (41) facing away from the valve has a relatively wide play around the radial direction and is guided. The meter ring system according to claim 9.

13. One of the closing springs (64b) of the spring arrangement (60) is located on the head sleeve portion (45) on the flange surface (47b) of the flange (47) facing away from the valve. The meter ring system according to claim 9.

14. The flange (47) of the head sleeve portion (45) has a spherical shell (49) protruding hemispherically on the valve side, and the spherical shell (49) forms a bearing (26, 49) together with a corresponding spherical cap (26), and the spherical cap (26) is formed on the transmission lever (20) for this purpose. The meter ring system according to claim 9.

15. The first permanent magnet (81) is fastened to the plunger device (40). A hall sensor (82) is positioned opposite this permanent magnet (81) within the housing (2), separated by a gap (84). The meter ring system according to claim 1.

16. The first permanent magnet (81) is fastened to the head sleeve portion (45) of the transmission element (41). The meter ring system according to claim 15.

17. A second permanent magnet (83) is arranged on the side of the hall sensor (82) facing away from the first permanent magnet (81), and the second permanent magnet (83) has a magnetic field opposite to that of the first permanent magnet (81), and / or The surrounding area around the hall sensor (82) is magnetically protected by a shield (80) at least on the side facing away from the first permanent magnet (81). The meter ring system according to claim 15.

18. To adjust the distance between the valve (16) and the closing element (51), the housing sleeve (6) is attached to the surrounding housing (2) of the meter ring system (1) so that its position can be adjusted. The meter ring system according to claim 12.

19. The transmission lever (20) is tiltably fitted to an inclined axis (R) in the form of a shaft (4) on the side facing the piezo actuator (10), and the shaft (4) is respectively fastened to the end sides of the lever bearings (3). The piezo actuator (10) for opening the valve (16) is in the form of a roller bearing and is located close to the inclined axis at a right angle to the inclined axis (R) in the transmission lever (20) at the actuator engagement point (24). The meter ring system according to claim 1.

20. The transmission lever (20) is configured and arranged such that the actuator engagement point (24) of the piezo actuator (10) in the transmission lever (20) is on a line between the roller bearing surface of the shaft (4) of the inclined axis (R) with respect to the transmission lever (20) and the spherical shell (49) in the flange (47) of the head sleeve portion (45) in the spherical cap (26) in the transmission lever (20), and tension is applied to the plunger device (40) through the transmission lever (20) with respect to the piezo actuator (10) at the non-energized starting position of the piezo actuator (10). The meter ring system according to claim 19.

21. The closing element (51) is removably installed in the meter ring system (1). The meter ring system according to claim 4.

22. The closing element (51) is removably installed in the meter ring system (1) together with the fluid unit (15). The meter ring system according to claim 21.

Images