DOSING SYSTEM

Description

[0001] The invention relates to a dosing system for dosing a dosing medium, comprising a frame housing unit, a lever bearing unit mounted on the frame housing unit with a lever support, a lever mounted rotatably about a tilt axis by means of the lever support and having a two-sided lever arm extending substantially in a longitudinal direction, wherein one lever arm side has a first actuator engagement point close to the tilt axis and is in contact with an ejection element at an end section remote from the tilt axis, and wherein the other lever arm side has a second actuator engagement point close to the tilt axis. The dosing system further comprises two actuators which, during operation, exert a counter-rotating tilting moment on the lever at the first and second actuator engagement points.

[0002] Dosing systems of the type mentioned above are typically used to precisely dispense a medium, typically a liquid to viscous dosing substance. Within the scope of so-called "micro-dosing technology," it is often necessary for very small amounts of the dosing medium or dosing substance to be applied to a target surface with pinpoint accuracy, without contact, i.e., without direct contact between the dispensing system and a target surface. Such a contactless process is often referred to as a "jet process." A typical example is the dispensing of dots of adhesive, solder paste, etc., when assembling printed circuit boards or other electronic components, or the application of converter materials for LEDs.

[0003] A key requirement is to deliver the dispensing media to the target surface with high precision, i.e., at the right time, to the right place, and in a precisely metered amount. This can be achieved, for example, by dispensing the dispensing medium dropwise via a nozzle of the dispensing system. A preferred method is the ejection of individual droplets in a type of "inkjet process," similar to that used in inkjet printers, among others. The size of the droplets and the amount of medium per droplet can be predicted as precisely as possible through the design and control of the nozzle, as well as the resulting effect.

[0004] To dispense the medium from the dosing system, a movable ejection element (usually a plunger) can be arranged in the nozzle of the dosing system. The plunger can be pushed or moved forward at a relatively high speed inside the nozzle toward a nozzle opening, i.e., in a dosing direction, thereby ejecting a drop of medium, and then retracted again.

[0005] Typically, the plunger can also be moved into a closed position by firmly connecting it to a sealing seat in the nozzle opening and temporarily remaining there. For more viscous dosing media, it may also be sufficient for the plunger to simply remain in the retracted position, i.e., away from the sealing seat, without a single drop of the medium escaping from the nozzle opening.

[0006] The present invention can be used in all of the aforementioned variants regardless of the specific ejection principle, ie in a jet process, an open ink-jet process or even with a classic closure element.

[0007] Due to the desire to continually achieve higher machine productivity and working speed, a further requirement is now to apply the dosing media ever faster, for example the droplets with a high ejection frequency, i.e. in rapid temporal succession, to the target surface.

[0008] This creates vibrations that can spread from the dynamically excited components in the dosing system to the entire dosing system. Since the dosing system is a system capable of vibration, the excitations in the system's structure may be amplified. In particular, a natural frequency of the system may be excited. If the natural frequency and the excitation frequency coincide, resonant vibrations are generated, causing undesirable relative movements that can negatively impact the dosing behavior, particularly the dosing accuracy and quality.

[0009] Dosing systems known in practice can only theoretically achieve such desired discharge frequencies. Tests have shown that currently available dosing systems can no longer operate stably and smoothly within the required quality criteria at the desired discharge frequencies. Both dosing quality and dosing accuracy deteriorate to such an extent that it is impossible to achieve a satisfactory dosing result at the intended dosing frequencies.

[0010] To address this problem, preload springs, i.e. springs for directly preloading the actuators, are often used in practice. A design with actuators preloaded with such preload springs is known, for example, from KR 101 301 107 B1. Under high dynamic loads, the components, in particular the actuators and frame components, heat up unevenly and to varying degrees. This results in a different position of the closure element in relation to the nozzle and thus a deviation in the dispensing result. In addition, at high excitation frequencies, natural resonances of the dynamically resonating preload springs can occur, which then also negatively influence the dispensing process. In the desired high frequency ranges, this can therefore lead to interference and / or resonance effects, for example, which have a negative impact on the dispensing result in the short term and increased friction or wear in the long term.lead to increased wear of the components concerned.

[0011] It is therefore an object of the present invention to improve known dosing systems, in particular to provide a particularly fast dosing system with which a higher dosing frequency is achieved with high dosing accuracy and dosing quality of dosing media on a workpiece.

[0012] This object is achieved by a dosing system according to patent claim 1.

[0013] The dosing system according to the invention for dosing a dosing medium onto a workpiece or substrate comprises, as mentioned above, a frame housing unit. A frame housing unit refers to a "frame-like" housing of the dosing system, i.e., a housing that encloses most of the components of the dosing system, such as a movement mechanism of the dosing system, which will be explained later. For functional reasons, the frame housing unit is designed to be relatively solid and inert, as it acts as a stable abutment or inert support for the dosing system, in particular to provide resilient support for the dynamic components of the dosing system, such as the aforementioned movement mechanism, relative to it, as explained further below.

[0014] The frame housing unit is designed in such a way, i.e., sufficiently inert and massive, that it responds little to nothing to the high vibration or movement frequencies of the movement mechanism, thus acting statically relative to the dynamic movement mechanism. By thus stabilizing the entire dosing system, it ensures consistently good dosing performance.

[0015] It can preferably form a first main mass of the dosing system with a low natural frequency, which is as insensitive as possible to a frequency range of the dynamic, high-frequency moving, lighter individual components of the movement mechanics of the dosing system, ie is not excited to oscillate as far as possible, so that interference-induced oscillation or post-oscillation of the entire dosing system during dosing operation due to the different oscillation frequencies is almost impossible.

[0016] As already mentioned at the beginning, the dosing system according to the invention further comprises a lever bearing unit mounted on the frame housing unit with at least one lever support for a lever of the dosing system. The lever bearing unit is advantageously separated from the frame housing unit in that it is structurally protected against tilting or twisting, but can be displaced along an axis in a depth direction or dosing direction relative to the frame. This displacement is prevented by the piezoelectric actuators, which are spring-loaded between the frame housing unit and the lever bearing unit via the lever bearing unit. This ensures that a thermally identical change in the two piezoelectric actuators and / or a thermal change in the frame housing unit leads to a relevant change in the distance between the nozzle and the ejection element, as will be explained later.

[0017] The lever bearing unit is preferably arranged partly inside and partly outside the frame housing unit, i.e. mounted on the frame housing unit.

[0018] The lever support of the lever bearing unit is a first pivot bearing part of a pivot bearing, which is part of the movement mechanism. The pivot bearing or tilting bearing is formed from the lever support and the lever and indirectly transmits the force, which is alternately generated by the two actuators for dosing operation, to the driven ejection element. The ejection element, which can also preferably be a plunger in the present design of the invention, then conveys a dosing medium at least in portions from the nozzle according to one of the dosing methods or dosing types explained above.

[0019] Literally, the lever support serves as a support for the lever, which is mounted rotatably or tiltably about a tilting axis of the tilting bearing by means of the lever support. This allows the lever to be moved relative to the tilting axis in a designated dosing direction of the dosing system from an initial rest position, namely a horizontal center position, or at least tilted by a certain angle that defines the stroke length. The tilting axis or rotation axis, on which the lever is tiltably mounted, also runs horizontally, but perpendicular to the lever or to a longitudinal direction of the lever.

[0020] Relative directions such as "top", "bottom", "upper", "under", "lateral", "left", "right", "longitudinal" etc. refer arbitrarily to the representation in the figures described below, although the dosing system is mainly operated in the direction shown in Figure 1This means that dosing onto a workpiece in the jet process usually occurs in such a way that the dosed drops essentially fall or fly towards the workpiece due to gravity, i.e. dosing occurs in the dosing direction or in a downward depth direction.

[0021] In the broadest sense, the lever simply refers to a mechanical force converter consisting of a rigid body that, as usual, is mounted for rotation about a pivot point, namely the tilting axis. The lever of the dosing system according to the invention comprises a two-sided or two-armed lever arm extending essentially in a longitudinal direction. "Essentially in a longitudinal direction" means that the lever extends through the dosing system in at least one main direction of extension, namely a longitudinal deflection direction between the ejection element and the actuators. However, the lever is fundamentally a three-dimensional component that also extends at least partially in the other two orthogonal spatial directions.For example, it can extend in a transverse direction (parallel to the tilt axis) between two side surfaces or in a depth direction (perpendicular to the tilt axis and the longitudinal axis), in the direction of the lever support at least to the extent that it measures at least a fraction of its main direction of extension in the longitudinal direction in these directions.

[0022] As is generally the case, the term "lever arm" refers to the part (or length) of a lever that extends from a tilting axis or a rotational axis of the lever to a point of application where the force acts on the lever. A two-sided or two-armed lever arm accordingly has two such parts or lever arms, each with a point of application where a force acts on the lever. The lever arms can also be referred to below as the lever arm sides of the lever arm. The respective distances of the points of application from the common rotational axis are also referred to as the lever arm lengths. In principle, the greater the distance of a point of application from the tilting axis, i.e., the greater the lever arm length, the smaller the force can be to compensate for a correspondingly greater force with a correspondingly shorter lever arm length.

[0023] In the dosing system according to the invention, one of the lever arm sides of the two-sided lever arm has a first actuator engagement point near the tilt axis, i.e., a first point at which the force is applied. At an end section away from the tilt axis, the respective lever arm side is in contact with the aforementioned ejection element and a nozzle of the dosing system. The movement of the lever in the dosing direction of the dosing system is, in turn, transmitted to the ejection element as intended. The terms "near the tilt axis" and "far from the tilt axis" are to be understood relative to one another. An arrangement near the tilt axis therefore simply means that the component in question is arranged closer to the tilt axis than a component arranged far from the tilt axis.

[0024] The other lever arm side also has a second actuator engagement point close to the tilt axis—that is, a second point where the force acts alternately with the first point, as explained below. On the lever arm side far from the tilt axis with the second actuator engagement point (away from the ejection element), the respective lever arm side can be designed symmetrically to the other lever arm side, e.g., simply to run into empty space. Preferred designs and further developments of the lever will be explained later.

[0025] Furthermore, the dosing system according to the invention comprises two actuators which, during operation, exert a tilting moment on the lever at the first and second actuator engagement points in opposite directions.

[0026] In the context of the invention, a tilting moment is simply understood to mean a torque that ensures that the lever tilts by a certain angle and thus moves the ejection element in contact with it as intended for dosing. However, the term "tilting moment" used here does not refer to a classic tilting moment, where a body subjected to it tilts or tips over from this specific tilting moment onwards. Rather, tilting literally refers to the tilting of the lever by a certain angle to the horizontal or to a central position in which the lever is located, at least initially before commissioning or at a time when the actuators are de-energized.

[0027] The above actuator engagement points refer to at least individual points or actuator contact points in the sense of contact or engagement points of the actuators on the lever, at which the actuators engage the lever or are in contact with the lever. Actuator engagement points can, however, also consist of a plurality of points, a line, or a surface. For example, the actuator engagement points can be designed as two elongated engagement lines or actuator contact points running transversely to the lever and perpendicular to the directions of action of the actuators. This is useful for limiting the rotational movement or tilting movement of the lever relative to the lever support to only the intended tilting movement around the tilting axis for moving the ejection element in a desired dosing direction. This means that almost no further rotational components can arise that could, for example, cause additional friction or wear in the system.Preferred designs of the actuators will also be explained later.

[0028] According to the invention, the actuators of the dosing system mentioned above are arranged at an angle to one another in a V-shape. "Arranged at an angle to one another" means that the actuators converge at an angle to one another at the front in a common plane or are directed at an angle to a common point beyond or behind the tilting axis. In an embodiment explained further below, for example, they are directed at a point below the horizontal plane of the tilting axis of the tilting bearing consisting of the lever support and the lever.

[0029] In any case, "positioned at an angle to one another" primarily means that the actuators or their directions of action are positioned or aligned at an angle of less than 180° but greater than 0° to one another. The invention thus avoids the idea of the actuators being aligned exactly opposite one another, or parallel or antiparallel to one another, as will be explained in more detail below.

[0030] Furthermore, the lever bearing unit (with the lever support), the lever, and the two actuators together form a movement mechanism. According to the invention, this movement mechanism is clamped to the frame housing unit by means of at least one spring element.

[0031] The movement mechanism is designed in such a way that it can set the ejection element of the dosing system into a longitudinal ejection and retraction movement in and against the dosing direction, i.e., in a normally conventional arrangement, downwards or upwards, as required, at particularly high frequencies. For this purpose, the ejection element can be structurally connected or coupled to the movement mechanism at an actuation point, e.g. the plunger on a plunger head, or can be preloaded against it by means of a spring, such as a torsion spring, i.e., for example, only in pressure contact. In any case, the coupling is achieved in such a way that the tilting moment generated by the actuators - typically a simple linear deflection or linear movement - is alternately or alternately transmitted from the lever (as an ejection or retraction movement) via a contact surface of the lever to the ejection element, preferably a plunger head of the plunger, to dispense the dosing medium from the nozzle.

[0032] The spring element can, for example, be at least one compression spring. It can be preloaded with approximately 3-4 kN, i.e., resiliently clamp the movement mechanism against the frame housing unit. The two actuators can be preloaded or prestressed with 1.5 to 2 kN each, for example, preferably 1.8 kN. Preferred configurations of the spring element will be explained later.

[0033] The inventive design of the subject matter of the invention allows the dosing system to operate at a higher discharge frequency while maintaining consistently good dosing accuracy and quality. Furthermore, the inventive design eliminates the need for a dynamically loaded return spring on each of the two actuators. Such return springs do not operate stably at all frequencies, as they can lead to wobbling movements or unwanted vibrations in the system, particularly during rapid or high-frequency dosing, as desired in the invention.

[0034] The overall spring-loaded preload of the movement mechanism against the frame housing unit ensures that dynamic vibrations remain within the dynamic system, although the overall spring-loaded preload is not part of the dynamic system. Furthermore, any individual thermal effects caused by different local heating of the individual dosing system components (piezo actuators, frame housing unit, levers, etc.) do not individually affect the distance between the ejection element and the nozzle, as was previously the case in the state of the art, but are largely compensated for. The dosing accuracy and quality of the entire dosing system can therefore no longer be significantly influenced by such effects.

[0035] The inventive design of the subject matter of the invention, in particular the inclined position of the actuators in a common plane, also enables a closer or closer position of the actuators' points of action on both sides around the pivot point of the lever, which in turn moves the ejection element for dosing via its lever arm. Because the lever can be made smaller and lighter and consequently has a lower moment of inertia, higher accelerations and thus faster dosing can be achieved with the dosing system according to the invention.

[0036] As a further advantage, the size of the droplets or the amount of medium per droplet can be further reduced. Furthermore, larger areas can be wetted with a dosing medium in the same time interval. The design according to the invention is particularly suitable for contactless dosing of small quantities of a dosing medium or dosing substance—i.e., microdosed, very precisely, and contactless, i.e., without direct contact between the dosing system and a target surface—onto a target surface, namely in the jet process or dosing by means of the jet process.

[0037] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description, wherein individual features of different embodiments or variants can also be combined to form new embodiments or variants.

[0038] There are various options for increasing the dispensing system's discharge frequency. For example, the movement mechanism, especially the lever, can be optimized or improved.

[0039] In principle, the actuators, positioned at an angle to each other, could engage on both long sides of the lever, for example, at an end section of a lever arm. For this purpose, an actuator engagement point could be provided on each of the two opposite long sides of the lever.

[0040] Preferably, the two actuators can be located on a common longitudinal side of the lever so that they can act on the lever essentially from a common direction. Accordingly, the first actuator actuation point and the second actuator actuation point can be designed and arranged on the same longitudinal side of the lever. In a normal arrangement of the dosing system (with the dosing opening facing downwards), said longitudinal side - for example in the embodiment described in more detail later - is a longitudinally extending upper side of the lever. Thus, they only exert a counter-directional or alternating tilting moment on one longitudinal side of the lever, thus only loading the lever on one side. In addition, sufficient space is available on the opposite (usually lower) longitudinal side of the lever for the lever support, which ensures a particularly space-saving, compact design of the dosing system as a whole.In addition, the arrangement of the actuators on one long side of the lever allows the lever support and the lever to be simultaneously tensioned against the actuators by means of the spring element mentioned above, so that the movement mechanism as a "dynamic" unit is pre-tensioned against the frame housing unit as a "static" unit in a vibration-calming manner.

[0041] There are preferred options for the position of the actuators relative to the lever. For example, one actuator could engage the lever vertically, while the other actuator could be positioned at an angle to the lever, so that the two actuators are always positioned at an angle to each other.

[0042] The actuators are each arranged at the same angle to a common angle bisector or axis of symmetry (an imaginary "V" of the actuators), with the angle bisector or axis of symmetry being perpendicular to the top of the lever. Viewed from a long side, the actuators can thus be arranged in a V-shape such that they could be aligned by means of an imaginary reflection at the axis of symmetry or angle bisector. Viewed spatially, the actuators can be arranged in a V-shape such that they could be aligned by means of an imaginary reflection at a plane of symmetry formed by said axis of symmetry and a symmetry axis running horizontally between the actuators perpendicular to it, as will be explained later using an exemplary embodiment.

[0043] Particularly preferably, the actuators can be arranged in a V-shape, inclined relative to one another, such that the longitudinal direction of the lever or the lever's longitudinal axis lies in a virtual plane spanned by the direction of action or the longitudinal axis of the actuators, or the tilting axis of the lever is perpendicular to this virtual plane. Practically speaking, this allows the dosing system to be designed to be extremely flat despite the actuators being inclined relative to one another (in a transverse direction perpendicular to the longitudinal direction of the lever), namely similarly flat as designs in which only one actuator or two parallel actuators are installed, as was previously the case.

[0044] In principle, the actuators can be arranged in the angular range between two extreme positions - namely a parallel, side-by-side position on the one hand and an opposite frontal position, ie when the actuators run in a line or common alignment from different sides towards the lever and each other - (excluding the said extreme positions) obliquely to each other on a long side of the lever, axially symmetrical to the common angle bisector.

[0045] According to a preferred embodiment of the invention, the actuators, or more precisely their longitudinal axes or directions of action, can be positioned or arranged in a V-shape at a maximum or at most 150° to one another. More preferably, they can be aligned at a maximum of 120° and even more preferably at a maximum of 90° to one another. Particularly preferably, they can be inclined at a maximum of 60° and most preferably at a maximum of 30° to one another.

[0046] Angles smaller than 20°, especially smaller than 10°, can then only be achieved by using a correspondingly smaller cross-section for the actuators or by extending and thinning the actuator transformers accordingly. For an angle of 20°, "correspondingly smaller" would mean, for example, that half the cross-section of each actuator must be less than 10° in any case. The aforementioned extension, however, would inevitably lead to a significant increase in the size of the housing or dosing system, which in turn would make the structure larger and more susceptible to bending strength.

[0047] Nevertheless, if the disadvantages mentioned are not relevant, it could also be desirable for the actuators to be inclined to each other, preferably at a maximum angle of 20° and particularly preferably at a maximum angle of 10°.

[0048] As is generally known, the more steeply the actuators are positioned relative to one another, i.e. the smaller the common angle between them, the more force is transferred to the lever, as they are, so to speak, more "perpendicular" to the lever, and the proportion of transverse forces decreases. At the same time, however, a steeper arrangement also means that the actuators at the tip have to be moved further and further apart, or spaced from one another, as their dimensions mean they get in the way or block each other, particularly due to their transverse extent or their diameter perpendicular to their longitudinal axis. Consequently, the actuator application points move further and further apart, or closer together, as the position becomes steeper.from the intermediate tilt axis until, in a parallel position, they are spaced from each other at least by their diameter relative to their central longitudinal axes, as is disadvantageously the case in the prior art. The force arm of an actuator in a parallel arrangement of two actuators corresponds to half the diameter of one actuator.

[0049] Since the achievable mechanical energy of piezoelectric actuators depends on the actuator volume—that is, the cross-section or diameter, as well as the length of the actuator—thinner actuators possess less force than thicker actuators of the same length. Furthermore, the thinner the actuators, the more unstable and unpredictable their behavior (see "buckling rod problem" or "flexural strength"). For the reasons mentioned above, it is therefore of no use to use thinner, correspondingly longer actuators to reduce the force arm, which in turn increases the lever deflection.

[0050] The farther away or removed from the tilt axis the actuators engage the lever, the less stroke or lever deflection can be translated or transferred to the lever with their length-dependent, fixed stroke length of the respective actuator. This is because the stroke length of an actuator – in a design with stacked piezo elements, i.e., a "piezo stack actuator" – depends on its specific length (and is therefore limited for a given length). Therefore, by optimally selecting the position, i.e., the actuator engagement point at which the respective actuator engages the lever, the possible lever deflection can be advantageously increased using the lever, despite the limited stroke length of the actuator itself, in order to achieve a greater stroke movement than the actual stroke length of the actuator. The closer the actuator is engaged to the tilt axis, the greater the lever deflection, but also the more force is required due to the shorter force arm.

[0051] With an inclined position, compared to a parallel arrangement of two actuators - with the same design of the actuators - the actuators can be arranged closer to the tilt axis, so that a larger lever deflection can be achieved.

[0052] The actuators of the dosing system can be implemented in various ways, with piezo actuators being preferred, especially for applications requiring extremely fine dosing resolution. Piezo actuators, also known as piezoelectrically operated actuators, have the advantage of very precise and, above all, fast controllability compared to other types of actuators, such as hydraulically, pneumatically, and / or electromagnetically operated actuators. Piezo actuators are advantageously characterized by extremely short reaction or response times, which are usually significantly shorter than the corresponding values of other actuator principles. A further advantage is that piezo actuators require comparatively little installation space within a dosing system compared to other types of actuators. Thus, piezo actuators offer an efficient solution for the operation of dosing systems, especially for extremely fine dosing requirements.

[0053] Piezoelectric stack actuators generally have a relatively short stroke but can generate relatively high forces. For example, a 36 mm long piezo stack can achieve a stroke length of 50 µm. Therefore, it is generally necessary to translate the short stroke so that it becomes significantly larger, which of course results in a corresponding reduction in force.

[0054] Alternatively, the actuators can also be magnetostrictive actuators. These utilize the principle that the dipoles of a ferromagnetic material align themselves in the same direction, i.e., in a common orientation, when an external magnetic field is applied. By rotating the dipoles relative to their original position, the length of the material changes, depending on the material, approximately in the range of several µm / m to mm / m.

[0055] The dispensing system can therefore preferably be designed so that the actuators act as close to the tilting axis as possible in order to achieve the greatest possible lever deflection. Since the force of the actuators consequently decreases and the force arm only contributes to the first power of the driving torque – which results in a disadvantage in dynamic applications, e.g., when the dispensing system in a dispensing system is dynamically moved relative to the workpiece for dispensing – it is advantageous to keep the dimensions of the lever or general lever dimensions as small as possible in order to achieve a faster dispensing system. Due to the conservation of angular momentum, a lever with a lower moment of inertia can be "rotated" or moved back and forth around the rotational or tilting axis more quickly than a lever with a higher moment of inertia.

[0056] Since the moment of inertia depends to the second power on the distance of the respective mass point (of the lever) to the pivot point or to the tilting axis, it increases disproportionately with the length of the lever (and thus the distances of the mass points from the pivot point).

[0057] The moment of inertia of the lever can also be reduced for a given transmission ratio (force to force arm) by arranging the actuators at an angle to each other, as this reduces the distance of the force arms from the pivot point or the length of the force arms, which in turn allows for the design of a smaller lever. A smaller lever, and consequently a smaller moment of inertia, ultimately leads to a higher resonance frequency of the dosing system with actuators positioned at an angle to each other than in a system with parallel actuators of the same design.

[0058] Therefore, for faster movement of the lever, it is advantageous to center more mass closer to the tilt axis.

[0059] Preferably, the lever can therefore have an inhomogeneous mass distribution. Inhomogeneous means that the mass of the lever is not distributed symmetrically or evenly along its length in the longitudinal direction, but rather the lever is constructed asymmetrically, at least with respect to its mass.

[0060] Particularly preferably, a mass of the lever can also be distributed along the lever relative to the tilting axis in such a way that the lever as a whole has the lowest possible (mass) moment of inertia relative to the tilting axis. Therefore, the design preferably also ensures that as much mass as possible is located near the pivot point and as little mass as possible away from the pivot point, i.e., in the elongated boom toward the ejection element.

[0061] In this case, the weight of the lever can preferably be reduced or distributed toward the pivot point only just enough to ensure sufficient stability, which, among other things, allows for particularly rapid swinging of the lever. For example, the lever, viewed from above, can be essentially "bucket-shaped" in outline, with a predominant portion of the mass near the pivot point being positioned in an "oval" or "round" section around the pivot point.

[0062] Preferably, the lever can have a plurality of recesses, particularly preferably through-holes running transversely or in the transverse direction of the lever, to reduce weight.

[0063] Preferably, the actuator engagement points on the lever for the actuators cannot be located or arranged in a horizontal plane of the tilt axis. This means that they are not located in the same plane as the tilt axis, in which the tilt axis itself lies.

[0064] Especially in a dynamic case (e.g. when the dosing system in a dosing system is moved dynamically for dosing relative to the workpiece), when the lever is tilted by a few degrees around the tilt axis due to the tilting moments of the actuators, the off-plan arrangement of the actuator engagement points on the lever advantageously ensures that the actuators only execute the smallest possible transverse or shear movements perpendicular to the direction of action of the actuators when exerting the tilting moment (in the form of a longitudinal deflection) on the lever.

[0065] With larger transverse movements, i.e., directional components transverse to the direction of action or transverse components, an otherwise rectilinear deflection in the direction of action results in a distinctly arcuate pendulum motion of the actuators along a rotational circle or circle around the tilting axis through the two actuator engagement points of the actuators on the lever. By reducing the transverse components, the pendulum motion becomes more rectilinear. This minimizes the possibility of the actuators, which have a very high mass, oscillating transversely during their longitudinal deflection in the direction of action, thus causing undesirable vibration effects and / or increased wear on the components.

[0066] In principle, the actuator engagement points can be formed above the tilt axis of the lever, for example directly on the surface of the top of the lever, so that the actuators engage the lever there.

[0067] In order to be able to arrange the actuator engagement points even closer to the tilting axis when the actuators are arranged at an angle to one another, the lever can preferably be designed and arranged such that the two actuator engagement points are positioned or recessed in the lever further away from a top side or long side of the lever facing the actuators than the tilting axis, on which tilting axis the lever rests, as mentioned, on the lever support, mounted rotatably or tiltably. "Further away from a top side or long side of the lever facing the actuators" means that, when the lever is arranged as intended on the lever support, the actuator engagement points are arranged further away from the piezo elements of the actuators or deeper in the lever than the tilting axis. The actuators are therefore arranged such that their front or tip initially pass the tilting axis, i.e., they pass or overlap the horizontal plane of the tilting axis.and then only engage the lever at the recessed actuator engagement points below the actual tilting axis or only come into contact with the lever there.

[0068] The respective actuator engagement points of the two actuators can thus be arranged parallel to the common tilt axis in the same way or with identical offsets. In an alternative preferred embodiment, the actuators could also each act on an actuator engagement point of the lever that is offset in the transverse direction or parallel to the longitudinal direction.

[0069] Preferably, the actuators arranged or striking in a V-shape on the lever can be aligned or engage the actuator engagement points in such a way that, in a horizontal middle position of the lever, a longitudinal axis of the actuators is substantially perpendicular to a respective connecting line between the respective actuator engagement point and the common tilting axis.

[0070] In other words, the actuators act at the actuator engagement points offset by the connecting line, at right angles to the tilt axis. The center position of the lever corresponds to a position or position of the lever in which the lever is horizontal and both actuators are de-energized or de-energized.

[0071] The actuators can therefore act in a V-shape at the actuator engagement points of the lever, each in a direction of action running past the tilting axis, in which they are arranged or inclined in such a way that their direction of action is tangential to the circle around the central tilting axis of the lever through the two actuator engagement points of the actuators on the lever (or perpendicular to the connecting line from the respective actuator engagement point to the tilting axis, in particular to the surface of the cylindrical pins forming the tilting axis, as will be explained later in an exemplary embodiment), in order to keep transverse movements or a transverse component of the pendulum movements of the actuators along the circle or an arc length of the circle - along which the actuator engagement points are moved or displaced - as small as possible when the actuators move back and forth, i.e. the piezo elements expand or contract.

[0072] At this point, it should be noted that, viewed microscopically, it is not the central axes of the cylindrical pins that exactly represent the tilting axis, but rather the connection between the cylindrical pin surfaces (which are firmly seated in the lever support on the underside) and the slightly larger, cylindrically recessed surfaces of the lever, which are pressed tangentially against each other so that the lever surfaces execute a minimal rolling motion on the cylindrical pin surfaces when tilted. In this sense, therefore, there is no exact tilting axis, but rather a more complex movement. However, at least from a macroscopic perspective, the central axes of the cylindrical pins can be roughly equated with the tilting axis.

[0073] In other words, the actuators can preferably be arranged tangentially to a circle around the tilt axis at the actuator engagement points such that, during operation for dosing a dosing medium, they essentially perform a rectilinear movement during an ejection and retraction movement. "Essentially" here means that, during an ejection and retraction movement, the actuators perform a rectilinear movement without any significant transverse movement on the circle, in the sense of a pendulum motion. The aforementioned tangential arrangement means that the longitudinal axes or directions of action of the actuators are tangential to the circle around the tilt axis at the actuator engagement points, as already explained above.

[0074] There are preferred options for the further design of the dosing system.

[0075] Preferably, the lever bearing unit can be designed in several parts.

[0076] Particularly preferably, in addition to the lever support already explained, it can comprise a fluidic positioning device for a fluidic unit of the dosing system. This fluidic unit of the dosing system can also be coupled to the lever bearing unit.

[0077] In this case, the lever support can particularly preferably be connected to the fluidic positioning in a rotatable, articulated or tiltable manner via a rotary joint located outside the frame housing unit.

[0078] Alternatively or additionally, the lever support and the fluidic positioning can be mounted mechanically adjustable relative to each other, i.e. in the sense of being rotatable, tiltable or displaceable, for example by means of an adjusting element adjustable in angle relative to the swivel joint.

[0079] The lever bearing unit can preferably comprise a ring structure which encloses a section of the frame housing unit in a ring-like manner, leaving at least one gap. A "gap" is understood here, as usual, to be a narrow, elongated opening forming an intermediate space. "Ring structure" or "ring-like" refers to a structure consisting of two components that are shaped or constructed, i.e., structurally designed, in the manner of a ring. The ring structure thus refers to an annular structure or an annular arrangement in which the two components can be circularly connected to form a self-contained ring. The section of the frame housing unit can, for example, be a housing base of the frame housing unit.

[0080] Particularly preferably, the lever bearing unit can be displaceably mounted on the frame housing unit by means of the spring element, which is preferably arranged in a gap between the lever bearing unit and the section of the frame housing unit.

[0081] Alternatively or additionally, the ring structure may include a swivel joint. If the dosing system is constructed as described above, the swivel joint may be the one described above.

[0082] The lever support of the lever bearing unit can be mechanically adjustable and coupled to the fluidic positioning system via the lever and the tappet for adjusting the tappet-nozzle distance on a side of the fluidic positioning system remote from the pivot joint by means of an adjusting element, in particular an adjusting screw, while leaving at least one gap to the frame housing unit, enclosing the spring element in a ring-like manner in the ring structure of the lever bearing unit against itself. The adjusting screw can also be a fine-thread screw, for example, with which the position of the tappet in the nozzle, i.e. the tappet-nozzle distance, can be finely adjusted or set even more precisely.

[0083] The "side remote from the pivot joint" here means at least a section along the fluidic positioning (from the pivot joint to the tappet) which is located on a tappet-side half beyond the center of the fluidic positioning, i.e. as close as possible to the tappet.

[0084] Notwithstanding the above-mentioned advantages over piezo actuators, piezo actuators are components in which large power losses are converted, which can cause the piezoelectric material to heat up considerably. The piezoelectric material itself has thermal limitations due to its specific Curie temperature, and the respective contacts of the electrodes also have thermal limitations.

[0085] In order to additionally counteract the heating of the movement mechanism, especially the piezo actuators, both piezo actuators can be designed with compressed room air or compressed air flowing around them, since compressed air is available in most dosing systems anyway.

[0086] If, for example due to a higher ambient temperature in the area of application of the dosing system, this compressed air or compressed air cannot dissipate enough heat from the piezo actuators to keep the piezo actuators and other temperature-sensitive areas of the dosing system permanently below a temperature that is critical for the precise operation of the dosing system, the actuators can preferably each be surrounded by a gas, preferably air, or liquid-flow cooling device.

[0087] The cooling device can preferably have a supply channel between the actuators with a number of inlets into the actuators and two off-center discharge channels with a number of outlets into the discharge channels. The cooling device can be designed as a largely closed circuit, i.e., a cool cooling stream is introduced into the dosing system, which absorbs heat while reducing the temperature of the movement mechanism and is then discharged from the dosing system.

[0088] With this design of the cooling device, consisting of one supply channel and two discharge channels, back pressure in the cooling device can be reduced. The supply channel can, for example, run centrally, essentially parallel to the actuators. However, it can preferably be integrated into the frame housing unit surrounding the actuators. The two discharge channels can be formed and arranged on the opposite outer sides of the actuators, each opposite the supply channel, so that the cooling flow can be easily guided continuously past the actuators during operation to absorb heat.

[0089] For example, the lever and the lever support of the movement mechanism cannot be separately air-flowed, but can only be surrounded by the exhaust air of the piezo actuators.

[0090] According to an advantageous embodiment of the invention, the actuators can additionally be encapsulated. For example, the actuators can be movably enclosed in a substantially cylindrical enclosure with sufficient clearance.

[0091] This allows the actuators to be exposed to a cooling stream flowing parallel to their length around the encapsulation. The cooling medium can be a gas, such as air, nitrogen, etc., or a liquid to viscous fluid, such as a cooling liquid, provided it has a sufficiently high flow velocity to dissipate the heat from the encapsulated actuators.

[0092] It is also conceivable that the gap or space between the encapsulated actuators and the housing is preferably filled with a soft but heat-conducting mass, so that the waste heat of the actuators can be released directly to the frame housing unit and there can be dissipated to the environment via the outer surface or in an increased form to the environment with forced convection, for example with a fan.

[0093] Alternatively or additionally, the actuators can each comprise at least one temperature sensor to measure or monitor the heating of the actuators and, if necessary, to regulate the operating speed accordingly to reduce the operational heating of the components. If encapsulation is present, the temperature sensor can be arranged inside or outside the encapsulation. Using the measured temperature data from the temperature sensor, the position of the tappet in the nozzle of the valve chamber or nozzle chamber can be finely adjusted as required, preferably automatically, so that the tappet always remains in the center position of the lever, even when the temperature changes, and the valve nozzle - depending on which of the above-mentioned methods is used - either precisely closes (tap tip in the sealing seat) or the nozzle is just open (tap tip at a distance from the nozzle).

[0094] Preferably, the coupling between the movement mechanism and the plunger can be a lockable coupling. This means that the two components can be connected to each other in a form-fitting manner for operation, such as screwing, clicking, or locking, particularly preferably in addition to a preload that continuously contacts the components anyway.

[0095] As mentioned, the frame housing unit with the components permanently connected to it can preferably form a "first main mass" of the dosing system. Preferably, the movement mechanism with the actuators, the lever, and the lever bearing unit can combine a second, main mass portion of the total mass of the dosing system, i.e., possibly in conjunction with other components, such as a fluidics unit, form a "second main mass" of the dosing system.

[0096] To improve the overall dispensing result or to stabilize the dynamic components of the dispensing system, the total mass of the dispensing system can be distributed essentially evenly, i.e., in essentially equal proportions, between the frame housing unit and the lever bearing unit. By judiciously distributing the total mass of the dispensing system between the two approximately equal "main masses," it can be ensured that the entire, oscillatory-coupled system does not respond at all to the high-frequency vibrations of the movement mechanism.

[0097] To provide a resilient support for the entire movement mechanism against the frame housing unit, the spring element can preferably be a disc spring assembly. The disc spring assembly can particularly preferably comprise a number of individual spring plates and / or spring assemblies. Different individual spring plates and / or spring assemblies can also be combined to form a disc spring assembly. The disc spring assembly can thus be used to preload the movement mechanism to compensate for thermal behavior, such as temperature-related deformations, etc., of the actuators.

[0098] The invention is explained in more detail below with reference to the accompanying figures using exemplary embodiments. In the various figures, identical components are provided with identical reference numerals. The figures are generally not to scale and are to be understood merely as schematic representations. They show: Figure 1a partial longitudinal section (along section line AA according to Figure 2 ) of an embodiment of a dosing system according to the invention, with a view into the interior of a housing of the dosing system, Figure 2 a top view of the embodiment from Figure 1 , for better clarity and visibility without housing, Figure 3 an enlarged, isolated plan view of a lever of the embodiment of Figure 1 , Figure 4 a longitudinal section along the section line BB through the lever according to Figure 3 , Figure 5 an enlarged, perspective, partially transparent partial view of two actuators on the lever according to Figure 1 .

[0099] Figure 1shows an overall view of a first embodiment of a dosing system 1 according to the invention for dosing a dosing medium on a workpiece in a partial longitudinal section through the dosing system 1 along an at least predominantly longitudinal direction 30L (in Figure 1 : horizontal or left-right) through the dosing system 1. This section line AA is in Figure 2 shown in a top view or top view of the dosing system 1. It runs centrally through the dosing system 1, in particular through a lever 30 of the dosing system 1, but jumps in a region of the lever 30 between two so-called actuator engagement points 36, 37 of two actuators 50a, 50b on the lever 30 in a transverse direction 30Q (which in Figure 1 into the drawing plane and into Figure 2upwards) of the lever 30 into an off-center, parallel cutting plane. Thus, at least one of the two decentralized cylindrical pins 42 forming a rotation axis R or tilt axis R of the lever 30 (see Figure 5 ) of the dosing system 1. The remaining Figure 1 The vertical direction of the dosing system 1 is also referred to below as the depth direction 30T of the lever 30. In this direction also runs a Figure 1 shown axis or symmetry axis ST centrally between the two actuators 50a, 50b which are inclined to this axis ST or to each other, wherein the symmetry axis ST vertically intersects the mentioned tilt axis R. In Figure 2 This symmetry axis ST extends into the plane of the drawing. Perpendicular to the vertical symmetry axis ST of the actuators 50a, 50b runs a horizontal axis or symmetry axis SQ, here in Figure 2from top to bottom or vice versa. Together, the axes ST and SQ form a plane of symmetry SQ, ST, relative to which the actuators 50a, 50b together form a symmetrical "V". The previously mentioned section line AA also passes perpendicularly through the dosing system 1 through the plane of symmetry SQ, ST.

[0100] In addition to a static frame housing unit 2 which largely surrounds the dosing system 1, the main components of the invention include a dynamic movement mechanism 3, 4, 5, 30, 50a, 50b (namely a lever bearing unit 3 with a lever support 4 and a fluidic positioning 5, the above-mentioned lever 30 and two actuators 50a, 50b), a spring element 21, here designed as a disc spring package 21, which braces or pre-tensions the dynamic movement mechanism 3, 4, 5, 30, 50a, 50b against the static frame housing unit 2, as well as a fluidic unit 8 which can be coupled to the fluidic positioning 5 of the lever bearing unit 3 (explanation further below), which, among other things, has a valve unit 9 which is in contact with the lever 30 and has a nozzle 12 for dosing the dosing medium in a dosing direction DR (here according to below). For better differentiation or separation, the static frame housing unit 2 is Figure 1hatched from top left to bottom right, whereas the dynamic movement mechanism 3, 4, 5, 30, 50a, 50b is hatched from bottom left to top right except for the two actuators 50a, 50b.

[0101] The lever support 4 is a part of the at least two-part lever bearing unit 3 of the dosing system 1 located within the frame housing unit 2. The fluidic positioning 5 is a part of the lever bearing unit 3 located outside the frame housing unit 2. The two parts 4, 5 are rotatably connected to one another via a rotary joint 6 outside the frame housing unit 2. The essentially elongated fluidic positioning 5 runs from the rotary joint 6 (in Figure 1right, below the frame housing unit 2), at a distance, parallel along the frame housing unit 2 or a preferably detachably coupled housing base 2' of the frame housing unit 2 (i.e. parallel along the lever support 4 spring-mounted on the inside of the frame housing unit 2) and can be pulled against the lever support 4 by means of an adjusting element 7, here an adjusting screw 7 for adjusting the preload of an ejection element 13, here a plunger 13. Together, the two parts 4, 5 thus form a type of ring construction or ring, which ring surrounds or encloses the aforementioned housing base 2' of the frame housing unit 2 (as explained later) and the spring element 21 in a ring-like manner.

[0102] The aforementioned valve unit 9 is inserted between an end section 33 of the lever 30 and the fluidic positioning device 5. The valve unit 9, in turn, comprises a hollow cylindrical valve body 10, in which the plunger 13 is movably guided. A plunger spring 15 is arranged between the valve body 10 and an end-side plunger head 14 at the opposite end of a plunger tip 16 of the plunger 13, so that the plunger 13 is resiliently mounted. The distance between the nozzle 12 and the end section 33 of the lever 30 can thus be changed by means of the adjusting screw 7, which enables precise adjustment of a plunger end position relative to a nozzle insert 12' and thus enables reliable closure of the dosing system 1. The adjusting screw 7 has a fine-thread spindle with a helical compression spring in order to be able to make a fine adjustment of the distance between the lever support 4 and the fluidic positioning 5.The adjusting screw 7 can therefore be used to ensure precise adjustment of the dosing system 1 to the properties of the nozzle 12 and the tappet 13, so that possible manufacturing tolerances or wear can be compensated.

[0103] In the area of the valve unit 9, the fluidic positioning system 5 also includes a heating device integrated into the fluidic positioning system 5, which is supplied and controlled by the electronics of the valve unit 9. The heating device itself includes a heating cartridge and a sensor to heat or warm the dosing medium for dosing as needed.

[0104] In addition to the described valve unit 9, the fluidic unit 8, which is detachably coupled to the fluidic positioning 5, comprises a dosing medium supply connection 17 for the sufficient and continuous supply or feeding of a dosing medium for the dosing system 1 from a reservoir 17r, here e.g. a dosing substance cartridge 17r, into the valve chamber 11. For this purpose, a medium supply channel or media-carrying channel (not shown) runs inside the fluidic unit 8 between the dosing media supply connection 17 and the valve chamber 11.

[0105] How Figure 1As can be seen, the fluidic unit 8 also includes a heating device, namely a heating unit 18 with a second heating zone along the media-carrying channel and a heating element 20 in the nozzle area or on the nozzle chamber 11 of the valve unit 9. The heating unit 18 is supplied via a connection 19 or a heating cable 19. This means that even with a purely passive fluidic unit, i.e. one that is not itself heated and regulated, temperature control in the nozzle area is possible. In addition, the media-carrying channel in particular can also be temperature-controlled, so that preheating of the dosing medium can be improved, which is particularly advantageous with large volume flows.

[0106] The fluidic unit 8 already mentioned above is detachably attached near the heating element 20 at an interface 5s of the fluidic positioning device 5 remote from the swivel joint. This fluidic unit 8 in turn has a medium feed channel from the dosing medium supply connection 17 to the valve chamber 11 of the valve unit 9 in order to continuously feed dosing medium from a reservoir 17r, here e.g. a dosing substance cartridge 17r, via the dosing medium supply connection 17 and the medium feed channel into the valve chamber 11.

[0107] During operation, the dosing system 1 applies a desired dosing medium portionwise from the reservoir 17r to a workpiece from a nozzle 12 in the valve chamber 11. For this purpose, at least one drop of a desired dosing medium or dosing substance, the amount of which can be precisely dosed, is dispensed in a dosing direction DR through an opening cross-section of the nozzle 12 or a nozzle insert 12' in the nozzle 12. This can be achieved by means of a rapid movement or plunger movement 30B of the plunger 13, controlled indirectly via the lever 30 and driven by the counteracting actuators 50a, 50b. The interchangeable nozzle insert 12' in the nozzle 12 of the valve chamber 11 serves to adjust the dosing quantity and shape of the drop even more specifically for different application areas.

[0108] The remaining components within the frame housing unit 2 are now described below.

[0109] The spring element 21 (already mentioned above) which braces the movement mechanism 3, 4, 5, 30, 50a, 50b in the frame housing unit 2 is located inside the frame housing unit 2 at the bottom of the housing base 2' of the frame housing unit 2 and braces the lever 30, which is mounted on the lever support 4 so as to be rotatable about the rotation axis R, against an upper section or frame of the frame housing unit 2 via the two actuators 50a, 50b located on the lever 30 near the tilt axis R. With the bracing, the two piezoelectric actuators are pre-tensioned via the lever bearing unit, which is necessary to avoid tensile stresses during dynamic operation. At the same time, dynamic vibrations are greatly attenuated due to the relatively inertial mass of the frame housing unit 2, and thermal differences orTemperature gradients – which can arise due to the highly dynamic movement mechanisms 3, 4, 5, 30, 50a, 50b – are decoupled from the frame housing unit 2 of the dosing system 1 and coupled or equated with the valve unit 9. As a result, these effects have almost no influence on the dosing process of the dosing medium from a nozzle 12 of the valve unit 9. In the exemplary embodiment of the dosing system 1 according to the invention shown here, the spring element 21 is a disc spring assembly 21 with, for example, four individual spring plates mounted vertically one above the other, which are spring-mounted one below the other and whose spring forces add up. The construction is pressed together over a large area, which causes high damping of the disc spring assembly and thus also leads to a reduction in the tendency of the frame housing unit to vibrate against the lever bearing unit.

[0110] As already mentioned, the spring element 21 can be connected to the housing base 2', e.g., sheet metal, plate, etc., of the frame housing unit 2, e.g., screwed, on the underside. It can therefore be firmly coupled on one side, in this case, the underside. Alternatively, the spring element could also simply be clamped between them.

[0111] In order that the two parts 4, 5 can be clamped against each other at a distance or with a gap to the housing base 2', enclosing or encompassing the disc spring assembly 21 in a ring-like manner, the housing base 2' has Figure 1 There are 21 cutouts (to the side and downwards) to the right and left of the disc spring assembly.

[0112] The lever support 4 rests on the top side of the spring element 21 and, as mentioned, is pressed against the spring element 21 by the actuators 50a, 50b.

[0113] The lever support 4 has two lateral (in Figure 1(in the direction of the drawing plane) "legs" with upwardly opening semicircular recesses. Between the legs, an interior space is formed which is adapted to the lever 30 with the necessary freedom of movement for partially accommodating the lever 30. In the side view according to Figure 1 Only one of the two said legs of the lever support 4 is visible, since the two legs - viewed from this direction - lie one behind the other. In the recess of the visible (here front) leg is one of the two cylindrical pins 42 forming the rotation axis R (see Figure 5 ) can be seen. In order to better recognize the structure of this part of the dosing system 1, the section line BB running longitudinally through the isolated lever 30 in Figure 3 the cutting line course (in the manner of a "single rectangular pulse"), as the cutting line AA mentioned above from Figure 2 uses.

[0114] As in Figure 5 As can be seen, each of the said cylindrical pins 42 rests laterally approximately with an outer half 42a (along the cylindrical pin axis) on one of the legs of the lever support 4 and simultaneously holds (rotatably) with the other, inner half 42b the lever 30 in the interior of the lever support 4. For this purpose, the cylindrical pins 42 each protrude into a lateral, transverse (in a transverse direction 30Q) in the lever 30, U-shaped recess 41 (explanation below) of the lever 30, which recess 41 in the plan view of the lever 30 in Figure 3 is indicated by dashed lines and in Figure 4 shown from the side.

[0115] The shape of the lever 30 can be described as a two-sided, three-dimensional, asymmetrical force converter in the manner of a "barrier boom" (with counterweight). Specifically, the lever arm 31 of the lever 30 comprises, in its longitudinal direction 30L, a voluminous, rather solid, roughly cuboid-shaped section on approximately one half and a narrow, as light as possible, elongated stem or "cantilever" on the other half. A (here in Figure 3 right) half of the cuboid section belongs to a shorter lever arm side 32 of the two-sided lever arm 31. The other (here in Figure 3The left half of the cuboid section, together with the adjoining elongated boom, belongs to a longer lever arm side 35 of the two-sided lever arm 31. In between lies the rotation axis R of the lever 30, next to which the two actuators 50a, 50b of the movement mechanism 3, 4, 5, 30, 50a, 50b act on the lever 30 at the actuator engagement points 36, 37. In this case, a first (in Figure 1 and 2 left) actuator 50a at a first (here left) recessed or recessed actuator engagement point 36 of the first lever arm side 35 of the two-sided lever arm 31, which is recessed or recessed in the interior of the lever 30, and a second (here right) actuator 50b at a second (here right) equally recessed or recessed actuator engagement point 37 of the second lever arm side 32 of the two-sided lever arm 31 (for the position of the actuator engagement points 36, 37 see also Figures 3 to 5 ).

[0116] The two actuators 50a, 50b are therefore in a normal arrangement of the dosing system 1, as shown here in Figure 1 shown, on a (lever) top 40 (in Figure 1 in the depth direction 30T above), in the cuboid section on both sides of the rotation axis R of the lever 30 directly (on a cylindrical pin 36z, 37z of the actuator engagement points 36, 37, each of which is explained below) on the lever 30.

[0117] Based on the Figure 5 in perspective view of the lever 30, shown partially transparent, and a part of the two actuators 50a, 50b, it is shown how the two actuators 50a, 50b or their fronts 54 engage or abut precisely on the lever 40 in order to tilt it by a few degrees about the rotation axis R or tilting axis R, ie how they transmit a tilting moment or a longitudinal deflection to the lever 30 in their respective direction of action 52a, 52b. As can be seen from the enlarged section in Figure 5As can be seen, the actuators 50a, 50b with their directions of action 52a, 52b are tangential to a circle K of the points of action (or actuator points of action 36, 37), so that the directions of action 52a, 52b are each perpendicular to a radial connecting line V a , V b to the common axis of rotation R in the center of the circle K. Since the directions of action 52a, 52b act tangentially on the circle K, a longitudinal deflection, ie a tilting moment of a respective actuator 50a, 50b, whose front 54 thereby rotates with the lever 30 by a few degrees minimally along the circle K around the axis of rotation R (around the Figure 5shown tangential position or center position P 0 of the lever) moves downwards or upwards in an arc, only a minimal transverse movement. If the actuators 50a, 50b or their directions of action 52a, 52b were to act further up or down along the circle K, the same deflection of a few degrees along the circle K would cause a significantly greater transverse movement of the front 54 of the respective actuator 50a, 50b. This otherwise significantly more arcuate circular orbital movement or pendulum movement along the circle K can be reduced to a longitudinal deflection that is as straight as possible by means of the tangential arrangement of the directions of action 52a, 52b on the circle K around the rotation axis R.

[0118] On one (lever) underside (in Figure 1In the depth direction 30T below), the lever 30 rests in the cuboid section on the rotation axis R between the actuator engagement points 36, 37 indirectly (with the outer halves 42a of the cylindrical pins 42) on the lever support 4 and is in contact with the plunger head 14 of the plunger 13 in the end section 33 of the elongated arm. A further bore 34 is formed in the lever 30 at the end section 33 of the arm of the lever 30. It serves to insert a permanent magnet and thus to determine the position of the lever 30 with a HALL sensor attached to the lever bearing unit 3.

[0119] In order for the actuators 50a, 50b to be positioned for the first time below a rotational axis plane XR at the actuator engagement points 36, 37 inside the lever 30 (and not already superficially at the top side 40 of the lever 30), the lever 30 has wedge-shaped downwardly tapered wedge recesses 39 that begin at the top side 40 and extend to the actuator engagement points 36, 37 inside the lever 30. The respective deepest points or locations of the wedge recesses 39 in the lever 30 define a first actuator engagement point 36 for a first actuator 50a (in Figure 1 the left actuator) and a second actuator engagement point 37 for a second actuator 50b (in Figure 1the right actuator). The wedge recesses 39 are designed such that the fronts or tips 54 of the actuators 50a, 50b, which are arranged at an angle to one another and which are also wedge-shaped when the dosing system 1 is assembled as intended, can be accommodated therein or are accommodated with some play.

[0120] As particularly in Figure 5As can be seen, the actuator engagement points 36, 37 are constructed from the two previously mentioned cylindrical pins 36z, 37z, against which the actuators 50a, 50b rest with their fronts 54 and can roll on the cylindrical pins 36z and 37z. The front sides of the fronts 54 of the actuators 50a, 50b are each concavely adapted to the cylindrical pins 36z, 37z with a relatively larger radius. The core bores are formed in the transverse direction 30Q continuously from one long side to the other long side of the lever 30 and are almost completely filled by the cylindrical pins 36z, 37z (see Figure 5) and intersect an end region of the wedge recesses 39, so that the core bores are partially open upwards to the wedge recesses 39. The radius of the core bores is adapted to the cylindrical pins 36z, 37z, so that a secure hold is guaranteed and the actuators 50a, 50b with their fronts 54 on the fixed cylindrical pins 36z, 37z, ensure a low-friction relative rolling movement.

[0121] Centrally in the longitudinal direction 30L, diagonally above between the aforementioned core holes, are the above-mentioned recesses 41 for the other aforementioned cylindrical pins 42, by means of which the lever 30 is pivotably mounted about the rotation axis R in the interior space between the two legs of the lever support 4. The radius of the recesses 41 is also somewhat larger than that of the cylindrical pins 42, so that a "fixed" target position is also present while ensuring a low-friction relative rolling movement. The recesses 41 begin, viewed in the transverse direction 30Q, outside the wedge recesses 39 in opposite, spaced-apart edge regions of the lever 30 (see Figure 3 ). In the depth direction 30T of the lever 30, they extend from the underside to above a so-called attack axis plane XA of the lever 30 (see Figure 4). The plane of attack axis XA is defined by the actuator attack points 36, 37, which are located on the surfaces of the cylindrical pins 36z, 37z. In a central position P 0 of the lever 30, the plane of attack axis XA is aligned horizontally. The cylindrical pins 42 are (as in Figure 5 can be seen) are received approximately halfway along their length with the inner half 42b in the recesses 41 (in which they rest on the top or with their upper side, as mentioned above) and rest with the other outer half 42a with its underside on the legs in the semicircular, upwardly open recesses of the lever support 4. The lever 30 can therefore be very easily inserted into the lever support 4 from above during assembly in order to achieve this operating state, before the other components are placed or mounted.

[0122] In the operating state, the lever 30 is arranged on or in the lever support 4 in a very space-saving manner, since in its depth direction 30T it projects into the interior between the legs of the lever support 4 with just enough play up to approximately half its height or depth or is received therein. With this type of bearing, it can be tilted as intended about the tilt axis R without direct contact with the lever support 4 by at least a few degrees, namely preferably between +-0.1° and +-5° (degrees). A tilt angle of +-0.5° is particularly preferred. Its axis of rotation R, which runs transversely through the lever 30, runs off-center in the longitudinal direction 30L of its center of gravity.

[0123] In order to reduce the weight of the lever 30, in particular of its elongated arm, as much as possible, the lever 30 has, in addition to the (in Figure 4The wedge recess 39 near the boom (left) has four bores 38 or recesses 38. The bores 38 are circular, of different sizes, and decrease in diameter towards the end section 33, as they are adapted to the overall flatter shape of the lever 30 towards the end section 33. They are slightly spaced from one another and, viewed in the transverse direction 30Q, run continuously through the lever 30. The bores 38 functionally ensure maximum weight reduction of the lever 30 without compromising the stability of the lever 30. The above phrase "flattening" means that the lever 30, beginning with the wedge recess 39 near the boom in the longitudinal direction 30L towards the end section 33, has a bottom side that runs obliquely towards the top side 40, i.e., it becomes less deep or flatter in the depth direction 30T.As a result, the end section 33 in contact with the plunger head 14 at the end of the elongated arm in the central position P 0 of the lever 30 is at exactly the same height as the upper end of the recesses 41 in the lever 30 for the above-mentioned cylindrical pins 42 in the voluminous section of the lever 30. In other words, the end section 33 in the central position P 0 of the lever 30 is therefore exactly in the rotation or rotation axis plane XR .

[0124] For this purpose, a lever bearing end cap (not shown for clarity) can be placed on top of the lever support 4, at least enclosing the cylindrical pins 42 at the top, as an upper end cap or partially open cover with holes for the actuators 50a, 50b. In order to almost completely surround or enclose the lever 30 from above, such a lever bearing end cap can have approximately the same size and shape as the lever support 4 below. It can have through-openings for the actuators 50a, 50b running diagonally from top to bottom, through which the actuators 50a, 50b with their cylindrical transmitters 53 (in the direction of action 52a, 52b behind the fronts 54 of the actuators 50a, 50b) run in order to be able to engage the actuator engagement points 36, 37 on the lever 30.With a lever support 4 and a lever bearing closure above it, the lever 30 is movably mounted therein, largely shielded from the rest of the dosing system 1.

[0125] Above the lever 30, the two actuators 50a, 50b are arranged at an angle to one another and symmetrically aligned to the axis ST, which, as mentioned, rest with their concave front sides of the tips or fronts 54 on the cylindrical pins 36z, 37z of the actuator engagement points 36, 37 on the lever 30.

[0126] The two identical actuators 50a, 50b or piezo actuators 50a, 50b each comprise a plurality of piezo elements 51 or "piezo plates" stacked as usual to form a piezo stack, with which a mechanical movement in the longitudinal direction or direction of action 52a, 52b of the actuators 50a, 50b, i.e. a change in length normal or perpendicular to the surface of the piezo elements 51 along the longitudinal axis 52a, 52b of the respective actuator 50a, 50b, is generated by applying an electrical voltage by means of the so-called "inverse piezo effect".

[0127] The encapsulated actuators 50a, 50b are each embedded in a recess 56 of the frame housing unit 2, which is sealed with O-rings 57, around the piezo elements 51 and are cooled during operation by means of a cooling device 60 of the dosing system 1 integrated in the frame housing unit 2 within the recess 56 in the frame housing unit 2.

[0128] The cooling device 60 or the cooling channel system 60 comprises a supply channel 61 for introducing a cooling medium for cooling the piezo elements 51 centrally between the actuators 50a, 50b as well as two discharge channels 63a, 63b for the parallel, continuous subsequent discharge of the cooling medium laterally, in the longitudinal direction 30L (in Figure 1 left and right) next to the piezo elements 51 or actuators 50a, 50b. From a source coupled to the dosing system 1 at the upper section or frame of the frame housing unit 2, the cooling medium flows in the feed channel 61 parallel to the actuators 50a, 50b in a (in Figure 1downwards) cooling flow direction 60i to the transformers 53 of the actuators 50a, 50b. Immediately above the transformers 53 - sealed by two O-rings 57 for sealing the gap between the recess 56 and an outer skin of the hermetically encapsulated actuators 50a, 50b - it is directed in a direction opposite to the direction of action 52a, 52b of the actuators 50a, 50b to the end connections 55 of the actuators 50a, 50b (in Figure 1obliquely upwards) and then flows vertically (obliquely downwards) via lateral inlets 62 of the feed channel 61 into the recess 56 of the piezo elements 51 of the actuators 50a, 50b which are arranged obliquely to one another, so that the piezo elements 51 of the actuators 50a, 50b are surrounded by the cool cooling medium. The cooling medium propagates evenly from an inner side centrally between the actuators 50a, 50b (slightly diagonally downwards) outwards along the meandering outer skin of the hermetically housed stacked piezo elements 51 or around the piezo elements 51, absorbs the heat generated by the actuators 50a, 50b and then flows via lateral outlets 64 from the recess 56 into the two discharge channels 63a, 63b (right and left) on the outer sides of the actuators 50a, 50b.There, in the two lateral discharge channels 63a, 63b, the heated cooling medium is sucked in and discharged (upward) in an (upward) cooling flow direction 60o to the two outlets of the discharge channels 63a, 63b of the cooling channel system 60 on the upper section or frame of the frame housing unit 2. By means of the single central introduction and the bilateral parallel discharge of the cooling medium on the two outer sides of the actuators 50a, 50b, which are spaced apart from each other in the longitudinal direction 30L, a back pressure of the cooling medium in the cooling channel system 60 can be minimized and thus a cooling performance or cooling effectiveness of the cooling channel system 60 can be maximized.

[0129] In addition to the end connections 55 for controlling the current or voltage supply of the actuators 50a, 50b, the actuators 50a, 50b each comprise a temperature sensor 65 which provides temperature data by means of which, among other things, the cooling capacity of the cooling channel system 60 can be regulated or controlled.

[0130] In summary, the dosing system 1 can be structurally and functionally divided or subdivided essentially into two units 2, 60, 3, 4, 5, 30, 50a, 50b, which are spring-mounted relative to each other via the spring element 21, as follows. A "static" unit 2 comprises, among other things, the frame housing unit 2 and the housing base 2' of the frame housing unit 2. In addition, it can comprise at least the integrated cooling device 60, a control board for controlling the dosing system 1, an insulation board, a connection board, possible connections, in particular for the source and the outputs of the cooling medium, and a power supply for the dosing system 1.

[0131] A "dynamic" unit 3, 4, 5, 30, 50a, 50b or movement mechanism 3, 4, 5, 30, 50a, 50b comprises at least the lever bearing unit 3 with the lever support 4 and the fluidic positioning unit 5, the lever 30, and the two actuators 50a, 50b. Additionally, it can be coupled to the valve unit 9 and the fluidic unit 8 at the fluidic positioning unit 5 and, if appropriate, comprise a permanent magnet on the lever 30 and a corresponding HALL sensor on the lever bearing unit 3 for determining the position of the lever 30. Either a dosing agent cartridge 17r or simply a supply line or hose from a dosing agent tank can be connected to the fluidic unit 8 at the dosing agent supply connection 17.

[0132] The two aforementioned units can advantageously be dimensioned and weighted such that they have essentially the same mass, i.e., the total mass of the dosing system 1 is divided essentially equally into the "static" unit and the "dynamic" unit. This achieves - as intended by the invention - an even more stable, higher-quality dosing result with a particularly high dosing speed or dosing frequency, since the vibrations of the two units are mutually attenuated or compensated. If the fluidic unit 8, as in Figure 1 shown, is designed with a dosing cartridge 17r, the content of which changes with the dosage, this can be taken into account in the distribution of the total mass, for example in such a way that the main masses of the total mass balance each other out at least on average.

[0133] Finally, it should be noted once again that the devices described in detail above are merely exemplary embodiments that can be modified in a variety of ways by those skilled in the art without departing from the scope of the invention. For example, the dosing system could also be structurally modified in such a way that a correspondingly designed and arranged tension spring could be used as the spring element. Furthermore, the use of the indefinite articles "ein" or "eine" does not preclude the possibility that the relevant features may be present multiple times. List of reference symbols

[0134] 1Dosing system 2Frame housing unit 2'Housing base 3Lever bearing unit 4Lever support 5Fluidic positioning 5sInterface between fluidic positioning and fluidic unit 6Swivel joint 7Adjustment element / adjusting screw 8Fluidic unit 9Valve / valve unit 10Valve body 11Valve chamber / nozzle chamber 12Nozzle 12'Nozzle insert 13Ejection element / plunger 14Plunger head 15Plunger spring 16Plunger tip 17Dosing medium supply connection 17rReservoir / dosing medium cartridge 18Heating unit 19Connection / heating cable 20Heating element 21Spring element / disc spring package 30Lever 30BPlunger movement 30LLongitudinal direction of the lever 30QTransverse direction of the lever 30TDepth direction of the Lever 31Lever arm,two-sided 32 shorter lever arm side 33 end section 34 bore (for permanent magnet) 35 longer lever arm side 36 first actuator engagement point 36 first cylindrical pin of the first actuator engagement point 37 second actuator engagement point 37 second cylindrical pin of the second actuator engagement point 38 bores / through bores / recesses 39 wedge recesses 40 (lever) top of the lever 41 recess for cylindrical pins in the lever support 42 cylindrical pins 42a outer half of the cylindrical pin 42b inner half of the cylindrical pin 50a, 50b actuators / piezo actuators (encapsulated here) 51 piezo elements 52a first direction of action / longitudinal axis of the first actuator 52b second direction of action / longitudinal axis of the second actuator 53 actuator transmitter 54 fronts / Actuator tips 55 Actuator connections 56 Recess for the piezo actuators 57 O-ring 60 Cooling device / cooling channel system 60i, 60o Cooling flow directions 61 Supply channel 62 Inlets of the supply channel into the actuators 63a, 63b Discharge channels,two 64outlets of the discharge channel from the actuators 65temperature sensor, A-A Section line through the dosing system B-B Section line through the lever DR Dosing direction K Circle of actuator engagement points P 0 Center position R Rotation / tilt axis ST First symmetry axis of the symmetry plane of the actuators SQ Second symmetry axis of the symmetry plane of the actuators V a First connecting line V b Second connecting line XA Engagement axis plane XR Rotation / turning axis plane

Claims

1. A metering system (1) for metering a metered medium comprising - a frame housing unit (2), - a lever mounting unit (3) which is supported on the frame housing unit (2) comprising a lever mount (4), - a, preferably asymmetrical, lever (30) which is supported rotatably by means of the lever mount (4) about a tilt axis (R) comprising a two-sided lever arm (31) extending substantially in a longitudinal direction (30L) of the lever (30), wherein one lever arm side (35), preferably the longer lever arm side (35), has a first actuator engagement point (36) close to the tilt axis and is in contact remotely from the tilt axis at an end portion (33) with an ejection element (13), preferably a ram (13), and wherein the other lever arm side (32), preferably the shorter lever arm side (32), has a second actuator engagement point (37) close to the tilt axis, - two actuators (50a, 50b), which, during operation, exert a tilting moment in opposite directions on the lever (30) at the first and second actuator engagement point (36, 37), wherein together, the lever mounting unit (3), the lever (30), and the two actuators (50a, 50b) form a movement mechanism (3, 4, 5, 30, 50a, 50b), which is braced on the frame housing unit (2) by means of at least one spring element (21), preferably a disc spring set (21), wherein the spring element (21) is preferably arranged so that it braces the lever mounting unit (3) against the frame housing unit (2) via the lever (30) as well as via the two actuators (50a, 50b),characterized in that the actuators (50a, 50b) are placed obliquely to one another in a V-shaped manner.

2. The metering system according to claim 1, wherein the two actuators (50a, 50b) are located on a common longitudinal side of the lever (30).

3. The metering system according to claim 1 or 2, wherein the actuators (50a, 50b) are placed obliquely to one another in a V-shaped manner, maximally at a 150° angle, preferably maximally at a 120° angle, even more preferably maximally at a 90° angle, particularly preferably maximally at a 60° angle, and most preferably maximally at a 30° angle.

4. The metering system according to one of the preceding claims, wherein the actuator engagement points (36, 37) on the lever (30) for the actuators (50a, 50b) are not located in a plane of the tilt axis (R).

5. The metering system according to one of the preceding claims, wherein the lever (30) is formed and arranged in such a way that the actuator engagement points (36, 37) are positioned in the lever (30) further away from a longitudinal side of the lever (30) facing the actuators (50a, 50b), than the tilt axis (R), on which tilt axis (R) the lever (30) is supported rotatably.

6. The metering system according to one of the preceding claims, wherein the actuators (50a, 50b) engage with the actuator engagement points (36, 37) in such a way that in a central position (P0) of the lever (30), a longitudinal axis (52a, 52b) of the actuators (50a, 50b) is in each case substantially perpendicular to a respective connecting line (Va, Vb) between the respective actuator engagement point (36, 37) and the tilt axis (R).

7. The metering system according to one of the preceding claims, wherein the actuators (50a, 50b) are arranged tangentially on a circle (K) about the tilt axis (R) on the actuator engagement points (36, 37) in such a way that they substantially perform a straight movement during operation for metering a metered medium in response to an ejection and withdrawal movement.

8. The metering system according to one of the preceding claims, wherein the lever (30) has an inhomogeneous mass distribution, wherein a mass of the lever (30) is preferably distributed relative to the tilt axis (R) along the lever (30) in such a way that the lever (30) as a whole, based on the tilt axis (R), has a smallest possible (mass) moment of inertia.

9. The metering system according to one of the preceding claims, wherein the lever (30) has a plurality of recesses (38), preferably transversely running through bores (38), for weight reduction purposes.

10. The metering system according to one of the preceding claims, wherein a total mass of the metering system (1) is divided substantially evenly to the frame housing unit (2) and the lever mounting unit (3).

11. The metering system according to one of the preceding claims, wherein the lever mounting unit (3) is of multi-part construction, in particular comprises a fluidic positioning (5) for a fluidic unit (8) of the metering system (1) in addition to the lever mount (4), wherein the lever mount (4) is preferably connected in a rotatable manner to the fluidic positioning (5) via a rotary joint (6), and / or wherein the lever mount (4) and the fluidic positioning (5) are supported in a mechanically adjustable manner against one another.

12. The metering system according to one of the preceding claims, wherein the lever mounting unit (3) comprises a ring construction (4, 5), which encloses a portion (2') of the frame housing unit (2) in a ring-like manner by leaving at least one gap, and wherein the lever mounting unit (3) is preferably supported on the frame housing unit (2) in a displaceable manner by means of the spring element (21), which is preferably arranged in a gap between the lever mounting unit (3) and the portion (2') of the frame housing unit (2), and / or wherein the ring construction (4, 5) preferably comprises a (the) rotary joint (6), and the lever mount (4) of the lever mounting unit (3) is coupled to the fluidic positioning (5) in a mechanically adjustable manner via the lever (30) and the ram (13) for adjusting a ramnozzle distance on a side of the fluidic positioning (5) remotely from the rotary joint by means of an adjusting element (7), in particular an adjusting screw (7).

13. The metering system according to one of the preceding claims, wherein the actuators (50a, 50b) are in each case formed in an encapsulated manner, and / or wherein both actuators (50a, 50b) in each case comprise at least one temperature sensor (65).

14. The metering system according to one of the preceding claims, wherein a cooling device (60), through which gas, preferably air, or liquid flows, in each case surrounds the actuators (50a, 50b), wherein the cooling device (60) preferably has a feed channel (61) between the actuators (50a, 50b) comprising inlets (62) into the actuators (50a, 50b) and two eccentric discharge channels (63a, 63b) comprising outlets (64) into the discharge channels (63a, 63b).