Method and device for producing coated wires using a stripping device for stripping excess coating material from a wire wetted with coating material

Abstract

The invention relates to a method and a device for producing coated wires (3) using a stripping device (1) for stripping excess coating material (2) from a wire (4), wherein: the stripping device (1) has a main part (4) with a stripping passage (5) for the wire (3) and a stop unit (7) arranged downstream of the main part (4) in the wire conveying direction (6); the stop unit (7) has a first stop face (8); the main part (4) has a second stop face (9); the second stop face (9) faces the first stop face (8) in the intended state; at least some portions of the first stop face (8) are frictionally connected to the second stop face (9) during use as intended; the main part (4) is mounted such that it can be moved perpendicular to the wire conveying direction (6); and the first stop face (8) or the second stop face (9) has a convex curvature (10).

Description

[0001] Method and apparatus for producing coated wires with a stripping device for removing excess coating material from a wire wetted with coating material

[0002] The invention relates to a stripping device for removing excess coating material from a wire wetted with coating material, comprising:

[0003] - a base body with a stripping feedthrough for the wire, wherein the wire is passed through the stripping feedthrough in the intended state and into a

[0004] Wire is conveyed in the direction of transport; and

[0005] - a stop unit arranged in the wire conveying direction after the base body; wherein the stop unit has a first stop surface, wherein the first stop surface is facing the base body in the intended state, wherein the base body has a second stop surface, wherein the second stop surface is facing the first stop surface in the intended state.

[0006] The invention further relates to an application unit for applying at least one layer of a coating material to a wire, comprising:

[0007] - a wetting unit for applying the coating material, wherein the wetting unit has a wetting unit body with a wetting feedthrough for the wire.

[0008] Furthermore, the invention relates to methods for the production of coated wires.

[0009] Devices and systems for the production of coated wires, such as enamelled wires, with stripping devices and application units are already known from the prior art. Enamelled wires are understood to be enamel-insulated metal wires, for example, made of copper or aluminum. Due to the enamel coating, good insulation of an electrical conductor from an adjacent conductor or the winding support can be achieved. Coated wires, such as enamelled wires, are used in particular for the production of electrical windings, which serve for current conduction, voltage conversion, field generation, and field deflection. These windings are therefore, in turn, a central component of electric motors, transformers, and generators. Not least due to the rise of e-mobility, both the demand for and the requirements for coated wires are increasing.The coatings known in the prior art consist essentially of film-forming resins and solvents.

[0010] Such systems include, among other things, a unit for applying an insulating coating material and an oven for curing the applied layer. The wire is typically conveyed through the system by means of one or more support and / or deflection rollers.

[0011] A device and a method for processing a wire with a coating device are known, for example, from EP 2 930 723 B1. Liquid lacquer is applied to a wire by means of the coating device. Dissolved polymers in the lacquer chemically crosslink after application and characterize the hardening process of the lacquer. The lacquer is applied via conically shaped wiping nozzles, which are continuously supplied with fresh lacquer by means of a feed pump. A lacquer film of a preset thickness is then evenly applied to the wire surface. An oven is provided for drying the lacquer.

[0012] An inline process plant for the production of enamelled wire is known, for example, from DE 3 118 830 Al .

[0013] A multi-stage furnace system for the production of enamelled wires is known, for example, from AT 284 931 B.

[0014] Typically, bare wire is supplied as continuous material on a spool or produced by drawing it from a raw material and fed into the system. A roller is also provided, on which the wire rests and by which it is fed. A coating unit, usually comprising one or more coating stations, is typically used to apply the coating material. Each coating station has a reservoir for the material to be applied, as well as a device for wetting the wire and a device for removing excess coating material, such as a coating nozzle. The wire is completely coated with the material. Excess coating material is then wiped off the wire to achieve the most homogeneous layer possible. Subsequently, the wire, along with the coating, is conveyed into an oven to dry, harden, and solidify the coating material.The coating process can be repeated several times to achieve the desired layer thickness or a sequence of different materials.

[0015] Generally, a distinction is made between vertical and horizontal coating systems. In vertical systems, the wire is conveyed vertically during coating, while in horizontal systems, the wire is conveyed (predominantly) horizontally during coating. While horizontal systems offer advantages over vertical systems in terms of improved accessibility and maintainability, lower operating costs, lower energy consumption, and higher throughput, the cross-sectional area of ​​coated wires produced on horizontal systems is limited.

[0016] A key requirement for coated wires is a homogeneous coating thickness, which is often difficult or impossible to achieve due to widely varying thicknesses and geometries of the bare wires, differing properties and desired coating thicknesses, and vibrations transmitted from the machine to the wire. For example, if the wire is not guided centrally through the stripping device, the resulting coating will be asymmetrical or oval. If the wire's passage through the stripping device changes over time, for instance due to minor process variations or wire vibrations, the coating thickness can also vary accordingly. This can lead to inhomogeneous coatings along the wire's longitudinal axis.

[0017] An inhomogeneously thick coating can, in turn, lead to insufficient or inhomogeneous curing, skin formation, blistering, and residual solvent content in the coating during the subsequent oven drying process. Furthermore, it can result in stress breakdowns and partial discharges, which occur particularly in areas of insufficient coating thickness. Such stress breakdowns can damage or even cause the failure of larger assemblies, thus leading to drastic consequences.

[0018] Systems for the production of coated wires must therefore be precisely adjusted to the cross-section and material of the respective wire, the coating material, the coating thickness, and other parameters such as the wire feed speed. Such adjustment is time-consuming and must be carried out by specially trained personnel, usually in several iterations. Frequent manual fine-tuning is hardly feasible within a production process. Even with ideal initial settings, minor fluctuations can occur that negatively affect the coated wire. External influences such as temperature or humidity fluctuations can, for example, cause slight variations in wire deflection.Furthermore, rapid changes in the exact orientation of the wire, such as wire vibrations, cannot be compensated for by manual adjustment. Existing systems and processes are generally inadequate for responding to time-varying conditions that negatively affect the homogeneity of the coating. Therefore, the object of the invention is to mitigate or completely eliminate the disadvantages of the prior art. In particular, the object of the invention is to provide a stripping device for removing excess coating material from a wire wetted with coating material, an application unit for applying at least one layer of a coating material to a wire, and a method for producing coated wires that are robust against external influences and process fluctuations and ensure a homogeneous layer thickness.

[0019] This problem is solved by a stripping device of the type mentioned above, wherein the first stop surface is at least partially frictionally connected to the second stop surface when used as intended, wherein the base body is mounted to be displaceable normal to the wire conveying direction, and wherein the first stop surface or the second stop surface has a convex curvature.

[0020] The problem is also solved by an application unit of the type mentioned above, wherein the application unit has a stripping device according to the invention for stripping excess coating material from the wire, wherein the wire is passed through the wetting feedthrough and the stripping feedthrough in the intended state.

[0021] The problem according to the invention is also solved by a method for producing coated wires with an application unit according to the invention, comprising the steps:

[0022] - Conveying a wire in a wire conveying direction towards the application unit;

[0023] - Applying a layer of the coating material to the wire using the wetting unit;

[0024] - Removing excess coating material from the wire using the stripping device;

[0025] - Displacement and / or tilting of the base body by a force transmitted from the coating material to the base body, such that a principal axis of the wire coincides with a principal axis of the stripping feedthrough.

[0026] The stripping device for removing excess coating material from a wire wetted with coating material has a base body with a stripping opening for the wire. The wire may be made of, for example, copper and / or aluminum. The uncoated wire may be referred to as bare wire. The wire has a principal axis (also referred to as the longitudinal axis) and a cross-section normal to the principal axis. The cross-section may be, for example, round, in particular circular or oval. Alternatively, the cross-section of the wire may be rectangular, in particular square. For example, the cross-section of the wire may be substantially rectangular or square and have rounded edges. For example, quarter-circle-shaped transition contours may be provided to avoid sharp edges. A cross-sectional area (normal to the longitudinal axis) of the wire may, for example, be between 0.8 mm². 2up to 15 mm 2 , especially between 0.8 mm 2 up to 8 mm 2 The wire's width can be, for example, between 1 mm and 7 mm. The wire's thickness (normal to the width) can be, for example, between 0.8 mm and 2 mm. The aspect ratio between the wire's width and thickness can be, for example, between 1 and 8.

[0027] The wire, coated with coating material, is passed through the stripping feedthrough in its intended state and conveyed in a wire conveying direction. This strips excess coating material from the wire. For example, the wire can be conveyed in the wire conveying direction by means of one or more support rollers. The support roller can be rotatably mounted about a support roller axis. The support roller axis is perpendicular to the wire conveying direction. The support roller can, for example, have a smooth surface. The support roller can be configured to deposit several wires or several wire coatings parallel to each other and convey them in the wire conveying direction. The wire conveying direction can lie essentially in a horizontal plane. Alternatively, the wire conveying direction can lie essentially in a vertical plane.

[0028] The wire conveying direction can deviate locally from a longitudinal axis of the wire. For example, the wire conveying direction can be defined by the support roller and another support roller on which the wire rests. The wire can exhibit deflection between two support points (for example, on the support rollers). For example, the wire can exhibit oscillation or vibration, which can cause the main axis of the wire or a wire cover to deviate locally from the wire conveying direction. The wire is conveyed on average in the wire conveying direction, whereby the main axis of the wire lies on average in the wire conveying direction and can deviate locally and / or temporarily from the (average) wire conveying direction.

[0029] The stripping device has a stop unit arranged downstream of the base body in the wire conveying direction. The stop unit has a first stop surface, which, in its intended state, faces the base body. The base body has a second stop surface, which, in its intended state, faces the first stop surface. According to the invention, the first stop surface is frictionally connected to the second stop surface, at least partially, when used as intended, with the base body being mounted so as to be displaceable perpendicular to the wire conveying direction, and with either the first or the second stop surface having a convex curvature.

[0030] The stripping of excess coating material from the wire transmits an axial force to the base body, acting along the wire feed direction. This axial force presses the base body against the stop unit, creating a frictional connection between the first and second stop surfaces. The stop unit thus acts as a stop for the base body in the wire feed direction. Under normal use, the base body has no translational freedom of movement in the wire feed direction, as axial movement is limited by the stop unit and the transmitted axial force presses the base body against it. Without this axial force, i.e., without wire and without stripped excess coating material, the base body and the stop unit can exist separately.The base body may, for example, have no mechanical connection to the stop unit except for friction. For example, the base body may be separate from the stop unit. For example, the stop unit may not be positively connected to the base body. For example, no fasteners, such as screws, bolts, or rivets, may be provided for attaching the base body to the stop unit. The base body may, during intended use (i.e., in the case of a wire being inserted and during...),

[0031] (Scraping off excess coating material) must be connected to the stop unit exclusively by friction.

[0032] In the case of an asymmetrical passage of the wire through the stripping device, the stripped excess coating material transmits a radial force to the base body in addition to the axial force. The radial force acts normal to the axial force. In the case of round wires, the radial force can act radially outwards with respect to the wire's cross-section. The radial force can also act radially outwards in the case of flat wires, whereby, due to the non-rotationally symmetric cross-section of flat wires, the radial forces occurring in different directions normal to the axial force can be of different magnitudes. In the case of a flat wire, the radial force can essentially be composed of two force components acting normal to each other. The flat wire can, for example, have an essentially rectangular cross-section with a length and a height.A first force component can act along the length of the cross-section, while a second force component can act perpendicular to it along the height of the cross-section. The two force components result in a radial force, which, due to the addition of the two force components, can in turn have any direction perpendicular to the axial force.

[0033] Due to the (exclusively) frictional connection between the stop unit and the base body, the base body can be displaced relative to the stop unit and perpendicular to the wire feed direction. The base body can be displaced at least in one direction perpendicular to the wire feed direction. Preferably, in the case of a horizontal wire feed direction, the base body can be displaced at least vertically. The stop unit can have a guide to prevent horizontal displacement of the base body. Optionally, the base body can also be displaced in a second direction perpendicular to the first direction and perpendicular to the wire feed direction. The base body can therefore have at least one, optionally two, translational degrees of freedom. The radial force causes a displacement of the base body perpendicular to the wire feed direction.This displacement of the base body leads to a centering of the stripping bushing relative to the wire and consequently also to a reduction of the radial force transmitted to the base body. For example, with an ideal passage of the wire through the stripping bushing, essentially no radial force can be transmitted to the base body.

[0034] The first or second stop surface has a convex curvature. Convex means that the surface in question is curved outwards. For example, a cylinder, the lateral surface of a cylinder, or a sphere has a convex curvature. Due to the convex curvature, the base body is mounted in a tiltable position relative to the wire conveying direction. Therefore, a radial force acting on the base body can cause it to tilt, which in turn reduces the radial force. In summary, the friction-fit and tiltable mounting of the base body, combined with the forces acting on it, achieves self-centering of the wire relative to the stripping guide. In particular, the radial forces acting on the base body in the event of misalignment lead to this self-centering due to the inventive design of the stripping device.The stripping device is designed to minimize the radial forces acting on the base body, thus achieving self-centering. This self-centering is inherent in the design and therefore requires no manual adjustment. Furthermore, due to this self-centering, the stripping device is able to follow time-varying fluctuations and ensure consistent homogeneity of the coating material layer thickness. For example, the base body can follow any vibrations of the wire and / or any variable deflection of the wire. The base body can be adjusted relative to the...

[0035] The wire conveying direction may be tilted by an angle of up to 20°, in particular up to 10°. The first stop surface or the second stop surface may have a radius of curvature of 2 mm to 10 mm. In particular, the radius of curvature may be in a range between 4 mm and 8.5 mm.

[0036] In its intended state, the wire does not rest directly on the base body. Only a portion of the liquid coating material on the wetted wire comes into contact with the base body, thereby removing excess coating material. The base body is therefore suspended on the wire and the coating material. The coating thickness on the wire can, for example, range from 10 µm to 40 µm. The wire can be conveyed in the wire feed direction at speeds between 8 m / min and 200 m / min.

[0037] The first stop surface can be displaced relative to the second stop surface along a first direction, in particular vertically, for example within a range of 110 mm, particularly within a range of ±4.5 mm. The first stop surface can be displaced relative to the second stop surface by at least ±4.5 mm. The first stop surface can be displaced relative to the second stop surface along a second direction, in particular horizontally (i.e., laterally), for example within a range of ±15 mm, particularly within a range of ±4.5 mm. Optionally, in addition to the axial stop, the stop unit can have a stop in a direction normal to the wire conveying direction to limit the displacement of the base body. For example, in the case of a horizontal wire conveying direction, the lateral play of the base body can be between 2 mm and 3 mm, i.e.,The base body can be displaced laterally by up to 3 mm. Due to the influence of gravity and the resulting vertical deflection of the wire, in a horizontal wire conveying direction (as is the case with horizontal systems), compensating for vertical fluctuations is more critical than compensating for any other horizontal influences. Therefore, vertical displacement can exceed lateral displacement.

[0038] In addition to the axial and radial forces acting on the base body due to the stripped coating material, a weight force also acts on the base body due to its mass. In the case of a horizontal system (with a substantially horizontal wire feed direction), this weight force can act perpendicular to the wire feed direction. To minimize any potential influence of this weight force on the homogeneity of the coating thickness, it is advantageous for the base body to have the smallest possible mass. Furthermore, a small mass results in low inertia of the base body and therefore rapid self-centering, which can compensate for particularly rapid fluctuations. The weight of the nozzle can also cause a torque to act on the base body.For example, the axial force acting on the base body can compensate for this weight-related torque, preventing the base body from tilting undesirably perpendicular to the wire feed direction. The lower the mass of the base body, the lower this weight-related torque. For example, the base body can be designed to be as short as possible in the wire feed direction and as narrow as possible perpendicular to it. For example, the length of the base body in the wire feed direction can be between 5 mm and 40 mm. The height of the base body perpendicular to the wire feed direction can be, for example, between 5 mm and 20 mm. The width of the base body perpendicular to both the height and length can be, for example, between 10 mm and 20 mm. The base body can be made of a metal, for example, stainless steel.

[0039] Preferably, the base body can be made of or consist of titanium. Titanium has a lower density than stainless steel, which means that the base body can have a particularly low mass when using titanium. The base body can be made of aluminum or a plastic, such as Teflon. The base body can be made of a material that exhibits or ensures high resistance to organic wire enamel solvents as well as high dimensional stability. The base body can be manufactured by electrical discharge machining (EDM). The base body can, for example, have a mass of less than 10 g. Preferably, the mass of the base body is less than 5 g. In particular, the mass of the base body can be between 5 g and 7 g.

[0040] The stop unit can be a single piece or multi-part. For example, the stop unit can have one or more stop elements with which the base body can be frictionally connected. The first stop surface can, for example, lie section by section on one stop element and section by section on another stop element. Neither the wire nor the coating material comes into contact with the stop unit during intended use. In particular, the wire exits the stripping opening of the base body unimpeded. The stripping opening is not covered by the stop unit. The stop unit can, for example, have a further opening for the wire.

[0041] The coating material is liquid during wetting of the wire (for example, a bare wire or a wire already coated with coating material) and during wiping, and can therefore be dried and / or cured. The coating material can be, for example, a varnish, in particular a wire varnish. The wire varnish can, for example, contain polymers dissolved in a solvent, in particular an organic solvent. The coating material can be a non-Newtonian fluid. A dynamic viscosity of the coating material can, for example, be between 500 mPas (millipascal seconds) and 12,000 mPas.

[0042] The application unit according to the invention for applying at least one layer of the coating material to the wire comprises a wetting unit for applying the coating material, wherein the wetting unit has a wetting unit base body with a wetting passage for the wire. The application unit is configured to wet the wire with the coating material and to wipe off excess coating material in order to produce a homogeneous layer of coating material on the wire. For this purpose, the application unit has at least one wetting unit for applying the coating material. The wetting unit base body can be one-piece or multi-piece. In its intended state, a main axis of the wetting passage lies in the wire conveying direction, so that the wire is conveyed through the wetting passage.The wetting feedthrough can, for example, have a constant cross-section perpendicular to the wire feed direction. The wetting unit can be connected to and supplied with a reservoir or tank containing coating material. The wetting feedthrough can, for example, be flooded with liquid coating material. The wetting unit can wet the wire completely with coating material.

[0043] The application unit includes a stripping device according to the invention for removing excess coating material from the wire. The stripping device is arranged downstream of the wetting unit in the wire conveying direction. In its intended state, the wire passes through the wetting feedthrough and the stripping feedthrough. The main axis of the wetting feedthrough preferably coincides with the main axis of the stripping feedthrough, i.e., the main axis of the wetting feedthrough and the main axis of the stripping feedthrough can lie on a (common) straight line. The wetting feedthrough is typically significantly larger than the stripping feedthrough, which is why misalignments of the wire relative to a main axis of the wetting feedthrough are considerably less critical than misalignments of the wire relative to the main axis of the stripping feedthrough.While the wetting unit is only responsible for ensuring sufficient wetting of the wire, the homogeneity of the layer thickness of the coating material remaining on the wire depends significantly on the stripping device.

[0044] The problem according to the invention is also solved by a method for producing coated wires with an application unit according to the invention, comprising the steps:

[0045] - Conveying a wire in the wire conveying direction towards the application unit;

[0046] - Applying a layer of the coating material to the wire using the wetting unit;

[0047] - Removing excess coating material from the wire using the stripping device;

[0048] - Displacement and / or tilting of the base body by a force transmitted from the coating material to the base body, such that a principal axis of the wire coincides with a principal axis of the stripping feedthrough. The force transmitted to the wire, which is responsible for the displacement and / or tilting of the base body, is the radial force discussed above. In particular, due to the displacement and / or tilting of the base body caused by the radial force and enabled by the stripping device according to the invention, any misalignments of the wire relative to the principal axis of the stripping feedthrough can be easily, quickly, and without manual intervention compensated for.

[0049] The stripping fineness according to the invention can be used in both horizontal and vertical systems. While in horizontal systems it primarily compensates for effects due to the vertical deflection of the wire, in vertical systems it can mainly compensate for wire vibrations and any other movements transverse to the wire conveying direction.

[0050] For example, the first stop surface can be planar and the second stop surface can have a convex curvature. The planar first stop surface can, in particular, extend perpendicular to the wire conveying direction. The base body can have a semi-cylindrical section that forms the second stop surface with the convex curvature. The second stop surface of the base body therefore rests section by section along a straight line on the planar first stop surface of the stop unit. Along this straight line, the base body is frictionally connected to the stop unit.

[0051] The second contact surface can optionally be curved in two mutually orthogonal directions. For example, the base body can have a hemispherical section. The second contact surface of the base body therefore rests, at least section by section, on the planar first contact surface of the contact unit along a circle. Along this circle, the base body is (at least section by section) frictionally connected to the contact unit.

[0052] Alternatively, the second stop surface can be planar and the first stop surface can have a convex curvature.

[0053] The base body can include the stripping feedthrough with a wire entry opening and a wire exit opening, wherein a principal plane of the wire exit opening coincides with a principal extent plane of the first stop surface in the intended state. The stripping feedthrough can have a constant or a variable cross-section. The base body with the stripping feedthrough can be referred to as a coating nozzle. In particular, a section of the stripping feedthrough with the smallest cross-section is crucial for the resulting layer thickness of the coating material remaining on the wire. This section with the minimum cross-section is also referred to as the calibration zone. The calibration zone is typically located at a rear end of the coating nozzle when viewed in the wire feeding direction. In particular, the exact alignment of the wire relative to the calibration zone is crucial for the layer thickness.The calibration zone can be made of materials such as diamond, polycrystalline diamond (PCD), or cemented carbide (e.g., tungsten carbide). The base body can be made of stainless steel, tool steel, or titanium and coated with cemented carbide. For self-adjustment, the distance between the calibration zone and a contact area where the first stop surface rests against the second stop surface is relevant. Particularly precise wire passage through the calibration zone can be achieved, for example, by ensuring that the wire exit opening, in its intended state, lies at least partially within the main plane of extension of the (planar) first stop surface. For instance, the main plane of extension of the first stop surface can intersect the calibration zone.

[0054] For example, the base body can have a center of mass that, in its intended state, lies in a principal plane of extension of the first contact surface. In this case, there are no significant or no torques on the base body resulting solely from its weight. This design leads to a particularly stable process. The removal of excess coating material also results in a weight force of this excess material acting on the base body. The base body, including the removed coating material, can have a center of mass that may differ from the center of mass of the base body. To avoid mass-induced torques on the base body particularly effectively, the center of mass of the base body, including the excess coating material, can lie in the principal plane of extension of the first contact surface.The center of mass of the base body can be determined, for example, on a 3D model of the base body, based on which the base body can be manufactured. The material (or materials) of the base body and, optionally, the coating material can be defined in the 3D model. The center of mass of the base body, including any excess coating material, can thus be estimated or determined from the 3D model. A spherical cap-shaped volume of excess coating material can be assumed at the inlet opening of the base body, where the cap diameter at an interface with the base body can correspond to the inner diameter of the inlet opening.Any minor contributions to the overall resulting center of mass that may be induced by gravity due to coating material flowing downwards can optionally be neglected in this estimate, since the contribution of the coating material to the center of mass of the base body, including the excess coating material, is comparatively small. Any further minor influence due to the mass density of the coating material, depending on the material used and / or the temperature, can also be neglected.

[0055] Optionally, the stripping feedthrough can be conically tapered, at least in sections, in the wire conveying direction. For example, the stripping feedthrough can taper funnel-shaped from the inlet opening and transition into a region with a constant cross-section. Due to the conical tapering of the stripping feedthrough, a particularly high radial force can occur due to wire misalignment and stripped coating material. Since the radial force is particularly crucial for self-adjustment, this design of the stripping feedthrough is especially well-suited to counteract misalignments caused by simultaneous... The stripping feedthrough can have at least one plane of symmetry. The principal axis of the stripping feedthrough can preferably lie in the plane of symmetry. Preferably, the stripping feedthrough can have at least a second plane of symmetry that is perpendicular to the first plane of symmetry.This symmetrical design is particularly advantageous in connection with flat wires. For example, the stripping feedthrough can be rotationally symmetrical with respect to its main axis. This design is particularly advantageous with respect to round wires. Symmetrical designs of the stripping feedthroughs result in correspondingly symmetrical radial forces in the event of misalignment, and thus in particularly homogeneous and reproducible layer thicknesses.

[0056] Optionally, the cross-section of the stripping feedthrough can be constant in sections in the wire conveying direction. Particularly in the calibration zone, the cross-section can be constant to produce especially homogeneous layer thicknesses.

[0057] Preferably, the stop unit can have two stop elements, wherein the stop elements are spaced apart from each other transversely to the wire conveying direction. This makes it particularly easy to ensure that the stripping guide is not obscured by the stop unit.

[0058] Optionally, the base body can be at least two-part and comprise at least two components. The base body can, for example, be divided along a plane containing a principal axis of the stripping feedthrough. This allows for particularly simple manufacturing of the base body, especially its two components. For instance, the two components can be positively connected. Alternatively, the two components can be detachably connected using fasteners such as screws or clamps. This makes replacing a base body (for example, to select a different coating thickness) particularly easy. In the case of a one-piece base body, the wire typically needs to be cut to remove it from the stripping feedthrough. In the case of a two- or multi-part base body, the base body can be replaced without cutting the wire.Dividing the base body makes it particularly easy to manufacture the individual parts. For example, the two parts can be produced by electrical discharge machining (EDM). Especially in the case of a two- or multi-part base body, it is advantageous if the base body is essentially cuboid in shape to simplify the use of screws as fasteners.

[0059] Preferably, the stop unit is rotatably mounted about an axis normal to the wire feed direction. For example, the second stop surface can have a convex curvature in a first direction normal to the wire feed direction and no curvature in a second direction normal to the first direction. For example, the base body can have a semi-cylindrical section. Accordingly, the base body can roll and thus tilt along the convex curvature of the lateral surface of the semi-cylindrical section that forms the second stop surface. This allows tilting in a first direction normal to the wire feed direction (corresponding to the convex curvature). In other words, the base body has a first rotational degree of freedom.In the case of a substantially horizontal wire conveying direction, the base body can preferably be tilted at least vertically, since external influences can predominantly lead to vertical vibrations. Deflection of the wire due to a weight force acting on the wire is also naturally vertically oriented. Therefore, tiltability of the base body in the vertical direction is particularly advantageous. If the stop unit is tilted about an axis perpendicular to the...

[0060] Since the wire feed direction is rotatably mounted, the base body has a second rotational degree of freedom relative to the wire feed direction, which preferably does not coincide with the first rotational degree of freedom. For example, the axis of the stop unit can be normal to a main axis of the semi-cylindrical section.

[0061] Optionally, a wire can be provided and passed through the stripping feedthrough. The wire can be coated with coating material and fed through the stripping feedthrough to remove excess coating material.

[0062] In rare cases where the wire is heavily coated with excess coating material, adhesive forces can cause stripped coating material to transfer from the base body to the first and / or second stop surface. To prevent this, the base body may have a boundary designed to prevent the coating material from reaching the first and / or second stop surface. This boundary may have a collar and / or a bead. For example, the boundary may surround the wire entry opening. The boundary may be spaced perpendicular to the wire feed direction from the wire entry opening. The boundary may, for example, have an edge.

[0063] The application unit can optionally be arranged on or in a collection basin for the coating material, wherein the collection basin and the at least one application unit form a coating bank. The coating material stripped from the wire by the stripping device drips into the collection basin and can optionally be reused. For example, several application units can be arranged parallel to one another on or in a collection basin. A device for producing coated wires comprises an application unit according to the invention for applying at least one layer of a coating material and an oven for curing the applied layer, wherein the oven is arranged downstream of the application unit in the wire conveying direction. The oven is configured to heat the wire together with the coating material applied by the application unit in order to dry and cure the coating material.The temperature inside the oven can range, for example, between 300°C and 800°C, and particularly between 450°C and 700°C. Under normal operating conditions, the wire does not rest on the application unit or the oven. The wire may rest on the support roller and on another roller located downstream of the oven. This ensures that the wire does not rest on the substrate as long as liquid (i.e., not yet cured) coating material is present on the wire. Specifically, the wire does not rest on the substrate within the stripping guide. Only a portion of the liquid coating material on the wire comes into contact with the substrate, thereby stripping off excess coating material.

[0064] The device can have several coating stations arranged sequentially, i.e., in series, in the wire conveying direction. The entirety of the application units or coating stations can be referred to as the coating unit.

[0065] The invention will be explained in more detail below using figures, to which it is not limited. The figures show:

[0066] Fig. 1A a schematic view of a stripping device including a wire;

[0067] Fig. 1B shows a schematic view of two parallel stripping devices for parallel wires or wire coverings;

[0068] Fig. 2A a schematic view of the basic body from Figures 1A and 1B;

[0069] Fig. 2B is a schematic exploded view of the base body from Fig. 2A;

[0070] Fig. 3A-C schematically shows a side view of a stripping device with a wire in three different positions;

[0071] Fig. 4A schematically shows another embodiment of a basic body 4;

[0072] Fig. 4B shows a top view of the second part of the base body from Figure 4A;

[0073] Fig. 5 shows another embodiment of a basic body;

[0074] Fig. 6 shows another embodiment of a basic body;

[0075] Fig. 7 shows a scraping device 1 with a further embodiment of a stop unit;

[0076] Fig. 8A, 8B and 8C show a paint bank with several parallel application units;

[0077] Fig. 9A schematically shows another embodiment of a basic body with a second stop surface curved in two directions;

[0078] Fig. 9B is a schematic view of a stripping device with the base body from Fig. 9A;

[0079] Fig. 10A schematically shows another embodiment of a basic body with a second stop surface curved in two directions;

[0080] Fig. 10B a schematic sectional view of a stripping device with the base body from Fig. 10A; Fig. 11A schematically another embodiment of a stripping device with a base body; and

[0081] Fig. 11B shows a schematic view of the stripping device from Fig. 11A.

[0082] Fig. 1A schematically shows a stripping device 1 for stripping excess coating material 2 from a wire 3 wetted with coating material, comprising a base body 4 with a stripping passage 5 (see Fig. 2A) for the wire 3. In the intended state (and also shown in this embodiment), the wire 3 is passed through the stripping passage 5 and conveyed in a wire conveying direction 6. A stop unit 7 is arranged in the wire conveying direction 6 after the base body 4. The stop unit 7 has a first stop surface 8, which, in the intended state, faces the base body 4. The base body 4 has a second stop surface 9 (see Fig. 2A), which, in the intended state (and shown here), faces the first stop surface 8.The first stop surface 8 is, at least partially, frictionally connected to the second stop surface 9 when used as intended. The base body 4 is mounted so as to be displaceable perpendicular to the wire conveying direction 6. In this embodiment, the wire conveying direction 6 is horizontally oriented (as is the case with horizontal systems). The first stop surface 8 or the second stop surface 9 has a convex curvature 10. In this embodiment, the first stop surface 8 is planar and the second stop surface 9 has the convex curvature 10. Due to the convex curvature 10 of the second stop surface 9 and the frictional connection of the first stop surface 8 with the second stop surface 9, the base body 4 can be displaced and tilted vertically, at least vertically, in order to compensate for any misalignment of the wire 3 relative to the stripping guide 5.

[0083] In this embodiment, wire 3 is provided and passed through the stripping feedthrough 5. In this embodiment, wire 3 is a flat wire with a substantially rectangular cross-section. Alternatively, the wire can be a round wire with a round, in particular circular, cross-section.

[0084] The stop unit 7 has two stop elements 7A, wherein the stop elements 7A are spaced apart from each other transversely to the wire conveying direction 6, in this example normal to the wire conveying direction 6.

[0085] Fig. 1B shows two stripping devices 1, which are aligned parallel to each other with respect to the wire conveying direction 6, in order to process parallel wires 3 or wire covers. The stop unit 7 has stop elements 7A arranged perpendicular to the wire conveying direction 6, which form a comb.

[0086] Fig. 2A shows a schematic view of the base body 4 from Figures 1A and 1B. In this embodiment, the base body 3 is divided into two parts: a first part 11 and a second part 12 (i.e., two parts 11 and 12) which are detachably connected to each other by means of screws 13. The first part 11 has a positive locking element 14 that engages positively with a recess 15 of the second part 12. This positive locking mechanism makes it particularly easy to prevent lateral displacement of the first part 11 relative to the second part 12 (i.e., perpendicular to a principal axis of the screws 13).

[0087] The base body 3 has a center of mass. In its intended state, the center of mass lies in a principal plane of extension of the (planar) first stop surface 8 (see Fig. 1). To achieve this, in this embodiment, the second stop surface 9 is formed by two convex sections 9A, which are offset from a wire exit opening 16 of the base body 4 in the opposite direction to the wire conveying direction 6 (cf. Fig. 1). The two convex sections (or surfaces) 9A lie on an (imaginary) cylindrical surface. The center of mass of the base body 4 also lies on this cylindrical surface. The two convex sections 9A each rest on one of the stop elements 7A. In this embodiment, the planar first stop surface 8 is formed by two planar sections 8A of the two stop elements 7A (see Fig. 1A and Fig. 1B). Each convex section 9A interacts with a planar section 8A.

[0088] Fig. 2B shows an exploded view of the base body 4 from Fig. 2A. The stripping feedthrough 5 has a wire inlet opening 17 and a wire outlet opening 16. The cross-section of the wire inlet opening 17 is larger than the cross-section of the wire outlet opening 16. The stripping feedthrough 5 tapers conically in sections in the wire conveying direction 6 (see Fig. 1A). In this embodiment, the stripping feedthrough 5 tapers in a funnel shape (and is therefore conical) starting from the wire inlet opening 17. The cross-section of the stripping feedthrough 5 in the wire conveying direction 6 is constant in sections. At one end facing the wire outlet opening 16, the stripping feedthrough 5 has a calibration zone 18 in which the cross-section of the stripping feedthrough 5 is constant.

[0089] Fig. 3A schematically shows a side view of a stripping device 1 with a wire 3 in a first position 19. The stripping device 1 is arranged on a multi-part holder 20. Due to an axial force transmitted to the base body 4 by the stripped excess coating material 2 (acting in the direction of the wire feed 6), the base body 4 is frictionally connected to the stop unit 7. The convex curvature 10 of the second stop surface 9 and the planar first stop surface 8 allow the base body 4 to be vertically displaceable and tiltable. In this case, the wire 3 is ideally horizontally aligned and passes centrally through the stripping opening 5 (see Figs. 2A and 2B). Due to the central opening, no effective radial forces (normal to the wire feed 6) act on the base body 4.

[0090] For example, if external influences cause the wire 3 to become misaligned compared to the stripping guide 5, a radial force is transferred to the base body 4 by the stripping of the excess coating material 2. Due to the sliding and tilting mounting of the base body 4 relative to the stop unit 3, the base body can react accordingly to the radial force.

[0091] Fig. 3B schematically shows a side view of the stripping device 1 from Fig. 3A in a second position 21. In this example, the wire 3 is vertically tilted and displaced compared to the first position 19 from Fig. 3B. The base body 4 is accordingly shifted and tilted vertically upwards, so that a principal axis of the wire 3 coincides with a principal axis of the stripping feedthrough 5, and consequently a homogeneous layer thickness of wetting material 2 is achieved.

[0092] Similarly, Fig. 3C schematically shows a side view of the stripping device 1 from Figures 3A and 3B in a third position 22. The wire 3 is again vertically displaced and tilted compared to the representations in Figures 3A and 3B. The base body 4 is displaced and tilted accordingly.

[0093] Fig. 4A schematically shows another embodiment of a base body 4 (similar to that in Fig. 2A). The base body 4 is in two parts and comprises the first part 11 and the second part 12. In this embodiment, in contrast to the embodiment according to Fig. 2A, no positive locking is provided by means of a positive locking element. The first part 11 and the second part 12 are connected to each other by means of dowel pins in this embodiment.

[0094] Fig. 4B shows a top view of the second part 12 of the base body 4 from Fig. 4A. The stripping feedthrough 5 is conically tapered starting from the wire entry opening 17. In the calibration zone 18, the cross-section of the stripping feedthrough 5 is constant.

[0095] Fig. 5 shows another embodiment of the base body 4. In this embodiment, the (convex) second stop surface 9 is not offset from the wire exit opening 16 of the base body 4 in the opposite direction to the wire conveying direction 6. As a result, a principal plane of the wire exit opening 16 coincides with the principal plane of extension of the (planar) first stop surface 8 in the intended state. According to this exemplary embodiment, the convex second stop surface 9 lies on a (continuous) semi-cylindrical section 23.

[0096] Fig. 6 schematically shows another embodiment of the base body 4. In this embodiment, the (convex) second stop surface 9 is formed by two convex sections 9A and is arranged offset from the wire exit opening 16 of the base body 4 in the opposite direction to the wire conveying direction 6. According to this exemplary embodiment, the convex sections 9A each lie on a cylindrical section 24.

[0097] Fig. 7 schematically shows a stripping device 1 with a further embodiment of a stop unit 7. In this embodiment, the stop unit 7 is rotatably mounted about an axis 29 perpendicular to the wire conveying direction 6. This gives the base body 4 two rotational degrees of freedom, one rotational degree of freedom resulting from the convex curvature 10 and the friction-fit, displaceable, and tiltable mounting of the base body 4 on the stop unit 7, and the second rotational degree of freedom resulting from the rotatable mounting of the stop unit 7 about the axis 29. The rotatable mounting of the stop unit 7 allows for compensation of both vertical and horizontal tilting of the wire 3. Due to the rotatable mounting about the axis 29, the two stop elements 7 are approximately in the shape of a tuning fork.

[0098] Figures 8A, 8B and 8C schematically show a coating bench 31 with several parallel application units 25 and a basin 30 for wiped-off excess coating material 2. Several parallel wires 3 or wire covers are provided, which are coated parallel to each other with coating material 2.

[0099] Each application unit 25 for applying at least one layer of the coating material 2 to the wire 3 has a wetting unit 26 for applying the coating material 2. The wetting unit 26 has a wetting unit base body 27 with a wetting feedthrough 28 for the wire 3. Furthermore, each application unit 25 has a wiping device 1 for wiping excess coating material 2 from the wire 3, wherein the wire 3, in its intended (and shown here) state, is passed through the wetting feedthrough 28 and the wiping feedthrough 5.

[0100] While the wetting units 26 are essentially parallel to each other in the wire conveying direction 6, adjacent stripping devices 1 are each offset from each other in the wire conveying direction. This forms two offset combs on stop elements 7A. The offset arrangement of these combs makes the stripping units 1 more accessible and easier to maintain. Alternatively, the stripping devices 1 can be arranged parallel to each other.

[0101] A device for producing coated wires has an application unit 25 for applying at least one layer of the coating material 2 and an oven (not shown) for solidifying the applied layer, wherein the oven is arranged downstream of the application unit 25 in the wire conveying direction 6.

[0102] A process for producing coated wires 3 with the application unit 25 comprises the following steps:

[0103] - Conveying the wire 3 in the wire conveying direction 6 towards the application unit 25 ;

[0104] - Applying a layer of the coating material 2 to the wire 3 using the wetting unit 26;

[0105] - Stripping excess coating material 2 from the wire 3 using the stripping device 1 ;

[0106] - Displacement and / or tilting of the base body 4 by a force transmitted from the coating material 2 to the base body 4 (i.e. radial force) such that a principal axis of the wire 3 coincides with a principal axis of the stripping feedthrough 5 (see, for example, Figures 3A-C).

[0107] Fig. 9A schematically shows another embodiment of the base body 4 with a second stop surface 9 curved in two directions. In this embodiment, the second stop surface 9 is curved in two mutually orthogonal directions. Due to this curvature, the base body is mounted to tilt in any direction normal to the wire conveying direction 6. In comparison, for example, the base body 4 from Fig. 1A is mounted to tilt in only one direction. The base body 4 is designed in two parts and has a first part 11 and a second part 12, which are fastened to each other by means of screws 13.

[0108] The base body 4 can interact with a planar first stop surface 8 (similar to how it is shown, for example, in Fig. 1A).

[0109] Fig. 9B shows a schematic view of a stripping device 1 with the base body from Fig. 9A and a stop unit 7. In this embodiment, the stop unit 7 has a concave recess 32. The first stop surface 8 therefore has a concave curvature. The concave curvature of the first stop surface 8 interacts with the convex curvature of the second stop surface 9, so that the base body 4 is supported on or in the stop unit by means of the axial force transmitted to the base body 4 and is restricted in its translational movement.

[0110] The excess coating material 2 forms a roughly spherical volume 33 at the wire inlet opening 17 of the base body. Due to gravity, the excess coating material 2 flows downwards perpendicular to the wire conveying direction 6 and ultimately drips off the base body 4.

[0111] Fig. 10A schematically shows another embodiment of a base body 3 with a second stop surface 9 curved in two directions. Compared to the embodiment according to Fig. 9a, this embodiment has a circular recess 34. This circular recess 34 interacts with a corresponding counter element 35 of the stop unit 7, as can be seen in the schematic sectional view from Fig. 10. The counter element 35 (similar to the embodiment according to Fig. 9B) has a concave curvature and engages in the annular recess to restrict the translational freedom of movement of the base body 4.

[0112] Figures 11A and 11B schematically show another embodiment of a stripping device 1 with a base body 4 and a stop unit 7. In this embodiment, the base body 4 has two cylindrical bearing elements 36 on its sides. The cylindrical bearing elements 36 have the first stop surface 9, which is formed by two convex sections 9A (similar to the embodiment according to Fig. 2A). The stop unit 7 has two guides 37. The two cylindrical bearing elements 36 each engage in a guide 37. The guides 37 have the first stop surface 8, which is formed by two planar sections 8A. The two cylindrical bearing elements 36 can each roll on a planar section 8A and be displaced against a planar section 8A. The base body 4 is therefore mounted to be tiltable and displaceable perpendicular to the wire conveying direction 6.

Claims

Patent claims:

1. Stripping device (1) for stripping excess coating material (2) from a wire (4) wetted with coating material (2), comprising: - a base body (4) with a stripping passage (5) for the wire (3), wherein the wire (3) is passed through the stripping passage (5) in the intended state and is conveyed in a wire conveying direction (6); and - a stop unit (7) arranged in the wire conveying direction (6) after the base body (4); wherein the stop unit (7) has a first stop surface (8), wherein the first stop surface (8) faces the base body (4) in the intended state, wherein the base body (4) has a second stop surface (9), wherein the second stop surface (9) faces the first stop surface (8) in the intended state, characterized in that the first stop surface (8) is at least partially frictionally connected to the second stop surface (9) when used as intended, wherein the base body (4) is mounted to be displaceable normal to the wire conveying direction (6), wherein the first stop surface (8) or the second stop surface (9) has a convex curvature (10).

2. Scraper device (1) according to claim 1, characterized in that the first stop surface (8) is planar and the second stop surface (9) has the convex curvature (10).

3. Stripping device (1) according to claim 2, characterized in that the base body (4) has the stripping passage (5) with a wire entry opening (17) and a wire exit opening (16), wherein a main plane of the wire exit opening (16) coincides with a main extension plane of the first stop surface (8) in the intended state.

4. Scraper device (1) according to claim 2, characterized in that the base body (4) has a center of mass, wherein the center of mass in the intended state lies in a principal extension plane of the first stop surface (8).

5. Stripping device (1) according to one of the preceding claims, characterized in that the stripping passage (5) is at least partially conically tapered in the wire conveying direction (6).

6. Stripping device (1) according to one of the preceding claims, characterized in that a cross-section of the stripping passage (5) in the wire conveying direction (6) is constant section by section.

7. Stripping device (1) according to one of the preceding claims, characterized in that the stop unit (7) has two stop elements (7), wherein the stop elements (7) are spaced apart from each other transversely to the wire conveying direction (6).

8. Scraper device (1) according to one of the preceding claims, characterized in that the base body (4) has at least two parts (11, 12).

9. Stripping device (1) according to one of the preceding claims, characterized in that the stop unit (7) is rotatably mounted about an axis (29) normal to the wire conveying direction (6).

10. Stripping device (1) according to one of the preceding claims, characterized in that a wire (2) is provided and is passed through the stripping passage (5).

11. Application unit (25) comprising for applying at least one layer of a coating material (2) to a wire (3): - a wetting unit (26) for applying the coating material (2), wherein the wetting unit (26) has a wetting unit base body (27) with a wetting feedthrough (28) for the wire (3); characterized by - a stripping device (1) according to one of the preceding claims for stripping excess coating material (2) from the wire (3) , wherein the wire (3) is passed through the wetting passage (28) and the stripping passage (5) in the intended state.

12. Device for the production of coated wires (3) characterized by an application unit (25) according to claim 11 for applying at least one layer of a coating material (2) and an oven for solidifying the applied layer, wherein the oven is arranged downstream of the application unit (25) in the wire conveying direction (6).

13. Method for producing coated wires (3) with an application unit (25) according to claim 11 comprising the steps: - Conveying a wire (3) in a wire conveying direction (6) towards the application unit (25) ; - Applying a layer of the coating material (2) to the wire (3) using the wetting unit (25) ; - Stripping excess coating material (2) from the wire (3) using the stripping device (1) ; - Displacement and / or tilting of the base body (4) by a force transmitted from the coating material (2) to the base body (4), such that a principal axis of the wire (3) coincides with a principal axis of the stripping feedthrough (5).

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