WALL COMPONENT

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of German Application No. 102024122645.5, filed on Aug. 8, 2024. The entire disclosure of the application referenced above is incorporated herein by reference.

The invention relates to a wall component of a work container for a vibratory grinding system, said wall component comprising an outer jacket surface, which extends about a center axis, and an inner wall that is provided with a profiling that has a microstructure in the form of parallel micro elevations and micro depressions. Such a wall component can be used together with a turntable, which forms a base of the work container, in vibratory grinding processes of any kind.

The inner wall of such work containers should not be ideally smooth since the moving components then tend to stick. An inner wall provided with microstructures can prevent the adhesion, in particular if the structures in the form of groove-like elevations and depressions are smaller than characteristic dimensions of the components. However, surfaces that are uniformly structured over the entire container wall can behave like a smooth wall in terms of flow dynamics in certain cases. Components are then moved in the direction of the inner wall by the relative movement during the vibration machining or the centrifugal machining and then follow said inner wall in laminar flow patterns parallel to the container wall. A cross-mixing, i.e., for example, in a radial direction, does not take place.

It has therefore already been suggested to provide deflectors at the inner wall that impose a radial movement component on the components moved parallel to the container wall. The components are hereby deflected in round containers towards the center. The laminar flow pattern is broken.

However, when machining small components (e.g. size range in all dimensions up to approximately 50 mm), in particular flat or compact components such as small plates, bolts, rings, annular valves, etc., uneven machining results can occur in vibratory grinding processes if the components do not have substantially the same dwell time in all areas of the machining volume. This can in principle occur in all vibratory grinding processes such as vibration processes or in centrifugal systems with grinding bodies or also in part-against-part machining in preferably round containers, but also in square containers.

Uneven dwell time distributions of the components in such processes occur if, for example, components are fixedly held at the walls of the containers by adhesion and are thus no longer permanently circulated together with the other parts.

Furthermore, components in flow dead zones such as vortices behind flow deflectors or entrainers can be stopped. In these flow dead zones, the parts are only moved minimally against one another or against the grinding bodies, whereby the effective processing time of these parts is significantly reduced.

Components and grinding bodies (with/without process fluid such as water) behave very similarly to pure fluid flows. With regard to the use of flow deflectors, this means that a radial component is imposed on the flow close to the wall by the deflector towards the center of the container, whereby dead zones can, however, typically arise in front of and behind the deflector due to vortex formation in the dust region of the deflector or in the flow shadow of the deflector. In these dead zones, adhesion can additionally also occur with smooth structures at the wall or at the deflector.

It is therefore the object of the present invention to provide a wall component of the kind described above, with which a work container can be created with which a uniform machining of the components can be achieved in a vibratory grinding process without the formation of flow shadows.

This object is satisfied by the features of claim 1 and in particular in that a macrostructure in the form of macro elevations is superposed on the microstructure present at the inner wall. Here, the macrostructure serves as a flow deflector to impose a radial component on the components within the container, whereas the microstructures serve to counteract a laminar flow parallel to the container wall so that the components do not adhere to the inner wall for machining or can be safely carried along by the flowing process fluid (=machining fluid, e.g. water with/without additives, components and/or grinding bodies) and can thus be returned to the uniform machining again. In this respect (unlike in microtechnology), a microstructure is not necessarily understood as a dimension that can also be meaningfully specified in micrometers, but as a structure with dimensions in the range from mm to cm.

Advantageous embodiments of the invention are described in the description, in the drawing and in the dependent claims.

According to a first advantageous embodiment, the macro elevations can extend at least for the most part parallel to the micro elevations. In this embodiment, the macro elevations form wave crests of the inner wall that extend in a direction parallel to the center axis and parallel to the micro elevations. The surface of the macro elevations is therefore likewise provided with micro elevations that in particular do not differ from the micro elevations outside the macro elevations. In this embodiment, the micro elevations and micro depressions in the region of the macro elevations thus have the same cross-sectional shape and surface contour as outside the macro elevations.

According to a further advantageous embodiment, the macro elevations can, in a sectional plane extending perpendicular to the center axis, have an outer contour that is symmetrical to a radial beam and that is in particular of a circular arc shape. The advantage is hereby achieved that the components sliding along the inner wall during vibratory grinding do not form any flow dead zones due to the symmetrical design of the macro elevations, but rather flow uniformly along the convex elevation formed by the macro elevations in the region of the inner wall, wherein a radial velocity component is nevertheless imposed on the components. In any case, the size of the flow dead zones is at least significantly reduced, e.g. to the size range of a minimum component dimension.

According to a further advantageous embodiment, the micro elevations and micro depressions can, in a sectional plane extending perpendicular to the center axis, have a contour that is symmetrical to a radial beam and that is in particular of a circular arc shape. The inner wall can hereby be given a groove structure that contains wave crests and wave troughs whose curvature extends uniformly and without discontinuities. However, it is also possible to impose other cross-sectional shapes on the microstructure, for example, elevations with a trapezoidal or rectangular cross-sectional shape.

According to a further advantageous embodiment, two macro elevations can be disposed diametrically opposite one another in each case. Particularly good results were achieved with such an embodiment in initial tests.

According to a further advantageous embodiment, all the elevations, i.e. those of the microstructure and those of the macrostructure, can be part of a coating composed of plastic, for example a polyurethane coating.

According to a further aspect, the present invention relates to a work container for a vibratory grinding system, said work container comprising a wall component of the kind described above and a base. The base can be fixedly connected to the wall component or can also configured as a turntable to set the components inside the container into rotation.

According to a further aspect, the present invention relates to a method for the vibratory grinding of workpieces in a work container of the kind described above, wherein the dimensioning of the microstructure and the macrostructure is selected in dependence on a minimum dimension Dmin of the components to be machined. In this respect, the minimum dimension Dmin of the components is understood as the smallest characteristic dimension of the components. In the case of cylindrical components, this is, for example, the diameter of the components. For cuboid components, this is, for example, the smallest extent along all three spatial axes.

With the method according to the invention, the geometry of the micro depressions and the macro elevations is selected such that the micro depressions have a circular arc-shaped contour that is symmetrical to a radial beam and that has a radius R_Micro, while the macro elevations have a circular arc-shaped contour that is symmetrical to a radial beam and that has a radius R_Macro. If the geometries are further selected so that R_Macro is greater than R_Micro, R_Micro is between 0.5 and 2 times D_min, and/or R_Macro is between 3 and 50 times D_min, the components can then be prevented from sliding in a laminar manner along the inner wall, on the one hand, and from getting stuck in the depressions, on the other hand. Furthermore, it can be advantageous if R_Macro is at least ten times, in particular at least twenty times, in particular at least 30, 40 or 50 times greater than R_Micro, in order to achieve an advantageous flow behavior in the vibratory grinding process.

The present invention will be described in the following purely by way of example with reference to an advantageous embodiment and to the enclosed drawings. There are shown:

FIG. 1 a section through a work container with a wall component and a turntable as the base;

FIG. 2 a sectioned plan view of the work container of FIG. 1; and

FIG. 3 a section through a macrostructure of the inner wall.

FIG. 1 shows a work container 10 for a vibratory grinding system, said work container 10 being composed of a wall component 12 and a base that is configured as a turntable 14 in the embodiment example shown. In the embodiment example shown, the wall component 12 is configured as a hollow cylinder having a center axis M that simultaneously forms an axis of rotation of the turntable 14. The wall component 12 has a circular cylindrical outer jacket surface 16 and an inner wall 18 that is formed by a coating 20, for example a polyurethane coating 20, that is applied to a steel jacket or plastic jacket 22 forming the outer jacket surface 16.

The turntable 14 forming the base of the work container 10 is likewise provided with a coating 24 at its inner side, wherein drainage openings 26 extend through the coating 24 and the base 14. Furthermore, the coating 24 has radially extending rib-shaped elevations 28 that serve as entrainers.

As the Figures illustrate, the inner wall 18 of the wall component 12 is provided with a profiling. On the one hand, said profiling consists of a microstructure 30 in the form of a plurality of parallel micro elevations and micro depressions that are located along the entire inner circumference in the axial direction at the inner wall 18. The microstructure 30 extends in the axial direction, i.e. parallel to the center axis M, from the upper side of the wall component 12 up to a region in which the inner wall 18 begins to taper slightly in the direction of the center axis M.

Furthermore, a macrostructure in the form of macro elevations 32 is superposed on the microstructure 30 at the inner wall 18. Said macro elevations 32 extend for the most part parallel to the micro elevations 30, but can be chamfered at their upper and/or lower axial end so that slanted surfaces 34 and 36 inclined towards one another result.

FIG. 3 shows a section through the coating 20 of the work container 10 in the region of a macro elevation 32. As can be seen, the surface of the macro elevations 32 facing into the container interior is provided with the same micro elevations 30 as the rest of the inner wall. The micro elevations 30—and correspondingly also the micro depressions formed by the micro elevations—have the same cross-sectional shape in the region of the macro elevations 32 as outside the macro elevations 32, namely a circular arc-shaped contour that is symmetrical to a radial beam 38 (FIG. 2) in a sectional plane perpendicular to the center axis M. On average, the micro elevations 30 thus have the shape of a periodic wave, as is characteristic, for example, of sine waves or waveforms composed of circular segments, wherein the circular segments are typically smaller than semicircles.

The macro elevations 32 likewise have, in a sectional plane extending perpendicular to the center axis M, an outer contour that is symmetrical to a radial beam 38 and that of a circular arc shape, wherein the radius of the circular arc has its origin outside the container interior. The elevations and depressions of the microstructure each have a radius R_Micro that is the same for the elevations and for the depressions in order to form the sinusoidal wave structure of the microstructure 30. In this respect, R_Micro can, for example, be 4 to 5 mm and R_Macro can, for example, be 80 to 150 mm.

Finally, FIG. 2 illustrates that, in the embodiment shown, two macro elevations 32 are disposed diametrically opposite one another in each case, i.e., in the embodiment example shown, a total of four macro elevations 32 are provided that are superposed on the micro elevations 30.