EP3681675A1

EP3681675A1 - Abrasive article

Info

Publication number: EP3681675A1
Application number: EP18758604.5A
Authority: EP
Inventors: Josef Breitenmoser
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-09-13
Filing date: 2018-08-21
Publication date: 2020-07-22
Also published as: CN111093900B; US11697186B2; DE102017216175A1; CN111093900A; US20200180107A1; WO2019052787A1

Abstract

The invention relates to an abrasive article (10a,10b,10c,10d), in particular a coated abrasive disc, comprising a plurality of holes (12a,12b,12c,12d) which are arranged in a hole pattern (14a,14b,14c,14d), wherein the density of holes decreases from an inner region (18a,18b,18c,18d) of the hole pattern (14a,14b,14c,14d) to an outer region (20a,20b,20c,20d) of the hole pattern (14a,14b,14c,14d). The invention is characterized in that at least one hole (12a,12b,12c,12d) in the hole pattern (14a,14b,14c,14d) is designed as an elongated hole (38a,38b,38c,38d).

Description

description

title

abrasive article

The invention relates to an abrasive article, in particular a coated abrasive disc, having a plurality of holes arranged in a hole pattern, wherein a hole density decreases from an inner region of the hole pattern to an outer region of the hole pattern.

State of the art

Abrasive articles, in particular coated grinding wheels, having a plurality of holes arranged in a pattern of holes are known from the prior art, for example from EP 0781629 B1. Such grinding wheels are intended for attachment to a sanding plate of a sanding device, in particular an orbital sanding device. Such grinding devices typically have a dust extraction system, by means of which during a grinding process material removed from a working surface, in particular grinding dust, is sucked out through the holes of the grinding wheel.

It is further known from US Pat. No. 5,989,112 and DE 202007004949 U1 to select a shape of holes of the hole pattern in such a way that it is possible to use the abrasive article with a multiplicity of different sanding plates, which in particular have a differing number of holes and / or slightly different hole patterns. In particular, at least some holes of the abrasive article to an elongated shape. From WO 2015/002865 an abrasive article with a plurality of holes is known, which are arranged in a hole pattern, wherein the hole pattern has a first inner area with at least one hole and a second outer area with at least one hole, the second area concentrically around Further, from a size of the holes and a number of the holes, a hole density is defined for the respective area and the hole density of the first, inner area is smaller than the hole density of the second, outer area ,

There is a continuing need in the abrasives industry to further increase material removal in the processing of processing surfaces, while preventing clogging of the abrasive article with abraded material, particularly grinding dust. In particular, clogging of the abrasive article surface is to be avoided so as not to reduce the effectiveness of the abrasive article and, further, to counteract an increase in the likelihood of scratch damage caused by pieces of material deposited on the surface of the abrasive article.

Disclosure of the invention

The invention is based on an abrasive article, in particular a coated grinding wheel, with a plurality of holes for sucking off grinding dust from a processing surface during a grinding process on the processing surface. The plurality of holes are arranged in a hole pattern, whereby a hole density decreases from an inner area of the hole pattern to an outer area of the hole pattern. According to the invention, at least one hole in the hole pattern is formed as a slot.

In particular, the abrasive article is a coated abrasive article, in one embodiment a coated abrasive wheel The abrasive article comprises a backing having at least one layer, particularly of paper, paperboard, vulcanized fiber, foam, a plastic, a textile structures, in particular a woven, knitted, knitted, braided, non-woven, or a combination of these materials, in particular paper and tissue, in one or more layers. The, in particular flexible, backing serves as a carrier layer and gives the abrasive article specific properties in terms of adhesion, elongation, tear and tensile strength, flexibility and stability. Abrasive grains are applied and fixed on the carrier layer. By way of example, in the case of a coated abrasive article, abrasive grains adhere to the, in particular flexible, backing due to a base binder. With the base binder, the abrasive grains are prefixed in particular in the desired position and distribution on the substrate. Suitable base binders for applying abrasive grains to a prior art backing are well known to those skilled in the art. As a basic binder in particular synthetic resins, such as

Example, phenolic resin, epoxy resin, urea resin, melamine resin, polyester resin, or the like into consideration. In addition to the base binder, the abrasive article may comprise at least one capping agent, for example a plurality of top coaters. The coat binder (s) are applied in particular layer by layer to the base binder and the abrasive grains. Here, the one or more deckbinders connects the

Abrasive grains firmly together and firmly with the substrate. The person skilled in the art is well aware of suitable prior art cap binders. Synthetic resins, for example phenolic resin, epoxy resin, urea resin, melamine resin, polyester resin, are particularly suitable as capping agents. In addition, further binders and / or additives may be provided to impart specific properties to the abrasive article. Such binders and / or additives are familiar to the person skilled in the art.

Alternative abrasive articles, such as bonded abrasive articles C.bonded abrasives "), are also conceivable. [0003] Bonded abrasive articles are, in particular, synthetic resin-bonded cutting and grinding disks which are familiar to the person skilled in the art as well as fillers, powder resin and liquid resin, which are then pressed into cutting and grinding discs in various thicknesses and diameters.

The abrasive article can be present in different, in principle arbitrary, Konfektionsformen, for example as a grinding wheel or abrasive belt, as a sheet, sheet, roll or strip. Typically, the shape of the abrasive article is dictated by an intended grinding process (for example, for use in a belt grinder). In one embodiment, the abrasive article is realized as a grinding wheel. A "grinding wheel" is to be understood in particular as a unit of the abrasive article which forms the tool of a grinding device (in particular a grinding machine), in particular a rotary grinder or an eccentric grinder or orbital sander, and during operation of such a machine directly with a working surface of a workpiece for ablation The grinding wheel may be made substantially planar, ie flat, In principle, any size of grinding wheel is possible, including typical standard sizes of grinding wheels, for example in the range of 5 cm to 50 cm realized a circular grinding wheel with a diameter of 15 cm.The technical teaching underlying the present invention is applicable to any sizes and geometries of abrasive articles, in particular of grinding wheels, a Schleifschei Be is particularly intended to be reversibly releasably connected to a sanding plate of a grinder. In this context, a "sanding pad" is to be understood as meaning, in particular, a unit of a sanding device, for example an eccentric sanding device or an orbital sanding device, which is intended to receive an abrasive article, in particular a grinding wheel When the grinding device is switched on, the sanding plate together with the abrasive article attached thereto, in particular with the grinding wheel attached to it, is driven, in particular moved, by the grinding device.

The size and shape of the abrasive article determines the maximum surface area of the abrasive article available as the sanding surface (ie, without deduction of area fractions resulting from holes in the abrasive article). For example, a circular grinding wheel with a diameter of 15 cm has a maximum surface area of 176.7 cm ² available as the grinding surface. Each hole introduced into the abrasive article reduces this area available as the abrasive surface by the area occupied by the hole. The abrasive article has a plurality of holes, ie, perforations or apertures, which serve to extract material generated on a processing surface during the grinding process, in particular grinding dust or other material, by means of a suction device of the grinding device. In this case, a "hole" is understood to mean an opening or recess in the abrasive article which passes completely through the abrasive article, ie which extends in particular through the underlay and the coating located thereon in the direction substantially perpendicular to the abrasive article surface. In this document, any kind of hole is to be understood regardless of a geometrical realization. In particular, the term "hole" thus encompasses both a circular hole and a substantially round hole. A "substantially round hole" may be a polygonal hole, in particular a triangular, quadrangular, in particular rectangular or square, star-shaped, polygonal, in particular Isogones, or partially angular and partially curved hole be realized. Furthermore, the shape of the hole may otherwise be selected from regular or irregular, in particular polygonal, shapes. The envelope of the geometric figure approaches a circle. In particular, a circular and a substantially round hole can be described by at least one radius n_. A circular hole or hole may have a radius n_ ranging from about 0.25% to about 5% of the longest dimension of the abrasive article, particularly in the range of 0.5% to 1.5% of the longest Dimension of the abrasive article. In the exemplary embodiment of a grinding wheel, the diameter of the grinding wheel represents the longest dimension of the abrasive article. In particular, a substantially round hole may have a radius ri_ which in the

Range of 0.375 mm to about 7.5 mm, in particular in the range of 0.75 mm to 2.25 mm. In one embodiment, a substantially round hole or hole has a radius n_ of 1.0 mm, 1.2 mm or 1.5 mm.

According to the invention, at least one hole in the hole pattern is formed as a slot. An elongated hole has an elongated or elongated shape in relation to a substantially round hole or a circular hole. In particular, a slot can be described by at least one radius n_i_ and a length LL. Further, a slot may define an axis passing through the Direction of elongation (ie in the extension direction of the length LL) is given. A slot may have a length LL ranging from about 2% to about 13% of the longest dimension of the abrasive article, particularly in the range of 2.5% to 6.5%. In particular, a slot may have a length LL which is in the range of 3 mm to about 20 mm, in particular in the range of 4 mm to 10 mm. In one embodiment, a slot has a length LL of 4 mm, 5 mm or 6 mm. A slot may have a radius H_L ranging from about 0.25% to about 5% of the longest dimension of the abrasive article, particularly in the range of 0.5% to 1.5%. In particular, a long hole may have a radius H_L which is in the range of 0.375 mm to about 7.5 mm, in particular in the range of 0.75 mm to 2.25 mm. In one embodiment, a slot has a radius H_L of 1.0 mm, 1.2 mm or 1.5 mm.

Furthermore, a slot can in principle also have a shape that is selected from polygons or elongated ellipsoids or arcs. For example, a slot may also be writable by a (non-square, i.e. elongated) rectangle having a width bu_ and a length LL. A rectangular slot may have a length LL ranging from about 2% to about 13% of the longest dimension of the abrasive article, particularly in the range of 2.5% to 6.5%. In particular, a slot may have a length LL which is in the range of 3 mm to about 20 mm, in particular in the range of 4 mm to 10 mm. In one embodiment, a rectangular slot has a length LL of 5 mm. A rectangular slot may have a width bu_ that ranges from about 0.5% to about 10% of the longest dimension of the abrasive article, particularly in the range of 1.0% to 3.0%. In particular, a rectangular slot may have a width bLL which is in the range of 0.75 mm to about 15 mm, in particular in the range of 1.5 mm to 4.5 mm. In one embodiment, a slot has a width bLL of 2.0 mm, 2.4 mm or 3.0 mm.

It should be noted that a slot is not a "cut" as it is known in the art, Such slots can not be specified by a width bLL or by a radius H_L, as they are merely intersected are produced in the abrasive article (correspondingly bLL = H_L = 0 mm) .In particular, such slots have no surface area such slots have a fundamentally different effect due to their different nature - in particular, flow physical properties between slots according to the invention and said slots are not comparable due to the dynamic pressure required to open a slot.

The holes of the abrasive article, both substantially circular holes, circular holes and elongated holes, can be formed by embossing, stamping, laser cutting or combinations thereof in the backing layer and the abrasive coating (sum of the coating of the backing layer). In one embodiment, the holes are punched in the abrasive article. In a further embodiment, the holes are cut into the abrasive article by means of a laser beam, in particular fired.

By "a plurality of holes" is meant more than 20 holes, more particularly more than 40 holes, more particularly more than 50. An abrasive article embodied as an abrasive article in one embodiment has a hole pattern of at least about 20, more preferably at least about 50, whole In particular, the number of holes is not greater than about 300, in particular not greater than about 200, in particular not greater than about 150. The plurality of holes are arranged in a hole pattern In an alternative embodiment, at least 50% of the holes form the plurality of holes arranged in a pattern of holes At least 70% of the holes make up the Me number of holes arranged in a pattern of holes. Alternatively, at least 90% of the holes form the plurality of holes arranged in a hole pattern.

The hole pattern may cover (ie, be spread over) the entire abrasive article, may substantially cover the entire abrasive article (ie, greater than 50% but less than 100%), may cover multiple portions of the abrasive article, or may cover only a portion of the abrasive article. A measure of the degree of coverage of the abrasive article by the hole pattern can, for example, Be given over the covered by an envelope of the hole pattern surface of the abrasive article. Thus, "covering the entire abrasive article" means that the envelope of the hole pattern covers the entire surface of the abrasive article, the area of the envelope and the area of the abrasive article are the same.For one example of an abrasive article as a grinding wheel, the hole pattern may be defined by an envelope in FIG If this envelope then has a radius equal to the radius of the grinding wheel, the hole pattern covers the entire abrasive article If the radius of the envelope is slightly smaller than the radius of the grinding wheel, the hole pattern substantially covers the entire Abrasive article (ie, more than 50% but less than 100%, preferably more than 70% but less than 100%, more preferably more than 85% but less than 100%.) In particular, an abrasive article may be realized such that an edge of an outermost one Holes of the hole pattern the edge of the S abrasive article cuts. Alternatively, an abrasive article may also be implemented such that an edge of an outermost hole of the hole pattern has at least a measurable distance from the edge of the abrasive article. Furthermore, an abrasive article is conceivable in which the hole pattern covers only a part of the surface, ie a spatially limited surface portion, of the abrasive article. The "envelope" is to be understood in particular as meaning a curve, for example a circle, a circular ring, a rectangle or also a different geometric shape, which envelopes or envelopes the hole pattern.

By "covering a plurality of parts of the abrasive article" it can then correspondingly be understood that although the hole pattern can be described by an envelope, regions which are not interspersed with holes in the hole pattern exist in this envelope, in particular. Covered spaced apart portions of the surface of the abrasive article, that is, distributed over the abrasive article that are formed between areas that have holes, areas that have no holes.Especially, this spaced distribution can be realized evenly or uniformly.

The number and the area of the holes determine the area of the abrasive article that is actually available as a grinding surface (not: maximum) - this corresponds to the maximum surface area available as grinding surface (see above) minus the surface area formed by the totality of the holes. The surface area of the abrasive article that is actually available as a grinding surface decisively determines the grinding properties of the abrasive article, in particular the amount of a material removed from a processing surface during a grinding process. Typically, the amount of material removed increases with increasing surface area of the abrasive article available as a grinding surface. Furthermore, the number and area of the holes affect a suction behavior during suction of grinding dust from the intermediate area between the abrasive article surface and the processing surface during a grinding process on the processing surface. In particular, there will typically be a tendency for abraded material, particularly abrasive dust, to accumulate on the abrasive article surface as the surface area of the abrasive article available as the abrasive surface increases.

A number of holes and their summed size define an area Ai_ of the corresponding holes. Based on an area As of the abrasive article on which the holes are arranged, a hole density p = AJAs can thus be defined. In particular, a "hole density of an entire hole pattern" of the abrasive article may be defined as the ratio of Ai_ of the corresponding holes of the entire hole pattern to the total area As of the abrasive article and an outer area, wherein the hole density ρι (pi = Ai_-mnen / As-inside) of the inner area of the hole pattern decreases toward the hole density PA (PA = Ai_-outer / As-outer) of the outer area of the hole pattern, pi> PA.

The hole pattern - and in particular also the abrasive article, when the hole pattern substantially covers the entire abrasive article - is subdivided into at least one inner area and one outer area, wherein the outer area completely encloses the inner area. The inner area and the outer area can be defined, for example, as separate areas via geometric shapes, wherein the geometric shape that describes the outer area completely encloses the geometric shape that describes the inner area. In particular Both the interior and the exterior are immediately adjacent to each other, so that geometrical sizes of the interior area typically form geometric dimensions of the exterior. In one embodiment of the abrasive article as a substantially circular grinding wheel, the inner region and the outer region may be arranged concentrically with one another. Further, the inner area and the outer area may be concentric with the center (geometric center or center of gravity) of the hole pattern. In particular, the inner region can represent a circular disk with radius grooves, while the outer region represents a circular ring immediately adjacent to the inner region, whose smaller radius corresponds to grooves and whose larger one

Radius R _on the diameter of the hole pattern, in particular the diameter of the envelope of the hole pattern, in particular the diameter of the grinding wheel corresponds. In particular, the radius R _can be twice the radius of the grooves, in particular three times the radius of the grooves. For example, a substantially circular grinding wheel of 15 cm diameter may have an interior area with a radius of 3.75 cm (area inside = 44.2 cm ² ) and an outside area with a smaller radius of 3.75 cm and a larger radius R _out of 7.5 cm (Area As-Out = 132.5 cm ² ) (for a total area of the grinding wheel of As-total = 176.7 cm ² ). Both the indoor and outdoor areas each have at least one

Hole on, so that a hole density for indoor and outdoor can be specified. According to the invention, the hole density of the outer region is selected smaller than the hole density of the inner region. Alternatively or additionally, the inner area and the outer area can also be defined by a ratio of the surface area of the outer area to the area of the inner area. In the abovementioned exemplary embodiment of the abrasive article in the form of a grinding wheel, in which the inner region represents a circular disk with radius grooves, while the outer region represents a circular ring with a larger (outer) radius R _out immediately adjacent to the inner region, a ratio corresponding to FIG Area contents, for example, be 2: 1, in particular 3: 1, very particularly 4: 1, 8: 1 or 15: 1 amount. Furthermore, it is also conceivable to define the inner area and the outer area by means of their hole densities, the hole density of the inner area differing advantageously from the hole density of the outer area. For example For example, an interior can have a uniform distribution of holes with a hole density of 8%, while the outside area has a uniform distribution of holes with a hole density of 3%. The erratic difference in hole density is immediately recognizable on the abrasive article and clearly differentiable by a boundary between interior and exterior. Thus are

Interior and exterior clearly separated and defined.

In the case of a non-circular abrasive article corresponding interior and exterior areas are analog defined. For example, a substantially rectangular abrasive article may have an interior region in the form of an "inner rectangle" and an exterior region in the form of an "outer rectangle", the "outer rectangle" completely enclosing the "inner rectangle". In the case of an abrasive belt, it is conceivable for the belt-shaped abrasive article to have an inner region in the form of an "inner strip" and an outer region in the form of two "outer strips", the two "outer strips" completely enclosing the "inner strip".

Taking into account the actual surface area available as a sanding surface, the total area of holes available for dust extraction, the location of the dust extraction holes on the abrasive article, and their relation to the movement of the abrasive article during a sanding process, it is believed that the present invention will be appreciated Invention, a relatively high density of the inner area, compared with the hole density in the outer area, a particularly advantageous effect on the grinding properties of the abrasive article, in particular the grinding wheel to have ben. A Staubabsaugfähigkeit the abrasive article can in contrast to

Abrasive articles of the prior art can be significantly improved.

This approach according to the invention is in contrast to previous approaches to maximize the amount of extracted grinding dust, which only have the goal to introduce as many holes in the abrasive article as possible to the

Extracting available hole area to increase compared to the abrasive surface available as a grinding surface. However, the multiplicity of small holes in the abrasive articles known from the prior art often lead to problems with a mechanical and / or structural stability of the abrasive article. Especially in areas of an abrasive article in which Many small holes are present - typically accumulated in the prior art against the edge of the abrasive article - often results in a significantly increased tendency for the abrasive article to tear. The tearing takes place on the basis of physical forces such as shearing forces, torsional forces or the like which act on the abrasive article as a result of a rotational movement, eccentric movement and / or orbital motion. Furthermore, the multiplicity of small holes in the prior art abrasive articles results in an apparently unfavorable increase in hole density at which, starting at a certain ratio of holes to the abrasive surface of the abrasive article available as the abrasive surface, a material erosion effect and a lifetime of the abrasive article

Abrasive article drops sharply.

The proposed approach according to the invention, however, can overcome such disadvantages of the prior art. According to previous findings, a comparatively high hole density in the interior region of the abrasive article - compared with a hole density of the outer region of the abrasive article (not always repeated below) - leads to advantageous flow physical properties between the abrasive article and the processing surface. It is assumed that the high hole density in the interior of the abrasive article leads to a more uniform, in particular more laminar and turbolenzfreieren, flow of sucked air, so transported with the air flow ("transported") material such as sanding dust evenly moved or out, and thus more reliable In other words, the so high density of holes in the interior of the abrasive article leads to a reduction of a "nozzle effect", the nozzle effect signifying an increase in air velocity compared to an undisturbed air flow caused by a constriction of the flow cross section ( an associated crowding of streamlines leading to an increase in speed).

It is believed that the distribution of higher inner hole density to lower outer hole density correlates directly with the rotational speed of the abrasive article in a typical application with an orbital sander or orbital sander. So it was found that a high rotational speed of the holes in the outdoor area of the Abrasive article, in particular the grinding wheel, advantageously combined with a low hole density in the outdoor area. This effect may possibly also be explained by reference to a (comparatively) acceleration of the air flow in the outer area of the abrasive article due to the comparatively low hole density (nozzle effect). By increasing the hole density in the inner region, a reduction of air flowing radially from the outside to the center of the grinding wheel in the inner region of the abrasive article can evidently take place, so that the air flow (ie air pressure or flow suction) in the outer region of the abrasive article is advantageously increased by the holes located in the outer region can. As a result, the suction power can be increased, which, despite the comparatively higher speed of rotation in the outer region, leads to particularly good properties in the removal of the removed material, in particular of the sanding dust to be sucked off, and thus in the sanding result. Thus, the present invention realizes an abrasive article to advantageously reduce the effect of the nozzle effect in the interior of the hole pattern, in particular the Schleifartikels.advantageously, while the effect of the nozzle effect in the outer region of the hole pattern, in particular the abrasive article, is advantageously increased.

It should be noted that the advantageous, comparatively high hole density in the inner region of the hole pattern can be stably realized only by introducing elongated holes, in particular in the inner region of the hole pattern. By using the slots according to the invention, a number of comparatively thin connecting struts between individual adjacent holes (which would be numerous if desired high hole density) can be reduced and thus tearing of the abrasive article - in particular as a result of the grinding process - can be prevented. By using elongated holes and / or correspondingly wide connecting struts-which are shaped rather as connecting surfaces-shearing, torsional and transverse forces acting during a grinding process can thus be better absorbed and absorbed on account of an overall more stable geometry of the abrasive article. In particular, therefore, a particularly stable abrasive article can be given with said advantageous properties. Thus, advantageously, a long-term stability of the abrasive articles realized with oblong holes compared to abrasive articles without slots - Especially with an increased number of individual holes - be significantly increased.

Furthermore, it is assumed that the relatively large surface area resulting from the large hole density Absaugfläche (especially known from the prior art abrasive articles) in the interior of the abrasive article leads to a less punctual and thus gleichverteilteren or homogeneous suction especially in the interior. In other words, due to its geometrical extension, a slot can cause a "collection effect." This effect is reinforced by the already mentioned (assumed) more laminar and turbulence-free flow of sucked air in the interior of the abrasive article.

In one embodiment, the hole density in the interior of the hole pattern is between 7.5% and 16.0%, in particular between 8.5% and 13.0%, very particularly between 9.0% and 12.0%. In one embodiment, the hole density in the outer region of the hole pattern is between 1.5% and 4.8%, in particular between 2.0% and 3.8%, very particularly between 2.9% and 3.4%. The described effect occurs according to current knowledge to a particularly advantageous extent for such hole pattern having a ratio of the hole density pi of the inner region to the hole density PA of the outer region, which is in the range between 1.9% and 6.9%, in particular in the range between 2.8% and 6.0%, more particularly in the range between 3.1% and 5.7%.

In one embodiment, the hole density of the entire hole pattern is between 2.6% and 6.8%, in particular between 3.0% and 6.5%, in particular between 3.5% and 5.5%. With such a selected hole density of the entire hole pattern in combination with the above-mentioned hole densities in the interior and exterior of the hole pattern, in particular in combination with the preferred ratios of the hole density pi of the inner region to the hole density PA of the outer region, are particularly good results in the abrasive effect, in particular Achieved grinding efficiency, long-term stability and low clogging of the grinding surface. It should be noted that a stable realization the said high hole density in the interior can only be specified by the introduction of the inventive elongated holes with a constant or decreasing number of holes.

In an embodiment, the number of slots in an inner area of the hole pattern is larger than the number of slots in an outer area of the hole pattern. In this way, the advantageous, inventive distribution of the hole densities of the inner region and the outer region can be particularly easily realized. For example, a hole pattern in an inner area 24 may have long holes and in an outer area only 8 slots.

In one embodiment, an elongation and / or a radius of a first slot, in particular a slot in the interior of the hole pattern, are different from an elongation and / or a radius of a second slot, in particular a slot in the outer area of the hole pattern. In particular, an elongation and / or a radius of a first slot, in particular of a slot in the inner area of the hole pattern, is greater than an elongation and / or a radius of a second slot, in particular a slot in the outer area of the hole pattern. In this way, a surface area of a hole is particularly easy to influence and thus the hole density in the interior and in the outside area precisely tuned and to achieve particularly advantageous grinding properties of the abrasive article. In particular, a grinding effect and grinding efficiency can be so particularly finely adjustable. In particular, for example, an abrasive article is conceivable, which has slots both in the interior and in the outer area, with an elongation of the elongated holes decreases from the inside to the outside and / or decreases a radius of the slots from the inside to the outside. Furthermore, the mechanical properties of the abrasive article can be advantageously adjusted, in particular variably adjusted via the abrasive article, so that a special tear resistance of the abrasive article can be achieved.

In one embodiment of the abrasive article, the hole pattern is a symmetrical hole pattern, in particular a rotationally symmetrical and / or rotational symmetry pattern. metric and / or axisymmetric and / or point symmetric and / or translational symmetric hole pattern. Thus, the hole pattern has the property of being imaged onto itself using a corresponding symmetry mapping or symmetry operation, ie, by appropriate rotation and / or rotation and / or mirroring and / or translation or the like. Examples of such symmetrical hole patterns may be regular patterns (holes arranged in rows and columns), radial patterns (holes arranged in radial rays around a central point), spiral patterns (holes arranged in spirals), repeatedly arranged curve patterns (holes arranged in a curve). or the like. A symmetrical hole pattern can be produced in a particularly simple manner. Furthermore, due to their number of symmetry, symmetrical hole patterns permit a particularly simple attachment to a sanding pad, since alignment of the sanding article with respect to the sanding pad is possible with little effort.

In an alternative embodiment of the abrasive article, the hole pattern is an asymmetrical hole pattern, in particular a rotationally asymmetric and / or rotational asymmetric and / or axis asymmetric and / or puncture symmetrical and / or translational asymmetrical hole pattern. In particular, hole patterns are conceivable which have a controlled non-uniform distribution and therefore have a corresponding asymmetry. A "controlled non-uniform distribution" is to be understood in particular as meaning that the hole pattern has a deliberately created, in particular calculated or otherwise unambiguously given-and therefore reproducible-but nevertheless asymmetrical arrangement. In one embodiment, a controlled non-uniform distribution may be provided by realizing a helical hole pattern in which holes are arranged to result in complete rotational asymmetry - that is, the hole pattern repeats upon rotation by 360 ° only once (congruence only with 360 ° rotation) In particular, rotational asymmetry refers to asymmetry in rotation about the center - defined as the geometric center or center of gravity - of the hole In one embodiment of the abrasive article obey all the holes of the hole pattern of purposefully created, in particular calculated or otherwise clearly predetermined, but still asymmetric arrangement. Alternatively, only parts of the hole pattern of the purposefully created, in particular calculated or otherwise clearly predetermined, but still asymmetrical arrangement obey. For example, it may be provided that a large part of the holes of the hole pattern obey the purposefully created, in particular calculated, or otherwise uniquely predetermined, but nevertheless asymmetrical arrangement. In this context, a "majority of the holes" should be understood as meaning, in particular, at least more than 50%, preferably at least more than 70% and particularly preferably at least more than 90% of the holes In one embodiment, the hole pattern has a specifically created, in particular calculated or otherwise clearly predetermined, but nevertheless asymmetric arrangement over at least 20 holes, in particular over at least 40 holes, in particular over at least 60 Lö., It is an abrasive article conceivable in which a rotational asymmetry up to at least 51%, at least 70th % or at least 85% of the holes of the hole pattern runs.

An asymmetrical distribution of the hole pattern reinforces the effects of a particularly advantageous extraction on which the invention is based. On

Because of the asymmetric distribution of the holes in the hole pattern, in a typical application with an orbital sander or orbital sander, there are less shadowing effects of the (especially adjacent) holes with each other. In particular, the asymmetric distribution can result in a very uniform or homogeneous hole distribution over the abrasive article, so that regions that have no holes are similarly sized throughout the abrasive article. In addition, with respect to the typical rotational motions and / or orbital motions when used with an orbital sander or orbital sander, deviations from a symmetrical distribution are advantageous in that outermost holes do not significantly obstruct or disturb an airflow to a more inward hole, ie shade the inside hole. Consequently, an air flow to all holes distributed on the abrasive article can be ensured, so that an advantageous extraction of removed material, in particular grinding dust, over the entire surface of the abrasive article is possible. In addition, it has been found that the distribution of holes in an asymmetric hole pattern results in a typical rotational movement and / or orbital motions of the abrasive article, such as used with an orbital sander or orbital sander, that portion of the working surface which is completed during a full cycle Rotation of the abrasive article is swept by at least one hole of the abrasive article, compared to an abrasive article with a symmetrical hole pattern is larger - at comparable hole density and number of holes. In particular, in the case of an asymmetrical hole pattern, repeated sweeping through several holes will not take place, as is the case with symmetrical hole patterns. Thus, an asymmetrical hole pattern allows more uniform over the processing surface suction of removed material, in particular grinding dust.

In one embodiment of the abrasive article, the hole pattern describes at least one spiral line, preferably a plurality of spiral lines, wherein holes of the hole pattern are arranged along the spiral line (spiral lines). By "spirals or spirals" herein is meant a curve or set of curves originating from at least one central point (starting point) on the abrasive article and rotating away from the at least one central point In particular, a map of the spiral line in a polar coordinate system is at least simply continuously differentiable, with the central point at or near the center of the abrasive article or alternatively from the center of the abrasive article In particular, a plurality of spiral lines (hereinafter "spirals" and "spiral lines" are synonymous) may also start from different central points or emanate from a common central point never, an Eulerian spiral line, a Cornu spiral line, a clothoid, a Fermat spiral line, a hyperbolic spiral line, an Auger spiral line, a logarithmic spiral line, a Fibonacci spiral line, a golden spiral line (or spiral lines), or combinations thereof describes. In one embodiment of the abrasive article, the hole pattern describes at least one of the at least one spiral line opposing at least one spiral line. Tere spiral line, preferably a plurality of, the at least one spiral line oppositely oriented, further spiral lines are arranged along the holes of the hole pattern. In particular, all holes of the hole pattern can be arranged along the at least one spiral line and the at least one oppositely oriented spiral line. In particular, the at least two spiral lines may be opposite to each other with respect to a spiral axis of the spiral lines. In this context, "counteracting" should be understood in particular to mean that the spiral lines extend in opposite directions about their spiral axes away from the respective central points (starting points).

By using at least one spiral line, in particular by using a plurality of spiral lines, preferably by using oppositely oriented spiral lines, a particularly advantageous distribution, in particular a particularly homogeneous distribution, of the holes on the abrasive article can be achieved. In one embodiment, the opposing spiral lines differ in number. By this is meant in particular that a number of spiral lines which extend in one direction, in relation to the number of spiral lines, which are opposite to these spiral lines, different. In particular, it can be achieved in this way that an asymmetrical hole pattern with an advantageous area utilization and an advantageous area distribution is achieved. In one embodiment, the number (m) of the spiral lines that run in one direction and the number (n) of the spiral lines that are opposite to those spiral lines correspond to Fibonacci numbers or multiples of Fibonacci numbers. In an exemplary embodiment, the numbers have the following values for (m, n): (3, 5), (5, 8), (8, 13), (13, 21), (21, 34), (34, 55), (55, 89), (89, 144) or multiples of these values. By such a configuration of the hole pattern can be achieved that the holes of the hole pattern are evenly distributed over the surface of the abrasive article, while it can be prevented that holes in the radial direction directly behind each other (shading effect in dust extraction). In one embodiment of the abrasive article, the at least one spiral line and the at least one further, oppositely oriented, spiral line intersect at least once. Furthermore, multiple intersections may result in multiple counter-aligned spiral lines. In this way it can be realized very simply that a high hole density is applied, which decreases according to the invention from an inner area to an outer area of the hole pattern.

By "arranged along a spiral line" or generally also "arranged according to a hole pattern" is meant that the position of the holes is substantially writable by a corresponding geometric figure of the hole pattern (e.g., a spiral). By "substantially" in this context is meant, in particular, that a distance from a predetermined (ideal) position is in particular less than 100%, preferably less than 50% and particularly preferably less than 25% of a diameter of a corresponding hole.

In particular, all holes of the hole pattern can be arranged along the at least one spiral line, preferably along the plurality of spiral lines. In this way, a particularly advantageous, uniform distribution of the holes over the abrasive article can be achieved. In particular, it is conceivable that the distances of in each case two holes which directly follow one another along a spiral line vary by less than 60%, particularly preferably by less than 50%, from the greatest distance between two successive holes. As a result, a particularly favorable and uniform distribution of the holes can be achieved.

In one embodiment, the at least one spiral line is described only through holes of the interior or the exterior. Alternatively, the at least one spiral line is described by holes of the inner area and the outer area. In an exemplary embodiment, the hole pattern describes at least four spiral lines, in particular at least eight spiral lines, in particular at least sixteen spiral lines. In one embodiment of the abrasive article, in each case at least three holes, preferably in each case at least five holes, particularly preferably in each case at least seven holes, are arranged along a spiral line. In this way, a particularly homogeneous distribution of the holes over the abrasive article can be achieved and thus a suction efficiency and suction efficiency can be increased. In particular, the holes arranged along a spiral line are equidistant or arranged with outwardly increasing distances from each other. In one embodiment of the abrasive article, in each case at least one elongated hole, preferably in each case at least two elongated holes, particularly preferably in each case at least three elongated holes, are arranged along a spiral line. In this way, the suction efficiency and suction efficiency can be increased again, in particular if the

Long holes are arranged in the interior of the hole pattern.

In one embodiment of the abrasive article, a respective oblong hole is arranged aligned along a spiral line such that an axis defined by the elongation of the oblong hole extends substantially tangentially to the spiral line. By "substantially tangential" is meant, in particular, that a deviation of the orientation is less than 10 °, preferably less than 5. Further, a slot may also be arranged slightly offset parallel to the spiral line, wherein the axis of the slot parallel to the tangent Such a hole pattern is particularly advantageously adapted to a typical movement of the abrasive article during a typical rotational movement and / or orbital motion of the abrasive article as encountered in use with an orbital sander or orbital sander In this way a mechanical stability and a kinematic stability of the abrasive article during a grinding process can be increased.

Tearing of the abrasive article and vibrations caused by slight "fluttering" of the abrasive article (presumably due to air turbulence) may be advantageously reduced. It is believed that the fluidic properties of the abrasive article during a grinding process are limited by the placement of the abrasive article Slotted holes, one of which

Elongation of the slot defined axis essentially forms a tangent to a corresponding spiral line, causing corresponding advantageous effects.

In one embodiment of the abrasive article, the hole pattern has a center hole, with a tangent to the center hole forming a tangent to the at least one spiral line and / or with one tangent to the center hole forming a tangent to each one of the plurality of spiral lines , By using the center hole, the hole density in the interior of the hole pattern can also be further increased. Furthermore, an alignment of the abrasive article with respect to a sanding plate when arranged on a Sanding plate can be simplified because the abrasive article with a mark located on the sanding pad, for example, a central bore or a central screw of the sanding pad can be brought into line. Furthermore, the grinding properties are improved if the at least one spiral line and / or the at least one further spiral line has a tangent which forms a tangent to the center hole. It is believed that such an eccentric spiraling tangential to the center hole additionally increases the hole density in the inner region - unlike, for example, a spiral line that would extend directly into a center hole. Furthermore, such a hole pattern is particularly well adapted to a rotational movement and / or orbital movement of the abrasive article, as it occurs when used with an eccentric or orbital sander.

drawings

The invention is explained in more detail in the following description with reference to exemplary embodiments illustrated in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. Like reference numerals in the figures indicate like elements.

Show it:

Fig. 1 is a schematic representation of an embodiment of a

Abrasive article according to the prior art;

Fig. 2 shows a system with an inventive abrasive article and a

Grinder and a processing surface in a schematic representation;

3 is a greatly enlarged detail of a schematic sectional view of an embodiment of an abrasive article according to the invention;

4 shows a schematic illustration of a first embodiment of an abrasive article according to the invention;

Fig. 5 is a schematic representation of an exemplary embodiment of a slot; Fig. 6 is a schematic representation of a second embodiment of an abrasive article according to the invention;

7 shows a schematic illustration of a third embodiment of an abrasive article according to the invention;

Fig. 8 is a schematic representation of a fourth embodiment of an abrasive article according to the invention.

FIG. 1 shows an abrasive article 110 as known from the prior art. The abrasive article 110 is realized as a coated abrasive wheel intended for use with a commercially available sander 200 (e.g., an orbital sander or orbital sander) - see Figure 2 -. The abrasive article 110 has a plurality of holes 112 disposed in a hole pattern 114. The holes 112 are realized as perforations, which are the suction of during the grinding process on a

Processing surface 202 (see Figure 2) produced material removal, in particular grinding dust or other material, by means of a suction device of the grinder 200 serve. The holes 1 12 are realized as circular, equal-sized holes. The holes 112 have a radius n_ of about 1.2 mm. The holes 112 of the abrasive article 110 are introduced by, for example, punching or laser cutting into a previously prepared abrasive article 110 that does not yet include holes 112. The illustrated abrasive article 110 has a total of one hundred and twenty holes 12, all holes 12 together forming the plurality of holes arranged in a hole pattern 114. The hole pattern 114 essentially covers - i. E. except for a narrow, negligible edge distance (the envelope of the hole pattern, ie a circle enclosing the hole pattern, here has a radius of more than 0.95 Raußen - consequently the hole pattern covers more than 90% of the grinding wheel and thus substantially the entire grinding wheel ) - the entire abrasive article surface 116 of the abrasive article 110.

The hole pattern 1 14 and here also the abrasive article 1 10 are divided into an inner area 1 18 and an outer area 120, wherein the outer area 120, the inner area 1 18 completely encloses. In the illustrated embodiment of the abrasive article 1 10 as a substantially circular grinding wheel are the

Inner area 1 18 and outer area 120 are arranged concentrically to one another, wherein the inner region 1 18 and the outer region 120 are arranged concentrically to the center 122 of the hole pattern 1 14 and the abrasive article 1 10. The inner region 1 18 thereby represents a circular disk 1 19 with radius grooves of 7.5 cm, while the outer region 120 is an adjacent to the inner region 1 18 annulus 121 whose inner radius corresponds to 7.5 cm inside and whose larger radius R _aU corresponds to the diameter of the abrasive article 1 10 (ie the grinding wheel) of 15 cm. The inner area 1 18 has an area of As inside = 44.2 cm ² , while the outer area 120 has an area As-Au en = 132.5 cm ² . The total area of the abrasive article 110 is As total = 176.7 cm ² . The interior 1 18 has a total of forty-two

Holes 1 12 (with a total hole area of Ai_-inside = 1, 9 cm ² ), while the outer area 120 in total seventy-eight holes 1 12 has (with a total hole area of Ai_-outside = 3.5 cm ² ). The hole density of the outer region 120 is 2.7%, while the hole density of the inner region 1 18 is 4.3%. The hole density of the entire hole pattern is 3.1%.

FIG. 2 shows a grinding device 200, which is formed by an eccentric or orbital sander and serves to grind a processing surface 202. The grinder 200 has a housing 204, which encloses a non-illustrated, formed by an electric motor drive unit. The drive unit is supplied with electrical energy in an operating state by means of a power cable 206, which is arranged at one end of the housing 204. Alternatively, the grinder may be battery powered. To activate the drive unit, a switching element 208 is provided, which is displaceably mounted in the housing 204. The switching element 208 is formed by a slide switch. The housing 204 forms a first, cylindrical handle region 210, which is arranged on the end facing the power cable 206. Furthermore, a further grip region 212 is provided which is arranged on an end of the housing 204 facing away from the power cable 206. The further handle portion 212 is formed dome-shaped. The first grip area 210 and the further grip area

212 are intended to be encompassed by a hand of an operator and to relatively guide the grinder 200 in an operating state, in particular to guide relative to a processing surface 202. At the end of the grinder 200 facing away from the power cable 206, a tool holder 214 is arranged. The tool holder 214 connects to the housing 204. The Tool holder 214 comprises a grinding plate 216. The tool holder 214 is intended to receive an abrasive article 110, 10a-d, in particular a grinding wheel. The abrasive article 110, 10a-d, particularly the abrasive wheel, and the sander 200 together form a system.

The abrasive article 110 of FIG. 1-as well as the abrasive article 10a-d according to the invention shown below in FIGS. 4, 6-8-are intended to be reversibly detachably connected to such a sanding pad 216 of such a sanding device 200. In the activated state of the grinder 200 while the sanding pad 216 is attached together with it

Abrasive article 110,10a-d driven by the grinder 200, in particular in a rotational movement and / or eccentric movement and / or orbital movement, moves. As shown in a schematic, greatly enlarged sectional view in FIG. 3, each of the coated abrasive articles 110, 10a-d described here comprises a carrier element 124. The carrier element 124 in the exemplary embodiment is made of a paper or of a cardboard, alternatively for example also Vulcanized fiber and serves as a flexible support for the abrasive pad 126 applied thereon. The abrasive pad 126 includes abrasive grains 128 and a binder 130 (base binder) that bonds the abrasive grains 128 and the paper or board together. The binder 130 may be made of, for example, a phenolic resin. The abrasive pad 126 forms a grinding surface 132 (abrasive article surface). The carrier element 124 has a round main extension surface (see FIGS. 1, 4 and 6 to 8), wherein the grinding surface 132 extends parallel to the main extension surface of the carrier element 124. The support member 124 of the abrasive article 110,10a-d is disc-shaped and here has a diameter of 15 cm. On one side of the carrier element 124 opposite the grinding surface 132, a receiving region, not shown here, is arranged. The receiving area comprises a hook-and-loop element which is intended to correspond to a hook-and-loop element of the sanding plate 216 of the sanding device 200 and to adhere in an adhesive manner. The hook and loop element is firmly connected to the carrier element 124 of the abrasive article 110, 106a-d and runs parallel to the main extension surface of the carrier element 124. The holes 112, 12a-d introduced into the abrasive article 110, 10a-d penetrate the latter Carrier element 124 and the abrasive pad 126 completely. The holes 112, 12a-d penetrate the abrasive article 110, 10a-d substantially parallel to each other (not shown in detail here). The holes 112, 12a-d form a suction surface parallel to the main extension surface of the carrier element 124. The suction surface encompasses the total area of the free spaces 134 enclosed by holes 112, 12a-d. The holes 112, 12a-d form a hole pattern, viewed parallel to the main extension surface of the carrier element 124 (see FIGS. 1, 4 and 6 to 8) (There reference numerals 114,14a, 14b, 14c, 14d)), wherein in the embodiments illustrated here, the hole pattern over the entire main extension surface of the support member 124 of the abrasive article 110,10a-d extends. Furthermore, the layer of binder 130 and abrasive grains 128 may be coated with a capping agent 136, for example, phenolic resin.

The abrasive article 110 shown by way of example in FIGS. 1 and 3 and the application on the sanding device 200 illustrated in FIG. 2 form the starting point for the following description of exemplary embodiments of the proposed abrasive article 10a-d according to the invention Grinding articles 110 of the prior art differs. The proposed abrasive article 10a-d has a basically similar structural configuration and serves the same purpose or the same application as a prior art abrasive article 110. The nomenclature and background information introduced in the context of FIGS. 1 to 3 can therefore be transferred directly to the exemplary embodiments of the inventive abrasive article 10a-d shown in the following figures.

FIG. 4 shows an abrasive article 10a according to the invention in the form of a circular grinding wheel. The abrasive article 10a has a diameter of 15 cm. The abrasive article has a plurality of holes 12a for exhausting abrasive dust from a work surface 202 during a grinding process on the work surface 202. The plurality of holes 12a are arranged in a hole pattern 14a, with the hole pattern 14a covering the entire abrasive article 10a - ie, except for a narrow, negligible edge distance (the envelope of the hole pattern, ie a circle including the hole pattern, here has a radius of more than 0.92 roughness - thus the hole pattern covers more than 85% of the grinding wheel and thus essentially the entire grinding wheel). As already introduced in connection with FIG. 1, the hole patterns 14a-d of the abrasive articles 10a-d described below are subdivided into a respective inner region 18a-d and a respective outer region

20a-d, wherein the outer region 20a-d completely surrounds the inner region 18a-d. The respective inner regions 18a-d and the respective outer regions 20a-d are arranged concentrically with one another and are furthermore arranged concentrically with the center 22a-d of the hole pattern 14a-d. The respective inner region 18a-d represents a circular disk 19a-d with radius grooves of 7.5 cm, while the respective outer region 20a-d represents a circular ring 21 ad adjoining the respective inner region 18a-d, whose smaller radius is grooves 7, 5 cm and whose larger radius Rausen corresponds to the diameter of the abrasive article 10a-d (ie the respective grinding wheel) of 15 cm (as explained, the edge is negligible here).

The hole pattern has twenty holes 12a formed as slots 35a, which are partially arranged in a star shape and symmetrically in the inner area 18a of the hole pattern 14a. In each case six elongated holes 38a form two mutually perpendicular axes 40,42, which also each have a symmetry axis of the

Hole pattern 14a form underlying mirror symmetry. In the center 22a, the hole pattern 14a has a center hole 44a having a diameter of 10 mm (area 78.5 mm ² ). Furthermore, eight further elongated holes 38a are arranged around this center hole 44a. As shown in FIG. 5, a corresponding oblong hole 38a (as well as the oblong holes 38b, 38c, 38d described in the following FIGS. 6, 7 and 8) can be described by a radius η_ι_ and a length LL and defines an axis which is given by the direction of the elongation (ie in the direction of the length LL) (see here the axes 40,42). The illustrated elongated holes 38a (as well as 38b, 38c and 38d in FIGS. 6, 7 and 8, respectively) each have a length LL of 5.25 mm and a radius H_L of 1.05 mm. The

Long holes 38a have an area of 200 mm ² in total.

Furthermore, the hole pattern 14a in the inner region 18a has twenty-six circular holes 13a of equal size. The circular holes 13a have a radius n_ of about 1.5 mm (with a total hole area of AL inside = 1.8 cm ² ), while the outer portion 20a has seventy-two circular holes 13a in total (with a total hole area of Ai_ outer = 5.1 cm ² ). The hole density of the outer region 20a is 3.8%, while the hole density of the inner region 18a is 10.5%. The hole density of the entire hole pattern is 5.5%. The hole density of the hole pattern 14a decreases from the inner area 18a of the

Hole pattern 14a to the outer region 20a of the hole pattern 14a clearly from. The ratio of inner hole density to outer hole density is 2.8. FIG. 6 shows an inventive abrasive article 10b in the form of a circular grinding wheel. The abrasive article 10b has a diameter of 15 cm. The abrasive article 10b has a plurality of holes 12b for sucking off abrasive dust from a work surface 202 during a grinding process on the work surface 202. The plurality of holes 12b are arranged in a hole pattern 14b, with the hole pattern 14b covering the whole

Abrasive article 10b covered - i. except for a narrow, negligible edge distance (the envelope of the hole pattern, ie a circle enclosing the hole pattern, here has a radius of more than 0.98 Raußen - consequently covers the hole pattern more than 96% of the grinding wheel and thus essentially the entire grinding wheel). The hole pattern 14b represents a rotationally symmetrical hole pattern 14b (eightfold). The hole pattern 14b describes eight spiral lines 46 along which holes 12b of the hole pattern 14b are arranged. The hole pattern 14b has, in the inner region 18b, twenty-four holes 12b formed as elongated holes 38b, which are arranged along the spiral lines 46. In this case, the spiral lines 46 extend in a common direction of rotation (here counterclockwise). Per spiral line 46, three elongated holes are arranged along the corresponding spiral line 46. The respective elongated holes 38b are arranged aligned along a respective spiral line 46 such that an axis 50 defined by the elongation of the slot 38b extends substantially tangentially to the spiral line 46. In the center 22b, the hole pattern 14b has a center hole

44b, which has a diameter of 10 mm (area 78.5 mm ² ). The spiral lines 46 are formed such that a tangent to the spiral line represents, as it were, a tangent to the center hole 44b. The elongated holes 38b have a radius n_i_ of 1.05 mm and a length Ιι_ι_ νοη 5.25 mm. The slots have an area of 240 mm ² in total. Further, each spiral line 46 has four further circular holes 13b arranged along the respective spiral line 46, the three outer circular holes 13b being located in the outer area 20b of the abrasive article 10b and one circular hole 13b still being located in the inner area 18b. The circular holes 13b have a radius n_ of about 1.5 mm.

The hole pattern 14b thus has in the inner region 18b on a pinhole area of the inside-AI_ = 3.5 cm ^2), while the outer area 20b = area of a hole AI_ outer 2.0 cm ^2. The hole density of the outer region 20b is therefore 1.5%, while the hole density of the inner region 18b is 7.9%. The hole density of the entire hole pattern is 3.1%. The hole density of the hole pattern 14b decreases significantly from the inner portion 18b of the hole pattern 14b to the outer portion 20b of the hole pattern 14b. The ratio of the hole density in the inner region 18b to the hole density in the outer region 20b is 5.3.

FIG. 7 shows an inventive abrasive article 10c in the form of a circular grinding wheel. The abrasive article 10c has a diameter of 15 cm. The abrasive article 10c has a plurality of holes 12c for sucking off abrasive dust from a work surface 202 during a grinding process on the work surface 202. The plurality of holes 12c are arranged in a hole pattern 14c, with the hole pattern 14c covering the entire abrasive article 10c - ie, a narrow, negligible edge distance (the envelope of the hole pattern, ie a circle including the hole pattern, has a radius of more than 0.95 ^χ Overshoot - consequently the hole pattern covers more than 90% of the grinding wheel and thus essentially the entire grinding wheel). The hole pattern 14c also represents a symmetrical hole pattern 14c, in particular a rotationally symmetrical (eightfold symmetry) hole pattern 14c. The hole pattern 14c describes sixteen spiral lines 46 along which a plurality of the holes 12c of the hole pattern 14c are arranged. Four circular holes 13c are arranged along eight spiral lines 46, while four slots 38c are arranged along four other spiral lines 46. In this case, the spiral lines 46 extend in a circumferential direction (counterclockwise in this case), with a spiral line 46, along which in each case four circular holes 13c are arranged, alternately a spiral line 46 follows, are arranged along the four slots 38c. The respective elongated holes 38c are arranged aligned along a respective spiral line 46 such that an axis 50 defined by the elongation of the slot 38c extends substantially tangentially to the spiral line 46. In the center 22c, the hole pattern 14c has a center hole 44c having a diameter of 10 mm (area 78.5 mm ² ). The spiral lines 46 are formed such that a tangent to the spiral line represents, as it were, a tangent to the center hole 44c. Further, the spiral lines 46 are surrounded by a circle 48 of holes 12c, the circle 48 consisting of an eightfold repetition of the combination "circular hole 13c - slot 38c - slot 38c".

The elongated holes 38c have a radius η_ι_ of 1.05 mm and a length LL of 5.25 mm. The oblong holes have a total surface area of 480 mm ² . The circular holes 13c have a radius n_ of about 1.5 mm and form a total surface area of 226 mm ² . The hole pattern 14c has in the inner region 18c on a pinhole area of Aunnen = 4.0 cm ^2, while the outer region 20c = having a hole area of AI_ outer 3.8 cm ^2. The hole density of the outer region 20c is therefore 2.9%, while the hole density of the inner region 18c is 9.1%. The hole density of the entire hole pattern is 4.4%. The hole density of the hole pattern 14c decreases significantly from the inner portion 18c of the hole pattern 14c to the outer portion 20c of the hole pattern 14c. The ratio of the hole density in the inner region 18c to the hole density in the outer region 20c is 3.1.

FIG. 8 shows a slightly modified embodiment of the abrasive article 10b shown in FIG. The abrasive article 10d is also realized in the form of a circular grinding wheel and has a diameter of 15 cm. The abrasive article 10d has a plurality of holes 12d for sucking off abrasive dust from a work surface 202 during a grinding process on the work surface 202. The plurality of holes 12d are arranged in a hole pattern 14d with the hole pattern 14d covering the entire abrasive article 10d - ie, a narrow, negligible edge distance (the envelope of the hole pattern, ie a circle including the hole pattern, has a radius of more than 0.98 Rausen on - hence the hole pattern covers more than 96% of the grinding wheel and thus essentially the entire grinding wheel). The hole pattern 14d also describes eight spiral lines 46 along which holes 12d of the hole pattern 14d are arranged. The hole pattern 14d likewise has, in the inner region 18d, twenty-four holes 12d formed as a slot 38d, which are arranged along the spiral lines 46.

In this case, the spiral lines 46 extend in a common direction of rotation (here counterclockwise). Per spiral line 46, three elongated holes are arranged along the corresponding spiral line 46. The respective elongated holes 38d are arranged aligned along a respective spiral line 46 such that an axis 50 defined by the elongation of the slot 38d extends substantially tangentially to the spiral line 46. In the center 22d, the hole pattern 14d has a center hole 44d having a diameter of 10 mm (area 78.5 mm ² ). The spiral lines 46 are formed such that a tangent to the spiral line represents, as it were, a tangent to the center hole 44d. The elongated members 38d have a radius η_ι_ of 1.05 mm and a length LL of 5.25 mm. The slots have an area of 240 mm ² in total.

Further, each spiral line 46 four further circular holes 13d along the respective spiral line 46 are arranged, wherein the three outer circular holes 13d are in the outer region 20d of the abrasive article 10d and a circular hole 13d is still located in each case in the inner region 18d. The circular holes 13d have a radius n_ of about 1.5 mm.

The hole pattern 14d thus has a hole area of Ai_-inside = 3.5 cm ² in the inner area 18d, while the outer area 20d has a hole area of Ai_-outer = 2.0 cm ² . The hole density of the outer region 20d is therefore 1.5%, while the hole density of the inner region 18d is 7.9%. The hole density of the entire hole pattern is 3.1%. The hole density of the hole pattern 14d decreases significantly from the inner area 18d of the hole pattern 14d to the outer area 20d of the hole pattern 14d. The ratio of the hole density in the inner region 18d to

Outdoor hole density 20d is 5.3.

In contrast to the hole pattern 14d shown in FIG. 6, the holes 12d in this exemplary embodiment have different distances along a respective spiral line 46, compared with the distances of the holes 12d along one The hole pattern 14d here therefore represents an asymmetrical, in particular rotationally symmetric, rotational asymmetric, axis asymmetric, point asymmetric and translational asymmetric, hole pattern 14d. Due to the asymmetrical distribution of the hole pattern 14d, the advantageous effects of particularly good suction are further enhanced.

It should be noted once again that the abrasive article can also be realized in the form of an abrasive belt, a sanding sheet, a sanding strip or another form of clothing that appears meaningful to a person skilled in the art. Furthermore, the embodiments do not imply limitation to a grinding wheel with a diameter of 15 cm.

Claims

claims

An abrasive article (10a, 10b, 10c, 10d), in particular a coated abrasive disc, having a plurality of holes (12a, 12b, 12c, 12d) arranged in a hole pattern (14a, 14b, 14c, 14d), one Hole density from an inner portion (18a, 18b, 18c, 18d) of the hole pattern (14a, 14b, 14c, 14d) to an outer portion (20a, 20b, 20c, 20d) of the hole pattern (14a, 14b, 14c, 14d) decreases thereby characterized in that at least one hole (12a, 12b, 12c, 12d) in the hole pattern (14a, 14b, 14c, 14d) is formed as a slot (38a, 38b, 38c, 38d).

2. abrasive article (10a, 10b, 10c, 10d) according to claim 1, characterized in that a hole density in an inner region (18a, 18b, 18c, 18d) of the hole pattern (14a, 14b, 14c, 14d) between 7.5% and 16.0%, preferably between 8.5% and 13.0%, more preferably between 9.0% and 12.0%.

3. abrasive article (10a, 10b, 10c, 10d) according to any one of the preceding claims, characterized in that a hole density in an outer region (20a, 20b, 20c, 20d) of the hole pattern (14a, 14b, 14c, 14d) between 1, 5% and 4.8%, preferably between 2.0% and 3.8%, more preferably between 2.9% and 3.4%.

4. abrasive article (10a, 10b, 10c, 10d) according to any one of the preceding claims, characterized in that a ratio of the hole density in an inner region (18a, 18b, 18c, 18d) to the hole density in an outer region (20a, 20b, 20c, 20d) is between 1.9% and 6.9%, preferably between 2.8% and 6.0%, particularly preferably between 3.1% and 5.7%.

5. abrasive article (10a, 10b, 10c, 10d) according to any one of the preceding claims, characterized in that a hole density of the entire hole pattern (14a, 14b, 14c, 14d) between 2.6% and 6.8%, preferably between 3 , 0% and 6.5%, more preferably between 3.5% and 5.5%.

Abrasive article (10a, 10b, 10c, 10d) according to one of the preceding claims, characterized in that the number of oblong holes (38a, 38b, 38c, 38d) in an inner region (18a, 18b, 18c, 18d) of the hole pattern (14a, 14b, 14c, 14d) is greater than the number of elongated holes (38a, 38b, 38c, 38d) in an outer region (20a, 20b, 20c, 20d) of the hole pattern (114 _> 14a, 14b _> 14c _> 14d).

Abrasive article (10a, 10b, 10c, 10d) according to any one of the preceding claims, characterized in that an elongation and / or a radius of a first elongated hole (38a, 38b, 38c, 38d), in particular a long hole (38a, 38b, 38c, 38d) in the inner region (18a, 18b, 18c, 18d) of the hole pattern (14a, 14b, 14c, 14d) are / is different from an elongation and / or a radius of a second oblong hole (38a, 38b, 38c, 38d), in particular a long hole (38a, 38b, 38c, 38d) in the outer region (20a, 20b, 20c, 20d) of the hole pattern (14a, 14b, 14c, 14d).

Abrasive article (10a, 10b, 10c, 10d) according to one of the preceding claims, characterized in that the hole pattern (14a, 14b, 14c, 14d) a symmetrical hole pattern (14a, 14b, 14c, 14d), in particular a rotationally symmetric and / or is rotationally symmetric and / or axisymmetric and / or point symmetric and / or translationally symmetric hole pattern (14a, 14b, 14c, 14d).

Abrasive article (10a, 10b, 10c, 10d) according to any one of claims 1-7, characterized in that the hole pattern (14a, 14b, 14c, 14d) has an asymmetrical hole pattern (14a, 14b, 14c, 14d), in particular a rotationally asymmetric and / or Drehasymmetrisches and / or axis asymmetric and / or puncture-symmetric and / or translation asymmetric hole pattern (14a, 14b, 14c, 14d), is.

0. The abrasive article (10a, 10b, 10c, 10d) according to any one of the preceding claims, characterized in that the hole pattern (14a, 14b, 14c, 14d) at least one spiral line (46), preferably a plurality of spiral lines (46) describes , along the holes (12a, 12b, 12c, 12d) of the hole pattern (14a, 14b, 14c, 14d) are arranged.

1 1. Abrasive article (10a, 10b, 10c, 10d) according to claim 10, characterized in that in each case at least one slot (38a, 38b, 38c, 38d), preferably in each case at least two elongated holes (38a, 38b, 38c, 38d), particularly preferably in each case at least three elongated holes (38a, 38b, 38c, 38d) are arranged along a spiral line (46).

12. An abrasive article (10a, 10b, 10c, 10d) according to any one of claims 10-1, characterized in that a respective elongated hole (38a, 38b, 38c, 38d) is arranged aligned along a spiral line (46) such that a axis defined by the elongation of the slot (38a, 38b, 38c, 38d) is substantially tangential to the spiral line (46).

The abrasive article (10a, 10b, 10c, 10d) of any one of claims 10-12, characterized in that the hole pattern (14a, 14b, 14c, 14d) has a center hole (44a, 44b, 44c, 44d), one Tangent to the center hole (44a, 44b, 44c, 44d) as it were a tangent to the at least one spiral line (46) forms and / or wherein each tangent to the center hole (44a, 44b, 44c, 44d) as it were a tangent to each one forms the plurality of spiral lines (46).