EP2641696B1 - Tool for processing materials - Google Patents

Description

The invention relates to a tool for processing materials, preferably a grinding wheel, with a carrier body, wherein the tool has a hub for receiving a drive shaft.

Such tools for processing materials are known in the art. The DE 298 19 006 U shows a tool with a support body, which has receiving slots on the circumference in a partially radial direction, are inserted into the diamond and, for example, held by a metallic coating. The US 4,004,378 shows a grinding wheel whose rotationally symmetrical support body is provided on its peripheral surface with an abrasive coating. The carrier body also has feedthroughs for achieving a substantially parallel to the axis of rotation of the carrier body extending air flow. Furthermore, the disclosed DE 42 43 480 A1 a tool according to the preamble of claim 1.

In the known in the prior art tools is disadvantageous that especially for grinding wheels with relatively large thicknesses D, the carrier body are heavy and thus unwieldy, and vibrations of the carrier body in use are often difficult to predict and control.

The vibration damping known carrier body for suppressing vibrations during grinding operation is therefore often in the prior art in the form that the support body of the tool is made of a material which allows slight compression due to its material properties, such as a plastic or elastomer with a high degree of hardness. In this case, however, material inhomogeneities of the solid material forming the carrier body can lead to uneven damping behavior and thus to defects in the processing result. In addition, as far as possible, even by the use of such materials, the problem of considerable unwieldiness of grinding wheels with large thicknesses D, as used for example in centerless grinding, not overcome.

Currently, for the production of lightweight grinding wheels usually solid support body made of light metal, such as aluminum, or, if further weight reduction is necessary, also used from carbon fiber composites. However, the production of such carrier body made of carbon fiber composites very expensive and expensive. The mechanical properties, in particular with regard to a possible radial elasticity of the carrier body are hardly controllable in the known carrier bodies.

The present invention is therefore based on the object to provide a tool for processing materials of the type mentioned above, which overcomes the disadvantages of the prior art and in particular by ease of handling, especially with large thicknesses D, and improved suppression characterized by vibrations in grinding operation.

According to the invention, the above object is achieved by a tool for processing materials having the features of patent claim 1. Preferred embodiments are subject of the dependent claims.

Thereafter, the tool in question for processing materials, in particular a grinding wheel, with respect to a rotation axis substantially cylindrically symmetrical outer geometry, with an inner hub or axle receiving through the center of which the axis of rotation extends centrally, a concentric to this, outer shell body whose Peripheral surface is provided with an abrasive coating, and arranged between the hub and the jacket body support body, which is preferably integral with the hub and / or the jacket body. In this case, the jacket body has an averaged outer radius R _A and a thickness D which corresponds to the cylinder length of the jacket body and preferably also to the thickness of the carrier body.

According to the invention, the carrier body is configured with at least two feedthroughs arranged symmetrically about the axis of rotation within each section plane which extends in the direction of the outer edge of the carrier body from the inner region of the carrier body, ie from the edge region of the carrier body lying at the hub. So to the jacket body. In each sectional plane of the carrier body, the ratio A _D / A _T of the sum of the areas forming the passages A _D and the surface A _T forming the carrier body material is greater than 1, preferably greater than 2, preferably greater than 3 and preferably greater than 4 , that is, the areas forming the passages A _D in their sum greater than the surface of the material forming the support body A _T , and preferably significantly larger.

In accordance with the invention, it has been recognized that, in order to improve the processing result of products manufactured using generic tools, both a reduction in weight and improved damping properties or a reduced vibration behavior of the tools considerably contribute. With regard to the optimum machining result to be achieved, in particular a targeted vibration damping behavior of the carrier body during grinding is required in order to avoid the formation of vibrations.

This is achieved by a targeted geometric design of the tools according to the invention, which is reflected equally in the weight of the tool and in its radial elasticity. By determining the number and specific geometric configuration of the bushings of the carrier body, which can be modified even after the completion of the tool in certain areas, namely thereby the bushings are changed or increased in shape, is an exact adjustment of the mechanical properties and parameters the tools of the invention in particular in terms of weight and radial elasticity or compression capability possible. As a result, the radial elasticity of the tool and thus its damping is increased, so that any machine or drive vibrations can be better absorbed.

The elasticity and the weight of a tool according to the invention are in this case in particular by means of the width, the radial extent and optionally the curvature of the bushings of the carrier body adjustable. The greater the ratio A _D / A _T from the areas forming the passages A _D and the surfaces forming the carrier body material A _T , the lighter the tool according to the invention will be on the one hand and on the other hand simultaneously decrease the stiffness of the support body and its radial elasticity and thus Be increased vibration damping behavior.

The reduced weight of the tools according to the invention also leads to better handling of the tools according to the invention and makes it possible, for example, to simplify the drives of the machines according to the invention using the machines, since the driven Masses are significantly reduced and thus the complexity of the drives or drive components can be reduced. The reduction of the moving masses also allows a simplified vibration damping within the drive train and the tool guides, whether this is active or passive.

The carrier body according to the invention can be made of a variety of materials, such as steel, aluminum, copper, bronze or the like, since the vibration is not carried out by the material properties themselves, but by the geometric configuration of the bushings of the carrier body. Thus, both a significant weight reduction can be achieved as a targeted vibration damping, especially in metallic support bodies, which have almost no radial elasticity in support bodies of solid material or support bodies with bushings of small geometric dimensions.

Particularly preferably, the tool according to the invention has a geometry which is characterized by a ratio D / R _A of thickness D and average outer radius R _{A of} the sheath body between 0.015 inclusive and 2.5 inclusive, preferably by a ratio between 0.03 inclusive and 1 , 6 inclusive, more preferably between 0.05 inclusive and 1 inclusive, and more preferably between 0.08 and 0.8. It should be noted that the thickness D of the tool can also result from the precise assembly of a plurality of tools according to the invention of smaller thickness, so that the composite has a quasi-continuous and one-piece shell surface with a corresponding abrasive coating.

The sizes which are most preferably used in the context of the above ratios are thicknesses D between 10 mm inclusive and 600 mm inclusive and radii R _A between 75 mm inclusive and 350 mm inclusive.

Hereinafter, shows that in particular those tools of the inventive embodiment benefits which have, depending on the diameter, a certain minimum thickness D _min, which are for tools with radii R _A of 75mm at about 1 0mm and for tools with radii R _A of 75mm at about 20mm. These tools experience by the inventive design with significant reduction in their weight, which eventually leads to the reduction of unwanted moments, essentially no unwanted loss of their stability, especially their Deformability in the transverse direction so parallel to the axis of rotation, although a targeted and advantageous for the operation of the tools radial elasticity can be brought about, even when using particularly hard and inherently inelastic materials for the preparation of the carrier body.

In one embodiment of the invention, an odd number of feedthroughs are provided for optimizing the vibration behavior, as this, in conjunction with the intended speed, can lead to reduced resonant tooling.

In one embodiment of the invention, the bushings are designed in the form of quadrilaterals in their base area, wherein the long sides are preferably connected in a radially extending manner to the short sides, and the short sides are arranged on the inner or outer region of the carrier body. Although a straight course of the long sides of the bushings is preferred but not required. Likewise, a rounded design of the inner corners of the squares is preferred so that sharp-edged inner corners are present at the bushings.

In a development, at least one of the short sides in the plan view, that is to say when viewing a cutting plane arranged normally by the carrier body, can be at least partially circular-segment-shaped, for example concentric with the outer circumference of the lateral surface. Preferably, the two long sides of the respective bushing are designed to be of equal length, so that the bushings of the carrier body in this embodiment of the invention appear substantially annular segment-shaped.

However, it is also possible that at least one of the short sides, preferably the inner of the two short sides is made so short that it is composed only of two merge radii running together, especially in the choice of large radii of connection, and thus under a square-like according to the invention Form in plan view also falls a substantially delta-shaped design in which two corners of the quadrangular shape substantially coincide.

This embodiment of the grinding tool according to the invention is referred to as spoke segment disc, in particular when a plurality of bushings are provided, for example 12, since the material remaining between the bushings is designed like a spoke is, wherein the spokes preferably have a thickness in the direction of the axis of rotation, which have substantially the entire material thickness of the support body, and the corresponding, preferably also of the shell body. Such an embodiment is extremely stable despite a very low weight.

To further improve the vibration damping properties of the tool according to the invention in a preferred embodiment of the invention, the quadrangular passages are distorted or bent around a point located outside the respective implementation, so that the long sides of the bushings in plan view are substantially arcuate or preferably circular segment. The resulting from the remaining between adjacent passages material of this embodiment of the invention spokes are thus arcuately curved and preferably circularly curved and extend in the interior of the carrier body, ie substantially from the hub or axle initially substantially radially outward, then, by the curvature of which is a kind of asymptotic approach towards the periphery of the tool. The degree or extent of the approach of the spokes to the circumference of the tool is different selectable and, as it were, an essential parameter for the radial elasticity of the tool.

Preferably, the long sides of adjacent bushings are substantially parallel, and this applies equally to substantially radially extending long sides of the bushings as well as curved or even circular segment running. Nevertheless, for example, those embodiments are preferred within the scope of the invention, in which a tapering of the spokes is carried out towards the outer region of the carrier body by a non-parallel course of the long sides of passages, whereby further influencing the radial elasticity and the weight of the tools according to the invention this Embodiment can be achieved.

Particularly preferably, the longer of the short sides is arranged in the outer region of the carrier body, that is arranged close to or even adjacent to the jacket body and the shorter of the short sides in the inner region of the carrier body, ie near the hub or axle fitting or adjacent thereto.

In a further embodiment of the invention, to achieve a particularly good vibration damping, the bushings of the carrier body from its opposite cylindrical top surfaces are incorporated substantially up to its center in the material of the carrier body, for example by milling. It is particularly advantageous, the bushings, which are incorporated from the second side, so for example, the upper cylinder top surface of the carrier body ago by a predetermined rotation angle α about the axis of rotation rotates with respect to those of the first side of the carrier body, so for example the lower cylinder top surface will be incorporated to rotate. As a result, the spokes between adjacent feedthroughs of one side of the carrier body are thus substantially not congruent with the spokes between adjacent feedthroughs of the other side of the carrier body.

Preferred angles of rotation α lie between 0 ° and 90 °, in each case inclusive, preferably between 30 ° and 60 °, preferably at 45 °, and particularly preferably at half the angular pitch of the bushings, ie at an angle α = 360 ° / (2n ), where n is the number of feedthroughs in a plane normal to the axis of rotation.

It is preferred to reduce and at best to prevent imbalance of the tool according to the invention in its use could be provided in the carrier and / or sheath body at least one, as required, several balancing bores. Furthermore, embodiments of the invention are also provided in which the thickness of the carrier body (in the direction of the axis of rotation) is smaller, that is, the thickness D of the jacket body, so that the carrier body so arranged in relation to the jacket body or the cylinder top surfaces defined by this receding is.

Preferably, the abrasive coating is applied by gluing or sintering or similar known methods on the outer peripheral surface of the sheath body and preferably selected from a group of diamond needles such as PCD, MKD, CVD, CBN needles, metal, plastic or ceramic bonded Diamonds, metal or plastic bonded boron nitride, in particular cubic boron nitride.

Fig. 1

in einer schematischen Ansicht, eine Draufsicht auf ein erstes Ausführungsbeispiel eines erfindungsgemäßen Werkzeugs;

Fig. 2

in einer schematischen Ansicht, eine Draufsicht auf ein zweiten Ausführungsbeispiel eines erfindungsgemäßen Werkzeugs, wobei dieses eine Abwandlung des erstens Ausführungsbeispiels mit versetzten Durchführungen zeigt;

Fig. 3

in einer schematischen, perspektivischen Ansicht, das zweite Ausführungsbeispiel gemäß Fig. 2;

Fig. 4

in einer schematischen Ansicht, eine Draufsicht auf ein drittes Ausführungsbeispiel eines erfindungsgemäßen Werkzeugs,

Fig. 5

in einer schematischen, perspektivischen Ansicht, das vierte Ausführungsbeispiel gemäß Fig. 4.

Further features of the present invention will become apparent from the following description of preferred embodiments of the tool according to the invention in conjunction with the drawings. It shows:

Fig. 1

in a schematic view, a plan view of a first embodiment of a tool according to the invention;

Fig. 2

in a schematic view, a plan view of a second embodiment of a tool according to the invention, this shows a modification of the first embodiment with offset feedthroughs;

Fig. 3

in a schematic, perspective view, the second embodiment according to Fig. 2 ;

Fig. 4

in a schematic view, a plan view of a third embodiment of a tool according to the invention,

Fig. 5

in a schematic, perspective view, the fourth embodiment according to Fig. 4 ,

The Fig. 1 to 5 show grinding wheels according to the present invention. The grinding wheel according to Fig. 1 has a centrally arranged hub or receptacle A for a - not shown - shaft of a machine tool, a sheath body 4 and arranged on the outer circumference of the sheath body 4 abrasive coating B with preferred thicknesses between 2mm and 30mm. Between receiving A and 4 sheath body, a support body 1 is arranged, this being made in one piece with the receptacle and the sheath body of a light metal, such as aluminum. The sheath body and preferably also the carrier body have a thickness D and the grinding wheel is substantially cylindrically symmetrical with respect to the axis of rotation R, with the exception of the feedthroughs 2 arranged inside the carrier body 1. The outer radius of the grinding wheel is R _A.

In accordance with the invention, the carrier body 1 has a plurality of bushings 2, wherein the bushings 2 extend from the inner region 1 'of the carrier body, namely from the region of the receptacle A, in the direction of the outer region 1 "of the carrier body 1, and the present ring segment-shaped are formed with long sides 2 ', which are substantially radially and are of equal length, and short sides 2 ", which extend substantially concentrically with respect to the axis of rotation R, in which case a straight-line design of the short sides 2" into consideration comes. The remaining between adjacent passages 2 material areas are designed in the manner of spokes 3, which in the present case extend radially and whose strength increases due to the radial course of the long sides 2 'to the outside. In the outer region of the jacket body a balancing bore W can be seen.

As it turned out Fig. 1 can recognize, a total of 10 bushings are provided here, which are arranged uniformly around the axis of rotation in the carrier body 1.

This in Fig. 2 and 3 shown second embodiment is derived from the embodiment of Fig. 1 from, in which case the bushings 2 coming from the two cylinder top surfaces of the grinding wheel coming forth are introduced up to half the thickness of the carrier body 1. Accordingly, it can be seen that the spokes 3 of the material regions of the carrier body 1 which have remained standing between adjacent feedthroughs 2 on the side of the observer Fig. 2 (Front) are formed, whereas the spokes 3 'of the remaining between adjacent passages 2 material areas of the support body 1 on the opposite side of the viewer Fig. 2 (so to speak, the back) are formed. Further, the bushings 2 of the front to the bushings 2 of the back are rotated by an angle α of 19 ° to each other.

In the in Fig. 4 and 5 shown third embodiment of the present invention have the same reference numerals as in Fig. 1 Structurally and functionally similar elements, so that reference is made to the above. However, in this embodiment, in order to improve the radial elasticity of the tool, the bushings 2 are distorted around a point located outside the respective bushing 2, so that the long sides 2 'in this embodiment are circular-segment-shaped and also have the same radius, which but not required. In an alternative embodiment of the invention, the long sides 2 'of the bushings 2 can be designed such that the thickness of the spokes 3 between two adjacent bushings 2 extends substantially uniformly from the inner region 1' of the carrier body to its outer region 1 ''.

The short sides 2 "are connected by radii with the long sides 2 ', wherein here a maximum extent up to the shell body 4 is exploited.In addition, the long side 2' are designed so that these, if they are on the shell body However, this is likewise not necessary and, depending on the application and the radial elasticity to be generated, an asymptotic approach to the inner edge of the sheath body may also be made or at a shallow angle thereto tapered shape are preferred, as can be seen in Fig. 4 the case is.

As in Fig. 4 It can also be seen that the long sides 2 'also extend substantially radially away from the inner region 1' of the carrier body 1 or the receptacle A, so that the spokes 3 also have such a shape, that is to say initially radially away from the receptacle A. extend to the outside then following the curvature at a shallow angle in the outer region 1 "of the carrier body to be substantially auflieaufen on the jacket body.

With reference to the Fig. 5 In addition, it can be seen that the present invention is particularly suitable for use in conjunction with tools of large thicknesses D, since on the one hand the considerable reduction in weight leads to simplified handling and likewise the radial elasticity brought about by the special embodiment of the tools according to the invention leads to a significantly improved vibration behavior. Fig. 5 also shows that the carrier body is slightly offset with respect to the sheath body, which results from a reduced in the direction of the rotation axis R material thickness of the carrier body compared to the thickness D of the sheath body.

For further details reference is made to avoid repetition to the general description. Finally, it should be noted that the features described in the preceding embodiments, in the general description can be combined in such a way that they do not go beyond the scope of the subject-matter defined by the following claims.

Claims (11)

1. A tool for processing materlals, in particular an abrasive wheel having an outer geometry which is substantially cylindrically symmetrical relative to a rotational axis (R), an internal hub (A) through the center of which the rotational axis extends centrically, an external shell body (4) concentric therewith, the circumferential surface of which is provided with an abrasive coating (B), and at least one carrier body (1) disposed between the hub and the shell body, which carrier body preferably is integral with the hub (A) and/or the shell body, the shell body having a mean outer radius R_A and a thickness D, the carrier body (1) being configured with at least two apertures (2) which are located symmetrically about the rotational axis within each sectional plane which is normal to the rotational axis (R), which apertures extend from the inner portion (1') of the carrier body, i.e. from the peripheral portion of the carrier body located near the hub (A), towards the outer edge (1") of the carrier body, i.e. towards the shell body (4), said tool being characterized in that, in each sectional plane of the carrier body, the ratio A_D/A_T of the surface A_D forming the apertures (2) and the surface A_T forming the carrier body material is ≥ 1.
2. The tool of claim 1, characterized in that the ratio of A_D/A_T is a 2, preferably a 3, and preferably ≥ 4.
3. The tool of claim 1 or claim 2, characterized in that the tool has a ratio D/R_A of the thickness D and the mean outer radius R_A of the shell body (4) between, inclusively, 0.015 and, inclusively, 2.5; preferably a ratio between, inclusively, 0.03 and, inclusively,1.6; more preferably a ratio between, inclusively, 0.05 and, inclusively, 1; and more preferably a ratio between 0.08 and 0.8.
4. The tool of any of claims 1 to 3, characterized in that an odd number of apertures (2) is provided.
5. The tool of any of claims 1 to 4, characterized in that the basic areas of the apertures (2) have a quadrangular configuration.
6. The tool of claim 5, characterized in that the long sides (2') of the apertures (2) are preferably radially connected to the short sides (2") of the apertures (2), and/or one or both short sides (2") extend in the shape of a segment of a circle which is preferably concentric about the rotational axis (R).
7. The tool of any of claims 1 to 5, characterized in that the apertures (2) are distorted or curved about a point located, respectively, outside the aperture (2) in the sectional plane, so that the long sides (2') extend arcuately, preferably circularly, towards the outer edge (1") of the carrier body (1).
8. The tool of any of claims 1 to 7, characterized in that the material portions of the carrier body (1) which are formed between adjacent apertures (2) form spokes (3), the thickness of the spokes (3) preferably being substantially equal from the inner portion (1') to the outer edge (1").
9. The tool of claim 8, characterized in that the spokes (3) within the sectional plane extend in a shape continuously approaching the outline of the shell body (4), preferably a curved shape approaching asymptotically at least in part.
10. The tool of any of claims 1 to 9, characterized in that apertures (2) extend from the opposing cylinder coversurfaces of the carrier body (1) into the same to half a thickness of the carrier body (1), and the apertures (2) extending from the first cylinder cover surface are twisted relative to the apertures (2) extending from the second cylinder cover surface by a rotational angle α of between 0° and 90°, preferably between 30° and 60°, preferably 45°, and particularly preferably by an angle α = 360°/(2n), n being the number of apertures in a sectional plane.
11. The tool of any of claims 1 to 10, characterized in that at least one balancing hole (W) is provided in the carrier body (1) and/or in the shell body (4).

Images