Patent Application
20100190419
Priority is claimed to German Patent Application No. DE 10 2008 063 943.5, filed Dec. 19, 2008, the entire disclosure of which is incorporated by reference herein.
The invention relates to a tool for the surface machining of workpieces, comprising a drive for acting upon a spindle that is connected to the drive, on which spindle the tool is detachably fixed to the spindle.
In the case of production by means of parting with the use of a geometrically indefinite cutting edge, with the use of a rotating tool, there are basically two main applications, namely, the axial and the radial application. For these applications, there is a multiplicity of tools, particularly stock-removing tools. These tools differ in their configurations, their shape and their granularity. The machining tools are designed on the basis of the boundary conditions for the respective machining purpose in respect of size, material to be machined and machining speed.
A shaft, preferably made of steel, a core or basic body, and individual abrasive laminae are usually provided as main component parts of an axially acting stock-removing tool. The shaft in this case has a standardized diameter, and is clamped in a matched tool holder. The core serves to fix and support the individual abrasive laminae. The number, granularity and shape of the abrasive laminae depends on the intended purpose. The individual abrasive laminae are arranged axially on the core, i.e. their working surface is aligned in the axial direction. The choice of the granularity of the individual abrasive laminae is determined, in essence, according to the material to be machined, according to the required removal of material and according to the required quality of the workpiece surface to be produced.
A spindle drive produces a rotatary motion that drives the so-termed axial stock-removing tool. The rotational speed required is dependent on various factors, such as, for example, the diameter of the tool, the material to be machined or the required surface quality.
In the case of the axial stock-removing tool, the machining surface is located on the underside of the stock-removing tool, i.e. the axis of the abrasive tool is perpendicular to the surface to be machined.
A radially acting machining tool likewise consists of a shaft, preferably made of steel, and of a stock-removing body, which, as a rotationally symmetrical body, for example in the form of a cylinder, is provided with peripherally arranged chip-producing formed-on elements. Instead of that, it can also be constituted by individual, radially projecting abrasive laminae that are centrally connected to one another. The shaft, with its likewise standardized diameter, is clamped in a matched tool holder. The chip-producing formed-on elements on the stock-removing body can either be of the same material as the stock-removing body or be composed of special material, for example hard metal or corundum (Al2O3) or diamond.
In the case of chip production through removal of stock by means of abrasion, the granularity of the individual abrasive laminae, or abrasive bodies, is determined substantially according to the material to be machined, according to the required removal of material and according to the required surface quality of the respective workpiece.
Here, likewise, the rotatory motion of the so-termed radial stock-removing tool is produced through a spindle drive. The rotational speed required is dependent on various factors, such as, for example, the diameter of the tool, the material to be machined or the required surface quality.
In the case of the radial stock-removing tool, the machining surface is located on the circumference of the tool, i.e. the abrasive tool and the surface to be machined are arranged parallel to one another.
An aspect of the present invention is to create a tool, of the type mentioned at the outset, that, in the simplest manner possible, offers the possibility whereby more than one surface region of the workpiece can be machined simultaneously by means of a single tool.
Accordingly, the tool is provided with at least two working surfaces, which are intended for simultaneous action upon the respective workpiece, namely, at least one working surface acting in the axial direction and at least one working surface acting in the radial direction.
The shaft provided for connecting the tool according to the invention to the spindle is preferably composed of metal. For particular applications, however, it may be advantageous for the shaft to be made of non-metallic material, for example of plastics or ceramic, and to be fibre-reinforced if appropriate.
According to a preferred embodiment of the tool according to the invention, the tool serves the purpose of stock-removing or chip-producing machining the respective workpiece. It proves to be advantageous in this case for the tool to have working surfaces that project radially and/or axially from the spindle axis.
According to a further advantageous embodiment variant, the tool according to the invention can have at least one working surface inclined at an angle of <90° in relation to the spindle axis, which working surface is provided either in addition to one of the aforementioned working surfaces or together with the two aforementioned working surfaces.
A further advantageous embodiment variant of the invention can be achieved in that the tool has at least two surface regions, which are inclined differently in relation to the spindle axis.
A further aspect of the invention relates to the drive of the tool. This drive can be fully rotatory, and put into rotation the tool that is subject to the action of the drive, or it can be partially rotatory, i.e. the tool according to the invention is put into an oscillating rotation in which the rotary motion changes alternately to a contra-directional rotational direction according to the oscillation frequency.
The fully rotatory drive is commonplace, and is known, for example, from power drills. The drive designated as partially rotatory is also known per se, even if it is not as widespread as the fully rotatory drive. In particular, tools that are intended for a partially rotatory drive must be matched to the contra-directional rotational direction, in order to ensure accuracy of form and dimensions.
For the tools according to the invention, it is the case, in general, that the outer contour of the tool defined by the working surfaces is rotationally symmetrical.
Accordingly, provision is made, according to a preferred development of the invention, whereby the tool is a rotationally symmetrical milling body or sawing body. A sawing body in this case is understood to be a disc-shaped milling body of small thickness.
The direction of action of such a milling body is preferably the radial direction, but, in special cases, it can also be provided in the axial direction.
According to one embodiment, the milling tool according to the invention has at least one cutting edge, but preferably 3 or more cutting edges, the alignment of which runs in a plane that extends parallel and/or at right angles to the spindle axis. Alternatively, the alignment of the cutting edges can run in a plane inclined at an angle of <90° in relation to the spindle.
Further, the milling bodies according to the invention can be provided with rectilinear or curved cutting edges, the latter being able to have, preferably, a helical shape.
According to an alternative embodiment of the invention, the tool is constituted by centrally guided abrasive means that engage radially and/or axially, the abrasive means preferably being constituted by centrally guided abrasive laminae that engage radially and/or axially.
In a development of the invention, provision is made in this case whereby the tool provided with abrasive laminae has a shaft, a basic body arranged in a rotationally fixed manner thereon, and an abrasive lamina exchangeably fastened thereto, the shaft becoming operatively connected to the spindle and having an outer diameter provided according to the provided abrasive laminae.
According to another alternative of the invention, the tool is characterized in that it is constituted by a centrally guided abrasive body that engages radially and/or axially, this abrasive body having, respectively, a basic body whose surface is provided, respectively, with abrasive particles.
The outer contour of the respective abrasive body can preferably be matched to the contour to be produced on the workpiece.
According to an advantageous development of the invention, the abrasive particles present on the surface of each basic body are intimately connected to the respective basic body.
Preferably, the abrasive particles present on the surface of each basic body are provided in differing granularities, i.e., according to the invention, separate abrasive bodies are provided for each granularity. Advantageously in this case, the granularity of the abrasive particles is matched, respectively, to the material of which the workpiece to be machined is composed.
Alternatively, however, provision can be made whereby an abrasive body is provided with abrasive particles of differing granularity and/or of differing material, for example predominantly with abrasive particles of corundum (Al2O3) and with a lesser proportion of diamond particles.
Further, determinant in the choice of the abrasive material provided for facing the abrasive bodies according to the invention is its density and arrangement, in addition to the nature of its granularity.
A metallic material, preferably, is possible as a substrate material for the abrasive means according to the invention. For particular applications, however, it may be advantageous for the substrate to be of non-metallic material, for example plastics or ceramic, and to be fibre-reinforced if appropriate.
As already mentioned above, an intimate connection of the abrasive particles to the substrate is provided according to the invention. Such an intimate connection, having sufficient mechanical stability, is preferably realized by means of adhesive, being an adhesive for metallic materials or for non-metallic materials. Preferably, according to the invention, multi-component adhesives are used for this purpose.
A further criterion for the effectiveness of the tool according to the invention is the field of application, i.e. the respective material of the workpiece to be machined, and the structural form of the tool, which is determined substantially by the diameter or thickness of the tool, depending on whether it is a radial tool or an axial tool.
Further, the total length of the respective tool affects its durability, as well as its scope of application.
Finally, in the case of radial tools that operate with abrasive laminae, the number of provided abrasive laminae is determinant.
These and further advantageous developments and improvements of the invention constitute the subject-matter of the dependent claims.
The invention, advantageous developments and improvements of the invention and particular advantages of the invention are to be explained and described more fully with reference to an exemplary embodiment of the invention represented in the appended drawing, wherein:
Shown in
According to the invention, the abrasive laminae 18 described above are non-detachably connected to the shaft 12, which, for its part, can be introduced into a shaft receiver of a drive and can be fixed therein in a rotationally fixed manner, which shaft receiver, not shown in greater detail, is provided for this purpose.
Arranged beneath the radial abrasive body 16 shown in
The abrasive laminae 18 and the abrasive splines 22 are each covered with abrasive particles, not designated in greater detail, which are preferably fixed thereto by means of adhesive bonding.
While the thus coated abrasive splines 22 already have an abrasive effect, owing to their identifiably undulated or angular shape, the abrasive effect of the abrasive laminae 18 is due to their flexibility, i.e. to the flexibility of the peripheral regions of the abrasive laminae 18.
Upon being applied to the respective workpiece, each abrasive lamina 18 undergoes elastic bending, owing to the rotation imposed by the drive, not shown here, and owing to the contact force required for the machining operation, such that an approximately strip-wide region of the abrasive lamina surface is thus guided along the workpiece surface. The abrasive particles arranged on the surface of each abrasive lamina 18 thereby effect removal of material, which removal is determined by the machining duration, contact force and tool surface.
An example for a practical application for the tool 10 according to
In this case, the tool 10 according to the invention operates with a radial and an axial force component that act upon the abrasive body, provided as a tool 10, in such a way that this abrasive body effects the recess 26 through a resultant removal of material.
The height and length, as well as the diameter, of the radially effective radial abrasive body 16 are in this case matched both to the available drive, or to its drive power, and to the material of which the respective workpiece 24 is composed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 063 943.5 | Dec 2008 | DE | national |
