EP3894120A2

EP3894120A2 - Circular milling tool and circular milling method

Info

Publication number: EP3894120A2
Application number: EP19801192.6A
Authority: EP
Inventors: Bruno Teusch
Original assignee: Guehring KG
Current assignee: Guehring KG
Priority date: 2018-08-22
Filing date: 2019-08-13
Publication date: 2021-10-20
Also published as: DE102018214192A1; WO2020038505A2; WO2020038505A3; US20210245274A1

Description

Circular milling tool and circular milling process

description

The invention relates to a circular milling tool and a method for producing a micro-groove structure in the cylindrical surface of a bore in a particularly metallic workpiece, e.g. a cylinder bore in one

Combustion engine.

It is well known that tribologically highly stressed surfaces of bores in metallic workpieces, e.g. B. the piston surfaces of

Cylinder bores or the cylinder liners in an internal combustion engine, for example mechanically roughened with the aid of cutting tools, in order to obtain a good adhesive base for a surface layer to be applied in particular by thermal spraying.

For this purpose, for example, DE 10 2016 216 464 A1 proposes a circular milling tool with a rotary drive that can be driven about an axis of rotation

Tool base body and a plurality of circumferential cutting side milling cutters arranged axially staggered on the tool base body. Everyone

Side milling cutters comprise a plurality of ones arranged in series in the circumferential direction

Cutting elements, each of which forms a multi-tooth circumferential cutting edge, to which a cutting face or rake face is connected on the cutting direction side. The

The circumferential edges of each side milling cutter show the same filigree

Cutting profile which is defined by a plurality of cutting teeth which are arranged at equal axial distances and are of the same size, the dimensions of the cutting teeth (tooth width, tooth height) each being in the pm range, for example in the range from 100 to 200 pm.

Since the circumferential cutting edges of each side milling cutter are arranged axially at the same height and have the same cutting profile, they leave a cylindrical surface of a workpiece in a circular milling process

CONFIRMATION COPY Surface of a number of filigree cutting marks corresponding to the number of cutting teeth per circumferential cutting edge. The traces of the cut in the circumferential direction in series

arranged cutting elements result in the sum of a micro-groove structure with a groove profile corresponding to the cutting profile of the peripheral cutting edges, which is defined by a plurality of axially spaced, circular circumferential micro-grooves, the cross-sectional profile of a micro-groove, in particular the groove width measured in the axial direction, the tooth profile, i.e. the tooth width corresponds to a cutting tooth. In a separate drilling or milling process following the circular milling process, the inside diameter of the webs separating the micro-grooves from one another, i.e. the inner diameter of the micro-groove structure is enlarged to a predetermined nominal diameter by means of a separate boring or milling tool.

The circular milling tool proposed in DE 10 2016 216 464 A1 is distinguished by the fact that 360 ° circular milling of a cylindrical surface in FIG

A micro-groove structure can be reproducibly produced with a groove profile which is defined by a plurality of axially spaced, circular circumferential micro-grooves. However, diameter machining, i.e. the completion, the micro-groove structure, another drilling or milling process and an additional boring or milling tool in addition to the circular milling tool.

Furthermore, they are arranged in series in the circumferential direction

Cutting elements of a side milling cutter have the same cutting profile, as a result of which the chip width of the chips resulting from circular milling is equal to the tooth width of the cutting teeth or the groove width of the micro-groove grooves. Particularly in series production, chip clamping between the circular milling tool and the machined bore surface can easily occur. A

Chip clamping can result on the one hand in a reduced service life of the circumferential cutting edges, ie the cutting elements, of the circular milling tool due to a strong thermal and mechanical stress on the filigree cutting profiles and on the other hand jeopardize the desired reproducibility of the defined groove profile of the microstructure to be produced. Starting from DE 10 2016 216 464 A1, the invention therefore has the

The task of creating a circular milling tool for producing a micro-groove structure with a groove profile, which is defined by a plurality of axially spaced, circular circumferential micro-grooves, which allows more economical milling of a cylindrical bore surface, in particular in series production.

This object is achieved by a circular milling tool with the features of claim 1. Advantageous further developments and preferred embodiments are the subject of dependent claims.

A circular milling tool according to the invention is used to roughen the cylindrical surface of a bore in a particularly metallic workpiece, e.g. a cylinder bore in an internal combustion engine, by creating a micro-groove structure that has a groove profile that is defined by a plurality of axially spaced, circular circumferential micro-grooves. That defined

Groove profile of the micro-groove structure to be produced is also referred to below as the end profile. The dimensions of the micro grooves (the groove width measured in the axial direction and the groove depth of each micro groove measured in the radial direction) are each in the pm range, for example in the range from 100 to 400 pm.

Analogous to the circular milling tool proposed in DE 10 2016 216 464 A1, a circular milling tool according to the invention has a basic tool body which can be driven about an axis of rotation and which carries at least one circumferential cutting edge set, but preferably a plurality of axially staggered circumferential cutting edge sets, directly or indirectly. Each set of peripheral cutting edges comprises several, i.e. at least two cutting elements, which are arranged in a row in the rotational or circumferential direction and each form a circumferential cutting edge to which a cutting face or rake face is adjacent. Each circumferential cutting edge set thus has at least two circumferential cutting edges which comprise at least one first circumferential cutting edge and at least one second circumferential cutting edge. The multiple circumferential cutting edges each

Circumferential cutting edge sets are preferably distributed around the axis of rotation at the same angular pitch, ie at equal angular intervals. However, this is not absolutely necessary, so that the angular division of the peripheral cutting edges per peripheral cutting edge set can also be unequal. Taking into account the filigree micro-groove structure to be produced, the peripheral cutting edges each have a filigree one or

multi-tooth cutting profile. In the case of a multi-tooth cutting profile, the dimensions of the cutting teeth (the tooth width measured in the axial direction and the tooth height of each cutting tooth measured in the radial direction) are each in the pm range, for example in the range from 100 to 400 pm. In the case of a single-tooth cutting profile, the tooth height of the cutting tooth measured in the radial direction is in the pm range, for example in the range from 100 to 400 pm, while the width measured in the axial direction can be in the mm range, for example in the range from 2 to 50 mm ,

In contrast to that proposed in DE 10 2016 216 464 A1

In a circular milling tool according to the invention, circular milling tools each have the circumferential cutting edges arranged in series in the circumferential direction

Circumferential cutting edge set each a cutting profile that deviates from the defined groove profile of the micro-groove structure to be produced. On the other hand, in a circular milling tool according to the invention, those projected in the circumferential direction overlap

Cutting profiles or rake faces of the at least two peripheral cutting edges in the axial direction in such a way or to such an extent that they jointly defined that

Groove profile of the micro-groove structure to be produced, i.e. map the end profile. Here, “projected in the circumferential direction” is understood to mean that the cutting edge profiles of the at least two peripheral cutting edges are mapped on a common longitudinal cutting plane of the circular milling tool. In other words, an overlay of a longitudinal section of a first circumferential cutting edge with a longitudinal section of a second circumferential cutting edge (or an overlapping of longitudinal sections of the at least two circumferential cutting edges of the circumferential cutting edge set) forms a longitudinal section of a circumferential cutting edge, the cutting edge profile of which corresponds to the end profile.

According to the invention, the at least two peripheral cutting edges, ie the first peripheral cutting edge and the second peripheral cutting edge, can have different cutting edge profiles for each peripheral cutting edge set, each of which differ from the end profile. Due to unequal cutting edge profiles, the at least two circumferential cutting edges per circumferential cutting edge set leave unequal in a machined workpiece surface Cut marks. If the at least two peripheral cutting edges per peripheral cutting edge set are each multi-toothed, the unequal cutting edge profiles can be created

realize, for example, that the plurality of cutting teeth of a first peripheral cutting edge in the axial direction with an offset to the e.g. same plurality of cutting teeth of a second peripheral cutting edge are arranged. In this case, the cutting teeth of the first peripheral cutting edge and the second

Circumferential cutting edge with regard to its tooth profile (seen in the cutting direction), e.g. may be rectangular, trapezoidal or dovetail-shaped, their tooth width (measured in the axial direction, possibly maximum), their tooth height (measured in the radial direction) and / or their tooth pitch (measured in the axial direction) may be the same as or different from one another. The use of the same tooth profiles etc. contributes to economical production and an axially compact design of the peripheral cutting edges.

Unequal cutting profiles can be realized, for example, by using unequal, for example plate-shaped, cutting elements with regard to the tooth profile, the tooth width, the tooth height and / or the tooth pitch

Tool body are arranged axially on the same fleas. The dimension of a circumferential cutting edge set measured in the axial direction can thereby be at least substantially limited to the axial dimension of a circumferential cutting edge.

According to the first circumferential cutting edge and the second

Circumferential cutting edge but also have the same cutting edge profiles, provided that the first

Circumferential cutting edge is axially offset by an amount corresponding to the axial overlap with respect to the second peripheral cutting edge. Due to the fact that the peripheral cutting edges are filigree to produce a micro-groove structure

Have cutting edge profiles, the axial dimension of one increases

Circumferential cutting edge set only insignificant compared to the axial dimension of a peripheral cutting edge. The same cutting edge profiles can be used, for example

Realize the use of the same, for example plate-shaped, cutting elements which are axially offset from one another on the tool base body by an amount corresponding to the axial overlap. The use of the same cutting elements can help to keep manufacturing costs low. It is therefore only decisive that the cutting traces of the at least two left in a workpiece surface to be machined

Circumferential cutting edges per circumferential cutting edge set overlap one another in the manner or so far, i.e. add up to an overlap profile that the

Overlap profile corresponds to the end profile.

Since the first peripheral cutting edge and the second peripheral cutting edge are offset in time due to the angular spacing, i.e. one after the other, cut into a workpiece to be machined and one cutting track each that only part of the end profile, i.e. create a partial profile, the cutting load per peripheral cutting edge is lower than if the first and the second peripheral cutting edge would each produce the complete end profile. However, the row arrangement of the at least two circumferential cutting edges, each having a cutting profile different from the end profile, and the axial overlap of the cutting profiles projected in the circumferential direction of the at least two circumferential cutting edges mean that circular milling of a cylindrical workpiece surface (bore surface) results in the

Cut traces of the circumferential cutting edges left behind on the workpiece surface can be fully reproduced by a 360 ° circular milling movement of the circular milling tool.

The circular milling tool according to the invention therefore enables an economical milling operation suitable for series production for roughening a cylindrical bore surface. Because of a lower chip removal

Circumferential cutting edge than that proposed in DE 10 2016 216 464 A1

Circular milling tool, in particular due to the smaller width of the chips to be removed than the width of an end profile, i.e. the width of the grooves of the micro-groove structure to be produced, the risk of chip clamping is reduced and each circumferential cutting edge is subjected to less stress, which results in a higher stress

Tool life results.

In a preferred embodiment, the (at least one) comprises

Circumferential cutting edge set at least a first peripheral cutting edge, preferably several, in particular two, first peripheral cutting edges, and at least one second peripheral cutting edge, preferably several, in particular two, second

Circumferential cutting edges, each of which has a cutting profile, preferably the same, having a plurality of cutting teeth in the axial direction, i.e. have a multi-tooth cutting edge profile in the axial direction, i.e. a multi-toothed

Form circumferential cutting edge. Each of these multi-tooth peripheral cutting edges therefore has a cutting profile defined by the plurality of axially spaced cutting teeth.

As a result, when the at least one first peripheral cutting edge and the at least one second peripheral cutting edge are cut into a workpiece surface, a partial profile of the end profile can be generated which corresponds to the cutting profile of the respective peripheral cutting edge. According to the invention, an (axial) overlay of the partial profiles forms the end profile.

In the event that the peripheral cutting set comprises a plurality of first peripheral cutting edges and a plurality of second peripheral cutting edges, the first and second are

Circumferential cutting alternately arranged in the direction of rotation or circumference, i.e. such that a second circumferential cutting edge follows a first circumferential cutting edge. Alternatively, however, other arrangements of the first and the second are

Circumferential cutting possible. For example, the first and second

Circumferential cutting irregularly alternating in the direction of rotation or alternating in pairs, i.e. two second circumferential cutting edges follow two first

Circumferential cutting to be arranged.

In the preferred embodiment, as already mentioned, each first circumferential cutting edge can have a different cutting profile than every second circumferential cutting edge. In this case, the first and second peripheral cutting edges, measured in the axial direction, can have the same overall width and can be arranged axially on the same fleas. If the cutting teeth of the first and second peripheral cutting edges each have a rectangular tooth profile, which is defined by a front and rear tooth flank in the axial direction (in an axial feed direction of the circular milling tool or depth direction of the bore to be machined), the cutting teeth of each first peripheral cutting edge can, for example for machining the front (or back) flanks and cutting teeth each in the axial direction second circumferential cutting edge for the machining of the rear (or front) flanks of the end profile in the axial direction.

Alternatively, in the preferred embodiment, any first

Circumferential cutting edge and every second peripheral cutting edge have the same cutting profile, i.e. the first and second circumferential cutting edges are of the same design, provided that each first circumferential cutting edge is axially offset against every second circumferential cutting edge. Due to the axial offset of the first circumferential cutting edges relative to the second circumferential cutting edges in the state mounted on the circular milling tool, the same cutting edge profiles of the first and the second circumferential cutting edges leave different cutting marks on the bore surface to be machined. In this case too, the cutting teeth of the first and second circumferential cutting edges can each have a rectangular tooth profile, which is defined by a front and rear tooth flank in the axial direction (in an axial feed direction of the circular milling tool or depth direction of the bore to be machined), and can for example the cutting teeth of each first peripheral cutting edge for machining the front flanks in the axial direction and the cutting teeth of every second

Circumferential cutting edge can be designed for machining the rear flanks of the end profile in the axial direction. Wear identically designed circumferential cutting edges

advantageously to simplify the manufacture and assembly of the circular milling tool and thus keep the costs low.

Alternatively, in the preferred embodiment, the cutting teeth of the first peripheral cutting edges and / or the second peripheral cutting edges can have a non-rectangular tooth profile, such as e.g. an asymmetrical tooth profile or another symmetrical tooth profile, for example a trapezoidal tooth profile in which a tooth width increases with increasing diameter, i.e. radially outwards, increases or decreases, or a dovetail profile or a round profile.

In an advantageous development of the preferred ones discussed above

In one embodiment, the cutting teeth of each first and second circumferential cutting edge are preferably arranged at equal axial distances, ie with the same axial pitch, from one another and / or have the cutting teeth of each first and second Circumferential cutting edge preferably equal tooth widths. A tooth width is defined by an axial distance between a front cutting edge or tooth flank and a rear cutting edge or tooth flank of a cutting tooth. As an alternative to the preferred embodiment, the cutting teeth can be any first

The circumferential cutting edge has a different tooth width than the cutting teeth of every second circumferential cutting edge. According to the preferred embodiment, the tooth widths of the cutting teeth of each first and every second peripheral cutting edge are each smaller than the groove width of the micro-grooves of the end profile. According to the

preferred embodiment, the front cutting edges of each cutting tooth of each first circumferential cutting edge and the rear cutting edges of the associated cutting tooth of every second circumferential cutting edge (with associated cutting teeth projecting in the circumferential direction overlap) each at a distance of the groove width of the

End profile arranged.

In a preferred embodiment, the cutting teeth

rectangular tooth profile a tooth width of 100 to 400 pm and a tooth height of 50 to 250 pm. An axial distance between adjacent ones in the axial direction

Cutting teeth of each first and second peripheral cutting edge can preferably be between 200 and 700 μm. A total width of every first and second

Circumferential cutting edge can preferably be between 2 and 50 mm.

In an advantageous development of the preferred embodiment, the cutting profiles of the first peripheral cutting edge and the second peripheral cutting edge lie on the same diameter with respect to the axis of rotation of the circular milling tool. That is, the peripheral cutting edges of the cutting teeth, i.e. the outer diameter of the cutting profiles, the first peripheral cutting edge and the second peripheral cutting edge on a common cylindrical surface around the axis of rotation of the

Circular milling tool. Thus, the cutting profiles of the first peripheral cutting edge and the second peripheral cutting edge each differ only in the tooth width of the cutting teeth or in the groove width of the partial profile from the end profile.

In an advantageous development of the preferred embodiment, the at least two peripheral cutting edges of each peripheral cutting edge set are in Arranged circumferentially at equal angular intervals, ie with the same angular division. For example, each set of circumferential cutting edges has eight

Circumferential cutting, which are arranged in the circumferential direction at a distance of 45 °.

In the interest of a particularly economical circular milling operation, the peripheral cutting set can comprise at least a third peripheral cutting edge which has a cutting profile different from the cutting profiles of the first peripheral cutting edge and the second peripheral cutting edge. This means that the cutting profile of the third peripheral cutting edge both from the cutting profiles of the first peripheral cutting edge and the second peripheral cutting edge and from the defined groove profile of the micro-groove structure to be produced, i.e. the end profile. In particular, an overlay of the cutting edge profiles, i.e. a projection of the

Cutting profiles in the circumferential direction, the first circumferential cutting edge, the second circumferential cutting edge and the third circumferential cutting edge form the end profile.

In a preferred embodiment, the third peripheral cutting edge is arranged between the first peripheral cutting edge and the second peripheral cutting edge. This allows a cutting load to be applied evenly to the first, second and third

Circumferential cutting edge are distributed, since each peripheral cutting edge only has to take off as much material by how much the cutting profile of the peripheral cutting edge

Cutting profile of an adjacent peripheral cutting edge overlaps. The end profile can thus be produced particularly economically and reproducibly.

According to an advantageous further development, the third peripheral cutting edge can lie on a smaller diameter than the first peripheral cutting edge and / or the second peripheral cutting edge. In this case, for example, the groove depth and the groove width of the end profile can be produced by the first and the second peripheral cutting edge, while by means of the third peripheral cutting edge only the webs of the bore surface lying between adjacent micro-grooves are machined to a defined nominal diameter.

In the preferred embodiment, the third peripheral cutting edge can therefore have a single-tooth cutting profile. This allows a cutting profile with special high strength can be provided. The cutting profile thus generates the inside diameter of the bore surface over its entire axial extent.

The cutting tooth of the single-tooth cutting profile of the third peripheral cutting edge can have an axial tooth width which is essentially as large as that

Cutting width of the first peripheral cutting edge and / or the second peripheral cutting edge. In this case, the third circumferential cutting edge can machine an area with the same axial width as the first and / or second circumferential cutting edge and, provided that the first, second and third circumferential cutting edges of a circumferential cutting edge set are arranged axially at least substantially at the same height, the end profile by means of a

Tool can be finished.

In the preferred embodiment, the third peripheral cutting edge can

In particular, they have a wavy cutting profile, which causes an additional roughening in contrast to a straight cutting edge, so that the surfaces machined by the third peripheral cutting edge have a defined, constant roughness over their entire axial extent.

In a development of the preferred embodiment, the

Circumferential cutting edge set has several, in particular four, third circumferential cutting edges, which are each arranged between one of the plurality of first peripheral cutting edges and one of the plurality of second peripheral cutting edges. According to the development, every third peripheral cutting edge can lie on a smaller diameter than each first peripheral cutting edge and every second peripheral cutting edge and a single tooth

Have cutting edge profile, i.e. form a single-toothed peripheral cutting edge

Cutting tooth has an axial tooth width which is substantially as large as the cutting width of each first circumferential cutting edge or every second circumferential cutting edge. In contrast to the multi-toothed circumferential cutting edges of each first

Circumferential cutting edge and every second peripheral cutting edge, the axially overlapping cutting tracks of which produce a micro-groove structure which has a plurality of axial

spaced micro-grooves, the single-toothed circumferential cutting edge of every third circumferential cutting edge can have the inside diameter of the webs lying between the micro-grooves to edit. For this purpose, every third peripheral cutting edge can have a wavy cutting profile.

The peripheral cutting set can have a larger number of thirds

Circumferential cutting than on first peripheral cutting and / or on second

Have peripheral cutting. In particular, the number of thirds

Circumferential cutting the number of first circumferential cutting and second

Correspond to circumferential cutting together. In particular, the

Circumferential cutting edge set includes as many circumferential cutting edges as are produced by the micro grooves, namely the first and the second circumferential cutting edges

Circumferential cutting that the webs between the micro grooves and thus the

Process the inside diameter, namely the third circumferential cutting edge, which means that the entire bore area can be machined evenly.

In a development of the preferred embodiment, the

Tool body of the circular milling tool on a plurality of axially staggered circumferential cutting sets. The preferred embodiment has so many peripheral cutting sets that the entire axial width of the

Circumferential cutting sets greater than or equal to the depth of the to be machined

Hole surface is. As a result, the bore surface to be machined can be machined over its entire axial extent by means of a 360 ° circulation of the circular milling tool, without the circular milling tool having to be readjusted in the axial direction or several circular milling processes being necessary.

In the preferred embodiment, two axially successive circumferential cutting sets can be rotated relative to one another by a predetermined angle about the axis of rotation. As a result, the peripheral cutting edges of the two adjacent peripheral cutting edge sets are arranged one after the other, as seen in the peripheral or cutting direction, so that they cut into the cylindrical surface to be machined at different times. In particular, the circumferential cutting edge sets are arranged such that circumferential cutting edges each having the same cutting profile are arranged in the axial direction along helices. This arrangement lends itself to arranging two axially successive circumferential cutting sets in such a way that they overlap one another in the axial direction. As a result, the cutting profiles of adjacent peripheral cutting sets projected in the circumferential direction overlap, so that a machined bore surface does not contain any unprocessed surface areas.

In the preferred embodiment, as already mentioned, the peripheral cutting edges can each be formed on a cutting element, for example plate-shaped, which is fixed directly or indirectly on the tool base body.

For example, based on the model discussed above

Circular milling tool associated with a set of peripheral cutting edges

Cutting elements on a disc milling cutter carried by the base body on

Tool body be determined indirectly. Such side milling cutters are already well known, so that only the first, second and third

Circumferential cutting designed according to the invention and must be attached to the side milling cutter for producing a circular milling tool according to the invention. Alternatively, the cutting elements can be directly on

Tool body fixed, e.g. arranged in circumferentially open receiving pockets and fastened positively, non-positively and / or cohesively.

Regardless of whether the cutting elements are fixed indirectly or directly on the basic tool body, the circular milling tool can have a number of flutes corresponding to the number of peripheral cutting edges of a peripheral cutting set. The flutes can be worked into the basic tool body or, for example, by a helical arrangement of the

Circumferential cutting results, so that a chip flow is guaranteed, which prevents chips that get jammed between the tool and the bore.

From a functional point of view, the tool base body can be divided into a carrier section carrying the at least one peripheral cutting edge set and a shaft section axially adjoining the carrier section for connecting the

Circular milling tool with a cutting or interface of a Machine tool system can be subdivided so that the circular milling tool can be used with a machine tool system in a manner known to those skilled in the art.

The object of the invention is also achieved by a method for producing a micro-groove structure in a bore in a particularly metallic workpiece, e.g. solved a cylinder bore in an internal combustion engine, wherein the micro-groove structure comprises a plurality of axially spaced and circular circumferential micro-grooves, each with a defined groove profile. According to the method according to the invention, a bore surface is thereby through a 360 ° circulation of a rotary driven circular milling tool according to the invention about the bore axis

Finished that the cutting traces left in the bore surface of the circumferential cutting edges per circumferential cutting edge set of the circular milling tool overlap each other in the axial direction so that they meet the defined groove profile of the

Show micro-groove structure.

If the at least one circumferential cutting edge set has at least a first one

Circumferential cutting edge, comprising at least a second peripheral cutting edge and at least a third peripheral cutting edge, can be achieved by means of an inventive

Circular milling tool in a 360 ° revolution a cylindrical workpiece surface with a micro-groove structure, which has a groove profile, which is defined by a plurality of axially spaced, circular circumferential micro-grooves and on one

predetermined diameter is reproducibly finished.

In other words, the circular milling tool is designed such that

at least a first peripheral cutting edge in a machined cylindrical

Workpiece surface generates a first cutting track, which is designed as a circumferential circumferential first groove profile, which corresponds to a part of the end profile, and at least a second circumferential cutting edge generates a second cutting track, which as a circumferential circumferential second groove profile, which is part of the

End profile corresponds, is formed. The first and the second groove profile, ie the first and the second cutting track, are each designed differently from the end profile. The first and the second groove profile complement each other End profile. In particular, the first and the second groove profile complement one another in such a way that the first and second groove profile largely overlap, for example more than 50%, particularly preferably more than 80%. The circumferential cutting edge set can also have at least one third circumferential cutting edge which creates a third cutting track in the workpiece surface, the first, the second and the third

Add cutting track to the end profile.

The invention is explained below with the aid of drawings. Show it:

1 is a side view of a circular milling tool according to the invention,

2 is a front view of the circular milling tool,

FIGS. 3 to 6 longitudinal sectional views of the cutting profiles of the peripheral cutting edges of the circular milling tool,

FIGS. 7 to 9 schematic representations of cutting teeth of the cutting profiles in engagement with an end profile,

10 is a perspective view of the circular milling tool in a first preferred embodiment,

FIGS. 1 1 to 13 is a perspective view, a side view and a

Front view of the circular milling tool in a second preferred embodiment, and

14 is a perspective view of a cutting element.

In the following, preferred embodiments of a circular milling tool according to the invention are described in more detail with the aid of the figures. The figures are merely schematic in nature and serve to understand the invention. The same elements are identified by the same reference symbols. The

Circular milling tool is designed to bore in a cylindrical surface in a particularly metallic workpiece, for example the piston running surface of a

Cylinder bore or a cylinder liner in an internal combustion engine to be mechanically roughened by creating a micro-groove structure in the surface. The micro-groove structure to be produced has a defined groove profile, which is defined by a plurality of circular, circumferential micro-grooves arranged at an axial distance from one another, in order to obtain a good adhesive base for a surface layer to be applied in particular by thermal spraying. The defined groove profile of the micro-groove structure to be produced is referred to below as the end profile.

A circular milling tool 1 according to the invention has a tool base body 10 which can be driven in rotation about a longitudinal central or rotational axis 2 and which can be functionally divided into a shank section 11 and a carrier section 12. The

Shaft section 11 can be connected to an interface of a (not shown)

Machine tool system are connected to drive the tool body 10 about the axis of rotation 2. The shaft section 11 points in the illustrated

Embodiments a hollow shaft taper (HSK). The shank section 11 can also have, for example, a steep taper shank or a cylindrical shank for connecting the circular milling tool 1 to the machine tool system.

In a preferred first embodiment shown in FIG. 1, the circular milling tool 1 has a modular structure. The carrier section 2 carries a plurality of circumferentially cutting cutting tools 20 to 34 which are arranged at defined axial distances from one another on the tool base body 10 and which are each formed in the illustrated embodiment by a disk milling cutter. In the illustrated embodiment, the carrier section 12 carries fifteen

Cutting tools 20 to 34 so that a cutting part 13, e.g. with a length of 154 mm. The cutting tools 20 to 34 each have the same nominal diameter, e.g. 70 mm, which is smaller than the inside diameter of the

machining hole. A clamping screw 14 screwed on the end face into the tool round body 10 clamps the cutting tools 20 to 34 against an axial stop formed on the shaft base body 10. The clamping screw 14 is executed as a cap screw, the head 15 presses against the foremost cutting tool 20.

The cutting tools 20 to 34 each have the same structure. For the sake of simplicity, the structure of the cutting tool 20 is therefore described below, since the structure of the cutting tools 21 to 34 is analogous to this.

2 shows a front view of the circular milling cutter 1. The

Cutting tool 20 has a disk-shaped cutter base body 35, which carries a plurality of cutting elements 36 arranged in series in the circumferential direction. Each cutting element 36 has a peripheral cutting edge 37, the

Circumferential cutting 37 of the cutting elements 36 form a peripheral cutting set of the cutting tool 20. In the exemplary embodiment shown, the cutting tool 20 has eight cutting elements 36. Thus the

Circumferential cutting edge set of the cutting tool 20 eight circumferential cutting edges 37, which in the illustrated embodiment are equally distributed over the circumference of the

Cutting tool 20 are arranged. The circumferential cutting edge set of the

Cutting tool 20 has first peripheral cutting edges 38, second peripheral cutting edges 39 and third peripheral cutting edges 40, each of which has a cutting edge profile that is different from the end profile, in particular corresponds to a part of the end profile.

In the illustrated embodiment, the peripheral cutting set of the cutting tool 20 has two first peripheral cutting edges 38, two second

Circumferential cutting edges 39 and four third peripheral cutting edges 40. In Fig. 2 it can be seen that the first peripheral cutting edges 38 are opposite, i.e. in

Circumferential direction offset by 180 °, are arranged. The second peripheral cutting edges 39 are opposite, i.e. circumferentially offset by 180 °, and between the first circumferential cutting edges 38, i.e. offset in the circumferential direction by 90 ° to the first circumferential cutting edges 38. The first circumferential cutting edges 38 and the second circumferential cutting edges 39 are therefore regularly alternately arranged in the circumferential direction. The third circumferential cutting edges 40 are each offset by 90 ° to one another in the circumferential direction and between a respective first one

Circumferential cutting edge 38 and a second peripheral cutting edge 39, ie in the circumferential direction offset by 45 ° to a first circumferential cutting edge 38 and a second circumferential cutting edge 39, respectively. The result is the following arrangement of the circumferential cutting edges 37 arranged in series in the circumferential direction: first

Circumferential cutter 38, third circumferential cutter 40, second circumferential cutter 39, third circumferential cutter 40, first circumferential cutter 38, third circumferential cutter 40, second circumferential cutter 39, third circumferential cutter 40.

The first circumferential cutting edges 38, the second circumferential cutting edges 39 and the third circumferential cutting edges 40 each have a cutting edge profile which is different both from the end profile and from the cutting edge profiles of the respective other peripheral cutting edges 38, 39, 40. The cutting edge profiles of the first peripheral cutting edges 38, second peripheral cutting edges 39 and third peripheral cutting edges 40 therefore leave different cutting traces in a machined bore surface. The

Cutting edge profiles of the first peripheral cutting edges 38, the second peripheral cutting edges 39 and the third peripheral cutting edges 40 engage in the one to be machined

So bore surface so that they each only a part of the end profile, i.e. create a partial profile, but together produce the complete final profile. This is achieved in that the cutting edge profiles of the first peripheral cutting edges 38, the second peripheral cutting edges 39 and the third peripheral cutting edges 40 in

According to the invention, the circumferential direction overlaps in the manner or so far in the axial direction and / or in the radial direction that they together form the end profile.

The circular milling tool 1 therefore works as follows: Will that

Circular milling tool 1 driven in the direction of rotation, cut the first, second and third peripheral cutting edges 38, 39, 40 in succession in the bore to be machined. Thus, each of the first, second, and third peripheral cutting edges 38, 39, 40 removes material to map a portion of the end profile. In other words, the first peripheral cutting edges 38 cut a first cutting track, which is part of the end profile, ie a partial profile, and corresponds to the cutting profile of the first peripheral cutting edges 38, into the bore surface. The profile area of the first cutting track is smaller than the profile area of the end profile, for example the first cutting track has a groove profile with a smaller groove width. The circular milling tool 1 continues to rotate its axis of rotation 2, the third circumferential cutting edges 40 cut a third cutting track, which is a partial profile of the end profile and the cutting profile of the third

Corresponds to circumferential cutting 40 in the bore surface. The third cutting track is different from the end profile, for example the third cutting track lies on a smaller diameter around the bore axis than the first cutting track. If the circular milling tool 1 rotates further about its axis of rotation 2, the second peripheral cutting edges 39 cut a second cutting track, which is part of the end profile and corresponds to the shape of the cutting edge profile of the second peripheral cutting edges 39, into the surface of the bore. Analogous to the first cut track, the profile area of the second cut track is smaller than the profile area of the end profile, for example the second cut track has a groove profile with a smaller groove width than the end profile, but deviates from the first cut track, for example the second cut track has a groove profile with the same groove width as the first cutting track, but is axially offset. In the preferred embodiment, the first and the second cutting track overlap to a large extent in the axial direction, for example with more than 80% of the respective groove width.

3 shows a cutting element 36 which forms one of the first circumferential cutting edges 38. The cutting profile of the first peripheral cutting edge 38 has a plurality of cutting teeth 38a, which are at the same axial tooth spacing from one another

are arranged and each have the same tooth width and tooth height. The cutting teeth 38a thus have a constant axial pitch. The cutting teeth 38a of the first peripheral cutting edge 38 each have a rectangular profile in the illustrated embodiment. The tooth width B38a is measured by the distance between a front tooth flank 38b (in the axial feed direction of the circular milling tool) and a rear tooth flank 38c of a cutting tooth 38a (in the axial feed direction of the circular milling tool). The tooth height H38a is measured by the distance between a tooth base 38d and a tooth tip 38e. Each tooth base 38d of the cutting teeth 38a lies on a constant one

Base diameter D38d. Each tooth tip 38e of the cutting teeth 38a lies on a constant tooth tip diameter D38e, which also forms the diameter D38 of the first peripheral cutting edge 38. The axial tooth spacing A _38a is measured by the distance between a rear tooth flank 38c of a cutting tooth 38a and one front tooth flank 38b of an adjacent cutting tooth 38a arranged behind it in the axial feed direction of the circular milling machine 1. The axial pitch T38a with which the cutting teeth 38a are arranged is measured by the distance between the front tooth flanks 38b in each case of two cutting teeth 38a adjacent in the axial direction. The axial pitch T38a thus corresponds to the sum of the axial tooth spacing A38a and the tooth width B38a. Each first peripheral cutting edge 38 has an overall width B38.

FIGS. 4a and 4b show two variants of a cutting element 36 which forms one of the second peripheral cutting edges 39. The cutting profile every second

Circumferential cutting edge 39 has a plurality of cutting teeth 39a, which are arranged at the same axial tooth spacing from one another and each have the same tooth width and tooth height. The cutting teeth 39a thus have a constant axial pitch. The cutting teeth 39a of the second peripheral cutting edges 39 each have a rectangular profile in the illustrated embodiment. The tooth width B39a is measured by the distance between a front tooth flank 39b (in the feed direction of the circular milling tool) and a rear tooth flank 39c of a cutting tooth 39a (in the feed direction of the circular milling tool). The tooth height H39a is measured by the distance between a tooth base 39d and a tooth tip 39e. Each tooth base 39d of the cutting teeth 39a lies on a constant one

Base diameter D39d. Each tooth tip 39e of the cutting teeth 39a lies on a constant tooth tip diameter D39e, which also forms the diameter D39 of the second peripheral cutting edge 39. The axial tooth spacing A39a is measured by the distance between a rear tooth flank 39c of a cutting tooth 39a and a front tooth flank 39b of an adjacent cutting tooth 39a arranged behind it in the axial feed direction of the circular milling machine 1. The axial pitch T 39a with which the cutting teeth 39a are arranged is measured by the distance between the front tooth flanks 39b of two cutting teeth 39a adjacent in the axial direction. The axial pitch T39a thus corresponds to the sum of the axial tooth spacing A39a and the tooth width B39a. Every second peripheral cutting edge 39 has an overall width B39. The cutting profile of a first peripheral cutting edge 38 (see FIG. 3) corresponds in the illustrated embodiment to the cutting profile of a second peripheral cutting edge 39 (see FIGS. 4a and 4b) with regard to the axial pitch of the cutting teeth 38a and 39a (T38a = T39a), the axial tooth spacing the cutting teeth 38a or 39a (A38a = A39a), the tooth width of the cutting teeth 38a or 39a (B38a = B39a), the tooth height of the cutting teeth 38a or 39a (Fl38a = H39a), the

Tooth base diameter (D38d = D39d), the tooth tip diameter (D38e = D39e), the diameter of the peripheral cutting edges 38 or 39 (D38 = D39) and the total width of the peripheral cutting edge 38 or 39 (B38 = B39). The cutting profile of a peripheral cutting edge 39 shown in FIG. 4a differs from the cutting profile of a peripheral cutting edge 38 shown in FIG. 3 in that the cutting teeth 39a are offset axially by an offset V with respect to the cutting teeth 38a, but the second peripheral cutting edge 39 is axially on the same height as the first

Circumferential cutting edge 38 is arranged. The cutting profile of a circumferential cutting edge 39 shown in FIG. 4b has the same cutting profile as a circumferential cutting edge 38 shown in FIG. 3, but the second circumferential cutting edge 39 shown in FIG. 4b is offset axially by the offset V with respect to the first circumferential cutting edge 38. For a better understanding, the offset V is shown in the

Embodiments not shown to scale, but enlarged.

In order to generate a different groove profile in a bore surface, the ones in FIGS. 4a and 4b possible variants: (1) the circumferential cutting edges 38 and 39 are arranged in the axial direction at the same height, while the

Cutting teeth 38a of the peripheral cutting edge 39 against the cutting teeth 38a

Circumferential cutting edge 38 is axially offset by the offset V, as shown in Fig. 4a; or (2) the identically designed second peripheral cutting edges 38 and 39 are axially offset from one another by the offset V, as shown in FIG. 4b.

5 shows a cutting element 36 which forms one of the third peripheral cutting edges 40. The cutting profile of every third circumferential cutting edge 40 is designed with one tooth. The one cutting tooth 40a of every third peripheral cutting edge 40 has a wave profile in the embodiment shown, as shown in FIG. 5. The third peripheral cutting edge 40 has an overall width B ₄₀ . The cutting profile of the third Circumferential cutting edge 40 is designed to machine the webs S between the grooves of the end profile of a machined bore surface to a predetermined diameter DR. The third peripheral cutting edges 40 therefore have a smaller diameter D ₄ o than the first peripheral cutting edges 38 (D ₃₈ > D ₄ o) and the second peripheral cutting edges 39 (D39> D ₄ o). The diameter D ₄ o of the third circumferential cutting edges 40 is larger than the tooth base diameter D38 _{d of} the first circumferential cutting edges

38 (D38d <D ₄₀ ) and as the tooth base diameter Ü39d of the second circumferential cutting edges

39 (D39d <D ₄₀ ).

6 shows the end profile, which results from a superimposition of the cutting traces or partial profiles left in a machined bore surface

Circumferential cutting edges 38, 39 and 40 of a peripheral cutting edge set result. The end profile has a multiplicity of micro-grooves, each of which has the same groove width BR and groove depth HR. The webs S, which each have the same web width Bs, are arranged between adjacent micro-grooves. As a result, the micro grooves have a constant axial pitch TR. The groove width BR is measured by the distance between a front groove flank VRF and a rear groove flank HRF of a micro groove. The groove depth HR is measured by the distance between a groove base RG and a web tip SS. The web width Bs is measured by the distance between a rear groove flank HRF of a micro groove and a front groove flank VRF of an adjacent one in the axial feed direction of the

Circular milling tool arranged behind micro groove. The axial pitch TR with which the micro-grooves are arranged is measured by the distance between the front groove flanks VRF of two micro-grooves adjacent in the axial direction. The

Web tips SS lie on a diameter that forms the inside diameter DR of the micro grooves. The micro grooves of the end profile have a groove width BR and a groove depth HR. The groove width BR is larger than the tooth width B38a or B39a (BR> B383, BR> B39a), the groove depth HR is smaller than the tooth height H38a or H39a (H <H38a, HR <H39a), the axial pitch TR corresponds to that axial pitch T38 or T39 (TR = T38, TR = T39) and the diameter DR of the end profile is smaller than the diameter D38 or D39 (DR <D38, DR <D39), equal to the diameter D ₄₀ (DR = D ₄₀ ) and larger than the tooth base diameter D3ed or Ü39d (D> D38d, ÜR> D39d). FIGS. 7 to 9 schematically show a section of the end profile of FIG

machined bore surface and the engagement of the first, second and third peripheral cutting edges 38, 39, 40 in the end profile. The first circumferential cutting edge 38 works with its rear tooth flanks 38c of the cutting teeth 38a on the rear groove flanks HRF of the end profile, while the second circumferential cutting edge 39 processes the front groove flanks 39b of the cutting teeth 39a on the front groove flanks VRF of the end profile. The groove base RG of the end profile is machined by the tooth tips 38d, 39d of the first and second peripheral cutting edges 38, 39. The third peripheral cutting edge 40 processes the webs S and thereby the diameter DR of the end profile.

FIGS. 7 and 8 show that, as already mentioned, the tooth widths B38a, B ₃ 9a of the cutting teeth 38a, 39a of the first and the second peripheral cutting edges 38, 39 are smaller than the groove width BR between the front groove flank VRF and the rear groove flank HRF. FIG. 9 shows that, as already mentioned, the webs S between the micro-grooves of the end profile are brought to the diameter DR by the third peripheral cutting edges 40. The machining load for producing the end profile is thus distributed to the first, second and third peripheral sheaths 38, 39, 40, which each produce only a part of the end profile.

10 shows the perspective view of the first preferred embodiment of the circular milling tool 1. The cutting tools 20 to 34 are

non-positively fixed on the tool body 10. The cutting tools 20 to 34 take the model of that specified in DE 10 2016 216 464 A1

Circular milling tool with its respective central recess on the peg-like support section 12. The cutting tools 20 to 34 are circumferentially by means of a driver, such as a key against which

Tool body 10 fixed in a rotationally fixed. The cutting tools 20 to 34 are arranged rotated relative to one another, so that the first, second and third

Circumferential cutting edges 38, 39, 40 each run along helical lines or helices. This means that in each case two sets of circumferential cutting edges that follow one another axially are rotated relative to one another by a predetermined angle. The first peripheral cutting edges 38 and second peripheral cutting edges 39 and third, respectively Circumferential cutting 40 of two axially successive cutting tools are arranged one behind the other in the circumferential direction or direction of rotation, so that they cut into the cylindrical surface to be machined at different times. This creates helical flutes 16, the number of which corresponds to the number of circumferential cutting edges 37 per circumferential cutting edge set. In the illustrated embodiment, eight flutes 16 are formed. Viewed overall, the cutting part 13 of the circular milling tool 1 is helically grooved. The circumferential cutting edges 37 in each case of two axially successive circumferential cutting edge sets overlap one another in the axial direction. In the embodiment shown in FIG. 10, the peripheral cutting edges 37 are each attached indirectly to the tool base body 10 via the cutting tools 20 to 34.

FIGS. 1 1 to 13 show a second preferred embodiment of the

Circular milling tool 1 according to the invention. The second preferred embodiment corresponds essentially to the first preferred embodiment. Therefore, only the differences are described below. The peripheral cutting edges 37 are each formed on a cutting element 50 and the cutting elements 50 are individually attached to a carrier section 12 of the tool base body 10. In contrast to the first embodiment, the circumferential cutting edges 37 are not fixed indirectly via a cutting tool 20 to 34, but directly on the tool base body 10. For this purpose, each cutting element 50 is arranged in a pocket-like recess on the carrier section 12 of the tool base body 10 and screwed to the carrier section 12. A plurality of cutting elements 50 arranged axially at the same height and evenly distributed over the circumference form a circumferential cutting set. The peripheral cutting set has first peripheral cutting edges 38 described above and second peripheral cutting edges 39 described above. The peripheral cutting edge set can also have third peripheral cutting edges 40 described above.

As shown in FIG. 14, the cutting elements 50 are formed in two parts and have a carrier body 50a and the cutting body 50b attached to it, for example soldering or gluing. The cutting body 50b can, for example, be made of PCD, CBN or a comparable hard material during the Carrier body 50a can be made of solid carbide, steel or the like, for example.

Claims

Expectations

1. Circular milling tool (1) for producing a micro-groove structure in the cylindrical surface of a bore in a particularly metallic workpiece, e.g. a cylinder bore in an internal combustion engine, the micro-groove structure having a groove profile defined by a plurality of axially spaced, circular

circumferential micro grooves is defined with:

a tool base (10) which can be driven about an axis of rotation and which carries a peripheral cutting set with a first peripheral cutting edge (38) and a second peripheral cutting edge (39) which are arranged in a row in the peripheral direction, characterized in that

the first circumferential cutting edge (38) and the second circumferential cutting edge (39) each have a cutting profile which is different from the defined groove profile of the micro-groove structure to be produced, and

the cutting edge profiles of the peripheral cutting edges (38, 39) of the peripheral cutting set projected in the circumferential direction overlap each other in the axial direction to such an extent that they together form the defined groove profile of the micro-groove structure to be produced.

2. Circular milling tool (1) according to claim 1, characterized in that the first peripheral cutting edge (38) and the second peripheral cutting edge (39) each have a cutting profile having a plurality of cutting teeth (38a, 39a) in the axial direction.

3. Circular milling tool (1) according to claim 2, characterized in that the cutting teeth (38a, 39a) of the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39) each have a rectangular tooth profile.

4. Circular milling tool (1) according to claim 2 or 3, characterized in that the cutting teeth (38a, 39a) of the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39) are arranged at equal axial distances.

5. Circular milling tool (1) according to one of claims 2 to 4, characterized in that the cutting teeth (38a, 39a) of the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39) have tooth widths (B38a, B39a) of the same size.

6. circular milling tool (1) according to any one of claims 1 to 5, characterized in that the first peripheral cutting edge (38) and the second

Circumferential cutting edge (39) lie on the same diameter (D38, D39).

7. Circular milling tool (1) according to one of claims 1 to 6, characterized by several, in particular two, first peripheral cutting edges (38) and several, in particular two, second peripheral cutting edges (39) which are arranged alternately in the circumferential direction.

8. Circular milling tool (1) according to one of claims 1 to 7, characterized in that the peripheral cutting set comprises a third peripheral cutting edge (40) which one of the cutting profile of the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39) and / or has a cutting profile different from the defined groove profile of the microstructure to be produced.

9. Circular milling tool (1) according to claim 8, characterized in that the third peripheral cutting edge (40) is arranged between the first peripheral cutting edge (38) and the second peripheral cutting edge (39).

10. circular milling tool (1) according to claim 8 or 9, characterized in that the third peripheral cutting edge (40) on a smaller diameter (D ₄ o) than the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39).

1 1. circular milling tool (1) according to any one of claims 8 to 10, characterized in that the third peripheral cutting edge (40) has a single-tooth cutting profile.

12. Circular milling tool (1) according to claim 1 1, characterized in that a cutting tooth (40a) of the single-tooth cutting profile of the third peripheral cutting edge (40) has an axial tooth width (B ₄ o) which is substantially as large as one

Cutting width (B38, B39) of the first peripheral cutting edge (38) and / or the second peripheral cutting edge (39).

13. Circular milling tool (1) according to one of claims 8 to 12, characterized in that the third peripheral cutting edge (40) is a wave-shaped

Has cutting edge profile.

14. Circular milling tool (1) according to one of claims 8 to 13, characterized by a plurality, in particular four, third peripheral cutting edges (40), which are each arranged between one of the plurality of first peripheral cutting edges (38) and one of the plurality of second peripheral cutting edges (39) ,

15. Circular milling tool (1) according to claim 14, characterized in that the peripheral cutting set has a larger number of third peripheral cutting edges (40) than first peripheral cutting edges (38) and / or second peripheral cutting edges (39).

16. Circular milling tool (1) according to one of claims 1 to 15, characterized by a plurality of axially staggered circumferential cutting sets.

17. Circular milling tool (1) according to claim 16, characterized in that in each case two axially successive circumferential cutting sets

are rotated against each other by a predetermined angle about the axis of rotation.

18. Circular milling tool (1) according to claim 17, characterized in that in each case two axially successive circumferential cutting sets overlap one another in the axial direction.

19. Circular milling tool (1) according to claim 1, characterized in that the peripheral cutting edges (37) are each on a Tool base body indirectly or directly defined cutting element (36, 50) are formed.

20. Circular milling tool (1) according to claim 19, characterized in that the cutting elements (36) are fixed to a disc milling cutter (20 to 34) carried by the tool base body (10).

21. Circular milling tool (1) according to one of claims 1 to 20, characterized by a number of flutes (16) corresponding to the number of peripheral cutting edges (37) of the peripheral cutting set.

22. Circular milling tool (1) according to one of claims 1 to 21, characterized in that the tool base body (10) has a carrier section (12) carrying the peripheral cutting edge set and an axially on the carrier section (12)

has a subsequent shaft section (11) for connecting the circular milling tool (1) to a separating or interface of a machine tool system.

23. Method for producing a micro-groove structure in a bore in a particularly metallic workpiece, e.g. a cylinder bore in one

Internal combustion engine, which comprises a plurality of axially spaced and circular circumferential micro grooves, each with a defined groove profile, by means of a rotationally driven circular milling tool (1) circulating around the bore axis, characterized in that

the bore surface is finished by a 360 ° circulation of a rotary driven circular milling tool (1) according to one of claims 1 to 22 in that the cutting traces left in the bore surface of the

Circumferential cutting edges (37) per circumferential cutting edge set of the circular milling tool (1) overlap with one another in the axial direction in such a way that they represent the defined groove profile of the micro-groove structure.