Milling tool and cutting insert for such a milling tool

Abstract

A milling tool with a disk- or strip-shaped base body, which can be driven around an axis of rotation, and several cutting inserts arranged along the outer circumference of the base body on opposite sides from one another, wherein the cutting inserts, viewed in the axial direction, overlap one another. The invention also relates to a tangential cutting insert for a milling tool of the above-mentioned type, with two side surfaces, through which a fastening opening extends, and two face ends, wherein cutting edges are formed at the junction of the front faces to the side surfaces, wherein the fastening opening is positioned eccentrically.

Claims

1. A tangential cutting insert for a milling tool comprising two side surfaces, through which a fastening opening extends, and two front faces, wherein cutting edges are formed at the junction of the front faces with the side surfaces, wherein the fastening opening is eccentric with respect to a middle plane, M, of the cutting insert.

2. The cutting insert according to claim 1, wherein the fastening opening does not intersect the middle plane, M, of the cutting insert or intersects the middle plane, M, of the cutting insert by no more than 20% of a diameter of the fastening opening.

3. The cutting insert according to claim 1, wherein the front faces have a parallelogram shape.

4. The cutting insert according to claim 1, wherein the front faces have a rectangular shape with a projecting bead.

5. The cutting insert according to claim 1, wherein the middle plane, M, extends parallel to the front faces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained below with reference to two embodiments illustrated in the accompanying drawings. In the drawings:

(2) FIG. 1 shows a schematic view of a milling tool of the prior art;

(3) FIG. 2 shows a base body used in the milling tool of FIG. 1 with cutting inserts attached;

(4) FIG. 3 shows a schematic view of the axial forces acting on the base body 10 during milling;

(5) FIG. 4 shows a schematic view of a base body according to the invention;

(6) FIG. 5 shows a top view of a base body according to a first embodiment of the invention;

(7) FIG. 6 shows a perspective view of the base body of FIG. 5;

(8) FIG. 7 shows a side view of the base body of FIG. 5;

(9) FIG. 8 shows a perspective view of a cutting insert used in the first embodiment;

(10) FIG. 9 shows a side view of the base body of FIG. 8;

(11) FIG. 10 shows a top view of a base body according to a second embodiment;

(12) FIG. 11 shows a top view of a cutting insert according to a first variant;

(13) FIG. 12 shows a top view of a cutting insert according to a first variant.

DETAILED DESCRIPTION OF THE INVENTION

(14) In FIG. 4, a base body 10 for a milling tool according to the invention is shown schematically. The essential difference from the milling tool of the prior art is the fact that the cutting inserts 12, which are arranged on opposite sides of the base body 10, overlap one another, specifically, viewed in the axial direction along the axis of rotation. Expressed in another way: The cutting inserts 12 are arranged in pairs in such a manner that the offset between the two cutting edges of the cutting insert 12 of a pair, measured in the peripheral direction, is smaller than the length of the cutting inserts measured in the peripheral direction.

(15) In the basic principle of the base body 10 according to the invention shown in FIG. 4, the cutting edges S located toward the front in the direction of rotation D lie on the same line, indicated here by L.

(16) The consequence of the paired arrangement of the cutting inserts 12 on opposite sides of the base body 10 is that the axial components F.sub.a of the cutting forces are not offset relative to one another, as is shown in FIG. 3, but are opposite one another. Thus, there is no lever arm between the effective axial components of the cutting force, and no flexural stresses result on the base body 10.

(17) Although in the basic principle shown in FIG. 4 the cutting inserts completely overlap one another, it is fundamentally possible to position the cutting inserts 12 slightly offset relative to one another. It is obvious that, the larger the overlap, the smaller the flexural forces acting on the base body 10. It is particularly preferred that the overlap amounts to at least 50% of the width of a cutting insert measured in the peripheral direction. It is particularly preferred that the overlap amount to at least 80%, and especially advantageous if the overlap amounts to at least 90% of the width of a cutting insert measured in the peripheral direction.

(18) The cutting inserts 12 can be arranged to overlap one another in pairs, since they are provided with a fastening opening 20 that is arranged eccentrically. This results in the fact that the fastening screws 14 are also arranged eccentrically and are thus offset relative to one another. It is apparent from FIG. 4 that each of the cutting inserts arranged on the side surface of the base body 10 located at the top in FIG. 4 is attached to the base body with a fastening screw 14A, which, when viewed in the peripheral direction or direction of rotation D, lies in front of the fastening screws 14B, with which the cutting inserts 12 are attached to the base body 10, which are fastened to the side surface of the base body 10 located at the bottom in FIG. 4.

(19) A first embodiment of the invention will now be described based on FIGS. 5 to 9.

(20) In the base body 10 according to the first embodiment, the cutting inserts 12 are attached in pairs in such a manner that they completely overlap one another (see line L drawn in FIG. 5).

(21) As can be seen in FIGS. 6 and 7, a few cutting inserts 12 have an adjustment device 30 assigned to them with which these cutting inserts can be aligned.

(22) It is basically also possible to mount the cutting inserts 12 in their own cassettes, which are then, in turn, attached to the base body 10 with eccentrically positioned fastening screws.

(23) It can also be seen in FIGS. 5 to 7 that additional cutting inserts 40 are attached in a staggered arrangement on the peripheral surface of the base body 10.

(24) The cutting inserts 12 arranged on the side surfaces are tangential cutting inserts, each with two side surfaces 50, through which the fastening opening 20 extends. In addition, each cutting insert 12 has two front faces 52, which in the embodiment shown here, have the shape of a parallelogram in the broadest sense of the word. The cutting edges S are formed at the junction between the front faces 52 and the side surfaces 50.

(25) As can be seen in FIG. 9 in particular, the fastening opening 20 is arranged eccentrically. In this case, in the embodiment shown, it is arranged such that it is just tangential to a middle plane M of the cutting insert.

(26) Depending on the edge design requirements in any given case, it may also be provided that the fastening opening 20 slightly intersects the center plane M. Slightly here is assumed to mean an overlap amounting to no more than 20% of the diameter of the fastening opening 20.

(27) In FIG. 10, a base body for a milling tool according to a second embodiment is shown. Here, elements familiar from the first embodiment are given the same reference numbers, and therefore reference is made to the above explanations.

(28) The essential difference between the first and second embodiments consists of the fact that, in the second embodiment, two types of cutting inserts 12 are used on the side surfaces of the base body 10, namely the cutting inserts known from the first embodiment with parallelogram-shaped front faces 52 (also see FIG. 11) and cutting inserts 112, the front faces 152 of which (see FIG. 12) have a generally rectangular shape with a projecting bead at diagonally opposite corners.

(29) The cutting inserts 112 can be rough cutting inserts, and the cutting inserts 12 be finishing-rough cutting inserts.

(30) As can be seen in FIG. 10, the rough cutting inserts 112, viewed in the peripheral direction or the direction of rotation D, are offset relative to one another (see offset o). Nevertheless, they overlap when viewed in the axial direction.