WO2003051564A1

WO2003051564A1 - Machining tool

Info

Publication number: WO2003051564A1
Application number: PCT/EP2002/013281
Authority: WO
Inventors: Gustav Werthwein
Original assignee: Gustav Werthwein
Priority date: 2001-11-27
Filing date: 2002-11-26
Publication date: 2003-06-26
Also published as: AU2002358539A1; DE10157787A1

Abstract

The invention relates to a machining tool (10) that is comprised of a holder (11) and a cutting head (12). The tool elements (11; 12) are interlinked both in the axial and in the transverse direction via coupling elements (13). Said coupling elements (13) are configured by one annular front face (21, 31) each, by an inner conical surface (22) and outer conical surface (32), by an inner and outer cylindrical guiding surface (23, 33) and by an internal thread (24) and external thread (34).

Description

Machining tool

In the machining of workpieces, particularly in so-called machining centers, tools that can be divided are increasingly being used. In your case, the tool cutting edges are arranged on a separate part, a cutter holder or cutting head, which can be coupled to the other part of the tool, the tool holder or holder for short, by means of coupling elements. The holder has coupling surfaces at one end for coupling the tool to a machine tool. There are largely standardized embodiments for this part of the holder. The coupling elements on the holder side are arranged at the other end region of the holder and are referred to below as primary coupling elements for better differentiation. The cutting head has on one length section one or more cutting edges, which are generally designed as cutting inserts made of a high-quality cutting material, and on the other length section has coupling elements which are matched to the coupling elements on the holder and which are referred to below as secondary coupling elements ,

In a known divisible tool of this type, the primary coupling elements on the holder are formed by an annular end face and by an adjoining inner cone face which is relatively short. As further coupling elements, a length section with an internal thread is provided both on the holder and on the cutting head, which are designed in opposite directions and which cooperate with a threaded pin, which has two longitudinal sections, each with an external thread, which are also designed in opposite directions. The two end faces and the inner cone surface and the outer cone surface can be produced very precisely as smooth circumferential surfaces, so that a very high concentricity can be achieved with the cutting head. In contrast, the two internal threads and the two external threads can only be produced with relatively large tolerances. In the case of the internal threads in particular, an axial offset and / or an angular offset of the thread axis relative to the axis of the relevant tool part can occur. This can result in considerable lateral forces which can lead to the cutting head being inclined relative to the axis of the holder. This leads to a reduction in concentricity and therefore to wobbling of the cutting head.

This danger is even greater if, instead of the two internal threads and the set screw, there is only one internal thread on the holder and on the cutting head at the length section with the outer cone, another length section with an external thread, i.e. a threaded pin, connected in one piece. Because of the rigid connection of this external thread with the

In the event of an axis offset and / or angular offset of one or both threaded sections, the resulting lateral force acting on the cutting head can reach considerable values, as a result of which the concentricity of the cutting head can be greatly reduced. Such an impairment can also occur if a high transverse force is caused by strong cutting forces at the front end of the cutting head

The invention is based on the object of at least reducing or even eliminating unfavorable effects of a transverse force possibly generated by the fastening threads on the precise seating of the cutting head. This object is achieved by a tool with the features specified in claim 1. Characterized in that a further length portion is arranged on the holder between the length portion with the inner cone surface and the length portion with the internal thread, which has a cylindrical guide surface, the axis of which is aligned with the axis of the inner cone surface, and in that in a corresponding manner on the cutting head between The longitudinal section with the outer conical surface and the longitudinal section with the external thread are also arranged a further longitudinal section which is provided with a cylindrical guide surface which is matched to the cylindrical guide surface on the holder and whose axis is aligned with the axis of the outer conical surface the cutting head is supported at a point viewed from the longitudinal section with the cutting edges, beyond the two conical surfaces by the cylindrical guide surfaces, so that a transverse force emanating therefrom from the threaded surfaces does not lead to an inclined position of the longitudinal section it with the outer cone surface in the elastic length section with the inner cone surface of the holder and can lead to its widening.

In an embodiment according to claim 2, this support is significantly improved by the larger axial distance of the cylindrical guide surface from the outer cone surface.

An embodiment according to claim 3 ensures that a transverse force originating from the thread surfaces is absorbed by a large cylinder surface, so that the local load is significantly lower and a resulting elastic deformation is avoided.

By an embodiment according to claim 4, the support effect of the cylinder surfaces is also increased by the close mutual fit. An embodiment according to claim 5 ensures that a transverse force originating from the threaded surfaces can be absorbed by the cylindrical guide surfaces in the shortest possible way and that the torque which arises remains as small as possible.

The invention is explained in more detail below on the basis of an exemplary embodiment shown in the drawing. 1 shows a longitudinal section of a tool with a holder and a cutting head;

FIG. 2 shows a longitudinal section of the holder according to FIG. 1; 3 is a view of the cutting head of FIG .. 1

The tool 10 shown in FIG. 1 has a tool holder, or holder 11 for short, and a cutting head 12 as main assemblies. These two tool parts are separable from one another and are combined for use as a tool by means of a plurality of coupling elements to form the finished tool 10.

The holder 11 in turn has two parts, namely a base body 14 and an insert 15.

The base body 14 is designed in the area on the right in FIG. 1 in a manner which is customary for these tools and in general even standardized. In its area on the left in FIG. 1, it has a cylindrical recess 16 into which the insert 15 is inserted. The insert 15 and the base body 14 are non-detachably connected, generally by a shrink fit. This two-part design of the holder 11 has larger ones

Freedom in the design of the coupling elements of the holder in the area of the insert 15. In addition, if the insert, in particular its coupling elements, is damaged, it can be damaged Part of the holder 11 can be replaced more easily. Nevertheless, the holder 11 can also be formed in one piece.

As can be seen in more detail from FIG. 2, the holder 11 has coupling surfaces 17 for coupling to a machine tool at the end region located on the right in FIG. 2. These include an annular end face 18 and a relatively short outer cone face 19.

The holder-side coupling elements for coupling the holder 11 to the cutting head 12 are arranged on the holder 11 at its end region remote from the coupling surfaces 17. These coupling elements are referred to below as primary coupling elements 13.1. They are formed by an annular end surface 21 located at the end of the holder 11 and oriented normal to its longitudinal axis, by an adjoining coaxial inner conical surface 22, by an adjoining coaxial cylindrical guide surface 23 and by an internal thread 24.

On the cutting head 12 in the leftmost length section in FIG. 3 there are a number of plate seats 26 which are evenly distributed on the circumference. A cutting plate 27 is fastened to each of these by means of a fastening screw 28.

The part of the coupling elements 13 (FIG. 1) arranged on the cutting head 12, which are referred to below as secondary coupling elements 13.2, is formed by an annular end face 31, by an outer cone face 32, by a cylindrical guide face 33 and by an external thread 34.

To determine the effects of the theoretically given static overdetermination between the end face 21 and the inner cone To mitigate surface 22, the circumferential wall of the inner conical surface 22 is designed to be elastic so that when the cutting head 12 is joined to the holder 11, the inner conical surface 22 of the holder 11 is elastically stretched so far that the two end faces 21 and 22 are in mutual contact can be brought closer together under a certain investment force.

The end face 31 of the cutting head 12 is oriented normal to its longitudinal axis and has at least approximately the same inside diameter and the same outside diameter as the end face 21 on the holder 11

The outer cone surface 32 adjoining the end face 31 with a small clearance for the tool outlet is matched to the inner cone surface 22 on the holder 11. Likewise, the cylindrical guide surface 33 on the cutting head 12 is matched to the cylindrical guide surface 23 on the holder 11. Finally, the external thread 34 is matched to the internal thread 24 on the holder 11.

The cylindrical guide surface 33 on the cutting head 12 has an axial extent which is at least approximately the same as that of the outer cone surface 32.

As can be seen from Fig. 3, the cylindrical closes

Guide surface 33 does not directly touch the end of outer cone surface 32. In between is a length section 35, which has a smaller diameter than the guide surface 33. Due to the length section 35, the guide surface 33 is at a greater distance from the outer cone surface 32, so that the guidance or support torque of the guide surface 33 is correspondingly large in relation to the outer cone surface 32. Between the longitudinal section with the cylindrical guide surface 33 and the external thread 34 is only a relatively small axial distance for the necessary tool outlet. In addition, the external thread 34 is dimensioned as short as possible. As a result, a transverse force possibly emanating from the external thread 34 can be absorbed as directly as possible by the cylindrical guide surface 33 and can at most generate a small moment from the external thread 34. Neither can have any significant effect on the outer cone surface 32.

As can be seen from FIG. 3, a double flattening 36 is attached to the cutting head 12 at that length section which is located between the end face 31 and the vaginal area, for the use of an assembly tool, by means of which the cutting head 12 can be used with the for a perfect Seat required torque can be screwed into the holder 11 and can also be released therefrom.

LIST OF REFERENCE NUMBERS

10 tools

11 holders

12 cutting head

13 coupling elements

14 basic bodies

15 use

16 recess

17 coupling surfaces

18 end face

19 conical surface

21 end face

22 inner cone surface

23 guide surface

24 internal threads

26 insert seat

27 insert

28 fastening screw

31 end face

32 outer cone surface

33 guide surface

34 external thread

35 length section

36 flattening

Claims

claims

1. Tool for machining, with the features:

- there is a holder (11),

- - Which has coupling surfaces (17) for coupling to a machine tool at its one end region and

- which has primary coupling elements (13) for coupling a cutting head at its other end region - there is a cutting head (11),

- - The secondary at its one length section

Coupling elements (13.1) for coupling to the holder (11) and

- - On the other length section has at least one insert seat (26) for a cutting insert and a cutting insert (27) attached to it

- The primary coupling elements (13.1) on the holder (11) are formed by

- - An annular end face (21) and located at its end and at least approximately normal to its longitudinal axis

- - By an adjoining coaxial inner cone surface (22) and

- - by an adjoining coaxial internal thread (24),

- The secondary coupling elements (13.2) on the cutting head (12) are formed by

- one of the primary end face (21) on the holder (11) facing and coordinated secondary end face (31), - - a subsequent coaxial and on the

Inner cone surface (22) on the holder (11) matched outer cone surface (32 and

- An adjoining external thread (34), which is matched to the internal thread (24) on the holder (11), g e k e n n e e i c h n e t by the features:

a further length section with a cylindrical guide surface (23) is arranged on the holder (11) between the length section with the inner conical surface (22) and the length section with the internal thread (24),

- whose axis is aligned with the axis of the inner conical surface (), - a further longitudinal section with a cylindrical guide surface (33) is arranged on the cutting head (12) between the longitudinal section with the outer conical surface (32) and the longitudinal section with the external thread (34), - - Which is matched to the cylindrical guide surface (23) on the holder (11) and

- - whose axis is aligned with the axis of the outer cone surface (32).

2. Tool according to claim 1, having the features:

- The cylindrical guide surface (33) on the cutting head (12) has a certain distance in the axial direction from the outer cone surface (32)

3. Tool according to claim 1, having the features:

- The cylindrical guide surface (33) on the cutting head (12) has an axial extent which is at least approximately the same as that of the outer cone flat (32).

4. Tool according to claim 1, having the features:

- the two with each other cooperating cylindrical guide surfaces _(23/33) have a fitting accuracy level of at least approximately 6/7 IT.

5. Tool according to claim 1, having the features:

the longitudinal section with the external thread (34) has the smallest possible distance in the axial direction from the cylindrical guide surface (33),

- Preferably, the external thread (34) has the smallest possible axial extent.