Thread-whirling tool

Abstract

An annular thread-whirling head is disclosed, wherein, projecting over its periphery, indexable inserts are mounted in recesses in a first plane and are connected directly to the thread-whirling head. The plurality of indexable inserts lies with an indexable insert surface on a bearing surface of the recess, in a manner such that the indexable inserts are individually accessible, and may be assembled and disassembled in a simple manner by way of a fastening element. The produced swarf per indexable insert is minimized by way of the plurality of used indexable inserts, and the service life or the performance of the thread-whirling head is increased. Recesses may also be provided in a second plane so that, apart from a plurality of indexable inserts in a first plane, one may also arrange and fix a plurality of indexable inserts in a second plane, offset parallel to the first plane. A thread-whirling head with indexable inserts in a first and a second plane permits the manufacture of multiplex outer threads in one passage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is hereinafter described in combination with the drawings in which:

FIG. 1 shows a perspective view of the thread-whirling head according to the invention, with recesses in a first plane;

FIG. 2 shows a plan view of a thread-whirling head equipped with indexable inserts;

FIG. 3 shows a perspective view of a thread-whirling head with recesses in a first and a second plane; and

FIG. 4 shows a plan view of a thread-whirling head and a tool spindle, partly sectioned in the region of the thread-whirling head.

DETAILED DESCRIPTION

An annular thread-whirling head 1 according to the invention comprises a through-hole 10 and an inner periphery 11. The thread-whirling head 1 may be fastened with a lathe chuck on a tool spindle 12 of a lathe. During the thread-whirling, the thread-whirling head 1 is rotated at high rotational speeds about a rotation axis 5, which coincides with the cylinder axis of the thread-whirling head 1.

A workpiece spindle 61 on which a workpiece 6 is located, into which an outer thread 60 is milled from the solid material in a thread-whirling a manner, is positioned lying opposite the tool spindle 12. The workpiece spindle 61 rotates about a longitudinal axis 62 of the workpiece 6 at low rotational speeds, and may travel in a linear manner. Computer controlled lathes permit the fully automatic, software-controlled, operation of the entire thread-whirling process, so that the desired outer thread 60 may be carried out in one passage, without any interruption and without further interventions.

A plurality of mirror-symmetrical indexable inserts 3 are arranged distributed along the periphery of the thread-whirling head 1, in a plane 7 in recesses 2 at fixed, defined radial distances to the rotation axis 5. Each individual indexable insert 3 is arranged with an indexable insert surface 32 on a bearing surface 20 of the recess 2, such that a cutter 30 and at least one cutting edge 31 projects over the inner periphery 11 of the thread-whirling head 1 in the direction of the rotation axis 5.

As illustrated in FIG. 1, each individual bearing surface 20 of each individual recess 2 is located in the first plane 7 perpendicular to the rotation axis 5. Each bearing surface 20 is delimited by a first side wall 21 and a second side wall 22, so that the introduced indexable insert 3 is secured against a lateral displacement, and the orientation of the installation of the indexable inserts 3 is defined in a fixed manner by way of the first and second side wall 21. The indexable inserts 3 which are shown here by way of example, are designed in a parallelepiped manner and the section of the recesses 2 must be adapted thereto.

The indexable inserts 2 to be used comprise at least two cutters 30 on opposite sides of the indexable insert 3, wherein each cutter 30 comprises at least one cutting edge 31. One may however also apply indexable inserts 3 which comprise more than one cutting edge 31 per cutter 30. In order to reduce the swarf length at the indexable inserts 3 during the thread-whirling, swarf guiding steps 33 are provided, as is shown in FIG. 2, which lead away the swarf.

The indexable inserts 3 are fixed by fastening elements, which may be screws in one possible embodiment. It is likewise possible for the fastening element to fasten the indexable inserts 3 in the recesses 2 of the thread-whirling head 1 in a clamping manner.

In the embodiment disclosed herein, in each case a screw is led through a threaded bore 23 in each individual bearing surface 20, in each case through a through-hole 34 in each case in the center of an indexable insert 3, and screwed in and countersunk perpendicularly to the bearing surface 20. By way of this, each individual indexable insert 3 is connected with a positive and non-positive fit in each case to one recess, and thus directly connected to the thread-whirling head 1 lying in a first plane 7 perpendicularly to the rotation axis 5.

After chucking a tool 6 into the workpiece spindle 61, the workpiece 6 is rotated at a low rotational speed about its own rotation axis 62, and is introduced into the through-hole 10 of the thread-whirling head 1 by way of linear advance in the direction of the longitudinal axis 62, and is brought into contact with the cutting edges 31 of the thread-whirling head 1 by way of a linear movement perpendicular to the longitudinal axis 62. On thread-whirling, one may select the rotational direction of the tool spindle 12 and the workpiece spindle 61 to be the same or opposite. The cutting contact of the individual cutting edges 31 with the upper surface of the tool 6, and the programmed advance movement and the movement perpendicular to the rotation axis of the thread-whirling head 1, produces an outer thread 60 with a settable nominal diameter 601, core diameter 602 and pitch 603, depending on the desired result.

The individual indexable inserts 3 in a consecutive manner, are only in cutting contact with the workpiece 6 for a brief period, on account of the plurality of indexable inserts 3, by which means less swarf per indexable insert 3 arises, and the loading of each individual indexable insert 3 is reduced. More than one cutting edge 31, possibly even three cutting edges 31 are simultaneously in contact with the workpiece 6, depending on the selection of the desired core diameter 602, by which means the smoothness of running of the lathe may be increased. One may achieve greater performance during the thread-whirling by way of the thread-whirling head 1 according to the invention, by which means the outer thread 60 may be manufactured in short time intervals in one passage. Higher service lives of the thread-whirling head 1 may be achieved by way of the improvements described above.

If individual indexable inserts 3 are worn, due to the current design it is significantly simpler to exchange the individual indexable inserts 3 compared to the state of the art, since these are mounted in the individual recesses 2 in an easily accessible and simply disassemblable manner, whereby the refitting time is minimized. The indexable inserts 3 may be simply removed from the bearing surface 20 between the first side wall 21 and the second side wall, after the respective fastening element has been removed. After the indexing and the re-installation of the indexable insert 3, one requires no orientation and alignment of the indexable inserts 3 on account of the mounting in the described recesses 2.

On account of the design, the present invention may be extended to the extent that a plurality of indexable inserts 3 is additionally situated in a second plane 8 perpendicular to the rotation axis 5 and displaced parallel to the first plane 7. A thread-whirling head 1 which comprises recesses 2 in a first plane 7 and in a second plane 8, is disclosed in FIG. 3. The orientation and the direct fixation of the indexable inserts 3 on the thread-whirling head 1 is carried out as has already been described, and also in this case, ensures a simple and quick assembly and disassembly of the indexable inserts 3. It is also possible to produce multiplex outer threads 60 in one passage by way of the thread-whirling head 1 due to the use of indexable inserts 3 in a first 7 and a second plane 8 displaced thereto. The control of the lathe is to be programmed according to the application, so that the advance of the workpiece spindle 61 is adapted to the multiplex outer thread 60 or to the pitch 603 which is to be achieved.

LIST OF REFERENCE NUMERALS

1   thread-whirling head
10  through-hole (centric)
11  inner periphery
12  tool spindle
2   recess
20  bearing surface
21  first side wall
22  second side wall
23  threaded bore
3   indexable insert
30  cutter
31  cutting edge
32  indexable insert surface
33  chip guiding step
34  through-hole
5   rotation axis (of the thread-whirling head)
6   workpiece
60  outer thread
601 nominal diameter
602 core diameter
603 pitch
61  workpiece spindle
62  longitudinal axis
7   first plane
8   second plane

Claims

1. An annular thread-whirling head which may be fastened on a tool spindle of a lathe and may be rotated about a rotation axis, comprising a through-hole with an inner periphery and a plurality of inserts facing radially in the direction of the rotation axis, comprising at least one cutter with at least one cutting edge, wherein the inserts, projecting radially beyond the inner periphery in the direction of the rotation axis, are arranged such that the at least one cutting edge is guidable along a workpiece in a material-removing manner, said workpiece being mounted on a workpiece spindle, able to be guided in a linearly movable manner within the through-hole, and able to be guided in a rotatably movable manner along the cutters, by which means outer threads of various shapes may be produced in a thread-whirling manner from the solid material of the workpiece, wherein a plurality of mirror-symmetrical indexable inserts is used, wherein each individual indexable insert may be individually connected directly and with a direct positive and non-positive fit to the thread-whirling head, wherein each indexable insert with an indexable insert surface on a bearing surface of an individual, freely accessible recess, may be mounted in a first plane of the thread-whirling head perpendicularly to the rotation axis, radially orientated between a first side wall and a second side wall of the recess, and may be fixed by way of in each case a fastening element, wherein the distance of the indexable inserts along the periphery of the thread-whirling head is selected such that simultaneously, always more than one cutting edge is in contact with the workpiece.

2. A thread-whirling head according to claim 1, wherein the indexable inserts are rhombic.

3. A thread-whirling head according to claim 1, wherein the indexable inserts have swarf guiding steps in the region of the cutting edge, which simplify the breaking-off and the leading-away of the swarf.

4. A thread-whirling head according to claim 1, wherein the fastening element is a screw which may be screwed perpendicularly, crossing the indexable insert through a through-hole, into a threaded bore in the recess.

5. A thread-whirling head according to claim 1, wherein a plurality of mirror-symmetric indexable inserts directly and with a direct positive-fit and non-positive fit with the thread-whirling head, may be mounted individually in recesses, in a second plane which is arranged perpendicularly to the rotation axis and parallel to the first plane.

6. A thread-whirling head according to claim 5, wherein each individual indexable insert may be mounted with an indexable insert surface on a bearing surface of an individual freely accessible recess, and may be fixed in each case with a fastening element.