METHOD FOR MACHINING A WORKPIECE, TOOL HEAD FOR A LATHE, AND LATHE

Abstract

A method for machining a workpiece and a lathe are provided, as well a tool head (1) for a lathe (2), having a tool holder (5) retaining a machining tool (3), wherein the tool head (1) has at least one actuator (6) for generating an additional movement of the tool holder (5) in the form of an oscillating pivoting movement about at least one pivot axis (7)

Claims

1. A method for machining a workpiece (15), comprising: providing a material-removing machining tool (3) having at least one cutting edge (4), driving the workpiece (15) in rotation in order to generate a cutting movement, bringing the cutting edge (4) of the machining tool (3) into cutting engagement with the workpiece (15) by an advancement movement that includes an oscillating additional movement of the cutting edge (4) of the machining tool (3), and the oscillating additional movement of the cutting edge (4) of the machining tool (3) is an oscillating pivoting movement about at least one pivot axis (7).

2. The method as claimed in claim 1, wherein the advancement movement of the machining tool (3) comprises at least one of (i) a movement component which corresponds to an oscillating pivoting movement of the machining tool (3) about a pivot axis, said pivot axis being transverse or at right angles or parallel to an axis of rotation (13) of the workpiece (15), or (ii) at least one movement component which corresponds to a liner movement of the machining tool (3) in a plane which is parallel or at right angles to, or oblique in relation to, the axis of rotation (13) of the workpiece (15).

3. The method as claimed in claim 1, wherein the at least one pivot axis (7) of the oscillating additional movement of the cutting edge (4) of the machining tool (3) is oriented transversely or at right angles or parallel to the axis of rotation (13) of the workpiece (15).

4. A tool head (1) for a lathe (2), comprising a tool holder (5) retaining a machining tool (3), at least one actuator (6) that generates an additional movement of the tool holder (5) in the form of an oscillating pivoting movement about at least one pivot axis (7).

5. The tool head (1) as claimed in claim 4, wherein the at least one actuator (6) is configured to generate an oscillating linear displacement movement, and wherein the tool head (1) further comprises a device (8) that converts the oscillating linear displacement movement into the oscillating pivoting movement of the tool holder (5).

6. The tool head (1) as claimed in claim 5, wherein the at least one actuator (6) for generating the oscillating linear displacement movement is arranged such that the oscillating linear displacement movement takes place along a spatial axis or in a direction which is arranged transversely or at right angles to the at least one pivot axis (7) of the tool holder (5).

7. The tool head (1) as claimed in claim 5, wherein the device (8) for converting the oscillating linear displacement movement into the oscillating pivoting movement includes a flexible coupling (9) having a first end (10) that is connected to a driven element (11) of the at least one actuator (6) and a second end (12) arranged opposite the first end that is connected to the tool holder (5).

8. The tool head (1) as claimed in claim 4, wherein, when the tool head (1) is in a use position on a lathe (2), the at least one pivot axis (7) of the oscillating pivoting movement of the tool holder (5) is adapted to be oriented transversely or at right angles or parallel to an axis of rotation (13) of an operating spindle (14) of the lathe (2) in order to drive a workpiece (15) which is to be machined.

9. The tool head (1) as claimed in claim 4, wherein the pivoting movement of the tool holder (5) comprises a first pivoting-movement component about a first pivot axis (7) and a second pivoting-movement component about a second pivot axis, and the first pivot axis is oriented transversely or at right angles to the second pivot axis.

10. The tool head (1) as claimed in claim 4, wherein the tool head (1) is pivotable in oscillation about a pivot axis (16) which is oriented transversely or at right angles or parallel to the at least one pivot axis (7) of the tool holder (5), or, when in a use position on a lathe (2), the tool head (1) can be pivoted about a pivot axis (16) which is oriented transversely or at right angles or parallel to an axis of rotation (13) of an operating spindle (14) of the lathe (2) for a workpiece (15) which is to be machined, or in the use position on the lathe (2), the tool head (1) is displaceable in a plane which is parallel or at right angles to, or oblique in relation to, the axis of rotation (13) of the operating spindle (14).

11. The tool head (1) as claimed in claim 4, wherein the oscillating pivoting movement of the tool holder (5) corresponds to an oscillating rotation or pivoting movement of the tool holder (5) through less than 10 degrees in both turning directions.

12. The tool head (1) as claimed in claim 4, wherein an oscillation frequency of the oscillating pivoting movement of the tool holder (5) is greater than a turning frequency, relative to the machining tool (3), of a workpiece (15) which is to be machined, or the oscillation frequency of the oscillating pivoting movement of the tool holder (5) is greater than an oscillation frequency of the pivoting movement of the tool head (1) about a pivot axis (16) thereof.

13. The tool head (1) as claimed in claim 4, wherein an oscillation frequency of the oscillating pivoting movement of the tool holder (5) is coordinated with a turning frequency, relative to the machining tool (3), of a workpiece (15) which is to be machined.

14. The tool head (1) as claimed in claim 4, wherein the at least one actuator (6) comprises a piezoelectric actuator.

15. The tool head (1) as claimed in claim 4, wherein the tool head (1) is releasably fastenable on a tool turret (17) of a lathe (2) using a releasable coupling (18) of the tool head (1).

16. The tool head (1) as claimed in claim 4, wherein the cutting edge (4) of the machining tool (3) has a helix form which is coaxial in relation to a pivot axis (16) of the tool head (1).

17. A lathe (2) having an operating spindle (14) for driving in rotation a workpiece (15) which is to be machined by turning, having a tool turret (17), and having at least one tool head (1) as claimed in claim 4 fitted on the tool turret (17).

18. The lathe (2) as claimed in claim 17, wherein the tool turret (17) generates a relative movement between the at least one tool head (1) and the workpiece (15), the relative movement corresponds to at least one of an oscillating pivoting movement of the tool head (1) about a pivot axis (16) which is oriented transversely or at right angles or parallel to the axis of rotation (13) of the operating spindle (14) and of the workpiece (15), or corresponds to a linear advancement movement in a plane which is oblique in relation to, or parallel or at right angles to, the axis of rotation (13) of the operating spindle (14) and of the workpiece (15).

19. A method for machining a workpiece (15) using the lathe according to claim 17, the method comprising: driving the workpiece (15) in rotation in order to generate a cutting movement, bringing the cutting edge (4) of the machining tool (3) into cutting engagement with the workpiece (15) by an advancement movement that includes an oscillating additional movement of the cutting edge (4) of the machining tool (3), and the oscillating additional movement of the cutting edge (4) of the machining tool (3) is an oscillating pivoting movement about at least one pivot axis (7).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] An exemplary embodiment of the invention will be described herein-below with reference to the drawings, in which, in in some cases highly schematic illustrations:

[0042] FIG. 1 shows a perspective view of a tool head according to the invention,

[0043] FIG. 2 shows a side view of the tool head illustrated in FIG. 1,

[0044] FIG. 3 shows a side view of the tool head according to the invention illustrated in FIGS. 1 and 2, this side view being taken in section along section line A to A depicted in FIG. 2, and

[0045] FIG. 4 shows a highly schematic illustration of an embodiment of a lathe according to the invention in order to depict the relative positions of the pivot axes of the machining tool and of the tool holder, of the pivot axis of the tool head and of the axes of rotation of the workpiece and of the operating spindle.

DETAILED DESCRIPTION

[0046] All the figures show a tool head which is designated as a whole by 1 and is intended for a lathe 2, which is illustrated only in highly schematic fashion in FIG. 4. The tool head 1 is provided with a machining tool 3, which has a cutting edge 4. The machining tool 3 is retained by a tool holder 5 of the tool head 1. The tool head 1 has an actuator 6, which is intended for generating a movement, more precisely an additional movement, in the form of an oscillating pivoting movement of the tool holder 5 about a pivot axis 7.

[0047] It is clear from FIG. 3 that the actuator 6 is designed for generating an oscillating linear displacement movement, and that the tool head 1 has a device 8 for converting this oscillating linear displacement movement into the oscillating pivoting movement of the tool holder 5. According to FIGS. 3 and 4, the actuator 6 for generating the oscillating linear displacement movement is arranged such that the oscillating linear displacement movement takes place along a spatial axis or in a direction which is arranged transversely, and in the present exemplary embodiment of the tool head 1 according to the invention even at right angles, to the pivot axis 7 of the tool holder 5.

[0048] The device 8 for converting the oscillating linear displacement movement into the oscillating pivoting movement is formed by a flexible coupling 9. This flexible coupling 9, at a first end 10, is connected to a driven element 11, for example a push rod, of the actuator 6 and, at a second end 12, which is arranged opposite the first end 10, is connected to the tool holder 5. The flexible coupling 9 here is at a radial spacing from the pivot axis 7 of the tool holder 5.

[0049] When the tool head 1 is in the use position on the lathe 2, as illustrated in FIG. 4, the pivot axis 7 of the oscillating pivoting movement of the tool holder 5 is oriented parallel to an axis of rotation 13 of an operating spindle 14, which can drive a workpiece 15 which is to be machined. It should be pointed out here that the axis of rotation 13 of the operating spindle 14 coincides with the axis of rotation of the workpiece 15.

[0050] In the case of that exemplary embodiment of the tool head 1 according to the invention which is illustrated in the figures, the pivoting movement of the tool holder 5 comprises merely a pivoting-movement component which takes place about the already above-described pivot axis 7. In the case of another exemplary embodiment of the tool head 1 according to the invention, which is not illustrated in the figures, this pivoting movement can comprise a first pivoting-movement component about a first pivot axis and a second pivoting-movement component about a second pivot axis. The first pivot axis here is oriented transversely or at right angles to the second pivot axis.

[0051] It is clear in particular from the illustration of the tool head 1 according to the invention in FIG. 4 that the tool head 1 can also be pivoted in oscillation about a pivot axis 16. In the case of the exemplary embodiment of the invention which is illustrated in FIG. 4, this pivot axis 16 is oriented parallel to the pivot axis 7 of the tool holder 5 and also parallel to the axis of rotation 13 of the operating spindle 14 of the lathe 2. In the case of another exemplary embodiment of the invention, which is not illustrated in the figures, provision is made for the tool head 1 to be pivotable in oscillation about a pivot axis which is oriented transversely or at right angles to the pivot axis 7 of the tool holder 5. It is then possible for the pivot axis 16 of the tool head 1 to be oriented optionally transversely or at right angles or parallel to the axis of rotation 13 of the operating spindle 14 of the lathe 2 for the workpiece 15 which is to be machined. In addition, or as an alternative, to this, it is possible, when it is in its use position on the lathe 2, for the tool head 1 to be displaceable in a plane which is parallel or also at right angles to, or oblique in relation to, the axis of rotation 13 of the operating spindle 14. This makes it possible to predetermine a wide variety of different advancement movements for machining the workpiece 15.

[0052] The oscillating pivoting movement of the tool holder can correspond to an oscillating rotation or pivoting movement of the tool holder 5 through less than 10, preferably through 5, in particular through less than 1, in both turning directions or pivoting directions.

[0053] The oscillation frequency of the oscillating pivoting movement of the tool holder 5 here is greater than a turning frequency, relative to the machining tool 3, of the workpiece 15 which is to be machined. The oscillation frequency of the oscillating pivoting moment of the tool holder 5 is also greater than an oscillation frequency of the pivoting movement of the tool head 1 about its pivot axis 16.

[0054] The oscillation frequency of the oscillating pivoting movement of the tool holder 5 can be coordinated with the turning frequency, relative to the machining tool 3, of the workpiece 15 which is to be machined.

[0055] The actuator 6 of the tool head 1 is formed by a piezoelectric actuator. Such an actuator is distinguished by its low-level energy requirement.

[0056] The tool head 1 can be fastened in a releasable manner on a tool turret 17 of the lathe 2. For this purpose, the tool head 1 has a releasable coupling 18, which is designed in the form of a plug-in coupling and by means of which the tool head 1 can be connected in a releasable manner to the tool turret 17 of the lathe 2. In the case of an exemplary embodiment of the tool head 1 according to the invention which is not illustrated in the figures, the cutting edge 4 of the machining tool 3 is in the form of a helix. It is possible for the latter to be coaxial in relation to the pivot axis 16 of the tool head 1 and to have a pitch with a pitch angle between 0 and 90, preferably between 15 and 45.

[0057] In addition to the at least one tool head 1 according to the invention, the lathe 2 can accommodate further tool heads 1 according to the invention, or else also other tool heads, on its tool turret 17.

[0058] The lathe 2 may also be intended for generating a relative movement between the at least one tool head 1 according to the invention and the workpiece 15. This relative movement, which is responsible at least for part of the advancement movement for the purpose of turning the workpiece 15, corresponds to the oscillating pivoting movement of the tool head 1 about the pivot axis 16, which is oriented transversely, at right angles or also parallel to the axis of rotation 13 of the operating spindle 14 and of the workpiece 15. In addition, it is possible for the lathe 2, and in particular the tool turret 17 of the lathe 2, also to be intended for carrying out a linear advancement movement in a plane which is oblique in relation to, or parallel or at right angles to, the axis of rotation 13 of the operating spindle 14 and of the workpiece 15.

[0059] The lathe 2 is intended for implementing the method described herein-below for machining the workpiece 15 with the aid of the material-removing machining tool 3 having at least one cutting edge 4:

[0060] The workpiece 15 here is driven in rotation in order to generate a cutting movement, with the aid of the operating spindle 14 of the lathe 2, and the cutting edge 4 of the machining tool 3 is brought into cutting engagement with the workpiece 15. In addition, the machining tool 3 is moved by a defined advancement movement relative to the workpiece 15. The advancement movement is then accompanied by an oscillating additional movement of the cutting edge 4 of the machining tool 3. The oscillating additional movement of the cutting edge 4 of the machining tool 3 here is an oscillating pivoting movement about the pivot axis 7.

[0061] The advancement movement of the machining tool 3 comprises a movement component which corresponds to an oscillating pivoting movement of the machining tool 3 about a pivot axis, in this case about the pivot axis 16 of the tool head. In the exemplary embodiment illustrated in the figures, this pivot axis 16 is oriented parallel to the axis of rotation 13 of the workpiece 15 and of the operating spindle 14 of the lathe 2. Depending on requirements, it is also possible for the advancement movement of the machining tool 3 to comprise at least one movement component which corresponds to a liner movement of the machining tool 3 in a plane which is parallel or at right angles to, or oblique in relation to, the axis of rotation 13 of the workpiece 15 and of the operating spindle 14. As already described in detail above, the pivot axis 7 of the oscillating additional movement of the cutting edge 4 of the machining tool 3 can be oriented transversely or at right angles or also parallel to the axis of rotation 13 of the workpiece 15 and of the operating spindle 14.

[0062] The invention proposes, in addition to a method for machining the workpiece 15 and to the lathe 2, in particular also the tool head 1 for the lathe 2, having the tool holder 5 retaining the machining tool 3, wherein the tool head 1 has the at least one actuator 6 for generating the additional movement of the tool holder 5 in the form of an oscillating pivoting movement about the at least one pivot axis 7.

LIST OF REFERENCE SIGNS

[0063] 1 Tool head

[0064] 2 Lathe

[0065] 3 Machining tool

[0066] 4 Cutting edge

[0067] 5 Tool holder

[0068] 6 Actuator

[0069] 7 Pivot axis of 5

[0070] 8 Device for converting the oscillating linear displacement movement into the oscillating pivoting movement

[0071] 9 Flexible coupling

[0072] 10 First end of 9

[0073] 11 Driven element

[0074] 12 Second end of 9

[0075] 13 Axis of rotation of 14/15

[0076] 14 Operating spindle

[0077] 15 Workpiece

[0078] 16 Pivot axis of the tool head

[0079] 17 Tool turret

[0080] 18 Coupling of the tool head