Machine tool

Patent metadata

Field	Value
Publication number	US-9849555-B2
Application number	US-201615332844-A
Country	US
Kind code	B2
Filing date	Oct 24, 2016
Priority date	Nov 4, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A machine tool includes a stationary machine frame, a tool head, which is able to be positioned relative to the machine frame along three mutually orthogonal translation axes, and a motor-driven tool. The machine tool includes a swivel unit, which can be pivoted about a horizontal swivel axis relative to the machine frame and includes a workpiece positioning device, via which a workpiece can be rotated about an axis of rotation oriented perpendicularly to the swivel axis. The swivel unit is assigned a measuring frame, which is able to be rotated with the swivel unit and is arranged to be thermally and/or mechanically decoupled from the swivel unit and includes components of a first and second position measuring system. Additional components of the first position measuring system are disposed on the tool head, and further components of the second position measuring system are situated on the workpiece positioning device. The spatial position of the tool head in relation to the measuring frame is ascertained via the first position measuring system, and the spatial position of the workpiece positioning device in relation to the measuring frame takes place via the second position measuring system.

First claim

What is claimed is:

1. A machine tool, comprising
a stationary machine frame;
a tool head positionable relative to the machine frame along three translation axes oriented orthogonally with respect to each other, the tool head including a motor-driven tool;
a swivel unit pivotable about a horizontal swivel axis relative to the machine frame and including a workpiece positioning device adapted to rotate a workpiece about an axis of rotation oriented perpendicularly to the swivel axis;
a first measuring system;
a second measuring system; and
a measuring frame assigned to the swivel unit, the measuring frame rotatable with the swivel unit and thermally and/or mechanically decoupled from the swivel unit, components of the first measuring system and the second measuring system being provided on the measuring frame;
wherein additional components of the first position measuring system are arranged on the tool head, and further components of the second position measuring system are provided on the workpiece positioning device;
wherein the first position measuring system is adapted to measure a spatial position of the tool head relative to the measuring frame; and
wherein the second position measuring system is adapted to measure a spatial position of the workpiece positioning device relative to the measuring frame.

2. The machine tool according to claim 1 , wherein the measuring frame is integrated into the swivel unit and connected via multiple flexible elements.

3. The machine tool according to claim 1 , wherein the measuring frame is arranged such that a pose of the first and second position measuring systems with respect to each other does not change during operation of the machine tool.

4. The machine tool according to claim 1 , wherein at least a portion of the measuring frame is arranged in an L-shape, a first leg of the measuring frame extending in parallel with the swivel axis and a second leg of the measuring frame extending in parallel with the axis of rotation.

5. The machine tool according to claim 1 , wherein a thermal zero point of the measuring frame is located on the axis of rotation of the workpiece positioning device.

6. The machine tool according to claim 1 , wherein the second position measuring system includes a drum-shaped measuring standard and at least three scanning heads adapted to scan the measuring standard;
wherein the measuring standard is arranged on the workpiece positioning device, a longitudinal axis of the drum coinciding with the axis of rotation of the workpiece positioning device; and
wherein the scanning heads are arranged on the measuring frame distributed around a circumference of the drum.

7. The machine tool according to claim 6 , wherein the measuring standard is arranged as an incident light measuring standard that includes alternate scale graduation regions in radial and axial directions having different optical characteristics; and
wherein the scanning heads are adapted to optically scan the measuring standard, each scanning head including at least one light source and a detector device.

8. The machine tool according to claim 1 , wherein the first position measuring system includes at least one optical transmitter unit and an optical receiver unit; and
wherein (a) the transmitter unit is arranged on the tool head and the receiver unit is arranged on the measuring frame, or (b) the transmitter unit is arranged on the measuring frame and the receiver unit is arranged on the tool head, or (c) the transmitter unit and the receiver unit are arranged on the measuring frame and a reflector unit is arranged on the tool head, or (d) the transmitter unit and the receiver unit are arranged on the tool head and a reflector unit is arranged on the measuring frame.

9. The machine tool according to claim 8 , further comprising shielding elements arranged between the tool head and the measuring frame, the shielding elements adapted to shield beam bundles from the first position measuring system propagating between the tool head and the measuring frame.

10. The machine tool according to claim 8 , wherein the tool head includes at least one position sensor adapted to ascertain a position of a motor shaft driving the tool relative to a housing of the tool head on which the components of the first position measuring system are arranged.

11. The machine tool according to claim 8 , wherein the transmitter unit includes at least three light sources arranged in a fixed relative position relative to each other and temporally activatable in a selective manner by a control and evaluation device.

12. The machine tool according to claim 11 , wherein the receiver unit includes at least one optoelectronic detector system and at least one scanning grating arranged upstream from the detector system.

13. The machine tool according to claim 12 , wherein the control and evaluation device is adapted to ascertain an angular position of an activated light source relative to the detector system based on a position of a fringe pattern that results on the detector system, so that a spatial position of the tool is ascertainable following a sequential activation of the at least three light sources.

14. The machine tool according to claim 8 , wherein the first position measuring system includes an actively or passively tracking interferometer, having transmitter and receiver units arranged on the measuring frame and a reflector unit arranged on the tool head, the reflector unit including at least one retroreflector, and the transmitter unit including a tracking mechanism for at least six measuring beam bundles adapted to adjust the beam bundles to the retroreflector.

15. The machine tool according to claim 14 , wherein the retroreflector is arranged as a measuring reflector, the interferometer adapted to measure a distance between the measuring reflector and a stationary reference reflector, the measuring reflector and the reference reflector being spherical.

Assignees

• Heidenhain Gmbh Dr Johannes

Inventors

• Meissner Markus

Classifications

• B23C1/14

  with rotary work-carrying table (work tables for machine tools in general B23Q1/00) · CPC title

• B23C1/002

  Gantry-type milling machines · CPC title

• B23Q17/2428 Primary

  for measuring existing positions of tools or workpieces · CPC title

• B23Q17/2404

  Arrangements for improving direct observation of the working space, e.g. using mirrors or lamps (structural combinations of lighting devices with other articles, not otherwise provided for, F21V33/00) · CPC title

• B23C2260/76

  Sensors · CPC title