SPINDLE APPARATUS FOR USE ON A NUMERICALLY CONTROLLED MACHINE TOOL

Abstract

The present invention relates to a spindle apparatus 100 for use on a numerically controlled machine tool, which spindle apparatus 100 has the following: a spindle housing 1, and a spindle shaft 15 which is mounted in the spindle housing, the spindle apparatus 100 having, furthermore, an electrically earthed section 4 which holds at least one rod element 20 which comprises an electrically conductive material, and the at least one rod element 20 being arranged in such a way that it makes contact with the spindle shaft 15 so as to bear tangentially against an outer circumference of the spindle shaft 15.

Claims

1. Spindle apparatus for use on a numerically controlled machine tool, having: a spindle housing, and a spindle shaft which is mounted in the spindle housing, the spindle apparatus having, furthermore, an electrically earthed section which holds at least one rod element which comprises an electrically conductive material, and the at least one rod element being arranged in such a way that it makes contact with the spindle shaft so as to bear tangentially against an outer circumference of the spindle shaft.

2. Spindle apparatus according to claim 1, characterized in that the at least one rod element is configured as a carbon fiber rod element.

3. Spindle apparatus according to claim 1, characterized in that the electrically earthed section of the spindle apparatus and a receiving apparatus for receiving tools and/or workpieces on an end side of the spindle shaft are provided.

4. Spindle apparatus according to claim 3, characterized in that, furthermore, a sensor device is provided on the end side of the spindle shaft, which sensor device has, in particular, at least one vibration sensor for detecting vibrations and/or a structure-borne sound sensor for detecting structure-borne sound waves or vibrations.

5. Spindle apparatus according to claim 1, characterized in that the electrically earthed section is of partially annular, annular or hollow-cylindrical configuration, the spindle shaft extending through an internal diameter of the electrically earthed section.

6. Spindle apparatus according to claim 1, characterized in that the electrically earthed section has at least one bore, in which the rod element is held in the electrically earthed section.

7. Spindle apparatus according to claim 6, characterized in that the bore, in which the rod element is held, is of secant-shaped configuration in the electrically earthed section, in such a way that the rod element which is held in the bore makes contact with the spindle shaft in a tangentially bearing manner.

8. Spindle apparatus according to claim 1, characterized in that the electrically earthed section holds at least two rod elements, and each rod element makes contact with the spindle shaft in each case as to bear tangentially against the outer circumference of the spindle shaft.

9. Spindle apparatus according to claim 8, characterized in that the normals of the rod elements which make contact tangentially with the outer circumference of the spindle shaft lie at an angle of from 45 to 135 with respect to one another.

10. Spindle apparatus according to claim 1, characterized in that the at least one rod element makes contact with the spindle shaft so as to bear tangentially under an elastic deformation.

11. Spindle apparatus according to claim 1, characterized in that the spindle apparatus has at least one resilient element for each rod element, which resilient element presses the respective rod element onto the outer circumference of the spindle shaft.

12. Spindle apparatus according to claim 11, characterized in that, furthermore, the resilient element has a thread-shaped setting apparatus, by means of which the force which presses the rod element onto the outer circumference of the spindle shaft can be set.

13. Spindle apparatus according to claim 1, characterized in that the rod element has a sleeve in each case at the two ends, which sleeve is in contact with the electrically earthed section in a flatly bearing manner.

14. Spindle apparatus according to claim 13, characterized in that at least one sleeve on each rod element has a thread for fastening the rod element in the electrically earthed section.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0043] FIG. 1 shows an exemplary diagrammatic perspective exploded illustration of a spindle apparatus for a numerically controlled machine tool, which spindle apparatus has a sensor system device,

[0044] FIG. 2 shows an exemplary diagrammatic illustration of a spindle apparatus for a numerically controlled machine tool in a side view and a sectional view in accordance with one exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE FIGURES AND PREFERRED EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

[0045] In the following text, examples and exemplary embodiments of the present invention will be described in detail with reference to the appended figures. Here, identical or similar elements in the figures can be denoted by identical reference numerals, but sometimes also by different reference numerals.

[0046] It is to be emphasized that the present invention is not limited or restricted in any way to the exemplary embodiments which are described in the following text and their embodiment features, but rather also includes modifications of the exemplary embodiments, in particular those which are included within the scope of protection of the independent claims as a result of modifications of the features of the described examples and/or by way of combination of single or multiple features of the described examples.

[0047] FIG. 1 shows an exemplary diagrammatic perspective exploded illustration of a spindle apparatus 100 for a numerically controlled machine tool (not shown), which spindle apparatus 100 has a sensor system device.

[0048] In particular, FIG. 1 shows an exemplary diagrammatic perspective exploded illustration of parts of a spindle apparatus 100 of a working spindle, in particular of a tool-carrying working spindle, for a numerically controlled machine tool (not shown).

[0049] The machining unit which is shown by way of example and has a working spindle or spindle apparatus 100 is set up, for example, to carry out milling and/or drilling work on workpieces which are clamped on workpiece clamping means of the machine tool, for example with the use of tools (not shown in FIG. 1), in particular milling and drilling tools which can usually be clamped on the spindle shaft or spindle apparatus with the use of tool interfaces which can be interchanged on the spindle shaft, and are then driven rotationally at high rotational speeds by way of the spindle shaft or spindle apparatus in order to generate or to drive the cutting movement.

[0050] One or more of the machining units having a spindle shaft or spindle apparatuses 100 of a working spindle can be provided, for example, for machining or manufacturing workpieces for or on the machine tools, in particular on program-controlled or numerically controllable machine tools, such as milling machines, milling machines/lathes, universal milling machines, universal machine tools or CNC machining centres which have one or more tool-carrying working spindles.

[0051] Tools can typically be received on spindle shafts of this type on receiving apparatuses or tool receptacles of the spindle shafts by way of tool interfaces, such as tool cones, in particular Morse tapers, steep angle tapers or hollow shaft cones, in order then to be driven on the working spindle. They can be a very wide variety of drilling or milling tools or other tools which are each clamped or fixed on the typically standardized tool interface or the tool cone.

[0052] The machining unit/spindle apparatus 100 in accordance with FIG. 1 comprises, by way of example, a spindle housing 1 which can be fastened to a further component of the machine tool or can be assembled with the latter, in particular by way of a spindle head carrier or a swivel head of the machine tool, to be precise optionally with the aid of an annular flange 2 which has a multiplicity of axial bores 3 for fastening to or assembling with further components of the machine tool. The spindle shaft 15 is mounted rotatably in the interior of the housing 1.

[0053] By way of example, a frustoconical housing part 4 (electrically earthed section) of the machining unit/spindle apparatus 100 is fastened to the front side of the annular flange 2, in the circumferential wall of which frustoconical housing part 4 one (or more) outwardly open longitudinal groove/grooves 5 is/are machined by way of example. The longitudinal groove 5 is continued by way of example in a receiving groove 6 which is configured by way of example in the annular flange 2. The longitudinal groove 5 and its continuation, that is to say, for example, the receiving groove 6, by way of example form a receiving channel for a power and/or measured data cable (not shown in FIG. 1) which is laid in the said receiving channel 5, 6 and can subsequently be covered by way of a shaped metal sheet 7 which is fastened releasably to the housing part 4.

[0054] In front of the front end of the housing part 4, FIG. 1 shows by way of example a first ring element 10 which can be fastened releasably to the end side of the housing part 4, by way of example by way of a plurality of fastening elements 11 (for example, threaded bolts). The first ring element 10 has, by way of example, a profiled cross section and is supported, by way of example, with its right-hand (in FIG. 1) end face (that is to say, in particular, with the side which faces the spindle), on the left-hand annular end face of the housing part 4 or is attached on the latter or fastened releasably to the latter.

[0055] At the front end of the spindle shaft 15, a second ring element 16 is fastened releasably to the first ring element 10 by way of a plurality of fastening means (for example, stud bolts), the second ring element 16 rotating together with the spindle shaft 15 and being capable of providing a rotor as a consequence.

[0056] The second ring element 16 has, by way of example, a cylindrical inner circumferential face and, by way of example, a stepped cross section. The second ring element 16 is covered, by way of example, by way of an annular covering element 17 which is fastened releasably to the, by way of example, planar end face of the spindle in planar contact with the aid of fastening means (for example, stud bolts 18), and closes off the spindle shaft with the exposure of the tool receptacle for clamping in a tool shank on the end side.

[0057] By way of example, receiver and/or transmission means can be accommodated in the first ring element 10, which receiver and/or transmission means can serve for the contactless transmission of measured data, sensor signals and/or power signals. Furthermore, by way of example, a cable passage section 12 for the electric connection to the sensor system is provided on the first ring element 10 (for example, connection of the power and/or measuring cable to the receiver and/or transmission means), which cable passage section 12 lies opposite the cable channel of the longitudinal groove 5 and can protrude into the said cable channel in the mounted state.

[0058] One or more sensors can be accommodated in the second ring element 10. These can comprise, for example, sensors, for example vibration sensors, by way of which operation-related deformations of the spindle and/or the spindle head in the axial direction and also in the circumferential direction can be detected. Different sensor types, for example sensors which are sensitive to pressure, stress or force, are suitable as sensing elements, in order to detect, for example, misalignments of the spindle and/or shape changes.

[0059] The sensor system possibly comprises an evaluation unit which is coupled electronically to the different sensors, performs an evaluation and also storage of the detected data, and can be controlled by microprocessor. The wear values of the cutting tools and possible damage of machine components as a result of impact collisions can also be detected, stored and correspondingly taken into consideration in the machine controller with the aid of the said sensor system. Furthermore, it is possible by way of vibration sensors to carry out unbalanced measurements and/or to detect bearing damage of bearings of the spindle shaft on the basis of an evaluation of the measured signals.

[0060] A cable (measuring and/or power cable) is laid in the cable channel 5 of the housing part 4 as far as into the stationary outer ring (first ring element 10) which is connected fixedly to the spindle housing part 4. Connectors for the power and measured data cable are possibly situated in the said outer ring (first ring element 10), it also being possible for the said power or measuring cable to be connected to a transmission element which is arranged in the stationary outer ring (first ring element 10), and the counter-element (receiver element) of which can be situated in the rotor ring (second ring element 16) which rotates with the spindle.

[0061] The above-described spindle apparatus 100 is to be understood merely as an example for a spindle apparatus, as is currently state of the art and for which purpose a sensor system is used in or on the spindle shaft 15. A different spindle apparatus 100 can however also indeed have different components and sensors and can detect different or further parameters for monitoring the machining process. The embodiments of the described invention can be applied on the above-described spindle apparatus 100 and also on different spindle apparatus is which are not described here in detail.

[0062] FIG. 2 shows an exemplary diagrammatic illustration of a spindle apparatus 100 for a numerically controlled machine tool (not shown) in a side view and a sectional view in accordance with one exemplary embodiment of the present invention.

[0063] Here, by way of example, two rod elements 20 can be seen in the sectional view, which rod elements 20 have, in each case at one end, a sleeve 21 with a conically tapering end and a thread 22 which can also be applied on a sleeve and can then be pressed onto the rod element. However, the thread 22 can also be replaced by a threaded pin or by a screw, depending on the application and installation space.

[0064] Here, as planar a contact as possible is to be produced between 8 rod element 20 and housing part 4 (electrically earthed section) by way of the sleeves 21 which are used. Only this can ensure that even high potential spikes can be discharged from the spindle shaft 15 and cannot damage or overload the surrounding material in the process. In addition, a planar contact of the sleeve/sleeves 21 affords the advantage that rattling of the rod element 20 can be reduced or avoided. Furthermore, a conically tapering end of the sleeve 21 (as shown in FIG. 2) is advantageous in so far as, during the insertion of the rod element 20 into the spindle apparatus 100, the risk of tilting of the rod element 20 in the housing part 4 or on the spindle shaft 15 can be reduced. This facilitates the mounting of the rod elements 20 to a considerable extent.

[0065] The thread 22 or a threaded pin or a screw secures the rod element 20 against movement within the spindle apparatus 100. Furthermore, rattling of the rod element 20 within the spindle apparatus 100 can be reduced or avoided by way of the securing using a thread 22.

[0066] In addition, it can be seen in the sectional view of FIG. 2 how, by way of example, a resilient element 25 is provided on each rod element 20, in order to press the respective rod element 20 onto the spindle shaft 15 with an increased force.

[0067] This ensures that the rod element 20 remains reliably in contact with the spindle shaft 15 even in the case of pronounced vibrations which occur during the workpiece machining.

[0068] That force of the resilient element 25 which acts on the rod element 20 can advantageously be set by way of a thread-shaped setting apparatus, furthermore. The pressing force of the rod element 20 on the spindle shaft 15 can thus be increased or decreased in a very precisely metered manner. In addition, the setting by way of the thread shape can take place in an infinitely variable manner and does not require any additional securing means in most cases. A further advantage in the case of the use of a thread on the resilient element 25 is that the resilient element 25 can be dismantled very easily in the case of a replacement of the rod element 20, and can also be inserted again easily after the replacement of the rod element 20.

[0069] In the above text, examples and exemplary embodiments of the present invention and their advantages have been described in detail with reference to the appended figures.

[0070] It is to be emphasized again that the present invention is not limited or restricted in any way at all, however, to the above-described exemplary embodiments and their embodiment features, but rather comprises, furthermore, modifications of the exemplary embodiments, in particular those which are included within the scope of protection of the independent claims by way of modifications of the features of the described examples and/or by way of combination of single or multiple features of the described examples.

LIST OF REFERENCE NUMERALS

[0071] 1 Spindle housing

[0072] 2 Annular flange

[0073] 3 Axial bore

[0074] 4 Electrically earthed section/housing part

[0075] 5 Open longitudinal groove

[0076] 6 Receiving groove

[0077] 7 Shaped metal sheet

[0078] 10 First ring element

[0079] 11 Fastening plate

[0080] 12 Cable passage section

[0081] 15 Spindle shaft

[0082] 16 Second ring element

[0083] 17 Annular covering element

[0084] 18 Stud bolts

[0085] 20 Rod element

[0086] 21 Sleeve

[0087] 22 Thread of the rod element

[0088] 25 Resilient element

[0089] 100 Spindle apparatus