TOOL HOLDER WITH MEASURING APPARATUS

Abstract

A tool holder is configured for rotation about a tool holder axis of rotation defining an axial direction. The tool holder, at one axial longitudinal end thereof, has a tool section with a tool-receiving formation for receiving a tool and, at the opposite axial longitudinal end, has a coupling section with a coupling formation for torque-transmitting coupling to a machine spindle of a machine tool. A measuring apparatus is configured for acquiring data relating to the operation of the tool holder. The measuring apparatus has a sensor, in particular an acceleration sensor, with at least two measurement axes. The two measurement axes are oriented substantially radially with respect to the tool holder axis of rotation.

Claims

1. A tool holder configured for rotation about a tool holder axis of rotation defining an axial direction, the tool holder comprising: a first axial longitudinal end having a tool section with a tool-receiving formation for receiving a tool; a second axial longitudinal end having a coupling section with a coupling formation for torque-transmitting coupling to a machine spindle of a machine tool; a measuring apparatus for acquiring data relating to an operation of the tool holder, said measuring apparatus having a sensor with at least two measurement axes that are oriented substantially radially with respect to the tool holder axis of rotation.

2. The tool holder according to claim 1, wherein said sensor is an acceleration sensor having two or more measurement axes.

3. The tool holder according to claim 1, wherein said sensor has two measurement axes which are oriented orthogonally with respect to one another.

4. The tool holder according to claim 1, wherein said sensor has three measurement axes which are oriented orthogonally with respect to one another and which span an orthogonal coordinate system, with a third of the measurement axes being oriented substantially axially with respect to the tool holder axis of rotation.

5. The tool holder according to claim 1, further comprising electronics components selected from the group consisting of a microcontroller, one or more transmission devices, one or more antennae, one or more circuit boards, and one or more energy supplies.

6. The tool holder according to claim 5, wherein said sensor is arranged on a separate circuit board and said microcontroller is supported on a circuit board that is different from said circuit board supporting said sensor.

7. The tool holder according to claim 6, wherein said circuit board bearing said microcontroller is configured as a flexible circuit board, and/or wherein said one or more transmission devices or antennae are or is arranged on one or more separate circuit boards.

8. The tool holder according to claim 5, wherein said antenna is a surface mounted device antenna or a wire antenna.

9. The tool holder according to claim 5, wherein said antenna is arranged on a separate circuit board or is a self-adhesive foil antenna.

10. The tool holder according to claim 1, wherein the tool holder has an outer surface formed with a depression and said a transmission device and/or an energy supply is recessed in said depression.

11. The tool holder according to claim 10, wherein said depression is a circular pocket on the outer surface of the tool holder, and said depression is potted and/or covered.

12. The tool holder according to claim 10, wherein said depression is a circular pocket that is potted with a silicone compound.

13. The tool holder according to claim 1, further comprising two or more transmission devices distributed in a circumferential direction about the tool holder axis of rotation.

14. The tool holder according to claim 1, wherein the tool holder is formed with one or more connection bores running obliquely with respect to the tool holder axis of rotation.

15. The tool holder according to claim 1, wherein said the sensor has an SPI interface and/or electronics in the tool holder have SPI interfaces and/or an SPI bus.

16. The tool holder according to claim 1, further comprising an energy supply being a kinetic, energy harvesting energy supply embodied by a coolant flow in the tool holder.

17. The tool holder according to claim 1, wherein said sensor is arranged in the tool holder axis of rotation or in close vicinity to the tool holder axis of rotation.

18. The tool holder according to claim 1, wherein said tool-receiving formation is a device selected from the group consisting of a shrink chuck, a hydraulic expansion chuck, a face mill arbor, a collet chuck, and a power chuck.

19. The tool holder according to claim 1, wherein said coupling formation comprises a hollow shaft cone or a steep-angle taper and/or an engagement formation for a ball-type clamping system or a polygonal hollow shaft.

20. A machine tool, comprising a tool holder according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0069] FIG. 1 shows a tool holder with clamping chuck (in this case shrink chuck) according to one embodiment;

[0070] FIG. 2 shows a part of the tool holder as per FIG. 1 with battery compartment and antenna pocket;

[0071] FIG. 3 shows a view of the tool holder as per FIG. 1 with a position of the (flexible) main board;

[0072] FIG. 4 shows a (flexible) main board with protective foil on the front and rear sides and with a sensor connection, microcontroller (μC) and antenna connection for the tool holder as per FIG. 1;

[0073] FIG. 5 shows the (flexible) main board with sensor connection (plug contacts), microcontroller (μC), antenna connection, programming contacts and energy supply connection (plug contacts) for the tool holder as per FIG. 1;

[0074] FIG. 6 shows a view of the tool holder as per FIG. 1 with a position of the sensor;

[0075] FIG. 7 shows a sensor board with the sensor and with wiring for the tool holder as per FIG. 1;

[0076] FIG. 8 shows the sensor board with the sensor and the (flexible) main board wired for the tool holder as per FIG. 1;

[0077] FIG. 9 shows a tool holder with clamping chuck (in this case shrink chuck) according to a further embodiment with two wire antennae;

[0078] FIG. 10 shows processing/sensor data of a tool holder with a uniaxial acceleration sensor;

[0079] FIG. 11 shows processing/sensor data of a tool holder according to the invention with a biaxial acceleration sensor with two radial measurement axes.

DETAILED DESCRIPTION OF THE INVENTION

[0080] Referring now to the figures of the drawing in detail, the first part of the following description will be directed to a tool holder 1 with a sensor arrangement as illustrated in FIGS. 1 to 8.

[0081] FIG. 1 shows a first embodiment of a tool holder 1 according to the invention, hereinafter referred to for short merely as tool holder 1 or first tool holder 1.

[0082] The tool holder 1 comprises a tool holder main body 35, which will hereinafter be referred to merely as main body 35. In order to achieve the greatest possible stiffness, the main body 35 is in this case of single-piece form. Said main body is produced in the conventional manner from metal.

[0083] In the context of the present invention, a single-piece configuration is also present if a component is generated in an additive process, for example from metal powder, or is assembled from multiple components in non-detachable fashion, for example by welding or brazing.

[0084] The tool holder 1, which extends (axially 31) along a tool holder axis of rotation D, hereinafter referred to merely as axis of rotation D, has a tool section 3 at its tool-side longitudinal end 2 (also referred to as a first axial end 2) and has a coupling section 6 at its opposite, coupling-side longitudinal end 5 (also referred to as a second axial end 5).

[0085] The tool section 3 comprises a tool-receiving formation 4 in the form of a tool-receiving recess 4. A shaft of a tool (not illustrated in FIG. 1) can be axially 31 inserted into said tool-receiving recess 4 from the tool-side longitudinal end 2.

[0086] The tool section 3 of the tool holder 1 is designed, in a manner known per se, as a shrink chuck, in which a shaft of a tool (not illustrated in FIG. 1) can be clamped utilizing the thermal expansion and shrinkage of the material of the main body.

[0087] In the example of a tool holder 1 shown in FIG. 1, the coupling section 6 comprises a coupling formation 7 in the form of a hollow shaft cone, referred to for short as HSC.

[0088] As can be seen from further exemplary embodiments which are not shown, the tool section 3 may also be designed in accordance with some other clamping principle, such as that of a hydraulic expansion chuck. Independently of this, it is likewise possible for the coupling section 6 to be configured with some other shaft design.

[0089] Axially 31 between the tool section 3 and the coupling section 6, there may be provided a handling formation 36 for the handling of the tool holder 1, for example by a gripper apparatus. As illustrated in FIG. 1, the handling formation 36 may comprise a gripper channel 37 which encircles the axis of rotation D in the circumferential direction 21.

[0090] In the example shown in FIG. 1, a central recess 38 extends axially 31 all the way through the main body 35, of which central recess 38 the tool-receiving recess 4 forms an axial section which can serve inter alia for the supply of coolant through the tool holder 1 to the processing location, at which processing location the tool (not illustrated) that is clamped in the tool holder 1 is in processing engagement with a workpiece to be processed, for example milling processing in the case of a milling tool.

[0091] For the monitoring of the operation of the tool holder 1 during the workpiece processing, the tool holder 1 is equipped with a measuring apparatus 8.

[0092] Said measuring apparatus 8 also makes it possible to identify, for example, abnormal states, such as tool breakages/wear, vibrations or other instabilities, for example chatter, in the tool holder 1. For this purpose, signals/data of the measuring apparatus are analyzed and evaluated/processed.

[0093] For this purpose, the measuring apparatus 8 provides various components which are arranged on the tool holder 1 and which are connected to one another (via cables), such as an acceleration sensor 9, an SMD antenna 11, a microcontroller (μC) 10 and a voltage/energy supply or battery 16 (cf. in particular FIGS. 2 to 8), which components are normally located, in accordance with a modular construction, as described below, on separate boards 12, 13, 14, 15 which are connected to one another via connection lines/cables 23 (not illustrated), 24, 25, such as a main board 14 with microcontroller (μC) 10, a (sensor) board 13 with acceleration sensor 9, and an (antenna) board 15 with SMD antenna 11.

[0094] Biaxial Acceleration Sensor 9

[0095] A major constituent part of the measuring apparatus 8 is, as illustrated in particular in FIGS. 6 to 8, a—in this case—biaxial acceleration sensor 9, the two measurement axes x and y of which are arranged orthogonally with respect to one another.

[0096] Implemented in modular fashion, and in order to be independent of other components of the measuring apparatus 8, this acceleration sensor 9 is located separately on a separate (sensor) board 13 (cf. FIGS. 7 and 8).

[0097] In order to keep centrifugal force influences on the acceleration sensor 9 resulting from the rotation of the tool holder 1 as low as possible, the acceleration sensor 9 is, as shown in particular in FIG. 6, located at the central point/on the axis of rotation D in the tool holder 1, wherein the measurement axes x and y (which are orthogonal with respect to one another) are oriented normally with respect to the axis of rotation D (and thus measure radial (32) accelerations in the axial directions x and y) (cf. FIG. 6).

[0098] As an alternative to this biaxial acceleration sensor 9, use may also be made of a triaxial acceleration sensor, the—then—three measurement axes x, y, z of which—in this case then—span an orthogonal coordinate system, and the third measurement axis z of which is then oriented axially 31 with respect to the tool holder axis of rotation (D) (not shown).

[0099] The (sensor) board 13 is, as is also shown in FIG. 6, adhesively bonded in a housing 39 which can be screwed—instead of the coolant pipe—into the tool holder 1. The acceleration sensor 9 is adhesively bonded directly to the housing 39 by means of instant adhesive.

[0100] The connection between the (sensor) board 13 and the main board 14 is, as can be seen in particular from FIG. 8 and FIG. 7, implemented in wired form (connection line 23 for the acceleration sensor 9 with plug connector 40 for a plug contact 26 for the connection line 23). A corresponding plug contact 26 is provided for this, that is to say for the plug connector 40, on the main board 14. It is also possible for wireless connections to be provided between the components instead of the wired connections.

[0101] Main Board 14 with Microcontroller (μC) 10

[0102] For the integration of the main board 14, which bears the microcontroller (μC) 10, into the tool holder 1, a circular or ring-shaped groove 33 which is concentric with respect to the axis of rotation D is formed into the tool holder 1, as shown in FIG. 3, which groove 33 runs around the central recess 38 in the tool holder 1 or the region of the coolant pipe (not illustrated here owing to the acceleration sensor).

[0103] The ring-shaped groove 33 is closed, as indicated in FIG. 2, by a cover 34 which can be screwed on, which is advantageous because this area is part of the HSC interface for the ejection of the tool holder 1 from the spindle.

[0104] Analogously to the (sensor) board 13 in the sensor housing 39, the main board 14 is potted (19) using a silicone protective coating after all components have been installed in the ring-shaped groove 33.

[0105] As illustrated by FIGS. 3 to 5, the main board 14 is designed as a flexible “strip”, because this yields major advantages in particular for the installation process. A flexible board can be adjusted into the shape of the circular groove 33 without great effort (here, cf. also FIG. 3 and FIG. 4) and is easier to handle/install than a rigid variant during the connection of the various connecting lines/cables 23, 24 (not illustrated) 25.

[0106] FIG. 5 shows the plan view of the populated main board 14 (without connected lines/cables 23, 24, 25 (cf. FIG. 8)). FIG. 5 shows the top side of the main board 14 on which all components are fitted; only the conductor tracks are present on the rear side of the main board 14.

[0107] All connection lines/cables 23, 24 (not illustrated), 25, such as that (23) for the acceleration sensor 9, that (25) for the energy supply 16 and that (24 (not illustrated)) for the antenna 11, are implemented by means of plug contacts 26, 27, 28, which is advantageous for easy and flexible installation.

[0108] Situated at the left-hand edge of the main board 14, as shown in FIG. 5, is the connection plug contact 26 for the connection line 23 or the plug connector 40 of the acceleration sensor 9. (Free) contacts 29 situated underneath may be used for further sensor signals if appropriate.

[0109] Located slightly to the left of the center of the main board 14 as it is shown in FIG. 5 is the microcontroller (μC) 10 with various components, which microcontroller reads out the signals/data from the acceleration sensor 9.

[0110] Signals/data are read out via SPI from the acceleration sensor 9, which—in this case—provides values for the two measurement axes, specifically x and y.

[0111] If more than one value is required at a point in time, then it is necessary for all values to be transmitted in one read operation. After a completed read operation, the values from the acceleration sensor 9 are discarded, and the chronologically subsequent values are loaded for the next read operation.

[0112] The acceleration sensor 9 transmits the data bytewise, wherein the individual values are each composed of two bytes. Additionally, the acceleration sensor 9 firstly transmits the “rear part” of the overall value, followed by the “front part”, which must be put together by the software of the microcontroller (μC) 10. The data are aggregated by the microcontroller (μC) 10 and prepared for transmission.

[0113] To the right of the center of the main board 14 as it is shown in FIG. 5, there are two facilities, that is to say plug contacts, for the connection of antennae, of which, in the case of the first tool holder 1, one (in this case the upper plug contact 27) is used for the SMD antenna 11, which transmits (by Bluetooth transmission) signals/data to outside the tool holder 1, for example to a CMS.

[0114] Further to the right in the case of the main board 14 as it is shown in FIG. 5, it is possible to see a multiplicity of programming contacts 30, and at the right-hand edge of the main board 14, it is possible to see the connections or the plug contact 28 for the voltage/energy supply 16.

[0115] In order to protect the components of the main board 14, the front and rear sides of the main board 14 may if appropriate have a protective foil 42 adhesively bonded thereon, as illustrated in FIG. 4.

[0116] SMD Antenna 11

[0117] The SMD antenna 11, which is located on the separate antenna board 15 (cf. FIG. 2), is attached to the tool holder 1, as shown in FIGS. 1 and 2, via a circular pocket 17 on the gripper collar 43, which circular pocket is connected via an oblique connecting/connection bore 22 (for the connection line 24 (not illustrated)), which is eccentric in order to prevent kinks in the connection line 24 (not illustrated), to the circular groove 33 that receives the main board 14.

[0118] If appropriate, a second, oppositely situated and identical circular pocket (17) may be formed in the gripper collar (43) in order firstly to improve the quality of balancing of the tool holder 1 and secondly to make it possible to realize other antenna concepts with two antennae (11) (and possibly improved transmission power as a result) (cf. in this case FIG. 9 or tool holder 1 according to the second embodiment with two wire antennae 11). For this purpose, the second antenna connection (in this case further plug contact 27) is already provided on the main board 14 (see above).

[0119] For the fastening of the antenna board 15 in the circular pocket 17, said antenna board is potted (19) by means of a silicone (or alternatively covered), or the same silicone protective coating 19 as for the main board 14 may be used.

[0120] Energy Supply/Battery 16

[0121] The energy/voltage supply 16 or the battery 16 is attached in a similar manner to the SMD antenna 11, as shown in FIGS. 1 and 2, via a further circular pocket 17 (battery compartment 45) on the gripper collar 43, which further circular pocket is—likewise—connected via an oblique connecting bore 22 (for the connection line 25), which is eccentric in order to prevent kinks in the connection line 25, to the circular groove 33 that receives the main board 14.

[0122] The battery 16 is fastened in the battery compartment 45 by means of a cover 20 that can be screwed on (cf. FIG. 1) which—capable of being screwed onto the battery compartment 45—closes the latter and simultaneously also produces contact with the battery 16. Said cover 20 also makes it possible for the battery 16 to be exchangeable from the outside.

[0123] If appropriate, it is also possible for a seal (not illustrated) to be provided at the battery compartment 45, which seal protects the battery compartment against an ingress of liquid (not shown).

[0124] The following part of the description is directed to the tool holder 1 with sensor arrangement as illustrated in FIG. 9.

[0125] FIG. 9 shows a further embodiment of a tool holder 1 according to the invention, referred to for short merely as second tool holder 1.

[0126] This further or second tool holder 1 differs from that according to the first embodiment, that is to say the first tool holder 1 (cf. FIGS. 1 to 8), merely in that it provides a different type of antenna 11.

[0127] Aside from this, this second tool holder 1 also provides the acceleration sensor 9, as in the first embodiment, and also all of the other components, which are however not mentioned in any more detail hereinbelow but have been described in conjunction with the first tool holder 1. More detailed statements in this regard can be found in the statements relating to the first tool holder 1.

[0128] By contrast to the first embodiment (here, an SMD antenna 11 has been installed in a circular pocket 17 on the circumference 21 of the first tool holder 1 (cf. FIG. 2)), this second tool holder 1 provides, as shown in FIG. 9, two wire antennae 11 which—in each case likewise arranged in recessed fashion in circular pockets 17—are arranged in uniformly distributed fashion on the circumference 21 of the second tool holder 1. Said wire antennae are also each connected via connection lines/cables to the main board or antenna connections/plug contacts 27 situated thereon.

[0129] Here, too, the circular pockets 17, which receive the two wire antennae 11, on the circumference 21 of the tool holder 1 may again be potted by means of a silicone (19) (or alternatively covered).

[0130] Although the invention has been illustrated and described in more detail using the preferred exemplary embodiments, the invention is not restricted by the disclosed examples and other variations can be derived therefrom without departing from the scope of protection of the invention.

[0131] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0132] 1 Tool holder [0133] 2 (First, tool-side) axial longitudinal end [0134] 3 Tool section [0135] 4 Tool-receiving formation, tool-receiving recess [0136] 5 (Second, coupling-side) axial longitudinal end [0137] 6 Coupling section [0138] 7 Coupling formation [0139] 8 Measuring apparatus [0140] 9 (Acceleration) sensor [0141] 10 Microcontroller (μC) [0142] 11 Transmission device, antenna, SMD antenna, wire antenna [0143] 12 Circuit board, board [0144] 13 (Sensor) board [0145] 14 Main board [0146] 15 (Antenna) board [0147] 16 Energy supply, voltage supply, battery [0148] 17 Depression, circular pocket [0149] 18 Outer surface [0150] 19 Potting compound, silicone compound [0151] 20 Lid, cover (for battery compartment) [0152] 21 Circumferential direction (of the tool holder (1)), also circumference [0153] 22 Connection bore, connecting bore [0154] 23 Connection line (for acceleration sensor) [0155] 24 Connection line (for transmission device) [0156] 25 Connection line (for energy supply) [0157] 26 Plug contact(s) for the connection line (for the acceleration sensor) [0158] 27 Plug contact(s) for the connection line (for the transmission device) [0159] 28 Plug contact(s) for the connection line (for the energy supply) [0160] 29 Free plug contacts [0161] 30 Programming contacts [0162] 31 Axial direction [0163] 32 Radial direction [0164] 33 Annular/ring-shaped groove [0165] 34 Cover (for ring-shaped groove) [0166] 35 (Tool holder) main body [0167] 36 Handling formation [0168] 37 Gripper channel [0169] 38 Central recess [0170] 39 Housing (for the (sensor) board 13) [0171] 40 Plug connector (for the plug contact for the connection line (for the acceleration sensor)) [0172] 41 Plug connector (for the plug contact for the connection line (for the energy supply)) [0173] 42 Protective film [0174] 43 Gripper collar [0175] 45 Battery compartment [0176] D Tool holder axis of rotation, axis of rotation [0177] x Measurement axis [0178] y Measurement axis [0179] z Measurement axis [0180] ZEF Central meshing frequency