SHRINK-FIT DEVICE AND METHOD FOR INDUCTIVELY HEATING SHRINK-FIT CHUCKS

Abstract

This disclosure relates to a shrink-fit device for inductively heating shrink-fit chucks for shank tools, having an accommodating region for accommodating a shrink-fit chuck, an induction coil arrangement which surrounds the accommodating region concentrically with respect to a coil axis, and a measuring unit for controlling the temperature of the shrink-fit chuck. For controlling heating, a measuring channel, which opens into the accommodating region, passes through the induction coil arrangement. The measuring unit has a temperature sensor which engages in the measuring channel for detecting a casing temperature of the shrink-fit chuck.

Claims

1. A shrink-fit device for inductively heating shrink-fit chucks for shank tools, the device comprising: an accommodating region configured to accommodate a shrink-fit chuck; an induction coil arrangement surrounding the accommodating region concentrically with respect to a coil axis; a measuring channel passing through the induction coil arrangement and opening into the accommodating region; and a measuring unit configured to control the temperature of the shrink-fit chuck, the measuring unit including a temperature sensor configured for detecting via the measuring channel a casing temperature of the shrink-fit chuck.

2. The shrink-fit device according to claim 1, wherein the measuring channel extends through the induction coil arrangement transversely to the coil axis.

3. The shrink-fit device according to claim 2, wherein the measuring channel is arranged radially with respect to the coil axis.

4. The shrink-fit device according to claim 1, wherein the measuring channel is arranged in an axial central region of the induction coil arrangement.

5. The shrink-fit device according to claim 4, wherein the measuring channel is arranged centrally between the ends of the induction coil arrangement.

6. The shrink-fit device according to claim 1, wherein the induction coil arrangement has a coil winding which is wound and the measuring channel is open.

7. The shrink-fit device according to claim 1, wherein the measuring channel comprises an opening through a housing of the induction coil arrangement.

8. The shrink-fit device according to claim 1, wherein the temperature sensor is arranged at least partly in the measuring channel.

9. The shrink-fit device according to claim 1, wherein the temperature sensor is configured for contactless detection of the casing temperature.

10. The shrink-fit device according to claim 1, wherein the measuring unit comprises a pyrometer and the temperature sensor is a radiation detector aligned with the accommodating region, the radiation detector configured to detect thermal radiation emitted by a shrink-fit chuck located in the accommodating region.

11. The shrink-fit device according to claim 1, further comprising a thermal radiation-permeable protective window placed in the measuring channel to protect the temperature sensor from contamination.

12. The shrink-fit device according to claim 1, further comprising a controller for controlling the heating of the shrink-fit chuck during heating, the controller configured to influence the power supply to the induction coil arrangement as a function of the casing temperature.

13. A method for inductively heating a shrink-fit chuck in a shrink-fit device, the method comprising: placing a shrink-fit chuck into an accommodating region of the shrink-fit device; heating an induction coil arrangement that concentrically surrounds the accommodating region and thereby inductively heating the shrink-fit chuck, whereby the shrink-fit chuck thermally expands; and controlling the temperature of the shrink-fit chuck using a measuring unit in which a casing temperature of the shrink-fit chuck is detected via a measuring channel passing through the induction coil arrangement.

14. The method of claim 13, wherein power provided to the induction coil arrangement is varied depending on casing temperature.

15. The method according to claim 13, wherein the casing temperature is brought to a predetermined target value by controlling a power supply to the induction coil arrangement.

16. The method according to claim 15, further comprising maintaining the temperature at the predetermined target value.

17. The method according to claim 13, wherein a power supply to the induction coil arrangement is maintained or reduced or switched off when a predetermined target value of the casing temperature is reached.

18. The method according to claim 13, wherein the shrink-fit chuck is positioned relative to the temperature sensor by a stop.

19. The method of claim 18, wherein the stop comprises a pole disk of the induction coil arrangement.

20. The method according to claim 13, wherein the measured casing temperature is displayed for an operator via a display.

21. The method according to any of claim 13, wherein the casing temperature is displayed with light-emitting diodes.

22. The method according to claim 21, wherein the light emitting diodes ac colored in the manner of a traffic light.

23. The method according to claim 13, wherein the casing temperature is measured during the inductive heating and/or in a time interval thereafter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0024] FIG. 1 is an axial section of a shrink-fit device with integrated heating control for a shrink-fit chuck to be heated;

[0025] FIG. 2 is a perspective view of an induction coil arrangement of the shrink-fit device with a transverse opening as a measuring channel; and

[0026] FIG. 3 is a radial section in the region of the measuring channel through the induction coil arrangement according to FIG. 2.

DESCRIPTION

[0027] The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

[0028] The shrink-fit device 10 shown in FIG. 1 is used to shrink a shaft tool 12 into or out of a shrink-fit chuck 14. For this purpose, it comprises an induction coil arrangement 16 for inductively heating the shrink-fit chuck 14 and a control unit (also referred to as a “controller”) 18, shown only symbolically, for controlling the heating of the shrink-fit chuck 14.

[0029] The shrink-fit chuck 14 comprises, as a sleeve part, a cylindrically hollow clamping region 20, which is accessible via an end opening 22 at the front end of the shrink-fit chuck 14 for inserting the tool shaft 24. The clamping region 20 has a slightly smaller nominal diameter than the tool shank 24, such that it can be clamped in a manner known per se by (inductive) heating of the shrink-fit chuck 14. In the shrunk-on state, the tool shank 24 is held in a press fit in a frictional manner in order to transmit a torque to the front working portion of the rotary tool 12. For shrinking out, only the shrink-fit chuck 14 is heated on one side until the thermal expansion releases the tool shank 24 for removal.

[0030] The induction coil arrangement 16 encloses an accommodating region 26 for the shrink-fit chuck 14 in a concentric arrangement with respect to the coil axis 28 or tool axis 30. The shrink-fit chuck 14 is brought into the heating position shown by an axial movement relative to the induction coil arrangement 16. The shrink-fit chuck 14 can be axially positioned by means of a pole disk 32 acting as a stop.

[0031] In order to generate an electromagnetic alternating field, the induction coil arrangement 16 contains a coil winding 34, shown symbolically hatched, in a coil housing 36. The coil winding 34 is enclosed in a casting compound 38, the inner cavity being adapted to the conical shape of the casing 40 of the shrink-fit chuck 14.

[0032] In order to be able to detect the casing temperature of the shrink-fit chuck 14 during heating, a measuring channel 42, which opens into the accommodating region 26, passes through the induction coil arrangement 16 radially with respect to the coil axis 28. In this case, the measuring channel 42 is expediently arranged in an axial central region of the induction coil arrangement 16, preferably centrally between the ends thereof, the coil winding 34 being wound around the measuring channel 42 while keeping said measuring channel free. The inner portion of the measuring channel 42 on the coil side is aligned with an opening 44 in the outer wall 38 of the coil housing 36.

[0033] The control unit 18 is coupled on the input side to a measuring unit 46 for detecting a casing temperature of the shrink-fit chuck 14. For this purpose, the measuring unit 46 is designed as a pyrometer for contactless temperature detection.

[0034] The measuring unit 46, which operates pyrometrically in a manner known per se, has a radiation detector as a temperature sensor 48 which is inserted into the opening 44 and which detects heat radiation emitted by the shrink-fit chuck 14 through the measuring channel 42 in the coil winding 34. As a result, the temperature can be controlled during the heating of the shrink-fit chuck 14 and optionally the power supply to the induction coil arrangement 16 can be influenced depending on the casing temperature. In order to protect the temperature sensor 48 from contamination, a protective window 49 which is permeable to thermal radiation is inserted into the measuring channel 42.

[0035] As can be seen from FIGS. 2 and 3, the cast-in coil winding 34 has an extension 50 on which the power connections 52 are accessible for the power supply. It is possible to control the temperature of the coil winding 34 on the basis of a PTC sensor (not shown) via additional measuring connections 54.

[0036] During operation of the shrink-fit device 10, the control unit (controller) 18 connected on the output side to the power connections 52 of the induction coil arrangement 16 can bring the casing temperature to a predetermined target value by controlling the power supply and optionally keep it at this target value. The control unit 18 can act as a closed-loop control device in a closed control loop. In a simplified mode of operation, it is also conceivable for the power supply to the induction coil arrangement 16 to be reduced or switched off when a predetermined target value of the casing temperature is reached.

[0037] The measured casing temperature can be displayed for an operator via a display 54 control unit 18. This can be done particularly clearly by visualizing the casing temperature by means of light-emitting diodes 56 colored in the manner of a traffic light.

[0038] While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.