TOOL HOLDER WITH FLUID SUPPLY

Abstract

A tool holder is disclosed for holding a tool shaft of a tool, the tool holder having a receiving bore for receiving the tool shaft in a predetermined axial position, having a seal at an inner end of the receiving bore, and further comprising a coolant supply from a machine-side into a bore of the tool shaft, wherein the seal has an at least partially elastically deformable sealing element.

Claims

1. A tool holder for receiving a tool at a tool shaft thereof, said tool holder comprising: a receiving bore for receiving said tool shaft within a predetermined axial position; a sealing provided at an inner end of said receiving bore; and a coolant feeding canal leading into a central bore of said tool shaft from a machine-side; wherein said sealing, being held at an end of said receiving bore in a predetermined mounting position, is configured as a plug comprising a central coolant passage; wherein said sealing, at its end facing said tool shaft, comprises an at least partially elastically deformable sealing element protruding to the outside; and wherein said sealing element further comprises at least one sealing lip protruding into an undercut at an end of said receiving bore.

2. A tool holder for receiving a tool at a tool shaft thereof, the tool holder comprising: a receiving bore for receiving the tool shaft within a predetermined axial position; a central bore arranged within the tool for feeding coolant toward said tool shaft; a sealing arranged at an inner end of said receiving bore, said sealing comprising an at least partially elastically deformable sealing element protruding into said receiving bore for sealing with an axial end of a tool shaft received within said central bore.

3. The tool holder of claim 2, wherein said sealing is configured as a plug comprising a central coolant passage being held at said end of said receiving bore in a predetermined mounting position.

4. The tool holder of claim 3, wherein said plug comprises a male thread held adjustably within a female thread of said tool holder.

5. The tool holder of claim 2, wherein said at least partially elastically deformable sealing element comprises an elastomeric plastic material.

6. The tool holder of claim 5, wherein said plug in total consists of an elastomeric plastic material.

7. The tool holder of claim 5, wherein said plug comprises a base body made of a metal configured as a screw having a male thread, said screw having an outside end holding an at least partially elastically deformable sealing element made of an elastic plastic material.

8. The tool holder of claim 5, wherein said at least partially elastically deformable sealing element comprises a metal.

9. The tool holder of claim 8, wherein said sealing element comprises a coating made of a plastic material.

10. The tool holder of claim 2, wherein said receiving bore at its inner end comprises an undercut, and wherein said sealing element comprises at least one sealing lip protruding into said undercut.

11. The tool holder of claim 10, wherein said sealing element comprises two sealing lips protruding into said undercut.

12. The tool holder of claim 11, wherein said sealing element comprises a first sealing lip for sealing with a shoulder arranged at the end of said receiving bore.

13. The tool holder of claim 12, wherein said sealing element comprises a second sealing lip for sealing with an end of said tool shaft.

14. The tool holder of claim 11, wherein said two sealing lips are connected with each other by means of a concave annular groove.

15. The tool holder of claim 3, wherein said plug at a first end facing outwardly comprises a first tool receptacle for receiving a screwdriver tool.

16. The tool holder of claim 15, wherein said plug at a second machine-side end comprises a second tool receptacle for receiving a screwdriver tool.

17. A tool holder for receiving a tool at a tool shaft thereof, said tool holder comprising: a tool holder body comprising a receiving bore for receiving said tool shaft within a predetermined axial position; a central bore arranged within said tool holder body for feeding coolant toward said tool shaft; a sealing arranged at an inner end of said receiving bore; a coolant lance being sealed against said tool holder body for feeding coolant into a central bore of said tool shaft; and a control bore arranged within said tool holder leading from said receiving bore to the outside for detecting a leakage.

18. The tool holder of claim 17, wherein said control bore yields within a region of an undercut that is configured for receiving an axial adjusting screw.

19. The tool holder of claim 17, further comprising a sensor being connected to said control bore.

20. The tool holder of claim 1 being configured for receiving a tool within a shrink-fit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Further features and advantages of the invention can be taken from the subsequent description of preferred embodiments with reference to the drawings. In the drawings show:

[0050] FIG. 1 a longitudinal section through a tool holder according to the invention including an inserted tool;

[0051] FIG. 2 an enlarged cross-sectional representation of the tool holder according to FIG. 1, shown in the region of the axial end of the tool holder shaft and the plug according to FIG. 1, wherefrom the construction of the sealing can be seen in more detail;

[0052] FIG. 3 a longitudinal section through the tool holder according to FIG. 1, however shown with a different sectional plane running through a control bore;

[0053] FIG. 4 a longitudinal section through the tool holder according to FIG. 3, wherein in addition an insertion tool for mounting the plug is shown;

[0054] FIG. 5 a partially sectioned side representation of an alternative configuration of the plug according to FIG. 4;

[0055] FIG. 6 a view of the plug according to FIG. 5, seen from the right side; and

[0056] FIG. 7 a view of the plug according to FIG. 5, seen from the left side.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0057] FIG. 1 shows a cross sectional representation of a tool holder according to the invention designated in total with numeral 10.

[0058] The tool holder 10 comprises a tool holder body 12, having a clamping cone on the tool side for receiving a tool 16 in thermal shrink-fit. On the machine side, the tool holder 10 in the generally known way comprises a securing section 13 comprising an annular flange including a peripheral groove allowing for an automatic handling by means of a tool changer or similar.

[0059] For receiving the tool 16 within the tool holder body 12, a receiving bore 14 is provided which is configured for receiving a tool shaft 18 by force-fit in generally known way by means of thermal shrinking.

[0060] Adjacent to the receiving bore 14, a plug 30 made of an elastomeric or plastic material is screwed with a male thread 30 into an assigned female thread 32 of the tool holder body 12. The plug 28 comprises a sealing element 36 the diameter of which is enlarged with respect to the remaining part of the plug 28 and which protrudes into the end of the receiving bore 14, as will be subsequently explained in more detail with respect to FIG. 2.

[0061] The plug 28 comprises a central coolant passage 29 to allow a passage of coolant fed from the machine side into a central bore 44 of the tool holder shaft 18 by means of minimum quantity lubrification.

[0062] The respective coolant is fed from the machine side by means of a coolant lance 22 which is screwed into the tool holder body 12 by means of a threaded connection 24 and which is sealed against the tool holder body 12 by means of suitable sealing elements configured as sealing rings 25, 26. Thus, a tight feeding of the coolant via the coolant lance 22 up to the coolant passage 29 of the plug 28 results.

[0063] Now according to the invention, the plug 28 is sealed with respect to the axial end of the tool shaft 18 as will be subsequently explained in more detail with reference to FIG. 2.

[0064] According to FIG. 2 a first sealing lip 38 and a second sealing lip 40 are formed at the sealing element 36 of the plug 28. The first sealing lip is configured for resting against a shoulder 39 of the receiving bore 14 forming the inner end of the receiving bore.

[0065] The second sealing lip 40 protrudes with respect to the first sealing lip 38 into the direction of the tool shaft 18 and has a somewhat larger diameter than the first sealing lip 38 so that a resting against the inner surface in the region of the undercut 34 results, whereby the diameter is somewhat enlarged at the inner end of the receiving bore 14. The two sealing lips 38, 40 are connected with each other by means of a concave annular groove 37.

[0066] The second sealing lip 40 is configured for direct resting against the slanted end 42 of the tool shaft 18, namely such that the second sealing lip 40 is pressed by the slanted surface 42 of the tool shaft 14 to the outside against the inner surface of the undercut 34, and thus the sealing effect is improved when the tool shaft 18 is pressed into the direction of the machine side.

[0067] Thus, a two-fold sealing effect results, namely on the one hand by a resting of the first sealing lip 38 against the shoulder 39 of the receiving bore 14, and on the other hand by a resting of the second sealing lip 40 against the inner surface of the undercut 34 with additional pressure bias by means of the slanted end 42 of the tool shaft 18.

[0068] In this way already at a low pressure bias, such as generated by the thermal shrinking of the tool shaft 16 into the tool holder 10, a reliable sealing is ensured at the end 42 of the tool shaft 18.

[0069] In FIG. 2, a radial control bore 46 is depicted that yields into the undercut 34. At the outer end of the control bore, in addition a sensor 48 is depicted by a dashed line.

[0070] When the sealing is in good order by means of the plug 28, no coolant can escape into the region of the undercut 34.

[0071] However, if due to any reason the sealing formed by the sealing element 36 should break down, then this would lead to the escape of coolant into the region of the undercut 34 so that coolant would emerge into the control bore 46, and the coolant escaped could be detected by means of the sensor 48.

[0072] In FIG. 4 in addition an insertion tool 50 is depicted by means of which the plug 28 with its male thread 30 can be brought into the assigned female thread 32 of the tool holder body 12 into a desired axial mounting position. For a correct centering of the plug 28 herein, a centering mandrel 53 at the front end of the insertion tool 50 is provided that engages with the central coolant passage 29 of the plug 28.

[0073] To ensure a simple adjustment or control, respectively, of the axial mounting position, at the insertion tool 50 a control feature 52 is provided. In the case shown here, the control feature 52 is formed by a shoulder of the insertion tool 50, the distance d of which to the front face 54 of the tool holder 10 yields a control measure. Thus, the plug can be easily adjusted into a desired axial mounting position which determines the later axial position of the tool shaft 18.

[0074] In FIGS. 5 to 7 a variant of the plug is shown which is depicted in total with 28a. Apart from that for corresponding parts corresponding reference numerals are utilized.

[0075] The plug 28a comprises a base body 41 made of steel having a male thread 30 for screwing into the female thread 32 of the tool holder body 12. At the tool-side end of the base body 41, the sealing element 36 is provided which is made of an elastomeric plastic material, e.g. fluororubber.

[0076] Apart from that, the plug 28a with respect to the shape and design is completely the same as the plug 28 described above.

[0077] By designing the plug 28a as a two-component-part, a later adjusting possibility also after shrink-fitting the tool 16 into the receiving bore 14 results, wherein the sealing with the tool end 42 is fully maintained via a wide adjusting region.

[0078] The representation according to FIG. 6 shows a screwdriver receptacle 56 for screwing the plug 28a into the female thread 32 of the tool holder body 12 from the tool side.

[0079] The view according to FIG. 7 on the opposite side of the plug 28a shows a screwdriver receptacle 58 configured as a hexagon socket which allows for a subsequent adjusting of the plug 28a even after a shrinking of the tool 16 within the receiving bore 14.