Tool for roughening a metallic surface

Abstract

A roughening tool for roughening a metallic surface of an inner wall of a pre-drilled workpiece bore is disclosed. The roughening tool has a profiled contour provided between the tool clamping shaft and the tool tip. With this contour, a roughened structure can be produced through rotation of the tool by processing the metallic surface in a material removing or non-material removing manner The roughening tool includes at least one profiled web which extends along the tool axis, protrudes from a main tool part, and on whose outer web back the profiled contour is provided.

Claims

1. A roughening tool for roughening a metallic surface of an inner walling of a pre-drilled workpiece bore, said roughening tool comprising: a profiling web protruding from a base body of the roughening tool and extending along an axis of the roughening tool, said profiling web having an outer web back provided with a profiling contour extending between a tool tip of the roughening tool and a mounting shaft of the roughening tool, said profiling web ending at the tool tip of the roughing tool with a groove blade, which is oriented transverse to the axis of the roughening tool, said groove blade being adapted to enable insertion of the roughening tool into pre-drilled workpiece bore with an axial lift movement, and during said lift movement to form a profiling groove in the inner walling of the pre-drilled workpiece bore, said profiling groove extending along the longitudinal axis of the core bore, said profiling web being adapted to engage in the profiling groove and through rotation of the roughening tool to generate the roughened structure by material-removing or non-material removing processing of the metallic surface of the inner walling of the pre-drilled workpiece bore, when received in the profiling groove and upon rotation of the roughening tool.

2. The roughening tool of claim 1, wherein a first diameter of the roughening tool at the groove blade is greater than a second diameter of the roughening tool at the profiling contour.

3. The roughening tool of claim 1, wherein a first tool diameter of the roughening tool at the groove blade is equal to a second tool diameter of the roughening tool at the profiling contour.

4. The roughening tool of claim 1, wherein the groove blade has a groove-base cutting edge, which converges at a first blade corner with a profiling cutting edge which extends along the tool axis.

5. The roughening tool of claim 1, wherein the groove blade has a first groove-wall cutting edge and a second groove-wall cutting edge, said first and second groove-wall cutting edge being angled with respect to the groove base cutting edge so that the profile groove formed in the workpiece has a dovetail shape in which side walls of the profile groove form undercuts.

6. The roughening tool of claim 1, wherein the profiling web at least in a region of the tool tip has at least one of a chip surface, which faces a groove shaped chip space, and a free surface provided on the web back.

7. The roughening tool of claim 6, wherein the at least one chip surface and the free surface converge at the profiling cutting edge.

8. The roughening tool of claim 6, wherein a groove-chip surface is formed on the end side of the tool tip, and wherein the free surface and the groove-chip surface converge at a groove base cutting edge of the groove blade.

9. The roughening tool of claim 8, wherein the groove chip surface formed at the tool tip is delimited by the groove base cutting edge and by a first and a second groove-wall cutting edge of the groove blade, which each transition at a first and a second blade corner of the groove blade into the groove base cutting edge.

10. The roughening tool of claim 1, wherein the profiling web extends with an angle of twist spirally about the tool axis, and wherein in particular the profiling groove is formable so as to extend spirally in the inner walling of the core bore with the axial lift movement and a rotational movement of the roughening tool which is adjusted to the angle of twist.

11. The roughening tool of claim 6, wherein the groove chip surface of the groove blade is extended radially inwards with a chip guiding surface formed on the end side of the tool, said chip guiding surface being adapted to push chippings generated during cutting of the profile groove into the chip space which extends along the tool axis.

12. The roughening tool of claim 1, further comprising at least one drilling-out blade protruding radially from the tool base body and extending along the tool axis.

13. The roughening tool of claim 12, wherein the drilling-out blade has at least one drilling-out web, said at least one drilling-out web having a chip surface which faces a groove shaped chip space of the roughening tool, and an outer free surface, said chip surface and said outer free surface converging at a drilling-out cutting edge of the drilling out blade, said drilling-out cutting edge extending along the tool axis, and being adapted to drill out the core bore to a final diameter through rotation of the roughening tool.

14. The roughening tool of claim 13, wherein the drilling-out web terminates at the tool tip with another groove blade, said another groove blade being adapted to generate a drilling-out groove in the inner walling of the core bore during the axial lift movement prior to drilling the core bore to the final diameter, said drilling-out blade during the axial lift movement engaging in the drilling-out groove and upon rotation of the roughening tool drilling out the core bore to the final diameter.

15. The roughening tool of claim 14, wherein the profiling web and the drilling-out web are configured with a same slope.

16. The roughening tool of claim 14, wherein a diameter of a back of the drilling-out web is greater than a diameter of the core bore and smaller than a diameter of the profiling contour.

17. A method for roughening a metallic surface of an inner walling of a pre-drilled core-bore of a workpiece, said method comprising: providing a roughening tool which comprises a profiling web protruding from a base body of the roughening tool and extending along an axis of the roughening tool, said profiling web having an outer web back provided with a profiling contour extending between a tool tip of the roughening tool and a mounting shaft of the roughening tool, said profiling web ending at the tool tip of the roughing tool with a groove blade, which is oriented transverse to the axis of the roughening tool; in a pre-processing step inserting the roughening tool into the pre-drilled core bore of the workpiece in an axial lift movement, and during the axial lift movement forming with the groove blade a profiling groove in the inner walling of the core bore, said profiling groove extending along an axis of the core-bore; and in a final processing step, with the profiling web of the roughening tool being arranged in the profiling groove, rotating the roughening tool, whereby the profiling web processes the metal surface in a material removing or non-material removing manner thereby generating a roughened structure.

18. The method of claim 17, further comprising in the pre-processing step forming with a further groove blade provided on a drilling-out web of the roughening tool a drilling-out groove in the inner walling of the core-bore, and in the final processing step with a drilling-out blade of the drilling-out web drilling out the core bore to a final diameter through rotation of the roughening tool.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following the invention and its advantageous refinements and embodiments and its advantages are explained by way of drawings.

(2) It is shown in:

(3) FIG. 1 an enlarged perspective view of the region on the tool tip of a roughening tool according to the first exemplary embodiment;

(4) FIG. 2 a top view along the tool axis onto the tool tip of the roughening tool;

(5) FIG. 3 a view which shows the pre-processing step, in which the tool is inserted into the pre bore while forming the profiling groove;

(6) FIG. 4 a partial view of an unfolded core-bore inner walling after the performed final processing step;

(7) FIG. 5 a strongly enlarged schematic partial view of the roughening structure worked into the metallic surface of the inner walling of the core bore;

(8) FIG. 6 a view according to FIG. 2 of a roughening tool according to the second exemplary embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(9) FIG. 1 shows a roughening tool for roughening an inner walling 1 of a core bore 3 of a workpiece 5. The roughening tool has a not shown mounting shaft for mounting into a not shown tool chuck, and a tool body 9 adjoining the mounting shaft (FIG. 2). Extending between the flattened tool tip 11 and the mounting shaft are for example two profiling webs 13, which are diametrically opposed to each other with respect to a tool axis L and are configured point symmetric to each other. The two profiling webs 13 extend spirally with an angle of twist about the tool axis L. Each profiling web 13 has a chip surface 17, which faces a respective groove-shaped chip space 19 and an free surface 21 at the outer circumference. The chip surface 17 and the free surface 21 of the profiling web 15 at the outer circumference converge in the region of the tool tip 11 at a profiling cutting edge 23, which extends along the tool axis L. By means of the profiling cutting edge 23 a circumferential annular groove 24, shown in FIG. 4, is generated in the inner walling 1 of the pre-drilled core bore 3 of the workpiece through tool rotation R.

(10) At the tool tip 11 each of the profiling webs 13 ends with a groove blade 25, which is oriented transversely relative to the tool axis L. By means of the groove blade 25 the roughening tool can be inserted, in a described pre-processing step I described below, into the core bore 3 in a threading mode, i.e., with a translational lift movement h (FIG. 3) and a rotation that is adjusted to the tool angle of twist. This results in the diametrically opposed profile grooves 27 shown in FIG. 3, which extend spirally along the core-bore axis.

(11) According to FIG. 2, the groove blade 25 has a groove base cutting edge 29. The groove base cutting edge converges at a first blade corner 31 with the profiling cutting edge 23. In addition also the outer circumferential free surface 21 of the profiling web 13 and an end-side groove chip surface 33 converge at the groove base cutting edge 29. According to FIG. 1 the groove chip surface 33 is delimited by the groove base cutting edge 29 and by a first groove wall cutting edge 35 and a second groove wall cutting edge 37. The first groove wall cutting edge 35 transitions at the already mentioned blade corner 31 into the groove base cutting edge 29. The second groove wall cutting edge 37 transitions at a second blade corner 39 into the groove base cutting edge 29.

(12) Divergent from the situation depicted in the Figures the first groove wall cutting edge 35 and the second groove wall cutting edge 37 can be angled relative to the groove base cutting edge 29 so that each of the profile grooves 27 has a dovetail shape in which the groove side walls of the respective profile groove 27 form undercuts.

(13) As further shown in FIG. 1 a profiling contour 20 adjoins the free surface 21 of the profiling web 13 in a longitudinal extent away from the tool tip 11, with which profiling contour 20 a roughened structure 22 described in FIG. 6 is generated on the inner walling 1 of the core bore. In the further course in the direction of the mounting shaft the profiling cutting edge 23 transitions into abutment edges 24 (FIG. 1) of the profiling contour 20. The abutment edges 24 of the profiling contour 20 protrude radially outward from the tool base body 9 with a profile height h.sub.p. The profile height h.sub.p is hereby smaller than the web height h.sub.N at the groove blade 25. On the other hand the web width in the region of the groove blade 25 and in the region of the profiling contour 20 is identical. As an alternative the web width in the region of the profiling contour 20 can also be smaller than the web width in the region of the groove blade 25.

(14) According to FIG. 1 the groove base cutting edge 29 is slanted at a work angle with respect to a plane that is perpendicular to the tool axis L. The work angle is approximately 45 and is selected so that when viewed in the direction of rotation R the leading, first blade corner 31 is spaced apart from the tool tip 11 by a longitudinal offset a.sub.1. On the other hand in FIG. 1 the second trailing blade corner 39 is oriented flush (i.e. without longitudinal offset) with the tool tip 11.

(15) The above mentioned groove chip surface 33 of the groove blade 25 is extended radially inwards with a chip guiding surface 41. By means of the chip guiding surface 41 the chippings generated during the groove cutting are pushed into the chip space, which extends along the tool axis L. As can be seen from the Figures the chip guiding surface 41 is formed by a corner recess 43 at the transition between the tool tip and the chip space 19. The removal of the chippings, the lubrication and/or cooling is supported for example by using a coolant/lubricant which is conducted with high pressure out of the coolant outlets (not shown) in the tool tip and into the chip spaces 19 in order to transport the chippings out of the core bore 3.

(16) FIG. 3 illustrates the method for roughening the core-bore inner walling 1. Accordingly in a first pre-processing step I the tool is first inserted into the pre-drilled workpiece core probe 3 in a threading mode, i.e., with a low rotational speed and an axial lift movement h adjusted to this rotational speed. As a result the opposing spiral-shaped profiling grooves 27 are formed. Due to the geometry of the profiling web the groove depth t of the two grooves 27 is hereby configured so that its groove base is positioned radially outside the profiling contour 20.

(17) In this way the profiling contour 20 is inserted in the preprocessing step I into the profiling grooves 27 without mechanical stress. After the formation of the two profiling grooves 27 the boring tool remains in its inserted state in which the two profiling webs 13 are in engagement with the two profiling grooves 27.

(18) In the following final processing step II the roughening tool is then impinged with at least half a rotation (i.e. at least with a rotation angle of 180), wherein depending on the configuration of the profiling contour 20, a material-removing or non-material-removing processing of the metallic surface of the core-bore inner walling 1 occurs. Subsequently the roughening tool is operated in the inverse threading mode for withdrawal from the core bore 1, i.e., in opposite direction of rotation.

(19) As shown in FIG. 2 the envelope curve diameter d.sub.N of the tool in the region of the groove blade 25 is greater that the envelope curve diameter d.sub.P in the region of the profiling contour 20. Correspondingly the roughened structure 22 shown in FIG. 4 results on the inner walling 1 of the core bore 3 after the roughening process, according to which the two profile grooves 27 extend obliquely with a groove depth along the core bore axis. On the other hand the roughened structure 22 extends perpendicular to the core bore axis. In the lower region of the unfolded view the circumferential annular groove 24 is formed, which results in the final processing step II due to the rotation of the groove blade 25. According to FIG. 5, the roughened structure 22 has for example straight extending receptacles 28 which in cross section have a dovetail shape. For forming such a dovetail shape the abutment edges 24 of the profiling contour 20 can have the geometries indicated with hatched lines in FIG. 5.

(20) FIG. 6 shows a roughening tool according to a second exemplary embodiment, which also has two profile webs 13 that are diametrically opposed to each other with respect to the tool axis L. In addition circumferentially offset drilling-out blades 34 are provided which radially protrude from the tool base body 11. The two drilling-out blades 34 are arranged together with the profiling webs 13 with same angular distances circumferentially distributed about the outer circumference of the tool base body 9. Each of the drilling-out blades 34 has a chip surface 38, which faces a groove-shaped chip space 36 and an outer free surface 39, which is arranged on the back of the web. The chip surface 38 and the free surface 39 converge at a drilling-out cutting edge 41, which extends along the tool axis L. In addition the profiling webs 13 and the drilling-out webs 35 are each configured with the same slope in the tool.

(21) By means of the drilling-out cutting edge the core bore 3 can be drilled out to a final diameter d.sub.E (FIGS. 3 and 6) by rotation of the drilling-out tool (i.e., in the final processing step II).

(22) As shown in FIG. 3, in the pre-processing step I not only the profile grooves 27 but also the drilling-out grooves 43 (one is indicated with dashed lines in FIG. 3) are generated in the core-bore inner walling 1. In the following final processing step II additionally a drilling-out process is performed in which the drilling-out blade 34 drills out the core bore to the final diameter d.sub.E.