CHIP-REMOVING TOOL FOR DEBURRING BORES

Abstract

A chip-removing tool for deburring bores, which laterally open into a cylindrical recess for example, comprising a shaft; a cutting head with at least one cutting wedge on the circumference, said cutting wedge being paired with a flute and having a cutter, which extends in an axial direction at least in some sections, carries out a cutting process on the basis of a relative movement between the tool and a workpiece, and lies on a virtual cylindrical rotational surface with a diameter that corresponds to the nominal diameter of the chip-removing tool, and at least one cutting wedge- and flute-free surface region; at least one fluid channel closed on the cutting head side and extending through the shaft and into the cutting head; and at least one puncture channel which starts from the fluid channel and comprises an opening that lies in the cutting wedge- and flute-free surface region.

Claims

1. A chip-removing tool, for deburring bores, comprising: a shaft, a cutting head with at least one cutting wedge on the circumference, said cutting wedge being paired with a flute and having a cutter, which extends in an axial direction at least in some sections, carries out a cutting process on the basis of a relative movement between tool and workpiece, and lies on a virtual cylindrical rotational surface with a diameter that corresponds to a nominal diameter of the chip-removing tool, and at least one cutting wedge- and flute-free surface region, at least one fluid channel, which is closed on the cutting head side and which extends through the shaft and into the cutting head, and at least one puncture channel, which starts from the fluid channel and comprises an opening that lies in the cutting wedge- and flute-free surface region, the opening that lies in the cutting wedge- and flute-free surface region in a dynamic pressure active surface, which is radially recessed relative to the virtual rotational surface of the cutting head, and which is larger than a flow cross sectional surface of the at least one puncture channel at the opening.

2. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface is provided in such a way that the sum of the dynamic pressure forces created in the region of the dynamic pressure active surface between the chip-removing tool or the cutting head, respectively, and the inner wall of the recess, can deflect the shaft in the radial direction.

3. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface has a shape of an even surface.

4. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface has a shape of a trough-like depression.

5. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface is shaped concavely or convexly in a direction of the at least one puncture channel.

6. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface runs axially parallel to a longitudinal central axis of the tool.

7. The chip-removing tool according to claim 1, wherein the dynamic pressure active surface has a smaller axial length than the cutting head.

8. The chip-removing tool according to claim 7, wherein, viewed in a tool feed direction, the dynamic pressure active surface ends at a defied distance to a front and rear end of the cutting head.

9. The chip-removing tool according to claim 1, wherein the chip-removing tool has two straight-lined puncture channels, which starts at the at least one fluid channel.

10. The chip-removing tool according to claim 1, wherein the at least one fluid channel runs along a longitudinal central axis of the chip-removing tool.

11. The chip-removing tool according to claim 1, wherein the diameter of the cutting head is larger than a diameter of the shaft.

12. The chip-removing tool according to claim 1, wherein the cutting head has a plurality of cutting wedges comprising straight grooves.

13. The chip-removing tool according to claim 1, wherein a plurality of interior fluid channels are provided.

14. The chip-removing tool according to claim 1, wherein the cutting head has a gate at least on its side, which faces away from the shaft.

15. The chip-removing tool according to claim 1, wherein the tool is configured to function as a milling or drilling tool, or as a reamer.

16. The chip-removing tool according to claim 1, wherein the cutting head is divided in a circumferential direction into a cutting wedge partial region and a cutting wedge- and flute-free partial region, which forms the cutting wedge- and flute-free surface region.

17. The chip-removing tool according to claim 1, wherein the tool is a rotationally driven chip-removing tool.

18. The chip-removing tool according to claim 1, wherein the too is for deburring bores that laterally open into a cylindrical recess.

19. The chip-removing tool according to claim 12, wherein the cutting head has three cutting wedges comprising straight grooves.

Description

[0031] Different embodiments of a chip-removing tool according to the invention will be described below by means of the enclosed drawings.

[0032] FIG. 1 shows a perspective view of a chip-removing tool of a first embodiment;

[0033] FIG. 2 shows a first schematic side view of the chip-removing tool from FIG. 1;

[0034] FIG. 3 shows a second schematic side view of the chip-removing tool from FIG. 1;

[0035] FIG. 4 shows a cross sectional view of the cutting head of the chip-removing tool from FIG. 1;

[0036] FIG. 5 shows a detail A from FIG. 2 illustrated in an enlarged manner;

[0037] FIG. 6 shows a perspective view of a cutting head of the first embodiment of a chip-removing tool;

[0038] FIG. 7 shows a cross sectional view of the cutting head from FIG. 6;

[0039] FIG. 8 shows a perspective view of a cutting head of a second embodiment of a chip-removing tool;

[0040] FIG. 9 shows a cross sectional view of the cutting head from FIG. 8;

[0041] FIG. 10 shows a perspective view of a cutting head of a third embodiment of a chip-removing tool; and

[0042] FIG. 11 shows a cross sectional view of a bore, which opens into a cylindrical recess.

[0043] FIGS. 1 to 7 show a preferred first embodiment of a rotationally driven, chip-removing tool 10 according to the invention, which is embodied in the form of a reamer for example.

[0044] The tool 10 has a shaft 20, a cutting head 30, a fluid channel 21 and two puncture channels 50.

[0045] The shaft 20 serves the purpose of clamping the tool in a clamping chuck or the like. FIGS. 1, 2 and 3 show that the diameter of the shaft 20 tapers in the direction of the cutting head 30. The diameter of the tapered longitudinal section 22 of the shaft 20 is smaller than the nominal diameter of the cutting head 30. The longitudinal section 22 of the shaft 20, the diameter of which is tapered, ensures an elasticity of the tool 10, which facilitates a radial deflection of the cutting head 30.

[0046] The cutting head 30 sits axially on the tapered longitudinal section 22 of the shaft 20. The cutting head 30, which is straight-fluted in the shown embodiment, has three cutting wedges comprising three cutters 31, which extend in a straight line in the axial direction and which carry out a cutting process on the basis of a relative movement between the tool 10 and a workpiece to be processed, and which lie on a virtual cylindrical rotational surface 40 (see FIG. 4). The diameter of the virtual cylindrical rotational surface 40 corresponds to the nominal diameter of the cutting head 30 of the tool 10. The cutting head 30 furthermore has a cutting wedge- and flute-free surface region 32, in which no cutting wedge and no flute is located and which thus does not carry out a cutting process.

[0047] The tool 10 furthermore has an interior fluid channel 21, which is closed on the cutting head side and which extends through the shaft 20 along the longitudinal central axis 11 into the cutting head 30, and from which two radial puncture channels 50 originate in the region of the cutting head 30. The puncture channels 50 are arranged in such a way that they open with an opening 51 into a dynamic pressure active surface 60, which lies inside the cutting wedge- and flute-free surface region 32, as it is shown in FIG. 4.

[0048] In the shown embodiment according to FIGS. 1, 3, 4, 6 and 7, the dynamic pressure active surface 60 is an even rectangular surface, which runs parallel to the longitudinal central axis 11 and which is radially recessed relative to the rotational surface 40 of the cutting head 30. The dynamic pressure active surface 60 thus lies radially inside the virtual rotational surface 40. The radial distance r of the dynamic pressure active surface 60 from the longitudinal central axis 11 is smaller than the radius R of the virtual cylindrical rotational surface 40, the diameter of which corresponds to the nominal diameter of the tool 10. FIGS. 1 and 3 show that the dynamic pressure active surface 60 extends in the axial direction across the entire length of the cutting head 30, thus has the same axial length as the cutting head 30. FIGS. 1 and 3 further show that this dynamic pressure active surface 60 is larger than the sum of the flow cross sectional surfaces of the puncture channels 50 at the openings 51.

[0049] FIG. 4 shows that the dynamic pressure active surface 60 lies at least essentially opposite the center of the cutting wedge partial region 33, which has a segment-shaped cross section, in which the cutting wedges comprising cutters 31 are arranged. The dynamic pressure active surface 60 is advantageously arranged essentially perpendicularly to the angle bisector of the cutting wedge partial region 33, which has a segment-shaped cross section, or of the segment, respectively, of the cutting wedge- and flute-free surface region 32.

[0050] FIG. 4 furthermore shows that the jacket surface of the cutting wedge- and flute-free surface region 32 in the shown embodiment has two cylindrical rotational surface sections 32a, 32b and the dynamic pressure active surface 60.

[0051] The cutting wedge- and flute-free surface region 32 provides for a distribution of the fluid, which escapes at the openings of the puncture channels 50, in the region or volume between the tool 10 and the opposite inner wall of the recess 2 of a workpiece to be processed, via the dynamic pressure active surface 60. Assuming a sufficient fluid supply into the fluid channel 21, the dynamic pressure, which builds up in this region or volume, of the fluid, which leaves the openings 51 of the puncture channels 50, acts on the dynamic pressure active surface 60, whereby a radial force is created, which effects a deflection of the cutting head 30 in the direction of the cutting wedges with cutters 31.

[0052] As a result of the radial deflection, the cutters 31 of the cutting wedges move essentially on a circular path around the longitudinal central axis 11. It has been shown that it is possible in this way to remove a burr or residual chips, which may be present, respectively, in a bore 1, which opens laterally into a cylindrical recess 2 for example, in a gentle and nonetheless reproducible and reliable manner, without running the risk that further residual chip formation occurs at a different location.

[0053] On its side facing away from the shaft 20, the cutting head 30 of the tool 10 furthermore has a gate 34, which is known per se.

[0054] The chip-removing tool 10 according to the invention is thus characterized in that the dynamic pressure active surface 60 is provided in such a way that the sum of the dynamic pressure forces created in the region of the dynamic pressure active surface 60 between the cutting head 30 and the inner wall of the recess 2 can radially deflect the shaft 20 in the direction of the cutting wedges with cutters 31. As already mentioned, condition for this is that the amount of fluid supplied into the fluid channel 21 is sufficiently large, so that a stationary flow state can set in the region or volume between the cutting head 30, in particular the dynamic pressure active surface 60 of the cutting wedge- and flute-free surface region 32, and the opposite inner wall of the recess 2. A sufficiently large fluid supply can readily be realized from a machine tool-related aspect.

[0055] FIGS. 8 and 9 show a second embodiment of a chip-removing tool according to the invention. The second embodiment differs from the first embodiment only by the shape of the dynamic pressure active surface 160. In the second embodiment, the dynamic pressure active surface 160 is formed as an axial groove, which has a convex cross section in the direction of the puncture channel.

[0056] FIG. 10 shows a third embodiment of a chip-removing tool according to the invention. The third embodiment differs from the first embodiment by the length of the dynamic pressure active surface 260. Even though the dynamic pressure active surface 260 has the shape of an even surface, as in the case of the first embodiment, the axial length of the dynamic pressure active surface 260 in the third embodiment is smaller than the axial length of the cutting head 30. The dynamic pressure active surface 260 ends at an axial distance upstream of the front and shaft-side end of the cutting head 30. This results in a type of pocket-like space between the cutting head 30 and the inner wall of the recess 2 to be processed. The axial discharge of the fluid along the cutting wedge- and flute-free surface region or the dynamic pressure active surface 260, respectively, of the chip-removing tool is impeded thereby and the dynamic pressure is increased.

[0057] In the embodiments shown in FIGS. 1 to 10, the dynamic pressure active surface 60 is arranged axially parallel to the longitudinal central axis 11 of the chip-removing tool 10. Said dynamic pressure active surface, however, can also be arranged at an angle to the longitudinal central axis of the chip-removing tool.

[0058] In contrast to the shown embodiments, the dynamic pressure active surface can have the shape of a concave or convex surface.

[0059] It is also possible that a number of differently oriented dynamic pressure active surfaces are arranged inside the cutting wedge- and flute-free surface regions.

[0060] In contrast to the design of the cutting wedge- and flute-free surface region shown in FIG. 4, the dynamic pressure active surface can be radially recessed farther, whereby the two cylindrical rotational surface sections decrease and the dynamic pressure active surface increases. The dynamic pressure active surface can be recessed to the extent that the jacket surface of the cutting wedge- and flute-free surface region can essentially only still consist of dynamic pressure active surface.

[0061] More or fewer than three cutting wedges can furthermore be arranged in the cutting wedge partial region.

[0062] The chip-removing tool can likewise have more or fewer than two puncture channels. The course of the puncture channels from the central fluid channel to the openings lying in the cutting wedge- and flute-free surface region can on principle be designed arbitrarily.

[0063] The chip-removing tool can furthermore also have a number of fluid channels, which run in the shaft, e.g. parallel, and which each lead to a paired puncture channel.

[0064] In addition to its side, which faces away from the shaft, the chip-removing tool can on principle also have a section on its side of the cutting head, which faces the shaft, so that the chip-removing tool can also be used to deburr the interior outlet of a recess, into which the chip-removing tool is inserted.

[0065] It is also irrelevant, how the dynamic pressure active surface was created on the cutting head. For example in the case of the tool specified in DE 103 21 670 A1, a cutting wedge-free and flute-free surface region or a dynamic pressure active surface, respectively, can be created easily in that a surface region, in which a part, which is limited in the axial direction and/or in the circumferential direction, of one or a number of cutting wedges are removed, is created on the cutting head in a region, in which an opening of at least one puncture channel lies, by means of a grinding or another machining.

[0066] The cutting wedge- and flute-free surface region obtained in this manner then has a dynamic pressure active surface, in which the opening of the at least one puncture channel lies and the surface content of which is larger than the flow cross sectional surface of the at least one puncture channel. In contrast to the design shown in FIG. 4, the jacket surface of the cutting wedge- and flute-free surface region can consist only of dynamic pressure active surface.

[0067] In the shown embodiments, the chip-removing tool is realized for example as a reamer. It can, however, also be realized as a stationary cutting tool, e.g. as turning tool, or as a cutting tool, which rotates around a longitudinal central axis as rotational axis, e.g. as a milling, drilling, in particular deep hole drilling, straight-fluted drilling or spiral drilling tool.