DE102008022945A1 - Drilling tool, in particular twist drills - Google Patents

Abstract

In a drilling tool, in particular a twist drill, in particular for drilling rock, comprising a tool-side mounting end, a workpiece-side cutting end and an intermediate cutting part having at least one main spiral groove extending along the cutting part, defined by a substantially constant spiral pitch, and at least one along the cutting part extending, limited by the at least one Haupwendelnut, part-cylindrical and / or partially conical Wendelstegaußenfläche, it is provided that in the Wendelsteg outer surface a plurality of groove sections are formed, which extend transversely to the direction of Hauptwendelnutsteigung.

Description

The The invention relates to a drilling tool, in particular a twist drill, especially for drilling rocks. Such a drilling tool is usually shaft-shaped, with the outside an outlet shaft usually evenly cylindrical is. An attachment end of the drilling tool may also be tapered be to a particularly accurate axial position of the drilling tool set relative to the drill drive.

The Boring tool is usually with a Spanende or Drill head provided, which may be through a hard metal plate reinforced in a slot at the end of the drilling tool inserted and attached. Mark the drill bit or chipping itself by a main cutting angle, which is usually between 100 ° and 150 °.

At the Applying the drilling tool initially engages the cutting end into the workpiece, and - while continuing Drilling also occurs between the attachment end and the chipper lying cutting part with the workpiece in engagement, whereby cleared a cylindrical hole in the workpiece becomes.

The cutting part forming the major part of the drilling tool usually has two main helical grooves extending along the cutting part, over which, as is known, drill dust is to be transported away from the cutting end. Furthermore, the known cutting part forms a longitudinally extending portion of the cutting, bounded by the two Hauptwendelnuten, part-cylindrical or partially conical Wendelstegaußenfläche, which usually extends parallel with the same pitch and between two Hauptwendelnute. Of the partially cylindrical Wendelstegaußenfläche the cutting part is formed at the transition to the respective main spiral groove with a step-shaped profile jump, through which a helically extending edge or cutting edge is formed. Viewing the cross section of the drill, the helical ridge outer surface extends along the constant outer diameter of the cylindrical shaft body of the drilling tool. To increase the drilling efficiency of the drilling tool, a variety of types of drilling tools are known. For example, it is off DE 20 2005 016 682 U1 a drilling tool known whose main spiral groove is stepped at the side facing the drill head groove edge. The individual stages run with the same pitch within the main spiral groove.

EP 0 685 629 B1 discloses a rock drill in which two mutually parallel discharge grooves are incorporated in the drill shank. In this way, two parallel Abfuhrnuten be provided with different groove cross-sections.

Out DE 297 23 908 U1 is a rock drill with a divided into several parallel, separate Bohrnutabschnitte Hauptwendelnut known, the Bohrnutabschnitte are separated either by annular elevations or corresponding recesses each having the same pitch. Also DE 103 42 817 A1 discloses a drill having a main helical groove in which a plurality of helical, parallel to the main helical groove extending annular projections are incorporated, through which a plurality of Bohrnutabschnitte parallel course are formed.

All the known, aforementioned Bohrwerkzeugausführungen suffer from the disadvantage of having the additional profiling to form larger or separate, helical Bohrnute the strength of the drilling tool is not negligible is. Form through the additional spiral groove sections Voltage peaks at the through the Wendelnutabschnitte and the associated material weakening characterized Cutting part of the drilling tool, which spikes to a lead to premature failure of the drilling tool can.

It object of the invention, the disadvantages of the prior art to overcome, in particular a drilling tool of the generic Develop such a way that the drilling efficiency is increased, without the fatigue resistance of the drilling tool to impair.

These The object is solved by the features of claim 1.

According to the invention, a plurality of groove sections, which extend transversely or at a non-negligible angle, in particular from 20 ° to 90 ° to a pitch direction of the main helical groove, are incorporated in the part-cylindrical helix web outer surface, in particular on one or more imaginary helical paths around the cutting part of the drilling tool. The individual groove sections preferably run straight on the spiral web outer surface and in particular have a constant groove radial depth and / or groove width and / or groove length. The plurality of groove sections may be concentrated on a closed ring track to the longitudinal axis of the drilling tool. An arrangement of the plurality of groove sections along one or more imaginary helical paths has proven to be more advantageous, in particular compared to the arrangement of the plurality of groove sections on a closed loop, as the fatigue strength in the helical path-like arrangement is higher. It turned out that in the arrangement of the Grooved portions on a closed loop track, the operating induced stress peaks in the material defining the plurality of groove portions are higher than in the helical arrangement of the plurality of groove portions. Experiments showed that the drilling efficiency can be significantly increased with the measure according to the invention. The transverse to Haupwendelnut more groove sections in the Wendelstegaußenfläche cause a significant reduction in the friction between the workpiece and the drilling tool, which on the one hand less drive energy must be introduced into the drilling tool on the other surprisingly, the drilling tool is far less thermally stressed. It has also been found that impairment of the fatigue strength of the drilling tool is not noticeable due to the groove sections according to the invention in the spiral web outer surface, where the drilling tool is formed most strongly in sections.

at a preferred embodiment of the invention extend the multiple groove sections with a much larger one Circumferential direction component as axial direction component. It is clear that the ring sections also exclusively in the axial direction can extend. However, it turned out that one dominant circumferential direction component in terms of drilling efficiency more advantageous is.

at A preferred embodiment of the invention are the several Groove sections arranged parallel to each other. Because of the parallel Arrangement and the necessarily associated distance the multiple groove sections to each other it is possible to increase the drilling dust removal effect of the multiple grooves without weakening the drill too much.

Preferably each of the plurality of groove portions extends from one the cutting facing edge of the main spiral groove to a mounting end facing edge of the main spiral groove, in particular linearly circumferential. Preferably extend from one edge to the other the shortest Path along the spiral web outer surface.

at a preferred embodiment of the invention are the several Groove sections on at least one imaginary common secondary spiral path, whose pitch is smaller than the main coil groove pitch. The helical pitch is defined by an axial width (in mm) of a full circumference 360 ° rotation of the helix. Preferably, the slope of the at least one secondary spiral path that is smaller than the main spiral path slope, that the helical course of the Nebenwendelbahn at a Circulation at least once, preferably several times, in particular more than five or ten times, interrupted by the main spiral groove is. In the arrangement of the multiple groove sections on a single, along the drilling tool extending helical path different Slope to Hauptwendelnutsteigung optimal fatigue strength results achieved, the drilling efficiency due to improved Bohrmehlabtransports and a reduction of the thermal load of Drilling tool can be increased.

at a preferred embodiment of the invention is the Hauptwendelbahnsteigung at least twice, in particular five times, preferably Ten times, especially twelve or fifteen times greater than the helical pitch of the imaginary secondary helix, on the several exclusively in the Wendelstegaußenfläche introduced groove sections are positioned.

Preferably remain the helical pitch of the imaginary Nebenwendelbahn and / or the helix pitch of the main helical groove along the entire axial extent of the cutting part constant. In this way, one can essentially Continuous and blockage-free removal of drilling dust longitudinally the main spiral groove and the plurality of groove sections can be achieved.

at A preferred embodiment of the invention is in a Diameter of the cylindrical shaft body of the drilling tool, in particular the part-cylindrical spiral web outer surface, of 5 mm, 6 mm, 6.5 mm, 7 mm, 8 mm, 9 mm or 10 mm a helical pitch the imaginary Nebenwendelbahn in a range of 0.5 mm to 3 mm, preferably from 1 mm to 2.5 mm, preferably from 1.5 mm to 2.5 mm, selected. In particular, the spiral pitch the main spiral groove in a range of 15 mm to 40 mm, preferably 22 mm to 30 mm, to be determined.

at a development of the invention is a width of the plurality of groove sections and / or a radial depth of the plurality of groove portions smaller as a groove width of the main spiral groove or a radial depth of the Main helical. The groove width is defined by the shortest Distance between two opposite edges the main spiral groove at the radial level of the cylindrical outer land surface between two main spiral grooves. The radial depth of the main spiral groove is defined by the radial distance of its radial low point to the partially cylindrical outer web surface between two adjacent main spiral grooves.

Preferably, a radial depth of the plurality of groove sections is less than 1 mm, preferably less than 0.5 mm, in particular equal to 0.1 mm. A width of the plurality of groove portions may be smaller than 1 mm, in particular equal to about 0.5 mm, 0.6 mm or 0.7 mm.

at A preferred embodiment of the invention are the several Groove portions interrupted by the at least one Hauptwendelnut on an imaginary (uninterrupted) Nebenwendelbahn. The the several auxiliary sections occupying Nebenwendelbahn winds itself in particular substantially over the entire axial length of the cutting part.

Preferably opens the secondary spiral path occupying the several groove sections essentially in the drilling end, either one of the groove sections opens at the drilling end or at least in a very close Distance at the end of drilling ends.

at a development of the invention opens each groove section from one main turning edge into the adjacent, opposite one Hauptwendelnutrand.

at a development of the invention is the helical pitch direction the imaginary Nebenwendelbahn either opposite or preferably rectified to the helical pitch direction of the main helical groove.

Further Features, features and advantages of the invention are achieved by the following description of a preferred embodiment of the invention with reference to the accompanying drawings, in which demonstrate:

1 a side view of the drilling tool according to the invention; and

2 a cross-sectional view of the drilling tool according to 1 along the section line II-II.

In the 1 and 2 is the twist drill according to the invention generally with the reference numeral 1 Mistake. The twist drill 1 has a substantially cylindrical stem basic shape.

The twist drill 1 forms an attachment end 3 , which is cylindrical and end recesses 5 . 7 to ensure a defined position with respect to the drilling tool drive (not shown). The cylindrical attachment end 3 extends over substantially a quarter to a third of the total length of the twist drill 1 ,

At the attachment end 3 in the axial direction X closes the cutting part 11 at, whose maximum cylindrical outer diameter is slightly smaller than that of the attachment end 3 is.

In the ideal cylindrical body of the cutting part at the beginning of the production process of the twist drill 11 are two parallel spiral main spiral grooves 13 . 15 incorporated, which at constant pitch along the cutting part 11 towards a drill bit or chipper 17 of the twist drill 1 extend defining at least two main cutting edges.

Between the main spiral grooves 13 . 15 two remain apart from each other through a main spiral groove 13 . 15 spaced apart and parallel to each other, part-cylindrical Wendelstegaußenflächen 21 . 23 the cylindrical base body of the cutting part at the same pitch as the two Hauptwendelnute 13 . 15 , The width (shortest distance from two opposite boundary edges of a spiral web outer surface 21 . 23 ) of each spiral land outer surface 21 . 23 corresponds essentially to the width (shortest distance of the opposite, the main spiral groove 13 . 15 bordering edges) of the main helical groove 13 . 15 , The spiral pitch (axial width at a full circumferential 360 ° circulation of the helix) of the Wendelstegaußenflächen 21 . 23 and the main spiral grooves 13 . 15 is about 20 to 30 mm.

In both part-cylindrical Wendelstegaußenflächen 21 . 23 is an interrupted Nebenwendelbahn recognizable by several, equally long groove sections 27 is formed. The groove sections 27 occupy the Nebenwendelbahn constant pitch, and with respect to the circulation of the Nebenwendelbahn are the multiple groove sections 27 indicated in alignment with each other. The spiral pitch of the multiple groove sections 27 is significantly smaller than that of the main spiral groove 13 . 15 or the Wendelstegaußenflächen 21 . 23 ,

The constant spiral pitch of the interrupted secondary spiral path is about 1.5 to 2 mm in a 360 ° circulation. Each groove section 27 the secondary spiral path has a radial depth of about 0.1 mm and a width of about 0.5 to 0.7 mm.

The individual groove sections 27 lie parallel to one another and have a significantly larger circumferential direction component than the axial direction component. The circumferential direction component is slightly smaller than a right angle to the axial direction X.

As in 1 it can be seen, each groove section opens 27 at an angle of 30 ° to 60 ° at the transition edge between the spiral web outer surface 21 . 23 and the respective main helical groove 13 . 15 into the main spiral groove 13 . 15 , what in 2 through the asymmetrical nostril of the Rillenabschnit th 27 is indicated. As in 2 it can be seen that both have major meanings 13 . 15 a convex groove bottom.

The Nebenwendelbahn is due to the small helix pitch several times through the Haupwendelnut 13 . 15 interrupted, each groove section 27 the Nebenwendelbahn from a Hauptwendelnutrand in the opposite edge opens continuously kinking extending.

It turned out that when passing through the groove sections 27 defined Nebenwendelbahn reinforced with respect to the Hauptwendelnutsteigungsrichtung same direction of slope of the removal of drilling dust and the friction between the Wendelstegaußenfläche and the workpiece can be significantly reduced. The heat removal from the drilling tool is also achieved by the fan-like arrangement of the interrupted groove sections according to the invention 27 improves, because the groove sections by generating air turbulence on the outside of the twist drill 1 cause its cooling.

The in the foregoing description, figures and claims disclosed features can be used both individually and in any combination for the realization of the invention be important in the various embodiments.

1

twist drill

3

attachment end

5, 7

recesses

11

cutting part

13 15

main helical

17

machining

21 23

Helix web outer surfaces

27

groove portions

X

axially

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 202005016682 U1 [0004]
• EP 0685629 B1 [0005]
• - DE 29723908 U1 [0006]
• - DE 10342817 A1 [0006]

Claims (15)

Drilling tool, in particular spiral drill, in particular for drilling rock, comprising a tool-side attachment end ( 3 ), a workpiece-side cutting edge ( 17 ) and an intermediate cutting part ( 11 ) with at least one along the cutting part ( 11 ) extending main helical groove ( 13 . 15 ), which is defined by a substantially constant spiral pitch, and at least one along the cutting part ( 11 ), through which at least one main spiral groove ( 13 . 15 ) limited, part-cylindrical and / or partially conical spiral web outer surface ( 21 . 23 ), characterized in that in the spiral web outer surface ( 21 . 23 ) a plurality of groove sections ( 27 ) are formed, which extend transversely to the direction of Hauptwendelnutsteigung. Drilling tool according to claim 1, characterized in that the plurality of groove sections ( 27 ) are arranged parallel to each other. Drilling tool according to claim 1 or 2, characterized in that the plurality of groove sections ( 27 ) each of a the Spanende ( 17 ) facing edge of the main spiral groove ( 13 . 15 ) to a fixing end ( 3 ) facing edge of the main spiral groove ( 13 . 15 ). Drilling tool according to one of the preceding claims, characterized in that the plurality of groove sections ( 27 ) lie on at least one common secondary spiral path whose pitch is smaller than the Hauptwendelnutsteigung. Drilling tool according to claim 4, characterized in that the slope of the at least one secondary spiral path is smaller than the Hauptwendelnutsteigung that the helical course of the Nebenwendelbahn at least once, preferably several times, in particular more than five or ten times, by the Hauptwendelnut ( 13 . 15 ) is interrupted. Drilling tool according to claim 4 or 5, characterized that the Hauptwendelbahnsteigung by at least two times, in particular Five times, preferably ten times, in particular twelve times or fifteen times, greater than the Nebenwendelbahnsteigung is. Drilling tool according to one of claims 4 to 6, characterized in that the Nebenwendelbahnsteigung and / or the at least one Hauptwendelnutsteigung along the cutting part ( 11 ) remain unchanged. Drilling tool according to one of claims 4 to 7, characterized in that at a diameter of the drilling tool 5 mm, 6 mm, 6.5 mm, 7 mm, 8 mm, 9 mm or 10 mm a Nebenwendelbahnsteigung in a range of 0.5 mm to 3 mm, preferably 1 mm to 2.5 mm, preferably from 1.5 to 2 mm, in particular the main helical pitch in a range of 15 mm to 40 mm, preferably from 20 mm to 30 mm. Drilling tool according to one of the claims, characterized in that a width of the plurality of groove sections ( 27 ) and / or a radial depth of the plurality of groove sections ( 27 ) is smaller than a Hauptwendelnutbreite or Hauptwendelnutradialtiefe. Drilling tool according to one of the preceding claims, characterized in that a radial depth of the plurality of groove portions ( 27 ) is less than 1 mm, preferably less than 0.5 mm, in particular equal to about 0.1 mm. Drilling tool according to one of the preceding claims, characterized in that a width of the plurality of groove sections ( 27 ) is less than 1 mm, in particular equal to about 0.5 mm, 0.6 mm or 0.7 mm. Drilling tool according to one of the preceding claims, characterized in that the plurality of groove sections ( 27 ) interrupted by the at least one main spiral groove ( 13 . 15 ) on a secondary spiral path ( 27 ), wherein the secondary spiral path defined by the plurality of groove sections (FIG. 27 ) in particular constant pitch substantially over the entire axial length of the cutting part ( 11 ) winds. Drilling tool according to claim 9, characterized in that the plurality of groove sections ( 27 ) forming secondary spiral path opens substantially into the boring. Drilling tool according to one of the preceding claims, characterized in that each groove section ( 27 ) opens from a Hauptwendelnutrand in the opposite main spiral groove edge. Drilling tool according to one of the preceding claims, characterized in that the Nebenwendelbahnsteigungsrichtung towards the main helical groove pitch direction, or preferably is rectified.