DE1970334U - SPACES. - Google Patents

Description

RA.254122-9.5.6

PATENT Attorney DIPL.-ING. W. WEINKAUFF FRANKFURT A. M. GEORG-SPEYER-STRASSE 1

Production Engineering Research Association of

Great Britain, Arthur Ivan V / alter Moore and

John Howard Porter, Leicestershire, Great Britain

Clears) ear him

British Priorities 28 490/61

v. 4.8o61 and 19 913/62 BC May 23, 62

The invention "relates to reamers whose teeth according to the invention each have a back with a circular cross-section, from which a so-called second (auxiliary) Open space closes. The cutting edge of each tooth is formed on a flat cutting surface which runs at an acute angle to the leading edge of the round back and thus a small one with the second open area Forms guide angle, the second open area runs so that your clearance angle decreases from the outer corner to the leading end of the cutting edge.

The cut surface is expediently flat.

The invention may be further explained with the aid of the exemplary embodiments shown schematically in the figures will. Show it:

Figure 1 is an end view of the leading edge of a tooth to a drill with straight axially parallel Ribs;

/ 2

Figure 2 is a plan view of Figure .1;

FIG. 3 shows a side view of Ligur 1;

FIG. 4 shows a graphical representation full straight rib drill bits;

FIG. 5 shows a side view of a broach with spiral ribs; for open bores;

FIG. 6 shows a side view of a reamer for blind holes.

Figures 4 ″ to 6 are based on a smaller scale than Figures 1 to 3 °

As can be seen from Figures 1 to 5, the tooth has a back 11 of a circular profile, on which a Auxiliary open space 12 and then an additional open space connect. The cutting edge 14 is formed by grinding in a flat cutting surface 15 at an acute angle to the leading edge of the round back. Furthermore, a frontal conical inclined surface 16 is at the centering end of the reamer ground in.

Since the auxiliary clearance area 12 is below the bore 17 of the broach must run, it forms a small radial angle with the cutting surface 15, which is designated by 29 in FIG.

The (radially) outer corner of the reamer is the end 18 of the cutting edge 14, which describes the full diameter 17 of the associated bore. According to the invention, this outer cutting corner 18 is not located at the intersection 19 between the cutting surface 15 and the leading edge 21 of the round back 11, but rather on the connecting line 22 between the round back and the auxiliary clearance surface 12. This protects the outer cutting corner 18; it cannot become blunt _s when the leading edge 21 of the round back wears off »

All of the cutting work of the reamer is done by the cutting edges 14, and these can be seen from the negligible.sn wear and tear of the round back, can be completely renewed by regrinding.

In particular, the regrinding results in a complete renewal of the worn outer cutting corner 18, so that the drill becomes as good as new with regard to the cutting effect. Very little material has to be sanded off so that the drill can be sharpened frequently and is as good as new every time. Since the Tooth flanks do not have to be reground, inaccurate regrinding only has a slight effect on the Lip level off.

The auxiliary open space 12 is expediently chosen so wide that that their clearance angle of a maximum value corresponding to the depth of cut, the size and nature of the drill, along the cutting edge 15 to the inner end 30 of which is approximately EuIl. The low or weak negative Clearance angle at this point causes a suppression

hitting and rattling when drilling.

The above-mentioned decrease in the lateral angle of the rear edge of the son is achieved in accordance with the drawings by making the auxiliary clearance area through straight cuts is determined in imaginary planes perpendicular to the leading edge. In the case of a straight-finned drill, there is one Grind in a flat auxiliary surface parallel to the drill axis. Ss is suitable for every drill size Provide different depths of cut, with a flat auxiliary surface in a suitable clearance angle immediately behind the round back is a suitable minimum value of the ireiwinkel, approximately zero, on a circumferential distance which is smaller than the radian measure on a conventional drill tooth. The additional Flank 13 avoids a strongly negative clearance angle and its unfavorable influence on the grinding process; it is also through straight tracks with imaginary normal planes to the leading edge of the Bohreij tooth definitely. In the lalle of a straight-ribbed broach, the additional open space is in turn in a Plane parallel to the drill axis.

As can be seen from Figures 1 to 3, the conical inclined surface 16 is ground back so far that the Cutting edge H straight at corner 30 of the auxiliary flank 12 ends with the additional open area 13. However, the conical free surface 16 does not have to be so / far be sanded back; it can be a compound Cutting edge be produced from the penetration of the cutting surface 15 with the two surfaces 12, 13? and

the composite cutting edge can be limited by the conical bevel surface, which the Length of this part of the cutting edge between surfaces 15 and 15 determined instead of eliminating it, as in Figures 1 to 3 «

The conical inclined surface supports centering when inserting the reamer into the pre-drilled hole, reducing the risk of damage to the drill teeth is eliminated «When using a conical inclined surface, part of the cutting work can be done by its cutting edges 23 can be taken over with the tooth flanks | the Flanks behind these cutting edges do not have a clearance angle, which in turn causes hammering and chattering of the drill is suppressed. The cutting edges 14 between the auxiliary clearance surface 12 and the cutting surface should extend over at least three quarters of the depth of cut.

Reaming bits according to the invention, the teeth of which are equally spaced, and the lip height error of which is negligible are small without the conical inclined surfaces 16 holes, the quality of which for certain needs is useful. Greater demands on the quality and dimensional accuracy of the bores with minimal Striking and chattering have to be met by unequal tooth spacing and / or low manufacturing tolerances with regard to the lip heights and / or by the conical inclined surfaces 16,

Straight-ribbed drills according to FIG. 4 or left-handed ribs are used for open bores

with corresponding hats 25 , as in Figure 5 _} or even slightly right-handed spiral ribs. The helix angle is not critical, it is normally dimensioned to be no more than 10 °. The cutting surface is then left-handed at an angle between 10 ° and 30, generally not more than 20. The type of drill shown in FIG. 6 with right-hand spiral grooves is used to machine blind holes, but the cutting surface 28 is also right-handed, and a relatively large spiral angle between 20 and 60, generally not more than 35 °, is used. A suitable angle of attack for the associated cutting surface is between 15 ° and 30 °, generally not less than 20. The references to the gear direction assume that the drill, viewed from the rear, rotates clockwise when working. In all cases, the helix angle and the angle of the cutting surface should be selected in the specified ranges, so that the protected position of the radially outer cutting corner 18 is achieved, as described for FIGS. 1 to 3 «

Such a reaming drill tends to work out slightly narrower holes than corresponds to its diameter, so that a polishing effect arises between its round back surfaces and the wall of the bore. With some materials this results in a surface improvement, while other materials tend to to adhere to the round back surfaces of the drill, whereby notches can be torn in the broached hole. This undesirable effect can be with two things are encountered: once, by using the broach

subjected to appropriate treatment, for example steaming if it is is a high-speed steel drill bit; on the other hand, the radial position of the cutting surface 15 can be varied accordingly while the angle of attack is maintained «

The exemplary embodiments described above apply directly to machine tools; in the When used as hand tools, the angles of the cutting surfaces and auxiliary free surfaces would have to be chosen in such a way that that there are very small guide angles.

Claims (12)

BA. 254122 * -3.5.67 - 8 - '' claims 1.) Räumbohrer, characterized in that its Teeth each have a back (11) with a circular profile and a subsequent auxiliary free surface (12) form, wherein the cutting edge (14) of each tooth arises on a cutting surface (15) and one includes acute angle (29) with the leading edge of the round back (11) and so with the auxiliary clearance area forms a small lead angle, where the auxiliary flank (12) runs so that its clearance angle from the radially outer cutting corner (30) to the leading end (18) of the cutting edge decreases. 2.) Drill according to claim 1, characterized in that the cutting surface (15) is flat « 3.) Drill according to claim 1 or 2, characterized in that the auxiliary clearance surface (12) has a clearance angle which decreases along the cutting edge to zero by appropriate width measurement _e 4 «) Drill according to one or more of the preceding Claims, characterized in that the auxiliary open area (12) is determined by straight tracks in imaginary normal planes to the leading edge of the tooth « 5 °) drill according to claim 3 or 4? marked by a gEmui additional open space (13) behind the line (31)? along which the auxiliary clearance area reaches the clearance angle lull. 6.) Drill according to claim 5, characterized in that ^k the additional free surface (13) by approximately straight tracks with imaginary planes perpendicular to the leading edge. 7.) Drill according to one or more of the preceding claims, characterized by conical end faces (16). 8.) A drill according to claim 7 in "conjunction with claim 5 or 6, characterized in that the conical end faces (16) are as far back ground _s that the cutting edge (14) between the additional clearance face (13) and the cutting surface (15) is limited " 9.) Drill according to claim 7 in conjunction with claim 5 or 6, characterized in that the conical end faces (16) are ground back so far that that the cutting edge (14) on the cutting surface (15) only up to the point of intersection; (31) with the helpless free area (12) and the additional open area (13) goes. 10.) Drill according to one or more of the preceding Claims, characterized by unequal distances between its teeth. ο ) Drill according to one or more of the preceding claims, characterized by regulated deviations in the lip height of the teeth. 12.) Drill according to one or more of the preceding Claims characterized by straight ribs » 13 ») drill according to one or more of claims 1 to 11, characterized by right-handed Spiral ribs and right-hand cutting surfaces. 14 ») Drill according to one or more of the preceding claims j characterized by the application of Means (steam) to reduce the sticking of material of the bore wall to the round ones Back (11). 15 ·) Drill according to one or more of the preceding Claims j characterized by such a radial adjustment of the cutting surfaces (I5) j that the Adhesion of material to the back (11) becomes a minimum.