JPS6384807A - Drill - Google Patents

Abstract

PURPOSE:To prevent the shift of a rotary center due to a walking phenomenon in a cutting process and an increase in cutting resistance, and obviate thinning by forming an approximately U-shaped recess of sub-groove at the center side of the heel face of a cutter and applying a small web thickness and a small chisel edge. CONSTITUTION:A drill 11 has a standard tooth form within a predetermined range in an axial direction in such a way that a heel face 11b and a cutting edge back face 11a constituting a chip discharge groove 6 form smooth curvature at the section of a drill axis. And a sub-groove 11c is formed, approximately U-shape recessed from the heel face 11b to the center thereof and extending about 0.5-1.1 times a drill diameter in an axial direction, and each heel part 11d is shaved, thereby enlarging the space of the chip discharge groove 6 and improving the permeability of cutting oil. Therefore, chips generated via a cutting process with the cutting edge of the drill 11 appear along the cutting edge back face 11a and the chips pressed with a chisel edge are guided together from the sub-groove 11c to the discharge groove 6, thereby being discharged outside.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to drills, and more particularly to drills that essentially do not require thinning.

BACKGROUND OF THE INVENTION Conventionally, in order to increase the efficiency of hole drilling using a drill, a drill 2 with increased rigidity is used to drill holes in the direction perpendicular to the drill axis, as shown in Fig. 3. In the cross section of the blade part, the blade back surface 2b and heel surface 2c are each formed thicker than the standard drill 3 shown by the dotted line 3 in the figure,
The core thickness is increased to provide rigidity.

Problems to be Solved by the Invention However, with the structure described above, since the core thickness is large, the chisel edge becomes larger than that of the standard drill 3 when the cutting edge is sharpened, resulting in a so-called walking phenomenon, which causes the drill to deteriorate. As the center of rotation moves, the accuracy of hole drilling deteriorates, and the cutting resistance increases, resulting in poor machinability.
．． 16.17 It becomes necessary to accurately perform thinning over a relatively wide area as indicated by diagonal lines in Figures 16 and 17, and there is a problem in that the skill of thinning and hole drilling affect accuracy.

In addition, this thinning must be performed every time re-grinding.
There is also the problem that it is complicated. Furthermore, in response to the increase in core thickness, the cross-sectional area of the chip ejection groove is smaller than that of the standard drill 3, and the chiller mount h ++ scolding I word L 1% − ↓ − n day de skin λJk − ↓ ~ Therefore, an object of the present invention is to provide a drill that can drill holes with high accuracy without thinning and also has good chip ejection properties.

Means for Solving the Problems In order to achieve the above object, the present invention is configured such that a sub-groove communicating with the chip ejection groove is formed in the thick core portion. In other words, for a standard cross-sectional blade shape in which the heel surface and the back surface of the blade that constitute the chip ejection groove form a roughly smooth curved surface in the axial cross-section of the drill, there is a section approximately closer to the center of the heel surface than the heel surface of the standard cross-sectional blade shape. It is configured to have a cross-sectional shape having a U-shaped sub-groove within a predetermined range along the axial direction from the tip.

Effect of the Invention With the above configuration, during cutting, the tip of the drill does not perform a so-called walking phenomenon with respect to the material to be cut, and the center of rotation of the drill does not move, and the cutting resistance is also reduced, making it possible to drill holes with high precision. On the other hand, in the drill axial cross section,
Chips crushed by the chisel edge are well discharged from the above-mentioned sub-groove through the chip ejection groove, and a part of chips generated by cutting with the cutting blade is well ejected through the above-mentioned sub-groove and through the chip ejection groove. At the same time, the remaining chips are directly ejected through the chip ejection groove.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail below with reference to the drawings shown in FIGS. 1 to 14.

FIG. 1 is an end view of the blade portion of a drill 11 according to the first embodiment. The drill 11 has a standard cross-sectional blade shape in which the heel surface 11b and the blade back surface 11a forming each chip ejection groove 6 form a substantially smooth curved surface in the axial cross section of the drill, within a predetermined range from the tip end along the axial direction. . This standard cross-sectional blade shape is similar to the cross-sectional blade shape of the conventional standard drill 3 shown by the dotted line in the figure. A sub 111c is formed closer to the center of the heel surface than the heel surface 11b of this standard cross-sectional blade shape, and is recessed in a substantially U-shape and extends along the axial direction. Each heel portion lld is shaved off to enlarge the space of the chip discharge groove 6 and improve penetration of cutting oil.

Therefore, the chips generated by the cutting of the cutting edge of the drill 11 are guided into the chip ejection groove 6 along the back surface 11a of the blade and are efficiently ejected, and the chips crushed by the chisel edge are removed from the above side 'frIllc into the chip ejection groove 6. 6 and is well discharged.

According to the first embodiment, since the heel surface 11b is provided with the sub-groove 11c recessed in a U-shaped cross section on the center side, the chisel edge becomes small and the so-called walking phenomenon does not occur during cutting, and the hole can be drilled with high accuracy. Can be processed. In addition, the chip ejection groove 6 can be made larger than the chip ejection groove of the conventional high-rigidity drill 2 or standard drill 3, and the back surface of the blade 11a
Since the chips can be smoothly guided into the chip ejection groove 6 along the same line, the ejection performance of the chips is improved.

2 and 3 are an end view of the blade part of the drill l and a side view of the drill l according to the second embodiment, respectively. In FIG. 3, dotted lines indicate the heel surface 3b and the blade back surface 3a that constitute the chip ejection groove. and indicates a conventional brocade drill 3 having a standard cross-sectional cutting edge shape with a substantially smooth curved surface in the axial cross-section of the drill, and the two-dot chain line indicates a conventional high-rigidity drill 2 with a large core thickness. Also, the fourth
．． Figures 5.6 and 6 show a cutting edge surface, a cross-sectional side view, and a cross-sectional view taken along the line ■--■ in Figure 5, respectively, of the drill according to the second embodiment.

The drill l is formed symmetrically about the axis O point in FIG. The groove wall surface of each curved chip ejection groove 6 is formed spirally along the direction, and a blade back surface 4 and a heel surface 5 are respectively provided.

The blade back surface 4 is made thicker than the standard drill 3 by projecting into the chip ejection groove 6 in a substantially triangular shape from the standard drill 3 in the axial cross section of the drill to form a protrusion 4c. That is, the outer side 4a of the back surface 4 of the blade protrudes like the conventional high-rigidity drill 2, while the center side 4b is depressed from the center side of the high-rigidity drill 2 to reduce the core thickness.

Further, in the axial cross section of the drill, the heel surface 5 has an outer end 5b that protrudes into the chip ejection groove 6 as in the high-rigidity drill 2, as shown by the dashed line in FIG. , a U-shaped concave sub-groove 5a is formed spirally along the axial direction from the outer end 5b toward the center. Therefore, the outer end 5b of the heel portion 5 is made thicker than the standard drill 3, while the center side is recessed to have a smaller core thickness than the high-rigidity drill 2 and the standard drill 3. Note that the core thickness portion is formed to have a parallel core thickness (0/100) parallel to the drill axis direction. The auxiliary groove 5a is formed within a certain range along the axial direction from the tip side of the drill, and this range is the range in which the cutting edge of the drill l can be reground. In addition, the drill l has a grinding wheel for forming the sub-groove 5a, for example, by grinding off the heel portion 7 as shown by the solid line in FIG. is preferred. In this case, even if the heel portion 7 was shaved off, the life of the drill did not decrease due to the decrease in the rigidity of the drill.

Therefore, chips generated by cutting with the drill 1 are guided into the chip ejection groove 6 along the curved surface of the outer side 4a of the approximately triangular protrusion 4c on the back surface 4 of the blade, and are well discharged, and are crushed by the chisel edge. The waste is guided into the chip discharge groove 6 from the side '7R5a and is properly discharged.

Drill according to the second embodiment above! A specific example of a drill for steel is shown in FIG. Groove width ratio 1 = 1 to 0.8:
1. The core thickness Dl is 0.04 to 0.11D (where D is the drill diameter). Then, the angle α between the line connecting the outer ends of the back surface 4 of both blades and the tangent to the curved surface on the center side of the back surface 4 of the blade is lO°.
~15°, the radius of curvature R of the curved surface on the center side of the back surface 4 of the blade is 0
．． 1 to 0.2D, the diameter D3 of the curved surface from the back surface 4 of the blade to the heel surface 5 is φ0.1 to 0.2D, the radius of curvature R1 of the curved surface on the center side of the heel surface 5 is 0.5 to 0.8D, The distance from the center of the drill, that is, the diameter of the boundary between the outer end 5b of the heel surface 5 and the sub-groove 5a is φ0.85D. The sub-groove 5a has an axial length e (see Fig. 2), that is, the axial length from the contact point of the cutting edge and the sub-groove 5a is 0.5.
~1.1D. If the axial length is this much,
It can be re-ground the same number of times as a conventional drill, and its lifespan is also comparable to that of a conventional drill.

However, in order to extend the service life, the shorter the above length, the better.

In addition, in conventional high-rigidity drills for scrap metal, the shoulder width ratio is 0.8.
~0.9:1. The core thickness was 0.2 to 0.45D, and it was necessary to perform thinning. In addition, standard drills for steel have a groove width ratio of 1.3:1 to 1:11 and a core thickness of 0.1 to 0.
20D, and thinning was necessary in some cases.

In addition, the flute width ratio and core thickness of Drill I are different from the drills for light alloys and aluminum and the steel drills mentioned above, so the flute width ratio and core thickness are determined depending on the application and thinning is performed. We need to make it so that we don't have to do it. For this light alloy,
As a reference example of a drill for aluminum, the groove width ratio is 1.5:
Increase the torsion angle to 1-1.6+1 and set the twist angle to 38 to 42.
There are drills that have a larger core thickness but the same core thickness as steel drills.

According to the second embodiment, since the heel surface 5 is provided with the sub-groove 5a, the core thickness is smaller than that of the standard drill 3 or the high-rigidity drill 2, and as a result, the chisel edge becomes smaller when the blade is raised. At the same time, the so-called walking phenomenon does not occur and holes can be drilled with high precision, cutting resistance is reduced, machinability is improved, and there is no need for thinning.

Therefore, it is possible to reliably solve the problem of the conventional high-rigidity drill 2 in which the skill of thinning affects the precision of hole drilling. Further, there is no need to perform thinning every time the drill is re-grinded, and sufficient cutting can be achieved by simply sharpening the cutting edge at the tip of the drill. In addition, since the sub-groove 5a is provided on the center side of the heel surface 5, the chip ejection groove 6 can be made larger than the chip ejection groove of the conventional high-rigidity drill 2 or standard drill 3, and the protrusion of the back surface 4 of the blade can be made larger. Since the chips can be smoothly guided into the chip ejection groove 6 along the curved surface of the outer side 4a of the portion 4c, the ejection performance of the chips is improved. Moreover, if the outer end 5b of the heel surface 5 is made thick, the protrusion 4 on the back surface 4 of the blade
By forming c and making it thick, drill rigidity can be improved without increasing the core thickness. Furthermore, in response to the reduced core thickness as described above, the cross-sectional area of the chip ejection groove 6 is larger than that of the standard drill 3 or the high-rigidity drill 2, and the chip ejection performance is improved.

Note that the present invention is not limited to the above two embodiments, and can be implemented in various ways.

For example, the thick core portion may be tapered very slightly (0 to 0.5/100) in the axial direction of the drill.

Further, as shown in FIG. 8, a larger taper (1 to 2/100) may be applied to the thick core portion.

Further, as shown in Fig. 9.10, the front part 8 from the tip to the center in the axial direction of the drill has a cross-sectional shape as shown in Fig. 6, while the cross-sectional shape from the center to the rear end is The rear part 9 of the drill has a cross-sectional shape as shown in FIG. 10, and as shown in FIG. ) may be added.

In addition, as shown in FIG. 11, the thick core part of the front part 6 is slightly tapered (O~0.57100) in the axial direction of the drill, and the thick core part of the rear part 9 has a parallel core thickness. (0
/100) may be added.

In addition, as shown in FIG. 12, the front part 8 has a parallel core thickness (0/100), while the rear part 9 has a slightly tapered core thickness (0 to 0.5/IOO). ) may be added.

Furthermore, as shown in FIG. /l 00) may be added.

In addition, as shown in Fig. 14, only the tip 10 is pressed with a grindstone or the like as a cutter, and the remaining part has a parallel core thickness or a --like taper as shown by the two-dot chain line in the figure. You may also add .

In addition, in each of the above modifications, No. 9.11, 12°13
．． The cross-sectional view taken along the VI-Vl line in FIG. 14 is shown in FIG.
An X-ray cross-sectional view is shown in FIG.

According to the above structure, by forming a substantially U-shaped sub-groove on the center side of the heel surface of the blade, the core thickness becomes smaller and the chisel edge becomes smaller, so that when cutting, the so-called The walking phenomenon does not occur and the center of rotation of the drill can be effectively prevented from moving. Furthermore, since the cutting resistance is reduced due to the smaller chisel edge, thinning is not necessary, and the skill of thinning does not affect the accuracy of the hole. Therefore, accurate drilling can be performed without thinning. Further, there is no need to perform thinning every time the drill is re-grinded, and sufficient cutting can be achieved simply by sharpening the cutting edge at the tip of the drill. Furthermore, since the sub-groove is provided on the center side of the heel surface, the cross-sectional area of the chip ejection groove is larger than that of a standard drill or a high-rigidity drill, improving chip ejection performance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the cutting edge of a drill according to the first embodiment of the present invention, and FIGS. 2 and 3 are a side view and a cross-sectional view showing the cutting edge of the drill according to the second embodiment of the invention, respectively. , Figures 4 and 5 are a top view and a cross-sectional side view of the drill bit shown in Figure 3, respectively;
Figure 6 is 5.8,9゜II +') IQ I
Figure 7 of LrEn's Vl-Vl cross section is a more specific view of the tip of the drill blade, Nos. 8, 9, 11.12, 13.1
4 is a sectional side view of a drill according to another embodiment, FIG. 10 is a sectional view taken along the line X-X of FIGS. 9.11 and 12.13,
Figures 15, 16, and 17 are explanatory diagrams of cases in which a conventional high-rigidity drill is thinned. 1.11...Drill according to the embodiment, 2...Conventional drill, 2b...Blade back surface, 2c...Heel surface, 3...
・Standard drill, 3a...Blade back side, 3b...Heel side, 4. lla...Back side of the blade, 4a...Outside, 4b...
・Center side, 4c...Protrusion, 5.1lb--Heel surface, 5a, l1c-minor groove, 5b--Outer end, 6...Chip ejection groove, 7, 11d ...heel part. Patent Applicant: Kobe Steel, Ltd. Agent Patent Attorney: Aoyama Aoyama and 2 others Figure 2 Figure 4 Figure 5 Figure 6 Figure 7v! J t4'58 figure - 15■ 16113 1st
Figure 7 Procedural Amendments Dear Commissioner of the Patent Office, December 14, 1988, 1.
Display of the incident 1988 Patent Application No. 228675! Sh. 2. Name of the invention [゛・Drill 3. Relationship with the case of the person making the amendment Patent applicant address 1-3-18 Wakihama-cho, Chuo-ku, Kobe, Hyogo Prefecture Name (
119) Representative of Kobe Steel Co., Ltd.
Motokichi Kame Taka 4, Agent address: 2-1-61 Mi, Higashi District, Osaka City, Osaka Prefecture 540
Item 7. Contents of amendment (1) The following parts of the specification will be corrected. (A) As shown in the appendix to the scope of claims. (I3, Detailed Description of the Invention Column (1) Page 3, Lines 8 to 14, "The chip ejection groove was constructed."
In contrast to the standard cross-sectional blade shape in which the heel surface and the back surface of the blade that make up the chip ejection groove form a roughly smooth curved surface in the axial cross-section of the drill, there is an approximately U-shape located closer to the center of the heel surface than the heel surface of the standard cross-sectional blade shape. A predetermined range along the axial direction in which the axial length dimension from the contact point between the minor groove and the cutting edge is 0.5 to 1.1 times the drill diameter. It is configured so that it is contained within. ” I am corrected. (2) Insert the following sentence after page 13, line 13. ``Experimental example'' The lifespan of the drill and drill according to the above example was tested by preparing drills corresponding to the example, each with a total length of 1,491,111 mm.
1 and 109mm, the groove length is llllnm and 49mra,
The minor groove length is 111 mm (formed over the entire iM length) and 9 mm, and the tip core thickness is 1.78 mm and 0.
The main groove core thickness taper is O in the above example. Furthermore, the standard drill and the drill of the embodiment have a minor groove center thickness taper of 1.8/100 and 6/1, respectively.
00, groove width ratio of 1.0:I and 0.9:1, helix angle of 3
3° and 25°, and the tip angles are 118° and 135°. Furthermore, the outer diameter of each drill is 12n+n+, the cutting speed (rotation speed) is 25 m/min, and the feed rate of the drill is 0.22 mm.
/ m1nx cutting material JIS 550C (1-I
B 245~255), and the cutting depth of the drill is 60 m.
m. In other words, the drill was designed to penetrate a work material with a thickness of 60 mm. Further, the drill according to the above embodiment has the minor grooves of 9 mm (0.75D), I 2 mm (I D), 1
Using 5 pieces each of 3 types of 8 mm (1.5D),
The conventional drill has a minor groove of 11mm (0, 2, 5D).
Five pieces were used, and the work material was confirmed using a wet method. The experimental conditions were the conventional standard drill and the results of the experiment.
It is shown in Figure 8. In the 9IIlffl example, the average number of through holes for 5 drills is 158, and in the 12nn+ example, it is 5.
The average number of through holes for the standard drill was 143, the average number of through holes for the five drills in the 18 mm example was 120, and the average number of through holes for the five drills for the conventional drill was 63. (C) Brief description of drawings column (1) Page 14, line 6, "This is an explanatory diagram." has been replaced with "Explanatory diagram. Figure 18 is a diagram showing the results of an experimental example."
I will correct it. (II) Figure 18 will be added to the drawings as shown in the attached sheet. Claims ``(1) Chip ejection) 1 constitutes (6) heel surface (
3b) and the blade back surface (3a) form a roughly smooth curved surface in the axial cross section of the drill. The cross-sectional shape having a substantially U-shaped sub-groove (lie, 5a) on the side is referred to as the sub-tF(lie, 5a).
A drill featuring a cutting blade and a filter. ” -N Shichito

Claims (1)

[Claims] (1) Heel surface (3b) forming chip ejection groove (6)
In contrast to the standard cross-sectional blade shape in which the blade back surface (3a) and the blade back surface (3a) form a roughly smooth curved surface in the axial cross-section of the drill, there is a substantially U-shape on the heel surface center side from the heel surface (11b, 5) of the standard cross-sectional blade shape. A drill characterized in that it has a cross-sectional shape having sub-grooves (11c, 5a) recessed in the shape of a shape within a predetermined range along the axial direction from the tip.