JPH0560715U - Carbide drill - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a carbide drill that can stably and efficiently drill deep holes. [Structure] The core thickness is set to 18 to 35% of the drill diameter, and the groove width ratio of the spiral groove 2 is 0.5 to 2.5 of the drill diameter from the tip of the blade.
Double the length range to 0.4-1.0: 1. The groove width is widened in the rear part. Chips cut out to the full width of the groove at the tip of the blade part weaken the flow output as the distance from the cutting edge 3 increases, but the width of the twist groove is widened midway, so the decrease in flow output is compensated by the decrease in outflow resistance. As a result, chips can be discharged smoothly, thrust increase due to chip clogging disappears, and stable drilling of deep holes can be expected.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a solid type carbide drill used for deep hole machining.

[0002]

[Prior Art]

 As shown in Fig. 2, the conventional solid drill for deep hole machining has a constant lead angle of the helical groove 2 over the entire blade, so the distance that chips travel in the helical groove as the machining depth increases. Becomes longer, and it becomes difficult to discharge chips. In particular, when making a hole in a work made of a material that easily extends long, such as a high-toughness metal, the chips that have been extended without breaking are clogged in the twist groove, which makes machining extremely difficult.

For this reason, generally, a method is adopted in which pick feed and step feed are repeated at appropriate depths, and chips are divided and discharged before they become too long, but this method is time-consuming. Since loss occurs, it is not preferable from the viewpoint of high efficiency processing.

Further, when the groove width on the tip end side of the blade portion is increased to a groove width ratio of about 1: 1 to 1.2: 1, chips are discharged smoothly. However, a drill made of a super-hard material such as a super-hard alloy has low toughness of the material, so that the rigidity of the main body is lowered and the drill is easily broken.

In particular, when chips are cut while supplying oil internally using a drill with an oil hole, the temperature of the chips does not rise so much, and in the case of sticky chips, the curl diameter becomes large and the chips tend to become clogged. In deep hole machining, breakage accidents increase.

[0006]

[Problems to be solved by the device]

 It is an object of the present invention to eliminate the above-mentioned problems and enable deeper holes to be machined with a carbide drill, which is advantageous in terms of high efficiency drilling.

[0007]

Means for Solving the Problems In order to solve the above problems, in the present invention, the core thickness is set to 18 to 35% of the drill diameter, and the groove width ratio is set from the tip of the blade to the drill diameter. 0.4 to 1.0: 1 in the length range of 0.5 to 2.5 times. Further, in the portion beyond the above length range to the rear end of the blade portion, the groove width is widened so as to have a groove width ratio of preferably 0.6 to 1.4: 1 rather than the tip side.

[0008]

[Action]

 Since the groove width widens from the middle of the blade, the interference of chips cut into the groove width at the tip of the blade with the groove is reduced from the middle. Therefore, the regulation of chip outflow due to the spiral groove is relaxed, and the chip discharge performance is greatly improved compared to a drill with a constant groove width.

At the tip of the blade where the speed of chip production is maintained, even if the groove width is narrow, the force that pushes out the chips is strong. Therefore, rather than forcibly widening the groove width, the groove width is made narrower and It is preferable that the decrease in rigidity be suppressed and that the groove surface be effectively worked for curling chips in the width direction and cutting in the longitudinal direction. Further, since the flow output of the chips becomes weaker behind the blade portion where the separation distance from the cutting edge becomes larger, it is preferable to reduce the outflow resistance as much as possible. According to the structure of the present invention, since this desirable discharging form is created, chip clogging is unlikely to occur even if the drilled hole depth is increased. Further, this prevents a sudden increase in thrust in the chips, and it is possible to prevent breakage due to insufficient rigidity caused by widening the groove width behind the blade.

[0010]

【Example】

FIG. 1 shows an embodiment of this invention. In FIG. 1, reference numeral 1 denotes a drill body having a cutting edge 3 at its tip, and two twist grooves 2 are provided on the outer periphery thereof. This drill has a core thickness in the range of 0.18 to 0.35D when the outer diameter is D, and the width of the spiral groove 2 is W from the blade tip to point A, which is about 2D away from the tip. _{1. From} point A to point B, it gradually increases from W ₁ to W ₂ (> W ₁ ), and from the point B to the trailing edge of the blade, it is constant at W ₂ .

Although the drill shown in the drawing does not have an oil hole, an oil hole twisted in the twisting direction of the twist groove is provided inside the main body 1 and the hole is opened to the front flank or the like. If the configuration of this invention is adopted for a drill, a particularly great effect can be expected.

The results of cutting experiments using the drill of the present invention and the conventional drill will be described below.

(Experimental Example 1) A cemented carbide drill with an oil hole having an outer diameter D of 8 mm and an effective blade length of 60 mm was used for both the present invention product and the conventional product. The groove width ratio of the conventional drill is 0 from the tip of the blade to the rear of the blade. It is constant at 6: 1. On the other hand, the drill of the present invention has a groove width ratio of 0.6: 1 in the length range of 1.5D from the tip of the blade and 0.9: 1 on the remaining rear side.

The work material is S50C H _B 250, the cutting conditions are speed V = 120 m / min, feed f = 0.2 mm / rev, and cutting depth d = 40 mm. Both drills are water-soluble Cutting was performed while supplying oil from the oil hole to the cutting part. The result is shown in FIG.

(Experimental Example 2) A cemented carbide drill without an oil hole and having a D = 10 mm and an effective blade length of 130 mm was used for both the present invention product and the conventional product. The groove width ratio of the conventional drill is 0.8: 1 in the entire area of the blade portion, and in the drill of the present invention, the length range of 1.5D from the blade tip is 0.8: 1 and the remaining portion is 1.2 :. It is 1.

The work material was F25C, the cutting conditions were V = 100 m / min, f = 0.38 mm / rev, and d = 100 mm, and cutting was performed while water-soluble cutting oil was externally supplied. The result is shown in FIG.

As can be seen from the results of these two experiments, in the conventional drill, the thrust increases sharply as the hole depth increases, and in some cases breakage occurs, but the drill of the present invention has a small increase in thrust. Stable drilling of deep holes.

[0018]

[Effect of the device]

 As described above, in the drill of this invention, the width of the twist groove is widened on the rear side of the blade where the flow output of chips is weakened to improve the chip discharge performance. The increase is prevented and it becomes possible to machine deeper holes stably and with high efficiency.

[Brief description of drawings]

1 is an example of a drill of the present invention, (a) is a front view, (b) is an enlarged cross-sectional view of the XX line part of (a),
(C) is an enlarged sectional view of the YY line part of (a).

FIG. 2 is a view showing a conventional drill, (a) is a front view,
(B) is an enlarged sectional view of the XX line portion of (a), and (c) is an enlarged sectional view of the YY line portion of (a).

[Figure 3] Comparison of cutting experiment results

[Fig. 4] Comparison of cutting test results

[Explanation of symbols]

 1 Drill body 2 Helical groove 3 Cutting edge

Claims (3)

[Scope of utility model registration request] 1. The core thickness is in the range of 18 to 35% of the drill diameter, and the groove width ratio is 0.5 to 2.5 of the drill diameter from the tip of the blade.
Carbide drill with a double length range of 0.4 to 1.0: 1, and a groove width that is wider than the tip side in the part beyond the above length range to the rear end of the blade part .. 2. The groove width ratio of the portion reaching the rear end of the blade portion is 0.
The cemented carbide drill according to claim 1, which is set to 6 to 1.4: 1. 3. The cemented carbide drill according to claim 1, wherein an oil hole twisted in a twist direction of the twist groove is provided inside the main body.