JP2002036016A - Stepped boring tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepped boring tool capable of stably cutting a stepped hole having high hole machining accuracy and a finished surface for a long time. SOLUTION: This stepped boring tool comprises at least two continuous main discharge grooves 13 formed from a small diameter part 11 on the tip side of a tool body 10 to a large diameter part 12 on the base end side, outer peripheral edges 11a and 12a on the outer peripheries of the small diameter part and the large diameter part in the rotation direction after each main discharge groove, and respective margins 11b, 11c, 12b, and 12c provided rotation directionally before and after the main discharge grooves 13 in the small diameter part and the large diameter part. Sub discharge grooves 14 with acute groove angle θ are continuously provided from the small diameter part and the large diameter part in the rotation direction before the margins 11b and 12b in the rotation direction before the main discharge grooves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepped drilling tool used for forming a stepped hole having a small diameter hole and a large diameter hole in a work material, and more particularly to a tip of a tool body. At least two continuous main discharge grooves are provided from the small-diameter portion on the side to the large-diameter portion on the base end side, and an outer peripheral edge is formed on the outer periphery of the small-diameter portion and the large-diameter portion rearward in the rotation direction with respect to the main discharge groove. In addition, in the small diameter portion and the large diameter portion,
In the stepped drilling tool in which a margin is provided on the front and rear sides in the rotation direction with respect to the main discharge groove, a margin on the front side in the rotation direction with respect to the main discharge groove so as not to reduce the rigidity in the large diameter portion. This is characterized in that chips are prevented from being clogged and welded at the portion, and that a stepped hole with good hole processing accuracy and finished surface accuracy can be stably processed.

[0002]

2. Description of the Related Art Conventionally, a stepped drilling tool has been used to form a stepped hole having a small diameter hole and a large diameter hole in a work material.

Here, as shown in FIGS. 1A and 1B, such a stepped drilling tool generally has a small diameter at the tip end side of a tool body 10 having a cutting edge 15 formed at the tip end. Two main discharge grooves 13 are provided continuously from the portion 11 to the large-diameter portion 12 on the base end side, and an outer peripheral edge is provided on the outer periphery of the small-diameter portion 11 and the large-diameter portion 12 with respect to the two main discharge grooves 13 at the rear in the rotation direction. 11a, 12a are formed, and margins 11b, 11c, 12b, 12c are provided in the small-diameter portion 11 and the large-diameter portion 12, respectively, in front of and behind the main discharge groove 13 in the rotational direction of the tool body 1. Further, the one having a chamfering blade 16 provided between the outer peripheral edge 11a of the small diameter portion 11 and the outer peripheral edge 12a of the large diameter portion 12 has been used.

When a stepped hole having a small diameter hole and a large diameter hole is provided in a work material using such a stepped drilling tool, the above-mentioned cutting edge 15 and chamfering blade 16 are used. The chips that have been cut are discharged through the main discharge groove 13.

[0005] However, in the stepped drilling tool as described above, a part of the chips cut as described above is generated between the margins 11b and 11c in the small diameter portion 11 and the large diameter portion 12, and between the margin 12b and the margin 12b. The chips enter the outer periphery second-recessed portion between the small-diameter portion 11c and the margin 12c.
And the large diameter portion 12 is welded to the margins 11b and 12b on the rotation direction front side with respect to the main discharge groove 13, respectively, so that the machining accuracy of the small diameter hole and the large diameter hole is reduced and the surface roughness of these holes is reduced. There was a problem of lowering.

In order to prevent chips from welding to the margins 11b and 12b in the small-diameter portion 11 and the large-diameter portion 12 on the rotationally forward side of the main discharge groove 13 as shown in FIG. As shown in FIGS. 1A to 1C, a sub-discharge groove 14 is provided continuously from the small-diameter portion 11 to the large-diameter portion 12 on the rotation direction front side of the margins 11b and 12b. It is conceivable to discharge the chips that have entered the outer peripheral second-order portion between the margin 11b and the margin 11c and between the margin 12b and the margin 12c.

Here, in providing the sub-discharge grooves 14 as described above, a groove angle of about 90 ° was obtained by using a groove grinding wheel having a wheel angle of 90 ° which has been generally used conventionally. When the sub-discharge groove 14 is provided continuously from the small diameter portion 11 to the large diameter portion 12, as shown in FIG.
The auxiliary discharge groove 14 reduces the back metal on the rear side in the rotation direction from the outer peripheral edge 12a of the large-diameter portion 12 and lowers rigidity, so that the chamfering blade 16 and the outer peripheral edge 12a of the large-diameter portion 12 are liable to be damaged. A problem that stable cutting cannot be performed over a wide range.

[0008]

SUMMARY OF THE INVENTION The present invention relates to various problems described above in a step drilling tool used for providing a stepped hole having a small diameter hole and a large diameter hole in a work material. It is an object to solve the above.

That is, according to the present invention, at least two main discharge grooves are provided continuously from the small diameter portion on the distal end side of the tool body to the large diameter portion on the base end side, and the main discharge groove is provided rearward in the rotational direction with respect to the main discharge groove. An outer peripheral edge is formed on the outer periphery of the small-diameter portion and the large-diameter portion, and a stepped hole is formed in the small-diameter portion and the large-diameter portion, with a margin provided forward and rearward in the rotational direction with respect to the main discharge groove. In the drilling tool, in order to prevent chips from clogging and welding in a margin portion on the rotation direction front side from the main discharge groove, when a sub-discharge groove is provided on the rotation direction front side from this margin, the large diameter portion To reduce the amount of back metal in the hole, to prevent damage to the chamfering blade and the outer peripheral edge in the large-diameter portion, and to provide a stepped hole with good hole machining accuracy and finished surface accuracy for a long time. It is an object to make it possible to stably cut me.

[0010]

According to the present invention, in order to solve the above-mentioned problems, a main discharge groove continuous from a small-diameter portion 11 on the distal end side of the tool body 10 to a large-diameter portion 12 on the proximal end side is provided. At least two outer peripheral edges 11a, 12a are formed on the outer periphery of the small-diameter portion 11 and the large-diameter portion 12 at the rear of the main discharge groove 13 in the rotation direction. A stepped drilling tool in which margins 11b, 11c, 12b, and 12c are provided in the radial portion 12 in the rotational direction front and rear with respect to the main discharge groove 13, respectively. Margin 11 in front of rotation direction
The auxiliary discharge groove 14 having the acute groove angle θ is provided continuously from the small-diameter portion 11 to the large-diameter portion 12 on the front side in the rotation direction from b and 12b.

Further, like the stepped drilling tool of the present invention, the sub-discharge groove 14 is extended from the small-diameter portion 11 to the rotationally forward side of the margins 11b and 12b in the rotational direction forward with respect to the main discharge groove 13. When the chip is provided continuously to the diameter portion 12, a part of the chips is located between the margin 11 b and the margin 11 c in the small diameter portion 11 and the large diameter portion 12,
Even if the chips enter the outer periphery second-recessed portion between the b and the margin 12c, the chips are discharged through the sub-discharge groove 14 and the main discharge groove 13 in the small-diameter portion 11 and the large-diameter portion 12. Margin 11 in front of rotation direction
The welding of chips to the portions b and 12b is suppressed.

When the groove angle θ of the sub-discharge groove 14 is made acute, as in the stepped drilling tool of the present invention, the sub-discharge is continuously performed from the small diameter portion 11 to the large diameter portion 12 as described above. Even if the groove 14 is provided, the size of the sub-discharge groove 14 in the large-diameter portion 12 is reduced, and the reduction of the back metal on the large-diameter portion 12 on the rear side in the rotation direction from the outer peripheral edge 12a is suppressed. 12 can be prevented from being damaged.

Therefore, when a stepped hole having a small diameter hole and a large diameter hole is formed by using the stepped drilling tool according to the present invention, the main discharge grooves in the small diameter portion 11 and the large diameter portion 12 are formed. Margin 11 in the rotation direction ahead of 13
The welding of chips to the portions b and 12b is suppressed, and the outer peripheral edge 12a of the large-diameter portion 12 is prevented from being damaged. To be able to cut.

When the sub-discharge groove 14 having the acute groove angle θ as described above is continuously provided from the small-diameter portion 11 to the large-diameter portion 12, the groove angle θ in the sub-discharge groove 14 is set.
When the diameter of the auxiliary discharge groove 14 is increased or the depth of the auxiliary discharge groove 14 is increased, the amount of the back metal on the rear side in the rotation direction from the outer peripheral edge 12a of the large diameter portion 12 is reduced, and the rigidity is reduced. The groove angle θ in the discharge groove 14
Is too small or the depth of the sub-discharge groove 14 is too shallow, chips will not be sufficiently discharged through the sub-discharge groove 14, and chips will not be discharged.
12b, the groove angle θ of the sub-discharge groove 14 is set in the range of 15 ° to 50 °.
The groove depth t in the small diameter portion 11 of FIG.
It is preferable to be within the range.

In the stepped drilling tool according to the present invention, the sub-discharge groove 14 having the acute groove angle θ as described above may be provided continuously from the small-diameter portion 12 to the large-diameter portion 13. In order to further increase the length of the sub-discharge groove 14 in the large-diameter portion 13, after cutting the above-mentioned sub-discharge groove 14 in which the groove angle θ is acute,
It is also possible to provide a second sub-discharge groove having a shallower groove depth so as to be continuous with the sub-discharge groove 14 in the middle of the cut-up portion 4. In the second sub-discharge groove, the groove angle does not necessarily need to be acute.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A stepped drilling tool according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

In the stepped drilling tool according to this embodiment, as shown in FIGS. 3A to 3C, the small diameter portion 11 on the tip end side of the tool body 10 having the cutting edge 15 formed at the tip end. Main discharge groove 13 continuous with large diameter portion 12 on the end side
Are provided.

Outer edges 11a and 12a are formed on the outer periphery of the small-diameter portion 11 and the large-diameter portion 12 at the rear side in the rotation direction with respect to the two main discharge grooves 13, respectively. The margins 11b, 11c, 12b, and 1 are provided at the small diameter portion 11 and the large diameter portion 12 at the front and rear in the rotation direction of the tool body 10, respectively.
2c is provided, and a chamfer blade 16 is provided between the outer peripheral edge 11a of the small diameter portion 11 and the outer peripheral edge 12a of the large diameter portion 12.

In the stepped drilling tool according to this embodiment, the large-diameter portion 11 is located at a position forward of the margins 11b, 12b in the rotational direction forward with respect to the main discharge groove 13 from the small-diameter portion 11. A sub-discharge groove 14 having an acute groove angle θ is provided continuously with the radial portion 12.

Here, the sub-discharge groove 14 in which the groove angle θ becomes acute from the small diameter portion 11 to the large diameter portion 12 as described above.
In this embodiment, the groove diameter of the small-diameter portion 11 is adjusted by using a groove grinding wheel having an acute wheel angle.
Groove cutting is performed from the tip of the above, from the part slightly entering the large diameter part 12 beyond the inclined part between the small diameter part 11 and the large diameter part 12, the groove cutting by the groove grinding wheel is rounded up,
A sub-discharge groove 14 having an acute groove angle θ is provided continuously from the small diameter portion 11 to the large diameter portion 12.

In this embodiment, the sub-discharge groove 14 having the acute groove angle θ as described above is provided continuously from the small-diameter portion 11 to the large-diameter portion 12, and then rounded up as described above. From the middle of the sub-discharge groove 14
To the second sub-discharge groove 1 having a shallow groove depth.
4a is provided. In addition, as described above, the second auxiliary discharge groove 1
In providing 4a, the groove angle is set to about 90 °.

In the case where the stepped hole drilling tool of this embodiment is used to form a stepped hole in which a small diameter hole and a large diameter hole are continuous in a work material, the above-described cutting edge 15 at the tip end is used.
Chips cut by the chamfering blade 16 between the small diameter portion 11 and the large diameter portion 12 are discharged through the main discharge groove 13. Chips that have entered between the margin 11b and the margin 11c and between the margin 12b and the margin 12c in the small-diameter portion 11 and the large-diameter portion 12 enter the outer discharge second portion and the second discharge groove 14 and the second Sub-drain 1
4a, and a margin 1 in the rotation direction ahead of the main discharge groove 13 in the small diameter portion 11 or the large diameter portion 12.
The welding of chips to the portions 1b and 12b is suppressed, and a stepped hole with good hole machining accuracy and finished surface accuracy can be obtained. Further, since the groove angle θ of the sub-discharge groove 14 is an acute angle, a large amount of back metal remains on the rear side in the rotation direction from the outer peripheral edge 12 a of the large-diameter portion 12, and the large-diameter portion 12 has The outer peripheral edge 12a is prevented from being damaged, and a good stepped hole can be stably cut over a long period of time.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, when a stepped hole in which a small-diameter hole and a large-diameter hole are successively provided in a work material using a stepped drilling tool according to an embodiment of the present invention will be described for a long time. It will be clarified that a stepped hole with good hole processing accuracy and finished surface accuracy can be obtained by using a comparative example.

(Embodiment) In the stepped drilling tool according to this embodiment, the diameter of the small diameter portion 11 in the tool body 10 is 5 in the stepped drilling tool shown in FIGS. 0.6 mm, the length of the small-diameter portion 11 was 17 mm, and the diameter of the large-diameter portion 12 was 8 mm. A cutting blade 15 was provided at the tip of the small-diameter portion 11, and the small-diameter portion 11 was moved to the large-diameter portion 1.
2, two main discharge grooves 13 were provided.

Then, at a position on the rotationally forward side of the margins 11b and 12b on the forward side in the rotational direction with respect to each main discharge groove 13, the groove angle θ from the small diameter portion 11 to the large diameter portion 12 becomes an acute angle. In providing the changed auxiliary discharge groove 14,
A groove grinding wheel having a diameter of 30 mm and a wheel angle of 35 ° was used. The groove angle θ was 35 °, the groove depth t in the small diameter portion 11 was 0.5 mm, and the groove depth in the large diameter portion 11 was 1.
7 mm, the bottom of the groove is formed in an arc shape having a radius of 0.3 mm, and a portion that slightly enters the large diameter portion 12 from the tip of the small diameter portion 11 beyond the inclined portion between the small diameter portion 11 and the large diameter portion 12. The groove cutting by the above-mentioned groove grinding wheel was rounded up. Thereafter, the large-diameter portion 12 has a groove depth of 0.5 mm and a groove angle of 90 ° so as to be continuous with the sub-discharge groove 14 from the middle of the sub-discharge groove 14 thus cut up. The second sub-discharge groove 14a was provided to an appropriate position.

(Comparative Example 1) In the stepped drilling tool of Comparative Example 1, as shown in FIGS.
The sub-discharge groove 14 was not provided, and the rest was the same as the stepped drilling tool of the above embodiment.

(Comparative Example 2) In the stepped drilling tool of Comparative Example 2, when the sub-discharge groove 14 continuous from the small diameter portion 11 to the large diameter portion 12 was provided, the diameter was 100 mm and the wheel angle was 90 °. Fig. 2 using a groove grinding wheel
As shown in (A) to (C), the groove angle θ is 90 °, the groove depth in the small diameter portion 11 is 0.5 mm, the groove depth in the large diameter portion 11 is 1.7 mm, and the radius at the groove bottom is 0.1 mm. A large-diameter portion 12 from the tip of the small-diameter portion
The sub-discharge groove was formed by forming a groove to an appropriate position, and the other conditions were the same as those of the stepped drilling tool of the above embodiment.

Then, using the stepped drilling tools of the above Examples and Comparative Examples 1 and 2, the rotation speed was 10,000 rpm and the feed rate was 0.15 mm with respect to the aluminum work material.
Under a cutting condition of / rev, a hole having a depth of 20 mm was formed by using a water-soluble coolant to form a stepped hole in which a small diameter hole and a large diameter hole were continuous.

As a result, when the stepped hole drilling tool of the above embodiment is used, the enlargement margin of the small diameter hole at the time of machining the 10000 stepped hole is 2 μm or less, and the surface roughness R
z was 2 μm or less, and a stepped hole with good hole processing accuracy and finished surface accuracy was obtained.

On the other hand, in the stepped drilling tool of Comparative Example 1 in which the sub-drainage groove was not provided, the allowance for the small diameter hole at the time of machining the 10,000 stepped holes was 35 μm and the surface roughness was large. Rz was 10 μm, and the hole machining accuracy and the finished surface accuracy were much worse than when the stepped drilling tool of the example was used.

In the stepped drilling tool of Comparative Example 2 provided with the sub-discharge groove 14 having the groove angle θ of 90 °,
At the time when about 5,000 stepped holes were machined, the chamfer blade 16 and the outer peripheral edge 12a of the large-diameter portion 12 near the chamfer blade 16 were damaged.

[0032]

As described in detail above, in the stepped drilling tool according to the present invention, each of the main discharge grooves provided continuously from the small diameter portion on the distal end side to the large diameter portion on the proximal end side of the tool body. On the other hand, since the auxiliary discharge groove having an acute angle of the groove angle θ is provided continuously from the small-diameter portion to the large-diameter portion on the rotation-direction front side of the margin in the rotation-direction front portion, some of the chips are reduced in the small-diameter portion. Even if the chips enter the portion between the margins in the large diameter portion, the chips are discharged through the sub-discharge groove, and the chips are deposited on the margin portion in the rotational direction ahead of the main discharge groove in the small diameter portion and the large diameter portion. In addition to being suppressed, the back metal on the rear side in the rotational direction from the outer peripheral edge of the large diameter portion is not greatly reduced, and the outer peripheral edge or the like of the large diameter portion is also prevented from being damaged. It was.

As a result, when a stepped hole having a small diameter hole and a large diameter hole is formed by using the stepped hole drilling tool of the present invention, the stepped hole having good hole machining accuracy and finished surface accuracy. Can be stably cut over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic side view and a schematic front view of a conventional stepped drilling tool having no auxiliary discharge groove.

FIG. 2 is a schematic side view, a schematic front view, and a cross-sectional explanatory view of a large-diameter portion of a conventional stepped drilling tool provided with a sub-discharge groove having a groove angle of 90 °.

FIG. 3 is a schematic side view of a stepped drilling tool according to an embodiment of the present invention provided with an auxiliary discharge groove having an acute groove angle;
It is a schematic front view and sectional explanatory drawing of a large diameter part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Tool main body 11 Small diameter part 11a Outer edge of small diameter part 11b, 11c Margin of small diameter part 12 Large diameter part 12a Outer edge of large diameter part 12b, 12c Margin of large diameter part 13 Main discharge groove 14 Secondary discharge groove 15 Tip cut Blade 16 Chamfering blade θ Groove angle t Groove depth of sub-discharge groove in small diameter part

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Kyoichi Matsumoto, Inventor 2-1-1-18 Kamihigashi, Hirano-ku, Osaka Dai-Jet Industrial Co., Ltd. F-term (reference) 3C037 AA08 DD01 DD03

Claims (3)

[Claims] 1. A small-diameter portion 1 on a tip side of a tool body 10.
At least two main discharge grooves 13 are provided continuously from 1 to the large-diameter portion 12 on the base end side. The edges 11a and 12a are formed, and the small-diameter portion 11 and the large-diameter portion 12 form the main discharge groove 1 described above.
Margin 1 forward and backward in the rotation direction for 3
In the stepped drilling tool provided with 1b, 11c, 12b, and 12c, the groove angle θ becomes an acute angle forward of the margins 11b and 12b in the rotational direction with respect to the main discharge groove 13 with respect to the main discharge groove 13. A stepped drilling tool characterized in that the sub-discharge groove 14 is provided continuously from the small diameter portion 11 to the large diameter portion 12. 2. The stepped drilling tool according to claim 1, wherein a groove angle θ of the auxiliary discharge groove 14 is 15 °.
A stepped drilling tool characterized by a range of up to 50 °. 3. The stepped drilling tool according to claim 1, wherein the sub-discharge groove (14) in the small diameter portion (12).
Characterized in that the groove depth t is in the range of 0.3 to 1.0 mm.