JP2022061800A - Boring drill - Google Patents

Abstract

To provide a boring drill capable of reducing noise when cutting a workpiece by the boring drill.SOLUTION: A boring drill 10 comprises: a first blade 21 and a second blade 22 on a first end 11; a first spiral stop part 41 and a second spiral stop part 42 extending from the first blade 21/second blade 22 to a second end 12; and a first spiral helical gash 31 and a second spiral helical gash 32 which are provided between the first stop part 41 and the second stop part 42 adjacent in a rotary direction C, and extends along the first stop part 41 and the second stop part 42. The first stop part 41 extends at a first helix angle and the second stop part 42 has at least, parts which extend at an intermediate helix angle β and at a base end helix angle, respectively.SELECTED DRAWING: Figure 3

Description

The present invention relates to a drilling drill.

Conventionally, a drilling drill as described in Patent Document 1 is known.
The above-mentioned drilling drill has a plurality of blades, a plurality of spiral abutments extending from each of the a plurality of blades, and a plurality of spiral twisted grooves provided between the a plurality of abutments and extending along the abutment. It has.

Japanese Patent No. 4484716

However, there is a risk that noise will be generated when cutting the work with a drill.

The drilling drill that solves the above problems is a drilling drill that rotates around an axis.
A plurality of blades provided at the first end in the axial direction, a plurality of spiral abutments extending from each of the plurality of blades toward the second end in the axial direction, and adjacent portions in the rotation direction about the axis. A spiral twisted groove provided between the mating portions and extending along the abutment portion is provided, and the plurality of the abutment portions are the first abutment portion extending at the first helix angle. , The second hit portion, which is the hit portion having at least a portion extending at the second twist angle, which is a twist angle different from the first twist angle.

According to this, at the same depth of the hole of the work, the portion where the first contact portion is in contact with the inner peripheral surface of the hole and the portion where the second contact portion is in contact with the inner peripheral surface of the hole are formed. When compared in the radial direction of the drill, the contact point where the first contact portion is in contact with the inner peripheral surface of the hole and the contact point where the second contact portion is in contact with the inner peripheral surface of the hole are There are some points that do not match in the radial direction and are offset in the axial direction. Each of the plurality of abutments extends at the first helix angle, and at the same depth of the hole, the first abutment abuts on the inner peripheral surface of the hole and the second abutment abuts on the inner peripheral surface of the hole. Unlike the case where the contacting portion coincides in the radial direction and the axial direction, the resonance of sound can be suppressed. Therefore, it is possible to reduce noise when cutting a work with a drill.

In the drilling drill, the second contact portion is the tip end side spiral portion extending from the blade at the first twist angle and the tip end at an intermediate twist angle which is the second twist angle larger than the first twist angle. It is preferable to have an intermediate spiral portion extending from the side spiral portion and a proximal side spiral portion extending from the intermediate spiral portion at a proximal twist angle which is the second twist angle smaller than the intermediate torsion angle.

If the second contact portion continues to extend at the intermediate helix angle, the second contact portion intersects the first contact portion due to the design of the drilling drill.
In that respect, according to this, a proximal end side spiral portion extending from the intermediate spiral portion at the proximal end helix angle is provided. Therefore, it becomes difficult for the extended end of the second hit portion to intersect with the first hit portion. Therefore, in the design of the drilling drill, the function of the drilling drill as a drill can be maintained.

According to the present invention, noise when cutting a work can be reduced.

Schematic view of the spiral portion on the tip side of the drill drill as seen from the front. The schematic which showed the cutting edge of the drilling drill. Schematic view of the boundary between the tip side spiral part and the intermediate spiral part of the drill drill as seen from the front. Schematic diagram of the boundary between the intermediate spiral portion of the drill and the helical portion on the proximal end side as viewed from the front. The schematic diagram which showed the situation at the time of cutting a work by a drill. The schematic diagram which showed the situation at the time of cutting a work by a drill.

Hereinafter, an embodiment in which the drilling drill is embodied will be described with reference to FIGS. 1 to 6.
As shown in FIGS. 1 and 2, the drilling drill 10 is formed by processing one round bar. Assuming that the axis of the drill 10 is m, the direction in which the axis m extends is the axis direction A of the drill 10. The direction orthogonal to the axis m of the drilling drill 10 is defined as the radial direction B. The direction in which the drill 10 rotates about the axis m is defined as the rotation direction C.

As shown in FIG. 2, the drill 10 has a first blade 21 provided at the first end 11 in the axial direction A and a second blade 22 provided at the first end 11. The first blade 21 and the second blade 22 are arranged at positions symmetrical with each other in the radial direction B with respect to the axis m of the drilling drill 10. The first blade 21 and the second blade 22 are a plurality of blades provided at the first end 11 of the axial direction A of the drilling drill 10 in the rotation direction C at predetermined intervals.

As shown in FIGS. 1 and 4, the rake angles θ1 of the first blade 21 and the second blade 22 are the same as each other. The rake angle θ1 is, for example, the angle formed by the first blade 21 and the axis m when the portion of the cutting edge 21a of the first blade 21 located on the outermost side of the radial direction B in the radial direction B is viewed from the front. Is. Further, the rake angle θ1 is, for example, the second blade 22 and the axis m when the portion of the cutting edge 22a of the second blade 22 located on the outermost side of the radial direction B in the radial direction B is viewed from the front. The angle to make.

As shown in FIGS. 1, 3, and 4, the drilling drill 10 includes a first twisted groove 31 and a second twisted groove 32. The first twisted groove 31 and the second twisted groove 32 are spiral grooves provided on the outer peripheral surface of one round bar.

The first twisted groove 31 extends spirally from the first end 11 of the drill 10 toward the second end 12 in the axial direction A about the axis m. The first twisted groove 31 extends from the first end 11 toward the second end 12 so as to go in the direction opposite to the rotation direction C. The first twisted groove 31 extends spirally from a position adjacent to the first blade 21 in the rotation direction C toward the second end 12. The second twisted groove 32 extends spirally from the first end 11 of the drilling drill 10 toward the second end 12 about the axis m. The second twisted groove 32 extends from the first end 11 of the drilling drill 10 toward the second end 12 in the direction opposite to the rotation direction C. The second twisted groove 32 extends spirally from a position adjacent to the second blade 22 in the rotation direction C toward the second end 12. The first twisted groove 31 and the second twisted groove 32 are provided so as not to overlap each other in the rotation direction C. The first twisted groove 31 and the second twisted groove 32 do not extend to the second end 12. The inner surface of the first twisted groove 31 includes the surface of the first blade 21 forming a rake angle θ1. The inner surface of the second twisted groove 32 includes the surface of the second blade 22 forming the rake angle θ1.

The drilling drill 10 includes a first per portion 41 and a second per portion 42. The first contact portion 41 and the second contact portion 42 are formed by providing the first twist groove 31 and the second twist groove 32 in the drilling drill 10.

The first per portion 41 is continuous with the first blade 21. The first contact portion 41 extends spirally from the first blade 21 toward the second end 12 of the drilling drill 10 about the axis m. The first contact portion 41 is arranged between the first twist groove 31 and the second twist groove 32 adjacent to each other in the rotation direction C.

The second contact portion 42 extends spirally from the second blade 22 toward the second end 12 of the drilling drill 10 about the axis m. Each of the first contact portion 41 and the second contact portion 42 extends spirally from the first end 11 to the second end 12 of the drilling drill 10 in the direction opposite to the rotation direction C.

The first per portion 41 and the second per portion 42 are provided so as not to overlap each other in the rotation direction C. The first contact portion 41 is a spiral contact portion extending from the first blade 21 toward the second end 12. The second contact portion 42 is a spiral contact portion extending from the second blade 22 toward the second end 12. The first twisted groove 31 and the second twisted groove 32 are provided between the first hit portion 41 and the second hit portion 42 adjacent to each other in the rotation direction C, and the first hit portion 41 and the second hit portion 42 are provided. It is a spiral twisted groove extending along 42.

In the drilling drill 10 configured in this way, the portion on the second end 12 side where the first twisted groove 31, the second twisted groove 32, the first per portion 41, and the second per portion 42 are not provided is not shown. Attached to power tools. The drilling drill 10 is rotated in the rotation direction C by an electric tool (not shown).

As shown in FIGS. 5 and 6, the drilling drill 10 is brought into contact with the work W in the axial direction A while rotating in the rotation direction C. When the first blade 21 and the second blade 22 come into contact with the work W, the work W is cut and a hole H is formed in the work W. When the work W is cut by the drill 10, the first contact portion 41 and the second contact portion 42 come into contact with the inner peripheral surface Ic of the hole H of the work W. The first contact portion 41 and the second contact portion 42 come into surface contact with the inner peripheral surface Ic of the hole H of the work W. Since the first contact portion 41 and the second contact portion 42 abut on the inner peripheral surface Ic of the hole H, the displacement of the drill 10 in the radial direction B is suppressed. Further, the first per portion 41 and the second per portion 42 guide the cutting direction of the rotating drill 10 in one direction. Therefore, the cutting work of the drill 10 is stable.

The chips of the work W cut by the first blade 21 and the second blade 22 enter the first twist groove 31 and the second twist groove 32. Chips that have entered the first twisted groove 31 and the second twisted groove 32 are drilled by the inner surfaces of the first twisted groove 31 and the second twisted groove 32 when the drilling drill 10 is rotating in the rotation direction C. It is guided toward the second end 12 of. Therefore, the chips when the work W is cut by the drill 10 are discharged to the outside of the work W without staying at the cutting portion of the work W.

Next, the configuration of the first per unit 41 and the second per unit 42 will be described in detail. Hereinafter, a helix angle having the same magnitude as the rake angle θ1 of each of the first blade 21 and the second blade 22 will be described as the first helix angle α. The helix angle is a virtual direction in which the first per portion 41 and the second per portion 42 extend spirally when the first per portion 41 and the second per portion 42 are viewed from the front in the radial direction B. It is an angle formed by the virtual line L1 existing in the above and the axis m of the drilling drill 10.

As shown in FIGS. 1, 3, and 4, the first per portion 41 is a per portion that extends at the first helix angle α from the first end 11 to the second end 12 of the drilling drill 10.
The helix angle of the second contact portion 42 changes twice from the first end 11 to the second end 12 of the drilling drill 10. That is, when the dihedral portion 42 is viewed from the front in the radial direction B, the helix angle changes when the drilling drill 10 is rotated in the rotation direction C by a predetermined angle in the order of FIGS. 1, 3, and 4. The second contact portion 42 has a tip end side spiral portion 421, an intermediate spiral portion 422, and a proximal end side spiral portion 423.

As shown in FIG. 1, the tip-side spiral portion 421 spirally extends from the second blade 22 toward the second end 12 in the direction opposite to the rotation direction C. The tip-side spiral portion 421 extends from the second blade 22 in the direction opposite to the rotation direction C at the first helix angle α. The tip-side spiral portion 421 is a portion of the second per portion 42 that extends from the second blade 22 in a direction opposite to the rotation direction C by a predetermined angle.

As shown in FIG. 3, the intermediate spiral portion 422 extends continuously with the distal end side spiral portion 421. The intermediate spiral portion 422 extends spirally toward the second end 12 so as to go in the direction opposite to the rotation direction C. The intermediate spiral portion 422 extends from the tip of the distal end side spiral portion 421 extending from the second blade 22 at an intermediate helix angle β. The intermediate helix angle β is the helix angle of the intermediate spiral portion 422. The intermediate helix angle β is larger than the first helix angle α. The intermediate spiral portion 422 is a portion of the second peripheral portion 42 that extends from the extended end of the distal end side spiral portion 421 in a direction opposite to the rotation direction C by a predetermined angle. The boundary between the tip side spiral portion 421 and the intermediate spiral portion 422 is defined as Bd1. When the boundary Bd1 is viewed from the front in the radial direction B, the boundary Bd1 is along the axis m of the drilling drill 10.

As shown in FIG. 4, the proximal end side spiral portion 423 extends continuously with the intermediate spiral portion 422. The base end side spiral portion 423 extends spirally toward the second end 12 so as to go in the direction opposite to the rotation direction C. The proximal end side spiral portion 423 extends from the tip of the intermediate spiral portion 422 extending from the distal end side spiral portion 421 at the proximal end helix angle γ. The base end twist angle γ is the twist angle of the base end side spiral portion 423. The base end helix angle γ is smaller than the first helix angle α. The base end helix angle γ is smaller than the intermediate helix angle β. The base end side spiral portion 423 is a portion of the second peripheral portion 42 that extends from the extended end of the intermediate spiral portion 422 in the direction opposite to the rotation direction C by a predetermined angle. The boundary between the intermediate spiral portion 422 and the proximal end side spiral portion 423 is defined as Bd2. When the boundary Bd2 is viewed from the front in the radial direction B, the boundary Bd2 is along the axis m of the drilling drill 10.

The second contact portion 42 has a spiral shape due to the distal end side spiral portion 421, the intermediate spiral portion 422, and the proximal end side spiral portion 423 extending continuously in the direction opposite to the rotation direction C. The intermediate helix angle β and the proximal twist angle γ are second helix angles different from the first helix angle α. Further, the intermediate helix angle β is a second helix angle larger than the first helix angle α, and the proximal twist angle γ is a second helix angle smaller than the intermediate helix angle β.

The operation of this embodiment will be described. For convenience of explanation, the drill 10 in FIGS. 5 and 6 is a front view seen from the radial direction B, and the work W is a cross-sectional view.
As shown in FIG. 5, a hole H is formed in the work W by cutting the work W with the drilling drill 10.

The first contact portion 41 extends from the first blade 21 toward the second end 12 of the drill 10 at the first helix angle α, and the tip-side spiral portion 421 is drilled from the second blade 22 at the first helix angle α. It extends toward the second end 12 of the drill 10. Therefore, at the same depth of the hole H, the portion where the tip-side spiral portion 421 abuts on the inner peripheral surface Ic of the hole H and the portion where the first contact portion 41 abuts on the inner peripheral surface Ic of the hole H have diameters. Match in direction B. Further, the portion where the tip-side spiral portion 421 abuts on the inner peripheral surface Ic of the hole H and the portion where the first contact portion 41 abuts on the inner peripheral surface Ic of the hole H coincide with each other in the axial direction A.

The first contact point is the contact point located closer to the first end 11 of the portions where the first contact portion 41 located on the opposite side of the intermediate spiral portion 422 in the radial direction B is in contact with the inner peripheral surface Ic of the hole H. Let P1 be, and let the contact point located closer to the second end 12 be the second contact point P2. Of the portions where the intermediate spiral portion 422 is in contact with the inner peripheral surface Ic of the hole H, the contact point located closer to the first end 11 is defined as the third contact point P3, and the contact point located closer to the second end 12 is designated as the third contact point. 4 The contact point P4. In the present embodiment, the third contact point P3 is located closer to the first end 11 than the first contact point P1 in the axial direction A. That is, in the radial direction B, the first contact portion 41 is not located at the position corresponding to the third contact point P3 of the intermediate spiral portion 422. Further, in the present embodiment, in the axial direction A, the fourth contact point P4 is located closer to the first end 11 than the second contact point P2. That is, in the radial direction B, the intermediate spiral portion 422 is not located at the position corresponding to the second contact point P2 of the first contact portion 41. Therefore, at the same depth of the hole H, a portion where the first contact portion 41 is in contact with the inner peripheral surface Ic of the hole H and a portion where the intermediate spiral portion 422 is in contact with the inner peripheral surface Ic of the hole H. The first contact point 41 is in contact with the inner peripheral surface Ic of the hole H, and the intermediate spiral portion 422 is in contact with the inner peripheral surface Ic of the hole H. There is a point where the contacts do not match in the radial direction B and are displaced in the axial direction A.

As shown in FIG. 6, in the radial direction B, the first contact portion 41 located on the opposite side of the proximal end side spiral portion 423 is closer to the first end 11 of the portions in contact with the inner peripheral surface Ic of the hole H. The located contact point is referred to as the fifth contact point P5, and the contact point located closer to the second end 12 is referred to as the sixth contact point P6. Of the portions where the base end side spiral portion 423 is in contact with the inner peripheral surface Ic of the hole H, the contact point located closer to the first end 11 is set as the seventh contact point P7, and the contact point located closer to the second end 12. Is the eighth contact point P8. In the present embodiment, the seventh contact point P7 is located closer to the first end 11 than the fifth contact point P5 in the axial direction A. That is, in the radial direction B, the first contact portion 41 is not located at the position corresponding to the seventh contact point P7 of the proximal end side spiral portion 423. Further, in the present embodiment, in the axial direction A, the sixth contact point P6 is located closer to the first end 11 than the eighth contact point P8. That is, in the radial direction B, the first per portion 41 is not located at the position corresponding to the eighth contact point P8 of the proximal end side spiral portion 423. Therefore, at the same depth of the hole H, the portion where the first contact portion 41 is in contact with the inner peripheral surface Ic of the hole H and the proximal end side spiral portion 423 are in contact with the inner peripheral surface Ic of the hole H. When the portions are compared in the radial direction B, the first contact point 41 is in contact with the inner peripheral surface Ic of the hole H, and the proximal end side spiral portion 423 is in contact with the inner peripheral surface Ic of the hole H. There is a point where the contact points that are in contact with each other do not match in the radial direction B and are deviated in the axial direction A.

If the first per portion 41 and the second per portion 42 each extend at the first helix angle α, the first per portion 41 and the second per portion 42 have the inner peripheral surface Ic at the same depth of the hole H. Contact. As a result, the sound generated when the first contact portion 41 and the second contact portion 42 each come into contact with the inner peripheral surface Ic at the same depth of the hole H is likely to resonate.

In that respect, as described above, at the same depth of the hole H, the portion where the first per portion 41 is in contact with the inner peripheral surface Ic of the hole H and the second per portion 42 are the inner peripheral surface Ic of the hole H. When the portion in contact with the hole H is compared in the radial direction B, the contact point where the first contact portion 41 is in contact with the inner peripheral surface Ic of the hole H and the second contact portion 42 are the inner circumference of the hole H. There is a point where the contact point in contact with the surface Ic does not match in the radial direction B and is deviated in the axial direction A. Therefore, unlike the case where each of the first per portion 41 and the second per portion 42 extends at the first helix angle α, the resonance of sound is suppressed.

The effect of this embodiment will be described.
(1) Unlike the case where each of the first per portion 41 and the second per portion 42 extends at the first helix angle α, the resonance of sound can be suppressed. Therefore, the noise when cutting the work W with the drill 10 can be reduced.

(2) If the second per portion 42 continues to extend at the intermediate helix angle β, the second per portion 42 intersects the first per portion 41 due to the design of the drilling drill 10. In the present embodiment, the proximal end side spiral portion 423 extending from the intermediate spiral portion 422 at the proximal end helix angle γ is provided. Therefore, it becomes difficult for the extended end of the second per portion 42 to intersect with the first per portion 41. Therefore, in the design of the drilling drill 10, the function of the drilling drill 10 as a drill can be maintained.

(3) Considering that the first contact portion 41 and the second contact portion 42 come into surface contact with the inner peripheral surface Ic of the hole H, and the noise when cutting the work W with the drill 10 may be loud. Suppressing the resonance of sound due to the contact between the first contact portion 41 and the second contact portion 42 with the inner peripheral surface Ic of the hole H has the effect of reducing noise when cutting the work W with the drilling drill 10. Can be noticeable.

In addition, this embodiment can be changed and carried out as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
The twist angle of the tip-side spiral portion 421 may be gradually increased so that the twist angle becomes an intermediate twist angle β so that the tip-side spiral portion 421 extends from the second blade 22 in the direction opposite to the rotation direction C. That is, the first helix angle α may be a variable rather than a constant.

○ The helix angle of the intermediate spiral portion 422 is gradually increased so that the helix angle becomes the proximal end twist angle γ so that the intermediate spiral portion 422 extends in the direction opposite to the rotation direction C from the extended end of the distal end side spiral portion 421. You may. The intermediate helix angle β may be a variable rather than a constant.

○ The base end helix angle γ of the base end side spiral portion 423 may be changed so that the helix angle gradually decreases as it extends from the extended end of the intermediate spiral portion 422 toward the direction opposite to the rotation direction C. .. The proximal twist angle γ may be a variable rather than a constant.

○ As in the above modification example, the helix angle of each of the tip side spiral portion 421, the intermediate spiral portion 422, and the proximal end side spiral portion 423 may be used as variables. That is, the helix angle of the second per portion 42 may always change from the second blade 22 toward the second end 12. That is, the second helix angle may be a variable different from the first helix angle α.

○ It is sufficient that at least one helix angle of the intermediate spiral portion 422 and the proximal end side helix portion 423 extends at a second helix angle different from the first helix angle α. Further, the second per portion 42 is not limited to being composed of the tip side spiral portion 421, the intermediate spiral portion 422, and the proximal end side spiral portion 423, and the intermediate helix angle β or the proximal end is always in the entire length in the axial direction A. It may be changed so as to extend at the helix angle γ, or it may be changed so as to always extend at a second helix angle different from any of the first helix angle α, the intermediate helix angle β, and the proximal helix angle γ.

○ The tip-side spiral portion 421 may be a portion of the second per portion 42 that extends from the second blade 22 in the direction opposite to the rotation direction C by the amount of the first predetermined angle. Further, the intermediate spiral portion 422 may be a portion of the second peripheral portion 42 that extends from the extended end of the distal end side spiral portion 421 in the direction opposite to the rotation direction C by a second predetermined angle. Further, the proximal end side spiral portion 423 may be a portion of the second peripheral portion 42 that extends from the extended end of the intermediate spiral portion 422 in the direction opposite to the rotation direction C by a third predetermined angle. That is, the lengths of the distal end side spiral portion 421, the intermediate spiral portion 422, and the proximal end side spiral portion 423 may be appropriately changed.

○ The second contact portion 42 is composed of the tip side spiral portion 421, the intermediate spiral portion 422, and the proximal end side spiral portion 423, and the helix angle increases from the first end 11 to the second end 12 of the drilling drill 10. It changed twice, but it is not limited to this. For example, the second perimeter portion 42 may be configured so that the helix angle changes three times from the first end 11 to the second end 12 of the drilling drill 10, or the helix angle changes four or more times. It may be configured as follows.

○ The first per part 41 and the second per part 42 are examples of a plurality of per parts, but a third per part may be added. In this case, the third per part may have the same configuration as the first per part 41, or may have the same configuration as the second per part 42. Further, the third per part may have a different configuration from the first per part 41 and the second per part 42. Further, there may be four or more hit portions. When increasing the number of a plurality of contact portions, a new cutting edge is added to the first end 11 of the drilling drill 10 in addition to the first blade 21 and the second blade 22. Then, the added contact portion from the added new cutting edge is configured to extend spirally toward the second end 12.

○ The rake angles of the first blade 21 and the second blade 22 may be different.

10 ... Drilling drill, 11 ... 1st end, 12 ... 2nd end, 21 ... 1st blade, 22 ... 2nd blade, 31 ... 1st helix groove, 32 ... 2nd helix groove, 41 ... 1st perforation, 42 ... 2nd helix part, 421 ... Tip side spiral part 422 ... Intermediate spiral part 423 ... Base end side spiral part, m ... Axial line, A ... Axial direction, B ... Radial direction, C ... Rotation direction, θ1 ... Scoop Angle, α ... 1st helix angle, β ... Intermediate helix angle, γ ... Base end helix angle, W ... Work, H ... Hole, Ic ... Inner peripheral surface, Bd1 ... Boundary, Bd2 ... Boundary.

Claims (2)

A drill that rotates around an axis,
Multiple blades provided at the first end in the axial direction,
A plurality of spiral abutments extending from each of the plurality of blades toward the second end in the axial direction, and
It is provided with a spiral twisted groove provided between the contact portions adjacent to each other in the rotation direction about the axis and extending along the contact portion.
The plurality of the above-mentioned hit parts
The first hitting part, which is the hitting part extending at the first helix angle, and the first hitting part,
A drilling drill comprising: a second hit portion which is the hit portion having at least a portion extending at a second twist angle which is a twist angle different from the first twist angle. The second part is
The tip-side spiral portion extending from the blade at the first helix angle,
An intermediate spiral portion extending from the tip side spiral portion at an intermediate twist angle which is the second helix angle larger than the first helix angle, and
The drilling drill according to claim 1, further comprising a proximal end side spiral portion extending from the intermediate spiral portion at a proximal end torsion angle which is a dihedral helix angle smaller than the intermediate torsion angle.

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