JP4231497B2 - Replaceable tip drill - Google Patents

Description

  The present invention relates to a blade-tip replaceable drill using a throw-away tip used for drilling metal or the like.

The following two types of blade-tip-replaceable drills are known in which at least two throwaway tips are attached to the tip of the drill body, and a cutting edge is formed with the throwaway tip.
As shown in FIG. 16, a flat placement type blade tip replacement in which two polygonal plate-shaped throwaway tips 15 are placed in a flat placement where the upper surface or the lower surface of the tip is a rake face is mounted on the tip of the drill body 1. The type drill 20 is the most common, but as shown in FIG. 17, two throwaway tips 25 are mounted in a vertical arrangement in which the side surfaces of the tips are scooped at the tip of the drill body 1. There is also a stand type drill 30. Note that the blade tip replaceable drill 30 in FIG. 17 is disclosed in Patent Document 1 below.

  The cutting edge replaceable drill 20 shown in FIG. 16 in which the throw-away tip is placed flat can secure a large area of the rake face and can improve chip disposal. In addition, this drill has a central blade and an outer peripheral blade formed of separate chips, and the axial rake angle of the outer peripheral blade can be set without being restricted by the central blade, improving sharpness and resulting cutting power. There is an advantage that it is easy to reduce. However, in this flat placement type blade-tip-exchangeable drill, it is difficult to increase the strength of the tip because the cutting load acts on the tip in the thickness direction. Further, in the flat placement arrangement, the tip seats provided in the drill main body are both elongated in the axial direction, so that the rigidity reduction of the drill main body is larger than that of the vertical placement type.

On the other hand, the tip-replaceable drill 30 shown in FIG. 17 in which the throwaway tip is placed vertically improves the tip strength, but has a small rake face area that can be ensured, resulting in poor chip disposal. In addition, the number of corners of the cutting edge is small, and there is a problem in economy. In addition, since one cutting edge is formed by one throw-away tip, the tip price increases as the processing diameter increases.
JP-T-2004-501780

  This invention makes it the subject to make compatible the ensuring of the chip | tip intensity | strength and main body intensity | strength in a blade-tip-exchange-type drill, and the improvement of chip disposal property. In addition, it is an object to increase the number of used corners of a chip, reduce cutting resistance by improving sharpness, and reduce cutting power, if necessary.

In order to solve the above-described problems, in the present invention, a plurality of throw-away tips are mounted on a drill body in a vertical arrangement in which the side surface of the tip is a rake surface and a flat surface in which the upper surface or the lower surface of the tip is a rake surface. The placement was mixed.
In addition, each throwaway tip uses a throwaway tip of the same specification having a first ridge line at a position where the upper surface and the side surface intersect, and a second ridge line at a position where the lower surface and the side surface intersect with each other. A cutting edge was formed at the second ridgeline .

The preferable aspect of this blade-tip-exchange-type drill is enumerated below.
(1) The throw-away tip is placed on the rotation center side and the outer diameter side of the drill, the throw-away tip placed on the rotation center side of the drill is placed vertically, and the throw-away tip placed on the outer diameter side of the drill is placed flat The work area is divided and cut with the throw-away tip arranged vertically and the throw-away tip arranged flat.
(2) As a throw-away tip, a polygonal throw-away tip having a ridge line between each corner as a cutting edge is used.
(3) A cutting blade having a chevron shape in a front view of the drill is formed with a throw-away tip arranged vertically, and a cutting blade having a chevron shape in a side view of the drill is formed with a throw-away tip placed in a flat position.

  Since the drill according to the present invention mixes the vertical placement of chips and the flat placement, a center blade (cutting blade portion near the rotation center) utilizing the advantages of the vertical placement in the configuration of (1) above, Peripheral blades (cutting blade portions radially outside of the center blade) that take advantage of the flat placement can be formed respectively.

  The cutting speed of the drill decreases as it approaches the center of rotation, and becomes zero at the center of rotation. Therefore, it is preferable that the center blade emphasizes the chip strength rather than the sharpness and chip disposal, and the demand can be met by arranging the chips vertically. In addition, the outer peripheral blade with a large amount of cutting can reduce cutting resistance, in other words, one that emphasizes chip disposal and sharpness, and the throwaway tip is placed flat to reduce the area of the rake face. It is possible to meet the demand by ensuring a wide range and further relaxing the setting of the rake angle of the outer peripheral blade by making the outer peripheral blade independent of the central blade.

  In addition, by mixing the vertical placement and the flat placement, the axial installation range of the tip seat for mounting the throw-away tip in the vertical placement is shortened, so it is possible to suppress a decrease in strength on the tip side of the drill body. .

In addition , since the throwaway tip of the same specification having the first ridge line on the upper surface side and the second ridge line on the lower surface side is arranged vertically and horizontally, the cutting edge is formed by the first ridge line and the second ridge line ,
The economic effect can be enhanced by increasing the number of corners of the chip used.

  In addition, those using a polygonal throw-away tip can perform a corner change and use the ridge line between the corners as a cutting edge, which increases the economic effect.

  In addition, when the throw-away tip arranged vertically and the throw-away tip arranged flat are each formed with a chevron-shaped cutting edge, chips that are easily divided are generated, and chip disposal is improved. In addition, the angle cutting edge of the chevron is counteracted by the drill radial component forces in opposite directions on the right and left sides of the peak of the mountain during drilling, and the forces cancel each other, so that the rotation balance of the drill is improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cutting edge replaceable drill (hereinafter simply referred to as a drill) according to the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 to 8, the example drill 10 is provided with two twist grooves (chip grooves) 2, 2 on the outer periphery of the drill body 1, and is provided at the most distal end of each twist groove 2, 2. The tip seats 3 and 4 are each configured with one throw-away tip 5 attached thereto.

  As shown in FIGS. 9 and 10, the throwaway tips 5 and 5 have the first ridge line 5d at the position where the upper surface 5a and the side surface 5b intersect, and the second ridge line 5e at the position where the lower surface 5c and the side surface 5b intersect. It is a chip with the same specifications. The side surface 5b intersects the upper surface 5a at an acute angle, so that the cutting edge formed by the first ridge line 5d is a sharp blade with good sharpness. Further, the side surface 5b intersects with the lower surface 5c at an angle of approximately 90 degrees, so that the cutting edge formed by the second ridge line 5e is a reinforced blade than the cutting edge formed by the first ridge line 5d. .

  The throw-away tips 5 and 5 having parallel upper and lower surfaces 5a and 5b are mounted on the center of rotation of the drill body 1 with one tip placed vertically and the other tip placed horizontally and the drill body 1 It is mounted on the outer peripheral side of the.

  In the throw-away tip 5 mounted in a vertically arranged manner on the tip seat 3 on the rotation center side of the drill, the side surface 5b serves as a rake face, the lower surface 5c serves as a flank face of the drill tip, and the second ridge line 5e serves as a cutting edge. Further, the throw-away tip 5 mounted in a flat position on the tip seat 4 on the outer peripheral side of the drill has an upper surface 5a serving as a rake face and a side surface 5b serving as a flank, and the first ridge line 5d serves as a cutting edge.

  In the illustrated drill, the cutting edge formed by the second ridge line 5e is the center cutting edge 6a, and the cutting edge formed by the first ridge line 5d is the outer peripheral cutting edge 6b. Two throwaway tips 5 and 5 are arranged so that the trajectories of the central blade 6a and the outer peripheral blade 6b partially overlap, and the work area is shared by the two throwaway tips 5 and 5. To be cut. The throw-away tip 5 mounted vertically on the tip seat 3 can secure a sufficient amount of back metal and exhibit high strength. Further, the throw-away tip 5 mounted in the tip seat 4 in the flat placement can arbitrarily set the axial rake angle θ (see FIG. 7) without being restricted by the throw-away tip in the vertical placement. The sharpness can be ensured by setting the axial rake angle θ to a positive angle.

  The throw-away tip 5 employed in the illustrated drill is a tip having a triangular shape as a basic shape, and the first ridge line 5d and the second ridge line 5e are both finished in a mountain shape, and the center edge 6a is formed. There are three first ridge lines 5d formed between the two ridge lines 5e and the outer peripheral edge 6b as shown in FIGS. Therefore, a total of 6 corners can be used, which is excellent in economic efficiency. As shown in FIG. 11, when the throw-away tip 5 placed vertically is rotated approximately 90 degrees and moved to the tip seat 4, it becomes the throw-away tip 5 placed flat, and the throw-away tip 5 placed flat is almost When it is rotated 90 degrees and moved to the chip seat 3, the throw-away chip 5 is placed vertically. By repeating the rotation, 6 corners can be used without waste.

  In order to improve chip disposal, a position along the first ridge line 5d of the upper surface 5a of the throw-away tip 5 and a position along the second ridge line 5e of the side surface 5b are formed with grooves, protrusions, wrinkles and the like. The tip-away tip 5 employed in the illustrated drill is provided with breaker grooves 5f and 5g on the upper surface 5a and the side surface 5b, respectively (see FIGS. 7 and 8).

  Note that the throw-away tip 5 is not limited to the illustrated shape. The basic shape may be a polygon other than a triangle, for example, a rectangle or a square. In addition, the illustrated throw-away tip 5 has the corner portion of the lower surface 5c inclined to escape to the upper surface side. For this reason, the region where the second ridge line 5e functions as the central blade 6a is the point a-b in FIG. In this range, the corner portion having low strength is not involved in cutting and the corner portion is protected, but it is not essential to escape the corner portion of the lower surface 5c.

  In addition, the method for fixing the throw-away tip 5 to the drill body 1 is not particularly limited. The drill shown in FIGS. 1 to 8 has a method in which a clamp screw 7 is passed through a clamp hole 5 h provided in the throw-away tip 5 and the throw-away tip 5 is tightened with the clamp screw 7 screwed into the drill body 1. Is fixed to the drill body 1, but the throw-away tip can be fixed by other methods.

  12 to 13 show other examples of the chip fixing method. Here, split grooves 8 and 9 are provided at the tip of the drill body 1 to divide the chip seats 3 and 4 into two parts vertically, and the vertical part is tightened with a so-called double screw 11 to insert the chip seat 3. The throw-away tip 5 attached to 4 is clamped by the drill body 1 (see FIGS. 13 and 14). Depending on the shape of the throw-away tip to be used, this structure requires measures to prevent the tip from popping out from the tip seats 3 and 4 (simple measures such as fitting the drill body to the tip) There is an advantage that a chip without a clamp hole can be used.

Side view showing an example of the drill of the present invention Front view of the drill of FIG. The perspective view of the front end side of the drill of FIG. 1 is an enlarged side view of the main part of the drill of FIG. 1 is an enlarged side view of the position obtained by rotating the drill of FIG. 1 by 90 degrees. 1 is an enlarged front view of the drill of FIG. The expanded sectional view of the position along the AA line of FIG. The expanded sectional view of the position along the BB line of FIG. A perspective view of the throw-away tip as seen from the bottom side A perspective view of the throw-away tip as seen from the top side Diagram showing the replacement state of vertical and flat throw-away tips Front view showing another embodiment of the drill of the present invention The expanded perspective view which shows the front end side of the drill of FIG. The expanded sectional view of the position along the CC line of FIG. The expanded sectional view of the position along the DD line of FIG. The perspective view which shows the prior art example of a blade-tip-exchange-type drill The perspective view which shows the other conventional example of a blade-tip-exchange-type drill

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drill main body 2 Torsion groove | channel 3, 4 Tip seat 5 Throw away tip 5a Upper surface 5b Side surface 5c Lower surface 5d 1st ridgeline 5e 2nd ridgeline 5f, 5g Breaker groove 5h Clamp hole 6a Center blade 6b Peripheral blade 7 Clamp screw 8,9 Split Groove 10 Drill 11 Double screw

Claims (4)

In a tip-changing drill in which a plurality of throw-away tips are attached to the tip of the drill body, and a plurality of throw-away tips are used to form a cutting edge, the throw-away tip is attached to the drill body. a vertical arrangement becomes the rake face, have rows mix placed flat the upper surface or lower surface of the cutting insert becomes the rake face, each of the cutting insert, a first ridge line at a position upper and side surfaces intersect A blade- tip-replaceable drill characterized by using a throw-away tip of the same specification having a second ridge line at a position where the lower surface and the side surface intersect, and forming a cutting edge by the first ridge line and the second ridge line .   The throw-away tip is placed on the rotation center side and the outer diameter side of the drill, the throw-away tip placed on the drill rotation center side is placed vertically, and the throw-away tip placed on the outer diameter side of the drill is placed flat. The cutting edge-replaceable drill according to claim 1, wherein the cutting area is dividedly cut by a throw-away tip of a vertical placement and a flat placement. The blade tip-replaceable drill according to claim 1 or 2 , wherein a polygonal throw-away tip having a ridge line between each corner as a cutting edge is used as the throw-away tip. Claim a cutting edge forming a chevron in vertical arrangement of the throw-away tip in a front view of the drill, and forming respectively a cutting edge forming a chevron in a side view of the drill with indexable insert disposed flat 1 indexable drill according to any one of to 3.

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