JP2006239829A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve abrasion of a knife edge and a rake face of a cutting blade by improving a cooling effect and a lubricating effect in the neighborhood of a cutting point by cutting fluid on a drill. <P>SOLUTION: This drill is constituted by opening an oil hole 10 on its head end flank 6, extending toward the cutting blade 4 positioned near by the front side in the rotating direction K of an opening part 10a from the opening part 10a of the oil hole 10 and forming at least one of recessed groove type channels 11a, 11b opened to a chip discharging groove 3 by cutting out the cutting blade 4. It is possible to extensively improve a tool life of the drill as abrasion of the knife edge and a flank 5 is restrained since a sufficient amount of the cutting fluid is certainly supplied by the channels 11a, 11b and a cooling effect and a lubricating effect by the cutting fluid are extensively improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a drill having an oil hole for supplying a cutting fluid into a drill body.

This type of conventional drill is shown in FIGS. The drill shown in FIG. 3 is intended to prevent tool breakage and enhance the cooling effect. An oil hole is opened in the tip flank provided at the tip of the drill, and the center O2 of the opening is It is located at a distance of 0.01D or more and 0.15D or less (D: drill diameter) from the edge of the cutting edge in a front view of the drill tip, and further 0.08D or more and 0.23D or less from the outer peripheral edge of the drill's rotation trajectory. It is characterized by being located at a distance of (D: drill diameter) (for example, see Patent Document 1).

The drill shown in FIG. 4 is intended to efficiently supply the cutting fluid to the inner peripheral side of the tool, and the cutting fluid supply hole formed along the axis of the tool body has a tip flank surface. It is characterized by opening on the axis (for example, see Patent Document 2).

The drill shown in FIG. 5 is intended to enhance the cooling effect and lubrication effect of the rake face by the cutting fluid, and has an oil hole opened in the rake face or margin (for example, see Patent Document 3). ).

JP 2002-52410 A JP 2000-33510 A Japanese National Patent Publication No. 11-508829

However, in the drills disclosed in Patent Document 1 and Patent Document 2, a sufficient amount of cutting fluid can be supplied to the tip flank surface, but because it scrapes against the work material and chips, the cutting edge of the cutting blade that becomes high temperature and high pressure and Since the cutting fluid hardly reaches the rake face in the vicinity of the cutting edge, that is, in the vicinity of the cutting point, a high cooling effect and lubricating effect cannot be obtained. Therefore, there has been a problem that crater wear on the rake face proceeds rapidly and the tool life is shortened.

In the drill disclosed in Patent Document 3, although the amount of the cutting fluid supplied to the rake face increases because the opening of the oil hole is provided on the rake face, the opening is close to the cutting edge of the cutting edge. As a result, the cutting fluid could not be efficiently supplied in the vicinity of the cutting point. Therefore, the cooling effect and the lubricating effect in the vicinity of the cutting point were not satisfactory. Furthermore, since the chips in the chip discharge groove are blocked from being discharged by the openings, or are clogged by the openings or damage the openings, the chip discharge performance, the amount of cutting fluid discharged, and the life of the drill body There was a risk of adverse effects.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drill that improves the cooling effect and the lubricating effect in the vicinity of the cutting point by the cutting fluid to improve the wear of the cutting edge and the rake face. It is to provide.

In order to solve the above-mentioned problems, the present invention provides a pair of chip discharge grooves formed on the outer peripheral surface of a drill body that rotates about the axis (CL) with the axis (CL) interposed therebetween, and the chip discharge A pair of cutting edges are formed at the intersecting ridge line portion between the groove and the tip flank of the tip of the drill body, and an oil hole for supplying cutting fluid from the rear end surface of the drill body toward the tip side is formed. In each of the drills, each of the tip flank faces has an oil hole, and extends from the opening of the oil hole toward a cutting blade positioned on the front side in the rotation direction (K) of the opening, and It is a drill characterized in that at least one groove-shaped channel opening in the chip discharge groove is formed by cutting out the cutting blade.

In the drill described above, it is preferable that the notch portions of the cutting blades notched by the flow path do not overlap in the rotation trajectory around the axis (CL), and the notch portions are not involved in cutting. .

According to the above-described drill, it extends from the opening of the oil hole toward the cutting edge located on the front side in the rotation direction (K) of the opening, and opens into the chip discharge groove by cutting out the cutting edge. Since the groove-shaped flow path is formed, a sufficient amount of cutting fluid can be reliably supplied near the cutting point, and the cooling effect and lubrication effect on the cutting edge of the cutting edge and the rake face near the cutting edge are greatly improved. Enhanced. Therefore, the wear of the cutting edge and the rake face is suppressed, and the tool life of the drill is greatly improved.

Furthermore, since the notch portion of the cutting edge cut out by the flow path does not participate in cutting, the chip is divided finely, so that the chip discharge performance is improved and the tool vibration and vibration are reduced by reducing the cutting resistance such as torque and thrust. Since tool chatter is suppressed, the cutting performance and tool life of the drill are improved.

Next, an embodiment to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a front view of the tip of a drill to which the present invention is applied. FIG. 2 is a side view of the drill shown in FIG. In this drill, the drill body (1) has a substantially round bar shape rotated about the axis (CL), the blade (2) formed at the tip, and the rear end connected to the blade (2). It is comprised from the shank part (not shown) formed in this. On the outer peripheral surface of the blade portion (2), as illustrated in FIG. 1, a pair of twists from the tip flank (6) at the tip of the drill body (1) toward the rear end side in the axial center (CL) direction. Crossing ridge line portion between the wall surface in which the chip discharge grooves (3) are formed and facing the front side in the rotational direction (K) of the chip discharge grooves (3) and the tip flank (6) at the tip of the drill body (1) A pair of cutting edges (4) is formed in the. At least the cutting edge (4) is made of any hard material such as cemented carbide, cermet, ceramics or the like. Furthermore, a margin (7) provided continuously to the outer peripheral end portion of the cutting blade (4) extends toward the rear end side in the axial center (CL) direction.

On the inner peripheral side of these cutting blades (4), a thinning blade (9) is formed by applying a thinning (8) to the tip of the drill body (1). As illustrated in FIG. 2, these thinning blades (9) intersect each of the cutting blades (4) at an obtuse angle when viewed from the tip of the drill, and the intersecting portion has a smooth curved shape, and the tip of the drill body (1). Is formed so as to extend linearly toward the axis (CL) side. The tip clearance surface (6) at the tip of the drill body (1) has a plurality of tips whose clearance angles increase stepwise from the cutting blade (4) and the thinning blade (9) toward the rear side in the rotational direction (K). It consists of flank faces (6a-6c). A first tip flank (6a) connected to each of the cutting edges (4) and the thinning blade (9), and a second tip flank connected to the rear side in the rotational direction (K) of the first tip flank (6a) ( 6b) is formed so as to be substantially parallel to the cutting edge (4). The second tip flank (6b) and the rotational direction (K) rear side of the second tip flank (6b) The intersecting ridge line with the continuous third tip flank (6c) is formed so as to intersect the straight portion of the thinning blade (9) at a substantially right angle.

In the drill body (1), two oil holes (10) having a substantially circular cross section are formed from the rear end surface (not shown) of the shank portion toward the front end side. As can be seen from FIG. 2, the two oil holes (10) open to the respective second tip clearance surfaces (6b). And the flow path (11a, 11b) extended toward the cutting edge (4) located in the rotation direction (K) front side of the said opening part (10a) from the opening part (10a) of these oil holes (10). It is formed. In this drill, each flow path (11a, 11b) cuts out the inner wall surface located in the rotation direction (K) front side of the opening part (10a) of the oil hole (10) and the second tip flank (6b). ) And a first groove that forms a recess on the surface of the first tip flank (6a), and a cut located in the rotational direction (K) front side of the opening (10a) of the oil hole (10). It extends linearly toward the blade (4) and opens into the chip discharge groove (3) by cutting out a part of the cutting blade (4).

Although not shown in the drawing, when the drill diameter (D) is small or when the flow path (11a, 11b) is extended toward the outer peripheral end of the cutting edge (4), the flow path (11a, 11b) In order to avoid an increase in the wall thickness of the portion sandwiched between the outer peripheral wall surface and the outer peripheral surface of the drill body (1), the flow path (11a, 11b) has a convex curve shape toward the outside in a front end view. You may form in. In addition, the cross-sectional shape of the flow path (11a, 11b) is a U-shape composed of a straight side wall and an arc-shaped bottom as illustrated in FIG. It can be appropriately selected from shapes such as a semicircular shape or a U-shape.

The notches (4a, 4b) of the cutting edge (4) cut out by these flow paths (11a, 11b) are formed at different positions in the radial direction so that the rotation trajectories around the axis (CL) do not overlap. Is done. Furthermore, the notches (4a, 4b) are formed so as not to participate in cutting during drilling. In short, the notches (4a, 4b) are formed to act as nicks. Furthermore, it is necessary to provide a gap between the notches (4a, 4b) and the work material when drilling with the drill. Therefore, the retreating amount (H) with respect to the cutting edge (4) ridgeline of the deepest part of the notch (4a, 4b) in the axial center (CL) direction is a value obtained by dividing the feed amount per one rotation of the drill by the number of blades. Is set larger than. If the retraction amount (H) is excessive, the strength of the cutting edge (4) in the vicinity of the notches (4a, 4b) is reduced or the notches (4a, 4b) and the flow paths (11a, 11b) are processed. Therefore, it is preferable to set the amount to 50 times or less of the feed amount or 50% or less of the drill diameter (D).

The width (W) of the notches (4a, 4b) is formed to be substantially equal to the diameter of the oil hole (10) as illustrated in FIG. 2, but is smaller or larger than the diameter of the oil hole (10). However, if the amount is too small, the flow rate of the cutting fluid may be insufficient. If the amount is too large, the strength of the tip of the drill body (1) may be reduced. ) Is preferably set in the range of 30% to 200% of the inner diameter of the oil hole (10).

In order to prevent the flow paths (11a, 11b) from interfering with the work material during drilling, the bottom surface and both wall surfaces of the flow paths (11a, 11b) are formed so as to have relief from the work material. It is. By doing so, an increase in cutting resistance can be avoided, and damage to the flow paths (11a, 11b) and obstruction of the flow of the cutting fluid in the flow paths (11a, 11b) can be avoided.

The flow paths (11a, 11b) extending from the opening (10a) of one oil hole (10) are not limited to one but may be two or more. In the case of forming the flow path (11, 11b), it is formed by a known processing method such as grinding using a grindstone, electric discharge processing, or laser beam processing, and is a sintered alloy such as cemented carbide or cermet. Alternatively, it may be formed by molding before sintering.

According to the drill described above, a part of the cutting fluid discharged from the opening (10a) of the oil hole (10) toward the bottom of the machining hole rotates in the flow path (11a, 11b). (K) It flows toward the notch (4a, 4b) of the cutting edge (4) located on the front side, and flows from the notch (4a, 4b) to the rake face (5) side to the cutting edge (4). The cutting edge and the rake face (5) in the vicinity of the cutting edge, that is, the vicinity of the cutting point are surely reached. In addition, since a sufficient amount of the cutting fluid is supplied in the vicinity of the cutting point, the cooling effect and the lubricating effect of the cutting fluid are greatly enhanced. Accordingly, the wear of the cutting edge (4) and the crater wear of the rake face (5) are suppressed, and the tool life of the drill is greatly improved. Since the cutting fluid flows between the tip flank (6) and the bottom of the machining hole as in the conventional drill, and flows into the chip discharge groove (3) on the rear side in the rotational direction (K), the tip flank (6) As for the wear-inhibiting effect and chip evacuation effect, the effect equivalent to that of a conventional drill can be obtained.

The notches (4a, 4b) of the cutting edge (4) formed by notching with the flow paths (11a, 11b) have the same effect as the nick. In other words, fine chip cutting improves chip discharge performance, reduces cutting resistance such as torque and thrust, and suppresses tool vibration and tool chatter, improving drilling accuracy and drill tool life. To do.

As illustrated in FIG. 5, in the conventional drill in which the opening portion of the oil hole is provided at a position separated from the cutting edge ridge line of the rake face, the chips in the chip discharge groove are blocked from flowing by the opening portion or the opening. However, in this drill, the notches (4a, 4b) may be adversely affected on chip discharge, cutting fluid discharge rate and drill body life. ) Is provided on the edge of the cutting edge (4) and does not generate chips, so there is no such problem. Moreover, since the flow paths (11a, 11b) are provided on the surface of the tip flank (6) where the chips hardly flow, the chips do not clog and prevent the cutting fluid from flowing. Therefore, the chip dischargeability is good, and a sufficient amount of the cutting fluid flowing through the flow paths (11a, 11b) and the notches (4a, 4b) is stably secured. The cooling effect and the lubricating effect are reliably and sufficiently obtained.

The flow path (11a, 11b) of the present drill can be additionally processed by the above-described manufacturing method with respect to the existing drill having an oil hole on the tip flank, and the additional process is very easy. .

It is a front view of the front-end | tip part of the drill to which this invention is applied. It is a front view side view of the drill shown in FIG. It is a figure which shows the drill with a conventional oil hole. It is a figure which shows another conventional drill with an oil hole. It is a figure which shows the other conventional drill with an oil hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drill main body 2 Blade part 3 Chip discharge groove 4 Cutting edge 4a, 4b Notch part 5 Rake face 6 Tip flank 6a First tip flank 6b Second tip flank 7c Third tip flank 7 Margin 8 Thinning 9 Thinning blade DESCRIPTION OF SYMBOLS 10 Oil hole 10a Oil hole opening part 11a, 11b Flow path

Claims (2)

A pair of chip discharge grooves are formed on the outer peripheral surface of the drill body rotating about the axis (CL) with the axis (CL) interposed therebetween, and the chip discharge grooves and the tip flank at the tip of the drill body In the drill in which a pair of cutting blades are formed in the crossed ridge line portion, and an oil hole for supplying a cutting fluid from the rear end surface of the drill body toward the tip side is formed,
Each of the tip flank faces has an oil hole, and extends from the opening of the oil hole toward a cutting blade located on the front side in the rotational direction (K) of the opening, and the cutting blade is A drill characterized in that at least one groove-shaped channel opening in the chip discharge groove is formed by cutting. 2. The notch of each of the cutting blades notched by the flow path does not overlap in a rotation locus around the axis (CL), and the notch is not involved in cutting. The drill described.

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