JPH0674215U - Drilling tool - Google Patents

Abstract

(57) [Summary] [Structure] The groove wall surface 6 of the chip discharge groove 5 provided in the blade portion at the tip of the tool body 1 facing the tool rotation direction is located on the radially inner side groove wall surface 6a and on the radially outer side. And the outer peripheral side groove wall surface 6b which is retracted one step rearward in the tool rotation direction to form a multi-step shape, and the cutting edge 8 formed at the ridge line portion where the groove wall surface 6a, 6b and the tip end surface 7 intersect with each other in the radial direction. The inner peripheral side cutting edge portion 8a which is located at the tip end side and extends in the radial direction when viewed in the direction of the axis O from the tip side, and the radially outer side of the inner peripheral side cutting blade portion 8a, the rear side in the tool rotation direction and the base end in the axial direction O. It is formed from the outer peripheral side cutting edge portion 8b located on the side. [Effect] It is possible to improve the sharpness by giving a positive radial rake angle θ to the outer peripheral side cutting edge portion 8b, prevent burrs when forming the through holes, and improve the surface accuracy. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a drilling tool such as a gun drill or a gun reamer used for drilling.

[0002]

[Prior art]

 Among the drilling processes, gandrill and gun reamer are known as drilling tools used especially for drilling deep holes. In these drilling tools, a cutting edge tip made of a hard material such as cemented carbide is attached to the tip of the tool body that has an axial shape, and a blade portion is provided. At least one chip discharge groove is formed along the axial direction of the tool, and further, from the tip side of the tool body, at the ridge line intersection of the wall surface of the chip discharge groove facing the tool rotation direction and the tip surface of the blade part. The cutting edge is formed so as to extend in the radial direction of the tool body as viewed in the axial direction. Therefore, with respect to this cutting edge, the groove wall surface is a rake surface, and the tip end surface is a flank surface. The groove wall surface is generally formed in a direction including or parallel to the axis line, whereby the axial rake angle of the cutting edge is set to 0 °.

Further, in the gun reamer, a cutting edge is formed on the ridge line portion on the outer peripheral side of the groove wall surface so as to be continuous with the cutting edge, and is connected to the cutting blade and the rear side in the tool rotation direction. The margin is used to finish the inner circumference of the hole. Further, an oil hole is usually formed from the tool body to the blade portion, and this oil hole is opened at the tip surface of the blade portion, and by supplying the oil agent from the machine tool side through this oil hole. , The chips produced by cutting are discharged and the work material and the blade are cooled.

[0004]

[Problems to be solved by the device]

 By the way, not limited to such a gun drill or gun reamer, when forming a through hole in a work material with a drilling tool or finishing the inner circumference of the through hole, the exit of this through hole is used. The problem is that burr is generated in the side opening. Such burrs occur when the uncut portion of the work material becomes thin just before the hole penetrates, and this portion is pushed and spread as the tool is fed before it is completely removed. If such burrs occur, it goes without saying that deburring must be performed after the drilling by the drilling tool is finished, which may complicate the machining process and deteriorate the machining efficiency. turn into. In particular, such burrs are remarkable when the work material is made of a relatively soft material. Therefore, for example, when a through hole is formed in a work material made of aluminum, deburring is performed. It was unavoidable that the machining process was complicated due to machining.

[0005]

[Means for Solving the Problems]

 The present invention has been made to solve such a problem, in which a blade portion is provided at the tip of a tool body rotated around an axis, and at least one chip discharging groove is provided on the outer periphery of the blade portion. In a drilling tool that is formed along the above-mentioned axial direction and has a cutting edge formed at the ridge line intersecting the groove wall surface facing the tool rotation direction of the chip discharge groove and the tip end surface of the blade section. , The groove wall surface is located inside the tool body in the radial direction and extends in the radial direction, and the groove wall surface is located outside the tool body in the radial direction, and the inner wall surface is located one step rearward in the tool rotation direction. The cutting edge is formed in a multi-step shape having a recessed outer peripheral side groove wall surface, and the cutting edge is also formed on an intersecting ridge line portion between the inner peripheral side groove wall surface and the leading end surface and is located inside the radial direction. Extending in the above radial direction when viewed from the above axial direction from the tip side of the main body It is formed on an inner peripheral side cutting edge portion, a ridge line portion intersecting the outer peripheral side groove wall surface and the front end surface, and is on the outer side in the radial direction of the inner peripheral side cutting edge portion, on the rear side in the tool rotation direction, and on the above side. It is formed from a plurality of cutting edge portions located on the axially proximal end side and having an outer peripheral cutting edge portion extending parallel to the inner peripheral cutting edge portion when viewed in the axial direction from the tool body distal end side. Characterize.

[0006]

[Action]

 In the drilling tool having the above-mentioned configuration, the cutting edge formed at the tip of the tool body is formed by a plurality of cutting edge parts, of which the inner cutting edge located on the inner side in the radial direction of the tool body and on the tip side in the axial direction. The blade part is a rough blade, and the outer cutting edge located on the radially outer side and the axial base end side further scrapes the inner peripheral surface of the hole cut by the inner peripheral cutting edge. It is said that Here, the inner peripheral side groove wall surface, which is the rake face of the inner peripheral side cutting edge portion, is formed so as to extend in the radial direction of the tool body, and the outer peripheral side cutting edge portion is rearward from the inner peripheral side groove wall surface in the tool rotation direction. Since it is formed so as to be parallel to the inner cutting edge when viewed from the axial tip side, it is formed at the intersecting ridge between the wall surface of the outer circumferential groove that is formed so as to recede one step toward the side and the tip surface of the blade. A positive radial rake angle is given to the outer peripheral side cutting edge portion.

Therefore, according to the drilling tool having the above structure, it is possible to enhance the sharpness of the outer peripheral side cutting edge portion, and burr is generated in the opening portion of the through hole due to the pushing and spreading action of the inner peripheral side cutting edge portion. Even if this is done, it can be scraped off and removed by the outer peripheral cutting edge portion. Further, since the sharpness of the outer peripheral side cutting edge portion can be improved in this way, the surface roughness of the hole to be machined can be improved by the drilling tool having the above-mentioned configuration, and the single step There is also an advantage that it is possible to simultaneously perform roughing and finishing.

[0008]

【Example】

 1 to 4 show an embodiment of the present invention. In these drawings, the tool main body 1 has a shaft-shaped shank 2 to which a shaft-shaped cutting blade member 3 made of a hard material such as cemented carbide is attached by brazing and a blade portion is provided. Has become. A driver portion 2a for mounting the tool body 1 on the spindle end of a machine tool or the like is provided at the base end of the shank 2. In addition, on the outer periphery of the shank 2, four recessed grooves 2b ... Which extend along the axis O of the tool body 1 are formed at equal intervals in the circumferential direction of the tool body 1, and these recessed grooves 2b are formed. A guide pad 4 made of cemented carbide is fixed to each of. Here, the surfaces of the guide pads 4 facing the outer peripheral side are formed into a cylindrical surface centered on the axis O, and the radius of this cylindrical surface is the axis O of the outer peripheral end of the cutting edge described later. It is set to be equal to the rotation diameter D of the circumference.

On the other hand, in the cutting blade member 3, as shown in FIG. 3 as viewed in the direction of the axis O from the tip side of the tool body 1, as shown in FIG. 5 are formed so as to extend parallel to the axis O and symmetrically with respect to each other with the axis O interposed therebetween, and extend from the tip of the cutting blade member 3 to immediately before the shank 2. A cutting edge 8 is formed at the intersection ridge of the groove wall surface 6 of each chip discharge groove 5 that faces the tool rotation direction (counterclockwise direction in FIG. 3) and the tip surface 7 of the cutting blade member 3. Is made. Therefore, also in this embodiment, the groove wall surface 6 is the rake face of the cutting edge 8 and the tip face 7 is the flank face.

The tip surface 7, which is the flank, is formed in a substantially conical surface centered on the axis O, and the tip surface 7 is rearward of the cutting edge 8 in the tool rotating direction. The relief is provided so as to face the base end side in the direction of the axis O as it goes toward the side. Therefore, as shown in FIG. 4, in a side view of the cutting blade member 3, the respective cutting blades 8 and 8 are formed in a mountain shape toward the base end side in the direction of the axis O toward the outer peripheral side of the tool body 1. It In addition, at the tool rotation center portion on the axis O of the tip of the cutting blade member 3, each cutting blade 8 is thinned. Further, in the tool body 1, an oil hole 9 is formed in the shank 2 and the driver portion 2a along the axis O, and the tip end side of the oil hole 9 extends into the cutting blade member 3 and branches, It is opened at the base end of each chip discharge groove 5 and the above-mentioned tip surface 7, and the cutting oil is supplied from this oil hole at the time of processing so that the cutting blade 8 and the work material are cooled. Is aimed at.

In the present embodiment, the groove wall surface 6 is located on the inner side of the tool body 1 in the radial direction and is formed so as to extend in the radial direction including the axis O and the inner peripheral side wall surface 6 a. The outer groove side wall surface 6b is located radially outward of the side groove wall surface 6a. Here, the outer peripheral side groove wall surface 6b is made parallel to the inner peripheral side groove wall surface 6a, and is provided so as to be retracted by a retreat amount H to the rear side in the tool rotation direction. The groove wall surface 6 is formed in a multi-step shape in which one step is recessed on the outside in the radial direction of the tool body 1.

Further, since the groove wall surface 6 is formed in such a multi-step shape, the cutting edge 8 formed at the ridge line intersecting the groove wall surface 6 and the tip surface 7 is also formed by a plurality of cutting edge portions. Will be done. That is, the ridge line intersecting the inner circumferential side wall surface 6a and the tip surface 7 is located inside the cutting edge 8 in the radial direction and extends in the radial direction of the tool body 1 when viewed from the tip side of the tool body 1 in the direction of the axis O. While the inner peripheral side cutting edge portion 8a is formed, on the ridge line portion where the outer peripheral side groove wall surface 6b and the tip surface 8 intersect, on the radial outer side of the inner peripheral side cutting edge portion 8a and on the rear side in the tool rotation direction, An outer peripheral cutting edge portion 8b extending parallel to the inner peripheral cutting edge portion 8a when viewed from the tip side of the tool body 1 in the direction of the axis O is formed. 3 and 4, reference numerals Fa and Fb represent radial lengths of the inner peripheral cutting edge portion 8a and the outer peripheral cutting edge portion 8b, respectively. Further, the reference numeral D indicates the rotation diameter of the outer peripheral end of the cutting edge 8, that is, the outer peripheral end of the outer peripheral side cutting edge portion 8b around the axis O. Therefore, the rotation diameter D is set equal to 2Fa + 2Fb.

Here, the retreat amount of the outer peripheral side cutting edge portion 8b with respect to the inner peripheral side cutting edge portion 8a in the tool rotation direction is set to the retreat amount H of the outer peripheral side groove wall surface 6b with respect to the inner peripheral side groove wall surface 6a as shown in FIG. Will be equal. Further, as described above, the tip surface 7 is provided with a clearance toward the rear side in the tool rotation direction, and the cutting edge 8 is formed in a mountain shape toward the base end side in the axis O direction as it goes radially outward. Therefore, the outer peripheral cutting edge 8b is parallel to the inner peripheral cutting edge 8a in the side view from the direction perpendicular to the groove wall surface 6 and retracts one step toward the proximal side in the axis O direction as shown in FIG. Will be formed.

Further, on the outer periphery of the cutting blade member 3, a margin 10 is formed along the axis O direction behind the outer peripheral groove wall surface 6b of each chip discharge groove 5, 5 in the tool rotation direction. Further, behind the margin 10 in the tool rotation direction, pad portions 11 are formed on the ridges of the chip discharge grooves 5, 5 on the tool rotation direction side, also along the axis O direction. The margins 10 and 10 and the pad portions 11 and 11 are each formed such that the outer peripheral surfaces thereof are formed into a cylindrical surface centered on the axis O, and they are alternately arranged substantially equally in the circumferential direction of the tool body 1. It is formed so as to be arranged at intervals.

In the drilling tool having such a configuration, in the cutting blade 8, the outer peripheral side cutting edge portion 8b is more radially outward than the inner peripheral side cutting edge portion 8a, and is on the rear side in the tool rotation direction and in the axis O direction. Since it is located at the base end side, when drilling, the inner cutting edge 8a first cuts the work material to form a hole of radius Fa, and immediately thereafter, the outer cutting edge 8b cuts this hole. The cutting is performed by cutting the inner circumference with a cutting amount Fb to form a hole having a radius Fa + Fb, that is, a diameter D. That is, after the inner peripheral side cutting edge portion 8a precedes as a rough blade, the outer peripheral side cutting edge portion 8b forms a finishing blade into a hole having a predetermined diameter. Here, in the inner peripheral side cutting edge portion 8a, since the inner peripheral side groove wall surface 6a is formed to extend in the radial direction including the axis O, both the axial rake angle and the radial rake angle are 0. Set to °. On the other hand, regarding the outer peripheral side cutting edge portion 8b, since the outer peripheral side groove wall surface 6b is parallel to the inner peripheral side groove wall surface 6a, the axial rake angle is also set to 0 °, but the outer peripheral side groove wall surface 6b is Since it is arranged at a position retracted rearward in the tool rotation direction from the circumferential groove wall surface 6a, a positive rake angle θ is given in the radial direction as shown in FIG.

Therefore, in the drilling tool having the above-described configuration, the inner peripheral side cutting edge portion 8a among these cutting edge portions 8a, 8b secures a cutting edge angle to enhance the strength of the cutting edge and is compatible with high feed. As a result, it is possible to maintain the same machining efficiency as the conventional one, while it is possible to give the cutting edge a sharp cutting edge in the outer peripheral side cutting edge portion 8b which is a finishing blade. Thus, for example, when forming a through hole in a work material, even if a burr is generated in the opening of the hole due to the pushing and spreading action of the tool feed, the outer peripheral cutting edge portion has a sharp cutting edge. Since the burr can be scraped off when the hole penetrates by 8b, it becomes possible to perform high-quality drilling without burrs in a single process with the above-mentioned drilling tool, which is the same as the conventional method. It is not necessary to perform deburring after forming a through hole in the hole, which simplifies the machining process and improves machining efficiency.

Further, since the cutting edge portion 8b on the outer peripheral side, which finally forms the inner peripheral surface of the hole as the finishing blade, is provided with the sharp cutting edge as described above, the drilling tool having the above-described configuration can form a hole. It is possible to improve the surface roughness. Therefore, for example, after drilling a hole with a diameter slightly smaller than the required diameter with a drill as in conventional drilling, the hole is subjected to finishing with a reamer to finish it to a specified diameter and surface roughness. On the other hand, it is possible to finish a hole with a predetermined diameter with high surface roughness in a single process. Therefore, according to the drilling tool having the above structure, it is possible to promote simplification of the machining process and improvement of machining efficiency.

Further, in the drilling tool having the above-mentioned configuration, since the cutting edge 8 is composed of the two cutting edge portions 8a and 8b, the chips generated during the drilling process are the inner cutting edge portion 8a. The chips generated by the above and the chips generated by the outer peripheral side cutting edge portion 8a are divided into two and generated. Therefore, the drilling tool described above also has an advantage that it is possible to effectively prevent clogging of the chips and perform smooth drilling. Moreover, among the cutting blades 8a and 8b, the chips generated by the outer peripheral side cutting edge 8b collide with the step portion between the inner peripheral side wall surface 6a and the outer peripheral side wall surface 6b and are curled smaller and discharged. As a result, it becomes possible to prevent chip clogging more effectively.

By the way, as shown in FIG. 3, the positive radial rake angle θ given to the inner cutting edge 8b is the radial length Fa of the inner cutting edge 8a and the outer cutting edge 8a. The sum of the radial length Fb of the portion 8b Fa + Fb (1/2 of the rotation diameter D of the outer peripheral end of the cutting edge 8) and the tool rotation direction from the inner peripheral cutting edge 8a to the outer peripheral cutting edge 8b Although it is determined by the backward movement amount H, it is desirable that the radial rake angle θ be set within the range of 3 ° to 20 °. This is because if the radial rake angle θ is too small, the above-mentioned effect due to the rake angle being set to the regular angle side may not be fully achieved. This is because the cutting edge angle of 8B becomes small and chipping or chipping may occur.

Further, the retreat amount H is preferably set within the range of 0.2M to 0.9M with respect to the width M of the margin 10, although it depends on the size of the tool and the like. This is because if the retreat amount H is too small, the radial rake angle θ also becomes small and the above effect cannot be obtained, while if the retreat amount H is too large, the thickness of the margin 10 becomes too small and the blade portion becomes too small. This is because the straightness of the cutting blade member 3 may be impaired. However, the margin width M referred to here is, as shown in FIG. 3, a rotation locus of the outer peripheral edge of the outer peripheral cutting edge portion 8b around the axis O and a radially extended line of the inner peripheral cutting edge portion 8a. The distance from the intersection point P to the edge of the margin 10 on the rear side in the tool rotation direction. Further, the radial length Fb of the outer peripheral side cutting edge portion 8b is set within the range of 0.05D to 0.25D with respect to the rotational diameter D of the outer peripheral end about the axis O rotation. I want it. This is because if the length Fb is too small, the deburring effect and the chip discharge performance may not be sufficiently improved, and if the length Fb is too large, the inner cutting edge portion 8a, which is a rough blade, may not be effective. This is because there is a risk that it will become shorter and it will not be possible to apply high feed.

[0021]

[Effect of device]

 As described above, in the drilling tool of the present invention, the groove wall surface of the chip discharge groove is formed in a multi-step shape that recedes rearward in the tool rotation direction as it goes outward in the radial direction of the tool body, and thereby is formed at the tool tip. By forming the cutting edge with a plurality of cutting edge portions, it is possible to give a positive radial rake angle to the outer peripheral cutting edge portion. This makes it possible to scrape off and remove burrs in the openings when forming through-holes, improve the surface accuracy of the holes, and enable high-quality drilling in a single machining step. As a result, the processing steps can be simplified and the processing efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 2 is a ZZ sectional view in FIG.

3 is an enlarged view of the embodiment shown in FIG. 1 as seen from the direction of the axis O from the tip side.

FIG. 4 is a side view as viewed in the Y direction in FIG.

[Explanation of symbols]

1 Tool body 2 Shank 3 Cutting edge member 5 Chip discharging groove 6 Groove wall surface (rake surface) of the chip discharging groove 5 that faces the tool rotation direction 6a Inner circumferential groove wall surface 6b Outer circumferential groove wall surface 7 Cutting edge member 3 tip surface (tip clearance) 8) Cutting edge 8a Inner peripheral side cutting edge section 8b Outer peripheral side cutting edge section 10 Margin O Rotation axis of the tool body 1 Rotation diameter around the axis O of the outer peripheral end of the cutting edge 8 Fa Inner side cutting edge section 8a Radial length Fb Radial length of outer peripheral cutting edge 8b H Retraction of outer peripheral groove wall surface 8b M Margin width θ Radial rake angle of outer peripheral cutting edge 8b

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Haruo Kawase, 1528 Nakanishida, Yokoi, Kobe, Anha-gun, Gifu Prefecture, Gifu Works, Mitsubishi Materials Corporation (72) Takashi Kubota, Yokoi, Kobe, Anha-gun, Gifu Prefecture 1528 Nakashinta, Gifu Works, Mitsubishi Materials Corporation (72) Inventor Katsunori Matsumoto, Kobe, Anpachi-gun, Gifu Prefecture, Yokoi, 1528 Nakashinta, Gifu Works, Mitsubishi Materials Corporation

Claims (1)

[Scope of utility model registration request] 1. A blade portion is provided at a tip of a tool body rotated about an axis, and at least one chip discharging groove is formed on an outer periphery of the blade portion along the axial direction,
In a drilling tool in which a cutting edge is formed at a ridge line intersecting with a wall surface of the chip discharging groove facing the tool rotation direction and a tip surface of the blade portion, the groove wall surface is a radial inner side of the tool body. Formed in a multi-step manner including an inner peripheral side wall surface extending in the radial direction and an outer peripheral side wall surface located outside of the radial direction and retracted one step backward in the tool rotation direction with respect to the inner peripheral side wall surface. At the same time, the cutting edge is also formed at the ridge line portion where the inner circumferential groove wall surface and the tip end surface intersect with each other, is located inside the radial direction, and has the diameter when viewed in the axial direction from the tip end side of the tool body. Formed in the inner peripheral side cutting edge portion, the outer peripheral side groove wall surface and the front edge surface intersecting ridge line portion, the radially outer side of the inner peripheral side cutting edge portion, and the tool rotation direction rear side, And it is located on the base end side in the axial direction, and the axis line from the tip side of the tool body. A drilling tool, comprising: a plurality of cutting edge portions provided with an outer peripheral cutting edge portion extending parallel to the inner peripheral cutting edge portion when viewed in a direction.