JP3149696B2 - Gun Reamer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gun reamer for expanding a pilot hole formed by a drill or the like to a predetermined size, particularly in a finishing step of deep hole processing.

[0002]

2. Description of the Related Art As this kind of gun reamer, for example, the one shown in FIGS. 5 and 6 is generally known. This gun reamer has a configuration in which a cutting edge tip 2 made of a hard material such as a cemented carbide is attached to the tip of a tool body 1 having an axial shape by brazing or the like, and a blade portion 3 is provided. A chip discharge groove 4 is formed on the outer periphery of the blade portion 3 along the direction of the rotation axis O of the tool body 1, and the tool rotation direction (the direction of the white arrow in the drawing) of the chip discharge groove 4 is changed. A cutting edge 5 is formed on the ridge portion on the tip side and the outer peripheral side of the facing wall surface 4A. In the example shown in the figure, an ultra-hard sintered body 6A mainly composed of diamond or CBN (cubic boron nitride) and a high-hardness The layered sintered body 6 formed by laminating the sintered body 6B is joined so that the portion of the super-hardened sintered body 6A is oriented in the tool rotation direction. It is formed in the portion of the ultra-high hardness sintered body 6A.

On the other hand, on the outer periphery of the blade portion 3,
A margin portion 7 is formed so as to extend rearward in the tool rotation direction of the chip discharge groove 4 along the axis, and a bearing portion 8 is formed as a guide portion behind the margin portion 7 in the tool rotation direction. . Further, on the rear side of the bearing portion 8 in the tool rotation direction, a pad portion 9 is formed as a second guide portion along the ridge portion of the chip discharge groove 4 on the tool rotation direction side. In addition, between the margin portion 7 and the bearing portion 8 and the bearing portion 8
Between the pad portion 9 and the margin portion 7, there is an outer peripheral flank 10 that is slightly recessed toward the inner peripheral side of the tool and is provided with a clearance with respect to the margin portion 7, the bearing portion 8, and the pad portion 9.

In such a gun reamer, the outer peripheral surfaces of the margin portion 7, the bearing portion 8, and the pad portion 9 are:
It is formed in a cylindrical shape with a radius equal to the outer diameter of the cutting edge 5 about the axis O. Then, the inner periphery of the machined hole cut by the cutting blade 5 is rubbed by the margin portion 7 to obtain a smooth inner peripheral surface, and the bearing portion 8 and the pad portion 9 slide on the inner peripheral surface of the machined hole. While the blade portion 3 moves forward, the blade portion 3 is guided so that the axis O of the tool main body 1 coincides with the center axis of the machining hole. Body 1
The straightness of the hole is ensured, and a highly accurate hole is formed.

[0005]

When a hole is formed in a work piece having a high hardness such as a sintered alloy by using such a gun reamer, the work piece is cut off by the cutting blade 5. It is known that the inner periphery of the machined hole slightly expands due to elastic deformation, and the inner periphery of the enlarged hole instantaneously contracts immediately after the cutting edge 5 passes. Then, since the bearing portion 8 and the pad portion 9 come into sliding contact with the inner periphery, the bearing portion 8 and the pad portion 9 are tightened into the inner peripheral surface of the processing hole and rotated while being pressed. As a result, there arises a problem that the rotational driving force increases due to an increase in frictional resistance, and that the bearing portion 8 and the pad portion 9 are significantly worn. In addition, fine chips generated by cutting by the cutting blade 5 may be caught between the bearing portion 8 or the pad portion 9 and the inner periphery of the processing hole, thereby deteriorating the processing surface roughness.

Here, not only the processing by the gun reamer but also the drilling including drilling, for the purpose of lubricating the cutting part 3 and the processing hole, discharging chips, or cooling the cutting blade 5. Generally, processing is often performed while supplying a cutting oil to the blade portion 3 side. However, in the gun reamer, as described above, the bearing 8 and the pad 9
Since the cutting is performed while sliding on the inner periphery of the machining hole as a guide portion, it is difficult to sufficiently feed the supplied cutting fluid between the bearing portion 8 or the pad portion 9 and the inner periphery of the machining hole. Become. Moreover, the margin portion 7 and the bearing portion 8
And between the bearing portion 8 and the pad portion 9, only a very shallow and narrow gap is defined between the outer peripheral flank surfaces 10 and 10 of the blade portion 3 and the inner peripheral surface of the machining hole. However, since the amount of the cutting fluid that can be accommodated in such a gap becomes extremely small, it is even more difficult to feed a sufficient amount of the cutting fluid between the bearing portion 8 or the pad portion 9 and the inner periphery of the machining hole. It has to be difficult.

The present invention has been made under such a background, and is capable of sufficiently supplying a cutting oil to a guide portion for guiding a blade portion, thereby effectively lubricating the guide portion and removing chips. The aim is to provide a gun reamer that can encourage emissions.

[0008]

In order to solve the above-mentioned problems and to achieve such an object, the present invention provides a tool body which is provided at a tip end of a tool body which is rotated around an axis. At least one chip discharge groove is formed along the axial direction on the outer periphery of the chip, and a cutting edge is formed on a tip side of a wall surface of the chip discharge groove facing the tool rotation direction and a ridge line portion on a tool outer peripheral side. In the gun reamer, at least one guide portion for guiding the blade portion is formed on the outer periphery of the blade portion, and between the guide portion and the cutting blade or between the guide portions is defined as an outer peripheral flank. On the boundary ridge portion between the side wall portion on the tool rotation direction side of the guide portion and the outer peripheral flank surface, a concave groove portion depressed on the tool inner peripheral side with respect to the outer peripheral flank surface is formed along the boundary ridge line portion. It is characterized by the following.

[0009]

According to the gun reamer having such a configuration, the guide portion provided on the outer periphery of the blade portion, that is, the side wall portion of the bearing portion or the pad portion on the tool rotation direction side is adjacent to the guide portion on the tool rotation direction side. Since the concave groove portion is formed at the boundary ridge portion between the outer peripheral flank to be formed, it is possible to increase the capacity of the gap defined between the outer peripheral flank and the inner periphery of the processing hole during processing. The supply amount of the cutting fluid to the guide portion can also be increased. Further, since the concave groove portion is formed on the rear side in the tool rotation direction of the gap between the outer peripheral flank surface and the inner peripheral surface of the machining hole, that is, the groove portion is formed immediately before the tool rotation direction with respect to the guide portion. More cutting fluid can be supplied and stored immediately before the guide, and this cutting fluid is sent between the guide and the inner periphery of the machining hole with the rotation of the tool body, so that cutting can be performed efficiently. Oil supply can be performed. And, by increasing the capacity of the gap in which these cutting fluids are accommodated and enabling efficient supply, it is possible to reliably and sufficiently feed the cutting fluid between the guide portion and the inner periphery of the processing hole, In addition, it is possible to quickly discharge chips generated during cutting.

Here, in order to prevent the stagnation of the cutting oil in the groove and to supply the cutting oil more reliably and efficiently to the guide portion, the bottom of the groove should be aligned with the axis of the tool body. It is desirable that the cross section be formed in an arc shape in a cross section orthogonal to the cross section. When such a configuration is employed, it is desirable that the radius of the arc formed by the bottom surface of the concave groove portion in a cross section orthogonal to the axis is set in the range of 0.5 mm to 2.0 mm. This is because when the radius of the arc is smaller than 0.5 mm, the increase in the cutting oil storage capacity due to the concave groove portion is not sufficiently expected, and
There is a possibility that the cutting oil may accumulate at the bottom of the concave groove portion. Conversely, if it is larger than 2.0 mm, the rigidity of the blade portion is impaired, depending on the size of the blade portion itself of the tool. This is because there is a fear. Further, in order to provide the cutting blade with high strength and wear resistance, an ultra-high-hardness sintered body and a high-hardness sintered body are laminated on the corner on the outer peripheral end of the wall surface of the chip discharge groove. It is desirable that the layered sintered body is joined with the part of the ultra-high hardness sintered body facing the tool rotation direction side, and the cutting edge is formed on the ultra-high hardness sintered body.

[0011]

1 to 4 show an embodiment of the present invention. In these figures, a tool body 11 has a cylindrical cutting blade tip 12 made of a hard material such as cemented carbide, which is coaxially joined to the shank by brazing or the like at the tip of an axial shank (not shown). A portion 13 is provided. At the base end of the shank, a driver (not shown) for fixing the tool body 11 to the spindle end of the machine tool is provided, and the tool body 11 rotates around its axis O with the rotation of the spindle end. It is made to be rotated. On the outer periphery of the blade portion 13, a single chip discharge groove 14 having a substantially V-shaped cross section orthogonal to the axis O and opening to the outer peripheral side is formed in parallel with the axis O from the tip of the blade portion 13. A cutting edge 15 is formed on the outer peripheral edge of the tip of the wall surface 14A of the chip discharge groove 14 which faces the tool rotation direction (the direction of the white arrow in the figure). .

In this embodiment, a 1/4 circular concave portion 14B is formed in the corner on the outer peripheral side of the front end of the wall surface 14A so as to be recessed by one step from the wall surface 14A, and diamond or CBN is formed in the concave portion 14B. A layered sintered body 16 formed by laminating a super-hardened sintered body 16A mainly composed of a super-hardened sintered body 16B such as a cemented carbide is rotated by a tool rotating tool. Hard sintered body 16
The part B is joined by brazing.
Here, the surface 16a facing the tool rotation direction and the surface 16b facing the tool outer peripheral side of the portion of the ultra-high hardness sintered body 16A are:
The cutting edge 15A is formed flush with each of the wall surface 14A and an outer peripheral surface of a margin portion described later.
Are formed on the edge of the surface 16a in the portion of the ultra-hard sintered body 16A of the layered sintered body 16.

On the other hand, the chip discharge groove 1
4, a margin portion 17 is formed so as to extend rearward in the tool rotation direction and extend parallel to the direction of the axis O along a portion of the cutting edge 15 on the outer peripheral side of the tool. This margin part 17
Has an outer peripheral surface formed into a cylindrical surface having the same diameter as the outer diameter of the cutting edge 15 coaxially with the axis O, and is not so-called double-cut. Also, this margin part 1
7, a bearing portion 18 is formed as a guide portion in the present embodiment behind the tool rotation direction. Here, the bearing portion 18 is also formed so that its outer peripheral surface is coaxial with the axis O and has a cylindrical surface having a diameter equal to the outer diameter of the cutting blade 15 and extends in a direction parallel to the axis O. ing.

In this embodiment, the bearing 18
Is composed of two bearing portions 18A and 18B arranged at an interval in the circumferential direction of the blade portion 13, of which a second bearing portion 18B on the rear side in the tool rotation direction.
Are arranged so as to be located on substantially the opposite side of the margin portion 18 with respect to the axis O in the circumferential direction of the blade portion 13, and the first bearing portion 18A is provided with the margin portion 17 and the second bearing portion 18B. Are arranged so as to be located substantially in the middle of the. Further, the first and second bearing portions 18A and 18B are formed so that their widths are substantially equal to each other in the circumferential direction of the blade portion 13, and are arranged at a width interval substantially equal to this width. I have.

Further, a pad portion 19 is formed further rearward of the second bearing portion 18B in the tool rotation direction along the ridge portion of the chip discharge groove 14 on the tool rotation direction side. In the second guide portion. Similarly to the margin portion 17 and the bearing portion 18, the outer peripheral surface of the pad portion 19 is formed in a cylindrical surface having the same diameter as the outer diameter of the cutting blade 15 centered on the axis O,
It is formed so as to extend along the axis O direction. Further, the pad portion 19 is disposed so as to be located substantially opposite to the first bearing portion 18A with respect to the axis O in the circumferential direction of the blade portion 3, and has a width in the circumferential direction of the first bearing portion 18A. First, the width is set to be smaller than the width of the second bearing portions 18A, 18B and substantially equal to the width of the margin portion 17.

By forming the margin portion 17, the first and second bearing portions 18A and 18B, and the pad portion 19 on the outer periphery of the blade portion 13 in this manner, the margin portion 17 and the first bearing portion adjacent to each other are formed. 18A, between the first and second bearing portions 18A and 18B, and between the second bearing portion 18B and the pad portion 19, relative to the rotation trajectory around the axis O of the cutting edge 15 on the tool outer peripheral side. As a result, a recessed portion is formed on the inner peripheral side of the tool, and the outer peripheral surface of the blade portion 13 at this portion is formed on the outer peripheral flank 20A, 20A, respectively.
B, 20C. In the present embodiment, the outer peripheral flank surfaces 20A, 20B, and 20C, and the first and second bearing portions 18A, 18A, 20A, 20B, and 20C are arranged so as to rise toward the outer peripheral side of the tool with respect to the outer peripheral flank surfaces 20A, 20B, and 20C. 18
B and the side wall portion 18 on the tool rotation direction side of the pad portion 19
a, 18b, and 19a, and grooves 21A, 21B, and 21C recessed toward the tool inner periphery with respect to the outer peripheral flank surfaces 20A, 20B, and 20C, respectively, along the ridge line in the direction of the axis O along the ridge lines. It is formed so as to extend in parallel.

These concave grooves 21A, 21B, 21C
In any of the cross sections orthogonal to the axis O, the bottom surface 21a has an arc shape with a radius R as shown in FIG.
A, 18B and the side wall portions 18a of the pad portion 19,
It is formed so as to be smoothly connected to 18b and 19a. Here, it is desirable that the radius R of the circular arc that the bottom surface 21a exhibits in a cross section orthogonal to the axis O be set in the range of 0.5 mm to 2.0 mm. In addition, the side wall portion 18
Reference numerals a, 18b, and 19a are formed on flat surfaces that are slightly inclined toward the rear side in the tool rotation direction toward the outer peripheral side of the tool.

In this embodiment, the cutting edge 15
Is set so as to be slightly larger than a desired processing diameter by the gun reamer. Further, as shown in FIG. 2, the cutting edge portion 15a on the tip end side of the cutting edge 15 is chamfered in a direction oblique to the axis O at an inclination angle θ toward the tool inner peripheral side toward the tip end side. Further, the cutting edge 15a is provided with a honing 22 in a direction perpendicular to the surface 16a of the layered sintered body 16 which faces the tool rotation direction.
Is given. Here, the honing 22, the width L ₁ in a direction perpendicular to the surface 16a is 0.05mm~
Are those made is set in a range of 0.2 mm, the width L ₂ in the radial direction with respect to the axis O of the cutting edge 15a of the front end side of the cutting edge 15 of the honing 22 is subjected, processing by the Ganrima T × 0.
It is set in the range of 5 to T × 1.5. Further, the inclination angle θ of the cutting edge portion 15a with respect to the axis O is 10 ° to 40 °.
It is desirable to set the angle in the range of 30 °, and in this embodiment, it is set to 30 °.

In the gun reamer having such a configuration, the first and second bearing portions 18A, 18 formed as guide portions are provided.
8B and the side wall portion 18 on the tool rotation direction side of the pad portion 19
Since grooves 21A, 21B, and 21C are formed at the boundary ridges between the outer peripheral flank surfaces 20A, 20B, and 20C, respectively, which are disposed in front of the a, 18b, and 19a in the tool rotation direction, machining by the gun reamer is performed. At times, the capacity of each gap defined between the outer peripheral flank surfaces 20A, 20B, 20C and the inner peripheral surface of the machining hole can be increased, so that more cutting oil can be supplied to the gap. Become. Moreover, each of the grooves 21A, 21B, 21C is formed on the rear side in the tool rotation direction of each of the gaps, that is, formed immediately before the bearings 18A, 18B and the pad 19 in the tool rotation direction. Therefore, the cutting oil supplied to the gap is not
8A and 18B and more immediately before the pad portion 19 are held.

The bearings 18A, 18A,
18B and grooves 21A, 21 immediately before pad portion 19
B, a large amount of cutting fluid held in 21C is applied to the tool body 1
According to the gun reamer having the above-described configuration, the guides are used as these guides because they are fed between the bearings 18A and 18B and the pad 19 at the rear of the tool rotation direction and the inner periphery of the machining hole along with the rotation of 1. Bearing part 18 of
It is possible to efficiently and sufficiently supply the cutting fluid between the A, 18B and the pad portion 19 and the inner periphery of the machining hole, and thereby, the bearing portions 18A and 18B and the pad portion 19 and the inner periphery of the machining hole can be provided. Is effectively performed, the frictional resistance between the two is reduced to reduce the rotational driving force of the tool body 11, or the bearing portions 18A, 18
B and the abrasion of the pad portion 19 can be suppressed. In addition, since chips can be quickly discharged by a large amount of cutting oil supplied to the gap, such chips can be removed from the bearing portions 18A and 18B and the pad portion 19A.
It is possible to prevent a situation in which the machining surface roughness is degraded by being caught between the workpiece and the machining hole.

In this embodiment, the grooves 21A, 2A are used.
The bottom surface 21a of each of the grooves 1B and 21C has an arc shape in a cross section orthogonal to the axis O.
Prevent stagnation of cutting fluid held in 1B, 21C,
With the rotation of the tool body 11, it becomes possible to quickly supply the cutting oil between the bearing portions 18A and 18B and the pad portion 19 and the inner periphery of the machining hole. Further, it is possible to prevent chips generated during processing from clogging the concave grooves 21A, 21B, 21C. In addition, the bottom surface 21a of the concave grooves 21A, 21B, 21C is thus
In the case where the cross section is formed in an arc shape, if the radius R of the arc is too small, there is a possibility that the above-described effects of preventing the stagnation of the cutting fluid and clogging of the chips may not be sufficiently obtained. On the other hand, if the radius R of the arc is too large, the concave grooves 21A, 21B,
The depth of 21C itself must be formed to some extent, and when the outer diameter of the blade portion 13 is small, the rigidity of the blade portion 13 may be impaired. For this reason, it is desirable that the radius R of the arc formed by the cross section of the bottom surface 21a of the concave grooves 21A, 21B, 21C is set within the range of 0.5 mm to 2.0 mm as described above.

In addition, in the present embodiment, the ultra-high hardness sintered body 16A and the high hardness sintered body 16B are provided at the corners on the outer peripheral end of the wall surface 14A of the chip discharge groove 14 facing the tool rotation direction.
Are laminated, and the cutting edge 15 is formed in a portion of a super-hard sinter 16A mainly composed of diamond or CBN. For this reason, in the present embodiment, since the cutting blade 15 is provided with high strength and wear resistance, it is possible to prevent the cutting blade 15 itself from being worn or chipped, and as described above, the bearing portion 18A , 18B and the pad portion 19 are suppressed, and the tool life can be further extended.

Further, in this embodiment, the bearing portion 18 is composed of first and second two bearing portions 18A and 18B, and these bearing portions 18A and 18B are provided.
Between B, the outer peripheral flank 20B is provided to provide clearance to the inner periphery of the machined hole. Therefore, according to the present embodiment, contact between the bearing portion 18 and the inner periphery of the machined hole is reduced. The frictional resistance can be further reduced and the rotational driving force of the tool body 11 can be further reduced. On the other hand, the second bearing portion 18B is arranged on the substantially opposite side of the margin portion 17 connected to the cutting edge 15 with the axis O interposed therebetween, and the first bearing portion 18A and the pad portion 19 are also aligned with the axis O. Since the bearings 18 are arranged on the substantially opposite sides with respect to each other, the bearing 18 is slidably in contact with the inner periphery of the machined hole in this embodiment, although the bearing 18 is composed of the two bearings 18A and 18B as described above. The balance of the margin portion 17 and each guide portion in the tool circumferential direction is not lost, and the deflection of the blade portion 13 during machining can be suppressed to perform machining with high accuracy.

When a pilot hole formed in a workpiece such as a sintered alloy is processed by a gun reamer, when the inner periphery of the processing hole is cut off by the cutting blade 15, the processing is performed by elastic deformation of the workpiece. As described above, the problem of the blade portion being tightened due to the diameter of the hole being enlarged and the diameter being reduced instantaneously thereafter is caused as described above. Due to the contraction of the hole, there is also a problem that the inner diameter of the hole formed in the gun reamer becomes smaller than a desired processing diameter. In addition, due to the tightening due to the contraction of the machining hole, the initial wear of the cutting blade, particularly at the tip end portion, increases, which may also cause the inside diameter of the machining hole to become smaller than a desired diameter.

On the other hand, in the present embodiment, the outer diameter of the cutting blade 15 is set to be slightly larger than the desired processing diameter by the gun reamer. It is designed so that a desired processing diameter can be obtained in this state. In order to obtain a desired processing diameter with the processing hole contracted in this way,
The outer diameter of the cutting edge 15 is 1.0001 with respect to the desired processing diameter D.
It is desirable to set about × D to 1.002 × D,
Specifically, the cutting edge 15 is set at 0.
It is desirable to form it so as to be located at about 001 mm to 0.010 mm on the outer peripheral side of the tool.

In addition, in this embodiment, the cutting blade 1
5 is chamfered at an inclination angle θ with respect to the axis O, and the cutting edge portion 15a has a face that becomes a rake face in the tool rotation direction of the layered sintered body 16. 16
A honing 22 is applied vertically to a. Therefore, on the tip side of the cutting edge 15, the cutting edge portion 15a first bites into the work material, but a portion corresponding to the initial wear of the cutting edge portion 15a is previously cut off by the honing 22. It has such a shape. For this reason, according to the present embodiment, even if initial wear occurs on the tip side of the cutting edge 15 due to contraction of the processing hole, it is possible to stabilize this quickly and suppress the progress of subsequent wear. This also makes it possible to suppress a reduction in the processing diameter due to the gun reamer.

[0027] In this embodiment 0.05mm width L ₁ in a direction perpendicular to the surface 16a of the honing 22
Although the ～0.2Mm, which, when the width L ₁ is small enough below this range, the effect of suppressing the wear described above there may not be successful enough, if large enough above this range the contrary, Since no relief is given to the honing 22, there is a possibility that the cutting resistance increases. Also, the width L ₂ in the radial direction of the cutting edge portion 15a in the present embodiment, although a 0.5 × T~1.5 × T relative allowance T taken in working bore circumference, which is the width L _{If 2} is less than 0.5 × T, the biting of the cutting edge portion 15a into the inner periphery of the processing hole becomes unstable, and conversely, even if it is larger than 1.5 × T, the portion on the inner peripheral side is Is not provided, so the cutting edge 15
This is because unnecessary labor is required for forming the a and the honing 22. Furthermore, in the present embodiment, the inclination angle θ of the cutting edge portion 15a with respect to the axis O is set to 30 °. However, if the inclination angle θ is too small, the cutting edge portion 15a becomes longer, and accordingly, the honing 22 becomes longer. Again, the cutting resistance is increased, and conversely, if the inclination angle θ is small, the cutting edge portion 15a will suddenly bite into the inner periphery of the machined hole, and the above-described wear suppressing effect may be insufficient. For this reason, the inclination angle θ of the cutting edge 15a is 10 ° to 40 ° as described above.
It is desirable to set in the range.

[0028]

As described above, according to the present invention, the guide portion, such as a bearing portion or a pad portion, provided on the outer periphery of the blade portion is arranged on the tool rotation direction side wall and on the tool rotation direction side. By forming a concave groove portion at the boundary ridge line between the outer peripheral flank and the outer peripheral flank, the capacity of the gap defined between the outer peripheral flank and the inner periphery of the processing hole during processing is increased, so that more cutting can be performed. The oil agent can be supplied and stored just before the guide portion in the tool rotation direction. With the rotation of the tool body, the cutting fluid is efficiently and sufficiently fed between the guide portion and the inner periphery of the processing hole to reduce the friction between the two. However, even when the rotation occurs, it is possible to prevent a situation in which the tool rotation driving force is increased or the guide portion is worn. Also,
In this way, a large amount of cutting oil can be supplied,
Chips generated at the time of cutting can be quickly discharged, and it is also possible to prevent a situation in which the machining surface roughness is deteriorated due to such chipping.

[Brief description of the drawings]

FIG. 1 is a front view of a blade portion 13 showing one embodiment of the present invention, as viewed from a tip end side.

FIG. 2 is a side view of the distal end of the blade portion 13 of the embodiment shown in FIG.

FIG. 3 is an enlarged cross-sectional view orthogonal to the axis O around the concave groove portion 21 of the embodiment shown in FIG.

FIG. 4 is an enlarged view in the X direction in FIG. 2;

FIG. 5 is a front view of a conventional gun reamer viewed from a tip end side of a blade portion 3;

FIG. 6 is a side view of the distal end of the conventional blade portion 3 shown in FIG.

[Explanation of symbols]

1,11 tool body 3,13 blade 4,14 chip discharge groove 5,15 cutting blade 15a cutting blade 15 at the tip end of cutting blade 15,6 layered sintered body 6A, 16A ultra-high hardness sintered body 7, 17 Margin part 8, 18 (18A, 18B) Bearing part (guide part) 9, 19 Pad part (guide part) 18a, 18b, 19a Bearing part 18A, 18B
And the side wall portion 10, 20A, 20B, 20C of the pad portion 19 on the tool rotation direction outer peripheral flank surface 21A, 21B, 21C concave groove portion 22 honing of the cutting edge portion 15a O the rotation axis R of the tool body 11 the bottom surface 21a of the concave groove portion 21 angle of inclination relative to the axis O of the radial width θ cutting edge 15a relative to the axis O of but a width L ₂ cutting edge 15a of the form arc having a radius L ₁ honing 22

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-170640 (JP, A) Japanese Utility Model 62-10026 (JP, Y2) Japanese Utility Model Application 63-12891 (JP, Y2) (58) Field (Int. Cl. ⁷ , DB name) B23D 77/00

Claims (4)

(57) [Claims] 1. A blade is provided at a tip of a tool body rotated around an axis, and at least one chip discharge groove is formed on an outer periphery of the blade along the axial direction.
In a gun reamer in which a cutting edge is formed on a tip side of a wall surface of the chip discharge groove facing the tool rotation direction and a ridge line portion on a tool outer peripheral side, at least one guide for guiding the blade portion is provided on an outer periphery of the blade portion. A guide portion is formed, and an outer peripheral flank is formed between the guide portion and the cutting edge or between the guide portions, and a side wall portion of the guide portion on the tool rotation direction side and the outer peripheral flank are formed. A gun reamer characterized in that a concave ridge portion depressed on the inner peripheral side of the tool with respect to the outer peripheral flank surface is formed along a boundary ridge line portion with the surface. 2. The gun reamer according to claim 1, wherein a bottom surface of the concave groove portion is formed to have an arc shape in a cross section orthogonal to the axis. 3. The gun reamer according to claim 2, wherein a radius of the arc is set in a range of 0.5 mm to 2.0 mm. 4. A layered sintered body obtained by laminating an ultra-hard sintered body and a high-hardness sintered body is provided at a corner on the outer peripheral end of the wall surface of the chip discharge groove. 2. The joined body is joined so that a portion of the joined body is directed to a tool rotation direction side, and the cutting edge is formed on the ultra-high hardness sintered body.
A gun reamer according to claim 3.