JPH08323541A - Reamer with chip breaker - Google Patents

Abstract

PURPOSE: To secure a reamer with a chip breaker easy in regrinding work and long-lived in service life. CONSTITUTION: Both first and second main cutting edges 84 and 86 and both first and second sub cutting edges 88 and 90 are formed in the edge of a cutting face 80 of a reamer cutting part 78. The first and second sub cutting edges 88 and 90 are formed in parallel with each other in the axial direction, while the first and second main cutting edges 84 and 86 are formed into being inclined to the former. A chip breaker 94 consisting of a breaker groover is formed in the cutting face 80 in parallel with the first and second sub cutting edges 88 and 90, and chips to be produced at the time of cutting a workpiece are cut into small pieces, or into being spirally curved, thereby making their discharge easy. At the time of wear in the main cutting edges 84 and 86, the main cutting edges 84 and 86 are merely reground, whereby a slight part of the sub cutting edges 88, 90 adjacent to the main cutting edges 84 and 86 is therefore removed. With this grinding operation, the chip breaker 94 receives no effect, so regrinding is unnecessary as in the past.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reamer, and more particularly to extending the life of a reamer with a chip breaker.

[0002]

2. Description of the Related Art A reamer is a cutting tool used to accurately finish a pre-drilled hole and at the same time obtain a smooth finished surface. The reamer has a body blade axially extending from a shank. Grooves and lands extending in a direction having an axial component are provided. There are a straight blade reamer in which the groove and the land are parallel to the axial direction, and a twisted blade reamer extending in a direction having both the axial direction and the circumferential direction, but in both cases, the groove and the land are Will extend in a direction having an axial component. In addition, a plurality of grooves and lands are often provided, but some such as a gun reamer are provided.

The land has a rake face forming a groove side surface and a margin intersecting with the rake face, and a cutting edge is formed by a line of intersection between the rake face and the margin. Since the reamer cost is usually small, the reamer is usually not equipped with a chip breaker. However, in recent years, the reamer cost may be considerably increased, and in this case, a chip breaker is used to make chips easier to remove by cutting them into short pieces or spirally winding them. Forming began to take place. The tip of the reamer blade is often chamfered to form a chamfer, and if the reamer allowance is large, chips are generated mainly from the main cutting edge of this chamfer, so A chip breaker was formed by forming a groove or step parallel to the main cutting edge of the bite part. If a breaker groove is formed, a rake angle is generated and the sharpness is improved.

[0004]

However, in the case where the breaker groove is formed parallel to the main cutting edge of the chamfered portion, the portion where the breaker groove is formed when the main cutting edge is worn and regrinded It is necessary to remove the whole by grinding to form the main cutting edge and the breaker groove again, which requires a lot of time for re-grinding and shortens the life of the reamer. When the stepped portion is a chip breaker, the above problem does not occur, but the stepped portion position also needs to be changed according to the change in the position of the main cutting edge, and there is a problem that regrinding work is troublesome. . The present invention is based on the above circumstances.
The object was to solve the problems that it takes a long time for re-grinding when the breaker groove is used as a chip breaker and the problem of shortening the service life, or the trouble of grinding work when a stepped part is used as a chip breaker. Is.

[0005]

This object is to provide at least one groove and a land extending in a direction having an axial component on a blade portion of a body extending axially from a shank. A cutting edge is formed by the line of intersection of the rake face and the margin of the reamer, and in the reamer whose tip end is chamfered, a chip breaker extending parallel to the cutting edge is formed on the rake face. Will be solved by. The chip breaker may be a breaker groove formed parallel to the cutting edge on the rake face, and a step formed parallel to the cutting edge at a position spaced a certain distance from the cutting edge of the rake face to the bottom side of the groove. It may be a department. The cutting edge may be formed of the same material as the shank and the body, or may be formed by brazing a tip made of a different material such as cemented carbide or removably fixed.

[0006]

In the reamer constructed as described above, the chips generated at the main cutting edge of the bite part are easily broken through the groove by the chip breaker or spirally wound, and easily cut. It is discharged to the outside. The main cutting edge of the biting part is inclined with respect to the sub cutting edge formed by the line of intersection between the rake face of the land and the margin, while the chip breaker is formed parallel to the sub cutting edge. Therefore, the main cutting edge and the chip breaker are not parallel to each other, and the chips generated at the main cutting edge do not intersect at right angles with the chip breaker. However, since the chips collide with the chip breaker even at an angle, a breaker effect can be obtained.

When the main cutting edge is worn, if the tip surface and the tip chamfered portion are simply ground, a new main cutting edge is formed as a line of intersection between the rake face and the new tip chamfered surface, resulting in sharpness. Recover. The relative positional relationship between the newly formed main cutting edge and the chip breaker is the same as the relative positional relationship between the old main cutting edge and the chip breaker. The new main cutting edge is formed in parallel with the old main cutting edge, and the sub cutting edge only removes a small part adjacent to the main cutting edge and does not grind the other part, so the new main cutting edge and sub cutting edge The relative positional relationship between the main cutting edge and the chip breaker does not change, and the relative positional relationship between the auxiliary cutting edge and the chip breaker does not change. In addition,
As for the sub cutting edge, the part adjacent to the main cutting edge slightly wears due to cutting, and the other part hardly wears because it hardly participates in cutting. It suffices if only a small part is removed.

[0008]

As described above, in the reamer according to the present invention, when the main cutting edge is worn, only the tip surface and the chamfered portion need to be reground, and the chip breaker does not need to be modified. Grinding work is easy, the grinding allowance is small, and the life of the reamer is extended. In particular, when a cutting edge is formed by a CBN sintered body or a diamond sintered body (cubic type boron nitride or diamond sintered on a cemented carbide table at ultrahigh temperature and high pressure), a rake face However, it is difficult to re-form the chip breaker because the sintered body layer becomes thin or disappears. However, according to the present invention, it is extremely convenient because the rake face does not need to be ground. Further, since the CBN sintered body and the diamond sintered body are expensive, the re-grinding allowance is small and the effect of extending the life is particularly large.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the reamer 10 has a generally cylindrical shape, and includes a shank 12 and a body 14 axially extending from a front end surface of the shank 12. A blade portion 16 is formed at the tip of the body 14. As shown in FIG. 2, a liquid hole 20 for ejecting a cutting liquid at the time of cutting an object to be processed is formed in the tip surface 18 at one position. The liquid hole 20 is formed by a liquid passage (not shown) that guides cutting fluid from a cutting fluid supply device (not shown) to the inside of the body 14 through the inside of the shank 12. The cutting fluid reduces the friction generated between the reamer 10 and the workpiece during cutting, and carries away the heat generated by the friction between the two members.

The blade portion 16 extends in the axial direction and includes two grooves 22 and 23 each forming a pair, and lands 24 and 25 which also form two pairs. The land 24 has a rake face 26 forming a groove side surface of the groove 22, and a margin 28 intersecting with the rake face 26, and a first auxiliary cutting edge 30 is formed by a line of intersection between the rake face 26 and the margin 28. Has been done. The first sub-cutting edge 30 is made of the same material as the body 14, and two first sub-cutting edges 30 are formed at diametrically separated positions. The land 25 corresponding to the groove 23 also has a sub cutting edge 32, a rake face 36, a margin 38 and the like. The two sub cutting edges 32 are provided at positions separated by 90 degrees with respect to the first sub cutting edge 30, and the sub cutting edge 32 is slightly retracted from the first sub cutting edge 30 in the axial direction. It is in the position (position on the shank 12 side).

As shown in FIG. 3, the distance of the auxiliary cutting edge 32 from the reamer axis (hereinafter referred to as the cutting edge radius).
Is slightly larger than the radius of the first auxiliary cutting edge 30, so when the reamer 10 rotates to cut the workpiece,
After the first sub-cutting edge 30 first performs lower cutting, the sub-cutting edge 32 whose locus is shown by a chain double-dashed line performs finish cutting,
A hole with high dimensional accuracy and smoothness is formed. Figure 6
As shown in (a) and (b), the tip of the land 24 is chamfered to form a biting portion 40. The cutting edge formed on the biting portion 40 is the first main cutting edge 42, and the chips mainly come out from the first main cutting edge 42. Then, the portion of the first auxiliary cutting edge 30 which is parallel to the axial direction and is adjacent to the first main cutting edge 42 slightly cuts to smooth the surface.

As shown in FIGS. 1 and 2, the rake face 2
A second sub-cutting edge 50 is formed by a line of intersection of the rake face 26 and the margin 48 at a position of 6 further retracted from the sub-cutting edge 32 in the axial direction. The radius of the second sub-cutting edge 50 is set to be larger than the radius of the sub-cutting edge 32 as well as the first sub-cutting edge 30, and the radius of the first sub-cutting edge 30 and the second sub-cutting edge 50 is increased. The second main cutting edge 51 is formed. The vicinity of the opening of the hole cut by the first main cutting edge 42 and the sub cutting edges 30, 32 is further the second main cutting edge 51.
And the diameter is enlarged by being cut by the second auxiliary cutting edge 50.

A portion of the rake face 26, which is separated from the first sub-cutting edge 30 by a certain distance to the bottom side of the groove 22, is raised in a stepped shape, whereby the chip breaker 52 is provided with the first and second sub-cutting edges. It is formed in parallel with 30, 50.
Therefore, as shown in FIG. 4, the chips generated in the direction indicated by the arrow by the cutting with the first main cutting edge 42 (the same applies to the second main cutting edge 51) collide with the chip breaker 52 and become short fragments. It is twisted or spirally wound and easily discharged to the outside through the groove 22. The first and second main cutting edges 42, 51 are inclined with respect to the first and second sub cutting edges 30, 50, while the chip breaker 52 is provided with the first and second sub cutting edges 30, 50. Since it is formed in parallel with the first and second main cutting edges 42, 51 and the chip breaker 5,
Not parallel to 2 and the chips produced by the first main cutting edges 42, 51 do not intersect the chip breaker 52 at right angles. However, since the chips collide with the chip breaker 52 even if it is slanted, the breaker effect can be obtained.

As shown in FIGS. 5 (a), 5 (b) and 5 (c), a chip breaker 60 is formed in the vicinity of the sub cutting edge 32 as in the vicinity of the first sub cutting edge 30. Also,
A notch is formed along the tip breaker 60 at the tip of the rake face 36, and a tip 62 is fitted therein,
It is fixed by brazing. The tip 62 is a diamond sintered body obtained by sintering diamond 66 on a cemented carbide table 64 at ultrahigh temperature and high pressure. The tip portion of the tip 62 is chamfered to form a chamfered portion 68, where the main cutting edge 7
0 is formed. The tip 62 of the sub cutting edge 32 is formed by the tip 62. Since the tip 62 has good sharpness and excellent durability, it is particularly suitable for high-precision cutting. Therefore, this reamer 10
The part of the hole to be processed that requires particularly high accuracy is the chip 6
It is configured to be cut by the two main cutting edges 70 and the sub cutting edges 32.

As the reamer 10 repeatedly cuts the work piece, the cutting edges, especially the main cutting edges 42, 51, 7 gradually increase.
0 wears out. Then, each vicinity of the main cutting edges 42, 51, 70 is reground by a tool grinder or the like, and new main cutting edges 42, 51, 70 are formed as intersection lines between the rake faces 26, 36 and the new chamfered parts. It is formed and the sharpness is restored. In addition, since the sub cutting edges 30, 32, 50 are only worn by the parts adjacent to the first main cutting edges 42, 51, 70, which are involved in cutting, the new main cutting edges 42,
It is sufficient if this part is removed by regrinding to form 51, 70.

The chip breakers 52, 60 are formed parallel to the auxiliary cutting edges 30, 32, 50, and the new main cutting edges 42, 51, 70 are the old main cutting edges 42, 51 ,.
Since it is formed parallel to 70, the main cutting edges 42, 51, 7
The re-grinding of 0 does not change the relative position with respect to the main cutting edges 42, 51, 70. Therefore, it is not necessary to make any changes to the chip breakers 52 and 60, and at the time of re-grinding, it suffices to slightly remove the vicinity of the main cutting edges 42, 51 and 70 and the tip end surface 18. And the effect of extending the life of the reamer 10 can be obtained.

Each of the other embodiments will be described below. The same parts as those in the above embodiment are designated by the same reference numerals and the description thereof will be omitted. In the above example,
Although the chip breakers 52 and 60 were formed as stepped portions, FIG.
It is also possible to use a breaker groove as shown in (a) and (b). The blade portion 78 of the reamer 10 has first and second main cutting edges 84 and 86, and first and second sub cutting edges 88 and 9.
0 is formed. The first auxiliary cutting edge 88 is the rake face 8
0 and a margin 82, and the second auxiliary cutting edge 90 has a rake face 80 and a margin 92.
It is formed by the line of intersection with. The second sub cutting edge 90 has a larger diameter than the first sub cutting edge 88.
The second main cutting edge 86 is formed on the step portions of 8, 90.
First, the holes of the work piece are the first main cutting edge 84 and the first sub cutting edge 8.
8 and the vicinity of the opening of the hole is cut by the second main cutting edge 86 and the second sub cutting edge 90 to increase the diameter. The cutting edges 84, 86, 88, 90 are made of the same material as the body 14. On the rake face 80, a chip breaker 94 consisting of a breaker groove is first
It is formed parallel to the second auxiliary cutting edges 88, 90. That is, since the first and second auxiliary cutting edges 88 and 90 have a rake angle, they have good cutting performance and cutting resistance can be reduced.

When the first and second main cutting edges 84 and 86 are worn, the chamfered portions forming them are ground to form new first and second main cutting edges 84 and 86. At this time, the chip breaker 94 moves the first and second auxiliary cutting edges 88, 9
Since it is provided parallel to 0, the first and second main cutting edges 8
The first and second main cutting edges 8 are not affected by the grinding of 4,86.
4, 86, the first and second auxiliary cutting edges 88, 90 and the relative positional relationship between the chip breaker 94 do not change. Therefore, as in the conventional case, the chip breaker has the first and second main cutting edges 84, 8
As in the case of being formed in parallel with 6, the chip breaker 9
Since it is not necessary to re-form 4, and the grinding allowance is small, the re-grinding work can be easily performed and the life of the reamer 10 can be extended.

The first auxiliary cutting edge 8 as in the embodiment shown in FIG.
It is desirable to form the chip breaker 94 in common when the distance between the second auxiliary cutting edge 90 and the second sub cutting edge 90 is narrow, but it is desirable to provide a plurality of chip breakers when the distance is large. Blade portion 100 shown in FIGS. 8 (a) and 8 (b)
Includes first and second main cutting edges 102 and 104 and first and second sub cutting edges 106 and 108.
02, 104, 106 and 108 are made of the same material as the body 14.

The rake face 109 has a first auxiliary cutting edge 106.
And chip breakers 110 and 112 made of breaker grooves are formed in parallel with the second sub cutting edge 108, respectively. In this embodiment, the chip breakers 110 and 11 are
Since 2 can be formed under the optimum conditions for the first and second main cutting edges 102 and 104, respectively, the chips can be made fine.

Although the breaker groove in each of the embodiments shown in FIGS. 7 and 8 was formed from the position of the auxiliary cutting edge, as shown in FIG. 9, the auxiliary cutting edge 12 of the rake face 120 was formed.
The chip breaker 124 may be formed by forming a breaker groove from a position slightly apart from 2. By doing so, the cutting edge 122 formed by the rake face 120 and the margin 126 has a cutting edge angle close to a right angle, and the durability of the cutting edge 122 is improved. Alternatively, as shown in FIG. 10, a state in which the cutting edge 132 is slightly lower than the rake face 130,
That is, the chip breaker 134 may be formed by forming a breaker groove so that the chip breaker δ has a down-center δ. By doing so, sharpness is improved and cutting resistance can be reduced.

Further, as shown in FIG. 11, when the diamond sintered body tip 144 is fitted and brazed to the notch 142 formed at the tip of the rake face 141 of the blade portion 140, the depth of the notch 142 is increased. It is also possible to make the tip larger than the thickness of the tip 144 and form a stepped portion between the portion of the rake face 141 formed by the tip 144 and the portion formed by the reamer body to form the tip breaker 148. is there. When the chip 144 is made of a diamond sintered body, it is difficult to re-form the chip breaker 148 because the sintered body layer of the chip 144 becomes thin or disappears if the rake face 141 is ground. According to the present invention, since it is not necessary to grind the rake face 141, it is very convenient. Further, since the diamond sintered body is expensive, the re-grinding margin is small, and the life of the reamer 10 is long, which is particularly effective.

In each of the embodiments shown in FIGS. 5 and 11, the tips 62 and 144 are formed from a diamond sintered body obtained by sintering diamond on a cemented carbide table. Alternatively, a chip made of a CBN sintered body obtained by sintering cubic crystal boron nitride may be used. Furthermore, the tips 62 and 144 can be detachably fixed as throw-away tips. The throw-away tip means a tip that is discarded without re-grinding, but an expensive throw-away tip is also re-ground and used. However, if you re-grind, the dimensions will change, and the advantage of the throw-away tip that the position of the cutting edge will not change even if you attach or detach it is lost. It is often used to If the tip of the auxiliary cutting edge of this throw-away tip is chamfered to form the main cutting edge and the tip breaker is formed parallel to the sub-cutting edge, re-grinding becomes easier and the throw-away tip becomes The number of reusable times can be increased. In addition to the above, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front view showing a reamer with a chip breaker that is an embodiment of the present invention.

FIG. 2 is a left side view of the reamer.

FIG. 3 is a diagram showing one cutting edge of the reamer by a solid line and a rotation locus of another cutting edge by a chain double-dashed line.

FIG. 4 is a plan view showing a cutting situation by the cutting edge.

FIG. 5 is an enlarged view showing the other cutting edge, (a) is a side view, (b) is a front view, and (c) is a bottom view.

FIG. 6 is an enlarged view showing the one cutting edge, (a)
Is a side view and (b) is a front view.

FIG. 7 is a view showing a cutting edge in a reamer with a chip breaker which is another embodiment of the present invention, (a) is a side view and (b) is a front view.

FIG. 8 is a view showing a cutting edge in a reamer with a chip breaker which is still another embodiment of the present invention, (a) is a side view and (b) is a front view.

FIG. 9 is a side view showing a chip breaker in a reamer with a chip breaker which is still another embodiment of the present invention.

FIG. 10 is a side view showing a chip breaker in a reamer with a chip breaker which is still another embodiment of the present invention.

FIG. 11 is a side view showing a chip breaker in a reamer with a chip breaker which is still another embodiment of the present invention.

[Explanation of symbols]

10 Reamer 12 Shank 14 Body 16, 78, 100, 140 Blade 22, 23 Groove 24, 25 Land 26, 36, 80, 120, 130, 141 Rake face 28, 38, 48, 82, 92, 126 Margin 42, 51, 70, 84, 86, 102, 104 Main cutting edge 30, 32, 50, 88, 90, 106, 108 Sub cutting edge 52, 60, 94, 110, 112, 124, 134,
148 Chip Breaker

Claims (1)

[Claims] 1. A blade portion of a body axially extending from a shank, at least one of which extends in a direction having an axial component.
Grooves and lands are provided one by one, and a cutting edge is formed by the line of intersection between the rake face of the land and the margin, and in a reamer having a tip chamfered at the tip of the blade portion, the rake face is A reamer with a chip breaker, wherein a chip breaker extending parallel to the cutting edge is formed.