JP3525349B2 - Cutting tool holder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool holder (hereinafter also simply referred to as a holder) to which a chip used for turning or rolling, in particular, a throwaway chip (hereinafter simply referred to as a chip) is detachably mounted. ) Concerning.

[0002]

2. Description of the Related Art When mounting (clamping) a chip on a holder of this type, the chip is screwed so that its lower surface and side surface (flanking surface side) are constrained by the bottom surface and wall surface of the chip seat of the holder, respectively. It is tightened by a clamping means such as a member. At this time, the corner between the bottom surface and the wall surface of the chip seat in the holder (hereinafter, also referred to as the corner angle of the chip seat or simply the corner angle) is the corner at which the lower surface and the side surface of the chip intersect (hereinafter, the corner of the chip or If it is hit by just the corner), stable mounting cannot be secured. For this reason, the corner angle of the chip seat has conventionally been formed as follows.

That is, when the tip to be mounted is a positive type tip 21 having a clearance angle at the cutting edge as shown in FIG. 11, the angle θ of the corner angle 98 of the tip seat 92 is set to the tip 21. It was almost the same as the angle 24, and was sharpened within the range where processing (molding) was possible. Also,
As shown in FIG. 12, in order to reliably prevent the corner 24 of the tip 21 from coming into contact with the corner 108 of the tip seat 102, the wall surface of the near chamber of the corner 108 is vertically cut to positively escape 104a. It is also known that meat is formed so as to retain some voids. Then, as shown in FIG. 13, a negative type tip 31 having no clearance angle of the cutting edge.
In the holder for mounting, the corner angle 118 at which the bottom surface of the chip seat 112 and the wall surface intersect is set to a substantially right angle and finished as sharply as possible. The angle of the corner of the tip seat was actually smaller than the angle of the tip by about 1 degree regardless of whether the tip was positive or negative. In this way, in order to prevent the corner from hitting the corner of the tip seat regardless of the type of tip to be mounted, negative or the like, and regardless of the angle of the tip,
The corner of the chip seat was formed to be sharp.

[0004]

However, when the chip is clamped and cut in the chip seat of such a conventional holder, there are the following problems. That is, in the cutting process, the force (cutting resistance) received by the cutting edge of the tip acts on the bottom surface and the wall surface of the tip seat via the bottom surface and the side surface of the tip,
It acts to push the corners apart. For this reason, when machining with extremely large cutting resistance or heavy cutting such that the blade contact is intermittent, the holder 91 shown in FIG. 14 is used.
There is a problem in that extremely large stress concentration occurs in the corners 98 and 99 of the tip seat 92, and cracks (K) easily enter from the corners, and the holder 91 is broken (damaged) in a short time (period). there were. The problem is that the bottom surface 93 and the wall surface 9
The smaller the angle of the corner angles 98, 99 where 4, 95 intersect, and the sharper the angle angles 98, 99, the more likely they are to occur. And, these things do not only stop the damage of the holder, but also contribute to the reduction of sharpness during processing,
It also reduces the precision of the finished surface. In addition, in such a case, it is necessary to interrupt the processing and perform the setup again each time, which lowers the work efficiency. An object of the present invention is to eliminate the problems of such conventional holders.

[0005]

In order to solve the above problems, a holder for a cutting tool according to claim 1 of the present invention.
The chamfer is provided on the corner between the bottom of the seat and the wall.
Then, the chamfer was cut at a surface perpendicular to the direction along the corner.
In the case of cross section, the half that touches the bottom surface and the wall surface
Being a concave roundness larger than a circular arc with a diameter of 0.15 mm
Is characterized by. And, according to claim 2 of the present invention,
The cutting tool holder is installed between the bottom surface of the insert seat and the wall surface.
A chamfer is applied to the corner, and the chamfer is straight in the direction along the corner.
In the cross section when cut by a square surface, C with a 45 degree chamfer
Larger than 0.15 mm and 35 degrees to the bottom surface
Characterized by forming a substantially linear slope in the range of 55 degrees
And

[0006]

By the above means, the corner angle between the bottom surface and the wall surface of the chip seat is chamfered. Therefore, stress concentration at the corner angle during cutting is reduced compared to the case without this chamfer. It can be reduced. Therefore, it is effective to prevent the occurrence of cracks and breakage of the holder.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a holder according to the present invention is embodied will be described in detail with reference to FIGS. In the figure, 1 is a holder, and in this example, a carbide tip (2
It is for an end mill formed so as to be fitted with a (single blade) 21. As shown in FIG. 1, the chip seat 2 is formed in a substantially rectangular recess, and has a flat bottom surface 3 that restrains the bottom surface of the chip and two wall surfaces 4 and 5 that rise from the bottom surface 3. However, in this example, the chip 21 to be mounted is of the rectangular positive type, and the wall surfaces 4 and 5 are the bottom surface 3 respectively.
Is formed so as to intersect at a predetermined angle (100 degrees in this example). In addition, a relief 6 of the corner of the cutting edge of the tip is recessed at the corner of the tip seat 2 in a plan view. The height of the wall surfaces 4 and 5 is set to be slightly smaller than the height (thickness) of the side surface of the chip. A screw hole 7 for fixing a chip is provided at a substantial center of the bottom surface 3.

Now, in this example, the corner angles 8 and 9 intersecting between the bottom surface 3 of the tip seat 2 and the wall surfaces 4 and 5 are cut along a plane perpendicular to the respective corner angles 8 and 9. In the cross section in the case of the above, a concave roundness having a predetermined radius which is substantially in contact with the bottom surface 3 and the wall surfaces 4 and 5 is provided along the respective corner angles 8 and 9. As a result, in this example, fillets 8a and 9a having a substantially triangular prism shape are formed along the entire corners 8 and 9. However, in this example, the radius of the roundness is R0.4 mm.
Is set to. Note that this chamfer radius is approximately R0.
It was in the range of 4 mm ± 0.02 mm.

As shown in FIGS. 2 and 3, this holder 1 has a corner 2 at which the lower surface 22 and the side surface 23 intersect with each other.
4 has a C-chamfered tip 21, that is, a rectangular positive type with a chamfer (C0.5 mm in this example) of a size that does not contact the corners (fillet) 8, 9 of the tip seat 2. When the tip of is attached by tightening the screw member N,
The corner 24 of the tip 21 does not abut the corners 8 and 9 of the tip seat 2 (see FIGS. 3 and 4). Therefore, this example is a comparative example in which the condition of cracking or breaking (loss) is not chamfered positively in the corner of the chip seat, and the condition is different. Accuracy, measured value R 0.1 or less). However, the material of the holder 1 is SC
The blade diameter is 14 mm when the tip is mounted, and the height of the wall surfaces 4 and 5 of the tip seat 2 is 1.88 mm. The height (thickness) of the side surface 23 of the chip 21 is 2.
It is 18 mm, and the angle between the lower surface 22 and the side surface 23 is 101 degrees. In this test, the gear (material SC
r420, HB180, number of teeth 40), and chamfering of the tooth surface. Cutting conditions were: cutting speed 70 m / min, depth of cut 3 mm x 3 mm x 3 mm (maximum), axial feed 0.
25 mm / blade (0.25 mm axial feed per blade).

In the results of this example, the holder 1 did not show any abnormalities such as breakage even after the number of machined teeth was 10 million, but in the comparative example, when the number of machined teeth was about 200,000. Then, the part of the tip seat was broken. As will be verified from this result, it is understood that the stress concentration generated in the corner angles 8 and 9 of the tip seat 2 during cutting can be significantly reduced in the present example.

When the chamfer has a rounded concave shape, the chamfer (radius of curvature R) has an appropriate value,
The same processing as described above was performed and durability was tested. The results are shown in Table 1 by the radius of curvature R. However, each of the arcs was assumed to be in contact with the bottom surface and the wall surface.

[Table 1] From this result, since the chamfering was not performed positively as in the comparative example, the finishing accuracy (point of sharpness) of the corner angle was R0.1.
It can be seen that, when the radius is positively rounded, the durability is more than doubled even when the radius is 0.15 mm, as compared with the case where the radius is less than or equal to mm. Above all, R0.2mm
In the case of, the durability was markedly improved to 30 times or more as compared with the comparative example. From these facts, when the chamfer is formed into a concave round shape, it is preferable that the roundness is larger than R0.15 mm from the viewpoint of manufacturing. In order to reduce the stress concentration, the larger the chamfer (radius of the arc) is, the more effective it is. However, in order to stabilize the chip when mounting it, that is, to prevent the chip from loosening, the chip size or chip 75% of the height of the seat wall, depending on the height of the seat wall
It is preferable to set it in a range smaller than (3/4). It should be noted that the circular arcs should preferably be on the bottom surface 3 and the wall surfaces 4, 5 as in this example.
It is preferable to contact with.

On the other hand, as shown in FIG. 5, as compared with the previous example, the chamfer of the corner 18 of the tip seat has a concave roundness (arc shape).
Instead of, only the point formed in a linear 45-degree inclination (45-degree chamfer) is different, but the durability is the same as that shown in Table 2 depending on the size of the chamfer (C) at the corner. Met. The chamfer angle was in the range of 45 ° ± 10 °.
In this example, a chamfer of approximately 45 degrees is obtained in a cross section when cut by a plane perpendicular to a direction along an intersecting corner angle 18 between the bottom surface 3 of the chip seat and the wall surface 4 and the wall surface 5 (not shown). As a result of the linear inclination that is formed along the entire angle, a fillet having a triangular prism shape is formed along the angle. In the comparative example, chamfering was not positively performed as in the previous case, and the angle of the corner can be considered to be the measured value C of 0.1 mm or less.

[Table 2]

From this result, since the chamfering was not positively performed unlike the comparative example, the sharpness of the corner angle was C0.1.
It can be seen that, when the chamfering is positively applied, the durability is more than doubled even when the chamfering is 0.15 mm, as compared with the case of less than mm. Above all, C0.2mm
In the case of, the durability was markedly improved to 30 times or more as compared with the comparative example. From this, in the case of 45 degree chamfering, C0.1
It is preferably larger than 5 mm. For the same reason as described above, this radius may be set within a range smaller than 75% (3/4) of the height of the wall surface of the tip seat. In addition, it is preferable that the angle θ of the chamfer (inclination) attached to the corner is as close as possible to 45 degrees, but it is 35 to 5 with respect to the bottom surface.
It is appropriate in manufacturing to provide a tolerance of 5 degrees, that is, ± 10 degrees.

In the above description, since the tip seat is used to mount a positive type tip, the angle of the corner angle at which the bottom surface and the wall surface intersect is 100 degrees, but in the present invention, this angle is 89-. The same can be applied to a holder for mounting a negative type chip at 90 degrees. However, in that case, stress concentration is likely to occur due to the smaller angle, so it is preferable to make the chamfer (concave roundness or linear inclination) as large as possible.

FIGS. 6 and 7 both show an embodiment for a negative type chip 31, and FIG. 6 shows an embodiment in which a concave roundness is provided at a corner angle 48 between the bottom surface 43 and the wall surface 44 of the tip seat. In addition, FIG. 7 shows an embodiment in which a linear inclination is provided at a corner angle 58 between the bottom surface 53 and the wall surface 54. However, the chip 31 to be mounted is appropriately chamfered so that its corner does not come into contact with the corner.

In the present invention, the chamfering can be carried out as follows, although the performance is slightly lowered.
That is, as illustrated in FIGS. 8 to 10, at the corner of the tip seat, chamfering can be performed in such a manner that the bottom surface or wall surface of the near chamber or both surfaces thereof go into the depth of the corner. In this way, the chip can be mounted without chamfering the corner of the chip. FIG. 8 shows a case where the positive type chip 21 is mounted, and the part of the near wall of the corner angle 68 of the wall surface 64 is cut at a right angle to the bottom surface 63 to form an escape 64a. Bottom 6
In this embodiment, the corner intersecting with 3 is chamfered (concave roundness). In addition, FIG. 9 shows a case where the positive type chip 21 is mounted, and the portion of the wall chamber 74 near the corner 78 is the bottom surface 7.
A relief 74a is formed by cutting at a right angle with respect to 3, and at the corner where the surface of the relief 74a and the bottom surface 73 intersect, the bottom surface 73 of the near chamber of the corner angle 78 is slightly shaved off to form a concave roundness. It is an example in which a chamfer is formed. Figure 10
Is an embodiment in which the roundness in FIG. 8 is a linear inclination,
In the case of mounting the positive type chip 21, the part of the near wall of the corner 88 of the wall surface 84 is cut at a right angle to the bottom surface 83 to form the escape 84a, and the surface of the escape 84a and the bottom surface 83 are formed. This is an example in which a 45 degree chamfer is applied to the intersecting corner. It should be noted that these can be applied not only to those in which positive type chips are mounted but also to those in which negative type chips are mounted.

In the above-mentioned embodiment, the chip has a rectangular two-corner specification, but the present invention is not limited to this, and a diamond-shaped chip may be used depending on the processing form.
It can be embodied in a holder provided with a chip seat for mounting an appropriate chip such as a triangular chip or a circular chip. Further, in the previous example, the chip is embodied by clamping by screwing a screw member into a screw hole provided in the center of the chip, but the present invention can also be applied to a clamp type holder in which a screw is tightened via a presser foot. Further, in the above-mentioned embodiment, the case where it is embodied in the end mill is illustrated, but the present invention can be widely applied to a holder for cutting tools such as a boring bar and a turning tool (holder).

[0018]

According to the present invention, since the corner angle between the bottom surface and the wall surface of the chip seat is positively chamfered, the stress concentration generated in the corner angle during cutting is correspondingly reduced. Since this can be reduced, the occurrence of cracks generated from the corners of the chip seat can be effectively prevented, and the holder can be prevented from breaking (damage). As a result, it is expected that the accuracy of the finished surface and the work efficiency will be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing an embodiment in which a holder for a cutting tool according to the present invention is embodied and a partially enlarged view thereof.

2A and 2B are a front view and a partially enlarged view of a state in which a tip is mounted on the cutting tool holder shown in FIG.

FIG. 3 is a view and a partially enlarged view of the cutting tool holder shown in FIG.

4 is a partially enlarged cross-sectional view common to the AA cross section and the BB cross section in FIG. 2 (partial cross section when cut along a plane perpendicular to the direction along the corner).

5 is a partial cross-sectional view of an embodiment in which a corner angle in FIG. 4 is chamfered by 45 degrees.

FIG. 6 is an explanatory view of an embodiment in which the present invention is embodied in a tip seat for mounting a negative type tip, and is a partial cross-sectional view taken along a plane perpendicular to a direction along a corner angle.

FIG. 7 is a partial cross-sectional view of an embodiment in which a corner angle in FIG. 6 is chamfered by 45 degrees.

FIG. 8 is an explanatory view of another embodiment of the corner angle of the tip seat in which the positive type tip is mounted, and is a partial cross-sectional view taken along a plane perpendicular to the direction along the corner angle.

FIG. 9 is a partial cross-sectional view of the modification of FIG. 8 when cut along a plane perpendicular to the direction along the corner.

FIG. 10 is a partial cross-sectional view of another modification of FIG. 8 when cut along a plane perpendicular to the direction along the corner.

FIG. 11 is a partial cross-sectional view for explaining a state in which a positive type chip is mounted on a conventional chip seat, taken along a plane perpendicular to a direction along a corner.

FIG. 12 is a partial cross-sectional view for explaining a state where a positive type tip is mounted on another conventional tip seat when the tip is cut along a plane perpendicular to a direction along a corner angle.

FIG. 13 is a partial cross-sectional view for explaining a state in which a negative type tip is mounted on a conventional tip seat, when being cut along a plane perpendicular to a direction along a corner.

FIG. 14 is a perspective view of a main part for explaining an example of a conventional cutting tool holder and a partially enlarged view thereof.

[Explanation of symbols]

1 holder 2 chip seat 3,43,53,63,73,83 Bottom 4,5,44,54,64,74,84 Wall surface 8,9,18,48,58,68,78,88

   ─────────────────────────────────────────────────── ─── Continued front page       (56) Reference Bibliography 5-70820 (JP, U)

Claims (2)

(57) [Claims] 1. A chamfer is applied to a corner between a bottom surface and a wall surface of the tip seat, and the chamfer is a surface perpendicular to a direction along the corner.
In the cross section when cut, contact the bottom surface and the wall surface.
It has a concave roundness larger than an arc with a radius of 0.15 mm.
Holder for cutting tool according to claim Rukoto. 2. A surface at the corner between the bottom surface and the wall surface of the chip seat.
The chamfer is a plane perpendicular to the direction along the corner.
In the cross section when cut, C0.15m at 45 degree chamfer
greater than m and 35 to 55 degrees with respect to the bottom surface
Cutting characterized by forming a nearly linear slope in the range of
Tool holder.