JP2003071622A - Throw-away type drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent generation of play and falling in a throw-away tip 8 when attachably/detachably mounting the throw-away tip 8 on a recessed groove-shaped tip mounting seat 6 by pressing the throw-away tip 8 by a clamp screw 16. SOLUTION: In this throw-away type drill, the recessed groove-shaped tip mounting seat 6 is formed along a plane including an axis O to be opened on a distal end surface 3 of a substantially cylindrical drill main body 1 to be rotated around the axis O, at the distal end of the drill main body 1. The flat throw-away tip 8 formed with a cutting edge 7 at its distal end is attachably/detachably mounted on the tip mounting seat 6 by a clamp screw 16 screwed into the drill main body 1. The clamp screw 16 can be pressed to the screwing direction side of the clamp screw 16 by a stopper screw 18 screwed into the drill main body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat insert insert (hereinafter referred to as a insert) in which a cutting edge is formed on a tip of a groove-shaped insert mounting seat formed on the tip of a drill body. ) Relates to a throw-away type drill that is detachably attached.

[0002]

2. Description of the Related Art As a throw-away type drill of this type, the inventors of the present invention have disclosed in Japanese Patent Application No. 10-8086 that a tip of a drill body is provided along a plane including the axis of rotation of the drill body. A groove-shaped chip mounting seat is formed so as to extend, and a round hole (mounting hole) is formed on the bottom surface of the chip mounting seat facing the tip side, while facing the bottom surface of the chip mounted on the chip mounting seat. On the rear end surface, a cylindrical shaft portion (mounting shaft portion) that can be fitted into the round hole is provided.
After mounting the tip by inserting this shaft into the round hole, engage the engaging member protruding from the inner circumference of the round hole with the notch formed in the shaft to fix the tip to the drill body. I'm proposing something to do. However, according to the throw-away type drill having such a configuration, the tip can be attached only by pushing the tip into the tip mounting seat while inserting the shaft portion into the round hole, and when removing the tip, Since it suffices to pull out the tip to the tip side, the work of exchanging the tip can be performed extremely easily.

[0003]

However, in such a throw-away type drill, since the tip is attached to the drill body only by the engagement of the engaging member protruding and retracting from the attaching hole, this engaging member is, for example, If the spring is biased so that it can be retracted into the mounting hole, if the biasing force of this spring is weakened, the stability of the chip mounting will be impaired and rattling will occur. In some cases, the chip may fall off the chip mounting seat. So, in order to solve such a problem,
It is conceivable that a chip is clamped and mounted by forming a clamp screw hole that opens in the mounting hole in the drill body, and screwing a clamp screw into the clamp screw hole and pressing the mounting shaft portion. However, even if the tip is attached with such a clamp screw, the clamp screw itself may loosen during long-term use, which may cause rattling of the tip or the tip may fall off. It is impossible to completely eliminate the possibility of accidents.

The present invention has been made under such a background, and when the chip is pressed by the clamp screw to be removably attached to the groove-shaped chip mounting seat as described above, It is an object of the present invention to provide a throw-away drill that can reliably prevent rattling and falling.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems and to achieve such an object, the present invention is directed to a tip end portion of a substantially cylindrical drill body which is rotated around an axis. A grooved tip mounting seat is formed along the plane including the axis line by opening at the tip surface of the, and a flat tip having a cutting blade formed at the tip is formed on the drill body in the tip mounting seat. A throw-away type drill detachably attached by a clamp screw to be screwed, wherein the clamp screw can be pressed in a screwing direction side of the clamp screw by a stopper screw screwed into the drill body. It is a thing. Therefore, in such a throw-away drill, the stopper screw presses the clamp screw toward the screwing direction side, so that the loosening of the clamp screw can be prevented, and therefore the tip is rattled even during long-term use. No sticking or dropping occurs, and it becomes possible to perform smooth and stable drilling until the life of the chip is exhausted.

Here, in order to enable the clamp screw to be pressed in the screwing direction by the stopper screw in this way, for example, a clamp screw hole into which the clamp screw is screwed and a stopper screw hole into which the stopper screw is screwed are provided in the drill body. The openings are formed so as to communicate with each other and are formed adjacent to each other, and the stopper screw is provided with a head. By screwing the stopper screw into the stopper screw hole, the head causes the clamp screw to move toward the screwing direction. It can be made to press.
Further, in this case, even if it is a throw-away type drill in which the outer diameter of the cutting edge is relatively small by forming the stopper screw hole adjacent to the clamp screw hole in the axial direction. , It is possible to secure the mounting stability of the tip without impairing the strength and rigidity of the drill body.

[0007]

1 to 6 show an embodiment of the present invention. In the present embodiment, the drill body 1 has a substantially multi-stage cylindrical outer shape centered on an axis O in which the tip portion is reduced in diameter by one step with respect to the shank portion 2 on the rear end side, and the drill body is provided on the outer periphery of the tip portion. A pair of chip discharge grooves 4 and 4 opening on the front end surface 3 of 1 are opposite to each other across the axis O, and are rearward in the drill rotation direction T during drilling around the axis O toward the rear end side. It is formed in a spiral shape so that it can be twisted to the side. In addition, an oil hole 5 for supplying a cutting fluid from the rear end surface of the shank portion 2 along the axis O is formed in the drill body 1 toward the tip side. Further, at the tip of the drill body 1, there is formed a groove-shaped tip mounting seat 6 that opens to the tip surface of the drill body 1. The tip mounting seat 6 is provided with a cutting blade 7 at the tip. The chip 8 is detachably attached.

The tip mounting seat 6 is formed so as to have a notch in the diameter direction with respect to the axis O between the wall surfaces facing the drill rotation direction T side at the tip ends of the chip discharge grooves 4, 4. A groove bottom surface 6a extending in a direction orthogonal to the axis O, and a pair of groove wall surfaces 6b and 6b orthogonal to the groove bottom surface 6a and facing each other in parallel and extending parallel to the axis O. The groove bottom surface 6a and the groove wall surfaces 6b, 6b are formed so as to open in a U-shape toward the tip surface 3 in a side view. Further, a mounting hole 9 having a circular cross section centered on the axis O is formed on the bottom surface 6a of the groove, and the mounting hole 9 is communicated with the tip of the oil hole 5 and the mounting hole is formed. The diameter of 9 is made slightly larger than the interval between the groove wall surfaces 6b, 6b of the tip mounting seat 6, and such a mounting hole 9 remains the same diameter along the axis O and the drill body 1
By being extended to the tip of the groove wall surface 6b, 6b
At the inner peripheral portion on the axis O side in the diametrical direction,
The groove 10 having a bottom surface whose cross section orthogonal to the axis is arcuate is formed so as to extend parallel to the axis O and open to the tip surface 3.

On the other hand, the tip 8 to be mounted on the tip mounting seat 6 is formed of a hard material such as cemented carbide into a substantially pentagonal flat plate shape as shown in FIGS. The flat plate is attached to the chip mounting seat 6 with the thickness direction of the flat plate being perpendicular to the axis O and the diametrical direction. Here, the tip surface 11 of the tip 8 is
The tip 8 is formed in an isosceles triangular shape that gradually recedes from the axis O toward the outer peripheral side in the attached state where the tip 8 is attached to the tip attachment seat 6 as described above. And both sides 12 of the chip 8
Of the above, the cutting edges 7 are formed at the ridges that intersect with the rake face 12a facing the drill rotation direction T in the attached state.

The side surface portion, which is the rake face 12a, is an inclined surface that gradually narrows toward the rear end side of the chip 8 and gradually recedes toward the side face 12 on the opposite side. In, the chip discharge groove 4 is connected to the wall surface facing the drill rotation direction T. On the other hand, portions of the side surfaces 12 and 12 other than the rake surface 12a are flat surfaces 12b and 12b which are parallel to each other and also parallel to the axis O in the mounted state. The distance between them, that is, the thickness of the chip 8 is made slightly smaller than the distance between the groove wall surfaces 6b and 6b of the chip mounting seat 6, and when the chip 8 is mounted on the chip mounting seat 6, the flatness of these Surface 12b, 1
2b is in close contact with the groove wall surfaces 6b, 6b while being in sliding contact therewith, so that the chip 8 fits into the concave groove formed by the chip mounting seat 6. At this time, due to the flat surfaces 12b, 12b and the recessed grooves 10, 10 of the groove wall surfaces 6b, 6b, a gap having a cross section surrounded by an arc and its chord is formed from the mounting hole 9 to the tip surface. It is designed to be defined over three.

Further, on the rear end surface 13 of the chip 8,
A substantially cylindrical mounting shaft portion 14 is formed so as to be coaxial with the axis O in the mounted state. This mounting shaft 1
Reference numeral 4 denotes a barrel-shaped cross section in which both side portions of a cylinder having an outer diameter which can be fitted into the mounting hole 9 are cut out by flat surfaces 14a and 14a obtained by extending the flat surfaces 12b and 12b of the side surfaces 12 and 12 flush with each other. In addition, the length is slightly shorter than the depth of the mounting hole 9 from the groove bottom surface 6a. Therefore, when the chip 8 is mounted on the chip mounting seat 6,
The mounting shaft portion 14 is fitted into the mounting hole 9 to position the chip 8 in the diametrical direction, and the rear end surface 13 of the chip 8 is brought into contact with the groove bottom surface 6a so as to be in close contact therewith. Of the oil hole 5 is positioned in the direction of the axis O and the tip 8 is thus mounted, the oil hole 5 extends from the mounting hole 9 to its inner periphery and the mounting shaft portion 1.
4 between the flat surfaces 14a and 14a, and the groove 8 and the groove wall surfaces 6b and 6b of the chip mounting seat 6 and the chip 8 respectively.
The cutting oil can be discharged from the tip surface 3 to the bottom of the machined hole through the gap between the flat surfaces 12b and 12b. Further, the outer peripheral surface of the mounting shaft portion 14 further intersects with one obtuse angle of the flat surfaces 14a, 14a in the circumferential direction of the mounting shaft portion 14, and the rear end side of the mounting shaft portion 14, that is, the axis O.
A planar notch 14b is formed so as to be slightly separated from the axis O as it goes toward the rear end side in the direction.

On the other hand, a clamp screw hole 15 is formed in one of the lands defined between the chip discharge grooves 4 and 4 on the outer periphery of the tip of the drill body 1, and the clamp screw hole 15 is formed.
Has a center line C extending in a direction intersecting the axis O and being orthogonal to the cutout portion 14b of the mounting shaft portion 14 when the chip 8 is mounted on the chip mounting seat 6 as described above. When the clamp screw 16 is screwed into the clamp screw hole 15, the tip end of the clamp screw 16 presses the notch portion 14b to press the mounting shaft portion 14, and the chip 8 is drilled. It is adapted to be fixed to the main body 1. The clamp screw 16 does not have a head like a hexagon socket set screw, and the opening of the clamp screw hole 15 on the outer peripheral side of the drill body 1 has a screw formed on the inner periphery thereof. In addition, the clamp screw 16 has a diameter larger than that of the screw hole portion on the inner peripheral side, and the rear end portion of the clamp screw 16 is slightly pressed at the rear end portion while the notch portion 14b is pressed as described above. It has a length that protrudes into.

Further, a stopper screw hole 17 is formed in one of the lands so as to be adjacent to the rear side of the clamp screw hole 15 in the direction of the axis O, and a stopper screw 18 is screwed into the stopper screw hole 17. There is.
Here, the stopper screw hole 17 has a center line X in a direction parallel to the center line C of the clamp screw hole 15 and intersecting the axis O, and an opening on the outer peripheral side of the drill body 1 has the clamp screw hole 15 described above. Similarly to the above, it has a large diameter portion in which a screw is not formed on the inner circumference, and moreover, the clamp screw hole 15
It overlaps with the opening of the and has a snowball shape as shown in FIG. However, the screw-formed portions on the inner peripheral side of both screw holes 15 and 17 do not overlap. The stopper screw 18 screwed into the stopper screw hole 17 is, for example, a pan head screw, a flat head screw, a round head screw,
Like a truss machine screw and a bind machine screw, it has a head portion 18a, and the outer diameter of the head portion 18a is accommodated in the opening when the stopper screw 18 is screwed into the stopper screw hole 17. It is possible, and it protrudes into the overlapping portion with the opening of the clamp screw hole 15,
As shown in, the back surface of the head portion 18a abuts on the rear end portion of the clamp screw 16 screwed into the clamp screw hole 15, and the clamp screw 16 is moved toward the screwing direction side, that is, the inner peripheral side of the drill body 1. The size is such that it can be pressed.

Therefore, in the throw-away drill constructed as described above, even if the clamp screw 16 for fixing the tip 8 by pressing the mounting shaft portion 14 of the tip 8 is loosened, the stopper screw 18 is provided. This loosening can be prevented by screwing in and pressing the clamp screw 16 in the screwing direction. Therefore, the rattling of the chip 8 may occur even after long-term use.
Furthermore, the tip 8 can be stably fixed to the drill body 1 without causing a dropout or the like, which enables smooth drilling.

Further, in this embodiment, when the clamp screw 16 can be pressed in the screwing direction by the stopper screw 18, the clamp screw hole 15 and the stopper screw hole 17 are formed adjacent to each other in the drill body 1. The large-diameter openings are communicated with each other, and the stopper screw 18 is screwed into the head portion 18a to press the clamp screw 16. Therefore, for example, even when the cutting edge 7 of the tip 8 is worn and the tip 8 is replaced, these stopper screws 1
8 and the clamp screw 16 are not completely pulled out from the screw holes 15 and 17, and the tip of the clamp screw 16 is the chip 8
Since the chip 8 can be removed only by loosening the screws 16 and 18 to such an extent that it does not interfere with the cutout portion 14b of the mounting shaft portion 14, the tip 8 can be easily replaced, and the tip 8 can be replaced easily. It is possible to prevent the situation in which the clamp screw 16 and the stopper screw 18 are lost during the work.

Moreover, when the clamp screw hole 15 and the stopper screw hole 17 are formed adjacent to each other in this way,
In this embodiment, the stopper screw hole 17 is formed so as to be adjacent to the clamp screw hole 15 in the axis O direction of the drill body 1. However, this point, for example, it is possible to form the clamp screw hole 15 and the stopper screw hole 17 so as to be adjacent to each other in the circumferential direction of the drill body, but in particular, a small diameter throw-away type in which the outer diameter of the cutting edge 7 is small. In the drill, when the screw holes 15 and 17 are adjacent to each other in the circumferential direction in this manner, the thickness of the drill body 1 is reduced in the circumferential direction in one of the lands where the screw holes 15 and 17 are formed. Axis O that acts on the chip 8 during drilling
While one tip end side portion of this land may become unbearable to the load to the rear side in the rotation direction T around, in the present embodiment, the strength and rigidity of the drill body 1 at this tip end side portion are sufficiently secured. Thus, the mounting stability of the chip 8 can be maintained. In the present embodiment, the clamp screw hole 15 and the stopper screw hole 17 are connected to each other by the axis O
However, they may be arranged adjacent to each other in the spiral direction along the twisting of the chip discharge groove 4 or the land, for example.

[0017]

As described above, according to the present invention,
When a chip is attached to the groove-shaped chip mounting seat formed on the drill body with the clamp screw, the clamp screw is pressed in the screwing direction by the stopper screw, which causes the clamp screw to loosen even during long-term use. Therefore, the mounting stability of the chip can be maintained and smooth drilling can be achieved.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is an enlarged front view of the embodiment shown in FIG. 1 viewed from the tip side.

FIG. 3 is a ZZ sectional view in FIG.

FIG. 4 is a plan view of a throw-away tip 8 attached to the embodiment shown in FIG.

5 is a front view of the throw-away tip 8 shown in FIG.

6 is a side view of the throw-away tip 8 shown in FIG.

[Explanation of symbols] 1 drill body 3 Tip surface 6 Tip mounting seat 7 cutting edge 8 throw-away tip 9 mounting holes 14 Mounting shaft 15 Clamp screw hole 16 Clamp screw 17 Stopper screw hole 18 Stopper screw 18a Head of stopper screw 18 O Drill body 1 axis T drill rotation direction

Claims (3)

[Claims] 1. A tip mounting seat having a concave groove shape is formed at a tip end portion of a substantially columnar drill body which is rotated around an axis line and which is open to a tip end surface of the drill body and extends along a plane including the axis line. A throw-away type drill in which a flat throw-away tip having a cutting edge formed at its tip is detachably attached to the tip mounting seat by a clamp screw that is screwed into the drill main body. Is a throw-away drill, wherein a stopper screw screwed into the drill body can press the clamp screw toward the screwing direction. 2. The drill body is provided with a clamp screw hole into which the clamp screw is screwed and a stopper screw hole into which the stopper screw is screwed, the opening portions communicating with each other, and the stopper screw hole being formed adjacent to each other. Is provided with a head portion, and by screwing the stopper screw into the stopper screw hole, the clamp screw is pressed by the head portion toward the screwing direction side. Formula drill. 3. The throw-away drill according to claim 2, wherein the stopper screw hole is formed adjacent to the clamp screw hole in the axial direction.