JP4400178B2 - Drill - Google Patents

Description

  The present invention relates to a drill used for drilling for forming a machining hole in a work material.

Conventionally, a pair of chip discharge grooves extending toward the rear end side are formed on the outer periphery of the cutting edge part, which is the tip side part of the drill body rotated about the axis, and a pair of cutting edges are provided at the tip of the cutting edge part. Drills are known.
In general, a drill body in such a drill has a pair of cutting fluid supply holes drilled from the rear end side to the tip, and the pair of supply holes opens at the tip surface of the cutting edge portion. It is made to open so that it may have a part (for example, refer to patent documents 1). During drilling, the cutting oil and the bottom of the machining hole are lubricated and cooled by discharging and supplying the cutting oil from the opening to the tip surface of the cutting oil supply hole. The chips generated in step 1 are pushed out into the chip discharge groove and discharged.
JP-A-9-136206

However, in the conventional drill, since the supply hole of the cutting fluid is opened at the tip surface of the cutting edge part, the cutting edge part to which a large cutting resistance is applied is equivalent to the supply hole being bored inside. There was a problem that the strength of the tip portion was lowered.
In particular, such a decrease in strength at the tip of the blade tip is a problem because a tip having a cutting edge is detachably attached to a concave groove-shaped tip mounting seat that opens at the tip surface of the blade tip. The tip of the cutting edge is attached to the drill with the cutting edge provided at the tip of the cutting edge, or the tip having a cutting edge is attached to the tip mounting seat that opens at the tip of the cutting edge by brazing. This is the case in which a tip mounting seat is formed at the tip portion of the blade tip portion, and the cross-sectional area of the tip portion of the blade tip portion inevitably becomes small like a drill having a cutting edge at the tip. .

That is, the amount of cutting oil applied to the inside of the tip portion of the blade edge portion is reduced by the amount the tip mounting seat is formed at the tip portion of the blade edge portion, although the sectional area of the tip portion of the blade edge portion is reduced. If the supply hole is drilled and opened at the tip surface, the cross-sectional area is further reduced, and the strength of the blade edge portion is further reduced. Such a tendency of strength reduction at the tip portion of the cutting edge portion becomes remarkable particularly in the case of a small-diameter drill.
The present invention has been made in view of the above problems, and a drill that does not reduce the strength of the tip portion of the cutting edge portion despite the fact that a cutting fluid supply hole is drilled in the drill body. The purpose is to provide.

In order to solve the above problems and achieve such an object, the present invention provides a chip discharge extending toward the rear end side on the outer periphery of the cutting edge portion which is the front end side portion of the drill body rotated about the axis. In the drill in which a groove is formed and a cutting edge is provided at the tip of the cutting edge portion, a cutting oil supply hole is drilled in the drill body from the rear end side to the tip, and the supply hole Is opened so as to have an opening on the outer peripheral surface of the blade edge portion, and a groove-shaped tip mounting seat that opens at the front end surface of the blade edge portion and is recessed toward the rear end side is formed in a diameter direction with respect to the axis. A cutting edge is provided at the tip of the cutting edge by attaching a flat tip having a cutting edge formed at the tip to the tip mounting seat. The opening of the supply hole Than the bottom facing the distal end side of the seat has been is positioned on the rear side, the outer peripheral surface of the cutting edge portion of the opening of the supply hole up to the front end surface of the edge portion is cut in a groove shape A supply groove is formed, and the supply groove extends substantially linearly while being inclined toward the rear side in the drill rotation direction from the rear end side toward the front end .

According to the present invention, the cutting fluid supply hole is not opened in the front end surface of the cutting edge portion, but is opened in the outer peripheral surface of the cutting edge portion at a position separated from the front end surface of the cutting edge portion by a predetermined distance from the rear end side. Therefore, the strength of the tip portion of the blade edge portion is not lowered.
In particular, a recessed groove-shaped tip mounting seat that opens at the front end surface of the blade tip portion and is recessed toward the rear end side is formed to extend in the diameter direction, and a tip having a cutting edge is attached to the tip mounting seat. In the case where the strength has been lowered by the amount that the tip mounting seat is formed at the tip portion of the blade edge portion, such as a drill having a cutting edge provided at the tip of the blade edge portion. By effectively positioning the opening of the supply hole on the rear end side with respect to the bottom surface facing the front end side of the tip mounting seat , the effect of suppressing the strength reduction of the front end portion of the blade edge portion is effectively obtained. Can do.

Here, when the cutting fluid supply hole is opened on the outer peripheral surface of the cutting edge portion as described above, cutting is performed from the opening to the outer peripheral surface of the cutting edge portion in the cutting fluid supply hole at the time of drilling. Even if the oil agent is discharged and supplied, it becomes difficult to lubricate and cool the cutting edge and bottom of the machining hole, or to push the chips generated by the cutting blade into the chip discharge groove and discharge them. It is possible that
Therefore, in the drill of the present invention, the outer peripheral surface of the cutting edge portion of the opening of the supply hole up to the front end surface of the cutting edge portion that is formed is supplied groove made by cutting in a groove shape. With such a configuration, the cutting fluid discharged from the opening of the supply hole is surely guided to the tip surface of the cutting edge through the supply groove, and lubrication / cooling of the cutting edge and the bottom of the machining hole, or chip removal The discharge can be performed reliably.
Further, since the supply groove extends in a substantially straight line while being inclined toward the rear side in the drill rotation direction from the rear end side to the front end side , the cutting oil contained in the supply groove is allowed to flow into the drill body. With rotation, it can be reliably guided to the tip surface of the blade edge part.

First, a drill according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
As shown in FIGS. 1 and 2, the drill body 10 of the drill according to the first embodiment is such that the cutting edge portion 12 that is the tip side portion is reduced in diameter by one step with respect to the shank portion 11 that is the rear end side portion. A substantially multi-stage cylindrical shape centering on the axis O rotated about the axis O is formed.
On the outer periphery of the blade edge portion 12, a pair of chip discharge grooves 14 and 14 that open to the tip surface 13 are positioned on opposite sides of the axis O, and the drill rotates as it moves toward the rear end in the direction of the axis O. It is formed so as to extend to the rear end side in a spiral shape so as to be twisted rearward in the direction T.

Further, a concave groove-shaped tip mounting seat 15 that opens to the front end surface 13 and is recessed toward the rear end side is formed at the front end of the blade edge portion 12 so as to extend in the diameter direction with respect to the axis O. A chip 20 having a substantially pentagonal flat plate shape with a pair of cutting blades 21 and 21 formed at the tip thereof is detachably mounted on the chip mounting seat 15 by a clamp screw 16.
As a result, a pair of cutting blades 21 and 21 that are located on opposite sides of the axis O and have a predetermined tip angle are provided at the tip of the blade edge portion 12.

The drill body 10 is provided with a cutting oil supply hole 30 extending along the axis O from the rear end side in the axis O direction toward the tip and having a substantially circular cross section perpendicular to the axis O. ing.
The supply hole 30 is branched into two on the rear end side in the axis O direction with respect to the chip mounting seat 15, and the branched supply holes 30 </ b> A and 30 </ b> A have diameters as they approach the front end side in the axis O direction. The cutting edge portion 12 is defined between a pair of chip discharge grooves 14, 14 extending in the circumferential direction and adjacent in the circumferential direction (circumferential direction around the axis O of the drill body 10, drill rotation direction T). The outer peripheral surface 12A is opened to have openings 31, 31 respectively.

The opening 31 of the supply hole 30 (30A) is positioned on the outer peripheral surface 12A of the blade edge portion 12 at a position separated from the tip surface 13 of the blade edge portion 12 by a predetermined distance. The portion 31 is positioned on the rear end side in the direction of the axis O of the bottom surface 15A facing the tip side in the direction of the axis O of the groove-shaped chip mounting seat 15 to which the chip 20 is attached.
The branched supply holes 30 </ b> A and 30 </ b> A and the openings 31 and 31 are arranged so as to be rotationally symmetric with respect to the axis O of the drill body 10.

  Further, the outer peripheral surface 12A of the blade edge portion 12 is cut out in a groove shape from the opening portion 31 of the supply hole 30 to the tip surface 13 of the blade edge portion 12, so that the tip surface 13 of the blade edge portion 12 and A concave groove-shaped supply groove 32 is formed that opens to the opening 31 of the supply hole 30 and extends substantially linearly along the axis O direction.

The drill according to the first embodiment having the above-described configuration is applied to the work material by the drill main body 10 being fed around the axis O while being fed toward the tip side in the direction of the axis O. Drilling is performed, and chips generated by the cutting blades 21 and 21 are discharged toward the rear end side in the chip discharge grooves 14 and 14 while being curled by the inner wall surfaces of the chip discharge grooves 14 and 14. By doing so, drilling is continued.
At the time of drilling, the cutting oil 21 and 21 and the machining hole are supplied by discharging and supplying the cutting oil from the openings 31 and 31 to the outer peripheral surface 12A of the cutting edge portion 12 in the cutting oil supply hole 30. Lubrication / cooling of the bottom is performed, and chips generated by the cutting blades 21 and 21 are pushed out into the chip discharge grooves 14 and 14 and discharged.

  In the drill according to the first embodiment as described above, the cutting oil supply hole 30 is not opened in the tip surface 13 of the blade tip portion 12 as in the prior art, but the tip surface 13 of the blade tip portion 12. From the bottom surface 15A of the tip mounting seat 15 to which the tip 20 is attached, particularly at the rear end side in the axis O direction. It is opened so as to have an opening 31 in the position.

As described above, the cutting oil supply hole 30 is formed in the drill main body 10 so as to avoid the portion where the strength tends to be lowered due to the formation of the chip mounting seat 15. The strength of the tip portion of the blade edge portion 12 that has caused a decrease in strength can be sufficiently ensured, and the effect of suppressing the strength reduction of the tip portion of the blade edge portion 12 can be effectively exhibited. .
Therefore, according to the drill of the first embodiment, the strength of the distal end portion of the blade edge portion 12 is not reduced even though the cutting oil supply hole 30 is drilled in the drill body 10. , Stable drilling can be continued. In particular, the drill as in the first embodiment can be expected to have a remarkable effect as the outer diameter of the cutting edge portion 12 becomes smaller.

Further, on the outer peripheral surface 12A of the blade edge portion 12, a supply groove 32 is formed in which a portion from the opening portion 31 of the supply hole 30 to the tip surface 13 of the blade edge portion 12 is notched in a groove shape. Therefore, the cutting oil discharged from the opening 31 of the supply hole 30 is reliably supplied to the cutting edge despite the fact that the opening 31 of the supply hole 30 is disposed on the outer peripheral surface 12A of the cutting edge 12 as described above. It is possible to supply even the tip surface 13 of the portion 12.
That is, the cutting fluid discharged from the opening 31 of the supply hole 30 immediately enters the supply groove 32 and reaches the tip surface 13 of the blade edge portion 12 by being guided by the supply groove 32. Therefore, it is possible to lubricate and cool the cutting blades 21 and 21 and the bottom of the machining hole, and to reliably discharge the chips generated by the cutting blades 21 and 21 into the chip discharge grooves 21 and 21. This makes it possible to continue more stable drilling.

Next, the second embodiment of the present invention shown in FIG. 3 and the third embodiment of the present invention shown in FIG. 4 will be described. The same reference numerals are used for the same parts as the first embodiment described above. The description is omitted.
In common with the drills of the second embodiment and the third embodiment, the supply groove formed by cutting out the portion from the opening 31 of the supply hole 30 to the tip surface 13 of the cutting edge 12 in a groove shape. 32 is inclined to the rear side in the drill rotation direction T as it goes from the rear end side in the axis O direction toward the front end.

  The supply groove 32 in the drill of the second embodiment opens in the tip surface 13 of the cutting edge portion 12 and the opening portion 31 of the supply hole 30, and the drill rotation direction T increases from the rear end side in the axis O direction toward the tip. The supply groove 32 in the drill of the third embodiment opens in the distal end surface 13 of the cutting edge portion 12 and the opening portion 31 of the supply hole 30 while being inclined so as to incline toward the rear side. As it goes from the rear end side in the direction of the axis O toward the tip, it extends spirally while twisting around the axis O so as to go back in the drill rotation direction T.

According to the drills of the second and third embodiments, when the cutting fluid discharged from the opening 31 of the supply hole 30 enters the supply groove 32, the cutting fluid that has entered the supply groove 32 is drilled. As the main body 10 rotates, it is reliably guided to the tip surface 13 of the blade edge portion 12.
Therefore, in the drills of the second and third embodiments, it is possible to perform the lubrication / cooling of the cutting edges 21 and 21 and the bottom of the machining hole, and the discharge of chips generated by the cutting edges 21 and 21 even more reliably. Become.

  In each of the above-described embodiments, the tip 20 having the cutting edges 21 and 21 is detachably attached to the recessed groove-like tip mounting seat 15 that opens to the tip surface 13 of the blade edge portion 12. Although it demonstrated with the drill by which the cutting blades 21 and 21 were provided in the front-end | tip of the blade-tip part 12, it is not limited to this, For example, it has a cutting blade with respect to the chip | tip mounting seat opened to the front end surface of a blade-tip part. Even if the tip is attached by brazing and is a drill having a cutting edge provided at the tip of the cutting edge, the above-described effects can be achieved without any inferiority.

It is a side view showing a drill by a 1st embodiment of the present invention. 1 is a front end view showing a drill according to a first embodiment of the present invention. It is a side view which shows the drill by 2nd Embodiment of this invention. It is a side view which shows the drill by 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drill main body 12 Cutting edge part 12A Outer peripheral surface 13 Tip surface 14 Chip discharge groove 15 Chip mounting seat 15A Bottom surface 20 Tip 21 Cutting blade 30, 30A Supply hole 31 Opening part 32 Supply groove

Claims (1)

In the drill in which a chip discharge groove extending toward the rear end side is formed on the outer periphery of the cutting edge portion which is the tip side portion of the drill body rotated around the axis, and a cutting blade is provided at the tip of the cutting edge portion,
In the drill body, a cutting fluid supply hole is drilled from the rear end side to the tip, and the supply hole is opened so as to have an opening on the outer peripheral surface of the cutting edge portion,
A recessed groove-shaped chip mounting seat that opens to the front end surface of the blade edge portion and is recessed toward the rear end side is formed so as to extend in the diameter direction with respect to the axis line,
A cutting edge is provided at the tip of the cutting edge by attaching a flat tip having a cutting edge formed at the tip to the tip mounting seat,
The opening of the supply hole is positioned on the rear end side of the bottom surface facing the front end side of the chip mounting seat ,
A supply groove is formed in which the outer peripheral surface of the blade edge part from the opening of the supply hole to the tip surface of the blade edge part is cut out in a groove shape,
The said supply groove is extended substantially linearly, inclining so that it may go to a drill rotation direction back side as it goes to a front-end | tip from the rear-end side .

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