JP2004106065A - Rotary cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary cutting tool provided with two holes for feeding cutting liquid or cooling liquid from a shank side to a drill tip by corresponding to lead angles of a plurality of drill blades having the arbitrary lead angles. <P>SOLUTION: A drill body 4 continued to the shank 2 is formed with the plurality of drill edges 12 having the arbitrary lead angles, fitting flutes 10 extending along the lead angles of the respective drill edges 12 to the tip are formed in the respective rear surface centers of the drill edges 12, the fitting flutes 10 are communicated with the two holes 6 and 8 formed in the shank 2, and a hollow tubes 14 are inserted and fixed to the two holes 6 and 8 of the shank 2 and the respective fitting flutes 10 so as to easily provide the two holes 6 and 8 for feeding the cutting liquid or the cooling liquid to the drill edges 12 having the arbitrary lead angles from the shank side to the drill tip. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotary cutting tool, and more particularly, to a rotary cutting tool characterized by forming a flow path through which a cutting fluid and a cooling fluid pass.
[0002]
[Prior art]
Conventionally, among rotary cutting tools used for boring a workpiece such as cast iron, a burnishing drill having a cutting edge for drilling and a cutting edge for reaming in one tool is known.
[0003]
This type of drill is used for drilling, stepping, finishing, and the like of automobile parts, engine parts, and the like, and is used for performing complicated stepping processing at one time.
[0004]
In this burnishing drill, when machining a finished hole, a hole is formed with a drill blade made of cemented carbide or the like, and a smooth inner wall surface is formed by rubbing the inner wall surface of the hole with a guide blade. ing.
[0005]
In recent years, as work materials have become high-grade and cutting conditions have become stricter, drills with holes for passing cooling water through burnishing drills have been used, and end mills and other rotary cutting tools other than burnishing drills have been used. When a deep hole is machined with a drill, a rotary cutting tool having two spiral holes for supplying a cutting fluid to the tip of the cutting edge is indispensable. On the other hand, there is a demand for a drill having a specific lead angle according to the cutting conditions.
[0006]
[Problems to be solved by the invention]
As a method of forming two spiral holes in this kind of rotary cutting tool, a powder kneaded body of high-speed tool steel or the like is extruded into a round bar-shaped material by a press or the like, and then a mandrel having a pair of spiral pins is used. A method of forming two spiral holes with a fixed lead in the round bar material by rotating, or forming two spiral holes in a process of extruding the powder kneaded material into a round bar material by extrusion molding method. Methods and the like are known.
[0007]
Then, a drill 301 as shown in FIG. 4 is manufactured by forming a drill blade and a chip discharge groove by grinding or cutting on the outer periphery of the sintered round bar material having two spiral holes formed therein. .
[0008]
However, since the two spiral holes 302 and 303 formed in the drill 301 are formed at a predetermined fixed lead angle (for example, 30 degrees), the drill is formed at a different lead angle from the two holes 302 and 303. When the blade 305 and the chip discharge groove 306 are processed, there is a risk that the two holes 302 and 303 are broken by the chip discharge groove 306, and therefore, the drill blade 305 having an arbitrary lead angle is processed. Had problems that could not be done.
[0009]
[Problems to be solved by the invention]
Therefore, the object of the present invention is to provide two holes for supplying a cutting fluid or a coolant from the shank side to the tip of the drill, regardless of the angle of the lead angle of the drill blade formed on the outer periphery of the round bar-shaped material. An object of the present invention is to provide a rotary cutting tool that can be easily formed without being broken in the middle of a drill body.
[0010]
[Means for solving the problem]
In order to achieve the above object, the present invention has the following technical means. In other words, using the reference numerals used in the accompanying drawings corresponding to the embodiments of the present invention, two holes 6 and 8 connected to the plurality of drill blades 12 of the drill body 4 are formed in the shank 2 of the round bar-shaped rotary tool material. Rotary cutting tool 1
A plurality of drill blades 12 having an arbitrary lead angle are formed in the drill body 4 connected to the shank 2 and fitted to the center of each of the back surfaces of the drill blades 12 so as to reach the tip along the lead angle of each of the drill blades 12. A groove 10 is formed, and each fitting groove 10 communicates with two holes 6, 8 formed in the shank 2, and a hollow is formed in the two holes 6, 8 of the shank 2 and each fitting groove 10. A rotary cutting tool in which a pipe 14 is inserted and fixed.
According to the above, a plurality of drill blades 12 having an arbitrary lead angle are formed in a drill body 4 connected to a shank 2 of a round bar-shaped rotary tool material. Fitting grooves 10 communicating with the holes 6 and 8 are formed along the lead angles of the drill blades 12, and hollow tubes 14 reaching the tips of the drill blades 12 are respectively inserted and fixed in these fitting grooves 10. I do.
Therefore, two holes for supplying a cutting fluid or a cooling fluid from the shank side to the tip of the drill are provided in the fitting groove 10 formed along the center of each back surface of the plurality of drill blades 12 having an arbitrary lead angle. By inserting and fixing the hollow tube 14 communicating with the two holes 6, 8 formed in the drill blade 12, the drill blade 12 can be easily formed without being broken midway regardless of the lead angle of the drill blade 12.
[0011]
In addition, the present invention provides that the groove depth of each of the fitting grooves 10 is a depth equal to or less than the radius of the hollow tube 14, and the outer circumference of the hollow tube 14 inserted and fixed in each of the fitting grooves 10 is the drill bit. 12 is a rotary cutting tool configured to be located inside twelve rotational diameters.
Therefore, since the groove depth of each fitting groove 10 is formed at a depth equal to or less than the radius of the hollow tube 14, not only the influence on the strength of the drill blade 12 is eliminated, but also the insertion into each fitting groove 10 is performed. Since the outer periphery of the fitted and fixed hollow tube 14 is located inside the rotation diameter of the drill blade 12, the hollow tube 14 does not affect the cutting operation by the drill blade 12.
[0012]
The present invention is also a rotary cutting tool wherein the inner diameter of the hollow tube 14 is at least 0.3 mm or more and is not more than 1/2 of the maximum thickness B of the drill bit.
Therefore, when the fitting groove 10 is formed in the center of each back surface, the minimum flow rate for supplying the cutting fluid or the cooling fluid from the shank 2 side to the tip of the drill is ensured, and the required strength of the drill blade 12 is ensured. Can be.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view showing a half cross section below an axis of a burnishing drill according to the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is a partially enlarged view of the tip of the burnishing drill.
[0014]
1 to 3, reference numeral 1 denotes a burnishing drill as an example of the rotary cutting tool of the present invention. The burnishing drill 1 is obtained by molding a powder kneaded body of a cemented carbide or the like by pressing. In this case, a shank 2 is formed of a round bar-shaped rotary tool material formed by sintering after half-firing and forming, and a drill body 4 connected thereto. A cutting oil supply hole 5 communicating with the end of the shank 2 and two holes 6 and 8 communicating from the cutting oil supply hole 5 to the back surface of each of the drill blades 12 described later are formed symmetrically and parallel to the drill axis. Is established.
[0015]
The drill body 4 is formed with two drill blades 12 having a predetermined lead angle (for example, a rightward twist angle of 10 degrees), and a slightly larger diameter reamer blade is connected behind the drill blade 12. (Not shown).
[0016]
As shown in FIGS. 2 and 3, a substantially semicircular cross-section is formed at the center of each back surface 12A of the drill blade 12 so as to have a minimum depth reaching the drill tip along the lead angle of each of the drill blades 12. A mating groove 10 is formed, and each of these fitting grooves 10 is formed so as to communicate with the open ends of two holes 6 and 8 formed in the shank 2.
[0017]
Then, after inserting each end of the cylindrical hollow tube 14 into the open ends of the two holes 6 and 8 formed in the shank 2, and after inserting the respective ends into a pair of fitting grooves 10 reaching the tip, It is fixed by bonding or brazing.
[0018]
In this case, the hollow tube 14 having an inner diameter of at least 0.3 mm or more is used, and is formed to be 1/2 or less of the maximum thickness B of the drill blade 12.
[0019]
Further, the depth of each fitting groove 10 formed at the center of each back surface 12A of the drill blade 12 is preferably a depth equal to or less than the radius of the hollow tube 14, and a pair of the fitting grooves 10 inserted and fixed in the fitting groove 10 are fixed. The outermost periphery between the hollow pipes 14 is located inside the rotation diameter of the drill blade 12, and is configured such that a clearance is formed with respect to the rotation diameter.
[0020]
Therefore, when finishing the deep hole, for example, using the burnishing drill 1, the cutting fluid or the cooling fluid supplied through the cutting oil supply hole 5 and the two holes 6, 8 formed in the shank 2 is medium. Since the swarf is ejected from the tip of the drill through the empty tube 14, the swarf generated by the finishing process is discharged to the outside through the swarf discharge groove 16 together with the cutting fluid or the cooling fluid.
[0021]
That is, according to the burnishing drill 1 configured as described above, the fitting groove 10 communicating with the two holes 6 and 8 formed in the shank 2 is formed in the center of each back surface 12A of the plurality of drill blades 12. By inserting and fixing the hollow pipes 14 communicating with the two holes 6 and 8 in the fitting grooves 10, the two holes 6 and 8 are formed halfway regardless of the lead angle of the drill blade 12. It can be easily formed without breaking.
[0022]
Further, since the groove depth of each fitting groove 10 is formed at a depth equal to or less than the radius of the hollow tube 14, not only does it have no effect on the strength of the drill blade 12, but also it is inserted into each fitting groove 10. Since the outer periphery of the fixed hollow tube 14 is located inside the rotation diameter of the drill blade 12, the hollow tube 14 does not affect the cutting operation by the drill blade 12.
[0023]
Furthermore, when the inner diameter of the hollow pipe 14 is at least 0.3 mm or more and is formed to be 1/2 or less of the maximum thickness B of the drill blade, cutting is performed when the fitting groove 10 is formed at the center of each back surface. A minimum flow rate for supplying a liquid or a cooling liquid from the shank side to the tip of the drill is guaranteed, and the strength of the drill blade 12 can be secured.
[0024]
【The invention's effect】
As described in detail above, the present invention has the following effects.
[0025]
That is, according to the first aspect, a fitting groove is formed at the center of the back surface of each of the plurality of drill blades so as to communicate with the two holes formed in the shank and reaches the drill tip along the lead angle of each drill blade. By inserting and fixing the hollow tube communicating with the two holes formed in the shank in the fitting groove, the two holes are easily formed without being broken in the middle of the drill body regardless of the angle of the lead angle of the drill blade. can do.
[0026]
According to the second aspect, since the depth of each fitting groove is formed to be less than the radius of the hollow tube, not only the influence on the strength of the drill bit is eliminated, but also each fitting groove is formed. Since the outer periphery of the hollow tube inserted and fixed in the hole is configured to be located inside the rotation diameter of the drill blade, the hollow tube does not affect the cutting operation by the drill blade.
[0027]
According to the third aspect, when the inner diameter of the hollow tube 14 is at least 0.3 mm or more and a fitting groove is formed at the center of each back surface, a cutting fluid or a cooling fluid is supplied from a shank side to a drill. The required strength of the drill blade can be ensured by ensuring the minimum flow rate to be supplied to the tip and by forming the inner diameter of the hollow tube 14 to be 1/2 or less of the maximum thickness B of the drill blade 12.
[Brief description of the drawings]
FIG. 1 is a side view showing a half cross section below an axis of a burnishing drill according to an embodiment of the present invention.
FIG. 2 is a view taken in the direction of arrow A in FIG.
FIG. 3 is a partially enlarged view of a tip of a burnishing drill.
FIG. 4 is a side view of a conventional drill in which two holes are formed.
[Explanation of symbols]
1 Burnishing drill (rotary cutting tool)
2 Shank 4 Drill body 5 Cutting oil supply hole 6, 8 2 Hole 10 Fitting groove 12 Drill blade 12A Back surface 14 Hollow tube 16 Chip discharge groove B Maximum drill blade thickness

Claims (3)

In the rotary cutting tool 1 in which two holes 6 and 8 connected to the plurality of drill blades 12 of the drill body 4 are formed in the shank 2 of a round bar-shaped rotary tool material,
A plurality of drill blades 12 having an arbitrary lead angle are formed in the drill body 4 connected to the shank 2 and fitted to the center of each of the back surfaces of the drill blades 12 so as to reach the tip along the lead angle of each of the drill blades 12. A groove 10 is formed, and each fitting groove 10 communicates with two holes 6, 8 formed in the shank 2, and a hollow is formed in the two holes 6, 8 of the shank 2 and each fitting groove 10. A rotary cutting tool, wherein a pipe 14 is inserted and fixed. The groove depth of each of the fitting grooves 10 is set to a depth equal to or less than the radius of the hollow tube 14. The rotary cutting tool according to claim 1, wherein the rotary cutting tool is configured to be located inside. The rotary cutting tool according to claim 1, wherein an inner diameter of the hollow tube (14) is at least 0.3 mm or more and is formed to be 1/2 or less of a maximum thickness (B) of the drill bit.

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