JP2001347504A - Tipped-blade router bit having end cutting edge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tipped-blade router bit having an end cutting edge wherein a cutting resistance in thrust-in processing in cutting is lightened, and discharge of chips is simultaneously improved to raise a processed quality. SOLUTION: A cylindrical main body 1 is divided into an edge part 1a and a shank part 1b, and 2-4 lines of chips-discharging grooves 1c and 1c' and the like are provided at the edge part 1a to form an edge base 1d. A hard tip 2 is bonded to the edge base 1d, a peripheral cutting edge 2c is formed at the peripheral side of the hard tip 2, and an end cutting edge 2e is formed at an end part side. An end cutting edge 1g is formed in an edge part of the main body 1 at 30 deg. positive rake angle from 0 deg. to a rotary center 0 of the main body 1 by allowing it to continue to the end cutting edge 2e.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a router bit used for performing an end milling process or a hole drilling process on a work material in the fields of wood, board, decorative board and the like. More specifically, the present invention relates to a cutting edge router bit having a bottom cutting edge which can be easily pierced from the surface of a work material.

[0002]

2. Description of the Related Art FIGS. 9 to 11 show, for example, a prior art (A) of a cutting edge router bit having a bottom cutting edge. In this example, the one end of the router bit is a shank portion 101A and the other end is a blade portion 101B.
Are formed with two axial chip discharge grooves 101a on the outer peripheral cylindrical surface of. And each of the chip discharge grooves 10
1a, the hard tip 102 is joined in the axial direction,
An outer peripheral cutting edge 102 is provided on the outer peripheral side of each hard tip 102.
a is formed, and a bottom cutting blade 102b is formed on the tip side. The bottom cutting blade 102b has a blade portion 101B within the range of the chip width.
And the bottom cutting edge does not exist near the center of rotation.

The shaft end of the main body shaft 101 is formed in a roof shape as shown in FIG. 11, and the roof ridge 101b has an apex angle of about 80 degrees. The roof ridge 101b is not formed as a regular cutting blade, but when the router bit is pierced into the work material, the roof ridge 101b has a bottom rake angle of about -40 degrees so as to press the chips. And acts as a bottom cutting edge to cut the work material.

FIGS. 12 and 13 show another conventional router bit (B). This router bit has a shank 111A at one end and a blade 111 at the other end.
As B, two axial chip discharge grooves 111a and 111b are cut on the outer peripheral cylindrical surface of the blade portion 111B. One of the chip discharge grooves 111a has a groove depth a having a radial dimension from the outer periphery to the rotation center position O in the vicinity of the tip, and the hard chip 1 having a width of the radius dimension a over the entire groove depth a.
12 are joined. At the tip of the hard tip 112, a bottom cutting edge 112a from one peripheral point to the rotation center position O is formed.

[0005] The other chip discharge groove 111b is provided shallowly near the outer periphery, and has a hard chip 113 having a groove depth in the axial direction.
Is joined parallel and away from the hard tip 112,
An outer peripheral cutting edge 113 a is formed on the outer peripheral side of the hard tip 113. The hard tip 113 has a bottom cutting edge 11 at its tip.
3b, the bottom cutting edge 113b is
The rotation center position O does not reach the first rotation center position O, and the bottom cutting edge is interrupted without being continuous from one point on the outer periphery to another point on the opposite side.

[0006]

When the router bit of the prior art (A) described in the prior art is pierced into a work material in order to carry out a hollowing operation or a punching hole expanding operation, the blade portion 101 is cut.
In the vicinity of the center of rotation of the end portion B, there is a problem that the cutting resistance is high because there is no regular bottom cutting edge, and the cutting edge becomes a negative bottom rake angle so that the cutting performance is poor. Further, there is a problem that the work material may be burned depending on the material of the work material and the processing conditions.

Further, in the router bit of the prior art (B), there is only one bottom cutting edge 112a formed by the hard tip 112 which reaches the center of rotation.
13b generates a small amount of chips, and the bottom cutting edge 1
Most of the chips generated in 12a are a single chip discharge groove 111.
a, and there is a problem that chips exceeding the processing capacity block the chip discharge grooves 111a. In addition, there is a problem that a large cutting power is required due to clogging of chips, and burns are generated.

In order to eliminate the clogging of chips,
Although the plunging speed has to be reduced, there is a problem in that the working efficiency is reduced. In addition, since the bottom cutting edge is not arranged point-symmetrically with respect to the center of rotation, the cutting force acts in a non-uniform manner, making it impossible to perform correct drilling. The present invention has been made in view of the above problems, and an object of the present invention is to provide a bottom cutting edge that reduces cutting resistance at the time of piercing in cutting, and at the same time improves chip quality by improving chip discharge. It is intended to provide a cutting edge router bit.

[0009]

According to a first aspect of the present invention, there is provided a router bit according to the present invention, comprising a cylindrical main body, one end of which is divided into two parts, a blade and a second end. Side is a shank portion, and the same number of blade bases are formed by providing two to four chip discharge grooves in the blade part, and a hard tip is joined to the blade base to form a blade body, and an outer peripheral side of the hard tip An outer peripheral cutting edge is formed on the end side, and a bottom cutting edge extending from a position substantially continuous with the bottom cutting edge of each hard tip to the center of rotation of the main body or near the center is set to a positive bottom rake angle of 0 to 30 degrees. It is formed at the end of the main body.

According to the router bit of the present invention, since the bottom cutting edge is formed almost continuously to the bottom cutting edge of the hard tip and at the end of the main body to the vicinity of the center of rotation, 2 to 4 is provided from the outer periphery to the vicinity of the center of rotation. Will extend. The bottom cutting edge of the main body is provided with a positive bottom rake angle of 0 to 30 degrees, not negative, so that cutting resistance is reduced at the time of piercing the work material. Further, since the chips are dispersed in the respective cutting discharge grooves, the chip discharge grooves are smoothly discharged without being clogged, and therefore, the processing quality of the inner surface of the hole is improved. In addition, since the cutting is performed by using 2 to 4 bottom cutting edges, the cutting force is not biased and does not act on the router bit, so that a correct hole can be processed, and the processing quality can be improved. Further, the cutting power is reduced by reducing the cutting resistance. In addition, since the bottom rake angle of the bottom cutting edge is set to 0 to 30 degrees, the sharpness during cutting is improved without impairing the strength of the bottom cutting edge.

According to a second aspect of the present invention, there is provided a router bit according to the present invention, wherein each of the hard tip bottom cutting edges and the bottom cutting edge at the end of the main body are connected in a V shape. Claim 2
According to the router bit, since the bottom cutting edge of the hard tip and the bottom cutting edge at the end of the main body are formed in a V shape, chips by the hard tip are not discharged so as to be pushed out in the outer peripheral direction. Since the material is discharged in such a direction as to be collected inside the main body, it is possible to obtain a good finished surface without causing the cutting inner surface of the work material to be damaged by the chips.

According to a third aspect of the present invention, there is provided a router bit according to the present invention, wherein the cutting edge is inclined with respect to the axis of the main body, and the hard cutting tip is joined to the cutting edge by cutting. With a positive bottom rake angle. Claim 3
According to the router bit, in addition to the bottom cutting edge at the end of the main body, the bottom cutting edge of the hard tip was given a positive, not negative, rake angle, further reducing cutting resistance and improving sharpness. The finished surface is good. In addition, the cutting power is reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a front view of a router bit according to the present invention, and FIG.
2 is an enlarged view of FIG. 1B. The main body 1 of the router bit has a columnar shape, and is made of cemented carbide or tool steel. The main body 1 is divided into two parts. In FIG. 1 (a), one end of the left half is a blade portion 1a actually involved in cutting, and the other end of the right half is a shank portion 1b to be mounted on a machine (not shown). . In the blade portion 1a, two chip discharge grooves 1c, 1c 'are cut in the outer peripheral axis direction at positions symmetrical with respect to the rotation center O of the main body 1. And the blade 1a
Has a Z-shaped cross section perpendicular to the axis due to the cutting of two chip discharge grooves 1c and 1c '.

The chip discharge groove 1c will be described below, but the same applies to the chip discharge groove 1c '. The wall surface of the chip discharge groove 1c corresponding to the parallel side of the Z-shape becomes the blade base 1d, and extends in the axial direction to braze the hard tip 2 with the end 2a slightly projecting from the tip 1e of the main body 1. To form a blade body. The material of the hard tip 2 is a cemented carbide, a sintered diamond, a borazon, or the like. An outer peripheral flank 2b having an outer peripheral clearance angle θa and an outer peripheral cutting edge 2c are formed on the hard tip 2 along the outer peripheral surface of the cylindrical portion of the blade portion 1a of the main body 1. Also, a bottom flank 2d having a bottom blade clearance angle θb is cut at the end 2a of the hard tip 2 so that the bottom cutting blade 2e is formed.
Are formed. However, since the hard tip 2 is joined parallel to the axis of the rotation center O of the main body 1, the bottom cutting edge 2
The bottom rake angle αa of e is 0 degree. Therefore the bottom rake angle α
a cannot be shown. At this time, the center-side end 2 of the bottom cutting edge 2e
The position f is set so as to be retracted to the rear of the rotation direction of the router bit indicated by the arrow with respect to a straight line P connecting the rotation center position O of the main body 1 and the end position of the outer peripheral cutting edge 2c of the hard tip 2. Is formed.

At the end 1e of the blade portion 1a, a straight line connecting the inside position 2f of the bottom cutting blade 2e of the hard tip 2 and the rotation center position O of the main body 1 is a roof ridge, and both roof surfaces 1f are slightly inclined. It flows on both sides with it. The end 1e is set to the main body 1 so that the roof ridge is the bottom cutting edge 1g of the blade 1a of the main body 1.
At a predetermined angle to the roof ridge at the rotation center position O
From the roof ridge and the axis center line, the slope 1 is sharply inclined in the direction of the shank portion 1b toward the chip discharge groove 1c to cut the roof surface 1f on one side and to flow the chips.
form i. With this vertical surface 1h, the roof ridge becomes a bottom cutting edge 1g. Therefore, in the vicinity of the center, the shaving amount is small, and the shaving amount becomes maximum at the point 2f inside the bottom cutting edge 2e. . At this time, since the bottom cutting edge 1g of the roof ridge is formed so as to be continuous with the bottom cutting edge 2e of the hard tip 2, the bottom rake angle αb of the bottom cutting edge 1g is formed at 0 degree as a non-negative angle. . Therefore, the bottom rake angle αb cannot be shown.

The two bottom cutting edges 1g and 2e thus formed are located at positions retracted from the straight line P, and the bottom cutting edge 1g
And the bottom cutting edge 2e are bent and extended in a U-shape and are formed continuously. The angle between the straight line P and the bottom cutting edge 2e is the outer peripheral cutting edge 2
is the positive outer edge rake angle αc given to c, and is involved in the sharpness of the inner peripheral surface when drilling and expanding holes. The rake angle αc of the outer peripheral blade is usually 8 degrees or more.
30 degrees.

[Operation] An operation will be described for a case where a hole is formed in a work material by the router bit. When the router bit is rotated and approached to the work material, first, the bottom cutting edge 2e of the hard tip 2 whose end 2a slightly protrudes from the front end 1e of the main body 1 contacts the work material, and Start to cut the wood. Therefore, the work material is cut into a ring shape by the bottom cutting edge 2e, but the cutting at this time is performed by the chip discharge grooves 1c, 1c.
It is discharged immediately regardless of '. Immediately after that, the bottom cutting edge 1g of the main body 1 comes into contact with the work material by the advancement of the router bit, and cutting is performed. From the outer periphery of the router bit to the center of rotation O of the main body, the bottom cutting edge 2e of the hard tip 2 and the bottom cutting edge 1g of the main body 1
Are continuously extended, so that a hole having a diameter of a router bit is formed in a work material smoothly with low cutting resistance.

Since the bottom cutting edge 1g of the main body 1 and the bottom cutting edge 2e of the hard tip 2 are shaped like a letter that recedes in the rotational direction, chips generated by the bottom cutting edge 2e of the hard tip 2 are directed outward. The chips are not discharged so as to be pushed out, but are fed into the chip discharge grooves 1c and 1c 'in such a direction as to be collected inside the main body 1. Chips formed by the bottom cutting edge 1g of the main body 1 are sharply inclined and cut along the steep slope 1i.
c, 1c '.

The chips shaved by the two bottom cutting blades 2e and 1g in this way are discharged outside through the chip discharge grooves 1c and 1c '. As the cutting progresses, the inner surface of the hole of the work material is finished by the outer peripheral cutting edge 2c of the hard tip 2 and becomes a good finished surface. After completion of the hole processing, the router bit is moved in a direction perpendicular to the axis without drawing out the router bit from the hole as necessary, and the hole is expanded to a desired shape. In this case, only cutting by the outer peripheral cutting edge 2c is performed. In the above description, the case where two chip discharge grooves are provided is described. However, the chip discharge grooves are equally divided on the outer circumference of the router bit.
Articles and many articles are possible.

[Embodiment 2] Next, Embodiment 2 of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. However, the same portions in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the first embodiment, the bottom cutting edge 1g of the main body 1 is continuous with the bottom cutting edge 2e of the hard tip 2 parallel to the axis of the main body 1. For this reason, the bottom cutting edge was inevitably a bottom rake angle of 0 degree.

In the second embodiment, as shown in FIG. 5, the bottom cutting edge 1j of the main body 1 is provided on a straight line P connecting the end position of the outer peripheral cutting edge 2c of the hard tip 2 and the rotation center O. Therefore, the tool main body 1 does not interfere with the blade base 1d when the bottom cutting edge 1j is formed, and the bottom cutting edge 1j is shown in FIG. 5 up to a straight line connecting the rotation center O and the center end 2f of the bottom cutting edge 2e. In the range of the hatched portion 1k, the blade portion 1a can be cut into the shank portion 1b side, and a non-negative positive bottom rake angle αd can be given as shown in FIG. 4c. The positive bottom rake angle αd can be appropriately used in the range of 0 to 30 degrees. If the angle exceeds 30 degrees, the strength of the bottom cutting edge 1j is weakened, which is unfavorable in design.

[Effect] When end milling or punching is performed using this tool, the main body 1 is inserted into the work material.
The cutting by the bottom cutting edge 1j reduces cutting resistance and improves sharpness. Also in this case, since the hard tip 2 is joined parallel to the axis of the main body 1, the bottom rake angle αa with respect to the bottom cutting edge 2e is 0 degree. Therefore, the bottom rake angle αa cannot be shown.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. However, the same parts as in the first and second embodiments are denoted by the same reference numerals, and the description is omitted.
In the first and second embodiments, the chip discharge groove 1 cut into the main body 1
c and 1c 'were cut in parallel to the axis of the main body 1, and the blade rest 1d was also parallel to the axis of the main body 1. Therefore, the hard tip 2 is also brazed in parallel. Therefore, the bottom rake angle αa of the bottom cutting edge 2e at the end of the hard tip 2 was 0 degree.

In the third embodiment, the main body 1 is similar to the second embodiment.
Is given a positive rake angle αd. Further FIG.
As shown in (c), the chip discharge grooves 1m and 1m 'are formed by twisting with respect to the axis of the main body 1 and have a blade base 1n having a wall surface corresponding to a Z-shaped parallel side having a cross section perpendicular to the axis. The surface is cut and inclined with respect to the axis. For this reason, the hard tip 2 is brazed while being inclined with respect to the axis of the main body 1, and the bottom cutting edge 2 e of the hard tip 2 is given a positive bottom rake angle αe.

[Operation] In the router bit of the third embodiment, the positive bottom rake angles αd and αe are given to all the bottom cutting blades 1j and 2e, so that the cutting resistance is greatly reduced when plunging into the work material. The sharpness further increases. Since the hard tip 2 is brazed obliquely, a lateral rake angle (torsion angle) is given to the outer peripheral cutting edge 2c, and the efficiency of hole expansion after drilling is improved.

[0026]

Since the router bit of the present invention is configured as described above, the following effects can be obtained. In the router bit according to the first aspect, the bottom cutting edge is formed at the end of the main body to the vicinity of the center of rotation so as to be substantially continuous with the bottom cutting edge of each hard chip joined to each of the two to four chip discharge grooves provided on the main body. I let you
Two to four bottom cutting blades extend from the outer periphery to the vicinity of the rotation center. The bottom cutting edge of the main body is not negative, but has a positive bottom rake angle of 0 to 30 degrees, so that cutting resistance is reduced at the time of piercing into a work material. Further, since the chips are dispersed in the respective chip discharge grooves, the chip discharge grooves are smoothly discharged without being clogged, so that the machining quality of the inner surface of the hole is improved.

Further, since the cutting is performed by using 2 to 4 bottom cutting blades, the cutting force is not biased and does not act on the router bit, so that the correct drilling can be performed and the processing quality can be improved. Further, the cutting power is reduced by reducing the cutting resistance. In addition, since the bottom rake angle of the bottom cutting edge is set to 0 to 30 degrees, the sharpness during cutting is improved without impairing the strength of the bottom cutting edge.

In the router bit of the present invention, since the bottom cutting edge of the hard tip and the bottom cutting edge of the end of the main body are formed in a V shape, the chips by the hard tip are discharged so as to be pushed out in the outer peripheral direction. It is discharged in such a direction as to be collected inside the main body, so that a good finished surface can be obtained without damaging the cut inner surface of the work material by cutting.

In the router bit according to the third aspect, the bottom cutting edge of the hard tip in addition to the bottom cutting edge at the end of the main body is provided with a positive, not negative, rake angle, so that the cutting resistance is further reduced. Further, the sharpness is improved and the finished surface is improved. In addition, the cutting power is reduced.

[Brief description of the drawings]

FIG. 1 is an overall explanatory view of a router bit according to a first embodiment of the present invention, where (a) is a front view, (b) is a view taken along the line AA of (a), and (c) is a view of (b). BB cross-sectional view, (d) is a view taken in the direction of arrow CC in (b), (e) is a view in the direction of arrow DD in (d), (f)
(E) is an EE arrow view of (e).

FIG. 2 is an enlarged view of FIG.

FIG. 3 is a perspective view of Embodiment 1 of the present invention.

FIG. 4 is an overall explanatory view of a second embodiment of the present invention, wherein (a)
FIG. 3B is a front view, FIG. 4B is a view taken along the line FF in FIG. 3A, and FIG. 3C is a view taken along the line GG in FIG.

FIG. 5 is an enlarged view of FIG. 4 (b).

FIG. 6 is a perspective view of a second embodiment of the present invention.

FIG. 7 is an overall explanatory diagram of a third embodiment of the present invention, wherein (a)
FIG. 3B is a front view, FIG. 3B is a view taken along the line HH in FIG. 3A, and FIG. 3C is a view taken along the line JJ in FIG.

FIG. 8 is a perspective view of a third embodiment of the present invention.

FIG. 9 is an explanatory diagram of the entire router bit of the conventional example (A).

FIG. 10 is a view taken along the line KK of FIG. 9;

FIG. 11 is a front view of the blade section taken along the line LL in FIG. 10;

FIG. 12 is an explanatory diagram of the entire router bit of the conventional example (B).

FIG. 13 is a view taken along the line MM in FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 1a Blade part 1b Shank part 1c, 1c 'Chip discharge groove 1d Blade base 2 Hard tip 2c Peripheral cutting blade 2e, 1g Bottom cutting blade O Rotation center αb, αd rake angle at bottom

Claims (3)

[Claims] 1. A main body having a cylindrical shape, one end of which is divided into two, a blade, and the other end is a shank.
The same number of blade bases are formed by providing up to four chip discharge grooves, and a hard tip is joined to the blade base to form a blade body, and an outer peripheral cutting edge is bottom-cut at an outer peripheral side of the hard chip at an end side. A blade is formed, and a bottom cutting edge extending from a position substantially continuous to a bottom cutting edge of each hard tip to a center of rotation of the main body or near the center is formed at an end of the main body at a positive bottom rake angle of 30 degrees from 0 degrees. A cutting edge router bit having a bottom cutting edge. 2. The cutting edge router bit having a bottom cutting edge according to claim 1, wherein the bottom cutting edge of each hard tip and the bottom cutting edge at the end of the main body are connected in a V shape. 3. A positive bottom rake angle for the bottom cutting edge of the hard tip to be joined to the blade base by cutting and tilting the surface serving as the blade base with respect to the axis of the main body by providing a twist. A cutting edge router bit having a bottom cutting edge according to claim 1 or 2, wherein the cutting edge is provided.