JPH0453848Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an end mill with a bottom blade, in which chips each having a cutting edge are attached to the outer periphery of the tip and the tip surface of the end mill body. .

[Prior Art] Generally, when performing groove processing or stepped processing on a material to be cut, chips each having a cutting edge are removably attached to the tip of the tool body at positions that are used as a bottom edge and an outer edge. An end mill with a bottom blade (hereinafter abbreviated as an end mill) attached to the machine is used.

FIGS. 12 and 13 show a conventional end mill of this type, and reference numeral 1 in the figures indicates the end mill body of this end mill.

This end mill body 1 has a substantially cylindrical shape with its base end rotatably held around its axis, and each part is located at a position diametrically symmetrical with respect to the axis O on the outer periphery of its tip end. Chip pockets 2a and 2b are formed by cutting out a large portion. Of the wall surfaces forming the tip pockets 2a, 2b, concave tip seats 3a, 3b are formed at the outer peripheral end of the wall surface facing the rotational direction of the end mill body 1, respectively.

Here, one chip seat 3a is formed with one side thereof open on the outer peripheral side of the tip pocket 2a, and the other chip seat 3b is formed at a position biased towards the axis O side of the chip pocket 2b.
Chips 4a and 4b are removably mounted on these chip seats 3a and 3b, respectively.

Each of the chips 4a and 4b has a parallelogram plate shape with a lower surface 5 serving as a seating surface, and the chip 4a mounted on one chip seat 3a has a straight line formed on the ridgeline of its upper surface. The tip 4b has a shaped cutting edge protruding from the outer periphery 1a and the tip surface 1b of the end mill body 1, and is attached to the other tip seat 3b.
are attached to the end mill main body 1 with a linear cutting blade formed on a ridgeline portion of the upper surface thereof protruding from the distal end surface 1b. As a result, the tip 4a is made into a circumferential cutting tip, the cutting edge protruding from the outer periphery 1a of the end mill body 1 is made into the circumferential cutting edge 6, and the cutting edge protruding from the tip surface 1b is made into the bottom cutting edge 7. ing. In addition, the above chip 4b
is an inner circumferential tip, and a cutting edge protruding from the tip surface 1b of the end mill body 1 is a bottom edge 8.

In the end mill configured as described above, the inner circumferential surface of the workpiece is cut by the outer circumferential cutting edge 6 of the outer circumferential tip 4a rotating around the axis O through the end mill body 1, and the outer circumferential tip 4a and The bottom surface of the workpiece is cut with the respective bottom blades 7 and 8 of the inner circumferential tip 4b.

[Problems to be solved by the invention] However, in the conventional end mill described above, the load generated by cutting is applied to the plate-shaped tip 4.
Since the tool acts in the thickness direction between the upper and lower surfaces where the rigidity of the a and 4b is poor, the tool has a disadvantage that the rigidity is poor and the cutting edge is easily damaged, so it cannot be used for heavy cutting. Moreover, since the cutting resistance of these straight outer circumferential cutting edges 6 and bottom edges 7 and 8 is relatively large, chatter and vibration are likely to occur in the entire end mill body 1, resulting in a problem of poor finished surface accuracy. Ta. In addition, this type of linear cutting blade generally has a problem in that its chip discharge performance is poor.

[Purpose of the invention] This invention was made in view of the above circumstances.
The object of the present invention is to provide an end mill that has high tool rigidity so that there is no risk of chipping of the cutting edge even when used for heavy cutting, and that has excellent cutting performance and chip evacuation performance.

[Means for Solving the Problems] The end mill of this invention has cutting blades formed on the ridges of the upper surface of each plate, and nose blades formed on the corners sandwiched by the cutting blades. and the side surface from the cutting edge to the lower surface serving as the seating surface is an inner surface formed by a convex curved surface such that the width between the side surfaces at the center of the cutting edge is larger than each width at both ends of the cutting edge. The circumferential tip and the outer circumferential tip are such that the inner circumferential tip has its lower surface abutted against the tip surface of the end mill body and its cutting edge serves as a bottom edge, so that its side surface serves as a rake surface, while the outer circumferential tip has By turning the upper surface toward the outer circumferential side of the end mill body and making the cutting edge an outer circumferential cutting edge, the side surface becomes a rake surface, and a ridge line is formed on the side surface that intersects with the tip side of the outer circumferential cutting edge. The small cutting blade is attached to the end mill body so as to be continuous with the bottom blade of the inner circumferential tip in the rotation locus.

[Example] Figures 1 to 11 show an example of the end mill of this invention.

In FIGS. 1 to 3, the reference numeral 10 indicates an end mill main body, and this end mill main body 1
Tip pockets 11a and 11b are formed at substantially diametrically symmetrical positions at the tip of the tip. The end mill main body 10 also has a tip seat 13a which is concave on the outer circumferential surface 12 and has one side open to one tip pocket 11b.
A tip seat 15 is formed in the distal end surface 14 and has a concave shape, and one side thereof opens into the other tip pocket 11b. A chip 16 serving as an outer chip is placed on the chip seat 13a, and a chip 1 serving as an inner chip is placed on the chip seat 15.
7 are removably attached via clamp screws 18 and 19, respectively.

Here, the chip 16 which is the outer peripheral chip
As shown in FIGS. 4 to 6, the upper and lower surfaces 20,
21 is a substantially parallelogram-shaped plate-like member, and cutting edges 22, 22 are formed at a pair of opposing ridgeline portions on the longer sides of the ridgeline portions of the upper surface 20 sandwiching an acute angle therebetween. Moreover, cutting edges 23, 23 are formed on a pair of opposing ridgeline portions on the short sides, and chamfers 24, 24 are further provided on the ridgeline portions along these cutting edges 23, 23.

The side surface 25 of this chip 16 from each of the cutting edges 22 to the lower surface 21 serving as a seating surface is as follows:
Side surfaces 25, 25 at the central portion 22a of the cutting blade 22
The width dimension between both ends 22b, 22b of this cutting blade 22
It is formed by a convex curved surface that is larger than each width dimension. Further, a nose blade 2 is provided at the acute angle corner sandwiched between the cutting blade 22 and the cutting blade 23.
6 further extends from this nose blade 26 to the cutting blade 22.
The ridgeline portion of the side surface 25 extending in the direction intersecting the
A small cutting edge 27 is formed respectively. Note that the reference numeral 28 in the figure indicates a mounting hole for fixing the tip 16 to the tip seat 13 of the end mill body 10.

Moreover, the chip 17, which is the inner circumferential chip, is
As shown in FIGS. 7 to 9, the upper and lower surfaces 30, 31
It has a substantially parallelogram-like plate shape with parallel sides, and cutting edges 32, 32 are formed on a pair of opposing ridgeline portions on the longer sides of the ridgeline portions of the upper surface 30 sandwiching an obtuse angle therebetween. Further, cutting edges 33, 33 are formed on a pair of opposing ridgeline portions on the short side, and chamfers 3 are further formed on the ridgeline portions along these cutting edges 33, 33.
4,34 are applied.

The side surface 35 of this chip 17 from each of the cutting edges 32 to the lower surface 31 serving as a seating surface is
Side surfaces 35, 35 at the central portion 32a of the cutting blade 32
The width dimension between both ends 32b, 32b of this cutting blade 32
It is formed by a convex curved surface that is larger than each width dimension. In addition, a nose blade 3 is provided at the obtuse corner sandwiched between the cutting blade 32 and the cutting blade 33.
6 is formed. Note that reference numeral 38 in the figure indicates that this tip 17 is attached to the tip seat 1 of the end mill main body 10.
5 shows a mounting hole for fixing to 5.

The inner peripheral chip 17 has a lower surface 31 thereof.
is brought into contact with the bottom surface of the tip seat 15 so that its cutting edge 32 becomes a bottom edge, and its convexly curved side surface 35 acts as a rake surface. The lever is attached to the end mill body 10.

On the other hand, the outer peripheral chip 16 has its upper surface 20 facing the outer peripheral side at the chip seat 13 and its cutting edge 22 as an outer peripheral cutting edge, so that its side surface 2
5 is considered to be the rake face. Furthermore, as shown in FIG. 10, this chip 16 has a small cutting edge 27 that intersects with the tip 22b side of the cutting edge 22, which is the outer peripheral cutting edge, and a bottom cutting edge of the inner peripheral chip 17. It is attached to the end mill main body 10 via a clamp screw 18 inserted into a mounting hole 28 so as to be continuous with the blade 32 in the rotation locus.

Here, as shown in FIGS. 10 and 11, these outer circumferential tips 16 and inner circumferential tips 17 have a small cutting edge 27 and a cutting edge 32, which are respectively bottom edges, from the axis O of the end mill body 10. They are mounted so as to be inclined at an angle α and an angle θ, respectively, with respect to a plane orthogonal to the axis O in the outer circumferential direction.

However, for such end mills,
Since both the outer circumferential tip 16 and the inner circumferential tip 17 are mounted with their side surfaces 25, 35 as rake surfaces each formed into a convex curved surface, the load generated by cutting is transferred to the highly rigid side surfaces 25, 25, 3, respectively.
You can receive it between 5 and 35. Therefore,
Since high chip rigidity can be obtained, it can be used for heavy cutting or high-speed cutting without causing damage to the cutting edge. Also, each side 2
5 and 35 are formed in a convex curved shape, thereby forming the outer circumferential cutting edge 22 and the bottom edge 32 in a convex curved shape, and furthermore, the outer circumferential tip 16 has a corner portion sandwiched between the cutting edge 22 and the cutting edge 32. Since the nose blade 26 is formed on the inner circumferential tip 17 at the corner portion sandwiched between the cutting blades 32 and 33, positive An axial rake angle having a rate of change is formed, which reduces cutting resistance and improves sharpness, thereby preventing chatter and vibration of the entire end mill body 10, thereby providing an excellent finished surface. Accuracy can be obtained. Moreover, the convex curved side surface 2 which is the rake surface
5 and 35, it is possible to divide the chips generated during cutting into appropriate lengths and to smoothly discharge them outward along the respective convex curved surfaces, making it possible to Excellent chip evacuation performance. In addition, since the small cutting edge 27 of the outer circumferential tip 16 is continuous with the cutting edge 32 of the inner circumferential tip 17 in the rotation locus, it has excellent drilling performance, and the machining surface parallel to the end mill axis direction and the machining surface on the end mill tip side It is possible to obtain good angularity and excellent finishing accuracy at the corners.

[Effects of the invention] As explained above, the end mill of this invention has the following advantages:
Each has a plate shape, with a cutting edge formed on the ridge of the upper surface, a nose edge formed at the corner sandwiched by the cutting edge, and a side surface extending from the cutting edge to the lower surface which is the seating surface. However, the inner circumferential tip and the outer circumferential tip are formed by convex curved surfaces in which the width between the side surfaces at the center of the cutting edge is larger than each width at both ends of the cutting edge. The bottom surface of the tip is brought into contact with the tip surface of the end mill body, and its cutting edge is used as the bottom edge, so that its side surface is used as a rake surface.On the other hand, the outer circumferential tip has its top surface facing the outer circumferential side of the end mill body, and its cutting edge By making the outer circumferential cutting edge, its side surface becomes a rake surface, and the small cutting edge formed on the ridge line of the side surface that intersects with the tip side of the outer circumferential cutting edge is aligned with the bottom edge of the inner circumferential chip in the rotation locus. They are connected to each other and attached to the end mill body.

Therefore, according to this end mill, the load generated by cutting is received between both sides of the chip, which has excellent rigidity, so that high tool rigidity can be obtained. As a result, even when used for heavy cutting, there is no risk of damage to the cutting edge. In addition, the side surface, which serves as the rake face, is formed with a convex curve to give the cutting edge and bottom edge a convex curve shape, and an axial rake angle with a positive rate of change is formed with the apex of the nose edge as the base point, making it easier to cut. It is possible to reduce the resistance, improve sharpness, and facilitate chip discharge, thereby achieving both excellent cutting performance and chip discharge performance.

[Brief explanation of the drawing]

1 to 11 show an embodiment of the end mill of this invention, in which FIG. 1 is a front view, FIG. 2 is a bottom view, FIG. 3 is a - line view of FIG. 2, and FIG. The figure is a front view showing the tip attached to the end mill as the outer circumferential tip, and Figure 5 is the same as in Figure 4.
A line sectional view, FIG. 6 is a - line view of FIG. 4,
FIG. 7 is a front view showing a tip installed as an inner peripheral tip in the end mill, FIG. 8 is a cross-sectional view taken along the - line in FIG. 7, FIG. 9 is a view taken along the - line in FIG. 7, and FIG. The figure is a side cross-sectional view showing the rotation locus of the inner circumferential tip and the outer circumferential tip, FIG. 11 is a view taken along the - line in FIG. 2, FIG. 12 and FIG. is the bottom view,
FIG. 13 is a front view. 10...End mill body, 12...Outer peripheral surface, 1
3,15...Tip seat, 14...Tip surface, 16...
...(Outer circumference) Chip, 17...(Inner circumference) Chip, 2
0,30...Top surface, 21,31...Bottom surface, 22,
23, 32, 33...cutting blade, 25, 35...side surface, 26, 36...nose blade, 27...small cutting blade.

Claims (1)

[Scope of utility model registration request] The end mill body includes an end mill body that rotates around an axis, an inner tip attached to the tip surface of the end mill body, and an outer tip attached to the outer periphery of the tip of the end mill body. Each of the outer chips has a parallelogram plate shape, and a cutting edge is formed on the ridge of the upper surface, and a nose edge is formed at the corner sandwiched between the cutting edges, and from the cutting edge to the seating surface. The side surface leading to the lower surface of the end mill body is formed by a convex curved surface that is larger than the width between the side surfaces at the center of the cutting blade, and the inner peripheral tip has its lower surface facing the tip surface of the end mill body. By bringing the cutting edge into contact with the bottom edge, the side surface becomes a rake face,
On the other hand, the outer peripheral tip has its upper surface facing the outer peripheral side of the end mill main body so that the cutting edge serves as an outer peripheral cutting edge, so that the side surface thereof becomes a rake face, and the cutting edge serves as an outer peripheral cutting edge. A small cutting edge formed on the ridge line of the side surface that intersects with the tip side of the end mill is connected to the cutting edge serving as the bottom edge of the inner circumferential tip in a rotation locus, and is attached to the end mill body. An end mill with a bottom blade.