JP7226685B2 - Cutting tools - Google Patents

Description

The present invention relates to cutting tools. More particularly, the present invention relates to cutting tools for skiving.

For example, Patent Document 1 (Japanese National Publication of International Patent Application No. 2003-516868) describes a cutting tool for skiving. The cutting tool described in Patent Document 1 has a cutting edge extending linearly.

In the skiving process using the cutting tool described in Patent Document 1, the cutting tool described in Patent Document 1 has its cutting edge arranged with an inclination with respect to the central axis of the work material, and its cutting edge is fed across the central axis of the workpiece. As a result, the work material is cut while the cutting point moves sequentially on the cutting edge of the cutting tool described in Patent Document 1.

Japanese Patent Publication No. 2003-516868

However, in the cutting tool described in Patent Document 1, the cutting resistance is fluctuates. As a result, the cutting tool described in Patent Document 1 has room for improvement in resistance to sudden chipping of the cutting edge.

The present invention has been made in view of the problems of the prior art as described above. More specifically, the present invention provides a cutting tool capable of suppressing sudden chipping of the cutting edge.

A cutting tool according to one aspect of the present invention includes a rake face, a flank that continues to the rake face, and a cutting edge that is formed on a ridge line between the rake face and the flank face. The cutting tool has a polygonal shape in plan view. The cutting edges are formed along the sides of the polygonal shape. The cutting edge includes a first portion extending linearly in plan view, and a second portion positioned at one end of the first portion and extending so as to form an obtuse angle with respect to the first portion in plan view. have.

According to the cutting tool according to one aspect of the present invention, it is possible to suppress sudden chipping of the cutting edge.

1 is a perspective view of a cutting tool 10; FIG. 3 is a plan view of the cutting tool 10 in the vicinity of the cutting edge 3. FIG. 3 is an enlarged plan view of a portion where the first portion 31 and the second portion 32 of the cutting tool 10 are connected to each other; FIG. 3 is an enlarged plan view of a portion where the first portion 31 and the third portion 33 of the cutting tool 10 are connected to each other; FIG. FIG. 2 is a schematic diagram of skiving using the cutting tool 10. FIG. 3 is a plan view of the cutting tool 20 in the vicinity of the cutting edge 3. FIG. 3 is a plan view of the cutting tool 30 in the vicinity of the cutting edge 3. FIG. 3 is a plan view of the cutting tool 40 in the vicinity of the cutting edge 3. FIG.

[Description of the embodiment of the present invention]
First, embodiments of the present invention will be listed and described.

(1) A cutting tool according to an embodiment of the present invention includes a rake face, a flank that continues to the rake face, and a cutting edge that is formed on the ridge line between the rake face and the flank face. The cutting tool has a polygonal shape in plan view. The cutting edges are formed along the sides of the polygonal shape. The cutting edge includes a first portion extending linearly in plan view, and a second portion positioned at one end of the first portion and extending so as to form an obtuse angle with respect to the first portion in plan view. have.

In the cutting tool of (1) above, since the second portion is continuous with one end of the first portion, it becomes a portion where the cutting edge bites into the work material or a portion where the cutting edge leaves the work material. In addition, in the cutting tool of (1) above, the second portion extends so as to form an obtuse angle with respect to the first portion, so that the second portion recedes relative to the work material more than the first portion. in position. That is, the amount of cut in the second portion is relatively smaller than the amount of cut in the first portion. As a result, according to the cutting tool of (1) above, the fluctuation of the cutting resistance generated in the cutting edge when biting into the work material or when coming out of the work material is alleviated, and sudden chipping of the cutting edge is suppressed. It becomes possible to

(2) In the cutting tool of (1) above, the second portion may extend linearly in plan view.

(3) In the cutting tool of (2) above, the angle formed by the first portion and the second portion may be greater than 179°.

According to the cutting tool of (3) above, since the cutting resistance between the cutting edge and the work material changes gently from the first part to the second part, when biting into the work material or coming out of the work material Fluctuations in the cutting resistance that occurs in the cutting edge at this time are further alleviated, making it possible to further suppress sudden breakage of the cutting edge.

(4) In the cutting tools of (1) to (3) above, the cutting edge is located at the other end of the first portion and extends to form an obtuse angle with respect to the first portion in plan view. It may further have a portion.

According to the cutting tool of (4) above, the second portion is connected to one end of the first portion, and the third portion is connected to the other end of the first portion. Fluctuations in the cutting resistance generated in the cutting edge when it is removed from the work material are reduced, and it is possible to further suppress sudden breakage of the cutting edge.

(5) In the cutting tool of (4) above, the third portion may extend linearly in plan view.

(6) In the cutting tool of (5) above, the angle formed by the first portion and the third portion may be greater than 179°.

According to the cutting tool of (6) above, the cutting resistance between the cutting edge and the work material changes gently from the first part to the second part, and changes gently from the first part to the third part. Therefore, fluctuations in the cutting resistance generated in the cutting edge when it bites into the work material and when it comes out of the work material are further mitigated, and it is possible to further suppress sudden chipping of the cutting edge.

(7) In the cutting tools of (4) to (6) above, the value obtained by dividing the width of the first portion in the extending direction of the first portion by the width of the cutting edge in the extending direction of the first portion is 0. It may be 7 or more and 0.99 or less.

[Details of the embodiment of the present invention]
Next, details of embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts are denoted by the same reference numerals, and redundant description will not be repeated.

(Structure of cutting tool according to embodiment)
A configuration of a cutting tool (hereinafter referred to as "cutting tool 10") according to the embodiment will be described.

The cutting tool 10 is a cutting tool for skiving. FIG. 1 is a perspective view of a cutting tool 10. FIG. As shown in FIG. 1 , the cutting tool 10 has a rake face 1 , a flank face 2 and a cutting edge 3 . The flank face 2 is continuous with the rake face 1 . A cutting edge 3 is formed on the ridge between the rake face 1 and the flank face 2 .

The cutting tool 10 has a polygonal shape in plan view. Here, “plan view” refers to a case where the cutting tool 10 is viewed from a direction perpendicular to the rake face 1 . In the example shown in FIG. 1, the cutting tool 10 has a triangular shape in plan view, but the cutting tool 10 may have a polygonal shape other than the triangular shape (eg, quadrangle, trapezoid, etc.). good. In addition, this "polygonal shape" does not have to be a perfect polygonal shape. Its corners are rounded, etc.). The cutting edge 3 is formed along the sides of this polygonal shape. In addition, the cutting edge 3 should just be formed in at least 1 side of the sides which comprise this polygonal shape.

A cutting tool 10 has a base material 11 , a sintered body 12 and a bonding layer 13 . The base material 11 is made of cemented carbide, for example. The substrate 11 has a top surface 11a, a back surface 11b and side surfaces 11c. The top surface 11a constitutes a part of the rake face 1. As shown in FIG. The back surface 11b is the surface opposite to the top surface 11a. The side surface 11c continues to the top surface 11a and the rear surface 11b. The side surface 11c forms part of the flank surface 2. As shown in FIG.

The top surface 11a has a seat portion 11d. The distance between the top surface 11a and the back surface 11b of the seat surface portion 11d is smaller than the distance between the top surface 11a and the back surface 11b other than the seat surface portion 11d. That is, a step is formed in the seat surface portion 11d of the top surface 11a.

The sintered body 12 is formed of a sintered body of a hard material. This hard material is, for example, a sintered body of cubic boron nitride (CBN). The sintered body 12 is arranged on the bearing surface portion 11d. The sintered body 12 is bonded to the base material 11 by a bonding layer 13 arranged between the sintered body 12 and the seat portion 11d.

In the above, the case where the cutting tool 10 is composed of the base material 11, the sintered body 12, and the bonding layer 13 is shown as an example, but the cutting tool 10 is composed only of the base material 11 in a similar shape. may be

FIG. 2 is a plan view of the cutting tool 10 in the vicinity of the cutting edge 3. FIG. As shown in FIG. 2 , the cutting edge 3 has a first portion 31 , a second portion 32 and a third portion 33 .

The first portion 31 extends linearly in plan view (hereinafter, the extending direction of the first portion 31 is referred to as “extending direction DR”). The first portion 31 has a first end 31a and a second end 31b in the extending direction DR. The second end 31b is the end opposite to the first end 31a.

The second portion 32 continues to the first portion 31 at the first end 31a. The second portion 32 extends linearly in plan view. In plan view, the first portion 31 and the second portion 32 form an angle θ1. The angle θ1 is an obtuse angle (greater than 90° and less than 180°). The angle θ1 is preferably greater than 179° and less than 180°.

FIG. 3 is an enlarged plan view of the portion where the first portion 31 and the second portion 32 of the cutting tool 10 are connected to each other. As shown in FIG. 3, the corner formed by the first portion 31 and the second portion 32 may be rounded. When the corner formed by the first portion 31 and the second portion 32 is rounded, the angle θ1 is calculated as the angle between the extension line L1 of the first portion 31 and the extension line L2 of the second portion 32. .

The third portion 33 continues to the first portion 31 at the second end 31b. The third portion 33 extends linearly in plan view. In plan view, the first portion 31 and the third portion 33 form an angle θ2. The angle θ2 is an obtuse angle. The angle θ2 is preferably greater than 179° and less than 180°.

FIG. 4 is an enlarged plan view of the portion where the first portion 31 and the third portion 33 of the cutting tool 10 are connected to each other. As shown in FIG. 4, the corner formed by the first portion 31 and the third portion 33 may be rounded. When the corner formed by the first portion 31 and the third portion 33 is rounded, the angle θ2 is calculated as the angle between the extension line L1 of the first portion 31 and the extension line L3 of the third portion 33. .

As shown in FIG. 2, the first portion 31 has a width W1 in the extending direction DR. The cutting edge 3 has a width W2 in the extending direction DR. The value obtained by dividing the width W1 by the width W2 is preferably 0.7 or more and 0.99 or less.

In the above description, the cutting edge 3 has both the second portion 32 and the third portion 33, but the cutting edge 3 includes at least one of the second portion 32 and the third portion 33. It's fine if you have it.

(Skiving using the cutting tool according to the embodiment)
Skiving using the cutting tool (cutting tool 10) according to the embodiment will be described.

FIG. 5 is a schematic diagram of skiving using the cutting tool 10. FIG. As shown in FIG. 5, the work W rotates around the central axis A. As shown in FIG. The cutting tool 10 is arranged so that the cutting edge 3 is inclined with respect to the central axis A direction. The cutting tool 10 is fed in a direction in which the cutting edge 3 crosses the central axis A. More specifically, the cutting tool 10 is fed along a direction orthogonal to the central axis A or a direction inclined with respect to the central axis A.

As a result, at the start of cutting, the cutting edge 3 contacts the outer peripheral surface of the work W on the side of the second portion 32 (the contact point between the cutting edge 3 and the work W is called a cutting point), but the progress of cutting As a result, the cutting point sequentially contacts the first portion 31 and the third portion 33 . Thus, in skiving, since the cutting point moves on the cutting edge 3 sequentially, wear is distributed over the entire cutting edge 3 . When the cutting tool 10 is arranged as shown in FIG. 5, the cutting point moves from the second portion 32 side to the third portion 33 side (at the second portion 32 side, it bites into the workpiece W, However, if the arrangement of the cutting tool 10 is changed, the cutting point moves from the third portion 33 side to the second portion 32 side (on the third portion 33 side, It bites into the work material W and comes out of the work material W on the second portion 32 side.

(Effect of cutting tool according to embodiment)
Effects of the cutting tool (cutting tool 10) according to the embodiment will be described.

In the cutting tool 10, when the cutting edge 3 bites into the work material W (at the time of biting) and when the cutting edge 3 comes out of the work material W (at the time of coming off), the cutting edge 3 has a relatively large cutting force. A variation in resistance occurs. This variation in cutting resistance causes sudden chipping of the cutting edge 3 .

Since the second portion 32 and the third portion 33 extend linearly so as to form an obtuse angle with respect to the first portion 31 , they recede relative to the work material W more than the first portion 31 . position. That is, the amount of cut in the second portion 32 and the amount of cut in the third portion 33 is relatively smaller than the amount of cut in the first portion 31 . As described above, the second portion 32 and the third portion 33 are portions of the cutting edge 3 that come into contact with the work material W during biting and removal. Due to the relatively small size, fluctuations in the cutting resistance applied to the cutting edge 3 during biting and removal are mitigated. Therefore, according to the cutting tool 10 , it is possible to suppress sudden breakage of the cutting edge 3 .

If the cutting edge 3 has either the second portion 32 or the third portion 33, the fluctuation of the cutting resistance applied to the cutting edge 3 at the time of biting or breaking can be reduced. Therefore, if the cutting edge 3 has either the second portion 32 or the third portion 33 , the cutting tool 10 can suppress sudden chipping of the cutting edge 3 .

When the angles θ1 and θ2 are more than 179° and less than 180° in the cutting tool 10, the cutting resistance between the cutting edge 3 and the work W is from the first portion 31 to the second portion 32. Since it changes gently and changes gently from the first part 31 to the third part 33, the fluctuation of the cutting resistance generated in the cutting edge 3 at the time of biting and pulling out is further alleviated, and sudden chipping of the cutting edge can be further suppressed.

(Modification)
Below, the cutting tool according to the first modification (hereinafter referred to as "cutting tool 20"), the cutting tool according to the second modification (hereinafter referred to as "cutting tool 30") and the cutting tool according to the third modification (hereinafter " cutting tool 40") will be described.

FIG. 6 is a plan view of the cutting tool 20 in the vicinity of the cutting edge 3. FIG. As shown in FIG. 6, the configuration of the cutting tool 20 differs from that of the cutting tool 10 in that the second portion 32 and the third portion 33 are each configured by connecting a plurality of straight lines. . Note that when the second portion 32 (third portion 33) is configured by connecting a plurality of straight lines, "the second portion 32 (third portion 33) is at an obtuse angle to the first portion 31 in plan view." "extends to form" means that the angle formed by each straight line forming the second portion 32 (the third portion 33) and the first portion 31 is an obtuse angle.

FIG. 7 is a plan view of the cutting tool 30 in the vicinity of the cutting edge 3. FIG. FIG. 8 is a plan view of the cutting tool 40 in the vicinity of the cutting edge 3. FIG. As shown in FIGS. 7 and 8, the configuration of the cutting tool 20 and the cutting tool 30 is similar to that of the cutting tool 10 in that the second portion 32 and the third portion 33 extend curvedly in plan view. configuration is different. Note that when the second portion 32 (third portion 33) extends in a curved line, "the second portion 32 (third portion 33) forms an obtuse angle with respect to the first portion 31 in plan view." The term "extending" means that the first portion 31 forms an obtuse angle with the tangent line of the curved line forming the second portion 32 (the third portion 33).

As shown in FIG. 7, in the cutting tool 30, the second portion 32 and the third portion 33 are each formed of a single curve in plan view. As shown in FIG. 8, in the cutting tool 40, the second portion 32 and the third portion 33 are each configured by connecting a plurality of curved lines in plan view.

According to the cutting tool 20, the cutting tool 30, and the cutting tool 40, the amount of cut in the second portion 32 and the third portion 33 is relatively small, so that the cutting resistance applied to the cutting edge 3 at the time of biting and pulling out is changed. is alleviated, it is possible to suppress sudden chipping of the cutting edge 3.

The embodiments disclosed this time are illustrative in all respects and should be considered not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above-described embodiments, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

1 rake face 2 flank face 3 cutting edge 10, 20, 30, 40 cutting tool 11 base material 11a top face 11b back face 11c side face 11d bearing surface portion 12 sintered body 13 bonding layer 31 first portion 31a first end 31b second end 32 Second portion 33 Third portion A Central axis DR Extension directions L1, L2, L3 Extension line W Work material W1, W2 Width

Claims (2)

A cutting tool for skiving ,
rake face;
a flank surface contiguous with the rake surface;
A cutting edge formed on the ridge between the rake face and the flank face,
The cutting tool has a polygonal shape in plan view,
The cutting edge is formed along a side of the polygonal shape,
The cutting edge is located at one end of the first portion that extends linearly in plan view and the first portion, and extends to form an obtuse angle with respect to the first portion in plan view. 2 parts and
The second portion extends linearly in plan view,
A portion where the first portion and the second portion are connected to each other is rounded in plan view,
an angle formed by the first portion and the second portion is greater than 179°;
The cutting edge is located at the other end of the first portion and is the first portion in plan view.
further comprising a third portion extending at an obtuse angle to the minute;
The third portion extends linearly in plan view,
A cutting tool , wherein the angle formed by the first portion and the third portion is greater than 179° . Claim 1 , wherein the value obtained by dividing the width of the first portion in the extending direction of the first portion by the width of the cutting edge in the extending direction of the first portion is 0.7 or more and 0.99 or less. The cutting tool described in .

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