JP2010037751A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool attaining suitable cutting. <P>SOLUTION: A cutting tip 10 of the cutting tool 100 has a first flank 21, a second flank 22 and a third flank 23 which are continuous backward in a cutting direction from a cutting edge 3 formed at a cross ridgeline of a rake face 1 and a flank 2, and is formed to increase a clearance angle of the flank as it goes away from the cutting edge 3. Consequently, even when the cutting edge 3 is worn out, the increase of a contact area between the cutting finished surface of a cut object and the cutting tip 10 can be suppressed to attain suitable cutting. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cutting tool for cutting ground.

Conventionally, an earth auger is known as a device for excavating the ground to form an excavation hole. The auger head which is the lower end of the earth auger is provided with an auger bit which is a cutting tool for cutting the ground or rock.
The auger bit is composed of a steel bit main body and a cemented carbide cutting blade tip joined to the bit main body by brazing or the like (for example, see Patent Document 1).
JP-A-4-176987

  However, in the case of the above-mentioned Patent Document 1, the flank of the cutting edge tip in the auger bit is composed of one element of the clearance angle β, and therefore the wear of the cutting edge tip proceeds as the auger bit cuts hard rock. The contact area between the flank of the cutting edge tip and the rock is likely to increase, and the excavation resistance increases as the contact area increases, resulting in a problem that the excavation efficiency decreases.

  An object of the present invention is to provide a cutting tool that enables suitable cutting.

In order to solve the above problems, the invention described in claim 1
A cutting tool comprising: a shaft portion connected to a predetermined excavation device; and a cutting portion provided on the front end side of the shaft portion and in contact with the ground,
The cutting portion is provided with a cutting tip having a rake face, a flank face, and a cutting edge that is formed at an intersecting ridge line of the rake face and the flank face and substantially perpendicular to the cutting direction,
The flank has a first flank that contacts the cutting edge and a second flank that contacts the first flank and is positioned behind the first flank, and the flank angle of the first flank Further, the clearance angle of the second flank is larger.

The invention according to claim 2 is the cutting tool according to claim 1,
The flank is characterized by being formed with at least one recess that is recessed in a direction that increases the flank angle and that extends away from the cutting edge.

The invention according to claim 3
A cutting tool comprising: a shaft portion connected to a predetermined excavation device; and a cutting portion provided on the front end side of the shaft portion and in contact with the ground,
The cutting portion is provided with a cutting tip having a rake face, a flank face, and a cutting edge that is formed at an intersecting ridge line of the rake face and the flank face and substantially perpendicular to the cutting direction,
The flank is characterized by being formed with at least one recess that is recessed in a direction that increases the flank angle of the flank and extends away from the cutting edge.

The invention according to claim 4 is the cutting tool according to any one of claims 1 to 3,
The angle at which at least one of the side surfaces of the cutting tip intersects with the extending direction of the cutting blade is less than 90 degrees.

The invention according to claim 5 is the cutting tool according to claim 4,
The side surface has a first side surface close to the cutting edge and a second side surface positioned rearward of the first side surface, and the cutting edge is formed from an angle formed by the extending direction of the cutting edge and the first side surface. The angle between the extending direction of the blade and the second side surface is smaller.

The invention according to claim 6 is the cutting tool according to claim 4 or 5,
The side surface is formed with at least one concave portion that is recessed in a direction in which an angle formed with the extending direction of the cutting blade is reduced and extends in a direction away from the cutting blade.

The invention according to claim 7 is the cutting tool according to any one of claims 1 to 6,
The cutting tip is fixed to the attachment groove on the tip side of the cutting part, and the length of the cutting tip from the opening end of the attachment groove to the cutting edge with respect to the width of the side surface along the cutting direction of the cutting tip. The ratio is 50% or more and less than 125%.

According to the present invention, the cutting tip of the cutting tool includes a plurality of flank surfaces that are continuous from the cutting edge formed at the crossing ridge line of the rake surface and the flank surface to the rear in the cutting direction, and concave portions formed on the flank surface. Since the cutting tip has at least two relief elements, even if the cutting edge as the cutting edge is worn, the increase in the contact area between the cutting finish surface of the cutting object and the cutting tip is suppressed. Can do. And it becomes possible to reduce cutting resistance by suppressing the increase in the contact area of a cutting tip and a cutting finish surface, and can improve cutting efficiency and extend the lifetime of a cutting tool.
That is, this cutting tool can be used for cutting work longer than conventional cutting tools because it does not deteriorate sharply even when the cutting edge of the cutting tip is worn, and it can sufficiently withstand its use. Makes it possible to cut smoothly.

Hereinafter, a cutting tool according to an embodiment of the present invention will be described with reference to the drawings.
In the present embodiment, a cutting tool as a cutting claw (orugite) supported by a holder such as an auger head will be described as an example.

(Embodiment 1)
As shown in FIGS. 1 and 2, for example, the cutting tool 100 is provided with a shaft portion 12 connected to a holder 20 of an auger head as an excavating device, and is provided on the front end side of the shaft portion 12 to be in contact with the ground. The cutting part 11 etc. are provided.
The cutting tool 100 has a shape whose width when viewed from the side (see FIG. 1) is wider than the width when viewed from the front (see FIG. 2).

  The shaft portion 12 includes an engaging portion 121 located at the rear end portion of the shaft portion, a shaft-side tapered surface portion 122 extending from the engaging portion 121 to the front end of the shaft portion, and a raised portion formed on the shaft-side tapered surface portion 122. 123.

The engaging part 121 includes an annular groove 121a provided on the rear end side of the shaft part 12, and a retaining member 121b fitted into the annular groove 121a.
The annular groove 121a is a groove portion formed so as to make a round around the rear end of the shaft portion in a direction substantially orthogonal to the axial direction (longitudinal direction) of the shaft portion 12.
The retaining member 121b is, for example, an O-ring or an expansion / contraction ring, and is in close contact with the inner surface of the support hole 21 of the holder 20.

  The shaft-side taper surface portion 122 is a portion having a substantially truncated cone shape in which a taper tapering toward the rear end side of the shaft portion 12 is provided on the outer surface of the shaft portion 12. The shape is easy to insert into the support hole 21.

The raised portion 123 is a direction in which the shaft portion 12 is inserted into the support hole 21 of the holder 20, is long in the axial direction (longitudinal direction) of the shaft portion 12, and is formed on the inner surface of the support hole 21 into which the shaft portion 12 is inserted. It has a shape that protrudes upward.
By inserting the shaft portion 12 into the support hole 21 so that the raised portion 123 is aligned with the positioning groove portion 213 on the inner wall of the support hole 21, the cutting tool 100 can be attached to the holder 20 in a predetermined direction. It has become.

  The cutting part 11 includes a cutting part main body 112 in which a mounting groove 111 having a substantially U shape in a side view is formed on the tip side, and a cutting tip 10 embedded and fixed in the mounting groove 111. .

  The cutting part main body 112 is made of a material such as carbon steel, alloy steel, or high speed steel, for example. The cutting part body 112 is formed integrally with the shaft part 12.

  The cutting tip 10 is a blade portion made of a hard material such as cemented carbide, cermet, or ceramics, and is firmly fixed to the mounting groove 111 of the cutting portion 11 by a method such as brazing, welding, or pressure welding. . The cutting tip 10 is fixed so that the tip side protrudes from the opening end 111a of the mounting groove 111 by a predetermined amount (for example, length E).

As shown in FIG. 1, the cutting tip 10 includes a rake face 1, a flank face 2, and a cutting edge 3 that is formed at the intersection ridge line of the rake face 1 and the flank face 2 and is substantially orthogonal to the cutting direction. Have.
The rake face 1 is located on the front face in the cutting direction from the cutting edge 3, and the flank face 2 is located on the rear face in the cutting direction from the cutting edge 3.
The cutting blade 3 hits a cutting object such as the ground or rock, and forms a cutting edge for cutting the cutting object. The cutting edge 3 is preferably orthogonal to the cutting direction, and the allowable angle is in the range of ± 10 °.
The rake face 1 is a face that removes shavings such as earth and sand cut by the cutting blade 3 so as to scoop up from the cut finish surface of the object to be cut.
In order to minimize the contact between the cutting finish surface of the object to be cut and the cutting tip 10, the flank 2 is angled in a direction away from the cutting edge 3 and the cutting finish surface (flank angle). It is the side where it was made.

In particular, as shown in FIG. 1, the flank 2 includes a first flank 21 in contact with the cutting edge 3, and a second flank 22 in contact with the first flank 21 and positioned behind the first flank 21. And a third flank 23 which is in contact with the second flank 22 and located behind the second flank 22.
The first flank 21 forms a clearance angle α1 with respect to the finished surface, the second flank 22 forms a clearance angle α2 with respect to the finished surface, and the third flank 23 escapes with respect to the finished surface. An angle α3 is formed.
The clearance angle α2 of the second clearance surface 22 is larger than the clearance angle α1 of the first clearance surface 21, and the clearance angle α3 of the third clearance surface 23 is larger than the clearance angle α2 of the second clearance surface 22. Thus, each flank is formed.

Thus, the cutting tip 10 of the cutting tool 100 has the first flank 21, the second flank 22, and the third flank 23 continuous from the cutting edge 3 to the rear in the cutting direction. Since the clearance angle of the flank increases as the distance from the surface increases, an increase in the contact area between the cutting finish surface of the object to be cut and the cutting tip 10 is suppressed even when the cutting edge 3 as the cutting edge is worn. be able to. Then, by suppressing an increase in the contact area between the cutting tip 10 and the finished cutting surface, it becomes possible to reduce cutting resistance (excavation resistance), improve cutting efficiency (excavation efficiency), and the life of the cutting tool 100. Can be extended.
That is, the cutting tool 100 does not deteriorate sharply even when the cutting edge of the cutting tip 10 is worn, and can sufficiently withstand the use of the cutting tool 100 (for example, the flank has a clearance angle β of 1). It can be used for a cutting operation longer than a cutting edge chip made of an element, and enables suitable cutting.

  Moreover, as shown in FIG. 1, it is the length of the longitudinal direction when the cutting tip 10 fixed to the attachment groove 111 of the cutting part 11 is viewed from the side, and the tip of the cutting edge (cutting edge 3) of the cutting tip 10 The length from the mounting groove 111 to the deepest of the mounting groove 111 is L, the width of the mounting groove 111 and the width (thickness) of the side surface of the cutting tip 10 is W, and the cutting edge 3 When the length of the cutting tip 10 to the tip is E, the cutting tip from the opening end 111a of the mounting groove 111 to the tip of the cutting blade 3 with respect to the width (W) of the side surface parallel to the cutting direction of the cutting tip 10 The size and shape of the cutting tip 10 in the cutting tool 100 are defined so that the ratio of length 10 (E) ((E / W) × 100) is 50% or more and less than 125%.

  This prepares the cutting tool 100 provided with the cutting tip 10 of various width (W) and length (E), as shown in FIG. 3 with respect to the cutting tip 10 fixed to each cutting tool 100, A test (stress analysis test) that measures the load applied to each cutting tip 10 when a load of 10 [t] is applied to the direction along the cutting direction and the excavation propulsion direction that is the longitudinal direction of the cutting tip 10. ), It was determined that the load of the cutting tip 10 is small, ◯, the load of the cutting tip 10 is slightly large, △, the load of the cutting tip 10 is determined to be ×, as shown in FIG. When the ratio ((E / W) × 100) of the length (E) of the cutting tip 10 from the open end 111a to the tip of the cutting blade 3 with respect to the width (W) of the cutting tip 10 is less than 50%, the cutting tip 10 is relatively large This is because, when the ratio ((E / W) × 100) becomes 125% or more, it has been found that the load applied to the cutting tip 10 becomes relatively large.

  Therefore, by defining the size and shape of the cutting tip 10 in the cutting tool 100 so that the ratio ((E / W) × 100) is 50% or more and less than 125%, The load applied to the cutting tip 10 can be reduced, and suitable cutting can be performed.

  As described above, the cutting tip 10 of the cutting tool 100 has the first flank 21, the second flank 22, and the third flank 23 continuous from the cutting edge 3 to the rear in the cutting direction. The clearance angle of the flank increases as the distance from 3 increases, and the length (E) of the cutting tip 10 from the opening end 111a to the tip of the cutting edge 3 with respect to the width (W) of the cutting tip 10 is Since it is formed so as to have a preferred ratio of 50% or more and less than 125% ((E / W) × 100), this cutting tool 100 enables suitable cutting.

(Embodiment 2)
Next, Embodiment 2 of the cutting tool according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1, and only a different part is demonstrated.

  As shown in FIG. 5, the cutting tool 200 includes a shaft portion 12 and a cutting portion 11 provided on the front end side of the shaft portion 12, and the cutting tip 10 a is fixed to the mounting groove 111 of the cutting portion 11. Has been.

The cutting tip 10 a has a rake face 1, a flank face 24, and a cutting edge 3 formed at a cross ridge line of the rake face 1 and the flank face 24. The flank 24 has a flank angle α4 with respect to the cut finish surface.
The relief surface 24 is formed with four concave grooves 44 that are recessed in the direction in which the relief angle α4 of the relief surface 24 increases and extend away from the cutting edge 3. The concave groove 44 is a concave portion having a depth of the escape amount u1 from the flank 24.

  As described above, the cutting tip 10a of the cutting tool 200 has the flank 24 located rearward in the cutting direction from the cutting edge 3, and the flank 24 has a recessed groove 44 that is recessed to a depth of the evacuation amount u1. Since it is formed, even when the cutting edge 3 that is the cutting edge is worn, an increase in the contact area between the cutting finish surface of the object to be cut and the cutting tip 10a can be suppressed by the portion corresponding to the concave groove 44. . Further, by suppressing an increase in the contact area between the cutting tip 10a and the finished cutting surface, it becomes possible to reduce cutting resistance (excavation resistance), improve cutting efficiency (excavation efficiency), and improve the life of the cutting tool 200. Can be extended.

  In the cutting tool 200 according to this embodiment, in the region where the concave groove 44 of the flank 24 is formed, the flank 24 is formed so as to form a rib protruding from the bottom surface of the concave groove 44. By forming the rib-shaped flank 24, it is possible to suppress a decrease in strength of the cutting tip 10a due to the formation of the concave groove 44.

  Even in the case of the cutting tool 200 including the cutting tip 10a having the flank 24 in which the concave groove 44 is formed, the cutting efficiency is not rapidly deteriorated when the cutting edge of the cutting tip 10a is worn. Is possible.

(Embodiment 3)
Next, a third embodiment of the cutting tool according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1, 2, and only a different part is demonstrated.

  As shown in FIG. 6, the cutting tool 300 includes a shaft portion 12 and a cutting portion 11 provided on the front end side of the shaft portion 12, and the cutting tip 10 b is fixed to the mounting groove 111 of the cutting portion 11. Has been.

The cutting tip 10 b has a rake face 1, a flank face 25, and a cutting edge 3 formed at the ridge line of the rake face 1 and the flank face 25. The flank 25 forms a flank angle α5 with respect to the cut finish surface.
Further, the flank 25 is formed with three grooves 45 that are recessed in a direction in which the flank angle 5 of the flank 25 increases and extend in a direction away from the cutting edge 3. The concave groove 45 is a concave portion having a depth of the escape amount u2 from the flank 25.
In particular, the concave groove 45 is a hollow having a substantially triangular shape that widens as the distance from the cutting edge 3 increases.

In this way, the cutting tip 10b of the cutting tool 300 has the flank 25 located behind the cutting edge 3 in the cutting direction, and the flank 25 has a recessed groove 45 that is recessed to a depth of the evacuation amount u2. Since it is formed, even when the cutting edge 3 as the cutting edge is worn, an increase in the contact area between the cutting finish surface of the object to be cut and the cutting tip 10b can be suppressed by the portion corresponding to the concave groove 45. .
In particular, since the concave groove 45 has a substantially triangular shape that is widened as the distance from the cutting edge 3 increases, even when the cutting edge 3 wears, the relief element corresponding to the concave groove 45 is large. It is possible to further suppress an increase in contact area with the cutting tip 10b. Further, by suppressing an increase in the contact area between the cutting tip 10b and the finished cutting surface, it becomes possible to reduce the cutting resistance (excavation resistance), improve the cutting efficiency (excavation efficiency), and the life of the cutting tool 300. Can be extended.

  In the cutting tool 300 according to this embodiment, in the region where the concave groove 45 of the flank 25 is formed, the flank 25 is formed so as to form a rib protruding from the bottom surface of the concave groove 45. By forming the rib-shaped flank 25, it is possible to suppress the strength reduction of the cutting tip 10b due to the formation of the concave groove 45.

  Even if it is the cutting tool 300 provided with the cutting tip 10b which has the flank 25 in which such a ditch | groove 45 was formed, when the cutting edge of the cutting tip 10b is worn, cutting efficiency does not deteriorate rapidly, Therefore suitable cutting Is possible.

(Embodiment 4)
Next, Embodiment 4 of the cutting tool according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1-3, and only a different part is demonstrated.

  As shown in FIG. 7, the cutting tool 400 includes a shaft portion 12 and a cutting portion 11 provided on the front end side of the shaft portion 12, and the cutting tip 10 c is fixed to the mounting groove 111 of the cutting portion 11. Has been.

The cutting tip 10 c has a rake face 1, a flank face 2, and a cutting edge 3 formed on a cross ridge line between the rake face 1 and the flank face 2.
In particular, as shown in FIG. 7, the flank 2 includes a first flank 26 that contacts the cutting edge 3, and a second flank 27 that is in contact with the first flank 26 and is located behind the first flank 26. have.
The first flank 26 forms a clearance angle α6 with respect to the cut finish surface, and the second flank 27 forms a clearance angle α7 with respect to the cut finish surface.
Each flank is formed such that the flank angle α7 of the second flank 27 is larger than the flank angle α6 of the first flank 26.

Further, the cutting tip 10 c has a side surface 5 and a side surface 6 on both end sides of the cutting edge 3 corresponding to the intersecting ridge line of the rake face 1 and the flank face 2. The surface formed between the rake face 1 and the side surface 5 is a surface that contacts a side wall surface of the cutting made substantially perpendicular to the cutting finish surface on both sides of the cutting finish surface made by the cutting edge 3. It is.
In particular, the one side surface 5 has a first side surface 51 near the rake surface 1 and the cutting edge 3, and a second side surface 52 that is in contact with the first side surface 51 and located behind the first side surface 51.
The angle formed by the first side surface 51 with the extending direction of the cutting blade 3 is θ1, and the angle formed by the second side surface 52 with the extending direction of the cutting blade 3 is θ2. The extending direction of the cutting edge 3 corresponds to the direction of the intersecting ridge line between the rake face 1 and the flank face 2.
Each side surface is formed such that the angle θ2 formed between the cutting edge 3 and the second side surface 52 is smaller than the angle θ1 formed between the cutting edge 3 and the first side surface 51. The angles (θ1, θ2) between the first side surface 51 and the second side surface 52 of the side surface 5 and the extending direction of the cutting edge 3 are each less than 90 degrees. Is formed so as to be inclined toward the side surface 6 opposite to the cutting tip 10c. That is, the side surface 5 (first side surface 51, second side surface 52) is inclined inward of the cutting tip 10c toward the rear in the cutting direction.

  The first side surface 51 and the second side surface 52 are inclined inwardly toward the rear in the cutting direction of the cutting tip 10c, and the first side surface 51 and the second side surface 52 are respectively angled with the extending direction of the cutting blade 3 ( According to (θ1, θ2) being less than 90 degrees, the side surface 5 is formed on both sides of the cut surface formed by the cutting edge 3 in a direction away from the cut side wall surface formed substantially perpendicular to the cut surface. Since the first side surface 51 and the second side surface 52 are released from the cutting side wall surface, the contact area between the cutting side wall surface of the object to be cut and the cutting tip 10c can be reduced. it can.

As described above, the cutting tip 10 c of the cutting tool 400 has the first flank 26 and the second flank 27 that are continuous from the cutting edge 3 in the cutting direction, and the further away from the cutting edge 3, Since the clearance angle is formed so as to increase, even when the cutting edge 3 as the cutting edge is worn, an increase in the contact area between the cutting finish surface of the cutting object and the cutting tip 10c can be suppressed.
In particular, the side surface 5 (first side surface 51, second side surface 52) of the cutting tip 10c is provided with angles (θ1, θ2) that escape and separate from the cutting side wall surface of the object to be cut. The contact area between the side wall surface and the cutting tip 10c can be further reduced.
And it becomes possible to reduce cutting resistance (excavation resistance) by suppressing contact with cutting tip 10c, and a cutting finish surface and a side wall surface of a cutting, improvement of cutting efficiency (excavation efficiency), and cutting tool 400 It is possible to extend the service life.

  Even in the cutting tool 400 including the cutting tip 10c formed with the first side surface 51 and the second side surface 52, the cutting efficiency is not rapidly deteriorated when the cutting edge of the cutting tip 10c is worn. By suppressing the contact area between the wall surface and the cutting tip 10c, the cutting efficiency can be improved and the life of the cutting tool 400 can be extended, so that suitable cutting can be performed.

(Embodiment 5)
Next, a fifth embodiment of the cutting tool according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1-4, and only a different part is demonstrated.

  As shown in FIG. 8, the cutting tool 500 includes a shaft portion 12 and a cutting portion 11 provided on the front end side of the shaft portion 12, and the cutting tip 10 d is fixed to the mounting groove 111 of the cutting portion 11. Has been.

The cutting tip 10 d has a rake face 1, a flank face 2, and a cutting edge 3 formed on a cross ridge line between the rake face 1 and the flank face 2.
In particular, as shown in FIG. 8, the flank 2 includes a first flank 28 that contacts the cutting edge 3, and a second flank 29 that contacts the first flank 26 and is located behind the first flank 28. have.
The first flank 28 has a clearance angle α8 with respect to the cut finish surface, and the second flank 29 has a clearance angle α9 with respect to the cut finish surface.
Each flank is formed such that the flank angle α9 of the second flank 29 is larger than the flank angle α8 of the first flank 28.

Further, the cutting tip 10 d has a side surface 5 and a side surface 6 on both end sides of the cutting edge 3 corresponding to the intersecting ridge line of the rake face 1 and the flank face 2. The surface formed between the rake face 1 and the side surface 5 is a surface that contacts a side wall surface of the cutting made substantially perpendicular to the cutting finish surface on both sides of the cutting finish surface made by the cutting edge 3. It is.
In particular, the one side surface 5 has a first side surface 53 near the rake face 1 and the cutting edge 3, and a second side surface 54 that is in contact with the first side surface 53 and located behind the first side surface 53.
The angle formed by the first side surface 53 with the extending direction of the cutting blade 3 is θ3, and the angle formed by the second side surface 54 with the extending direction of the cutting blade 3 is θ4. The extending direction of the cutting edge 3 corresponds to the direction of the intersecting ridge line between the rake face 1 and the flank face 2.
Each side surface is formed such that the angle θ4 formed between the cutting edge 3 and the second side surface 54 is smaller than the angle θ3 formed between the cutting edge 3 and the first side surface 53. The angles (θ3, θ4) between the first side surface 53 and the second side surface 54 of the side surface 5 and the extending direction of the cutting blade 3 are each less than 90 degrees. Is formed so as to be inclined toward the side surface 6 side opposite to the cutting tip 10d. That is, the side surface 5 (first side surface 53, second side surface 54) is inclined inward of the cutting tip 10d toward the rear in the cutting direction.

  Further, the second side surface 54 is recessed in a direction in which the angle between the second side surface 54 and the extending direction of the cutting edge 3 decreases, and is away from the cutting edge 3, and the cutting direction of the cutting tip 10 d. Three grooves 46 extending in the direction are formed. The recessed groove 46 is a recessed portion having a depth of the escape amount u 3 from the second side surface 54.

As described above, the cutting tip 10 d of the cutting tool 500 has the first flank 28 and the second flank 29 continuous from the cutting edge 3 to the rear in the cutting direction. Since the clearance angle is increased, the increase in the contact area between the cutting finish surface of the object to be cut and the cutting tip 10d can be suppressed even when the cutting edge 3 as the cutting edge is worn.
In particular, the side surface 5 (first side surface 53, second side surface 54) of the cutting tip 10d is provided with angles (θ3, θ4) that escape and separate from the cutting side wall surface of the object to be cut. The contact area between the side wall surface and the cutting tip 10d can be further reduced.
Furthermore, a concave groove 46 having a depth of the relief amount u3 is formed on the second side surface 54 of the cutting tip 10d, thereby further reducing the contact area between the cutting side wall surface and the cutting tip 10d. Can do.
And it becomes possible to reduce cutting resistance (excavation resistance) by suppressing contact with cutting tip 10d, and a cutting finish surface and a side wall surface of cutting, improvement of cutting efficiency (excavation efficiency), and cutting tool 500 It is possible to extend the service life.

  Even in the cutting tool 500 including the cutting tip 10d in which the first side surface 53 and the second side surface 54 are formed and the groove 46 is formed in the second side surface 54, the cutting edge of the cutting tip 10d is formed. Since the cutting efficiency does not deteriorate rapidly when worn, and the contact area between the cutting side wall surface and the cutting tip 10d is suppressed, the cutting efficiency can be improved and the life of the cutting tool 500 can be extended. Suitable cutting is possible.

  In the above embodiment, three flank surfaces (first flank surface 21, second flank surface 22, and third flank surface 23) are formed on the cutting tip 10 of the first embodiment. For example, the cutting tip 10 is provided with at least two flank surfaces, that is, the first flank 21 and the second flank 22. It only has to be. Also, four or more flank surfaces may be formed.

  Moreover, in the above embodiment, the flank (24, 25) and the groove (44, 45) were formed as two flank elements in the cutting tip 10a of the second embodiment and the cutting tip 10c of the third embodiment. However, the present invention is not limited to this. For example, the flank (first flank 21, first flank 21) of a cutting tip (for example, the cutting tip 10 of Embodiment 1) in which two or more flank surfaces are formed. A concave groove may be formed in either the second flank 22 or the third flank 23). That is, when there are a plurality of flank surfaces, a concave groove may be formed in at least one of the flank surfaces.

Further, the cutting tip is not limited to the differential blade type fixed to the mounting groove 111 of the cutting part 11, but may be a tension blade type fixed to one side part of the cutting part 11.
Further, the flank is not limited to a flat surface but may be a curved surface.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

It is a side view which shows the cutting tool which concerns on this invention. It is a front view which shows the cutting tool from the arrow II direction of FIG. It is an enlarged view of the cutting tip part of a cutting tool. It is explanatory drawing which shows the magnitude of the load concerning a cutting tip. It is a side view which shows the cutting tool in Embodiment 2 of this invention, and explanatory drawing which shows the cutting tip from the arrow V direction in the figure. It is a side view which shows the cutting tool in Embodiment 3 of this invention, and explanatory drawing which shows the cutting tip from the arrow VI direction in a figure. It is a side view which shows the cutting tool in Embodiment 4 of this invention, and explanatory drawing which shows the cutting tip from the arrow VII direction in the figure. It is a side view which shows the cutting tool in Embodiment 5 of this invention, and explanatory drawing which shows the cutting tip from the arrow VIII direction in the figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rake face 2 Flank 21 First flank 22 Second flank 23 Third flank 3 Cutting edge 10 Cutting tip 11 Cutting part 12 Shaft part α1, α2, α3 Clearance angle 100 Cutting tool 10a Cutting tip 24 Flank 44 Concave groove
α4 relief angle u1 relief amount 200 cutting tool 10b cutting tip 25 relief surface 45 concave groove (concave portion)
α5 relief angle u2 relief amount 300 cutting tool 10c cutting tip 26 first relief surface 27 second relief surface 5 side surface 51 first side surface 52 second side surface α6, α7 relief angle θ1, θ2 angle 400 cutting tool 10d cutting tip 28 first Flank 29 Second Flank 46 Groove (concave)
53 First side 54 Second side α8, α9 Clearance angle θ3, θ4 angle u3 Relief amount 500 Cutting tool

Claims (7)

A cutting tool comprising: a shaft portion connected to a predetermined excavation device; and a cutting portion provided on the front end side of the shaft portion and in contact with the ground,
The cutting portion is provided with a cutting tip having a rake face, a flank face, and a cutting edge that is formed at an intersecting ridge line of the rake face and the flank face and substantially perpendicular to the cutting direction,
The flank has a first flank that contacts the cutting edge and a second flank that contacts the first flank and is positioned behind the first flank, and the flank angle of the first flank A cutting tool characterized in that the clearance angle of the second flank is larger.   2. The cutting tool according to claim 1, wherein the flank has at least one recess that is recessed in a direction in which the flank angle increases and extends in a direction away from the cutting edge. A cutting tool comprising: a shaft portion connected to a predetermined excavation device; and a cutting portion provided on the front end side of the shaft portion and in contact with the ground,
The cutting portion is provided with a cutting tip having a rake face, a flank face, and a cutting edge that is formed at an intersecting ridge line of the rake face and the flank face and substantially perpendicular to the cutting direction,
The cutting tool, wherein the flank is recessed in a direction in which a flank angle of the flank increases, and at least one recess extending in a direction away from the cutting edge is formed.   The cutting tool according to any one of claims 1 to 3, wherein at least one of the side surfaces of the cutting tip intersects with the extending direction of the cutting blade at an angle of less than 90 degrees.   The side surface has a first side surface close to the cutting edge and a second side surface positioned rearward of the first side surface, and the cutting edge is formed from an angle formed by the extending direction of the cutting edge and the first side surface. The cutting tool according to claim 4, wherein an angle formed between the extending direction of the blade and the second side surface is smaller.   The at least one recessed part extended in the direction spaced apart from the said cutting blade is formed in the said side surface in the direction where the angle made with the extending direction of the said cutting blade becomes small, It is characterized by the above-mentioned. The cutting tool according to 4 or 5.   The cutting tip is fixed to the attachment groove on the tip side of the cutting part, and the length of the cutting tip from the opening end of the attachment groove to the cutting edge with respect to the width of the side surface along the cutting direction of the cutting tip. The cutting ratio according to any one of claims 1 to 6, wherein the ratio is not less than 50% and less than 125%.

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