JP2020001098A - Saw blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a saw blade from which cutting chips are satisfactorily discharged. SOLUTION: A saw blade (51) has a plurality of teeth (1) repeatedly formed in a moving direction during cutting and exhibits a band shape. The saw blade (51) has a rake face (11a1) and a rake face (11a1) in which at least one of the plurality of teeth (1) is formed with a negative rake angle of -50 ° or more and -20 ° or less. ) And the tooth bottom (13) intersect with the virtual plane (LNb) including the rake face (11a1), and the angle of 145 ° or more and 170 ° or less with respect to the movement direction so that the tooth root side is the front side of the movement direction. It has a contact surface (14a) and. [Selection diagram] Fig. 2

Description

  The present invention relates to saw blades.

Patent Literature 1 describes a band saw blade that curls a cutting chip cut out by cutting and easily discharges the cutting chip to the outside from a gullet that is a space between two adjacent teeth.
Patent Literature 2 discloses a saw blade having a chamfer at the tip of a tooth.

Japanese Patent No. 3283572 Utility Model Registration No. 2603636

  The band saw blade described in Patent Literature 1 has an arc-shaped cutting guide surface connected to a rake face as a tooth surface shape for curling cutting chips. The cutting chips cut out by cutting move along the arc-shaped cutting guide surface in a state of high temperature due to heat generated by the cutting resistance, and thus curl. Curled cuttings are less likely to clog the gullet and are easily discharged.

Generally, in a tooth surface shape having a cutting guide surface, the rake angle of the rake face is 0 ° or a positive value. Thereby, the cut chips are easily guided to the cutting guide surface.
The rake face having a rake angle of 0 ° is a face orthogonal to the traveling direction of the saw blade. A rake face having a positive rake angle is a face that is inclined rearward in the direction opposite to the traveling direction of the saw blade from the tooth tip toward the tooth root.

In recent years, the band sawing machine has been increased in size, increased in rigidity, and increased in horsepower, so that cutting speed has been increased in cutting of iron-based materials mainly composed of low carbon steel.
As the cutting speed increases, the possibility that the annular band saw blade is slightly chipped at the sharp tooth tip (chipping) increases. Therefore, the annular band saw blade has a chamfered portion as described in Patent Literature 2 on the tooth tip, or has a rake face having a negative rake angle.

  However, if a chamfer is formed at the tooth tip or a rake face with a negative rake angle is formed, the cutting chips are cut out along the chamfer or the rake face, and are not guided to the cutting guide face, and are not guided to the cutting guide face. At a large angle. Therefore, the cutting chips are alternately bent so as to fold and overlap without being curled, and are clogged in the gullet, which may cause a problem in discharge from the gullet or a loss of the tooth tip.

  Therefore, an object to be solved by the present invention is to provide a saw blade from which cutting chips are satisfactorily discharged.

In order to solve the above problems, the present invention has the following configuration.
1) a belt-like shape having a plurality of teeth repeatedly formed in a moving direction at the time of cutting,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
A contact surface that intersects with a virtual plane including the rake face between the rake face and the tooth bottom and forms an angle of 145 ° or more and 170 ° or less with respect to the movement direction such that the root side is the front side in the movement direction. When,
A saw blade having
2) a belt-like shape having a plurality of teeth repeatedly formed in a moving direction at the time of cutting,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
Between the rake face and the tooth bottom, an abutment face inclined at an angle of more than 0 ° and 60 ° or less with an imaginary plane including the rake face while the dedendum side is inclined forward of the moving direction,
A saw blade having
3) The contact surface extends in a front side and a rear side with respect to a position intersecting with the virtual plane, and is formed in a range of at least 2 mm or more in the moving direction, 1) or 2). The saw blade.
4) The saw blade according to any one of 1) to 3), wherein the tooth height is 3 mm or more and 10 mm or less.
5) a disk having a plurality of teeth repeatedly formed in the outer peripheral portion in the circumferential direction,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
An angle of 145 ° or more and 170 ° or less with respect to a tangent line at the reference position such that the imaginary plane including the rake face intersects at the reference position between the rake surface and the tooth bottom, and the root side is the front side in the cutting direction. And the contact surface
A saw blade having
6) A disk shape having a plurality of teeth repeatedly formed in the outer peripheral portion in the circumferential direction,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
Between the rake face and the tooth bottom, an abutment surface that is inclined so that the root side is the front side in the cutting direction and intersects with an imaginary plane including the rake face at an angle of more than 0 ° and 60 ° or less,
A saw blade having

  ADVANTAGE OF THE INVENTION According to this invention, the effect that cutting waste is discharged | emitted favorably is acquired.

FIG. 1 is a side view showing a band saw blade 51 which is an example of the saw blade according to the embodiment of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a graph showing the relationship between the rake angle θA and the chatter occurrence rate. FIG. 4 is a graph showing the relationship between the rake angle θA and the cutting force. FIG. 5 is a side view for explaining a generation state of the cutting waste Wt. FIG. 6 is a graph showing the relationship between the contact angle θB and the non-curling rate of the cutting waste Wt. FIG. 7 is a side view showing a band saw blade 51A of a modification.

(Example)
An example of the saw blade according to the embodiment of the present invention will be described using a band saw blade 51.
FIG. 1 is a side view showing a part of the band saw blade 51.
The band saw blade 51 is formed in an annular shape, and is mounted on a band saw machine to circulate and move to cut a workpiece.
The band saw blade 51 has a band-shaped body portion 511 and a tooth portion 512 including a plurality of teeth 1 repeatedly formed on one edge in the width direction of the body portion 511.
The band saw blade 51 used for a high-performance band sawing machine generally has a total width of 54 mm or 67 mm including the body portion 511 and the tooth portion 512 and a thickness of 1.6 mm.

As shown in FIG. 1, the width direction length of the body portion 511 is defined as a body width Hw, and the width direction length of the tooth portion 512 is defined as a tooth height Hb.
For convenience of description, a virtual reference line LN51 extending in the longitudinal direction is set at the center in the width direction of the trunk width Hw. The reference line LN51 and the end surface 513 of the body portion 511 on the opposite side of the tooth portion 512 are parallel.
A valley-shaped portion between two adjacent teeth 1 and 1 becomes a gullet G.

FIG. 2 is an enlarged view of a portion A including two adjacent teeth 1, 1 shown in FIG.
The direction of movement of the band saw blade 51 for circulating movement on the band saw machine is indicated by an arrow DRa. The front and rear directions in the moving direction are also appended to the arrow DRa. The moving direction is the cutting direction of the saw blade 51.

A hard cutting tip 11 is joined to the tip of the tooth 1 by welding. The cutting tip 11 is formed into a predetermined cutting edge shape by polishing.
The bottom 13 of the gullet G between the two adjacent teeth 1 and 1 is the edge of the trunk 511 on the side of the tooth 512.

The cutting tip 11 has a chamfered portion 11a formed at a tip end portion. The tip 11t of the chamfer 11a is located at a tooth height Hb from the tooth bottom 13.
The chamfered portion 11a is formed to have a chamfered surface 11a1 that is inclined forward in the traveling direction (arrow DRa) from the tooth tip side toward the root side.
The chamfered surface 11a1 is substantially a rake surface in cutting. Therefore, the angle θA, which is the inferior angle between the chamfered reference plane LNb, which is a virtual plane including the chamfered surface 11a1, and the orthogonal reference plane LNv orthogonal to the reference line LN51, is a rake angle of a negative value (−). I have. Hereinafter, the angle θA is referred to as a rake angle θA for convenience. The chamfered surface 11a1 is also referred to as a rake surface 11a1.

  In the shape of the cutting tip 11, the rear side from the tip 11t is a flank 11c that is inclined so as to approach the body 511 side, and is substantially parallel to the orthogonal reference plane LNv from the chamfered part 11a to the body 511 side. The chip front surface 11b is used.

The tooth 1 has a connecting portion 12, a connecting portion 15a, a contact portion 14, and a connecting portion 15b from the cutting tip 11 side in an outer shape connecting the cutting tip 11 and the tooth bottom portion 13. The connecting portions 15a and 15b are portions each having a smooth curve in a side view, and suppress concentration of stress when a force is applied to the tooth portion 512.
The connecting portion 12 has a connecting surface 12a substantially along the orthogonal reference plane LNv as an end surface, and the abutting portion 14 has an abutting surface 14a which extends as an end surface so that the front side is inclined so as to approach the tooth bottom portion 13. .
As shown in FIG. 2, the tooth bottom 13 is formed parallel to the reference line LN51. A plane that includes the root 13 and is parallel to the reference line LN51 and orthogonal to the paper surface is referred to as a root reference plane LN13.

The contact surface 14a of the contact portion 14 is formed as follows.
First, an abutment position reference plane LNa is set at a position spaced a predetermined distance Ha from the tooth bottom reference plane LN13 toward the tooth tip in parallel with the tooth bottom reference plane LN13.
Next, in side view, an intersection between the contact position reference plane LNa and the chamfer reference plane LNb including the chamfered surface 11a1 is determined and set as the contact part reference position P1.
A plane that forms an obtuse angle θB in the counterclockwise direction in FIG. 2 with respect to the abutment position reference plane LNa around the abutment part reference position P1 is set as the abutment surface 14a.

  The contact surface 14a is formed such that, in a side view, a range of a distance La including at least the contact portion reference position P1 in the direction in which the reference line LN51 extends becomes a plane. Therefore, the distance Ha is set so that at least the connecting portion 15b can be formed.

As described later, the contact portion reference position P1 may be located at the center of the distance La. Further, the distance La may be set to 2 mm or more.
Therefore, the distance Ha may be set such that the contact portion reference position P1 is 1 mm or more in the direction in which the reference line LN51 extends from the connection point P3 between the contact surface 14a and the connecting portion 15b in a side view.

  In the shape of the tooth 1 described above, the rake angle θA is set within the range α of −50 ° to −20 °. The contact angle θB is set within a range β of 145 ° to 170 °.

First, the range α of the rake angle θA will be described in detail with reference to FIGS.
FIG. 3 is a graph showing the relationship between the rake angle θA (°) in the negative value region and the chatter occurrence rate (%) in cutting. The conditions for cutting and measurement are as follows.
Material to be cut: SUJ3 (high carbon chromium bearing steel) Round bar Diameter 200 (mm)
Cutting speed: 200 (m / mim)
Cutting rate: 400 (cm ² / mim)
Number of measurements: average of four cuts

FIG. 4 is a graph showing the relationship between the rake angle θA (°) in the negative value region and the cutting force (× 10 ³ N). The conditions for cutting and measurement are as follows.
Material to be cut: S45C (Carbon steel for machine structure) Round bar Diameter 250 (mm)
Cutting speed: 60 (m / mim)
Cutting rate: 200 (cm ² / mim)
Number of measurements: average of 5 cuts

As shown in FIG. 3, the smaller the rake angle θA is as a negative value (the larger the absolute value of the negative value), the lower the chatter occurrence rate. Therefore, the smaller the rake angle θA is, the more preferable it is as a negative value. In particular, when the angle is −20 ° or less, the chatter occurrence rate is more preferably 30% or less.
On the other hand, as shown in FIG. 4, as the rake angle θA is smaller as a negative value (the absolute value of the negative value is larger), the cutting resistance is increased, and therefore, the rake angle θA is more preferably as a negative value. Since the cutting force sharply increases particularly when the rake angle θA is −55 ° or less, the cutting resistance is preferably -50 ° or more.
These results are similarly obtained if the material to be cut is an iron-based material.

  From these results, the rake angle θA may be set in the range α of −50 ° or more and −20 ° or less.

FIG. 5 is a side view for explaining a generation state of the cutting waste Wt when cutting the workpiece W using the band saw blade 51. The traveling direction (arrow DRa) of the band saw blade 51 is the left direction.
The band saw blade 51 used has a rake angle θA of −30 ° within the range α and a contact angle θB of the contact surface 14a of 150 ° within the range β.

The cutting waste Wt shaved off by the chamfered surface 11a1 is cut out along the chamfered surface 11a1 (arrow DRb).
The contact surface 14a intersects the chamfer reference plane LNb including the chamfer surface 11a1 at the contact portion reference position P1 at the contact angle θC.
In this example, the contact angle θC is such that the rake angle θA is −30 ° and the contact angle θB is 150 °,
Contact angle θC = θB− | θA | −90 = 150−30−90 = 30 (°)
Is required.

The cutting waste Wt cut out by the tooth 1 is cut out in a direction along the chamfered surface 11a1 (see the arrow DRb), and the angle formed by the contact surface 14a with the contact surface 14a at the contact position P2 is substantially equal to the contact angle. Contact as θC.
The contact angle θC is 30 °, and is a so-called thin contact angle at which the cutting waste Wt contacts the contact surface 14a in a relatively prone position. Therefore, after the cutting waste Wt abuts on the contact surface 14a, the cutting waste Wt smoothly moves while bending, and becomes curled (arrow DRc).

  The range β, which is the range of the contact angle θB at which the cutting waste Wt is well curled, was clarified by experiments. Since the range β has been clarified, the range γ of the contact angle θC corresponding to the range β can also be obtained.

  FIG. 6 is a graph showing the relationship between the contact angle θB of the contact surface 14a and the non-curl rate of the cutting waste Wt when the rake angle θA is −45 °. The non-curling ratio is a ratio of the number of curl generation failures to a predetermined generation number of the cutting waste Wt, and is obtained by observing an image of a cutting waste generation state during cutting.

  In the actual cutting process, even if all of the cutting chips Wt are not curled, if the half of them are curled, they are discharged relatively well from the gullet G without clogging. That is, the non-curling rate is preferably less than 50%. The conditions for cutting and measuring to obtain the results shown in FIG. 6 are as follows.

Material to be cut: SUJ3 (high carbon chromium bearing steel) Round bar Diameter 200 (mm)
Rake angle θA: -45 °
Cutting speed: 200 (m / mim)
Cutting rate: 400 (cm ² / mim)
Number of measurements: average of four cuts

As shown in FIG. 6, when the contact angle θB is in the range β of 145 ° to 170 °, the non-curling rate is 40% or less, and the discharge of the cutting waste Wt due to curling is stably improved. Further, when the contact angle θB was in the range β2 of 150 ° to 164 °, the non-curling rate was 20% or less, and the discharge of the cutting waste Wt was further improved.
In a further experiment, if the contact angle θB is within the range β, the non-curl rate becomes less than 50%, that is, the curl rate becomes 50% or more, regardless of the value of the rake angle θA within the range α. It became clear that the discharge of the cutting waste Wt was improved.

Next, curling of the cutting waste Wt will be described from the viewpoint of the contact angle θC of the cutting waste Wt abutting on the contact surface 14a.
The curl rate of the cutting waste Wt depends on the contact angle θC. That is, the good degree of discharge of the cutting waste Wt from the gullet G depends on the contact angle θC.
When the rake angle θA is within the range α and the contact angle θB is within the range β, the maximum value θC1 of the contact angle θC is -20 ° which is the maximum value of the rake angle θA of the range α, and the contact angle θB is within the range. It is obtained when the maximum value of β is 170 °. On the other hand, the minimum value θC2 of the contact angle θC is obtained when the rake angle θA is −50 ° which is the minimum value of the range α, and the contact angle θB is 145 ° which is the minimum value of the range β.

That is,
Maximum value θC1 = θB− | θA | −90 = 170−20−90 = 60 (°)
Minimum value θC2 = θB− | θA | −90 = 145-50−90 = 5 (°)
Becomes

  As the contact angle θC is farther from 90 ° and closer to 0 °, the cutting waste Wt comes into contact with the inclined posture closer to the contact surface 14a, so that it is obvious that the cutting waste Wt is easily curled. Therefore, if the rake angle θA is within the range α and the contact angle θB is within the range β, the cutting waste Wt abuts on the contact surface 14a in the range γ where the contact angle θC is more than 0 ° and 60 ° or less. Thereafter, the curling is favorably performed along the surface of the connecting portion 15b from the contact surface 14a.

The contact position P2 substantially coincides with the contact portion reference position P1 in an ideal situation without variation. However, in actual cutting, the contact position P2 may be shifted from the contact portion reference position P1 due to a variation in the cutting direction of the cutting waste Wt.
From the above observation of the state of the generation of the cutting chips, it was confirmed that the contact position P2 fluctuates before and after in the traveling direction of the band saw blade 51 due to the variation in the cutting direction of the cutting chips Wt. The amount of variation was 1 mm or less in each of the front and rear directions, and the variation in position was almost normally distributed around the contact portion reference position P1.
For this reason, the contact surface 14a has, for example, a range in which the distance La is 2 mm, which is 1 mm in each of the forward direction and the backward direction of the traveling direction, with respect to the contact portion reference position P1, and extends at least as a plane having the contact angle θB. It is good to be formed.

The band saw blade 51 described in detail above has a hard cutting tip 11 at the tooth tip. The cutting tip 11 has a rake face 11a1 (chamfered face 11a1) formed with a negative rake angle θA. A contact surface 14a is formed between the rake face 11a1 and the tooth bottom 13 so as to intersect with the chamfer reference plane LNb including the rake face 11a1 at a contact angle θC. The contact surface 14a forms an obtuse angle θB with respect to the traveling direction of the band saw blade 51.
Here, the rake angle θA is set in a range α of −50 ° or more and −20 ° or less, and the contact surface 14a has a contact angle θB in a range β of 145 ° or more and 170 ° or less, or a contact angle θC of 0 °. Is set to be in a range γ of more than 60 ° or less.

  By setting the rake angle θA within the range α, the chatter occurrence rate and the cutting resistance are reduced. Further, since the contact angle θB is within the range β or the contact angle θC is within the range γ, the curl rate of the cutting chips Wt is high, and the cutting chips Wt are favorably discharged from the gullet. You.

  The embodiment of the present invention is not limited to the above-described configuration, and may be modified without departing from the gist of the present invention.

Instead of the band saw blade 51, a modified band saw blade 51A having no cutting tip 11 may be used.
FIG. 7 is an enlarged side view including two adjacent teeth 1A, 1A of the band saw blade 51A, and is a view corresponding to FIG. In the tooth 1A, the cutting tip 11 is not joined to the tip, and a rake face 1Aa having a rake angle θA is formed at the tooth tip. Other shapes and dimensional relationships are the same as those of the band saw blade 51.
The band saw blade 51A also has the same effect as the band saw blade 51.

In the band saw blade 51 shown in FIG. 1, from the viewpoint of securing the strength, the tooth height Hb is set to be less than 20% of the total width so that the trunk width Hw is equal to or more than 80% of the total width of the trunk width Hw + the tooth height Hb. Good. This is the same for the band saw blade 51A.
Since the entire width of the band saw blade 51 is 54 mm or 67 mm as described above, the tooth height Hb is preferably set to 10 mm or less.
Further, as shown in FIG. 1, the maximum diameter when the cutting waste Wt is appropriately curled is the diameter Dt of the circle Ct that is in contact with the tooth tip line LNt and the tooth bottom 13. This diameter Dt is equal to the tooth height Hb.

From experience, clogging is likely to occur when the cross-sectional area Sb in side view of cutting by one feed by the tooth 1 exceeds 70% of the area St in the maximum diameter in side view occupied by the curled cuttings Wt. It is understood that it becomes.
That is, it is preferable that the removal sectional area Sb ≦ the area St × 0.7.
Here, the area St = (tooth height Hb) ² × π / 4.
Further, assuming that the feed amount in the cutting of the band saw blade 51 is 0.03 mm in general mild steel cutting and the cutting length for one feed of the workpiece is 150 mm, the removal sectional area Sb of the workpiece is 0.1 mm. 03 × 150 (mm ² ).
Therefore,
Tooth height Hb ≧ (0.03 × 150 × (π / 4) × 0.7) ^0.5 = 2.86
Becomes Thereby, when the tooth height Hb is at least 3.0 mm or more, clogging is less likely to occur and good discharge is promoted.
As described above, the tooth height Hb is preferably 10 mm or less from the viewpoint of strength. From these, it is preferable that the depth of the gullet G in the band saw blade 51 having the abutting portion 14 is set to be 3.0 mm or more and 10 mm or less. This is the same for the band saw blade 51A.
Further, the band saw blades 51 and 51A are not limited to those in which all the teeth have the abutting portions 14. Of the plurality of teeth 1 included in the band saw blades 51 and 51A, the necessary teeth 1 may have the abutting portions 14. That is, the band saw blades 51 and 51A only need to have at least one of the plurality of teeth 1 having the abutting portion 14.

Although the band saw blade 51 and the band saw blade 51A have been described as examples and modifications of the saw blade according to the embodiment of the present invention, the saw blade may be a disk-shaped circular saw blade.
In the case of a circular saw blade, the reference line LN51 is not a straight line but a circle. Also, the contact position reference plane LNa is a circle concentric with the diameter larger than the reference line LN51, the tooth bottom 13 is a surface extending in an arc shape, and the contact angle θB is an angle between the contact line reference position P1 and a tangent at the contact part reference position P1a. Can be similarly set.
Further, all of the plurality of teeth repeatedly formed in the circumferential direction on the outer peripheral portion of the saw blade may not have the above-mentioned abutting portion 14, and may have some of the plurality of teeth. .

1, 1A tooth 1Aa rake face 11 cutting tip 11a chamfered part, 11a1 chamfered face 11b chip front face, 11c flank face, 11t tip part 12 connection part, 12a connection face 13 tooth bottom part 14 contact part, 14a contact surface 15a. 15b Connecting portion 51, 51A Band saw blade 511 Body, 512 Tooth, 513 End face Ct Circle Dt Diameter G Gallet Ha Distance, Hb Tooth height, Hw Body width La Distance LNa Contact position reference surface, LNb Chamfer reference surface, LNt Tooth tip Line LNv Orthogonal reference plane, LN51 reference line, LN13 Root bottom reference plane P1 Contact part reference position, P2 contact position, P3 Connection point Sb Removal cross-sectional area, St Area W Work material, Wt Cutting waste θA Rake angle (angle) , ΘB contact angle θC contact angle, θC1 maximum value, θC2 minimum value α, β, β2, γ (angle) range

Claims (6)

A belt shape having a plurality of teeth repeatedly formed in a moving direction at the time of cutting,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
A contact surface that intersects with a virtual plane including the rake face between the rake face and the tooth bottom and forms an angle of 145 ° or more and 170 ° or less with respect to the movement direction such that the root side is the front side in the movement direction. When,
With a saw blade. A belt shape having a plurality of teeth repeatedly formed in a moving direction at the time of cutting,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
Between the rake face and the tooth bottom, an abutment face inclined at an angle of more than 0 ° and 60 ° or less with an imaginary plane including the rake face while the dedendum side is inclined forward of the moving direction,
With a saw blade.   The said contact surface extends in the front side and the back side with respect to the position which intersects with the said virtual plane, and is formed in the range of at least 2 mm or more in the said movement direction, The Claim 1 or Claim 2 characterized by the above-mentioned. Saw blade.   The saw blade according to any one of claims 1 to 3, wherein the tooth height is 3 mm or more and 10 mm or less. A disk shape having a plurality of teeth repeatedly formed in the outer peripheral portion in the circumferential direction,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
An angle of 145 ° or more and 170 ° or less with respect to a tangent at the reference position such that the imaginary plane including the rake face intersects at the reference position between the rake surface and the tooth bottom, and the root side is the front side in the cutting direction. And the contact surface
With a saw blade. A disk shape having a plurality of teeth repeatedly formed in the outer peripheral portion in the circumferential direction,
At least one tooth of the plurality of teeth,
A rake face formed at a negative rake angle of -50 ° or more and -20 ° or less;
Between the rake face and the tooth bottom, an abutment face that is inclined so that the root side is the front side in the cutting direction and intersects with an imaginary plane including the rake face at an angle of more than 0 ° and 60 ° or less,
With a saw blade.

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