JPH1071522A - Rotary cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a contact area of a base metal part to air and cool the base metal part as low as possible in cutting by continuously providing a tip part having a plurality of tips in the circumferential edge part of the disc metal base part and providing a plurality of recessed parts in the intermediate part of the central hole of the metal base part and the tip part. SOLUTION: A tip saw 10 is basically constituted of a disc metal base part 12 and a tip part 14 formed around its outer circumferential part, and the tip part 14 is composed of a plurality of expanded parts 16 which are separated from each other by a prescribed angle and projected outward and a plurality of tips 18 which are fixed to their one ends respectively and provided with edges on the tips. Concentric circumferential grooves 24a-24j are provided in an intermediate part between the central hole 20 of the metal base part 12 and the tip part 14 in both sides so that the area in contact with air becomes larger compared with a case of forming the intermediate part into a plane. As a result, the heat radiation action from the metal base part 12 is favorably implemented so that the metal base part 12 and/or the tip part 14 are prevented from expanded by frictional heat generated in cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotary cutting tool such as a circular saw and a tip saw.

[0002]

2. Description of the Related Art For example, a rotary cutting tool such as a circular saw has been used in order to machine a workpiece such as wood into a plate shape or a block shape. The rotary cutting tool is connected to a rotary drive source such as an engine or a motor, and is rotated at a high speed by energizing the rotary drive source, and cuts a workpiece by a thin continuous cutting blade.

[0003]

However, at the time of this cutting, since the continuous cutting blade and / or the base metal comes into contact with a part of the work, frictional heat is generated on the cutting blade and / or the base metal. I do. This frictional heat causes the base metal to expand in the circumferential and radial directions or in the thickness direction. As a result, the base metal or the cutting blade is distorted, and the cutting ability is reduced. Further, the processing accuracy is deteriorated, the noise is generated, and the durability is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned disadvantages. A plurality of recesses are provided in a base metal portion, thereby increasing the contact area of the base metal portion with air to cut a workpiece. It is an object of the present invention to provide a rotary cutting tool configured to sometimes cool the base portion as much as possible.

[0005]

In order to achieve the above-mentioned object, the present invention comprises a disk-shaped base portion and a plurality of cutting blades formed continuously on a peripheral portion of the base portion. Cutting edge,
A central hole is formed at the center of the base portion, the center hole being attached to a rotation shaft of a rotary drive source, and the base portion is provided at an intermediate portion between the center hole and the cutting blade portion. A plurality of recesses are provided.

According to the present invention, the center hole of the base portion constituting the rotary cutting tool is axially mounted on the rotary drive source, and the rotary drive source is urged, so that the rotary cutting tool can be moved relative to the workpiece. Start cutting. As the cutting process progresses, frictional heat may be generated between the workpiece and the base portion and / or the cutting edge portion. At this time, the base portion is provided by a plurality of recesses provided in the base portion. Since the metal part has a sufficiently large contact area with air, the base metal part is suitably cooled.

Further, since the concave portion is formed as a circumferential groove composed of multiple concentric circles, noise during cutting is reduced, and no abnormal noise is generated. Therefore, the rotary cutting tool according to the present invention has a long service life, does not deteriorate the working environment, and does not cause an error in the processing dimensions.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a rotary cutting tool according to the present invention will be described below in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 denotes a tip saw according to an embodiment of the present invention. This tip saw 1
0 is basically composed of a disk-shaped base 12 and a cutting edge 14 formed on the outer peripheral edge of the base 12.
The cutting blade portion 14 includes a plurality of bulging portions 16 that are spaced apart from each other by a predetermined angle and protrude outward, and a plurality of tips 18 that are respectively fixed to one end of the bulging portion 16 and have a cutting blade at a tip.
Consists of In this case, the base portion 12 and the bulging portion 1
6 is integrally formed by cutting or forging such as pressing of a metal material.

A central hole 2 is provided at the center of the base 12 through a fixing means (not shown).
0 is formed. A plurality of slits 22a extending radially from the outer peripheral edge of the base 12 toward the center hole 20;
22j are formed, and the slit 22 having a curved shape is formed.
a to 22j in the radially outward direction are adjacent to the bulging portion 1
6. In addition, the plurality of slits 22a to 22j are two types of large and small slits 22.
a to 22j are alternately arranged in a ring shape.

The center hole 20 of the base 12 and the cutting blade 14
In the middle part of the above, there are ten concentric circumferential grooves 24a-
24j are formed. The circumferential grooves 24a to 24j
Is formed at a predetermined part of an intermediate portion between the center hole 20 and the cutting edge portion 14 and comes into contact with air as compared with a case where the intermediate portion between the center hole 20 and the cutting edge portion 14 is formed in a plane. It is configured to have a large area. As shown in FIG. 12, multiple concentric circumferential grooves 24 are formed in the center hole 20.
May be formed over substantially the entire surface of the intermediate portion between the cutting blade 14 and the cutting blade 14.

In this case, the circumferential grooves 24a to 24j are
As shown in FIG. 2, the circumferential grooves 2 are provided on both the front surface and the back surface of the base portion 12 and have different diameters from the circumferential grooves 24 a to 24 j formed on the front surface of the base portion 12.
6a to 26j are formed on the back surface. The circumferential groove 2
The shapes of 4a to 24j (26a to 26j) are formed in a semicircular cross section, and the circumferential grooves 24a to 24j (2
6a to 26j) are provided alternately on the front and back sides of the base 12 (see FIG. 2).

The tip saw 10 according to the present embodiment is basically configured as described above, and its operation and effect will be described below.

The tip saw 10 is connected to a rotary shaft of a rotary drive source (not shown) through a center hole 20. When the rotational drive source is energized, the tip saw 10 starts rotating by the rotational force transmitted from the rotational drive source,
By pressing the cutting blade portion 14 against an object to be cut such as wood (not shown), the cutting process is performed. As the cutting process progresses, frictional heat may be generated between the cutting surface of the workpiece and the base 12 and / or the cutting edge 14.

Although there is a concern that the frictional heat may cause expansion of the base portion 12 in the circumferential direction, even in such a situation, the circumferential gap between the plurality of slits 22a to 22j is narrow. Thus, no distortion occurs in the base portion 12 and / or the cutting edge portion 14.

In the course of this cutting, the side surfaces of the base 12 forming the circumferential grooves 24a to 24j (26a to 26j) perform a heat radiation function. That is, the circumferential groove 24a
-24j (26a-26j) are engraved around the base 12 concentrically, so that the contact area of the base 12 with air substantially increases. As a result,
The heat dissipating action from the base portion 12 is favorably performed, and expansion due to frictional heat generated in the base portion 12 and / or the cutting blade portion 14 during cutting can be avoided. In addition, since the circumferential grooves 24a to 24j (26a to 26j) are configured concentrically, the wind noise particularly when coming into contact with air is not so loud, and does not lower the cutting function. Furthermore, no abnormal noise occurs during cutting.

Here, the groove shape of the circumferential groove will be described. In FIG. 2, the circumferential grooves 24a to 24c and the circumferential grooves 26a to 26
j are alternately arranged.
A decrease in strength due to a decrease in the thickness can be minimized. Further, as shown in FIG. 3, circumferential grooves 24a to 24j having the same diameter as the circumferential grooves 24a to 24j formed on the surface of the base metal part 12 may be formed on the back surface.

Further, the circumferential grooves 24a to 24j (26
a to 26j) may be simply grooves having a semicircular cross section,
For example, as shown in FIG.
Dovetail groove 28a orbiting instead of 24j (26a-26j)
To 28j (30a to 30j) or a circumferential groove 32 having a substantially V-shaped cross section as shown in FIG.
a to 32j (34a to 34j). By changing the cross-sectional shape to a shape like the dovetail grooves 28a to 28j (30a to 30j), the contact area with air is further increased, and the heat radiation effect can be further enhanced.

As described above, in the present embodiment, the circumferential grooves 24a to 24j (26a to 26j) having various cross-sectional shapes are provided.
j), 32a to 32j (34a to 34j) and the dovetail grooves 28a to 28j (30a to 30j), but the present invention is not limited to this. Needless to say, it is sufficient to provide a plurality of recesses for increasing the contact area with air at an intermediate portion with the cutting blade portion 14.

Next, the tip saw 10 (hereinafter referred to as tip saw A) according to the present embodiment shown in FIG.
The following experiment was performed using a chip saw (hereinafter, referred to as chip saw B) in which the front and rear surfaces of the base metal part 12 are flat without the metal parts 24j (26a to 26j). Note that the tip saws A and B have an outer diameter of 305 mm, a diameter of the center hole 20 of 25.4 mm, and a thickness of the base portion 12 of 2.0 mm, and are formed to have the same dimensions. Further, the circumferential grooves 24a to 24j (2
6a to 26j) are formed in ten concentric circles, and the circumferential grooves 24a to 24j (26a to 26j) are formed with a width of about 40 mm between a radius of about 85 mm and a radius of about 125 mm from the center. .

The tip saw A is rotated in the direction of the arrow under the driving action of a rotary drive source (not shown), and a piece of wood is pressed against one side of the rotating tip saw A to generate frictional heat, and the piece of wood is pressed against the tip saw A. After 30 seconds, the friction state was detected (see FIG. 6). Subsequently, the same experiment as that for the tip saw A was performed for the tip saw B, and a friction state 30 seconds after the wood piece was pressed against the tip saw B was detected (see FIG. 7).

FIGS. 8A to 8D show the results of this experiment. 8B and 8D are thermal images of tip saw A, and FIGS. 8A and 8C are thermal images of tip saw B. This thermal image shows the level of the frictional heat temperature by shading the color, and shows that the temperature increases as the black color becomes darker.

In this experiment, the rotation speed of the rotary drive source was changed, and in FIGS. 8A and 8B, the rotation speed was set to 120.
0 rpm, and the rotation speed is 24 in FIGS. 8C and 8D.
It was set to 00 rpm. The dimensions of the contact surfaces of the pieces of wood pressed against the tip saws A and B are 40 mm ×
As shown in FIG. 9, the experiment was performed in a state where the wood piece was in contact with the tip saw A (B) and the wood piece was displaced by 0.4 mm toward the tip saw A (B) as shown in FIG.

8A and 8B, and FIGS. 8C and 8D, the circumferential grooves 24a to 24
j (26a to 26j) is not formed, and the circumferential groove 24 is formed in the base metal part 12 for the chip saw B formed flat.
In the tip saw A in which a to 24j (26a to 26j) are formed, the circumferential grooves 24a to 24j (26a to 26j) are used.
It has been found that the frictional heat is suppressed low by the heat radiation effect caused by the above.

Next, the rotational speed of the rotary drive source is set to 2400 r.
An experiment was conducted to detect the temperature distribution of frictional heat along the radial direction of the tip saws A and B in the state where the setting was set to pm. In addition, as a method of generating frictional heat, a method of pressing a piece of wood against one side surface of the chip saw A (B) as in the above experiment was adopted.

FIGS. 10 and 11 show the results of this experiment. FIG. 10 shows the temperature distribution of the chip saw A, and FIG. 11 shows the temperature distribution of the chip saw B. The characteristic curves in FIGS.
4 seconds (characteristic curve), 8 seconds (characteristic curve), 12 seconds (characteristic curve), 16 seconds (characteristic curve), 20 seconds ( Characteristic curve), after 24 seconds (characteristic curve) and 2
The temperature distribution after a lapse of 8 seconds (characteristic curve) is shown along the radial direction of the tip saw A (B). Note that the range surrounded by the dashed line in FIGS. 10 and 11 indicates a friction portion where the piece of wood contacts the tip saw A (B).

As can be understood from FIGS. 10 and 11, it was found that the temperature rise of the chip saw A due to frictional heat was suppressed as compared with the chip saw B. For example, in FIG. 10 and FIG. 11, when comparing the characteristic curves after the friction time of 28 seconds has elapsed, the temperature caused by the frictional heat is about 30 ° C. in the tip saw A, whereas the temperature in the tip saw B is about 30 ° C. It was found that the temperature had risen to 47 ° C.

From the above experimental results, the chip saw A in which the circumferential grooves 24a to 24j (26a to 26j) are formed in the base metal part 12 is smaller than the chip saw B in which the base metal part 12 is formed flat. It was confirmed that the frictional heat generated at the time was appropriately radiated.

Next, a tip saw 10a (hereinafter referred to as tip saw C) according to a modification of the present embodiment and a circumferential groove 24a
A friction test similar to that described above was performed using the tip saw B in which both the front and back surfaces of the base metal part 12 were flat without having to 24j (26a to 26j).

The difference from the above-described experiment is that the tip saw C according to the modification has a plurality of circumferential grooves 24 having a triangular cross section.
a to 24j (26a to 26j) and the circumferential groove 2
The depth of 4a to 24j (26a to 26j) is H (mm),
The interval between adjacent circumferential grooves is defined as R (mm) (see FIG. 13), and an experiment was performed using tip saws C having different depths H and different intervals R of the circumferential grooves 24a to 24j (26a to 26j). went.

FIGS. 14A and 14B show the frictional state in the elapsed time of friction for 30 seconds after pressing a piece of wood against the chip saw B using the chip saw B having both the front and back surfaces of the base 12 flat. I have. In this case, FIG.
A is the pushing force P (kgf) and the friction force F in FIG.
2 shows a friction coefficient (F / P) obtained based on (kgf).

Subsequently, FIGS. 15A and 15B to FIG.
FIG. 19A and FIG. 19B show a frictional state in the elapsed time of 30 seconds of friction after pressing a piece of wood against the tip saw C using the tip saw C according to the modification. In this case, FIGS. 15A to 19A show the friction coefficient (F / P) obtained based on the pushing force P (kgf) and the friction force F (kgf) in FIGS. 15B to 19B.

15A and 15B show that the depth of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C is H = 0.2 mm, and the distance between adjacent circumferential grooves is R = R.
16A and FIG. 16B, the depth of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C is H = 0.4 mm, and the distance between adjacent circumferential grooves is R =
17A and FIG. 17B show that the depth of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C is H = 0.6 mm, and the distance between adjacent circumferential grooves is R =
18A and FIG. 18B show that the depth of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C is H = 0.8 mm, and the interval between adjacent circumferential grooves is R =
19A and FIG. 19B, the depth of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C is H = 1.0 mm, and the interval between adjacent circumferential grooves is R =
It is set to 0.2 mm.

Next, FIG. 20A and FIG.
A and the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C shown in FIGS. 15B to 19A and 19B.
10 shows the relationship between the friction coefficient (F / P) and the temperature rise (° C.) when the depth H of j) is changed. In FIG. 20B, the line connecting the circles is the characteristic curve of the indentation force P, the line connecting the triangles is the characteristic curve of the coefficient of friction (F / P), and the line connecting the squares is the frictional force. The characteristic curve of F is shown.

As can be understood from FIG. 20A, the temperature rise is reduced by increasing the depth H of the circumferential grooves 24a to 24j (26a to 26j) of the tip saw C to increase the contact area with air. It was found that the frictional heat was appropriately radiated.

[0036]

As described above, according to the present invention, a concave portion is provided in a base portion constituting a rotary cutting tool, thereby increasing the contact area of the base portion with air. The area where air contacts the base metal part increases,
A heat radiation action is performed through the recess.

As a result, it is possible to eliminate the risk of thermal expansion that may occur in the base portion or the cutting blade portion.
Therefore, it has excellent cutting ability, high accuracy, and
A rotary cutting tool having high durability and no generation of abnormal noise can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a tip saw according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of the tip saw shown in FIG.

FIG. 3 is a partial cross-sectional view showing a modification of a circumferential groove.

FIG. 4 is a partial cross-sectional view showing a modification of the circumferential groove.

FIG. 5 is a partial cross-sectional view showing a modification of the circumferential groove.

6 is a perspective view of a state in which a piece of wood is pressed against the tip saw A shown in FIG. 1 to detect frictional heat.

FIG. 7 is a perspective view of a state where a piece of wood is pressed against a tip saw B according to a comparative example to detect frictional heat.

8A to 8D are explanatory views showing thermal images of the tip saw A shown in FIG. 1 and a tip saw B according to a comparative example.

9 and FIG. 6 show a chip saw A (B).
It is explanatory drawing which shows the pressing state of the wood piece with respect to.

FIG. 10 is a temperature distribution characteristic diagram of the tip saw A in the radial direction due to frictional heat.

FIG. 11 is a temperature distribution characteristic diagram of the tip saw B in the radial direction due to frictional heat.

FIG. 12 is a plan view showing a modification of the tip saw shown in FIG. 1, in which a circumferential groove is formed over substantially the entire surface of a base.

FIG. 13 is a cross-sectional view of a tip saw C according to another modification.

FIG. 14A is a characteristic diagram showing a relationship between a friction coefficient and a friction elapsed time when a tip saw B is used, and FIG. 14B.
FIG. 6 is a characteristic diagram showing a relationship between a pushing force, a frictional force, and a frictional elapsed time when a tip saw B is used.

FIG. 15A shows a tip saw C (H = 0.2, R
= 1.8) is a characteristic diagram showing the relationship between the friction coefficient and the elapsed friction time when using the tip saw C. FIG. 15B shows the relationship between the pushing force, the friction force and the elapsed friction time when the tip saw C is used. It is a characteristic diagram.

FIG. 16A and FIG. 16B are characteristic diagrams when H = 0.4 and R = 1.4 in tip saw C;

17A and 17B are characteristic diagrams when H = 0.6 and R = 1.0 in the tip saw C;

FIG. 18A and FIG. 18B are characteristic diagrams when H = 0.8 and R = 0.6 in tip saw C;

19A and 19B are characteristic diagrams when H = 1.0 and R = 0.2 are set in the tip saw C. FIG.

FIG. 20A shows a depth H of a circumferential groove of a tip saw C;
FIG. 20B is a characteristic diagram showing the relationship between the depth H of the circumferential groove of the tip saw C and the friction coefficient.

[Explanation of symbols]

10, 10a: tip saw 12: base metal part 14: cutting blade part 16 ... bulging part 18 ... tip 20 ... central hole 22a to 22j ... slit 24, 24a to 24j, 26a to 26j, 32a to 32
j, 34a to 34j: circumferential groove 28a to 28j, 30a to 30j: dovetail groove

Claims (6)

[Claims] 1. A base metal part having a disc shape, and a cutting blade part having a plurality of cutting blades continuously formed on a peripheral part of the base metal part, wherein a center part of the base metal part is provided. A center hole that is axially attached to a rotation shaft of a rotation drive source; and the base metal portion is provided with a plurality of recesses at an intermediate portion between the center hole and the cutting blade portion. Cutting tools. 2. A rotary cutting tool according to claim 1, wherein the plurality of recesses are provided over substantially the entire surface of an intermediate portion between the center hole and the cutting edge portion, or at a predetermined portion. tool. 3. The rotary cutting tool according to claim 1, wherein the plurality of recesses are provided on both front and back surfaces of the base. 4. The rotary cutting tool according to claim 1, wherein the concave portion comprises a plurality of concentric circumferential grooves. 5. The rotary cutting tool according to claim 4, wherein the circumferential groove formed on the front surface of the base metal portion and the circumferential groove formed on the back surface have different diameters. And rotary cutting tools. 6. The rotary cutting tool according to claim 4, wherein the cross-sectional shape of the circumferential groove is at least one of a dovetail shape, a semicircle shape, a triangular shape, and a square shape. Rotary cutting tool.