JPH1192828A - Heat treatment of saw and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment method which imparts a stress on a saw in place of tensioning and an apparatus therefor. SOLUTION: The circular saw 3 is mounted at the revolving shaft 2 of a motor 1. Cooling water is put into a cooling water tank 10 in such a manner that the part from the outer periphery of the circular saw to about its center is soaked into the cooling water. A piston is moved in a circular saw direction by an air cylinder, by which a second pedestal is moved toward the circular saw 3 and a guide roller is pressed on the surface of the circular saw 3. A motor power source 11 is operated and the saw 3 is rotated through the revolving shaft 2. A high-frequency oscillator 8 is operated as well to pass high-frequency currents to the coils in coil bodies 4, 5, by which the parts of the saw countering the respective coils are subjected to high-frequency induction heating. The saw is immersed into the cooling water in the cooling water tank and is rapidly cooled right after the heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saw heat treatment method and apparatus for imparting thermal stress to a saw.

[0002]

2. Description of the Related Art In the manufacturing process of saws for cutting lumber and the like, there is a need for a process that greatly affects the quality of saws. With this squatting, when sawing wood or the like with a saw, cracks occur in the saw due to deformation due to frictional resistance, or when cutting the timber etc. by rotating the saw at high speed, the flatness of the saw can not be maintained, As a result, this is performed in order to suppress the phenomenon that the cut surface of the timber or the like becomes rough, and is a step of partially applying stress to the saw.

[0003] The manufacture of saws involves an annealing step (eg, 73
Heating to 0 ° C. to 760 ° C., gradually cooling to remove internal strain), roughing step of the tooth portion, quenching step (for example,
Heated to 760 ° C to 820 ° C, quenched and cured),
The tempering process (heated to 150 ° C. to 200 ° C., and naturally cooled in air to increase toughness and reduce hardness and internal strain), and the finish polishing process of the teeth are performed in this order. Is performed between the tempering step and the finish polishing step of the tooth portion.

[0004]

[0005] Such squatting is performed by a craftsman applying an impact to both sides of the saw with a hammer or the like. However, even for a craftsman, not only the quality after squatting occurs due to the artificial work, but also the squatting work itself is extremely troublesome work.

[0005] The present invention has been made in view of the above problems, and has as its object to provide a novel heat treatment method and apparatus for applying stress to a saw instead of the conventional stiffening.

According to the heat treatment method for a saw according to the invention of claim 1, after performing high-frequency induction heating in a band shape on the inner side of the saw teeth at a constant interval with respect to the arrangement of the saw teeth, It is characterized by rapid cooling.

The heat treatment method for a saw according to the second aspect of the present invention is characterized in that high-frequency induction heating is performed in a band shape between the outer circumference of the saw and approximately 2/3 of the center or the bottom of the teeth as viewed from the outer circumference of the saw. And The heat treatment method for a saw based on the invention according to claim 3 is characterized in that high-frequency induction heating is performed on a band having a width of about 1/70 to 1/600 of the diameter of the saw.

The heat treatment method for a saw according to the invention of claim 4 is characterized in that it is rapidly cooled by water cooling. A heat treatment method for a saw based on the invention according to claim 5 is characterized in that a plurality of bands are subjected to high-frequency induction heating at a predetermined interval. The heat treatment apparatus for a saw based on the invention according to claim 6 is a high-frequency induction heating coil arranged so as to oppose both sides of the saw in a direction perpendicular to the saw surface, and bringing both the high-frequency induction heating coils closer to the saw. Means, a moving mechanism for moving the saw so that the high-frequency induction heating coil performs high-frequency induction heating in a band shape at a constant interval with respect to the arrangement of the saw teeth, and for cooling the saw immediately after heating by the high-frequency induction heating coil It is characterized by having a cooling means.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an example of a saw heat treatment apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes a motor, and a circular saw 3 is attached to a rotating shaft 2 of the motor. Reference numerals 4 and 5 denote coil bodies arranged near both sides of the circular saw, and reference numerals 6 and 7 denote moving mechanisms for moving the coil bodies in a direction perpendicular to the plane of the circular saw. 8
Is a high-frequency oscillator, and 9 is a matching device for matching the impedance on the load side with the impedance on the oscillator side. Numeral 10 denotes a cooling water tank which contains cooling water enough to immerse a part of the saw 3. 11 is a power supply for the motor, 12 is a radiation thermometer, and 13 is a control device. The control device appropriately controls the output of the high-frequency oscillator 8 based on the temperature measured by the thermometer.

The coil units 4 and 5 and the moving mechanisms 6 and 7 will be described below in detail with reference to FIGS. For convenience of explanation, one of the coil bodies 4 and the moving mechanism 6
However, the other coil body 5 and moving mechanism 7 have the same configuration.

As shown in FIG. 2, the coil bodies 4 and 5 are mounted on first pedestals 14 and 15, respectively. As shown in FIGS. 4A and 4B, the coil body has a core (for example, a dust core) 17 mounted inside an inflection portion in a box 16 made of an insulating material (for example, epoxy). A copper pipe-shaped coil 18 is sealed. That is, a hole 19 is formed in the heat-treated member side of the box 16, and the coil 18 is accommodated in the hole so that the outside portion of the inflection portion of the coil protrudes. It is taken out through a hole in the upper surface. When attaching the core 17 to the inflection portion of the coil 18, as shown in FIG.
A hollow semi-cylindrical core 17 is attached so as to straddle the coil inflection portion. Both ends of the coil taken out are shown in FIG.
As shown in (1), it passes through the first pedestal 14 and is taken out above the pedestal. As shown in FIG. 2, one of the two terminals of the coil is a strip-shaped copper plate 2 connected to lead plates 20 and 21 connected to the output terminal of the matching box 9 respectively.
2 and 23, and the other is connected to a common strip-shaped copper plate 24, respectively. Although not shown, cooling water is introduced from one terminal of the coil and discharged from the other terminal. Holes for introducing and discharging cooling water for cooling the core 17 are formed in one side surface of the box 16, and introduction and discharge pipes 25 and 26 are provided in the respective holes. ing. Therefore, since the inside of the box is filled with cooling water, all the holes opened in the box are waterproofed with silicon or the like.

On the upper surfaces of the first pedestals 14 and 15 on which the coil bodies 4 and 5 are mounted, the tips of the first pedestals 14 and 15 are slightly opposite to the inflection portions of the coils 4 and 5 (to be heat-treated). Guide rollers 29, 3 made of an insulating member via support plates 27, 28 (28 not shown) so as to come out to the side of the member.
0 (30 is not shown) is attached. Terminals on one side of shafts 31, 32, 33, 34 are fixed to a surface opposite to the surface on which the coil bodies 4, 5 are mounted, and the other side of each shaft is a second terminal. Pedestal 3
It is inserted into the through-holes opened in 5, 36. Therefore, the second pedestals 35, 36 are provided with shafts 31, 32, 33,
It is possible to move along. Springs 37, 38 (38 not shown) are provided on the opposing surfaces of the first and second pedestals.
Is attached. The second pedestal has an air cylinder 3
Pistons 41 and 42 that reciprocate are connected by 9 and 40. With such a structure, the air cylinder 3
When the pistons 41 and 42 move toward the member to be heat-treated by the components 9 and 40, the second pedestals 35 and 36 try to approach the first pedestals 14 and 15, so that the elastic force of the springs 37 and 38 (38 not shown). The first pedestals 14 and 15 move toward the member to be heat-treated. On the other hand, when the pistons 41, 42 move in the opposite directions by the air cylinders 39, 40, on the contrary, the second pedestals 35, 36 tend to move away from the first pedestals 14, 15, so the springs 37, 38 (38 are shown in the drawing). Z)
The first pedestals 14 and 15 move in the opposite direction to the member to be heat-treated, following the elastic force of the first member.

As shown in FIG. 2, the second pedestals 35, 36 are attached to one ends of support rods 43, 44, and the other ends of the support rods have the matching device 9 inside. Are mounted on bearings 46 and 47 provided in a matching box 45 provided in the above. With this structure, the second pedestal is supported by the support rods 43 and 44, and at the same time, the bearing 4
The rotation of the pistons 6 and 47 enables the pistons 41 and 42 to move in the moving direction. In FIG. 2, an insulating member 48 is inserted between the lead plates 20 and 21.

A method for applying a thermal stress to the circular saw after the tempering process using the saw heat treatment apparatus having such a structure will be described below.

First, the circular saw 3 is mounted on the rotating shaft 2 of the motor 1 as shown in FIG. At this time, the coil bodies 4 and 5 are arranged at a certain distance from the circular saw surface so as to be opposed from both sides near the center between the outer periphery and the center of the circular saw. Further, cooling water is poured into the cooling water tank 10 so that a portion of the circular saw from the outer periphery to the center is immersed in the cooling water.

In this state, the pistons 41, 42 are moved in the circular saw direction by the air cylinders 39, 40, whereby the second pedestals 35, 36 are moved in the circular saw direction based on the rotation of the bearings 46, 47. By this movement, the rollers hit the surface of the circular saw 3 with the guide rollers 29 and 30 (30 is not shown). Here, the motor power supply 11 operates according to a command from the control device 13, and the saw 3 rotates through the rotating shaft 2.
At the same time, the high-frequency oscillator 8 also operates according to a command from the control device 13, and a high-frequency current flows to the coils in the coil bodies 4 and 5 through the matching device 9. Then, the coil in the coil body heats a high frequency induction heating of a saw portion opposing each coil. At this time, the heating depth is largely determined by the output frequency of the high-frequency oscillator, and the heating width is determined by the diameter of the coil. However, the heating width can be increased to some extent by increasing the heating time. By such heating, the middle part of the outer circumference of the tooth from the center of the saw is parallel to the outer circumference,
Induction heating is performed in a strip shape having a width substantially corresponding to the diameter of the coil. At this time, the temperature of the heated portion is detected by the radiation thermometer 12, and a temperature signal is constantly sent to the control device 13 so as to be heated at a predetermined temperature. The control device sends a command to the high-frequency oscillator 8 based on the temperature of the heating portion,
The high frequency output is controlled (of course, the higher the output, the higher the heating temperature). The saw-shaped induction-heated saw is immersed in the cooling water of the cooling water tank 10 immediately after the heating, and rapidly cooled. In this manner, the belt is induction-heated and rapidly cooled, so that the band-like portion of the saw can have thermal stress.

For example, as an example, a circular saw having a diameter of 400 mm and a thickness of 2.5 mm is rotated at a speed of 30 mm / sec.
The output of the high-frequency oscillator was set to 30 KW and 350 KHZ, and induction heating was performed at 400 ° C. to 450 ° C. with a coil having a diameter of 2 mm, whereby heating was possible in a band shape having a width of about 2 mm.

Now, when cutting wood or the like with a saw, the teeth of the saw may hit a hard part, or the saw may be cut, for example, 20 times.
If any impact is applied when cutting wood or the like by rotating at high speed at 00 rpm, a portion near the teeth including the saw teeth undulates like a wave, that is, a so-called blur phenomenon occurs, and it does not stop. Then, as in the present invention, when the saw is subjected to induction heating in a strip shape and rapidly cooled to give thermal stress in a strip shape in parallel to the outer periphery of the saw, the blur is absorbed by the strip portion. However, since the hardness of the portion to which the thermal stress is applied is lower than that before the application of the thermal stress, if the width of the band-shaped portion is wide, it cannot be sufficiently used as a saw. On the other hand, if the width of the belt-like portion is extremely narrow, the blur cannot be sufficiently absorbed. Therefore, it is effective that the width of the band-shaped portion for giving the thermal stress is about 1/70 to 1/600 of the diameter of the saw.
Therefore, as long as the total width does not exceed the width of this range, a thermal stress may be applied to two or more belt-shaped portions with as much space as possible.

Further, in the above embodiment, the intermediate portion of the outer periphery from the center of the saw is induction-heated and rapidly cooled to apply a thermal stress in a belt shape. The effect is greater near the teeth because it occurs in the vicinity of. The effect of this blur absorption is seen because the outer circumference and center of the saw are approximately 2/3 when viewed from the outer circumference of the tooth.
Up to However, if thermal stress is applied to the teeth,
Since the hardness of the tooth is reduced and it cannot be used as a saw, approximately 2/3 of the outer circumference and the center of the saw viewed from the tooth bottom to the outer circumference of the tooth.
It is effective to apply a thermal stress to the range.

In the above example, the heating temperature by the induction heating was 400 ° C. to 450 ° C., but was approximately 300 ° C. to 50 ° C.
0 ° C. is a suitable temperature.

In the above embodiment, the heat treatment of the circular saw has been described. However, it is needless to say that the heat treatment of the band saw can be applied.

In the above embodiment, since the coil is cooled by the cooling water for cooling the core, the coil is not formed in a pipe shape through which the cooling water can pass, but in a cylindrical or prismatic coil shape. May be used. In that case, a cooling water introduction / discharge mechanism for cooling the coil becomes unnecessary.

In the above embodiment, the guide rollers are mounted on the first pedestals. Instead, magnets are mounted on the first pedestals such that the same poles face each other, and the objects to be heated are repelled by the respective magnets. May be located in the middle of the coils provided on both sides.

[0025]

According to the present invention, a high-frequency induction heating is applied to the inside of the saw teeth at a constant interval with respect to the saw teeth arrangement and then rapidly cooled, so that the saw is parallel to the saw teeth arrangement. Since a thermal stress is applied to the part of the belt in a belt-like manner, the quality does not vary and the work is remarkably easy, unlike the conventional squatting work by craftsmen.

[Brief description of the drawings]

FIG. 1 shows an example of a heat treatment apparatus according to the present invention.

FIG. 2 shows a part of the heat treatment apparatus shown in FIG. 1 in detail.

FIG. 3 shows a part of the heat treatment apparatus shown in FIG. 1 in detail.

FIG. 4 shows a part of the heat treatment apparatus shown in FIG. 1 in detail.

FIG. 5 shows a part of the heat treatment apparatus shown in FIG. 1 in detail.

[Explanation of symbols]

1 ... motor, 2 ... rotary shaft, 3 ... saw, 4,5 ... coil body,
6, 7: moving mechanism, 8: high frequency oscillator, 9: matching device, 1
0 ... cooling water tank, 11 ... motor power supply, 12 ... radiation thermometer, 13 ... control device, 14, 15 ... first pedestal, 16 ...
Box, 18 ... coil, 19 ... hole, 20, 21 ... lead plate,
22, 23, 24: strip-shaped copper plate, 27: support plate, 29: guide roller, 31, 32, 33, 34: shaft, 3
5, 36 ... second pedestal, 37 ... spring, 39, 40 ...
Air cylinders, 41, 42 ... pistons, 43, 44 ... support rods, 45 ... matching box, 46, 47 ... bearings, 48
... Insulation members

Claims (6)

[Claims] 1. A saw heat treatment method in which a high frequency induction heating is applied in a band shape inside the saw teeth at a constant interval with respect to the saw teeth arrangement and then rapidly cooled. 2. The heat treatment method for a saw according to claim 1, wherein the high frequency induction heating is performed in a band shape between the outer circumference of the saw and approximately 2/3 of the center or the bottom of the teeth as viewed from the outer circumference of the saw. 3. The heat treatment method for a saw according to claim 1, wherein the high frequency induction heating is applied to a band having a width of about 1/70 to 1/600 of the diameter of the saw. 4. The method according to claim 1, wherein rapid cooling is performed by water cooling.
The method for heat treatment of a saw as described. 5. The saw heat treatment method according to claim 1, wherein high frequency induction heating is performed in a plurality of strips at a predetermined interval from each other. 6. A high frequency induction heating coil arranged to oppose both sides of the saw in a direction perpendicular to the saw surface,
Means for bringing both the high-frequency induction heating coils closer to the saw,
A moving mechanism for moving the saw so that the high-frequency induction heating coil performs high-frequency induction heating in a band-like manner at a predetermined interval with respect to the arrangement of the saw teeth, and a cooling unit for cooling the saw immediately after heating by the high-frequency induction heating coil Saw heat treatment equipment equipped with.