JP2001018127A - Induction heating shrinkage fitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To complete a heating treatment of a tool holder in a short time, in a shrinkage fitting device having a shank part of cutter fitted on a hole part of the tool holder with shrinkage fitting by induction heating, and to provide the device itself at a low cost. SOLUTION: In an induction heating shrinkage fitting device having a coil 1 charged with an alternating current for heating a tool holder 2 by an induction current generated thereby to fix a shank part 3a of a cutter 3 to its hole part 2a by shrinkage fitting, the coil 1 is formed with a pair of coils 1a and 1b coiled on a cylindrical or prismatic core for having the pair of coils 1a and 1b arranged justifiably opposite a side face of the tool holder 2 to charge the coils 1a and 1b with the current such that magnetic flux generated by the coils 1a and 1b is always kept in the same direction for heating the shank part 3a of the cutter 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating shrink fitting apparatus for fixing a shank portion of a blade to a hole of a tool holder by shrink fitting by induction heating.

[0002]

2. Description of the Related Art In general, as a method of fitting a metal shaft member into a hole of a metal holder or the like, a shrink-fitting method utilizing a difference in coefficient of thermal expansion of a metal is widely used.

In the field of metal working, various shrink-fitting devices have been developed for attaching and detaching blades to and from a tool holder connected to a main shaft of a machine tool.

As shown in FIG. 3, a tool holder 2 is inserted into a coil 1 and heat is generated by an eddy current loss caused by an induced current generated by a change in magnetic flux. The tool holder 2 is heated using an induction heating type in which the shank portion 3a of the blade 3 is fixed to the hole 2a, a burner type in which the flame of combustible gas is used as a heat source, or hot air generated by blowing air to a heating wire as a heat source. There is a heater type that performs the following. (For example, Published Patent Application 8-502
No. 212, JP-A-11-77443)

[0005]

However, in the burner type and the hot air type, since a tool holder is heated from the outside, a considerable amount of heat escapes into the air, and there is a problem that energy efficiency is very poor. Was. Further, since the tool holder is heated from the outside and the inside is heated by heat conduction, there is a problem that it takes time to heat the tool holder to a temperature required for shrink fitting.

On the other hand, in the induction heating type shown in FIG. 3, since the tool holder 2 itself to be heated generates heat by eddy current loss, energy efficiency is high, and the inside and outside of the tool holder 2 generate heat simultaneously. Therefore, there is an effect that heating is completed in a short time.

However, in order to effectively transmit the magnetic flux generated from the coil 1 to the tool holder 2, it is necessary to form a coil having an optimal shape according to the shape of the tool holder 2.

For this reason, when shrink-fitting, it is necessary to select and replace an optimum coil 1 corresponding to tool holders 2 of various sizes, and there has been a problem that setup takes time.

Further, there is a problem that various coils are required and the apparatus becomes expensive.

Further, when the tool holder 2 on which the blade 3 is mounted and shrink-fitting is completed is to be removed from the apparatus, the tool holder 2 is removed unless the coil 1 is moved from the positions of the tool holder 2 and the blade 3 as shown by arrows. Therefore, a slide mechanism for moving the coil 1 was required. Since the moving length of the slide mechanism needs to be longer than the length of the tool holder 2 and the blade 3, there is a problem that the apparatus becomes large.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a pair of coils wound around a cylindrical or prismatic core, and the position of the coils is adjusted on the side of a tool holder. The arrangement is such that even if the dimensions of the tool holder differ, the position of the coil can be adjusted to heat the tool holder.

At the start and at the completion of the shrink fit, the tool holder can be easily attached to and detached from the shrink fitting device by moving the coil position.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, an alternating current is applied to a coil, the tool holder is heated by an induced current generated by the alternating current, and a shank portion of a cutting tool is fixed in a hole of the tool holder by shrink fitting. In the heating shrink fitting apparatus, the coil is constituted by a pair of coils wound around a cylindrical or prismatic core.

According to a second aspect of the present invention, a pair of coils are disposed so as to face the side surface of the tool holder, and current is supplied to the coils so that magnetic fluxes generated by the two coils are always in the same direction.

According to a third aspect of the present invention, the pair of coils are arranged on the side surface of the tool holder so as to be adjustable in position.

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing the principle of the present invention. In the drawing, reference numerals 1a and 1b denote a pair of coils, which are wound around a core 4 made of a columnar or prismatic ferrite material through a bobbin 5. 6 is wound. Reference numeral 2 denotes a tool holder, 2a denotes a hole thereof, 3 denotes a blade, and 7 denotes a direction of a magnetic flux generated inside and around the coils 1a and 1b during heating.

FIG. 2 is an external view of the shrink fitting apparatus according to the present invention. The shrink fitting apparatus main body 9 has an operation unit 10 and a control unit (not shown) inside, and a tool holder support unit on the upper part. 11
And a coil position adjusting unit 12. The operation unit 10 is provided with a heating start switch 13, a heating completion lamp 15, and a cooling button 16. The coil position adjusting unit 12 includes a pair of coils 1a and 1b positioned so as to face the side surface of the tool holder 2. A holding portion 8 for holding the coils 1a and 1b movably in the lateral direction, an operation knob 17 and a temperature detecting means 14. The temperature detecting means 14 detects the temperature of the tool holder 2.

In FIG. 2, a detection window for detecting infrared rays and detecting the temperature without contact is shown as the temperature detection means 14, but the detection means such as a thermocouple or thermistor is pressed against the tool holder 2 by a spring. Alternatively, the temperature may be detected by a contact method.

Next, the operation of the present invention will be described.

When the cutting tool 3 is shrink-fitted into the tool holder 2, first, the tool holder supporting portion 11 of the shrink-fitting device main body 9 is used.
The tool holder 2 is set in the
By operating the operation knob 17 at 2, the height of the coils 1a and 1b and the distance h between the tool holder 2 and the coils 1a and 1b are adjusted to be optimum.

Next, when the heating start switch 13 of the operation unit 10 is pressed, a high-frequency current (normally 20 k) is applied to the coils 1a and 1b.
Hz or more). The direction of the high-frequency current flowing through the coils 1a and 1b is the same as that of the magnetic flux 7 in FIG.
Flow in such a manner that a magnetic flux is generated in the same direction. The direction of the magnetic flux 7 in FIG. 1 represents a moment, and in fact, the direction of the magnetic flux 7 also changes in synchronization with the high-frequency current flowing through the coils 1a and 1b.

Magnetic flux 7 generated by both coils 1a and 1b
Penetrates the inside of the tool holder 2. At this time, an induced current induced by the magnetic flux flows through the magnetic flux penetrating portion of the tool holder 2, and the eddy current loss generated thereby causes the tool holder 2.
Generates heat. The tool holder 2 thermally expands due to this heat generation,
The hole diameter of the hole 2a increases.

When the temperature of the tool holder 2 reaches a temperature sufficient for shrink fitting, the temperature detecting means 14 detects this temperature, the heating completion lamp 15 of the operation section 10 is turned on, and a buzzer (not shown) is turned on. Sounds to notify the user of the completion of heating.

The user inserts the cutting tool 3 into the hole 2a of the tool holder 2.
Insert After the insertion, when the user presses the cooling button 16, air is blown toward the tool holder 2 to cool the tool holder 2. Although the cooling structure is not shown here, there are a method of opening and closing air from an external compressor with a valve to blow air to the tool holder 2 and a method of blowing air with a fan. Tool holder 2 thermally expanded by cooling
The hole 2a is shrunk and tightens the blade 3 so that it does not come off.

After cooling, by moving the coils 1a and 1b of the coil position adjusting unit 12 away from the tool holder 2, the tool holder 2 whose shrink fit is completed can be removed from the shrink fitting device.

Next, when removing the blade 3 from the tool holder 2 already shrink-fitted, the same procedure as described above may be used. First, the tool holder 2 with the blade 3 is set, and the positions of the coils 1a and 1b are adjusted, and then heating is started. When the heating is completed, the blade 3 is removed and cooled. After cooling, the coils 1a and 1b are moved away from the tool holder 2, and the tool holder 2 is removed from the shrink fit device, and the operation is completed.

[0028]

As described above, according to the present invention, since the tool holder is caused to generate heat from the inside by induction heating, the heat efficiency is good and the heat treatment is completed in a short time.

Further, since the pair of coils are arranged on both side surfaces of the tool holder so as to be adjustable, even if the dimensions of the tool holder change, the positions of the coils can be easily changed to obtain an optimum heating efficiency. The coil can be moved to the position where Therefore, it is not necessary to replace the coil every time the dimensions of the tool holder change, and the setup time can be reduced.

Further, since only one kind of coil is required, there is an effect that the apparatus can be provided at a low price.

Further, the coil can be separated to a position where it does not hinder the attachment / detachment of the tool holder by a position adjusting mechanism of a small distance about the outer diameter of the tool holder. This has the effect that the holder can be easily attached and detached.

[Brief description of the drawings]

FIG. 1 is a heating principle diagram of an embodiment of the present invention.

FIG. 2 is an external perspective view of one embodiment of the present invention.

FIG. 3 is a heating principle diagram of a conventional shrink fit device.

[Explanation of symbols]

 1a Coil 1b Coil 2 Tool Holder 3 Cutting Tool 9 Shrink Fitting Device Main Body 10 Operation Unit 12 Coil Position Adjustment Unit 13 Heating Switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K059 AA09 AB00 AB10 AB14 AB22 AC07 AC10 AC33 AC35 AC37 AC42 AC72 AD03 AD07 AD15 AD32 AD35 AD40 BD02 CD14 CD72

Claims (3)

[Claims] 1. An alternating current is passed through a coil (1), and the induced current generated thereby heats a tool holder (2). A shank (3) of a cutting tool (3) is inserted into a hole (2a).
(a) An induction heating shrink-fitting device in which a) is fixed by shrink fitting, wherein the coil (1) is constituted by a pair of coils (1a) and (1b) wound around a cylindrical or prismatic core. Induction heating type shrink fit equipment. 2. A pair of coils (1a) and (1b) are arranged opposite to a side surface of a tool holder (2), and both coils (1a) and (1b) are arranged.
2. The induction-heating shrink-fitting device according to claim 1, wherein a current is applied to the coils (1a) and (1b) so that the magnetic flux generated by a) and (1b) is always in the same direction. 3. An induction heating shrink fitting device according to claim 1, wherein the pair of coils (1a) and (1b) are arranged on the side surface of the tool holder (2) so as to be adjustable.