JP2001062638A - Induction heating type shrinkage fitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform rapid and automatic heating and cooling treatment of a tool holder, to reduce the size of a device, and to be decreased in a price. SOLUTION: This shrinkage fitting device is operated such that a coil is charged with an AC current, a tool holder 2 is heated by an induction current, and the shank part of a cutter 3 is securely shrinkage-fitted in its hole part. In this case, the coil consists of a pair coils 1a and 1b, a pair of the coils 1a and 1b are situated at the side of the tool holder 2. The shank part of the cutter 3 is heated in a way the coil is charged with a current such that a magnetic flux generated by the two coils 1a and 1b is always generated in the same direction. The temperature of the part, heated by the coil, of the tool holder 2 is detected by a temperature detecting means 14. When the detecting temperature reaches a temperature higher than a given temperature, heating of the coil is automatically stopped, and the tool holder is cooled by supply of air. When temperature detected by the temperature detecting means is decreased to a value lower than a given temperature, air supply through an air supply nozzle is automatically stopped.

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 the 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. 5, 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. 5, since the tool holder 2 itself to be heated self-heats due to eddy current loss, the 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.

When the tool holder 2 with the blade 3 mounted thereon and shrink fit completed is 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 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.

Further, in order to shorten the shrink fitting time as much as possible, the temperature of the tool holder 2 is monitored during the shrink fitting.
When the temperature reaches the shrink-fittable temperature, it is necessary to prompt the user to insert the blade 3 with a lamp, voice, or the like, and to stop heating. However, in the induction heating method, since the heating portion of the tool holder 2 is surrounded by the coil 1, the coil 1 is an obstacle, and the temperature of the heating portion cannot be directly measured by a thermocouple or the like. Therefore, the temperature of the portion without the coil 1 is measured and the temperature of the heated portion is indirectly estimated.
This method has a problem that the temperature is inaccurate, and at the same time, it takes time to conduct heat to the temperature measurement portion, and the heating time becomes long.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a coil comprising a pair of coils wound around a cylindrical or prismatic core, and positioning the coil on a side surface of a tool holder. The arrangement is adjustable so 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 attachment and detachment of the tool holder from the shrink fitting device can be easily performed by moving the coil position.

Further, by detecting the temperature near the portion of the tool holder heated by the coil by the temperature detecting means, the heating of the coil is performed when the temperature detected by the temperature detecting means reaches a predetermined temperature or higher. The cooling can be automatically stopped, and when the tool holder is cooled, the cooling can be automatically stopped when the temperature detected by the temperature detecting means falls below a predetermined temperature.

[0015]

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 type shrink fitting device, the coil is constituted by a pair of coils wound around a cylindrical or prismatic core, and the coil is arranged on a side surface of the tool holder so as to be adjustable in position, and the coil of the tool holder is The temperature in the vicinity of the portion to be heated is detected by temperature detecting means, and when the temperature detected by the temperature detecting means reaches a predetermined temperature or higher, the heating is automatically stopped. is there.

According to a second aspect of the present invention, an air blowing nozzle is provided near the tool holder, and the heated tool holder is cooled by blowing air from the air blowing nozzle, so that the temperature detected by the temperature detecting means becomes lower than a predetermined temperature. At this time, the blowing from the blowing nozzle is automatically stopped.

[0017]

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 device of the present invention. The shrink-fitting device main body 9 includes an operation unit 10 and a control unit 18 inside, and a tool holder support unit 11 and a coil position on the top. An adjusting unit 12 is provided. The operation unit 10 includes a heating start switch 13, a heating completion lamp 15, and a cooling button 16.
And a pair of coils 1 positioned so as to face the side surface of the tool holder 2 in the coil position adjusting unit 12.
a, 1b, a holding portion 8 for holding the coils 1a, 1b movably in the lateral direction, an operation knob 17, and temperature detecting means 14. The temperature detecting means 14 detects the temperature of the tool holder 2.

FIG. 2 shows a detection window as the temperature detecting means 14 for detecting infrared rays by detecting infrared rays in a non-contact manner. The detecting means such as a thermocouple, a thermistor, etc. is pressed against the tool holder 2 by a spring. The temperature may be detected by a contact method.

FIGS. 3 and 4 show an example of a structure for cooling the tool holder 2 after the completion of heating by the coils 1a and 1b, respectively. FIG. 3 shows that a solenoid valve 20 is supplied from a compressor 19 installed outside. The front end of a blower nozzle 21 for sending cool air to the hole 2a of the tool holder 2 through the tool is facing. The electromagnetic valve 20 is automatically opened and closed by a control unit 18 connected to the temperature detecting means 14.

FIG. 4 shows a blower nozzle 21 connected to the tip of a cooling fan 22, and the tip of the blower nozzle 21 faces the hole 2 a of the tool holder 2. The cooling fan 19 is automatically opened and closed by a control unit 18 connected to the temperature detecting means 14.

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

When shrink-fitting the blade 3 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 (typically 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.

The magnetic flux 7 generated by the 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 and automatically stops energization of the coils 1a and 1b. The heating completion lamp 15 is turned on, and a buzzer (not shown) is sounded to notify the user of the completion of heating.

At this time, since the temperature detecting means 14 measures the temperature in the vicinity of the tool holder 2 in a non-contact manner by infrared rays, a mechanism for pressing the temperature detecting means 14 against the tool holder 2 becomes unnecessary, and the mechanism is simplified. In addition, accurate temperature measurement can be performed without being affected by dirt on the surface of the tool holder.

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, cooling air is blown toward the tool holder 2 and the tool holder 2
To cool. This cooling method uses cooling air sent from an external compressor 19 as shown in FIG.
0 may be blown to the tool holder 2 from the tip of the blower nozzle 21, and as shown in FIG.
May be blown to the tool holder 2 from the tip of the blow nozzle 21.

By this cooling, the hole portion 2a of the tool holder 2 which has been thermally expanded contracts and tightens the blade 3, so that it does not come off. Thereafter, when the temperature drops to a safe level even if the hole 2a of the tool holder 2 is touched, the temperature detection means 14 detects the temperature and the blowing from the blowing nozzle 21 automatically stops.

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 has been completed can be removed from the shrink fitting device.

Next, when the blade 3 is removed from the tool holder 2 already shrink-fitted, the same procedure as described above may be performed. 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.

[0033]

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 is 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 the optimum heating efficiency. The coil can be moved to the position where it is set. 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 attachment and detachment of the tool holder is facilitated.

Further, by detecting the temperature near the heating portion of the tool holder by the temperature detecting means, it is accurately detected that the temperature required for shrink fitting has been reached, and the heating of the coil is automatically stopped. Further, also at the time of cooling, it is possible to accurately detect that the temperature has dropped to a temperature that can be touched by the user and automatically stop the cooling by the blowing nozzle. As a result, the operation time can be shortened.

[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 an explanatory view of an air blowing structure according to one embodiment of the present invention.

FIG. 4 is an explanatory view of a blowing structure according to another embodiment of the present invention.

FIG. 5 is a heating principle diagram of a conventional shrink fit device.

[Explanation of symbols]

 Reference Signs List 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 14 Temperature Detection Means 18 Control Unit 21 Blowing Nozzle

Claims (2)

[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).
In the induction heating shrink-fitting device for fixing a) by shrink fitting, the coil (1) is constituted by a pair of coils (1a) and (1b) wound around a cylindrical or prismatic core. 1a) and (1b) are arranged on the side surface of the tool holder (2) so as to be position-adjustable, and the temperature in the vicinity of the portion of the tool holder (2) heated by the coils (1a) (1b) is detected by temperature detecting means ( 14), and when the temperature detected by the temperature detecting means (14) reaches a predetermined temperature or higher, the coils (1a) (1)
An induction heating shrink fit apparatus wherein the heating according to b) is automatically stopped. 2. An air blowing nozzle (21) is provided near the tool holder (2), and the heated tool holder (2) is cooled by blowing air from the air blowing nozzle (21). 2. An induction-heating shrink-fitting device according to claim 1, wherein when the temperature to be detected falls below a predetermined temperature, the blowing from the blowing nozzle (21) is automatically stopped.