JPH0618480B2 - Slot-shaped insulating film forming device for squirrel cage rotor cores - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a slot insulating film forming apparatus for a squirrel cage rotor core, in which an insulating treatment liquid is adhered to an inner surface of a slot of the rotor core and baked.

[Technical background of the invention]

For example, a rotor of a squirrel-cage induction motor is manufactured by casting a secondary conductor by aluminum die casting into a slot of a squirrel-cage rotor core (hereinafter referred to as a rotor core). In this case, an insulating coating is formed on the inner surface of the slot prior to aluminum die casting to insulate the rotor core from the secondary conductor, which causes stray load loss and stray torque due to a short circuit between the secondary conductors. I try to prevent it. And, as a method of forming such an insulating coating, there has been the following method conventionally. That is, first, a cored bar is inserted into the shaft hole of the rotor core formed by stacking punched plates to hold the rotor core in a stacked state, and this is immersed in a solvent such as acetone to adhere to the punched plate. Remove oil (degreasing step). After that, the rotor core is immersed in an insulation treatment liquid to adhere the insulation treatment liquid to the surface of the rotor core including the inner surface of the slot (insulation treatment liquid adhesion step), and further, for example, the rotor core is placed in an electric furnace. The insulation treatment liquid stored and adhered was baked and solidified (baking process).

[Problems of background technology]

However, in the above method, since a solvent such as acetone is used in the degreasing step, it is difficult to remove harmful solvent vapors, and the residual solvent of this kind adversely affects the subsequent steps. Must be removed to
Therefore, there is a problem that an auxiliary process such as heating the rotor core after the degreasing process is required and the number of processes increases. In addition, in the insulating treatment liquid application step, there is a problem that the insulating treatment liquid permeates between the blanks and the shaft holes. If this happens, not only is the insulating processing liquid wasted wastefully, which is uneconomical, but the insulating processing liquid that has entered between the blanks reduces the space factor of the rotor core, increasing the magnetic resistance and increasing the motor resistance. Reduce the performance of. Further, since the insulation treatment liquid that has entered the shaft hole interferes with the press fitting of the rotary shaft into the shaft hole, an auxiliary step for removing the insulating coating on the inner surface of the shaft hole is required before the press fitting of the rotary shaft. Furthermore, in the baking process, although it is desirable to intensively heat only the inner surface of the slot to which the insulating treatment liquid adheres, the rotor core is housed in the electric furnace and indirectly heated from the outside. Because I try to heat
There is a problem in that unnecessary portions of energy are wasted by heating up to unnecessary portions, and therefore cooling after the baking step requires a long time and productivity cannot be improved.

[Object of the Invention]

The present invention has been made to eliminate the above-mentioned problems, and an object thereof is to reduce the number of steps as much as possible to improve the productivity, and also to improve the performance of a motor car. It is an object of the present invention to provide a slot insulating film forming apparatus for a rotor core having a shape.

[Outline of Invention]

The squirrel cage core slot insulating film forming apparatus of the present invention is provided with a steam supply part for blowing out steam, and the steam is blown from the steam supply part into the slot of the squirrel cage rotor core, which is formed by stacking steel plates, and the inner surface of the slot is passed. A degreasing device that removes oil adhering to the shaft, and a cored bar that is passed through the shaft hole of the squirrel cage rotor core. A receiving portion is provided on one end face of the rotor core so as to seal the shaft hole, and a tightening member that is brought into contact with the other end face of the squirrel cage rotor core so as to close the opening of the shaft hole is provided in the axial direction. The cage-shaped rotary iron core is movably provided, and the squirrel cage core is urged toward the receiving portion against the core by the tightening force applying mechanism so that the squirrel cage core is axially moved between the receiving portion and the fastening member. Tightening device for tightening and immersion tank that stores insulation treatment liquid The squirrel-cage rotor core, which has a shaft hole sealed by the tightening device and is axially tightened, is used as an insulating treatment liquid in a dipping tank in a state where air is pumped from the ventilation passage into the shaft hole. By dipping, the insulating treatment liquid adhering device for adhering the insulating treatment liquid to the inner surface of the slot from which the oil content has been removed by the degreasing device, and the insulating treatment liquid adhering to the vicinity of the slot on the one end face of the cage rotor core. Scraper scraped into the slot, air supply part that discharges excess insulation treatment liquid in the slot by passing air from the scraper side into the slot, insulation treatment liquid discharged from the throttle, and adheres to the outer peripheral surface of the cage rotor core The gradual liquid treatment device having a suction unit for sucking the insulating treatment liquid and returning it to the insulating treatment liquid adhering device, and a heating coil through which a high-frequency current is passed are provided. The one in which by induction heating cage rotor core formed by and a printing apparatus for printing a the insulating treatment solution adhering to the said slot.

Example of Invention

An embodiment in which the present invention is applied to a manufacturing process of a rotor of a squirrel cage induction motor will be described with reference to the drawings. First, the squirrel-cage rotor iron core (hereinafter, rotor iron core) 1 according to the present embodiment has a known configuration. That is, it is formed by punching electromagnetic steel sheets whose surfaces are insulated into a predetermined shape and laminating a large number of the punched sheets, and is provided with a shaft hole 1a for press-fitting a rotary shaft and a large number of slots 1b. Now, Fig. 1 shows this rotor core 1
1 shows a carrier device A for carrying a series of the above to each station that executes each process described below. In the figure, 2 is a guide rail, and 3 is a pallet movably provided on a pair of guide rails 2. The pallet 3 is provided with a support cylinder 4 integrally having a gear plate 4a at the upper end thereof via a bearing 5 so as to be rotatable. An upper support plate 6 is fixed to a nut 7 at a lower end portion of the support cylinder 4, a lower support plate 9 is fixed to the upper support plate 6 via a plurality of spacer rods 8, and a lower surface of the lower support plate 9 is further fixed. A clamp block 10 as a tightening member is fixed to the.
On the other hand, 11 is a pair of bearing columns standing on the upper surface of the gear plate 4a, in which vertically long bearing holes 11a are formed. Reference numeral 12 denotes a pair of movable claws, which are substantially L-shaped and have a central support shaft portion 12a protruding therefrom, and a plurality of laterally extending grooves formed on one side surface of the upper portion to form a meshing surface 12b.
Are formed. The movable claw 12 has a support shaft portion 12a fitted in the bearing hole 11a, and is rotatably supported by the bearing column 11 with the meshing surfaces 12b, 12b facing each other to form a jaw-shaped clamp. In addition, the compression springs 13 and 13 constantly urge the two meshing surfaces 12b and 12b in the direction of bringing them closer to each other, and the compression spring 14 provided between the support shaft portion 12a and the gear plate 4a always urges them upward. ing. Reference numeral 15 is a cored bar formed by integrally forming a disk-shaped receiving portion 15b on the lower end of a long shaft portion 15a. The engagement surface 12b of the movable claw 12 is engaged with the shaft portion 15a near the outer peripheral upper end. Is formed with a thread groove. The shaft portion 15a of the cored bar 15 penetrates the shaft hole 1a of the rotor core 1 received by the receiving portion 15b, and further penetrates through the clamp block 10, the lower support plate 9 and the support cylinder 4 in this order to obtain a movable claw. It meshes with 12. Therefore, in this state, since the movable claw 12 is constantly urged upward by the compression spring 14, the rotor core 1 is pulled upward by the receiving portion 15b of the cored bar 15 and the clamp block 10 is pulled.
And the receiving portion 15b axially pressurize the shaft hole 1a.
The upper and lower ends of the are sealed. Here, a cored bar 15 that is passed through the shaft hole 1a of the rotor core 1, and a receiving member that is provided integrally with the cored bar 15 and contacts the lower end face that is one end face of the rotor core 1a to seal the shaft hole 1a. A clamp block 10 that is provided movably in the axial direction with respect to the portion 15b and the core metal 15 and contacts the upper end surface that is the other end surface of the rotor core 1 to seal the shaft hole 1a constitutes a tightening device B. In this embodiment, the clamp block 10 moves in the axial direction relative to the core bar 15 as the core bar 15 moves in the axial direction. Then, the movable claw 12 and the compression spring 14
Urging the core bar 15 upwards urges the clamp block 10 against the core bar 15 in the direction of the receiving portion 15b, so that the rotor core 1 is pressed against the core bar 15b and the clamp block 10.
A tightening force applying mechanism C for tightening between and is constructed. Further, the shaft portion 15a of the core metal 15 is hollow and has an air passage 16 formed therein, and a through hole 16a which connects the air passage 16 and the shaft hole 1a of the rotor core 1 is formed. ,
As a result, air can be pressure-fed into the shaft hole 1a through the ventilation passage 16 by an air feeding means (not shown).
In this embodiment, among the above-mentioned configurations, the upper and lower support plates 6 and 9, the spacer rod 8 and the clamp block 10 are particularly used.
Also, the cored bar 15 is made of a non-magnetic material so as to prevent them from being heated as much as possible in the baking process described later.

Now, the steps executed in this embodiment will be described in order.

(1) Clamping Step In the clamping station, as shown in FIG. 2, a supply table 17 is provided below the conveying device A, and the rotor core 1 is sequentially supplied onto the supply table 17. . On the transfer device A side, an unclamp jig 18 is applied from above to each movable claw 12 and its supporting shaft portion 12a, and thus each movable claw 12 is pushed downward against the elastic force of the compression springs 13 and 14. In addition, the meshing surfaces 12b are separated from each other. A pedestal 19 for supporting the cored bar 15 in a standing state is provided below the supply table 17, and the pedestal 19 can be raised by a cylinder device (not shown). Then, the rotor core 1 is slid on the supply table 17 and supplied, and when the rotor core 1 reaches the position right below the clamp block 10 of the carrying device A, the positioning pin 20 is provided.
Abut and stop. Then, the pedestal 19 rises, and the shaft portion 15a of the cored bar 15 penetrates the shaft hole 1a of the rotor core 1 and projects above the support cylinder 4. Here, unclamp jig 1
8, the movable claw 12 is rotated by the elastic force of the compression spring 13, the meshing surface 12b is meshed with the shaft portion 15a of the core metal 15, and the elastic force of the compression spring 14 causes the movable claw 12 and thus the core. Gold 15 is pulled upward. As a result, the rotor core 1 is suspended below the clamp block 10 as shown in FIG. 1, and the rotor core 1 is axially arranged between the clamp block 10 and the receiving portion 15b of the core metal 15. And the shaft hole 1a is sealed. The rotor core 1 is sent to the next degreasing station in this state.

(2) Degreasing Step When the carrier A arrives at the degreasing station, the drive gear 21 provided there meshes with the gear plate 4a of the support cylinder 4 as shown in FIG. 3, and the support cylinder 4 and thus the rotor core 1
Is driven to rotate. Then, the nozzle 22 as a steam supply unit included in the degreasing device D provided in the degreasing station.
Is opposed to the opening of the slot 1b on the upper end surface of the rotor core 1, and high temperature steam is jetted downward from the nozzle 22. As a result, the working oil which is used when punching the electromagnetic steel sheet and remains on the inner surface of the slot 1b is washed out and removed. Since the rotor core 1 is rotated, the removal of the processing oil is sequentially performed for all the slots 1b.

In this way, if degreasing is performed using high temperature steam,
Unlike solvents such as acetone, water vapor is not toxic, so it is not necessary to consider the contamination of the working atmosphere. In addition, since water vapor originally has a lower permeability into the gap than a solvent such as acetone, and in particular, in this embodiment, the rotor core 1 is axially tightened in the degreasing step to bring the blanks into close contact with each other. Therefore, water vapor hardly penetrates between the blanks. Even if water vapor permeates between the blanks due to insufficient tightening force, the insulation treatment liquid is generally aqueous and therefore has good compatibility with water vapor (water droplets). There is no possibility that the permeation adversely affects the adhesion of the insulation treatment liquid in the next insulation treatment liquid adhesion step. Therefore, after completion of this degreasing step, the process can immediately proceed to the next insulating treatment liquid adhering step without passing through the auxiliary step for removing the solvent, so that the productivity can be improved. Moreover, there is a circumstance that this type of insulating treatment liquid exhibits optimum adhesiveness when the temperature of the rotor core 1 is about 70 ° C. or lower, but if high temperature steam is injected to degrease it, By properly setting the temperature and injection amount of water vapor, it becomes possible to heat the inner surface of the slot 1b to an optimum temperature and obtain good adhesion to the slot 1b. After the degreasing process is completed, the rotor core 1 is transported to the next insulation treatment liquid deposition station.

(3) Insulation Treatment Liquid Adhering Step The insulation treatment liquid adhering station is provided with an insulation treatment liquid adhering device E shown in FIG. In the figure, reference numeral 23 is a reserve tank provided on an elevating mechanism 24, and an immersion tank 25 is provided above the reserve tank. The insulating treatment liquid in the reserve tank 23 is pumped up by the pump 26 and is flowed to the rectifying plate 25.
It is supplied from the bottom to the immersion tank 25 through a. Immersion tank 2
The insulating treatment liquid overflowing from the No. 5 is received by the overflow tank 27 formed around the dipping tank 25, and is returned to the reflux pipe 28.
And is returned to the reserve tank 23. When the rotor core 1 arrives directly above the immersion tank 25, the lifting mechanism 24
Is activated and the reserve tank 23 is lifted until the liquid level in the dipping tank 25 immerses the upper end surface of the rotor iron 1. At the same time, air is pumped into the shaft hole 1a of the rotor core 1 through the ventilation passage 16 of the cored bar 15. Since the insulation treatment liquid flows from the bottom to the top in the immersion tank 25, the insulation treatment liquid flows into the slot 1b of the rotor core 1. At this time, since both ends of the shaft hole 1a of the rotor core 1 are sealed by the clamp block 10 and the receiving portion 15b of the cored bar 15, it is possible to prevent the insulating treatment liquid from entering the shaft hole 1a. . Moreover, particularly in the present embodiment, since air is pumped into the shaft hole 1a, even if there is a gap between the rotor core 1 and the clamp block 10 or the core metal 15,
It is possible to more reliably prevent the insulating treatment liquid from entering the shaft hole 1a. Therefore, unlike the conventional method in which the rotor core 1 is simply immersed in the tax-rolling treatment liquid, it is possible to reliably prevent the insulating treatment liquid from adhering to the shaft hole 1a. As a result, in order to smoothly press fit the rotary shaft, the shaft hole 1a has been conventionally used.
Where an insulating process liquid adhering to the inner surface or an insulating film which has been baked as it was had to be carried out, an auxiliary process requiring a lot of labor had to be carried out, but in the present embodiment, it was possible to omit it and improve the productivity. It can be further improved. In addition, since the rotor core 1 is immersed in the insulation treatment liquid while being clamped in the axial direction, it is possible to prevent the insulation treatment liquid from entering between the blanks, and thus the insulation treatment liquid that has penetrated between the blanks. Due to the decrease of the space factor of the rotor core 1 due to the above, increase of the magnetic resistance and thus the deterioration of the motor performance can be prevented. Furthermore, as described above, since it is possible to prevent the insulating treatment liquid from entering the shaft hole 1a and between the blanks, it is possible to minimize the waste of the insulating treatment liquid.

After that, when the elevating mechanism 24 is operated to lower the dipping bath 25, the rotor core 1 is taken out of the insulation treatment liquid, and the excess insulation treatment liquid is dripped. Therefore, the rotor core 1 is sent to the next liquid removal processing station.

(4) Liquid Removal Processing Step The liquid removal processing station is provided with a liquid removal processing device F including a scraper 28, a blow nozzle 29 as an air supply unit, and a suction nozzle 30 as a suction unit. In this liquid removing station, the rotor core 1 is rotated in the same manner as in the degreasing station. And first of all
As shown in the right half of the figure, the scraper 28 is directed to the upper end surface of the rotor core 1, the blow nozzle 29 is opposed to the upper end opening of the slot 1b, and is in contact with the outer peripheral surface of the rotor core 1. The suction nozzle 30 is addressed. At room temperature or heated air is jetted from the blow nozzle 29, and the insulating treatment liquid excessively attached in the slot 1b is discharged downward. The suction nozzle 30 is formed with a liquid receiving portion 30a for receiving the insulating treatment liquid discharged from the slot 1b, and the insulating treatment liquid received by the liquid receiving portion 30a is scraped off from the outer peripheral surface of the rotor core 1. It is returned to the reserve tank 23 of the insulation treatment liquid application station together with the insulation treatment liquid. The scraper 28 is located immediately after the blow nozzle 29 along the rotation direction of the rotor core 1, and the insulating treatment liquid scraped by the scraper 28 is blown by the blow nozzle 2.
Air jetted from the nozzle 9 passes through the slot 1b and is discharged into the liquid receiving portion 30a of the suction nozzle 30. After this,
As shown in the left half of FIG. 5, the suction nozzles 31 and 32 are respectively attached to the outer peripheral surface of the clamp block 10 of the transfer device A and the outer peripheral surface of the receiving portion 15b of the cored bar 15, and the insulation attached to those portions. The processing liquid is removed, and the reserve tank 23
Returned to. Next, although not shown, the receiving portion 15 of the cored bar 15
The bottom surface of b is washed with water. This is to prevent the insulating treatment liquid adhering to the receiving portion 15b from being baked in the next baking, so that the insulating coating film is gradually deposited by repeated use of the cored bar 15. After this, the rotor core 1 is sent to the printing station.

(5) Baking Process A baking device C as shown in FIGS. 6 and 7 is provided at the baking process station. In the figure, 33 is a base, 3
Reference numeral 4 denotes a coil holder 34 installed on a base 33, which constitutes a heating passage 35 along the guide rail 2, and a heating coil 36 formed by bending a hollow copper tube into a substantially U shape is housed therein. . The conveying device A is fed at a constant time interval by a feeding device (not shown) with the width dimension of the pallet 3 as one pitch, whereby the rotor core 1 passes through the heating passage 35 for a predetermined time. Therefore, by applying a high frequency current to the heating coil 36, the rotor core 1 is induction-heated. A plurality of dummy cores 38 that are vertically moved by a cylinder 37 are arranged below the base 33 and can enter the heating passage 35 through an opening 33a formed in the base 33. When a predetermined number of rotor cores 1 are not accommodated in the heating passage 35 at the start or end of the work, the dummy cores 38 are inserted into the heating passage 35 by an insufficient number of the cores. And heating coil 36
Uniform the load of to prevent uneven heating and protect the power supply. In addition, an opening 34a for ventilation is formed in the lower part of the side wall of the coil holder 34, so that the heating passage 3 is heated when the rotor core 1 is heated.
An ascending airflow is efficiently generated in the slot 5 and in the slot 1b, so that the gas and steam generated by heating can be smoothly discharged.

When the rotor core 1 is heated in this way, the insulating treatment liquid adhering to the inner surface of the slot 1b is baked to form an insulating coating. In this case, since the present invention uses the induction heating method, it is possible to directly heat the rotor core 1 itself, which requires heating, and the conventional baking that indirectly heats the rotor core from the outside in the electric furnace. Compared with the method, it is not necessary to heat unnecessary parts such as the furnace wall, so that energy efficiency can be improved. Moreover, particularly in this embodiment, the transport device A
Among them, the cored bar 15, the clamp block 10, the upper and lower support plates 6 and 7, and the spacer rod 8 which are located in or near the heating passage 35 are made of a non-magnetic material,
It is possible to selectively heat only the rotor core 1 while avoiding unnecessary heating of these, and thus it is possible to further improve energy efficiency. Furthermore, since the present invention uses the induction heating method, the penetration depth of the induction current generated in the rotor core 1 can be freely set by the frequency of the current passing through the heating coil 36. Therefore, by sufficiently increasing the power supply frequency as in this embodiment, it is possible to locally heat only the vicinity of the surface of the rotor core 1 by utilizing the so-called skin effect. These things are in slot 1b
In the baking process for baking the insulating treatment liquid adhering to the inner surface of the slot, it is originally ideal to locally heat only the inner surface of the slot 1b, and the induction heating method of the present invention is used. Means that the heating method is most suitable for the actual situation, and the energy efficiency can be remarkably improved without wasting energy. Further, since only the necessary portion can be heated in this way, the rotor core 1 and the carrier A after the baking step can be cooled quickly, and the productivity can be further improved.

When the baking process as described above is completed, the rotor core 1 is removed from the carrier A, and the carrier A is sent to the cooling station.

(6) Cooling process The cooling tank 3 as shown in FIG. 8 is installed in the cooling station.
9 is provided. Cooling water is supplied to the cooling tank 39 in an overflow state, and when the transport device A arrives directly above the cooling tank 39, the cooling tank 39 is lifted by an elevating device (not shown) and the transport device A is immersed in the cooling water. To As a result, the carrier device A can be cooled to the initial temperature, so that the carrier device A can be returned to the clamp station again for continuous production.

In the above-described embodiment, the rotor core 1 is axially clamped and the shaft hole 1a is sealed by the conveying device A throughout the entire process, but in the present invention, the degreasing process and the baking process are performed. The rotor core 1 does not necessarily have to be maintained in such a state. That is, the water vapor used in the degreasing process of the present invention has less permeability into the gap as compared with a solvent such as acetone as described above, and even if it penetrates, it may adversely affect the insulating treatment liquid adhering process. Since the rotor core 1 is not tightened in the axial direction in the degreasing process, there is little problem even if there is a slight gap between the blanks of the rotor core 1 and water vapor slightly permeates. . Further, in the baking process, even if there is a slight gap between the blanks of the rotor core 1, the insulating treatment liquid adhering to the inner surface of the slot 1b rarely enters the gap. Further, in the present embodiment, the pressurized air is pressure-fed into the shaft hole 1a of the rotor core 1 in the insulating treatment liquid attaching step. However, when the sealing property of the shaft hole 1a is sufficiently sealed, It is also possible to omit the pressure feeding of the pressurized air. Besides, the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

〔The invention's effect〕

As described above, since the degreasing process by the degreasing device is performed by passing water vapor in the slot, which is harmless and less likely to adversely affect the subsequent process, as described above, a solvent such as acetone is used. Unlike the above, there is no risk of contamination of the work environment, and the auxiliary process for removing the solvent is unnecessary. In addition, the insulating treatment liquid applying step by the insulating treatment liquid applying device,
Since the shaft center of the squirrel-cage rotor core is sealed by the tightening device and the squirrel-cage rotor core is clamped in the axial direction while the air is being pumped into the shaft hole, it is possible to penetrate the shaft hole. It is possible to eliminate the step of removing the insulating treatment liquid described above and prevent deterioration of motor performance due to the insulating treatment liquid that has entered between the blanks. Moreover, in the liquid removal processing step by the liquid removal processing device, excess insulation processing liquid adhering to the squirrel cage rotor core is removed and returned to the insulation processing liquid adhering device, so there is no wasteful consumption of the insulation processing liquid. Furthermore, since the baking process by the baking device is performed by the induction heating method, it is possible to directly heat the squirrel cage rotor core required for baking the insulation treatment liquid adhering to the inner surface of the slot, which significantly improves energy efficiency. obtain. As a result, the present invention has an excellent effect that the productivity can be improved with a small number of steps as a whole, and the performance of the motor and the energy efficiency can be improved.

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a vertical sectional side view of a conveying device, Fig. 2 is a front view of a clamp station, Fig. 3 is a side view of a degreasing station, and Fig. 4 is a deposition of an insulating treatment liquid. FIG. 5 is a vertical cross-sectional view of the apparatus, FIG. 5 is a partial cross-sectional view of a liquid removal treatment station, FIGS. 6 and 7 are side views and a front view showing a partially broken view of a baking apparatus, and FIG. 8 is a partial view of a cooling station. FIG. In the drawings, 1 is a squirrel-cage rotor core, 1a is a shaft hole, 1b is a slot, 10 is a clamp block (tightening member), 15 is a core metal, 15b is a receiving part, 16 is an air passage, 22 is a nozzle (steam). Supply unit), 25 is a dipping tank, 28 is a scraper, 29 is a blow nozzle (air supply unit), 30 is a suction nozzle (suction unit), 36 is a heating coil, A is a transfer device, B is a tightening device, and C is A tightening force applying mechanism, D is a degreasing device, E is an insulating treatment liquid adhering device, F is a liquid removing treatment device, and G is a baking device.

Claims (1)

[Claims] 1. A degreasing device for removing oil adhering to an inner surface of a slot by passing steam discharged from the steam supply section into a slot of a squirrel cage rotor core having steam supply sections for discharging steam. And forming a ventilation path for pumping air into the shaft hole of the squirrel cage rotor core, and sealing the shaft hole in the one end face of the squirrel cage rotor core. And a fastening member that abuts so as to stop the shaft-shaped opening of the squirrel cage rotor core so as to close the opening of the shaft hole so as to be movable in the axial direction. A clamping device that axially clamps the squirrel cage iron core between the receiving part and the tightening member by being urged toward the receiving part by the tightening force application mechanism, and the insulation treatment liquid is stored. Equipped with a dipping tank, the shaft hole is sealed by the tightening device. With the cage-shaped rotor core that is axially tightened together with the cage-shaped rotor core, the oil was removed by the degreasing device by immersing the cage-shaped rotor core in the insulation treatment liquid in the dipping tank in a state in which air was pumped from the ventilation passage into the shaft hole. An insulation treatment liquid adhering device for adhering the insulation treatment liquid to the inner surface of the slot, a scraper for scraping the insulation treatment liquid adhering to the vicinity of the slot on the one end face of the squirrel cage rotor core into the slot, and air from the scraper side into the slot Through the air supply portion for discharging the excess insulation treatment liquid in the slot through the insulation treatment liquid, the insulation treatment liquid discharged from the slot, and the insulation treatment liquid adhering to the outer peripheral surface of the cage rotor core. A liquid removal treatment device having a suction unit for returning to the above, and a heating coil through which a high-frequency current is passed, and the heating coil induction-heats the cage rotor core to Tsu formed by and a printing apparatus for printing a the insulating treatment solution adhering to the preparative squirrel cage rotating core slot insulating film forming apparatus.