KR20030047184A - rotor of squirrel cage induction motor and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A rotator is provided to be capable of improving a motor characteristic by mixedly using aluminum and a metal having a higher conductivity than the aluminum. CONSTITUTION: A stator iron core(10) consists of a plurality of steel plates(10a) which are stacked such that stator slots(13) become continuous along an axis direction. The stator slots are formed on an inner surface of the steel plates which are formed with a radial shape. A rotator conductor(31) is formed by mixing a copper powder with a die-casting aluminum. End-rings(33) are configured at both ends of the rotator iron core to interconnect rotator conductors and is made of the same component as the rotator slots provided at the second slot.

Description

Rotor of squirrel cage induction motor and method for manufacturing the same

The present invention relates to a squirrel cage induction motor, and more particularly, to a rotor and a manufacturing method of a squirrel cage induction motor which can improve the characteristics of the electric motor by using a high conductivity copper powder as the rotor conductor.

In general, an electric motor is a machine that obtains rotational power by converting electrical energy into mechanical energy, and is roughly classified into an AC motor and a DC motor, and among them, an induction motor is a kind of AC motor.

The induction motor is composed of a stator and a rotor, and torque is generated in the rotor by a rotating magnetic field generated when an alternating current flows through the stator winding, thereby rotating the motor. The induction motor as described above has a squirrel cage induction motor in which aluminum rods form a rotor conductor according to the winding form of the rotor, and a winding induction motor in which the winding is connected to the rotor as well as the stator. wound-rotor induction motors.

Among these, the rotor structure of the squirrel cage induction motor will be described with reference to the accompanying drawings.

1A and 1B are cross-sectional and longitudinal cross-sectional views illustrating a rotor structure of a general squirrel cage induction motor, respectively. The rotor of the squirrel cage induction motor generates torque by interaction of induced current and magnetic flux by a stator winding (not shown). It consists of the rotor conductor 31 which generate | occur | produces, and the rotor iron core 10 of the magnetic body which forms the path | route of a magnetic flux. At this time, the rotor iron core 10 is a circular silicon steel plate 10a in which a plurality of rotor slots 13 are radially formed at predetermined intervals on the outer circumferential side of the rotor slot along the axial direction. It is composed of a plurality of laminated so as to be continuous, a high conductivity aluminum metal is inserted into the rotor slot 13 to form a rotor conductor (31). In addition, end-rings 33 are formed at both ends of the rotor conductor 31 to connect the rotor conductors to each other to form a circuit. At this time, the rotor conductor 31 and the end ring 33 is generally formed by a die casting method using aluminum.

The rotor of the squirrel cage induction motor configured as described above generates a rotational torque according to Fleming's left hand law by interacting with the magnetic flux while current flowed from the stator winding through the rotor conductor 31.

However, in order to improve the performance in the above-described induction motor, the resistance of the rotor conductor 31 should be small. However, the conductivity of aluminum applied to the rotor conductor 31 has a limit, and thus the rotor conductor has become an obstacle in improving the characteristics of the induction motor.

The present invention has been made to solve the above problems, an object of the present invention is a rotor of a squirrel cage induction motor that can improve the characteristics of the electric motor by using a combination of aluminum and metal having a higher conductivity as a rotor conductor and It relates to a manufacturing method.

1A and 1B are cross-sectional and longitudinal cross-sectional views showing a rotor structure of a general squirrel cage induction motor, respectively.

Figure 2 is a longitudinal cross-sectional view showing the rotor structure of the squirrel cage induction motor according to the present invention

3 is a flow chart showing a rotor manufacturing process of the squirrel cage induction motor according to the present invention.

Explanation of symbols on the main parts of the drawings

10: iron core 10a: steel plate

13: rotor slot 20: shaft

31: rotor conductor 33: end ring

40: copper powder 50: plating layer

In order to achieve the above object, the rotor of the squirrel cage induction motor according to the present invention is composed of a plurality of rotor iron core is formed by stacking a plurality of slots are formed radially at a predetermined interval so that the slot is continuous along the axial direction ; A rotor conductor provided in the slot and having copper powder mixed with die-cast aluminum; It is provided to connect the rotor conductors to both ends of the rotor iron core to each other to form a circuit, and includes an end ring made of the same components as the rotor conductor.

On the other hand, the method for manufacturing the rotor of the squirrel cage induction motor of one embodiment of the present invention comprises a punching step of forming a slot at a predetermined position of a thin steel plate using a press die; Laminating step of manufacturing a rotor iron core by aligning the punched steel sheet so that the slot is continuous along the axial direction; Put the rotor iron core into the mold and inject the conductor powder mixed with aluminum powder and copper powder in the proper ratio at both ends of the slot and the rotor iron core, and then heated to a temperature between the melting point of aluminum and the melting point of copper, the copper powder And a die casting step of forming the co-existing rotor conductor and the end ring.

According to another aspect of the present invention, a method of manufacturing a rotor of a squirrel cage induction motor includes a punching step of forming a slot at a predetermined position of a thin steel plate using a press die; Laminating step of manufacturing a rotor iron core by aligning the punched steel sheet so that the slot is continuous along the axial direction; The die casting step of forming the rotor conductor and the end ring in which the copper powder coexists by inserting the rotor iron core into the mold and injecting the aluminum molten liquid mixed with the copper powder in an appropriate ratio to both ends of the slot and the rotor iron core. Include.

Therefore, the present invention can significantly reduce the conductor resistance as the rotor conductor is formed of a combination of aluminum and copper powder having a higher conductivity than the aluminum, thereby providing an advantage of improving the characteristics of the electric motor.

Hereinafter, with reference to the accompanying drawings, a rotor and a manufacturing method of the squirrel cage induction motor according to a preferred embodiment of the present invention will be described in detail.

First, Figure 2 is a longitudinal cross-sectional view showing the rotor structure of the squirrel cage induction motor according to the present invention.

The squirrel cage induction motor according to the present invention is a stator (not shown), a rotor which forms a concentric circle with the stator and maintains a predetermined void in the inner circumference of the stator, and is pressed into the center of the rotor to end the rotational force of the rotor. It is largely composed of a shaft that transmits coaxially.

Among them, as shown in FIG. 2, the rotor is formed by stacking a plurality of slots 13 radially formed with a predetermined interval so that the slots are continuous along the axial direction. An iron core 10, a rotor conductor 31 provided in each of the slots and generating torque by current induced from the winding of the stator, and a rotor conductor connected to both ends of the rotor iron core, respectively. It consists of an end ring 33 forming a circuit of.

Although the steel plate 10a constituting the rotor iron core is not shown in detail, an indentation hole in which a shaft 20 is installed in a center of the annular silicon steel plate is formed, and a plurality of indentations are formed on the outer periphery side of the indentation hole. The slot 13 is formed radially. At this time, the rotor conductor 31 provided in the slot is a form in which a large amount of copper powder 40 is mixed with the die-cast aluminum. The reason why the copper powder 40 is mixed with the rotor conductor 31 is because the conductivity of copper is higher than that of aluminum, so that the conductor resistance can be remarkably reduced. In this case, the current induced in the rotor conductor is The small resistance allows for greater torque with the rotating flux.

At this time, the larger the amount of the copper powder 40, the more advantageous it is to improve the characteristics of the electric motor.

The end ring 33 is also preferably composed of the same components as the rotor conductor 31. Of course, in the case of the end ring 33 may be made of only aluminum as in the conventional, but the end ring also acts as a resistance bar copper powder 40 is mixed in the same amount as the rotor conductor 31 It is advantageous in terms of motor characteristics.

On the other hand, when the copper powder is mixed in the rotor conductor 31 has the advantage that the performance is improved by reducing the conductor resistance, there is a disadvantage that a high resistance reaction layer is formed between the aluminum and the copper powder (40). Such a reaction layer influences the path of the secondary current, and as a result, the secondary current is concentrated on one side having good coupling with the end ring, and thus there is a concern that the characteristics of the motor may be deteriorated. In order to solve this problem, the present invention proposes that a separate plating layer 50 is formed on the interface between the copper powder 40 and aluminum. At this time, the plating layer 50 is a nickel coating film coated on the outside of the copper powder 40, serves to remove the reaction layer between copper and aluminum.

The rotor of the squirrel cage induction motor configured as described above is manufactured through the following process, which will be described in detail below.

As shown in FIG. 3, first, a press injection hole through which the shaft 20 is press-fitted in the center of the thin silicon steel sheet 10a and a plurality of first slots 13 formed radially on the outer circumferential side are formed by using a press die. The punching step S10 is performed.

At this time, not only mechanical stress such as torsion remains in the steel sheet 10a during the above-mentioned punching step, but also the electrical characteristics of the steel sheet are destroyed. In order to solve this problem, a heat treatment step (S20) of applying a heat treatment to the punched steel sheet to remove the mechanical stress and at the same time to restore the electrical characteristics is performed.

Next, the lamination step (S30) of manufacturing the rotor iron core 10 by arranging the heat-treated steel sheet so that the slots 13 are continuous along the axial direction, and then fixing them by welding or fixing them by riveting or clamping. Is performed. At this time, the lamination step may be preceded by the heat treatment step.

After the rotor iron core 10 is completed through the above-described process, the die casting step S50 having the rotor conductor 31 and the end ring 33 through the slot 13 is performed in two ways as follows. Can be achieved by

First, according to one embodiment of the present invention, the die casting step (S50) is a slot 13 and the conductor powder in which the rotor iron core 10 is put in a mold and aluminum powder and copper powder 40 are mixed at an appropriate ratio. It is injected into both ends of the iron core and heated to an appropriate temperature, thereby forming an end ring with the rotor conductor mixed copper powder. At this time, the temperature applied to the rotor iron core 10 is the temperature between the melting point of aluminum and the melting point of copper. In this case, since the melting point of aluminum is lower than that of copper, aluminum forms a rotor conductor 31 and an end ring 33 in the liquid state along the shape of the mold, and copper keeps the powder state intact. do. Therefore, when the aluminum melt is solidified, a rotor conductor and an end ring in which copper powder is mixed with aluminum as a main component may be formed in a portion where the rotor slot and the end ring are formed.

Next, according to another embodiment of the present invention, the die casting step (S50) is to insert the rotor iron core 10 into a mold and the aluminum melt in which the copper powder 40 is mixed in a proper ratio in advance with the slot 13 Injecting to both ends of the iron core 10 and pressurizing, thereby forming the rotor conductor 31 and the end ring 33 mixed with the copper powder. In this case, it is obvious that the temperature of the aluminum melt should be lower than the melting point of copper.

On the other hand, in order to effectively remove the reaction layer between the copper powder 40 and aluminum, the coating step (S40) for forming a plating layer on the copper powder before the die casting step (S50) described above should be preceded. That is, in the coating step S40, a plating layer containing nickel as a main component may be formed on the outer side of the copper powder by using a method of impregnating the copper powder 40 before die casting with a nickel coating agent.

So far, the present invention has been described with reference to preferred embodiments thereof, and one of ordinary skill in the art to which the present invention pertains may implement the modified embodiment within the essential technical scope of the present invention. Here, the essential technical scope of the present invention is shown in the claims, and the modified forms within the equivalent range will be construed as being included in the present invention.

In the rotor of the induction motor and a method of manufacturing the same according to the present invention, as the rotor conductor is formed by mixing aluminum and copper powder having higher conductivity than the aluminum, the conductor resistance can be remarkably reduced, thereby improving the characteristics of the motor. It provides an effect that can be improved.

Claims (7)

A rotor iron core configured by stacking a plurality of steel sheets in which a plurality of slots are formed radially at predetermined intervals such that the slots are continuous along the axial direction; A rotor conductor provided in the slot and having copper powder mixed with die-cast aluminum; Rotor of the squirrel cage induction motor including an end ring made of the same component as the rotor conductor, which is provided to connect the rotor conductors to both ends of the rotor iron core to each other. The method of claim 1, The rotor conductor is a rotor of a squirrel cage induction motor, characterized in that a separate plating layer for removing the reaction layer between aluminum and copper is further formed on the copper powder. The method of claim 2, The plating layer is a rotor of the squirrel cage induction motor, characterized in that the nickel coating film. A punching step of forming a slot in a predetermined position of a thin steel sheet using a press die; Laminating step of manufacturing a rotor iron core by aligning the punched steel sheet so that the slot is continuous along the axial direction; Put the rotor iron core into the mold and inject the conductor powder mixed with aluminum powder and copper powder in the proper ratio at both ends of the slot and the rotor iron core, and then heated to a temperature between the melting point of aluminum and the melting point of copper, the copper powder A rotor manufacturing method of a squirrel cage induction motor comprising a die casting step of forming a co-existing rotor conductor and the end ring. The method of claim 4, wherein Before the die casting step is performed, a rotor manufacturing method for a squirrel cage induction motor further comprising a coating step of forming a plating layer on the copper powder. A punching step of forming a slot in a predetermined position of a thin steel sheet using a press die; Laminating step of manufacturing a rotor iron core by aligning the punched steel sheet so that the slot is continuous along the axial direction; The die casting step of forming the rotor conductor and the end ring in which the copper powder coexists by inserting the rotor iron core into the mold and injecting the aluminum molten liquid mixed with the copper powder in an appropriate ratio to both ends of the slot and the rotor iron core. Rotor manufacturing method of squirrel cage induction motor comprising. The method of claim 6, Before the die casting step is performed, a rotor manufacturing method for a squirrel cage induction motor further comprising a coating step of forming a plating layer on the copper powder.