JP2014099966A - Method of manufacturing squirrel-cage rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method of manufacturing a squirrel-cage rotor in which problem in terms of quality is less likely to occur, and insulation treatment can be applied between a conductor bar and a rotor core by simpler device and procedure.SOLUTION: A method of manufacturing a squirrel-cage rotor 50 includes a step for forming a conductor bar 7 by filling a slot 6, formed in a rotor core 1, with aluminum by aluminum die-casting process, and a step for applying an impact a plurality of times to the rotor core 1 after forming the conductor bar 7.

Description

  The present invention relates to a method for manufacturing a cage rotor.

  A squirrel-cage rotor of an induction motor includes a rotor core and a conductor bar. The rotor core is formed with a plurality of through holes (slots) arranged in the circumferential direction. The slots formed in the rotor core are filled with aluminum by aluminum die casting to form a conductor bar.

  When insulation treatment is not performed between the conductor bar and the rotor core, eddy current loss and stray load loss occur in the rotor, resulting in a reduction in efficiency of the motor. As a countermeasure against this problem, the cage rotor is heated and then cooled with water, so that the difference between the coefficient of linear expansion between the rotor core mainly composed of iron and the conductor bar composed mainly of aluminum The processing method which peels a conductor bar is disclosed by patent document 1, for example.

JP 2001-224152 A

  However, heating furnace equipment is required to heat the cage rotor. In the heating furnace equipment, since a plurality of rotors are heated at a time, there are problems that the number of inventory items and the number of process days are increased. Furthermore, since the heating is performed at a temperature of 400 to 450 degrees, there is a problem in terms of quality that the rotor core may be oxidized or thermally deformed.

  The present invention has been made in view of the above, and it is difficult to cause a problem in terms of quality, and a cage shape that can be insulated between the conductor bar and the rotor core with a simpler apparatus and procedure. It aims at obtaining the manufacturing method of a rotor.

  In order to solve the above-described problems and achieve the object, the present invention includes a step of filling a slot formed in a rotor core with aluminum by an aluminum die casting process to form a conductor bar, and a rotation after the conductor bar is formed. Applying a plurality of impacts to the core.

  According to the present invention, there is no problem in terms of quality, and there is an effect that an insulation process can be performed between the conductor bar and the rotor core with a simpler apparatus and procedure.

FIG. 1 is a diagram for explaining a method for manufacturing a cage rotor according to a first embodiment of the present invention, and is a side view of the cage rotor. FIG. 2 is a view of the cage rotor as viewed along the rotation axis. FIG. 3 is a partially enlarged view in which the portion A shown in FIG. 2 is enlarged. FIG. 4 is a diagram showing the relationship between the rotational speed and torque characteristics of an electric motor using a squirrel-cage rotor. FIG. 5 is a graph showing the relationship between the rotational speed of an electric motor using a cage rotor and efficiency characteristics.

  Below, the manufacturing method of the cage rotor concerning embodiment of this invention is demonstrated in detail based on drawing. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining a method for manufacturing a cage rotor according to a first embodiment of the present invention, and is a side view of the cage rotor. A squirrel-cage rotor 50 shown in FIG. 1 is a rotor used for an induction motor, and includes a rotor core 1 and a die cast part 2. A rotating shaft 3 is inserted in the center of the rotor core 1. The squirrel-cage rotor 50 is rotatable around the rotation shaft 3 in the induction motor.

  FIG. 2 is a view of the cage rotor 50 as viewed along the rotation axis 3. A plurality of slots 6 are formed in the rotor core 1 as through holes extending along the rotation shaft 3. The slots 6 are formed side by side along the circumferential direction. The rotor core 1 is configured by stacking iron plates punched into a predetermined shape so that a hole or slot 6 into which the rotating shaft 3 is inserted is formed.

  The die cast part 2 includes a conductor bar 7 made of aluminum filled in the slot 6 and end ring parts 13 provided on both sides of the rotor core 1 along the rotation shaft 3. The end ring portions 13 provided on both sides of the rotor core 1 are connected to each other through a conductor bar 7. The die cast part 2 is formed by integrally forming the conductor bar 7 and the end ring part 13 by an aluminum die casting process.

  Next, a method for manufacturing the cage rotor 50 will be described. First, the rotor core 1 is manufactured by stacking iron plates punched into a predetermined shape. Next, molten aluminum is filled into the slot 6 of the rotor core 1 by an aluminum die casting process, and the die cast part 2 including the conductor bar 7 and the end ring part 13 is formed. Next, the rotating shaft 3 is inserted and fixed to the rotor core 1. Next, the cage rotor 50 is cut with the required dimensional accuracy. Next, a plurality of impacts are applied to the surface of the cage rotor 50. For example, a plurality of impacts are applied to the surface of the cage rotor 50 from the direction perpendicular to the rotation shaft 3. In addition, the direction which applies an impact is not restricted to this.

  FIG. 3 is a partially enlarged view in which the portion A shown in FIG. 2 is enlarged. By applying an impact several times to the surface of the cage rotor 50, the conductor bar 7 is peeled from the rotor core 1 inside the slot 6, and an air layer is formed between the rotor core 1 and the conductor bar 7. 8 is formed.

  As a method for applying an impact to the surface of the cage rotor 50, for example, as shown in FIG. 1, a piston valve 14 having an impact member 5 attached to the tip may be used. If the impact member 5 collides with the surface of the squirrel-cage rotor 50 by reciprocating the piston valve 14, an impact can be applied to the surface of the squirrel-cage rotor 50.

  The impact member 5 is preferably made of a material that does not deform the surface of the squirrel-cage rotor 50 or the coaxiality between the rotor core 1 and the rotating shaft 3, for example, reinforced plastic such as polycarbonate. The number of impacts applied to the surface of the cage rotor 50 is arbitrarily set according to the diameter of the rotor and the number of slots 6.

  In the portion where the air layer 8 is formed, electrical contact between the rotor core 1 and the conductor bar 7 is lost, and short-circuit current between adjacent slots 6 is less likely to occur. Therefore, the eddy current loss and stray load loss of the induction motor can be suppressed, and the characteristics of the motor can be improved.

  FIG. 4 is a diagram showing the relationship between the rotational speed and torque characteristics of an electric motor using a squirrel-cage rotor. It can be confirmed that the torque curve 10 of the squirrel-cage rotor in which the impact is applied to the surface is larger than the torque curve 9 of the squirrel-cage rotor before the impact is applied to the surface.

  FIG. 5 is a graph showing the relationship between the rotational speed of an electric motor using a cage rotor and efficiency characteristics. The efficiency improvement can be confirmed in the efficiency curve 12 of the squirrel-cage rotor in which the impact is applied to the surface than in the efficiency curve 11 of the squirrel-cage rotor before the impact is applied to the surface. 4 and 5 as described above, it is confirmed that by applying an impact to the surface of the squirrel-cage rotor, the eddy current loss and stray load loss of the induction motor can be suppressed and the characteristics of the motor can be improved. .

  As described above, by applying an impact to the surface of the cage rotor 50 a plurality of times, eddy current loss and stray load loss of the induction motor can be suppressed and the characteristics can be improved. Accordingly, since the equipment is simpler than the equipment for heating and cooling, the production line can be inlined and downsized. Further, an insulation process can be performed between the rotor core 1 and the conductor bar 7 by a simple procedure of applying an impact. Moreover, it is possible to produce the product without increasing the number of inventory items and the number of process days, and it is possible to solve quality problems such as oxidation and thermal deformation due to high temperature.

  As described above, the cage rotor according to the present invention is useful for a method of manufacturing a cage rotor in which conductor bars are formed by an aluminum die casting process.

  DESCRIPTION OF SYMBOLS 1 Rotor core, 2 Die casting part, 3 Rotating shaft, 5 Impact member, 6 Slot, 7 Conductor bar, 8 Air layer, 9 Torque curve, 10 Torque curve, 11 Efficiency curve, 12 Efficiency curve, 13 End ring part, 14 Piston valve, 50 cage rotor.

Claims (3)

Filling a slot formed in the rotor core with aluminum by an aluminum die casting process to form a conductor bar;
Applying a plurality of impacts to the rotor core after forming the conductor bar, and a method of manufacturing a squirrel-cage rotor. Further comprising the step of inserting a rotating shaft into the rotor core;
2. The method for manufacturing a cage rotor according to claim 1, wherein in the step of applying an impact to the rotor core, the impact is applied from a direction perpendicular to the rotation axis.   3. The method of manufacturing a cage rotor according to claim 1, wherein, in the step of applying an impact to the rotor core, reinforced plastic is caused to collide with the rotor core.

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