JP2014128069A - Rotor for cage-type induction motor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time of work for fixing a rotor bar of a rotor of a cage-type induction motor within a slot of a rotor core.SOLUTION: A rotor for a cage-type induction motor comprises: a rotary shaft; a core 12 in which a plurality of steel plates are laminated axially while being spread vertically to an axial direction of the rotary shaft and forming a plurality of slots 13 circumferentially spaced apart from each other in the outer circumference, and which is mounted to the rotary shaft in such a manner that the plurality of slots 13 of the plurality of steel plates are disposed side by side in the axial direction, respectively; and a plurality of rotor bars 20 inserted into the plurality of slots 13 and extending axially, respectively. Both ends of each of the plurality of rotor bars 20 in the axial direction are spread while being divided vertically to the axial direction, so as to be pressed to the axial end portion of the slot 13 and fixed to the slot 13.

Description

  The present invention relates to a rotor of a squirrel-cage induction motor including an iron core and a rotor bar, and a manufacturing method thereof.

  A squirrel-cage induction motor has a simpler structure and is more robust than a wire-wound induction motor or a DC motor, but it has a rush current (3-8 times the rated current) at start-up that other types of motors do not have. Occur. This event gives thermal stress or electromagnetic force to the rotor bar, and in the worst case, it develops into an event of fatigue and crack initiation or breakage.

  In order to prevent this incompatibility event, it is necessary to fix the rotor bar firmly in the slot (groove) of the rotor core.

  Conventionally, as a method of firmly fixing the rotor bar to the slot of the rotor core, swaging is performed by striking the rotor bar from the outer circumferential direction, and the rotor bar is spread in the circumferential direction so that it is fixed to the slot so that it does not move in the longitudinal direction (axial direction). It is fixed to. In addition, regarding the length to which swaging is performed, it is necessary to reduce the resonance stress generated in the rotor bar of the rotor as much as possible in each iron core length and to set the swaging length to prevent breakage of the rotor bar (Patent Document) 1).

Japanese Patent Laid-Open No. 11-18344

  In the conventional caulking method of the rotor bar, it is necessary to set the swaging length as described above. The longer the iron core length, the longer the swaging length, and the longer the swaging operation is.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an object of the present invention to shorten an operation time for firmly fixing a rotor bar of a rotor of a squirrel-cage induction motor to a slot of a rotor core.

  In order to achieve the above object, a squirrel-cage induction motor rotor according to the present invention includes a rotating shaft and a plurality of slots that extend in a direction perpendicular to the axial direction of the rotating shaft and are circumferentially spaced from each other on the outer periphery. A plurality of steel plates formed with a plurality of steel plates are laminated in the axial direction, and inserted into each of the plurality of slots and the iron core attached to the rotating shaft so that the plurality of slots of the plurality of steel plates are aligned in the axial direction. A plurality of rotor bars extending in the axial direction, and a rotor of a squirrel-cage induction motor, wherein both ends of the plurality of rotor bars in the axial direction are divided and expanded in a direction perpendicular to the axial direction. It is pressed against the axial end of the slot and is fixed to the slot.

  Also, in the method of manufacturing a squirrel-cage induction motor rotor according to the present invention, a rotating shaft and a plurality of slots are formed on the outer periphery so as to extend perpendicularly to the axial direction and are spaced apart from each other in the circumferential direction. A plurality of steel plates are laminated in the axial direction, and an iron core attached to the rotating shaft is inserted in each of the plurality of slots in the axial direction so that the plurality of slots of the plurality of steel plates are aligned in the axial direction. A rotor for a cage induction motor comprising a plurality of extending rotor bars, a slit forming step of forming slits at both axial ends of the plurality of rotor bars, and after the slit forming step, A rotor bar insertion step of inserting the plurality of rotor bars into each of the slots; and after the rotor bar insertion step, widening the slit Having a fixing step of fixing the rotor bars in the slots against the serial rotor bars in the axial end portion of the slot, and characterized by.

  According to the present invention, it is possible to shorten the working time for firmly fixing the rotor bar of the rotor of the squirrel-cage induction motor to the slot of the rotor core.

The partial front which shows the state immediately after inserting a rotor bar in the slot of an iron core in the manufacture process of the rotor of a cage induction motor concerning the present invention, and shows the portion on the most front side when a rotor is seen from the perimeter side It is a figure, Comprising: It is an I direction arrow line view of FIG. FIG. 2 is a partial side view of the vicinity of the outer periphery of the rotor of the squirrel-cage induction motor of FIG. 1 and is a view in the direction of the arrow II in FIG. 1. It is a flowchart which shows the procedure of the manufacturing method of the rotor of the cage induction motor which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a state immediately after a rotor bar is inserted into a slot of an iron core in a manufacturing process of a rotor of a squirrel-cage induction motor according to the present invention, and the foremost part when the rotor is viewed from the outer peripheral side. FIG. 3 is a partial front view showing the I direction in FIG. 2. 2 is a partial side view of the vicinity of the outer periphery of the rotor of the squirrel-cage induction motor of FIG. 1, and is a view taken in the direction of the arrow II in FIG. FIG. 3 is a flowchart showing a procedure of a method for manufacturing a rotor of a cage induction motor according to the present invention.

  The rotor 10 of this embodiment is fixed to a rotating shaft 11 and includes an iron core 12 and a rotor bar 20. The iron core 12 is obtained by laminating a plurality of disc-shaped steel plates in the axial direction. Each disk extends vertically in the axial direction, and a hole through which the rotating shaft 11 passes is formed in the center. The iron core 12 is fixed to the rotating shaft 11.

  A plurality of slots (grooves) 13 extending in the axial direction along the outer periphery of the iron core 12 are formed at intervals in the circumferential direction. Each slot 13 is formed with a narrow opening 14 having a width facing the outer periphery, and is narrower than the wide portion 15 at the back.

  A procedure for inserting and fixing the rotor bar 20 in the slot 13 will be described.

  Before inserting the rotor bar 20 into the iron core 12, slits 16 are formed at both ends of the rotor bar 20, and further, an advancement stop 17 is formed at the innermost part of the slit 16 (step S1). The progress stop 17 is, for example, a circular through-hole penetrating along the surface of the slit 16.

  Next, the rod-shaped rotor bar 20 extending in the axial direction is inserted into the wide portion 15 of the slot 13 in the axial direction (step S2). 1 and 2 show the situation at the end of this step. At this time, both ends of the rotor bar 20 protrude from both ends of the iron core 12 in the axial direction. At this time, the two stop stoppers 17 formed on the rotor bar 20 are both inside the axial end of the iron core 12.

  Next, the slits 16 at both ends of the rotor bar 20 are widened (step S3). For example, the slit 16 can be widened by driving a wedge (not shown) into the slit 16. At this time, the advancement stop 17 prevents the slit 16 from further extending to break the rotor bar 20. By opening the slit 16 in this way, the rotor bar 20 is pressed against the axial end of the slot 13 and fixed. At this time, since the narrow narrow opening 14 is formed facing the outer periphery of the slot 13, the rotor bar 20 does not move in the outer peripheral direction and is not detached from the slot 13.

  According to this embodiment, the rotor bar 20 can be fixed in the slot 13 by a simple operation in a short time compared with the case where the rotor bar 20 is swaged.

  As mentioned above, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

DESCRIPTION OF SYMBOLS 10 ... Rotor 11 ... Rotating shaft 12 ... Iron core 13 ... Slot (groove)
14 ... Opening 15 ... Wide part 16 ... Slit 17 ... Progress stop 20 ... Rotor bar

Claims (3)

A rotation axis;
A plurality of steel plates, each extending in a direction perpendicular to the axial direction of the rotating shaft and having a plurality of slots formed on the outer periphery at intervals in the circumferential direction, are laminated in the axial direction, and each of the plurality of slots of the plurality of steel plates Cores attached to the rotary shaft so that the
A plurality of rotor bars inserted in the plurality of slots and extending in the axial direction;
A squirrel-cage induction motor rotor,
Both ends of each of the plurality of rotor bars in the axial direction are divided and expanded in a direction perpendicular to the axial direction so as to be pressed against the axial ends of the slots and fixed to the slots. Rotor for induction motor. A rotation axis;
A plurality of steel plates, each extending in a direction perpendicular to the axial direction of the rotating shaft and having a plurality of slots formed on the outer periphery at intervals in the circumferential direction, are laminated in the axial direction, and each of the plurality of slots of the plurality of steel plates Cores attached to the rotary shaft so that the
A plurality of rotor bars inserted in the plurality of slots and extending in the axial direction;
A method of manufacturing a rotor of a cage induction motor comprising:
A slit forming step of forming slits at both axial ends of each of the plurality of rotor bars;
A rotor bar inserting step of inserting the plurality of rotor bars into each of the slots after the slit forming step;
After the rotor bar insertion step, an adhering step of pressing the rotor bar against the axial end of the slot by widening the slit to fix the rotor bar to the slot;
And a method of manufacturing a squirrel-cage induction motor rotor.   3. The advancement stop forming step of forming an advancement stop for stopping the progress of the slit at the innermost position of the slits at both ends of the rotor bar before the rotor bar insertion step. A method of manufacturing a squirrel-cage induction motor rotor.

Images