JP4415679B2 - Induction motor rotor - Google Patents

Description

  The present invention relates to a rotor of an induction motor for use in an electric pump or the like, and more particularly to a technique effective when applied to correction of rotor unbalance.

  Conventionally, induction motors have been widely used as drive sources in electric pumps. The advantage of the induction motor is that it is easy to manufacture and has few failures because the number of components is small and the structure is simple.

  In recent years, electric pumps have a wide variety of uses, for example, used as a circulation pump for a floor heater. This type of electric pump is used in which a floor heater is installed indoors and is operated continuously day and night. Therefore, low noise and low vibration are strongly demanded as market demand specifications.

  One of the causes of noise and vibration is due to the unbalance of the rotor of the induction motor. If the unbalance amount is large, the induction motor as a drive source shakes greatly, and vibration and noise increase, which is transmitted to the floor heating equipment and eventually shakes indoor walls and the like, causing discomfort to the user. give.

  Here, as a cause of unbalance, a nest (air pool) generated when the rotor is die-cast aluminum, a problem of mounting accuracy of the shaft press-fitted into the rotor, and the like can be considered.

  As a technique for correcting the unbalance of the rotor, for example, Japanese Patent Application Laid-Open No. 2002-34215 discloses a technique for measuring an unbalance amount and an unbalance position and adding a weight to cancel the unbalance amount. Has been. Since this technique requires man-hours to correct the imbalance, it is not suitable for products produced in large quantities.

  As a technology that can solve such problems and cope with mass production and reduce man-hours, the unbalance amount and unbalance position are measured, and a drill is used to make a hole in the core of the rotor to cancel the unbalance. There is technology.

  However, in this technique, when the position of the caulking dowel (recessed portion) of the core portion of the rotor is processed using a drill in order to cancel the unbalance amount, the metal piece of the core portion is unstable. May remain.

  Next, this drilling will be described.

  4 is a sectional view showing a conventional induction motor, FIG. 5 is a view showing a rotor and a rotor core in the induction motor of FIG. 4, (a) is a front view of the rotor, and (b) is a diameter of the shaft. Sectional drawing of a direction, (c) is a side view of a rotor.

In FIG. 4, the induction motor has a load-side motor cover 5a and an anti-load-side motor cover 5b that form a housing integrally with each other, and the load-side bearing 4a is provided on the load-side motor cover 5a. The load side motor cover 5b holds the anti-load side bearing 4b. The shaft 2 is rotatably supported by the load side bearing 4a and the anti-load side bearing 4b. A rotor 3b is attached to the shaft 2, and an annular stator 1 is fixed to the outer periphery of the rotor 3b with a predetermined distance from the rotor 3b.

  Further, as shown in FIG. 5 (a), the rotor 3b is an electromagnetic steel sheet having a thickness of about 0.5 mm, which is punched into a predetermined shape, laminated in the axial direction and caulked together. And a rotor core 6b made of a thin steel plate. As shown in FIG. 5 (b) which is a radial sectional view of the shaft 2 and FIG. 5 (c) which is a side view of the rotor 3b, end rings 7 are positioned at both ends of the rotor core 6b. A plurality of rotor slots (secondary conductors) 8 that pass through the rotor core 6b and connect one end ring 7 and the other end ring 7 are integrally formed by aluminum die casting. Reference numeral 9 denotes a cooling fin, which is formed at the time of aluminum die casting.

  The rotor core 6b is provided with a skew when stacked for improving efficiency. Therefore, a hole 10b of about φ2 is provided. And the half-cut dowels 11b are caulked into the overlapping steel plates (see FIG. 6).

  Next, an unbalance correction method will be described with reference to FIGS.

  6A and 6B are explanatory views showing proper unbalance correction in the induction motor of FIG. 4, where FIG. 6A is a front view of the rotor, FIG. 6B is a side view of the rotor, and FIG. It is sectional drawing along the -A line. 7 is an explanatory view showing improper imbalance correction in the induction motor of FIG. 4, (a) is a front view of the rotor, (b) is a side view of the rotor, and (c) is (b) It is sectional drawing along the BB line of FIG.

To correct the unbalance, the rotor 3b is rotated by supporting the portion where the load side bearing 4a and the anti-load side bearing 4b of the shaft 2 are inserted in the state of FIG. 6, and the unbalance value and the unbalance position are automatically measured. Measure with a machine. And the hole 13 is drilled with the drill 12 in the specified position, weight is reduced, and an imbalance is corrected. This operation is performed at both ends of the rotor core 6b.
JP 2002-34215 A

  However, since the unbalanced position is unspecified, a hole 13 may be formed by the drill 12 at the position of the caulking dowel 11b of the rotor 3b (FIG. 7). At this time, the broken line portions of the steel plate in FIG. 7C are squeezed into the metal piece 14 that is not connected anywhere because the broken line portions are difficult to crimp. This metal piece 14 may not be removed even in a brushing or air blow process, and remains in the rotor core 6b in a very unstable state. If the operation is performed in this state, the metal piece 14 may come off and be caught between the gaps of the stator 1 and the rotor 3b, and abnormal noise may be generated.

  In order to suppress noise and vibration in the induction motor to a low level, it is necessary to reduce the unbalance value of the rotor 3b. As described above, as a means for correcting the unbalance, a hole is drilled in the rotor core 6b with the drill 12. However, when the dowel 11b for caulking the rotor core 6b is in the unbalanced position, if a hole is drilled with a drill, the metal piece is unstable in the rotor core 6b. The remaining metal piece was removed during operation and an abnormal noise was generated.

  Therefore, the present invention provides a rotation of an induction motor in which a metal piece does not remain in an unstable state even if an unbalance correction is performed when the position of a depressed portion that caulks the rotor core matches the unbalance position. The purpose is to provide children.

In order to solve this problem, the rotor of the present invention is a rotor that is rotatably mounted on an induction motor, and a plurality of thin steel plates are stacked and integrated with each other along the axial direction of the shaft. The rotor cores, end rings attached to both ends of the rotor core, and at least a part of the rotor cores are formed on the end rings, and the thin steel plates constituting the rotor core are mutually connected. So that at least a part of the depressed portion is covered with the end ring.
And a hole provided for skewing .

  According to the present invention, since the position of the depressed portion for caulking the rotor core is provided so as to partially cover the end ring or the end ring, the position and unbalance of the depressed portion for caulking the rotor core are provided. When the position matches, even if the hole is drilled and the unbalance correction is performed, an effective effect is obtained that the metal piece does not remain in an unstable state.

  As a result, the remaining metal piece does not come off during use and no abnormal noise is generated.

The invention according to claim 1 of the present invention is a rotor that is rotatably mounted on an induction motor, wherein a plurality of thin steel plates are laminated along the axial direction of the shaft and integrated with each other. A core, an end ring attached to each end of the rotor core, at least one part formed on the end ring, and a depressed portion for caulking the thin steel plates constituting the rotor core. The part is formed so as to cover the end ring, and is set for skewing.
This is a rotor having a pierced hole , and since the position of the depressed portion for caulking the rotor core is provided so as to partially cover the end ring, the depressed portion caulking the rotor core Even if the position of the portion and the unbalance position coincide with each other, even if a hole is drilled and the unbalance correction is performed, the metal piece does not remain in an unstable state.

  Hereinafter, the best mode for carrying out the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

(Embodiment 1)
1 is a sectional view showing an induction motor according to an embodiment of the present invention, FIG. 2 is a view showing a rotor and a rotor core in the induction motor of FIG. 1, (a) a front view of the rotor, and (b) a shaft. (C) Side view of the rotor, FIG. 3 is a diagram showing unbalance correction in the induction motor of FIG. 1 (a) Front view of the rotor, (b) Side view of the rotor, (c) (B) It is sectional drawing along CC line.

  In FIG. 1, the induction motor has a load-side motor cover 5a and an anti-load-side motor cover 5b that form a housing integrally with each other, and a load-side bearing 4a is provided on the load-side motor cover 5a. The load-side motor cover 5b holds the anti-load-side bearing 4b. The shaft 2 is rotatably supported by the load side bearing 4a and the anti-load side bearing 4b. A rotor 3a is attached to the shaft 2, and an annular stator 1 is fixed to the outer periphery of the rotor 3a at a predetermined interval from the rotor 3a.

5A, the rotor 3a is punched into a predetermined shape, and a plurality of rotors 3a are laminated along the axial direction of the shaft 2 and are caulked to be integrated with each other. It has a rotor core 6a made of a thin steel plate such as an electromagnetic steel plate of about 5 mm. As shown in FIG. 5B, which is a radial sectional view of the shaft 2, and FIG. 5C, which is a side view of the rotor 3a, end rings 7 are positioned at both ends of the rotor core 6a. A plurality of rotor slots (secondary conductors) 8 that pass through the rotor core 6a and connect the one end ring 7 and the other end ring 7 are integrally formed by aluminum die casting. Reference numeral 9 denotes a cooling fin, which is formed at the time of aluminum die casting.

  The rotor core 6a is provided with a skew when stacked for improving efficiency. Therefore, a hole 10a of about φ2 is provided. And, the half-cut dowels (recessed portions) 11a are caulked into the overlapping steel plates. The position of the dowel 11a is provided so that a part thereof is in the end ring 7 or on the end ring 7 (see FIG. 2).

  Next, an unbalance correction method will be described with reference to FIGS.

  To correct the unbalance, the rotor 3a is rotated by supporting the portion where the load side bearing 4a and the anti-load side bearing 4b of the shaft 2 are inserted in the state of FIG. 3, and the unbalance value and the unbalance position are automatically measured. Measure with a machine. And the hole 13 is drilled with the drill 12 in the specified position, weight is reduced, and an imbalance is corrected. This operation is performed at both ends of the rotor core 6a.

  At this time, since the unbalance position is unspecified, a hole 13 may be made by the drill 12 at the position of the caulking dowel 11a of the rotor 3a (see FIG. 3).

  However, according to the embodiment of the present invention, the position of the dowel 11a for caulking the rotor core 6a is provided so as to partially cover the end ring 7 made of die-cast aluminum. If the position of the dowel 11a for caulking the core 6a matches the unbalanced position, even if the hole 13 is drilled with the drill 12 and the unbalance correction is performed, the metal piece will not remain in an unstable state. During use, it will not come off and no abnormal noise will occur.

  Here, the dowel position greatly affects the electrical characteristics of the induction motor. That is, when aluminum is die-cast, aluminum flows into the skew hole, so that the secondary resistance is reduced. However, in the present invention, the influence on the electrical characteristics can be eliminated by setting the dowel position to 1.5 to 2 mm from the end face of the rotor slot to the shaft center.

  Although the dowel position can be set so that the aluminum portion of the end ring 7 is greatly inward (shaft side) without changing the dowel position, the dowel 11a is applied to the end ring. There is a risk of greatly affecting the characteristics.

  The rotor of the induction motor according to the present invention is not limited to an application for an electric pump, for example, and can be used for various electric devices using an induction motor that requires low noise and low vibration as a drive source.

Sectional drawing which shows the induction motor which is one embodiment of this invention The figure which shows the rotor and rotor core in the induction motor of FIG. The figure which shows the imbalance correction in the induction motor of FIG. Sectional view showing a conventional induction motor The figure which shows the rotor and rotor core in the induction motor of FIG. Explanatory drawing which shows the appropriate imbalance correction in the induction motor of FIG. Explanatory drawing which shows improper imbalance correction in the induction motor of FIG.

Explanation of symbols

2 Shaft 3a Rotor 6a Rotor core 7 End ring 11a Dowel (recessed part)

Claims (1)

A rotor rotatably mounted on an induction motor,
A rotor core in which a plurality of thin steel plates are laminated along the axial direction of the shaft and integrated with each other;
End rings respectively attached to both ends of the rotor core;
At least a part of the end ring is formed, and a depressed part for caulking the thin steel plates constituting the rotor core to each other ; and at least a part of the end ring
And a hole provided for skewing .

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