JP2009171653A - Dust core for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dust core for a motor which secures the rigidity of a the core and the rigidity of a part toward roots of teeth from, in particular, a connecting point of the teeth and a yoke while making use of such an advantage of the dust core that the shape of the core for the motor is freely formed. <P>SOLUTION: The dust core 5 for the motor is obtained by pressure-molding magnetic material powder, and embedded with a T-shaped electromagnetic steel plate 2 in a portion straddling the teeth 51 of the dust core 5 for the motor and the yoke 52. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a dust core for a motor.

For example, as shown in Non-Patent Document 1, there are various types of motors.

  The structure of a two-phase induction motor (AC motor) is schematically shown in FIG. FIG. 11A shows a two-phase one, but there are other ones other than the two-phase one. 4 is a rotor, 41 is a rotating shaft, and 5 is an iron core.

  There is a brushless motor as shown in FIG. 11B as a DC motor having a similar structure.

  On the other hand, there is also a DC motor having a brush as shown in FIG. 11 (c). As a magnet (corresponding to the iron core 5) arranged on the outside of the rotor 4, an electromagnet having a winding 6 instead of a permanent magnet is used. May be used.

  Conventionally, electromagnetic steel sheets have been mainly used as materials for motor cores. An electromagnetic steel sheet is an excellent soft magnetic material, and has been most commonly used because an iron core can be manufactured immediately by punching and laminating into an appropriate shape.

  On the other hand, for small motors or for motors with complex iron cores that are required to fit in a limited space, it is difficult to punch out magnetic steel sheets to produce iron cores. In some cases, a powdered iron core obtained by pressure molding magnetic material powder such as the above is used.

  However, the dust core has problems in strength and durability. This is because the motor iron core is exposed to severe conditions by its own rotation and vibration even under normal use environment.

  For this reason, various attempts have been made to improve the pressure molding method and conditions in order to improve the strength and durability of the dust core. A typical method is to reinforce the dust core with other materials.

  For example, in Patent Document 1, the outside of the green compact is covered with a reinforcing material such as an iron plate.

  In Patent Document 2, a three-stage structure of upper and lower green compacts and an intermediate laminated steel sheet is adopted.

  In patent document 3 and patent document 4, the electromagnetic steel plate is embedded in the dust core.

In patent document 5, the electromagnetic fine wire is embedded in the dust core.
Illustrated Motor mechanism p71,69,31 Nippon Jitsugyo Publishing Co., Ltd. February 20, 1995 First edition JP 2000-224783 A JP-A-2005-304202 JP 2003-224940 A JP 2005-184872 A JP 2004-104893 A

In the methods described in Patent Document 1 and Patent Document 2, the shape of the iron core greatly depends on the shape of the reinforcing material or the laminated material, and there is a problem that the degree of freedom of the shape, which is an advantage of the dust core, is impaired.

  Further, in the methods described in Patent Document 3 and Patent Document 4, the electromagnetic steel sheet is embedded in the tooth portion or the yoke portion of the iron core, and there is nothing between the tooth portion and the yoke portion, that is, at the root portion of the tooth portion. It is not embedded and there is a problem with the strength of the part.

  Furthermore, the method described in Patent Document 5 has a problem that the strength is insufficient by itself.

  The present invention has been made to solve such problems as in the prior art, and while taking advantage of the dust core that the shape of the motor core can be freely produced, the strength of the iron core, particularly the tooth portion and the yoke portion. It aims at providing the powder iron core for motors which can ensure the intensity | strength of the part from the connection part of this to the base of a teeth part.

That is, the present invention is as follows.
(1) A powder iron core for a motor obtained by pressure-molding magnetic material powder, and a T-shaped electrical steel sheet is embedded in a portion straddling the tooth portion and the yoke portion of the motor dust core. A compact iron core for motors.
(2) A powder iron core for a motor obtained by pressure-molding magnetic material powder, and a T-shaped electromagnetic steel sheet and a fine electromagnetic wire in a portion straddling the teeth and yoke of the motor dust core Powder iron core for motors, characterized by embedding
(3) The dust core for motor according to (1) or (2), wherein the electromagnetic steel sheet is a non-oriented electrical steel sheet.
(4) The dust core for motors according to (1) or (2), wherein the electromagnetic steel sheet is a unidirectional electrical steel sheet.
(5) The dust core for motors according to (1) or (2), wherein the electromagnetic steel sheet is a bidirectional electromagnetic steel sheet.

According to the present invention, the strength of the iron core, in particular, the strength of the portion from the connecting portion between the tooth portion and the yoke portion to the root of the tooth portion, while taking advantage of the dust core that the shape of the motor iron core can be freely manufactured. It is possible to provide a dust core for a motor that can ensure the above.

Hereinafter, the background to the present invention and the embodiment of the present invention will be described.

  For example, as shown in FIG. 2, as an iron core 5 that can be accommodated in a cylindrical space indicated by a dotted line that does not have much room for the outer diameter of the rotor 4, the teeth portion 51 is parallel to the extending direction of the rotary shaft 41. Consider a configuration in which the winding 6 is provided near the root of the tooth portion 51 after being arranged and connected at the root portion of the yoke portion 52.

  In FIG. 2, in order to make it easy to see, a part of the number of the tooth portions 51 is omitted, but actually, the tooth portions 51 are arranged at intervals over the entire circumference of the yoke portion 52.

  In the iron core 5 made of the dust core 1, the tooth portion 51, which is also provided with the winding 6, is 180 ° opposite to the circumferential direction of the yoke portion 52 with respect to the tooth portion 51 provided with the winding 6. Constitutes magnetic poles that form magnetic fields having the same magnitude and opposite signs when energized, and these magnetic poles are connected via a yoke 52.

  If the iron core 5 having such a shape is to be manufactured by laminating electromagnetic steel plates, at the connecting portion between the root portion of the teeth portion 51 and the yoke portion 52, as shown in FIG. 2 has to be bent or manufactured by joining the iron cores laminated with the electromagnetic steel plates 2 at the connecting portion 53 as shown in FIG. In the figure, 7 and 8 respectively represent a bent portion and a joined portion of the electromagnetic steel sheet.

  In these methods, the distortion of the portion 7 where the electromagnetic steel plate 2 is bent and the slight air gap formed in the joint portion 8 between the iron cores laminated with the electromagnetic steel plates 2 inhibit the flow of magnetic flux and deteriorate the characteristics of the motor. Cause.

  With a powder iron core obtained by pressure-forming magnetic material powder such as iron powder, the iron core 5 having such a shape can be easily manufactured, and the flow of magnetic flux is smooth because there is no distortion or air gap. become.

  However, a dust core obtained by press-molding magnetic material powder such as iron powder is inevitably inferior to an iron core manufactured by laminating electromagnetic steel sheets in terms of strength and durability. For example, as shown in FIG. 5, if the iron core 5 having the same shape as that of FIGS. 3 and 4 is manufactured by a dust core, a portion extending from the connection portion 53 of the tooth portion 51 and the yoke portion 52 to the root of the tooth portion 51. Is easy to break.

  Then, the inventors considered embedding the electromagnetic steel sheet 2 in the dust core 1 for the purpose of improving the strength of the same part.

  However, as shown in FIG. 6, when the electromagnetic steel sheet 2 is separately embedded in the tooth portion 51 and the yoke portion 52 of the iron core 5 made of the dust core 1, the strength of the connection portion 53 between the teeth portion 51 and the yoke portion 52 is increased. The portion from the connecting part 53 of the tooth part 51 and the yoke part 52 to the root of the tooth part 51 was easily broken, and there was no effect in improving the strength.

  Accordingly, as shown in FIG. 7, the T-shaped electromagnetic steel sheet 2 is embedded in the portion straddling the tooth portion 51 and the yoke portion 52 to reinforce the strength, and the present invention has been achieved. It is.

  FIG. 1 is an enlarged bird's-eye view of the reinforcing portion. The iron core 5 of the motor is a powder iron core 1 obtained by press-molding magnetic material powder such as iron powder, and is T-shaped in a portion straddling the tooth part 51 and the yoke part 52 of the powder iron core 1 The electromagnetic steel plate 2 is embedded.

  By using an electromagnetic steel sheet to reinforce, the flow of magnetic flux is promoted, and not only the strength as the iron core but also the soft magnetism and the motor characteristics can be improved.

  Furthermore, since the part to be reinforced with the electromagnetic steel sheet is also a part that wants to change the direction of the magnetic flux passing through the part straddling the tooth part 51 and the yoke part 52 at right angles, it is preferable to use a non-oriented electrical steel sheet, Alternatively, it is more preferable to arrange two unidirectional electrical steel sheets at right angles to each other so that the direction of strong magnetism matches the direction before and after the passing magnetic flux bends at right angles.

  Or it is also preferable to arrange | position a two-way electrical steel sheet according to the direction before and behind the magnetic flux which passes two directions where the magnetism passes strong at right angle.

  Further, as shown in FIG. 8, when the T-shaped electromagnetic steel sheet 2 and the electromagnetic fine wire 3 are embedded in the portion straddling the tooth portion 51 and the yoke portion 52, the strength can be further improved. . In addition, the electromagnetic wire 3 embedded in the dust core 1 together with the magnetic steel sheet 2 further promotes the flow of magnetic flux, and further improves not only the strength as the iron core but also soft magnetism and motor characteristics. it can.

  For example, the electromagnetic wire is effective even if it is arranged straight across the portion between the tooth portion 51 and the yoke portion 52, but as shown in FIG. 8, before and after the passing magnetic flux bends at right angles in the extending direction of the electromagnetic wire. It is more preferable to match this direction.

About a brushless motor with an iron core shaped as shown in Fig.
Case 1: In the case of an iron core having a bent portion 7 of the electromagnetic steel plate 2 as shown in FIG.
Case 2: In the case of an iron core having a joint 8 of the electromagnetic steel plate 2 as shown in FIG.
Case 3: In the case of the iron core having only the dust core 1 as shown in FIG.
Case 4: In the case of an iron core in which the non-oriented electrical steel sheet 2 is separately embedded in the teeth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG.
Case 5: In the case of an iron core in which a T-shaped non-oriented electrical steel sheet 2 is embedded in a portion straddling the tooth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG.
Case 6: As shown in FIG. 7, the magnetic flux passing through the T-shaped bi-directional electrical steel sheet 2 in the portion straddling the tooth portion 51 and the yoke portion 52 of the dust core 1 and passing through the two strong directions. In the case of an iron core embedded in the direction before and after bending at right angles,
Case 7: In the case of an iron core in which a T-shaped non-oriented electrical steel sheet 2 and an electromagnetic wire 3 are embedded in a portion straddling the tooth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG.
FIG. 9 shows the motor efficiency at a rotation speed of 2000 rpm and a torque of 0.5 Nm, expressed as a ratio when the case 3 (in the case of an iron core having only a dust core) is set to 1. Here, the motor efficiency is the motor output divided by the power consumption.

  In the case of the iron core having the bent portion 7 of the electromagnetic steel plate 2 as shown in FIG. 3, the efficiency is the lowest. In the case of the iron core having the joint portion 8 of the electromagnetic steel plate 2 as shown in FIG. The efficiency of the case 3 was the same as that of the iron core having only the dust core as shown in FIG.

  In the case of the iron core in which the non-oriented electrical steel sheet 2 is separately embedded in the tooth part 51 and the yoke part 52 of the dust core 1 as shown in FIG. 6, the pressure of the case 3 as shown in FIG. Efficiency improved compared with the case of the iron core of only the powder iron core 1.

  In the case of the iron core in which the T-shaped non-oriented electrical steel sheet 2 is embedded in the portion of the case 5 between the tooth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG. .

  The magnetic flux passing through the two strong directions of the T-shaped bi-directional electrical steel sheet 2 in the portion of the case 6 between the tooth part 51 and the yoke part 52 of the dust core 1 as shown in FIG. In the case of an iron core embedded in the direction before and after bending at right angles, the efficiency was even higher.

  Even in the case of the iron core in which the T-shaped non-oriented electrical steel sheet 2 and the electromagnetic wire 3 are embedded in the portion of the case 7 that spans the teeth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG. showed that.

  Further, FIG. 10 shows the number of repetitions when the motor efficiency is decreased by 10% by repeating the operation of starting and stopping the operation at the rotation speed of 8000 rpm and the torque of 0.5 Nm with these motors.

  In the case of the iron core having only the dust core 1 as shown in FIG. 5 in the case 3, the efficiency was reduced with the smallest number of repetitions.

  Further, in the case of the iron core having the joining portion 8 of the electromagnetic steel plate 2 as shown in FIG. 4 in the case 2, the number of repetitions is almost the same as the case 3 in the case of the iron core having only the dust core 1 as shown in FIG. In the case of the iron core in which the non-oriented electrical steel sheet 2 is separately embedded in the teeth 51 and the yoke 52 of the dust core 1 as shown in FIG.

  In the case of an iron core in which a T-shaped non-oriented electrical steel sheet 2 is embedded in a portion of the case 5 between the tooth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG. The T-shaped bi-directional electrical steel sheet 2 is applied to the portion between the tooth portion 51 and the yoke portion 52 of the dust core 1 and before and after the magnetic flux passing through the two strong directions is bent at a right angle. In the case of an iron core embedded in accordance with the direction, or in a portion of the case 7 between the tooth portion 51 and the yoke portion 52 of the dust core 1 as shown in FIG. In the case of the iron core in which the thin wire 3 is embedded, the number of repetitions until the efficiency decreases is significantly increased as compared with the case 3 of the iron core having only the dust core 1 as shown in FIG.

Diagram for explaining an example of an embodiment of the present invention Diagram for explaining an iron core that can be stored in a cylindrical space, which appears in the explanation of the process leading to the present invention Diagram for explaining iron core with bent part of electrical steel sheet Diagram for explaining an iron core with a joint part of electrical steel sheet Diagram for explaining iron core with dust core only Diagram for explaining an iron core in which non-oriented electrical steel sheets are separately embedded in the teeth and yoke of a dust core Diagram for explaining an iron core in which a T-shaped unidirectional electrical steel sheet is embedded in a portion straddling a tooth portion and a yoke portion of a dust core Diagram for explaining an iron core in which a T-shaped electromagnetic steel sheet and an electromagnetic fine wire are embedded in a portion straddling a tooth portion and a yoke portion of a dust core Diagram showing how motor efficiency changes when each iron core is used Diagram showing how the number of repetitions of start and stop changes until the motor efficiency drops when each iron core is used Diagram for explaining motor type and structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Powder iron core 2 Magnetic steel sheet 3 Electromagnetic thin wire 4 Rotor 41 Rotating shaft 5 Iron core 51 Teeth part 52 Yoke part 53 Connection part 6 Winding 7 Bending part of magnetic steel sheet 8 Junction part of electromagnetic steel sheet

Claims (5)

A powder iron core for a motor obtained by pressure molding magnetic material powder, characterized in that a T-shaped electromagnetic steel sheet is embedded in a portion straddling the teeth portion and the yoke portion of the motor dust core. Powder iron core for motor. A powder iron core for a motor obtained by press-molding magnetic material powder, wherein a T-shaped electromagnetic steel sheet and an electromagnetic wire are embedded in a portion straddling the teeth portion and the yoke portion of the motor dust core. A compact iron core for motors. The dust core for a motor according to claim 1 or 2, wherein the electromagnetic steel sheet is a non-oriented electrical steel sheet. The dust core for a motor according to claim 1 or 2, wherein the electromagnetic steel sheet is a unidirectional electrical steel sheet. The dust core for a motor according to claim 1 or 2, wherein the electromagnetic steel sheet is a bidirectional electromagnetic steel sheet.

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