JP2006020425A - Rotor for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor for motor where there is no leakage of magnetic flux from a slot for N pole to a slot for S pole adjoining each other. <P>SOLUTION: This rotor for a motor is one where a plurality of pole pieces 12 are arranged radially at equal intervals, centering upon a rotating shaft 30, and magnets 20 are arranged in the slots 18 between adjacent pole pieces 12 and 12, and these are molded integrally. Each pole piece 12 is divided, and a wedge part 18 projects in its circumferential direction from the base of each pole piece 12, and at molding, this wedge part 18 is so molded as to be coupled integrally. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotor in a motor.

  Conventionally, the core of a stator (stator) and a rotor (rotor) is manufactured by punching and stacking a core plate made of a steel plate (see, for example, Patent Document 1).

  A conventional method for manufacturing the rotor of the present applicant will be described with reference to FIG.

  As shown in FIG. 7, the rotor core plate 100 is formed by laminating a plurality of substantially isosceles triangular pole pieces 104 from the outer periphery of a ring-shaped core back 102 and punching out the core plate 100 made of this steel plate. Thus, the rotor core 106 is manufactured.

  The magnet 108 is inserted between each pole piece 104 in the manufactured rotor core 106, and the rotor core 106, the magnet 108, and the shaft are integrally molded with a mold resin in a state where the shaft is arranged at the center of the rotor core 106, Manufactures rotors.

Such a rotor is used for a motor used in, for example, a direct drive washing machine using a brushless DC motor, and since it can be multipolarized using an inexpensive ferrite magnet as the magnet 108, a high torque can be obtained. Both the magnet torque by the magnet 108 and the reluctance torque by the pole piece 104 can be obtained.
JP 2002-247788 A

  In the rotor having the above-described configuration, as shown in the enlarged view of FIG. 7, the adjacent S pole piece 104 and the N pole piece 104 are connected by the core bag 102. To the south pole slot. Therefore, there is a problem that the magnetic characteristics are deteriorated and the rotational torque of the motor cannot be obtained sufficiently.

  Accordingly, in view of the above problems, the present invention provides a rotor for a motor that does not leak magnetic flux from an adjacent N pole slot to an S pole slot.

  In the first aspect of the invention, a plurality of pole pieces are arranged radially at equal intervals around the rotation axis, a magnet is arranged in a slot between the adjacent pole pieces, and the plurality of poles arranged radially. In the rotor of the motor in which the piece and the magnet are integrally molded with the mold resin, each of the pole pieces is divided, and the wedge portions protrude in the circumferential direction from both sides of the base portion on the inner peripheral side of each of the pole pieces, The motor rotor is characterized in that it is molded so that the wedge portions of the pole pieces are integrally connected when the molding is performed.

  The invention according to claim 2 is the rotor of the motor according to claim 1, wherein each of the pole pieces has an isosceles triangle shape.

  The invention according to claim 3 is the rotor of the motor according to claim 1, wherein a protrusion for supporting the magnet protrudes from a wedge portion of each pole piece.

  The motor according to claim 4 is the motor rotor according to claim 1, wherein the motor is a brushless motor.

  In the motor rotor according to the first aspect of the present invention, since the pole pieces are respectively divided, there is no connection between the slots, magnetic flux leakage does not occur between the S pole and the N pole, and the motor performance is improved. Can be increased. Moreover, since the wedge part protrudes from the base part of the pole piece and is molded so that these wedge parts are integrally connected, the pole piece divided by the centrifugal force is not pulled out.

  In the motor rotor according to the second aspect of the invention, since the pole piece has an isosceles triangle shape, the slot can be formed in a rectangular shape, and a quadrangular prism magnet can be inserted.

  In the motor rotor according to the third aspect of the present invention, since the projection for supporting the magnet protrudes from the wedge portion of the pole piece, the magnet can be stably accommodated in the slot by this projection.

  Hereinafter, a rotor 10 according to an embodiment of the present invention will be described with reference to FIGS.

  The motor of this embodiment is a brushless motor for direct drive used in a washing machine or the like, and is a rotor used in, for example, a brushless DC motor, a brushless synchronous motor, or a brushless servomotor.

(1) Structure of Rotor 10 The structure of the rotor 10 will be described together with its manufacturing method based on FIGS.

(1-1) First Step In the first step, the divided pole piece 12 is formed. As shown in FIG. 1, the pole piece 12 is formed by punching ten pole piece plates 14 in one row from a strip-shaped steel plate 26 and laminating them while caulking by a caulking portion 16. The pole piece 12 has an isosceles triangle shape in plan, and wedge portions 18 and 18 protrude from the inner peripheral base, that is, both sides of the root. Projections 22 and 22 for supporting the magnet 20 protrude at positions on the outer peripheral side of the wedge portion 18. Holding portions 24 and 24 for holding the magnet 20 protrude from both end portions on the outer peripheral side of the isosceles triangular pole piece 12.

  As described above, by placing the isosceles triangular pole piece plates 14 alternately in a single steel plate 26 so as to face each other, 10 pieces of the pole piece plates 14 can be efficiently obtained from the single steel plate 26. It can be punched out and wasteful parts can be reduced. Conventionally, the structure is such that a pole piece arranged in a ring shape is punched out, and thus a lot of useless portions are generated. However, in this embodiment, a steel plate can be used efficiently.

(1-2) Second Step In the second step, 20 pole pieces 12 on which the pole piece plates 14 are stacked are housed radially inside the mold around the rotation axis as shown in FIG. In this case, the wedge portion 18 is stored so as to be on the inner peripheral side.

(1-3) Third Step In the third step, as shown in FIG. 3, 20 magnets 20 are placed in 20 slots 28 formed between 20 radial pole pieces inside the mold. Insert each one. The magnet 20 is a rod having a substantially rectangular cross section. In this case, as shown in FIG. 3, the magnet 20 is held in the slot 28 by the protrusion 22 and the holding portion 24, and each pole piece 12 is alternately excited to the N pole and the S pole. . The hatched portion of the magnet 20 in FIG. 3 represents the position of the south pole, and indicates that the direction of the magnet 20 disposed in the slot 28 differs depending on the hatched position.

(1-4) Fourth Step In the fourth step, the 20 pole pieces 12 and the 20 magnets 20 arranged in the mold as described above are integrally molded with a mold resin. The frame 40 is manufactured. In this case, the center portion of the frame 40 on which the rotating shaft 30 is arranged is made of metal for fixing the rotating shaft 30 and is provided with a columnar fixing member 36 and is integrally formed with the pole piece 12 and the magnet 20. To do. At the time of molding, as shown in FIG. 5, a cylindrical cavity 34 is provided in the central portion of the rotor 10, and a fixing member is attached to the frame 40 on the left side of the cylindrical cavity 34. 36 is molded.

  Then, at the time of molding, a connecting portion 28 for integrally connecting the wedge portions 18 of the 20 radial pole pieces 12 in a ring shape as shown in FIG. 4 is formed of mold resin.

(1-5) Fifth Step When the molding is completed, the rotary shaft 30 is inserted into the fixed member 36 and the assembly of the rotor 10 is completed.

(2) The structure of the wedge part 18 of the pole piece 12 and its function The structure of the wedge part 18 will be described in more detail with reference to FIG.

The shape of the wedge portion 18 is an arc shape in which the inner peripheral side is concentric with the rotation axis as the center, and the outer peripheral side is a triangular shape inclined by θ ° with respect to the radial direction in order to support the magnet 20 having a rectangular cross section. is there. The dimension of the outer peripheral side of the wedge portion 18 is L. In this case, the dimension L is a distance from the end of the wedge portion 18 to the protrusion 22. The distance from the protrusion 22 to the protrusion 22 in this way is less retained by the mold resin at the protrusion 22, and therefore, the dimension from the protrusion 22 to the wedge portion 18 is set to L in consideration of safety. When the centrifugal force is F1, the mass of the rotor 10 is M, the radius is R, and the maximum rotational speed of the rotor 10 is N,

F1 = MR (2π / N) ² (1)

It becomes.

Since the outer peripheral side of the wedge portion 18 is inclined by θ ° with respect to the radial direction, the force F2 applied to the wedge portion 18 is

F2 = F1 / cos θ (2)

It becomes.

On the other hand, when the thickness of the wedge portion 18 in the stacking direction is h and the allowable pressure per unit area of the wedge portion 18 is P,

F2 <2LhP (3)

It is necessary to become.

From the above relationship, the dimension L is

L> MR (2π / N) ² / 2Phcosθ (4)

Therefore, the wedge portion 18 may be designed so as to satisfy the relationship of the expression (4).

  Since the wedge part 18 of the pole piece 12 is integrally formed by the ring-shaped connecting part 38 made of mold resin as described above, even if the rotor 10 rotates at a high speed, the wedge part 18 is held at the position of the wedge part and is centrifuged. The pole piece 12 is not pulled out by force.

  Further, since each pole piece 12 is divided and has no connection, magnetic flux does not leak between adjacent S pole and N pole slots, and motor performance can be improved. And the lamination | stacking thickness h of the pole piece 12 can be reduced by the part which this motor performance became high, and size reduction of a motor can be achieved.

  The present invention is suitable for a rotor in which a magnet is embedded with a mold resin, and is particularly suitable for a brushless DC motor, a brushless synchronous motor, and a brushless servomotor rotor.

It is a top view of the pole piece board in the steel plate which shows one Embodiment of this invention. It is a top view of the steel plate before punching a pole piece board, (a) is a top view which distribute | arranged the pole piece radially, (b) is a side view of a pole piece. It is a top view of the state which inserted the magnet in the pole piece arranged radially. It is a top view of the rotor which performed the molding. It is a half longitudinal cross-sectional view of a rotor. It is an enlarged view which shows the structure of a pole piece. It is a top view of the state which inserted the magnet in the pole piece in background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rotor 12 Pole piece 14 Pole piece board 16 Caulking part 18 Wedge part 20 Magnet 22 Protrusion 24 Holding part 26 Steel plate 28 Slot 30 Rotating shaft 34 Cavity part 36 Fixing member

Claims (4)

A plurality of pole pieces are arranged radially at equal intervals around the rotation axis,
Magnets are arranged in slots between the adjacent pole pieces,
In the rotor of the motor in which the plurality of pole pieces and magnets arranged radially are molded integrally with a mold resin,
Each of the pole pieces is divided,
A wedge part projects in the circumferential direction from both sides of the base part on the inner peripheral side of each pole piece,
A motor rotor, wherein the pole portions are molded so that the wedge portions of the pole pieces are integrally connected when the molding is performed. The rotor of the motor according to claim 1, wherein each of the pole pieces has an isosceles triangle shape. The rotor of the motor according to claim 1, wherein a protrusion supporting the magnet protrudes from a wedge portion of each pole piece. The rotor of the motor according to claim 1, wherein the motor is a brushless motor.

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