JPH11206051A - Rotor structure of internal magnetic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a reluctance torque large, without lowering the permeability of a q-axis magnetic flux path of rotor core, even under a loading conditions, and to improve motor output while keeping the tightening effect of the rotor core as it is. SOLUTION: In a rotor structure of an internal magnetic motor, in which a field permanent magnet 2 is inserted to a magnet inserting hole 1a formed at the inside of a rotor core 1 which is formed by laminating electromagnetic plates and then caulking them, the position of caulking part 3 of the laminated electromagnetic steel plate is located at an area which does not affect the repulsive operation of armature in the q-axis direction of the rotor. A bridge 5 is provided on the magnetic pole center axis dividing the magnet inserting hole 1a into two sections, and the caulking porting 3 is provided on the bridge 5. As a result, the reduction in the permeability of the upper part of magnet of rotor core can be set to a minute value and the magnetic characteristic (permeability) of this part can be reduced deliberately by providing the caulking portion of the bridge and amount of permanent magnet to be reduced by reducing leakage magnetic flux of magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor structure of an inner magnet type motor, and more particularly to a rotor structure in which a swaging position is limited.

[0002]

2. Description of the Related Art Conventionally, a method of fastening a rotor laminated electromagnetic steel sheet of an inner magnet type motor is as shown in FIGS. FIG. 4 shows a conventional rotor core structure with four poles and a center bridge, and FIG. 5 shows a conventional six pole rotor core structure without a center bridge. A permanent magnet 3 is a caulking portion, and 5 is a bridge portion. The rotor of the inner magnet type motor has a cylindrical shape, and is formed by laminating electromagnetic steel sheets and forming a caulking portion 3.
Magnet insertion hole 1 formed inside swaged rotor core 1
This is a structure in which the field permanent magnet 2 is inserted into a. Conventionally, the caulking portion 3 for preventing the magnetic steel sheets from being disintegrated is set outside (in the case of FIG. 4) or outside and inside (in the case of FIG. 5) of the field permanent magnet 2. Was.

[0003]

However, in the prior art, when the central portion of the core outside the field permanent magnet 2 is caulked, a history of the deterioration of the magnetic properties is received due to the processing strain at the time of pressing. When there is no load, that is, when the magnetic flux passing through the core outside the field permanent magnet is only the magnet magnetic flux, the magnetic flux distribution in this portion is as shown in FIG. [T], and the magnetic permeability is not significantly reduced even if the magnetic properties are deteriorated due to the processing strain. However, under load, the magnetic flux distribution is shown in FIG.
When there is an armature reaction in the q-axis direction, a high magnetic flux density of 1.8 to 2.0 [T] is obtained, and the magnetic permeability is significantly reduced. For this reason, in the case of the internal magnet type motor that generates reluctance torque using the armature reaction magnetic flux, there is a problem that the generated torque is reduced. In FIG. 6, reference numeral 4 denotes a stator. Accordingly, it is an object of the present invention to improve the motor output without reducing the permeability of the q-axis magnetic flux path of the rotor core even under load, increasing the reluctance torque, and maintaining the effect of fastening the rotor core.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a rotor for an internal magnet type motor in which a field permanent magnet is inserted into a magnet insertion hole formed inside a rotor core formed by laminating and crimping electromagnetic steel sheets. In the structure, the position of the swaged portion of the laminated electromagnetic steel sheet is a place that does not affect the armature reaction in the q-axis direction of the rotor. An embodiment in this case includes the following structure. (1) A bridge portion is provided on the center axis of the magnetic pole that divides the magnet insertion hole into two, and the caulking portion is provided in the bridge portion. (2) Bridge portions are provided at both ends of the magnet insertion hole, and holes for preventing magnetic flux leakage in the circumferential direction of the rotor are provided. The caulking portion is connected to the bridge portion and a hole for preventing magnetic flux leakage. It is provided at a position close to. (3) At the yoke portion below the magnet insertion hole of the rotor core, the caulking position of the laminated electromagnetic steel sheet provided with the caulked portion on the magnetic pole center axis that divides the magnet insertion hole into two parts is used to determine the armature reaction of the rotor in the q-axis direction. Apply to a place that does not affect According to the above-described means, the magnetic characteristic degradation due to the processing strain occurs in the bridge portion that requires magnetic saturation in view of the output characteristics of the motor, so that the following operation is achieved. (1) A decrease in the magnetic permeability above the magnets of the rotor core is made very small. (2) By providing the caulking portion in the bridge portion, the magnetic properties (permeability) of this portion are intentionally reduced, and the leakage magnetic flux of the magnet is reduced, so that the input amount of the permanent magnet can be reduced. (3) The caulking process of the bridge portion also causes a hardening action of this portion, and increases the centrifugal force strength.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to examples. FIGS. 1A and 1B show the first and second embodiments of the present invention.
It shows the case with poles and center bridge. In these figures, 1 is a laminated rotor core, 1a is a permanent magnet insertion hole, 2 is a field permanent magnet, and 3 is a swaged portion. The center axis of the magnet magnetic flux is referred to as a d-axis, and a direction magnetically perpendicular to the center axis is referred to as a q-axis. When a load is applied, that is, when the q-axis current Iq flows, the armature reaction magnetic flux Φq flows. In the first embodiment shown in FIG. 1A, the caulking portion 3 is provided on the bridge portion 3 so as not to cover the magnetic path. In the second embodiment shown in FIG. Is provided. FIG. 2 shows a third embodiment in which there are no six poles and no center bridge. In this embodiment, a portion located on the d axis inside the magnet of the rotor core 1 in order to improve the rotor core fastening action. Is provided with a caulking portion 3.

FIG. 3 shows a current phase difference angle-torque characteristic of the inner magnet type motor. Tm is the torque generated by the magnet magnetic flux, Tr is the reluctance torque generated by the armature reaction magnetic flux of the motor, and T is the torque of the inner magnet type motor obtained by adding the magnet torque Tm and the reluctance torque Tr. The current phase difference angle is a phase difference between the induced voltage vector and the current vector of the motor. The + side indicates a case where the current vector is ahead of the induced voltage vector, and the − side indicates a case where the current vector is delayed. It is. Since the reluctance torque Tr has a cycle twice that of the magnet torque Tm, the inner magnet type motor torque T
Also changes according to the current phase difference angle γ, and reaches a maximum point (optimum control point) near the advance angle of 45 °. FIG. 3 shows that if the reluctance torque Tr decreases due to the decrease in magnetic permeability due to magnetostriction, the motor torque T also decreases on the leading side of the current phase difference angle.

[0007]

As described above, according to the present invention, (1) even under load, the permeability of the q-axis magnetic flux path of the rotor core does not decrease and the reluctance torque can be increased, so that the fastening effect of the rotor core can be increased. , The motor output can be improved. (2) Due to the hardening of the bridge portion, the centrifugal force strength of the rotor core is improved, and higher-speed rotation than before becomes possible. (3) Due to the effect of lowering the magnetic permeability of the bridge portion, expensive permanent magnets can be effectively used (reduction of the magnet input), and the cost of the motor can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a rotor core structure showing first and second embodiments of the present invention.

FIG. 2 is a plan view of a rotor core structure showing a third embodiment of the present invention.

FIG. 3 is a diagram showing a generated torque characteristic of an inner magnet type motor.

FIG. 4 is a plan view showing a conventional rotor core structure.

FIG. 5 is a plan view showing another example of a conventional rotor core structure.

6A and 6B are diagrams illustrating the analysis of the magnetic field of the internal magnet type motor, in which FIG. 6A shows a state when no load is applied, and FIG.

[Explanation of symbols]

1 laminated rotor core, 1a magnet insertion hole, 2 field permanent magnet, 3 caulking section, 4 stator, 5 bridge section

Claims (4)

[Claims] In a rotor structure of an internal magnet type motor in which a field permanent magnet is inserted into a magnet insertion hole formed in a rotor core formed by laminating and caulking electromagnetic steel sheets, a position of a caulked portion of the laminated electromagnetic steel sheet is determined by q of the rotor. A rotor structure for an internal magnet type motor, wherein the rotor structure does not affect the armature reaction in the axial direction. 2. A rotor structure for an internal magnet type motor according to claim 1, wherein a bridge portion is provided on a center axis of a magnetic pole that divides the magnet insertion hole into two, and the caulking portion is provided in the bridge portion. . 3. A bridge portion is provided at both ends of the magnet insertion hole, and a hole for preventing leakage of magnetic flux in a circumferential direction of the rotor is provided, and the caulking portion is provided with the bridge portion.
2. A rotor structure for an internal magnet type motor according to claim 1, wherein said rotor structure is provided at a position close to a hole for preventing magnetic flux leakage. 4. The internal magnetic motor according to claim 1, wherein a caulking portion is provided at a yoke portion below the magnet insertion hole of the rotor core, on a center axis of a magnetic pole that bisects the magnet insertion hole. Rotor structure.