KR19980083325A - Permanent magnet embedded rotor structure - Google Patents

Abstract

The present invention relates to a rotor structure of a motor, and more particularly, to a structure for improving the electrical efficiency while ensuring the structural stability of the permanent magnet embedded rotor for placing a permanent magnet inside the rotor, Permanent magnets are embedded in the permanent magnet buried parts including permanent magnet buried parts formed of a plurality of grooves symmetrically to each other in a V-shape consisting of a pair of outwardly about the axis of rotation of the.

Description

Permanent magnet embedded rotor structure

The present invention relates to a rotor structure of a motor, and more particularly, to a structure for improving the electrical efficiency while stabilizing the structure of the permanent magnet buried rotor for placing a permanent magnet inside the rotor.

The motor is an essential electric device for obtaining rotational power, but various motors have been researched and developed. However, according to the propensity of research on small and light-weighted electric and electronic devices applying and adopting these motors, the total volume of electric and electronic devices and Small and light researches were focused on motors, which account for a large proportion of weight.

An alternating current motor, which generates a rotating magnetic field by applying an alternating voltage to the stator, and obtains a rotational force by mutual electromagnetic forces acting between the current flowing through the rotor derived from the rotating field, is a general motor used in many home appliances. However, in these AC motors, various electrical losses due to the current flowing through the rotor have to be taken into consideration, and there are difficulties in miniaturization of the motor due to the difficulties in the process of installing an electric path coil in the core of the motor rotor. .

In addition, in the device requiring the constant torque characteristics, the demand of the DC motor has increased greatly. Although the research and development has been done, the commutator, which is an essential device for the DC motor, must be installed, and the mechanical damage occurring in the commutator should be considered. In addition, the service life did not last long due to the friction between the commutator and the rotating shaft.

Therefore, motors that can install a permanent magnet on the rotor and obtain torque without a commutator have been researched and developed. A representative achievement of this effort is the development of a brushless motor that changes the direction of the magnetic field by changing the current flow electronically instead of the commutator, and installs a permanent magnet on the rotor. By installing a permanent magnet in the rotor, a switched reluctance motor has been developed in which the rotor rotates due to a change in the reluctance of the magnetic field generated by interrupting the energizing current flowing through the permanent magnet of the rotor and the windings of each phase installed in the stator.

Since the brushless motor or the switched reluctance motor is operated at high speed rotation, the permanent magnet rotor structure employed in the brushless motor or the switched reluctance motor should be configured to rotate without electric loss and vibration during the high speed rotation.

Permanent magnet rotors that are commonly used up to now can be divided into permanent magnet external motor and permanent magnet embedded motor.

1 is a perspective view of a rotor of a conventional permanent magnet exterior type.

2 is a cross-sectional view of a rotor of a conventional permanent magnet buried type.

As shown in FIG. 1, the permanent magnet exterior type is an iron core 3 which forms a body by stacking a rotor iron plate 2 made of a thin silicon steel sheet, and bonds an adhesive 4 to an outer circumferential surface of the core. It consists of a permanent magnet 5 of the circular body to be mounted. Reference numeral 1 is a pressing hole for pressing the rotary shaft (not shown) formed in the center of rotation of the rotor.

The rotor of this type of external type is separated from the iron core (3) and the permanent magnet (5) with the loss of adhesion due to the aging change of the adhesive, the failure occurs, and the permanent magnet (5) at high speed rotation of the motor Due to the difference in centrifugal force received by the iron core 3, the phenomenon that the permanent magnet 5 is separated from the iron core 3 may occur.

Therefore, in the high speed rotary motor, the embedded type as shown in FIG. 2 is mainly used.

As shown in Fig. 2, the embedded rotor forms symmetrically formed linear grooves 21 of a predetermined length at a right angle with respect to the radial direction from the center of the rotor iron plate 2.

These straight part grooves 21 form a trough in the longitudinal direction of the rotating shaft when the rotor plate 2 is stacked. The permanent magnet 30 as shown in FIG. 3 is inserted into the trough to generate a magnetic field.

However, such a rotor structure may cause more stress on the end portions 22 in the longitudinal direction of each of the linear grooves 21 than other portions, resulting in damage such as a click. Causes damage to the rotor due to vibration during high speed rotation of the motor.

As a result of various studies and developments to improve this point, Japanese Laid-Open Patent Publication No. 5-236685 (published date: September 10, 1993) is the result of this effort.

The contents described in the above publication are uniform by extending the end of the magnet-embedded groove portion having a predetermined length in a direction perpendicular to the radial direction of the rotor in order to equalize the stress distribution of the embedded rotor by a predetermined length in the radial direction of the rotor. One stress distribution was obtained.

4 is a plan view of an iron plate of a buried rotor with a conventional radially extending groove.

As shown in FIG. 4, the permanent magnet embedded rotor iron plate 2 is symmetrically formed with a magnet buried straight part groove 21 having a predetermined length in a direction perpendicular to the radial direction of the rotor. An end of the 21 forms an extension groove 42 extending outwardly by a predetermined length in the radial direction of the rotor. The extension groove 42 formed as described above is formed in parallel with the extension grooves 42 'of the other magnet embedding linear groove 21. Since the extension grooves 42 and 42 'are disposed in the rotor iron plate 2, the stress distribution becomes uniform, and this stress distribution prevents the vibration of the motor.

However, the arrangement of the extension grooves 42 of the rotor iron plate 2 can uniformly distribute the stress, but since the voids are formed in a direction substantially perpendicular to the flow of the magnetic flux, the magnetic flux is lost, resulting in inefficient energy. It is used.

Fig. 5A is a plan view of the rotor iron core for showing the magnetic flux distribution generated by the stator. FIG. 5B is an enlarged view of portion A of FIG. 5A.

By energizing a coil (not shown) wound around the stator 51, the magnetic flux to be excited flows in the rotor 52 through the gap between the rotor 52 and the stator 51, but the The magnetic flux is interrupted by the air gap of the extension groove 42. As shown in FIG. 5 (b), the extension groove 42 forms a void having a low permeability, so that the magnetic flux is concentrated along the extension groove 42, and the excessive concentration of magnetic flux in a specific region eventually leads to energy loss.

The present invention has been devised in view of the above problems, and by maintaining the magnetic flux flow of the extension groove smoothly to prevent the magnetic flux loss, and to reduce the leakage magnetic flux to prevent energy loss by the same power consumption and magnetic amount The purpose is to obtain a large torque.

1 is a perspective view of a rotor of a conventional permanent magnet exterior type.

2 is a cross-sectional view of a rotor of a conventional permanent magnet buried type.

3 is a perspective view of a permanent magnet embedded in a buried groove shown in FIG.

4 is a plan view of an iron plate of a buried rotor with a conventional radially extending groove.

FIG. 5 (a) is a plan view of a rotor iron core for showing the magnetic flux distribution generated by the stator, and FIG. 5 (b) is an enlarged view of the portion A of FIG. 5 (a).

6 is a plan view of a rotor iron plate used in an embodiment of the present invention.

7 is a magnetic flux distribution diagram passing through the stator and the rotor of the present invention.

8A is a graph measuring torque for an embodiment of the present invention, and FIG. 8B is a graph measuring torque for the motor shown in FIG. 2, which is an example of the prior art.

* Explanation of symbols for the main parts of the drawings *

100: rotor iron plate 120: first permanent magnet buried portion

130: second permanent magnet buried portion 180, 190: permanent magnet

In order to achieve the above object, the present invention is a buried rotor structure for embedding a permanent magnet in the rotor, a permanent consisting of a plurality of grooves in a pair of V (V) shape that is outwardly centered on the rotation axis of the rotor The magnet buried portion is formed symmetrically, and the permanent magnet is buried in the permanent magnet.

In addition, the present invention V-shaped permanent magnet buried portion, the first permanent magnet buried portion formed adjacent to the rotating shaft, and the second permanent magnet formed in parallel to the first permanent magnet buried in the outer direction of the first permanent magnet buried portion It is composed of two buried portions that are magnet buried portions. The present invention also provides that the center connection portion of the first permanent magnet buried portion is formed narrower than other portions to prevent the flow of permanent magnets.

In addition, the length of the buried portion of the second permanent magnet of the present invention is formed smaller than the length of the first permanent magnet buried portion.

Hereinafter, the above objects and features of the present invention will be described in detail with reference to the accompanying drawings.

6 is a plan view of a rotor iron plate used in an embodiment of the present invention. In addition, Figure 7 shows the distribution of the magnetic field when energizing the stator winding according to the present invention, Figure 8 is a magnetic flux distribution generated from the magnet of the rotor in the state of permanent magnet embedded in the permanent magnet buried portion of FIG. Magnetic flux distribution shown.

As shown in FIG. 6, a rotation shaft indentation hole 110 through which a rotating shaft is press-fitted is formed at the center of the rotor iron plate 100, and the rotation shaft indentation hole 110 of the rotor iron plate 100 is centered. Permanent magnet buried parts (120, 130) formed of a plurality of grooves to be mutually symmetric in a V-shaped (V) shape consisting of two outward, the permanent magnet to the permanent magnet buried portion (120, 130) Each of them is buried in correspondence.

The above-described permanent magnet buried parts 120 and 130 may be formed of a first V-shaped first permanent magnet buried part 120 adjacent to a rotating shaft and formed outside the first permanent magnet buried part 120. 1 to form a second permanent magnet buried portion 130 shorter than the length of the permanent magnet buried portion 120, the connection portion 140 located in the center of the first permanent magnet buried portion 120 is inserted into both sides permanent magnet It is formed narrower than the other part so that it does not flow.

At this time, the end portion of the first permanent magnet buried portion 120 is formed to be inclined closer to the outer periphery of the end portion of the first permanent magnet buried portion 121 so that the magnetic flux lines are uniformly distributed.

Reference numeral 150 denotes a fastening hole for forming one iron core by fixing and fastening a rivet welding part or each iron plate for laminating the rotor iron plates 100.

As shown in FIG. 7, when energized sequentially in each phase of the stator winding of the stator 160, the rotor 170 smoothly passes the path of the magnetic flux lines generated from the stator 160 winding and the magnetic flux lines generated from the permanent magnet. Rotor 170 is rotated for the arrangement. However, at this time, when the magnetic flux lines generated by the stator 160 windings flow in the rotor 170, the magnetic flux lines are formed by the first permanent magnet buried parts 120 and the second permanent magnet buried parts 130. Is not distorted and passes through the minimum path.

In addition, the length of the first permanent magnet buried portion 120 is formed larger than the length of the second permanent magnet buried portion 130, the permanent magnet 180 and the permanent magnet (buried in each of the buried portion 120, 130 ( In addition, the magnetic flux lines generated by the permanent magnets 190 are directed toward the air gap by the magnetic flux lines from the permanent magnets 180, thereby preventing the magnetic flux from simply circulating in the rotor. do. Therefore, the flux line generated from the permanent magnet embedded in the rotor increases the effective rate directed to the gap between the rotor and the stator to generate a greater torque.

8A is a graph measuring torque for an embodiment of the present invention, and FIG. 8B is a graph measuring torque for the embodiment of FIG. 2 according to the prior art.

As shown in FIG. 8B, when the machine angle with respect to the rotational direction of the motor is referred to as a reference, the difference between the maximum value and the minimum value of the torque is severe, and a ripple that may cause vibration between the maximum value and the minimum value is formed rapidly. Mechanical vibration and noise are generated, and the average torque per unit stack is approximately 3 kg-cm.

However, the torque of one embodiment of the present invention measured at the same power consumption and magnetic quantity as in FIG. 8B has a very small ripple formation as shown in FIG. 8A, and the difference between the maximum value and the minimum value is not large, so vibration and noise are not significant. Can be reduced. In addition, the average torque per unit stacking is approximately 8kg-cm, it is possible to obtain a torque more than twice the conventional average torque. Therefore, high output can be obtained even at small power consumption.

According to the object and configuration of the present invention as described above, the rotor of the present invention creates a smooth flow of the magnetic flux, and when a constant voltage is applied, it shows a better efficiency than the rotor of the other structure, the magnetic flux with a uniform magnetic flux distribution This exhibits an effect of suppressing vibration more than when it is biased. In addition, high torque can be obtained at the same magnetic amount, and energy can be efficiently used.

Claims (4)

In the embedded rotor structure in which the permanent magnet is embedded in the rotor, the permanent magnet is embedded in the permanent magnet buried portions formed of a plurality of grooves symmetrically with each other in a V-shape that is outwardly centered on the rotation axis of the rotor. Permanent magnet embedded rotor structure, characterized in that for embedding. The permanent magnet buried type rotor according to claim 1, wherein the permanent magnet buried portion comprises a first permanent magnet buried portion formed adjacent to the rotating shaft, and a second permanent magnet buried portion formed outside the first permanent magnet buried portion. rescue. The permanent magnet buried rotor structure according to claim 2, wherein the center connection portion of the first permanent magnet buried portion is formed to be narrower than other portions to prevent the flow of the permanent magnet. 3. The permanent magnet buried rotor structure according to claim 1 or 2, wherein the length of the first permanent magnet buried portion is longer than the length of the second permanent magnet buried portions.