KR100409178B1 - Rotor of Interior Permanent Magnet Type - Google Patents

Abstract

The present invention relates to a new type of permanent magnet embedded rotor capable of maximizing air gap flux while having high dimensional stability and simple manufacturing process, low production cost.

The present invention is made of a non-magnetic material and has the same shape and symmetrical structure, respectively, and has a disc shaped upper and lower cover, and both ends are supported on the outer circumferential portion of the same circumference of the upper and lower covers, respectively. A plurality of yoke blocks corresponding to the plurality of yoke blocks, a plurality of plate-shaped permanent magnets inserted between the plurality of yoke blocks and corresponding to magnetic poles supported by the yoke blocks and the upper and lower covers, and formed at the center of the upper and lower covers. And a rotating shaft coupled to and supported by the through hole.

Description

Rotor of Interior Permanent Magnet Type

The present invention relates to a permanent magnet embedded rotor, and more particularly to a new type of permanent magnet embedded rotor capable of maximizing the dimensional stability and the manufacturing process is simple, low production cost and maximize the air gap flux.

In general, a radial rotor structure used in a brushless DC motor is a cylindrical magnet 1 formed in an annular shape as shown in FIGS. 1 and 2 or a C-shaped magnet 1a-1h including a plurality of segments. Is bonded to the outer circumference of the rotor yoke (2). The cylindrical magnet 1 is integrally formed with a plurality of N-pole and S-pole magnets alternately formed in a split magnetization manner, and the member No. 3 is an axis.

This structure is not a big problem in general small electric motors such as home appliances, but in the case of medium and large electric motors, the magnet of the split piece magnet by centrifugal force at a predetermined rotation speed due to the increase in the magnet weight due to the increase of the rotor radius increases. A detachment and breakage countermeasure was required, and as an alternative, a permanent magnet embedded rotor structure as shown in FIGS. 3 and 4 has been proposed to expand its application.

That is, the conventional permanent magnet embedded rotor shown in FIG. 3 includes a plurality of plate-shaped permanent magnets 11 having a plurality of embedded grooves 14 formed along the circumferential direction of the rotor yoke 12 with respect to the rotation axis 13. 4, the rotor shown in FIG. 4 has a plurality of plate-shaped permanent magnets 21 formed with a plurality of recessed grooves 24 formed along the axial direction on the outer side of the rotor yoke 22 with respect to the rotation axis 23. ) Has a structure embedded in The rotor yokes 12 and 22 are formed by punching and forming an iron yoke material (a silicon steel sheet and a thin iron sheet) using a press.

In FIGS. 3 and 4, reference numerals 15 and 25 denote stator yokes and 16 and 26 denote stator coils.

However, in the case of the conventional permanent magnet embedded rotor, there are other problems, such as inefficiency due to inefficient magnet use and reduction in manufacturing cost due to difficulty in manufacturing a mold due to the reduction of effective void flux caused by leakage magnetic flux.

In general, the motor has an electromagnetic coupling relationship, the output characteristics are determined as in Equation 1 below.

T = i × B × L × r

Where T = torque, I = current, B = magnetic flux density = Φg (void magnetic flux), L = conductor length, r = rotation radius.

It can be seen that the torque (T) for determining the force of the motor in Equation 1 is proportional to the void magnetic flux (Φg), and in order to increase the efficiency of using magnetic energy for the permanent magnet of the same volume, the leakage flux is minimized and the economical efficiency is improved. This requires a rotor structure.

In the following permanent magnet embedded rotor structure shown in FIGS. 3 and 4, the relationship between the pore flux contributing to the output of the motor and the leakage flux not contributing to the output of the motor is analyzed.

Φm = Φg + Φi + Φo

Where? G = void magnetic flux,? I = yoke inner diameter leakage flux, and? O = yoke outer diameter leakage flux.

That is, the total magnetic flux density (Φm) generated in the magnet is divided into the air gap magnetic flux (Φg), the yoke inner diameter leakage flux (Φi) and the yoke outer diameter leakage flux (Φo), and the core of the motor design is the air flux magnetic flux (Φg) It can be said to minimize the leakage flux to maximize the.

3 and 4, the magnetic flux distribution may be displayed as an equivalent circuit, as shown in FIG. 5. In the equivalent circuit of FIG. 5, since the magnetomotive force Fm is proportional to the product of the magnetic flux density and the magnetoresistance, Equation 3 below is established.

Fm = Φi × Ri

= Φo × Ro

= Φg × Rg

Where Ri and Ro are equivalent magnetic resistances of the inner / outer diameters of the yoke and Rg is the magnetic resistance of the voids. In addition, the magnetoresistance R is represented by the following equation (4).

ℓ: length of vine

A: cross-sectional area

μ: Permeability (μ = μ _o × μ _r )

μ _o : Permeability in air (constant)

μ _r : specific permeability

It can be seen from Equation 4 that the leakage magnetic flux can be minimized only by increasing the magnetoresistance R at a constant magnetomotive force Fm.

In general, the specific magnetic permeability (μ _r) of iron-based iron used as a magnet yoke is 1000 times higher than that of air, so that the magnetic resistance (Ri, Ro) of iron-based yolk is almost negligible compared to the magnetic resistance (Rg) of the air gap. Value. As a result, in Fig. 3, Ri = Ro << Rg, and in Fig. 4, Ri <Ro << Rg, which shows that the leakage magnetic flux is inevitably larger than the effective void density.

In other words, in FIG. 3, Φg << Φi = Φo, and in FIG. 4, Φg << Φo <Φi. That is, the void magnetic flux Φg is relatively smaller than the leakage magnetic fluxes Φo and Φi, so that the magnetic energy utilization rate of the same permanent magnet is lowered, which is uneconomical.

In addition, the loss due to the magnetic flux path inside the yoke (leakage magnetic flux) is greater than the air gap magnetic flux.

For example, in the structure of FIGS. 3 and 4, when a magnet having a cross section of 10 mm x 3 mm is used, when t = 0.5 mm, both sides 1-2 mm are lost due to the influence of leakage magnetic flux, so that only 50-60% of the magnetomotive force is substantially reduced. It is uneconomical to contribute to the output power of, and as the number of magnetic poles is increased to increase the torque, the loss of leakage flux in the magnetic flux path increases, resulting in a decrease in the efficiency of the permanent magnet embedded magnet.

In addition, in the conventional rotor illustrated in FIG. 3, the yoke 12 has a loss of leakage flux as the width t between the embedding groove 14 and the embedding groove 14 for embedding the magnet 11 is minimized. In this case, the strength is lowered. Therefore, it is necessary to maintain at least t = 0.5 mm in consideration of safety factor and difficulty in mold making.

Furthermore, in the conventional rotor shown in FIG. 4, the yoke 22 has less loss as the connection portion between the embedding groove 24 and the rotating shaft 23 for embedding the magnet 21 is reduced, but in this case, high speed The phenomenon that the connection part is broken by centrifugal force during rotation may occur.

Therefore, the present invention has been made in view of the problems of the prior art, and its object is to adopt a structure that maximizes the magnetic resistance to leakage flux in the magnetic flux path by switching to an air gap instead of the iron-based magnetic flux path It is to provide a new type of permanent magnet embedded rotor that can improve the motor output by minimizing the leakage flux and maximizing the effective air gap flux that contributes to the motor output.

In addition, another object of the present invention is to provide a permanent magnet-embedded rotor that can minimize the weight of the entire rotor to realize a low inertia moment to improve the maneuverability and at the same time reduce the cost of high material utilization.

In addition, another object of the present invention is to form the yoke by the iron powder metallurgy method, it is excellent in dimensional stability, corrosion resistance, and symmetrical structure to reduce the production cost of the mold, simplifying the assembly process, uniformity To provide a permanent magnet embedded rotor that can be minimized.

1 is a cross-sectional view showing a rotor structure made of an integrated magnet used in a conventional brushless DC motor;

Figure 2 is a cross-sectional view showing a rotor structure consisting of a split magnet used in a conventional brushless DC motor,

3 is a cross-sectional view showing a typical permanent magnet embedded rotor structure,

4 is a cross-sectional view showing another conventional representative permanent magnet embedded rotor structure,

5 is an equivalent circuit for magnetic flux distribution in the conventional permanent magnet embedded rotor structure shown in FIGS. 3 and 4;

Figures 6a to 6c are respectively a plan view of the upper cover for the rotor of the first preferred embodiment according to the present invention with the top cover removed, line VI-VI cross-sectional view and exploded perspective view of Figure 6a,

7A to 7C are respectively a plan view of a lower yoke for the second preferred embodiment rotor according to the present invention, a sectional view taken along line X-ray of Fig. 7A, and an exploded perspective view;

8A to 8C are respectively a plan view of a lower yoke for a third preferred embodiment rotor according to the present invention, a sectional view taken along line X-ray of Fig. 8A, and an exploded perspective view;

9A to 9D are respectively a plan view, a sectional view taken along line X-ray of Fig. 9A, an exploded perspective view, and an assembled perspective view of a rotor of a fourth preferred embodiment according to the present invention.

* Explanation of Signs of Major Parts of Drawings *

10; Stator 30,40,50,60; Rotor

31,34; Cover 31a, 43a; Body

31b, 31e, 34b, 34e, 41e, 44e, 41f, 44f, 51e, 54e, 61g, 64g; Through hole

31c, 34c; Guide portion 32a; Block body

31d, 34d, 41d, 44d, 51d, 54d, 61e, 64e; boss

32,51a, 54a, 61a-61d, 64a-64d; York block

32b, 32c; Engaging projections 32d, 51b, 51c, 54b, 54c, 66, 67; spin

33,43,54,63a-63h; Permanent magnets 35,45,55,65; Axis of rotation

41,44,51,54,61,64; Upper and lower yokes 41a, 44a; Inner tube

41b, 44b; Outer cylinder 41c, 44c; Connection

41g, 44g, 51g, 54g; Rim 41h, 44h; Incision

61f, 64f; Connecting plate

In order to achieve the above object, the present invention is made of a non-magnetic material and has a structure that is the same shape and symmetrical, respectively, and has a disk-shaped upper and lower cover, and the same circumferential shape of the upper and lower cover, respectively. A plurality of yoke blocks supported at both ends of the outer periphery and corresponding to the number of magnetic poles, a plurality of plate-shaped permanent magnets inserted between the plurality of yoke blocks and corresponding to the number of magnetic poles supported by the yoke block and the upper and lower covers; It provides a permanent magnet embedded rotor, characterized in that consisting of a rotating shaft coupled to and supported by a through hole formed in the central portion of the upper and lower covers.

According to another feature of the invention, the present invention has a top and bottom yoke having a polygonal inner cylinder and the outer cylinder corresponding to the number of magnetic poles in the vertical symmetric structure and having a plurality of through holes formed in the longitudinal direction between the inner cylinder and the outer cylinder; A plurality of plate-shaped permanent magnets inserted through the through-holes of the upper and lower yokes to correspond to the number of magnetic poles supported between the inner and outer cylinders, and a rotating shaft coupled to and supported by the through-holes of the bosses formed in the centers of the upper and lower yokes. The outer cylinder is formed by artificially incised portions corresponding to the space between the permanent magnets, thereby maximizing the air gap magnetic flux (Φg) by forming an artificial air gap in the magnetic path of both ends of the permanent magnets Provide a permanent magnet embedded rotor.

According to another feature of the invention, the present invention is a top and bottom yoke having a plurality of yoke blocks divided in correspondence to the number of magnetic poles in the vertical symmetry structure and the boss formed extending from the yoke block to the center portion, and the upper and It consists of a plurality of plate-shaped permanent magnets corresponding to the number of magnetic poles supported between the plurality of yoke blocks of the lower yoke, and a rotating shaft coupled to and supported by the through-holes of the boss of the upper and lower yoke, the magnetic of both ends of the permanent magnet By providing an artificial air gap in the path provides a permanent magnet embedded rotor, characterized in that to maximize the air gap magnetic flux (Φg).

According to another feature of the present invention, the present invention has the same structure as each other, and each of the first and second yoke blocks of the number of magnetic poles is arranged in an arc-shaped shape and positioned at the center by first and second connecting means. First and second yokes connected to the two bosses and coupled to each other to form a rotor yoke, a plate-shaped permanent magnet supported between the respective yoke blocks of the first and second yokes and corresponding to the number of magnetic poles; It consists of a rotating shaft of the rotor coupled to and supported by the through holes of the boss of the first and second yoke, by maximizing the void flux (Φg) by forming an artificial air gap in the magnetic path of both ends of the permanent magnet A permanent magnet embedded rotor is provided.

As described above, the present invention employs a structure in which the magnetic resistance to leakage magnetic flux in the magnetic flux path is maximized by switching to an air gap instead of the iron magnetic flux path, thereby minimizing leakage magnetic flux and contributing to the output of the motor. The motor output can be improved by maximizing the effective air gap flux.

(Example)

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The present invention is a method for minimizing leakage flux (Φo, Φi) and maximizing void flux (Φg) as a method to improve the problems of the prior art as the air gap (space) instead of the iron magnetic flux path By switching, the structure that maximizes the magnetoresistance (Ri, Ro) to the leakage magnetic flux in the magnetic flux path is adopted.

6A to 6C are respectively a plan view of the upper cover of the rotor of the first preferred embodiment according to the present invention with the top cover removed, a sectional view taken along line VI-VI of FIG. 6A, and an exploded perspective view.

The rotor 30 of the first embodiment according to the present invention is largely supported at both ends of the upper and lower covers 31 and 34, and on the outer circumference of the same circumference of the upper and lower covers 31 and 34, respectively. A plurality of yoke blocks 32 corresponding to the plurality of yoke blocks and a plurality of yoke blocks 32 inserted between the plurality of yoke blocks 32 and corresponding to the number of magnetic poles supported by the yoke blocks 32 and the upper and lower covers 31 and 34. It consists of a plate-shaped permanent magnet 33 and a rotating shaft 35 of the rotor coupled to and supported by the through holes 31e and 34e formed at the centers of the upper and lower covers 31 and 34.

The plurality of yoke blocks 32 each have a circular arc-shaped block body 32a having a predetermined arc angle and a predetermined length set according to the number of magnetic poles, and protrude on upper and lower surfaces of the block body 32a. It consists of at least one pair of coupling protrusions 32b and 32c. At both ends of the outer circumferential portion of each yoke block 32, projections 32d are formed along the longitudinal direction to prevent the plate-shaped permanent magnet 33 supported between the yoke blocks 32 from being separated by centrifugal force. It is desirable to have. The yoke block 32 is preferably molded using an iron (Fe) -based powder metallurgy method.

For example, the upper and lower covers 31 and 34 have the same shape and symmetrical structure and are disposed on the upper and lower sides, respectively, to correspond to the number of magnetic poles in the upper and lower portions so as to support the yoke blocks 32 at regular intervals. Eight through holes 31b and 34b are formed along the outer circumferential portion thereof, and the disc-shaped bodies 31a and 34a into which the engaging projections 32b and 32c of the yoke block 32 are inserted, respectively, and each of the bodies 31a and 34a. The inner periphery of the plurality of yoke blocks 32 and the permanent magnets 33 supported on the inside are guided to the guide parts 31c and 34c protrudingly positioned at the same distance from the shaft, and the through holes 31e and 34e in the center part. It is composed of bosses (31d, 34d) for supporting the rotating shaft 35 is supported, the body body (31a, 34a), the guide portion (31c, 34c), the boss (31d, 34d) is a non-magnetic Al It is molded integrally by the die casting method using.

In this case, in the rotor 30 according to the first embodiment of the present invention, a magnetic path is formed between the stator 10 and the stator 10 in the same manner as the conventional example shown in FIG. The corresponding plate-shaped permanent magnet 33 has the same polarity on both sides with respect to each yoke block 32 such that the yoke blocks 32 are alternately set to the N pole and the S pole.

The rotor 30 according to the first embodiment assembled in the above structure has a rotor yoke to form an artificial air gap (space) in the magnetic path of each end of the permanent magnet 33 embedded between the yoke blocks 32. Was formed by dividing.

As a result, the yoke inner and outer diameter leakage fluxes Φ i and Φ o are formed through the air gap, so that the magnetoresistance Ri and Ro of the yoke inner and outer diameter parts are formed on the magnetic path between the rotor yoke and the stator 10. It becomes relatively larger than the pore magnetoresistance Rg, so that the pore magnetic flux Φ g also becomes larger than the leakage magnetic flux phi i and phi o.

As a result, Φo = Φi << Φg, so that the void flux (Φg) can be maximized.

In addition, the rotor 30 of the first embodiment employs only the minimum structure necessary for the upper and lower covers 31 and 34 to support the yoke block 32 and the permanent magnet 33 in connection with the rotation shaft 35. It is designed to remove the space part of the center. As a result, the weight of the entire rotor 30 is minimized to realize a low moment of inertia, thereby improving maneuverability.

In the first embodiment, since the yoke is formed by the iron powder metallurgy method, the dimensional stability is superior to the product formed by the lamination press method (the dimensional unevenness occurs due to the burr when it is punched out), and the iron powder metallurgy is also used. As it is a product, when heat treatment, corrosion is less than that of laminated press product. Yoke molding by the iron powder metallurgy method can be produced at a relatively very low cost of about 10-20% of the laminated press die ratio.

7A to 7C show, respectively, a plan view of the lower yoke of the preferred embodiment rotor according to the present invention, the sectional view taken along line X-ray of Fig. 7A, and an exploded perspective view.

The rotor 40 of the second embodiment has an upper and lower yoke 41 and 44 having a plurality of through-holes 41f corresponding to the number of magnetic poles and polygonal inner and outer cylinders having a large symmetrical structure, and the upper and lower portions. A plurality of plate-shaped permanent magnets 43 corresponding to the number of magnetic poles supported by the yokes 41 and 44, and through holes 41e of the bosses 41d and 44d formed at the center of the upper and lower yokes 41 and 44, respectively. And a rotating shaft 45 of the rotor that is coupled to and supported by 44e.

The upper and lower yokes 41 and 44 are respectively spaced apart from the polygons corresponding to the number of magnetic poles, for example, octagonal inner cylinders 41a and 44a and eight outward surfaces of the inner cylinders 41a and 44a. Outer cylinders 41b and 44b having opposite and parallel inner and peripheral surfaces and curved outer circumferential surfaces, and the inner and outer cylinders 41a and 44a and the outer and outer cylinders 41b and 44b, respectively, are connected along the axial direction with a channel corresponding to the number of magnetic poles. A plurality of connecting portions 41c and 44c forming a plurality of through holes 41f and 44f for magnet insertion, and bosses 41d and 44d for supporting the plurality of connecting portions 41c and 44c and the rotating shaft 45, respectively. It is composed of a plurality of rims 41g and 44g extending in the axial direction from the plurality of connecting portions 41c and 44c for connection.

The yoke blocks 41 and 44 are preferably molded using an iron (Fe) -based powder metallurgy method.

The plate-shaped permanent magnet 43 corresponding to the magnetic pole water is inserted and fixed between the inner cylinder 41a and the outer cylinder 44a through the plurality of through holes 41f and 44f of the assembled upper and lower yokes 41 and 44. In this case, in the rotor 40 according to the second embodiment of the present invention, each surface of the polygonal inner cylinders 41a and 44a to form a magnetic path between the stator 10 in the same manner as the conventional example shown in FIG. The permanent magnets 43 inserted so as to be set to the alternating polarity are arranged such that the pole faces of the N pole and the S pole are alternately arranged. The length of the plate-shaped permanent magnet 43 is set equal to the sum of the lengths of the upper and lower yokes 41 and 44.

The rotor 40 according to the second embodiment of the above-described structure includes a permanent magnet adjacent to each of the permanent magnets 43 embedded in the outer cylinders 41b and 44b of the upper and lower yokes 41 and 44. By connecting the portions of the outer cylinder between the outer cylinders 43, i.e., the portions corresponding to the connecting portions 41c and 44c, by artificially cutting them to form the cutout portions 41h and 44h, as a result, in the magnetic paths at both ends of the permanent magnet 43. An artificial air gap was formed.

As a result, the yoke inner and outer diameter leakage fluxes Φ i and Φ o are formed through the air gap, so that the magnetoresistance Ri and Ro of the yoke inner and outer diameter parts are formed on the magnetic path between the rotor yoke and the stator 10. It becomes relatively larger than the pore magnetoresistance Rg, so that the pore magnetic flux Φ g also becomes larger than the leakage magnetic flux phi i and phi o.

As a result, Φo = Φi << Φg, so that the void flux (Φg) can be maximized.

In addition, the rotor 40 of the second embodiment employs only the minimum structure necessary for the upper and lower yokes 41 and 44 to support the permanent magnets 43, and the plurality of connecting portions 41c and 44c and the rim 41g. The inner spaces 41a and 44a and the outer cylinders 41b and 44b and the bosses 41d and 44d are connected to each other so that the space portion of the center portion is removed. As a result, the weight of the entire rotor 40 is minimized to realize a low moment of inertia, thereby improving maneuverability.

8A to 8C are respectively a plan view of the lower yoke for the third preferred embodiment rotor according to the present invention, a sectional view taken along line X-ray of Fig. 8A, and an exploded perspective view.

The rotor 50 of the third embodiment has upper and lower yokes 51 and 54 having a plurality of yoke blocks 51a and 54a divided in correspondence with the number of magnetic poles in a substantially vertically symmetrical structure. A plurality of plate-shaped permanent magnets 53 corresponding to the number of magnetic poles supported between the plurality of yoke blocks 51a and 54a of the lower yokes 51 and 54, and a central portion of the upper and lower yokes 51 and 54; It consists of the rotating shaft 55 of the rotor which is coupled to and supported by the through-holes 51e and 54e of the bosses 51d and 54d.

The upper and lower yokes 51 and 54 are arc shaped large yoke blocks 51a and 54a each having a predetermined arc angle and a predetermined length set according to the number of magnetic poles, and the plurality of yoke blocks 51a. And a plurality of rims 51g and 54g extending along the axial direction from the plurality of yoke blocks 51a and 54a to connect the bosses 54d and 54d for supporting the shaft 54a and the rotary shaft 55.

Projections 51b, 51c: 54b at both ends of the outer circumferential portion of each of the yoke blocks 51a and 54a to prevent the plate-shaped permanent magnet 53 supported between the yoke blocks 51a and 54a from being separated by centrifugal force. (54c) is preferably formed along the longitudinal direction. The upper and lower yokes 51 and 54 are preferably molded using an iron (Fe) based powder metallurgy method.

The plate-shaped permanent magnet 53 corresponding to the magnetic pole number is inserted and fixed in the space between the plurality of yoke blocks 51a and 54a of the assembled upper and lower yokes 51 and 54, in which case the third embodiment of the present invention In the rotor 50 according to the example, the permanent magnet 53 is disposed to form a magnetic path between the stator 10 in the same manner as in the first embodiment. That is, the plate-shaped permanent magnet 53 corresponding to the magnetic pole number has a magnet surface of the same polarity on both sides with respect to each of the yoke blocks 51a and 54a so that the yoke blocks 51a and 54a are alternately set to the N pole and the S pole. Is placed. The length of the plate-shaped permanent magnet 53 is set equal to the sum of the lengths of the upper and lower yokes 51 and 54.

The rotor 50 according to the third embodiment assembled with the above structure forms an artificial air gap (space) in the magnetic path of the end of each permanent magnet 53 embedded between the plurality of yoke blocks 51a and 54a. The rotor yoke was formed by dividing the rotor yoke.

As a result, the yoke inner and outer diameter leakage fluxes Φ i and Φ o are formed through the air gap, so that the magnetoresistance Ri and Ro of the yoke inner and outer diameter parts are formed on the magnetic path between the rotor yoke and the stator 10. It becomes relatively larger than the pore magnetoresistance Rg, so that the pore magnetic flux Φg is also relatively larger than the leakage magnetic flux Φi and Φo.

As a result, Φo = Φi << Φg, so that the void flux (Φg) can be maximized.

In addition, the rotor 50 of the third embodiment adopts only the minimum structure necessary for the upper and lower yokes 51 and 54 to support the permanent magnets 53, similar to the first and second embodiments. The plurality of yoke blocks 51a and 54a and the bosses 51d and 54d are connected to each other through a plurality of rims 51g and 54g in a shape to remove the central portion. As a result, the weight of the entire rotor 50 is minimized to realize a low moment of inertia, thereby improving maneuverability.

In the second and third embodiments, a structure in which a plurality of rims 41g, 44g; 51g, 54g are interconnected with the bosses 41d, 44d; 51d, 54d in the center portion is illustrated. It is also possible to use disc shaped plates.

9A to 9D are respectively a plan view, a sectional view taken along line X-ray of Fig. 9A, an exploded perspective view, and an assembled perspective view of a rotor of a fourth preferred embodiment according to the present invention.

The rotor 50 of the fourth embodiment has a vertically shifted symmetrical structure unlike the vertically symmetrical coupling type of the second and third embodiments. The structural description of the fourth embodiment will be described taking an example of having eight stimuli as shown. The rotor 50 has the same structure, but the first and second yoke (61, 64) and each of the four yoke blocks (61a-61d, 64a-64d) are shifted to each other to form a rotor yoke, and Eight plate-shaped permanent magnets 63a-63h supported between the eight yoke blocks 61a-61d and 64a-64d of the first and second yokes 61 and 64 and the first and second yokes 61. And a rotating shaft 65 of the rotor that is coupled to and supported by the through-holes 61g and 64g of the bosses 61e and 64e formed at the center of the 64.

The first and second yokes 61 and 64 each have a circular arc-shaped half magnetic pole number having a predetermined arc angle and a predetermined length set according to the number of magnetic poles, that is, four yoke blocks 61a to 61d. And 64a-64d, and disk connecting plates 61f and 64f for connecting the bosses 61e and 64e with the upper or lower side of the four yoke blocks 61a-61d and 64a-64d. In this case, the connection structure for connecting the yoke blocks 61a-61d and 64a-64d to the bosses 61e and 64e may be formed in various shapes / structures in addition to the disk type.

Further, plate-shaped permanent magnets 63a-63h supported between the yoke blocks 61a-61d and 64a-64d are separated by centrifugal force at both ends of the outer circumferential portion of each of the yoke blocks 61a-61d and 64a-64d. It is preferable that the projections 66 and 67 for preventing them from being formed are formed along the longitudinal direction. The yokes 61 and 64 are preferably molded using an iron (Fe) -based powder metallurgy method.

The embedded permanent magnets 63a-63h corresponding to the magnetic pole water are inserted into and fixed in the space between the plurality of yoke blocks 61a-61d and 64a-64d of the assembled first and second yokes 61 and 64. In this case, in the rotor 60 according to the fourth embodiment of the present invention, the permanent magnets 63a-63h are disposed to form a magnetic path between the stator 10 in the same manner as in the first or third embodiment. . In other words, the plate-shaped permanent magnets 63a-64h corresponding to the magnetic pole number are each yoke block 61a- such that the yoke blocks 61a, 64a, 61b, ... 61d, 64d are alternately set to the N pole and the S pole. 61d, 64a-64d) magnet faces of the same polarity are arranged on both sides.

The rotor 50 according to the fourth embodiment assembled with the above structure is located in the magnetic path of the end portions of the permanent magnets 63a-63h embedded between the yoke blocks 61a-61d and 64a-64d, as shown in FIG. 9D. The rotor yoke was formed by dividing to form an artificial air gap (space).

As a result, the yoke inner and outer diameter leakage fluxes Φ i and Φ o are formed through the air gap, so that the magnetoresistance Ri and Ro of the yoke inner and outer diameter parts are formed on the magnetic path between the rotor yoke and the stator 10. It becomes relatively larger than the pore magnetoresistance Rg, so that the pore magnetic flux Φ g also becomes larger than the leakage magnetic flux phi i and phi o.

As a result, Φo = Φi << Φg, so that the void flux (Φg) can be maximized.

In addition, the rotor 60 of the fourth embodiment has only the minimum structure necessary for the first and second yokes 61 and 64 to support the permanent magnets 63a to 63h, similarly to the first to third embodiments. It is designed to have a structure in which the space portion in the center portion is removed by connecting the yoke blocks 61a-61d, 64a-64d and the bosses 61e, 64e through the disk-shaped connecting plates 61f, 64f. As a result, the weight of the entire rotor 60 is minimized to realize a low moment of inertia, thereby improving maneuverability.

Furthermore, the rotors 40-60 of the second to fourth embodiments described above are also molded by the iron-based powder metallurgy method in the same manner as the first embodiment, so that the products are formed by the lamination press method. Dimension dimensional non-uniformity), and because it is an iron-based powder metallurgy product, when the heat treatment is less corrosion than the laminated press product.

In addition, the yoke molding by the iron-based powder metallurgy method can be manufactured at a relatively very low cost of about 10-20% of the laminated press mold ratio, the product competitiveness is very high. In addition, even in a multi-pole structure, the effective void flux can be maximized with the minimum permanent magnet compared to the permanent magnet rotor by minimizing the leakage flux (Φ i, Φ o).

In addition, the rotor structure employing a separate yoke can reduce costs due to high material utilization.

In addition, since the first to fourth embodiments use a symmetrical structure, it is possible to minimize the product cost by reducing the mold manufacturing cost, simplifying the assembly process, and homogenizing.

In the above-described embodiment, the case where the number of magnetic poles is 8 poles has been described as an example. However, the present invention is not limited thereto and may be modified as necessary. The present invention may be applied to both a permanent magnet motor such as a DC servo motor and an AC servo motor. .

As described above, the present invention employs a structure in which the magnetic resistance to leakage magnetic flux in the magnetic flux path is maximized by switching to an air gap instead of the iron magnetic flux path, thereby minimizing leakage magnetic flux and contributing to the output of the motor. The motor output can be improved by maximizing the effective air gap flux.

In addition, by minimizing the weight of the entire rotor to realize a low moment of inertia, it is possible to improve the maneuverability and to reduce the cost of high material utilization.

Furthermore, since the rotor is molded by iron powder metallurgy, it has excellent dimensional stability, corrosion resistance, and symmetrical structure, so it is possible to minimize product cost by reducing mold manufacturing cost, simplifying assembly process, and uniformity. .

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments and is not limited to the spirit of the present invention. Various changes and modifications can be made by those who have

Claims (13)

A disk-shaped upper and lower cover formed of a nonmagnetic material and having the same shape and symmetrical structure, respectively; A plurality of yoke blocks each having both ends supported on the same circumferential outer periphery of the upper and lower covers and corresponding to the number of magnetic poles; A plurality of plate-shaped permanent magnets inserted between the plurality of yoke blocks and corresponding to magnetic poles supported by the yoke blocks and the upper and lower covers; Permanent magnet embedded rotor, characterized in that consisting of a rotating shaft coupled to and supported by the through-holes formed in the central portion of the upper and lower covers. According to claim 1, wherein the plurality of yoke blocks each arc-shaped block body having a predetermined arc angle and a predetermined length set in accordance with the number of magnetic poles, and protrudes on the upper and lower surfaces of the block body And a pair of coupling protrusions coupled to the lower cover. The yoke block of claim 2, wherein the upper and lower covers each include a plurality of through holes corresponding to the magnetic poles along the outer circumference of the upper and lower portions so as to support the plurality of yoke blocks at regular intervals, respectively. A disc-shaped body, a plurality of yoke blocks supported inside each of the bodies, and a disc-shaped guide portion protruding to be positioned at the same distance from the shaft, and a rotating shaft supported by the through-hole of the center. Consisting of a boss for forming, permanent magnet embedded rotor, characterized in that formed integrally by the die-casting method. According to claim 1, The plurality of permanent magnets are the same polarity is disposed on both sides for each yoke block so that a plurality of yoke blocks are alternately set to the N pole and the S pole, The rotor is formed by artificial air gap in the magnetic path of each end of the permanent magnet embedded between the yoke blocks by the split formation of the rotor yoke, the void magnetic flux (Φg) is formed relatively larger than the leakage magnetic flux (Φi, Φo) Permanent magnet embedded rotor, characterized in that. Upper and lower yokes having a polygonal inner and outer cylinders corresponding to the number of magnetic poles in a vertical symmetric structure and having a plurality of through holes formed in the longitudinal direction between the inner and outer cylinders; A plurality of plate-shaped permanent magnets inserted through the through holes of the upper and lower yokes and corresponding to the number of magnetic poles supported between the inner and outer cylinders; Is composed of a rotating shaft coupled to and supported by the through hole of the boss formed in the center of the upper and lower yoke, The outer cylinder is permanently embedded, characterized in that the portion corresponding to the space between the permanent magnets are artificially incision, thereby maximizing the void flux (Φg) by forming an artificial air gap in the magnetic path of both ends of the permanent magnet. Mold rotor. Upper and lower yokes having a plurality of yoke blocks divided in correspondence to the number of magnetic poles in the vertical symmetry structure and a boss formed extending from the yoke blocks to the center portion, A plurality of plate-shaped permanent magnets corresponding to the number of magnetic poles supported between the plurality of yoke blocks of the upper and lower yokes, Is composed of a rotating shaft coupled to and supported by the through holes of the boss of the upper and lower yoke, Permanent magnet embedded rotor, characterized in that to maximize the air gap magnetic flux (Φg) by forming an artificial air gap in the magnetic path of both ends of the permanent magnet. 6. The upper and lower yokes respectively face the inner cylinder of the polygon corresponding to the number of magnetic poles and face the outer surface of the inner cylinder at a predetermined distance to form an artificial air gap in the magnetic paths at both ends of the permanent magnet. A magnet is inserted into the outer cylinder having an inner circumferential surface and an outer circumferential surface of the curved surface, and a portion corresponding to the space portion between the permanent magnets is artificially cut, and connected along the axial direction with a channel corresponding to the number of magnetic poles above or below the inner cylinder and the outer cylinder. And a plurality of connecting portions forming a plurality of through holes, a boss for supporting the rotating shaft, and a plurality of rims for connecting the plurality of connecting portions and the boss, Permanent magnets embedded in each of the polygonal inner cylinder to be alternately inverted polarity of the permanent magnet embedded rotor, characterized in that the pole surface of the N pole and the S pole is arranged inverted. 7. The plurality of yoke blocks according to claim 6, wherein the upper and lower yokes each include a plurality of arc-shaped yoke blocks each having a predetermined arc angle set according to the number of magnetic poles, a boss for supporting the rotating shaft, and the plurality of yoke blocks. Permanent magnet embedded rotor, characterized in that consisting of a plurality of rims for connecting the boss. 7. The permanent magnet embedded rotor according to claim 6, wherein the permanent magnet is provided with magnet faces of the same polarity on both sides of each yoke block such that the yoke blocks are alternately set to the N pole and the S pole. 7. The permanent magnet embedded rotor according to claim 5 or 6, wherein the upper and lower yokes are formed using an iron (Fe) -based powder metallurgy method. The yoke blocks of the number of magnetic poles each have the same structure and are arranged in an arc-shaped shape and connected to the first and second bosses located in the center by the first and second connecting means, and are coupled to each other by the rotor. First and second yokes forming the yoke, A plate-shaped permanent magnet supported between each yoke block of the first and second yokes and corresponding to the number of magnetic poles; It consists of a rotating shaft of the rotor coupled to and supported by the through holes of the boss of the first and second yoke, Permanent magnet embedded rotor, characterized in that to maximize the air gap magnetic flux (Φg) by forming an artificial air gap in the magnetic path of both ends of the permanent magnet. 12. The permanent magnet embedded rotor according to claim 11, wherein the first and second connecting means comprise one of a disc-shaped plate and a plurality of rims. The yoke block according to claim 1, wherein each of the yoke blocks has a pair of protrusions along the lengthwise direction for preventing permanent magnets held between the yoke blocks at both ends of the outer peripheral portion from being separated by centrifugal force. Permanent magnet embedded rotor, characterized in that formed.