JP2008131693A - Field element, rotating electric machine and compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration in which deterioration in mechanical strength of a field magnetic element can be prevented even if a gap for blocking short circuit of a field magnetic flux is provided. <P>SOLUTION: The field magnetic element 1 is provided with a columnar laminate magnetic core 11 having soft magnetic thin plates laminated in a direction along a rotary shaft Q; a field magnetism generating section 12 buried in the rotary shaft Q side rather than a side surface 110 of the laminate magnetic core 11, and extending along the rotary shaft Q; and a gap (13) provided from both the ends of the field magnetic element 12 to the side surface 110. The field magnetism generating sections 12 each have a plate-like permanent magnet 12d and dust cores 12a, 12b fixed on the permanent magnet 12d and forming an acute-angle concave corner together with the permanent magnet 12d. The dust core 12a is provided on the rotary axis Q side rather than the permanent magnet 12d, and the dust core 12b is provided on the side surface 110 side rather than the permanent magnet 12d. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for embedding a permanent magnet in a field element employed in a rotating electrical machine. The rotating electrical machine can be employed in a compressor that compresses a refrigerant, for example.

  One configuration of a rotating electrical machine includes a field element that generates a field magnetic flux and an armature that has an armature winding and generates a rotating magnetic field by an armature current flowing therethrough. Usually, the field element is columnar and functions as a rotor, and an armature that functions as a stator is provided on the outer peripheral side thereof.

  In such a configuration, there has been proposed a field element in which a permanent magnet for generating a field magnetic flux is embedded in a magnetic body called a rotor core. In such a field element, unlike the type in which the permanent magnet is disposed on the surface of the rotor core, an annular body (magnet scattering prevention tube) for preventing the permanent magnet from scattering is not necessary. Therefore, the so-called air gap between the armature and the field element can be reduced, there is no eddy current loss in the magnet scattering prevention tube, and therefore the efficiency is increased.

  Furthermore, since the field element has a reverse saliency, the reluctance torque can be used effectively, thereby improving the torque.

  Moreover, the amount of permanent magnets can be increased by devising the embedding position of the permanent magnets, for example, by embedding them in a V-shape. This increases the magnetic loading and further improves the torque.

  However, it is necessary to provide a hole (permanent magnet embedding hole) in the rotor core in order to embed the permanent magnet. In order to increase the amount of permanent magnets to be embedded, it is necessary to increase the permanent magnet embedding holes. Therefore, the rotor core is thin on the outer peripheral side in the vicinity of the permanent magnet embedding hole. And this thin wall must hold | maintain a permanent magnet and the rotor core of the outer peripheral side from this against the centrifugal force concerning these. In order to increase the strength of the rotor core, it is conceivable to increase the width of the thin-walled portion, but this promotes the flow of the field magnetic flux in a short-circuit manner with respect to the permanent magnet that is the generation source.

  Various ideas have been made from this viewpoint, and examples are given in Patent Documents 1 to 5 below.

JP-A-9-163648 JP-A-10-285847 JP 2000-188837 A Japanese Patent Application Laid-Open No. 9-219944 JP 2005-20991 A

  In the technique disclosed in Patent Document 1, a damper bar (an element to which reference numeral 4 is given in Patent Document 1) is provided in a radial hole formed between two permanent magnets. Destruction of elements (elements given reference numeral 26 in Patent Document 1) is avoided. However, if the damper bar is made of a magnetic material, a short-circuit flow of the field magnetic flux is promoted.

  In the technique disclosed in Patent Document 2, laminated steel plates (elements given reference numeral 4 in Patent Document 2) are connected by a connection key (elements given reference numeral 13 in Patent Document 2). However, it is necessary to provide a separate part called a connection key. This dislikes increasing the number of steps. If a magnetic body is used for the connection key, the short-circuit flow of the field magnetic flux is promoted. If a nonmagnetic material is employed, the amount of permanent magnets embedded will be reduced if the width is increased from the viewpoint of strength. Moreover, it can be applied only when two magnetic poles constitute one magnetic pole.

  In the technique disclosed in Patent Document 3, the rotor core is divided into an inner peripheral side and an outer peripheral side with a permanent magnet as a boundary (elements denoted by reference numerals 12 and 13 in Patent Document 3) to prevent a short circuit of magnetic flux. Yes. However, a pipe for preventing rotor core scattering (element to which reference numeral 14 is given in Patent Document 3) is required on the outer peripheral side, and eddy current loss increases. In particular, when PWM control is performed, an increase in loss has a large effect. Further, since the air gap increases, the magnetic resistance increases.

  In the technique disclosed in Patent Document 4, a low-permeability body (an element to which reference numeral 6 is assigned in Patent Document 4) that is a permanent magnet is applied to a highly hardened iron material (reference numeral 5 in Patent Document 4). These are embedded in the rotor core (element to which reference numeral 33 is given in Patent Document 4). However, this is not effective in improving the strength of the rotor.

  Although Patent Document 5 provides a coupling between a permanent magnet and soft magnetic powder, the permeability and saturation magnetic flux density are low, which is not desirable from the viewpoint of miniaturization and high efficiency of a motor. Further, since the hysteresis loss increases, there is a disagreement that the efficiency decreases in the operation region where the rotational speed is low.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a configuration that can prevent the mechanical strength of a field element from being lowered even if a gap that inhibits short-circuiting of field magnetic flux is provided.

  A first aspect (1; 6) of a field element according to the present invention includes a columnar laminated magnetic core (11) in which soft magnetic thin plates are laminated in a direction along a rotation axis (Q), and the laminated magnet. A plurality of field generating portions (12; 120) embedded in the rotating shaft side of the side surface (110) of the core and extending in the direction, and at least one end of the field generating portion opposite to the rotating shaft And a gap (13) provided on the side. Each of the field generating portions (12; 120) is fixed to the plate-like permanent magnet (12d; 123) and the permanent magnet, and forms a first corner and an acute corner with the permanent magnet, respectively. Two dust cores (12a, 12b; 121, 122), the first dust core (12a; 121) being provided closer to the rotating shaft than the permanent magnet, The dust core (12b; 122) is provided closer to the side surface than the permanent magnet.

  A second aspect (1; 6) of the field element according to the present invention is the first aspect, and the first dust core (12a; 121) includes a pair of adjacent gaps ( 13) in the middle.

  A third aspect (1) of the field element according to the present invention is the second aspect, wherein a pair of adjacent gaps (13) are provided at both ends of the one field generating portion (12). The first dust core (12a; 121) is provided at the center of the one field generator.

  A fourth aspect (1) of the field element according to the present invention is any one of the second to third aspects, wherein a pair of adjacent ones of the field generating portions (12) are adjacent to each other. An air gap (13) is provided, and the second dust core (12b; 121) is provided at the center of the one field generating portion.

  A field element according to a fifth aspect of the present invention is any one of the second to third aspects, wherein a pair of adjacent gaps (13) are formed at both ends of the field generation part (12). ), And the second dust core (12b) is provided closer to the opposite side of the rotation direction of the field element than the center of the one field generating portion.

  A sixth aspect (6) of the field element according to the present invention is the second aspect, and the second dust core (122) is provided closer to the gap (13).

  A field element according to a seventh aspect (1; 6) of the present invention is the first aspect, wherein the first and second dust cores (12a, 12b; 121, 122) are: The cross-sectional area increases as the distance from the permanent magnet (12d, 123) increases.

  An eighth aspect (1) of the field element according to the present invention is the first aspect, wherein the air gap (13) is provided closer to the rotating shaft than the side surface, and the field generator ( 12; 120), the side surface portions (11b), which are the portions of the laminated magnetic core located on the side surface side, are connected to each other by the thin portion of the laminated magnetic core on the side surface side with respect to the gap.

  A ninth aspect (1) of the field element according to the present invention is the eighth aspect, wherein the laminated layer is located closer to the rotation axis (Q) than the field generating portion (12; 120). The magnetic core portion (11a) is connected to each other by the side surface portion (11b) and the thin portion.

  A tenth aspect (6) of the field element according to the present invention is the first aspect, wherein the air gap (13) opens on the side surface side and is more than the field generating portion (12). The laminated magnetic core portion (61a) located on the rotating shaft side includes a side surface portion (61b) that is a portion of the laminated magnetic core located on the side surface side relative to the field generating portion, and the gap (13). Are connected by the field generating part while being separated by.

  An eleventh aspect (6) of the field element according to the present invention is the tenth aspect, in which the side surface portions (61b) are separated from each other by the gap (13).

  A twelfth aspect (6) of the field element according to the present invention is the eleventh aspect, wherein the first side surface portion (61b) protrudes at one end in the direction from the other side surface portions. To do.

  A thirteenth aspect (6) of the field element according to the present invention is the twelfth aspect, in which the second side surface portion (61b) is located at the other end in the direction more than the other side surface portions. Protruding.

  A fourteenth aspect (1; 6) of a field element according to the present invention is any one of the first to eleventh aspects, wherein the length of the laminated magnetic core (11) is The length is shorter than the length of the first and second dust cores.

  A fifteenth aspect (6) of the field element according to the present invention is any one of the tenth to eleventh aspects, wherein the length of the side surface part (61b) is the first direction in the direction. And the length of the second dust core and the length of the portion (61a) of the laminated magnetic core located closer to the rotating shaft than the field generating portion (12).

  A sixteenth aspect of a field element according to the present invention is any one of the first to fifteenth aspects, wherein the field generating portion (12) is a magnetic pole surface of the permanent magnet (12d; 123). And a third dust core (12c) interposed between the first and second dust cores (12a, 12b).

  A field element according to a seventeenth aspect of the present invention is any one of the first to sixteenth aspects, wherein the permanent magnet (12d; 123) is a sintered magnet containing at least a rare earth element.

  An eighteenth aspect of the field element according to the present invention is any one of the first to sixteenth aspects, wherein the permanent magnet (12d; 123) is a bonded magnet in which magnet powder is collected by a binder, It is integrated with the first and second dust cores (12a, 12b).

  A rotating electric machine can be configured including the field element according to any one of the first to eighteenth aspects and the armature 3 disposed to face the side surface. A compressor can be configured by including the rotating electric machine and a compression mechanism driven by the rotating electric machine.

  According to the first aspect of the field element of the present invention, the first and second dust cores are fixed to the permanent magnet, while the laminated core is formed by the corners formed by the permanent magnet. Engage with. Therefore, mechanical coupling between the permanent magnet and the laminated magnetic core can be ensured. Thereby, even if the space | gap which inhibits the short circuit of the field magnetic flux which generate | occur | produces from a field generation part is provided, the fall of the mechanical strength of a field element can be prevented.

  In the second aspect of the field element according to the present invention, the magnetic flux flowing through the laminated magnetic core on the rotating shaft side of the field generating portion is branched at the center of the magnetic pole of the field element that appears on the side surface of the laminated magnetic core. Easy to flow. The magnetic pole is sandwiched between adjacent gaps. Therefore, according to the aspect of the invention, since the first dust core is disposed at a location where the magnetic flux density is low, the hysteresis loss can be reduced.

  According to the third aspect of the field element of the present invention, the force for coupling the field generating portion and the laminated magnetic core has good symmetry in the field generating portion, so the strength of the field generating portion is excellent. .

  In the fourth aspect of the field element according to the present invention, the magnetic poles of the field elements appearing on the side surfaces of the laminated magnetic core are sandwiched by the adjacent gaps, and in order to increase the reluctance torque, the permanent magnet is placed at the center of the magnetic poles. At the farthest side. Therefore, according to the invention according to this aspect, the influence of the second dust core having a low magnetic permeability and a low saturation magnetic flux density hardly affects the magnetic pole of the field element. In addition, since the force for coupling the field generating portion and the laminated magnetic core has good symmetry in the field generating portion, the strength of the field generating portion is excellent.

  In the fifth aspect of the field element according to the present invention, the magnetic poles of the field elements appearing on the side surfaces of the laminated magnetic core are sandwiched between adjacent gaps, and the magnetic flux distribution is more biased toward the rotational direction side than the center of the magnetic poles. Therefore, according to the invention according to this aspect, since the second dust core is disposed at a location where the magnetic flux density is low, the hysteresis loss can be reduced.

  According to the sixth aspect of the field element of the present invention, the second dust core, like the gap, inhibits the short-circuiting of the field magnetic flux generated from the field generating portion. Further, since the second dust core is engaged with the laminated magnetic core at the end of the field generating portion, the effect of mechanically coupling the permanent magnet and the laminated magnetic core is high.

  According to the seventh aspect of the field element of the present invention, the magnetic resistance viewed from the permanent magnet can be reduced by reducing the contact area between the first and second dust cores and the permanent magnet.

  According to the eighth aspect of the field element of the present invention, the precision of the outer diameter of the field element can be controlled with the precision of punching the soft magnetic thin plate.

  According to the ninth aspect of the field element of the present invention, handling of the laminated magnetic core is easy.

  According to the tenth aspect of the field element of the present invention, the length of the laminated magnetic core in the rotation axis direction can be made different between the side surface portion and the portion located on the rotation axis side.

  According to the eleventh aspect of the field element of the present invention, the side surface portion of the laminated magnetic core can function as a balancer. Further, it can be punched by effectively using the area of the soft magnetic thin plate.

  According to the 12th aspect of the field element concerning this invention, a 1st side part can be functioned as a balancer.

  According to the thirteenth aspect of the field element according to the present invention, since the second side surface portion can also function as a balancer, it is not necessary to provide a balancer on the shaft supported by the field element.

  According to the fourteenth aspect of the field element of the present invention, the magnetic saturation of the first and second dust cores having a low saturation magnetic flux density is reduced. At this time, the magnetic flux passing through the first and second dust cores has a larger component in the rotation axis direction, but is preferable because the dust core is isotropic. Further, a large permanent magnet can be employed, which is desirable from the viewpoint of increasing the flux linkage.

  According to the fifteenth aspect of the field element of the present invention, the magnetic flux is prevented from flowing into the shaft supported by the field element by enlarging the portion functioning as the back yoke with respect to the magnetic pole of the field element. It is also easy to support the shaft. Moreover, when the laminated magnetic core between adjacent side surface parts functions as a q-axis magnetic path, the saturation is also relaxed.

  According to the sixteenth aspect of the field element of the present invention, the fixation between the permanent magnet and the first and second dust cores can be strengthened.

  According to the seventeenth aspect of the field element of the present invention, since the magnetic energy product of the permanent magnet is high, the output torque is improved. Further, since the square ratio of the hysteresis curve of the permanent magnet is large, the influence of thermal demagnetization due to heat generation when the first and second dust cores are fixed is small. It is also suitable for driving in a high temperature environment.

  According to the eighteenth aspect of the field element of the present invention, the strength at which the permanent magnet and the first and second dust cores are fixed is high. In addition, the thickness of the first and second dust cores can be reduced, thereby reducing the short circuit of the field magnetic flux.

First embodiment.
FIG. 1 is a sectional view showing the structure of a field element 1 according to a first embodiment of the present invention. The sectional view shows a section perpendicular to the rotation axis Q of the field element 1.

  The field element 1 includes a laminated magnetic core 11 and a field generating unit 12 that is embedded in the core and generates a field magnetic flux. The laminated magnetic core 11 has a columnar shape along the rotation axis Q, for example, a cylindrical shape. However, the side surface 110 does not necessarily have to be a perfect circle in the cross section. For example, for the purpose of reducing cogging torque, the distance from the rotation axis Q to the side surface 110 may depend on the position in the circumferential direction. Good. The laminated magnetic core 11 is configured by laminating soft magnetic thin plates in a direction along the rotation axis Q.

  The field generator 12 is embedded on the rotation axis Q side with respect to the side surface 110 of the laminated magnetic core 11, extends in a direction along the rotation axis Q, and is provided in a plurality.

  The field element 1 has a gap 13 in the laminated magnetic core 11. The air gap 13 is provided on at least one end of the field generator 12, here on the opposite side of the rotation axis Q from both ends. The laminated magnetic core 11 is divided into a portion 11 a on the rotation axis Q side and a portion 11 b on the side surface 110 side by the gap 13. The air gap 13 prevents the field magnetic flux generated from the field generating part 12 from flowing in a short circuit.

  Here, the air gap 13 is provided closer to the rotation axis Q than the side surface 110 of the laminated magnetic core 11, leaving a thin portion. And the parts 11b are mutually connected by the thin part. Thus, it is desirable that the side surface 110 is continuous at any position in the circumferential direction from the viewpoint of controlling the accuracy of the outer diameter of the field element 1 with the accuracy of punching the soft magnetic thin plate.

  In addition, it is desirable that the portions 11 a and 11 b are also connected to each other by the thin portion from the viewpoint of easy handling of the laminated magnetic core 11.

  However, since the portions 11a and 11b are connected as will be described later, the thin portion may not be provided. More specifically, the gap 13 may open on the side opposite to the rotation axis Q. Advantages obtained by opening the gap 13 in this manner will be described later in detail in a fourth embodiment.

  The portion 11 a has a portion 14 sandwiched between the portions 11 b through the gap 13. The portion 14 functions as a so-called q-axis magnetic path and contributes to the reluctance torque.

  Each of the field generators 12 includes dust cores 12a and 12b and a plate-like permanent magnet 12d. The dust cores 12a and 12b are fixed to the permanent magnet 12d on the rotating shaft Q side and the side surface 110 side, respectively. The dust cores 12a and 12b form an acute corner with the permanent magnet 12d. The permanent magnet 12d exhibits magnetic pole surfaces having different polarities on the rotating shaft Q side and the side surface 110 side.

  While the dust cores 12a and 12b are fixed to the permanent magnet 12d, the dust cores 12a and 12b are engaged with the laminated core 11 by the corners formed with the permanent magnet 12d. Therefore, the mechanical coupling between the permanent magnet 12d and the laminated magnetic core 11 can be ensured. More specifically, the dust cores 12a and 12b are engaged with the portions 11a and 11b, respectively, so that the portions 11a and 11b are connected to each other through the field generating portion 12. Thereby, even if the space | gap 13 which inhibits the short circuit of the field magnetic flux which generate | occur | produces from the field generation part 12 is provided, the fall of the mechanical strength of the field element 1 can be prevented. Moreover, since the dust cores 12a and 12b are magnetic bodies, it is difficult to impair the function as the rotor core.

  In general, a permanent magnet has a low degree of freedom in shape and a low mechanical strength in a sintering process. Therefore, it is difficult to form an acute corner with only a permanent magnet, and the function of connecting the portions 11a and 11b is low. Therefore, it is desirable to form an acute corner with a permanent magnet by using the dust cores 12a and 12b which have a high degree of freedom in shape and are also magnetic materials.

  Moreover, even if the dust cores 12a and 12b having a large hysteresis loss are employed at the positions where the dust cores 12a and 12b are provided, the fluctuation of the magnetic flux density is small. On the other hand, since the side surface 110 is formed by the laminated magnetic core 11, the magnetic permeability is high and the iron loss (particularly hysteresis loss) is small. Therefore, an increase in copper loss due to a decrease in magnetic permeability and an increase in iron loss due to an increase in hysteresis loss are suppressed as compared with the case where a dust core is used for the entire rotor core. As the soft magnetic thin plate constituting the laminated magnetic core 11, it is desirable to employ an electromagnetic steel plate or a silicon steel plate having a small hysteresis loss. This is because, particularly when the drive frequency is low speed rotation of several hundred Hz or less, the laminated magnetic core (electromagnetic steel sheet) generally has a smaller iron loss than the dust core (iron-based).

  The permanent magnet 12d is preferably a sintered magnet containing at least a rare earth element. Specifically, for example, it is desirable to employ neodymium / iron / boron materials. Since such a sintered magnet has a high magnetic energy product, the output torque is improved. Further, since the square ratio of the hysteresis curve of the permanent magnet is large, the influence of thermal demagnetization due to heat generation when the dust cores 12a and 12b are fixed is small. It is also suitable for driving in a high temperature environment. In addition, by covering the periphery of the permanent magnet with a dust core having a high specific resistance instead of a laminated magnetic core, an increase in iron loss due to eddy current generated by the laminated magnetic core via the permanent magnet can be prevented.

  The permanent magnet 12d is a bonded magnet in which magnet powder is collected by a binder, and is preferably integrated with the dust cores 12a and 12b. The integration is exemplified in Patent Document 5, for example. This is because the strength with which the permanent magnet 12d and the dust cores 12a and 12b are fixed increases. Further, the thickness of the dust cores 12a and 12b can be reduced, thereby reducing the short circuit of the field magnetic flux.

  FIG. 2 is a cross-sectional view showing a configuration in which one field generating portion 12 is extracted from the field element 1, and the cross section is also perpendicular to the rotation axis Q as in FIG. The laminated magnetic core 11 is provided with a through hole 12e through which the field generating portion 12 is inserted. For insertion of the field generating portion 12 into the through hole 12e, press-fitting or shrink-fitting can be employed.

  FIG. 2 illustrates an example in which the through-hole 12e communicates with the gap 13. However, the two may be arranged as close to each other as possible to suppress a short circuit of the field magnetic flux.

  In addition to the through hole 12e, the laminated magnetic core 11 is penetrated by a fastening hole 15 into which a fastener (not shown) for fastening a laminated soft magnetic thin plate is inserted, and a rotating shaft (not shown). A shaft hole 10 is provided.

  Without using a fastener, for example, a so-called calamase may be employed in which unevenness is provided on a soft magnetic thin plate and the unevenness is entangled between adjacent soft magnetic thin plates. In this case, of course, the fastening hole 15 is not necessary. However, a fastener and Karamase may be used in combination.

  FIG. 3 is a diagram showing details of the field generator 12 and shows a structure in a plane perpendicular to the rotation axis Q. The field generator 12 preferably has a dust core 12c interposed between the magnetic pole surface of the permanent magnet 12d and the dust cores 12a and 12b. This is because the permanent magnet 12d and the dust cores 12a and 12b can be firmly fixed.

  FIG. 4 is a perspective view showing the positional relationship among the permanent magnet 12d, the dust cores 12a, 12b, 12c and the through hole 12e. However, it is desirable that the dust cores 12a, 12b, and 12c be fixed to the permanent magnet 12d as described above, rather than the permanent magnet 12d being inserted into the dust cores 12a, 12b, and 12c.

  FIG. 5 is a diagram showing another example of the details of the field generator 12 and shows a structure in a plane perpendicular to the rotation axis Q. The field generator 12 is not provided with the dust core 12c at the end of the permanent magnet 12d that is not the magnetic pole surface. Such a configuration is desirable from the viewpoint of excluding factors that cause the field magnetic flux to flow in a short circuit. At this time, for example, the permanent magnet 12d and the dust cores 12a and 12b are fixed by adhesion.

  The cross-sectional area of the dust cores 12a and 12b increases as the distance from the permanent magnet 12d increases. The cross-sectional area here is the area of the surface perpendicular to the radial direction. The acute corners as described above can be formed, and the magnetic resistance viewed from the permanent magnet 12d can be reduced by reducing the contact area between the dust cores 12a and 12b and the permanent magnet 12d.

  Here, the dust cores 12a and 12b have a wedge shape, but may have other shapes as long as they have a function of engaging, such as a T-shape.

  In the direction along the rotation axis Q, the structure shown in FIG. By providing a so-called skew in the field element, torque ripple can be reduced. FIG. 6 exemplifies a structure in which the structure shown in FIG. 1 is overlapped in two stages, and the structure shown by a broken line is arranged on the back side of the drawing. The field generators 12A and 12B and the air gaps 13A and 3B correspond to the field generator 12 and the air gap 13 in FIG. 1, respectively.

  In addition, since the structure of both should form a field element, the position on the sectional view of the hole 15 for fasteners and the shaft hole 10 corresponds in both. In order to prevent the field magnetic flux in one structure from flowing in a short circuit through the rotor core in the other structure, it is desirable to interpose a non-magnetic spacer therebetween. Of course, the spacer is not necessary if the amount of field magnetic flux that flows in a short-circuiting manner is sufficient in terms of the performance of the rotating electrical machine.

  The skew angle in such a two-tiered structure is optimally an angle corresponding to 1/2 of one cycle of the torque ripple to be canceled. Among the torque ripples, regarding the cogging torque, when the number of magnetic poles of the field element is four as illustrated in FIGS. 1 and 6, the number of slots of the armature (not shown) is 12, 24, and 36. If present, one period of the cogging torque is 30 degrees, 15 degrees, and 10 degrees, respectively. Therefore, it is desirable to select the skews at 15 degrees, 7.5 degrees, and 5 degrees, respectively. Depending on the shape, the period of the cogging torque may be shorter than the above value.

  If the slot harmonics are to be reduced, half of the slot pitch is selected as the skew angle. The torque ripple when using a three-phase rotating magnetic field is 30 degrees when the number of magnetic poles of the field element is four. Therefore, in order to reduce the torque ripple in this case, it is desirable to select the skew angle as 15 degrees.

  Of course, the skew angle may slightly deviate from the selected value. If the number of stages in which the structure of FIG. 1 is overlapped is N, the skew angle between the two stages can be selected by multiplying the selection value in the case of the two stages obtained as described above by 2 / N. Good.

  Although illustration is omitted, the field element 1 may be provided with an end plate at the end of the rotation axis Q so that the field generator 12 does not come off from the laminated core 11 along the rotation axis Q. Alternatively, a step may be provided at a site where the field generating unit 12 and the laminated core 11 are in contact so that the field generating unit 12 does not come off along the rotation axis Q.

Second embodiment.
7 and 8 are magnetic flux diagrams simulating the magnetic flux flowing between the field element 1 and the armature 2, and the rotation direction is counterclockwise in the figure. Here, only 1/4 of the configuration of the field element 1 and the armature 2 is shown. In the portion 11a, the magnetic flux tends to branch and flow on both sides with the center of the permanent magnet 12d as a boundary. This is because the permanent magnet 12d is sandwiched between adjacent gaps 13 and the center of the permanent magnet 12d is the center of the magnetic pole of the field element 1.

  Therefore, as shown in FIG. 1, by arranging the dust core 12a at a location where the magnetic flux density is low, that is, in the middle between a pair of adjacent gaps 13, the dust core 12a and thus the field element 1 can reduce the hysteresis loss.

  In particular, as shown in FIG. 1, a pair of adjacent gaps 13 are provided at both ends of one field generating portion 12, and the dust core 12 a is provided at the center of the field generating portion 12. Is desirable in that the strength of the field generating portion 12 is excellent. This is because the force that couples the field generator 12 and the laminated core 11 has good symmetry in the field element generator 12.

  The magnetic pole of the field element 1 appearing on the side surface 110 is sandwiched between the adjacent gaps 13. In order to increase the reluctance torque, the permanent magnet 12d is farthest from the side surface 110 at the center of the magnetic pole. Therefore, it is desirable that the dust core 12 b is also provided at the center of the field generating portion 12. This is because the influence of the dust core 12b having a low magnetic permeability and a low saturation magnetic flux density hardly affects the magnetic poles of the field element 1. In addition, since the force that couples the field generator 12 and the laminated core 11 has good symmetry in the field element generator 12, the strength of the field generator 12 is excellent.

  Providing the dust core 12b in the center of the field generator 12 in this way is particularly desirable when there is no load or when the rotating magnetic field is small. However, when the magnetic flux due to the armature current is large, it is desirable to arrange the dust core 12b as follows.

  FIG. 9 is a sectional view showing the structure of a field element 1 according to the second embodiment of the present invention, and shows a section corresponding to FIG. The field element 1 rotates around the rotation axis Q in the counterclockwise direction in the figure.

  In the second embodiment, as compared with the first embodiment, the dust core 12b is closer to the opposite side (reverse side) of the rotation direction of the field element 2 than the center of the field generating unit 12. It differs in that it is provided. As can be seen from FIG. 8, the magnetic flux distribution is more biased toward the rotational direction side (forward side) than the center of the magnetic pole of the field element 1. Therefore, by disposing the dust core 12b at a location where the magnetic flux density is low, the hysteresis loss generated in the dust core 12b and consequently in the field element 1 can be reduced.

Third embodiment.
FIG. 10 is a sectional view showing the structure of a field element 1 according to the third embodiment of the present invention, and shows a section corresponding to FIG. In the third embodiment, the field generator 12 according to the first embodiment is replaced with a field generator 120. However, in the third embodiment, the magnetic poles of the field element 1 are formed on the side surface 110 by the field magnetic flux supplied from the pair of field magnetic flux generators 120.

  FIG. 11 is a cross-sectional view showing the configuration of the laminated magnetic core 11, and FIG. 12 shows the configuration of the field generating unit 120 employed as a pair. The laminated magnetic core 11 is provided with a through hole 124 through which the field generating portion 120 is inserted, and the rotation axis Q side thereof communicates with each other through the gap 16. Further, the gap 13 communicates with the side surface 110 side. However, the air gap 13 and the through-hole 124 do not necessarily need to communicate with each other, and both may be arranged as close to each other as possible to suppress a short circuit of the field magnetic flux. The same applies to the positional relationship between the gap 16 and the through hole 124.

  Also in the third embodiment, a fastening hole 15 and a shaft hole 10 are provided.

  The field generation unit 120 includes dust cores 121 and 122 and a permanent magnet 123 corresponding to the dust cores 12a and 12b and the permanent magnet 12d of the field generation unit 12, respectively.

  The dust cores 121 and 122 are fixed to the permanent magnet 123 on the rotating shaft Q side and the side surface 110 side, respectively. The fixing method and materials are exemplified in the first embodiment. 10 and 12, the thin dust core that covers the periphery of the permanent magnet 123 is omitted. The dust cores 121 and 122 together with the permanent magnet 123 form an acute corner. The permanent magnet 123 presents magnetic pole surfaces having different polarities on the rotation axis Q side and the side surface 110 side. The dust cores 121 and 122 have a larger cross-sectional area as they move away from the permanent magnet 123. Therefore, similarly to the first embodiment, even if the air gap 13 is provided, a decrease in the mechanical strength of the field element 1 can be reduced.

  However, in the third embodiment, the pair of field generators 12 correspond to one magnetic pole of the field element 1. Therefore, the dust core 121 fixed to the permanent magnet 123 from the rotating shaft Q side is disposed at the center of the magnetic pole, that is, at the center between the pair of gaps 13, and as a result, adjacent to the gap 16. Be placed. As a result, the same effect as the arrangement of the dust core 12a at the position described in the second embodiment can be obtained.

  In addition, the magnet 123 is prevented from moving toward the side surface 110 in the through hole 124 by the engagement between the dust core 121 and the portion 11a.

  It is not desirable to arrange the dust core 121 in place of the gap 16. This is because the field magnetic flux flows in a short circuit at this position. Therefore, as shown in FIG. 11, it is desirable to dispose the dust core 121 with the gap 16 in between.

  Although it is conceivable to place the dust core 121 closer to the air gap 13 than the air gap 16, in view of the fact that the portion 11a functions as a back yoke, as shown in FIG. It is desirable to arrange the dust core 121.

  On the other hand, the dust core 122 is provided adjacent to the gap 13 here, rather than the gap 13. The dust core 122 impedes the short-circuiting of the field magnetic flux generated from the field generator 120, similarly to the gap 13. Further, since the dust core 122 is engaged with the laminated magnetic core 11 at the end of the field generating portion 120, the effect of mechanically coupling the permanent magnet 123 and the laminated magnetic core 11 is high. And since the parts 11a and 11b are connected by the thin part on the side surface 110 side rather than the space | gap 13, in order to prevent destruction of the said thin part, it is desirable to provide the powder magnetic core 122 in the vicinity of the space | gap 13. FIG.

  In the third embodiment, a skew can be provided as in the first embodiment.

Fourth embodiment.
FIG. 13 is a sectional view showing the structure of a field element 6 according to the fourth embodiment of the present invention, and shows a section corresponding to FIG. The fourth embodiment has a configuration in which the laminated magnetic core 11 according to the first embodiment is replaced with laminated magnetic cores 61 a and 61 b separated via a gap 63. That is, the laminated magnetic cores 61 b are separated from each other by the gap 13.

  The laminated magnetic cores 61a and 61b, like the laminated magnetic core 11, have a columnar shape, for example, a columnar shape along the rotational axis Q, and are configured by stacking soft magnetic thin plates in the direction along the rotational axis Q. . The laminated magnetic cores 61a and 61b are provided with fastening holes 65 and 66, respectively, and fasteners (not shown) for fastening the laminated soft magnetic thin plates are inserted therethrough. A shaft hole 60 is also provided in the laminated magnetic core 61a.

  The gap 63 and the laminated magnetic cores 61a and 61b correspond to the gap 13 and the portions 11a and 11b (see FIG. 1), respectively. More specifically, the laminated magnetic core 61b is annularly arranged around the rotation axis Q and surrounds the laminated magnetic core 61a. The laminated magnetic core 61 a has a portion 64 extending in four directions to the side opposite to the rotation axis Q (side surface side of the field element 6), and this is sandwiched by the laminated magnetic core 61 b through the gap 63. The portion 64 corresponds to the portion 14 (see FIG. 1) and functions as a so-called q-axis magnetic path. The laminated magnetic cores 61a and 61b are engaged with the field generating unit 12 from the rotation axis Q side and the side surface side (the side opposite to the rotation axis Q), respectively.

  Thus, the field element 6 can be grasped as a structure in which the air gap 13 is opened toward the opposite side of the rotation axis Q in the field element 1 shown in FIG.

  FIG. 14 is a cross-sectional view showing a configuration before the laminated magnetic cores 61a and 61b and the field generating unit 12 are engaged. For simplicity, only one laminated magnetic core 61b and field generator 12 are shown, but in reality, all four are used.

  The laminated magnetic core 61a is provided with a recess 67 that engages with the dust core 12a, and the laminated magnetic core 61b is provided with a recess 68 that engages with the dust core 12b.

  Since the structure is as described above, the field element 6 according to the third embodiment works as well as the field element 1 according to the first embodiment. Furthermore, as described in the second embodiment, the positions of the dust cores 12a and 12b may be devised.

  One advantage peculiar to the present embodiment is that there is no thin portion outside the air gap 13 (opposite to the rotation axis Q), so that the short-circuit flow of the field magnetic flux can be further inhibited. It is done.

  Another advantage is that the area of the soft magnetic thin plate can be effectively used when punching the soft magnetic thin plate in order to obtain the laminated magnetic cores 61a and 61b. FIG. 15 is a cross-sectional view showing a state in which the field generating portion 12 is removed from the field element 6 and the gaps 63 are eliminated by further assembling. Since the laminated magnetic cores 61a and 61b can be obtained by punching out the soft magnetic thin plate with such a shape, and laminating and fastening with the fastening holes 65 and 66, the soft magnetic thin plate that is wasted during the punching can be obtained. The amount can be reduced.

  Although there are still other advantages specific to the present embodiment, this will be described in the sixth embodiment for convenience of explanation.

Fifth embodiment.
In the fifth embodiment, the length of each part in the direction of the rotation axis Q in the field element 1 is devised. Both FIG. 16 and FIG. 17 are cross-sectional views showing a cross section parallel to the rotation axis Q at the position AA in FIG. In the cross-sectional view, a fastener 18 that is inserted into the fastening hole 15 and a fastener 19 that fastens the laminated magnetic core 11 (shown as portions 11a and 11b in the cross-section) are also illustrated. Also shown is a rotating shaft 3 that is inserted through the shaft hole 10.

  In the structure shown in FIG. 16, in the direction along the rotation axis Q, the length of the laminated magnetic core 11 is shorter than the length of the dust cores 12a and 12b. In other words, the lengths of the dust cores 12 a and 12 b are longer than the length of the laminated magnetic core 11. Therefore, even if the saturation magnetic flux density of the dust cores 12a and 12b is low, the magnetic saturation in them can be reduced. The magnetic flux passing through the dust cores 12a and 12b has a larger component along the rotation axis Q. However, the dust core is generally isotropic and is preferable. Further, a large permanent magnet 12d can be employed, which is desirable from the viewpoint of increasing the linkage flux.

  In the structure shown in FIG. 17, in the direction along the rotation axis Q, the length of the laminated magnetic core 11 is longer than the length of the dust cores 12a and 12b. This is desirable in that the cross-sectional area of the magnetic path of the portion 14 (see FIG. 1) is expanded, and the reluctance torque is less likely to be saturated even if the magnetic flux due to the armature current increases.

Sixth embodiment.
In the sixth embodiment, the length of each part in the rotation axis Q direction in the field element 6 is devised. 18 and 19 are cross-sectional views showing cross sections parallel to the rotation axis Q at positions BB and CQC in FIG. 13, respectively.

  In the cross-sectional view, a fastener 18 that is inserted into the fastening hole 65 and a fastener 19 that fastens the laminated magnetic core 61b are also illustrated. Also shown is a rotating shaft 3 that is inserted through the shaft hole 60.

  In the structure shown in FIG. 18, the laminated magnetic core 61b shown on the left side protrudes at the upper end in the direction along the rotation axis Q from the laminated magnetic core 61b shown on the right side. Further, the laminated magnetic core 61b illustrated on the right side protrudes at the lower end in the direction along the rotation axis Q with respect to the laminated magnetic core 61b illustrated on the left side. Therefore, the laminated magnetic core 61 b functions as a balancer for the rotating shaft 3. Only one laminated magnetic core 61b may protrude only at one end in the direction along the rotation axis Q. When a balancer (not shown) is provided on the rotary shaft 3, the laminated magnetic core 61b functions as an auxiliary balancer for the balancer. Further, when there are two protruding portions as shown in FIG. 18, a main balancer (hereinafter referred to as “main balancer”) and an auxiliary balancer are provided without providing a balancer as a separate part on the rotating shaft 3. Both of the functions (hereinafter referred to as “sub-balancer”) can be assigned to the laminated magnetic core 61b.

  Providing such a balancer is particularly suitable when the load driven by the rotating shaft 3 is unbalanced, for example, when the rotating shaft 3 drives the compressor.

  In the structure shown in FIG. 19, in the direction along the rotation axis Q, the length of the laminated magnetic core 61b is shorter than any of the lengths of the dust cores 12a and 12b and the laminated magnetic core 61a. .

  Since the laminated magnetic core 61a functions as a back yoke with respect to the magnetic poles of the field element 6, enlarging this prevents the magnetic flux from flowing into the rotating shaft 3 even if it is a magnetic body. Moreover, it is easy to support the rotating shaft 3. Further, the saturation of the portion 64 functioning as the q-axis magnetic path is also alleviated.

  In the above example, the case where the field element has four poles is illustrated, but the number of poles is not limited to this. The permanent magnets 12d and 123 are plate-shaped, but are not necessarily flat and may be arc-shaped in cross-sectional view.

Application to compressors.
FIG. 20 is a cross-sectional view showing a configuration of a compressor that employs a rotating electric machine including a field element 6 and an armature 3 that faces the side surface thereof. The compressor includes a casing 4 and stores therein a compression mechanism 41 that compresses, for example, a refrigerant. The compression mechanism 41 is driven by the rotation of the rotary shaft 3. The armature 3 has an armature winding 32 and a stator core 31 around which the armature winding 32 is wound. The stator core 31 is fixed to the inner wall of the casing 4.

  The two laminated magnetic cores 61b appearing in FIG. 20 protrude as illustrated in FIG. 18, and each of them functions as a main balancer and a sub-balancer. Therefore, the main balancer is not provided in the compressor.

  The weights of the compression mechanism 41, the main balancer, and the sub-balancer are M1, M2, and M3, and the distances (eccentricity) of the center of gravity from the rotation axis Q are R1, R2, and R3. , Z1, Z2, and Z3 satisfy M1 · R1 + M2 · R2 + M3 · R3 = 0 from the relationship of taking a static balance, and M1 · R1 · Z1 + M2 · R2 · Z2 + M3 · R3 · from the relationship of taking a dynamic balance. It is desirable to satisfy Z3 = 0.

  Since the eccentricities R1, R2, and R3 are determined from the viewpoint of the structure of the compressor, the laminated thicknesses of the two laminated magnetic cores 61b may be different in order to appropriately set the weights M2 and M3.

It is sectional drawing which shows the structure of the field element concerning 1st Embodiment of this invention. It is sectional drawing which shows the structure which extracted one field generation | occurrence | production part from the field element. It is a figure which shows the detail of a field generating part. It is a perspective view which shows the positional relationship of a permanent magnet, a dust core, and a through-hole. It is a figure which shows the other example of the detail of a field generation | occurrence | production part. It is a figure which shows the field element provided with the skew. It is a magnetic flux diagram which simulated the magnetic flux which flows between a field element and an armature. It is a magnetic flux diagram which simulated the magnetic flux which flows between a field element and an armature. It is sectional drawing which shows the structure of the field element concerning the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the field element concerning 3rd Embodiment of this invention. It is sectional drawing which shows the structure of a laminated magnetic core. It is sectional drawing which shows the structure of the field generating part employ | adopted as a pair. It is sectional drawing which shows the structure of the field element concerning 4th Embodiment of this invention. It is sectional drawing which shows the structure before engaging a laminated magnetic core and a field generation | occurrence | production part. It is sectional drawing which shows the state which removed the field generation | occurrence | production part from the field element, and also packed and eliminated the space | gap. It is sectional drawing which shows a cross section parallel to a rotating shaft in position AA of FIG. It is sectional drawing which shows a cross section parallel to a rotating shaft in position AA of FIG. It is sectional drawing which shows a cross section parallel to a rotating shaft in position BB of FIG. It is sectional drawing which shows a cross section parallel to a rotating shaft in position CQC of FIG. It is sectional drawing which shows the structure of the compressor which employ | adopted the rotary electric machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,6 Field element 11, 61a, 61b Laminated magnetic core 11a, 11b, 14 part 12, 120 Field generating part 12a, 12b, 12c, 121, 122 Dust core 12d, 123 Permanent magnet 13 Air gap 3 Armature 4 Compressor

Claims (20)

A columnar laminated magnetic core (11) in which soft magnetic thin plates are laminated in a direction along the rotation axis (Q);
A plurality of field generating portions (12; 120) embedded in the rotating shaft side of the side surface (110) of the laminated magnetic core and extending in the direction;
A gap (13) provided on at least one end of the field generating portion on the side opposite to the rotating shaft,
Each of the field generators (12; 120)
A plate-like permanent magnet (12d; 123);
First and second dust cores (12a, 12b; 121, 122) fixed to the permanent magnet and forming an acute corner with the permanent magnet, respectively.
The first dust core (12a; 121) is provided closer to the rotating shaft than the permanent magnet,
The second dust core (12b; 122) is a field element (1; 6) provided closer to the side surface than the permanent magnet.   The field element (1; 6) according to claim 1, wherein the first dust core (12a; 121) is provided at a center between a pair of adjacent gaps (13). A pair of adjacent gaps (13) are provided at both ends of the one field generator (12),
The field element (1) according to claim 2, wherein the first dust core (12a; 121) is provided in the center of the one field generating portion. A pair of adjacent gaps (13) are provided at both ends of the one field generator (12),
The field element (1) according to any one of claims 2 to 3, wherein the second dust core (12b; 121) is provided at the center of the one field generating portion. . A pair of adjacent gaps (13) are provided at both ends of the one field generator (12),
The second dust core (12b) according to any one of claims 2 to 3, wherein the second dust core (12b) is provided closer to a side opposite to a rotation direction of the field element than a center of the one field generating portion. The field element (1) according to one.   The field element (6) according to claim 2, wherein the second dust core (122) is provided closer to the gap (13).   The field element (1) according to claim 1, wherein the first and second dust cores (12a, 12b; 121, 122) have a larger cross-sectional area as they move away from the permanent magnet (12d, 123). 6). The gap (13) is provided closer to the rotating shaft than the side surface,
The side surface portions (11b), which are portions of the laminated magnetic core located on the side surface side with respect to the field generating portion (12; 120), are formed by the thin portion of the laminated magnetic core on the side surface side with respect to the gap. 2. A field element (1) according to claim 1, which is interconnected.   The laminated magnetic core portion (11a) located closer to the rotating shaft (Q) than the field generating portion (12; 120) is interconnected by the side surface portion (11b) and the thin portion. The field element (1) according to claim 8. The gap (13) opens on the side surface;
The laminated magnetic core portion (61a) located closer to the rotation axis than the field generating portion (12) is a side surface that is the laminated magnetic core portion located closer to the side surface than the field generating portion. The field element (6) according to claim 1, wherein the field element (6) is connected to the portion (61b) by the field generating part while being separated by the gap (13).   The field element (6) according to claim 10, wherein the side portions (61b) are separated from each other by the gap (13).   The field element (6) according to claim 11, wherein the first side surface portion (61b) protrudes at one end in the direction from the other side surface portions.   The field element (6) according to claim 12, wherein the second side surface portion (61b) protrudes from the other side surface portion at the other end in the direction.   The field element according to any one of claims 1 to 11, wherein in the direction, the length of the laminated magnetic core (11) is shorter than the length of the first and second dust cores. (1; 6).   In the direction, the length of the side surface portion (61b) is the length of the first and second dust cores, the laminated magnet positioned closer to the rotating shaft than the field generating portion (12). The field element (6) according to any one of claims 10 to 11, wherein the field element (6) is longer than any of the lengths of the core portion (61a).   The field generating portion (12) includes a third dust magnet interposed between the magnetic pole surface of the permanent magnet (12d; 123) and the first and second dust cores (12a, 12b). The field element according to any one of claims 1 to 15, further comprising a core (12c).   The field element according to any one of claims 1 to 16, wherein the permanent magnet (12d; 123) is a sintered magnet containing at least a rare earth element.   The permanent magnet (12d; 123) is a bonded magnet obtained by collecting magnet powder with a binder, and is integrated with the first and second dust cores (12a, 12b). The field element according to any one of the above.   A rotating electric machine comprising the field element according to any one of claims 1 to 18 and an armature (3) disposed to face the side surface.   A compressor (4) comprising the rotating electrical machine according to claim 19 and a compression mechanism (41) driven by the rotating electrical machine.

Images