JP2008187863A - Axial gap rotary electric machine and compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ease an effect of demagnetization which acts on permanent magnets of a rotor, in an axial gap rotary electric machine in which a coil-wound stator is arranged at one side of a rotor in the direction of rotation axis and a non-coil-wound stator is arranged at the other side. <P>SOLUTION: The coil-wound stator 30 and the non-coil-wound stator 40 are arranged at both sides of the rotor 20 along the direction of rotation axis 28a. The rotor 20 has rotor cores 24 arranged at the coil-wound stator 30 side only of each permanent magnet 22 virtually. No rotor core is provided at the non-coil-wound stator 40 side of each permanent magnet 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an axial gap type rotating electrical machine.

  The axial gap type motor has a configuration in which a stator and a rotor are provided with a gap along a rotation axis. Even if such an axial gap type motor is made thin in the direction of the rotation axis, the magnetic pole surface of the field permanent magnet can be widened, and the winding space factor can be easily increased. Research is being carried out as a form in which torque or output can be increased as compared with the above.

  However, in the axial gap type motor, since a suction force acts between the stator and the rotor along the rotation axis direction, there is a problem that the bearing loss is increased and the bearing life is shortened. is there.

  In addition, there exist patent documents 1-3 as a prior art relevant to this invention.

  Patent Document 1 discloses a configuration in which a first yoke and a second yoke are disposed on both sides of a stator having a coil along a rotation axis direction, and a permanent magnet is provided on the first yoke. ing.

  Further, in Patent Document 2, in a single-phase induction motor, a first stator and a second stator are provided on both sides of the rotor along the rotation axis direction, a main winding is provided on the first stator, The structure which provided the auxiliary | assistant coil | winding in 2 stators is disclosed.

  Patent Document 3 discloses an axial gap type rotating electrical machine in which a rotor is disposed opposite to a stator with an air gap interposed therebetween, and an auxiliary yoke is provided on the opposite side of the roller with an air gap interposed therebetween.

Japanese Patent Laid-Open No. 61-185040 JP-A-1-174248 JP 2006-353078 A

  In the axial gap type motor, in order to prevent the force acting in the axial direction, for example, two rotors are provided on both sides of one winding stator along the rotational axis direction, or the rotational shaft is also the same. Along the direction, two winding stators are provided on both sides of one rotor, for example, to interact with each other so as to cancel the suction force acting at a plurality of locations, thereby reducing the total suction force in the axial direction. Such a configuration is proposed.

  However, the configuration in which two rotors are provided as in the former has a problem that the bearing configuration becomes complicated and the rotating shaft becomes long and torsional vibration is likely to occur.

  In addition, although patent document 1 is disclosing the structure which provided the permanent magnet only in one rotor, since it is a structure which has two rotors, the said problem cannot be solved.

  Also, in the latter case, in the configuration in which two winding stators are provided, it is necessary to divide the coils into two winding stators, so that the number of coils is doubled. There was a problem that the dead space due to the connection between them increased.

  Incidentally, in the technique disclosed in Patent Document 2, the main winding is provided in the first stator and the auxiliary winding is provided in the second stator. However, in the single-phase induction motor, the current that flows through the main winding is larger than the current that flows through the auxiliary winding. That is, Patent Document 2 does not disclose or suggest a technique for preventing a force acting in the axial direction in the first place. In addition, since the windings are provided in both stators, it can be evaluated that the configuration is the same as the configuration in which the two winding stators are provided, and no solution to the above problem is presented.

  Here, in Patent Document 3, a stator having a coil is disposed on one side of a rotor, and an auxiliary yoke is disposed on the other side. For this reason, the magnetic attraction force acting in the axial direction can be canceled as much as possible while suppressing an increase in the number of coils.

  However, in Patent Document 3, since the permanent magnet of the rotor is directly opposed to the stator having the coil, the influence of the demagnetizing field acting on the permanent magnet of the rotor is large due to the external magnetic field of the excited stator. There's a problem.

  Therefore, the present invention provides a minimum magnetic core in an axial gap type rotating electrical machine in which a winding stator is disposed on one side of a rotor in the direction of the rotation axis and a non-winding stator is disposed on the other side. It is an object to reduce the influence of the demagnetizing field acting on the permanent magnet of the rotor as much as possible.

  In order to solve the above-mentioned problem, this axial gap type rotating electrical machine is disposed so as to be rotatable about a rotating shaft (28a), and magnetic pole surfaces (21a, 21b) are provided around the rotating shaft on both surfaces in the rotating shaft direction. A substantially disk-shaped first back yoke magnetic core (32, 732) disposed on one side of the rotor in the direction of the rotation axis with a gap, and the back yoke magnetic core A plurality of cores (34) disposed on the rotor (20, 520) side of the core around the rotation axis and a surface facing the rotor (20, 520) of the core. A winding stator (30, 730) having a coil (36) wound around the core core or the back yoke magnetic core (32, 732) to generate a magnetic field, and the back yoke magnetic core Times A winding stator (30, 730) having a plurality of cores (34) disposed around the axis and a coil (36) wound around the core, and the direction of the rotation axis The non-winding stator (40, 640, 740) is disposed on the other side of the rotor with a gap and substantially has only a substantially disc-shaped second back yoke magnetic core (42, 642, 742). The rotor includes a permanent magnet (22, 122, 222, 322, 422, 522) and a rotor magnetic core (24, 524) disposed only on the winding stator side of the permanent magnet. ).

  In this case, the rotor may include the permanent magnet (122) having anisotropy having an easy axis of magnetization along the rotation axis direction.

  Alternatively, the rotor includes a plurality of permanent magnets (222) along the rotation axis, and the permanent magnet (222) is arranged along the circumferential direction around the rotation axis with the non-winding. It may have an anisotropy having an easy axis that is concentrated in the center toward the gap on the side or toward the non-winding stator side than the gap on the non-winding side.

  Further, the rotor has a plurality of permanent magnets (322) around the rotation axis, and the permanent magnet has a large thickness at a substantially central position along a circumferential direction around the rotation axis, The thickness may become smaller toward the both end portions.

  Further, the rotor has a plurality of permanent magnets (422) along the circumference of the rotation axis, and the dimension of the permanent magnet in the radial direction with respect to the rotation axis is large at a substantially central portion in the circumferential direction of the permanent magnet. , It may be small toward both ends thereof.

  The rotor has a plurality of permanent magnets (522) arranged at intervals around the rotation axis, and is magnetically independent between the permanent magnets. An intervening magnetic core (528) may be interposed.

  Moreover, you may comprise as a compressor (80) provided with one of the above-mentioned axial gap type rotary electric machines.

  In this case, a compression mechanism portion (90) that performs a compression operation in response to the rotational drive of the axial gap type rotating electrical machine is provided, and the rotation shaft portion (28) of the rotor is substantially only the compression mechanism portion. The non-winding stator (40) may be provided on the compression mechanism portion side with respect to the rotor (20).

  The winding stator side end of the rotating shaft portion (28) of the rotor is provided at a position that does not penetrate the winding stator (30), and a wiring portion ( 37) may be provided inside the core core (34).

  The inner diameter of the first back yoke magnetic core (732) of the winding stator (730) is smaller than the inner diameter of the second back yoke magnetic core (742) of the non-winding stator (740), and the winding The thickness of the first back yoke magnetic core (732) of the stator (730) in the rotational axis direction is smaller than the thickness of the second back yoke magnetic core (742) of the non-winding stator (740) in the rotational axis direction. May be.

  According to this axial gap type rotating electrical machine, the winding stator disposed with a gap on one side of the rotor in the rotation axis direction, and the gap on the other side of the rotor in the rotation axis direction. Since the provided non-winding stator is provided, the magnetic attractive force acting in the axial direction can be canceled as much as possible while suppressing an increase in the number of coils. Further, in such an axial gap type rotating electric machine, the rotor is excited because it has a permanent magnet and a rotor magnetic core disposed only on the winding stator side of the permanent magnet. Even if a demagnetizing field acts on the rotor by the external magnetic field of the wound stator, the influence of the demagnetizing field acting on the permanent magnet by the rotor core can be mitigated. On the other hand, since the non-winding stator is not excited, the influence of the demagnetizing field does not matter even if a rotor magnetic core is not provided on the non-winding stator side.

  In addition, when the rotor includes the permanent magnet having anisotropy having an easy magnetization axis along the rotation axis direction, the rotor can be strongly magnetized along the rotation axis direction, and the winding stator side and the non-winding side can be magnetized. Magnetic flux leakage can be reduced in both gaps on the wire stator side.

  Further, the permanent magnet is directed toward the non-winding side gap, or toward the non-winding stator side rather than the non-winding side gap, along the circumferential direction around the rotation axis. If the anisotropy has an easy axis concentrated in the approximate center, the magnetic flux density distribution is made sinusoidal at the gap on the non-winding stator side to reduce iron loss in the non-winding stator. be able to.

  Further, if the permanent magnet has a large thickness at the center along the circumferential direction centering on the rotation axis and decreases toward the both ends, the gap on the non-winding stator side By making the magnetic flux density distribution sinusoidal, iron loss in the non-winding stator can be reduced, and cogging generated between the winding stator and the winding stator can be reduced.

  Further, even if the size of the permanent magnet in the radial direction with respect to the rotating shaft is large at the substantially central portion in the circumferential direction of the permanent magnet and decreases toward both ends, the gap on the non-winding stator side By making the magnetic flux density distribution sinusoidal, iron loss in the non-winding stator can be reduced, and cogging generated between the winding stator and the winding stator can be reduced.

  In addition, when an intervening magnetic core that is magnetically independent from each permanent magnet is interposed between the permanent magnets, reluctance torque can be used together by using the intervening magnetic core.

  Moreover, the magnetic attraction force acting in the axial direction can be canceled as much as possible while the increase in the number of coils is suppressed by the compressor including any of the above-described axial gap type rotating electrical machines. Moreover, the influence of the demagnetizing field acting on the permanent magnet can be effectively reduced.

  Further, when the non-winding stator is provided on the compression mechanism portion side with respect to the rotor, it is possible to easily connect the coils of the winding stator and lead out the lead wires.

  In addition, the winding stator side end of the rotating shaft portion of the rotor is provided at a position not penetrating the winding stator, and the cross wiring portion of each coil is formed of the core core. If it is provided on the inner side, the crossover line can be shortened, made compact, and the like.

  Further, the inner diameter of the first back yoke magnetic core of the winding stator is smaller than the inner diameter of the second back yoke magnetic core of the non-winding stator, and the rotation axis of the first back yoke magnetic core of the winding stator. By making the thickness in the direction smaller than the thickness of the second back yoke magnetic core of the non-winding stator in the rotational axis direction, the magnetic path cross-sectional areas of both back yoke magnetic cores can be made the same.

{First embodiment}
Hereinafter, the axial gap type rotating electrical machine according to the first embodiment will be described. FIG. 1 is an exploded perspective view showing the rotating electrical machine according to the first embodiment, FIG. 2 is a side view showing the rotating electrical machine, and FIG. 3 is a perspective view showing the rotating electrical machine. FIG. 4 is a sectional view conceptually showing the rotating electric machine.

  The axial gap type rotating electrical machine 10 includes one rotor 20 and two stators 30 and 40. The rotor 20 is formed in a substantially disk shape, and the stators 30 and 40 are also formed in a substantially disk shape. The two stators 30 and 40 are disposed on both sides of the rotor 20. One of the stators 30 and 40 is a winding stator 30 having a coil 36, and the other is a non-winding stator 40 having no winding.

  Each part will be described in more detail.

  The rotor 20 is rotatably arranged around a predetermined rotation shaft 28a via a rotation shaft portion 28 (see FIG. 4). The rotating shaft 28a is rotatably supported by a bearing 29 (see FIG. 4). The rotor 20 has magnetic pole surfaces 21a and 21b having alternating magnetism around the rotation shaft 28a on both surfaces of the rotation shaft 28a.

  More specifically, the rotor 20 has a plurality of permanent magnets 22. More specifically, a plurality of permanent magnets 22 are provided around the rotation shaft 28a at intervals. Each permanent magnet 22 is formed in a shape obtained by dividing a donut plate-like member around the rotation shaft 28a into a plurality (eight in this case), that is, an arc-like and strip-like plate shape extending around the rotation shaft 28a. Each permanent magnet 22 is magnetized in the direction along the rotation axis 28 a, that is, in the thickness direction of the permanent magnet 22. Further, these permanent magnets 22 are arranged so as to exhibit annular and alternating magnetic poles around the rotating shaft 28a. With these permanent magnets 22, magnetic pole surfaces 21 a and 21 b that form magnetic poles with respect to the stators 30 and 40 are formed on both surfaces of the rotor 20.

  Further, the rotor magnetic core 24 is provided only on one surface of each permanent magnet 22, that is, on the surface on the winding stator 30 side. Each rotor magnetic core 24 is formed in an arc-like and strip-like plate shape corresponding to the shape of each permanent magnet 22, and is arranged on one surface of the permanent magnet 22 in a superposed manner.

  As a result, when a demagnetizing field acts on the rotor 20 by the external magnetic field of the excited winding stator 30, the influence of the demagnetizing field acting on each permanent magnet 22 is mitigated by each rotor core 24. The permanent magnets 22 are prevented from demagnetizing.

  On the other hand, since the non-winding stator 40 is not excited, it is not necessary to consider the demagnetizing field from the non-winding stator 40, so that the permanent magnet 22 is directly connected to the non-winding stator 40 side of the rotor 20. There is no problem even if it is exposed. For this reason, the rotor magnetic core is not provided in the non-winding stator 40 side which is the other surface of each permanent magnet 22 here.

  The rotor magnetic core 24 is preferably made of a material having high resistivity, for example, a dust core. This is due to the following reason. That is, if each permanent magnet 22 is made of a material having a low resistivity, such as a sintered rare earth magnet, and the rotor magnetic core 24 is also made of a material having a low resistivity, these permanent magnets 22 and the rotor cores are made. The effect of reducing the eddy current generated at 24 cannot be expected so much. However, if the rotor magnetic core 24 is made of a material having a high resistivity, an effect of reducing eddy current generated in the rotor magnetic core 24 can be expected. In particular, for example, the magnetic flux of the carrier high frequency component generated by the winding stator 30 by the PWM inverter drive hardly acts to the permanent magnet 22, and the eddy current due to the magnetic flux is generated near the surface of the rotor core 24 by the skin effect. Easy to do. Therefore, by forming the rotor core 24 from a material having a high resistivity, such eddy currents of high frequency components can be effectively reduced. Reduction of the eddy current loss of the permanent magnet has an effect of preventing thermal demagnetization due to heat generation of the permanent magnet in addition to reduction of iron loss.

  The permanent magnets and the rotor magnetic cores 24 are held in the above-described arrangement by a holder 26 formed of a nonmagnetic material and are fixed to the rotary shaft portion 28 (see FIG. 4). 1-3, illustration of the holder 26 and the rotating shaft part 28 is abbreviate | omitted.

  The two stators 30 and 40 are disposed on both sides of the rotor 20 in the direction of the rotation shaft 28a so as to face the rotor 20 with a gap (here, a slight gap) therebetween. The stators 30 and 40 are fixed to a casing or the like (not shown).

  One winding stator 30 has a first back yoke magnetic core 32, a plurality of cores 34, and a plurality of coils 36.

  The first back yoke magnetic core 32 is made of a magnetic material, and is formed in a substantially disk shape with a hole 32h formed in a substantially central portion. The hole 32h is not essential when the end of the rotary shaft 28 is provided at a non-penetrating position of the winding stator as will be described later. The first back yoke magnetic core 32 may be formed of any one of a dust core and a laminated steel plate. The first back yoke magnetic core 32 supports the core core 34 on the side opposite to the rotor 20.

  Each of the cores 34 is annularly arranged on the surface of the first back yoke core 32 on the rotor 20 side at intervals along the circumferential direction around the rotation shaft 28a. Each of the cores 34 is formed in a plate shape having a shape obtained by rounding the vertices of an isosceles triangle in a plane substantially orthogonal to the rotation shaft 28a, and becomes gradually wider outwardly from the rotation shaft 28a. It is arranged in a posture. The core core 34 may be formed of any one of a dust core, a laminated steel plate, and the like. Note that the cores 34 adjacent to each other in the circumferential direction are substantially equidistant.

Each coil 36 is wound around each core core 34. In addition, the cross wiring part 37 which connects each coil 36 is provided in the part at the approximate center part of the 1st back yoke magnetic core 32, and the rotor 20 side. Further, the external wiring 37a from the cross wiring section 37 is drawn to the outside through the hole 32h. The rotating shaft portion 28 is inserted into the shaft insertion hole portion 42 h of the non-winding stator 40 and rotatably supports the rotor 20, and has a length that does not reach the winding stator 30. Therefore, a space for connection can be provided in a substantially central portion of the first back yoke magnetic core 32 and a portion on the rotor 20 side.
In addition, the cross wiring part 37 which connects each coil 36 may be provided in the outer peripheral side of each core magnetic core 34 and the coil 36, and the external wiring 37a from this cross wiring part 37 is also the 1st back yoke magnetic core 32. Or a notch or the like provided on the outer side of the first back yoke magnetic core 32.

  Further, in this winding stator 30, a wide magnetic core 38 is provided on the surface of each core core 34 on the rotor 20 side. Each of the wide magnetic cores 38 is formed in a plate-like member having a larger extent (here, one size larger) than the core core 34 in a plane substantially orthogonal to the rotation shaft 28a, and rotates with the main winding stator 30. It functions to increase the facing area with the child 20. Each wide magnetic core 38 is connected to the inner peripheral side and the outer peripheral side of the winding stator 30 by a connecting portion 38a so that all the wide magnetic cores 38 can be handled as a single body. However, the connecting portion 38a is formed so as to have a sufficiently small cross-sectional area such as being thinned so that the magnetic saturation is easily performed between the wide magnetic cores 38. , Magnetically independent. The wide magnetic core 38 can improve the magnetic flux density between the rotor 20 and the winding stator 30. Further, by increasing the flatness of the winding stator 30 with respect to the rotor 20, the substantial gap length between the rotor 20 and the winding stator 30 can be further reduced. In addition, the connection part 38a is not essential, and each wide magnetic core 38 is not necessarily required.

  The non-winding stator 40 substantially has only a substantially disc-shaped second back yoke magnetic core 42. Here, the fact that the non-winding stator 40 substantially has only the second back yoke magnetic core 42 means that it has no element related to the generation of an electric magnetic field such as a coil.

  The second back yoke magnetic core 42 is formed in a substantially disk shape, and a shaft insertion hole portion 42h through which the rotary shaft portion 28 can be inserted is formed in a substantially central portion thereof. The second back yoke magnetic core 42 may be formed of any one of a dust core, a laminated steel plate, and the like. The bearing may extend to the shaft insertion hole 42h, and the bearing may be held in the shaft insertion hole 42h.

  The axial gap type rotating electrical machine 10 is driven by, for example, a three-phase inverter.

  The axial gap type rotating electrical machine 10 configured as described above has a configuration in which two stators 30 and 40 are provided on both sides of one rotor 20 along the direction of the rotation axis 28a. Compared to the configuration in which two elements are provided, the bearing configuration can be simplified and the rotating shaft portion can be shortened, and torsional vibration of the rotating shaft portion can be prevented.

  On the premise of such a configuration, a winding stator 30 and a non-winding stator 40 are disposed on both sides of the rotor 20 in the direction of the rotary shaft 28a, and the winding stator 30 and the non-winding stator are arranged. 40 forms a common magnetic circuit via the rotor 20, the amount of magnetic flux passing through the gap on both sides of the rotor 20 is substantially the same. As a result, the magnetic attractive force acting in both gaps is canceled as much as possible, and the strut force acting on the rotor 20 and the rotating shaft portion 28 can be reduced. Thereby, bearing loss can be reduced and bearing life can be extended.

  Of the two stators 30, 40, only one winding stator 30 has the coil 36, and the non-winding stator 40 practically has only the second back yoke magnetic core 42. Therefore, an increase in the number of coils can be suppressed.

  Further, since the rotor 20 has a rotor magnetic core 24 disposed only on the winding stator 30 side of each permanent magnet 22, a minimum magnetic core is provided on the rotor so that the winding is fixed. The influence on each permanent magnet 22 by the demagnetizing field of the child 30 can be reduced.

  On the other hand, since the non-winding stator 40 is not excited, no rotor magnetic core is provided on the non-winding stator 40 side, which is the other surface of each permanent magnet 22. For this reason, thickness reduction of the rotor 20 can be achieved.

  The basic configuration of this axial gap type rotating electrical machine is as described above. In the following, a preferred specific configuration or a preferred modification will be described on the basis of the above configuration. In the following description, elements similar to those described above are denoted by the same reference numerals and description thereof is omitted.

  First, the gap length on both sides of the rotor 20 in the direction of the rotating shaft 28a will be described. As for the gap lengths on both sides, by adopting the smallest dimension that can be machined and making both gap lengths substantially the same, the magnetoresistance can be minimized at both gaps. Thereby, an operating point magnetic flux density can be improved and the energy of the permanent magnet 22 can be utilized effectively. However, since the non-winding stator 40 has substantially only the second back yoke magnetic core 42, the non-winding stator 40 is finally finished with fewer errors in terms of processing accuracy and assembly accuracy than the winding stator 30. . Therefore, in practice, the gap length between the non-winding stator 40 and the rotor 20 can be made smaller than the gap length between the winding stator 30 and the rotor 20, and such It may be a configuration.

  However, in the winding stator 30, slits are formed between the wide magnetic cores 38 to prevent magnetic flux leakage between the cores 34. For this reason, the area where the winding stator 30 faces the rotor 20 is smaller than the area where the non-winding stator 40 faces the rotor 20.

  For this reason, in consideration of permeance in each gap, it is preferable to make the gap length on the winding stator 30 side smaller than the gap length on the non-winding stator 40 side.

  Further, even if attention is paid to the magnetic attractive force in both gaps, if the gap lengths are the same, the magnetic attractive force acting between the winding stator 30 and the rotor 20 due to the difference in facing area is as follows. The magnetic attractive force acting between the non-winding stator 40 and the rotor tends to be smaller. For this reason, in order to make the magnetic attraction forces in both gaps as much as possible, the gap length on the winding stator 30 side is made smaller than the gap length on the non-winding stator 40 side, as described above. Is preferred.

  For these reasons, in order to cancel the magnetic attractive force in both gaps as much as possible and to reduce the thrust force of the rotor 20 and the rotary shaft portion 28, the gap length on the winding stator 30 side is set to a non-winding. It is more preferable to make it smaller than the gap length on the stator 40 side.

  Next, the form of the rotor 20 will be described. FIG. 5 is a plan view showing one permanent magnet provided on the rotor and the rotor magnetic core provided on one surface thereof, and FIG. 6 is cut along the circumferential direction of the circle centering on the rotation axis in FIG. It is the VI-VI sectional view taken on the line.

  The permanent magnet 122 corresponding to the permanent magnet 22 is formed by magnetizing an anisotropic magnetic material having an easy magnetization axis along the direction of the rotation axis 28a along the direction of the rotation axis 28a.

  As a result, the permanent magnet 122 can be strongly magnetized along the direction of the rotating shaft 28a, and magnetic flux leakage can be reduced in the gaps on both the winding stator 30 and the non-winding stator 40 side. There are advantages.

  FIG. 7 is a view showing a modification of the permanent magnet. FIG. 7 is a cross-sectional view showing a portion cut along the same circumferential direction as FIG.

  In FIG. 7, the permanent magnet 222 corresponding to the permanent magnet 22 is easily magnetized so as to be concentrated in the substantially center toward the gap on the non-winding stator 40 side along the circumferential direction of the circle centered on the rotation shaft 28 a. It is formed by magnetizing an anisotropic magnetic material having an axis along the direction of the rotation axis 28a. Here, the reference circle may be any circle that has the rotation axis 28a as the center and passes through all the permanent magnets 222, and is, for example, a circle that passes through the radial center of the permanent magnet 222. Note that the concentrated points do not necessarily have to be in the gap, that is, the easy axis of magnetization may be concentrated substantially in the center toward the non-winding stator 40 side portion rather than the non-winding side gap.

  In the example shown in FIG. 7, the magnetic flux density distribution can be made sinusoidal along the circumferential direction of the circle centered on the rotation shaft 28a by the gap on the non-winding stator 40 side. Thereby, the iron loss can be reduced by converting the change in the magnetic flux density in the second back yoke magnetic core 42 of the non-winding stator 40 into a sine wave and reducing the harmonic magnetic flux.

  FIG. 8 is a diagram showing another modification of the permanent magnet. FIG. 8 is a cross-sectional view showing a portion cut along the same circumferential direction as FIG.

  In FIG. 8, the permanent magnet 322 corresponding to the permanent magnet 22 has a large thickness along the circumferential direction of the circle centering on the rotating shaft 28a, and is thin at the center in the circumferential direction, and decreases in thickness toward both ends. It is formed to become. At the same time, the length of the air gap between the permanent magnet 322 and the non-winding stator is small at the center in the circumferential direction, and increases as it goes toward both ends.

  FIG. 9 is a perspective view showing still another modification of the permanent magnet, and FIG. 10 is a plan view showing the permanent magnet according to the modification and the rotor magnetic core provided on one surface thereof.

  In the modification shown in FIGS. 9 and 10, the permanent magnet 422 corresponding to the permanent magnet 22 is such that the dimensions a1 and a2 of the permanent magnet 422 in the radial direction with respect to the rotating shaft 28a are substantially at the center in the circumferential direction of the permanent magnet 422. Larger (a1) and smaller toward both ends (a2).

  8 and the modification examples shown in FIGS. 9 and 10, the magnetic flux density distribution in the gap on the non-winding stator 40 side is also changed in the circumferential direction of the circle centering on the rotation axis 28a. It is possible to reduce the iron loss in the non-winding stator 40 by making it sinusoidal along the sine wave, and also to reduce cogging by making the magnetic flux density distribution generated on the winding stator side of the rotor sinusoidal. Can be reduced. Considering only the cogging torque, the rotor magnetic core 24 can also have the same shape as the permanent magnet 22 or a similar shape.

  Note that the magnetic flux density distribution in the gap may be set closer to a sine wave by appropriately combining the above modifications.

  Next, the structure which fixes a permanent magnet and a rotor magnetic core is demonstrated.

  That is, as the holder 26, the permanent magnet 22 and the rotor magnetic core 24 arranged at fixed positions are molded with a holder material such as a resin, or a recessed portion for receiving is formed in a separately formed holder. A configuration in which the permanent magnet 22 and the rotor magnetic core 24 are fixed to each other is conceivable.

  FIG. 11 is a view showing a modification of the holder for fixing the permanent magnet and the rotor magnetic core.

  The holder 126 corresponding to the holder 26 is made of, for example, a nonmagnetic metal, is coupled to the rotary shaft portion 28, and holds the permanent magnet 22 and the rotor magnetic core 24 in an embedded state. Further, the holding holes 126h of the holder 126 are formed with step portions 126ha and 126hb that can come into contact with the peripheral portion of the permanent magnet 22 or the rotor magnetic core 24. Then, the permanent magnet 22 and the rotor magnetic core 24 are arranged in a stepped shape (here, stepped along the radial direction of a circle centering on the rotation shaft 28a) in the holding hole 126h, and one stepped portion 126ha. Is held in contact with the peripheral edge of the inner surface of the permanent magnet 22 and the other stepped portion 126hb is held in contact with the peripheral edge of the inner surface of the rotor magnetic core 24. Thereby, the permanent magnet 22 and the rotor magnetic core 24 can be accurately held at a fixed position.

  FIG. 12 is a diagram illustrating an example in which an intervening magnetic core is provided in the rotor.

  In other words, the rotor 520 has a plurality (four in this case) of permanent magnets 522 disposed around the rotation shaft 28a with a space therebetween. A rotor magnetic core 524 is provided on the surface of each permanent magnet 522 on the winding stator 30 side. Further, the rotor 520 has intervening magnetic cores 528 that are magnetically independent of the permanent magnets 522 between the permanent magnets 522. The intervening magnetic core 528 faces both the winding stator 30 and the non-winding stator 40. That is, the permanent magnets 522 and the intervening magnetic cores 528 are annularly and alternately arranged around the rotation shaft 28a. Each permanent magnet 522 and the intervening magnetic core 528 are held in a magnetically independent state by a holder 526 formed of a non-magnetic material. As the intervening magnetic core 528, it is preferable to use an isotropic soft magnetic material such as a dust core. In FIG. 2, the holder 526 is partially cut away for easy understanding.

  By providing the intervening magnetic core 528, the q-axis inductance Lq indicating the gap can be made larger than the d-axis inductance Ld indicating the center of the permanent magnet 22, and the reverse saliency (Lq> Ld) is exhibited. . For this reason, by controlling the current phase with an appropriate advance angle with respect to the q axis, so-called reluctance torque can be further added to so-called magnet torque, and torque and energy efficiency can be increased.

  The rotating electrical machine 10 can be applied not only as an electric motor (motor) but also as a generator.

{Second Embodiment}
Hereinafter, the compressor according to the second embodiment will be described. FIG. 13 is a sectional view showing a compressor to which a motor as the axial gap type rotating electrical machine is applied.

  The compressor 80 is a so-called high-pressure dome type compressor, and includes a rotary electric machine 10 and a compression mechanism 90 in a substantially cylindrical sealed container 82 as a casing. An oil reservoir 83 is provided at the lower part of the sealed container 82.

  The compression mechanism 90 compresses the refrigerant supplied from the suction pipe 91 by driving the rotating electrical machine 10, and discharges the compressed high-pressure refrigerant from the discharge pipe 92.

  The rotating electrical machine 10 has the same configuration as that described with reference to FIGS. 1 to 4 in the first embodiment. The rotating electrical machine 10 drives the compression mechanism unit 90 via the rotating shaft unit 28 (shaft). The first back yoke magnetic core is fixed to the inside of the sealed container 82 by welding or the like at the outer periphery. Similarly, the second back yoke is fixed to the inside of the sealed container 82 at the outer peripheral portion by welding or the like, but may be fixed by unscrewing a pin or the like from the upper end surface of the compression mechanism portion.

  The rotating electrical machine 10 is provided in the high-pressure region H in which the high-pressure refrigerant gas is filled in the sealed container 82, here, on the upper side of the compression mechanism unit 90. That is, the compressor 80 is in a vertically placed form.

  The installation configuration of the rotating electrical machine 10 will be described. The rotating electrical machine 10 is arranged in a posture in which the rotating shaft portion 28 is aligned with the central axis of the sealed container 82. In addition, the winding stator 30 is disposed on the side farther from the compression mechanism 90 than the rotor 20, and the non-winding stator 40 is closer to the compression mechanism 90 than the rotor 20. It is arranged.

  Further, the rotary shaft portion 28 connected to the rotor 20 passes through the non-winding stator 40 and is connected to the compression mechanism portion 90. Then, the rotational motion of the rotor 20 is transmitted to the compression mechanism 90 via the rotary shaft portion 28. Note that the rotary shaft portion 28 does not penetrate the winding stator 30, that is, the rotary shaft portion 28 and the rotor 20 are substantially one-side support structure that is held only on the compression mechanism portion 90 side. Has been. As described in the first embodiment, since the rotating shaft portion 28 is shortened, the influence of the inclination of the rotating shaft portion 28 is small even in such a one-side support structure.

  Further, in this compressor 80, the end of the rotary shaft portion 28 is in a position not penetrating the winding stator 30, that is, on the rotor 20 side with respect to the winding stator 30, so the winding stator 30 Among them, a space for wiring can be secured in a portion from the center of each coil 36. Therefore, a cross wiring portion 37 for connecting the coils 36 to each other is provided inside the core core 34. Further, the external wiring 37a from the cross wiring section 37 is drawn to the outside through the hole 32h at the substantially center of the winding stator 30 (see also FIG. 4).

  The compressor 80 configured as described above has the same effect as that of the first embodiment.

  Moreover, the rotation shaft portion 28 of the rotor 20 is substantially maintained only by the compression mechanism portion 90, and the non-winding stator 40 is provided on the compression mechanism portion 90 side with respect to the rotor 20. Therefore, the rotor 20 can be further shortened.

  Furthermore, since the cross wiring portion 37 is provided inside the core core 34, the cross wire can be shortened and the rotating electrical machine 10 can be made compact. Further, since the wiring to the outside can be concentrated and pulled out from the winding stator 30, the wiring work can be facilitated and the external wiring can be made compact.

  The basic configuration of the compressor is as described above. Below, a preferable modification is demonstrated on the assumption of the said structure. In the following description, elements similar to those described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 14 is a view showing a modification of the non-winding stator. A non-winding stator 640 according to this modification (corresponding to the non-winding stator 40) includes a second back yoke magnetic core 642 (the second back) having a laminated steel plate portion 642a and a dust core ring portion 642b. Corresponding to the yoke magnetic core 42).

  The laminated steel plate portion 642a is formed of a laminated steel plate in which sufficiently strong steel plates are laminated in the direction of the rotation axis 28a. The laminated steel plate portion 642a is formed in a substantially disk shape having the same outer peripheral shape as the second back yoke magnetic core 42, and an annular recess 642ah is formed in an annular portion of the rotor 20 facing each permanent magnet 22. Has been.

  The dust core ring portion 642b is formed of a dust core and is formed in a ring shape that can be fitted into the annular recess 642ah. The dust core ring portion 642b is fitted and fixed to the annular recess 642ah by shrink fitting, welding, or the like.

  In this modified example, the laminated steel plate portion 642a can obtain the strength required to fix and hold the non-winding stator 640 in the sealed container 82. On the other hand, when the laminated steel plate faces the rotor 20, the magnetic resistance is increased due to the gap between the layers and the insulating film when the magnetic flux is exchanged with the rotor 20. Therefore, as described above, an increase in magnetic resistance is prevented by using the dust core ring portion 642b.

  FIG. 15 is a cross-sectional view showing a modification of the compressor. Here, the inner diameter b1 of the first back yoke magnetic core 732 (corresponding to the first back yoke magnetic core 32) of the winding stator 730 (corresponding to the winding stator 30) is defined as the non-winding stator 740 (non-winding stator 740). It is smaller than the inner diameter b2 of the second back yoke magnetic core 742 (corresponding to the second back yoke magnetic core 42) of the wire stator 40). Further, the thickness dimension c1 of the first back yoke magnetic core 732 of the winding stator 730 is made smaller than the thickness dimension c2 of the second back yoke magnetic core 742 of the non-winding stator 740.

  That is, since the non-winding stator 740 has no coil, there are few restrictions on the shape, so that the inner diameter of the shaft insertion hole 742h can be increased as described above. When the inner diameter of the shaft insertion hole 742h is increased in this manner, the magnetic path cross-sectional area at the second back yoke magnetic core 742 is reduced. Therefore, the thickness of the second back yoke magnetic core 742 may be relatively large, that is, greater than the thickness of the first back yoke magnetic core 732. Accordingly, the magnetic path cross-sectional areas of both the back yoke magnetic cores 732 and 742 can be made the same without making the first back yoke magnetic core 732 thicker than necessary and increasing the material used. In order to increase the inner diameter of the shaft insertion hole 742h of the non-winding stator 740, it is necessary to insert the thick rotating shaft portion 28 necessary to connect the load (compression mechanism portion) and the rotor. Will inevitably be required. Further, the second back yoke magnetic core 742 of the non-winding stator 740 may be a magnetic steel sheet laminated in the radial direction, for example, wound. In that case, in order to reduce the number of windings, a configuration in which the dimension b1 is smaller than the dimension b2 and the dimension c1 is smaller than the dimension c2 is desirable.

It is a disassembled perspective view which shows the rotary electric machine which concerns on 1st Embodiment. It is a side view which shows a rotary electric machine same as the above. It is a perspective view which shows a rotary electric machine same as the above. It is sectional drawing which shows notionally a rotary electric machine same as the above. It is a top view which shows one permanent magnet provided in a rotor, and the rotor magnetic core provided in this one surface. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is sectional drawing which shows the modification of a permanent magnet. It is sectional drawing which shows the other modification of a permanent magnet. It is a perspective view which shows the other modification of a permanent magnet. It is a top view which shows the permanent magnet which concerns on the modification same as the above, and the rotor magnetic core provided in the one surface. It is a figure which shows the modification of the holder which fixes a permanent magnet and a rotor magnetic core. It is a figure which shows the example which provided the interposition magnetic core in the rotor. It is sectional drawing which shows a compressor. It is a figure which shows the modification of a non-winding stator. It is sectional drawing which shows the modification of a compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Axial-gap-type rotary electric machine 20,520 Rotor 21a, 21b Magnetic pole surface 22,122,222,322,422,522 Permanent magnet 24,524 Rotor core 28 Rotating shaft part 28a Rotating shaft 30,730 Winding stator 32 , 732 First back yoke magnetic core 32h Hole 34 Core core 36 Coil 37 Cross wiring 40, 640, 740 Non-winding stator 42, 642, 742 Second back yoke magnetic core 42h, 742h Shaft insertion hole 80 Compressor 90 Compression mechanism 528 Intervening magnetic core

Claims (10)

A rotor (20, 520) that is rotatably arranged around the rotation axis (28a) and presents magnetic pole faces (21a, 21b) around the rotation axis on both sides in the rotation axis direction;
A substantially disc-shaped first back yoke magnetic core (32, 732) disposed on one side of the rotor in the direction of the rotation axis, and the rotor (20, 520) side of the back yoke magnetic core A plurality of cores (34) disposed along the circumference of the rotation axis, and the core to generate a rotating magnetic field on a surface facing the rotor (20, 520) of the core. A winding stator (30, 730) having a magnetic core or a coil (36) wound around the back yoke magnetic core (32, 732);
A non-winding stator (40, having only a substantially disc-shaped second back yoke magnetic core (42, 642, 742) disposed on the other side of the rotor in the direction of the rotation axis with a gap therebetween. 640, 740),
With
The rotor includes a permanent magnet (22, 122, 222, 322, 422, 522) and a rotor magnetic core (24, 524) disposed only on the winding stator side of the permanent magnet. Axial gap type rotating electrical machine (10). The axial gap type rotating electrical machine according to claim 1,
The rotor includes an axial gap type rotating electric machine including the permanent magnet (122) having anisotropy having an easy axis of magnetization along the rotation axis direction. The axial gap type rotating electrical machine according to claim 1,
The rotor has a plurality of permanent magnets (222) around the rotation axis;
The permanent magnet (222) is directed toward the non-winding side gap or toward the non-winding stator side from the non-winding side gap along the circumferential direction around the rotation axis. An axial gap type rotating electrical machine having anisotropy with an easy axis of magnetization concentrated in the center. It is an axial gap type rotary electric machine in any one of Claims 1-3,
The rotor has a plurality of permanent magnets (322) around the rotation axis;
An axial gap type rotating electrical machine in which the permanent magnet has a large thickness at a substantially central position along a circumferential direction around the rotation axis, and a smaller thickness toward both ends thereof. It is an axial gap type rotary electric machine in any one of Claims 1-4,
The rotor has a plurality of permanent magnets (422) around the rotation axis;
An axial gap type rotating electrical machine in which the dimension of the permanent magnet in the radial direction with respect to the rotating shaft is large at a substantially central portion in the circumferential direction of the permanent magnet and small toward both ends thereof. An axial gap type rotating electrical machine according to any one of claims 1 to 5,
The rotor has a plurality of permanent magnets (522) arranged at intervals around the rotation axis,
An axial gap type rotating electrical machine in which an intervening magnetic core (528) is interposed between the permanent magnets, which is magnetically independent from the permanent magnets.   The compressor (80) provided with the axial gap type rotary electric machine in any one of Claims 1-6. The compressor according to claim 7, wherein
A compression mechanism (90) that receives a rotational drive of the axial gap type rotating electrical machine and performs a compression operation;
The said non-winding stator (40) is a compressor provided in the said compression mechanism part side with respect to the said rotor (20). The compressor according to claim 8, wherein
The winding stator side end portion of the rotating shaft portion (28) of the rotor is provided at a position that does not penetrate the winding stator (30), and the wiring portion (37) between the coils. Is a compressor provided inside the core core (34). A compressor according to claim 7 or claim 8, wherein
The inner diameter of the first back yoke magnetic core (732) of the winding stator (730) is smaller than the inner diameter of the second back yoke magnetic core (742) of the non-winding stator (740),
The thickness of the first back yoke magnetic core (732) of the winding stator (730) in the rotational axis direction is the same as that of the second back yoke magnetic core (742) of the non-winding stator (740). Compressor smaller than thickness.

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