JP2008220128A - Axial gap type rotary electric machine and compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress cogging torque as much as possible in an axial gap type rotary electric machine in which a winding stator is disposed on one side of a rotor in a rotary shaft direction and a non-winding stator is disposed on the other side. <P>SOLUTION: A winding stator 30 and a non-winding stator 40 are disposed on both the sides of a single rotor 20 along a rotary shaft direction 28a. A groove 38S is formed on the winding stator 30 side, and a non-winding staotor side concave portion 42S is formed on the non-winding stator 40 side. The concave portion 42S is formed on a position outside the position where the groove 38S as the non-winding stator side concave portion is projected along the rotary shaft 28a. <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, the auxiliary yoke core of the auxiliary yoke is formed at a position facing each stator core of the stator. For this reason, the slits between the cores are formed between the stator and the auxiliary yoke at positions facing each other across the rotor, and a relatively large cogging torque is generated when the rotor rotates.

  Therefore, the present invention suppresses cogging torque as much as possible in an axial gap type rotating electrical machine in which a winding stator is disposed on one side of the rotor in the rotation axis direction and a non-winding stator is disposed on the other side. The purpose is to do.

  In order to solve the above-mentioned problem, this axial gap type rotating electrical machine is disposed so as to be rotatable about a rotation axis, and a rotor presenting a plurality of magnetic poles around the rotation axis on both surfaces in the rotation axis direction, and the rotation A gap is disposed on one side of the rotor in the axial direction with a gap therebetween, and the first back yoke magnetic core having a substantially disc shape and the rotor side of the first back yoke magnetic core are disposed around the rotation axis. A plurality of stator magnetic cores, a winding stator having a coil that generates a rotating magnetic field on a surface of each of the stator cores facing the rotor, and the other side of the rotor in the direction of the rotation axis And a non-winding stator having only a substantially disc-shaped second back yoke magnetic core, and a portion on the rotor side of the winding stator. Between each stator core A winding stator side recess that is recessed with respect to the rotor is formed, and is a portion on the rotor side of the non-winding stator, and the winding stator side recess is projected along the rotation axis. A non-winding stator side recess extending along the radial direction of the non-winding stator is formed at a position deviated from the position.

  In this case, the winding stator side recess may be a groove between the respective stator magnetic cores or a groove between the wide magnetic cores attached to the front ends of the respective stator magnetic cores.

  The non-winding stator side recesses and the winding stator side recesses may be provided with substantially the same width, substantially the same interval, and the same number.

  In addition, an angle at which the extending direction of each non-winding stator side recess with respect to the extending direction of each winding stator side recess about the rotation axis is (180 ÷ Nc) ° (where Nc May be the least common multiple of the number of the respective stator cores of the winding stator and the number of magnetic poles appearing on one side of the rotor.

  Further, the rotor has a plurality of permanent magnets arranged at intervals around the rotation axis, and the intervening magnetic cores are magnetically independent from the permanent magnets between the permanent magnets. May be interposed.

  Moreover, the compressor which solves the said subject is equipped with one of said axial gap type rotary electric machines.

  In this case, a compression mechanism portion that performs a compression operation in response to the rotational drive of the axial gap type rotating electrical machine is provided, and the non-winding stator is provided on the compression mechanism portion side with respect to the rotor. Also good.

  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 the rotating shaft of the coil. It may be provided on the side.

  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. The thickness in the direction may be smaller than the thickness in the rotation axis direction of the second back yoke magnetic core of the non-winding stator.

  According to this axial gap type rotating electrical machine, a winding stator side recess that is recessed with respect to the rotor is formed between the stator cores on the rotor side of the winding stator, In the radial direction of the non-winding stator, in the rotor-side portion of the non-winding stator and at a position outside the position where the winding stator-side recess is projected along the rotation axis. When the non-winding stator side recess extending along the axis is formed, the winding stator is disposed on one side of the rotor in the rotation axis direction, and the non-winding stator is disposed on the other side. In the gap-type rotating electrical machine, the cogging torque can be suppressed as much as possible while making the magnetic circuit the same on the winding stator side and the non-winding stator side as much as possible.

  In addition, each of the non-winding stator side recesses and each of the winding stator side recesses are provided with substantially the same width, substantially the same interval, and the same number, and the winding stator side and the non-winding stator side The magnetic circuit can be made similar.

  Further, in the axial gap type rotating electrical machine, the basic waveform is the same as the least common multiple Nc of the number of the stator cores of the winding stator and the number of magnetic poles appearing on one side of the rotor per one rotation of the rotor. appear. Therefore, by setting the angle at which the extending direction of the non-winding stator side recess is shifted from the extending direction of the winding stator side recess about the rotation axis to (180 ÷ Nc) °, The basic waveform of the cogging torque can be reversed in phase between the winding stator side and the non-winding stator side, and the cogging torque can be more effectively suppressed.

  Further, when an intervening magnetic core that is magnetically independent from each permanent magnet is interposed between the permanent magnets, reluctance torque can be used in combination using the intervening magnetic core.

  The cogging torque can be suppressed as much as possible by the compressor including any of the above-described axial gap type rotating electrical machines.

  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 the rotating shaft of the coil. If it is provided on the 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 an axial gap type rotating electric machine according to the first embodiment, FIG. 2 is a perspective view showing the rotating electric machine, and FIG. It is a figure which shows the positional relationship with the winding stator side recessed part, and FIG. 4 is sectional drawing which shows notionally the rotary 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). In addition, the rotor 20 has a plurality of permanent magnets 22 around the rotation shaft 28a that have alternating magnetic poles around the rotation shaft 28a on both surfaces of the rotation shaft 28a. More specifically, each permanent magnet 22 is formed into a shape obtained by dividing a donut plate-like member around the rotation shaft 28a into a plurality (here, eight), that is, an arc-like and strip-like plate shape extending around the rotation shaft 28a. Are arranged with a space between them. Further, each permanent magnet 22 is magnetized in the direction along the rotation shaft 28a, that is, in the thickness direction of the permanent magnet 22, and is disposed so as to present an annular and alternating magnetic pole around the rotation shaft 28a. Yes.

  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. A rotor core may be provided on the non-winding stator 40 side, and the rotor core in this case has a role of protecting the permanent magnet 22.

  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, from the following viewpoint, it is preferable to use a neodymium sintered rare earth magnet for each permanent magnet 22. That is, neodymium-based rare earth magnets have a very high magnetic energy product, so that the axial gap type rotating electrical machine can be further miniaturized and high efficiency can be realized by reducing copper loss. However, if each permanent magnet 22 is made of a material having a low resistivity, such as a neodymium sintered rare earth magnet, and the rotor core 24 is also made of a material having a low resistivity, these permanent magnets 22 are made permanent. The effect of reducing the eddy current generated in the magnet 22 and the rotor core 24 cannot be expected so much. Therefore, by forming the rotor magnetic core 24 from 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. Further, particularly when the winding method of the winding stator 40 is concentrated winding, or when the current flowing through the winding is large, the current flowing through the winding does not directly act on the permanent magnet 22 and the rotor core. In some cases, not only the permanent magnets 22 but also the adjacent rotor magnetic cores 24 are caused to flow through 24 to have an effect of reducing the demagnetizing field acting on the permanent magnets 22. This is an effect that can be obtained regardless of the magnet material, but is particularly effective in the case of a ferrite-based magnet or a material having a relatively small coercive force, such as a bonded magnet, even in the case of a rare earth-based material.

  The permanent magnets 22 and the rotor magnetic cores 24 are held in the above arrangement by a holder 26 formed of a non-magnetic material and are fixed to the rotary shaft portion 28 (see FIG. 4). . In FIGS. 1 and 2, the holder 26 and the rotating shaft portion 28 are not shown. Since neodymium-based rare earth magnets have a high magnetic energy product, a large change in magnetic flux density occurs at the boundary between the magnetic poles, and the cogging torque tends to increase. In particular, in the case of a sintered product, since the degree of freedom of shape is relatively small, there is a limit to cogging countermeasures using only the magnet shape.

  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 includes a first back yoke magnetic core 32, a plurality of stator magnetic 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 stator magnetic core 34 on the side opposite to the rotor 20.

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

  Each coil 36 generates a rotating magnetic field on the surface of each stator core 34 that faces the rotor 20. Here, each coil 36 is wound around each stator 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 part 37 is drawn to the outside through the hole 32h and the like. 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. The winding form of each coil 36 is not necessarily the concentrated winding form as described above, and may be a distributed winding form or the like.

  In addition, the cross wiring part 37 which connects each coil 36 may be provided in the outer peripheral side of each stator magnetic core 34 and the coil 36, and the external wiring 37a from this cross wiring part 37 is also 1st back yoke magnetic core. It may be drawn to the outside through a notch or the like provided on the outside of 32 or the outside of the first back yoke magnetic core 32.

  In the winding stator 30, a wide magnetic core 38 is provided on the surface of the stator magnetic core 34 on the rotor 20 side. Each of the wide magnetic cores 38 is formed as a plate-like member (here, a substantially fan-like plate-like member) having a larger extent (here, one size larger) than the stator magnetic core 34 in a plane substantially orthogonal to the rotation shaft 28a. Thus, it functions to increase the facing area between the winding stator 30 and the rotor 20.

  Further, between each wide magnetic core 38, a groove 38S having a uniform width extending along the radial direction of a circle centering on the rotation shaft 28a is formed. The groove portions 38S are provided in the same number (12 in this case) as the stator magnetic cores 34, and are provided at substantially equal intervals along the rotation shaft 28a. Each groove 38S has a role of magnetically separating each wide magnetic core 38. Here, each of these groove portions 38 </ b> S is a portion on the rotor 20 side of the winding stator 30, formed between the stator magnetic cores 34, and formed as a winding stator-side recess recessed with respect to the rotor 20. Function.

  In addition, 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 disc 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.

  In addition, the non-winding stator 40 has a non-winding stator 40 side portion, and a groove 38S serving as the winding stator-side concave portion is located at a position outside the position projected along the rotating shaft 28a. A winding stator side recess 42S is formed.

  More specifically, a plurality of non-winding stator side recesses 42S extending along the radial direction of the circle centering on the rotation shaft 28a are formed on the surface of the second back yoke magnetic core 42 on the rotor 20 side. Yes. Each non-winding stator side recess 42S has approximately the same width as the groove 38S, and is provided in the same number (here, 12) as the groove 38S, and is further provided at approximately the same interval as the groove 38S (here In this case, the rotation shafts 28a are arranged at intervals of 30 degrees). Thereby, the same magnetic circuit can be formed on both sides of the rotor 20.

  Further, a specific mode in which each non-winding stator side recess 42S is disposed at a position deviated from the position where the groove 38S is projected along the rotation axis 28a is as follows. That is, the extending direction of each non-winding stator side recess 42S is deviated by a predetermined angle θ with respect to the extending direction of each groove 38S around the rotation shaft 28a.

  A preferable value of the deviation angle θ is (180 ÷ Nc) ° (where Nc is the least common multiple of the number of stator cores 34 of the winding stator 30 and the number of magnetic poles appearing on one side of the rotor 20). is there. The reason why such a deviation angle θ is preferable is as follows. That is, in the rotating electrical machine 10 according to the present embodiment, when the rotor 20 rotates once, the number of the stator magnetic cores 34 (here, 12) of the winding stator 30 appears on one side of the rotor 20. The basic waveform of the cogging torque appears by the least common multiple Nc of the number of magnetic poles (here, 8). Therefore, by setting the deviation angle θ to ((360 / Nc) / 2) °, that is, (180 ÷ Nc) ° as described above, the basic waveform of the cogging torque by the groove 38S on the winding stator 30 side, The basic waveform of the cogging torque by the non-winding stator-side recess 42S on the non-winding stator-side recess 42S side can be made in an opposite phase, and the cogging torque when viewed as a whole can be effectively suppressed. it can. Here, since Nc is 24 which is the least common multiple of 8 and 12, by setting the shift angle θ to (180 ÷ Nc) = 7.5 °, the basic waveforms of the respective cogging torques are reversed in phase. be able to.

  The axial gap type rotating electrical machine 10 is driven by, for example, a three-phase inverter. In general, a three-phase rotating electric machine driven by a three-phase inverter generates torque pulsation that is twice the number of phases per electrical angle cycle, that is, 3 × 2 = 6. That is, in one rotation, 24 torque pulsations obtained by multiplying the number of pole pairs by 6 are obtained. Therefore, by setting the deviation angle θ to (360/24) /2=7.5°, the torque waveform can be reversed and torque pulsation can be reduced.

  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 thrust 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, even if the number of stators is two, an increase in the number of coils can be suppressed. This makes it possible to shorten the process, simplify the connection, reduce the total amount of insulation between the coil and the core, and the like.

  In addition, a groove 38S is formed on the winding stator 30 side, and a non-winding stator side recess 42S is formed on the non-winding stator 40. The magnetic circuit can be made as identical as possible on the line stator 40 side. Moreover, the non-winding stator side recess 42S is a portion on the rotor 20 side, and is formed at a position deviating from the position where the groove 38S as the winding stator side recess is projected along the rotation axis 28a. Therefore, the cogging torque generation timing can be shifted between the winding stator 30 side and the non-winding stator 40 side to suppress the cogging torque as much as possible. That is, the cogging torque can be suppressed as much as possible while making the magnetic circuit the same as much as possible on the winding stator 30 side and the non-winding stator 40 side.

  Moreover, since the grooves 38S and the non-winding stator side recesses 42S are provided with substantially the same width, the same spacing, and the same number, the magnetic circuit is provided between the winding stator 30 side and the non-winding stator 40 side. Can be more the same. Further, the extending direction of each non-winding stator side recess 42S is deviated by a predetermined angle θ with respect to the extending direction of each groove 38S around the rotation shaft 28a, and the deviation angle θ is (180 ÷ Nc). Therefore, the basic waveform of the cogging torque by the groove 38S on the winding stator 30 side and the basic waveform of the cogging torque by the non-winding stator side recess 42S on the non-winding stator side recess 42S are opposite in phase. Can be. Thereby, cogging torque can be more effectively suppressed. It should be noted that the depth of the non-winding stator side recess 42S is sufficiently shallower than the groove 38S to a depth that does not interfere with the magnetic flux of the second back yoke magnetic core.

  The basic configuration of this axial gap type rotating electrical machine is as described above. In the following, on the assumption of the above configuration, a modified example, a preferable specific configuration, and the like will be described.

  In the above embodiment, the example in which the wide magnetic core 38 is provided has been described, but the wide magnetic core 38 may be omitted. In this case, each non-winding stator side recess 42S may be formed at a position deviating from the position where the grooves between the stator magnetic cores 34 are projected along the rotation axis 28a. The non-winding stator side recesses 42S may be provided with substantially the same width, substantially the same interval, and the same number as the grooves between the stator magnetic cores 34. Furthermore, the extending direction of each non-winding stator-side recess 42S may be shifted by the above angle θ with respect to the extending direction of the grooves between the respective stator magnetic cores 34.

  That is, a portion of the winding stator 30 on the rotor 20 side, such as the groove portion 38S between the wide magnetic cores 38 and a groove between the stator magnetic cores 34 when the wide magnetic core 38 is omitted, and each stator magnetic core. The position, shape, size, number, and the like of the non-winding stator side recesses 42S may be set with reference to the winding stator side recesses recessed with respect to the rotor 20 between 34.

  FIG. 5 is a diagram showing an example in which an intervening magnetic core is provided in the rotor.

  That is, the rotor 120 has a plurality (four in this case) of permanent magnets 122 arranged at intervals around the rotation axis 28a. A rotor magnetic core 124 is provided on the surface of each permanent magnet 122 on the winding stator 30 side. The permanent magnet 122 and the rotor magnetic core 124 have the same configuration as the permanent magnet 22 and the rotor magnetic core 24 except that the dimensions along the direction around the rotation shaft 28a are different. Further, the rotor 120 has intervening magnetic cores 128 that are magnetically independent of the permanent magnets 122 between the permanent magnets 122. The intervening magnetic core 128 faces both the winding stator 30 and the non-winding stator 40. That is, the permanent magnets 122 and the intervening magnetic cores 128 are annularly and alternately arranged around the rotation shaft 28a. Each permanent magnet 122 and the intervening magnetic core 128 are held in a magnetically independent state by a holder 126 formed of a non-magnetic material. As the intervening magnetic core 128, for example, an isotropic soft magnetic material such as a dust core is preferably used. In FIG. 5, the holder 126 is partially cut away for easy understanding.

  By providing the intervening magnetic core 128, 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 122, 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 gap length on both sides of the rotor 20 in the direction of the rotation 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 stator magnetic 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 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.

  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. 6 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). In addition, the 1st back yoke magnetic core 32 is fixed to the inner side of the airtight container 82 by welding etc. in an outer peripheral part. 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 from the upper end surface of the compression mechanism portion via a pin or the like.

  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 stator magnetic 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 hole 32h is also used as a refrigerant or refrigeration oil passage. Of course, it is possible to arbitrarily provide holes for allowing the refrigerant and the refrigerator oil to pass through the inner peripheral portion and the outer peripheral portion (portions not facing the rotor 20) of the first back yoke magnetic core 32 and the second back yoke magnetic core 42.

  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 supported 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 part 37 is provided inside the stator magnetic core 34, the cross line 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. 7 is a view showing a modification of the non-winding stator. The non-winding stator 240 according to this modification (corresponding to the non-winding stator 40) includes a second back yoke magnetic core 242 (the second back yoke) having a laminated steel plate portion 242a and a dust core ring portion 242b. Corresponding to the yoke magnetic core 42).

  The laminated steel plate portion 242a 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 242a is formed in a substantially disc shape having the same outer peripheral shape as that of the second back yoke magnetic core 42, and an annular recess 242ah is formed in an annular portion of the rotor 20 facing each permanent magnet 22. Has been.

  The dust core ring portion 242b is formed of a dust core and is formed in a ring shape that can be fitted into the annular recess 242ah. The dust core ring portion 242b is fitted and fixed to the annular recess 242ah by shrink fitting, welding, or the like.

  In this modified example, the laminated steel plate portion 242a can obtain the strength required to fix and hold the non-winding stator 240 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 242b.

  FIG. 8 is a cross-sectional view showing a modification of the compressor. Here, the inner diameter b1 of the first back yoke magnetic core 332 (corresponding to the first back yoke magnetic core 32) hole 332h of the winding stator 330 (corresponding to the winding stator 30) is defined as the non-winding stator 340 ( It is made smaller than the inner diameter b2 of the second back yoke magnetic core 342 (corresponding to the second back yoke magnetic core 42) of the non-winding stator 40). Further, the thickness dimension c1 of the first back yoke magnetic core 332 of the winding stator 330 is set smaller than the thickness dimension c2 of the second back yoke magnetic core 342 of the non-winding stator 340.

  That is, since the non-winding stator 340 has no coil, there are few restrictions on the shape, and thus the inner diameter of the shaft insertion hole 342h can be increased as described above. For example, it is possible to further reduce the inclination of the rotor 20 by providing a clearance for preventing contact with the rotating shaft portion 28, providing a refrigerant passage, or extending the bearing to the shaft insertion hole 742h. . When the inner diameter of the shaft insertion hole 342h is increased in this way, the magnetic path cross-sectional area at the second back yoke magnetic core 342 decreases. Therefore, the thickness of the second back yoke magnetic core 342 may be made relatively large, that is, larger than the thickness of the first back yoke magnetic core 332. Thus, the magnetic path cross-sectional areas of both the back yoke magnetic cores 332 and 342 can be made the same without making the first back yoke magnetic core 332 thicker than necessary and increasing the material used. It should be noted that increasing the inner diameter of the shaft insertion hole 342h of the non-winding stator 340 requires the insertion of the thick rotating shaft 28 necessary to connect the load (compression mechanism) and the rotor. Will inevitably be required. Further, the second back yoke magnetic core 342 of the non-winding stator 340 may be an electromagnetic 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 axial gap type rotary electric machine which concerns on 1st Embodiment. It is a perspective view which shows a rotary electric machine same as the above. It is a figure which shows the positional relationship of the winding stator side recessed part and non-winding stator side recessed part in 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 figure which shows the example which provided the interposition magnetic core in the rotor. It is sectional drawing which shows the compressor which concerns on 2nd Embodiment. 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, 120 Rotor 22, 122 Permanent magnet 24, 124 Rotor magnetic core 28a Rotating shaft 30, 330 Winding stator 32, 332 First back yoke magnetic core 34 Stator magnetic core 36 Coil 37 Wiring part 37a External wiring 38 Wide magnetic core 38a Connecting portion 38S Groove 40, 240, 340 Non-winding stator 42, 242, 342 Second back yoke magnetic core 42S Non-winding stator side recess 80 Compressor 90 Compression mechanism 128 Intervening core

Claims (9)

A rotor (20, 120) that is rotatably arranged around the rotation axis (28a) and presents a plurality of magnetic poles around the rotation axis on both surfaces in the rotation axis direction;
A gap is disposed on one side of the rotor in the direction of the rotation axis with a gap therebetween, and the first back yoke magnetic core (32, 132) having a substantially disk shape and the rotation on the rotor side of the first back yoke magnetic core. A winding stator having a plurality of stator cores (34) disposed along an axis and a coil (36) for generating a rotating magnetic field on a surface of each stator core facing the rotor. (30, 330),
A non-winding stator (40, having only a substantially disc-shaped second back yoke magnetic core (42, 242, 342) disposed on the other side of the rotor in the direction of the rotation axis with a gap therebetween. 240, 340),
With
A winding stator side recess (38S) that is recessed with respect to the rotor is formed between the stator magnetic cores on the rotor side of the winding stator,
In the radial direction of the non-winding stator, in the rotor-side portion of the non-winding stator and at a position outside the position where the winding stator-side recess is projected along the rotation axis. An axial gap type rotating electrical machine in which a non-winding stator side recess (42S) extending along the axis is formed. The axial gap type rotating electrical machine according to claim 1,
The winding stator side recesses are axial grooves which are grooves between the stator magnetic cores (34) or grooves (38S) between the wide magnetic cores (38) attached to the tip of the stator magnetic cores. Gap type rotating electrical machine. An axial gap type rotating electrical machine according to claim 1 or 2,
Each of the non-winding stator side recesses (42S) and each of the winding stator side recesses (38S) is provided with approximately the same width, approximately the same interval, and the same number, and an axial gap type rotating electrical machine. It is an axial gap type rotary electric machine in any one of Claims 1-3,
The angle at which the extending direction of each non-winding stator side recess (42S) deviates from the extending direction of each winding stator side recess (38S) about the rotation axis is (180 ÷ Nc) °. (Where Nc is the least common multiple of the number of the respective stator magnetic cores of the winding stator and the number of magnetic poles appearing on one side of the rotor). It is an axial gap type rotary electric machine in any one of Claims 1-4,
The rotor (120) includes a plurality of permanent magnets (122) disposed at intervals around the rotation axis,
An axial gap type rotating electrical machine in which an intervening magnetic core (128) magnetically independent from each permanent magnet is interposed between the permanent magnets.   The compressor (80) provided with the axial gap type rotary electric machine in any one of Claims 1-5. The compressor according to claim 6, wherein
A compression mechanism (90) that receives a rotational drive of the axial gap type rotating electrical machine and performs a compression operation;
The non-winding stator (40, 340) is a compressor provided on the compression mechanism section side with respect to the rotor (20). The compressor according to claim 7, wherein
The winding stator side end of the rotating shaft portion (28) of the rotor is provided at a position not penetrating the winding stator, and the wiring portion (37) of each coil is A compressor provided on the rotating shaft side of the coil. A compressor according to claim 7 or claim 8, wherein
The inner diameter (B1) of the first back yoke magnetic core (332) of the winding stator (330) is smaller than the inner diameter (b2) of the second back yoke magnetic core (342) of the non-winding stator (340). ,
The thickness (c1) of the first back yoke magnetic core of the winding stator in the rotation axis direction is smaller than the thickness (c2) of the second back yoke magnetic core of the non-winding stator in the rotation axis direction. .

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