JP2014192942A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary machine having a Halbach array field magnet, capable of reducing the cost of manufacture.SOLUTION: A rotary machine 1 configuring a motor and a power generator, comprises a dual Halbach array field magnet configured by respectively arranging permanent magnets 41 and 51 whose cross section vertical to a rotation shaft is rectangular, in a ring shape. The permanent magnets 41 and 51 with the rectangular cross section are arranged in a ring shape at equal angle intervals, respectively. Since wedge-shaped gaps are provided between the adjacent magnets, it is preferred that members for filling those gaps are interposed. Such members are configured by a non-magnetic non-conductive material. By using the permanent magnets whose cross section vertical to the rotation shaft is rectangular, procurement cost of permanent magnets can be suppressed, and rotary machine manufacture can be achieved at low cost. In addition, the usage of such permanent magnets brings about reduction in magnet usage amount, and thus, it can contribute to resource saving. Further, by interposing the members between the adjacent permanent magnets, positioning of the permanent magnets is facilitated, and thereby, the intensity of field magnet and productivity can be improved.

Description

  The present invention relates to a rotating machine such as a coreless motor and a coreless generator, and more specifically to a rotating machine including a Halbach array field formed by arranging permanent magnets in a ring shape.

  In conventional motors and generators, permanent magnets are arranged so that N poles and S poles are alternately arranged, but with such an arrangement structure, a magnetic field is generated on both the front side and the back side of the magnet arrangement. The magnetic field cannot be used effectively. Therefore, a permanent magnet arrangement structure called “Halbach arrangement” has been proposed as means for increasing the magnetic field of a motor or generator.

  In the Halbach arrangement, the magnetic poles of the permanent magnets are arranged while being rotated by 90 °, so that the magnetic field on one side of the magnet arrangement is weakened, and on the other side of the magnet arrangement, the magnetic field is increased accordingly and becomes permanent. A strong magnetic field can be generated on one side of the magnet array. Therefore, as shown in FIG. 10, there has been proposed a permanent magnet rotating machine in which an armature coil is arranged between two rows of permanent magnet arrays (dual Halbach array) each arranged in a Halbach array (Patent Document 1).

JP 2009-201343 A

  In a rotating machine using a permanent magnet dual Halbach array field, that is, a coreless motor or a coreless generator, a permanent magnet having a trapezoidal cross section as shown in FIG. 10 is generally used to configure the field in a ring shape. Has been. However, the trapezoidal cross section permanent magnet is more expensive than the rectangular cross section permanent magnet, and the procurement cost of the permanent magnet is high. Therefore, there is a problem in that a large amount of cost is required for manufacturing the rotating machine.

  Therefore, in view of the above-described problems, an object of the present invention is to provide a rotating machine having a Halbach array field that can be easily manufactured while reducing the manufacturing cost.

  Such an object is achieved by a rotating machine including a Halbach array field formed by arranging permanent magnets having a rectangular cross section perpendicular to the rotation axis in a ring shape. When permanent magnets having a rectangular cross section are arranged in a ring shape, a wedge-shaped gap is inevitably generated between adjacent magnets. Therefore, it is preferable to interpose a member filling the gap. The constituent material of such an interposition member is not particularly limited, but is preferably made of a nonmagnetic material, more preferably a nonmagnetic / nonconductive material.

  In the rotating machine of the present invention, a permanent magnet having a rectangular cross section perpendicular to the rotation axis is used as a constituent member of the Halbach array field. Permanent magnets having a rectangular cross section are generally mass-produced and are provided at a low price. Therefore, the procurement cost of permanent magnets can be significantly reduced as compared with the case where a permanent magnet having a trapezoidal cross section is used. Therefore, according to the present invention, it is possible to manufacture a rotating machine at a lower cost compared to a conventional product using a permanent magnet having a trapezoidal cross section. In addition, since permanent magnets can be procured at a low cost, a small quantity of various types of rotating machines can be provided at a low price. In addition, by using a permanent magnet having a rectangular cross section, the cross sectional area of the permanent magnet is reduced, and the amount of magnet usage is reduced accordingly, thereby contributing to resource saving.

  Further, in the present invention, since permanent magnets having a rectangular cross section perpendicular to the rotation axis are arranged in a ring shape to form a Halbach field, a wedge-shaped gap is generated between the permanent magnets. Is configured to interpose a clogging member. In this way, by interposing the interstitial member between the adjacent permanent magnets, the positioning of the permanent magnets is facilitated, and the field productivity is improved. Further, by filling the gap between the permanent magnets with the filling member, it is possible to prevent the permanent magnets from being blurred, and the field strength is improved. Therefore, even if a permanent magnet having a rectangular cross section is used instead of a permanent magnet having a trapezoidal cross section, the strength and manufacturability of the rotating machine are not impaired.

  In addition, when using a permanent magnet for the field of an electric motor or a generator, a permanent magnet is normally used in the form which contacted the ferromagnetic material. For this reason, when a ring-shaped field is constituted by a permanent magnet having a rectangular cross section, it tends to be recalled that a ferromagnetic material is interposed in the gap between the magnets to lower the magnetic resistance of the main magnetic flux. Then, the magnetic flux in the gap is not reduced when a material having a relative permeability close to 1 is interposed.

It is a schematic sectional drawing of the radial direction which shows the rotating machine of this invention (sectional drawing of a direction perpendicular | vertical to the rotating shaft of a rotating machine). It is an axial sectional view showing a single layer field rotating machine, and is a schematic sectional view taken along line VV in FIG. It is an axial sectional view showing a multilayer field rotating machine. 3 is a graph showing measurement results of Example 1. 3 is a graph showing measurement results of Example 1. 6 is a graph showing measurement results of Example 2. 6 is a graph showing measurement results of Example 2. It is a graph which shows the measurement result of a comparative example. It is a graph which shows the measurement result of a comparative example. It is radial direction sectional drawing (sectional drawing of a direction perpendicular | vertical to the rotating shaft of a rotary machine) which shows the conventional rotary machine.

  The present invention relates to a rotating machine (permanent magnet rotating electric machine) such as a coreless motor or a coreless generator using a Halbach array of permanent magnets. Hereinafter, based on FIG.1 and FIG.2, embodiment of the rotary machine which concerns on this invention is described.

  The rotating machine 1 includes a rotor 3 and a stator 7. A generator can be configured by attaching a shaft to the rotor 3 and rotating the shaft. The rotor 3 includes permanent magnet arrays 4 and 5 constituting a dual Halbach array field. The stator 7 includes a coil array 8.

  The permanent magnet arrays 4 and 5 are each configured in a ring shape, and the coil array 8 is also configured in a ring shape. The permanent magnet array 4 is provided inside the permanent magnet array 5. The permanent magnet arrays 4 and 5 and the coil array 8 are arranged concentrically.

  As shown in FIG. 1, each of the permanent magnet arrays 4 and 5 constituting the dual Halbach array field is a “Halbach array” in which the magnetic poles of the permanent magnets are rotated approximately 90 ° in the circumferential direction and arranged in a ring shape. It has become. The number of magnets in the permanent magnet array 4 and the permanent magnet array 5 is the same. The permanent magnets 41, 41... Constituting the permanent magnet array 4 are both rectangular in cross section in a cross section parallel to the magnetization direction (a cross section perpendicular to the rotation axis of the rotating machine). Similarly, the permanent magnets 51, 51... Constituting the permanent magnet array 5 have a rectangular cross-sectional shape.

  Since the same-shaped permanent magnets 41 having such a rectangular cross section are arranged in a ring shape at equal angular intervals, a wedge-shaped gap is provided between adjacent permanent magnets 41 and 41. In these wedge-shaped gaps, wedge-shaped filling members 43 are interposed to fill the gaps. Similarly, there is a wedge-shaped gap between the adjacent permanent magnets 51, 51, and a wedge-shaped filling member 53 is interposed in the wedge-shaped gap to fill the gap.

  In the present invention, it is possible to adopt a mode in which air is interposed without disposing the clogging member in the gap between the rectangular cross-section permanent magnets, but it is preferable to interpose the clogging member as described above. The material of the filling members 43 and 53 is not particularly limited, and can be made of, for example, a nonmagnetic material such as aluminum, and is preferably made of a nonmagnetic / nonconductive material such as resin.

  The method of interposing the clogging member in the gap between the permanent magnets is not particularly limited, and any method can be adopted as long as some member is interposed in the gap between the permanent magnets in the completed state of the rotating machine. For example, after arranging the permanent magnets in a ring shape, some material (a member separate from the magnet) may be inserted or filled in the gap between the adjacent permanent magnets. Or you may arrange | position so that a permanent magnet may be inserted between the filling members arrange | positioned and fixed beforehand at equal angle intervals.

  The magnetic pole direction of the permanent magnets magnetized in the radial direction of the permanent magnets 41 of the permanent magnet array 4 and the magnetic pole direction of the permanent magnets magnetized in the radial direction of the permanent magnets 51 of the permanent magnet array 5 are the same radius. Those arranged above are the same. In addition, the magnetic pole direction of the permanent magnet magnetized in the circumferential direction of the permanent magnet 41 of the permanent magnet array 4 and the magnetic pole direction of the permanent magnet magnetized in the circumferential direction of the permanent magnet 51 of the permanent magnet array 5 are the same radius. The ones placed above are the opposite.

  In the inner permanent magnet array 4, the magnetic poles of the permanent magnets 41 are arranged in a ring shape while being rotated by about 90 ° in the circumferential direction. A strong magnetic field can be generated and a strong magnetic field can be generated outside the permanent magnet array 4. Further, in the outer permanent magnet arrangement 5, the magnetic poles of the permanent magnets 51 are arranged in a ring shape while being rotated by about 90 ° in the circumferential direction. Accordingly, the magnetic field becomes stronger, and a strong magnetic field can be generated inside the permanent magnet array 5.

  Since the permanent magnet arrays 4 and 5 are configured in this way, the magnetic field in the space between the magnet arrays 4 and 5 becomes strong, while on the other hand, inside the permanent magnet array 4 and outside the permanent magnet array 5. The magnetic field hardly leaks. Since the coil array 8 is concentrically arranged between the permanent magnet arrays 4 and 5, a high voltage can be generated. Thus, since the magnetic field in the region where the coil array 8 is arranged becomes strong, a high voltage can be generated without using an iron core for the coils constituting the coil array. And since an iron core is not used, cogging can be eliminated.

  The above-described embodiment is an example, and the present invention described in the claims includes various modifications. For example, the scope of application of the present invention is not limited to a single-layer field as shown in FIG. 2, and the present invention can also be applied to a rotating machine having a multilayer field as shown in FIG. The present invention can also be applied to a multi-stage field rotating machine including a plurality of such single-layer fields or multilayer fields.

Example 1
Using a permanent magnet having a rectangular cross section as shown in FIG. 1, the ring-shaped dual Halbach field was configured in three layers as shown in FIG. Nothing was inserted in the wedge-shaped gap between the permanent magnets, and air was interposed. FIG. 4 and FIG. 5 show the magnetic flux density distribution in the gap center circumferential direction of the first layer and the third layer.

(Example 2)
Using a permanent magnet having a rectangular cross section as shown in FIG. 1, the ring-shaped dual Halbach field was configured in three layers as shown in FIG. The wedge-shaped iron between the permanent magnets was inserted with wedge-shaped iron filling the gap. FIG. 6 and FIG. 7 show the magnetic flux density distribution in the gap center circumferential direction of the first and third layers.

(Comparative example)
Using a permanent magnet having a trapezoidal cross section as shown in FIG. 10, the ring-shaped dual Halbach field was configured in three layers as shown in FIG. FIG. 8 and FIG. 9 show the magnetic flux density distribution in the circumferential direction at the center of the gap of the first layer and the third layer.

(Evaluation)
As is apparent from the results shown in FIGS. 4 to 9, when a dual Halbach array field is configured using permanent magnets having a rectangular cross section perpendicular to the rotation axis, the angle expected per magnet is about 5 °. If it exists, even if a nonmagnetic and nonconductive member is inserted in the space between the magnets, it can be seen that the magnetic flux density at the center of the field gap is only reduced by about 3%. Also, a sine wave with a clean magnetic flux density distribution is obtained, and no difference due to the shape change of the permanent magnet cross section is recognized.

  On the other hand, if iron is inserted and interposed between the rectangular gaps between the permanent magnets having a rectangular cross section, the magnetic resistance is reduced in terms of the magnetic circuit, so an increase in magnetic flux density is expected. It can be seen that the magnetic flux density is reduced because the iron is concentrated.

  As described above, when configuring a dual Halbach field with a permanent magnet having a rectangular cross section perpendicular to the rotation axis, a nonmagnetic / nonconductive member should be installed and fixed in advance in a position corresponding to the gap. Thus, the positioning of the permanent magnet at the time of field assembly can be easily performed. In addition, since a non-magnetic / non-conductive member is used, it is possible to avoid a decrease in the magnetic flux density in the field gap, and there is no generation of eddy currents due to magnetic flux fluctuations produced by the armature coil. Therefore, a reduction in energy efficiency of the apparatus can be avoided.

1 Rotating machine (permanent magnet rotating electrical machine)
3 Rotor 4 Permanent magnet arrangement (inner magnet arrangement)
5 Permanent magnet arrangement (outside magnet arrangement)
7 Stator 8 Coil arrangement 41 Permanent magnet 43 Spacing member (intervening member)
51 Permanent magnet 53 Spacing member (intervening member)

Claims (3)

  A rotating machine provided with a Halbach array field in which permanent magnets having a rectangular cross section perpendicular to a rotation axis are arranged in a ring shape.   The rotating machine according to claim 1, further comprising a member provided so as to be interposed in a gap between adjacent permanent magnets.   The rotating machine according to claim 2, wherein the member interposed in a gap between adjacent permanent magnets is made of a nonmagnetic material.