JP2012065379A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary machine in which eddy current that is a factor of a magnetic force drop of a permanent magnet is reduced as much as possible, a temperature rise due to the eddy current is suppressed, demagnetization due to the temperature rise is suitably suppressed, a magnetic field in an opposite direction due to the eddy current is suppressed, a permeance coefficient is enlarged to suppress an anti-magnetic field, and size reduction of a rotor is realized while a thick shaft is applied.SOLUTION: A parallel anisotropic magnet in which a plurality of unit magnets 6 are arranged in a circumferential direction of the shaft 4, and magnetization directions of all the unit magnets 6 are set in a direction orthogonal to an arranging direction 6A is applied as a permanent magnet 5. In each unit magnet 6, a magnet width 61W of a center-side unit magnet 61 in which a face opposite to a face which is arranged in a center region 3C of the rotor 3 in the arranging direction 6A and constitutes a magnetic pole is brought into contact with the shaft 4 is set smaller than a maximum magnet width 62W of a side unit magnet 62 arranged in a side edge region 3S of the rotor 3 in the arranging direction 6A.

Description

  The present invention relates to a rotating machine such as a motor or a generator in which a rotor is configured to be rotatable with respect to a stator.

  Conventionally, as a rotating machine used as a motor or generator, a rotor (rotor) with a permanent magnet around the shaft axis can be freely rotated with respect to a stator (stator) in which coils are wound around stator teeth. The one that is pivotally supported by is used. In such a rotating machine, when an exciting current is supplied to the coil, the rotor can be rotated around the shaft axis by a magnetic circuit formed between the opposing stator teeth and the permanent magnet.

  By the way, when an exciting current is supplied to the coil, an eddy current is generated in the permanent magnet itself. As a cause of the generation of the eddy current, there are a fundamental frequency component corresponding to the number of rotations of the rotor and a high frequency component generated by inverter control (for example, PWM and PAM) and a slot shape of the rotor. It is known that a large amount of eddy current is generated on the outer surface which is a surface constituting the magnetic pole of the permanent magnet, that is, the surface facing the stator teeth, by this high frequency component. It is known that the magnetic force decreases (demagnetizes) when the permanent magnet generates heat due to this eddy current and becomes high temperature. In addition, it is known that an eddy current generates a magnetic field in a direction opposite to a magnetic field that is originally desired, which also causes a decrease in magnetic force as a whole.

  Therefore, in the conventional rotor, a permanent magnet is constituted by a magnet (hereinafter referred to as “unit magnet”) divided into a plurality of parts so as to surround the surface of the shaft. If a permanent magnet is constituted by a plurality of unit magnets divided in this way, an eddy current is generated on the outer surface of each unit magnet, but eddy current is compared with a case where a permanent magnet is constituted by one magnet without division. By subdividing the current path (current path), the amount of eddy current generated in the entire rotor can be reduced, and temperature rise due to eddy current is suppressed, and magnetic field in the opposite direction due to eddy current is also suppressed. be able to.

  In addition, a “demagnetizing field” that generates a magnetic field in the direction opposite to the magnetization direction of the magnet appears inside the permanent magnet. The demagnetizing field is also referred to as “demagnetizing field”. Here, the magnitude of the demagnetizing field is proportional to the magnitude of the magnetization, and the demagnetizing factor, which is a proportional constant thereof, is a factor determined only by the shape of the magnet as with the permeance factor. The larger the permeance factor, the more the demagnetizing factor It is known that the smaller the permeance coefficient is, the larger the demagnetizing factor is, and the larger the demagnetizing factor is, the smaller the magnetic force of the magnet becomes (it becomes easier to demagnetize). The permeance coefficient becomes smaller as the length (magnet thickness) of the magnetizing direction (also referred to as “orientation direction” or “magnetization direction”) of the magnet becomes smaller than the area of the outer surface that constitutes the magnetic pole. Decreases and the demagnetizing factor increases.

  As an aspect in which the permanent magnet is constituted by a magnet divided into a plurality of parts so as to surround the surface of the shaft (hereinafter referred to as “unit magnet”), radial orientation (orientation in which a magnetic field toward the stator diffuses toward the stator) (For example, patent document 1) which has the structure which provided the unit magnet magnetized by 1 at the circumferential direction of the shaft at equal intervals.

  The unit magnets magnetized in the radial orientation have a general fan shape that gradually spreads from the surface that can contact the shaft (inward surface) toward the outer surface that constitutes the magnetic pole, and the magnetization direction of each unit magnet Are equal in length (magnet thickness), and any unit magnet has an equivalent permeance coefficient.

JP 2006-217771 A

  By the way, when applying a thick shaft to withstand high-speed rotation and setting the outer diameter of the rotor small to reduce the size of the entire rotor, the length of each unit magnet in the magnetization direction The (magnet thickness) must be set short (thin). However, if the unit magnets magnetized in the radial orientation are provided on the outer surface of the shaft, the magnet thickness with respect to the outer surface constituting the magnetic pole is set by setting the magnet thickness in the magnetization direction of each unit magnet thin. Therefore, the permeance coefficient is also reduced. As a result, a strong demagnetizing field appears to reduce the magnetic force, which can lead to a decrease in operating efficiency and unexpected heat generation.

  Therefore, in order to suppress a decrease in the magnetic force of each unit magnet, the unit magnets are magnetized in parallel orientation (orientation in which the magnetic fields toward the stator are parallel to each other) in order to increase the permeance coefficient and reduce the demagnetizing field. It is also conceivable that the permanent magnets are arranged by arranging them on the outer surface of the shaft at equal intervals without gaps.

  However, if you want to set a small outer diameter of the rotor itself while applying a thick shaft so that it can withstand high-speed rotation, among the unit magnets arranged at equal pitch along the circumferential direction on the outer surface of the shaft, The length (magnet thickness) of the magnetizing direction of the unit magnets arranged in the central region of the rotor in the arrangement direction of the unit magnets is arranged in both side edge regions of the rotor in the arrangement direction of the unit magnets. Since the thickness is smaller (thinner) than the magnet thickness of the permanent magnet, the permeance coefficient is inevitably small, and a problem that a demagnetizing field tends to appear strongly may occur. Therefore, it is difficult to reduce the diameter and size of the rotor.

  The present invention has been made paying attention to such a problem, and the main purpose is to minimize the eddy current that causes a decrease in the magnetic force of the permanent magnet as much as possible, to suppress the temperature rise due to the eddy current, The demagnetization accompanying the rise can be suitably suppressed, the magnetic field in the opposite direction due to the eddy current can also be suppressed, and further, the demagnetizing field is suppressed by increasing the permeance coefficient determined by the shape of the magnet, An object of the present invention is to provide a rotating machine that satisfies the design requirements for realizing high-speed rotation, that is, a rotating machine that can reduce the rotor diameter while applying a thick shaft.

  That is, the present invention includes a rotor having a permanent magnet that is attached to the shaft and the outer surface of the shaft to form a magnetic pole, and a non-rotatable stator that accommodates a rotor that is rotatable about the shaft axis in an internal space. The present invention relates to a rotating machine provided. Here, “accommodating the rotor in the internal space” means that at least all or most of the region of the rotor where the permanent magnet is attached is accommodated in the internal space, and the region of the shaft where the permanent magnet is not attached All or most of these are concepts that include an aspect in which they are arranged outside the internal space of the stator or an aspect in which the entire rotor is accommodated.

  The rotating machine of the present invention is a parallel anisotropy in which a plurality of unit magnets are arranged in the circumferential direction of the shaft as a permanent magnet, and the magnetization direction of all the unit magnets is set in a direction orthogonal to the arrangement direction of the unit magnets. Applying the magnet, among the unit magnets, the magnet width of the unit magnets arranged in the central region of the rotor in the arrangement direction, and the maximum magnet width of the unit magnets arranged in the side end region of the rotor in the arrangement direction It is characterized by being set smaller.

  Here, the “magnet width” is the length in the direction orthogonal to the magnetization direction, in other words, the length in the arrangement direction of the unit magnets. Further, in the unit magnets arranged in the central region of the rotor in the arrangement direction, the surface opposite to the surface (outer surface) constituting the magnetic pole (hereinafter referred to as “inward surface”) can contact the shaft. It is also a unit magnet.

  The present inventors configure a permanent magnet by a plurality of unit magnets magnetized in parallel orientation, and are arranged in the central region of the rotor among the unit magnets so that the inward surface comes into contact with the shaft (surface contact). A unit magnet (hereinafter referred to as “center-side unit magnet”) is a unit magnet (hereinafter referred to as “side-side unit magnet”) that is disposed in a side end region of the rotor and does not contact (surface contact) with the shaft. Compared with the fact that the length in the magnetization direction (hereinafter referred to as “magnet thickness”) is short (thin), the permeance coefficient is small and the demagnetizing field tends to appear strongly. The inventors have come up with a novel technical idea that the magnet width is set smaller than the maximum magnet width of the side unit magnet. In the claims, “the maximum magnet width of the unit magnets arranged in the side end region of the rotor in the arrangement direction” means the unit magnets (side side unit) arranged in the side end region of the rotor in the arrangement direction. Means the magnet width of the side-side end unit magnet having the longest length in the arrangement direction.

  And by setting the magnet width of the center side unit magnet relatively smaller than the maximum magnet width of the side side unit magnet, the area of the outer surface of each center side unit magnet is also reduced, and the magnet for the area of this outer surface The thickness ratio can be increased. As a result, the permeance coefficient of each center-side unit magnet increases, and the demagnetizing field that can be generated in each center-side unit magnet can be suppressed. Furthermore, since a large amount of eddy current is generated especially on the outer surface of the magnet, the amount of eddy current that can be generated is suppressed as much as possible by setting the area of the outer surface of each center unit magnet to be relatively small. Thus, it can be expected that the temperature increase due to the eddy current is suppressed and the magnetic field in the opposite direction due to the eddy current is also suppressed.

  Thus, the rotor according to the present invention constitutes a configuration in which the magnet width of the center-side unit magnet is made smaller than the maximum magnet width of the side-side unit magnet, in other words, a permanent magnet that is a parallel anisotropic magnet. Among the unit magnets, the center side unit magnet arranged in the central region of the rotor in the direction orthogonal to the magnetization direction is larger than the one having the largest magnet width among the side side unit magnets arranged in the side end region of the rotor. The configuration of fine division can eliminate the disadvantage of the center unit magnet based on the shape of the relatively thin magnet, that is, the weakness against the demagnetizing field.

  In particular, in order to achieve high rotation, when setting the outer diameter of the rotor itself while applying a thick shaft, it is necessary to set the magnet thickness of the center unit magnet thinly, Even in this case, according to the present invention, the demagnetizing field can be suitably suppressed by reducing the magnet width of the center unit magnet to be smaller than the maximum magnet width of the side unit magnet. Without obtaining, it is possible to reduce the diameter and size of the rotor.

  In the rotating machine of the present invention, when a cylindrical shaft is used as the shaft, the unit magnets arranged in the region corresponding to the diameter range of the shaft are arranged in the central region of the rotor. A unit magnet that is a center-side unit magnet and is disposed in a region corresponding to the outside of the shaft diameter range is a side-side unit magnet that is disposed in a side end region of the rotor.

  In the rotating machine of the present invention, the magnet width of the center unit magnet can be set as appropriate. However, the eddy current generated on the outer surface of each center unit magnet can be effectively reduced to increase the temperature due to the eddy current. In order to reduce the demagnetizing field by increasing the permeance coefficient determined by the magnet shape, the magnet width of the center unit magnet is set to the magnet thickness (length in the magnetization direction) of the center unit magnet. It is preferable to set it to one half or less of the above.

  According to the present invention, the center-side unit magnet, which is composed of a plurality of unit magnets obtained by dividing a permanent magnet that is a parallel anisotropic magnet and is arranged in the central region of the rotor in a direction orthogonal to the magnetization direction, By setting the magnet width to be smaller than the maximum magnet width of the side-side unit magnets arranged in the side end region of the rotor and increasing the number of magnet divisions in the central region of the rotor, temperature rise due to eddy current is suppressed. In addition, the magnetic field in the opposite direction due to eddy currents can be suppressed, and further, the demagnetizing field can be reduced by increasing the permeance coefficient determined by the shape of the magnet. And a rotating machine capable of rotating at high speed can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS The whole structure schematic diagram which shows a partially broken brushless high-speed rotating machine which concerns on one Embodiment of this invention. The whole block schematic diagram of the rotor of the brushless high-speed rotating machine concerning the embodiment. The A direction arrow directional view of FIG. FIG. 4 is a view in the direction of arrow B in FIG. 3. The graph which shows the relationship between a magnet division number and a magnet loss.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the rotating machine 1 according to the present embodiment includes a stator 2 (corresponding to a “stator” of the present invention) and a rotor 3 that can rotate with respect to the stator 2 (“rotor” of the present invention). For example, a brushless high-speed rotating machine that can be used as a motor or a generator. The rotating machine 1 of the present embodiment is a so-called inner rotor type brushless rotating machine in which a rotor 3 is disposed inside a stator 2.

  The stator 2 includes a substantially cylindrical stator base 21, a stator tooth 22 provided so as to protrude from the inner peripheral surface of the stator base 21 at equal intervals in the circumferential direction, and a stator coil 23 wound around the stator tooth 22. It is equipped with.

  In the present embodiment, the axis of the stator base 21 is made to coincide with the rotational axis 3J of the rotor 3, and a substantially disk shape in which both ends (open ends) of the stator base 21 are formed with shaft insertion holes 24a. The cover 24 is attached. A bearing support ring 25 is provided on the inward surface of the cover 24, and a bearing 26 that rotatably supports the shaft 4 of the rotor 3 is attached to the bearing support ring 25. A known ball bearing or the like can be used as the bearing 26.

  The stator teeth 22 have a protruding shape that protrudes from the inner peripheral surface of the stator base 21 toward the rotor 3 and extends along the axial direction. In the present embodiment, a predetermined number of such stator teeth 22 are provided at equal intervals in the circumferential direction on the inner peripheral surface of the stator base 21.

  The stator coil 23 is wound around the stator tooth 22 in a predetermined form (overlapping, wave winding, chain winding, concentrated winding, etc.), and a part of the stator coil 23 is formed at both end faces of the stator tooth 22. It protrudes in a loop shape and functions as a coil end.

  2 to 4 (FIG. 2 is an overall schematic view of the rotor 3, FIG. 3 is a view taken in the direction of arrow A in FIG. 2, and FIG. 4 is a view taken in the direction of arrow B in FIG. 3) As shown in FIG. 4, the shaft 4 and the permanent magnet 5 provided on the outer peripheral surface of the shaft 4 are provided.

  The shaft 4 has a substantially cylindrical shape, and its axis is the rotational axis 3J of the rotor 3. In the present embodiment, the vicinity of both ends of the shaft 4 is supported by the above-described bearing 26 (see FIG. 1).

  The permanent magnet 5 is a parallel anisotropic magnet composed of a plurality of unit magnets 6 magnetized in parallel orientation in which the orientation directions (magnetization directions) are parallel. In the present embodiment, as shown in FIG. 3, the magnetization direction of all the unit magnets 6 arranged in the circumferential direction of the shaft 4 is set to be a direction orthogonal to the arrangement direction 6 </ b> A of the permanent magnets 5. . That is, the magnetization directions of all the unit magnets 6 are set to be parallel to each other. In FIG. 3, the magnetization direction of each permanent magnet 5 is indicated by an arrow. As described above, the permanent magnet 5 of the present embodiment, in which all the unit magnets 6 are divided and arranged in the circumferential direction of the shaft 4 so that the magnetization directions thereof are parallel to each other, has a two-pole magnet field. Constitute. Further, the plurality of unit magnets 6 arranged along the circumferential direction of the shaft 4 have their respective shapes determined so as to form a substantially cylindrical shape whose axial center matches the axial center of the shaft 4 (FIG. 2). And FIG. 3). Further, the permanent magnet 5 of the present embodiment is provided with a plurality of sets 6G of unit magnets 6G (unit magnet group, see FIG. 2) having a substantially cylindrical shape at equal intervals along the axial direction of the shaft 4. Each unit magnet 6 can be fixed to the outer peripheral surface of the shaft 4 with an adhesive or the like. However, in this embodiment, the unit magnet 6 is attached to the shaft 4 using the magnetic force attracting the unit magnet 6 and the shaft 4 to each other. It is attached in a state of being arranged in the circumferential direction.

  Balance rings 7 are provided at both ends of the permanent magnet 5 in the axial direction of the shaft 4. Moreover, the scattering prevention member 8 which prevents each unit magnet 6 from separating | separating from the shaft 4 and scattering on the outer periphery of the permanent magnet 5 can also be provided. In the present embodiment, the scattering prevention member 8 is a cylindrical member that can accommodate all the unit magnets 6 arranged on the outer peripheral surface of the shaft 4 in the internal space. Further, a predetermined gap is secured between the stator 2 and the rotor 3, specifically, between the stator teeth 22 and the scattering prevention member 8.

  It is effective as a countermeasure against eddy current to configure the permanent magnet 5 with a plurality of unit magnets 6, that is, a configuration in which the permanent magnet 5 is divided into a plurality of parts. FIG. The general relationship with (eddy current loss) is shown. The reason why the eddy current can be reduced by dividing the permanent magnet 5 forming the magnetic pole is that the eddy current path (current path) is subdivided by the division. The horizontal and vertical axes in FIG. 5 are the number of magnet divisions and the magnet loss, respectively. In FIG. 5, the magnet loss when the number of divisions is 1 is 1, and the magnet loss according to the number of divisions is the ratio. Is shown.

  Then, as shown in FIGS. 3 and 4, the rotating machine 1 of the present embodiment has a unit magnet 6 arrangement direction 6 </ b> A when facing the rotor 3 among the unit magnets 6 arranged in the circumferential direction of the shaft 4. When the rotor 3 is directly opposed, the magnet width 61W of the center unit magnet 61 disposed in the central region 3C corresponding to the diameter range of the shaft 4 in the rotor 3 is the shaft 4 in the rotor 3 in the alignment direction 6A. Is set to be smaller (shorter) than the maximum magnet width 62W of the side unit magnet 62 disposed in the side end region 3S corresponding to the outside of the diameter range. In the present embodiment, the magnet width 61W of the center side unit magnet 61 is set to about one half or less of the magnet width 62W of the side unit magnet 62. In other words, the magnet width 62W of the side unit magnet 62 is set to about twice or more the magnet width 61W of the center unit magnet 61.

  Here, the center-side unit magnet 61 in the present embodiment has a surface (inward surface) on the opposite side to the surface constituting the magnetic pole disposed in the central region 3C of the rotor 3 in the arrangement direction 6A of the unit magnets 6. It is a unit magnet that can come into surface contact with the shaft 4. Further, the side unit magnet 62 is a unit magnet that is disposed in the side end region 3S of the rotor 3 in the arrangement direction 6A of the unit magnets 6 and cannot make surface contact with the shaft 4. The “magnet width” of the unit magnets 6 is the length in the direction orthogonal to the magnetization direction of the unit magnets 6, in other words, the length in the arrangement direction 6 </ b> A of the unit magnets 6.

  In the present embodiment, as a manner of dividing the permanent magnet 5, the central region 3C of the rotor 3 is divided into equal widths, and the side end region 3S of the rotor 3 is divided into equal widths. Therefore, in the rotating machine 1 of the present embodiment, the magnet widths 61W of the plurality of center-side unit magnets 61 are equal and the magnet widths 62W of the plurality of side-side unit magnets 62 are equal to each other. “Width” has the same meaning as “magnet width 62W of the side unit magnet 61”.

  In the present embodiment, the magnet width 61W of the center side unit magnet 61 is set to less than or equal to one half of the magnet thickness of the center side unit magnet 61, more specifically, about one third to one fourth. ing. Conversely, the magnet thickness of the center side unit magnet 61 is set to be not less than twice the magnet width 61W of the center side unit magnet 61, more specifically, about 3 to 4 times.

  The rotating machine 1 of the present embodiment having the above-described configuration forms a magnetic circuit between the stator teeth 22 and the stator base 21 and the permanent magnet 5 when an excitation current is supplied to the stator coil 23, and each stator By appropriately changing the intensity of the exciting current supplied to the coil 23, the entire rotor 3 can be rotated at high speed around the axis 3J (of course, low-speed rotation is also possible depending on the specification, application, etc.).

  Here, when an exciting current is supplied to the stator coil 23, an eddy current is generated on the outer surface of the permanent magnet 5, and a magnetic field is generated in the permanent magnet 5 in a direction opposite to the magnetizing direction (magnetizing direction) of the magnet. A so-called demagnetizing field may occur. In particular, there is a tendency for a strong demagnetizing field to appear in a portion where the “magnet thickness” which is the length in the magnetization direction of the unit magnets 6, in other words, the length in the direction orthogonal to the arrangement direction 6 </ b> A of the unit magnets 6 is thin. Such a demagnetizing field acts to weaken the magnetization of the magnet itself. When a plurality of unit magnets 6 magnetized in parallel orientation are arranged in the circumferential direction of the shaft 4 to constitute the permanent magnet 5, the unit magnets 6 are arranged in the central region 3C of the rotor 3 in the arrangement direction 6A of the unit magnets 6. The center-side unit magnet 61 whose surface (inward surface) opposite to the surface constituting the magnetic pole can be in surface contact with the shaft 4 is compared with the side-side unit magnet 62 that cannot be in surface contact with the shaft 4, In design, the magnet thickness must be set relatively thin, which may cause a strong demagnetizing field.

  However, in the rotating machine 1 according to the present embodiment, the magnet width 61W of the center-side unit magnet 61 is set smaller (shorter) than the magnet width 62W of the side-side unit magnet 62. The demagnetizing field can be reduced. This is because the ratio of the magnet thickness to the area of the outer surface of the center unit magnet 61 is increased by setting the magnet width 61W of the center unit magnet 61 shorter than the magnet width 62W of the side unit magnet 62. This is based on the technical idea of increasing the permeance coefficient determined by the ratio of the magnet thickness to the surface area. Thus, if the magnet width 61W of each center side unit magnet 61 is reduced and the permeance coefficient is increased, the demagnetizing field coefficient is decreased and the demagnetizing field can be reduced. Further, by reducing the magnet width 61W of each center-side unit magnet 61, the outer surface area of each center-side unit magnet 61 is also reduced, so that the amount of eddy current generated can be reduced, and the temperature rise due to eddy current. It is possible to suppress the demagnetization associated with the temperature rise, and it is possible to suppress the magnetic field in the opposite direction due to the eddy current.

  The rotating machine 1 according to the present embodiment having such a configuration can effectively reduce eddy currents by increasing the number of divisions of the permanent magnets 5 (the number of unit magnets 6). The temperature increase can be suppressed, the demagnetization accompanying the temperature increase can be suppressed, the magnetic field in the opposite direction due to the eddy current can also be suppressed, and the permeance coefficient of each unit magnet 61, 62 can be increased. A demagnetizing field can be suppressed. Therefore, it is possible to effectively prevent / suppress the situation that can occur when the demagnetizing field appears strongly and the magnetic force becomes small, that is, the operating efficiency is reduced and unnecessary heat is generated.

  In addition, when it is necessary to set the outer diameter of the entire rotor 3 to be small while applying the thick shaft 4 so as to cope with high-speed rotation, the magnet thickness of each unit magnet 6 must be set thin. In such a case, the center-side unit magnet 61 is thinner than the side-side unit magnet 62, and thus has a shape that is particularly susceptible to demagnetizing fields.

  However, in the rotating machine 1 according to the present embodiment, as described above, the magnet width 61W of the center-side unit magnet 61 is set to be smaller than the magnet width 62W of the side-side unit magnet 62, and further, The permeance coefficient of the center side unit magnet 61 is increased by setting the magnet width 61W to one half or less of the magnet thickness of the center side unit magnet 61W, more specifically about one third to one fourth. In addition, the demagnetizing field can be reduced. Therefore, by using the rotating machine 1 according to the present embodiment, the thick shaft 4 is applied and the outer diameter of the rotor 3 itself is set small, but it is hardly affected by the demagnetizing field, and the operation efficiency is reduced and heat is generated. It can be suitably prevented and suppressed.

  Further, when the rotor 3 having two magnetic poles is constituted by the permanent magnet 5 as in the rotating machine 1 of the present embodiment, the permanent magnet 5 has the condition that the outer diameter of the rotor 3 is reduced. Compared to the case of configuring a multipolar rotor 3 having, for example, four or more magnetic poles, the magnet per pole is large (corresponding to half of the shaft 4 (180 degrees)), so the magnet thickness must be reduced. There is a restriction that it must be done. However, in the rotating machine 1 according to the present embodiment, even if the magnet thickness of the unit magnet 6 constituting the permanent magnet 5 has to be set thin, the magnet width 61W of the center side unit magnet 61 is set to the side unit. By setting the magnet 62 to be narrower than the magnet width 62W and increasing the number of magnet divisions in the central region of the rotor 3 in the arrangement direction 6A of the unit magnets 6, temperature rise due to eddy current can be suppressed and eddy current can be suppressed. The magnetic field in the opposite direction due to the current can also be suppressed, and further, the demagnetizing field can be reduced by increasing the permeance coefficient determined by the shape of the magnet.

  In addition, this invention is not limited to embodiment mentioned above. For example, the number of divisions of the permanent magnet can be changed as appropriate. At this time, the center-side unit magnet and the side-side unit magnet are within a range satisfying the condition that the magnet width of the center-side unit magnet is smaller than the maximum magnet width of the side-side unit magnet (hereinafter referred to as “magnet width condition”). The magnet width can be changed as appropriate.

  Moreover, in the above-mentioned embodiment, although the magnet width of each center side unit magnet was set to be the same and the magnet width of each side side unit magnet was set to be the same, if the magnet width condition is satisfied, A mode in which the side unit magnets have different magnet widths or the side unit magnets have different magnet widths may be used. In this case, if the magnet width condition is satisfied, the magnet width of the center unit magnet is “the minimum magnet width of the side unit magnet” (the side end unit having the shortest length in the arrangement direction among the plurality of side unit magnets). It may be larger than the magnet width of the magnet.

  In addition, a shaft having a polygonal shape (for example, a hexagonal shape, an octagonal shape, or the like) can also be used as a shaft. According to the cross-sectional shape of the shaft, the outer surface constituting the magnetic pole in the center unit magnet What is necessary is just to change suitably the surface (inward surface) on the opposite side according to the shape of the outer surface of a shaft.

  Moreover, you may be a rotary machine which accommodated the rotor and the stator in the common casing.

  In addition, the rotating machine of the present invention can be used as a dynamometer, a large-capacity high-speed motor, a large-capacity high-speed generator, etc. for an automobile test apparatus.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Rotating machine 2 ... Stator
3 ... Rotor
4 ... Shaft 5 ... Permanent magnet 6 ... Unit magnet 61 ... Center side unit magnet 61W ... Center side unit magnet width 62 ... Side side unit magnet 62W ... Side width unit magnet width

Claims (3)

A rotor having a shaft and a permanent magnet attached to the outer surface of the shaft and constituting a magnetic pole;
A rotating machine that includes a stator that accommodates the rotor in an internal space and cannot rotate,
The permanent magnet is a parallel anisotropic magnet in which a plurality of unit magnets are arranged in the circumferential direction of the shaft and the magnetization direction of all the unit magnets is set in a direction orthogonal to the arrangement direction,
Of the unit magnets, the surface opposite to the surface constituting the magnetic pole, which is disposed in the central region of the rotor in the arrangement direction of the unit magnets, is orthogonal to the magnetization direction of the unit magnets that can contact the shaft. A rotating machine, wherein a magnet width, which is a length in a direction, is set smaller than a maximum magnet width of unit magnets arranged in a side end region of the rotor in the arrangement direction. The shaft is substantially cylindrical,
The unit magnets arranged in the central region of the rotor in the arrangement direction of the unit magnets correspond to the diameter range of the shaft,
2. The rotating machine according to claim 1, wherein unit magnets arranged in a side end region of the rotor in the arrangement direction correspond to outside the diameter range of the shaft. The magnet width of the unit magnet arrange | positioned at the center part area | region of the said rotor is set to the half or less of the magnet thickness which is the length of the magnetization direction of the said unit magnet. Rotating machine.

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