JP2020038026A - Magnetic refrigeration device - Google Patents

Abstract

To suppress variations in density distribution of a magnetic flux penetrating magnetic working substances on the magnetic working substances.SOLUTION: A magnetic refrigeration device includes: a yoke having an opening; a magnetic working body which is disposed on an inner peripheral surface of the yoke, and includes magnetic working substances; and a rotator which is disposed in the inside of the opening of the yoke, and rotates about a rotation axis. The rotator is equipped with a permanent magnet that is magnetized in any direction of diametrical directions when viewed from the rotation axis direction and has a pole surface at an end portion in a magnetizing direction, and an opposite distance between the pole surface at the center in a circumferential direction of the pole surface with respect to the rotation axis and the magnetic working body is longer than an opposite distance between the pole surface at the end portion in the circumferential direction and the magnetic working body.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a magnetic refrigerator.

  In recent years, attention has been paid to a magnetic refrigerator as one of refrigeration techniques. It is said that the magnetic refrigerating apparatus does not use Freon gas or the like and has little influence on the environment.

  An AMR (Active Magnetic Regenerative Refrigeration) method is known as one of the magnetic refrigeration techniques used for a magnetic refrigeration apparatus (for example, Patent Document 1). The AMR method is a refrigeration technology using a magnetocaloric effect and a heat storage effect.

  The magnetocaloric effect is a physical phenomenon in which a magnetic material generates or absorbs heat with a change in magnetic entropy in the magnetic material. When a magnetic field is applied to a magnetic body in an adiabatic state, the magnetic entropy decreases. As a result, the magnetic body generates heat, and the temperature of the magnetic body rises. On the other hand, when the magnetic field applied to the magnetic body is removed, the magnetic entropy increases. As a result, the magnetic material absorbs heat, and the temperature of the magnetic material decreases.

  On the other hand, the heat storage effect is a physical phenomenon utilizing a change in entropy of a crystal lattice in a magnetic body. When a magnetic field is applied to the magnetic material in an adiabatic state, the entropy of the crystal lattice increases, and when the magnetic field is removed, the entropy of the crystal lattice decreases. By actively utilizing the entropy of the crystal lattice, which can be a hindrance to magnetic refrigeration in the room temperature range, the generated cold heat can be efficiently stored.

  Patent Literature 2 describes a magnetic refrigeration apparatus including a rotor to which a permanent magnet is fixed, and a stator having a magnetic working body having a magnetic working substance on an inner surface side. When the rotor rotates inside the stator, two states are created: an applied state in which a magnetic field is applied to the magnetic working material and a non-applied state in which the magnetic field applied to the magnetic working material is removed. The magnetic working material cools the object to be cooled when transitioning from the applied state to the non-applied state.

JP 2014-98495 A JP 2008-51412 A

  In the magnetic refrigeration apparatus described in Patent Literature 2, the magnetic pole surface of the permanent magnet has an arc shape reflecting the inner peripheral surface of the opposed stator. When the pole face draws a predetermined arc, the distance between the pole face and the magnetic work body changes for each position of the pole face. For example, the distance between the pole face of the permanent magnet and the magnetic work body at the center is shorter than the distance between the pole face of the permanent magnet and the magnetic work body at the end. The magnetic flux density of the permanent magnet is affected by the distance between the magnetic pole surface of the permanent magnet and the magnetic working body. The magnetic flux density at the center of the permanent magnet is high and the magnetic flux density at the end of the permanent magnet is low. That is, in the applied state where the magnetic field is applied, the magnetic flux density distribution penetrating the magnetic work material varies.

  When a permanent magnet having a variation in magnetic flux density distribution rotates, a time difference occurs in a change in magnetic entropy at the time of excitation. This time difference causes a problem that a part of the magnetic working material causes an endothermic phenomenon when removing heat from the heated magnetic working material. When the heat generation phenomenon and the heat absorption phenomenon occur simultaneously, the magnetocaloric effect as a whole decreases.

  The present invention has been made in view of the above problems, and has as its object to suppress variations in the density distribution of magnetic flux penetrating a magnetic work material.

As a result of intensive studies, the present inventors have found that by adjusting the shape of the permanent magnet that is the source of the magnetic flux, it is possible to suppress variations in the density distribution of the magnetic flux penetrating the magnetic working body.
That is, the present invention provides the following means in order to solve the above problems.

(1) A magnetic refrigeration apparatus according to a first aspect, wherein a yoke having an opening, a magnetic working body located on an inner peripheral surface of the yoke and containing a magnetic working material, and a yoke having an opening inside the opening of the yoke. And a rotor that rotates about a rotation axis, wherein the rotor is magnetized in one of radial directions as viewed from the rotation axis direction in which the rotation axis extends, and has a magnetization direction. A permanent magnet having a magnetic pole surface at an end of the magnetic pole, and a facing distance between the magnetic pole surface and the magnetic work body at a center in a circumferential direction of the magnetic pole surface with respect to the rotation axis is the distance at the end in the circumferential direction. It is longer than the facing distance between the magnetic pole surface and the magnetic work body.

(2) In the magnetic refrigerator according to the above aspect, the magnetic pole surface may be a flat surface or a convex surface viewed from the rotation axis.

(3) In the magnetic refrigeration apparatus according to the above aspect, a facing distance between the magnetic pole surface and the magnetic working body may be asymptotically shorter from the center of the magnetic pole surface in the circumferential direction toward an end.

(4) In the magnetic refrigerating apparatus according to the above aspect, the rotor may further include a magnetic flux control unit, and may be located outside the magnetic pole surface with respect to the rotation axis and include a magnetic body.

(5) In the magnetic refrigeration apparatus according to the above aspect, a thickness of the magnetic flux control unit at the center in the circumferential direction may be larger than a thickness of the magnetic flux control unit at an end in the circumferential direction.

(6) In the magnetic refrigeration apparatus according to the above aspect, the thickness of the magnetic flux control section may be asymptotically reduced from the center in the circumferential direction toward the end.

  According to the magnetic refrigeration apparatus of the above aspect, it is possible to suppress the variation in the density distribution of the magnetic flux penetrating the magnetic work material.

It is a schematic diagram of the magnetic refrigeration system according to the first embodiment. It is the figure which showed typically the cross section of the magnetic refrigeration apparatus concerning 1st Embodiment. It is a figure showing typically operation of a magnetic refrigerating device concerning a 1st embodiment. It is the figure which showed typically the cross section of another example of the magnetic refrigerator concerning 1st Embodiment. It is the figure which showed typically the cross section of another example of the magnetic refrigerator concerning 1st Embodiment. It is the figure which showed typically the cross section of the magnetic refrigerator of the magnetic refrigerator system concerning 2nd Embodiment. It is a schematic diagram of the A model used when simulating the magnetic flux density distribution. It is a schematic diagram of a B model used when simulating a magnetic flux density distribution. It is a schematic diagram of the C model used when simulating the magnetic flux density distribution. It is the result of measuring the magnetic flux density distribution in the vicinity of the inner peripheral surface of the yoke in Examples 1 to 6 and Comparative Example 1.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings as appropriate. In the drawings used in the following description, a characteristic part may be enlarged for convenience in order to make the characteristic easy to understand, and the dimensional ratio of each component may be different from the actual one. The materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not limited thereto, and can be appropriately modified and implemented within a range in which the effects of the present invention are exhibited.

"First Embodiment"
(Magnetic refrigeration system)
FIG. 1 is a schematic diagram of a magnetic refrigeration system according to the first embodiment. The magnetic refrigeration system 200 shown in FIG. 1 includes a magnetic refrigeration apparatus 100, a pump 110, switching units 120 and 121, a cooling chamber 130, a storage tank 140, and a flow path 150. The magnetic refrigeration apparatus 100, the pump 110, the switching units 120 and 121, the cooling chamber 130, and the storage tank 140 are connected by a flow path 150.

  Pump 110 circulates the heat exchange medium. The heat exchange medium is not limited to water, but may be another solution, air, or the like. The heat exchange medium discharged from the pump 110 is supplied to the switching unit 120 via the flow path 150 (flow F1).

  The switching units 120 and 121 control where the heat exchange medium is supplied to the magnetic refrigeration apparatus 100, and switch the connection of the flow path 150. The heat exchange medium discharged from the switching unit 120 is supplied to the magnetic refrigerator 100 via the flow path 150 (flow F2). The heat exchange medium is supplied to the magnetic working body 20 in the magnetic refrigerator 100 to which no magnetic field is applied, and the heat exchange medium is cooled.

  The cooling chamber 130 has a cooling unit 132. The cooled heat exchange medium is supplied to the cooling unit 132 of the cooling chamber 130 via the flow path 150 (flow F3). The heat exchange medium cools the inside of the cooling chamber 130 and absorbs heat. The heat exchange medium that has absorbed the heat is supplied again to the magnetic refrigerator 100 (flow F4). The heat exchange medium is supplied to the magnetic working body 20 of the magnetic refrigeration apparatus 100 to which the magnetic field is applied, via the channel 150. The flow channel 150 is selected by the switching unit 121. The magnetic working body 20 warms the heat exchange medium. By transmitting heat to the heat exchange medium, the temperature of the magnetic working body 20 is prevented from increasing. The warmed heat exchange medium is supplied to the storage tank 140 via the flow path 150 (flow F5).

  The storage tank 140 stores a heat exchange medium. The heat exchange medium warmed by the magnetic working body 20 is cooled to room temperature in the storage tank 140. The heat exchange medium cooled to room temperature reaches the pump 110 from the storage tank 140 (flow F6). The magnetic refrigeration system 200 circulates once through the flow F1 to the flow F6 described above. The magnetic refrigeration system 200 repeats this circulation to cool the object to be cooled in the cooling chamber 130.

(Magnetic refrigerator)
FIG. 2 is a schematic cross-sectional view of the magnetic refrigerator 100 according to the first embodiment. FIG. 2 corresponds to a section obtained by cutting the magnetic refrigeration apparatus 100 in a section perpendicular to the rotation shaft 32 described later. The magnetic refrigeration apparatus 100 includes a yoke 10, a magnetic work body 20, and a rotor 30.

  The yoke 10 has an opening 10A inside. The yoke 10 is a cylindrical member extending in one direction as shown in FIG. The yoke 10 is made of a magnetic material. For the yoke 10, for example, a steel material for general structure (SS400), a silicon steel plate, a carbon material for machine structure, or the like can be used.

  The magnetic working body 20 is located on the inner peripheral surface 10 a of the yoke 10. The magnetic working body 20 may be in contact with the inner peripheral surface 10a of the yoke 10, or may be arranged at intervals.

  The magnetic working body 20 shown in FIG. 2 is divided into a plurality of regions by a partition plate 22 extending in the same direction as the direction in which the yoke 10 extends. The magnetic working body 20 may be provided on the entire inner peripheral surface 10a of the yoke 10 as shown in FIG. 2, or may be provided only on a part thereof. For example, a plurality of magnetic working bodies 20 may be arranged on the inner peripheral surface 10a of the yoke 10 at regular intervals.

  The magnetic working body 20 has a magnetic working material. The magnetic working material is made of a material that exhibits a magnetocaloric effect. The magnetic working material generates heat when a magnetic field is applied in an adiabatic state, and absorbs heat when the applied magnetic field is removed. The magnetic entropy of the magnetic working material changes between an applied state where a magnetic field is applied and a non-applied state where the applied magnetic field is removed, and the magnetic working material generates or absorbs heat.

Magnetic working substance, for _example, can be used Gd 5 _{Si 2} Ge 2 based materials, Mn (As-Sb) based material, MnFe (P-As) based material, a La (Fe-Si) H-based material or the like.

  The rotor 30 is located in the opening 10 </ b> A of the yoke 10. The rotor 30 shown in FIG. 2 includes a permanent magnet 31 and a rotating shaft 32. The center of the rotation shaft 32 coincides with the center of the yoke 10. The rotor 30 rotates about a rotation shaft 32.

  The permanent magnet 31 is magnetized in the radial direction when viewed from the direction of the rotation axis where the rotation shaft 32 extends. At the end in the magnetization direction (radial direction), a magnetic pole surface 31a is provided. The magnetic pole surface 31 a is a surface of the outer surface of the permanent magnet 31 through which a magnetic flux penetrates.

  The permanent magnet 31 shown in FIG. 2 has a long axis and a short axis when viewed from the rotation axis direction. The cross-sectional shape of the permanent magnet 31 is not limited to this case. The first direction of the permanent magnet 31 shown in FIG. 2 is the long axis direction of the permanent magnet 31 and is magnetized in the long axis direction.

  The facing distance L1 between the magnetic pole surface 31a and the magnetic working body 20 at the center in the circumferential direction of the permanent magnet 31 is longer than the facing distance L2 between the magnetic pole surface 31a and the magnetic working body 20 at the circumferential end. Here, the facing distance means a distance of a perpendicular line that is lowered from the magnetic pole surface 31a toward the magnetic working body 20 along the magnetization direction. The magnetic pole surface 31a passes through the end of the permanent magnet 31 and is located closer to the rotation shaft 32 than the reference surface S1 equidistant from the magnetic work body 20.

  The magnetic flux density at each position of the magnetic working body 20 is determined by the magnetomotive force generated by the permanent magnet 31 and the distance between the magnetic pole surface 31a and the magnetic working body 20.

  When the magnetic pole surface 31a is located on the reference surface S1, the distance in the magnetizing direction between the magnetic pole surface 31a and the magnetic working body 20 is longer at the end than at the center in the circumferential direction. The magnetic flux density at each position of the magnetic working body 20 changes according to the distance between the magnetic pole surface 31a and the magnetic working body 20. The magnetic flux density at each position of the magnetic working body 20 is stronger at the position facing the center than at the position facing the end of the magnetic pole surface 31a, and the magnetic flux density at each position of the magnetic working body 20 varies.

  On the other hand, in the magnetic refrigeration apparatus 100 shown in FIG. 2, the facing distance L1 between the magnetic pole surface 31a at the center in the circumferential direction and the magnetic working body 20 is equal to the distance between the magnetic pole surface 31a at the circumferential end and the magnetic working body 20. It is longer than the facing distance L2. That is, from the magnetic pole surface 31a to the magnetic work body 20, the magnetic flux is diffused from the circumferential end at the circumferential center of the magnetic pole surface 31a.

  Therefore, by controlling the distance between the magnetic pole surface 31a and the magnetic work body 20, the variation in the magnetic flux density at each position of the magnetic work body 20 facing the magnetic pole surface 31a is suppressed.

  The magnetic pole surface 31 a of the permanent magnet 31 shown in FIG. 2 is a convex surface projecting from the rotation shaft 32. As shown in FIG. 2, the shape of the magnetic pole surface 31a preferably changes asymptotically from the center in the circumferential direction toward the end. As the shape of the magnetic pole surface 31a changes asymptotically, the facing distance between the magnetic pole surface 31a and the magnetic work body 20 asymptotically decreases from the circumferential center of the magnetic pole surface 31a toward the end. Here, “asymptotically” means that the shape gradually changes, and also includes the case where the shape of the magnetic pole surface 31a and the facing distance change stepwise. The variation of the magnetic flux density at each position of the magnetic working body 20 facing the magnetic pole surface 31a is further suppressed by asymptotically changing the shape and the facing distance of the magnetic pole surface 31a.

  FIG. 3 is a diagram schematically illustrating the operation of the magnetic refrigeration apparatus 100 according to the first embodiment. The magnetic refrigeration apparatus 100 heats and absorbs the magnetic working material inside the magnetic working body 20 by rotating the rotor 30 to heat and cool the heat exchange medium flowing inside the magnetic working body 20.

  FIG. 3A is a diagram schematically illustrating a cross section of the magnetic refrigeration apparatus 100 at an arbitrary time. The magnetic working body 20 shown in FIG. 3 is divided into six regions. The magnetic flux lines are generated between the magnetic pole surface 31a and the yoke 10. Therefore, at any given time, the magnetic field is applied to the magnetic work substance inside the magnetic work body 20 in the first region 20A among the six divided regions. The magnetic entropy of the magnetic working material inside the first region 20A decreases. That is, the magnetic work material inside the first region 20A generates heat.

  Since there are two magnetic pole surfaces 31a in the radial direction, two first regions 20A also exist at opposing positions. Hereinafter, the area adjacent to the first area 20A in the clockwise direction is referred to as a second area 20B, and the area adjacent to the first area 20A is referred to as a third area 20C.

  Next, when the rotor 30 rotates, the magnetic refrigerator 100 transitions from the state of FIG. 3A to the state of FIG. 3B. FIG. 3B is a diagram schematically illustrating a cross section of the magnetic refrigerator 100 at another arbitrary time. In the state of FIG. 3B, the magnetic field is applied to the magnetic work material inside the second region 20B. The magnetic work material inside the second region 20B generates heat.

  On the other hand, the magnetic field applied to the first region 20A in FIG. 3A is removed. Therefore, the magnetic entropy of the magnetic work material inside the first region 20A increases. As a result, the magnetic work material inside the first region 20A absorbs heat.

  When shifting from the state of FIG. 3A to the state of FIG. 3B, the flow path 150 for supplying the heat exchange medium from the switching unit 120 to the magnetic refrigeration apparatus 100 is connected to the first region 20A, and the magnetic refrigeration is performed. The flow path 150 for discharging the heat exchange medium from the device 100 to the switching unit 120 is connected to the second region 20B.

  Since the magnetic working material in the first region 20A shows an endothermic reaction at this moment, the heat exchange medium supplied to the magnetic refrigerator 100 is cooled. The cooled heat exchange medium is supplied to the cooling chamber 130 to cool the object to be cooled. The magnetic working material in the second region 20B shows an exothermic reaction at this moment, but is prevented from being heated to a high temperature by heating the heat exchange medium returning to the storage tank 140.

  As the rotor 30 rotates, the area of the magnetic working body 20 to which the magnetic field is applied changes sequentially to the first area 20A, the second area 20B, and the third area 20C. The flow path 150 is switched by the switching units 120 and 121 according to this change. The heat exchange medium flowing to the cooling chamber 130 is always cooled, and the object to be cooled is efficiently cooled.

  The magnetic refrigeration apparatus 100 according to the first embodiment has a small variation in the magnetic flux density applied to the first region 20A, the second region 20B, and the third region 20C. In other words, the switching between the applied state in which the magnetic field is applied to the magnetic working substance and the non-applied state in which the magnetic field applied to the magnetic working substance is removed becomes clear, and the heat generation and endothermic phenomena occur simultaneously in one region. This can be suppressed. As a result, the magnetocaloric effect of the magnetic working body 20 as a whole is efficiently exhibited.

  As described above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited to the specific embodiments, and various modifications may be made within the scope of the present invention described in the appended claims. Can be modified and changed.

  FIG. 4 is a schematic cross-sectional view of another example of the magnetic refrigerator according to the first embodiment. The magnetic refrigeration apparatus 101 shown in FIG. 4 differs from the magnetic refrigeration apparatus 100 shown in FIG. Other configurations are the same as those of the magnetic refrigerator 100 shown in FIG. The same components are denoted by the same reference numerals, and description thereof will be omitted.

  The permanent magnet 33 shown in FIG. 4 is a rectangle having a long axis and a short axis when viewed from the rotation axis direction. Therefore, the magnetic pole surface 33 a is a flat surface viewed from the rotation shaft 32.

  In the permanent magnet 33 shown in FIG. 4, the thickness in the magnetizing direction at the center in the circumferential direction of the magnetic pole face 33a matches the thickness in the magnetizing direction at the circumferential end of the magnetic pole face 33a. The facing distance L1 between the magnetic pole surface 33a and the magnetic working body 20 at the center in the circumferential direction is longer than the facing distance L2 between the magnetic pole surface 33a and the magnetic working body 20 at the circumferential end. That is, from the magnetic pole surface 33a to the magnetic working body 20, the magnetic flux is diffused from the circumferential end at the circumferential center.

  In this case, the magnetic flux density of the magnetic working body 20 at a position facing the center of the magnetic pole surface 33a in the second direction is smaller than the magnetic flux density of the magnetic working body 20 at a position facing the end of the magnetic pole surface 33a in the second direction. Become. However, the variation of the magnetic flux density at each position of the magnetic working body 20 facing the magnetic pole surface 31a is suppressed as compared with the case where the magnetic pole surface 33a is located on the reference surface S1.

  The case where the magnetic pole surface 31a is convex with respect to the rotating shaft 32 (FIG. 2) and the case where the magnetic pole surface 33a is flat (FIG. 4) have been described. The shape of the magnetic pole surface may be concave with respect to the rotation shaft 32 as long as the effect is obtained. On the other hand, from the viewpoint of increasing the magnetic flux density and suppressing variations, it is preferable that the magnetic pole surface be flat or convex as described above.

  FIG. 5 is a schematic cross-sectional view of another example of the magnetic refrigerator according to the first embodiment. The magnetic refrigeration apparatus 102 shown in FIG. 5 differs from the magnetic refrigeration apparatus 100 shown in FIG. Other configurations are the same as those of the magnetic refrigerator 100 shown in FIG. The same components are denoted by the same reference numerals, and description thereof will be omitted.

  The rotor 40 shown in FIG. 5 has a rotating shaft 42, a support 43, and a plurality of permanent magnets 44. The plurality of permanent magnets 44 are supported by the support 43. By supporting the permanent magnets 44 on the four sides of the support 43, the permanent magnets 44 protrude in four radial directions with respect to the rotation shaft 42. The plurality of permanent magnets 44 are magnetized in the direction in which they protrude from the support 43.

  Each of the plurality of permanent magnets 44 has a magnetic pole surface 44 a at a position facing the magnetic work body 20. In each magnetic pole surface 44a, the facing distance L1 between the magnetic pole surface 44a and the magnetic work body 20 at the center in the circumferential direction is longer than the facing distance L2 between the magnetic pole surface 44a and the magnetic work body 20 at the circumferential end. That is, from the magnetic pole surface 44a to the magnetic work body 20, the magnetic flux is diffused from the circumferential end at the circumferential center. As a result, variation in magnetic flux density at each position of the magnetic working body 20 facing the magnetic pole surface 44a is suppressed.

  The number of magnetic pole faces in the magnetic refrigerator is not limited to the two cases shown in FIGS. 2 and 4 and the four cases shown in FIG. 5, but an arbitrary number can be selected.

"Second embodiment"
FIG. 6 is a schematic cross-sectional view of the magnetic refrigerator 103 according to the second embodiment. The magnetic refrigerator 103 according to the second embodiment is different from the magnetic refrigerators 100 and 101 according to the first embodiment in that the rotor 30 further includes a magnetic flux controller 35. Other configurations are the same as those of the magnetic refrigerator 100 shown in FIG. The same components are denoted by the same reference numerals, and description thereof will be omitted.

  The rotor 30 includes a rotating shaft 32, a permanent magnet 34, and a magnetic flux control unit 35. The permanent magnet 34 shown in FIG. 6 is a rectangle having a major axis and a minor axis when viewed from the rotation axis direction, and the pole face 34a is a flat surface. The facing distance L1 between the magnetic pole surface 34a and the magnetic working body 20 at the center in the circumferential direction is longer than the facing distance L2 between the magnetic pole surface 34a and the magnetic working body 20 at the circumferential end. The shape of the permanent magnet 34 in a plan view from the rotation axis direction may be the same as the permanent magnet 31 shown in FIG.

  The magnetic flux control unit 35 is located outside the magnetic pole surface 34a with respect to the rotation axis 32. The magnetic flux control unit 35 has a ferromagnetic material.

  When the magnetic flux control unit 35 is a ferromagnetic material, the magnetic permeability of the ferromagnetic material is higher than the magnetic permeability of air. That is, the change in the magnetic flux density between the magnetic pole surface 34a and the opposing surface 35a is reduced as compared with the case where no ferromagnetic material is provided. As a result, the magnetic flux penetrating the center of the magnetic pole surface 34 a in the circumferential direction is suppressed from diffusing to the magnetic working body 20. When the diffusion of the magnetic flux is suppressed, a decrease in the magnetic flux density at a position facing the center of the magnetic pole surface 34a of the magnetic working body 20 in the second direction is suppressed, and the variation in the magnetic flux density is further suppressed.

  The thickness at the circumferential center of the magnetic flux control unit 35 is preferably greater than the thickness at the circumferential end of the magnetic flux control unit 35, and is preferably asymptotically thinner from the circumferential center toward the end. . For example, as shown in FIG. 6, it is preferable that the opposing surface 35a of the magnetic flux controller 35 draws an arc.

  The position of the opposing surface 35a of the magnetic flux control unit 35 may coincide with the reference surface S1, may be located closer to the rotation axis 32 than the reference surface S1, or may be further away from the rotation shaft 32 than the reference surface S1. May be located at different positions. Also in the second embodiment, the number of the pole faces 34a is not limited to two.

  As described above, according to the magnetic refrigeration apparatus 103 according to the second embodiment, it is possible to further suppress the variation in the magnetic flux density at each position of the magnetic working body 20 facing the magnetic pole surface 34a.

  7 to 9 show models used for simulating the magnetic flux density distribution. The simulation was performed using three-dimensional finite element method electromagnetic field analysis software. In order to facilitate the calculation, only a semicircle centered on the rotation axis 32 was modeled and simulated. Magnetic working bodies that do not significantly affect the magnetic flux density distribution were removed from the model. Hereinafter, the model of FIG. 7 is referred to as an A type, the model of FIG. 8 is referred to as a B type, and the model of FIG. 9 is referred to as a C type.

  The yoke 10 was a steel material for general structure (SS400) having a thickness D10 of 33 mm. In each of the A type, the B type, and the C type, the rotor 30 includes a rotating shaft 32, a first portion 36, a second portion 37, and a third portion 38. The first portion 36 was made of a neodymium magnet (NEOREC50B), and the third portion 38 was made of SS400. The distance between the opposing surface 37a of the second portion 37 and the inner peripheral surface of the yoke 10 was fixed, and the configuration of the second portion 37 was changed for each example.

  The A-type magnetic pole surface 36a is a surface in which an arc and a flat surface are combined. The B-type magnetic pole surface 36a is a surface formed by an arc. The C-type magnetic pole surface 36a is a surface in which a circular arc and an inclined surface are combined. In each case, the facing distance L3 between the magnetic pole surface 36a and the yoke 10 at the center in the circumferential direction is longer than the facing distance L4 between the magnetic pole surface 36a and the yoke 10 at the circumferential end. Since the magnetic working body exists along the inner peripheral surface of the yoke, the facing distance between the magnetic pole surface 36a and the yoke 10 corresponds to the facing distance between the magnetic pole surface 36a and the magnetic working body.

"Example 1"
In Example 1, the second portion 37 was a gap in the A type. That is, this corresponds to the case where the second portion 37 of the rotor 30 is shaved and removed. The facing distance L3 between the magnetic pole surface 36a and the yoke 10 at the center in the circumferential direction was 22.5 mm, and the facing distance L4 between the magnetic pole surface 36a and the yoke 10 at the circumferential end was 17.0 mm. The thickness D1 at the center in the circumferential direction of the first portion 36, which is a permanent magnet, was 52.0 mm, and the thickness D2 at the end in the second direction was 47.5 mm.

"Example 2"
The second embodiment differs from the first embodiment in that the second portion 37 in the A type is made of a general structural steel material (SS400). Other conditions were the same as in Example 1.

"Example 3"
In Example 3, the second portion 37 was a void in the B type. That is, this corresponds to the case where the second portion 37 of the rotor 30 is shaved and removed. The facing distance L3 between the magnetic pole surface 36a and the yoke 10 at the center in the circumferential direction was 20.5 mm, and the facing distance L4 between the magnetic pole surface 36a and the yoke 10 at the circumferential end was 17.0 mm. The thickness D1 at the center in the circumferential direction of the first portion 36, which is a permanent magnet, was 54.1 mm, and the thickness D2 at the end in the circumferential direction was 47.5 mm.

"Example 4"
The fourth embodiment is different from the third embodiment in that the second portion 37 of the B type is a steel material for general structure (SS400). Other conditions were the same as in Example 3.

"Example 5"
In Example 5, the second portion 37 was a void in the C type. That is, this corresponds to the case where the second portion 37 of the rotor 30 is shaved and removed. The facing distance L3 between the magnetic pole surface 36a and the yoke 10 at the center in the circumferential direction was 17.5 mm, and the facing distance L4 between the magnetic pole surface 36a and the yoke 10 at the circumferential end was 17.0 mm. The thickness D1 at the center in the circumferential direction of the first portion 36, which is a permanent magnet, was 57.0 mm, and the thickness D2 at the end in the circumferential direction was 47.5 mm.

"Example 6"
The sixth embodiment is different from the fifth embodiment in that the second portion 37 of the C type is made of a general structural steel material (SS400). Other conditions were the same as in Example 5.

"Comparative Example 1"
In Comparative Example 1, the second portion 37 of the A type was a neodymium magnet. That is, both the first portion 36 and the second portion 37 are made of a neodymium magnet and are integrated. The magnetic pole surface in this case is the facing surface 37a of the second portion 37. The opposing distance L3 between the opposing surface 37a (magnetic pole surface) and the yoke 10 at the center in the circumferential direction is 14.5 mm, and the opposing distance L4 between the opposing surface 37a (magnetic pole surface) and the yoke 10 at the circumferential end is 17. 0 mm. The thickness D1 at the center in the circumferential direction of the portion where the first portion 36 and the second portion 37, which are permanent magnets, were combined was 60.0 mm, and the thickness D2 at the end in the second direction was 47.5 mm. The case where the second portion 37 of the B type or the C type is a neodymium magnet is the same as that of the comparative example 1.

  Table 1 below summarizes each configuration of Examples 1 to 6 and Comparative Example 1. FIG. 10 summarizes the results of measuring the magnetic flux density distribution in the vicinity of the inner peripheral surface of the yoke in Examples 1 to 6 and Comparative Example 1. As shown in FIG. 10, in each of the examples, the variation of the magnetic flux density in the portion where the magnetic field was applied was suppressed as compared with Comparative Example 1.

10 Yoke 10a Inner peripheral surface 10A Opening 20 Magnetic working body 20A First area 20B Second area 20C Third area 22 Partition plate 30 Rotors 31, 33, 34, 44 Permanent magnets 31a, 33a, 34a, 36a, 44a Magnetic poles Surfaces 32, 42 Rotation shaft 43 Support 35 Magnetic flux control unit 35a, 37a Opposing surface 36 First part 37 Second part 38 Third part 100, 101, 102, 103 Magnetic refrigeration unit 110 Pump 120, 121 Switching unit 122 Rotary valve 130 Cooling room 132 Cooling unit 140 Storage tank 150 Flow path F1, F2, F3, F4, F5, F6 Flow S1 Reference plane L1, L2 Opposing distance D1, D2 Thickness

Claims (6)

A yoke having an opening,
A magnetic working body located on the inner peripheral surface of the yoke and including a magnetic working material;
A rotor that is located inside the opening of the yoke and rotates around a rotation axis,
The rotor is provided with a permanent magnet that is magnetized in any direction in a radial direction when viewed from a rotation axis direction in which the rotation axis extends, and has a pole face at an end in the magnetization direction.
The facing distance between the magnetic pole surface and the magnetic working body at the center in the circumferential direction of the magnetic pole surface with respect to the rotation axis is longer than the facing distance between the magnetic pole surface and the magnetic working body at the circumferential end. , Magnetic refrigeration equipment.   The magnetic refrigeration apparatus according to claim 1, wherein the magnetic pole surface is a flat surface or a convex surface when viewed from the rotation axis.   The magnetic refrigeration apparatus according to claim 1, wherein an opposing distance between the magnetic pole surface and the magnetic working body is asymptotically reduced from the circumferential center of the magnetic pole surface toward an end. The rotor further includes a magnetic flux control unit,
The magnetic refrigeration apparatus according to any one of claims 1 to 3, wherein the magnetic flux control unit is located outside the magnetic pole surface with respect to the rotation axis and has a magnetic body.   The magnetic refrigeration apparatus according to claim 4, wherein a thickness of the magnetic flux control unit at the center in the circumferential direction is greater than a thickness of the magnetic flux control unit at an end in the circumferential direction.   The magnetic refrigeration apparatus according to claim 4, wherein the thickness of the magnetic flux control unit is gradually reduced from the center in the circumferential direction toward the end.

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