Patent Publication Number: US-2019170408-A1

Title: Magnetocaloric cycle device and element bed for the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is based on and claims the benefit of priority of Japanese Patent Application No. 2017-233625, filed on Dec. 5, 2017, the disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The disclosure in this specification relates to a magnetocaloric cycle device and an element bed for the same. 
     BACKGROUND ART 
     Patent Literature JP2008-51410A discloses a magnetocaloric cycle device and an element bed for the same. The so-called element bed includes a magnetocaloric effect element and a container. The container contains a magnetocaloric effect element. The container allows a magnetic field to be applied to the magnetocaloric effect element, and allows a heat transport medium to flow so as to perform a heat exchange with the magnetocaloric effect element. 
     SUMMARY 
     In the prior art, material and/or shape of the container is limited in order to allow application of the magnetic field to the magnetocaloric effect element. Conversely, magnetically desirable containers may cause mechanical strength deficiencies. When the container receives the pressure of the heat transport medium, the pressure resistance of the container may be impaired. Also, additionally or alternatively, it is desirable that containers have fewer losses such as magnetic losses, thermal losses, losses associated with eddy currents, and the like. Further improvement is required on the magnetocaloric cycle device and its element bed in view of the above described difficulties and/or not mentioned other difficulties. 
     It is a disclosed one object to provide a magnetocaloric cycle device and an element bed which are provided with containers advantageous from a magnetic point of view and from a mechanical strength point of view. 
     It is another disclosed object to provide a magnetocaloric cycle device and an element bed capable of suppressing loss caused by a container. 
     An element bed for a magnetocaloric cycle device disclosed herein comprises: a magnetocaloric effect element performing a magnetocaloric effect; and a container containing the magnetocaloric effect element, the container has a container member for providing walls of the container, and a reinforcing member disposed partially on the container member for reinforcing the container member. 
     According to the disclosed element bed for a magnetocaloric cycle device, the container of the element bed can be reinforced. By reinforcing the container from the viewpoint of mechanical strength, it is possible to improve the container from a magnetic viewpoint. As a result, it is possible to provide the container advantageous from the viewpoint of magnetic and mechanical strength. 
     A magnetocaloric cycle device disclosed herein comprises: the element bed described above; a magnetic field modulation device for modulating a magnetic field applied to the magnetocaloric effect device; and a heat transport device for generating a reciprocating flow of a heat transport medium that performs a heat exchange with the magnetocaloric effect device. 
     According to the disclosed magnetocaloric cycle device, a magnetocaloric cycle device having a container advantageous from a magnetic viewpoint and mechanical strength viewpoint is provided. 
     A magnetocaloric cycle device disclosed herein comprises: an element bed in which a reinforcing member is arranged at least on an overlapping wall; a magnetic field modulation device for modulating a magnetic field applied to the magnetocaloric effect device; and a heat transport device for generating a reciprocating flow of a heat transport medium that performs a heat exchange with the magnetocaloric effect device, further comprising: a bed group in which the plurality of element beds are arranged along a circumferential direction, wherein the direction of the magnetic flux is a radial direction, the overlapping wall is an outer wall and an inner wall facing in a radial direction, and a plurality of element beds are arranged so as to face side walls other than the overlapping wall. 
     According to the disclosed magnetocaloric cycle device, the reinforcing member is disposed on the overlapping wall that transmits the main magnetic flux acting on the magnetocaloric effect element. In a configuration in which a plurality of element beds are arranged along the circumferential direction, the outer wall and the inner wall face in the radial direction. Moreover, since the direction of the magnetic flux is a radial direction, the overlapping walls are the outer wall and the inner wall. Therefore, the reinforcing member can reinforce the outer wall and the inner wall which are required to have relatively high strength. 
     The disclosed aspects in this specification adopt different technical solutions from each other in order to achieve their respective objectives. Reference numerals in parentheses described in claims and this section exemplarily show corresponding relationships with parts of embodiments to be described later and are not intended to limit technical scopes. The objects, features, and advantages disclosed in this specification will become apparent by referring to following detailed descriptions and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram showing a device of a first embodiment; 
         FIG. 2  is a cross sectional view showing the device of the first embodiment; 
         FIG. 3  is a perspective view showing an element bed of the first embodiment; 
         FIG. 4  is a cross sectional view taken along a line IV-IV in  FIG. 3 ; 
         FIG. 5  is a cross sectional view taken along a line V-V in  FIG. 3 ; 
         FIG. 6  is a cross sectional view taken along a line VI-VI in  FIG. 3 ; 
         FIG. 7  is a perspective view showing an element bed of a second embodiment; 
         FIG. 8  is a perspective view showing an element bed of a the third embodiment; 
         FIG. 9  is a perspective view showing an element bed of a fourth embodiment; 
         FIG. 10  is a perspective view showing an element bed of a fifth embodiment; 
         FIG. 11  is a perspective view showing an element bed of a sixth embodiment; 
         FIG. 12  is a perspective view showing an element bed of a seventh embodiment; 
         FIG. 13  is a graph showing a temperature distribution of the element bed; 
         FIG. 14  is a cross sectional view showing a manufacturing method of an eighth embodiment; 
         FIG. 15  is a perspective view showing a manufacturing method of a ninth embodiment; 
         FIG. 16  is a perspective view showing an element bed of a tenth embodiment; 
         FIG. 17  is a cross sectional view taken along a line XVII-XVII in  FIG. 16 ; 
         FIG. 18  is a cross sectional view taken along a line XVIII-XVIII in  FIG. 16 ; 
         FIG. 19  is a cross sectional view taken along a line XIX-XIX in  FIG. 16 ; 
         FIG. 20  is a graph showing a temperature distribution of the element bed; 
         FIG. 21  is a perspective view showing a manufacturing method of an eleventh embodiment; 
         FIG. 22  is a cross sectional view showing a reinforcing member of a twelfth embodiment; 
         FIG. 23  is a cross sectional view showing a reinforcing member of a thirteenth embodiment; 
         FIG. 24  is a cross sectional view showing a reinforcing member of a fourteenth embodiment; and 
         FIG. 25  is a cross sectional view showing a reinforcing member of a fifteenth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a plurality of embodiments will be described with reference to the drawings. In some embodiments, parts that are functionally and/or structurally corresponding and/or associated are given the same reference numerals, or reference numerals with different hundred digit or more digits. For corresponding parts and/or associated parts, reference can be made to the description of other embodiments. 
     First Embodiment 
       FIG. 1  is a block diagram showing a magnetocaloric cycle device. The magnetocaloric cycle device provides a magnetocaloric effect type heat pump device  1 . The magnetocaloric effect type heat pump device  1  is called an MHP device  1 . MHP is an abbreviation of Magnetocaloric effect Heat Pump. The MHP device  1  is also called a magnetic heat pump device. The MHP device  1  provides a vehicle air conditioner. 
     In this specification the term “vehicle” is used in a broad sense. That is, the term “vehicle” includes a moving body having an occupant&#39;s compartment or a luggage compartment, for example, a motor vehicle, a ship, an airplane. In addition, the term “vehicle” includes a simulation equipment, an amusement equipment and the like. 
     In this specification the term “heat pump device” is used in a broad sense. That is, the term “heat pump device” includes both a device utilizing cold heat obtained by a heat pump device and a device utilizing heat obtained by a heat pump device. Devices that utilize a cold energy may also be referred to as refrigeration cycle devices. Hence, in this specification the term “heat pump device” is used as a concept encompassing a refrigeration cycle device. 
     The MHP device  1  includes a magnetocaloric effect element bed  2 . The magnetocaloric effect element bed  2  is called an element bed  2 . The element bed  2  has a container  3  and a magnetocaloric element  4 . The magnetocaloric element  4  is called an MCE element  4 . The MHP device  1  utilizes the magnetocaloric effect of the MCE element  4 . The container  3  partitions and forms a work chamber  3   a.  The container  3  accommodates the MCE element  4 . The MCE element  4  is accommodated in the work chamber  3   a.  The MCE element  4  is disposed between a high temperature end  11  which is an end region at one end of the work chamber  3   a  and a low temperature end  12  which is an end region at the other end of the working chamber  3   a.  The container  3  allows a magnetic field to be applied to the magnetocaloric effect element  4 , and allows a heat transport medium  5  to flow so as to perform a heat exchange with the magnetocaloric effect element  4 . The heat transport medium  5  can be provided by a fluid such as antifreeze, water, oil, gas or the like. Most of the container  3  is made of nonmagnetic material. 
     The MCE element  4  includes a magnetic work material having a magnetocaloric effect. MCE is an abbreviation of a Magneto-Caloric Effect. The NICE element  4  is disposed between the high temperature end  11  and the low temperature end  12 . The MCE element  4  generates a heat discharge and a heat absorption due to a change of strength of the external magnetic field. The container  3  and the MCE element  4  are arranged so as to form a flow path of the heat transport medium  5 . 
     The MCE element  4  has a plurality of element groups  4   n.  The illustrated number of element groups  4   n  is just an example. The MCE element  4  may have n groups of element groups  4   n.  The plurality of element groups  4   n  share a temperature gradient (temperature distribution) as a target value obtained during a steady operation. The temperature gradient produces the high-temperature end  11  and the low-temperature end  12 . The terms “high-temperature end  11 ” and “low-temperature end  12 ” refer to partial regions in the element bed  2 . The high-temperature end  11  and the low-temperature end  12  indicate a region outside the MCE element  2  in the longitudinal direction LD. In many cases, pipes, pumps, valve mechanisms and the like are arranged outside the high-temperature end  11  and the low-temperature end  12 . The temperature gradient is obtained as a result of the MHP apparatus  1  being operated for a long time. For example, the temperature gradient obtained during the steady operation provides high and low temperatures that can be used as the vehicle air conditioner. The plurality of element groups  4   n  are arranged along the longitudinal direction LD of the MCE element  4 , that is, along the flow direction of the heat transport medium  5 . The arrangement of the plurality of element groups  4   n  in such the MCE element  4  is called Cascade arrangement. 
     Materials constituting each of the plurality of element groups  4   n  have different Curie temperatures. The plurality of element groups  4   n  demonstrate a high magnetocaloric effect (ΔS(J/kgK)) in different temperature zones. The element group  4   n  close to the high-temperature end  11  has a material composition demonstrating a high magnetocaloric effect in a vicinity of the temperature appearing at the high-temperature end  11  in the steady operation state. The element group  4   n  close to a middle temperature portion has a material composition demonstrating a high magnetocaloric effect in a vicinity of the temperature appearing at the middle temperature portion in the steady operation state. The element group  4   n  close to the low-temperature end  12  has a material composition demonstrating a high magnetocaloric effect in a vicinity of the temperature appearing at the low-temperature end  12  in the steady operation state. 
     The MCE element  4  generates the heat discharge by applying the external magnetic field and generates the heat absorption by removal of the external magnetic field. The MCE element  4 , when the electron spin is aligned in the magnetic field direction by applying the external magnetic field, decreases magnetic entropy and demonstrates increasing of a temperature by discharging heat. Also, the MCE element  4 , when the electron spin becomes cluttered by removing the external magnetic field, increases the magnetic entropy and demonstrates decreasing of a temperature by absorbing heat. The NICE element  4  is made of a magnetic material that performs a high magnetocaloric effect in a normal temperature range. The magnetic material may be, for example, a gadolinium-based material. It may also be a mixture of manganese, iron, phosphorus and germanium. 
     The MHP device  1  includes a magnetic field modulation device  6  (MGFM) and a heat transport device  7  (FLDM). The magnetic field modulation device  6  and the heat transport device  7  make the MCE element  4  function as an AMR (Active Magnetic Refrigeration) cycle. The magnetic field modulation device  6  and the heat transport device  7  operate synchronously. 
     The magnetic field modulation device  6  applies the external magnetic field to the MCE element  4  and modulates the external magnetic field so as to increase or decrease an intensity of the external magnetic field. The external magnetic field is given along the thickness direction TD. A magnetic flux BS penetrating the container  3  along the thickness direction TD is illustrated. The magnetic field modulation device  6  periodically switches between an excitation state in which the MCE element  4  is placed in a strong magnetic field and a demagnetization state in which the MCE element  4  is placed in a weak magnetic field or in a zero magnetic field. The magnetic field modulation device  6  modulates the external magnetic field so as to periodically repeat the magnetization period in which the MCE element  4  is placed in a strong external magnetic field and the demagnetization period in which the MCE element  4  is placed in an external magnetic field weaker than the magnetization period. The magnetic field modulation device  6  can comprise a magnetic power source for generating the external magnetic field, for example a permanent magnet or an electromagnet. 
     The magnetic field modulation device  6  includes a magnetic member  6   a  including a permanent magnet. The magnetic member  6   a  is capable of applying the external magnetic field to the entire MCE element  4 . The total length of the magnetic member  6   a  is longer than the total length of the MCE element  4 . The magnetic member  6   a  is arranged so as to overlap with the MCE element  4 . The magnetic member  6   a  is arranged so as to overlap with the element bed  2 . The magnetic member  6   a  is disposed so as to overlap with the center area of the element bed  2  where the MCE element  4  is disposed. Further, the magnetic member  6   a  is arranged so as to overlap with the high-temperature end  11 . The magnetic member  6   a  also gives a change in the external magnetic field to the high-temperature end  11 . The magnetic member  6   a  is arranged so as to overlap the low-temperature end  12 . The magnetic member  6   a  also changes the external magnetic field to the low-temperature end  12 . In this manner, the magnetic field modulation device  6  also causes a change in the external magnetic field to be applied to the end region provided by the element bed. 
     The magnetic field modulation device  6  is provided by a mechanism which moves the element bed  2  and/or the permanent magnet and periodically and relatively changes a distance between the element bed  2  and the permanent magnet. The magnetic field modulation device  6  may include, for example, a rotation mechanism for rotating the permanent magnet with respect to the fixed element bed  2 . 
     The heat transport device  7  includes a fluid device for flowing the heat transport medium  5  for transporting the heat that the MCE element  4  discharges or absorbs. The heat transport device  7  is a device for flowing the heat transport medium  5  for heat exchange with the MCE element  4  along the MCE element  4 . The heat transport device  7  causes the heat transport medium  5  to flow so as to generate the high-temperature end and the low-temperature end in the MCE element  4 . The heat transport device  7  reciprocally flows the heat transport medium  5  synchronously with a change in the external magnetic field by the magnetic field modulation device  6 , for example. The heat transport device  7  may include a pump for flowing the heat transport medium  5 . The heat transport device  7  may comprise a plurality of passages for controlling the flow of the heat transport medium  5  and a valve mechanism. 
     The MHP device  1  has an air conditioner  8  (HVAC) for providing a vehicle air conditioner. The air conditioner  8  is also referred to as a unit for heating, ventilation, and air conditioning. The air conditioner  8  utilizes the high temperature obtained at the high-temperature end  11  and/or the low temperature obtained at the low-temperature end  12 . The high temperature and/or the low temperature may be took away from the MCE element  4  or take away from the heat transport medium  5 . 
     In  FIG. 2 , the MHP device  1  has the plurality of element beds  2 . The plurality of element beds  2  provide a plurality of element bed groups  2   a.  The plurality of element beds  2  belong to one element bed group  2   a.  The plurality of element beds  2  are arranged between the magnetic members  6   a  and  6   a  which are rotated by a power source. In the illustrated example, the MHP apparatus  1  has four element bed groups  2   a.  One element bed group  2   a  has three element beds  2 . The plurality of element beds  2  belonging to one element bed group  2   a  are simultaneously supplied with the heat transport medium  5  in the same flow direction. The plurality of element beds  2  belonging to one element bed group  2   a  are placed in the magnetization period or demagnetization period almost at the same time. The shape of the container  3  is shown slightly exaggerated. The container  3  is a cylindrical shape. The container  3  has a cross-sectional shape which can be referred to as a square tube or a cylinder. The cross-sectional shape of the container  3  may also be called a fan shape. 
     The container  3  has walls overlapping with the MCE element  4  with respect to the direction of the magnetic flux BS supplied to the MCE element  4 , i.e., walls overlapping the MCE element  4  in the thickness direction TD. This wall is called an overlapping wall. The overlapping wall extends orthogonally to the direction of the magnetic flux BS. The overlapping wall spreads to face in the radial direction. The overlapping walls face radially inward and radially outward of the container  3 . The container  3  has side walls other than the overlapping walls. The side walls face both circumferential sides of the container  3 . 
     Since many magnetic fluxes BS making an interlinkage with the MCE element  4  pass through the overlapping walls, the overlapping walls are largely related to the magnetic loss. The thinner the overlapping wall, the higher the strength of the effective magnetic flux BS. A part of the magnetic flux BS may pass through the side wall and make the interlinkage with the MCE element  4 . However, the magnetic flux BS which makes the interlinkage with the MCE element  4  and passes through the side wall is still small. For this reason, the side wall has a relatively small involvement in magnetic loss. From such a viewpoint, the overlapping wall is required to have a structure satisfying the strength required for the container  3  by a thin thickness. 
     In  FIG. 3 , the element bed  2  is somewhat schematically drawn. The thickness direction TD corresponds to the radial direction, and the width direction WD corresponds to the circumferential direction. The longitudinal direction LD is also the flow direction of the heat transport medium  5 . The element bed  2  has the container  3  and the MCE element  4 . The container  3  has a cylindrical shape extending along the longitudinal direction LD. The container  3  has a container member  31  and at least one reinforcing member  32 . The container  3  has a plurality of reinforcing members  32   a,    32   b,    32   c  and  32   d.    
     The MCE element  4  is provided by a plurality of particles  4   a.  The particle  4   a  may be called a grain. The plurality of particles  4   a  are filled in the container  3 . The plurality of particles  4   a  provides a flow path for the heat transport medium  5  therebetween. The cross-sectional area A 4  provided by the MCE element  4  is a part of the cross-sectional area A 3  provided by the container  3 . The MCE element  4  is arranged substantially uniformly in its installation region. As a result, the MCE element  4  and the flow path are distributed almost evenly. The flow path cross-sectional area A 4  is the sum of a plurality of dispersed flow paths in a cross section perpendicular to the longitudinal direction LD. The distributed arrangement of the flow paths provides good heat exchange between the MCE element  4  and the heat transport medium  5 . The MCE element  4  can be provided in various shapes such as a plate shape and a block shape forming a plurality of micro channels for flowing the heat transport medium  5 . 
     The container member  31  is made of a nonmagnetic material. The container member  31  has airtightness for holding the heat transport medium  5  without leaking. The container member  31  provides pressure resistance to withstand a pressure of the heat transport medium  5 . The container member  31  is made of a nonmagnetic material. 
     The reinforcing member  32  is partially provided in the container member  31 . The reinforcing member  32  reinforces the strength of the wall provided by the container member  31 . Therefore, in this embodiment, the pressure resistance of the container  3  is provided by the container member  31  and the reinforcing member  32 . 
     The reinforcing member  32  has a mechanical strength per unit volume which is larger than that of the container member  31 . In particular, the longitudinal elastic modulus of the reinforcing member  32  in the thickness direction TD is higher than the longitudinal elastic modulus of the container member  31 . As a result, the longitudinal elastic modulus of the container  3  is also high. The reinforcing member  32  may be provided by a metal. The reinforcing member  32  may be provided by a nonmagnetic metal such as aluminum, nonmagnetic stainless steel, titan or carbon. The reinforcing member  32  may be desirably provided by a material that has a low electric resistivity. In this case, it is expected to reduce a heat generation due to an eddy current loss. The reinforcing member  32  may be provided by a conductive material. The reinforcing member  32  may be provided by a magnetic material. The reinforcing member  32  may be provided by a magnetic metal such as iron, magnetic steel sheet, or magnetic stainless steel. In this embodiment, the reinforcing member  32  is made of iron. 
     The material of the container member  31  has a predetermined thermal conductivity. The thermal conductivity of the material of the container member  31  is lower than a thermal conductivity of a material of the reinforcing member  32 . Since the container member  31  provides most of the container  3 , it contributes to a low thermal conductivity of the container  3  itself. The container member  31  contributes to suppressing heat transfer between the high-temperature end  11  and the low-temperature end  12 . A resistivity of the container member  31  is higher than a resistivity of the reinforcing member  32 . Again, since the container member  31  provides most of the container  3 , it contributes to increasing the resistivity of the container  3  itself. As a result, the container  3  provides a high longitudinal modulus, a low thermal conductivity and a high electrical resistivity. With the characteristics of the material forming the container  3 , it is possible to achieve pressure resistance required for the container  3 , suppress loss due to heat conduction, and reduce loss due to eddy current. 
     The material of the container member  31  has a predetermined thermal conductivity. The thermal conductivity of the material of the container member  31  is lower than the thermal conductivity of the material of the reinforcing member  32 . The reinforcing member  32  promotes heat transfer between the high-temperature end  11  and the low-temperature end  12 . However, in the cross section perpendicular to the longitudinal direction LD, a cross-sectional area provided by the reinforcing member  32  is smaller than a cross-sectional area provided by the container member  31 . Therefore, the heat transfer through the reinforcing member  32  is restricted within an allowable range. 
       FIG. 4  shows a cross section taken along a line IV-IV in  FIG. 3 .  FIG. 5  shows a cross section taken along a line V-V in  FIG. 3 .  FIG. 6  shows a cross section taken along a line VI-VI of  FIG. 3 . In  FIGS. 3 to 6 , a shape of the container  3  is illustrated in detail. 
     The container  3  has a width W 3 . The width W 3  is also the width of the container member  31 . The container member  31  is cylindrical. The container member  31  defines the outer shape of the container  3 . Here, the cross section of the container  3  is described as a square. The container  3  has an outer wall  31   a  and an inner wall  31   b  as overlapping walls. The container  3  has side walls  31   c  and  31   d.  The boundary between the overlapping walls and the side walls is illustrated by a dashed line. The width W 31   a  of the outer wall  31   a  and the inner wall  31   b  as the overlapping walls are smaller than the width W 3 . Since the container  3  has a multi-sided or polygonal cylindrical shape, the corner portion belongs to the side wall. 
     The reinforcing member  32  extends along the longitudinal direction LD. A length Lrf of the reinforcing member  32  is equal to a length Lbed of the container  3 . The reinforcing member  32  is partially disposed on the container  3 . The reinforcing member  32  is partially disposed in the container member  31 . The reinforcing member  32  contributes to suppress a thickness of the container member  31 . 
     Each of the plurality of walls  31   a,    31   b,    31   c  and  31   d  provided by the container member  31  has a plurality of reinforcing members  32   a,    32   b,    32   c  and  32   d,  respectively. The outer wall  31   a  is reinforced by the reinforcing member  32   a.  The inner wall  31   b  is reinforced by the reinforcing member  32   b.  The side wall  31   c  is reinforced by the reinforcing member  32   c.  The side wall  31   d  is reinforced by the reinforcing member  32   d.  The reinforcing member  32  is arranged so as to extend along the center portion of the corresponding wall. For example, the reinforcing member  31   a  is disposed at the center of the width W 31   a  of the outer wall  31   a.  The reinforcing member  32   a  reduces the width of the wall provided only by the container member  31 . Specifically, the wall provided only by the container member  31  has a width W 31   a / 2 . 
     The reinforcing member  32  suppresses a width of a beam of the wall provided by the container member  31 . For example, the outer wall  31   a  receives an inner pressure in the working chamber  3   a  at the width W 31   a.  If the reinforcing member  32   a  is absence, the outer wall  31   a  may be curved over the length of the width W 31   a.  However, by disposing the reinforcing member  32   a,  the outer wall  31   a  is deformed over the width W 31   a / 2 . As a result, a deformation amount of the wall, i.e., a deformation amount of the container  3  is suppressed. 
     The reinforcing member  32  is arranged at regular intervals in a cross section perpendicular to the longitudinal direction LD of the container  3 . There is a wall of the container member  31  with a surface length Drf between the two adjacent reinforcing members  32  in a cross section perpendicular to the longitudinal direction LD. The arrangement of the plurality of reinforcing members  32   a,    32   b,    32   c  and  32   d  may not be exactly equally spaced. The plurality of reinforcing members  32   a,    32   b,    32   c  and  32   d  may be distributed so as to reinforce the container member  31 . It is preferable that the reinforcing member  32  is provided at least on the outer wall  31   a  and/or the inner wall  31   b.  Thereby, the outer wall  31   a  and/or the inner wall  31   b  are reinforced. The reinforcing member  32  may be provided on the side wall  31   c  and/or the side wall  31   d.  As a result, the pressure resistance of the entire container  3  is enhanced. 
     The reinforcing member  32  has a width Wrf of a single side and a height Trf of a long side in a cross section perpendicular to the longitudinal direction LD. The width Wrf is smaller than the height Trf (Wrf&lt;Trf). The height Trf is a direction along the magnetic flux BS. The width Wrf intersects the magnetic flux BS. In other words, the cross section of the reinforcing member  32  has a long side and a short side. The reinforcing member  32  is arranged so that the long side is parallel to the magnetic flux BS. The reinforcing member  32  can be said to have a vertically elongated cross section along the direction of the magnetic flux BS supplied to the MCE element  4 . The vertically elongated cross section suppresses an interlinkage between the magnetic flux BS and the reinforcing member  32  and suppresses a loss caused by the interlinkage. The reinforcing member  32  having a vertically elongated cross section suppresses, for example, a loss due to an eddy current. The elongated cross section effectively increases the strength of the container member  31  in the thickness direction TD. For example, the elongated cross section provides strength against the internal pressure of the working chamber  3   a.    
     The reinforcing member  32  is disposed on an outside of the wall of the container  3 . The reinforcing member  32   a  occupies an outer side in the radial direction of the outer wall  31   a.  The height Trf of the reinforcing member  32  occupies a part of the thickness T 3  of the outer wall  31   a.  The container member  31  has a thickness Tc as a cylindrical portion for partitioning the working chamber  3   a.  The cylindrical portion is formed by a continuous material to provide sealing properties. The cylindrical portion is continuous over an entire circumference and over an entire length. The thickness Tc of the cylindrical portion is larger than the height Trf of the reinforcing member  32   a.    
     In this embodiment, all of the outer wall  31   a,  the inner wall  31   b,  the side wall  31   c,  and the side wall  31   d  have the thickness T 3 . The thickness T 3  of these walls is a relatively thin thickness satisfying the pressure resistance required of the container  3  under reinforcement by the reinforcing member  32 . The side wall (the side wall  31   c  and the side wall  31   d ) may be formed thicker than the overlapping wall (the outer wall  31   a  and the inner wall  31   b ). 
     According to the embodiment described above, the container  3  has the container member  31  and the reinforcing member  32 . Thus, it is possible to select the material and shape of the container member  31  from a magnetic viewpoint. In addition, the reinforcing member  32  can satisfy the requirements from a mechanical strength viewpoint. Therefore, it is possible to provide the element bed  2  and the MHP device  1  having the container  3  which is advantageous from the magnetic viewpoint and the mechanical strength viewpoint. 
     In this embodiment, the reinforcing member  32  is arranged on the outer wall  31   a  and/or the inner wall  31   b  which are overlapping walls overlapping the MCE element  4  with respect to the magnetic flux BS. For this reason, it is possible to provide the container  3  with walls advantageous in the magnetic viewpoint and the mechanical strength viewpoint. 
     In this embodiment, the container member  31  made of the nonmagnetic material and the reinforcing member  32  made of the magnetic material are used. This provides high flexibility in material selection. 
     In this embodiment, the reinforcing member  32  has an elongated cross section. The elongated cross section suppresses an interlinkage with the magnetic flux BS. Therefore, a magnetic loss in the container  3  is suppressed. In this embodiment, a metal reinforcing member  32  is used. If the magnetic flux BS making the interlinkage with the metallic reinforcing member  32  changes, an eddy current loss occurs in the reinforcing member  32 . The elongated cross section suppresses eddy current loss, for example. 
     Returning to  FIG. 2 , the MHP device  1  has the bed group  2   a  in which a plurality of element beds  2  are arranged along the circumferential direction. The direction of the magnetic flux BS supplied to the MCE element  4 , in other words, the direction of the magnetic flux BS supplied by the magnetic field modulation device  6  is in the radial direction. The plurality of element beds  2  are arranged to face the side walls  31   c  and  31   d  other than the overlapping walls. The overlapping walls are the outer wall  31   a  and the inner wall  31   b  that face in the radial direction. In a configuration in which a plurality of element beds  2  are arranged along the circumferential direction as one element bed group  2   a,  the outer wall  31   a  and the inner wall  31   b  face in the radial direction. The reinforcing member  32  is disposed in an overlapping wall that transmits at least the main magnetic flux. In addition, since the direction of the magnetic flux BS is in the radial direction, the overlapping walls are the outer wall  31   a  and the inner wall  31   b.  Therefore, the reinforcing member  32  can reinforce the outer wall  31   a  and the inner wall  31   b  which are required to have relatively high strength. 
     Second Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, one reinforcing member is disposed on one wall. Alternatively, in this embodiment, a plurality of reinforcing members are arranged on one wall. 
       FIG. 7  shows an element bed  2  of this embodiment. Each of the plurality of walls  31   a,    31   b,    31   c  and  31   d  has a plurality of reinforcing members  32 . The representative outer wall  31   a  has additional reinforcing members  232   e,    232   f,    232   g  and  232   h  in addition to the central reinforcing member  32   a.  The plurality of reinforcing members  32   a,    232   e,    232   f,    232   g  and  232   h  provide density of the reinforcing members. The density is relatively high at a central region of a wall and is relatively low at both end regions of a wall. Therefore, the plurality of reinforcing members creates a density distribution along the width direction. The plurality of reinforcing members  32   a,    232   e,    232   f,    232   g  and  232   h  arranged on one wall  31   a  makes it possible to improve the strength of the wall  31   a.    
     Third Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the reinforcing members are arranged on all the walls. Alternatively, the reinforcing member may be disposed only on the overlapping wall. 
       FIG. 8  shows an element bed  2  of this embodiment. The outer wall  31   a  as an overlapping wall has a reinforcing member  32   a.  The inner wall  31   b  as an overlapping wall has a reinforcing member  32   b.  The side wall  31   c  does not have the reinforcing member  32 . The side wall  31   d  does not have the reinforcing member  32 . In this way, the reinforcing member  32  may be disposed only on the overlapping wall. 
     The outer wall  31   a  and the inner wall  31   b  have a thickness T 3   r.  The side wall  31   c  and the side wall  31   d  have a thickness T 3   c.  The thickness T 3   r  is smaller than the thickness T 3   c  (T 3   c &lt;T 3   r ). The outer wall  31   a  and the inner wall  31   b  provide required strength by the reinforcing members  32   a,    32   b.    
     According to this embodiment, a material easy to pass through the magnetic flux BS can be utilized for the overlapping wall. Moreover, since the overlapping wall is thinner than the side wall, it is easy to pass the magnetic flux BS. Furthermore, by arranging the reinforcing member  32  at least on the overlapping wall, the overlapping wall is reinforced. For this reason, it is possible to utilize a material with low mechanical strength for overlapping walls or to make the overlapping wall thin. As a result, design requirements can be satisfied both in terms of magnetic and mechanical strength. 
     Fourth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the reinforcing member is disposed so as to be exposed on the outer surface of the wall. Alternatively, the reinforcing member may be disposed in an embedded condition in the wall. 
       FIG. 9  shows an element bed  2  of this embodiment. The wall of the container member  31  has the reinforcing member  32  inside. The reinforcing member  32  is embedded in the wall of the container member  31 . The reinforcing member  32  is buried. In the illustrated example, the reinforcing member  32  is exposed at the end surface of the container  3 , but the reinforcing member  32  may be covered by the container member  31  also at the end surface. For example, at least one reinforcing member  432   a  is buried in the outer wall  31   a.  The outer wall  31   a  has a plurality of reinforcing members  432   a.  The reinforcing members may also be arranged in the other walls as well. 
     Fifth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the reinforcing member is disposed in the wall. Alternatively, the reinforcing member may be disposed so as to protrude from the outer surface of the wall. 
       FIG. 10  shows an element bed  2  of this embodiment. The wall of the container member  31  has the reinforcing member  32  on its outer surface. The reinforcing member  32  is adhered to the outer surface of the container member  31 . For example, at least one reinforcing member  532   a  is attached to the outer wall  31   a.  The reinforcing member  532   a  suppresses the deformation amount of the outer wall  31   a  by reinforcing the container member  31 . The reinforcing members may also be arranged in the other walls as well. In this embodiment as well, the overlapping wall is reinforced. 
     Sixth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the container  3  has a polygonal cylindrical shape. Alternatively, the container  3  may be a circular or an elliptical with no corners or planes. 
       FIG. 11  shows an element bed  2  of this embodiment. The container  3  is cylindrical. In the container  3 , a working chamber  3   a  is partitioned by an internal cavity of a circular cylinder. In the working chamber  3   a,  the MCE element  4  is accommodated. Even in the circular cylindrical container  3 , it is possible to determine overlapping walls overlapping the MCE element  4  with respect to the direction of the magnetic flux BS and side walls. The outer wall  631   a  positioned radially outside with respect to the MCE element  4  is a curved surface. The inner wall  631   b  positioned radially inside with respect to the MCE element  4  is a curved surface. The outer wall  631   a  and the inner wall  631   b  provide overlapping walls. Portions connecting the outer wall  631   a  and the inner wall  631   b  are referred to as a side wall  631   c  and a side wall  631   d.    
     Also in this embodiment, the reinforcing member  32  reinforces the wall provided by the container member  31 . The container  3  has a width W 3  with respect to the direction of the magnetic flux BS. The overlapping wall has a width W 31   a.  The reinforcing member  632   a  reinforces the outer wall  631   a  as an overlapping wall. The reinforcing member  632   b  reinforces the inner wall  631   b  as an overlapping wall. The reinforcing member  632   c  reinforces the side wall  631   c.  The reinforcing member  632   d  reinforces the side wall  631   d.    
     The shape of the container in this embodiment can be combined with other embodiments. For example, the thickness of the overlapping walls may be made thinner than the thickness of the side walls. In addition, the reinforcing member  32  may be provided only on the overlapping wall. Further, the overlapping wall may include a plurality of reinforcing members. 
     Seventh Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the reinforcing member  32  extends only along the longitudinal direction LD. Alternatively, the reinforcing member may extend in a circumferential direction of the container  3 . In addition, the reinforcing member  32  may extend with respect to both the longitudinal direction LD and the circumferential direction (both the thickness direction TD and the width direction WD), that is, may extend obliquely with respect to the longitudinal direction LD. Further, the reinforcing member  32  may have a plurality of reinforcing members spaced apart from each other in the longitudinal direction LD. 
       FIG. 12  shows an element bed  2  of this embodiment. The container  3  has a reinforcing member  32  extending obliquely with respect to the longitudinal direction LD on the wall provided by the container member  31 . The thermal conductivity of the material of the container member  31  is lower than the thermal conductivity of the material of the reinforcing member  32 . The container  3  has a plurality of reinforcing members  32  which elongated spirally along the longitudinal direction LD. The plurality of reinforcing members  32  arranged on one wall are not continuous along the longitudinal direction LD. However, the plurality of reinforcing members  32  are spaced apart from each other by a predetermined distance in the circumferential direction, and are arranged in parallel by a predetermined length. In other words, the plurality of reinforcing members  32  arranged on one wall are overlapped. A space between the two reinforcing members  32  is filled with the container member  31 . Such the plurality of non-continuous reinforcing members  32  suppress heat transfer along the longitudinal direction LD between the high-temperature end  11  and the low-temperature end  12  while increasing the strength of the container  3 . 
     Heat transfer through a plurality of reinforcing members  732   a  disposed on the outer wall  31   a  is described. The n-th reinforcing member  732   a (n) overlaps at least one end with another reinforcing member  732 (n+1) and/or another reinforcing member  732 (n−1). A length of an overlapping range is a length Lv. Between the plurality of reinforcing members  732   a,  the container member  31  or air is existed. Therefore, between the plurality of reinforcing members  732   a  is kept a high thermal resistance condition with respect to each other. As a result, heat transfer through one reinforcing member  732   a (n) is suppressed. 
       FIG. 13  is a schematic graph for explaining heat transfer. (A) shows a model of heat transfer in the previous embodiment. (B) shows a model of heat transfer in this embodiment. The horizontal axis represents the length. The vertical axis represents a temperature TH of the high-temperature end  11  and a temperature TL of the low-temperature end  12 . 
     In the preceding embodiment, the reinforcing member  32  is provided to extend between the high-temperature end  11  and the low-temperature end  12 . This causes heat transfer through the reinforcing member  32 . Heat transfer reduces the operation efficiency of the MHP device  1 . 
     In this embodiment, the n-th reinforcing member  732   a (n) provides only a part of the entire length of the element bed  2 . Moreover, the n-th reinforcing member  732   a (n) overlaps with the (n+1)-th reinforcing member  732   a (n+1) or the (n−1)-th reinforcing member  732   a (n−1) with respect to the longitudinal direction LD at least at one end. In this overlapping range, since the plurality of reinforcing members  732  are arranged on one wall, the wall can be reinforced. Moreover, the two overlapping reinforcing members  732  are separated each other. Therefore, heat transfer between the two reinforcing members  732  is suppressed. 
     In the drawing, the overlapping relationship with the n-th reinforcing member  732   a (n) is illustrated. In addition, a temperature gradient of the n-th reinforcing member  732   a (n) illustrated in (B) of  FIG. 13  is smaller than a temperature gradient illustrated in (A) of  FIG. 13  due to the high thermal conductivity of the reinforcing member  32 . Therefore, the reinforcing member  32  suppresses the temperature inclination in one of the plurality of Cascade-connected element groups. For example, the length of one element group may correspond to the length of one reinforcing member  32 . 
     According to this embodiment, heat transfer through the reinforcing member  32  can be suppressed even if the reinforcing member  32  is provided by a metal or the like having a high thermal conductivity. Moreover, since the plurality of reinforcing members  32  extend in the longitudinal direction LD while overlapping in the circumferential direction, partial strength insufficiency in the wall of the container  3  is suppressed. 
     Eighth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment provides one of manufacturing methods for the element bed  2  of the above embodiment. 
       FIG. 14  shows one step of the method for manufacturing the element bed  2  of this embodiment. An order of steps described in this embodiment can be interchanged. A method for manufacturing the element bed  2  includes a step of preparing a container  3 , a step of preparing an MCE element  4 , and a step of placing the MCE element  4  in the container  3 . 
     The step of preparing the container  3  includes a step of preparing a container member  31  which provides a main wall of the container  3 . The step of preparing the container member  31  is also a stage of preparing a cylindrical member. When the container member  31  is provided by resin or aluminum, the cylindrical member is manufactured by a molding technique called injection molding, die casting or the like. The step of preparing the container member  31  may include a step of preparing a shape for providing the reinforcing member  32 . This step includes a step of forming a groove for providing the reinforcing member  32  on the container member  31 . 
     The step of preparing the container  3  includes a step of preparing the reinforcing member  32 . The reinforcing member  32  is prepared as a rod-like member. The step of preparing the container  3  includes a step of attaching the reinforcing member  32  to the container member  31 . The step of preparing the container  3  includes a step of mounting the reinforcing member  32  in the groove of the container member  31  along the radial direction. The reinforcing member  32  is fixed to the container member  31  by fixing means such as press fitting, adhesion, caulking or the like. 
     Ninth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment provides one of manufacturing methods for the element bed  2  of the above embodiment. 
       FIG. 15  shows one step of the method for manufacturing the element bed  2  of this embodiment. This embodiment provides a step of mounting the reinforcing member  32  to the container member  31 . The step of preparing the container member  31  includes a step of forming a hole for providing the reinforcing member  32 . The reinforcing member  32  is inserted into the hole along the longitudinal direction LD. In addition, the reinforcing member  32  may be insert molded in the container member  31 . 
     Tenth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the above embodiment, the reinforcing member  32  extends at least along the longitudinal direction LD. Alternatively, the reinforcing member may extend only in a circumferential direction of the container  3 . 
       FIG. 16  shows an element bed  2  of this embodiment. The container  3  includes a cylindrical container member A 31 . The container member A 31  extends over the entire length of the container  3 . The container  3  has a plurality of reinforcing members A 32 . The reinforcing member A 32  extends along the outer side of the container member A 31 . The reinforcing member A 32  extends over the entire circumference of the container member A 31 . The reinforcing member A 32  is annular to surround the entire circumference of the container member A 31 . Therefore, a plurality of reinforcing members A 32  are arranged on the outer side of the container member A 31 . Predetermined intervals are provided between the plurality of reinforcing members A 32 . One reinforcing member A 32  has a length L 32  along the longitudinal direction LD. 
     The container  3  has a plurality of spacers A 33 . The plurality of spacers A 33  are arranged between the plurality of reinforcing members A 32 . As a result, the plurality of reinforcing members A 32  and the plurality of spacers A 33  are alternately arranged on the outer side of the container member A 31 . One reinforcing member A 32  has a length L 33  along the longitudinal direction LD. The length L 33  is smaller than the length L 32 . The spacer A 33  can be provided by the same material as the container member A 31 . The thermal conductivity of the material of the spacer A 33  is smaller than the thermal conductivity of the reinforcing member A 32 . Thereby, heat transfer between the high-temperature end  11  and the low-temperature end  12  is suppressed. 
       FIG. 17  shows a cross section taken along a line XVII-XVII in  FIG. 16 . The container member A 31  has a thickness Tsc. The spacer A 33  is an annular member having a thickness Tsp. The container member A 31  and the spacer A 33  provide the thickness T 3  of the container  3 . The thickness T 3  provides the pressure resistance required for the container  3  by the material of the container member A 31  and the material of the spacer A 33 . In this viewpoint, the spacer A 33  is also a reinforcing member for the container member A 31 . A part of the spacer A 33  reinforces an outer wall A 31   a  and an inner wall A 31   b.  In addition, a part of the spacer A 33  reinforces a side wall A 31   c  and a side wall A 31   d.    
       FIG. 18  shows a cross section taken along a line XVIII-XVIII in  FIG. 16 . The reinforcing member A 32  is an annular member having a thickness Trf. The container member A 31  and the reinforcing member A 32  provide the thickness T 3  of the container  3 . The thickness T 3  provides the pressure resistance required for the container  3  by the material of the container member A 31  and the material of the spacer A 33 . A part of the reinforcing member A 32  reinforces the outer wall A 31   a  and the inner wall A 31   b.  A part of the reinforcing member A 32  reinforces the side wall A 31   c  and the side wall A 31   d.    
       FIG. 19  shows a cross section taken along a line XIX-XIX of  FIG. 16 . Also in this embodiment, the reinforcing member A 32  reinforces the outer wall A 31   a  which is the overlapping wall and the inner wall A 31   b.  The spacer A 33  also reinforces the outer wall A 31   a  which is the overlapping wall and the inner wall A 31   b.  In this embodiment, the reinforcing member A 32  is dispersed only in the longitudinal direction LD, so that the container member A 31  is reinforced. The amount of deformation of the container member A 31  in the longitudinal direction LD is suppressed. 
       FIG. 20  shows a temperature distribution in  FIG. 19 . A thermal conductivity Tc 1  provided by the reinforcing member A 32  is larger than a thermal conductivity Tc 2  provided by the spacer A 33 . Therefore, a heat transfer occurring in the reinforcing member A 32  is larger than a heat movement occurring in the spacer A 33 . A curve of the temperature distribution TG shows the temperature gradient TG 1  in a range including the reinforcing member A 32 . The curve of the temperature distribution TG shows the temperature gradient TG 2  in a range including the spacer A 33 . The temperature gradient TG 2  is larger than the temperature gradient TG 1 . In other words, in the reinforcing member A 32 , the temperature difference with respect to the longitudinal direction LD tends to be small. On the other hand, the spacer A 33  acts so as to maintain the temperature difference. In this embodiment, since the length L 32  is shorter than the length L 33 , a heat transfer due to the plurality of reinforcing members A 32  is suppressed. On the other hand, since the length L 33  is longer than the length L 32 , the temperature difference is maintained by the plurality of spacers A 33 . 
     The plurality of reinforcing members A 32  and the plurality of spacers A 33  can be arranged so as to coincide with the pitch of the plurality of element groups  4   n.  For example, it is possible to dispose the reinforcing member A 32  at the central portion of one element group  4   n  and arrange the spacer A 33  over the adjacent element group  4   n.  In such an arrangement, the temperature difference in one element group  4   n  is suppressed by the reinforcing member A 32 . Therefore, it is possible to dispose a plurality of particles  4   a  dispersedly arranged in the longitudinal direction LD within a single element group  4   n  in a narrow temperature zone. In addition, the spacer A 33  disposed between the plurality of element groups  4   n  acts to maintain the temperature difference between the plurality of element groups  4   n.    
     Eleventh Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment provides one of manufacturing methods for the element bed  2  of the above embodiment. 
       FIG. 21  shows one step of the method for manufacturing the element bed  2  of this embodiment. A step of preparing the container  3  includes preparing an annular reinforcing member A 32  and an annular spacer A 33 , and preparing a cylindrical container member A 31 . Further, a preparing step of the container  3  includes a step of alternately putting a plurality of reinforcing members A 32  and a plurality of spacers A 33  on the container member A 31 . This step is also a step of inserting the container member A 31  along the longitudinal direction LD into the plurality of alternately arranged reinforcing members A 32  and the plurality of spacers A 33 . In addition, the reinforcing members A 32  may be insert-molded in a resin that provides the container member A 31  and the spacers A 33 . In addition, the reinforcing members A 32  and the spacers A 33  may be formed into an annular shape by winding these materials around the outer periphery of the container member A 31 . 
     Twelfth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. In the preceding embodiment, a reinforcing member  32 ,  732 , A  32  having a quadrilateral or quadrangular cross section is used. Alternatively, a reinforcing member having various cross-sectional shapes can be used. This embodiment employs a reinforcing member having a cross section whose major axis is inclined with respect to the direction of the magnetic flux BS. 
       FIG. 22  shows a cross section orthogonal to the longitudinal direction LD of the reinforcing member C 32 . The reinforcing member C 32  has a cross section which can be referred to as a quadrilateral shape or a quadrangular shape. It can be said that the cross section of the reinforcing member C 32  has a vertically long cross section. However, the major axis AXL defining the vertically long cross section is inclined by the inclination angle RD with respect to the direction of the magnetic flux BS, The inclination angle RD is set so as to suppress a projected length Lpr (projected area) in the direction of the magnetic flux BS. For example, since the maximum value of the projected length Lpr is determined according to an aspect ratio of the cross section of the reinforcing member C 32 , the inclination angle RD is set so as to make the projected length Lpr smaller than the maximum value. 
     Since the shorter the projected length Lpr, the smaller the projected area of the reinforcing member C 32 , the magnetic adverse effect due to the reinforcing member C 32  is suppressed. For example, when the reinforcing member C 32  is provided by a conductive material, a loss due to the eddy current is suppressed. In addition, in a case where the reinforcing member C 32  is provided by a material which generates heat by the interlinkage with the magnetic flux BS, a decrease in a temperature difference between the high-temperature end  11  and the low-temperature end  11  due to heat discharge is suppressed. Further, in a case where the reinforcing member C 32  is provided by a magnetic material, concentration of the magnetic flux on the reinforcing member C  32  can be suppressed. 
     Thirteenth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment employs a reinforcing member D 32  having a cross section which can be referred to as a triangle or a trilateral having a major axis AXL parallel to the direction of the magnetic flux BS. 
       FIG. 23  shows a cross section orthogonal to the longitudinal direction LD of the reinforcing member D 32 . The reinforcing member D 32  has a cross section like an isosceles triangle. The major axis AXL defining the elongated cross section is parallel to the direction of the magnetic flux BS. Also in this embodiment, the longitudinal axis AXL of the reinforcing member D 32  may be inclined with respect to the direction of the magnetic flux BS. 
     Fourteenth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment employs a reinforcing member E 32  having a cross section which can be referred to as an ellipse having a major axis AXL parallel to the direction of the magnetic flux BS. 
       FIG. 24  shows a cross section orthogonal to the longitudinal direction LD of the reinforcing member E 32 . The reinforcing member E 32  has a cross section like an ellipse. The major axis AXL defining the elongated cross section is parallel to the direction of the magnetic flux BS. Also in this embodiment, the longitudinal axis AXL of the reinforcing member E 32  may be inclined with respect to the direction of the magnetic flux BS. Further, the cross section of the reinforcing member E 32  can be provided by various cross-sectional shapes such as an oval shape, a semicircular shape, an arc shape surrounded by an arc and a string, and the like. 
     Fifteenth Embodiment 
     This embodiment is a modification in which the preceding embodiment is a base fundamental form. This embodiment employs a reinforcing member F 32  having a cross section which is called a circular shape. 
       FIG. 25  shows a cross section orthogonal to the longitudinal direction LD of the reinforcing member F 32 . The reinforcing member F 32  has a circular cross section. Also in this embodiment, the overlapping wall can be reinforced by the reinforcing member F 32 . As a result, restrictions in terms of mechanical strength are reduced, and instead, materials and/or shapes of overlapping walls can be set from a magnetic viewpoint. In addition, since the overlapping wall mainly passing the magnetic flux making the interlinkage with the MCE element  4  is reinforced, loss caused by the container  3  is suppressed. 
     Other Embodiments 
     The disclosure in this specification is not limited to the illustrated embodiment. The disclosure encompasses the illustrated embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the parts and/or combinations of elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure may have additional parts that may be added to the embodiment. The disclosure encompasses omissions of parts and/or elements of the embodiments. The disclosure encompasses replacement or combination of parts and/or elements between one embodiment and another. The disclosed technical scope is not limited to the description of the embodiment. Several technical scopes disclosed are indicated by descriptions in the claims and should be understood to include all modifications within the meaning and scope equivalent to the descriptions in the claims. 
     In the above embodiment, the rod-like reinforcing member  32  is utilized. Alternatively, it is possible to use reinforcing members having various shapes such as a net shape and a wave shape. 
     Also, the shape of one embodiment can be applied to other embodiments. For example, a configuration in which the overlapping wall is thinner than the side wall can be adopted in all the embodiments.