Magnetic refrigeration unit and refrigeration device

Abstract

Two first rotating bodies (21) are disposed spaced apart in the axial direction of a rotating shaft (16). Second rotating bodies (22) are disposed between the two first rotating bodies (21). A first magnetic working substance (13) is disposed between the first rotating bodies (21) and the second rotating bodies (22). The first rotating bodies (21) are provided with a first magnet (31). The second rotating bodies (22) are provided with a second magnet (32). The magnetomotive force F1 of the first magnet (31) and the magnetomotive force F2 of the second magnet (32) satisfy the condition F1 < F2 < 2×F1.

Description

Magnetic refrigeration unit and refrigeration device

[0001] The present disclosure relates to a magnetic refrigeration unit and a refrigeration device.

[0002] Patent document 1 discloses a rotating magnetic field generating device that includes a disk with multiple magnets arranged around its circumference, a magnetic working material arranged in a magnetic field interaction space formed by stacking the disks at intervals so that the multiple magnets face each other, and a drive mechanism that rotates a rotating axis (shaft) to which the disk is fixed.

[0003] International Publication No. 2022 / 190586

[0004] However, when three or more magnets are arranged in the axial direction of the rotation shaft and a magnetic field is applied to a magnetic working material arranged between the magnets, if magnets with the same magnetomotive force are used, the amount of magnets will be excessive compared to the applied magnetic field strength required by the magnetic working material, resulting in a problem of increased costs.

[0005] An object of the present disclosure is to make it possible to apply an appropriate magnetic field to a magnetic working material using the minimum necessary amount of magnets.

[0006] A first aspect of the present disclosure is a rotor including a rotor shaft (16), two first rotors (21) spaced apart in the axial direction of the rotor shaft (16) and rotating together with the rotor shaft (16), a second rotor (22) disposed between the two first rotors (21) and rotating together with the rotor shaft (16), a first magnetic working material (13) disposed between the first rotors (21) and the second rotors (22), and a magnetic field generated by ... a first magnet (31) that faces the rotating shaft (16) in the axial direction and applies a magnetic field to the first magnetic working material (13); and a second magnet (32) that is provided on the second rotating body (22) and faces the rotating shaft (16) in the axial direction and applies a magnetic field to the first magnetic working material (13), wherein a magnetomotive force F1 of the first magnet (31) and a magnetomotive force F2 of the second magnet (32) satisfy a condition that F1<F2<2×F1.

[0007] In the first aspect, by appropriately setting the magnetomotive force of the first magnet (31) and the magnetomotive force of the second magnet (32), an appropriate magnetic field can be applied to the first magnetic working material (13) with the minimum necessary amount of magnets, thereby reducing the costs of the first magnet (31) and the second magnet (32).

[0008] A second aspect of the present disclosure is the magnetic refrigeration unit of the first aspect, wherein two or more second rotating bodies (22) are provided at intervals in the axial direction of the rotating shaft (16), and a second magnetic working material (14) is disposed between the two second rotating bodies (22).

[0009] In the second embodiment, a plurality of second rotors (22) are provided, so that a magnetic field can be applied to the second magnetic working material (14).

[0010] In a third aspect of the present disclosure, in the magnetic refrigeration unit of the first or second aspect, the first magnet (31) and the second magnet (32) are made of materials having the same coercive force, and a thickness t1 of the first magnet (31) and a thickness t2 of the second magnet (32) satisfy the condition t1<t2<2×t1.

[0011] In the third aspect, the magnetomotive forces of the first magnet (31) and the second magnet (32) can be changed by appropriately setting the thickness of the first magnet (31) and the thickness of the second magnet (32).

[0012] A fourth aspect of the present disclosure is a magnetic refrigeration unit according to the first or second aspect, wherein the first magnet (31) and the second magnet (32) are composed of electromagnets (50) that generate a magnetomotive force when current is passed through a winding (40), and the first magnet (31) and the second magnet (32) differ in at least one of the number of turns of the winding (40) and the value of the current passed therethrough.

[0013] In the fourth aspect, the magnetomotive force of the first magnet (31) and the second magnet (32) can be changed by appropriately setting at least one of the number of turns of the windings (40) of the first magnet (31) and the second magnet (32) and the value of the current passed therethrough.

[0014] A fifth aspect of the present disclosure is a refrigeration system including a magnetic refrigeration unit (10) according to any one of the first to fourth aspects and a heat medium circuit (2) exchanging heat with the magnetic refrigeration unit (10).

[0015] In the fifth aspect, a refrigeration system can be provided, which includes a magnetic refrigeration unit (10) and a heat medium circuit (2).

[0016] FIG. 1 is a piping system diagram of a refrigeration apparatus according to the first embodiment. FIG. 2 is a diagram showing the configuration of a magnetic refrigeration unit. FIG. 3 is a diagram showing the arrangement of magnets in a first comparative example. FIG. 4 is a diagram showing a magnetic resistance circuit. FIG. 5 is a diagram showing the arrangement of magnets in a second comparative example. FIG. 6 is a diagram showing a magnetic resistance circuit. FIG. 7 is a diagram showing the arrangement of magnets in the first embodiment. FIG. 8 is a diagram showing a magnetic resistance circuit. FIG. 9 is a diagram showing the flow of magnetic flux in a modified example of the first embodiment. FIG. 10 is a diagram showing the configuration of a magnetic refrigeration unit according to the second embodiment.

[0017] First Embodiment As shown in Fig. 1, a refrigeration system (1) includes a heat medium circuit (2). The refrigeration system (1) is applied to, for example, an air conditioner. The heat medium circuit (2) is filled with a heat medium. The heat medium includes, for example, a refrigerant, water, brine, etc.

[0018] The refrigeration system (1) includes a low-temperature side heat exchanger (3), a high-temperature side heat exchanger (4), a pump (5), and a magnetic refrigeration unit (10). The magnetic refrigeration unit (10) adjusts the temperature of a heat medium by utilizing the magnetocaloric effect.

[0019] The heat medium circuit (2) is formed in a closed loop and includes a pump (5), a low-temperature side heat exchanger (3), a magnetic refrigeration unit (10), and a high-temperature side heat exchanger (4) connected in this order.

[0020] The heat medium circuit (2) includes a low-temperature side flow path (2a) and a high-temperature side flow path (2b). The low-temperature side flow path (2a) connects the temperature control flow path (10a) of the magnetic refrigeration unit (10) to a first port (6a) of the pump (5). The high-temperature side flow path (2b) connects the temperature control flow path (10a) of the magnetic refrigeration unit (10) to a second port (6b) of the pump (5).

[0021] <Low-temperature side heat exchanger and high-temperature side heat exchanger> The low-temperature side heat exchanger (3) exchanges heat between the heat medium cooled in the magnetic refrigeration unit (10) and a predetermined object to be cooled (e.g., secondary refrigerant, air, etc.). The high-temperature side heat exchanger (4) exchanges heat between the heat medium heated in the magnetic refrigeration unit (10) and a predetermined object to be heated (e.g., secondary refrigerant, air, etc.).

[0022] <Pump> The pump (5) alternately performs a first operation and a second operation. In the first operation, the heat medium in the heat medium circuit (2) is transported leftward in FIG. 1. In the second operation, the heat medium in the heat medium circuit (2) is transported rightward in FIG. 1. The pump (5) constitutes a transport mechanism that causes the heat medium in the heat medium circuit (2) to flow reciprocally.

[0023] The pump (5) is a reciprocating piston pump and includes a pump case (6) and a piston (7).

[0024] The piston (7) is arranged inside the pump case (6) so as to be able to move back and forth. The piston (7) divides the interior of the pump case (6) into a first chamber (S1) and a second chamber (S2). The pump case (6) is formed with a first port (6a) and a second port (6b). The first port (6a) communicates with the first chamber (S1). The first port (6a) is connected to the low-temperature side flow path (2a). The second port (6b) communicates with the second chamber (S2). The second port (6b) is connected to the high-temperature side flow path (2b). The piston (7) is driven by a drive mechanism (not shown).

[0025] In the first operation, the piston (7) moves toward the first port (6a). In the first operation, the volume of the first chamber (S1) decreases and the volume of the second chamber (S2) increases. As a result, the heat transfer medium in the first chamber (S1) is discharged into the low-temperature side flow path (2a) through the first port (6a). At the same time, the heat transfer medium in the high-temperature side flow path (2b) is sucked into the second chamber (S2) through the second port (6b).

[0026] In the second operation, the piston (7) moves toward the second port (6b). In the second operation, the volume of the second chamber (S2) decreases and the volume of the first chamber (S1) increases. As a result, the heat transfer medium in the second chamber (S2) is discharged into the high-temperature side flow path (2b) through the second port (6b). At the same time, the heat transfer medium in the low-temperature side flow path (2a) is sucked into the first chamber (S1) through the first port (6a).

[0027] <Controller> The refrigeration system (1) includes a controller (8). The controller (8) controls the operation of the pump (5) and the magnetic refrigeration unit (10) in response to a predetermined operation command. The controller (8) is configured using a microcomputer and a memory device (specifically, a semiconductor memory) that stores software for operating the microcomputer.

[0028] <Magnetic Refrigeration Unit> As shown in FIG. 2, the magnetic refrigeration unit (10) includes a magnetic working material (11), a magnetic field application unit (12), and a rotation mechanism (15).

[0029] The magnetic working material (11) generates heat when a magnetic field is applied. The magnetic working material (11) absorbs heat when the magnetic field is removed. The magnetic working material (11) also generates heat when the applied magnetic field becomes stronger. The magnetic working material (11) also absorbs heat when the applied magnetic field becomes weaker. A plurality of magnetic working materials (11) are arranged at intervals in the circumferential direction of the rotating shaft (16).

[0030] A pipe (35) is connected to the magnetic working material (11). The pipe (35) constitutes a low-temperature side flow path (2a) and a high-temperature side flow path (2b) of the heat medium circuit (2) (see FIG. 1). A heat exchange medium that exchanges heat with the magnetic working material (11) flows through the pipe (35). The pipe (35) is connected to the magnetic working material (11) at a radially outer side of the rotating shaft (16).

[0031] The material of the magnetic working material (11) is, for example, Gd5 (Ge 0.5 Si 0.5 ) 4, La(Fe 1-x Si x ) 13 , La(Fe 1-x Co x Siy ) 13 , La(Fe 1-x Si x ) 13 H y , Mn(As 0.9 Sb 0.1 ) etc. can be used.

[0032] The rotation mechanism (15) has a rotation shaft (16) and a motor (17). The rotation shaft (16) is connected to the motor (17). The motor (17) rotates the rotation shaft (16). The magnetic field application unit (12) is connected to the rotation shaft (16).

[0033] The magnetic field application unit (12) has a first rotor (21) and a second rotor (22). Two first rotors (21) are arranged at an interval in the axial direction of the rotation shaft (16). The first rotors (21) rotate around the axis of the rotation shaft (16) in conjunction with the rotation of the motor (17).

[0034] The second rotor (22) is disposed between the two first rotors (21). Two or more second rotors (22) are provided at intervals in the axial direction of the rotary shaft (16). In the example shown in FIG. 2 , two second rotors (22) are provided. The second rotors (22) rotate around the axis of the rotary shaft (16) in conjunction with the rotation of the motor (17).

[0035] The magnetic working material (11) includes a first magnetic working material (13) and a second magnetic working material (14). The first magnetic working material (13) is disposed between a first rotating body (21) and a second rotating body (22). The second magnetic working material (14) is disposed between two second rotating bodies (22).

[0036] The first magnetic working material (13) and the second magnetic working material (14) are made of the same material and have the same shape, but differ only in their arrangement relative to the first rotor (21) and the second rotor (22).

[0037] The first rotor (21) includes a first core (25) and a plurality of first magnets (31). The first core (25) is made of a magnetic material and is fixed to the rotary shaft (16).

[0038] The plurality of first magnets (31) are provided on a surface of the first core portion (25) facing the first magnetic working material (13). The plurality of first magnets (31) are arranged at intervals in the circumferential direction of the rotating shaft (16). The first magnets (31) are permanent magnets. The magnetization direction of the first magnets (31) is oriented in the axial direction of the rotating shaft (16). The first magnets (31) constitute the magnetic poles of the first rotating body (21).

[0039] The second rotor (22) has a support portion (26) and a plurality of second magnets (32). The support portion (26) is made of a non-magnetic material. The support portion (26) is fixed to the rotary shaft (16).

[0040] The plurality of second magnets (32) are arranged radially outward from the support portion (26). The second magnets (32) are arranged at intervals in the circumferential direction so as to face the first magnets (31). The second magnets (32) are arranged so as to face the second magnets (32) of the adjacent second rotating body (22). The second magnets (32) are made of permanent magnets. The magnetization direction of the second magnets (32) is oriented in the axial direction of the rotation shaft (16). The second magnets (32) constitute the magnetic poles of the second rotating body (22).

[0041] The first magnet (31) and the second magnet (32) may be made of a material such as an Nd-Fe-B based magnet or an SmCo based magnet.

[0042] Here, the axial distance between the first rotating body (21) and the second rotating body (22), i.e., the distance from the lower surface of the first magnet (31) of the first rotating body (21) to the upper surface of the second magnet (32) of the second rotating body (22) in Figure 2, is approximately equal to the distance between adjacent second rotating bodies (22), i.e., the distance from the lower surface of the second magnet (32) of the upper second rotating body (22) to the upper surface of the second magnet (32) of the lower second rotating body (22) in Figure 2.

[0043] The first rotor (21) and the second rotor (22) rotate relative to the first magnetic working material (13) and the second magnetic working material (14) in the circumferential direction, thereby applying a magnetic field toward the magnetic working material (11) facing the first magnet (31) of the first rotor (21) and the second magnet (32) of the second rotor (22).

[0044] In the first rotor (21) shown at the top in Fig. 2, magnetic flux flows from the first magnet (31) on the right side in Fig. 2 through the first core portion (25) toward the first magnet (31) on the left side in Fig. 2. The flow of magnetic flux is indicated by dashed arrows.

[0045] In the first rotor (21) on the lower side in FIG. 2, magnetic flux flows from the first magnet (31) on the left side in FIG. 2 through the first core portion (25) toward the first magnet (31) on the right side.

[0046] In the two second rotors (22), magnetic flux flows in the axial direction in the order of the first magnet (31) of the first rotor (21) to the second magnet (32), the second magnet (32) of the adjacent second rotor (22), and the first magnet (31) of the first rotor (21).

[0047] A magnetic flux flows in the axial direction through the magnetic working material (11) disposed between the first magnet (31) of the first rotor (21) and the second magnet (32) of the second rotor (22), causing the magnetic working material (11) to generate heat when a magnetic field is applied thereto.

[0048] Thereafter, the first rotor (21) and the second rotor (22) are rotated so that the first magnet (31) of the first rotor (21) and the second magnet (32) of the second rotor (22) face the adjacent magnetic working material (11) in the axial direction. As a result, the magnetic working material (11) to which the magnetic field was first applied absorbs heat when the magnetic field is removed. On the other hand, the adjacent magnetic working material (11) generates heat when the magnetic field is applied.

[0049] <Regarding the magnetomotive force of magnets> When three or more magnets are arranged in the axial direction of the rotating shaft (16) and a magnetic field is applied to the magnetic working material (11) arranged between the magnets, if magnets with the same magnetomotive force are used, there is a problem that the amount of magnets will be excessive compared to the applied magnetic field strength required by the magnetic working material (11), resulting in increased costs.

[0050] Therefore, in this embodiment, an appropriate magnetic field can be applied to the magnetic working material (11) using the minimum necessary amount of magnets.

[0051] Specifically, the first magnet (31) and the second magnet (32) are made of materials having the same coercive force, and are set so that the thickness t1 of the first magnet (31) and the thickness t2 of the second magnet (32) satisfy the condition t1<t2<2×t1.

[0052] This allows the magnetomotive force F1 of the first magnet (31) and the magnetomotive force F2 of the second magnet (32) to be set so as to satisfy the condition F1<F2<2×F1.

[0053] Hereinafter, a case will be considered in which only one stage of magnetic working material (11) is arranged between two first rotors (21), as shown in Comparative Example 1 in Fig. 3. Note that in Fig. 3, the rotating shaft (16) is omitted for clarity.

[0054] As shown in Fig. 3, the thickness of the first magnet (31) is denoted by t1. As shown in Fig. 4, the magnetomotive force of the first magnet (31) is denoted by F1, the magnetic resistance of the magnetic working material (11) is denoted by Ra, and the magnetic resistance of the first core portion (25) is denoted by Rc.

[0055] If the total magnetic resistance in the magnetic resistance circuit in Figure 4 is R1, then R1 = 2 x Ra + 2 x Rc. If the total magnetomotive force in the magnetic resistance circuit in Figure 4 is Fm, then Fm = 4 x F1. If the magnetic flux flowing through the magnetic resistance circuit is φ1, then φ1 = Fm / R1.

[0056] Next, in Comparative Example 2 shown in Fig. 5, a case will be considered in which magnetic working materials (11) are arranged in two tiers, one above the other, between two first rotors (21). In Fig. 5, for ease of understanding, the rotating shaft (16) and the support portion (26) of the second rotor (22) are omitted.

[0057] As shown in Figure 5, second magnets (32) are arranged between the upper and lower two tiers of magnetic working materials (11). The second magnets (32) include a second magnet (32) corresponding to the upper first magnet (31) in Figure 5 and a second magnet (32) corresponding to the lower first magnet (31) in Figure 5. In other words, two tiers of second magnets (32) are arranged between the upper and lower two tiers of magnetic working materials (11). Here, the thickness t1 of the second magnets (32) is set equal to the thickness t1 of the first magnets (31).

[0058] In the example shown in Fig. 6, a second magnet (32) surrounded by a dashed line in Fig. 6 is added to the magnetic resistance circuit of Comparative Example 1. The magnetomotive force of the second magnet (32) is the same as that of the first magnet (31), that is, magnetomotive force F1.

[0059] Next, in this embodiment, as shown in Fig. 7, only one stage of second magnets (32) is disposed between two stages of upper and lower magnetic working materials (11). As shown in Fig. 7, the thickness of the second magnets (32) is denoted by t2. As shown in Fig. 8, the magnetomotive force of the second magnets (32) is denoted by F2.

[0060] 8, the total magnetic resistance is R2, so R2 = 4 × Ra + 2 × Rc. Here, if the total magnetic resistance added to the magnetic resistance circuit of Comparative Example 1 is R'2, then R'2 = R2 - R1 = 2 × Ra. R'2 is smaller than R1 (R'2 < R1).

[0061] Furthermore, if the magnetomotive force added to the magnetic resistance circuit of Comparative Example 1 is F'm, then F'm = 2 x F2. If the magnetic flux flowing through the magnetic resistance circuit is φ2, then φ2 = F'm / R'2.

[0062] In order to maintain a constant magnetic flux in the magnetic resistance circuit of Comparative Example 1 in Fig. 4 and the magnetic resistance circuit in Fig. 8, it is necessary to satisfy φ1 = φ2, and Fm / R1 = F'm / R'2, which results in F'm = (R'2 / R1) x Fm.

[0063] Here, Fm=4×F1, F'm=2×F2, so F2=2×(R'2 / R1)×F1. Note that since R'2<R1, (R'2 / R1)<1.

[0064] From the above, it is possible to calculate the magnetomotive force of the magnet required to generate magnetic flux by taking into account the magnetic resistance added to the magnetic resistance circuit of Figure 8. Specifically, the magnetomotive force per magnet added to the magnetic resistance circuit of Figure 8 is set to satisfy the condition F1 < F2 < 2 × F1.

[0065] Here, the magnetomotive force of a magnet is determined by Hcj × t, where Hcj is the coercive force of the magnet and t is the thickness of the magnet. Therefore, when using magnets with the same coercive force, it is sufficient to set the thickness of the magnet so that the condition t1 < t2 < 2 × t1 is satisfied.

[0066] -Effects of embodiment 1- According to the features of this embodiment, by appropriately setting the magnetomotive force of the first magnet (31) and the magnetomotive force of the second magnet (32), it is possible to apply an appropriate magnetic field to the first magnetic working material (13) with the minimum necessary amount of magnets, thereby reducing the costs of the first magnet (31) and the second magnet (32).

[0067] According to the feature of this embodiment, a plurality of second rotors (22) are provided, so that a magnetic field can be applied to the second magnetic working material (14).

[0068] According to the feature of this embodiment, the magnetomotive forces of the first magnet (31) and the second magnet (32) can be changed by appropriately setting the thickness of the first magnet (31) and the thickness of the second magnet (32).

[0069] According to the features of the present embodiment, it is possible to provide a refrigeration system including a magnetic refrigeration unit (10) and a heat medium circuit (2).

[0070] <<Variation of First Embodiment>> In the first embodiment, the magnetic flux flowing through the first magnet (31), the magnetic working material (11), and the second magnet (32) on the right side in FIG. 2 is made to flow to the first magnet (31), the magnetic working material (11), and the second magnet (32) on the left side in FIG. 2 via the first core portion (25), but the present invention is not limited to this configuration.

[0071] For example, by constructing the entire support portion (26) or a part thereof from a magnetic material and magnetically connecting the two upper and lower first core portions (25) to form a magnetic path, as shown in FIG. 9, the magnetic flux flowing through the first magnet (31), magnetic working material (11), and second magnet (32) on the right side in FIG. 9 may flow in the axial direction of the rotation shaft (16) via the first core portion (25), and then flow again through the first magnet (31), magnetic working material (11), and second magnet (32) on the right side in FIG. 9.

[0072] Similarly, the magnetic flux flowing through the first magnet (31), the magnetic working material (11), and the second magnet (32) on the left side in Figure 9 may be made to flow in the axial direction of the rotating shaft (16) via the first core portion (25), and then flow again through the first magnet (31), the magnetic working material (11), and the second magnet (32) on the left side in Figure 9.

[0073] Second Embodiment Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals, and only the differences will be described.

[0074] 10, the magnetic field application unit (12) has a first rotor (21) and a second rotor (22). Two first rotors (21) are arranged at an interval in the axial direction of the rotation shaft (16).

[0075] The second rotor (22) is disposed between the two first rotors (21). Two or more second rotors (22) are provided at intervals in the axial direction of the rotation shaft (16). In the example shown in Fig. 10, two second rotors (22) are provided.

[0076] The magnetic working material (11) includes a first magnetic working material (13) and a second magnetic working material (14). The first magnetic working material (13) is disposed between a first rotating body (21) and a second rotating body (22). The second magnetic working material (14) is disposed between two second rotating bodies (22).

[0077] The first rotor (21) has a first core portion (25) and a plurality of first magnets (31). The first magnets (31) are formed by electromagnets (50). Specifically, the first core portion (25) is formed of a magnetic material. A portion of the first core portion (25) protrudes toward the first magnetic working material (13). A winding (40) is wound around the protruding portion of the first core portion (25). The electromagnet (50) generates a magnetomotive force when current is applied to the winding (40).

[0078] The second rotor (22) has a support portion (26), a second core portion (27), and a plurality of second magnets (32). The support portion (26) is made of a non-magnetic material. The second core portion (27) is disposed radially outward of the support portion (26).

[0079] The second magnet (32) is formed by an electromagnet (50). The second core portion (27) is formed by a magnetic material. A winding (40) is wound around a part of the second core portion (27). The electromagnet (50) generates a magnetomotive force when a current is applied to the winding (40).

[0080] An electric wire (42) is connected to the winding (40). The electric wire (42) is routed along the rotating shaft (16). For example, the inside of the rotating shaft (16) may be hollow, and the electric wire (42) may be routed in the hollow portion of the rotating shaft (16).

[0081] A slip ring (45) is provided on the end of the rotating shaft (16) opposite to the motor (17). The slip ring (45) has a ring portion (46) and a brush portion (47). The ring portion (46) is disposed concentrically with the rotating shaft (16) at the end of the rotating shaft (16). An electric wire (42) is connected to the ring portion (46).

[0082] The brush portion (47) is electrically connected to the ring portion (46). The brush portion (47) is connected to the power source (41). The brush portion (47) is in contact with the ring portion (46) during rotation of the rotating shaft (16). As a result, current supplied from the power source (41) flows through the brush portion (47), the ring portion (46), and the electric wire (42) toward the winding (40). When current is applied to the winding (40), a magnetomotive force is generated in the electromagnet (50).

[0083] In this embodiment, the first magnet (31) and the second magnet (32) are different from each other in at least one of the number of turns of the winding (40) and the value of the current passed therethrough. Specifically, the magnetomotive force of the electromagnet (50) is determined by N×I, where N is the number of turns of the electric wire (42) and I is the value of the current passed therethrough. Here, the number of turns of the winding (40) of the first magnet (31) is N1, and the number of turns of the winding (40) of the second magnet (32) is N2.

[0084] 10, the number of turns N2 of the winding (40) of the second magnet (32) is greater than the number of turns N1 of the winding (40) of the first magnet (31) (N2>N1), and therefore the magnetomotive force of the second magnet (32) is greater than the magnetomotive force of the first magnet (31).

[0085] Here, when the value of the current flowing through the winding (40) is constant, the number of turns of the winding (40) can be set to satisfy the condition N1 < N2 < 2 × N1, thereby allowing the magnetomotive force F1 of the first magnet (31) and the magnetomotive force F2 of the second magnet (32) to be set to satisfy the condition F1 < F2 < 2 × F1.

[0086] Alternatively, the number of turns of the winding (40) may be the same, and the value of the current passed through the second magnet (32) may be greater than the value of the current passed through the first magnet (31).

[0087] -Effects of embodiment 2- According to the features of this embodiment, the magnetomotive force of the first magnet (31) and the second magnet (32) can be changed by appropriately setting at least one of the number of turns of the windings (40) of the first magnet (31) and the second magnet (32) and the value of the current to be passed.

[0088] Other Embodiments The above-described embodiment may be configured as follows.

[0089] In the present embodiment, the first magnet (31) and the second magnet (32) are made of materials having the same coercive force, but the present invention is not limited to this.

[0090] Specifically, since the magnetomotive force of a magnet is determined by Hcj × t, when magnets with different holding powers are used, the design condition for the magnet thickness is not necessarily t1 < t2 < 2 × t1. In this case, the magnetomotive force F1 of the first magnet (31) and the magnetomotive force F2 of the second magnet (32) should be designed to satisfy the condition F1 < F2 < 2 × F1.

[0091] In this embodiment, the first magnet (31) and the second magnet (32) are each formed of a single magnet, but the present invention is not limited to this. For example, the first magnet (31) and the second magnet (32) may be formed by stacking a plurality of magnets. Here, as long as the magnets have the same thickness, two first magnets (31) and three second magnets (32) may be stacked. Furthermore, the first magnet (31) may be a single magnet, and the second magnet (32) may be formed by stacking two magnets that are thinner than the first magnet (31).

[0092] In this embodiment, the first magnet (31) and the second magnet (32) are all permanent magnets, and the first magnet (31) and the second magnet (32) are all electromagnets. However, the present invention is not limited to this. For example, the first magnet (31) may be an electromagnet, and the second magnet (32) may be a permanent magnet.

[0093] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Furthermore, the terms "first," "second," "third," etc. in the specification and claims are used to distinguish between terms to which these terms are attached, and do not limit the number or order of those terms.

[0094] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful for magnetic refrigeration units and refrigeration devices.

[0095] REFRIGERATION DEVICE 2 HEAT TRANSPORT CIRCUIT 10 MAGNETIC REFRIGERATION UNIT 13 FIRST MAGNETIC WORKING SUBSTANCE 14 SECOND MAGNETIC WORKING SUBSTANCE 16 ROTATING SHAFT 21 FIRST ROTATING BODY 22 SECOND ROTATING BODY 31 FIRST MAGNET 32 SECOND MAGNET 40 WINDING 50 ELECTROMAGNET

Claims

1. A magnetic field generating device comprising: a rotating shaft (16); two first rotating bodies (21) spaced apart in the axial direction of the rotating shaft (16) and rotating together with the rotating shaft (16); a second rotating body (22) disposed between the two first rotating bodies (21) and rotating together with the rotating shaft (16); a first magnetic working material (13) disposed between the first rotating body (21) and the second rotating body (22); a first magnet (31) provided on the first rotating body (21) and facing the axial direction of the rotating shaft (16) to apply a magnetic field to the first magnetic working material (13); and a second magnet (32) provided on the second rotating body (22) and facing the axial direction of the rotating shaft (16) to apply a magnetic field to the first magnetic working material (13), A magnetic refrigeration unit, wherein a magnetomotive force F1 of the first magnet (31) and a magnetomotive force F2 of the second magnet (32) satisfy a condition of F1<F2<2×F1.

2. The magnetic refrigeration unit according to claim 1, wherein two or more second rotors (22) are provided at intervals in the axial direction of the rotary shaft (16), and a second magnetic working material (14) is disposed between the two second rotors (22).

3. A magnetic refrigeration unit according to claim 1 or 2, wherein the first magnet (31) and the second magnet (32) are made of materials having the same coercive force, and the thickness t1 of the first magnet (31) and the thickness t2 of the second magnet (32) satisfy the condition t1<t2<2×t1.

4. A magnetic refrigeration unit according to claim 1 or 2, wherein the first magnet (31) and the second magnet (32) are formed by electromagnets (50) that generate magnetomotive force when current is passed through a winding (40), and the first magnet (31) and the second magnet (32) differ in at least one of the number of turns of the winding (40) and the value of the current passed therethrough.

5. A refrigeration system comprising: a magnetic refrigeration unit (10) according to any one of claims 1 to 4; and a heat medium circuit (2) for exchanging heat with the magnetic refrigeration unit (10).

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