motor

Abstract

To obtain a motor that can improve the efficiency of cooling the heat-generating part in the shaft. [Solution] This motor comprises a shaft 1, a rotor 5 provided on the shaft 1, a stator 6 provided opposite the rotor 5, and a fan 7 provided on the shaft 1 offset in the axial direction from the rotor 5. The shaft 1 has a heat-generating section 101 on which the rotor 5 is provided, and a cooling section 102 cooled by the fan 7. The shaft 1 has a columnar internal space 103 extending from the heat-generating section 101 toward the cooling section 102. The internal space 103 is filled with a coolant, and the distance between the inner wall surface S of the internal space 103 and the axis L of the shaft 1 increases continuously from the cooling section 102 toward the heat-generating section 101.

Description

Technical Field

[0001] This invention relates to a motor.

Background Art

[0002] Conventionally, a motor including a shaft, a rotor, a stator, and a fan is known. The rotor is provided on the shaft. The stator is disposed to face the rotor in the radial direction. The fan is provided on the shaft offset axially from the rotor. An internal space in a columnar shape extending axially from a heat generating portion where the rotor is provided to a cooling portion where the fan is provided is formed in the shaft. The internal space of the shaft is filled with a refrigerant. In a portion of the internal space in the heat generating portion of the shaft, heat generated in the stator is transmitted to the heat generating portion, whereby the refrigerant is heated and vaporized. The vaporized refrigerant moves so as to be uniformly distributed throughout the internal space of the shaft. On the other hand, in a portion of the internal space in the cooling portion of the shaft, the fan is cooled and the cooling portion is cooled, whereby the refrigerant is cooled and liquefied. Thereby, the rotor is cooled (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the motor configuration described in Patent Document 1, the distance between the inner wall surface of the shaft's internal space and the shaft's axis remains constant regardless of the axial position. As a result, the refrigerant that is cooled and liquefied in the internal space of the cooling section of the shaft is uniformly distributed axially within the internal space by gravity. Therefore, it is not possible to concentrate and collect the liquefied refrigerant in the heat-generating section. Consequently, there was a problem in that the cooling efficiency of the heat-generating section was poor.

[0005] This invention was made to solve the problems described above, and its purpose is to provide a motor that can improve the efficiency of cooling the heat-generating part in the shaft. [Means for solving the problem]

[0006] The motor according to this invention comprises a shaft, a rotor provided on the shaft, a stator provided opposite to the rotor, and a fan provided on the shaft offset in the axial direction from the rotor. The shaft has a heat-generating section on which the rotor is provided and a cooling section cooled by the fan. The shaft has a columnar internal space extending from the heat-generating section toward the cooling section, and the internal space is filled with a coolant. The distance between the inner wall surface of the internal space and the axis of the shaft increases continuously from the cooling section toward the heat-generating section. In the motor according to this invention, the internal space extends axially from the heat-generating section to the cooling section. In the motor according to this invention, the rotor has a rotor core and a plurality of permanent magnets provided on the rotor core, and the arrangement of the plurality of permanent magnets is in a Halbach arrangement. In the motor according to this invention, the fan is provided in the cooling section. In the motor according to this invention, the cooling unit is arranged such that the airflow generated by the operation of the fan strikes the cooling unit. [Effects of the Invention]

[0007] According to the motor of this invention, the efficiency of cooling the heat-generating part in the shaft can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a motor according to Embodiment 1. [Modes for carrying out the invention]

[0009] Embodiment 1. Figure 1 is a cross-sectional view showing a motor according to Embodiment 1. The motor according to Embodiment 1 comprises a shaft 1, a housing 2, a first bearing 3, a second bearing 4, a rotor 5, a stator 6, a fan 7, a fan 8, a control board 9, and a position sensor 10.

[0010] The shaft 1 is located inside the housing 2. The shaft 1 is rotatably supported in the housing 2 via a first bearing 3 and a second bearing 4.

[0011] The direction along the axis L of shaft 1 is defined as the axial direction D1. The direction along the radius of the circle centered on the axis L of shaft 1 in a plane perpendicular to the axis L of shaft 1 is defined as the radial direction D2. The direction along the circumference of the circle centered on the axis L of shaft 1 in a plane perpendicular to the axis L of shaft 1 is defined as the circumferential direction D3.

[0012] The housing 2 comprises a first cylindrical portion 21, a second cylindrical portion 22, a first support portion 23, a second support portion 24, a first end plate 25, and a second end plate 26.

[0013] The first cylindrical portion 21 is formed in a cylindrical shape. The first cylindrical portion 21 is arranged coaxially with the shaft 1. The second cylindrical portion 22 is formed in a cylindrical shape. The second cylindrical portion 22 is arranged coaxially with the shaft 1. Therefore, the first cylindrical portion 21 and the second cylindrical portion 22 are arranged coaxially with each other. The first cylindrical portion 21 and the second cylindrical portion 22 are arranged side by side in the axial direction D1. The first cylindrical portion 21 and the second cylindrical portion 22 are fixed to each other.

[0014] An air passage 211 is formed in the first cylindrical portion 21, penetrating in the axial direction D1. An air passage 221 is formed in the second cylindrical portion 22, penetrating in the radial direction D2.

[0015] The first support portion 23 is provided at one end of the first cylindrical portion 21 in the axial direction D1. The first support portion 23 is formed integrally with the first cylindrical portion 21. The first support portion 23 may be fixed to the first cylindrical portion 21 via a plurality of fasteners. The first support portion 23 is positioned to extend inward from the first cylindrical portion 21 in the radial direction D2. The first bearing 3 is provided in the inner portion of the first support portion 23 in the radial direction D2.

[0016] The second support portion 24 is provided at the other end of the first cylindrical portion 21 in the axial direction D1. The second support portion 24 is positioned away from the first support portion 23 in the axial direction D1. The second support portion 24 is sandwiched between the first cylindrical portion 21 and the second cylindrical portion 22 in the axial direction D1 and is fixed to the first cylindrical portion 21 and the second cylindrical portion 22 via a plurality of fasteners 11. The second support portion 24 may be formed integrally with the first cylindrical portion 21. The second support portion 24 is positioned to extend inward from the first cylindrical portion 21 in the radial direction D2. A second bearing 4 is provided in the portion of the second support portion 24 that is inward in the radial direction D2.

[0017] The first end plate 25 is provided on the first cylindrical portion 21. The second end plate 26 is provided on the second cylindrical portion 22. The first end plate 25 and the second end plate 26 are arranged such that the first cylindrical portion 21, the second cylindrical portion 22, the first support portion 23, and the second support portion 24 are sandwiched between the first end plate 25 and the second end plate 26. The first end plate 25 is fixed to the first cylindrical portion 21 via a plurality of fasteners 12. Note that the first end plate 25 may be formed integrally with the first cylindrical portion 21. The second end plate 26 is formed integrally with the second cylindrical portion 22. Note that the second end plate 26 may be fixed to the second cylindrical portion 22 via a plurality of fasteners.

[0018] An air flow path 251 penetrating in the axial direction D1 is formed in the first end plate 25. A space through which air passes is formed between the first end plate 25 and the first support portion 23. The space between the first end plate 25 and the first support portion 23 is connected to the air flow path 211 and the air flow path 251.

[0019] An air flow path 261 penetrating in the axial direction D1 is formed in the second end plate 26. The inner space in the second cylindrical portion 22 is connected to the air flow path 221 and the air flow path 261.

[0020] The shape of the rotor 5 is formed in a cylindrical shape. The rotor 5 is arranged coaxially with the shaft 1. The rotor 5 is provided on the shaft 1. Specifically, the rotor 5 is fixed to the outer peripheral surface of the shaft 1.

[0021] The rotor 5 is arranged inside the first cylindrical portion 21 in the radial direction D2. The rotor 5 includes a rotor core 51 and a plurality of permanent magnets 52 provided on the rotor core 51. The shape of the rotor core 51 is formed in a cylindrical shape. The plurality of permanent magnets 52 are arranged on the outer surface of the rotor core 51 in the radial direction D2. The arrangement of the plurality of permanent magnets 52 is a Halbach array. By the arrangement of the plurality of permanent magnets 52 being a Halbach array, the magnetic flux passing through the rotor core 51 can be reduced. Thereby, the rotor core 51 can be configured to be thin, and the space inside the rotor 5 can be utilized more efficiently.

[0022] The stator 6 is disposed inside the first cylindrical portion 21 in the radial direction D2. The shape of the stator 6 is formed in a cylindrical shape. The stator 6 is disposed coaxially with the shaft 1. The stator 6 is disposed so as to face the rotor 5 in the radial direction D2.

[0023] The stator 6 includes a stator core 61 and a plurality of coils 62 provided on the stator core 61. Current is supplied to each coil 62 from a power supply device (not shown). By supplying current to each coil 62, an electromagnetic force in the circumferential direction D3 acts on the rotor 5. Thereby, the rotor 5 rotates in the circumferential direction D3 with respect to the stator 6.

[0024] Also, by supplying current to each coil 62, heat is generated in the stator 6. The heat generated in the stator 6 is transmitted to the shaft 1 via the first support portion 23 and the first bearing 3, and is also transmitted to the shaft 1 via the second support portion 24 and the second bearing 4. Further, the heat generated in the stator 6 is transmitted to the rotor 5 by radiation, and the heat transmitted to the rotor 5 is transmitted to the shaft 1 by heat conduction. Also, when the magnetic flux generated in the stator 6 passes through the rotor 5, heat is generated in the rotor 5. The heat generated in the rotor 5 is transmitted to the shaft 1 by heat conduction.

[0025] The fan 7 is provided on the shaft 1. The fan 7 is disposed between the first cylindrical portion 21 and the first end plate 25 in the axial direction D1. The fan 7 is a centrifugal fan that generates a wind directed outward in the radial direction D2. Therefore, when the fan 7 rotates, an air flow A is generated. The air flow A enters the space between the first cylindrical portion 21 and the first end plate 25 from the outside of the housing 2 through the air flow path 251, and then flows to the outside of the housing 2 through the air flow path 211. The housing 2 is cooled by the air flow A. When the housing 2 is cooled, the stator 6 is cooled.

[0026] Fan 8 is mounted on shaft 1. Fan 8 is positioned inside the second cylindrical portion 22 in the radial direction D2. Fan 8 is an axial flow fan that generates airflow in the axial direction D1. Airflow B is generated when fan 8 rotates. Airflow B enters the inside of the second cylindrical portion 22 from the outside of housing 2 through airflow passage 261, and then flows to the outside of housing 2 through airflow passage 221. The control board 9 is cooled by airflow B.

[0027] The control board 9 is positioned inside the second cylindrical section 22 in the radial direction D2. The control board 9 controls the current supplied from the power supply to each coil 62. The position sensor 10 detects the position of the rotor 5 in the circumferential direction D3 relative to the stator 6. The detection result from the position sensor 10 is output from the position sensor 10 and input to the control board 9. The control board 9 uses the detection result from the position sensor 10 to control the current supplied to each coil 62. This controls the rotational speed of the rotor 5.

[0028] A portion of the shaft 1 along the axial direction D1 is designated as the heat-generating section 101. Specifically, the portion of the shaft 1 where the rotor 5 is located is designated as the heat-generating section 101. The portion of the shaft 1 offset from the heat-generating section 101 along the axial direction D1 is designated as the cooling section 102. Specifically, the portion of the shaft 1 where the fan 7 is located and the portion of the shaft 1 where the fan 8 is located are designated as the cooling section 102. The pair of cooling sections 102 are the portions of the shaft 1 that are cooled by the fan 7 and the fan 8. The heat-generating section 101 is located between the pair of cooling sections 102 along the axial direction D1.

[0029] The shaft 1 has a cylindrical internal space 103 that extends in the axial direction D1 from the heat-generating section 101 to the cooling section 102. The internal space 103 is filled with a coolant. The distance between the inner wall surface S of the internal space 103 and the axis L of the shaft 1 increases continuously from the cooling section 102 towards the heat-generating section 101.

[0030] As current is supplied to each coil 62, heat is generated in the rotor 5 and stator 6. The heat generated in the rotor 5 and stator 6 is transferred to the shaft 1. As a result, the heat-generating part 101 on the shaft 1 is heated.

[0031] As shaft 1 rotates, fan 7 rotates. As fan 7 rotates, fan 7 is cooled. As a result, heat from the part of shaft 1 on which fan 7 is installed is transferred to fan 7 by heat conduction. Therefore, the part of shaft 1 on which fan 7 is installed is cooled. Also, as shaft 1 rotates, fan 8 rotates. As fan 8 rotates, fan 8 is cooled. As a result, heat from the part of shaft 1 on which fan 8 is installed is transferred to fan 8 by heat conduction. Therefore, the part of shaft 1 on which fan 8 is installed is cooled. Through these means, each cooling part 102 on shaft 1 is cooled.

[0032] Next, the operation of the motor according to Embodiment 1 will be described. When current is supplied to the coil 62, the shaft 1 and rotor 5 rotate in the circumferential direction D3 relative to the stator 6. Also, when current is supplied to the coil 62, the heat-generating part 101 of the shaft 1 is heated. As the shaft 1 and rotor 5 rotate relative to the stator 6, the respective cooling parts 102 of the shaft 1 are cooled.

[0033] When the heating element 101 is heated, the liquid refrigerant 100 in the internal space 103 of the heating element 101 is heated by the heating element 101 and vaporizes. The vaporized refrigerant then moves to be uniformly distributed throughout the internal space 103.

[0034] As the cooling unit 102 is cooled, the gaseous refrigerant in the internal space 103 of the cooling unit 102 is cooled by the cooling unit 102 and liquefies. The liquefied refrigerant 100 in the internal space 103 of the cooling unit 102 is subjected to centrifugal force generated by the rotation of the shaft 1. As the distance between the inner wall surface S of the internal space 103 and the axis L of the shaft 1 increases continuously from the cooling unit 102 toward the heat-generating unit 101, the liquefied refrigerant 100 in the internal space 103 of the cooling unit 102 moves toward the heat-generating unit 101. The liquefied refrigerant 100 that has moved toward the heat-generating unit 101 is heated by the heat-generating unit 101 and vaporizes.

[0035] As described above, the motor according to Embodiment 1 comprises a shaft 1, a rotor 5, a stator 6, a fan 7, and a fan 8. The rotor 5 is mounted on the shaft 1. The stator 6 is mounted opposite the rotor 5. The fans 7 and 8 are mounted on the shaft 1 offset from the rotor 5 in the axial direction D1. The shaft 1 has a heat-generating section 101 on which the rotor 5 is mounted, and a cooling section 102 that is cooled by the fans 7 and 8. The shaft 1 has a columnar internal space 103 that extends from the heat-generating section 101 toward the cooling section 102. The internal space 103 is filled with a coolant. The distance between the inner wall surface S of the internal space 103 and the axis L of the shaft 1 increases continuously from the cooling section 102 toward the heat-generating section 101. In this configuration, when the shaft 1 rotates, the refrigerant 100 that has been cooled and liquefied in the internal space 103 of the cooling unit 102 is concentrated and collected in the internal space 103 of the heat-generating unit 101 by centrifugal force. This improves the efficiency of cooling the heat-generating unit 101.

[0036] Furthermore, in the motor according to Embodiment 1, the internal space 103 extends axially D1 from the heat-generating section 101 to the cooling section 102. With this configuration, the gaseous refrigerant can reach the cooling section 102. This allows the gaseous refrigerant to be cooled effectively.

[0037] Furthermore, in the motor according to Embodiment 1, the rotor 5 has a rotor core 51 and a plurality of permanent magnets 52 provided on the rotor core 51. The arrangement of the plurality of permanent magnets 52 is a Halbach arrangement. With this configuration, the magnetic flux passing through the rotor core 51 can be reduced. As a result, the rotor core 51 can be made thinner, and the space inside the rotor 5 can be used more efficiently. Consequently, even if the dimensions of the shaft 1 in the radial direction D2 are increased in order to form an internal space 103 in the shaft 1, it is possible to suppress an increase in the overall dimensions of the motor in the radial direction D2.

[0038] Furthermore, in the motor according to Embodiment 1, fans 7 and 8 are provided in the cooling section 102. With this configuration, the portion of the shaft 1 on which fans 7 and 8 are provided can be cooled by heat conduction.

[0039] In the first embodiment, the motor configuration described included both fan 7 and fan 8. However, the motor is not limited to this configuration. For example, the motor configuration may include either fan 7 or fan 8.

[0040] Furthermore, in the motor according to Embodiment 1, a configuration was described in which the shape of the internal space 103 formed in the shaft 1 is cylindrical. However, the configuration is not limited to this. The shape of the internal space 103 formed in the shaft 1 can be columnar. Even with this configuration, by continuously increasing the distance between the inner wall surface of the internal space 103 and the axis L of the shaft 1 from the cooling section 102 toward the heat-generating section 101, the liquefied refrigerant 100 can be concentrated and collected in the portion of the internal space 103 in the heat-generating section 101 by centrifugal force.

[0041] Furthermore, in the motor according to Embodiment 1, a configuration was described in which the internal space 103 extends in the axial direction D1 from the heat-generating part 101 to the cooling part 102. However, the motor is not limited to this configuration. Any configuration in which the internal space 103 extends from the heat-generating part 101 toward the cooling part 102 is acceptable.

[0042] Furthermore, in the motor according to Embodiment 1, a configuration in which fans 7 and 8 are provided on the cooling unit 102 has been described. However, the configuration is not limited to this. For example, the cooling unit 102 may be arranged such that the airflow generated by the operation of fans 7 and 8 hits the cooling unit 102. Even in this case, the cooling unit 102 is cooled by fans 7 and 8.

[0043] Although a motor according to preferred embodiment 1 has been described above, the motor is not limited to the motor according to embodiment 1 described above. Various modifications and transformations can be made to the motor according to embodiment 1 described above without departing from the scope of the claims. [Explanation of Symbols]

[0044] 1 Shaft, 2 Housing, 3 First bearing, 4 Second bearing, 5 Rotor, 6 Stator, 7 Fan, 8 Fan, 9 Control board, 10 Position sensor, 11 Fastener, 12 Fastener, 21 First cylindrical section, 22 Second cylindrical section, 23 First support section, 24 Second support section, 25 First end plate, 26 Second end plate, 51 Rotor core, 52 Permanent magnet, 61 Stator core, 62 Coil, 100 Liquefied refrigerant, 101 Heating section, 102 Cooling section, 103 Internal space, 211 Air passage, 221 Air passage, 251 Air passage, 261 Air passage.

Claims

1. Shaft (1), A rotor (5) is provided on the shaft (1), A stator (6) is provided opposite to the rotor (5), Fans (7, 8) are mounted on the shaft (1) offset in the axial direction from the rotor (5), Equipped with, The shaft (1) has a heat-generating section (101) on which the rotor (5) is provided, and a cooling section (102) that is cooled by the fans (7, 8). The shaft (1) has a columnar internal space (103) that extends from the heating element (101) toward the cooling element (102). The internal space (103) is filled with a refrigerant. A motor in which the distance between the inner wall surface of the internal space (103) and the axis of the shaft (1) increases continuously from the cooling section (102) towards the heating section (101).

2. The motor according to claim 1, wherein the internal space (103) extends axially from the heat-generating section (101) to the cooling section (102).

3. The rotor (5) is Rotor core (51) and Multiple permanent magnets (52) are provided on the rotor core (51), It has, The motor according to claim 1 or claim 2, wherein the arrangement of the plurality of permanent magnets (52) is a Halbach arrangement.

4. The motor according to claim 1 or claim 2, wherein the fan (7, 8) is provided in the cooling section (102).

5. The motor according to claim 1 or claim 2, wherein the cooling unit (102) is arranged such that the airflow generated by the operation of the fans (7, 8) strikes the cooling unit (102).

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