JP2024013100A - motor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique of improving the cooling performance of a motor.

SOLUTION: A moto unit includes a motor, a fan that sends gas to the motor, and magnetic cooling means that cools the gas to be sent to the motor. The magnetic cooling means includes a permanent magnet, and a magnetic body that moves between a first position to which a magnetic field generated by the permanent magnet is applied and a second position which is separated from the first position and at which a temperature decreases due to a magneto-caloric effect. The second position is set between the motor and the fan.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a motor unit including a motor.

As a technique for cooling a motor, a technique for cooling the motor by blowing air from a fan is known (Patent Document 1).

Patent application 2019-144509

However, there is room for improvement in cooling the motor with a fan.

An object of the present invention is to provide a technique for improving cooling performance of a motor.

According to the invention,
motor and
a fan that blows gas to the motor;
magnetic cooling means for cooling the gas blown to the motor;
The magnetic cooling means
permanent magnet and
a magnetic body that moves between a first position where a magnetic field by the permanent magnet is applied and a second position that is spaced from the first position and whose temperature decreases due to a magnetocaloric effect;
the second position is set between the motor and the fan;
A motor unit is provided.

According to the present invention, it is possible to provide a technique for improving cooling performance of a motor.

FIG. 1 is a sectional view of a motor unit according to an embodiment of the present invention. (A) to (D) are operation explanatory diagrams of the magnetic cooling unit. FIG. 3 is a sectional view of a motor unit according to another embodiment. FIG. 7 is a sectional view of a motor unit according to yet another embodiment. FIG. 5 is an explanatory diagram of the magnetic cooling unit in the embodiment of FIG. 4.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar configurations are given the same reference numerals, and duplicate explanations will be omitted.

<First embodiment>
FIG. 1 is a sectional view of a motor unit 1 according to an embodiment of the present invention. The motor unit 1 includes an electric motor M. The motor M is a brushless motor including a rotor 2 and a stator 3 surrounding the rotor 2. The rotor 2 includes a cylindrical permanent magnet 21 and a rotor shaft 22 passing through the center of the permanent magnet 21. Stator 3 includes a stator core 31 and a coil 32 wound around stator core 31. The rotor 2 rotates by supplying electric power to the coil 32. Arrow X indicates the axial direction of the rotor shaft 22, and arrow R indicates the radial direction (any direction perpendicular to the X direction) with respect to the rotor shaft 22.

The motor unit 1 includes a fan 4 that blows gas to the motor M, and a magnetic cooling unit 5 that cools the gas that is blown to the motor M by the fan 4. In this embodiment, the fan 4 is fixed to the rotor shaft 22 and blows gas in the X direction. In this embodiment, the gas is air.

The motor unit 1 includes a hollow housing 6, and the motor M, the fan 4, and the magnetic cooling unit 5 are housed in the housing 6. The housing 6 includes a peripheral wall 6a having a cylindrical shape coaxial with the rotor shaft 22, and end plates 6b and 6c that close both ends of the peripheral wall 6a in the X direction. Bearings 64 that support the rotor shaft 22 are provided on the end plates 6b and 6c, respectively. A vent hole 61 for introducing outside air into the housing 6 is formed in the end plate 6b. The end plate 6c is provided with a vent 62 for discharging the air inside the housing 6 to the outside. The peripheral wall 6a is also provided with a vent 63 for discharging the air inside the housing 6 to the outside.

When the motor M is driven, the fan 4 rotates together with the rotor shaft 22. The rotation of the fan 4 generates an airflow inside the housing 6 from the fan 4 toward the motor M, and outside air is introduced into the housing 6 through the vent 61 as shown by arrow D1, and as shown by arrow D2. Then, air is discharged from inside the housing 6 to the outside of the housing 6 through the vent 62. The motor M is cooled by this air flow.

The magnetic cooling unit 5 cools the air flowing from the fan 4 toward the motor M using the magnetocaloric effect. Thereby, the cooling performance of the motor M can be improved. The magnetic cooling unit 5 includes a pair of permanent magnets 51, a magnetic body 52, and a moving mechanism 53 that moves the magnetic body 52. The pair of permanent magnets 51 are arranged in the housing 6 at positions spaced apart from the rotor shaft 22 in the R direction and spaced apart from each other in the X direction. The pair of permanent magnets 51 generate a magnetic field in the X direction in the space between them.

The magnetic material 52 is, for example, a gadolinium alloy or the like, and in this embodiment, has a cylindrical shape, for example. The magnetic body 52 is moved between the position P1 and the position P2 by the moving mechanism 53. At position P1, the magnetic body 52 is located between the pair of permanent magnets 51, and a magnetic field by the pair of permanent magnets 51 is applied. Position P2 is spaced apart from position P1, and is a position where the magnetic body 52 has escaped from between the pair of permanent magnets 51. Position P1 and position P2 are spaced apart in the R direction, and position P1 is outside position P2 when viewed from rotor shaft 22. Due to the magnetocaloric effect, the temperature of the magnetic body 52 decreases at position P2. That is, the magnetic body 52 has a relatively high temperature at the position P1, and a relatively low temperature at the position P2.

Position P2 is set between motor M and fan 4. The airflow from the fan 4 toward the motor M is cooled by the magnetic body 52 located at position P2, and lower temperature air can be sent to the motor M. While the motor M generates heat due to its driving and becomes higher than normal temperature, the position P2 is located closer to the rotor shaft 22 in the R direction than the position P1, so the airflow toward the motor M is at the position P2. The magnetic body 52 allows more efficient cooling. Since the vent 63 is formed in the peripheral wall 6a adjacent to the position P1, the air inside the housing 6 heated by the heat near the position P1 is easily discharged to the outside through the vent 63. The heat dissipation mechanism of the magnetic body 52 at the position P1 allows the temperature of the magnetic body 52 at the position P2 to be lower, and the airflow of the fan 4 can be further cooled.

In the case of this embodiment, the moving mechanism 53 causes the magnetic body 52 to reciprocate between the position P1 and the position P2 using the driving force of the motor M. Although the moving mechanism 53 may have its own driving source, by using the driving force of the motor M, the motor unit 1 can be made more compact and lower in cost. The moving mechanism 53 of this embodiment is a conversion mechanism that converts the rotational motion of the rotor shaft 22 into a reciprocating linear motion of the magnetic body 52 in the R direction.

Specifically, the moving mechanism 53 includes a crank portion 54 integrally formed with the rotor shaft 22, a connecting rod 55, a moving member 56, and a cylinder 58. The moving member 56 supports the magnetic body 52. The moving member 56 and the magnetic body 52 constitute a piston and reciprocate in the R direction under the guidance of the cylinder 58. The cylinder 58 has a cylindrical shape and is supported by the housing 6 via a support member (not shown). The cylinder 58 is made of, for example, aluminum or iron. The cylinder 58 may be made of a material with high thermal conductivity in terms of removing heat from the magnetic body 52. A hole through which the crank portion 54 is inserted is formed at one end of the connecting rod 55 . The other end of the connecting rod 55 is formed with a hole through which the piston pin 57 of the moving member 56 is inserted. Therefore, the connecting rod 55 is rotatable with respect to the crank portion 54 and also rotatable with respect to the moving member 56.

2(A) to FIG. 2(D) are explanatory diagrams of the operation of the magnetic cooling unit 5, and are views of the magnetic cooling unit 5 viewed in the direction A of FIG. Cylinder 58 is shown in cross-section. 2(A) to 2(D) show how the crank portion 54 rotates due to the rotation of the rotor shaft 22, and the moving member 56 reciprocates in the R direction. FIG. 2(A) shows a state in which the magnetic body 52 is located at position P2. The magnetic body 52 is partially removed from the cylinder 58. FIG. 2(B) shows a state in which the rotor shaft 22 has been rotated by 90 degrees from the state in FIG. 2(A). The magnetic body 52 is moving toward the pair of permanent magnets 51. FIG. 2(C) shows a state in which the rotor shaft 22 has been rotated 90 degrees from the state in FIG. 2(B). The magnetic body 52 is moving between the pair of permanent magnets 51 and has reached position P1. FIG. 2(D) shows a state in which the rotor shaft 22 has been rotated 90 degrees from the state in FIG. 2(C). The magnetic body 52 is moving in a direction from position P1 to position P2. When the rotor shaft 22 rotates 90 degrees from the state shown in FIG. 2(D), it returns to the state shown in FIG. 2(A). As described above, in this embodiment, when the rotor shaft 22 rotates once, the magnetic body 52 reciprocates once between the position P1 and the position P2.

In this embodiment, as the magnetic body 52 repeatedly moves to the position P2 as the motor M rotates, the airflow from the fan 4 toward the motor M can be continuously cooled while the motor M is being driven. can.

<Second embodiment>
Structurally, the air that has come into contact with the magnetic body 52, which has become relatively hot at the position P1, may be made difficult to flow to the motor M. FIG. 3 shows an example. In the motor unit 1 of FIG. 3, a partition wall 7 is provided inside the housing 6. The partition wall 7 is a cylindrical body coaxial with the rotor shaft 22, and has a large diameter on the motor M side and a small diameter on the fan 4 side.

The internal space near the motor M of the housing 6 is partitioned by the partition wall 7 into a space 71 outside the partition wall 7 and a space 72 inside. Line L indicates the position of the end of partition wall 7 on the fan 4 side in the R direction, and is located between position P1 and position P2. Therefore, the space 71 is the space on the side of position P1, and the space 72 is the space on the side of position P2.

Among the airflows flowing from the fan 4 to the motor M, the air that has been cooled by contacting the magnetic body 52 at the position P2 flows easily into the space 72, and cooling of the motor M is promoted. On the other hand, among the airflow flowing from the fan 4 to the motor M, the air that is not cooled by contacting the magnetic body 52 at the position P1 tends to flow into the space 71 and is easily discharged to the outside of the housing 6 without contacting the motor M. . Therefore, the cooling efficiency of the motor M can be improved.

<Third embodiment>
A plurality of pairs of permanent magnets 51, magnetic bodies 52, and moving mechanisms 53 may be provided. FIGS. 4 and 5 show an example. FIG. 4 shows a cross-sectional view of the motor unit 1 of this embodiment, and FIG. 5 is a view of the magnetic cooling unit 5 seen in the B direction of FIG. 4, in which the cylinder 58 is shown in a cross-sectional shape. Arrow C indicates the circumferential direction with respect to the rotor shaft 22. The magnetic cooling unit 5 of this embodiment includes four sets of a pair of permanent magnets 51, a magnetic body 52, and a moving mechanism 53, and each set is spaced apart by 90 degrees in the C direction.

The four connecting rods 55 are attached to a common crank part 54. The phases of the reciprocating motion of each set of magnetic bodies 52 are shifted by 90 degrees. In the example of FIG. 5, the set of magnetic bodies 52 at the 12 o'clock position on the clock face is at position P2, and the set of magnetic bodies 52 at the 6 o'clock position is at position P1. Further, each of the magnetic bodies 52 in the 3 o'clock position group and the 9 o'clock position group is located at an intermediate position between position P1 and position P2. As in the case of the first embodiment, each magnetic body 52 reciprocates once between the position P1 and the position P2 when the rotor shaft 22 rotates once.

In this embodiment, the four magnetic bodies 52 sequentially move to the position P2 as the motor M rotates, so that the airflow from the fan 4 toward the motor M is continuously cooled while the motor M is being driven. be able to.

<Summary of embodiments>
The above embodiments disclose at least the following motor units.

1. The motor unit (1) of the above embodiment is
Motor (M) and
a fan (4) that blows gas to the motor;
magnetic cooling means (5) for cooling the gas blown to the motor;
The magnetic cooling means (5) includes:
A permanent magnet (51),
A magnetic body that moves between a first position (P1) where a magnetic field is applied by the permanent magnet and a second position (P2) that is spaced from the first position and whose temperature decreases due to a magnetocaloric effect. (52) and,
The second position (P2) is set between the motor (M) and the fan (4).
According to this embodiment, it is possible to provide a technique for improving the cooling performance of a motor.

2. In the above embodiment,
The fan (4) blows air in the axial direction of the rotor shaft (22) of the motor (M),
The second position (P2) is located closer to the rotor shaft (22) than the first position (P1) in the radial direction of the rotor shaft (22).
According to this embodiment, the airflow to the motor can be efficiently cooled.

3. In the above embodiment,
The magnetic body (52) moves between the first position (P1) and the second position (P2) by the driving force of the motor (M).
According to this embodiment, it is possible to reduce the size and cost of the motor unit.

4. In the above embodiment,
The magnetic cooling means (5) includes:
A conversion means (53) is provided for converting the rotational motion of the rotor shaft (22) of the motor (M) into a reciprocating linear motion of the magnetic body (52) in the radial direction.
According to this embodiment, the magnetic body (52) can be repeatedly moved by the driving force of the motor (M).

5. In the above embodiment,
The magnetic cooling means (5) includes:
A plurality of sets of the permanent magnet (51) and the magnetic body (52) are provided,
The plurality of sets are arranged in a circumferential direction with respect to the axial direction.
According to this embodiment, the cooling performance of the motor can be improved.

6. The motor unit (1) of the above embodiment is
a partition wall (7) that partitions the internal space of the motor unit (1) into a space (71) on the first position (P1) side and a space (72) on the second position (P2) side; ).
According to this embodiment, the cooling efficiency of the motor can be improved.

Although the embodiments of the invention have been described above, the invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the gist of the invention.

1 motor unit, M motor, 4 fan, 5 magnetic cooling unit

Claims (6)

motor and
a fan that blows gas to the motor;
magnetic cooling means for cooling the gas blown to the motor;
The magnetic cooling means
permanent magnet and
a magnetic body that moves between a first position where a magnetic field by the permanent magnet is applied and a second position that is spaced from the first position and whose temperature decreases due to a magnetocaloric effect;
the second position is set between the motor and the fan;
A motor unit characterized by: The motor unit according to claim 1,
The fan blows air in the axial direction of the rotor shaft of the motor,
The second position is located closer to the rotor shaft in the radial direction of the rotor shaft than the first position.
A motor unit characterized by: The motor unit according to claim 1,
The magnetic body moves between the first position and the second position by the driving force of the motor.
A motor unit characterized by: The motor unit according to claim 2,
The magnetic cooling means
comprising a converting means for converting the rotational motion of the rotor shaft of the motor into reciprocating linear motion of the magnetic body in the radial direction;
A motor unit characterized by: The motor unit according to claim 4,
The magnetic cooling means
A plurality of sets of the permanent magnet and the magnetic body are provided,
The plurality of sets are arranged in a circumferential direction with respect to the axial direction,
A motor unit characterized by: The motor unit according to claim 1,
comprising a partition wall that partitions the internal space of the motor unit into a space on the first position side and a space on the second position side;
A motor unit characterized by:

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