WO2019189488A1

WO2019189488A1 - Motor

Info

Publication number: WO2019189488A1
Application number: PCT/JP2019/013402
Authority: WO
Inventors: 中村　吉伸
Original assignee: 日本電産株式会社
Priority date: 2018-03-28
Filing date: 2019-03-27
Publication date: 2019-10-03
Also published as: CN111919367A

Abstract

Provided is motor comprising: a rotor having a shaft extending along a center axis; a stator facing the rotor in a radial direction; a housing surrounding the stator; a hermetic chamber provided within the housing and containing a cooling medium; and a pressure regulation device connected to the hermetic chamber. The pressure regulation device has: a pressure regulation section comprising an elastic body in contact with the cooling medium; and a sharp section positioned outside the hermetic chamber and capable of coming into contact with the pressure regulation section.

Description

motor

The present invention relates to a motor.

Conventionally, a motor having a coolant circulation path in a motor is known. Patent Document 1 discloses a configuration in which a coolant is circulated by vaporizing and liquefying the coolant in a sealed space.

Japanese Laid-Open Patent Publication No. 2017-036844

In the case of a motor having a cooling liquid sealed in a sealed space, when abnormal vaporization of the cooling liquid occurs, the internal pressure of the circulation path may increase excessively and the motor may be damaged.

An object of an aspect of the present invention is to provide a motor that can suppress breakage due to vaporization of the coolant.

A motor according to one aspect of the present invention includes a rotor having a shaft extending along a central axis, a stator that is radially opposed to the rotor, a housing that surrounds the stator, and a cooling medium that is provided in the housing and accommodates a cooling medium. A sealed chamber, and a pressure adjusting device connected to the sealed chamber. The pressure adjusting device includes a pressure adjusting portion made of an elastic body that comes into contact with the cooling medium, and a sharp portion that is located outside the sealed chamber and can contact the pressure adjusting portion.

According to the aspect of the present invention, a motor capable of suppressing breakage due to vaporization of the coolant is provided.

FIG. 1 is a cross-sectional view of a rotor blade device including a motor according to an embodiment. FIG. 2 is a perspective view showing the motor with the lid member removed. FIG. 3 is an operation explanatory diagram of the pressure adjusting device. FIG. 4 is a partial cross-sectional view of a modified motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a rotor blade device including a motor according to the present embodiment. FIG. 2 is a perspective view showing a state in which the bearing holder is removed in the motor of the present embodiment. FIG. 3 is an operation explanatory diagram of the pressure adjusting device 100.

In the following description, the vertical direction in which the central axis J shown in FIG. One side of the central axis J in the axial direction is simply referred to as “upper side”, and the other side in the axial direction is simply referred to as “lower side”. The vertical direction is simply a name used for explanation, and does not limit the actual positional relationship or direction. In addition, a direction parallel to the central axis J is simply referred to as “axial direction”, a radial direction around the central axis J is simply referred to as “radial direction”, and a circumferential direction around the central axis J is simply referred to as “circumferential direction”. "

In this specification, “extending in the axial direction” includes not only the case of extending in the axial direction but also the case of extending in a direction inclined by less than 45 ° with respect to the axial direction. “Extending in the radial direction” includes not only strictly extending in the radial direction, that is, in a direction perpendicular to the axial direction, but also extending in a direction inclined by less than 45 ° with respect to the radial direction. .

As shown in FIG. 1, the rotary blade device 1 includes a motor 10, a propeller 2, and a fan 75. The rotary blade device 1 can be used as, for example, a drone rotary blade device. In this embodiment, the fan 75 is a centrifugal fan.
The motor 10 includes a housing 11,

bearings

23 and 24, a rotor 20, a stator 30, a circuit board 80, and a circuit board case 85.

The housing 11 has a cylindrical stator holding member 12 having a bottom wall portion 12 a that opens upward, a lid member 13 connected to the upper end of the stator holding member 12, and a seal positioned at the inner peripheral portion of the stator 30. And a stop member 14. The stator holding member 12 has a bearing holding portion 12b at the center of the bottom wall portion 12a when viewed in the axial direction. The bearing 23 is disposed inside the bearing holding portion 12b. In the case of this embodiment, the bearing holding part 12b has a plurality of through holes 12c penetrating the bearing holding part 12b in the axial direction.

The lid member 13 is fixed to the upper opening of the stator holding member 12. The lid member 13 has a bearing holding portion 13a. The lid member 13 holds the bearing 24 in the bearing holding portion 13a. In the present embodiment, the bearing holding portion 13a has a plurality of through holes 13b penetrating the bearing holding portion 13a in the axial direction. The rotor 20 and the stator 30 are accommodated in an internal space surrounded by the stator holding member 12 and the lid member 13.

The rotor 20 includes a shaft 21 and a rotor body 22. The shaft 21 is disposed along the central axis J. The shaft 21 has a cylindrical shape centered on the central axis J. The shaft 21 is supported by

bearings

23 and 24 so as to be rotatable around the central axis J. The upper end portion of the shaft 21 protrudes upward from the bearing 24. The fan 75 and the propeller 2 are fixed to the tip portion of the shaft 21 that protrudes upward from the lid member 13. The rotor body 22 includes a rotor core that is fixed to the outer peripheral surface of the shaft 21 and a rotor magnet that is fixed to the outer peripheral surface of the rotor core.

The stator 30 is opposed to the rotor 20 in the radial direction through a gap. The stator 30 includes a stator core 31 and a plurality of coils 35. The stator core 31 has an annular shape that surrounds the rotor body 22 on the radially outer side of the rotor body 22. The stator core 31 has a core back 32 and a plurality of teeth 33. The core back 32 has an annular shape centered on the central axis J. The teeth 33 protrude radially inward from the core back 32. The plurality of teeth 33 are arranged at equal intervals over one circumference along the circumferential direction.

The stator core 31 has an insulating layer on the surface of the stator core 31. The insulating layer insulates the coil 35 and the stator core 31. The stator 30 may include an insulator made of a resin molded body. The plurality of coils 35 are attached to each of the plurality of teeth 33.

The stator core 31 has a plurality of first groove portions 32 a extending in the axial direction on the outer peripheral surface of the core back 32. The housing 11 has a plurality of second groove portions 11 a extending in the axial direction on the inner peripheral surface of the stator holding member 12. The 1st groove part 32a and the 2nd groove part 11a are arrange | positioned facing radial direction. The housing 11 has a plurality of outer peripheral flow paths 41 each having a first groove portion 32a and a second groove portion 11a.

The housing 11 has a sealing member 14 located inside the core back 32 in the radial direction. The sealing member 14 seals the opening part which faces the radial inside of adjacent teeth 33. The sealing member 14 is connected to the plurality of column portions 14a extending in the vertical direction at the inner peripheral end of the stator 30, the upper annular portion 14b connected to the upper ends of the plurality of column portions 14a, and the lower ends of the plurality of column portions 14a. A lower annular portion 14c. The upper annular portion 14b and the lower annular portion 14c are annular with the central axis J as the center. The plurality of pillar portions 14a are located between the circumferential directions of the adjacent teeth 33. The rotor 20 is disposed inside the sealing member 14 in the radial direction.

The motor 10 has an inner peripheral flow path 42 surrounded by the adjacent teeth 33 of the stator 30 and the column portion 14a of the sealing member 14. That is, the motor 10 includes a plurality of inner peripheral flow paths 42 positioned between the plurality of teeth 33 in the circumferential direction. The inner peripheral flow path 42 extends along the axial direction and penetrates the stator 30 in the up-down direction.

The lid member 13 has an upper flow path 43 formed of a recess recessed upward on the lower surface side of the lid member 13. The upper flow path 43 is connected to the upper ends of the plurality of outer peripheral flow paths 41 and the upper ends of the plurality of inner peripheral flow paths 42.
The stator holding member 12 has a lower flow path 44 between the stator 30 and the bottom wall portion 12a. The lower flow path 44 is connected to the lower ends of the plurality of outer peripheral flow paths 41 and the lower ends of the plurality of inner peripheral flow paths 42.

The motor 10 has a pressure adjusting device 100 at the bottom of the housing 11.
The pressure adjusting device 100 includes a cylindrical case portion 101 that extends downward from the outer peripheral surface of the bottom wall portion 12a, a sharp portion 102 that is fixed to an opening on the lower side of the case portion 101, and an interior of the case portion 101. And a pressure adjusting unit 103 to be disposed.

The partition wall 12d, which is a part of the bottom wall portion 12a, is located above the case portion 101. The partition wall 12 d partitions the internal space of the case portion 101 and the internal space of the stator holding member 12. The partition wall 12d has a through hole 12e that penetrates the partition wall 12d in the axial direction. The through hole 12 e connects the internal space of the case portion 101 and the internal space of the stator holding member 12.

The sharp portion 102 has a plate-like base portion 104 that expands in the radial direction, and a needle member 105 that protrudes upward from the upper surface of the base portion 104. Base portion 104 is fixed to the lower opening of case portion 101. The base portion 104 has a vent hole 104a that penetrates the base portion 104 in the axial direction.

The pressure adjusting unit 103 is a rubber-like or resin-made elastic sheet. The pressure adjustment unit 103 is fixed by being sandwiched between the case unit 101 and the base unit 104 in the lower opening of the case unit 101. The pressure adjusting unit 103 seals the lower opening of the case unit 101. The plane area of the pressure adjustment unit 103 is larger than the plane area of the lower opening of the case unit 101. The pressure adjustment unit 103 bends upward from the opening of the case unit 101 and is disposed along the inner surface of the case unit 101. An internal space of the case portion 101 that is sealed by the pressure adjusting unit 103 is a pressure adjusting chamber 46 of the pressure adjusting device 100. In the present embodiment, the pressure adjustment chamber 46 is disposed at a position overlapping the stator 30 when viewed in the axial direction. With this configuration, the pressure adjusting device 100 can be installed without increasing the radial dimension of the housing 11.

The motor 10 has a sealed chamber 40 in which a cooling medium is accommodated inside the housing 11. In the present embodiment, the sealed chamber 40 includes a cooling chamber 45 that cools the stator 30 and a pressure adjustment chamber 46 that is partitioned by the cooling chamber 45 and the partition wall 12d. The cooling chamber 45 includes an outer peripheral side channel 41, an inner peripheral side channel 42, an upper channel 43, and a lower channel 44 which are refrigerant channels in the stator holding member 12. In the pressure adjusting chamber 46, the pressure adjusting unit 103 is disposed, and the cooling chamber 45 and the pressure adjusting chamber 46 are connected via a through hole 12e that penetrates the partition wall 12d.

The motor 10 according to the present embodiment includes a sealed chamber 40 in which a cooling medium is accommodated, and a pressure adjusting device 100 connected to the sealed chamber 40. The pressure adjusting device 100 includes a pressure adjusting unit 103 made of an elastic body that comes into contact with a cooling medium, and a sharp portion 102 that is located outside the sealed chamber 40 and can contact the pressure adjusting unit 103.
According to the above configuration, the coil 35 inside the motor 10 can be directly cooled by the cooling medium accommodated in the sealed chamber 40. When the heat generation of the coil 35 is increased, the cooling medium is vaporized, so that the internal pressure of the sealed chamber 40 is increased. In the present embodiment, as shown in FIG. 3, the pressure adjusting unit 103 of the pressure adjusting chamber 46 is deformed by the internal pressure of the cooling medium. Specifically, as shown in FIG. 3, the pressure adjusting unit 103 can be deformed into a convex shape that expands due to the internal pressure of the cooling medium and protrudes toward the sharp part 102 side.

The pressure adjusting unit 103 is deformed in a range not reaching the sharp part 102 during the normal operation of the motor 10, and absorbs the volume change of the cooling medium.
On the other hand, when the internal pressure of the cooling medium increases excessively due to abnormal vaporization of the cooling medium, the pressure adjusting unit 103 protrudes further downward than during normal operation, and the convex tip of the pressure adjusting unit 103 is the sharp part 102. The needle member 105 is contacted. As a result, a hole is made in the pressure adjusting unit 103. A part of the cooling medium is released from the hole formed in the pressure adjusting unit 103, and the internal pressure of the cooling medium is released. As a result, damage to the motor 10 due to the internal pressure of the cooling medium is suppressed.

In the motor 10 of the present embodiment, the sharp part 102 includes a needle member 105. By using the needle member 105, the hole of the pressure adjusting unit 103 can be made to have a minimum size. It is possible to suppress the discharge of the cooling medium more than necessary.

In this embodiment, since the needle member 105 of the sharp portion 102 is applied to the portion that protrudes most when the pressure adjusting portion 103 expands, the sharp portion 102 is applied to the pressure adjusting portion 103 when the internal pressure of the cooling medium increases excessively. Easy to touch. Moreover, the certainty of the hole formation to the pressure adjustment part 103 increases.

In the present embodiment, the cooling chamber 45 and the pressure adjustment chamber 46 are connected via a through hole 12e that penetrates the partition wall 12d. With this configuration, when a hole is formed in the pressure adjusting unit 103, the cooling medium in the cooling chamber 45 flows out to the pressure adjusting chamber 46 through the through hole 12e. Therefore, it is possible to prevent the cooling medium from being discharged to the outside more than necessary.

A bus bar holder 50 is disposed on the bottom surface of the bottom wall portion 12a. The bus bar holder 50 holds a plurality of bus bars 51. The bottom wall portion 12a has a through hole 12e that penetrates the bottom wall portion 12a in the axial direction at a position overlapping the bus bar holder 50 when viewed in the axial direction. Lead wires 35a extending from the plurality of coils 35 extend to the bus bar holder 50 through the through holes 12e. Leader line 35 a is connected to bus bar 51 in bus bar holder 50.

The circuit board case 85 is fixed to the lower part of the housing 11. The circuit board case 85 has a bottom wall and has a cylindrical shape that opens upward. A circuit board 80 is accommodated in the bottom of the circuit board case 85. The circuit board 80 has a plate shape extending in the radial direction. The circuit board 80 is connected to the bus bar 51. The circuit board case 85 has a plurality of openings 85a on the side surface. The pressure adjusting device 100 at the bottom of the housing 11 is located above the circuit board case 85.

In the rotary blade device 1 of the present embodiment, the propeller 2 and the fan 75 are rotationally driven by the motor 10. The fan 75 circulates cooling air inside the motor 10. As the fan 75 rotates, the air above the motor 10 is blown outward in the radial direction, so that the pressure in the vicinity of the bearing 24 on the radial inner side of the fan 75 decreases. Thereby, the air in the circuit board case 85 under the motor 10 moves from the through hole 12c of the bearing holding part 12b to the through hole 13b of the bearing holding part 13a through the periphery of the rotor 20. Therefore, the rotary blade device 1 has a cooling air flow path that enters from the opening 85 a of the circuit board case 85, passes through the inside of the motor 10, and goes out of the fan 75.

(Modification)
FIG. 4 is a partial cross-sectional view of a modified motor. The motor of the modified example includes a rotor having a shaft extending along a central axis, a stator radially opposed to the rotor, a housing surrounding the stator, a sealed chamber provided in the housing and containing a cooling medium, and a sealed A pressure regulator connected to the chamber.
The modified motor includes a pressure adjusting device 200. The pressure adjustment device 200 is disposed at the lower part of the housing 11. The pressure adjustment device 200 includes a cylindrical case portion 201 that extends in the axial direction toward the lower side, a lid portion 202 that is fixed to an opening on the lower side of the case portion 201, and a through-hole 12e in the partition wall 12d. The sealing body 203 that can be closed from the bottom, the support shaft 204 that extends in the axial direction downward from the lower surface of the sealing body 203, and the sealing body 203 and the lid portion 202. A coil spring 205 that pushes from the side.

Also in the motor 10 including the pressure adjusting device 200 of the modified example, the internal pressure of the cooling medium can be adjusted by the pressure adjusting device 200 when the pressure of the cooling medium in the sealed chamber 40 increases. The pressure adjusting device 200 presses the sealing body 203 against the opening of the through hole 12e by the coil spring 205. The cooling medium in the sealed chamber 40 is sealed by the sealing body 203. When the internal pressure of the cooling medium rises due to the heat generation of the coil 35 and the force by which the cooling medium pushes the sealing body 203 exceeds the force by which the coil spring 205 pushes the sealing body 203, the sealing body 203 moves downward. Thereby, the opening part of the through-hole 12e is open | released by air | atmosphere, and a cooling medium is discharge | released from the through-hole 12e. As a result, the internal pressure of the cooling medium is released, and damage to the motor 10 is suppressed. Further, when the internal pressure of the cooling medium returns to a predetermined value, the sealing body 203 returns to the original state. Therefore, the motor 10 can be used repeatedly by replenishing the cooling medium.

In addition, although the motor of this indication was demonstrated based on the inner rotor shown in a figure, it is not restricted to this form. For example, the closed cylindrical rotor may be in the form of an outer rotor located on the radially outer side of the stator. Moreover, although the shaft rotation type motor in which the shaft rotates has been described, a shaft fixed type motor in which the shaft is fixed and the rotor is rotatably supported may be used.

DESCRIPTION OF SYMBOLS 10 ... Motor, 11 ... Housing, 12c, 12e, 13b ... Through-hole, 12d ... Partition, 20 ... Rotor, 21 ... Shaft, 30 ... Stator, 40 ... Sealing chamber, 45 ... Cooling chamber, 46 ... Pressure adjustment chamber, 100 , 200 ... pressure adjusting device, 102 ... sharp part, 103 ... pressure adjusting part, 105 ... needle member, J ... central axis

Claims

A rotor having a shaft extending along a central axis;
A stator radially opposed to the rotor;
A housing surrounding the stator;
A sealed chamber provided in the housing and containing a cooling medium;
A pressure regulator connected to the sealed chamber;
With
The pressure regulator is
A pressure adjusting unit made of an elastic body in contact with the cooling medium;
A sharp portion located outside the sealed chamber and capable of contacting the pressure adjusting portion;
Having a motor.
The motor according to claim 1, wherein the sharp part includes a needle member.
The pressure adjusting part can be deformed into a convex shape that expands due to an internal pressure of the cooling medium and protrudes toward the sharp part,
3. The motor according to claim 1, wherein the sharp portion is disposed so as to be in contact with the convex tip portion of the pressure adjusting portion.
The sealed chamber has a cooling chamber for cooling the stator, and a pressure adjusting chamber partitioned by the cooling chamber and a partition wall,
The pressure adjusting unit is disposed in the pressure adjusting chamber,
The motor according to any one of claims 1 to 3, wherein the cooling chamber and the pressure adjustment chamber are connected via a through-hole penetrating the partition wall.
The motor according to claim 4, wherein the pressure adjusting chamber is disposed at a position overlapping the stator when viewed in the axial direction.