Cooling Structure of Motor

Abstract

A motor cooling structure is provided that can improve the cooling efficiency when cooling a motor that has reached a high temperature. [Solution] In a cooling structure for a motor having a motor placed on a substrate and a propeller rotated by driving the motor, the propeller is formed from a thermally conductive material, and the motor has a stator formed from a thermally conductive material on which a coil is placed and which transfers heat generated from the coil to the substrate, and a rotor formed from a thermally conductive material to which the propeller is connected and combined with the stator, and on which a magnet is placed that generates a magnetic field between itself and the coil placed on the stator and which transfers heat generated from the magnet to the propeller, and the heat transferred from the rotor to the propeller is dissipated as the propeller rotates, and the heat transferred from the stator to the substrate is dissipated into the airflow generated by the rotation of the propeller. [Selected Figure] Figure 1

Description

Technical Field

[0001] The present invention relates to a cooling structure for a motor, and more particularly to a cooling structure for a motor including a motor disposed on a substrate and a propeller rotated by driving the motor.

Background Art

[0002] Generally, a motor is composed of a stator which is a stator having a coil and a rotor which is a rotor having a magnet. The rotor rotates by a magnetic field generated between the coil and the magnet, thereby generating a driving force.

[0003] When the motor generates heat and becomes hot due to the coil and the magnet becoming heat sources by driving such a motor, it is necessary to cool the motor that has become hot because it affects the surrounding devices and equipment where the motor is disposed.

[0004] Patent Document 1 discloses an axial flow fan motor including a motor housed in a motor case, a fan shroud to which the motor is attached via a support member in the motor case, and a propeller disposed on the fan shroud and rotationally driven by the motor.

[0005] According to the axial flow fan motor of this Patent Document 1, since the motor case and the support member that supports the motor housed in the motor case are formed of a heat transfer material, the heat of the motor is transferred from the motor case to the support member and dissipated by the air flow blown out from the propeller via the support member, thereby cooling the motor.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the axial fan motor of Patent Document 1, all of the heat from the motor, which uses coils and magnets as heat sources, is concentrated and transferred to the motor case and support members that house the motor, which can cause the motor case and support members to become hot and reduce the efficiency of heat dissipation.

[0008] Therefore, there is a concern that the axial fan motor of Patent Document 1 may not be able to achieve the desired cooling effect for the motor.

[0009] The present invention has been made in consideration of the above circumstances, and has as its object to provide a motor cooling structure that can improve the cooling efficiency when cooling a motor that has become hot. [Means for solving the problem]

[0010] In order to achieve the above object, the motor cooling structure of the present invention is a cooling structure for a motor that includes a motor placed on a substrate and a propeller that is rotated by driving the motor, wherein the propeller is formed from a heat conductive material, and the motor includes a stator that has a coil placed on it and is formed from a heat conductive material that transfers heat generated from the coil to the substrate, and a rotor that is combined with the stator and to which the propeller is connected, and is formed from a heat conductive material that has a magnet placed on it that generates a magnetic field between it and the coil placed on the stator and transfers heat generated from the magnet to the propeller, and is characterized in that the heat transferred from the rotor to the propeller is radiated by the rotation of the propeller, and the heat transferred from the stator to the substrate is radiated to the airflow generated by the rotation of the propeller.

[0011] According to this motor cooling structure, the stator on which the coils are arranged is formed from a heat-conductive material, and the outer rotor and propeller on which the magnets are arranged are also formed from a heat-conductive material, so that the heat from the motor is dispersed and dissipated according to the coils and magnets that are its heat sources.

[0012] Therefore, when heat is dissipated, the heat of the motor does not concentrate locally, so the efficiency of dissipating heat from the motor is not reduced, and the cooling efficiency of the motor can be improved.

[0013] Furthermore, the heat-conducting member of the motor cooling structure is characterized by being a resin with a thermal conductivity in the range of 0.6 W / mK to 30 W / mK. In this way, since a resin with good thermal conductivity in the range of 0.6 W / mK to 30 W / mK is used as the heat-conducting member, the cooling efficiency of the motor can be further improved.

[0014] Furthermore, the rotor of the motor cooling structure may be an outer rotor that houses the stator, and the motor cooling structure may be mounted on an unmanned flying device. [Effects of the Invention]

[0015] According to the present invention, the cooling efficiency of the motor can be improved. [Brief explanation of the drawings]

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0017] Next, based on FIGS. 1 to 5, a cooling structure of a motor according to an embodiment of the present invention will be described.

[0018] FIG. 1 is a partial cross-sectional view for explaining the outline of the cooling structure of the motor according to the present embodiment, and FIG. 2 is a perspective view for explaining the outline of the cooling structure of the motor according to the present embodiment.

[0019] As shown in the figure, the motor cooling structure 10 includes a substrate 11, a motor 20 disposed on the substrate 11, and a propeller 30 connected to the motor 20.

[0020] The substrate 11 is flat in the present embodiment. The motor 20 disposed on the substrate 11 is a brushless motor without a commutator, and mainly includes a stator 21 and an outer rotor 23 combined with the stator 21.

[0021] The stator 21 is flat following the substrate 10 and includes an annular flange 21a in plan view, a cylindrical boss 21b protruding upward from the flange 21a, and a stator-side bearing 21c provided inside the boss 21b.

[0022] The stator 21 is formed of a heat-conductive member. In the present embodiment, the heat-conductive member is a resin having a thermal conductivity in the range of 0.6 W / mK to 30 W / mK.

[0023] In the present embodiment, the heat-conductive member is, for example, polycarbonate resin, polyamide resin, polybutylene terephthalate resin, polyacetal resin, or modified polyphenylene ether resin, etc., and those produced so that the thermal conductivity is in the range of 0.6 W / mK to 30 W / mK are used.

[0024] In the present embodiment, a plurality of coils 22 are arranged on the peripheral surface of the boss 21b of the stator 21.

[0025] The outer rotor 23 includes a cylindrical rotor case 23A having an upper surface portion 23Aa and a side surface portion 23Ab and open at the bottom, and a rotating shaft 23B that penetrates the rotor case 23A at a substantially central portion of the upper surface portion 23Aa of the rotor case 23A.

[0026] The rotor case 23A of the outer rotor 23 is formed of a heat conductive member. In this embodiment, the heat conductive member is, for example, the same as that of the stator 21, such as polycarbonate resin, polyamide resin, polybutylene terephthalate resin, polyacetal resin, or modified polyphenylene ether resin, etc., and is produced so that the thermal conductivity is in the range of 0.6 W / mK to 30 W / mK.

[0027] In this embodiment, a plurality of magnets 24 are arranged inside the side surface portion 23Ab of the rotor case 23A of the outer rotor 23.

[0028] The stator 21 and the outer rotor 23 are combined, and the rotating shaft 23B of the outer rotor 23 is engaged with the stator side bearing 21c of the stator 21, and the stator 21 is accommodated in the rotor case 23A of the outer rotor 23.

[0029] At this time, when the coil 22 arranged on the stator 21 and the magnet 24 arranged on the outer rotor 23 face each other with a gap therebetween and an electric current is applied to the coil 22 to generate a magnetic field between the coil 22 and the magnet 24, the outer rotor 23 rotates and a driving force by the motor 20 is generated.

[0030] In this embodiment, the propeller 30 includes a propeller side bearing 31 that engages with the rotating shaft 23B of the outer rotor 23, and two blade 32 having a cross-sectional wing shape with a proximal end 32a on the propeller side bearing 31 side and a distal end 32b that is separated from the proximal end 32a. Each blade 32 extends symmetrically so as to be separated from each other from the propeller side bearing 31.

[0031] The propeller 30 is formed of a heat-conductive member. In this embodiment, examples of such a heat-conductive member include polycarbonate resin, polyamide resin, polybutylene terephthalate resin, polyacetal resin, or modified polyphenylene ether resin, which is the same as the stator 21 or the rotor case 23A of the outer rotor 23, and is produced so that the thermal conductivity is in the range of 0.6 W / mK to 30 W / mK.

[0032] The motor 20 with the above configuration is fixed to the substrate 11 by screws 100 at the flange 21a of the stator 21, whereby the motor 20 is arranged on the substrate 11.

[0033] On the other hand, the propeller-side bearing 31 of the propeller 30 is engaged with the rotating shaft 23B of the outer rotor 23, and the propeller 30 and the outer rotor 23 are connected by screws 101.

[0034] Thereby, the cooling structure 10 of the motor of this embodiment is formed.

[0035] Such a motor cooling structure 10 is mounted on an unmanned aerial vehicle 1 such as a so-called drone or multicopter that flies by the rotation of a plurality of propellers, as shown in FIG. 3, in this embodiment.

[0036] This unmanned aerial vehicle 1 includes a fuselage 2 and four arms 3 in a form in which a substrate 11 formed radially from the fuselage 2 is mounted, and at the tip of each of these arms 3, a motor 20 constituting the motor cooling structure 10 and a propeller 30 connected to the motor 20 are mounted.

[0037] FIG. 4 is a block diagram for explaining the hardware configuration of the unmanned aerial vehicle 1 according to this embodiment. As shown in the figure, the unmanned aerial vehicle 1 includes a transmission / reception unit 4, a flight controller 5 connected to the transmission / reception unit 4, a battery 6 that supplies power via the flight controller 5, and a speed control unit (Electronic Speed Controller: ESC) 7 that is connected to the flight controller 5 and controls the motor 20 that drives the propeller 30.

[0038] The transmission / reception unit 4 is a communication interface configured to transmit and receive data from a plurality of external devices such as, for example, a transmitter (prop), an information terminal, a display device, or other remote controllers.

[0039] This transmission / reception unit 4 can utilize a plurality of communication networks such as, for example, a Local Area Network (LAN), a Wide Area Network (WAN), infrared, wireless, WiFi, a Point-to-Point (P2P) network, a telecommunication network, cloud communication, etc.

[0040] Furthermore, the transmission / reception unit 4 executes the transmission and reception of a plurality of data such as various acquired data, processing results generated by the flight controller 5, various control data, user commands from a terminal or a remote controller, etc.

[0041] The flight controller 5 mainly includes a processor 5A, a memory 5B, and sensors 5C.

[0042] [[ID=ID=19]]The processor 5A is configured by, for example, a CPU (Central Processing Unit) in the present embodiment, controls the operation of the flight controller 5, and performs processing such as control of data transmission and reception between each element and processing necessary for program execution.

[0043] The memory 5B includes a main memory device configured by a volatile memory device such as a DRAM (Dynamic Random Access Memory), and an auxiliary memory device configured by a non-volatile memory device such as a flash memory or an HDD (Hard Disc Drive).

[0044] This memory 5B is used as a working area for the processor 5A, while storing various setting information such as logic, code, or program instructions that the flight controller 5 can execute.

[0045] Furthermore, the data acquired from the sensors 5C and the like may be directly transmitted and stored in the memory 5B.

[0046] In this embodiment, the sensors 5C are composed of various sensors such as a GPS sensor that receives radio waves from GPS satellites, a barometric pressure sensor that measures atmospheric pressure, a temperature sensor that measures temperature, and an acceleration sensor.

[0047] When such an unmanned aircraft 1 flies at high speed or for a long time, for example, a large driving force is required for the motor 20. Therefore, the coil 22 arranged on the stator 21 and the magnet 24 arranged on the rotor case 23A of the outer rotor 23 become heat sources, and the motor 20 may generate heat and become hot.

[0048] In this case, in the motor cooling structure 10 of this embodiment, as shown in FIG. 5, the heat H1 with the coil 22 as the heat source is transferred to the boss 21b of the stator 21 formed by a heat conductive member, and the heat H1 transferred to the boss 21b is transferred to the flange 21a.

[0049] The heat H1 transferred to the flange 21a is transferred to the arm 3 (substrate 11), and the heat H1 transferred to the arm 3 (substrate 11) is dissipated to the air flow A generated by the rotation of the propeller 30.

[0050] On the other hand, the heat H2 with the magnet 24 as the heat source is transferred to the side surface portion 23Ab of the rotor case 23A of the outer rotor 23 formed by a heat conductive member, and the heat H2 transferred to the side surface portion 23Ab of the rotor case 23A is transferred to the upper surface portion 23Aa of the rotor case 23A.

[0051] The heat H2 transferred to the upper surface portion 23Aa of the rotor case 23A is transferred to the propeller 30 formed by a heat conductive member via the rotating shaft 23B, and the heat H2 transferred to the propeller 30 is dissipated into the air by the rotation of the propeller 30.

[0052] In this way, since the stator 21 where the coil 22 is disposed is formed of a heat conductive member, and the rotor case 23A of the outer rotor 23 where the magnet 24 is disposed and the propeller 30 are formed of a heat conductive member, the heat of the motor 20 is dispersed and radiated according to each of the coil 22 and the magnet 24 serving as its heat sources.

[0053] Therefore, when radiating heat, since the heat of the motor 20 does not locally concentrate, it does not cause a decrease in the heat radiation efficiency of the motor 20, and the cooling efficiency of the motor 20 can be improved.

[0054] Moreover, in this embodiment, since a resin having good heat conduction efficiency with a thermal conductivity in the range of 0.6 W / mK to 30 W / mK is used as the heat conductive member, the cooling efficiency of the motor 20 can be further improved.

[0055] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention. In the above embodiment, the case where the rotor of the motor 20 is the outer rotor 23 has been described, but a motor provided with an inner rotor that rotates inside the stator may also be used.

[0056] In the above embodiment, the case where the motor cooling structure 10 is mounted on the unmanned aerial vehicle 1 has been described, but it is not limited to the case of being mounted on the unmanned aerial vehicle 1, and it can be used in various devices that rotate a propeller using a motor as a drive source.

[0057] In the above embodiment, the case where the blades 32 of the propeller 30 are two has been described, but it is not limited to two, and a propeller with an appropriate number of blades can be used according to the application.

[0058] In the above embodiment, the case where the propeller 30 is connected to the outer rotor 23 by the screw 101 has been described, but it may be configured to be connected by fitting the propeller side bearing 31 into the rotating shaft 23B without using the screw 101.

Explanation of Reference Numerals

[0059] 1 Unmanned aircraft device 2 Airframe 3 Arm (substrate) 5 Flight controller 10 Motor cooling structure 11 Substrate 20 Motor 21 Stator 22 Coil 23 Outer rotor 23A Rotor case 23B Rotating shaft 24 Magnet 30 Propeller 31 Propeller side bearing 32 Blade A Airflow H1, H2 Heat

Claims

In a cooling structure of a motor including a motor disposed on a substrate and a propeller rotated by driving of the motor, the propeller is formed of a heat conductive member, the motor includes a stator formed of a heat conductive member in which a coil is disposed and heat generated from the coil is transferred to the substrate, a rotor formed of a heat conductive member in which a magnet is disposed to generate a magnetic field between the stator and the coil disposed in the stator and the magnet is combined with the stator and heat generated from the magnet is transferred to the propeller, heat transferred from the rotor to the propeller by rotation of the propeller is dissipated, and heat transferred from the stator to the substrate is dissipated to an air flow generated by rotation of the propeller, the rotor is an outer rotor that houses the stator, a propeller-side bearing of the propeller is engaged with a rotation shaft of the outer rotor, and the propeller and the outer rotor are connected by a screw that penetrates the propeller-side bearing and engages with an upper surface portion of a rotor case of the outer rotor, an air vent hole communicating with the inside of the rotor case is not formed on the upper surface portion of the rotor case except for a hole through which the rotation shaft passes and a hole through which the screw passes, the heat conductive member is a resin having a thermal conductivity in a range of 0.6 W / mK to 30 W / mK. A cooling structure of a motor characterized by that.

2. The cooling structure of the motor according to claim 1, wherein the stator has a flange fixed to the substrate by screws.

3. The cooling structure of the motor according to claim 1 or 2, characterized in that it is mounted on an unmanned aerial vehicle. In a cooling structure of a motor including a motor disposed on a substrate and a propeller rotated by driving of the motor, the propeller is formed of a heat conductive member, the motor includes a stator formed of a heat conductive member in which a coil is disposed and heat generated from the coil is transferred to the substrate, a rotor formed of a heat conductive member in which a magnet is disposed to generate a magnetic field between the stator and the coil disposed in the stator and the magnet is combined with the stator and heat generated from the magnet is transferred to the propeller, The heat transferred from the rotor to the propeller by the rotation of the propeller is dissipated, and the heat transferred from the stator to the substrate is dissipated to the air flow generated by the rotation of the propeller. The rotor is an outer rotor that houses the stator, the propeller-side bearing of the propeller is engaged with the rotation axis of the outer rotor, and the propeller and the outer rotor are connected by a screw that passes through the propeller-side bearing and engages with the upper surface portion of the rotor case of the outer rotor. On the upper surface portion of the rotor case, except for the hole through which the rotation axis passes and the hole through which the screw passes, there are no vent holes formed that communicate with the inside of the rotor case. The propeller is a cooling structure of a motor, characterized in that it is formed of a polycarbonate resin, a polyamide resin, a polybutylene terephthalate resin, a polyacetal resin, or a modified polyphenylene ether resin.

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