KR100251883B1 - Structure of inverter and cooling system for high speed electric motor - Google Patents

Abstract

PURPOSE: A structure of inverter and cooling system for a high speed electric motor is provided to be compactificated and effectively radiate heat of a motor as well as enhance the electric reliability and safety between the motor and an inverter by compactificating the inverter to be integrated with the motor. CONSTITUTION: An inverter(7) is disposed within a housing(H) to be closed to one end of a motor(M). A cooling fan(6) is coaxially coupled to a rotary shaft(46) of the motor, and radiates heat generated from the motor(M) by the air flow due to the rotation of the motor. A fan main body has a hub coupled to the rotary shaft(46) in the center of the cooling fan(6). A plurality of flat blades are radially disposed on the peripheral surface of the fan main body.

Description

Inverter integration and cooling structure of high speed electric motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high speed electric motor application, and more particularly to a high speed electric motor application having a built-in inverter and a cooling fan for effectively dissipating heat generated by the motor.

A high speed electric motor is a device that is applied as a power source of a machine or apparatus that requires a high rotational speed by increasing the rotational speed of the motor spindle by increasing the frequency of the input power source. High-speed electric motors that are used in a variety of applications in the industrial field, using 60 Hz commercial power as a power source, is used to accelerate or decelerate using gears or shift by using belt pulleys.

However, high-speed electric motors require the use of ancillary equipment in actual use, resulting in a burden of cost and miniaturization of the overall apparatus. That is, the conventional high speed electric motor application device has the following problems.

First, by using an inverter to control the speed of the motor, the entire apparatus becomes large. Secondly, failure to dissipate the heat generated by the motor efficiently increases the resistance of the motor coil and thermal expansion of the mechanical elements, which risks damaging the coil and breaking the bearing.

An object of the present invention is to provide a high speed electric motor application device capable of reducing the size of the high speed electric motor application device and efficiently dissipating heat generated during operation of the motor.

It is also an object of the present invention to provide a high speed electric motor application apparatus in which the inverter is miniaturized and integrated into the motor, thereby improving the electrical reliability and stability between the motor and the inverter.

The present invention also provides a high speed electric motor application device having a cooling air flow structure that minimizes resistance without forcing air flow at a high speed and a structure capable of promoting air flow to minimize the self-rotation resistance of the fan. The purpose.

According to one aspect of the invention, the housing, a high-speed electric motor installed inside the housing, an output shaft one end protruding out of the housing to install a work tool in the one end, and disposed between the rotation shaft and the output shaft of the motor motor In a high speed electric motor application device comprising a power transmission mechanism for transmitting the rotational force of the rotary shaft to the output shaft, the inverter 7 disposed in the housing close to one end of the motor and the rotation shaft 46 of the motor concentrically A fan body 40 comprising a combined cooling fan 6, the hub having a hub 42 in which the cooling fan 6 is coupled with the rotational shaft 46 of the motor at the center thereof, and an outer periphery of the fan body 40. A high speed electric motor application device is provided comprising a plurality of planar vanes 44 radially disposed on the top.

1 is a schematic cross-sectional view showing a grinder having an inverter, a cooling fan, and a high speed electric motor constructed in accordance with the present invention;

FIG. 2 is an enlarged view of the motor and the cooling fan in FIG. 1, and is an explanatory view showing the air flow by the action of the cooling fan during motor operation; FIG.

Figure 3 shows a cooling fan used in the high speed electric motor application device of the present invention, (a) is a sectional view, (b) is a top plan view, (c) is a bottom view.

<Description of the code | symbol about the principal part of drawing>

6: cooling fan

7: inverter

17: rotor

18: stator

19: wheel shaft

22: work tool

30: condenser

31: electric cable

The present invention will be described with reference to the embodiment of the high speed electric motor application apparatus of the present invention shown in the drawings. Although the illustrated embodiment applies the present invention to an electric grinder, the present invention can be applied to other applications.

1 shows a grinder G comprising a housing H, an inverter 7 and a cooling fan 6 and a high speed electric motor M constructed in accordance with the invention.

The electric grinder G is arranged concentrically with the motor M which consists of the rotor 17 and the stator 18, the inverter 7 arrange | positioned near one end of this motor, and the rotating shaft 46 of a motor. A cooling fan 6. The electric grinder G has an output shaft 48 which is rotated by receiving rotational force from the rotation of the motor by a power transmission mechanism located at the tip of the rotation shaft 46 of the motor, and a work tool 22 such as a polishing wheel connected to the output shaft. And an electric cable 31 for powering the motor and a condenser 30 for charging.

In general, the inverter can be divided into a power unit, a control unit and a cooling unit. Until now, the biggest obstacle to miniaturization of the inverter has been a cooling problem. Conventionally, it was not possible to integrally configure a motor by using a large inverter, but in the present invention, by integrating the motor with a small inverter, the reliability and stability of electrical operation between the motor and the inverter may be improved and its application range may be extended. Made it possible.

Inverter-integrated motor according to the present invention is to apply the concept that the structure of the motor and the inverter complement the concept of the cooling method. That is, by placing the fan connected to the motor on the same air flow arrangement line to cool the motor and the inverter simultaneously, the cooling effect is increased, the housing of the motor serves as the heat sink of the inverter, and the rotational movement of the motor rotor It is designed to move rapidly and intensively the air flow required for cooling.

The fan 6 is concentrically coupled to the rotational shaft 46 of the motor, causing the flow of air while rotating in accordance with the rotation of the motor to dissipate heat generated from the motor to the outside.

Conventionally, a multi-leaf crosslinked forced air flow as a cooling fan (60 ° or more with a stamping bridge formed by the direction in which the blades of the fan cut off the flow of air and the direction of the air when the fan draws air inwards when the air is sucked in). The vane type is mainly used, but the cooling fan of this structure increases the frictional resistance due to the forced linkage of the air flow at a high speed of 10,000 rpm or more, and the cooling efficiency is lowered, and the air resistance acts as a load on the motor rotating shaft. The cause of the reduction and the occurrence of noise.

The smaller the bridge pier is, the smaller the load required for the intake of air, so less energy loss, the amount of air can be increased, and noise can be reduced. Therefore, the present invention adopts an air flow structure that minimizes the flow resistance of the air without excessively forcing the air flow at a high speed and a fan structure that promotes the flow of air and minimizes the rotational resistance of the fan. That is, in the present invention, the fan is configured to suck the air horizontally and discharge it vertically so that the noise is small, the air volume is high, and the energy loss due to the air resistance is very small.

As shown in Fig. 3, the cooling fan 6 according to the present invention has a fan body 40 having a circular plane and having a hub 42 at the center thereof, and a plurality of radially disposed at the outer circumference of the fan body 40. Two planar wings 44. The rotation shaft 46 of the motor is connected to the hub 42. The blade 44 is erected radially from the periphery of the fan body 40 so that a portion thereof extends outward of the periphery. That is, the cooling fan according to the present invention is provided with a flat blade unlike the existing propeller type fan.

As shown in FIG. 2, cooling air for dissipating heat generated inside the motor application device to the outside passes through the motor M by the action of a fan, and absorbs the heat of the motor M and is discharged to the outside. That is, when the air inside the housing H flows out through the outlet 54 by the rotation of the fan, the inside of the housing is depressurized, and the air is introduced into the housing through the inlet 52. Air absorbs heat of the motor while passing through the motor M and is discharged to the outside through the outlet 54. In this process, the contact between the air generated during the movement of the air and the various devices including the cooling object vary in the magnitude of the resistance depending on the inclination angle, and for the ideal flow, the friction inclination angle during the movement should be minimized and uniformly distributed. The contact area of the object to be cooled should be maximized.

In view of this, as shown in Fig. 2, the present invention adopts a structure in which the contact resistance is minimized during the movement of air, and the air moves uniformly and quickly at the minimum inclination angle of the stator and the rotor which are cooling objects. That is, the largest outer surface in the structure of the object to be cooled is the circumferential surface, and since heat distribution of this portion occupies most of the generated heat, heat radiation of this portion can be said to be the core of motor cooling.

The fan structure shown in Fig. 3 is an acute angle bridge type fan having strong suction force and minimum frictional resistance for high-speed air cooling, which is much improved in suction force, suction speed and quietness compared to the conventional front suction. to be.

The fan of this structure is different from the existing fan, especially at high speed, and due to the sharp reduction in the rotating load can bring about a substantial increase in the output efficiency of the motor to save energy.

In addition, as shown in FIG. 1, the inverter built-in grinder according to the present invention adopts a heat radiating outer casing structure in addition to the new introduction of the internal air flow, thereby improving heat dissipation efficiency, uniformly distributing the air input and output parts on the circumference, and in particular, the air. With the diversification of the outlet, the air flow sucked in by the thrust generated from the fan is smoothly discharged, and the effect of preventing the rotation of the fan is eliminated to achieve the cooling and noise suppression effect.

In addition, the function of heat dissipation is effectively arranged in a dual structure of air cooling and heat diffusion by metal, thereby introducing functional separation, and consequently, it greatly contributes to suppressing energy loss and noise increase of high speed electric motor.

In addition, there is a greater significance in the electrical reliability as an integral structure of the motor and the inverter.

As described above, in the high speed electric motor application device of the present invention, the inverter is integrally formed, so that the entire device can be miniaturized.

In addition, by effectively dissipating heat generated from the motor by the action of the cooling fan coupled to the motor main shaft, it is possible to reduce the damage of the coil or the damage of mechanical elements such as the bearing by the heat.

In addition, the high speed electric motor application product can be applied like a general AC motor application product, and it can contribute to the activation of the application of the high speed electric motor by suggesting the conditions further improved in the development and application of the device using the high speed electric motor. For example, the integration of an inverter and a motor facilitates the design and manufacture of a small control device and enables the control of small devices that were not applicable.

In addition, energy savings can be achieved by increasing energy efficiency.

Claims (1)

A high speed electric motor installed inside the housing, an output shaft having one end protruding out of the housing to install a work tool at the one end, and disposed between the rotation shaft of the motor and the output shaft to transfer the rotational force of the motor rotation shaft to the output shaft. In the high speed electric motor application device composed of a power transmission mechanism for transmitting, An inverter 7 disposed inside the housing in proximity to one end of the motor, A cooling fan 6 concentrically coupled to the rotational shaft 46 of the motor, A fan body 40 having a hub 42 in which the cooling fan 6 is coupled to the rotational shaft 46 of the motor at the center thereof, and a plurality of planar vanes radially disposed on the outer periphery of the fan body 40 ( High speed electric motor application, characterized in that it comprises a 44).