The coreless motor belongs to the DC permanent magnet servo control motor, and it can also be classified as a micro motor . The hollow cup motor has outstanding energy-saving characteristics, sensitive and convenient control characteristics and stable operation characteristics, and its technological advancement is very obvious. As a high-efficiency energy conversion device, it represents the development direction of electric motors in many fields.

motor name: coreless motor

type: Belongs to DC, permanent magnet, servo micro motor

feature: ironless rotor

type: Both brushed and brushless

the field t apply: engineering technology

Table of contents

1. 1 Introduction 

2. 2 motor type 

3. 3 Main features 

1.4 Principle _ 

2.5 classification _ 

3.6 Application _ 

1.7 Domestic Development Status 

2. 8 key technologies 

Introduction

The coreless motor breaks through the rotor structure of the traditional motor in structure, and uses an ironless rotor, also called a coreless rotor. This novel rotor structure completely eliminates the power loss caused by the eddy current formed by the iron core.

At the same time, its weight and moment of inertia are greatly reduced, thereby reducing the mechanical energy loss of the rotor itself. Due to the structural change of the rotor, the operating characteristics of the motor have been greatly improved. It not only has outstanding energy-saving characteristics, but more importantly, it has control and drag characteristics that cannot be achieved by iron core motors[1 ]

motor type

Coreless motors are divided into two types: brushed and brushless. The rotor of the brushed coreless motor has no iron core, and the stator of the brushless coreless motor has no iron core. The winding adopts delta connection method [2]

.

main features

Coreless motors mainly have the following characteristics:

1. Energy-saving features: The energy conversion efficiency is very high, and its maximum efficiency is generally above 70%, and some products can reach above 90% (the iron core motor is generally 70%).

2. Control characteristics: fast starting and braking, extremely fast response, mechanical time constant less than 28 milliseconds, and some products can reach within 10 milliseconds (iron core motors are generally above 100 milliseconds); under high-speed operation in the recommended operating area , It is convenient to adjust the speed sensitively.

3. Drag characteristics: the operation stability is very reliable, and the fluctuation of the speed is very small. As a micro motor , the fluctuation of the speed can be easily controlled within 2%.

In addition, the energy density of the coreless motor is greatly improved, and compared with the iron core motor of the same power, its weight and volume are reduced by 1/3-1/2 [2]

.

principle

The coreless motor breaks through the rotor structure of the traditional motor in structure, and uses an ironless rotor, also called a coreless rotor. This rotor structure completely eliminates the power loss caused by the eddy current formed by the iron core, and at the same time its weight and moment of inertia are greatly reduced, thereby reducing the mechanical energy loss of the rotor itself. Coreless motors are DC, permanent magnet, and servo micro motors .

Classification

Coreless motors are divided into two types: brushed and brushless. The rotor of the brushed coreless motor has no iron core, and the stator of the brushless coreless motor has no iron core.

application

Since the coreless motor overcomes the insurmountable technical barriers of the iron core motor, and its outstanding features focus on the main performance of the motor, it has a wide range of applications. Especially with the rapid development of industrial technology, higher expectations and requirements are constantly put forward for the servo characteristics of the motor, so that the coreless motor has an irreplaceable position in many applications.

The application of hollow cup motors has developed rapidly for more than ten years after entering the large industrial and civil fields from the military and high-tech fields, especially in industrially developed countries, and has involved most industries and many products.

1. A follow-up system that requires fast response. Such as the rapid adjustment of the flight direction of the missile, the follow-up control of the high-magnification optical drive, the fast automatic focus, the highly sensitive recording and testing equipment, the industrial robot, the bionic prosthesis, etc., the hollow cup motor can well meet its technical requirements.

2. Products that require smooth and long-lasting dragging of the drive components. Such as all kinds of portable instruments and meters, personal portable equipment, field operation equipment, electric vehicles, etc., with the same set of power supply, the power supply time can be extended by more than double.

3. All kinds of aircraft, including aviation, aerospace, model aircraft , etc. Utilizing the advantages of light weight, small size and low energy consumption of the hollow cup motor, the weight of the aircraft can be reduced to the greatest extent.

4. All kinds of household electrical appliances and industrial products. Using the hollow cup motor as the actuator can improve the product grade and provide superior performance.

5. Taking advantage of its high energy conversion efficiency, it can also be used as a generator; taking advantage of its linear operation characteristics, it can also be used as a tachogenerator ; coupled with a reducer, it can also be used as a torque motor .

With the advancement of industrial technology, the strict technical conditions of various electromechanical equipment put forward higher and higher technical requirements for servo motors. The scope of application on low-end products such as civilian use is to widely improve product quality. According to relevant statistics, more than 100 kinds of civilian products have maturely applied hollow cup motors in industrially developed countries [2]

.

Domestic Development Status

The domestic industry has not yet fully understood the excellent performance of the hollow cup motor, which has hindered the technological progress of electromechanical products in many fields and seriously affected our technical competitiveness with similar foreign products. Many new products developed in China, because the motor performance does not meet the requirements, the overall level of their products has always been far behind similar foreign products, which limits the development and development of many products, such as medical equipment, prosthetics, robots, video cameras, cameras and This phenomenon even exists in some special fields, such as textile machinery and laser measuring instruments . However, due to its complex process, the production of hollow cup motors is far less automated than that of iron core motors, resulting in high production costs, high labor costs, and high requirements for the operator's skill level. Bring many difficulties and restrictions to mass production. The research and development of hollow cup motors in China has a history of 20 to 30 years, but it did not develop rapidly until later. Not only did it replace imported products in the domestic market, but also companies began to participate in the competition in the international market[2 ]

.

key technology

The brushed DC ironless coreless motor incorporates a number of key technologies, such as: low moment of inertia, no cogging, low friction and very compact commutation system, these advantages will bring faster acceleration, higher Efficiency, lower Joule losses and higher continuous torque. Coreless motor technology reduces size, weight and heat, making it ideal for applications such as portable or small devices. This results in better motor performance in a smaller frame size, providing greater comfort and convenience to the end user. Additionally, in battery-powered applications, the ironless design can extend equipment life and improve energy efficiency [1]