Hollow cup motors have outstanding energy-saving characteristics, sensitive and convenient control characteristics, and stable operation characteristics, and their technological advancement is very obvious. As a high-efficiency energy conversion device, it represents the development direction of motors in many fields.
Structure and principle of hollow cup motors The figure below is a schematic diagram of the structure of a general hollow cup motor. Hollow cup motors belong to DC permanent magnet motors. The main difference between ordinary brushed and brushless DC motors is that they use coreless rotors, also called hollow cup rotors.
The rotor is directly wound with wires, and there is no other structure to support these windings. The windings themselves are made into a cup shape, which constitutes the structure of the rotor (as shown below). Due to the structural changes 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 iron core motors cannot achieve.
Hollow cup motors are divided into two types: brushed and brushless. The rotor of the brushed hollow cup motor has no iron core, and the stator of the brushless hollow cup motor has no iron core. Common hollow cup motor models in the market have diameters of Φ4, Φ6, Φ7, Φ8, Φ10, Φ12, Φ15, etc.
Coreless motor magnets
Sintered NdFeB permanent magnets are generally used in coreless motors. They have the characteristics of high remanence, high coercivity, and high magnetic energy products. They are the most suitable permanent magnet materials for coreless motors on the market. Under the same size of motor and wind data, the strength of the magnetic steel performance directly affects the speed of the motor. Common NdFeB magnets suitable for coreless motors are ring-shaped, with performance such as N40, N45, etc., and temperature resistance of about 80℃-100℃.
Advantages and applications of coreless motors
Coreless motors have a series of advantages such as high power density, high efficiency, no torque lag, no cogging effect, low starting torque, no radial force between the rotor and the stator, smooth speed curve, low noise, and good heat dissipation.
1. A follow-up system that requires fast response. For example, the rapid adjustment of the flight direction of missiles, the follow-up control of high-magnification optical drives, rapid automatic focusing, highly sensitive recording and detection equipment, industrial robots, bionic prostheses, etc., hollow cup motors can well meet their technical requirements.
2. Products that require stable and long-lasting dragging of driving components. Such as various portable instruments, personal equipment, instruments and equipment for field operations, electric vehicles, etc., the same set of power supplies can extend the power supply time by more than double.
3. Various aircraft, including aviation, The advantages of hollow cup motors, such as light weight, small size, and low energy consumption, can be used to minimize the weight of aircraft.
4. Various civil electrical appliances and industrial products. Using hollow cup motors as actuators can improve the grade of products and have superior performance.
5. Because hollow cup motors are small in size, many products with relatively small volume requirements use hollow cups as power components. For example; toy gifts (toy cars, model airplanes, etc.), beauty and massage products (face brushes, induction instruments, facial massagers, etc.), daily necessities (electric toothbrushes, shampoo brushes, hair straighteners, etc.).