The Hollow Cup Motor is a special type of motor whose main feature is that the rotor of the motor is a hollow cup shape. The motor has the advantages of small size, light weight, fast response and high efficiency, and is widely used in various fields, such as robots, drones, medical equipment and so on.
First, the basic concept of hollow cup motor
1.1 Definition of hollow cup motor
Mico motor is a brushless direct current motor (BLDC) whose rotor is a hollow cup shape, usually made of non-magnetic materials, such as plastic, ceramic, etc. Compared with traditional motors, hollow cup motors have higher power density and better heat dissipation performance.
1.2 Classification of hollow cup motor
According to the rotor structure, the hollow cup motor can be divided into the following types:
(1) Unipolar hollow cup motor: only one magnetic pole, suitable for low power, low speed application scenarios.
(2) Multi-pole hollow cup motor: with multiple magnetic poles, suitable for high power, high speed application scenarios.
(3) Inner rotor hollow cup motor: the rotor is located inside the motor, suitable for applications requiring a compact structure.
(4) External rotor hollow cup motor: the rotor is located outside the motor, suitable for applications requiring large torque.
Second, the structure of the hollow cup motor
2.1 Stator
The stator is a fixed part of the hollow cup motor, usually made of silicon steel sheets laminated to form a plurality of slots. A coil is embedded in the slot to generate a rotating magnetic field through an alternating current. The structure design of the stator has a great influence on the performance of the motor, such as the magnetic flux density, magnetic field distribution and so on.
2.2 Rotor
The rotor is the rotating part of the hollow cup motor, usually made of non-magnetic materials, such as plastic, ceramic, etc. The hollow structure of the rotor can effectively reduce the weight and volume of the motor and improve the power density. A permanent magnet can be installed inside the rotor to generate a magnetic field that interacts with the stator's magnetic field to realize the rotation of the motor.
2.3 Bearing
Bearings are key components that connect the stator and rotor and are used to support the rotation of the rotor. Hollow cup motors usually use high-precision ball bearings or ball bearings to reduce friction and wear and improve the life and stability of the motor.
2.4 Sensor
Sensors are used to detect the position and speed of the rotor in order to control the operation of the motor. Hollow cup motors usually use Hall sensors, photoelectric sensors or magnetic sensors. The precision and response speed of the sensor have a great influence on the performance of the motor.
Third, the working principle of hollow cup motor
3.1 Generation of magnetic field
When alternating current passes through the stator coil, it creates a rotating magnetic field in the stator. This magnetic field passes through the hollow part of the rotor and interacts with the permanent magnet inside the rotor.
3.2 Generation of torque
Due to the interaction of the magnetic field, the rotor is subjected to a moment that causes it to start spinning. The magnitude of this torque is related to the strength of the magnetic field, the number of magnetic poles of the rotor and the current of the motor.
3.3 Control of torque
By changing the current of the stator coil, the strength and direction of the magnetic field can be controlled, thus realizing the precise control of the rotor torque. This control method is called vector control, which can achieve efficient operation and accurate control of the motor.
3.4 Functions of the sensor
The sensor detects the position and speed of the rotor and feeds the information back to the controller. According to these information, the controller adjusts the current of the stator coil to achieve accurate control of the motor.
Four, the characteristics of hollow cup motor
4.1 Small size and light weight
Due to the hollow structure of the rotor, the hollow cup motor has a smaller volume and lighter weight, which is suitable for applications with strict requirements for space and weight.
4.2 Fast response and high efficiency
The rotor inertia of the hollow cup motor is small, which can achieve fast start and stop, and has a high response speed. At the same time, because the flux loss between the rotor and the stator is small, the efficiency of the motor is high.
4.3 Good heat dissipation performance
There is a large air gap between the rotor and the stator of the hollow cup motor, which is conducive to the dissipation of heat. In addition, the rotor's non-magnetic material also helps to reduce heat loss and improve heat dissipation performance.
4.4 Low noise, low vibration
Since there is no contact between the rotor and the stator of the hollow cup motor, there is no friction and wear during operation, so it has low noise and vibration.
Five, hollow cup motor application field
5.1 Robot
Hollow cup motor has the advantages of small size, light weight, fast response, etc., and is widely used in various robots, such as industrial robots, service robots, drones and so on.
5.2 Medical Devices
The high precision and low noise characteristics of hollow cup motors make them ideal for medical devices such as surgical robots, dental equipment, diagnostic equipment, etc.
5.3 Precision Instruments
The high precision and stability of the hollow cup motor make it suitable for a variety of precision instruments, such as optical instruments, measuring instruments, analytical instruments and so on.
5.4 Household Appliances
The high efficiency and low noise characteristics of hollow cup motors make them widely used in household appliances, such as fans, vacuum cleaners, washing machines and so on.
