Working principle of gearless traction machine

The working principle of gearless traction machine is as follows:

Basic Components

The gearless traction machine mainly consists of a permanent magnet synchronous motor, braking system, and traction wheel. The traction wheel and brake wheel are coaxially fixed and connected, and are directly installed on the motor shaft extension. The braking system is composed of the brake body, brake wheel, brake arm, and brake shoe, etc.

Working Principle

1. Starting Stage

When the elevator control system issues a start command, the inverter provides three-phase variable frequency and variable voltage power according to the feedback from the encoder, generating a rotating magnetic field. This causes the motor rotor, made of rare earth permanent magnetic materials, etc., to rotate at synchronous speed, directly driving the traction wheel.

The traction wheel drives the steel wire rope through friction, thus realizing the up and down movement of the elevator car. For example, when the traction wheel rotates clockwise, the steel wire rope on the car side is driven upward by the traction wheel, and the steel wire rope on the counterweight side moves downward, making the car rise.

2. Running Stage

During the operation of the elevator, the permanent magnet synchronous motor continuously provides stable torque, driving the car and counterweight to run smoothly through the friction between the traction wheel and the steel wire rope. The inverter adjusts the operating parameters of the motor in real time according to the running speed, load and other factors of the elevator, ensuring the smooth operation of the elevator.

Due to the characteristics of linear and constant torque and adjustable speed of the permanent magnet synchronous motor, the traction wheel can run smoothly, with low noise and low energy consumption.

3. Stopping Stage

When the elevator reaches the target floor, the control system issues a stop command. The motor is powered off and stops rotating, and at the same time, the brake electromagnet is powered off. The brake loses magnetic suction, and the spring pushes the armature to press the friction disc tightly, generating a braking torque to quickly stop the traction wheel, making the car stop at the corresponding position.

The braking process of the brake should be quick and smooth to avoid excessive impact and vibration of the elevator. The brake armature is divided into two parts, left and right, and two sets of springs act on the armature and friction disc respectively, in accordance with the double braking requirement of the elevator brake.

Advantages

1. High Efficiency and Energy Saving: There is no power loss of gear transmission, and the mechanical efficiency is high.
2. Low Noise: Low-speed direct drive, low bearing noise, no fan and gear transmission noise, noise can generally be reduced by 5 - 10 dB.
3. Small Size: Simple structure, gear reducer is cancelled, small size, convenient for installation and maintenance.
4. Smooth Operation: The permanent magnet synchronous motor has the characteristics of constant torque and adjustable speed, making the traction wheel run smoothly.
5. Maintenance-free: Using high-performance permanent magnetic materials and special motor structure, basically no maintenance is required.

Application Range

Gearless traction machines are suitable for driving various passenger elevators, medical elevators and passenger and freight elevators controlled by frequency conversion devices.