Detailed Explanation of Elevator Traction System

The Elevator traction system is the core part of the elevator operation, mainly composed of the following key components:

●Traction machine: The traction machine is the power source of the elevator, usually composed of a motor, a brake and a reduction gearbox. The motor provides power, the brake ensures safety, and the reduction gearbox ensures the smooth operation of the elevator by decelerating.

●Traction wire rope: The traction wire rope connects the car and the counterweight, transmits power through the friction between the traction wheel, and drives the car up and down. It is the "skeleton" of the elevator, ensuring that the elevator can run up and down smoothly.

●Guide wheel: The guide wheel is installed on the traction machine frame or load-bearing beam to guide the traction rope to the counterweight or car to ensure that the elevator will not deviate in the vertical direction.

●Anti-ropes: The anti-ropes help the elevator run more smoothly by increasing the traction force.

Classification by deceleration method

●Geared traction machine: The power of the traction device is transmitted to the traction machine on the traction wheel through an intermediate reducer. The reducer usually adopts worm gear transmission (also uses helical gear transmission). The motors used in this traction machine are AC and DC, and are generally used in low-speed elevators. The traction ratio is usually 35:2. If the motor power of the traction machine is transmitted to the traction wheel through a reducer, it is called a geared traction machine, which is generally used in low- and medium-speed elevators below 2.5m/s.

●Gearless traction machine: The power of the traction device is directly transmitted to the traction machine on the traction wheel without an intermediate reducer. In the past, most of these traction machines were powered by DC motors. China has developed AC permanent magnet synchronous gearless traction machines with independent intellectual property rights. The traction ratio is usually 2:1 and 1:1. Load 320kg~2000kg, elevator speed 0.3m/s~4.00m/s. If the power of the motor is not transmitted to the traction wheel through the reduction gearbox, it is called a gearless traction machine, which is generally used for high-speed elevators and ultra-high-speed elevators above 2.5m/s.

Classification by driving motor

●DC traction machine can be divided into DC geared traction machine and DC gearless traction machine.

●AC traction machine can be divided into AC geared traction machine, AC gearless traction machine and permanent magnet traction machine. Among them, AC traction machine can also be subdivided into: worm pair traction machine, cylindrical gear pair traction machine, planetary gear pair traction machine, other gear pair traction machine.

Classification by speed

1. Low speed traction machine (ν<1m/s)
2. Medium speed traction machine (fast traction machine) (ν=1m/s~2m.s)
3. High speed traction machine (ν=2m/s~5m/s)
4. Ultra-high speed traction machine (ν>5m/s)

Working principle

The traction drive relationship of traction elevator is shown in the figure. The motor installed in the machine room, together with the reduction box, brake, etc., forms a traction machine, which is the power of the traction drive. The traction wire rope is connected to the car through the traction wheel at one end and the counterweight at the other end. In order to make the car and the counterweight in the hoistway run along the guide rail in the hoistway without rubbing against each other, a guide wheel is placed on the traction machine to separate the two. The gravity of the car and the counterweight device causes the traction wire rope to be pressed tightly in the traction wheel groove to generate friction. In this way, the rotation of the motor drives the traction wheel to rotate, driving the wire rope, dragging the car and the counterweight to move relative to each other.