An elevator system is a highly coordinated mechanical network in which steel wire ropes in various locations perform distinct mechanical functions. Categorized by their specific roles within the system, their characteristics are as follows:
1. Traction(hoist) Wire Ropes
Core Function: These ropes connect the elevator car to the counterweight and pass over the traction sheave. They rely on friction to drive the vertical movement of the elevator and bear the entire dynamic load (including the self-weight of the car, the rated load, and forces generated during acceleration and deceleration).
Structural Characteristics: High flexibility and fatigue resistance—typically featuring a multi-strand, multi-wire construction (such as the common 8×19S or 8×19W configurations) to ensure excellent fatigue life despite repeated bending over traction and diverter sheaves.
Core Options: Fiber cores (FC/NFC/SFC) are commonly used for low-to-medium-speed elevators, offering good lubricant retention and vibration dampening. Steel cores (IWRC) or composite cores (CSC) are preferred for high-speed, high-rise, or heavy-duty elevators; they provide superior resistance to crushing and exhibit minimal elongation, ensuring precise leveling of the car within the hoistway of high-rise buildings.
Surface Finish: Bright (uncoated/polished).
Safety Standards: Must comply with mandatory standards such as GB 8903, ISO 4344, EN 12385-5, and JIS G3525. These applications require an exceptionally high safety factor (typically no less than 12 when three or more ropes are used).
2. Overspeed Governor Wire Ropes
Core Function: These ropes connect the elevator car to the overspeed governor located at the top of the hoistway (or in the machine room). In the event of an overspeed condition or a free-fall, the governor rope triggers the mechanical action of the overspeed governor, which in turn activates the safety gear to clamp onto the guide rails and bring the car to an emergency stop.
Structural Characteristics: Small diameter—typically ranging from 6 mm to 10 mm—to accommodate the smaller sheave diameters found in overspeed governor assemblies. High flexibility and low elongation: Typically featuring a 6×19S or 8×19S construction with a synthetic fiber core (SFC). The synthetic fiber core is resistant to oil seepage and water absorption; it prevents elongation or contraction caused by humidity fluctuations, ensuring the absolute accuracy of trigger signals.
Lubricant content control: Standards impose strict limits on the lubricant content within the strands (typically 0.50%–1.25%) to prevent excessive grease from causing slippage on the governor sheave.
3. Compensation Wire Ropes
Core function: Suspended between the bottom of the elevator car and the bottom of the counterweight—often in conjunction with a compensation sheave located at the bottom of the elevator shaft. These ropes balance the weight differential of the suspension (traction) ropes that shifts as the elevator moves up and down, ensuring constant tension on both sides of the traction sheave and facilitating smooth operation in high-rise elevators.
Structural characteristics: High flexibility and torsion resistance—due to their placement at the bottom of the shaft and their significant length, these ropes require exceptional flexibility to allow for natural bending. They typically utilize multi-wire, fine-strand constructions such as 6×29F or 6×37M, paired with a fiber core.
Ample lubrication: Unlike traction ropes, compensation ropes do not require high levels of friction against a sheave; therefore, they are more heavily lubricated to extend their service life within the potentially damp environment at the bottom of the shaft.
Alternative solutions: For elevators with speeds of ≤4 m/s, compensation chains (metal chains encased in PVC) are often used instead of compensation ropes to reduce costs and minimize swaying.
4. Door System Wire Ropes
Core function: Used for the opening and closing mechanisms of elevator car doors or landing doors. They connect the door operator motor to the door sliders and must withstand frequent, low-noise reciprocating motion.
Structural characteristics: Extremely fine and highly fatigue-resistant—these ropes typically have very small diameters (1.2 mm–5 mm) and generally feature a 6×7 or 6×19M/WSC construction. Galvanized Anti-Corrosion and Low Elongation: Given that the pulleys on port cranes are extremely small and subject to frequent movement, the wire ropes must possess exceptional straightness, low elongation, and high fatigue life. Typically, a galvanized wire strand core (WSC) is used to prevent rust and control elongation.