Spring Coefficient of Office Chair

The parameters related to the 'spring coefficient' of the gas spring in an office chair are mainly reflected through the damping coefficient and force accuracy, with their core function being to control the lifting and buffering performance and stability, rather than the linear stiffness coefficient of traditional mechanical springs.

1. Damping Coefficient: A Key Indicator of Buffering Performance

The damping coefficient is a dynamic parameter achieved through the design of oil flow orifices in the gas spring, directly affecting the smoothness of the lifting process.

• Slow Extension Damping Force: It is required to be no less than 30% of the nominal force. For example, a gas spring with a nominal force of 1000N must have a damping force of ≥300N during slow extension. This design prevents the chair seat from falling rapidly due to gravity, ensuring that the seat rebounds slowly when the user stands up, enhancing safety.
• Rapid Compression Damping Force: It must be controlled within 80% of the nominal force. If a user suddenly sits down, the gas spring needs to limit the compression speed through damping to prevent structural damage or user discomfort due to excessive impact force. For example, a gas spring with a nominal force of 1500N should have a damping force of ≤1200N during rapid compression.

The reasonableness of the damping coefficient depends on design parameters such as oil viscosity and orifice size, and it needs to be experimentally verified to match different usage scenarios (e.g., differences in buffering speed requirements between office and medical settings).

2. Force Accuracy: A Core Parameter for Lifting Matching

Force accuracy refers to the error range between the actual output force of the gas spring and its nominal value, directly affecting the stability of seat lifting.

• Error Control Standard: For high-quality products, the force error should be ≤3%. For example, a gas spring with a nominal force of 1200N should have an actual output force between 1164N and 1236N. If the error is too large, it may cause the seat to jam during lifting under load (insufficient force) or suddenly rebound (excessive force), affecting the user experience.
• Load Matching Logic: The force of the gas spring must strictly correspond to the designed load capacity of the chair seat. The load capacity range of conventional ergonomic chairs is typically 100kg to 150kg (corresponding to a gravitational force of approximately 980N to 1470N), and the force of the gas spring must be precisely matched within this range. If the user's weight exceeds the upper limit of the gas spring's force, it may cause permanent deformation; if it is below the lower limit, the seat cannot be supported.

3. Other Related Parameters: Supplements to Comprehensive Performance

• Nominal Force: The rated load-bearing capacity of the gas spring, typically ranging from 100N to 3000N, determines its applicable scenarios (e.g., light office chairs commonly use 500-1000N, while heavy-duty chairs may require 1500N or more).
• Stroke Length: The extension and retraction range of the gas spring (100-400mm), affecting the height adjustment range of the seat. A longer stroke provides more adjustment space but requires a longer cylinder design, which may increase costs.

Summary: The 'spring coefficient' of the gas spring in an office chair needs to control the dynamic buffering performance through the damping coefficient, ensure lifting stability through force accuracy, and be comprehensively designed in combination with parameters such as nominal force and stroke length to meet the needs of different users and scenarios.