Definition & Symbols of Compression Gas Springs

Posted by: harry | on February 18, 2025

3. Terms, Definitions, Symbols and Explanations

The terms, definitions, symbols and explanations established in GB/T 1805 and Table 1 apply to this standard.

Term	Definition or Explanation	Symbol	Unit
Gas Spring	An elastic element composed of a sealed cylinder, a piston that can slide in the cylinder, and a piston rod assembly, using nitrogen or other inert gases as the energy – storage medium
Compression Gas Spring	A gas spring in which the piston rod is in a freely extended state without external force and can withstand pressure
Piston Rod Diameter	The diameter of the piston rod of the gas spring	d	mm
Cylinder Inner Diameter	The inner diameter of the gas spring cylinder	D₁	mm
Cylinder Outer Diameter	The outer diameter of the gas spring cylinder	D₂	mm
Stroke	The axial displacement of the piston rod from the fully extended state to the minimum compressed size	S	mm
Extended Length	The effective length of the gas spring in the fully extended state	L	mm
Start – up Force	The initial force required to press the piston rod after the gas spring has been in the extended state for a certain period	F₀	N
One Cycle	The piston rod is compressed and extended once each according to the specified stroke
Specified Force	The force marked on the drawings and products confirmed by both the supplier and the demander (F, Fa, F₃, …)	Fx	N
Minimum Extension Force	The force measured at the specified force – measuring point C at the starting point of the working stroke during the extension process	F₁	N
Maximum Extension Force	The force measured at the specified force – measuring point C at the end point of the working stroke during the extension process	F₂	N
Minimum Compression Force	The force measured at the specified force – measuring point C at the starting point of the working stroke during the compression process	F₃	N
Maximum Compression Force	The force measured at the specified force – measuring point C at the end point of the working stroke during the compression process	F₄	N
Nominal Force a	F.=(F₁ + F₃)/2. Nominal force a is one of the indicators of the comprehensive characteristics of the gas spring	F.	N
Nominal Force b	F₆=(F₂ + F₄)/2. Nominal force b is generally used for calculating the force ratio	F₆	N
Dynamic Friction Force	F,=(F₃ – F₁)/2	F,	N
Extension Speed	The average speed at which the piston rod freely extends from the end of the specified stroke to the initial position	v	mm/s
Gas Damper Part	The area where the piston movement is affected by gas damping during the extension process of the piston rod		mm
Liquid Damper Part	The area where the piston movement is affected by liquid damping during the extension process of the piston rod		mm
Measuring Point	The point for collecting force values during dynamic or static testing. When S≤80 mm, C = 5 mm; when S>80 mm, C = 10 mm	C	mm
Force Ratio	α = F₆/F.	α