Wax-Compensated Gas Pressure Spring for Stable Force Across Temperature
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Solution Overview
Problem
Conventional gas pressure springs with compensating media like mineral oil or two-phase systems fail to adequately compensate for temperature-dependent spring force variations within the desired operating temperature range, leading to inefficiencies and safety concerns.
Innovation Solution
A gas pressure spring utilizing an expanding wax as a compensating medium, which undergoes phase transitions from solid to liquid with a significant volume increase, thereby compensating for temperature-induced pressure changes and maintaining a consistent spring force across the operating temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mineral oil is used as compensating medium, then the gas pressure spring can compensate for temperature dependency, but the volume expansion is insufficient in the operating temperature range
Solution Approach 1:
The patent changes the physical state parameter of the compensating medium from liquid (mineral oil) to solid-liquid coexisting (wax), which fundamentally alters the thermal expansion characteristics. The wax exhibits solid behavior at lower temperatures and transitions to liquid at higher temperatures, providing significantly greater volume expansion (10-20%) compared to mineral oil, thereby resolving the contradiction between reliability of temperature compensation and quantity of volume expansion
Solution Approach 2:
The patent uses a composite approach by combining wax with a small amount of mineral oil (5-50% by volume). This composite medium leverages the high expansion capability of wax while using the mineral oil to ensure fluidity and proper functioning at all temperatures. The combination achieves both sufficient volume expansion and reliable temperature compensation across the entire operating range
2Quantity of substance
If two-phase systems are used as compensating medium, then high volume expansion is achieved, but the gaseous phase compressibility reduces the effective compensation
Solution Approach 1:
The patent changes the phase state parameter from gas-liquid two-phase to solid-liquid coexisting. By using wax that transitions from solid to liquid, the system achieves high volume expansion similar to two-phase systems but without the harmful compressibility of gases. The solid phase provides structural stability while the liquid phase provides expansion, resolving the contradiction between volume expansion and compensation effectiveness
Solution Approach 2:
The patent replaces complex two-phase gas-liquid systems with a simpler solid-liquid wax system that is easier to contain and control. The wax system is less prone to leakage and phase separation issues, providing more reliable and durable temperature compensation without requiring complex containment systems
3Reliability
If volatile and corrosive compensating media are used, then temperature compensation is achieved, but safety and transport issues arise
Solution Approach 1:
The patent replaces hazardous volatile and corrosive media (such as CO2, NH3, CH3Cl, SO2, SF6) with non-hazardous wax that is non-flammable, non-corrosive, and non-toxic. This substitution eliminates all safety and transport concerns while maintaining effective temperature compensation, directly resolving the contradiction between reliability of compensation and safety
Solution Approach 2:
The patent converts the potential harm of using volatile media into a benefit by selecting wax that is inherently stable and non-hazardous. The solid-liquid nature of wax provides both the desired thermal expansion for compensation and inherent safety, turning what could have been a hazardous system into a safe and reliable one
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The expanding wax effectively compensates for temperature-dependent spring force variations, ensuring a reliable and consistent performance of the gas pressure spring across a wide temperature range, from -40°C to 100°C, while being easy to produce and durable.
Implementation Method 1
utilizing an expanding wax as a compensating medium, which undergoes phase transitions from solid to liquid with a significant volume increase
Implementation Method 2
expanding wax as a compensating medium, which undergoes phase transitions from solid to liquid with a significant volume increase, thereby compensating for temperature-induced pressure changes
Data Source
AI summary
A gas pressure spring is provided including an expanding wax as a compensating medium for reducing a temperature dependency of a spring force of the gas pressure spring in an operating temperature range of the gas pressure spring spanning a minimum temperature of −40° C. to +10° C. up to a maximum temperature of +40° C. to +100° C. The expanding wax includes at least one liquid phase and at least one solid phase in the entire operating temperature range, the expanding wax comprising a number of primary alcohols. Also provided is a drive system for a flap including a gas pressure spring for supporting the flap, and an electromechanical drive for driving the flap.