Gas Spring Temperature Compensation Cup Piston
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Solution Overview
Problem
Conventional gas springs face challenges in effectively compensating for temperature-dependent characteristics due to unsatisfactory volumetric expansion of commonly used compensating media within the operating temperature and pressure range, leading to inefficient temperature compensation and complex structures.
Innovation Solution
Selecting a compensating medium with a critical temperature between the operating temperature range's limits, using a single cup-shaped compensating piston that delimits both the compensating and working chambers, and ensuring the pressure and volume dimensions are matched to prevent transition to a liquid/gas two-phase condition, allowing for reliable temperature compensation without increasing the gas spring's size or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional compensating media (mineral oil, two-phase systems) are used, then the gas spring structure is established, but the volumetric expansion is insufficient within the operating temperature and pressure range
Solution Approach 1:
The patent changes the physical-chemical parameters of the compensating medium by selecting substances with specific critical temperatures within the operating range (−30°C to +80°C). This enables the medium to exhibit significant volumetric expansion through phase transition behavior while maintaining adaptability to temperature variations, directly resolving the contradiction between expansion quantity and temperature compensation effectiveness.
Solution Approach 2:
The patent employs composite compensating media consisting of multiple substances (e.g., CO2 mixed with other gases or liquids) to achieve optimal volumetric expansion characteristics. This composite approach allows tailoring the expansion properties to match the specific operating conditions, improving both the quantity of expansion and the effectiveness of temperature compensation.
2Device complexity
If a single cup-shaped compensating piston is used to delimit both compensating and working chambers, then the device complexity is reduced, but the reliability of temperature compensation must be maintained
Solution Approach 1:
The single cup-shaped compensating piston is designed to perform multiple functions simultaneously: it delimits the compensating chamber, delimits the working chamber, and provides the sealing interface. This multi-functional design reduces the number of components while maintaining reliable temperature compensation through proper dimensional matching and pressure-volume relationships.
Solution Approach 2:
The patent merges the functions of separate compensating and working chamber delimitation into a single integrated compensating piston structure. By combining these functions and properly dimensioning the chamber volumes and pressures, the system achieves reliable temperature compensation with reduced complexity.
3Quantity of substance
If compensating medium with critical temperature within operating range is selected, then volumetric expansion is enhanced, but transition to liquid/gas two-phase condition must be prevented
Solution Approach 1:
The patent carefully selects and controls the pressure and temperature parameters of the compensating medium to maintain it in a stable single-phase state despite using substances with critical temperatures within the operating range. By operating at pressures above the critical pressure, the medium maintains liquid-like density and stability while still providing enhanced volumetric expansion through thermal effects.
Solution Approach 2:
The patent replaces reliance on mechanical phase separation mechanisms with a thermodynamically controlled single-phase system. By selecting compensating media and operating conditions that maintain supercritical or single-phase states, the system achieves stable composition while retaining enhanced volumetric expansion characteristics.
4Reliability
If dimensioning and matching of surfaces, volumes, and restoring force are optimized, then temperature compensation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter relationships and matching criteria for the compensating chamber volume, working chamber volume, piston surface areas, and restoring forces. By defining these parameters with appropriate tolerances and relationships, the system achieves reliable temperature compensation while maintaining feasible manufacturing precision requirements through proper parameter selection and matching.
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
This approach provides improved temperature compensation with a simpler design, utilizing substances like carbon dioxide for enhanced volumetric expansion, reducing the number of parts and overall size, while maintaining effective displacement and stability within the operating conditions.
Implementation Method 1
the compensating medium, which is provided in a compensating chamber and expands if the temperature rises such that the volume of the working chamber increases
Implementation Method 2
the compensating piston arrangement is acted upon by the pressure of the working medium and the pressure of a compensating medium
Implementation Method 3
a restoring medium, which is provided in a restoring chamber such that the volume of the working chamber decreases
Data Source
AI summary
The invention relates to a gas spring which uses a compensating medium acting on a compensating piston in order to compensate the dependence on temperature of its characteristic. According to a first aspect of the invention, a compensating medium (16M) is selected whereof the critical temperature (TK) is between the lower limit temperature (Tlower) and a temperature exceeding the upper limit temperature (Tupper) Of the range of operating temperatures of the gas spring (50) by up to 100° C., and the gas spring (50) is designed such that, at an operating temperature (TB) of the gas spring (50) not exceeding the critical temperature (TK) of the compensating medium (16M), the point indicating the state of the compensating medium (16M) lies on or above the vapor pressure curve. According to a second aspect, in order to simplify the structure of the gas spring (50), a single compensating piston (10) which takes the shape of a cup is used and separates the working chamber (Ia), the compensating chamber (16) and the restoring chamber (15) of the gas spring (50) from one another.