Hydropneumatic Piston Accumulator Gas Diffusion
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Solution Overview
Problem
Existing hydropneumatic piston-cylinder arrangements face challenges in compact design for mobile applications, with external gas accumulators increasing installation space requirements and suffering from gas diffusion issues due to membrane permeability, leading to reliability concerns and delayed response behavior.
Innovation Solution
A compact hydropneumatic piston-cylinder arrangement with an integrated piston accumulator and a one-way flow control valve featuring a throttle point, along with a throttle check valve in the intermediate body, ensures reduced space usage and enhanced operational reliability by preventing gas diffusion and allowing adaptive damping characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a bladder accumulator with membrane is used to integrate the pneumatic spring accumulator into the cylinder, then the installation space requirement is reduced, but gas diffusion through the membrane material leads to operational unreliability in long-term operation
Solution Approach 1:
The patent uses a membrane (16) to separate the hydraulic fluid (6) from the compressed gas (7) in the bladder accumulator (5), integrating the pneumatic spring accumulator into the cylinder. This flexible membrane allows compact design while maintaining the functional separation between hydraulic and pneumatic chambers, resolving the space requirement issue.
Solution Approach 2:
The patent applies an amorphous carbon layer (18) coating on the membrane (16) to prevent gas diffusion through the membrane material. This composite structure combines the flexibility and sealing properties of the membrane with the gas barrier properties of the carbon coating, addressing the reliability issue while maintaining compact design.
2Reliability
If external gas accumulators are used with lockable valves and supply/discharge lines, then operational reliability can be maintained, but the installation space requirement increases and response behavior is delayed due to long control paths
Solution Approach 1:
The patent merges the gas accumulator function with the cylinder by integrating the bladder accumulator (5) directly into the cylinder structure. The membrane (16) separates the hydraulic fluid (6) from the compressed gas (7) within the same cylindrical housing, eliminating external accumulators and reducing installation space while maintaining reliability through the integrated design.
Solution Approach 2:
The patent transitions from an external, distributed accumulator system to an internal, integrated bladder accumulator design. By placing the gas accumulation function within the cylinder's radial dimension rather than requiring external axial space, the system achieves compactness without compromising operational reliability.
3Strength
If a piston accumulator is used with the accumulator piston directly adjacent to the hydraulic fluid, then mechanical robustness is improved, but the design complexity increases
Solution Approach 1:
The patent extracts the membrane component from the accumulator design and replaces it with a rigid accumulator piston (19). This piston directly separates the hydraulic fluid (6) from the compressed gas (7) without requiring flexible membrane materials or diffusion barrier coatings, simplifying the design while enhancing mechanical robustness.
Solution Approach 2:
The patent replaces the complex membrane with amorphous carbon coating system with a simpler, more durable piston-based separation mechanism. The accumulator piston (19) provides a reliable, maintenance-free separation between hydraulic and pneumatic chambers, eliminating the need for specialized membrane materials and their associated manufacturing complexity.
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 solution provides a compact, reliable, and adaptable suspension system with reduced vibrations and improved mechanical robustness, ensuring efficient operation in limited spaces with optimized damping and suspension performance.
Implementation Method 1
a one-way flow control valve is provided with a valve plate in which there is a bore to form a throttle point
Implementation Method 2
an intermediate body is arranged axially fixed to the accumulator piston, in which at least one fluid passage enabling a predetermined throughflow is provided
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a hydropneumatic piston/cylinder arrangement, in particular for use as a spring element and/or shock absorber element, comprising a cylinder (1) and a piston (15) which is axially movable in the cylinder chamber (5) of said cylinder, the cylinder chamber being filled with hydraulic fluid. The piston (15) is connected to a piston rod (13) which extends outwards in a sealed manner from one end of the cylinder (1), and the base of said piston, which is remote from the piston rod (13), can be operatively connected to a pneumatic spring mechanism (7) in order to convey fluid. Said piston/cylinder arrangement is characterised in that a piston accumulator (7), the accumulator piston (19) of which directly adjoins the hydraulic fluid situated in the cylinder chamber (5), is provided as the spring mechanism.