Piston Sealing Device with Extensible Segment for High Pressure
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Solution Overview
Problem
Existing sealing technologies for high-pressure pistons face challenges in achieving tight sealing while minimizing friction losses, as conventional methods either lead to excessive oil leakage or increased friction, material restrictions, and reduced volumetric efficiency under high pressures.
Innovation Solution
A sealing device with a sliding skirt and extensible continuous segments, connected by a mechanical inter-skirt connection, a sliding skirt spring, and a floating plate, which allows for axial compression and radial centering, enabling efficient sealing and minimizing friction losses across varying pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small clearance is provided between the piston and cylinder through precision machining, then sealing is effective at pressures of several tens to hundreds of bars, but under very high pressures (1500-2000 bars) oil leakage rates increase significantly
Solution Approach 1:
The piston body is designed with controlled deformation characteristics that allow it to adapt dynamically to pressure changes. Under high pressure, the piston body deforms to maintain optimal clearance with the cylinder, transitioning from a rigid fixed clearance design to a dynamic adaptive sealing interface that prevents oil leakage at pressures up to 2000 bars
Solution Approach 2:
The invention changes the physical state and geometric parameters of the piston body under pressure. By designing specific deformation zones and rigidity distributions, the piston body's shape and clearance characteristics change in response to pressure, optimizing sealing performance across different operating conditions without requiring precision machining for all pressure ranges
2Reliability
If a seal is housed in a groove on the periphery of the piston, then sealing is provided, but under very high pressures the seal deforms in its groove, exerts high pressure on the cylinder, and generates high friction losses
Solution Approach 1:
The invention extracts and eliminates the traditional groove-housed seal from the piston design. Instead of placing a seal in a groove that causes deformation and high friction under pressure, the design uses the piston body's controlled deformation and surface characteristics to achieve sealing directly, removing the problematic intermediate sealing component
Solution Approach 2:
The piston body itself acts as an intermediary between the fluid pressure and the cylinder wall. Through controlled deformation zones and surface properties, the piston body mediates the sealing function without requiring a separate seal element, thereby eliminating the friction and deformation issues associated with groove-housed seals
3Stress or pressure
If the cylinder diameter is increased to accommodate larger clearance under high pressure, then the piston can operate at higher pressures, but the volumetric efficiency of the oil pump is reduced
Solution Approach 1:
The piston body's controlled deformation creates a dynamic clearance that adapts to pressure changes. Instead of requiring a permanently larger cylinder diameter, the deformation mechanism maintains optimal clearance under high pressure, preserving volumetric efficiency while enabling higher operating pressures
4Reliability
If cup segments are used for sealing, then sealing is provided, but oil leakage rates in the region of the cup are excessive and the cup size increases with cylinder diameter under pressure
Solution Approach 1:
The invention removes the cup segment sealing mechanism entirely from the design. Instead of using cup segments that suffer from excessive leakage and size increases under pressure, the piston body's controlled deformation and surface characteristics provide sealing functionality without these problematic components
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 achieves robust and durable sealing with minimal friction losses even at pressures up to 2000 bars, maintaining mechanical efficiency and volumetric performance without requiring complex processes or expensive materials.
Implementation Method 1
at least one extensible continuous segment of continuous annular form, interposed between the fixed skirt and the sliding skirt... wherein, when the pressure in the fluid chamber is zero, said segment leaves a diametral clearance with the cylinder and has a radial thickness such that, above a certain pressure exerted by the fluid on said segment, said segment comes into contact with the cylinder over all of the circumference thereof
Implementation Method 2
above a certain pressure exerted by the fluid on said segment, said segment comes into contact with the cylinder over all of the circumference thereof
Implementation Method 3
at least one sliding skirt of cylindrical shape housed in the cylinder with a small clearance, placed in the extension of the piston head on the side of the compression face... said sliding skirt being connected to said head by a mechanical inter-skirt connection which enables it to move in longitudinal translation with respect to said head
Data Source
AI summary
The sealing device (1) for a piston (2) of which the fixed skirt (5) moves in a cylinder (8) includes a sliding skirt (6) traversed axially by a pressure transmission channel (10) and connected to the fixed skirt (5) by a mechanical inter-skirt connection (7) whilst an extensible continuous segment (9) is interposed in a sealed manner between the skirts (5, 6) and can come into contact with the cylinder (8) when its internal cylindrical segment face (12) is subjected to the pressure of a fluid (36) via the pressure transmission channel (10), a sliding skirt spring (16) tending to bring the skirts (5, 6) closer and to axially compress the extensible continuous segment (9) between the skirts (5, 6).