Stepped Piston Seal Structure for Wobble-Prone Compressors
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Solution Overview
Problem
Existing compressors, particularly piston compressors in vehicles, suffer from leaks due to wobbling movements between the piston and cylinder, leading to inefficiencies and noise generation, despite attempts to improve sealing mechanisms.
Innovation Solution
A piston design with a profiled annular seal body having circumferentially extending lips and an open profile base, retained between a step-side piston ring and a compression-volume-side retaining ring, ensures pressure-tight sealing between compression volumes, even under high stress and wobbling movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connection between the connecting rod and piston is used, then the structural strength is improved, but leaks occur due to wobbling movement between the piston and cylinder
Solution Approach 1:
The patent applies the dynamics principle by replacing the rigid fixed connection between the piston and connecting rod with a spherical bearing connection that allows controlled wobbling movement. This dynamic connection adapts to the varying forces during compression strokes while maintaining proper sealing contact, resolving the contradiction between structural strength and sealing reliability.
Solution Approach 2:
The patent changes the connection parameter from rigid fixed to spherical bearing allowing angular movement. This parameter change enables the piston to accommodate wobbling movements while maintaining sealing effectiveness, thus resolving the contradiction between structural strength and sealing reliability.
2Reliability
If conventional sealing measures are applied to counteract leaks, then sealing is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the sealing function from complex multi-component sealing mechanisms and concentrates it into a single spherical bearing that inherently maintains sealing contact through its geometric design. This simplifies the sealing mechanism while maintaining reliability.
Solution Approach 2:
The spherical bearing performs self-service by automatically maintaining sealing contact through its geometric configuration and the forces generated during operation. The bearing's spherical geometry ensures continuous contact with the connecting rod, providing self-adjusting sealing without additional complex mechanisms.
3Volume of moving object
If a two-stage compressor with single piston is used to increase compactness, then the volume is reduced, but the sealing requirements and stress on seals increase
Solution Approach 1:
The spherical bearing connection dynamically adapts to the increased stresses from two-stage compression by allowing controlled angular movements. This maintains reliable sealing contact despite the higher forces and more demanding sealing requirements inherent in compact two-stage compressor designs.
Data Source
AI summary
A piston for a compressor has a first end subjectable to pressure and intended to be directed toward a first volume of the compressor, and a second end subjectable to pressure located opposite the first and intended to be directed toward a second volume of the compressor. The first and the second volume are interconnected via a connecting line. The first end is in the form of a full-surface-area full side. The second end is in the form of an annular, stepped side. On the second end, the piston carries a sealing arrangement, which seals the first volume with respect to the second. An annular seal body, in the form of a sealing sleeve, is retained in a pressure-tight manner, via a profile base, on the stepped side, between a step-side piston ring arranged on the second end and a compression-volume-side retaining ring.