Cylinder Apparatus Two-Stage Sealing High Pressure
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Solution Overview
Problem
Existing cylinder apparatuses for automobile suspension systems face challenges in achieving high pressure resistance at the open end, particularly when subjected to high hydraulic pressures, due to the inferior productivity of threaded cap closures and the limited durability of staked or caulked portions.
Innovation Solution
A cylinder apparatus design featuring an outer tube with a hydraulic fluid seal, a piston, and annular seals secured by staked or caulked portions, which reduce the pressure acting on the seals through a two-stage sealing mechanism, enhancing pressure resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap is threaded onto the open end of the cylinder, then the open end is closed securely, but productivity is inferior
Solution Approach 1:
The patent replaces the threaded cap closure system with a staking or caulking system. Instead of using threads and caps, the invention uses a staking or caulking tool to deform the outer tube material radially inward, forming a closed end that secures seals through mechanical deformation rather than threaded fastening. This substitution eliminates the need for threading operations and cap installation, thereby improving productivity while maintaining closure security.
2Productivity
If staking or caulking is used to close the open end of the cylinder, then productivity is improved, but pressure resistance is insufficient under high hydraulic pressure
Solution Approach 1:
The patent applies local quality by creating a localized reinforced structure at the closed end of the cylinder. The staking or caulking process deforms the outer tube material radially inward at the closed end, creating a locally strengthened region with increased wall thickness and enhanced structural integrity. This localized reinforcement provides sufficient pressure resistance to withstand high hydraulic pressures while maintaining the productivity benefits of the staking or caulking method.
3Productivity
If the seal case and oil seal are secured by staking or caulking, then productivity is improved, but the staked or caulked portion is subjected to great force under high pressure
Solution Approach 1:
The patent applies preliminary action by performing the staking or caulking operation on the outer tube material before inserting the seal case and oil seal. The outer tube end is pre-deformed radially inward to create a reinforced structure that will subsequently secure the seals. This preliminary reinforcement ensures that when the seal case and oil seal are installed, they are secured by a pre-strengthened structure capable of withstanding high pressure forces, thereby maintaining both productivity and securing strength.
Data Source
AI summary
A piston connected with a piston rod is fitted in an outer tube having a hydraulic fluid sealed therein, with the piston rod projecting out of the outer tube. A seal part for the piston rod includes a rod guide, a seal case, an oil seal, a dust seal and a securing member, which are inserted into an end portion of the outer tube and secured by first and second staked portions. The sliding part of the piston rod is sealed with the rod seal and a seal lip of the oil seal. The area between the seal case and the outer tube is sealed with an O-ring and a seal member. The pressure resistance of the seal part can be increased to a considerable extent by two-point staking by the first and second staked portions and two-stage sealing by the rod seal and the oil seal.