Bellows Accumulator Geometry for Vibration-Resistant Durability
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Solution Overview
Problem
The bellows in hydraulic accumulators easily vibrate and suffer reduced durability due to external vibrations, causing increased amplitude of vibration at the expansion and contraction direction, which leads to contact with the housing inner wall, thereby reducing the service life.
Innovation Solution
The accumulator design includes a bellows with outer and inner annular ridge portions divided into sectors, where the first sector has a smaller diameter than the second sector, positioned between the fixed end and the center, or the inner annular ridge portions have larger diameters in specific sectors to avoid contact with the housing or stay, thereby reducing vibration amplitude and extending the bellows' service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the bellows body has a repetitive structure of outer annular ridge portions and inner annular ridge portions to enable expansion and contraction, then the bellows can perform pressure accumulation and pulsation damping operations, but the bellows easily vibrates against external vibration and the vibration amplitude increases away from the fixed end, causing the bellows to abut on the housing inner wall and reducing durability
Solution Approach 1:
The patent applies local quality by making the outer diameter of outer annular ridge portions vary along the expansion and contraction direction. Specifically, the bellows body has a first region with a smaller outer diameter and a second region with a larger outer diameter. This local variation in geometry allows the bellows to have reduced vibration amplitude in the first region (avoiding contact with the housing) while maintaining adequate expansion capability in the second region, thus resolving the contradiction between operational versatility and durability.
2Power
If the bellows expands and contracts freely to balance gas pressure and liquid pressure, then the pressure accumulation operation is achieved, but the sector where amplitude of vibration away from the fixed end is increased abuts on the inner wall of the housing, reducing the service life of the bellows
Solution Approach 1:
The patent implements local quality by creating distinct regions along the bellows body with different outer diameters. The first region has a smaller outer diameter that reduces vibration amplitude to prevent contact with the housing inner wall, thereby extending service life. The second region has a larger outer diameter that maintains sufficient expansion capability for effective pressure accumulation and pulsation damping operations.
3Ease of manufacture
If the outer annular ridge portions have uniform outer diameter to simplify manufacturing, then the manufacturing process is easier, but the bellows cannot avoid contact with the housing inner wall during vibration, reducing reliability
Solution Approach 1:
The patent applies local quality by introducing a non-uniform outer diameter configuration along the bellows body length. The bellows has a first region with smaller outer diameter and a second region with larger outer diameter. This design requires more complex manufacturing processes but significantly improves reliability by reducing vibration-induced contact with the housing, thereby extending the bellows service life.
Solution Approach 2:
The patent segments the bellows body into distinct regions (first region with smaller diameter, second region with larger diameter) along its length. This segmentation allows different portions of the bellows to serve different functions: the first region minimizes vibration contact while the second region maintains expansion capability, thus improving overall durability without compromising operational performance.
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 design effectively reduces the bellows' contact with the housing or stay during vibrations, prolonging its service life by minimizing the impact of resonance-induced vibrations and maintaining the accumulator's operational efficiency without additional components or structural changes.
Implementation Method 1
the bellows body has a repetitive structure of outer annular ridge portions and inner annular ridge portions by continuously forming ridge-folds and valley-folds in an up and down direction from a metallic film or plate material, the bellows body expands and contracts when the bellows cap moves such that gas pressure in the gas chamber and liquid pressure in the liquid chamber are balanced
Implementation Method 2
by distributing the first sector where the outer diameter of the outer annular ridge portions of the bellows is small in accordance with a sector where amplitude of vibration in a radial direction is locally increased, the bellows can be avoided from abutting on an inner wall surface of the housing
Data Source
AI summary
An accumulator includes a bellows 3 having a plurality of outer ridge portions and a plurality of inner annular ridge portions and configured to be capable of expanding and contracting, and a housing having a fluid supply port and fixed to one end of the bellows serving as a fixed end. An interior of the housing is partitioned in a sealed state into an inside and an outside of the bellows. The outer annular ridge portions are divided into at least a first sector and a second sector which are distributed in an expansion and contraction direction of the bellows such that the second sector is positioned between the first sector and the fixed end. The outer annular ridge portions included in the first sector have an outer diameter smaller than an outer diameter of the outer annular ridge portions included in the second sector.