Hydraulic Accumulator Bellows Guide Mechanism
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Solution Overview
Problem
Existing hydraulic accumulators with metal bellows face challenges in ensuring safe guidance and preventing folds compression during contraction, particularly in applications with high-frequency and high-acceleration movements, where the service life and operational reliability are compromised by complex and expensive guide mechanisms.
Innovation Solution
A hydraulic accumulator design where the bellows end is fixed to a retaining ring on the housing, and the guide mechanism includes an annular body engaging in a peripheral groove, forming a form-fitting stroke limiter and external guide, with a second ring groove for enhanced tilt-proof guidance, utilizing plastic ring bodies with good sliding properties for reduced friction and simplified production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual guide bodies are attached to the peripheral edge of the bellows end body, then good guiding properties and safe long-term operation are achieved, but production becomes complicated and expensive
Solution Approach 1:
The guide bodies are merged with the annular body to form an integrated guide means. The annular body includes guide surfaces that directly engage with the housing wall, eliminating the need for separate attached guide bodies. This integration simplifies production while maintaining reliable guidance of the bellows end body along the housing wall.
Solution Approach 2:
The annular body serves multiple functions: it provides structural support for the bellows end body, forms guide surfaces for sliding along the housing wall, and creates fluid passages between its guide surfaces and the housing wall. This multi-functionality reduces the number of separate components needed while ensuring reliable operation.
2Adaptability or versatility
If the bellows is allowed to contract freely, then the accumulator can accommodate pressure variations, but folds may be compressed reducing service life
Solution Approach 1:
The stroke limiting means is positioned to prevent excessive contraction of the bellows before folds compression can occur. The sleeve extending from the end body engages with a stop on the housing to limit the contraction stroke, ensuring the bellows folds never reach a compressed state that would damage them, while still allowing sufficient contraction for pressure accommodation.
Solution Approach 2:
The sleeve acts as an intermediary element between the bellows end body and the housing stop. It provides a controlled interface that limits the contraction movement, protecting the bellows folds from compression damage while maintaining the pressure accommodation functionality of the accumulator.
3Strength
If a retaining ring is used to fix the bellows end, then the bellows can be securely mounted, but the structure becomes more complex
Solution Approach 1:
The retaining ring function is merged with the annular body. The annular body is fixed to the bellows end body and provides both structural retention and guidance functions in one component, eliminating the need for a separate retaining ring while maintaining secure mounting of the bellows to the housing.
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 ensures increased operational reliability and stable guidance, preventing fold compression and improving the service life of the bellows by providing a safe and efficient stroke limitation and tilt-proof guidance, while maintaining low frictional forces and cost-effectiveness.
Implementation Method 1
a metal bellows (19), which has been provided with a guide means (47, 55), for separating a gas space (21) and a fluid space (23)
Implementation Method 2
made of a plastic material with good sliding properties, good guide properties are achieved, i.e. the guide enables safe long-term operation with favorable friction conditions between the guide body and the housing wall
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A hydraulic accumulator, especially a pulsation damper, comprises a metal bellows (19) that has a terminal element (35) which can be displaced along the wall of a housing (1) at least on one bellows end (31) during expansion and compression of the bellows (19), a guiding means (47) being interposed between the terminal element and the housing (1). Said guiding means comprises, on at least one peripheral zone of the terminal element (35), on its outer periphery, first annular sections (51) that are radially spaced apart from the wall of the housing (1) and that are separated from each other by second annular sections (53) that radially project over the first annular sections (51). The terminal element (35) is axially elongated by a peripheral sleeve part (63) which extends towards the immobile bellows end (29), the end of the sleeve part (63) resting as a stop element on a part (25) which is fixed to the housing when the bellows (19) is compressed. The accumulator is characterized in that the bellows (19), on the end of the bellows (29) opposite the mobile terminal element (35), is immobilized on a retaining ring (25) which is fixed to the housing, the end of the sleeve part (63) abutting on said end. The guiding means comprises an annular element (47) an annular part (49) thereof forming the first annular section (51) engaging in a peripheral groove (45) on the terminal element (35). The annular groove is positioned axially off-set on the terminal element (35) away from the immobile bellows end (29) in the direction increasing the distance to the retaining ring (25).