Segmented Piston Hydraulic Actuator Fatigue Resistance
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Solution Overview
Problem
Existing hydraulic actuators face reliability and lifespan issues due to weaknesses in threaded union portions, which can lead to fatigue and require additional mechanical fixings that further affect fatigue resistance.
Innovation Solution
A hydraulic actuator design featuring a piston composed of multiple segments assembled around a piston rod within a chamber, eliminating the need for threaded unions, with a softer material support ring for wear reduction and enhanced sealing, allowing for improved fatigue resistance and unitary construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If threaded unions are used to connect piston to chamber and piston rod, then assembly is enabled, but fatigue resistance deteriorates
Solution Approach 1:
The piston is divided into multiple segments that can be assembled around the piston rod through a access port. This segmentation allows the piston to be installed without threaded unions, eliminating the weak points that cause fatigue while maintaining assembly capability. The segments are held together by a retaining ring, creating a unified piston structure that avoids threaded connections to the chamber and rod.
2Stability of the object's composition
If mechanical fixings are added to lock screw threads, then relative rotation is prevented, but fatigue resistance further deteriorates
Solution Approach 1:
The invention extracts and removes the threaded union portions from the actuator design. By using a piston made of segments that assemble around the rod and are retained by a ring, the design eliminates the need for mechanical fixings to lock screw threads. This removal of threaded connections and their associated locking mechanisms directly improves fatigue resistance while maintaining the necessary stability through the retaining ring structure.
3Reliability
If piston is made from multiple segments, then threaded unions are eliminated, but device complexity increases
Solution Approach 1:
The piston segments are designed to nest around the piston rod in a concentric arrangement. The segments fit together radially, with each segment having a circumferential profile that conforms to the rod's groove. This nesting approach allows multiple segments to be assembled in a compact, organized manner that reduces structural complexity compared to traditional threaded unions, while maintaining the reliability benefits of eliminating threaded connections.
Data Source
AI summary
A hydraulic actuator having a body defining a chamber, a piston rod including an annular groove and a piston head slidably housed within the chamber, the piston head having a number of segments each of which has a base portion mounted within the annular groove.