Multistage Piston Actuator Axial Length Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multistage piston actuators are complex in structure, difficult to modify in terms of piston stages, and challenging to miniaturize or reduce in axial length while maintaining a sufficient effective pressure-receiving area within a specified outer diameter.
Innovation Solution
A multistage piston actuator design featuring a cylinder body with piston bodies and partitions, where each piston body includes a pressure receiving plate and a slidable cylindrical guide, and partitions have a large-diameter outermost cylindrical portion and a small-diameter slidable guide, with overlapping O-rings for sealing, allowing for easy adjustment of piston stages and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional multistage piston actuators are designed with multiple piston stages, then the driving force is increased, but the structural complexity increases and the axial length increases
Solution Approach 1:
The actuator is divided into multiple independent piston stages, each with its own piston body and pressure chamber. These segmented stages are stacked axially, allowing the driving force to be increased by simply adding or removing stages without complicating the overall structure. Each stage operates independently but contributes to the total driving force through the common push rod mechanism.
Solution Approach 2:
The piston bodies are nested within the cylinder body in a compact axial arrangement, with each piston stage contained within the same cylindrical envelope. This nesting approach allows multiple piston stages to be accommodated within a limited axial space, increasing driving force without proportionally increasing the overall actuator size or structural complexity.
2Force
If the number of piston stages is increased to obtain greater driving force, then the effective pressure-receiving area is increased, but the axial length of the actuator increases
Solution Approach 1:
Instead of increasing the diameter of individual piston stages to increase the pressure-receiving area, the design stacks multiple piston stages axially, utilizing the axial dimension to accumulate effective area. This allows the total pressure-receiving area to be increased without increasing the outer diameter, thereby maintaining a compact axial length while achieving greater driving force.
Solution Approach 2:
Multiple piston stages are merged into a single integrated actuator structure, sharing common components such as the cylinder body, push rod, and sealing mechanisms. This merging approach allows the effective pressure-receiving areas of all stages to be summed while avoiding the need for separate actuators, thereby increasing the total driving force without proportionally increasing the axial length.
3Reliability
If conventional designs use multiple sealing mechanisms for each piston stage, then the sealing reliability is improved, but the manufacturing complexity and assembly difficulty increase
Solution Approach 1:
The sealing components are designed to serve multiple functions and multiple piston stages simultaneously. For example, the piston rods serve both as structural support elements and as sealing surfaces, while the O-rings provide sealing for both the pressure chambers and the guide portions. This multi-functionality reduces the number of dedicated sealing components needed, simplifying manufacturing and assembly while maintaining sealing reliability.
Solution Approach 2:
The same sealing components (O-rings) and sealing approaches are used consistently across all piston stages, creating a homogeneous sealing system. This standardization allows for simplified manufacturing processes, easier assembly, and reduced inventory requirements, while maintaining uniform sealing reliability across all stages. The repetitive use of identical sealing elements throughout the actuator reduces complexity compared to using different sealing mechanisms for each stage.
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
The design results in a simpler, more adaptable actuator that can be miniaturized and reduced in axial length while maintaining a larger effective pressure-receiving area, facilitating easier assembly and operation.
Implementation Method 1
compressed air is supplied to an axial air passage formed in the axial rod, and the compressed air is communicated to pressure chambers of the piston bodies through the axial air passage
Implementation Method 2
a large-diameter sealing member (O-ring) to be inserted in between an inner peripheral surface of the large-diameter outermost cylindrical portion and the base plate portion of the partition and the pressure receiving plate portion and an outer peripheral surface of the slidable cylindrical guide portion of the piston body
Data Source
AI summary
A multistage piston actuator exerts a driving pressure against a spring pressure into pressure chambers of piston bodies, fitted into a cylinder body, to operate the push rod. Each piston body is combined with a partition fitted into the cylinder body. Each piston body includes a pressure receiving plate portion, and an axial rod and a slidable cylindrical guide portion extending concentrically in opposite directions, the axial rod having an axial air passage connected to the pressure chambers. Each partition includes a base plate portion having a through-hole which receives the axial rod of an adjacent piston body, a large-diameter outermost cylindrical portion fitted into the cylinder body, and a slidable cylindrical guide portion slidably fit-engaged with the slidable cylindrical guide portion of the piston body. The axial rods of each piston body are brought into contact to operate the push rod.