Hydraulic Actuator Spool Valve Adjustment for Thermal Synchrony
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Solution Overview
Problem
Duplex hydraulic actuator systems experience 'force fight' due to asynchronous actuation of spool valves, leading to increased pressure and potential damage, which is exacerbated by manufacturing tolerances and thermal effects, necessitating strong and heavy components to compensate.
Innovation Solution
The introduction of an adjustment device utilizing a shape memory alloy (SMA) and a spring mechanism to dynamically adjust the pivot point of the summing lever, compensating for thermal expansion and maintaining synchrony between spool valves, thereby preventing force fight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spool valves are actuated simultaneously to prevent force fight, then system reliability is improved, but manufacturing precision requirements increase due to tolerances affecting synchronization
Solution Approach 1:
The patent replaces the purely mechanical linkage system with a hybrid system incorporating shape memory alloy (SMA) actuators. These SMA actuators sense temperature changes and automatically adjust the summing lever pivot point position, compensating for thermal expansion effects that would otherwise cause desynchronization between spool valves. This substitution of mechanical adjustment with thermally-responsive material behavior resolves the contradiction by making the system self-compensating.
Solution Approach 2:
The invention changes the physical parameter of the summing lever pivot point position dynamically in response to temperature changes. By using shape memory alloys that undergo phase transformation at specific temperatures, the system automatically adjusts geometric parameters (lever arm lengths) to maintain synchronization. This parameter change approach allows the system to adapt to thermal effects without requiring tighter manufacturing tolerances.
2Strength
If strong and heavy components are used to compensate for force fight, then strength is improved, but weight increases
Solution Approach 1:
The shape memory alloy actuators perform preliminary action by preemptively adjusting the summing lever pivot point position in response to temperature changes before force fight can occur. This preventive adjustment ensures that both spool valves remain synchronized even under thermal expansion conditions, eliminating the need for oversized components designed to withstand force fight loads. The system proactively prevents the problem rather than reactively compensating for it.
3Manufacturing precision
If manufacturing tolerances are tightened to improve synchronization, then synchrony between spool valves is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The shape memory alloy acts as an intermediary element between the thermal environment and the summing lever mechanism. Rather than relying on tight manufacturing tolerances to directly ensure synchronization, the SMA mediates thermal effects by automatically adjusting pivot point positions. This intermediary mechanism transforms thermal input into beneficial geometric adjustment, simplifying manufacturing requirements while maintaining synchrony.
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 solution reduces thermally-induced force fight, allowing for the use of lighter materials in spool valves and associated components, potentially leading to weight savings and improved system reliability.
Implementation Method 1
a first adjustment device (100) provided in the first hydraulic system (10) to compensate for thermal expansion of a body (20) of the first spool valve (20) using a shape memory alloy (SMA)
Implementation Method 2
to compensate for thermal expansion of a body (20) of the first spool valve (20)
Implementation Method 3
utilizing a shape memory alloy (SMA) and a spring mechanism to dynamically adjust the pivot point of the summing lever
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present disclosure relates to an adjustment system a method for compensating for temperature variations in a spool valve. The spool valve and adjustment system may be parts in a duplex hydraulic actuator. The adjustment device comprises a spring, a pivot point, and a shape memory alloy (SMA) device. The spring and SMA device are disposed on either side of the pivot point to hold the pivot point in a first position. The SMA device is configured to change size in response to a temperature change so as move the pivot point to a second location. This may eliminate force fight in the duplex hydraulic actuator by preventing asynchronous activation of the spool valves due to thermal expansion within the spool valves.