Piezo Valve Lever Geometry for Stable Displacement Control
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Solution Overview
Problem
Conventional fluid control valves using piezo stacks suffer from deteriorated reproducibility of displacement amount due to lateral displacement of the pressing plate body, leading to issues with position stability, liquid leakage, and controllability.
Innovation Solution
A fluid control valve with a displacement expanding mechanism featuring lever members around a central axis, where the contact surfaces form a downward gradient, ensuring the input member is less likely to be displaced laterally, and includes line contact pressing portions to enhance mechanical strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pressing plate body with a flat lower surface is used to contact the lever body, then the结构简单性 (structural simplicity) is improved, but the position stability deteriorates due to lateral displacement
Solution Approach 1:
The lower surface of the pressing plate body is changed from a flat surface to a convex curved surface that contacts the distal end of the lever body. This curvature modification prevents lateral displacement while maintaining structural simplicity, as the convex shape naturally guides the lever body to remain centered on the pressing plate during actuation.
2Ease of operation
If the lower end of the piezo stack is left as a free end for displacement, then the actuator functionality is improved, but the reproducibility deteriorates due to lateral displacement of the pressing plate body
Solution Approach 1:
The convex curved lower surface of the pressing plate body ensures that the lever body consistently contacts the highest point of the curve, providing reproducible displacement transmission while allowing the piezo stack's free end to maintain its actuator functionality.
Solution Approach 2:
Instead of trying to constrain the lever body to prevent lateral displacement, the design inverts the approach by making the pressing plate's contact surface convex, which passively guides the lever body to remain centered through the geometry of the contact interface.
3Force
If a convex distal end of the lever body is used to contact the pressing plate body, then the force transmission is improved, but the position stability deteriorates due to lateral displacement
Solution Approach 1:
The convex curved lower surface of the pressing plate body works in conjunction with the convex distal end of the lever body to create a point contact that naturally resists lateral displacement while maintaining effective force transmission along the central axis.
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
Improves position stability and reproducibility of displacement, reducing liquid leakage and maintaining controllability by enhancing the responsiveness of fluid control.
Implementation Method 1
a fluid control valve that uses a piezo stack as an actuator for driving a valve body
Data Source
AI summary
A fluid control valve improves position stability of a displacement expanding mechanism, and includes an actuator for driving the valve body, and the displacement expanding mechanism interposed between the valve body and the actuator to expand displacement of the actuator and transmit the displacement to the valve body. The displacement expanding mechanism includes an input member that is displaced upon receiving a driving force from the actuator, and a plurality of lever members that are disposed around a central axis of the valve body between the input member and the valve body, and expand displacement of the input member and transmit the displacement to the valve body. The plurality of lever members each have a contact surface with which the input member comes into contact to serve as a force point portion. The contact surface forms a downward gradient toward the central axis of the valve body.