Servo Valve Magnetic Spring Stabilization
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Solution Overview
Problem
Existing servo valves face instability and positioning issues due to varying spring forces and backlash, leading to unreliable valve states during power failures or vibrations, and require high motor thrust to overcome initial loads, making precise control challenging.
Innovation Solution
A servo valve design incorporating a first and second elastic portion with opposing forces, a connecting portion, and a drive unit with a magnetic body, allowing for balanced elastic forces to stabilize the movable element at the neutral position and enable precise control through adjustable restoring forces, regardless of the movable element's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical springs are used to return the movable element to the neutral position, then the movable element can be restored to neutral, but the restoring force becomes small in the vicinity of the neutral position causing unstable positioning
Solution Approach 1:
The patent changes the parameter of the restoring force characteristic by using a magnetic spring instead of a mechanical spring. The magnetic spring provides a restoring force that remains sufficiently large even in the vicinity of the neutral position, unlike mechanical springs whose force approaches zero near the neutral position. This parameter change resolves the contradiction by maintaining both reliability of positioning and adequate restoring force.
Solution Approach 2:
The patent replaces the mechanical spring system with a magnetic field-based system (magnetic spring). This substitution eliminates the fundamental limitation of mechanical springs where the restoring force becomes negligible near the neutral position. The magnetic spring maintains a consistent restoring force characteristic across the entire range of motion, including the critical neutral position vicinity, thereby achieving stable positioning.
2Reliability
If mechanical springs are used for returning the movable element, then restoration to neutral is achieved, but backlash and looseness make positioning control and opening-degree control difficult
Solution Approach 1:
The patent replaces the mechanical spring connection with a magnetic field-based connection. This substitution eliminates mechanical backlash and looseness that inherently plague mechanical spring systems. The magnetic spring provides a continuous, backlash-free restoring force that enables precise positioning control and accurate opening-degree control of the movable element, thereby improving control precision without sacrificing reliability.
3Ease of operation
If a motor with large thrust force is used to overcome the initial load of the mechanical spring, then the movable element can be moved, but positioning control and opening-degree control become difficult due to spring force variation
Solution Approach 1:
The patent changes the force characteristic parameter from a mechanical spring (where force varies with displacement) to a magnetic spring (where force can be maintained more consistently). This allows the drive unit to operate with more uniform conditions throughout the range of motion, improving positioning control precision while maintaining ease of actuation. The magnetic spring's force characteristic can be optimized to provide consistent restoring force regardless of position.
Solution Approach 2:
By replacing the mechanical spring system with a magnetic spring system, the patent eliminates the position-dependent force variation inherent in mechanical springs. This substitution creates a more predictable and controllable force environment, allowing for precise positioning control and accurate opening-degree control without requiring excessive thrust force from the drive unit.
4Device complexity
If no restoring force mechanism is used (Document 1), then the structure is simple, but the movable element position is not fixed during power failure causing valve opened state
Solution Approach 1:
The patent introduces a magnetic spring to provide a restoring force mechanism while maintaining relative structural simplicity. The magnetic spring replaces the need for complex mechanical spring assemblies and their associated mounting hardware. By using magnetic fields to provide the restoring force, the patent achieves both reliability (fixed movable element position during power failure) and structural simplicity, as the magnetic spring can be integrated into the existing valve structure with minimal additional components.
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 stabilizes the movable element's positioning, ensuring reliable valve states and improved controllability, reducing the need for high motor thrust and enhancing responsiveness to input signals, while maintaining consistent restoring forces.
Implementation Method 1
a drive unit connected to the body in the axial direction and configured to slide the movable element in the axial direction
Implementation Method 2
a first elastic portion extending in the axial direction inside the body and having a first elastic force to press the movable element toward the drive unit side in the axial direction, and a second elastic portion extending in the axial direction inside the body and having a second elastic force to press the movable element in a direction away from the drive unit along the axial direction
Data Source
AI summary
A servo valve has a movable element disposed inside a body, and a drive unit to slide the movable element in the axial direction. A first elastic portion on one end portion side of the body has a first elastic force to press the movable element toward the drive unit connected to another end portion of the body; a second elastic portion on another end portion side of the body has a second elastic force to press the movable element toward the one end portion side of the body. A connecting portion is connected to the second elastic portion, wherein at a neutral position of the movable element, the connecting portion abuts against an inner peripheral surface of the body and against the movable element. An end of one of the first and second elastic portions is fixed directly to the movable element, and an end of the other of the first and second elastic portions is connected to the connecting portion.