Three Position Solenoid Mechanical Stop Null Positioning
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Solution Overview
Problem
Existing three-way spool valves with a center null position require continuous electrical signals to maintain position, leading to electrical and thermal loads on the controller and solenoid coil, and rely on variable-force actuators which can be inaccurate due to spring tolerance variations.
Innovation Solution
A three-position fast acting solenoid design that uses a mechanical stop to hold the spool in position, eliminating the need for continuous electrical input to maintain the null position, with the spool being moved by momentary signals and held by magnetism and mechanical stops in each position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous electrical signals are used to maintain spool position, then the spool can be held in position, but electrical and thermal loads increase on the controller and solenoid coil
Solution Approach 1:
The solenoid coil is energized only periodically to move the spool between positions, rather than continuously. Once the spool reaches a desired position, it is held by mechanical stops and spring forces without requiring continuous electrical power, thus reducing thermal and electrical loads while maintaining position reliability
Solution Approach 2:
The patent replaces the continuous electrical holding mechanism with a mechanical holding system consisting of mechanical stops and spring forces. The mechanical stops physically limit spool travel and maintain position, substituting the need for continuous electromagnetic force with passive mechanical elements
2Ease of operation
If variable-force actuators with springs are used to move the spool, then the spool can be actuated, but positioning accuracy decreases due to spring tolerance variations
Solution Approach 1:
The patent introduces mechanical stops as intermediary elements between the spring force and the spool position. The stops act as precise reference points that define the null position independently of spring force variations, allowing the spring to provide actuation force while the stop ensures accurate positioning
Solution Approach 2:
The spool valve is segmented into distinct positional zones defined by mechanical stops. The null position is separated into a specific zone bounded by stops, allowing precise definition of the centered position independent of the continuous variable force from springs
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 design achieves accurate null positioning without electrical input, reducing thermal loads and allowing for smaller, lighter solenoid coils, and is applicable to both two-way and three-way spool valves.
Implementation Method 1
A solenoid coil and first and second flux guides define a space in which an armature can be moved to either a first or second end position by energizing the solenoid coil
Implementation Method 2
The armature is moved to the first end position by applying a first electrical signal to the solenoid coil and to the second end position by applying a second electrical signal to the solenoid coil
Data Source
AI summary
A three position fast acting solenoid which may be coupled to a spool valve with a center null position. The spool of the valve is moved to one of three positions by a momentary signal to either of two coils. The spool is held positively in each end position by magnetism, and in the center position by a mechanical stop, so that the valve requires no electrical input except when the valve is changing from one position to another.