Normally High Solenoid via Sleeve Inversion
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Solution Overview
Problem
There is a need for a solenoid assembly that functions like a normally high solenoid but with the packaging space and cost efficiency of a normally low solenoid, as normally high solenoids are typically more expensive and larger in size.
Innovation Solution
A linear force solenoid assembly is designed with a bushing or sleeve having slots aligned with ports in a valve body, featuring a movable spool valve and armature that biases to a default open position when de-energized, allowing pressurized hydraulic fluid to flow, utilizing a spring and magnetic field to control fluid flow between ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a normally high solenoid is used to ensure hydraulic fluid flow during electrical failure, then reliability is improved, but packaging space and cost increase
Solution Approach 1:
The patent inverts the traditional normally high solenoid design by creating a normally low solenoid configuration where the valve defaults to closed position. The sleeve is positioned to block fluid flow when de-energized, and the solenoid opens the flow path when energized. This inversion achieves normally high functionality (flow assurance during failure) using a compact normally low solenoid structure, resolving the contradiction between reliability and size.
2Reliability
If a normally high solenoid is used to ensure hydraulic fluid flow during electrical failure, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies the inversion principle to use a standard normally low solenoid design instead of a specialized normally high solenoid. By positioning the sleeve to block flow in the de-energized state and using the solenoid to open the path when energized, the system achieves fail-safe flow assurance using conventional, lower-cost normally low solenoid manufacturing processes and components.
3Reliability
If a linear force solenoid with spring bias is used to maintain valve position, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent employs a spring-loaded mechanism where the spring automatically biases the valve to the closed position when the solenoid is de-energized. This self-service approach uses the spring's inherent elastic force to maintain reliable valve positioning without requiring additional actuators, sensors, or complex control systems, thus improving reliability while minimizing added complexity.
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 solenoid assembly effectively acts as a normally high solenoid, ensuring hydraulic fluid flow to transmission components while reducing size and cost, maintaining fluid communication without sticking issues due to maintained axial distances between valve components.
Implementation Method 1
A solenoid has a movable armature configured to move the valve
Implementation Method 2
a spring is disposed in the bore and is in contact with the valve to bias the valve to the first position
Implementation Method 3
The hydraulic control system is provided pressurized hydraulic fluid from a pump
Data Source
AI summary
A solenoid assembly is disposed in a bore of a valve body where the bore includes a plurality of ports. The solenoid assembly includes a bushing or sleeve disposed in the bore. The sleeve has at least one slot that is aligned with at least one of the plurality of ports. A valve is slidably disposed within the sleeve. A solenoid has a movable armature configured to move the valve.