Linear Solenoid Valve Foreign Substance Removal
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Solution Overview
Problem
Existing linear solenoid valves in hydraulic control circuits face issues with foreign substances like sludge depositing inside pressure adjusting ports, inhibiting spool movement and oil pressure adjustment, requiring a quick and effective foreign substance removal operation without affecting output pressure.
Innovation Solution
A linear solenoid valve with a control part that includes a determination unit for initiating foreign substance removal, a command value setting unit for adjusting current to the coil, and a dither current setting unit that changes the frequency of the dither current to a lower oscillation frequency, increasing the spool's moving force and allowing for more effective removal of deposited substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of oil discharged from the drain port is increased to remove foreign substances, then the foreign substances can be discharged more effectively, but the output pressure is largely lowered
Solution Approach 1:
The patent applies dynamics by making the spool movable and controllable through coil current to dynamically adjust the opening amount of the pressure adjusting port. The spool can be positioned at different locations along the axis to create different opening amounts, allowing the system to transition between normal operation mode and foreign substance removal mode as needed.
Solution Approach 2:
The patent changes the opening amount parameter of the pressure adjusting port by controlling the spool position. By adjusting the opening amount to a large state during foreign substance removal operation, the system increases oil discharge flow to push out deposited foreign substances while managing the impact on output pressure.
2Reliability
If the spool movement is inhibited by deposited foreign substances, then the oil pressure cannot be appropriately adjusted, but increasing spool movement to remove foreign substances causes large oil pressure reduction
Solution Approach 1:
The patent employs periodic action by controlling the coil current in a periodic manner during foreign substance removal operation. The current is applied intermittently to move the spool back and forth, creating periodic motion that generates sufficient force to push out deposited foreign substances while managing oil pressure fluctuations.
Solution Approach 2:
The patent replaces purely mechanical spool movement with electromechanical control using a coil. The coil current generates electromagnetic force to drive the spool, allowing for precise control of spool position and movement patterns to remove foreign substances while minimizing impact on oil pressure stability.
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 solution ensures that foreign substances can be reliably removed without significantly lowering the output pressure, maintaining the hydraulic circuit's oil pressure and preventing operational disruptions.
Implementation Method 1
a spool (11) that strokes to one side in an axis X direction by conduction of current to a coil (12)
Implementation Method 2
a spring (13) that urges the spool (11) to the other side in the direction of an axis X
Data Source
AI summary
A pressure control valve includes a spool that strokes to one side in the direction of an axis due to the conduction of current to a coil, a spring that urges the spool to the other side in the axis direction, a control device for controlling the conduction of the current to the coil, a determination unit for determining the start of a foreign substance removing operation by the spool, a command value setting unit for setting a command value for the current conducted to the coil, and a dither current setting unit for setting a dither current superimposed on the command value. When the determination unit determines the start of the foreign substance removing operation, the dither current setting unit changes an oscillation frequency of the dither current to an oscillation frequency lower than the frequency at the current point in time, and the command value setting unit periodically increases and reduces the command value on which the changed oscillation frequency is superimposed.