Solenoid Drawing
Three-Position Latching Solenoid
Data Sheet
Three-Position Latching Solenoid
Three-Position Latching Solenoid
A manufacturer of automobile door lock systems needed to add an emergency lock release feature to their passive entry door lock system. The emergency lock release would allow passengers to unlock the doors even when the key was turned on. This was an important function especially in the event of a car accident where the electrical system had been damaged and passengers needed to exit the vehicle.
It was determined that a three-position latching solenoid would provide the best solution for the application. The latching solenoid designed by TLX allowed the solenoid to perform three necessary functions in the door lock system. One position would lock the doors. Another position would handle the passive entry function and unlock the door. The third position would provide the emergency escape lock release needed in case of an accident when the key was still “on” but passengers needed to exit the vehicle. The new design provided by TLX for this custom three-position latching solenoid used only one spring which expanded against a hard stop to center the armature and compress when the armature moved in either direction. This gave a tighter tolerance on the solenoid’s center position and eliminated the need to set up and adjust two springs. The custom solenoid used a shunt ring to increase the pull-in force compared to traditional three-position latching solenoids. This allowed the solenoid to be smaller given the same voltage and current requirements. The new custom solenoid easily replaced the existing solenoid while adding the additional function required by the manufacturer.
For applications requiring high latching forces and compact design, this custom three-position latching solenoid provides an excellent energy efficient solution. Strokes and forces are flexible depending on solenoid size. This solenoid design can be made with either a permanent magnet or residual magnetism technology.
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