Optimization and Validation of Pressure Switch Diaphragm for Lift Axle System

Lift axle system is widely used in trucks and trailer to enhance the load carrying capacity by lowering the axle. Nowadays, this raising or lowering the axle is automated using electronic pressure switch. The Electronic pressure switch is used to sense the pneumatic pressure from Load Detection valve in Lift Axle control system and activates the solenoid valve which aids in filling the air in the lift bellows. The configuration used in this switch is Single Pole Double Throw (SPDT) which has 3 terminals such as 1 common contact,1 Normally open (NO) & 1 Normally closed (NC). The contact of the switch changes its state at forward switching pressure and returns to its normal state at the reverse switching pressure. During lab validation process, pressure leakage and diaphragm puncture is observed. Rubber diaphragm is one of the critical elements in this pressure switch which is used to avoid any leakage during the pressure transfer from the load detection valve. This rubber diaphragm is placed between the outer body of the switch and sensor holder. This is held in position as metal body is crimped with the top plate. Since the diaphragm is made up of hyper-elastic material (Rubber) which is highly non-linear in nature. The sealing behavior of the diaphragm is dependent on various parameter such as geometry, hardness, chemical composition and squeezing level due to crimping process. In this paper, the sealing parameter of the diaphragm such as contact pressure, fluid opening pressure under various temperature condition is optimized by modifying the diaphragm and its mating components using Finite Element Analysis software such as Ansys, LS-Dyna and validation has been performed to correlate the simulation results.