One known type of application and release magnet valve employed a pair of electromagnetic solenoids which controlled the condition of valving members to supply, hold, or release air pressure in a pneumatic brake system. In this previous solenoid valve, the armature gap had to be gauged and adjusted during the assembly of the valve. This adjustment was necessary in order to obtain the correct magnetic force required to open the valve members against the force of the biasing spring. Further, the dynamic O-ring seals used to prevent the flow of air around the stem of the valve member also included increased frictional resistance which could cause the valve to malfunction. This problem was exaggerated, especially when the silicon grease lubricant on the O-rings and O-ring grooves or shoulders is dispersed after the valve is in operation for a long period of time. In addition, as the O-rings wear, the area of the contact surfaces increases so that the dynamic frictional resistance is amplified and results in an increased amount of malfunctions. Further, the metallic dust escalates the chafing and wearing of the O-ring seals so that leakage becomes a problem.
USPTO Backgrounds
USPTO Backgrounds