The present invention provides a durable main air valve for heavy
truck gear-box, relating to a shift main air valve of heavy
truck gear-box. The aim of the invention is to resolve the problem of easy damage of the shift main air valve of the present heavy
truck gear-box, not used for long period and difficult finish
machining of the valve base sealing face, the main air valve cling to inner wall is fixedly assembled with a sliding bush, a
rubber ring valve base component from left to right in orders, holes between the sliding bush and the
rubber ring valve base from left to right are slidely assembled with a
piston, a steel limit ring valve core, an aluminum
reversing valve core and a spring in orders, wherein, the right of the
piston and the left of the steel limit ring valve core are connected, the shaft drum external surface of the aluminum
reversing valve core and the seal ring of the
rubber ring valve base component form kinematical seal; the upper of the neutral gear bumper pin is inserted between the left baffle ring and the right baffle of the steel limit ring valve core, the right baffle ring sets multiple axial pylomes. The main air valve has a long using life, easy to process.