US Patent 7753337 Fluid injection valve

In a fluid injection valve, a valve needle and a moving core are installed in the valve housing to be slidable in an axial direction. The moving core has a through hole in which the valve needle is slidably inserted. A stopper provided on the valve needle moves the valve needle integrally with the moving core when the moving core travels toward the fixed core with respect to the needle valve. An elastic member biases the valve needle away from the fixed core, and a helical spring biases the moving core toward the fixed core. A spring seat supports one axial end of the helical spring in both of the axial direction and a radial direction of the helical spring.