an expansion valve relating to the field of air conditioning technology . the present expansion valve comprises a housing , a cylindrical valve body with an inner cavity fixed inside the housing . in the inner cavity , there is a matched set of the first valve core and the second valve core sliding along it . a retaining ring is fixed in the inner cavity between the two valve cores . at both ends of the inner cavity there are spring assemblies driving the valve cores towards the retaining ring . a damping structure is also installed between the first valve core and the second valve core . in this manner , a cushioning effect is provided when the first valve core approaches the second valve core , which lightens the impacts to valve cores and thereby extend the service life of the expansion valve .