THERMAL EXPANSION VALVE

A thermal expansion valve, comprising a gas cavity head (40) and a valve body (10). The gas cavity head (40) and the valve body (10) are fixedly arranged. The gas cavity head (40) comprises a gas cavity base (42), a gas cavity base (41), and a membrane (43). The membrane (43) comprises a membrane concave part (431) and a wavy part (433). The membrane concave part (431) is located at the center position of the membrane (43). The wavy part (433) is located at the peripheral position of the membrane concave part (431). The concaving direction of the membrane concave part (431) is away from the gas cavity base (41). The valve body (10) comprises a top part (105). The top part (105) is provided with an opening (109). At least a part of the gas cavity head (40) is extended into the opening (109). With the axial direction of the valve body (10) being the direction of projection, the projection of the gas cavity head (40) towards the top part (105) falls on the top part (105). The size of the gas cavity head (40) is relatively smaller than that of the valve body (10) and favors a reduced weight.