Thermal expansion valve easy to introduce membrane balance medium

The utility model relates to a thermal expansion valve which is easy to introduce diaphragm balance media. A fast channel of a cavity and a leading cavity, which is formed by the communication of a diaphragm and an air box seat is arranged on the transmission sheet. Under the condition that the good guide of the transmission sheet is ensured, the design that the transmission sheet is matched with a guide part is achieved; although the balance media enter the lower cavity of an air box head through a combining part of the guide part and the transmission sheet to generate irregular pressure force because of the definite eccentricity of the cooperation of the transmission sheet and the guide part, the unevenness can be reduced; besides, the fast channel can improve the speed of the balance media of entering the lower cavity from the leading cavity and improve the reaction speed when the diaphragm affects the external factors to change. In addition, owing to the arrangement of the fast channel, the quality of the transmission sheet can be reduced.