Thermal expansion valve

The invention discloses a thermal expansion valve, belongs to the technical field of vapor compression-type refrigerating, and is suitable for an automobile air conditioner system. The thermal expansion valve mainly comprises a thermal head 1, a valve body 2, a valve rod 3, a steel ball base assembly 4, an adjustment spring 5 and the like. The thermal expansion valve is characterized in that the steel ball base assembly 4 comprises a steel ball 41, a steel ball base 42 and a damping spring 43. When a driver suddenly starts the automobile air conditioning system, the steel ball 41, the steel ball base 42 and the damping spring 43 constituting the steel ball base assembly 4 have constitute a whole though the valve rod 3 and the steel ball base assembly 4 may disengage, and the damping spring 43 is in interference fit with a valve hole 21. By means of the inhibition function of the damping spring 43, the situation that the steel ball base assembly 4 and the adjustment spring 5 vibrate due to external excitation