Four-way valve and air conditioning system provided with same

A four-way valve comprising a valve body, a piston and two sealing members, the valve body having a valve cavity, the piston being movably disposed in the valve cavity, the two sealing members being disposed on the piston and at least a part of each of the two sealing members being capable of abutting against an inner wall of the valve cavity;

• wherein the valve cavity is separated into a high-pressure chamber and a low-pressure chamber by the piston, the high-pressure chamber and the low-pressure chamber are mutually independent;
• the piston is provided with only one first air passage, and the first air passage is in communication with the two sealing members and in communication with the high-pressure chamber, and a high-pressure medium in the high-pressure chamber is capable of pressing the two sealing members against the inner wall of the valve cavity through the first air passage;
• two gaps are formed between the piston and the two sealing members on both sides of the piston correspondingly, the gap extends in an axial direction of the valve body, and two ends of the first air passage are both directly in communication with the two gaps;
• and
• the first air passage extends from a sealing member on one side of the piston to the sealing member on the other side of the piston.