An inshot pressure limiting mechanism, comprising: a valve body, an inshot valve, an inflation valve, and a pressure limiting member, wherein the valve body is provided with an air inlet, a first chamber, a second chamber, and an air outlet, and both the first chamber and the second chamber are in communication with the air inlet, and the first chamber is in communication with the second chamber; the inshot valve is provided in the first chamber; the inflation valve is provided in the second chamber; the pressure limiting member is provided in the valve body, and a pressure limiting chamber is formed between the pressure limiting member and the valve body, the pressure limiting chamber is in communication with the air outlet, and both the pressure limiting chamber and the air outlet are in communication with the second chamber; and the inshot valve and the inflation valve are both connected to the pressure limiting member, and the pressure limiting member is configured to drive the inshot valve and the inflation valve to move during pressure change in the pressure limiting chamber, so that the first chamber and the second chamber are simultaneously in an open state; or the first chamber is in a closed state, and the second chamber is in an open state; or the first chamber and the second chamber are simultaneously in a closed state; characterized in that: the inshot pressure limiting mechanism further comprises a contraction plug; and the valve body is further provided with a first passage and a second passage; the first passage makes the air inlet communicate with the first chamber, the second passage makes the air inlet communicate with the second chamber; and the contraction plug is provided in the second passage. a valve body, an inshot valve, an inflation valve, and a pressure limiting member, wherein the valve body is provided with an air inlet, a first chamber, a second chamber, and an air outlet, and both the first chamber and the second chamber are in communication with the air inlet, and the first chamber is in communication with the second chamber; the inshot valve is provided in the first chamber; the inflation valve is provided in the second chamber; the pressure limiting member is provided in the valve body, and a pressure limiting chamber is formed between the pressure limiting member and the valve body, the pressure limiting chamber is in communication with the air outlet, and both the pressure limiting chamber and the air outlet are in communication with the second chamber; and the inshot valve and the inflation valve are both connected to the pressure limiting member, and the pressure limiting member is configured to drive the inshot valve and the inflation valve to move during pressure change in the pressure limiting chamber, so that the first chamber and the second chamber are simultaneously in an open state; or the first chamber is in a closed state, and the second chamber is in an open state; or the first chamber and the second chamber are simultaneously in a closed state; characterized in that: the inshot pressure limiting mechanism further comprises a contraction plug; and the valve body is further provided with a first passage and a second passage; the first passage makes the air inlet communicate with the first chamber, the second passage makes the air inlet communicate with the second chamber; and the contraction plug is provided in the second passage. the inshot pressure limiting mechanism further comprises a contraction plug; and the valve body is further provided with a first passage and a second passage; the first passage makes the air inlet communicate with the first chamber, the second passage makes the air inlet communicate with the second chamber; and the contraction plug is provided in the second passage.