The utility model relates to an automatic door opening and closing mechanism and door box equipment. The automatic door opening and closing mechanism comprises a hinge
spring system which comprises a hinge
assembly, a linkage piece connected with the hinge
assembly and a spring connected to the linkage piece; the tensioning driving
system comprises a driving mechanism, a transmission arm and a tensioning wheel, the transmission arm is in driving connection with the driving mechanism, the tensioning wheel is arranged on the transmission arm and used for tensioning the linkage piece, and the transmission arm is driven by the driving mechanism to drive the tensioning wheel to move among a first position, a second position and a third position; when the tensioning wheel is located at the second position, the linkage piece applies a tension moment balanced with the gravity moment to the door body
assembly under the action of the spring; when the tensioning wheel is located at the first position, the linkage piece applies tension moment smaller than gravity moment to the door body assembly so as to break moment balance. When the tensioning wheel is located at the third position, the linkage piece applies the tension moment larger than the gravity moment to the door body assembly so as to break moment balance.