Connecting and unlocking mechanism driven by SMA wire

The invention relates to a connecting and unlocking mechanism driven by an SMA wire, which is provided with a split nut, a restraint device for the split nut and a driving device for the restraint device, wherein the split nut is used for connecting a bolt thread and is completely divided into a plurality of valves, and the outer side of the split nut is provided with a boss; the restraint devicefor the split nut is arranged outside the split nut, and the inner side of the restraint device is provided with a groove capable of being matched with the boss; in a connection state, the boss leansagainst the part of the restraint device outside the groove so as to maintain the radial constraint for the split nut; in an unlocking state, the boss enters the groove so as to loosen the radial constraint for the split nut; and the driving device for the restraint device comprises the SMA wire pulling the restraint device to move axially downward when being heated to shrink to enter the unlocking state, and a reset spring arranged below the restraint device. In an alternative scheme, when the SMA wire is not heated any more, the restraint device is pushed to reset axially upwards to enter the connection state again. The connecting and unlocking mechanism has completely unlocking, high success rate and high reliability.