Gear inerter negative stiffness friction damping device

The invention relates to the technical field of structural vibration control, in particular to a gear inerter negative stiffness friction damping device. Comprising a shell, a gear inerter system, a drum brake friction system and a straight rack for jointly driving the gear inerter system and the drum brake friction system, and further comprises a linear bearing and a rack limiter for limiting working planes of the gear inerter system and the drum brake friction system; the gear inerter system comprises a first-stage gear set and a second-stage gear set which are meshed with each other, any gear set comprises two straight gears which are oppositely arranged in a spaced mode and are different in size, the central axes of the two straight gears in each gear set are jointly provided with a transmission shaft, and the transmission shaft is connected through a flat key. Two ends of the transmission shaft are provided with rotating bearings connected with the shell; the drum brake friction system comprises a drivin