Back lash buffer

The invention relates to a back lash buffer which comprises a motor, a speed reducer, a control box and a drive shaft, wherein the motor is fixedly connected with the speed reducer, the speed reducer is fixedly connected with the control box, the motor is in drive connection with the speed reducer, the speed reducer is in drive connection with the drive shaft, the drive shaft penetrates through the control box, the control box comprises a box body, a first eccentric wheel, a second eccentric wheel, an elasticity adjusting device and an elasticity conducting device are arranged in the box body, the elasticity adjusting device and the elasticity conducting device are fixedly connected with the box body respectively, the first eccentric wheel and the second eccentric wheel are propped against the elasticity conducting device respectively, the elasticity conducting device is propped against the elasticity adjusting device, and the drive shaft penetrates through the first eccentric wheel and the second eccentric wheel respectively. An imported RV speed reducer and a high-resolution closed loop controller are not required to be used in the back lash buffer, and the back lash buffer is simple in structure, long in service life and low in production cost, can eliminate back lash produced by forward and reverse drive of gears and relieve blockage of great inertia on movement during manipulator movement, and improves the movement accuracy of a manipulator.