Abstract：Due to the launch vibration environment

the use of locking device is necessary for magnetic bearing wheels. We developed a electromagnetic locking device based on self-locking for our magnetic bearing reaction wheel

the mass of the locking device is 158 gram

and the dimension is 45mm×49mm×40mm. The link created by the locking device can be completely released by the compression spring. The mathematical models of lock and release are established. The curves of the locking force versus displacement and the releasing force versus displacement are given. The force of holding locking is 133.8 N

and the force of holding releasing is -9.4N. The ground environment and space environment are considered in this paper

the effect of gravitation is very small for the locking device. The locking device is tested by the vibration table.