US Patent 7851952 Voice coil motor with guiding posts and stopping bars

An exemplary voice coil motor includes a hollow stationary magnetic field generator, a movable magnetic field generator, two elastic members, a hollow case and a base. The movable magnetic field generator is received in the stationary magnetic field generator. The two elastic members are adjacent to two ends of the stationary magnetic field generator. The case and the base serve as a package for all of the above elements. The case has a top sheet. The movable magnetic field generator has guiding posts slidably received in the top sheet, and stopping bars. The stopping bars of the movable magnetic field generator are capable of limiting the movement of the movable magnetic field generator toward the top sheet by abutting the top sheet.