1. Field of the Invention
The present invention is directed to a step motor.
2. Description of the Related Art
An ODD (Optical Disk Driver) includes a step motor. The step motor is installed inside the optical disk driver to drive an optical pick-up. The optical pick-up travels along in a radial direction of an optical disk by means of a step motor whilst reading a data recorded in a disk or recording data into a disk.
In general, a step motor encompasses a bracket and a housing. The bracket and housing rotatably supports one end and the other end of a lead screw. One pair of bobbins may be installed at the inner part of a housing. A coil winds on the outer surface of a bobbin, and a tooth yoke is coupled at the inner surface of a bobbin. Around an outer surface of a lead screw positioned inside the housing is fixed a rotor.
In a case the housing is welded to a bracket, a coupling intensity between the housing and the bracket turns lowered. Thus, by an external force from outside, a warping of the bracket and/or housing may be easily observed.
When the housing and/or the bracket may be bent by the external force, a gap formed between the rotor formed on the lead screw and the stator is changed so that noise during the rotation of the lead screw may be generated or a torque of a step motor may be decreased.