Motor-driven power steering apparatus

A motor-driven power steering apparatus comprising:

• a drive gear driven by an electric motor, the drive gear being pivoted to a gear housing;
• a driven gear engaging with the drive gear, the driven gear being fixed to a steering shaft;
• and
• a preload means energizing a bearing of the drive gear in a predetermined preload direction in such a manner as to apply a preload to an engagement portion between the drive gear and the driven gear,
• wherein the preload means comprises:
• a bearing case which is provided with a bearing accommodating hole accommodating the bearing of the drive gear, is provided with a spring accommodating hole accommodating a spring for energizing the bearing so as to cross the bearing accommodating hole, and is provided in an outer periphery with a guided portion;
• and
• a guide case which is provided with a guide hole accommodating the bearing case, and is provided in an inner periphery of the guide hole with a guide surface coming into contact with the guided portion of the bearing case and guiding in such a manner that the bearing case moves in a predetermined preload direction of the bearing, and
• wherein the guide case accommodating the bearing case in which the bearing and the spring are accommodated is attached to an attaching portion which is provided in the gear housing.