Actuator assembly having optimized 4-bar linkage type actuator arm, hard disk drive employing the same, and method for optimizing shape of opening formed in actuator arm

摘要

An actuator arm of an actuator assembly includes a 4-bar linkage structure defined by a trapezoidal shaped opening formed between a front end of the actuator arm and a pivot shaft. A first rounded extension portion and a second rounded extension portion are formed at two corners adjacent to the pivot shaft of the opening, respectively, and a third rounded extension portion is formed at two corners adjacent to a front end of the opening, and hinges H₁, H₂, H₃ and H₄ are formed at the actuator arm by the first, second and third extension portions. Design factors determining a shape of the opening are optimized to meet the following relations for the structure of the 4-bar linkage: W(cos β−1)+Z(cos α−1)=δ_x=0, W sin β+Z sin α=δ_y=0.