This study is investigated by the analyses of modal and harmonic response on BH motor, VI motor and DH motor. The natural frequency of DH motor becomes lower than that of VI motor. As the maximum amplitude of displacement is shown to be 2.06×10-2mm at 1300 Hz in case of BH motor, BH motor can be thought to be the best structure in comparison with VI motor and DH motor. The deformation of 0.34806 mm happens at the critical frequency in case of BH motor. And the maximum deformation happens at the joint connected between screw axis and seat in cases of three kinds of motors. By applying the result of this study to the designs of these kinds of motors, it is thought that the damage of linked parts is prevented. As the durability can be examined and anticipated, this result can be utilized really

Various motors have been used in many cars to control the height of automotive seats. As the motor is connected with seat, it can be moved as the convenience of passenger and vibration affects passenger when motor is being driven. In this study, three models are designed. The lengths of link parts and screw axes are increased or decreased respectively in the order of models 1, 2 and 3. The case of motor is made of aluminum alloy and the rest is made of structural steel. As model 1 has the maximum amplitude displacement at 1360Hz by the basis of vibration analysis, model 1 has the most durability among three models. This study result can be effectively utilized with the design on height motor by investigating prevention and durability against its damage.