| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric steering device preventing fluctuation of preload applied to a rotating shaft and an input shaft of a speed reduction mechanism even when temperature is changed and having an electric motor suppressing increase in a load current. SOLUTION: Even when the temperatures of the electric motor 6 and a housing 65 are changed, since materials of a motor case 61, the rotating shaft 64 and a worm gear 66 have approximately equal thermal expansion coefficients, the thermal deformation quantities of the motor case 61, the rotating shaft 64 and the worm gear 66 do not vary with each other and the preload applied to the worm gear 66 and the rotating shaft 64 by a deep groove type radial ball bearing 68 and a slide thrust bearing 673 is not increased/decreased. Therefore, even when the temperature is changed, since increase in load applied to the rotating shaft 64 during operation of the electric motor 6 can be suppressed, increase in the load current of the electric motor 6 can be suppressed. COPYRIGHT: (C)2008,JPO&INPIT |
