| 摘要 |
An electrically driven linear actuator, which can suppress the generation of vibration or noise even if an alternating load or vibratory load is applied to the actuator, has an electric motor mounted on a housing. A screw shaft is coaxially connected to a motor shaft of the electric motor. The screw shaft is formed with a screw groove on its outer circumferential surface. A nut, threadably engaged with the screw shaft, has a pair of support shafts on its outer circumferential surface. The support shafts support one end of a link. The nut is formed with a screw groove on its inner circumferential surface. The nut screw groove corresponds to the screw groove of the screw shaft. A number of balls are contained between the screw grooves. Ball circulating members are coupled with the nut. Each ball circulating member is formed with an endless ball circulating passage between the screw grooves. The ball screw converts a rotary motion of the electric motor to an axial motion of the nut, in turn, causing a swing motion of the link, via the support shafts. A pair of support bearings rotatably supports the screw shaft in the housing. However, the screw shaft is axially immovably supported relative to the housing. One supporting bearing, arranged at the electric motor side, of each pair of the supporting bearing is an angular ball bearing. The other support bearing is a sliding bearing.
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