Electric linear actuator

An electric linear actuator comprising:

• an output shaft which is displaceable in an axial direction and non-rotatable about its axis and which has one end thereof coupled to a driven device;
• a cylindrical member arranged coaxially with said output shaft and rotatably about said output shaft, and driven in rotation by an electric motor;
• and
• a feed screw mechanism arranged between said output shaft and said cylindrical member for converting a rotating motion of said cylindrical member to a linear motion of said output shaft,
• said feed screw mechanism including:
• a male spiral groove formed in an outer peripheral surface of said output shaft;
• a nut cylinder secured on an inner peripheral surface side of said cylindrical member and having a female spiral groove formed in an inner peripheral surface thereof, and formed with a communicating path extending in a direction orthogonal to said female spiral groove and communicating between two adjacent portions of said female spiral groove spaced in the axial direction;
• a plurality of balls accommodated between both spiral grooves;
• and
• a pair of deflectors respectively secured toward opposite end portions of said female spiral groove for returning moving balls from each of said adjacent portions to the other through said communicating path.