| 摘要 |
An electric power steering system that is able to keep an optimal center distance between a worm gear and a wheel gear while suppressing generation of noise with a simple configuration is provided. The electric power steering system includes a shaft coupling (61) that drivably couples a worm gear (26) to an output shaft (48) such that the worm gear (26) is tiltable with respect to the output shaft (48). The shaft coupling (61) includes a fixing part (71) coupled to the output shaft (48) and a cylindrical part (72) having an inner periphery (75) in rectangular cross section and fixed to the fixing part (71). A coupling part (81) that is inserted in the cylindrical part (72) and that has an outer periphery (82) in non-circular cross section, engageable with the inner periphery (75), is formed at a proximal end part (62) of the worm gear (26), and the outer periphery (82) is ridged such that gaps (84) that allow the coupling part (81) to tilt are provided inside the cylindrical part (72). Then, the cylindrical part (72) presses an inner ring (51a) of the first rolling bearing (51) toward an axially distal end side of the worm gear (26). |
