Ball screw device, power transfer mechanism, electric power steering apparatus, and method for manufacturing ball screw device

摘要

A ball screw device is provided for which quality can be easily evaluated. The ball screw device includes a threaded shaft with a groove formed on an outer peripheral surface of the shaft, and a cylindrical nut whose screw-thread mates with the groove on the threaded shaft via a plurality of balls. The nut has a pair of mounting holes in each of which a deflector is installed and a communication groove that allows the mounting holes to communicate with each other and is open on the outer peripheral surface of the nut and through which the balls can roll. The width W of an opening of the communication groove is smaller than the diameter of the ball.

主权项

1. A ball screw device comprising:
a threaded shaft with a groove formed on an outer peripheral surface of the shaft; and a cylindrical nut whose screw-thread mates with the groove on the threaded shaft via a plurality of balls, wherein the nut comprises a pair of mounting holes in each of which a deflector is installed, and a communication groove that allows the mounting holes to communicate with each other, an opening of the communication groove is formed on an outer peripheral surface of the nut, and the balls are able to roll through the communication groove, and a width of the opening of the communication groove is smaller than a diameter of the balls, the communication groove extends in a direction parallel to an axis of the nut and connects the mounting holes together.