To provide a high-accuracy and high-strength hollow threaded shaft with a low wall thickness, a method for manufacturing the same, and a small and light-weight ball screw unit.
The method for manufacturing the threaded shaft includes steps of rolling the outer periphery of a rod-shaped steel material 20 to form helical thread grooves 3a, applying heat treatment to the outer periphery, boring the heat-treated rod-shaped material 20 to form into a tubular shape, thus manufacturing the hollow threaded shaft 3. The hardness of a thread groove surface of the threaded shaft 3 is higher than Hv600, the hardness of the inner periphery is higher than Hv180 and lower than Hv400, and the wall thickness is 0.65 mm or larger and 50% or smaller in an inner radius. A ball screw 1 provided with the threaded shaft 3 is combined with rolling bearings 30, a fixing shaft 32, and contents of a motor 38 to form the ball screw unit. The contents are included in a hollow part of the threaded shaft 3.
SAITO SHINGO
HASHIMOTO KOJI
Megumi Konishi
Hide Tanaka Tetsu
Ichi Hirose
Toru Miyasaka
Next Patent: PRODUCT MEASUREMENT POSITION CORRECTION METHOD AND CROP PART SHEARING METHOD FOR ROLLED STEEL PLATE