PROBLEM TO BE SOLVED: To provide a ball screw device which defines a shape of a ceiling surface of each deflector and unfailingly has an overlap allowance between rolling balls and a retainer when the rolling balls move in a connection passage, and to provide a steering device including the ball screw device.SOLUTION: A ball screw device 40 includes: a ball screw shaft 20; a ball nut 21; deflectors 43 each forming a connection passage 43b; rolling balls 44; and a retainer 45. The connection passage 43b is formed between an outer periphery rolling groove 23a1/a thread 52 and a ceiling surface 43c. When viewed in an axial direction, a projection shape of the ceiling surface 43c includes at least a first round part 56 which is formed having a first curvature radius R1 so that a first constant gap α1 is provided between the rolling balls 44 and the ceiling surface 43c, and a second round part which is formed having a second curvature radius R2 smaller than the first curvature radius R1 at the groove bottom side of the outer periphery ball rolling groove 23a1.SELECTED DRAWING: Figure 10
【課題】デフレクタの天井面の形状を規定し、転動ボールが連結通路内を移動する際、転動ボールとリテーナとの間には確実に係り代を有するボールねじ装置、及びボールねじ装置を備えるステアリング装置を提供する。【解決手段】ボールねじ装置40は、ボールねじ軸20と、ボールナット21と、連結通路43bを形成するデフレクタ43と、転動ボール44と、リテーナ45と、を備える。連結通路43bは、外周ボール転動溝23a1及びねじ山52と天井面43cとの間に形成され、天井面43cは、軸線方向から見たときの投影形状が、少なくとも、転動ボール44と天井面43cとの間に一定の第一隙間α1が設けられるように、第一曲率半径R1で形成される第一R部56と、外周ボール転動溝23a1の溝底側において、第一曲率半径R1より小さな第二曲率半径R2で形成される第二R部と、を備える。【選択図】図10
BALL SCREW DEVICE AND STEERING DEVICE INCLUDING BALL SCREW DEVICE
ボールねじ装置、及びボールねじ装置を備えるステアリング装置
2018-07-19
Patent
Electronic Resource
Japanese
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