公开(公告)号：EP1571356B1

公开(公告)日：2011-06-08

申请号：EP03777301.7

申请日：2003-12-05

申请人： JTEKT Corporation

发明人： YASUDA, Hirotaka c/o Koyo Seiko Co., Ltd. ,  KUSANO, Hirotsugu c/o Koyo Seiko Co., Ltd. ,  YAMADA, Wataru c/o Koyo Seiko Co., Ltd. ,  SAITO, Yoshiyuki c/o Koyo Seiko Co., Ltd. ,  HIRAKUSHI, Shuzo c/o Koyo Seiko Co., Ltd.

IPC分类号： B62D5/04 ,  F16H1/16 ,  F16C19/06 ,  F16C33/58 ,  F16C33/32 ,  F16C35/063

CPC分类号： B62D5/0409 ,  F16C19/06 ,  F16C19/54 ,  F16C33/585 ,  F16C2240/76 ,  F16C2326/24 ,  F16C2361/61 ,  F16C2380/27 ,  F16H1/16 ,  F16H55/24 ,  F16H57/021 ,  F16H2057/0213 ,  Y10T74/19828

摘要： Deep groove ball bearings are used as bearings (20, 30) supporting both side portions of a worm (14) that continues to a motor (10). In a first bearing (20) on the motor (10) side, curvature radii (R1, R2) of raceway grooves (21a, 22a) of an inner and an outer ring (21, 22), respectively, are set in a numerical range that satisfies at least either a first condition where the curvature radius (R1) is between 52.5% or more and 75% or less of a diameter (r) of a ball (23) or a second condition where the curvature radius (R2) is between 53.5% or more and 85% or less of the diameter (r) of a ball (23).