US 11,807,312 B2
Power steering device
Keisuke Kitamura, Atsugi (JP); Kohtaro Shiino, Isehara (JP); Osamu Yoshida, Yokohama (JP); Tatsuyoshi Maruyama, Atsugi (JP); and Norihiro Kimura, Atsugi (JP)
Assigned to HITACHI ASTEMO, LTD., Hitachinaka (JP)
Appl. No. 16/960,345
Filed by HITACHI AUTOMOTIVE SYSTEMS, LTD., Hitachinaka (JP)
PCT Filed Dec. 11, 2018, PCT No. PCT/JP2018/045393
§ 371(c)(1), (2) Date Jul. 7, 2020,
PCT Pub. No. WO2019/138757, PCT Pub. Date Jul. 18, 2019.
Claims priority of application No. 2018-002274 (JP), filed on Jan. 11, 2018.
Prior Publication US 2020/0369314 A1, Nov. 26, 2020
Int. Cl. B62D 5/04 (2006.01); F16H 25/22 (2006.01)
CPC B62D 5/0448 (2013.01) [F16H 25/2214 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A power steering device comprising:
a steered shaft having a spiral steered shaft-side ball screw groove;
a nut having a main body, a nut-side ball screw groove, a first communication passage and a second communication passage, wherein
the main body has a cylindrical shape, and the steered shaft is inserted into the main body,
the nut-side ball screw groove is a spiral groove formed at an inner peripheral side of the main body,
the first communication passage communicates with the inner peripheral side and an outer peripheral side of the main body, and
the second communication passage communicates with the inner peripheral side and the outer peripheral side of the main body;
a plurality of balls provided movable between the steered shaft-side ball screw groove and the nut-side ball screw groove and supporting the nut such that the nut can rotate relative to the steered shaft;
a tubular-shaped first circulation member having a first inserting part, a first bending section, a first connecting section and a first connecting end, wherein
the first inserting part is inserted into the first communication passage,
the first connecting section is located at an outer peripheral side of the nut, and
the first bending section is provided between the first inserting part and the first connecting section;
a tubular-shaped second circulation member having a second inserting part, a second bending section, a second connecting section and a second connecting end, wherein
the second inserting part is inserted into the second communication passage,
the second connecting section is located at the outer peripheral side of the nut,
the second bending section is provided between the second inserting part and the second connecting section, and
the second connecting end is provided at the second connecting section on an opposite side to the second bending section such that the second connecting end faces the first connecting end of the first connecting section and the plurality of balls are movable between the first circulation member and the second circulation member;
a fixing member having a first inserting part forcing portion, a second inserting part forcing portion and a connecting end position stopper, wherein
the first inserting part forcing portion forces the first inserting part in a direction in which the first inserting part is inserted into the first communication passage,
the second inserting part forcing portion forces the second inserting part in a direction in which the second inserting part is inserted into the second communication passage, and
the connecting end position stopper has a shape that stops a relative position shift between the first connecting end and the second connecting end; and
an electric motor driving and rotating the nut and moving the steered shaft in an axial direction of the steered shaft by rotation of the nut.