Jtekt Corporation

Kazuya Yoshioka

Kenji Higashi

Yasuyuki Yoshii

Shimon Jimbo

Shiro Nakano

Kosuke Yamanaka

Masami Naka

Shinsuke Terada

There are provided a ball screw that makes it possible to prevent a situation where a large load is applied to a part of a plurality of balls, and an electric power steering system including the ball screw. The ball nut is a component that surrounds a part of the male thread groove, and has a nut inner surface and a female thread groove. The female thread groove is formed in the nut inner surface, and forms a part of the rolling path. A female thread diameter varies according to a position in an axial direction of the ball nut. The female thread diameter is larger at each axial end of the ball nut than at an axially intermediate portion of the ball nut, and the female thread diameter is larger at one axial end than at the other axial end.

Ball screw and electric power steering system including ball screw

A steering shaft is composed of an upper shaft, a lower shaft, an input shaft, and an output shaft. The upper shaft, the lower shaft, and the input shaft can rotate together, and the input shaft and the output shaft are relatively rotatably coupled to each other via a torsion bar. The rotational position of a rotor coupled to the output shaft is calculated based on the detected rotational position of the lower shaft and a steering torque detected based on the amount of relative rotational displacement of the input shaft and the output shaft. Thus, it is not necessary to include a rotor rotational position detecting unit for detecting the rotational position of the rotor within the electric motor, which reduces the size of the electric motor.

Electric power steering device

In an energy absorbing steering system including a steering shaft to which a steering member is coupled, and a steering column that rotatably supports the steering shaft, at least one of the steering shaft and the steering column includes an impact absorbing portion that contracts when a load equal to or higher than a predetermined value is applied, and the impact absorbing portion includes a first impact absorbing portion having a first impact absorption load, and a second impact absorbing portion having a second impact absorption load different from the first impact absorption load.

Energy absorbing steering system

A vehicle steering apparatus includes a steering member; a steering shaft connected to the steering member; a torque sensor for detecting a steering torque inputted into the steering member; and an electric motor for generating power that is transmitted to the steering shaft based on the steering torque detected by the torque sensor. The electric motor includes an annular rotor and an annular stator. The annular rotor includes an annular rotor core which coaxially surrounds the steering shaft and is rotatable together with a part of the steering shaft. An annular accommodation space is formed between an outer circumference of the steering shaft and an inner circumference of the annular rotor core, and at least a part of the torque sensor is disposed within the annular accommodation space.

Vehicle steering apparatus

A vehicle steering apparatus includes a jacket for rotatably supporting a steering shaft, and an electric motor. The electric motor includes an annular rotor arranged coaxially with the steering shaft and rotating together with the steering shaft. The jacket includes a tubular upper jacket and a tubular lower jacket that are fitted into each other and are moved axially relative to each other in the collision of a vehicle. An annular space surrounding the steering shaft is provided radially inside the rotor. A part of the upper jacket enters the annular space in the collision of the vehicle.

An electric power steering apparatus includes a steering assisting electric motor having a motor housing for accommodating an annular rotor and an annular stator. The rotor and the stator are disposed coaxially with a steering shaft. The motor housing is supported by a support member mounted to a vehicle body member. A shock applied to a steering member when the motor vehicle crashes is absorbed by the relative movement between the motor housing and the support member.

Growing community of inventors

Kashiwara, Japan

Kazuya Yoshioka