Jtekt Corporation

Koyo Seiko Company, Ltd.

Kosuke Yamanaka

Daisuke Maeda

Atsushi Ishihara

Shiro Nakano

Shingo Maeda

Masanori Arima

Naoki Maeda

Tatsuma Kouchi

Kenji Higashi

Tomoyasu Kada

Masami Naka

Takeshi Ueda

Akihiko Shiina

Toshiaki Oya

Kazuya Yoshioka

Sadahiro Kawahara

Hiroaki Sougumo

Masakazu Furuyoshi

Provided is a vehicle steering system that is able to restrict a travel amount of a steered shaft in a housing, that is small and that has an excellent strength. The vehicle steering system is a steer-by-wire vehicle steering system that converts rotative power of electric motors into a movement of a steered shaft in an axial direction via a ball screw mechanism. One of contact portions at respective ends of a screw shaft at an intermediate part of the steered shaft passes through a rotor based on a moving direction of the steered shaft so as to contact a corresponding one of the corresponding stoppers thereby restricting a travel amount of the steered shaft. The stoppers are made of a material different from that of the housing and having a high strength.

Vehicle steering system and manufacturing method for vehicle steering system

A ball screw device has a plurality of spiral raceways. One end and the other end of each raceway is connected via a bridge. An annular flange of a ball nut has a plurality of mounting portions at equal intervals in a circumferential direction. A fixing screw is fitted to each mounting portion. The bridges arranged so as to overlap with the annular flange in position in an axial direction are arranged at positions different in the circumferential direction from positions at which the mounting portions are arranged, and are arranged at unequal intervals in the circumferential direction.

Ball screw device, linear actuator and vehicle steering system

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 vehicle steering system includes a steered shaft, and stoppers which restrict an amount of movement of the steered shaft in an axial direction. The steered shaft has first outer peripheral faces, second outer peripheral faces, and annular stepped portions. Each stepped portion includes a contact portion that faces a corresponding one of the stoppers in the axial direction, a first corner portion that has a concave curved sectional shape and connects the first outer peripheral face to an inner end of the contact portion, and a second corner portion that has a concave curved sectional shape with a larger curvature radius than that of the first corner portion, and connects the first outer peripheral face to the second outer peripheral face, at a position in front of or behind a central axis of the steered shaft.

Vehicle steering system

A configuration is provided which includes a differential gear-type transfer ratio varying mechanism interposed between an input shaft which rotates as a steering wheel is operated and an output shaft which rotates in conjunction with operation of a steering mechanism for permitting a differential operation between both the shafts, the configuration including a transfer ratio control motor for applying a rotational force to the output shaft, a reaction force control motor for applying a rotational force to the input shaft, and a steering control unit for controlling and driving the transfer ratio control motor to obtain a rotation transfer ratio that is predetermined according to operation of the steering wheel and controlling and driving the reaction force control motor to apply a predetermined reaction force to the steering wheel.

A variable stiffness stabilizer device () has a stabilizer bar () and actuators (). The stabilizer bar () has a torsion bar () extending in the lateral direction (X) of a vehicle and arms () connected through bend portions () to the ends () of the torsion bar () and bendingly deformed according to the strokes of wheel supporting members (). Variable bending stiffness parts () of the arms () are rotatable about the axes (C) of the arms (), so that the bending stiffness of the arms () can be changed according to their rotational positions. The actuators () rotationally drive the variable bending stiffness parts () about the axes (C) to adjust the rotational positions of the variable bending stiffness parts ().

Variable stiffness stabilizer device

A planet gear mechanisminterposed between a steeringand steerable wheelsL andR is interposed. A torque controlling motorfor controlling a torque acting on the steeringand a transmission-rate varying motorfor driving the planet gear mechanismare arranged coaxially (on an axial A) with the planet gear mechanism. This eliminates the need for arranging each motorandon the both ends of the axis A to face each other, and also reduces a space occupied by the motorsandwith respect to a radial direction of the axis A. As a result, reduction in the size of an apparatus can be achieved.

Steering apparatus for motor vehicle

There is provided a vehicle steering system which includes an electric motor for imparting a steering force to a steering mechanism of a vehicle and an automatic parking controller for executing an automatic parking control by controlling the electric motor, wherein the automatic parking controller controls an energizing voltage of the electric motor by imparting a square wave to the electric motor and increasing/decreasing a neutral point voltage of a winding of the electric motor.

A steering apparatus for vehicle comprises a steering shaft including a first portion connected to a steering member and a second portion connected to steerable wheels; a transmission ratio variable mechanism capable of varying a transmission ratio as a ratio of a steered angle of the steerable wheels to a steering angle of the steering member; and a reaction-force compensation motor for compensating a steering reaction force of the steering member caused by the operation of the transmission ratio variable mechanism. The transmission ratio variable mechanism includes a differential mechanism for differentially rotatably interconnecting the first and second portions; and a differential-mechanism motor for driving the differential mechanism. Both an axis of a rotary shaft of the differential-mechanism motor and an axis of a rotary shaft of the reaction-force compensation motor are aligned with an axis of the steering shaft.

Steering apparatus for vehicle

A steering device for a vehicle includes a first sun gear connected to a steering member, a second sun gear which is operated according to operation of the steering member and connected to a steering mechanism for turning vehicle wheels, a first planet gear which is meshed with the first sun gear, and a second planet gear which is rotated integrally with the first planet gear and meshed with the second sun gear. The steering device is constructed in such a manner that at least one of the first and second sun gears is a profile shifted gear, and the first and second planet gears are formed as a cylindrical body which has internal teeth of the same number at both end parts thereof.

Steering device for vehicle

A rotation transmitting apparatus comprises a first sun gear joined to a first shaft so as to rotate interlockingly, a second shaft arranged to the first shaft coaxially, a second sun gear joined to the second shaft so as to rotate interlockingly, a first planetary gear meshed with the first sun gear, a second planetary gear rotating with the first planetary gear and meshed with the second sun gear, and a carrier supporting the first and second planetary gears and arranged to be driven by a differential electric motor. In particular, the number of teeth of each of the first and second sun gears and the first and second planetary gears is determined so that the ratio of a torque applied to the second shaft to a torque applied to the first shaft ranges from 1:0.7 to 1:0.9.

Steering apparatus

A steering device for a vehicle includes a planet gear mechanism which can vary transmission ratio, and a lock mechanism for fixing the transmission ratio. The planet gear mechanism includes a first sun gear connected to a steering member, a second sun gear connected to turning wheels, a planet gear which is meshed with both the first and second sun gears and a carrier in an annular shape which supports the planet gear. The lock mechanism includes a restraining member which is engageable with the carrier thereby to restrain rotation of the carrier.

A vehicle steering system is provided which includes a variable angle ratio mechanism for changing an angle ratio of a steering angle of a steering member to a turning angle of a steering mechanism, the variable angle ratio mechanism including a first sun gear connected to a steering column, a second sun gear connected to the steering mechanism, and planetary gears each having a first toothed portion and a second toothed portion which are adapted to mesh with the first and second sun gears respectively, and are arranged to be spaced apart from each other in a tooth face width direction, the first toothed portion and the second toothed portion being formed integrally through forging.

In a steering-without-driving state, a larger current limit value, drive limit time and steering angle deviation threshold value are set than when a low-speed driving state occurs. An automatic parking mode is held until a time period over which a state where a motor current value of an electric motor which drives a steering mechanism is equal to the current limit value reaches the drive limit time. Even though the state where the motor current value is equal to the current limit value has continued over the drive limit time, the automatic parking mode is held during the steering angle deviation not exceeding the steering angle deviation threshold value. When the state where the motor current value is equal to the current limit value has continued over the drive limit time Ta and that the steering angle deviation exceeds the threshold value, the automatic parking control is cancelled.

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Kashihara, Japan

Kosuke Yamanaka