Jtekt Corporation

Tetsuya Kaneko

Toshihiro Asakura

Satoshi Fujita

Kazushi Numazaki

Akira Nakano

Masayoshi Asakura

Yuya Kihara

Kazuhiro Takabayashi

Kazuo Haneda

Takuya Nakayama

Masashi Yamaguchi

Takashi Hara

Ryuji Shibata

Yuichi Yamanaka

A pressure reduction valve includes a body including a gas passage, a valve seat provided in the gas passage, and a valve member provided on a downstream side of the valve seat in the gas passage. The gas passage includes a primary-side passage section located on an upstream side of the valve member, and a secondary-side passage section located on a downstream side of the valve member. The primary-side passage section includes a pressure chamber, which is a space formed between the valve member and the valve seat. The valve member includes a valve member passage that connects the pressure chamber to the secondary-side passage section, and an auxiliary passage configured to assist gas that flows into the pressure chamber through a clearance between the valve member and the valve seat to flow out to the secondary-side passage section.

Pressure reduction valve

A pressure reducing valve includes: a body, a valve seat, and a valve element opening and closing the valve seat according to a difference between a pressure on the inlet side and a pressure on the outlet side. A pressure chamber, which is a space part between the valve element and the valve seat, is provided on the inlet side of the valve element. The valve element includes a plurality of horizontal holes each opening to the pressure chamber, and a vertical hole bringing the horizontal holes and the outlet side of the valve element into communication with each other. The horizontal holes and the vertical hole are provided in such a manner that a value of a ratio of a flow channel area of the vertical hole to a total area that is a total of flow channel areas of the horizontal holes exceeds 1.16.

Pressure reducing valve

A ball screw device includes a screw shaft having a first screw groove formed on an outer circumference thereof, a ball screw nut having a second screw groove formed on an inner circumference thereof, and a plurality of balls disposed in a spiral ball raceway wherein the first screw groove and the second screw groove face each other. A circulation member is attached to an attachment hole radially penetrating the ball screw nut and a circulation path is formed, the circulation path allowing endless circulation of each of the balls rolling in the ball raceway by short-circuiting between two points of the ball raceway.

Ball screw device

A rack housing and a reduction drive housing accommodate a ball screw mechanism and a reduction drive. Within the rack housing and the reduction drive housing, a gap is provided between the left end of a nut and the rack housing, and a gap is provided between the right end of the nut and the rack housing. A groove serving as a communication path in communication with the gaps on both axial sides of the nut is provided in the outer circumferential surface of the nut. The groove is provided so as to avoid a recirculation path provided in the nut. The groove is provided axially and rectilinearly from the end of the nut that is located on the side opposite to a flange, to the flange and is provided along the flange.

Steering apparatus

A ball screw device is provided for which quality can be easily evaluated. The ball screw device includes a threaded shaft with a groove formed on an outer peripheral surface of the shaft, and a cylindrical nut whose screw-thread mates with the groove on the threaded shaft via a plurality of balls. The nut has a pair of mounting holes in each of which a deflector is installed and a communication groove that allows the mounting holes to communicate with each other and is open on the outer peripheral surface of the nut and through which the balls can roll. The width W of an opening of the communication groove is smaller than the diameter of the ball.

Ball screw device, power transfer mechanism, electric power steering apparatus, and method for manufacturing ball screw device

In an electric power steering system, there is provided a ball screw deflector configured to make it possible to easily measure the whole length of each of deflector pieces. A mating face of each of the deflector pieces and end faces of the deflector pieces are parallel to each other, and have an angle corresponding to a lead angle of a ball screw portion. Thus, it is possible to reduce the amount of material required to form each of the deflector piece pieces. In addition, it is possible to easily measure the overall length of each of the deflector pieces with the use of measuring equipment such as a vernier caliper.

Ball screw deflector

An electric power steering apparatus transmits rotational force of a motor to a rack shaft via a driver pulley, a belt, a driven pulley, and a ball nut. A ball bearing and the driven pulley are fitted to the outer circumferential surface of the ball nut. Also, the ball nut is rotationally supported to the inner circumferential surface of a housing via the ball bearing. A female thread portion is formed on the inner circumferential surface of the driven pulley. The ball nut has a male thread portion formed in a first end and a flange formed in a second end. By fastening the male thread portion and the female thread portion to each other, the ball bearing is clamped between the flange and the driven pulley, while the ball nut and the driven pulley are fastened to each other.

Electric power steering apparatus

Assist force that assists an operation of a steering system of a vehicle is applied to a rack shaft by transmitting driving force of a motor to the rack shaft via a motor shaft and a ball screw nut. A step is formed on the outer periphery of the ball screw nut. An end portion of a third housing is arranged to face a bearing such that the distance that the ball screw nut is able to move relative to the motor shaft in axial direction and the relative movable length is longer than a predetermined length.

Electric power steering system

The ball screw apparatus includes a returning way Lby mounting a circulating memberin mounted holesformed in the ball screw nut. The ball screw nutincludes a base portionand an expanding portion. In the base portiona distance from an axis center Oof the rack shaftto a bottom portionof the nut side screw grooveis constant, and in the expanding portionthe distance is larger than that of the base portion. The expanding portionincludes a connecting area

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Okazaki, Japan

Tetsuya Kaneko