Jtekt Corporation

Jtekt Coporation

Takuya Nakayama

Toshihiro Asakura

Keisuke Ogawa

Minoru Sato

Hideya Kato

Tetsuya Kaneko

Tetsuro Furuhata

Eiji Yamazaki

Seiichi Ohno

A gear machining apparatus includes a rough working tool having a plurality of replaceable tool blades attached to a tool main body, such that the tool blades are arranged in a circumferential direction of the tool main body and blade tips of the tool blades are oriented outward in a radial direction of the tool main body, a finish working tool having a plurality of tool blades provided to a tool main body in a similar manner to the rough working tool, and machining controllers control to perform rough and finish machinings on the workpiece, such that the working tools are rotated on center lines in axial directions of the working tools, the workpiece is rotated on a center line in axial direction of the workpiece, and the working tools are relatively moved to the workpiece along the center line in the axial direction of the workpiece.

Gear machining apparatus and gear machining method

A ball screw nut has a pair of through holes and a first passage that allows the through holes to communicate with each other and that opens radially outward. In each of the through holes, a ball screw mechanism has a circulation member having a second passage in which a ball can move between a ball raceway and the first passage. The ball screw mechanism has a circulation path for communicating the two connection points set on the ball raceway by the first passage and each of the second passages. A driven pulley has a thin portion that defines a radial clearance between an inner periphery of the driven pulley and an outer periphery of the ball screw nut. The ball screw mechanism has a pressing lid that presses down each of the circulation members from the outer periphery of the ball screw nut and that covers the first passage.

Turning unit

A machine tool that generates internal teeth or external teeth on a cylindrical workpiece includes a workpiece holder, a column which is relatively movable to the workpiece holder, a rotary main spindle which is rotatable with respect to the column, a working tool which is held by the rotary main spindle, and a phase detecting unit which detects a phase of the working tool with respect to the rotary main spindle. The working tool includes a cutter portion which has cutters, a holder portion, and a detected portion which is formed on the holder portion. The phase detecting unit includes a detecting section which detects the detected portion, and a calculating section which calculates a phase angle of the detected portion with respect to a reference position of the rotary main spindle, based on a result detected by the detecting section.

Machine tool

To provide a ball screw device and a steering device capable of securing smooth circulation of balls while suppressing occurrence of clogging of the balls caused by displacement in a radial direction between a deflector and a nut main body. A ball screw device includes a ball screw nut and a circulation path. The ball screw nut includes a nut main body and a deflector. The deflector includes an inclined portion provided at a peripheral part of a connection portion between a passage and the circulation path of the nut main body for securing passing of the balls at the connection portion when an insertion position of the deflector with respect to the deflector mounting hole is displaced from a desired position within a range of a given distance.

Ball screw device and steering device

There provides a ceiling surface of a deflector which secures an allowance for engagement between a rolling ball and a retainer. A ball screw device includes a ball screw shaft, a ball nut, a deflector forming a coupling passage, a rolling ball, and a retainer. The coupling passage is defined by an outer circumferential ball rolling groove, a ridge, and a ceiling surface. The ceiling surface has a first rounded portion at which a projected shape of the ceiling surface seen in an axial direction has a first radius of curvature at least such that a constant first clearance is provided between the rolling ball and the ceiling surface, and a second rounded portion at which the projected shape has a second radius of curvature smaller than the first radius of curvature and which is located on a groove bottom side of the outer circumferential ball rolling groove.

Ball screw device and steering system including ball screw device

A steering system with a reduced number of parts is provided. A driven pulley has a radially outer portion, a radially inner portion, and a connection portion that connects the radially outer portion and the radially inner portion to each other. The radially inner portion is provided with a plurality of slits at equal intervals in the circumferential direction. A plurality of retention portions are provided at portions of the radially inner portion between the slits. Lug portions are provided on the inner surface of the distal ends of the retention portions. A groove is provided in the outer peripheral surface of a ball screw nut. The lug portions of the retention portions are fitted with the groove of the ball screw nut.

Steering system

A production method of a ball screw device is provided. The ball screw device includes a ball screw portion, a ball nut, rolling balls, and a retainer. The production method of the ball screw device includes: a first preparation step of preparing a nut subassembly as a standard product; a second preparation step of preparing the ball screw portion in plurality by types as ranked products; a measuring step of measuring a relative displacement in a thrust direction between the standard product and each ranked product; a determination step of determining whether the displacement meets a displacement specification; a replacing step of, if the displacement does not meet the specification, replacing the ranked product with another ranked product; and an assembling step of, if the displacement meets the specification, assembling the standard product and the ranked product into the ball screw device.

Production method of ball screw device and production method of steering system using ball screw device

A cylindrical retainer configured to retain balls in a rollable manner is provided inside a ball screw nut. The retainer has retainer grooves each having a shape of an elongated hole that extends in an axial direction of a ball screw shaft so as to be inclined at a predetermined angle. A first end of the ball screw nut and a first end of the retainer, which is one of two ends of the retainer that is closer to the first end of the ball screw nut, are spaced away from each other by a distance. The terminal end of the retainer groove closest to the second end of the retainer and a ball that is closest to the second end of the ball screw nut are spaced away from each other by a distance. The distance is set equal to or larger than the distance.

Ball screw device and steering system

A ball screw mechanism that allows a reduction in contact and friction between a retainer and a nut is provided. In a ball screw mechanism, a nut is threadedly engaged with a screw groove of a rack shaft through balls retained in a retainer groove of a retainer, and an axial force is applied to the rack shaft in accordance with rotation of the nut. The nut includes a uniform diameter portion having a uniform inside diameter and enlarged diameter portions each having an inside diameter larger than that of the uniform diameter portion. The enlarged diameter portions are provided at opposite axial ends of a region on an inner circumferential surface of the nut. The region faces the retainer groove and retainer ends adjoining to opposite axial ends of the retainer groove.

Ball screw mechanism and steering system

A ball screw device and a steering system that include a retainer having more uniform stiffness are provided. Between a rack shaft and a ball screw nut, a cylindrical retainer having a plurality of retainer grooves that retain balls in a rollable manner is provided. Each retainer groove has two short inner surfaces that intersect the extending direction of the retainer groove and two long inner surfaces that intersect these short inner surfaces and extend along the extending direction of the retainer groove. In each of interior-angle portions where the short inner surfaces and the long inner surfaces intersect, a corner round surface is formed. The radius of the corner round surface is set to be smaller than one half of the width of the retainer groove.

There is provided a steering apparatus including a fixing mechanism for fixing a driven pulley and a rolling nut to each other, the fixing mechanism configured to suppress at least one of deformation of external teeth of the driven pulley and an increase in size of a housing surrounding the driven pulley. A steering apparatus includes: a steered shaft; a ball screw mechanism including a rolling screw portion, a rolling nut, and rolling elements; a motor; a belt transmission mechanism including a drive pulley, a driven pulley, and a toothed belt; and a fixing mechanism. The fixing mechanism includes an internal thread, a cutout section, and a locknut. The cutout section is provided at a position offset, in the axial direction, from a range of second external teeth in the axial direction, and the locknut includes a locknut body, a locking lug, and a remaining portion.

Steering apparatus

A ball screw device is provided, including a retainer that can properly retain balls. The difference between a diameter being the pitch circle diameter of the ball screw device and the outside diameter of the rack shaft is set to be equal to or larger than the difference between the bore diameter of a ball screw nut and the diameter. The thickness center diameter of the retainer is set to be smaller than the diameter. Even when the inclination angle is reduced, the clearance between the inclined surfaces of each retainer groove on the radial inside can be easily set to be smaller than the diameter of the balls because the bore diameter of the retainer is set to be smaller. Thus, even when the inclination angle of the inclined surfaces is set to be smaller, the balls can be properly retained.

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.

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Okazaki, Japan

Takuya Nakayama