Abstract: This rotation-linear motion conversion apparatus (10) includes: a pinion shaft (20) in which a pinion gear (22) is formed; a rack bar (30) in which a rack gear (32) that engages with the pinion gear (22) and a support surface (31) along a longitudinal direction are formed; and a support part (40) that supports the rack bar (30) movably along the support surface (31). The support part (40) prevents a movement of the rack bar (30) in a direction X perpendicular to a surface (30a) in which the rack gear (32) is formed.

Abstract: This rotation-linear motion conversion apparatus (10) includes: a pinion shaft (20) in which a pinion gear (22) is formed; a rack bar (30) in which a rack gear (32) that engages with the pinion gear (22) and a support surface (31) along a longitudinal direction are formed; and a support part (40) that supports the rack bar (30) movably along the support surface (31). The support part (40) prevents a movement of the rack bar (30) in a direction X perpendicular to a surface (30a) in which the rack gear (32) is formed.

Abstract: A screw device manufacturing method ensures high productivity and adequate nut strength. The disclosed screw shaft manufacturing method includes: a groove forming step of forming a loaded ball rolling groove in a flat plate; and a nut forming step of bending the flat plate into a ring to form a nut. As the groove forming step of forming of the loaded ball rolling in the flat plate is followed by the nut forming step of bending the flat plate into a ring, sufficient strength of the nut can be easily achieved. Besides, a high compression stress is left in the loaded ball rolling groove in the inner surface of the nut.

Abstract: A ball screw device having a novel ball circulation structure suitable for a screw shaft with a large lead, optimum for downsizing and weight saving of a nut member, capable of being manufactured at low cost, and capable of exhibiting high reliability even under severe use conditions. In a ball screw device where a screw shaft and a nut member are screwed to each other through an intermediation of a large number of balls, a no-load ball path which forms an infinite circulation path for the balls is constituted by a no-load ball groove spirally formed in an inner peripheral surface of a through-hole of the nut member and by a pair of direction change grooves which communicatively couple a load rolling groove and the no-load ball groove to each other so as to complete the infinite circulation path as a closed loop.

Abstract: A rolling guiding device makes it possible to easily provide a movement block with an endless circulation path for the balls. In one surface of a movement block opposed to a rolling groove of a raceway rail, there is formed a track groove through which balls makes an endless circulation. The track groove is includes a load straight-line groove which allows, between the track groove and the rolling groove of the raceway rail, the balls to roll while bearing a load. It also includes a pair of ball deflection grooves respectively provided at both ends of the load straight-line groove and adapted to release the balls having rolled through the straight-line groove from the load and to change their rolling direction, and a non-load straight-line groove for transferring the ball in a non-load state from one deflection groove to the other ball deflection groove.

Abstract: Provided is a ball screw device having a novel ball circulation structure suitable for a screw shaft with a large lead, optimum for downsizing and weight saving of a nut member, capable of being manufactured at low cost, and capable of exhibiting high reliability even under severe use conditions. In a ball screw device (1) where a screw shaft (2) and a nut member (3) are screwed to each other through an intermediation of a large number of balls (4), a no-load ball path (50) which forms an infinite circulation path for the balls (4) is constituted by a no-load ball groove (33a) spirally formed in an inner peripheral surface of a through-hole (30) of the nut member (3) and by a pair of direction change grooves (34) which communicatively couple a load rolling groove (20a) and the no-load ball groove (33a) to each other so as to complete the infinite circulation path as a closed loop.

Abstract: A method of producing a screw device, having high productivity and capable of achieving sufficient strength of a nut. The method of producing a screw device has a groove forming step for previously forming a load ball rolling groove in a flat plate, which step is followed by a nut forming step for forming a nut by bending the flat plate into a ring. Since the method has, after the groove forming step in which the load rolling groove is formed in the flat plate, the nut forming step in which the flat plate is bent into a ring, sufficient strength of the nut can be easily achieved, and in addition, high compression stress is left in the load ball rolling groove in the inner diameter surface of the nut.

Abstract: Provided is a steering device which can be reduced in size and weight and easily adapted even to a vehicle with a small engine room, such as a front-wheel-drive car.

Abstract: Provided is a novel steering device which can be formed to be compact, which is easily applicable to a vehicle with a small engine room such as a front-engine/front-drive car, and which is of neither the ball nut type nor the rack and pinion type. The steering device operates steerable wheels by converting rotation of a steering shaft to axial movement of a relay rod, the steering device including: a gear casing through which the relay rod is passed; a spiral ball rolling groove provided in the relay rod within the gear casing so as to exhibit a lead of a magnitude of 1 or more; a nut member threadedly engaged with the ball rolling groove of the relay rod through an intermediation of a large number of balls and supported rotatably with respect to the gear casing; an input shaft to which rotation of the steering shaft is transmitted and which is in an intersecting or offset relationship with the relay rod; and a first transmission gear for transmitting rotation of the input shaft to the nut member.

Abstract: Provided is a rolling guiding device which makes it possible to easily provide a movement block with an endless circulation path for the balls even in a case of a small-sized rolling guiding device using balls of a relatively small diameter and which can be produced easily and at low cost. In one surface of a movement block (2) opposed to a rolling groove (13) of a raceway rail (1), there is formed a track groove (21) through which balls (3) makes an endless circulation.

Abstract: A screw device is provided with a screw shaft 5 formed, on an outer peripheral surface thereof, with a ball member rolling groove 6 in form of spiral, a nut 1 formed, on an inner peripheral surface thereof, with at least single one-turn of groove 4 constituted by a loaded ball rolling groove 2 having a partial circle less than one circle of groove and corresponding to the ball rolling groove 6 of the screw shaft and a ball circulation groove 3 connecting one and other ends of the loaded ball rolling grove 2, and a plurality of balls arranged and accommodated between the ball rolling groove 6 of the screw shaft 5 and the loaded ball rolling groove 2 and the ball circulation groove 3 of the nut 1. The loaded ball rolling groove 2 and the ball circulation groove 3 of the nut 1 are formed by cutting the inner peripheral surface of the nut which was preliminarily heat-treated.