Jtekt Corporation

Koyo Bearings North America LLC

Gento Aramoto

Naoko Sakaguchi

Tomoya Yamatani

Tsuyoshi Okumura

Justin Brubaker

Kenichi Hamano

A ball screw device includes a screw shaft that has a first helical groove on an outer circumference, a nut that has a second helical groove on an inner circumference, a plurality of balls, a stopper provided at an end portion of the second helical groove, and a spring body that is placed between an end portion ball closest to the stopper and the stopper. The spring body is configured of a plurality of coil springs arrayed along the first helical groove and the second helical groove. The coil springs that are adjacent each have a spring end portion of which rigidity is higher than rigidity of a spring middle portion.

Ball screw device

A ball screw assembly having a ball nut including a first end, a second end, a central bore, and a ball track defined by the inner surface, a ball screw shaft including an outer surface defining a ball track, the ball screw shaft being disposed in the central bore so that the ball tracks form a ball raceway, a first stopper disposed within the ball raceway, a plurality of main balls forming a ball train, the ball train being disposed in the ball raceway, and a main spring assembly disposed in the ball raceway between a first end of the ball train and the first stopper, wherein a spring constant of the first spring portion is greater than a spring constant of the second spring portion.

Segmented spring for a ball screw

In a ball screw apparatus, a ball train including a plurality of main balls is housed in a raceway between a ball track of a ball nut and a ball track of a ball screw shaft. A coil spring housed in the raceway includes a first end that engages with an end of the ball train and a second end supported by a stopper (a first recessed portion, a protruding portion, or the like) of the ball nut. A stopper ball having a diameter larger than the diameter of the main ball is interposed between the stopper and the second end of the coil spring.

Ball screw apparatus

An actuator includes a motor, a first gear coupled to the motor, a second gear that meshes with the first gear, and a clutch. The clutch includes an outer ring and an inner ring. A plurality of wedge spaces are formed along a circumferential direction between an inner peripheral surface portion of the outer ring and an outer peripheral surface portion of the inner ring. The clutch further includes rolling elements provided in the wedge spaces. While a radial load is not applied to the outer ring, each rolling element does not engage with the outer peripheral surface portion or the inner peripheral surface portion, so that a clearance is generated. While the radial load is applied to the outer ring, each rolling element engages with the outer peripheral surface portion and the inner peripheral surface portion without the clearance.

Clutch and actuator including the same

Displacement of a switching member in a first direction causes rolling elements of each pair to come out of engagement with an outer peripheral portion or an inner peripheral portion and form clearances therewith, resulting in an OFF state of a driving force transmission apparatus. Displacement of the switching member in a second direction causes a downstream one of the rolling elements of each pair in the direction of rotation to come into zero clearance engagement with the outer peripheral portion and the inner peripheral portion, with a clearance formed between an upstream one of the rolling elements of each pair and the outer peripheral portion or the inner peripheral portion, resulting in an ON state of the driving force transmission apparatus.

Driving force transmission apparatus

A driving force transmission device includes an inner ring; an outer ring; a roller pair constituted by a first roller and a second roller; an elastic member; a first cage including a first pressing portion; a second cage including a second pressing portion; a first guide member; a second guide member; and an electromagnetic clutch including an armature connected to the first and second guide members. Along with rotation of the first cage toward the circumferential second side, the first pressing portion presses the first roller toward the circumferential second side. Along with rotation of the second cage toward the circumferential first side, the second pressing portion presses the second roller toward the circumferential first side.

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Osaka, Japan

Gento Aramoto