Jtekt Corporation

Oiles Corporation

Arata Kikuchi

Wataru Yamada

Hirotsugu Kusano

Yoshitomo Nagai

Takashi Horiguchi

Shuichi Kubota

Susumu Imagaki

Katsunori Saito

Yasutaka Fukumoto

Jun Hamakita

Hirotsugo Kusano

Yoshimoto Nagai

A power transmission coupling that couples an output shaft of an electric motor and a worm shaft together includes a first rotation element coupled to the output shaft, a second rotation element coupled to the worm shaft, and an intermediate element formed of an elastic body and interposed between the first rotation element and the second rotation element. The intermediate element forms a unit integrally including an annular support portion, power transmission portions extending radially from the support portion and interposed between engaging protrusions of the first rotation element and the second rotation element, a spacer arranged inward of the support portion in a radial direction to apply a preload to the worm shaft in an axial direction, and a coupling portion that couples the support portion and the spacer together.

Electric power steering system

A worm reduction gear satisfies following relational Formula (1) and Formula (2):3&#x2267;2/1&#x2267;1.7&#x2003;&#x2003;(1)0.1&#xb0;&#x2266;&#x3b1;&#x2212;&#x3b2;&#x2266;0.5&#xb0;&#x2003;&#x2003;(2)where Dis an outside diameter of a worm, Dis an outside diameter of a hob for cutting a worm wheel to form tooth spaces, and &#x3b1; is a pressure angle of the worm wheel and &#x3b2; is a pressure angle of the worm at an intermeshing pitch circle of the worm and the worm wheel.

Worm reduction gear and steering system

A center axis of a worm shaft is offset in an offset direction with respect to a plane that is orthogonal to a center axis of a worm wheel and that passes through a central position of the worm wheel in a tooth width direction. A bias member biases a second end of the worm shaft in a preloading direction in which a center distance between the worm shaft and the worm wheel decreases. When the worm shaft is configured like a right-hand thread, in a left-handed coordinate system, a direction toward a first end of the worm shaft in an axial direction (a direction toward an electric motor) corresponds to a thumb direction. The preloading direction corresponds to an index finger direction. The offset direction corresponds to a middle finger direction.

Worm speed reducer

An electric power steering device includes a worm which is swingably connected to the rotation shaft of an electric motor through a joint. A first end portion and second end portion of the worm are supported by a first bearing and a second bearing, respectively. A pair of elastic members elastically urge the worm to an axial neutral position. An annular leaf spring which is held by a housing urges the second end portion toward a worm wheel through the second bearing. A synthetic resin member having a sliding contact surface which is in contact with the leaf spring is integrally disposed on the second bearing.

Electric power steering device

An electric power steering system includes a joint that connects a rotary shaft of an electric motor with a worm shaft of a speed reducer. The joint includes a first rotational element that has a boss into which a first end portion of the worm shaft is press-fitted, and a flange extending radially from the boss. The first bearing is held by a housing and supports the first end portion so that the first end portion is rotatable and movable in an axial direction. A first elastic body, which urges the worm shaft in the axial direction toward the electric motor through the first rotational element, is provided between an inner ring of the first bearing and the flange.

In a speed reducer of an electric power steering system, a first bearing supports a first end portion of a worm so that the first end portion is movable in an axial direction. Elastic members elastically support the worm in the axial direction. A second bearing supports a second end portion of the worm. An urging member oscillates and urges the worm. The sum of first frictional resistance in the axial direction between an inner ring of the first bearing and the worm and second frictional resistance in the axial direction between the urging member and an outer circumference of an outer ring of the second bearing is less than engagement frictional resistance in the axial direction of the worm.

A gear includes a metal core and a synthetic resin tooth body. The metal core includes a cylindrical portion, and a disc portion that extends inwardly in a radial direction from one end of the cylindrical portion. The synthetic resin tooth body is coupled to the cylindrical portion of the metal core. A plurality of rotation prevention grooves is formed on the outer peripheral portion of the cylindrical portion, and a plurality of rotation prevention grooves is formed on the inner peripheral portion of the cylindrical portion.

Gear and electric power steering device

A shaft coupling mechanism includes a coupling base body coupled to a rotating shaft; a coupling base body coupled to a steering shaft; rotation transmitting members which are disposed between the rotating shaft and the steering shaft through the both coupling base bodies and transmit the rotation of the rotating shaft in an R direction to the steering shaft; an intermediate interposed member disposed between the rotation transmitting members; and a coupling means for coupling the rotation transmitting members to each other.

Growing community of inventors

Soraku-gun, Japan

Arata Kikuchi