Jtekt Corporation

Koyo Seiko Company, Ltd.

Wataru Yamada

Arata Kikuchi

Susumu Imagaki

Hirotsugu Kusano

Shigeo Kamamoto

Yoshiyuki Saito

Shuzo Hirakushi

Jun Hamakita

Ryuji Nakata

Hirotaka Yasuda

Yoshitomo Nagai

Shingo Ougita

Takayasu Yamazaki

Yuji Wakugawa

Atsuhiro Yoshida

Hideyuki Honkado

Hiroyuki Shigemura

Ryousuke Yamazaki

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

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 speed reducer for an electric power steering system includes a worm, a worm wheel, and a housing. Only a meshing section where the worm and the worm wheel mesh with each other and a space between the worm wheel and the housing are filled with grease. The grease in the space is in contact with both tooth surfaces of the worm wheel and an inner peripheral face of the housing, the inner peripheral face facing the worm wheel.

Speed reducer and electric power steering system

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

An electric power steering apparatus comprises a transmission mechanism having a drive gear and a driven gear. One end of the drive gear is supported by a bearing hole in a housing through a bearing and a curved plate spring. The curved plate spring comprises a main body surrounding the bearing and at least one crank-shaped elastic tongue supported by at least one of ends of the main body. A recess formed on an inner peripheral surface of the bearing hole has a bottom and a pair of inner wall surfaces opposed to each other in the circumferential direction of the bearing hole. A relief portion for avoiding contact with a connection portion of the elastic tongue is formed between at least one of the inner wall surfaces and the inner peripheral surface of the bearing hole. A boundary between the relief portion and the inner peripheral surface of the bearing hole is engaged with the main body of the curved plate spring, to restrict the movement of the main body in the circumferential direction.

Electric power steering apparatus

An electric power steering apparatus comprises a driving gear driven by an electric motor for steering assist and a driven gear meshed with the driving gear. A steering shaft is rotated along with the driven gear. The steering shaft is rotatably supported by a first bearing and a second bearing. An urging member is arranged in a recess provided in a housing. The urging member urges at least one of the first bearing and the second bearing in a direction in which a center-to-center distance between the driving gear and the driven gear increases.

Deep groove ball bearings are used as bearings supporting both side portions of a worm. In the first bearing on the side of a motor, the curvature radius of a raceway groove in an inner ring or the curvature radius of a raceway groove in an outer ring are set to a specific numerical range with respect to the diameter of a ball.

Worm support device and power assist unit having the same

A gear pump includes a pair of gears accommodated in a gear chamber. When the inside pressure of a trap region which is changed with the rotation of the gears becomes substantially equal to the inside pressure of an inlet chamber, the communication state is switched from a state in which communication between the trap region and the first and second relief channels is blocked to a state in which the trap region communicates with the second relief channel. With the inside pressure of the trap region being substantially equal to the inside pressure of the inlet chamber, the trap region is opened to the inlet chamber.

Growing community of inventors

Kashiwara, Japan

Wataru Yamada