Koyo Seiko Company, Ltd.

Tatsuo Otsuka

Masanori Kobayashi

Yoshio Ito

Akihiko Shiina

Tetsuya Murakami

Takeo Iino

Takayuki Todaka

Osamu Sano

Susumu Imagaki

Kunihiro Oka

Shigetaka Kinme

Tatsuhiro Yamamoto

Tomoyuki Takei

On the outer periphery of a bearing for supporting a worm rotating interlocked with the rotation of a steering assist motor inside the housing , elastic members are provided to restrain the bearing from moving in the radial direction thereof. The force for the restraint by the elastic members is made different depending on the position in the peripheral direction thereof. A portion of the elastic member, wherein the force for restraining the movement of the bearing in the radial direction is small, energizes the worm to the meshing position of the worm and a worm wheel . Another portion, wherein the force for restraining the movement is large, restrains the worm from moving along the lead of the worm wheel . With this configuration, the elastic members can reduce the amount of the backlash at the meshing portion of the worm and the worm wheel , and can make the rotation torque applied to the meshing portion of the worm gears relatively small.

Electric power steering apparatus

An electric power steering apparatus in which a shaft of a worm interlocking with rotation of a motor for steering assistance is movable in a radial direction, a pressing body for pressing the worm toward a worm wheel is provided, and the pressing body is provided with a V-shaped contact portion to abut in two circumferential positions of the shaft and an annular elastic body for restricting movement of the pressing body in a direction crossing the radial direction.

On the outer periphery of a bearing for supporting a worm rotating interlocked with the rotation of a steering assist motor inside the housing elastic members are provided to restrain the bearing from moving in the radial direction thereof. The force for the restraint by the elastic members is made different depending on the position in the peripheral direction thereof. A portion of the elastic member, wherein the force for restraining the movement of the bearing in the radial direction is small, energizes the worm to the meshing position of the worm and a worm wheel Another portion, wherein the force for restraining the movement is large, restrains the worm from moving along the lead of the worm wheel With this configuration, the elastic members can reduce the amount of the backlash at the meshing portion of the worm and the worm wheel and can make the rotation torque applied to the meshing portion of the worm gears relatively small.

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Tondabayashi, Japan

Tatsuo Otsuka