Vehicle steering device

A vehicle steering system including an operating mechanism to which an operating member of a vehicle is connected, the operating member being configured to be operated to turn a steered wheel of the vehicle, the vehicle steering system comprising:

• a motor configured to generate torque for changing an operating force that is needed to operate the operating member;
• and
• a transmission mechanism configured to transmit the torque generated by the motor to the operating mechanism, wherein:
• the motor includes a motor housing that houses a stator and a rotor, and an output shaft configured to rotate with the rotor includes an output portion that protrudes from the motor housing to outside;
• the transmission mechanism includes a mechanism housing that houses part of the operating mechanism and that houses the output portion so as to connect the part of the operating mechanism to the output shaft;
• the motor is disposed such that an axis of the output shaft intersects with a horizontal direction and that the output portion protrudes from a lower side of the motor housing in a direction of gravity;
• the transmission mechanism is disposed so as to house the output portion from a lower side of the motor in the direction of gravity;
• the motor housing includes a motor-side fitting portion that is fitted in the mechanism housing in an axial direction of the output shaft;
• the mechanism housing includes a mechanism-side fitting portion that is fitted on the motor-side fitting portion in the axial direction;
• the motor-side fitting portion includes an extending portion disposed outward of the mechanism-side fitting portion in a radial direction of the output shaft when viewed from the axial direction, and the extending portion extends from the motor housing toward a lower side in the direction of gravity such that a position of the extending portion in the axial direction overlaps with the mechanism-side fitting portion;
• the motor housing includes a plurality of bolt fastening portions, the mechanism housing includes a plurality of bolt fastening portions, and the bolt fastening portion of the motor housing is fastened to an opposing one of the bolt fastening portions of the mechanism housing in the axial direction;
• the motor-side fitting portion includes a fitting protrusion extending from the motor housing toward the lower side in the direction of gravity at a position inward of the extending portion in the radial direction of the output shaft;
• the mechanism-side fitting portion includes a peripheral protruding portion extending from the mechanism housing toward an upper side in the direction of gravity at a position inward of the extending portion in the radial direction of the output shaft;
• an outer peripheral surface of the fitting protrusion and an inner peripheral surface of the peripheral protruding portion include contact surfaces that contact each other;
• and
• the plurality of bolt fastening portions is disposed inward of the contact surfaces in the radial direction of the output shaft.