Patent ID: 7926826

Claim:
A load sensor device for a steering apparatus for detecting force applied to a wheel of a vehicle, the steering apparatus including: a connection link having a wheel-side end, which is connected with the wheel and freely inclined relative to the wheel, and a shaft-side end, which is movable substantially in a width direction of the vehicle for steering the wheel; and a first steering shaft including a steering shaft body, which is substantially in a rod shape extending substantially in the width direction of the vehicle, and a steering shaft end, which is fixed to one end of the steering shaft body and connected to the shaft-side end of the connection link, the steering shaft end being freely inclined relative to the shaft-side end, the first steering shaft being movable substantially in the width direction according to an operation of a steering device, the load sensor device comprising: a load sensor interposed between the steering shaft end and the steering shaft body and configured to detect load applied in an axial direction of the first steering shaft, the load sensor including: a load detection element applied with a preload in a compression direction in the axial direction of the first steering shaft; and a structural member having inner peripheries defining an inner space, which accommodates the load detection element, the load detection element has end portions interposed between the inner peripheries in the axial direction of the first steering shaft, the preload is set to be larger than (αx·sin θ/μ+αy·cos θ)·Ft, wherein Ft is an external force applied to the load sensor, θ is an inclination angle, at which the external force is applied, relative to the axial direction of the first steering shaft, αx is an element load assignment rate in the axial direction of the first steering shaft, αy is an element load assignment rate in a direction perpendicular to the axial direction of the first steering shaft, and μ is a coefficient of friction between the inner peripheries of the structural member and the load detection element.