Linear displacement sensor and linear displacement detecting system using electromagnetic induction

摘要

Provided in the present invention are a linear displacement sensor using an electromagnetic induction method and a linear displacement measuring system for a movable object using the same, which can effectively detect the linear position of a movable object by adopting a simple mechanical composition and can be manufactured on a mass production basis at a low cost. The linear displacement sensor comprises: a core; an input coil which is wound at one side of the core, and forms a time-varying magnetic field by being supplied with a time-varying current; an output coil which is placed in parallel with the input coil at a fixed interval, and induces voltage by being influenced by the time-varying current; and a translator including an electric conductor which performs a relative straight-line motion along with the input and output coils inside the time-varying magnetic field formed around the input coil. The translator is a trapezoidal plate shaped structure where the straight-ling motion direction is a long side direction, and the vertical direction to the straight-ling motion direction is a short side direction. In the translator, two facing sides in the short side direction are in parallel to each other; one side between facing two sides in the long side direction is vertical to the two sides in the short side direction; the other side between facing two sides in the long side direction has a shape where a gradient thereof changes in a linear or a constant function form as going from one end to the other end. Therefore, the linear displacement sensor can measure the displacement of a straight-line movement of the movable object by measuring changes in the voltage in the output coil depending on the changes in the area of the translator inside the time-varying magnetic field during the relative straight-line motion of the translator and the input and output coils.