Displacement sensor with a movable element shaped to provide a linear response curve
AssigneeTechno Excel Kabushiki Kaisha
InventorsShozo Miyazawa, Takanori Kobayashi
Life of this patent
Estimating the term…
Abstract
The present invention relates to a solenoid device such as a flow control valve and a displacement sensor. In a conventional solenoid device, it is not possible to get characteristic curve for easy control of the input voltage to an electromagnetic coil and the stroke of a plunger, or the stroke of a plunger and the frequency of a coil. Thus, it is difficult to control, land the stroke of the plunger is short. Therefore, in the present invention, the above stated disadvantages are solved by forming the end section of the plunger tapered, so that an electromagnetic valve having linear characteristic curve and longstroke plunger or a highly precise displacement sensor can be provided.
Claims5
A displacement sensor comprising a sensor body, an electromagnetic coil, said coil having an inward facing surface surrounding the central cavity thereof and an axial direction, an electric current supply means for supplying electric current to said coil, a plunger, said plunger being made of magnetizable material, being disposed within the central cavity of said coil, and being capable of moving in said axial direction of said coil, a displacement body, said displacement body being movable with movement of said displacement body causing proportional movement of said plunger along said axial direction, said coil reflecting the amount of displacement of said displacement body via the movement of said plunger by change of reactance, and a detection means for detecting the change of reactance of said coil as said plunger changes position along said axial direction, and
- wherein said plunger includes a middle section, said middle section having a predetermined width, an upper end section having an upper end face, a parallel peripheral surface, said parallel peripheral surface extending parallel to the longitudinal axis of said plunger from said middle section to intersect with said upper end face to form more than one portion of a peripheral edge of said upper end face.
Dependencies are inferred from the claim text.