Torque sensor

Abstract

Two coaxial circumferential grooves formed apart from each other in an axial direction are provided for a coil bobbin made of a non-conductive material, such as plastic, and arranged to be secured in a housing coaxially with an input shaft and an output shaft. Moreover, a torque detection coil is wound around each of the circumferential grooves. A terminal mounting portion is formed on the end surface of a connecting portion facing outwards in the radial direction to further outwardly project in the radial direction. Three metal terminals are secured to the upper surface of the terminal mounting portion. An end of one of the coils is wound around the first terminal, an end of the other coil is wound around the second terminal, and other ends of the two coils are wound around the third terminal. A yoke is composed of a first annular member for covering the outer surface and one of end surfaces of the coil and having an L-shape cross section, and a second annular member for covering another end surface of the coil and having a rectangular cross section. A portion of the first annular member for covering the outer surface of the coil also covers the outer surface of the second annular member, and the portion is provided with three cut portions having the same dimensions and formed at the same intervals in the circumferential direction. Each of the cut portions has dimensions with which it somewhat overlaps the outer surface of the coil. A terminal holding member having terminals for drawing the end of the coil to the outside is secured to the outer surface of the second annular member so as to be received in one of the three cut portions.