Torque sensor

A torque sensor for being attached around a magnetostrictive rotating shaft to measure torque applied to the rotating shaft, the torque sensor comprising:

• a non-magnetic bobbin that is provided coaxially with and at a distance from the rotating shaft, is formed into a hollow cylindrical shape, and comprises a plurality of first inclined guide paths and a plurality of second inclined guide paths on the outer peripheral surface, the first inclined guide paths being inclined at a predetermined angle relative to an axial direction and the second inclined guide paths being inclined at the predetermined angle relative to the axial direction in a direction opposite to the first inclined guide paths;
• first and fourth detection coils formed by winding insulated wires around the bobbin along the first inclined guide paths;
• and
• second and third detection coils formed by winding insulated wires around the bobbin along the second inclined guide paths,
• wherein the first to fourth detection coils each form a plurality of layers laminated on the outer surface of the bobbin, and a bridge circuit is formed by annularly connecting the first detection coil, the second detection coil, the fourth detection coil and the third detection coil in this order,
• wherein the layers of the second and third detection coils are interposed between the plurality of layers of the first detection coil,
• wherein the layers of the first and fourth detection coils are interposed between the plurality of layers of the second detection coil,
• wherein the layers of the first and fourth detection coils are interposed between the plurality of layers of the third detection coil, and
• wherein the layers of the second and third detection coils are interposed between the plurality of layers of the fourth detection coil.