A torque sensor device disposed between an input shaft and an output shaft and configured to detect a torque between the input shaft and the output shaft through a relative rotation displacement therebetween, the torque sensor device comprising:
- a housing configured to accommodate an end of the input shaft and an end of the output shaft and fixed in position to be able to perform a relative rotation with respect to the input shaft and the output shaft:
- a magnet unit rotatably accommodated in the housing in such a manner as to be connected to one end of one of the input shaft and the output shaft;
- a collector unit rotatably accommodated in the housing in such a manner as to be at least partially connected to one end of the other of the input shaft and the output shaft, the collector unit being configured to form a magnetic circuit together with the magnet unit;
- and
- a sensing unit including a torque sensor disposed at the outer circumference of the collector unit and configured to detect a magnetic field focused by the collector unit,
- wherein the collector unit comprises a lower collector including an annular lower collector ring disposed radially and circumferentially at one end of the other of the input shaft and the output shaft,
- wherein the magnet unit comprises a magnet ring,
- wherein the collector unit further comprises;
- an upper collector disposed to be oriented toward one of the input shaft and the output shaft;
- a fixing collector fixed in position to the housing so as to be disposed at the outer circumferences of the upper collector and the lower collector in a spaced manner with the torque sensor interposed between one ends of the fixing collector, wherein the lower collector is disposed so as to be spaced apart from the upper collector,
- wherein the upper collector comprises:
- an annular upper collector ring disposed radially and circumferentially at one end of the other of the input shaft and the output shaft;
- and
- an upper collector tooth array composed of a plurality of upper collector teeth which are formed extending downwardly from an inner circumferential end of the upper collector ring in such a manner as to be circumferentially spaced apart from each other at equal angular intervals,
- wherein the lower collector further comprises a lower collector tooth array composed of a plurality of lower collector teeth which are formed extending radially from an inner circumferential end of the lower collector ring in such a manner as to be circumferentially spaced apart from each other at equal angular intervals,
- wherein one of the upper collector tooth array and the lower collector tooth array is formed in the axial longitudinal direction of the input shaft and the output shaft, and
- wherein the other of the upper collector tooth array and the lower collector tooth array is formed in the radial direction of the input shaft and the output shaft,
- wherein the upper collector tooth array is formed at the output shaft in the longitudinal direction of the output shaft,
- wherein the magnet ring is provided in pair, and the lengths of the two magnet rings in the axial longitudinal direction of the input shaft and the output shaft are different from each other,
- wherein the magnet ring comprises:
- an upper magnet ring disposed to correspond to the upper collector;
- and
- a lower magnet ring disposed to confront the lower collector,
- wherein N poles and S poles of each of the upper magnet ring and the lower magnet ring are alternately arranged in a circumferential direction, and
- wherein the aspect ratio (ARu) of the upper ring magnet is less than the aspect ratio (AB1) of the lower magnet ring with respect to the cross-section formed in the longitudinal direction of the input shaft and the output shaft.