Detector and detecting system
A detector is a detector that detects fastening axial force applied by a fastening unit in an axial direction. The detector includes a strain element that has a through hole through which a bolt portion that the fastening unit has is inserted, and a strain sensing sensor that senses strain of the strain element. The strain element has a block-like form and has a planar portion following the axial direction on a side face thereof. The strain sensing sensor is provided on the planar portion.
1 . A detector that detects fastening axial force applied by a fastening unit in an axial direction, the detector comprising:
a strain element that has a through hole through which a bolt portion that the fastening unit has is inserted, the strain element having a planar portion at a side thereof, the planar portion extending along the axial direction and a first direction perpendicular to the axial direction, the planar portion having a center line extending along the first direction;
a strain sensing sensor that senses strain of the strain element, the strain sensing sensor being disposed on the planar portion of the strain element; and
an antenna disposed on the planar portion of the strain element to overlap and align with the strain sensing sensor along a second direction perpendicular to each of the axial direction and the first direction,
wherein the strain sensing sensor is configured with first, second, third, and fourth strain detecting elements,
the first and second strain detecting elements are aligned along a first linear line parallel to the first direction, and each of the first and second strain detecting elements is located closer to a bottom of the strain element than each of the third and fourth strain detecting elements and the center line of the planar portion,
the third and fourth strain detecting elements are aligned along a second linear line parallel to the axial direction, and
the third and fourth strain detecting elements are arranged so as to sandwich the center line of the planar portion along the second linear line.
2 . The detector according to claim 1 , wherein the strain element has a planar receiving portion at an upper face thereof and surrounds the through hole, and
the planar receiving portion receives a fastening member that the fastening unit has.
3 . The detector according to claim 1 , further comprising:
a control circuit.
4 . The detector according to claim 3 , wherein the control circuit is provided on the planar portion.
5 . The detector according to claim 1 , further comprising:
a sealing resin that seals the planar portion.
6 . The detector according to claim 1 , the further comprising:
a protruding portion provided on an end portion toward a side of a bottom face of the strain element, the protruding portion being formed in a flange-like form outwardly extending from an outer circumference of the end portion along a radial direction with respect to the axial direction.
7 . The detector according to claim 6 , further comprising:
a sealing resin that seals the protruding portion.