Triaxial force sensor and triaxial force detection method

A triaxial force detection method for detecting force components in an X-axial direction, a Y-axial direction, and a Z-axial direction acting on a load action element, the method comprising:

• arranging a plurality of strain sensitive elements in the X-direction and in the Y-direction of a strain causing plate part, each of the plurality of strain sensitive elements in the X-direction and in the Y-direction being formed by a grid pattern of reciprocating straight lines;
• and
• detecting a force component in the X-axial direction by an X-axial bridge circuit using the strain sensitive elements in the X-axial direction;
• detecting a force component in the Y-axial direction by a Y-axial bridge circuit using the strain sensitive elements in the Y-axial direction;
• an entirety of the X-axial bridge circuit and an entirety of the Y-axial circuit being connected by a pair of opposite sides, respectively;
• and
• detecting a force component in the Z-axial direction by a Z-axial bridge circuit in which an output signal in accordance with a change in a combined resistance value of the X-axial bridge circuit and a change in a combined resistance value of the Y-axial bridge circuit.

A triaxial force sensor comprising:

• a protruding load action element provided on a center of one surface of a strain causing plate part;
• and
• a plurality of strain sensitive elements arranged on the other surface of the strain causing plate part for detecting strains in an X-axial direction, a Y-axial direction, and
• a Z-axial direction caused by a force acting on the load action element,
• wherein the same number of strain sensitive elements are arranged at one side and the other side in the X-axial direction relative to the center of the strain causing plate part, and the same number of the strain sensitive elements are arranged at one side and the other side in the Y-axial direction relative to the center of the strain causing plate part;
• thus an X-axial bridge circuit for detecting a component of force in the X-axial direction is formed with the strain sensitive elements arranged at the one side and the other side in the X-axial direction;
• and a Y-axial bridge circuit for detecting a component of force in the Y-axial direction is formed with the strain sensitive elements arranged at the one side and the other side in the Y-axial direction;
• and
• an entirety of the X-axial bridge circuit and an entirety of the Y-axial circuit being connected by a pair of opposite sides, respectively;
• and
• a Z-axial bridge circuit for detecting a component of force in the Z-axial direction by an output signal obtained in accordance with a change in a combined resistance value of the X-axial bridge circuit and a change in the combined resistance value of the Y-axial bridge circuit;
• a detection unit configured by arranging the strain sensitive elements in the strain causing plate part;
• a signal processing unit that processes output signals from the X-axial bridge circuit, the Y-axial bridge circuit and the Z-axial bridge circuit, wherein
• at least one of fixed resistive elements included in the X-axial bridge circuit, the Y-axial bridge circuit or the Z-axial bridge circuit is a fixed resistive element arranged in the signal processing unit;
• wherein the detection unit comprises
• a ring surrounding part formed along the outer circumference on the other surface of the strain causing plate part, and
• a gauge mount area defined inside the ring surrounding part.