Force sensor

A force sensor for detecting at least one of a force in each axial direction and a moment about each axis of a Cartesian coordinate system including a first axis, a second axis, and a third axis orthogonal to each other, the force sensor comprising:

• a first structure being a hollow cylinderical structure formed in such a way that the third axis passes therethrough;
• four strain generation parts each extending radially from the first strucutre along the first axis and the second axis on a reference plane formed by the first axis and the second axis;
• a second structure surrounding the first strucutre and connected to the first structure with the strain generation parts interposed therebetween, wherein
• each of the strain generation parts comprises a first connection part connected to the first structure, a first branch part, which is a pair of beam-like parts branching into two from the first connection part toward the second structure and extending in directions separating from each other, a second branch part, which is a pair of beam-like parts both connected to the first branch part with bent parts interposed therebetween and extending in directions approaching each other, and a second connection part where branched parts of the second branch part join and connects to the second structure, and
• the strain generation parts are and are formed in such a way that the strain generation parts become line-symmetric with respect to both the first axis and the second axis when the strain generation parts are projected in a direction perpendicular to the reference plane.