Abstract: It is an object, in a wheel attachment unit holding a rotary encoder externally attached to a wheel, to certainly acquire an encoder output signal obtained from a rotating shaft of a tire, by reducing an occurrence of a bending deformation or breakage of a unit component (e.g., shaft) occurred during a vehicle run and making the encoder function normally. A shaft, through which there is passed a cable for outputting a measurement result of the encoder whose rotating shaft is connected to the wheel, is arranged offset from the axle center by a predetermined amount and is held by a bracket attached to the vehicle, to be movable in the up and down direction. Alternatively, a holder for holding a stator of the encoder is attached to the body of the vehicle, by a rotary linkage mechanism to hold rotatably with five degrees of rotational freedom.

Abstract: It is an object, in a wheel attachment unit holding a rotary encoder externally attached to a wheel, to certainly acquire an encoder output signal obtained from a rotating shaft of a tire, by reducing an occurrence of a bending deformation or breakage of a unit component (e.g., shaft) occurred during a vehicle run and making the encoder function normally. A shaft, through which there is passed a cable for outputting a measurement result of the encoder whose rotating shaft is connected to the wheel, is arranged offset from the axle center by a predetermined amount and is held by a bracket attached to the vehicle, to be movable in the up and down direction. Alternatively, a holder for holding a stator of the encoder is attached to the body of the vehicle, by a rotary linkage mechanism to hold rotatably with five degrees of rotational freedom.