To simultaneously perform palpation on an object to be measured and the measurement of the degree of hardness, and at the same time, minimize the measurement error.
This hardness sensor consists of a main body A composed of a piezoelectric ceramic, the surface treated to form an electrode of which is formed into a circular and electostriction-type ultrasonic vibrator 1 vibrating radially. In addition, a disc-shaped common electrode 3 comprising a conductor is interposed between the ultrasonic vibrator 1 and a circular detection vibrator 2 which detects the vibration of the ultrasonic vibrator 1, and the ultrasonic vibrator 1, the detection vibrator 2 and the common electrode 3 are integrally stacked in the center axial direction. Further, a contact element 4 which comes into contact with an object M is junctioned to the common electrode 3.
IDE KAZUHIRO
SHIMIZU KEISUKE
OKUMURA REIKO
