Actuator, valve device, and fluid control apparatus

An actuator, comprising:

• a casing;
• a stem provided in the casing;
• a piezoelectric element supported by the casing to be displaced toward the stem;
• and
• a displacement amplification mechanism configured to amplify displacement of the piezoelectric element, wherein
• the displacement amplification mechanism includes a first lever portion, an intermediate member, and a second lever portion;
• the first lever portion is located between the piezoelectric element and the intermediate member and includes a first point-of-effort portion configured to receive displacement from the piezoelectric element, a first fulcrum portion which is in contact with the casing and becomes a center of rotational movement of the first lever portion, and a first point-of-load portion configured to transmit displacement to the intermediate member;
• the intermediate member is located between the first lever portion and the second lever portion and is configured to be displaced toward the second lever portion upon receipt of displacement from the first lever portion;
• and
• the second lever portion has a second point-of-effort portion configured to receive displacement from the intermediate member, a second fulcrum portion which is in contact with the casing and becomes the center of rotational movement of the second lever portion, and a second point-of-load portion configured to transmit the displacement to the stem;
• the first point-of-effort portion is located between the first fulcrum portion and the first point-of-load portion in a direction orthogonal to an axis of the stem;
• the second fulcrum portion is located between the second point-of-effort portion and the second point-of-load portion in the direction orthogonal to the axis of the stem;
• a distance between the second fulcrum portion and the second point-of-load portion is configured longer than a distance between the second fulcrum portion and the second point-of-effort portion;
• and
• the second point-of-load portion of the second lever portion is displaced toward the stem and moves the stem toward the piezoelectric element by means of displacement of the intermediate member to the second lever portion side.