Patent ID: 9455398
Filing Date: 2016-09-27
CPC Classification: F02M,F16K,G05D,H01L,Y10T

Claim Text:
1. A piezoelectric actuator, comprising: a piezoelectric element; a base body having an upper surface which is in contact with a lower end portion of the piezoelectric element; and a case having an inner surface which is in contact with an upper end portion of the piezoelectric element, the case storing the piezoelectric element therein, the upper surface of the base body and the case being joined to each other, the case including a cylindrical portion including a cylindrical main body and a plurality of grooves formed all around a perimeter thereof, and a collar portion disposed at a lower end side of the cylindrical portion, at least two or more of the plurality of grooves having a sectional profile taken along a plane perpendicular to a vertical direction whose oblate ratio differs from that of a sectional profile of the cylindrical main body, wherein the oblate ratio is a difference between a major radius and a minor radius divided by the major radius, and wherein the two or more of the plurality of grooves each having a sectional profile whose oblate ratio differs from that of the sectional profile of the cylindrical main body, vary in terms of orientation of a major axis of the sectional profile.