Patent ID: 8066435

Claim:
A strut sliding bearing comprising: an upper casing made of a synthetic resin and having an annular lower surface; a lower casing which is made of a synthetic resin, is superposed on said upper casing so as to be rotatable about an axis of said upper casing, and has an annular upper surface opposed to the annular lower surface of said upper casing; and an annular thrust sliding bearing piece which is made of a synthetic resin, and is interposed between the annular lower surface of the upper casing and the annular upper surface of the lower casing, said annular thrust sliding bearing piece having an upper surface which is in slidable contact with the annular lower surface of the upper casing, and a lower surface which is in slidable contact with the annular upper surface of the lower casing, wherein said lower casing is configured in one-piece and has on a lower surface thereof a spring seat surface for a suspension coil spring, said lower casing includes an annular base portion, an upper cylindrical portion which is integrally formed on a radially substantially central portion of an upper surface of the annular base portion and on which the annular upper surface of the lower casing is formed, said upper cylindrical portion having an outer peripheral cylindrical surface with a diameter that is smaller than a diameter of an outer peripheral annular surface of the annular base portion, and said upper cylindrical portion having an inner peripheral cylindrical surface with a diameter that is larger than an inner peripheral annular surface of the annular base portion, and a lower cylindrical portion which is integrally formed on a radially substantially central portion of a lower surface of the annular base portion, said lower cylindrical portion having an outer peripheral cylindrical surface with a diameter that is smaller than the diameter of the outer peripheral annular surface of the annular base portion, and said lower cylindrical portion having an inner peripheral cylindrical surface with a diameter that is larger than the diameter of the inner peripheral annular surface of the annular base portion, said lower surface of the annular base portion on a radially outer side of the lower cylindrical portion serving as the spring seat surface, the annular base portion, the upper cylindrical portion, and the lower cylindrical portion including a plurality of thinning cavities, each of which opens externally at said lower surface of the annular base portion or a lower surface of the lower cylindrical portion.