Synthetic resin-made sliding bearing

A synthetic resin-made sliding bearing comprising:

• a synthetic resin-made upper casing, a reinforced synthetic resin-made lower casing superposed on said upper casing so as to be rotatable about an axis in a circumferential direction relative to said upper casing, and a synthetic resin-made sliding bearing piece disposed between said upper casing and said lower casing,
• wherein said upper casing includes:
• an upper casing base portion having an annular lower surface in a vertical direction;
• an inner peripheral-side cylindrical suspended portion suspended from a radial inner peripheral end portion of the upper casing base portion;
• an outer peripheral-side cylindrical suspended portion suspended from a radial outer peripheral end portion of the upper casing base portion;
• an annular collar portion extending radially outwardly from a lower end portion of the outer peripheral-side cylindrical suspended portion;
• an inner annular protrusion which has a cylindrical inner peripheral surface continuously connected to a cylindrical inner peripheral surface of the outer peripheral-side cylindrical suspended portion and is suspended downwardly from an annular lower surface of the annular collar portion;
• an outer annular protrusion which is suspended downwardly from the annular lower surface of the annular collar portion to form an inner peripheral upper annular recessed portion radially outwardly in cooperation with the inner annular protrusion;
• and an engaging suspended portion which is suspended from an outer peripheral edge portion of the annular collar portion to form an outer peripheral upper annular recessed portion radially inwardly in cooperation with the outer annular protrusion, and which has on an inner peripheral surface thereof an engaging bulged portion which bulges radially inwardly,
• wherein said lower casing includes:
• an annular lower casing base portion having an annular upper surface and an annular lower surface in the vertical direction;
• a cylindrical protruding portion which protrudes downwardly from the annular lower surface of the lower casing base portion and has a cylindrical inner peripheral surface continuously connected to a cylindrical inner peripheral surface of the lower casing base portion;
• an annular protruding portion which protrudes upwardly from the annular upper surface of the lower casing base portion and has a cylindrical outer peripheral surface continuously connected to a cylindrical outer peripheral surface of the lower casing base portion;
• an annular collar portion which extends radially outwardly from a lower end portion of the cylindrical outer peripheral surface of the lower casing base portion;
• at least one projecting portion which projects radially outwardly from the cylindrical outer peripheral surface of the lower casing base portion and extends upwardly from an annular upper surface of the annular collar portion;
• an annular protrusion protruding upwardly from the annular upper surface of the annular collar portion to form an inner peripheral lower annular recessed portion in cooperation with cylindrical outer peripheral surface of the lower casing base portion;
• an engaging protruding portion which protrudes upwardly from the annular upper surface of the annular collar portion to form an outer peripheral lower annular recessed portion radially inwardly in cooperation with the annular protrusion, and which has an engaged bulged portion bulging radially outwardly from an outer peripheral surface thereof;
• and an annular plate portion extending radially outwardly from an outer peripheral-side lower end portion of the annular collar portion, and
• wherein said sliding bearing piece includes:
• an annular thrust sliding bearing piece portion having an annular upper surface and an annular lower surface in the vertical direction;
• a cylindrical radial sliding bearing piece portion which is suspended from an outer peripheral end portion of the thrust sliding bearing piece portion and has a cylindrical inner peripheral surface and a cylindrical outer peripheral surface;
• and a corrugated meshing portion having projecting portions and indented portions which are alternately formed along the circumferential direction on a lower portion of the cylindrical inner peripheral surface of the radial sliding bearing piece portion,
• said sliding bearing piece being disposed between said upper casing and said lower casing such that the annular lower surface of the thrust sliding bearing piece portion is brought into contact with the annular upper surface of the annular protruding portion of said lower casing, and the cylindrical inner peripheral surface of the radial sliding bearing piece portion is brought into contact with the cylindrical inner peripheral surface of the annular protruding portion of said lower casing, and such that the indented portion of the corrugated meshing portion is meshed with the projecting portion of said lower casing so that said sliding bearing piece is prevented from rotating about the axis with respect to said lower casing,
• said upper casing being combined with said lower casing such that the annular lower surface of the upper casing base portion is brought into slidable contact with the annular upper surface of the thrust sliding bearing piece portion, and the cylindrical inner peripheral surface of the outer peripheral-side cylindrical suspended portion is brought into slidable contact with the cylindrical outer peripheral surface of the radial sliding bearing piece portion, and such that the inner annular protrusion and the outer annular protrusion are respectively opposed to the inner peripheral lower annular recessed portion of said lower casing and the outer peripheral lower annular recessed portion of said lower casing, and the engaging bulged portion of the engaging suspended portion is resiliently fitted to the engaged bulged portion of the engaging protruding portion of said lower casing.