Patent Number: 
Section: claims

1. A water lubricated composite thrust bearing of a nuclear main pump, comprising:a stainless steel base having an upper concave-convex surface and a lower concave-convex surface;an upper engineering plastic layer disposed on the upper concave-convex surface; anda lower engineering plastic layer disposed on the lower concave-convex surface, wherein a ratio of an area of the upper or the lower concave-convex surface to an area of an orthographic projection of the upper or the lower concave-convex surface on the stainless steel base ranges from 1.2 to 2,wherein a thickness of the upper engineering plastic layer is 2 to 15 mm, and a thickness of the lower engineering plastic layer is 0.5 to 5 mm,wherein at least one of the upper engineering plastic layer and the lower engineering layer is a composite engineering plastic layer comprising a modified layer and a non-modified layer fused together, the non-modified layer being bonded to the concave-convex surface,wherein the modified layer is made of modified polyether ether ketone or modified polyphthalazinone ether sulfone ketone, and the non-modified layer is made of polyether ether ketone or polyphthalazinone ether sulfone ketone, andwherein a thickness of the modified layer is ⅔ to ⅘ of a thickness of the composite engineering plastic layer. 2. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein a convex portion of at least one of the concave-convex surfaces is roughened by knurling using a knurl wheel having a pitch of about 0.3-1.5 mm. 3. The water lubricated composite thrust bearing of the nuclear main pump according to claim 2, wherein the stainless steel base is sector-shaped or circular; the concave surface of the concave-convex surface is composed of a plurality of annular grooves, the shape of the annular grooves being matched with the outer edge of the stainless steel base, the plurality of the annular grooves being arranged at equal intervals, a distance between the adjacent annular grooves being 6 to 10 mm, a width of a rabbet of the annular groove being 4 to 12 mm, a width of a bottom of the annular groove being 0.5 to 1 mm larger than the width of the rabbet of the annular groove, and a depth of the annular groove being 1 to 5 mm. 4. The water lubricated composite thrust bearing of the nuclear main pump according to claim 2, wherein the stainless steel base is sector-shaped or circular; the concave surface of the concave-convex surface is composed of a plurality of transverse grooves and a plurality of longitudinal grooves, the plurality of transverse grooves being arranged at equal intervals, a distance between the adjacent transverse grooves being 6 to 10 mm, a width of a rabbet of the transverse groove being 4 to 12 mm, a width of a bottom of the transverse groove being 0.5 to 1 mm larger than the width of the rabbet of the transverse groove, and a depth of the transverse groove being 1 to 5 mm; the plurality of longitudinal grooves being arranged at equal intervals, a distance between the adjacent longitudinal grooves being 6 to 10 mm, a width of a rabbet of the longitudinal groove being 4 to 12 mm, a width of a bottom of the longitudinal groove being 0.5 to 1 mm larger than the width of the rabbet of the longitudinal groove, and a depth of the longitudinal groove being 1 to 5 mm. 5. The water lubricated composite thrust bearing of the nuclear main pump according to claim 2, wherein the stainless steel base is sector-shaped; the concave surface of the concave-convex surface is composed of a plurality of arc-shaped grooves, the shape of the arc-shaped groove being matched with an arc of the sector, the plurality of the arc-shaped grooves being arranged at equal intervals along a radius direction of the sector, a distance between the adjacent arc-shaped grooves being 6 to 10 mm, a width of a rabbet of the arc-shaped groove being 4 to 12 mm, a width of a bottom of the arc-shaped groove being 0.5 to 1 mm larger than the width of the rabbet of the arc-shaped groove, and a depth of the arc-shaped groove being 1 to 5 mm. 6. The water lubricated composite thrust bearing of the nuclear main pump according to claim 2, wherein the stainless steel base is sector-shaped or circular, and the concave surface of the concave-convex surface is composed of a plurality of blind holes that are arranged in order, a distance between the adjacent blind holes being 6 to 10 mm, a diameter of an opening of the blind hole being 4 to 10 mm, a diameter of a bottom of the blind hole being 0.5 to 1 mm larger than the diameter of the opening of the blind hole, and a depth of the blind hole being 1 to 5 mm. 7. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein the stainless steel base is sector-shaped or circular; a concave surface of each of the concave-convex surfaces is composed of a plurality of annular grooves, the shape of the annular grooves being matched with the outer edge of the stainless steel base, the plurality of the annular grooves being arranged at equal intervals, a distance between the adjacent annular grooves being 6 to 10 mm, a width of a rabbet of the annular groove being 4 to 12 mm, a width of a bottom of the annular groove being 0.5 to 1 mm larger than the width of the rabbet of the annular groove, and a depth of the annular groove being 1 to 5 mm. 8. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein the stainless steel base is sector-shaped or circular; the concave surface of the concave-convex surface is composed of a plurality of transverse grooves and a plurality of longitudinal grooves, the plurality of transverse grooves being arranged at equal intervals, a distance between the adjacent transverse grooves being 6 to 10 mm, a width of a rabbet of the transverse groove being 4 to 12 mm, a width of a bottom of the transverse groove being 0.5 to 1 mm larger than the width of the rabbet of the transverse groove, and a depth of the transverse groove being 1 to 5 mm; the plurality of longitudinal grooves being arranged at equal intervals, a distance between the adjacent longitudinal grooves being 6 to 10 mm, a width of a rabbet of the longitudinal groove being 4 to 12 mm, a width of a bottom of the longitudinal groove being 0.5 to 1 mm larger than the width of the rabbet of the longitudinal groove, and a depth of the longitudinal groove being 1 to 5 mm. 9. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein the stainless steel base is sector-shaped; the concave surface of the concave-convex surface is composed of a plurality of arc-shaped grooves, the shape of the arc-shaped groove being matched with an arc of the sector, the plurality of the arc-shaped grooves being arranged at equal intervals along a radius direction of the sector, a distance between the adjacent arc-shaped grooves being 6 to 10 mm, a width of a rabbet of the arc-shaped groove being 4 to 12 mm, a width of a bottom of the arc-shaped groove being 0.5 to 1 mm larger than the width of the rabbet of the arc-shaped groove, and a depth of the arc-shaped groove being 1 to 5 mm. 10. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein the stainless steel base is sector-shaped or circular, and the concave surface of the concave-convex surface is composed of a plurality of blind holes that are arranged in order, a distance between the adjacent blind holes being 6 to 10 mm, a diameter of an opening of the blind hole being 4 to 10 mm, a diameter of a bottom of the blind hole being 0.5 to 1 mm larger than the diameter of the opening of the blind hole, and a depth of the blind hole being 1 to 5 mm. 11. The water lubricated composite thrust bearing of the nuclear main pump according to claim 1, wherein the modified layer is made of modified polyphthalazinone ether sulfone ketone, and the non-modified layer is made of polyphthalazinone ether sulfone ketone.