Ngk Insulators, Inc.

Yasushi Ohkawa

Itsushi Nakamura

Tomio Suzuki

Eiji Kitagami

A polymer SP insulator comprising an FRP core, a sheathhaving a plurality of shedsprovided on outer periphery of FRP core, and metal-end-fittingscrimped to upper and lower ends of FRP core, in which a flat platefor adjusting the overall length dimension after crimping the metal-end-fittingis assembled in the inner bottom of the metal-end-fitting, and the overall length dimension is uniformly adjusted by the thickness of the flat plate. Further, a stress concentration portion such as cross groove is provided in the outer bottom of the lower Metal-end-fitting, and prevents instability by deformation of flangewhen crimping the Metal-end-fitting. In this configuration, in spite of the structure of crimping metal-end-fittings at upper and lower ends of the FRP core, the overall length tolerance, parallelism and eccentricity can be suppressed. In order to assure the flashover distance economically, preferably, the diameter of sheds of at least highest position and lowest position is larger than the diameter of intermediate shed.

Polymer SP insulator

A securing method of a polymer insulator including the steps of inserting an FRP core into a depression portion of a metal member having an open end portion, and connecting the metal member to the FRP core by compressing the FRP core and the metal member is disclosed. The improvement includes the steps of: determining a first region defining a part of a compression portion of the metal member, to which a compression pressure is applied, from a side of the open end portion; determining a second region defining the other part of the compression portion in succession with the first region; and controlling a deformation of the first region in such a manner that a deformation amount of the first region is increased gradually toward the second region.

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Nagoya, Japan

Yasushi Ohkawa