Internal thread member, external thread member, and cutter for internal thread

摘要

The present invention provides an internal thread member and an external thread member that can achieve stable finishing accuracy, can assure a desirable thread overlap, and have sufficient breaking strength and pullout strength. This invention also provides a cutter which can machine internal threads with stable finishing accuracy and can assure improved durability. An internal thread member 1 has an internal thread 10 that engages with an external thread 20 formed on an external thread member 2, and its height of thread engagement on the external thread side with reference to its pitch diameter is larger than the height of thread engagement on the internal thread side. The external thread member 2 has an external thread 20 that engages with the internal thread 10 formed on the internal thread member 1, and its height of thread engagement on the external thread side with reference to its pitch diameter is larger than the height of thread engagement on the internal thread side. The cutter comprises: a thread crest 23 in the shape complimentary to that of a thread root 11 of the internal thread 10; and flanks 22A and 22B in the shapes complimentary to those of flanks 12A and 12B of the internal thread 10.