Female threaded body, and threaded body fastening structure

A female threaded body comprising:

• a first female threaded helical structure formed on an inner circumferential surface of a hole of a cylindrical member, and set at a lead angle and/or in a lead direction;
• a reverse rotation-preventing member disposed in the cylindrical member, including a protruding portion extended in a radially inward direction towards an axis of the hole, and configured to prevent a rotation by the first female threaded helical structure at a predetermined circumferential angle by a protruding end of the protruding portion;
• and
• a deformable tapered surface formed on an end surface on another side of the cylindrical member,
• wherein, when being in contact with a male thread and elastically deformed, the protruding potion allows a relative rotation of the first female helical structure and the male thread in one direction and prevents a relative rotation of the first female threaded helical structure and the male thread in another direction to control a reverse rotation.

A threaded body fastening structure comprising:

• a male threaded body;
• and
• a female threaded body to be screwed with the male threaded body,
• wherein the male threaded body comprises:
• a head portion;
• and
• an axis portion including a first male threaded helical structure set at a lead angle and/or in a lead direction, and
• the female threaded body comprises:
• a first female threaded helical structure formed on an inner circumferential surface of a hole of a cylindrical member and set at a lead angle and/or in a lead direction to be screwed with the first male threaded helical structure;
• and
• a reverse rotation-preventing member disposed in the cylindrical member, including a protruding portion extended in a radially inward direction towards an axis, and configured to prevent a rotation by the first female threaded helical structure at a predetermined circumferential angle by a protruding end of the protruding portion,
• wherein a deformable tapered surface is formed on an end surface of the head portion of the male threaded body and/or an end surface of the cylindrical member of the female threaded body, and
• an engaging edge of the female threaded body comes into contact with the male threaded body and is elastically displaced to allow a relative rotation of the first male threaded helical structure and the first female threaded helical structure in one direction and prevent a relative rotation of the first male threaded helical structure and the first female threaded helical structure in another direction to control a reverse rotation.