Bite-in type pipe connection structure, valve, bite-in type pipe joint, and refrigeration device

A bite-in type pipe connection structure comprising:

• a joint body having a cam surface;
• an annular ferrule formed to have a tapered surface with an outer circumferential surface that becomes wider in a direction opposite to the cam surface, the ferrule having at a center a pipe insertion hole through which a pipe to be connected is passed through;
• and a coupling member that is fastened to the joint body to press the ferrule against the cam surface of the joint body, the pipe connection structure being characterized in that:
• the ferrule includes:
• a low-strength portion for deforming a distal end portion of the ferrule so that the distal end portion restrains a pipe to be connected when the coupling member is manually rotated to be fastened to the joint body;
• a level changing portion connecting a first tapered surface and a second tapered surface of the tapered surface to each other, the first tapered surface corresponding to the low-strength portion and the second tapered surface being farther from the cam surface than the first tapered surface is;
• and an adjacent portion that adjoins the low-strength portion from a side opposite to the cam surface, the adjacent portion airtightly retaining the pipe to be connected when the coupling member is fastened to the joint body, and
• the outer diameter of the tapered surface at the boundary between the level changing portion and the second tapered surface is greater than the outer diameter of the tapered surface at the boundary between the level changing portion and the first tapered surface, and the level changing portion is formed such that the thickness of the adjacent portion has a value capable of airtightly retaining the pipe to be connected.