US 12,281,730 B2
Tube fitting
Toshihide Iida, Osaka (JP); Kenji Onishi, Osaka (JP); Hiroki Tanabe, Osaka (JP); Yu Notoji, Osaka (JP); and Shohei Minamihara, Osaka (JP)
Assigned to NIPPON PILLAR PACKING CO., LTD., Osaka (JP)
Appl. No. 18/259,656
Filed by NIPPON PILLAR PACKING CO., LTD., Osaka (JP)
PCT Filed Nov. 22, 2021, PCT No. PCT/JP2021/042748
§ 371(c)(1), (2) Date Jun. 28, 2023,
PCT Pub. No. WO2022/180958, PCT Pub. Date Sep. 1, 2022.
Claims priority of application No. 2021-029873 (JP), filed on Feb. 26, 2021.
Prior Publication US 2024/0003469 A1, Jan. 4, 2024
Int. Cl. F16L 19/025 (2006.01)
CPC F16L 19/025 (2013.01) 2 Claims
OG exemplary drawing
 
1. A tube fitting that connects a first tube with a second tube, comprising:
a fitting body having a tubular shape whose first axial end portion includes a connector for the first tube, and whose second axial end portion includes an annular groove;
a sleeve whose first axial end portion includes an annular protrusion and an external thread, and whose second axial end portion includes a connector for the second tube; and
a nut including an internal thread to be engaged with the external thread, wherein:
engagement of the external thread with the internal thread causes press-fit of the annular protrusion into the annular groove to form a seal region between the annular protrusion and the annular groove;
under a condition that a depth of the annular groove is three or more times as large as a thickness of a radially inward or outward wall of the annular groove, an axial distance from the seal region to a bottom of the annular groove is designed to exceed ten times an increment width of the annular groove caused by the press-fit of the annular protrusion into the annular groove; and
the nut is integrated as a single piece with the second axial end portion of the fitting body.