Patent ID: 11879572
Assignee: SANOH INDUSTRIAL CO., LTD.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  B | IPC B  F

Claim 18:
19. The tube fitting according to claim 1, wherein:
the tube is a brake tube that is employed as a brake conduit for an automobile;
when a testing member corresponding to the mating member and a testing tube having a same outer diameter as the tube and having a testing annular portion corresponding to the annular portion are prepared, and a fastening test is repeated n times (where 1<n<6), the fastening test including: fastening operation to fasten the tube fitting to the testing member with a tightening torque in a range of 12.0 to 22.0 Nm, in a state that the contact portion is contacted against the testing annular portion; and release operation to release coupling of the testing tube from the testing member by loosening a fastening state after the fastening operation,
if a maximum axial force generated in a first performance of the fastening test is termed an initial axial force F1 (kN) and a maximum axial force generated in an n-th performance of the fastening test is termed an n-th axial force Fn (kN), and if a value obtained by −(Fn−F1)/(n−1) is defined as being an axial force decrease ratio α (kN/turn),
a range of the mass per unit area w is set so as to satisfy relations: F1<14.0 and 0<α<1.75.