The crimping type hydraulic hose fitting consists of a stem, a nut, and a ferrule.
The main factors affecting the fitting performance are the length of the stem, the structure, wall thickness, and the material. From the perspective of sealing and pull-out prevention, the longer stem is required. But overlong stem will cause materials waste and increase manufacturing costs. The general design requires stem length is slightly longer than the ferrule.
There are different types of stem structure. The main ones are R grooves and zigzag grooves. Both can increase the friction and provide a rubber containing groove. At present, steel wire braided hoses use R grooves, and high-pressure spiral hose use zigzag grooves.
Material: The fitting material is generally made of 1020 #, 1035 #, 1045 # carbon steel. To prevent the inner hole deformation of the fitting during crimping which will increase the liquid resistance. The thickness of the stem should be 1.5 ～ 3 .5mm. The space between stem O.D. and hose I.D. should not be too much. Otherwise, it will damage the inner rubber and make the installation more difficult. Too small stem I.D. will increase fluid resistance and cause pressure drop loss. Because the stem O.D. is limited while hose size varies much. Optimizing the crimping data is necessary to achieve the hose assembly performance.
Thanks for your blog, nice to read. Do not stop.