| Pilot operated water hydraulic control valve is a key control element of water hydraulic system. Due to the special physical and chemical properties of water medium, lubrication and sealing problems of the key friction in the valve have become key issues affecting performance of the valve.The natural pore space structure of natural bone is considered beneficial to store lubricating fluid, which inspires us that natural bone can be used to improve lubrication and sealing problems.Natural bone, 316 L stainless steel, nitrided 316 Lstainless steel, Al2O3 ceramic and ZrO2 ceramic, carbon fiber reinforced polyetheretherketone(CFRPEEK) were matched with each other and were tested on pin-on-ring tribometer under water lubrication for the research of friction and wear properties at low speed. It is found that the friction coefficients of natural bone/metal and natural bone/ceramic are very stable and they are all about 0.16~0.29, but the weight loss of natural bone/ceramic is significantly more than that of natural bone/metal. The main wear mechanism of natural bone/metal are micro-cutting by particles falling from the surface of bone. The wear mechanism of natural bone/ceramic are fatigue wear, and main wear forms are the increased pores and microcracks on the surface of bone.Erosion experiments and salt spray test were carried out for the study of erosion and corrosion resistance. It is shown that natural bone has a poor erosion resistance but that can be improved in case of having a back pressure through analog valve port erosion experiments. Standard erosion experiments were carried out on the MSH corrosion and wear tester, which also verified the poor erosion resistance of natural bone. It is also found that natural bone has the excellent resistance to seawater corrosion.Natural bone was processed into the valve sleeve to provide guidance and support for the valve core. The structure was applied to the design of pilot operated water hydraulic relief valve. Good experimental results showed excellent performance of lubrication and sealing between valve core and valve sleeve, besides it also proved the rationality of the structure. It is shown that having a certain friction between main valve core and valve sleeve is beneficial to the stability of the main valve core through simulation. |
