emanuel
Well-Known OPE Member
There seems to be a substantial negative impact on polyamide’s physical properties (after a relatively short soak in polyalphaolefin -PAO- oil as compared to a polyol ester -POE- oil.)
Research article in question
Figure 5 and 6 specifically, the tensile strength of the polyamide seems to suffer when in contact with a PAO oil, especially at 120 C, which is a temperature that the clutch side bearing could attain.
Quote “It is evident from these curves that the specimens in contact with PAO experienced a greater reduction in elasticity, with the specimens at 120 °C even fracturing before undergoing plastic deformation.”
This might be significant considering the main reason why these are used over a steel cage is its resistance to cracking and impact resistance, and no issues with shearing/fatigue as its the case with a metal cage. (The purpose of the study is for unserviceable bearings for electric cars, where lifespan really matters).
What do you guys think, seems like a good reason to avoid pao oils in these modern saws. Could the people that had these bearings fail in their saws be due to using an incompatible oil? Either way, as its stated in the conclusion of the research, this is just a test with the base oils. The additives might influence these interactions in all kinds of different ways, so who really knows..
Link to an SKF article where the advantages and disadvantages of these plastic cages are explained better for anyone interested.
Research article in question
Figure 5 and 6 specifically, the tensile strength of the polyamide seems to suffer when in contact with a PAO oil, especially at 120 C, which is a temperature that the clutch side bearing could attain.
Quote “It is evident from these curves that the specimens in contact with PAO experienced a greater reduction in elasticity, with the specimens at 120 °C even fracturing before undergoing plastic deformation.”
This might be significant considering the main reason why these are used over a steel cage is its resistance to cracking and impact resistance, and no issues with shearing/fatigue as its the case with a metal cage. (The purpose of the study is for unserviceable bearings for electric cars, where lifespan really matters).
What do you guys think, seems like a good reason to avoid pao oils in these modern saws. Could the people that had these bearings fail in their saws be due to using an incompatible oil? Either way, as its stated in the conclusion of the research, this is just a test with the base oils. The additives might influence these interactions in all kinds of different ways, so who really knows..
Link to an SKF article where the advantages and disadvantages of these plastic cages are explained better for anyone interested.
