Lubricating oil composition

Abstract

The present invention provides a lubricating oil composition that maintains properties necessary to lubricating a transmission and other devices and has more excellent insulation properties and anti-wear properties and more improved anti-seizure properties than the prior art and comprises (A) a lubricating oil base oil; (B) at least one type of phosphorus compound selected from the group consisting of phosphorus compounds having at least one hydroxyl group and/or at least one thiol group; and (C) an ashless dispersant having a functional group containing as a dispersion group in an amount of less than 0.001 percent by mass on the basis of nitrogen on the total composition mass basis or no such an ashless dispersant at all, the composition having a 80° C. volume resistivity of 5×10 8 Ω·m or greater.

1 . A lubricating oil composition comprising:
 (A) a lubricating oil base oil;   (B) at least one type of phosphorus compound selected from the group consisting of phosphorus compounds having at least one hydroxyl group and/or at least one thiol group; and   (C) an ashless dispersant having a functional group containing as a dispersion group in an amount of less than 0.001 percent by mass on the basis of nitrogen on the total composition mass basis or no such an ashless dispersant at all, the composition having a 80° C. volume resistivity of 5×10 8 Ω□m or greater.   
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein (B) the phosphorus compound having a hydrocarbon group having 16 or fewer carbon atoms. 
     
     
         3 . The lubricating oil composition according to  claim 1 , wherein the composition is used for the transmission, both transmission and electric motor, or the device in which a lubricating system is shared by the transmission and electric motor, mounted in a fuel cell electric vehicle, an electric vehicle or a hybrid vehicle. 
     
     
         4 . The lubricating oil composition according to  claim 2 , wherein the composition is used for the transmission, both transmission and electric motor, or the device in which a lubricating system is shared by the transmission and electric motor, mounted in a fuel cell electric vehicle, an electric vehicle or a hybrid vehicle.