Methods for lubricating a transmission

Abstract

The present invention discloses a method for lubricating a transmission having at least one electromechanical component and at least one mechanical component in a single housing. The method includes supplying a lubricant composition made up of (a) a base oil; (b) an oil soluble, phosphorus-containing compound; and (c) a corrosion inhibitor to the transmission.

1 . A method for lubricating a transmission having at least one electromechanical component and at least one mechanical component in a single housing comprising supplying to the transmission a lubricant composition comprising: (a) a base oil; (b) an oil soluble, phosphorus-containing material; and (c) a corrosion inhibitor. 
     
     
         2 . The method according to  claim 1  wherein the base oil has a dielectric strength greater than or equal to 30 KV as measured in accordance with ASTM D877. 
     
     
         3 . The method according to  claim 1  wherein the base oil is selected from the group consisting of natural lubricating oils, synthetic lubricating oils and mixtures thereof. 
     
     
         4 . The method according to  claim 3  wherein the base oil is a natural lubricating oil comprising a mineral oil. 
     
     
         5 . The method according to  claim 3  wherein the base oil is comprised of at least 50 mass percent of synthetic lubricating oil. 
     
     
         6 . The method according to  claim 1  wherein the oil soluble, phosphorus-containing material comprises an ester of an acid of phosphorus in a valence state of either III or V. 
     
     
         7 . The method according to  claim 6  wherein the oil soluble, phosphorus-containing material is a neutral compound. 
     
     
         8 . The method according to  claim 1  wherein the oil, soluble phosphorus-containing material is a mixed thio-alkyl phospiate. 
     
     
         9 . The method according to  claim 1  wherein the amount of phosphorus-containing material in the lubricant composition is less than or equal to 200 ppm. 
     
     
         10 . The method according to  claim 1  wherein the corrosion inhibitor is selected from the croup consisting of triazoles and materials based on thiadiazoles as well as combinations and mixtures thereof. 
     
     
         11 . The method according to  claim 10  wherein the corrosion inhibitor comprises an aromatic triazole and a mercaptothiadiazole. 
     
     
         12 . The method according to  claim 1  wherein the corrosion inhibitor is present in an amount less than or equal to 0.5 weight percent of the composition. 
     
     
         13 . The method according to  claim 1  wherein the lubricant composition further comprises a second ashless dispersant 
     
     
         14 . The method according to  claim 13  wherein the second ashless dispersant is selected from the group consisting of (a) succinimides produced from polyalkenyl succinnic anhydrides and polyamines and (b) Mannich base type dispersants made from alylated phenols formaldehyde and polyamines. 
     
     
         15 . The method according to  claim 13  wherein the second ashless dispersant is present in the lubricant composition in an amount less than or equal to 5 mass percent. 
     
     
         16 . The method according to  claim 1  wherein the mechanical components comprise at least one of the following: (1) reduction gearing; (2) differentials; (3) power splitting devices; and (4) torque limiting devices. 
     
     
         17 . The method according to  claim 1  wherein the electromechanical component comprises at least one of the following: (1) electric drive motors; (2) generators; (3) motor-generator combination units; and (4) alternators. 
     
     
         18 . The method according to  claim 1 , wherein the transmission is included in a hybrid vehicle. 
     
     
         19 . A lubricant composition comprising: (a) a base oil; (b) an oil soluble, phosphorus-containing material; and (c) a corrosion inhibitor, wherein the lubricant composition is used in a transmission having at least one electromechanical component and at least one mechanical component in a single housing. 
     
     
         20 . A transmission containing the lubricant composition recited in  claim 19 . 
     
     
         21 . An additive package for a lubricant composition comprising: (a) an ashless dispersant; (b) an oil soluble, phosphorus-containing material; and (c) a corrosion inhibitor.