Continuously variable transmission fluid

Abstract

A composition suitable for lubricating a continuously variable transmission comprising a lubricating oil containing an ashless dispersant, a spiro bicyclodiphosphite, a calcium detergent lubricating oil additive, and, optionally, a succinimide friction modifier and an organic mono- or di-hydrogen phosphite.

1 . A lubricating composition for lubricating a continuously variable transmission, the lubricating composition comprising a mixture of: 
 (1) a major amount of a lubricating oil; and    (2) an effective amount of a performance enhancing additive combination comprising: 
 (a) an ashless dispersant;  
 (b) a spiro bicyclodiphosphite having the following structure:  
                     
   wherein R and R 1  can vary independently and are C 1 -C 20  aliphatic hydrocarbyl groups; 
 (c) a calcium detergent lubricating oil additive;  
 (d) optionally, a succinimide friction modifier having the structure:  
                     
 wherein R 2  and R 3  can vary independently and are C 6 -C 30  alkyl, and z=1 to 10, and  
   (e) optionally an organic phosphite having the following structure:                          where R 4  is C 1 -C 20  hydrocarbyl and R 5  is C 1 -C 20  hydrocarbyl or hydrogen, with the proviso that the composition does not contain molybdenum.    
   
   
       2 . The composition of  claim 1  wherein the calcium detergent is an overbased sulfonate, phenate or sulfurized phenate.  
   
   
       3 . The composition of  claim 1  wherein the dispersant is a polyisobutenyl succinimide.  
   
   
       4 . The composition of  claim 1  wherein the R and R 1  groups of the spiro bicyclodiphosphite are isodecyl.  
   
   
       5 . The composition of  claim 1  wherein the (e) ingredient is present.  
   
   
       6 . The composition of  claim 5  wherein the R 4  and R 5  groups are linear alkyl having 4 to 18 carbon atoms containing one sulfur atom.  
   
   
       7 . The composition of  claim 1  wherein there is present 0.5 to 7.0 mass % of the dispersant.  
   
   
       8 . The composition of  claim 1  wherein there is present 0.2 to 8.0 mass % of the spiro bicyclodiphosphite.  
   
   
       9 . The composition of  claim 1  wherein there is present 0.05 to 3.0 mass % of the calcium detergent.  
   
   
       10 . The composition of  claim 1  further comprising an additive selected from the group consisting of viscosity modifiers, antioxidants, seal swellants, corrosion inhibitors, antifoaming agents, antiwear agents, supplemental metal detergents and pour point depressants.  
   
   
       11 . A CVT apparatus containing the fluid of claims  1 - 10 .  
   
   
       12 . A method of lubricating a CVT apparatus comprising operating said apparatus using the fluid of claims  1 - 10 .