KR100488860B1 - Compostion for variable continuously transmission fluid - Google Patents

Abstract

The present invention relates to a continuously variable transmission oil composition, and more specifically, 50 to 95% by weight of base oil, 0.01 to 2% by weight of abrasion resistant agent, 0.05 to 5% by weight of metal-based clean dispersant, 0.01 to 3% by weight of friction modifier and viscosity index improver. It is related with the continuously variable transmission oil composition which is excellent in a shift performance and durability by consisting of 0.05-20 weight% of other additives included.

Description

Continuously variable oil composition

The present invention relates to a continuously variable transmission oil composition, and more specifically, 50 to 95% by weight of base oil, 0.01 to 2% by weight of abrasion resistant agent, 0.05 to 5% by weight of metal-based clean dispersant, 0.01 to 3% by weight of friction modifier and viscosity index improver. It is related with the continuously variable transmission oil composition which is excellent in a shift performance and durability by consisting of 0.05-20 weight% of other additives included.

In order to improve the performance, durability and convenience of the vehicle, the requirements of the automobile gear oil are becoming strict, and in particular, in order to improve the driver's convenience, vehicles with automatic transmissions are increasing rather than manual transmissions. However, the automatic transmission has a problem in that the fuel economy is lowered compared to the manual transmission due to its structure, and a continuously variable transmission (Variable Continuously Transmission) has been developed and created for the purpose of improving fuel efficiency and convenience.

Currently, continuously variable transmissions are not installed on high-torque vehicles, and are usually mounted on vehicles under 2,000 cc. In terms of structure, the continuously variable transmission has the same torque converter and clutch as the automatic transmission, but the power transmission and gear structure are designed differently. Therefore, the continuously variable transmission oil has similar characteristics to the STEEL-PAPER clutch friction characteristics, which are required characteristics of the automatic transmission oil. Therefore, the continuously variable transmission oil can be used in common with the existing automatic transmission oil, but it can be used in high torque vehicles or to improve power transmission capability. Some makers use proprietary oils.

As the transmission power of the continuously variable transmission and the improvement of ride comfort are required, the required characteristics of the continuously variable transmission oil are also being raised. In general, continuously variable transmission oil in which power transmission and shifting are performed by a belt-pulley requires additional friction characteristics between the belt and the pulley in addition to the required characteristics of the automatic transmission oil.

In general, the belt-pulley consists of STEEL, and the shifting principle is shifted automatically by changing the width of the second pulley steplessly in response to the change of the width of the primary pulley. Therefore, in the continuously variable base oil, when the metal belt moves in the vertical direction of the pulley shaft when the width of the pulley is changed, the shear of oil is most generated. At this time, when the friction coefficient is low, the belt slips and the wear of the metal belt occurs. In order to prevent excessive wear of the belt, the coefficient of friction should be maintained above 0.1. Scratch noise is generated when the μ-V characteristic is bad when the belt-pull type CVT vehicle starts or stops. If the friction coefficient (μ) increases as the belt moves vertically (V) as the belt moves in the vertical direction of the pulley, the belt transmits power normally, but when the speed increases, the coefficient of friction increases. When low, the belt and pulleys will slip and generate noise. In other words, the normal friction coefficient (μs) / dynamic friction coefficient (μd) ratio must be maintained at 0.9 ~ 1.0 in order to achieve normal power transfer. Thus, continuously variable transmission oils require high coefficients of friction and good μ-V characteristics in metal-to-metal contact between belts and pulleys.

Generally, the exclusive oil used in continuously variable transmission uses zinc dithiophosphate (Zn-DTP) and metal cleansing dispersant. The ASH TYPE additive made of metal salt has higher metal-metal friction coefficient than ASHLESS TYPE but improves μ-V characteristics. It is difficult to extend the exchange cycle because there is a limit to the oxidation stability is not good, there is a problem that does not extend the clutch durability life applied STEEL-PAPER.

Accordingly, the present inventors have studied for producing a continuously variable transmission oil having excellent shifting performance and durability than a continuously variable transmission oil using zinc dithiophosphate (Zn-DTP) and a metal cleansing dispersant, and have excellent heat resistance and friction between metals and metals. The present invention has been completed by developing a continuously variable transmission oil having excellent transmission performance and durability by appropriately combining a friction modifier having high coefficient, excellent µ-V characteristics, an anti-wear additive having excellent heat and wear resistance, and a metal cleansing dispersant.

Accordingly, an object of the present invention is to provide a continuously variable transmission oil composition having excellent shift performance and durability, which is composed of other additives including a base oil, an anti-wear agent, a metal-based dispersant, a friction modifier, and a viscosity index improver.

The present invention provides a continuously variable base oil composition containing a base oil, a metal cleansing dispersant and an additive, comprising: (1) 86 to 95 wt% of a base oil; 0.05 to 5% by weight of an organic molybdenum antiwear agent; (3) 0.05 to 5% by weight of a metal salt cleansing dispersant of magnesium sulfonate having a total salt value of 200 or more; And (4) 0.01 to 3% by weight of a friction modifier of glycerin poly-oleic ether.

The present invention will be described in detail as follows.

In the above composition, it is preferable to use 86 to 95% by weight of a fixed mineral oil or a synthetic oil having a kinematic viscosity of 3 to 10 cSt and a viscosity index of 100 or more at 100 ° C.

The antiwear agent is a zinc dithiophosphate (ZnDTP) and an organic molybdenum antiwear agent, and MoDTC (Molybdenum Ditiocarbamate) and MoDTP (Molybdenum Ditiophosphate) alone or in combination. It is preferable to mix the MoDTC: MoDTP in a 2: 1 to 3: 1 ratio (weight ratio) because it serves to keep the static friction coefficient between metals constant. When the organic molybdenum is less than 0.01% by weight, the gear durability is lowered. When the organic molybdenum is more than 2% by weight, the metal-to-metal static friction coefficient of the belt-pull is lowered. The total content of the anti-wear agent is preferably 0.05 to 5% by weight. If the content is less than 0.05% by weight, the gears and bearing parts may be worn or broken. If the amount is more than 5% by weight, the shift of the belt-pulley may be reduced due to a decrease in friction characteristics of the belt-pull. There is a problem that goes bad.

In addition, the metal-based clean dispersant is preferably used alone or in combination with magnesium sulfonate having a total base value of 200 or more, calcium sulfonate, and magnesium pinate. The metal-based clean dispersant keeps the metal-metal dynamic friction coefficient of the belt-pulley high. If it is less than 0.05% by weight, the metal-metal dynamic friction coefficient of the belt-pulley is lowered. There is a problem that the durability of the gear and bearing is lowered.

As a friction modifier, it is preferable to use glycerin poly-oleic ether, which has the effect of increasing the coefficient of dynamic friction between metals and metals and decreasing the coefficient of static friction. Preferably, the friction modifier is used in an amount of 0.01 to 3% by weight. If the content is less than 0.01% by weight, the desired effect is not achieved.

As other additives, a viscosity index improver, a fluidity improver, an antifoaming agent, an anticorrosive agent, and the like are used, and the content thereof is preferably 0.05 to 20% by weight.

Such continuously variable transmission oil composition has good shifting performance and can extend the service life. In addition, since the dynamic coefficient of static and static friction between the belt and the pulley is improved, there is an excellent effect on the performance and noise prevention of the continuously variable transmission mounted on a high torque vehicle.

Hereinafter, the present invention will be described in detail based on the following examples, but the present invention is not limited by the following examples.

Examples 1-3 and Comparative Examples 1-2

Next, continuously variable transmission oil was prepared in the composition shown in Table 1. At this time, the unit of each component represents the weight%.

Test Example

The compositions of Examples 1 to 3 and Comparative Examples 1 and 2 were subjected to the BLOCK-ON-RING test at 110 ° C according to ASTM D 2714 test method and the results are shown in Table 2 below. The dynamic friction coefficient was measured at 1.0 m / s, and the static friction coefficient was measured at 0.05 m / s.

As shown in Table 2, the composition of Examples 2 and 3 has a high coefficient of friction, maintains a proper coefficient of static / dynamic friction, and does not show a problem that the TIMKEN OK load is lowered even when a friction modifier is used. Was able to achieve

Therefore, the composition consisting of 50 to 95% by weight of base oil, 0.05 to 5% by weight of antiwear agent, 0.05 to 5% by weight of metal salt dispersant, and 0.01 to 3% by weight of glycerin poly-oleic ether as friction modifier -By increasing the coefficient of friction of the belt, it can be used for continuously variable transmission of high torque vehicles, and it has good shifting performance and extends the durability life. In addition, it is effective in preventing noise.

Claims (4)

In the continuously variable transmission oil composition comprising a base oil, a metal clean dispersion and an additive, (1) 86 to 95% by weight of base oil; (2) 0.05 to 5% by weight of an organic molybdenum antiwear agent alone or in combination of MoDTC (Molybdenum Ditiocarbamate) and MoDTP (Molybdenum Ditiophosphate); (3) 0.05 to 5% by weight of a metal salt clean dispersant of magnesium sulfonate having a total salt value of 200 or more; And (4) 0.01-3% by weight of friction modifier of glycerin poly-oleic ether Continuously variable transmission oil composition comprising a. The continuously variable transmission oil composition according to claim 1, wherein the base oil has a 100 ° C kinematic viscosity of 3 to 10 cSt and is mineral or synthetic oil. The continuously variable transmission oil composition according to claim 1, wherein the organomolybdenum antiwear agent is further mixed with an antiwear additive of zinc dithiophosphate (ZnDTP). The continuously variable transmission oil composition according to claim 1, wherein the metal salt clean dispersant is further mixed with calcium sulfonate.