JP3261978B2 - Worm gear oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a worm gear oil composition, and more particularly to a worm gear oil composition suitable for a copper-based worm gear containing aluminum, silicon or manganese.

[0002]

2. Description of the Related Art In recent years, worm gears have tended to be smaller and more efficient, and the load on lubricating oil used has also increased significantly. As such a lubricating oil for a worm gear, conventionally, for example, a lubricating oil composed of a mineral oil, a fat (ester) or a fatty acid and partially containing a phosphorus compound has been used. On the other hand, phosphor bronze has conventionally been used as a worm gear worm material. However, in recent years, aluminum bronze or high-grade bronze has been used as the material in view of the tendency of worm gears to be miniaturized and their hardness, abrasion resistance, seizure and the like. Conversion to copper-based alloys containing aluminum, silicon, manganese, etc., such as brass, has been performed. However, in the case of a conventional lubricating oil composed of the above-described mineral oil or the like, if the lubricating oil is applied to a worm gear composed of a copper-based alloy containing aluminum, silicon, manganese, or the like, gear characteristics such as load resistance and transmission efficiency are not sufficient. There was a problem. There has also been a demand for a worm gear oil that does not adversely affect organic materials such as sight glass, paint, and seals that are commonly used in the apparatus. That is, a lubricating oil suitable for a worm gear made of the novel material has not been obtained yet.

[0003]

The present invention has been made under such circumstances. That is, the present invention particularly provides a worm gear oil composition suitable for a copper-based worm gear containing at least one selected from aluminum, silicon and manganese, and has particularly good gear characteristics such as load resistance and transmission efficiency. It is an object of the present invention to provide a worm gear oil composition that does not adversely affect organic materials such as paints, seals, and sight glass.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, used a synthetic oil obtained by combining a specific compound as a base oil and added a specific molybdenum compound It has been found that the worm gear oil containing the compound exhibits good gear characteristics even with the above-mentioned copper-based alloy worm gear, and does not adversely affect organic materials such as paints, seals, and sight glass. The present invention has been completed based on such findings. That is, the present invention comprises blending a molybdenum compound with a base oil comprising an alkyl group-substituted aromatic compound such as alkylbenzene or alkylnaphthalene and a poly-α-olefin, and in particular, at least one selected from aluminum, silicon and manganese. A worm gear oil composition characterized by being used for a worm gear having a copper-based alloy worm containing:

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the present invention, as the base oil of the worm gear oil composition, one comprising an alkyl group-substituted aromatic compound such as alkylbenzene or alkylnaphthalene and a poly-α-olefin is used. The various properties are not particularly limited, but from the viewpoint of the oil film thickness during operation at a high temperature, that is, the oil film strength, the viscosity index is 130.
More preferably, it is 140 or more.
Therefore, in the present invention, it is preferable to further add a viscosity index improver to the base oil. Examples of the viscosity index improver that can be used include polymethacrylate, polyisobutylene, and ethylene {α} olefin copolymer, and the number-average molecular weight is 1,000 to 800,000, and more preferably 1.5 to 1.5.
Those having a size of from 00 to 300,000, particularly from 2,000 to 100,000 can be preferably used. In the present invention, among these, an ethylene {α} olefin copolymer is particularly preferred from the viewpoint of shear stability and the like. The viscosity index improver is preferably contained in the worm gear oil composition of the present invention in an amount of 5 to 20% by weight. If the content is less than 5% by weight, the effect of improving the viscosity index is small, and if it exceeds 20% by weight, the viscosity may be too high. In the present invention, these viscosity index improvers can be used singly or in combination of two or more.

Various poly-α-olefins can be used as the base oil. For the purpose of improving the viscosity index, oligomers of ethylene and α-olefins having 6 to 14 carbon atoms are used. A polymer can be preferably used, and in particular, a decene oligomer, an ethylene-propylene copolymer, or a mixture thereof can be preferably used. Further, the viscosity at 40 ° C. is 30 to 1
It is preferable to use one in the range of 000 cSt. When the viscosity is less than 30 cSt, the oil film thickness becomes too small, and when it exceeds 10,000 cSt, the viscosity of the composition becomes too high, and the viscosity may decrease due to mechanical or thermal shearing. For these reasons,
More preferably, the above range is 50 to 5,000 cSt.

In the present invention, alkylbenzene is used as one of the alkyl-substituted aromatic compounds constituting the base oil together with the poly-α-olefin. Such an alkylbenzene is used for the purpose of oxidative stability and preventing the generation of sludge. In the present invention, an alkylbenzene substituted with a branched alkyl group can be particularly preferably used. Examples of such a branched alkyl group include an olefin group obtained by polymerizing ethylene, propylene, and butylene. As the alkyl group of the alkylbenzene, those having 8 to 30 carbon atoms, preferably 10 to 20 carbon atoms can be used. When this value is smaller than the above range, the viscosity becomes low and the oil film strength is insufficient, and when it is larger than the above range, the solubility of sludge generated by oxidative deterioration may be insufficient. As the above-mentioned alkylbenzene, those having a viscosity index of 100 or less are preferably used from the viewpoint of the solubility of sludge and the like. Further, those having a viscosity at 40 ° C. of 20 to 200 cSt can also be preferably used. The above viscosity is 20 cSt
If it is less than 200 ° C., the oil film strength during high-temperature operation may be insufficient or the evaporation loss may be large. If it exceeds 200 cSt, the solubility of the sludge generated by oxidative deterioration may decrease. For these reasons, the above range is from 20 to 10
More preferably, it is 0 cSt.

In the present invention, an alkylnaphthalene can be used in place of the above-mentioned alkylbenzene. The alkyl naphthalene that can be used in the present invention includes a reaction product of an α-olefin and naphthalene. Here, the α-olefin has 10 to 3 carbon atoms.
0, specifically tetradecene, hexadecene,
Octadecene, eicosene, etc. can be used. The viscosity and viscosity index of the above-mentioned alkylnaphthalene at 40 ° C. are preferably the same as those of the above-mentioned alkylbenzene. In the present invention, the mixing ratio of the poly-α-olefin to the alkyl group-substituted aromatic compound is 50/50 to 95 by weight.
/ 5 is preferred. If the blending amount of the poly-α-olefin is less than the above range, the viscosity index of the composition is lowered, so that the formation of an oil film at a high temperature is inferior. Therefore, the mixing ratio is more preferably 60/40 to 95/5.

In the worm gear oil composition of the present invention, a molybdenum compound is blended with the above base oil. As the molybdenum compound, an organic molybdenum compound is preferably used. In particular, an improvement in gear transmission efficiency, suppression of an increase in oil temperature,
Molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (M
oDTC) and the like are preferably used. Such a molybdenum compound is contained in the worm gear oil composition of the present invention in an amount of 0.1 to 0.1.
10% by weight is contained. The compounding amount of the molybdenum compound is 0.
If the amount is less than 1% by weight, the transmission efficiency of the gear is low, the oil temperature increases, and the gear tooth surface is damaged. On the other hand, if it exceeds 10% by weight, oxidative stability and thermal stability decrease. Therefore, the amount is more preferably 0.1 to 5% by weight.

In the worm gear oil composition of the present invention, in addition to the above molybdenum compound, if necessary, an antioxidant, a copper deactivator, a rust inhibitor, a dispersant, etc. are added as long as the object of the present invention is not impaired. Agents can be included. As the antioxidant that can be used in the present invention, for example, an amine antioxidant, a phenolic antioxidant, and the like can be used. Examples of the copper deactivator include benzotriazole-based compounds and thiadiazole-based compounds, and examples of the rust preventive include alkaline earth metal salts of sulfonates and alkenyl succinates. For example, alkenyl succinimides, acid amides and the like can be used. The above additives can be contained in the composition in an amount of 5% by weight or less, respectively, and a total of 10% by weight or less. The worm gear oil composition of the present invention has a viscosity index of 130 or more, preferably 140 or more, and a viscosity at 40 ° C of 100 to 1,000 c.
It is preferably St. If the viscosity is less than 100 cSt, the oil film strength becomes insufficient, the oil temperature rises, and the gear tooth surface damage increases. In addition, 1,000 cSt
When the ratio exceeds, the stirring resistance increases and the transmission efficiency decreases. Therefore, the viscosity range is more preferably from 150 to 700 cSt.

The worm gear oil composition of the present invention is suitably used for a worm gear having a worm made of a copper-based alloy containing at least one selected from aluminum, silicon and manganese. Such copper-based alloys include those containing 1 to 15% by weight of aluminum, those containing 0.1 to 3% by weight of silicon, those containing 0.5 to 5% by weight of manganese, and those containing two or more of these. Those containing at least the species and the respective amounts are preferably used. When two or more of these are contained, the total content is preferably 2 to 20% by weight. If the content is out of the above range, the hardness of the worm may be insufficient, which is not preferable. The copper-based alloy used for the worm may optionally further contain a metal such as zinc, iron, and nickel. In the present invention, the above aluminum,
Preferred examples of the copper-based alloy containing at least one selected from silicon and manganese include high-strength brass and aluminum bronze. The worm gear oil composition of the present invention can be applied to, for example, worm gears used for various industrial machines, escalators, moving walkways, unloading cranes, sail drive devices, and the like.

[0012]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The performance of the worm gear oil is
The evaluation was performed by the following method. In this case, a worm gear having a worm made of the following material was used. Material of worm Aluminum bronze (FA-381 manufactured by Hitachi, Ltd.) Components: Fe (3.2%), Ni (3.5%), Cu (remainder), Al (8.3%), Si (1%) .2%) Hardness; H _B = 156

Performance Evaluation Method Worm Gear Oil Test Method for Actual Machine The following performances of the worm gear oil of the present invention were evaluated using an actual machine as follows. 3.7kw motor 180
It rotates at 0 rpm, drives a worm gear (reduction ratio 60: 1) made of the above material, and sets the output rotation speed to 30 rpm,
In addition, a hydraulic pump was driven via a gearbox. At this time, the input torque and the output torque of the worm gear were measured by a torque meter. Oil Temperature Rise (° C.) The difference between the oil temperature when the apparatus was operated at the rated load (100% load) for 50 hours and the room temperature at that time was defined as the raised oil temperature. Energy transfer efficiency (%) Energy transfer efficiency was calculated by the following equation. Energy transmission efficiency (%) = [(output torque (kgf
m) × 30) / (input torque (kgf · m) × 180
0)] × 100 Gear Wear (Backlash) (mm) The backlash change (mm) before and after 50 hours of operation was measured.

[0014]LFW-1 test (block-on-ring test
Experiment) Use a block ring made of
0 lbs. , Rotation speed 500rpm, oil temperature 80 ℃, time
The block was operated under the conditions of 30 minutes, and the wear width (m
m) was measured.Condition A Block material: Aluminum bronze (Hitachi, Ltd.)
FA-381) Components: Fe (3.2%), Ni (3.5%), Cu (remainder)
Part), Al (8.3%), Si (1.2%) Hardness; H_B= 156 Ring material: SAE4620 steel (Ni-Mo steel) Composition: C (0.20%), Si (0.28%), Mn (0.2%)
55%), Mo (0.25%), Ni (1.85%), Fe
(Remainder) Hardness; R_C= 58-63Condition B Block material: Manganese silicide high-strength brass (Chuetsu alloy casting
CGM-3 manufactured by Koko Co., Ltd.) Components: Al (1.3%), Mn (2.2%), Si (1.0%)
%), Pb (0.8%), Cu (remainder), Zn (34.9)
%), Sn (0.05%), Ni (0.0
7%) Hardness; H_B= 121 Ring material: SAE4620 steel (Ni-Mo steel) Composition: C (0.20%), Si (0.28%), Mn (0.2%)
55%), Mo (0.25%), Ni (1.85%), Fe
(Remainder) Hardness; R_C= 58-63

Examples 1 to 5 and Comparative Examples 1 to 3 Using the base oils shown in Table 1, worm gear oils having the compositions and compounding ratios (% by weight) shown in Table 2 were prepared. The performance was evaluated. The results are shown in Table 2.
The performances of the base oil and the gear oil other than those described above were evaluated by methods according to JIS.

[0016]

[Table 1]

Base oil (1): poly-α-olefin (decene oligomer) Base oil (2): Alkyl benzene (branched heavy alkyl benzene having 1 to 3 alkyl groups having 12 carbon atoms) Base oil (3): Alkyl naphthalene (alkyl naphthalene having one or two alkyl groups having 16 or 18 carbon atoms)

[0018]

[Table 2]

[0019]

[Table 3]

Viscosity index improver: ethylene-propylene copolymer (number average molecular weight 3,600) Additive (1): molybdenum dithiophosphate (Mo-DT)
P) (Mo = 9.0%, S = 10.0%, P = 3.3%) Additive (2): Molybdenum dithiocarbamate (Mo
-DTC) (Mo = 4.7%, S = 6.0%, N = 0.7%) Additive (3): Sulfur-phosphorus extreme pressure agent (IGA4689 manufactured by Ethyl Japan Co., (S = 14. 0%, P = 0.5%,
N = 0.5%) Additive (4): Phosphorus extreme pressure agent (phosphate amine salt, P = 2.5%, N = 0.3%) Additive (5): Phosphorus additive ( Tricresyl phosphate, P = 8.3%) Additive (6): Antioxidant (dialkyldiphenylamine) Additive (7): Rust inhibitor (Ba-sulfonate, Ba =
6.6%) Additive (8): Copper deactivator (1,2,3-benzotriazole)

[0021]

As described above in detail, the worm gear oil composition of the present invention is suitable for a copper-based worm gear containing aluminum, silicon, and manganese, and is particularly suitable for gears having load resistance and transmission efficiency. Good properties, paint,
It does not adversely affect organic materials such as seals and sight glasses.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 139: 00) C10M 139: 00) C10N 10:12 C10N 10:12 30:00 30:00 Z 30:06 30:06 40 : 04 40:04

Claims (4)

(57) [Claims] 1. An alkyl group-substituted aromatic compound and poly-α
- Ri Do from an olefin, poly -α- olefin and Al
The compounding ratio of the aromatic compound substituted with a kill group is 50/5 by weight.
0-95 / 5 der Ru base oil a worm gear oil composition obtained by blending a molybdenum compound, worm gear is A
At least selected from luminium, silicon and manganese
A worm gear oil composition having a worm made of a copper-based alloy containing at least one kind . 2. The worm gear oil composition according to claim 1, wherein the poly-α-olefin is a decene oligomer, an ethylene-propylene copolymer or a mixture thereof. 3. The worm gear oil composition according to claim 1, wherein the alkyl group-substituted aromatic compound is benzene or naphthalene substituted with an alkyl group. 4. The worm gear oil composition according to claim 1, further comprising at least one selected from an antioxidant, a copper deactivator, a rust inhibitor and a dispersant.