JPH0228634B2 - KOGYOYOGYAABURASOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in industrial gear oil compositions, and more particularly to energy-saving industrial gear oil compositions that can significantly reduce the coefficient of friction and wear of gears. In recent years, energy saving measures have been required in many fields in the industrial world, and industrial machinery, such as rolling equipment in steel factories, cranes as construction machinery, and high-load machinery found in the main engines of marine turbines, etc. Energy conservation has also become an important issue. In other words, there is a demand for a gear oil that is effective in reducing the frictional energy of operating gears in these high-load mechanical devices and preventing damage to the gears. Conventionally, industrial gear oils for the above-mentioned mechanical devices have been made by adding sulfur-based additives (referred to as S-P-based) or lead soap-sulfur-based additives (Pb-S) to the base oil. In the past, additives containing a substance mainly composed of However, the above S-P system or Pb-S
If any type of gear oil containing additives is used for a long period of time, the gear tooth surface will become
The drawback is that it gradually becomes rough, causing surface damage such as pitting, and at the same time, frictional energy loss increases. Incidentally, conventional industrial gear oils have focused on extreme pressure properties and seizure prevention, and have not paid much attention to pitting resistance and friction resistance. In other words, the anti-seizure effect of conventional industrial gear oils is exerted by the so-called extreme pressure coating that is produced by the reaction between the additives added to it and the base metal of the gear. Since the coating is not uniformly formed on the gear surface, roughness or pitting of the gear surface is unavoidable, resulting in wear and friction loss as described above. The present inventor has completed the present invention as a result of studies aimed at eliminating the drawbacks found in industrial gear oils as described above. That is, an object of the present invention is to provide an industrial gear oil that can contribute to energy saving by suppressing damage to gear base metal, smoothing the damaged gear surface, high load carrying capacity, and reducing friction coefficient. do. The present invention will be explained in detail below. The base oil used in the present invention is generally mineral oil or a mineral oil-based base oil, and
Any material having an appropriate viscosity may be used. Such mineral oils are obtained by processing crude oil through ordinary pressure distillation, vacuum distillation, etc., which are lubricating oil refining methods used in the oil refining industry, to obtain distillate oil with an appropriate viscosity.
It can be prepared by refining this distillate oil by furfural extraction, hydrorefining, dewaxing treatment, and if necessary, clay treatment. The mineral oils obtained as described above are called 150 neutral oil, 500 neutral oil, bright stock oil, etc. In the present invention, these mineral oils are appropriately mixed, and if necessary, polyisobutylene,
The base oil is prepared by adding and mixing a thickener commonly used in lubricating oils, such as polybutene, to adjust its viscosity. Generally, 40℃ for industrial gear oil.
Kinematic viscosity at 60 to 680 cSt (centistokes)
Therefore, in the present invention as well, mineral oil having a kinematic viscosity within this range is used as the base oil. A mixture of the mineral oil and a synthetic oil known as a lubricating oil base oil, such as poly α-olefin, synthetic ester, etc., may be used as the base oil. The present invention provides the base oil with one or more selected from the group consisting of graphite, organic lead compounds, sulfurized orpheins, and metal-free alkyl phosphoric acid compounds, alkylthiophosphoric acid compounds, and alkyl dithiophosphoric acid compounds. It is characterized by a combination of two or more types. The graphite used in the present invention is usually used as a solid lubricant for lubricating oils, and has an average particle size of 1 μm or less. If the blending amount of graphite is less than 0.2 parts by weight based on 100 parts by weight of base oil, the improvement in wear resistance of gear oil and the smoothing effect on friction surfaces will not be observed.
It is necessary to mix 0.2 parts by weight with respect to 5 parts by weight, and on the other hand, if it exceeds 5 parts by weight, the improvement in performance will be small, which is uneconomical. The organic lead compounds used in the present invention are those conventionally used in gear oil, including lead stearate,
Examples may include lead soaps such as lead naphthenate, lead oleate, and lead dialkyldithiocarbamates. The appropriate amount of these organic lead compounds is 0.5 to 3.0 parts by weight per 100 parts by weight of the base oil.
If the amount is less than 0.5 part by weight, no improvement in wear resistance will be observed under extreme pressure conditions, and the effect of smoothing out roughness on the gear surface cannot be expected. Incidentally, even if the amount exceeds 3.0 parts by weight, it is not economically advantageous because the above effects cannot be further improved. In addition, the sulfurized olefin used in the present invention is a polysulfide with a sulfur content of 40 to 50 parts by weight obtained by sulfurizing a polymer of isoptylene, sulfurized Spine whale oil, and is an extreme pressure agent for conventional gear oil. The average molecular weight is approximately 500.
From the viewpoint of solubility in base oil, those having a molecular weight of from about 1,000 to about 1,000 are preferred. The amount of the sulfurized olefin and sulfurized whale oil is 0.3 to 2.0 parts by weight as sulfur content per 100 parts by weight of the base oil, and no improvement in wear resistance can be expected outside this range. Above 2.0 parts by weight, performance no longer improves. Incidentally, even when a disulfide-type organic sulfur compound is used as a sulfur additive, the wear resistance does not improve as with sulfurized olefin. Next, the metal-free alkylphosphoric acid compounds, alkylthiophosphoric acid compounds, and alkyldithiophosphoric acid compounds used in the present invention will be explained. Alkyl phosphoric acid compounds have the following formulas (), (),
() (R ₁ in the formula (), (), () represents a C ₈ - C ₁₂ alkyl group) or an alkyl amine salt (partially or a completely neutralized salt), such as a compound represented by the following formula (). ( _R2 in formula () represents a _C8 to _C12 alkyl group). The alkylthiophosphoric acid compound has the following formula ()
()()()(), phosphoric ester compounds of the same acidic esters, or alkylamine salts (partially or completely neutralized salts) thereof are applicable. (R ₁ in formulas (), (), (), () is C ₈ ~ _{C 12}
alkyl group, R ₃ is C ₃ divalent alkyl group, R ₄ is
each represents a _C8 to _C18 alkyl group). The alkyl dithiophosphoric acid compound has the following formula ()
This includes alkyl dithiophosphates represented by ~(), acidic phosphate ester compounds of the same esters, or alkylamine salts (partially or completely neutralized salts) thereof. (In formulas () to (), R ₁ represents a C ₈ to C ₁₂ alkyl group, R ₃ represents a C ₃ divalent alkyl group, and R ₄ represents a C ₈ to C ₁₈ alkyl group, respectively). The compounds represented by the above formulas () to () are used alone or in combination of two or more, and the compounding amount is 0.02 as a phosphorus content per 100 parts by weight of the base oil.
A suitable amount is 0.10 to 0.10 parts by weight. The upper limit of the amount of phosphorus added is determined by the relationship with the sulfur content of the coexisting sulfurized olefin, and the load-bearing performance is maximized when the sulfur content is approximately one-tenth of the equivalent. If too large a quantity is added, seizure may occur more easily. Further, the lower limit of the phosphorus content is determined from the viewpoint of abrasion resistance, and if it is less than 0.02 parts by weight, sufficient abrasion resistance cannot be maintained. Therefore, the reason why the amount of phosphorus added is set at 0.02 to 0.10 parts by weight is related to the fact that the sulfur content is set at 0.3 to 2.0 parts by weight. This is thought to be related to competitive adsorption of sulfur compounds and phosphorus compounds onto the lubricated metal surface and chemical reactions at extremely high temperatures. These phosphorus-containing compounds are conventionally used as extreme pressure agents for gear oils, such as
Anglamol99, Anglamol99LS, Anglamol6004
(Both Lubrizol products)
It is commercially available as Ortholeum 535 (a product of DuPont). Some of these contain sulfurized olefins. As mentioned above, among the substances added to the base oil in the present invention, all of the substances except graphite are known as additives for gear oil.
In the present invention, by combining these three known additives and graphite and blending it into the base oil,
As mentioned earlier, the conventional S-P system and Pb
- It becomes possible to provide an energy-saving industrial gear oil composition that can eliminate the drawbacks seen in S-based gear oils, significantly reduce the coefficient of friction and wear of gears, and smooth friction surfaces. Incidentally, if graphite is replaced with molybdenum disulfide or if the organic lead compound is removed from the composition of the present invention, the above object cannot be achieved. EXAMPLES The composition of the present invention and its effects will be specifically explained below with reference to Examples. Example 1 Preparation of base oil: A mixture of 500 neutral oil and bright stock oil having the properties shown in Table 1 below at a weight ratio of 6:94 was used as the base oil.

【table】

[Table] For 100 parts by weight of the above base oil, 0.5 parts by weight of graphite, 1.5 parts by weight of lead naphthenate, 0.8 parts by weight of sulfurized olefin, and phosphoric acid ester substituted with 1 to 2 dihexylthiophosphoric acid groups. A mixture of the alkylamine salt having 18 carbon atoms and the above alkylamine salt of a phosphoric acid ester substituted with 1 to 2 dihexylpropyl dithiophosphoric acid groups was added with 0.05 parts by weight of phosphorus and mixed to obtain gear oil 1. . Note that 98% of graphite has a particle size of 0.3 μm or less, and a commercially available additive (trade name: SLA1255, manufactured by Acheson KK, Japan) in the form shown below was used. The additive contains 10% by weight of graphite dispersed in 150 neutral oil as a carrier oil, and has the following properties: specific gravity: 0.93, viscosity: 27cst/98.9°C, color: black, flash point: 220°C. 1/20 part by weight of the additive containing graphite was added to 100 parts by weight of the base oil. Incidentally, if the particle size of graphite exceeds 1 μm, it will settle during storage, which is not practical. The properties of the obtained gear oil 1 are shown in Table 2.

[Table]
Example 2 In Example 1, lead naphthenate was replaced with 1.0 part by weight of lead diamyldithiocarbamate, 0.6 part by weight of sulfurized olefin, 0.05 part by weight of the phosphorus compound used in Example 1, and 0.05 part by weight of sulfur. A long chain (8 to 12 carbon atoms) of di- and mono-alkyl esters of acids (alkyl group is a mixture of 8 to 12 carbon atoms)
~12) Gear oil 2 was obtained in the same manner as in Example 1, except that 0.01 part by weight of the alkylamine salt was added to the base oil and mixed. The properties of the obtained gear oil 2 are shown in Table 2. Example 3 For 100 parts by weight of the base oil used in Example 1, 0.4 parts by weight of graphite (1/25 parts by weight of SLA1255), 1.0 parts by weight of lead naphthenate, 0.8 parts by weight of sulfurized olefin, and di- and phosphoric acid were added. Monoalkyl ester (mixture of alkyl groups having 8 to 12 carbon atoms) long chain (8 to 12 carbon atoms) alkylamine salt with phosphorus content of 0.01
Parts by weight, the main component is an alkylamine salt of a phosphoric acid ester represented by the above general formula () (R ₁ = mixture of C ₈ to C ₁₂ alkyl, R ₃ = isopropyl group, R ₄ = C ₁₈ alkyl group) Gear oil 3 was obtained by adding and mixing 0.05 parts by weight of a phosphorus compound. The properties of the obtained gear oil 3 are shown in Table 2. Comparative Example 1 For 100 parts by weight of the base oil used in Example 1, 1.5 parts by weight of lead naphthenate, 1.0 parts by weight of the sulfurized olefin as a sulfur content, and 0.05 parts by weight of the phosphorus compound used in Example 1 as a phosphorus content. Gear oil 4 was obtained by adding and mixing. Comparative Example 2 For 100 parts by weight of the base oil used in Example 1, 1.5 parts by weight of lead diamyldithiocarbamate, 0.8 parts by weight of sulfurized olefin as sulfur content, and 0.05 parts by weight of phosphorus compound used in Example 1 as sulfur content. 1 part by weight and 0.5 part by weight of molybdenum disulfide were added and mixed to obtain gear oil 5. The molybdenum disulfide used here is commercially available from Acheson KK Japan under the trade name SLA1246, and is used as a carrier oil.
Molybdenum disulfide (of its particle size) is added to neutral oil.
It contains 15% by weight of 98% of which is 0.3 μm or less) and has the following properties. Ratio Quantity 1.00 Viscosity 23cst/98.9℃ Color Tone Green-gray Flash Point 220℃ Comparative Example 3 100 parts by weight of the base oil used in Example 1, 0.5 parts by weight of graphite (1/20 parts by weight of SLA1255), sulfide Gear oil 6 was obtained by adding and mixing 0.8 parts by weight of olefin in terms of sulfur content and 0.05 parts by weight in terms of phosphorus content of the amine salt of the phosphorus compound used in Example 3. Comparative Example 4 For 100 parts by weight of the base oil used in Example 1, 0.8 parts by weight of the sulfurized olefin as a sulfur content, 0.05 parts by weight of the phosphorus compound used in Example 1 as a phosphorus content, and 1.5 parts by weight of zinc dialkyl dithiophosphate. Parts by weight were added and mixed to obtain gear oil 7. Next, each gear oil of Examples 1 to 3 and Comparative Examples 1 to 4 and the commercially available SP gear oil shown in Table 2 (phosphorus content 0.03 wt%, sulfur content 1.64 wt%)
A wear test was conducted using a Chimken type friction tester under the following conditions, and the wear scar width, friction coefficient, and surface roughness of the friction surface of the test block were measured. To measure the surface roughness, use the Kosaka Laboratory SE-3 type surface roughness meter. The roughness was converted into electrical output by scanning in the right angle direction, and the image was enlarged and displayed on recording paper. Test conditions: Test ring SUJ2 [Hv (10Kg) = 900] (manufactured by Chimken, USA) Test block SCM4 [Hv (10Kg) = 355] [manufactured by Nippon Test Panel Co., Ltd.] Rotation speed 520rpm Operating time 10 minutes Oil supply temperature 40 ℃ (Note) Hv: Indicates Bitkers hardness. The measurement results from the test are shown in Table 3 below and Figure 1. Incidentally, the Chimken type friction tester used in this test is manufactured by Shinko Zoki KK and is ASTMD2782 or
It is mechanically exactly the same as the Chimken extreme pressure testing machine specified in JISK2519-80, but whereas the Chimken extreme pressure testing machine can only operate at a rotation speed of 800 rpm, this testing machine can operate at a rotation speed of 500 to 4500 rpm. Its feature is that it can be shifted in stages.

[Table] As seen in Table 3 above, the gear oil according to the present invention has superior seizure resistance and wear resistance, and has a lower frictional force than the comparative examples and commercially available gear oils. The effect of blending graphite in the present invention is clear from the comparison between Examples 1 to 3 and Comparative Example 1, and the gear oil according to the present invention shows remarkable effects in both friction coefficients, while as a solid lubricant. When graphite was replaced with known molybdenum disulfide (Comparative Example 2), a rather bad effect was exhibited. In addition, the necessity of blending the organic lead compound in the present invention also applies to Examples 1 to 3 and Comparative Examples 3 and 4.
It is clear from the comparison of Figures 1a to 1h of the accompanying drawings show the results of measuring the friction surface condition of the test piece (block) after the above test at a lever load of 30 pounds using various gear oils. In the figure, a to c are gear oils of Examples 1 to 3, and d to g are comparative examples 1 to 3.
Regarding the gear oil No. 4, h is the value shown for the commercially available SP gear oil. As seen in the figure, it can be seen that when the gear oil according to the present invention was used, the surface of the test piece was smoother than that of the comparative example and the commercially available gear oil. Next, in order to confirm the energy-saving effect of the gear oil according to the present invention, the efficiency of the worm gear was examined using Example 1, Comparative Example 3, and commercially available SP-based gear oils. The specifications of the worm gear device used are as follows.

[Table] The efficiency of the worm gear was calculated using the following formula. Efficiency = Output torque x Output circuit speed/Input torque x Input rotational speed x 100 = Output torque/Input torque x Gear ratio x 100 (%) The results of the above test are shown in Figure 2. In addition, Fig. 2 shows the results of a test at an input torque of 1.00 kg·m, a rotational speed of 1800 rpm, and a gear ratio of 1/30. As seen in FIG. 2, it can be seen that the gear oil according to the present invention is a lubricating oil that exhibits higher efficiency than Comparative Example 3 and commercial products. In addition, the gear oil 2 shown in Example 2 and the commercially available S shown in Table 2 were also used.
-P-type gear oil was poured into the reducer of each large crane, and after operating for over 20 days to get the gear surface used, the power consumption of the crane was measured. The measurement results are shown in Table 4. The specifications of the large crane and reducer (three-stage reducer) used in the above operation are as shown in Table 5.

【table】

[Table] As shown in Table 4, when filled with gear oil 2, the power consumption is lower than that of conventional S-P type gear oil.
It is recognized that 12KW (approximately 5.8%) can be saved.

[Brief explanation of drawings]

Figure 1 shows the measurement results of the surface roughness of the wear marks on the test block after a friction test was conducted using a Chimken type friction tester using the gear oil according to the present invention, together with a comparison example. a to c are gear oils of Examples 1 to 3, and d to g, respectively.
indicates the gear oils of Comparative Examples 1 to 4, and h indicates the commercially available SP gear oils, respectively. FIG. 2 shows the efficiency of the gear oil according to the present invention in a worm gear in relation to the oil temperature, and also shows the efficiency of a comparative example and a commercially available product.

Claims (1)

[Claims] 1. For 100 parts by weight of base oil, 0.2 parts by weight or more of graphite, 0.5 to 3.0 parts by weight of organic lead compounds, 0.3 to 2.0 parts by weight of sulfurized olefin as a sulfur content, and alkyl phosphoric acid compounds, alkyl thiophosphoric acid compounds, and An industrial gear having excellent pitting resistance and wear resistance, characterized by containing 0.02 to 0.1 parts by weight of one or more selected from the group consisting of alkyl dithiophosphoric acid compounds as phosphorus. oil composition.