JP2904322B2 - Lubricating oil composition for hydraulic cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating oil composition for a hydraulic cylinder, and more particularly to a lubricating oil composition for a hydraulic cylinder used in a home elevator or the like.

[0002]

2. Description of the Related Art Recently, elevators are often required even in homes. This home elevator, that is, the elevator, is operated by the expansion and contraction of a hydraulic piston, which is a so-called hydraulic type. However, in order to improve ride comfort and from the viewpoint of construction accuracy, the piston is operated by a cylinder when stopping. It must be designed to stop short of its own stroke end. Therefore, the seal for preventing the hydraulic oil from leaking is always under pressure.

[0003] As a hydraulic oil used for a hydraulic cylinder having such characteristics, a conventional hydraulic hydraulic oil for a hydraulic cylinder has been conventionally used as it is.

However, if the conventional hydraulic oil is used for a long period of time, noise and vibration will occur. Sounds and vibrations are trapped in the elevator, causing discomfort to the user. One method for preventing such noise and vibration is to use a high-viscosity hydraulic oil. However, in this case, there is a problem that the viscosity is excessively increased in the winter season, and the speed at which the elevator is lowered is reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating oil composition for a hydraulic cylinder which can prevent generation of noise and vibration even if it has a low viscosity.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by adding a specific phosphorus compound to a lubricating base oil, the sound and noise can be increased without increasing the viscosity. It has been found that the generation of vibration can be prevented, and the present invention has been completed.

That is, the present invention relates to (A) a lubricating base oil,
(B) hydrocarbyl acid phosphate and / or hydrocarbyl phosphite, and (C)
An object of the present invention is to provide a lubricating oil composition for an elevator hydraulic cylinder, comprising oleic acid and / or oleylamine as essential components.

Hereinafter, the contents of the present invention will be described in more detail. The lubricating base oil (A) in the present invention is not particularly limited, and any of a mineral oil type and a synthetic type can be used as long as it is generally used as a base oil for lubricating oils. As a mineral oil-based lubricating oil, for example, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil, solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, Purified oils such as paraffinic and naphthenic oils, which are appropriately combined with purification treatments such as sulfuric acid washing and clay treatment, can be used. Examples of the synthetic lubricating oil include poly-α-olefins (polybutene, 1-octene oligomer,
Decene oligomers), alkylbenzenes, alkylnaphthalenes, diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di 2-ethylhexyl sebacate, etc.), polyol esters (trimethylolpropane caprylate, trimethylol) Propane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, polyphenyl ether, silicone oil, perfluoroalkyl ether and the like can be used. These base oils may be used alone or in combination of two or more. (A) The preferred kinematic viscosity of the lubricating base oil is 40
5 ° C. at 50 ° C., and a preferred aniline point is 60-100.

The component (B) in the present invention is a hydrocarbyl acid phosphate and / or a hydrocarbyl phosphite, and is preferably represented by the following formulas (I) to (IV). Things.

[0010]

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[0011]

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[0012]

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[0013]

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(In the above formula, R ^{1 to} R ⁶ may be the same or different and each represents a group selected from an alkyl group, an alkenyl group, an aryl group and an alkaryl group having 4 to 20 carbon atoms.)

As the component (B), specifically, for example,
Butyl acid phosphate, 2-ethylhexyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, oleyl acid phosphate,
Phenyl acid phosphate, dibutyl acid phosphate, di-2-ethylhexyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, dioleyl acid phosphate, diphenyl acid phosphate, butyl phosphorous acid Ester, 2-ethylhexyl phosphite, lauryl phosphite, stearyl phosphite, oleyl phosphite, phenyl phosphite, dibutyl phosphite, di-2-ethylhexyl phosphite, dilauryl Examples include phosphites, distearyl phosphites, dioleyl phosphites, diphenyl phosphites, and the like. Of course, two or more compounds having different structures may be used in combination.

The content of the component (B) in the composition of the present invention is optional, but if it is too small, the effect is not sufficient, and if it is too large, it is uneconomical. Specifically, it is desirably contained in an amount of 0.01 to 5.0% by weight, preferably 0.1 to 1.0% by weight based on the total amount of the composition.

In the present invention, excellent performance is obtained by using the above components (A) and (B).
In order to further enhance the performance, (C) a friction reducing agent can be contained. Examples of the component (C) include aliphatic amines, higher alcohols, higher fatty acids, fatty acid esters, fatty acid amides, molybdenum dithiophosphate, molybdenum dithiocarbamate, molybdenum disulfide, carbon fluoride, and borate esters. Aromatic amines, higher alcohols, higher fatty acids, fatty acid esters and fatty acid amides are preferably used. More specifically, aliphatic amines having 10 to 20 carbon atoms are preferably used, and examples thereof include laurylamine, myristylamine, palmitylamine, stearylamine, and oleylamine. Aliphatic amine alkylene oxide adducts obtained by adding alkylene oxides having 2 to 4 carbon atoms to these aliphatic amines are also preferably used. As the higher alcohol, one having 10 to 20 carbon atoms is preferably used, and examples thereof include lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and oleyl alcohol. As the higher fatty acid, those having 10 to 20 carbon atoms are preferably used. For example, lauric acid, myristic acid, palmitic acid,
Stearic acid, oleic acid and the like can be mentioned. Examples of the fatty acid esters include esters of fatty acids having 10 to 20 carbon atoms such as methyl laurate, methyl myristate, methyl palmitate, methyl stearate, and methyl oleate with lower alcohols, and fatty acid glycerides having 10 to 20 carbon atoms such as oils and fats. , 10 to 10 carbon atoms such as sorbitan monooleate
And 20 partial esters of fatty acids and polyhydric alcohols. As the fatty acid amide, those having 10 to 20 carbon atoms are preferably used, and examples thereof include laurylamide, myristylamide, palmitylamide, stearylamide, and oleylamide. Of course, two or more of the above compounds can be used in combination.

When the friction reducing agent (C) is contained in the composition of the present invention, its content is optional, but if the content is too small, the effect is not sufficient, and if it is too large, it is uneconomical. Specifically, it is desirably contained in an amount of 0.01 to 5.0% by weight, preferably 0.1 to 1.0% by weight based on the total amount of the composition.

In order to further enhance the excellent performance of the composition of the present invention, known additives can be used if necessary. Examples of the additive include extreme pressure agents such as tricresyl phosphate, triphenyl phosphate and zinc dithiophosphate, rust inhibitors such as petroleum sulfonate and dinonylnaphthalene sulfonate, metal deactivators such as benzotriazole, and alkaline earth metals. Metal detergents such as metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, alkaline earth metal phosphonates, ashless dispersants such as succinimide, succinate, benzylamine, diphenylamine, phenyl-
α-naphthylamine, 2,6-di-tert-butyl-
Antioxidants such as p-cresol, defoamers such as silicone, viscosity index improvers such as polymethacrylate, olefin copolymer, polyisobutylene, and polystyrene, pour point depressants, and the like. These may be used alone or in combination of two or more. It can be added together. The content of the viscosity index improver is usually 1 to 30% by weight, and the content of the defoamer is usually 0.0%.
005 to 1% by weight, the content of the metal deactivator is usually 0.1%.
005 to 1% by weight, and the content of other additives is usually 0.1 to 15% by weight (all based on the total amount of the composition).
It is.

[0020]

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

Examples 1-6 and Comparative Examples 1-6 Solvent refined mineral oil to which a viscosity index improver and an antioxidant were added was used as a lubricating base oil. The kinematic viscosity of this lubricating base oil was 14.5 cSt (＠ 40 ° C.), and the viscosity index was 210.

To the lubricating base oil, predetermined amounts of various additives shown in Tables 1 and 2 were added to prepare a lubricating oil composition.

(Evaluation Test) The lubricating oil composition of the present invention shown in Table 1 was used in the hydraulic cylinder of the elevator apparatus shown in FIG. 1 and was moved up and down 45 times / hr under a load of 0.65 t.
After the elapse of the evaluation period shown in (1), the occurrence of sound and vibration was evaluated. The results are also shown in Table 1. The lubricating oil composition for comparison shown in Table 2 was evaluated in the same manner as the lubricating oil composition of the present invention, and the results are also shown in Table 2.
In addition, in the presence or absence of generation of sound vibration of Tables 1-2,
"No ^a) " indicates that sound and vibration were at a satisfactory level, but were negligible.

[0024]

[Table 1]

[0025]

[Table 2]

As is clear from the results of the above Examples and Comparative Examples, the lubricating oil compositions of Examples 1 to 6 did not cause any problem in sound and vibration even after 12 months, whereas Comparative Example 1
Sound and vibration occurred in the lubricating oil compositions of Nos. 6 to 6.

[0027]

As described above, the lubricating oil composition for a hydraulic cylinder of the present invention can prevent generation of noise and vibration even at a low viscosity.

[Brief description of the drawings]

FIG. 1 is a view showing an elevator apparatus for evaluating a lubricating oil composition used in Examples and Comparative Examples.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 40:08 (72) Inventor Kazuhiro Nonome 505 Kayaba Kogyo Co., Ltd., Kagi City, Gifu Prefecture Gifu South Plant (56) References JP-A-1-319590 (JP, A) JP-A-58-201896 (JP, A) JP-A-4-314794 (JP, A) JP-A-5-331477 (JP, A) JP-A-5-255683 (JP JP, A) JP-A-5-331478 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 137/02 C10M 129/40 C10M 133/06 C10M 137/04 C10N 30: 00 C10N 40:08

Claims (1)

(57) [Claims] (1) A lubricant base oil containing (B) a hydrocarbyl acidic phosphate and / or a hydrocarbyl phosphite and (C) oleic acid and / or oleylamine as essential components. Lubricating oil composition for hydraulic cylinders of elevators.