JP2006152082A - Lubricant composition for rolling device, and rolling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant composition for a rolling device, hardly getting deterioration or the reduction of function, and suppressing the occurrence of seizing or abrasion in the rolling device, and also a rolling device excellent in lubricating property and having a long life. <P>SOLUTION: This deep groove ball bearing is equipped with an inner ring 1 having an orbit surface 1a on its outer circumferential surface, an outer ring 2 having an orbit surface 2a opposing to the orbit surface 1a and a multiple number of rolling bodies 3 arranged rollably between both of the orbit surfaces 1a, 2a. In a space formed between both of the orbit surfaces 1a, 2a and arranged with the rolling body 3, the lubricant composition 6 containing microcapsules including an additive is arranged. The lubricant composition 6 contains a base oil and the additive, and at least a part of the additive is contained as included in the microcapsules and the content of the additive included in the microcapsules is ≥10 mass% and ≤35 mass% based on the total of the lubricant composition 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricant composition suitable for a rolling device, and more particularly to a lubricating oil or grease. The present invention also relates to a rolling device such as a rolling bearing, a linear guide device, a ball screw, and a linear motion bearing.

In recent years, rolling devices used under high load and low speed conditions such as ball screws used in electric injection molding machines and rolling bearings used in continuous casting machines are used under severe conditions such as high temperature, high load, and high speed. More and more are being done. In addition, there is a growing demand for maintenance-free. For this reason, a higher-performance lubricant has been desired for the rolling device as described above.
On the other hand, in the lubrication of rolling bearings, the coefficient of friction between the two contacting metal surfaces varies depending on the absolute viscosity of the lubricating oil used, the bearing load, and the rotational speed. That is, in a completely lubricated state in which a thick oil film is formed between the friction surfaces, the contact between the two metal surfaces hardly occurs, so the friction coefficient is extremely small.

However, in a mixed lubrication state in which metal-metal contact is partially generated or in an environmental lubrication state in which the oil film is broken and metal-metal contact occurs, damage such as seizure may occur on the friction surface. In order to prevent such damage, additives such as an extreme pressure agent and an antiwear agent are added to the lubricant. And such an additive has the tendency for an addition effect to be high, if there is much addition amount.
JP 7-233362 A JP 2001-234188 A

However, if the amount of the additive added is large, the grease may be softened or chemically deteriorated, so it may be necessary to suppress the amount of additive added.
Accordingly, the present invention provides a lubricant composition for a rolling device that solves the above-described problems of the prior art, is less prone to deterioration and performance degradation, and suppresses seizure and wear on the rolling device. The issue is to provide. Another object is to provide a long-life rolling device with excellent lubricity.

  In order to solve the above problems, the present invention has the following configuration. That is, the rolling device lubricant composition of claim 1 according to the present invention is a rolling device lubricant composition containing a base oil and an additive, wherein at least a part of the additive is microscopic. The additive is contained in a capsule, and the content of the additive contained in the microcapsule is 10% by mass or more and 35% by mass or less of the entire composition.

  The lubricant composition for a rolling device of the present invention contains microcapsules encapsulating the additive, and the additive is isolated in the microcapsule. Therefore, even if the additive amount is increased, chemical deterioration hardly occurs in the lubricant composition for a rolling device (base oil or the like). That is, the lubricant composition for a rolling device according to the present invention can increase the amount of the additive, so that the effect of adding the additive is high and the performance is high.

Content of additives encapsulated in microcapsules (not including the mass of microcapsule walls and the mass of additives not encapsulated in microcapsules and added directly to the lubricant composition for rolling devices) Needs to be 10 mass% or more and 35 mass% or less of the whole lubricant composition for rolling devices.
If the amount is less than 10% by mass, the additive effect may be insufficient. On the other hand, when it exceeds 35 mass%, the amount (volume) of the microcapsules becomes excessive, and the fluidity of the lubricant composition for a rolling device may be insufficient. If the fluidity is insufficient, the rolling agent lubricant composition (microcapsule) does not reach the necessary site, and therefore the effect of adding the additive cannot be sufficiently obtained.

In addition, since the microcapsule is physically broken in the load zone of the rolling device, the contained additive is reliably supplied to the load zone. In a state where an oil film having a thickness equal to or larger than the particle size of the microcapsules is formed in the load zone, the microcapsules are not broken, so that no excess additive is released.
According to a second aspect of the present invention, there is provided the rolling device lubricant composition according to the first aspect of the present invention, wherein the rolling device lubricant composition is a semi-solid grease.

Since the additive is isolated in the microcapsule, the grease is difficult to soften even if the additive amount is increased.
Furthermore, the rolling device according to claim 3 of the present invention includes an inner member having a raceway surface on the outer surface, and a raceway surface facing the raceway surface of the inner member, and is disposed outward of the inner member. In a rolling device comprising an outer member that is formed and a plurality of rolling elements that are arranged so as to be able to roll between the raceway surfaces, a space formed between the raceway surfaces and in which the rolling elements are arranged The lubricant composition for a rolling device according to claim 1 or 2 is provided.

  Such a rolling device is excellent in lubricity and has a long life because it is provided with a lubricant composition that hardly causes deterioration and performance degradation and suppresses the seizure and wear of the rolling device. Such a rolling device can be particularly preferably used under high load and low speed conditions. Here, the high load is a load condition in which the dynamic equivalent load / basic dynamic load rating (P / C) is 0.08 or more, and the low speed is a speed condition in which the dmn value is 5000 or less.

The present invention can be applied to various rolling devices. For example, a rolling bearing, a ball screw, a linear guide device, a linear motion bearing, and the like.
In the present invention, the inner member includes an inner ring when the rolling device is a rolling bearing, a screw shaft when the ball screw is also used, a guide rail when the linear guide device is used, and a linear bearing. In the case, each means an axis. The outer member is an outer ring when the rolling device is a rolling bearing, a nut when it is a ball screw, a slider when it is a linear guide device, and an outer cylinder when it is also a linear bearing. Means each.

  Since the lubricant composition for a rolling device of the present invention contains the additive contained in the microcapsule, it is difficult to cause deterioration and performance deterioration, and suppresses seizure and wear on the rolling device. . In addition, the rolling device of the present invention is lubricated with a lubricant composition that is unlikely to cause deterioration and performance degradation and that suppresses seizure and wear of the rolling device, so that it has excellent lubricity and a long service life. is there.

DESCRIPTION OF EMBODIMENTS Embodiments of a lubricant composition for a rolling device and a rolling device according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a structure of a deep groove ball bearing which is an embodiment of a rolling device according to the present invention. This deep groove ball bearing has an inner ring 1 having a raceway surface 1a on the outer peripheral surface, an outer ring 2 having a raceway surface 2a facing the raceway surface 1a on the inner peripheral surface, and a raceway between the raceway surfaces 1a and 2a. A plurality of rolling elements (balls) 3, a cage 4 that holds the plurality of rolling elements 3 between the inner ring 1 and the outer ring 2, and a seal 5 that covers the opening of the gap between the inner ring 1 and the outer ring 2 And. The cage 4 and the seal 5 may not be provided.

In the space formed between the raceway surfaces 1a and 2a and in which the rolling elements 3 are arranged, a lubricant composition 6 containing microcapsules containing the additive is arranged, and both raceway surfaces 1a and 2a are arranged. And the rolling element 3 are lubricated.
This lubricant composition 6 contains a base oil and an additive, and at least a part of the additive is contained in the microcapsule, and the additive composition contained in the microcapsule. The content (not including the mass of the wall of the microcapsule) is 10% by mass or more and 35% by mass or less of the entire lubricant composition 6. It should be noted that all of the additives to be added to the lubricant composition 6 may be added in a state of being encapsulated in microcapsules. It may be added directly to product 6. The lubricant composition 6 may be a liquid lubricating oil or a semi-solid grease.

Below, the lubricant composition 6 of this embodiment is demonstrated in detail.
[About microcapsules]
Although the material which comprises a microcapsule is not specifically limited, The resin composition containing resin, such as a thermoplastic resin and a thermosetting resin, is preferable. Specific examples include polyurethane resin compositions, polyester resin compositions, polyamide resin compositions, polyurea resin compositions, phenol resin compositions, polyvinyl alcohol resin compositions, melamine resin compositions, and polyethylene resins. Examples thereof include a resin composition, a polystyrene resin composition, cellulose, and gelatin. Two or more kinds of microcapsules having different kinds of constituent materials and different particle sizes may be used in combination.

The method for producing the microcapsules is not particularly limited, and is selected in consideration of the nature of the additive that is the inclusion substance, the nature of the material constituting the microcapsule, and the like. Specific examples include an interfacial polymerization method, an in situ polymerization method, a phase separation method, a liquid drying method, an orifice method, a spray drying method, an air suspension coating method, a hybridizer method, and the like.
In addition, the microcapsules are preferably such that they are physically destroyed when they reach the load zone. For example, the microcapsules may be sensitive to temperature and destroyed at a predetermined temperature. . The microcapsules may be broken in response to light. Furthermore, the microcapsules may be broken in response to hydrogen ion concentration, metal ion concentration, or the concentration of a specific chemical substance.

[Additives]
The kind of the additive included in the microcapsule is not particularly limited, and an additive generally added to the lubricant can be used without any problem. For example, extreme pressure agent, antiwear agent, antioxidant, oiliness agent, rust inhibitor, metal corrosion inhibitor, antifoaming agent, colorant, solid lubricant, pour point depressant, viscosity index improver, cleaning dispersant Can be given.

  These additives may be used alone or in combination of two or more. When two or more additives are used in combination, a microcapsule in which a plurality of additives are encapsulated in one microcapsule may be used (however, it is preferable that the additives do not cause a chemical reaction). ), A plurality of microcapsules with different types of additives may be used in combination.

Examples of extreme pressure agents include metal dithiophosphates such as zinc dithiophosphate (Zn-DTP) and molybdenum dithiophosphate (Mo-DTP), zinc dithiocarbamate (Zn-DTC), and nickel dithiocarbamate (Ni-DTC). , Metal dithiocarbamate such as molybdenum dithiocarbamate (Mo-DTC).
Examples of the antiwear agent include regular phosphate esters, phosphite esters, acidic phosphate esters, phosphine, thiophosphate, and thiophosphite.

  Examples of orthophosphates include benzyl diphenyl phosphate, allyl diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, ethyl diphenyl phosphate, tributyl phosphate, dibutyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl. Phosphate, diethylphenylphenyl phosphate, propylphenyldiphenyl phosphate, dipropylphenylphenyl phosphate, triethylphenyl phosphate, tripropylphenyl phosphate, butylphenyl diphenyl phosphate, dibutylphenylphenyl phosphate, tributylphenyl phosphate, propylphenylphenyl phosphate mixture, Le phenyl phenyl phosphate mixtures thereof.

  As the phosphites, phosphorous diesters are preferable from the viewpoint of reactivity. For example, dibutyl hydrogen phosphite, di (nonylphenyl) hydrogen phosphite, dilauryl phosphite, ditetracosyl hydrogen phosphite Is given. Also, triphenyl phosphite, tri (p-cresyl) phosphite, tris (nonylphenyl) phosphite, triisooctyl phosphite, diphenylisodecyl phosphite, phenylisodecyl phosphite, triisodecyl phosphite, tristearyl Also suitable are phosphites, trioleyl phosphites, di-2-ethylhexyl hydrogen phosphites, dilauryl hydrogen phosphites and dioleyl hydrogen phosphites.

  Examples of the acidic phosphates include 2-ethylhexyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate, stearyl acid phosphate, isostearyl acid phosphate, oleyl acid phosphate, di-2-ethylhexyl phosphate. can give. As the antioxidant, anti-aging agents, ozone deterioration inhibitors, and antioxidants that are generally used for rubber, plastics, lubricating oils, and the like can be used without problems. Examples of such antioxidants include amine-based antioxidants, phenol-based antioxidants, dialkyldithiocarbamate compounds, and the like.

  Specific examples of the amine antioxidant include phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, alkyldiphenylamine, diphenyl-p-phenylenediamine, dipyridylamine, phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, 3,7-dioctylphenothiazine, p, p'-dioctyldiphenylamine, N, N'-di-2-naphthyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N'-diisopropyl- Examples thereof include p-phenylenediamine and N, N′-di-sec-butyl-p-phenylenediamine. Of these, phenyl-α-naphthylamine is particularly preferred.

Specific examples of the phenolic antioxidant include 2,6-di-tert-dibutylphenol and di-tert-butylcresol. Of these, 2,6-di-tert-dibutylphenol is particularly preferred.
Specific examples of dialkyldithiocarbamate compounds include zinc dialkyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, diethyldithiocarbamine. Examples include nickel oxide, nickel dibutyldithiocarbamate, copper dimethyldithiocarbamate, iron diethyldithiocarbamate, selenium diethyldithiocarbamate, telenium diethyldithiocarbamate, and zinc butylxanthate. Of these, zinc dialkyldithiocarbamate is particularly preferred.

[About base oil]
The kind of base oil of the lubricant composition 6 is not particularly limited, and any base oil generally used as a base oil for grease or lubricating oil can be used without any problem. However, the kinematic viscosity at 40 ° C. of the base oil is preferably 1 mm ² / s to 1500 mm ² / s. If it is less than 1 mm ² / s, it tends to evaporate, so that the deterioration of the lubricant composition tends to proceed, and if it exceeds 1500 mm ² / s, the shear resistance of the base oil is large, so it is not suitable for a rolling device.
Specific examples of the base oil include mineral oil, synthetic oil, and animal and vegetable oils. The mineral oil is preferably a mineral oil refined by appropriately combining vacuum distillation, solvent removal, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining, and the like.

  Synthetic oils include synthetic hydrocarbon oils, ester oils, ether oils and the like. Examples of the synthetic hydrocarbon oil include poly α-olefins such as normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, 1-decene and ethylene co-oligomer, and hydrogenated products thereof. Also suitable are alkylbenzenes such as monoalkylbenzene, dialkylbenzene and polyalkylbenzene, and alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene and polyalkylnaphthalene.

  Examples of ester oils include diester oils such as dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, methylacetyl ricinolate, and trioctyl trimellitate. Aromatic ester oils such as tate, tridecyl trimellitate, tetraoctyl pyromellitate and the like can be mentioned. Furthermore, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, mixed fatty acids of monobasic acids and dibasic acids and polyhydric alcohols Also suitable are complex ester oils which are oligoesters of

  Furthermore, as ether oil, for example, polyglycol such as polyethylene glycol, polypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, monoalkyl triphenyl ether, alkyl diphenyl ether, dialkyl diphenyl ether, tetraphenyl ether, pentaphenyl ether, Examples thereof include phenyl ether oils such as monoalkyl tetraphenyl ether and dialkyl tetraphenyl ether.

Examples of synthetic oils other than the above include tricresyl phosphate, silicone oil, and perfluoroalkyl ether oil.
Examples of animal and vegetable oils include beef fat, pork fat, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, and other oils and hydrides thereof.
These base oils may be used alone or in combination of two or more.

[About thickener]
If the lubricant composition is grease, it is necessary to use a thickener. The type of the thickener is not particularly limited, and can be appropriately selected depending on the application and use conditions. For example, metal soap (metal is aluminum, barium, calcium, lithium, sodium, etc.) and metal composite soap (metal is lithium, calcium, aluminum, etc.) can be mentioned. Urea compounds (diurea, triurea, tetraurea, polyurea, etc.), inorganic compounds (silica gel, bentonite, etc.), urethane compounds, urea / urethane compounds, sodium terephthalamate compounds, fluororesins, and the like can also be used.

  The grease penetration is preferably 150 to 400. If the penetration is over 400, the grease will be too soft, so it will flow during the driving of the rolling device, and part of it will adhere to the raceway surface, restricting the rotation of the rolling element and causing slippage. May cause this. On the other hand, if it is less than 150, the fluidity is inferior, and there is a possibility that the part where the grease is required does not reach and the microcapsule does not reach the part.

In addition, grease is often heated during the manufacturing process, and since it is rarely supplied continuously during use, a certain degree of heat resistance is required. Therefore, the kinematic viscosity at 40 ° C. of the base oil is preferably 15 mm ² / s or more. However, if it exceeds 1500 mm ² / s, the shear resistance of the base oil is large, which makes it unsuitable for a rolling device.
In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment.

For example, in the present embodiment, a deep groove ball bearing has been described as an example of a rolling device, but the present invention can be applied to various types of rolling bearings. For example, radial type rolling bearings such as angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust types such as thrust ball bearings and thrust roller bearings This is a rolling bearing.
The present invention can be applied not only to rolling bearings but also to various other types of rolling devices. For example, a ball screw, a linear guide device, a linear motion bearing, or the like.

〔Example〕
Hereinafter, the present invention will be described more specifically with reference to examples. First, the manufacturing method of the microcapsule which encloses an additive is shown.
Triethanolamine 3.3 g and styrene maleic anhydride copolymer 16.4 g were mixed and stirred for 2 hours, and water was added to prepare a copolymer aqueous solution having a pH of 5.0. To 25 g of this aqueous copolymer solution, 25 g of zinc dithiophosphate (Zn-DTP) as an additive was added and emulsified by stirring for 2 minutes using a homomixer to prepare an emulsion.

  Triethanolamine was added to 420 g of 25% glutaraldehyde aqueous solution to adjust the pH to 8.0, and then 25 g of melamine was added with stirring at 70 ° C. When the melamine was dissolved and the aqueous solution became transparent, this aqueous solution was added to the above emulsion with vigorous stirring. Then, since the methylolated melamine is polymerized around the additive by the action of the above-mentioned copolymer, the additive is wrapped in the polymer. And the wall body which consists of a polymer was hardened by heating at 70 degreeC for about 3 hours, and the microcapsule which encloses an additive was obtained. 50% of the total mass of the microcapsule was the mass of the encapsulated additive. Moreover, the average particle diameter of the obtained microcapsules was 5.0 μm.

The microcapsules thus obtained were added to grease containing ester oil (kinematic viscosity at 40 ° C. of 33 mm ² / s) and lithium 12-hydroxystearate. Various greases with different Zn-DTP contents (not including the mass of the microcapsule wall) are adjusted by changing the amount of microcapsules added, and these greases are used in plastic cages and contact rubber seals. Were encapsulated in the internal spaces of deep groove ball bearings (inner diameter 17 mm, outer diameter 52 mm, width 16 mm).

These deep groove ball bearings were subjected to a rotation test under the following high load and low speed conditions to evaluate the seizure resistance. That is, the deep groove ball bearing was loaded with a radial load of 196 N and an axial load of 1960 N, and was rotated at a rotational speed of 100 min ⁻¹ in an environment at an ambient temperature of 120 ° C. Then, when the outer ring temperature during rotation was measured and the outer ring temperature increased from 120 ° C to 140 ° C, or when the bearing torque increased and motor overcurrent occurred, seizure occurred and the life was reached. Judgment was made, and the rotation time up to that point was defined as the seizure life.

The results are shown in the graph of FIG. The seizure life values shown in this graph are the seizure life of deep groove ball bearings filled with grease directly added with Zn-DTP without adding microcapsules (indicated by white circles in the graph of FIG. 2). It is shown as a relative value when 1 is set to 1.
As can be seen from the graph, when the content of Zn-DTP was 10, 12, 30, 35% by mass, the seizure life was excellent. On the other hand, when the content of Zn-DTP was 8 and 40% by mass, the seizure life was the same level as when Zn-DTP was added directly.

It is a longitudinal cross-sectional view which shows the structure of the deep groove ball bearing which is one Embodiment of the rolling device which concerns on this invention. It is a graph which shows the correlation with content of Zn-DTP in grease, and the seizure life of a deep groove ball bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Raceway surface 2 Outer ring 2a Raceway surface 3 Rolling element 6 Lubricant composition

Claims (3)

  In a lubricant composition for a rolling device containing a base oil and an additive, at least a part of the additive is contained in a microcapsule, and the additive contained in the microcapsule is contained. The lubricant composition for a rolling device, wherein the content is 10% by mass or more and 35% by mass or less of the entire composition.   The lubricant composition for a rolling device according to claim 1, wherein the lubricant composition is a semi-solid grease.   An inner member having a raceway surface on the outer surface, an outer member having a raceway surface opposite to the raceway surface of the inner member, and arranged on the outer side of the inner member, and rolling between the both raceway surfaces A rolling device comprising a plurality of freely arranged rolling elements, wherein the rolling device according to claim 1 or 2 is provided in a space formed between the raceway surfaces and arranged with the rolling elements. A rolling device comprising a lubricant composition.

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