JP2006233080A - Lubricant composition and rolling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant composition which is capable of imparting to a rolling device the excellent seizing resistance, wear resistance and durability, and to provide a rolling device having the excellent seizing resistance, wear resistance and durability. <P>SOLUTION: The lubricant composition that contains the microcapsule having microparticles included, is used for the lubrication between the both track surfaces 1a and 2a and a rolling body 3 in a deep-groove roll bearing, with the microparticle being covered with an adsorptive resin having an easy-to-deposit property on at least one of the track surface 1a, the track surface 2a and the rolling surface 3a of the rolling body 3, with the lubricant composition having a content of the microcapsule of 0.01-20% by mass, and with the microcapsule having a particle diameter of 0.02-10 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricant composition. 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, various rotating devices and the like are often used under severe conditions such as high temperature, high load, and high speed as the size and weight are reduced and the speed is increased. In addition, there is a growing demand for maintenance-free. For this reason, a higher-performance lubricant (lubricating oil, grease) used in various rotating devices has been desired.
Japanese Patent Laid-Open No. 2005-8744

However, for example, when a conventional lubricant as in Patent Document 1 is used under the severe conditions as described above, there are cases where the seizure resistance, the wear resistance, or the durability is insufficient.
Accordingly, the present invention provides a lubricant composition that solves the problems of the prior art as described above and can impart excellent seizure resistance, wear resistance, and durability to a rolling device. This is the issue. Another object is to provide a rolling device having excellent seizure resistance, wear resistance, and durability.

  In order to solve the above problems, the present invention has the following configuration. That is, the lubricant composition of claim 1 according to the present invention has an inner member having a raceway surface on the outer surface, and a raceway surface opposite to the raceway surface of the inner member, on the outer side of the inner member. Lubricant composition containing microcapsules used for lubrication of a rolling device comprising an outer member arranged and a plurality of rolling elements arranged so as to roll between both raceway surfaces and enclosing fine particles In the object, the fine particles are covered with an adsorbent resin having a property of easily adhering to at least one of the raceway surface of the inner member, the raceway surface of the outer member, and the rolling surface of the rolling element. It is characterized by that.

  With such a configuration, the microcapsules are physically destroyed in the load zone of the rolling device (contact portion between the raceway surface and the rolling element), so that the fine particles are reliably supplied to the load zone. Then, the fine particles adhere to the raceway surface and the rolling surface, and the fine particle film is easily formed. For this reason, the direct contact between the raceway surface and the rolling element is less likely to occur, and the occurrence of damage such as wear and seizure is suppressed. Since the microcapsules are not destroyed outside the load zone, the fine particles are reliably supplied only to the load zone.

In addition, since the fine particles are contained in the lubricant composition in a state of being isolated in the microcapsules, there is a disadvantage that the penetration of the lubricant composition is lowered when the fine particles are added to the lubricant composition as they are. Hard to occur. Since the microcapsule has a higher affinity with the lubricant composition than the fine particles, the influence on the blending degree is small.
The adsorptive resin imparts to the fine particles a property that easily adheres to at least one of the raceway surface of the inner member, the raceway surface of the outer member, and the rolling surface of the rolling element. The coating makes it easier for the fine particles to adhere than when not covered with the adsorptive resin.

The lubricant composition according to claim 2 of the present invention is the lubricant composition according to claim 1, wherein the content of the microcapsules is 0.01% by mass or more and 20% by mass or less. And
When the content of the microcapsules in the lubricant composition is less than 0.01% by mass, the amount of fine particles becomes insufficient, and the above-described addition effect may not be sufficiently obtained. On the other hand, if the amount is more than 20% by mass, the amount of microcapsules is too large, and the lubricity of the lubricant composition may be insufficient.

Furthermore, the lubricant composition according to claim 3 according to the present invention is the lubricant composition according to claim 1 or 2, wherein the particle size of the microcapsules is 0.02 μm or more and 10 μm or less. And
If the particle size of the microcapsule is less than 0.02 μm, the microcapsule is less likely to be destroyed in the load zone of the rolling device, and thus the above-described effect of adding fine particles may not be sufficiently obtained. Moreover, since the particle size is small, the penetration of the lubricant composition may be reduced (the microcapsule has a thickening effect). On the other hand, if it exceeds 10 μm, it may act as a foreign substance in the load zone of the rolling device. In addition, it is difficult to stably disperse the lubricant composition, and the microcapsules are often destroyed in a portion other than the load zone of the rolling device.

Furthermore, the lubricant composition of claim 4 according to the present invention has an inner member having a raceway surface on the outer surface, and a raceway surface opposite to the raceway surface of the inner member, outward of the inner member. A rolling member comprising: an outer member arranged; a plurality of rolling elements arranged to roll between the both raceway surfaces; and a lubricant that lubricates between the raceway surfaces and the rolling elements. In the apparatus, the lubricant is the lubricant composition according to any one of claims 1 to 3.
Since such a rolling device is lubricated with the lubricant composition as described above, it has excellent seizure resistance, wear resistance, and durability.

The present invention can be applied to various rolling devices such as a rolling bearing, a linear guide device, a ball screw, and a linear motion bearing.
Here, the inner member in the present invention refers to 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 the outer ring when the rolling device is a rolling bearing, the nut when it is a ball screw, the slider when it is a linear guide device, and the outer cylinder when it is also a linear bearing. Each means.

  The lubricant composition of the present invention can impart excellent seizure resistance, wear resistance, and durability to a rolling device. Further, the rolling device of the present invention has excellent seizure resistance, wear resistance, and durability.

DESCRIPTION OF EMBODIMENTS Embodiments of a lubricant composition 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, and a cage 4 that holds the plurality of rolling elements 3 between the inner ring 1 and the outer ring 2. A lubricant composition (not shown) is supplied into a gap 5 formed between the inner ring 1 and the outer ring 2 and provided with a rolling element 3, and between the raceway surfaces 1 a and 2 a and the rolling element 3. The lubrication is performed. In addition, the holder | retainer 4 does not need to be provided.

  This lubricant composition contains a base oil and microcapsules enclosing fine particles, and the fine particles are at least one of the raceway surface 1 a, the raceway surface 2 a, and the rolling surface 3 a of the rolling element 3. It is covered with an adsorptive resin having the property of easily adhering to the surface. The microparticles are usually isolated in the microcapsule, but when the lubricant composition reaches the load zone of the deep groove ball bearing (the contact portion between the raceway surfaces 1a and 2a and the rolling element 3), the microcapsule It is physically destroyed and fine particles are released and supplied to the load zone.

  The content of the microcapsules in the lubricant composition (the content calculated by including the mass of the encapsulated fine particles in the mass of the microcapsules) is 0.01% by mass or more and 20% by mass or less. The mass ratio of the fine particles to the mass of the entire microcapsule is preferably 1% by mass or more and 90% by mass or less. The particle size of the microcapsule is 0.02 μm or more and 10 μm or less. Furthermore, the lubricant composition may be a liquid lubricating oil or a semi-solid grease.

Below, the lubricant composition of this embodiment is demonstrated in detail.
[About fine particles]
The type of fine particles encapsulated in the microcapsule is not particularly limited, but considering stability and ease of production, silicon, magnesium, calcium, barium, yttrium, titanium, zirconium, vanadium, niobium, chromium, An oxide, nitride, or carbide containing one or more metal elements selected from molybdenum, tungsten, manganese, cobalt, nickel, copper, zinc, aluminum, tin, lead, antimony, and bismuth is preferable.

The particle diameter of the fine particles is preferably 3 nm or more and 1 μm or less, and more preferably 3 nm or more and 100 nm or less. Fine particles exceeding 1 μm may act as abrasive grains and promote wear.
As a method for producing the fine particles, a known method can be employed without any problem, and examples thereof include a physical method such as a gas evaporation method, and a chemical method such as a precipitation method and a hydrolysis method. In the gas evaporation method, for example, an arc discharge is generated between a pair of electrodes made of metal (for example, aluminum) in an atmosphere in which a small amount of oxygen gas is mixed in an inert gas, thereby generating a metal oxide (for example, This is a method for producing fine particles of Al ₂ O ₃ ). The hydrolysis method is, for example, a method of generating metal oxide fine particles by hydrolyzing metal alkoxide, alum, metal sulfate, or metal chloride.

[Adsorbent resin]
The type of the adsorbent resin is not particularly limited as long as it can impart to the fine particles a property that easily adheres to at least one of the raceway surface of the inner ring, the raceway surface of the outer ring, and the rolling surface of the rolling element. A specific example is phenol resin. By coating the adsorbent resin, the fine particles are more likely to adhere to at least one of the raceway surface of the inner member, the raceway surface of the outer member, and the rolling surface of the rolling element than before coating.

[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-based resin compositions, polyester-based resin compositions, polyamide-based resin compositions, polyurea-based resin compositions, phenol-based resin compositions, polyvinyl alcohol-based resin compositions, and melamine-based resin compositions. It is done. These resins are particularly preferably adsorptive resins having a property that they easily adhere to at least one of the raceway surface of the inner ring, the raceway surface of the outer ring, and the rolling surface of the rolling element.

The method for producing the microcapsules is not particularly limited, and is selected in consideration of the properties of the encapsulated fine particles, the properties of the material constituting the microcapsules, 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 order to produce a microcapsule having a uniform particle size, it is preferable to appropriately adjust the production conditions of the microcapsule, but the microcapsule having a particle size distribution has a uniform particle size by a centrifugal separation method or a filter method. Microcapsules may be separated.

[About base oil]
The type of base oil of the lubricant composition is not particularly limited, and can be used without any problem as long as it is generally used as a base oil for lubricating oil and grease.
Specific examples of the base oil include mineral oil, synthetic oil, and animal and vegetable oils. Mineral oil refined to a viscosity index of 100 or more by appropriately combining vacuum distillation, solvent removal, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining, etc. preferable. And what is called highly refined mineral oil refine | purified so that a viscosity index may be 120 or more is more preferable.

Synthetic oils include synthetic hydrocarbon oils, ester oils, ether oils, silicone oils, fluorine 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 hydrides thereof. Further, alkylbenzenes such as monoalkylbenzene, dialkylbenzene, and polyalkylbenzene, and alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene are also included.

  The ester oils include dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, methyl acetyl ricinolate and the like, trioctyl trimellitate, tri Aromatic ester oils such as decyl trimellitate and tetraoctyl pyromellitate, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate Examples thereof include complex ester oils, which are oligoesters of mixed fatty acids of basic and dibasic acids and polyhydric alcohols.

  Further, as ether oils, polyglycols 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, monoalkyl tetra Examples thereof include phenyl ether oils such as phenyl ether and dialkyl tetraphenyl ether.

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

When the lubricant composition is a liquid lubricating oil, the kinematic viscosity of the base oil at 40 ° C. is preferably 1 mm ² / s to 400 mm ² / s. If it is less than 1 mm ² / s, evaporation or the like increases, so that wear of the lubricating oil is large. If it exceeds 400 mm ² / s, the shear resistance of the base oil becomes too large, so that it is not suitable for a rolling device.
In addition, when the lubricant composition is a semi-solid grease, the grease penetration is preferably 150 to 400, and the base oil has a kinematic viscosity at 40 ° C. of 15 mm ² / s to 400 mm. ² / s or less is preferable.

If the penetration is less than 150, the grease is too hard and poor in fluidity. If the fluidity is inferior, the grease does not reach the place where the grease is required, so the microcapsule does not reach the place and the effect of adding fine particles becomes insufficient. On the other hand, if the blending degree exceeds 400, the fluidity becomes excessive, so that the grease leaks from a necessary portion, and the effect of adding fine particles becomes insufficient.
In the case of grease, it is often heated in 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 400 mm ² / s, the shear resistance of the base oil becomes too large, so that it is not suitable for a rolling device.

[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.

[Additives]
Various additives generally used for lubricants can be used in the lubricant composition. In particular, extreme pressure agents, antioxidants, rust inhibitors, and metal corrosion inhibitors are preferred. Further, if necessary, an antifoaming agent, a colorant, a solid lubricant, a pour point depressant, a viscosity index improver, a cleaning dispersant and the like may be used. These additives may be used alone or in appropriate combination of two or more.

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, a method for manufacturing a microcapsule will be described. By using colloidal silica having a primary particle size of 13 nm as fine particles and using phenol resin as the adsorptive resin, microcapsules enclosing colloidal silica coated with phenol resin were obtained by an underwater drying method. At this time, the particle size of the microcapsules was adjusted by the W dispersion concentration of the W / O emulsion, the stirring speed, and the pressure.
Various urea greases containing the microcapsules thus obtained were prepared. Then, a rolling bearing with a nominal number of 6303DD in which 1.5 g of urea grease was sealed was prepared, and a rotation test was performed to evaluate its seizure resistance and wear resistance.

[Evaluation method for seizure resistance]
The rolling bearing described above was mounted on a testing machine similar to the bearing life testing machine defined in ASTM D1741, and rotated under conditions of a temperature of 140 ° C., a radial load of 98 N, and a rotational speed of 20000 min ⁻¹ . And the time until the drive motor which rotates a rolling bearing stops by an overload, or bearing temperature exceeds 155 degreeC was measured. Ten rotation tests were performed for each type of rolling bearing, and the average value was defined as the seizure life.

Next, the urea grease used for evaluation of seizure resistance will be described. The base oil of urea grease is a synthetic hydrocarbon oil having a kinematic viscosity of 48 mm ² / s at 40 ° C., and the thickener is a urea compound. And content of a microcapsule is 0 mass%, 0.001 mass%, 0.01 mass%, 0.1 mass%, 1 mass%, 10 mass%, 20 mass%, and 30 mass%, respectively.

  The evaluation results of seizure resistance are shown in the graph of FIG. Note that the numerical value of the seizure life shown in this graph is a relative value when the seizure life of a rolling bearing encapsulating urea grease in which the content of microcapsules is 0% by mass is set to 1. As can be seen from the graph of FIG. 2, when the content of the microcapsules in the urea grease is 0.01% by mass or more and 20% by mass or less, the seizure life of the rolling bearing is excellent.

[Abrasion resistance evaluation method]
A rolling bearing similar to that described above was mounted on the test machine described above and rotated under conditions of a temperature of 160 ° C., a radial load of 1666 N, an axial load of 490 N, and a rotational speed of 20000 min ⁻¹ . Then, after rotating for 200 hours, the iron content in the grease was quantified by atomic absorption analysis. Ten rotation tests were performed for each type of test bearing, and the average value was defined as the amount of wear.

Next, the urea grease used for the evaluation of wear resistance will be described. The base oil of urea grease is an ether oil having a kinematic viscosity at 40 ° C. of 100 mm ² / s, and the thickener is a urea compound. The content of the microcapsules is 1% by mass, and the particle diameters of the microcapsules are 0.02 μm, 0.1 μm, 1 μm, 10 μm, and 20 μm, respectively.

  The evaluation results of the wear resistance are shown in the graph of FIG. In addition, the numerical value of the amount of wear shown in this graph is shown as a relative value when the amount of wear of a rolling bearing encapsulating urea grease in which the content of microcapsules is 0% by mass is set to 1. As can be seen from the graph of FIG. 3, when the particle size of the microcapsule is 0.02 μm or more and 10 μm or less, the wear amount of the rolling bearing is small.

It is a longitudinal section showing the composition of the deep groove ball bearing which is one embodiment of the rolling device concerning the present invention. It is a graph which shows the correlation with content of a microcapsule, and a seizure lifetime. It is a graph which shows the correlation with the particle size and wear amount of a microcapsule.

Explanation of symbols

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

Claims (4)

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 In a lubricant composition containing a microcapsule that is used for lubrication of a rolling device including a plurality of freely arranged rolling elements and encloses fine particles,
The fine particles are covered with an adsorptive resin having a property of easily adhering to at least one of the raceway surface of the inner member, the raceway surface of the outer member, and the rolling surface of the rolling element. A lubricant composition.   The lubricant composition according to claim 1, wherein the content of the microcapsules is 0.01% by mass or more and 20% by mass or less.   The lubricant composition according to claim 1 or 2, wherein a particle size of the microcapsule is 0.02 µm or more and 10 µm or less.   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 and a lubricant that lubricates between the raceway surfaces and the rolling elements, wherein the lubricant is any one of claims 1 to 3. A rolling device comprising the lubricant composition according to item.

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