JP5808181B2 - Rolling bearing for wind power generator - Google Patents

Description

  The present invention relates to a rolling bearing for a wind power generator that is incorporated and used in a wind power generator and is grease lubricated.

  A rolling bearing, particularly a large double row roller bearing as shown in FIG. 2, is often used as a spindle support bearing in a large wind power generator. The rotor shaft (main shaft) 3 is a shaft to which the rotor blade 2 is attached. The rotor shaft (main shaft) 3 is rotated by receiving wind force, and the rotation is increased by the speed increaser 6 to rotate the generator 7 to generate power. When generating electricity by receiving wind, the rotor shaft 3 that supports the rotor blade 2 is loaded with an axial load (bearing axial load) due to wind force applied to the rotor blade 2 and an axial radial direction (bearing radial load). . In the wind turbine generator, a blade bearing used for a blade pitch swivel seat, a yaw bearing used for a yaw swivel seat, and the like are used. The blade bearing is a bearing that is attached to the base of the blade and rotatably supports the blade so that the angle of the blade can be adjusted by the strength of the wind in order to receive wind efficiently. The yaw bearing is a bearing that rotatably supports the yaw of the nacelle in order to adjust the direction of the main shaft in accordance with the wind direction.

  The above spindle support bearings, blade bearings, yaw bearings, etc. are operated in an environment where the wind direction and wind force are constantly changing. Wear phenomenon (hereinafter referred to as fretting) may occur. In particular, in the spindle support bearing, in addition to irregularly repeating start, acceleration, deceleration, and stop while constantly receiving fluctuations in load, blade vibration and gearbox vibration are added, and therefore there is a high possibility of causing fretting. In addition, in wind power generators installed on the mountain or in extremely cold regions and exposed to extremely low temperatures, the grease hardens and the supply of lubricating oil to the rolling surface cannot be obtained, resulting in increased fretting damage. There is a fear.

  Conventionally, various methods have been proposed to prevent such fretting, and one of them is a method for preventing fretting by selecting an appropriate lubricant. Among them, a grease in which at least one selected from oxidized paraffin, diphenyl hydrogen phosphite, and hexamethylphosphoric triamide is added to a urea-based thickener has been proposed (see Patent Document 1).

Japanese Patent No. 2576898

  However, the grease disclosed in Patent Document 1 is used by being incorporated in a wind power generator, and the wind direction and the wind force constantly fluctuate, and sufficient fretting prevention is achieved in a rolling bearing to which repeated swinging or the like depending on the strength or direction of the wind is applied. This is considered difficult.

  In addition, the effect of improving the fretting resistance by the grease used for lubrication has not been fully elucidated. For example, even greases containing the same thickener may give conflicting results for fretting resistance depending on the test method. In addition, there are many reports that additives containing phosphorus compounds such as phosphates and phosphate esters are preferable, but their fretting resistance varies greatly depending on the structure of the phosphorus compound.

  The present invention has been made to cope with such problems, and is used in a wind power generator and is used in an environment in which repeated swinging according to the strength and direction of the wind is applied. An object of the present invention is to provide a rolling bearing for a wind turbine generator that has fretting properties and can prevent wear on a rolling surface of a bearing.

（式（１）（２）において、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５は、それぞれメチル基またはエチル基である。また、Ｒ_１とＲ_２とは、Ｒ_３とＲ_４とＲ_５とは、同一の基であっても異なる基であってもよい。） A rolling bearing for a wind power generator according to the present invention is a bearing incorporated in a wind power generator, and the bearing is configured by rolling a plurality of rolling elements between an inner ring and an outer ring. In a space formed between the outer rings and in which the rolling elements are disposed, a grease composition containing a base oil, a thickener, and an additive is enclosed, and the base oil is a synthetic oil, and The kinematic viscosity at 40 ° C. is 300 to 600 mm ² / s, and the additive contains at least one phosphite represented by the formula (1) or (2), Content is 0.5-4 weight part with respect to 100 weight part of total amounts of the said base oil and the said thickener, It is characterized by the above-mentioned. The kinematic viscosity of the base oil is a kinematic viscosity measured according to JIS K 2283.

(In Formulas (1) and (2), R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each a methyl group or an ethyl group. R ₁ and R ₂ are R ₃ and R ₄ , respectively. And R ₅ may be the same group or different groups.)

  The grease composition is characterized by not containing a phosphite other than those represented by the formula (1) or (2) and a phosphate ester having an organic group having 3 or more carbon atoms.

  The phosphite is dimethyl phosphite, diethyl phosphite, trimethyl phosphite, or triethyl phosphite.

  The thickener is at least one selected from lithium soap and a urea compound.

  The grease composition has a blending degree of 200 to 350.

  The rolling bearing for wind power generator is a deep groove ball bearing, a roller bearing, or an angular ball bearing.

  The rolling bearing for wind power generator is a bearing that supports a main shaft, a blade, or a yaw of the wind power generator.

The rolling bearing for wind power generator of the present invention uses a base oil (synthetic oil) having a kinematic viscosity at 40 ° C. of 300 to 600 mm ² / s for the grease composition to be enclosed, and among the phosphites as an additive, In particular, by using a composition in which a predetermined amount of the one represented by the above formula (1) or formula (2) is used, it has excellent fretting resistance while being used in an environment in which repeated oscillations are applied, It is possible to prevent fretting on the rolling surface of the bearing in a wide temperature range.

  For this reason, the rolling bearing for wind power generators of this invention can be utilized suitably as a bearing which supports the main shaft, blade, or yaw of the wind power generator.

It is a schematic diagram of the whole wind power generator to which the rolling bearing for wind power generators of this invention is applied. It is a figure which shows the detail of the main shaft support part of FIG. It is sectional drawing which shows the double row self-aligning roller bearing for spindle support which is an example of the rolling bearing for wind power generators of this invention. It is sectional drawing which shows the deep groove ball bearing which is another example of the rolling bearing for wind power generators of this invention.

  A wind power generator to which a rolling bearing for wind power generator of the present invention is applied will be described with reference to FIGS. FIG. 1 is a schematic diagram of the entire wind power generator, and FIG. 2 is a diagram showing details of a main shaft support portion of FIG. As shown in FIG. 1, a wind turbine generator 1 includes a rotor blade 2, a generator 7 driven via a speed increaser 6 attached to a rotor shaft (main shaft) 3 of the rotor blade 2, and a rotor blade. 2 and a tower 8 that holds the nacelle 4 containing the speed increaser 6 and the generator 7 at a predetermined height. The rotor 7 receives the wind and rotates to drive the generator 7 and take it out as electric energy. As shown in FIG. 2, the rotor shaft 3 to which the rotor blade 2 is attached is rotatably supported by a bearing 5 installed in a bearing housing 15 in the nacelle 4. The bearing 5 is a rolling bearing for a wind power generator according to the present invention. In addition, although the bearing 5 is provided in the example of FIG. 2, it may be one.

  The speed increaser 6 increases the rotation of the rotor shaft 3 and transmits it to the input shaft of the generator 7. The nacelle 4 is installed on the tower 8 via a yaw swivel seat bearing 17 so as to be rotatable, and is turned via a speed reducer 10 by driving a turning motor 9 shown in FIG. The turning of the nacelle 4 is performed in order to adjust the direction of the rotor blade 2. Further, a rolling bearing (not shown) is provided on the blade pitch swivel seat at the base of the rotor blade 2.

  The bearing 5 for supporting the main shaft will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a bearing for supporting a main shaft, which is an example of a rolling bearing for a wind power generator according to the present invention. The bearing 5 is a double row self-aligning roller bearing. The bearing 5 includes an inner ring 11 and an outer ring 12 that are a pair of race rings, and a plurality of rolling elements 13 interposed between the inner and outer rings 11 and 12. The outer ring 12 of the bearing 5 has a spherical raceway surface 12a, and each rolling element 13 has a spherical roller whose outer peripheral surface is along the outer ring raceway surface 12a. The inner ring 11 has a collared structure having the raceway surfaces 11a and 11a in each row individually. The rolling elements 13 are held by a holder 14 for each row. The outer ring 12 is fitted to the inner diameter surface of the bearing housing 15 and the inner ring 11 is fitted to the outer periphery of the rotor shaft 3 to support the rotor shaft 3. In the bearing housing 15, a seal 16 such as a labyrinth seal is formed between the side wall 15 a that covers both ends of the bearing 5 and the main shaft 3. Since the sealing performance is obtained by the bearing housing 15, the bearing 5 has a structure without a seal. In a space formed between the inner ring 11 and the outer ring 12 and in which the rolling elements 13 are disposed, a grease composition containing a predetermined phosphite as an additive to be described later is enclosed.

  Another example of the rolling bearing for wind power generator of the present invention is shown in FIG. FIG. 4 is a cross-sectional view of a deep groove ball bearing. In the deep groove ball bearing 21, an inner ring 22 having an inner ring rolling surface 22a on the outer peripheral surface and an outer ring 23 having an outer ring rolling surface 23a on the inner peripheral surface are arranged concentrically, and the inner ring rolling surface 22a and the outer ring rolling surface 23a. A plurality of rolling elements 24 are disposed between the two. A holder for holding the plurality of rolling elements 24 is provided. In addition, seal members 26 fixed to the outer ring 23 and the like are provided in the axial end openings 28a and 28b of the inner ring 22 and the outer ring 23, respectively. In a space formed between the inner ring 22 and the outer ring 23 and in which the rolling elements 24 are arranged, a grease composition 27 containing a predetermined phosphite as an additive to be described later is enclosed.

  As the rolling bearing for wind power generator of the present invention, in addition to those shown in the above drawings, angular ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, thrust cylindrical roller bearings, thrust tapered roller bearings, thrust needles Roller bearings, thrust spherical roller bearings, and the like can also be used.

  The bearing 5 for supporting the main shaft may be a radial bearing capable of thrust load. In addition to the self-aligning roller bearing shown in the drawings, among the above, angular ball bearings, tapered roller bearings, deep groove ball bearings, etc. It may be. Among these, the main shaft support bearings for wind turbines that are operated in a wide range of loads from light loads to heavy loads in gusts and where wind direction changes constantly occur are Spherical roller bearings that can absorb deflection are particularly preferred. Further, as the blade bearing and the yaw bearing, a deep groove ball bearing and an angular ball bearing are preferable.

  The grease composition to be enclosed in the rolling bearing for wind power generator according to the present invention contains a base oil, a thickener, and an additive, and the additive contains a predetermined phosphite.

（式（１）（２）において、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５は、それぞれメチル基またはエチル基である。また、Ｒ_１とＲ_２とは、Ｒ_３とＲ_４とＲ_５とは、同一の基であっても異なる基であってもよい。） The predetermined phosphite used in the grease composition is at least one phosphite represented by the following formula (1) or (2). The phosphorous acid ester represented by these formulas may be used individually by 1 type, or may mix 2 or more types.

(In Formulas (1) and (2), R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each a methyl group or an ethyl group. R ₁ and R ₂ are R ₃ and R ₄ , respectively. And R ₅ may be the same group or different groups.)

  Phosphites represented by formula (1) or formula (2) are, for example, phosphite diesters such as dimethyl phosphite, diethyl phosphite, methyl ethyl phosphite, trimethyl phosphite, phosphorus phosphite Phosphorous acid triesters such as triethyl acid, dimethyl ethyl phosphite, and methyl diethyl phosphite. Among these, dimethyl phosphite, diethyl phosphite, trimethyl phosphite, or triethyl phosphite is preferable.

  In the grease composition, the content of the phosphite is 0.5 to 4 parts by weight with respect to 100 parts by weight of the total amount of the base oil and the thickener. If the phosphite content is less than 0.5 parts by weight, the fretting resistance may not be improved. Moreover, even if the content of the phosphite exceeds 4 parts by weight, the fretting resistance is hardly improved further. In addition, when using 2 or more types of phosphites, let the total amount be in the said range.

  Moreover, it is preferable that the said grease composition does not contain phosphite other than the phosphite represented by the said Formula (1) or (2). Moreover, it is preferable that the phosphate ester which has a C3 or more organic group is not included. That is, it is preferable not to include anything other than the oxidized phosphorous acid ester represented by the above formula (1) or (2). When these phosphites and phosphates are included, the fretting resistance may be inferior.

  The grease composition uses the predetermined low molecular weight phosphite ester as an additive, and is conventionally blended to prevent fretting and surface-origin peeling, such as zinc dithiophosphate and tricresyl phosphate. Even when other phosphorus compounds and other extreme pressure agents are not blended, the occurrence of fretting can be prevented.

  Moreover, you may make the said grease composition contain well-known additives other than the said phosphite as needed. Such additives include antioxidants such as phenols and amines, rust inhibitors such as carboxylates and sulfonates, antiwear agents such as polyalkylene glycol and glycerin, chlorinated paraffin, sulfurized oil, organic Examples include extreme pressure agents such as molybdenum compounds, oiliness improvers such as higher fatty acids and synthetic esters, and solid lubricants such as graphite and molybdenum disulfide. In addition, these can be added individually or in combination of 2 or more types.

The base oil of the grease composition is a kinematic viscosity of 300~600mm ² / s at 40 ° C., more preferably 350~550mm ² / s, most preferably 400-500 ² / s. The wind turbine generator rotates the main shaft to which the blades are attached by wind power. When the wind power is weak, the main shaft rotates at a very low speed, so the oil film on the bearing that supports the main shaft is relatively thin and unstable. . For this reason, when the kinematic viscosity at 40 ° C. is less than 300 mm ² / s, the oil film may be easily cut. On the other hand, when the kinematic viscosity at 40 ° C. is higher than 600 mm ² / s, the supply of lubricating oil to the rolling surface is poor and fretting tends to occur. Further, since the torque of the bearing is increased, there is a risk that the power generation efficiency is reduced. In addition, when using mixed oil as a base oil, it is preferable that dynamic viscosity of this mixed oil is in the said range.

  The type of base oil of the grease composition is not particularly limited as long as it satisfies the above kinematic viscosity range, and general oils usually used in the field of grease can be used. For example, synthetic oil, mineral oil, or these mixed oils are mentioned. In the present invention, synthetic oil is mainly used.

  Examples of the mineral oil include those obtained by a method usually used in a process for producing a lubricating oil in the oil refining industry, more specifically, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil. Is obtained by performing one or more treatments such as solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment.

  Examples of the synthetic oil include polyα-olefins such as polybutene, 1-octene oligomer, 1-decene oligomer, or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-3- Diesters such as ethylhexyl sebacate; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate; alkylnaphthalenes; alkylbenzenes, polyoxyalkylene glycols; polyphenyl ethers Dialkyl diphenyl ether; silicone oil; fluorine oil; and the like. Other examples include GTL oil synthesized by the Fischer-Tropsch method. Among these, since it is excellent in oxidation stability and low temperature property (because it is often used in a cold place such as a highland), it is preferable to use a poly α-olefin which is a synthetic oil.

  The thickener of the above-mentioned grease composition is not particularly limited, and general ones usually used in the field of grease can be used. For example, soap-type thickeners such as metal soaps and composite metal soaps, and non-soap-type thickeners such as benton, silica gel, urea compounds, urea / urethane compounds, and fluororesins can be used. Examples of the metal soap include sodium soap, calcium soap, aluminum soap and lithium soap. Examples of urea compounds and urea / urethane compounds include diurea compounds, triurea compounds, tetraurea compounds, other polyurea compounds, and diurethane compounds. Among these, lithium soap (including complex lithium soap) and urea compounds are used because they are excellent in heat resistance and durability, adherence to rolling surfaces, and are easy to prevent fretting. preferable.

  A urea compound is obtained by reacting an isocyanate compound and an amine compound. In order not to leave a reactive free radical, the isocyanate group of the isocyanate compound and the amino group of the amine compound are preferably blended so as to be approximately equivalent.

  A diurea compound is obtained by reaction of a diisocyanate and a monoamine, for example. Examples of the diisocyanate include phenylene diisocyanate, tolylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, stearylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine are the same as those used for producing the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, and diaminodiphenylmethane.

  A base grease for blending the above-mentioned additives can be obtained by blending the base oil with a thickener such as composite lithium soap or urea compound. A base grease using a urea compound as a thickener is produced by reacting the diisocyanate with a monoamine in a base oil.

  The content of the thickener in 100 parts by weight of the base grease is preferably 3 to 40 parts by weight, and more preferably 5 to 30 parts by weight. It is suitable for obtaining the inherent lubricity of the grease composition to be within this range. If the content of the thickener is less than 3 parts by weight, the thickening effect is reduced and it becomes difficult to form a grease. When the content of the thickener exceeds 40 parts by weight, the obtained base grease becomes too hard, and it is difficult to obtain the desired effect.

  It is preferable that the penetration degree (JIS K 2220) of the grease composition is in the range of 200 to 350. When the consistency is less than 200, oil separation at a low temperature is small, resulting in poor lubrication and fretting is likely to occur. On the other hand, if the consistency exceeds 350, the grease is soft and easily flows out of the bearing, which is not preferable.

  The present invention will be specifically described with reference to examples and comparative examples, but is not limited to these examples.

Examples 1 to 12 and Comparative Examples 1 to 4
As shown in Tables 1 to 3, a base grease was prepared by selecting a thickener and a base oil. The composition of the base grease is 100 parts by weight in total of the thickener and the base oil. Here, “synthetic oil”, which is a base oil in each table, is a trade name “Mobile Gear SHC XMP460” manufactured by ExxonMobil.

  In addition, a “lithium complex” (composite lithium soap), which is a thickener, is obtained by adding lithium hydroxystearate to the base oil, and at a ratio of 1 mole of lithium hydroxide monohydrate to 1 mole of hydroxystearic acid. Saponified, then added azelaic acid, saponified at a ratio of 1 mole of lithium hydroxide monohydrate to 1 mole of azelaic acid, then heated to 200 ° C., cooled, and then mixed in a three roll mill. I got it.

  “Urea”, a thickener, dissolves MDI (manufactured by Nippon Polyurethane Industry Co., Ltd .: trade name MILLIONATE MT (main component: diphenylmethane diisocyanate)) in half of the base oil, and MDI in the remaining half of the base oil. P-toluidine which is twice the equivalent of was dissolved and mixed with stirring.

  Additives were added in the proportions shown in each table to 100 parts by weight of the base grease prepared above, and sufficiently stirred with a stirring deaerator to obtain a test grease. In Tables 2 and 3, 1) 2) is the same as 1) 2) shown in the lower part of Table 1. About the obtained test grease, it used for the fretting test shown below and measured the abrasion loss. The results are shown in each table.

<Fretting test>
In accordance with ASTM D4170, a performance evaluation test was performed using a Fafner fine movement wear tester. 51204J was used as a bearing, and the test time was 2 hours under the conditions of a maximum contact surface pressure of 1.7 GPa, a rocking cycle of 30 Hz, a rocking angle of 12 °, and an ambient room temperature (25 ° C). Evaluation was based on the amount of wear (mg) per bearing.

  As shown in Comparative Examples 1 and 3, when no additive was added, the anti-fretting performance was poor. In addition, as shown in Comparative Examples 2 and 4, when an additive (TCP) other than the phosphite used in the present invention was added, the result was the same as when no additive was added, and the fretting performance was improved. I could n’t. On the other hand, in each of the comparative examples, excellent fretting resistance could be obtained.

  The rolling bearing for a wind power generator according to the present invention has excellent fretting resistance and can prevent wear on the rolling surface of the bearing while being used in an environment in which repeated swinging due to wind strength and direction is applied. Therefore, it can be suitably used as a bearing for supporting the main shaft, blade, or yaw of the wind power generator.

DESCRIPTION OF SYMBOLS 1 Wind power generator 2 Rotor blade 3 Rotor shaft 4 Nacelle 5 Bearing (rolling bearing)
6 speed increaser 7 generator 8 tower 9 motor 10 speed reducer 11 inner ring 12 outer ring 13 rolling element 14 cage 15 bearing housing 16 seal 17 yaw swivel seat bearing 21 deep groove ball bearing 22 inner ring 23 outer ring 24 rolling element 25 cage 26 seal Member 27 Grease composition 28a, 28b Opening

Claims (6)

A rolling bearing for a wind power generator incorporated in a wind power generator, wherein the bearing has a plurality of rolling elements arranged between an inner ring and an outer ring so as to be freely rotatable, and is formed between the inner ring and the outer ring. And a grease composition containing a base oil, a thickener, and an additive is enclosed in the space in which the rolling elements are disposed,
The base oil is a synthetic oil, and the kinematic viscosity at 40 ° C. is 300 to 600 mm ² / s,
The additive contains at least one phosphite ester represented by formula (1) or (2), and the content of the phosphite ester is a total amount of the base oil and the thickener of 100. Ri 0.5 to 4 parts by weight of der against parts by weight,
The grease composition does not contain a phosphite other than the one represented by the formula (1) or (2) and a phosphate ester having an organic group having 3 or more carbon atoms. Rolling bearing for use.

(In Formulas (1) and (2), R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each a methyl group or an ethyl group. R ₁ and R ₂ are R ₃ and R ₄ , respectively. And R ₅ may be the same group or different groups.)   The rolling bearing for wind power generator according to claim 1, wherein the phosphite is dimethyl phosphite, diethyl phosphite, trimethyl phosphite, or triethyl phosphite. The rolling bearing for wind power generator according to claim 1 or 2 , wherein the thickener is at least one selected from lithium soap and a urea compound. The rolling bearing for a wind power generator according to any one of claims 1 to 3 , wherein the grease composition has a penetration degree of 200 to 350. The rolling bearing for wind power generator according to any one of claims 1 to 4 , wherein the rolling bearing for wind power generator is a deep groove ball bearing, a roller bearing, or an angular ball bearing. The rolling bearing for wind power generator according to any one of claims 1 to 5 , wherein the rolling bearing for wind power generator is a bearing that supports a main shaft, a blade, or a yaw of the wind power generator. .

Images