JP2008286136A - Yaw bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a yaw bearing having high weather resistance for turnably supporting a nacelle of a wind power generator. <P>SOLUTION: The yaw bearing 11 is provided for turnably supporting the nacelle 34 of the wind power generator 31. It comprises an annular-shape horizontal sliding plate 12 for abutting on the lower face of the nacelle 34 to support the thrust load. The horizontal sliding plate 12 is a fluororesin molded product. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a yaw bearing that rotatably supports a nacelle of a wind power generator.

  A yaw bearing that rotatably supports a nacelle of a conventional wind power generator is described in, for example, Japanese Patent Laid-Open No. 8-82277 (Patent Document 1). The yaw bearing described in the publication uses a rolling bearing. A braking brake is provided to stably hold the nacelle against the wind direction.

  Since a rolling bearing which is a conventional yaw bearing has a small rotational resistance, a braking brake having a strong braking force is required to prevent the nacelle from exceeding the stop position due to an inertial force. As a result, there are problems such as increasing the size of braking brakes, installing a large number of brakes, increasing the size and complexity of the device, increasing the weight, and increasing the price. In addition, rolling bearings require maintenance with grease replenishment, and contamination with grease has also been a problem.

Therefore, a wind power generator that solves the above problem is described in, for example, US Patent Publication No. 2005-196280 (Patent Document 2). The wind power generator described in the publication employs a sliding bearing composed of a plurality of sliding plates as a yaw bearing. As a result, it is described that the braking brake is simplified and the apparatus can be reduced in size and price. Further, it is described that the sliding plate is made of polyethylene terephthalate (PET).
JP-A-8-82277 US Published Patent No. 2005-196280

  Wind generators are often installed around the coast as a stable geography of wind direction and wind, and are required to have high weather resistance because they continue to be exposed to coastal sea breezes. Also, the wind power generator has a tower that supports the nacelle with a total length of 30 m or more, and is difficult to maintain. Further, the yaw bearing arranged in the nacelle may reach 60 ° C. under the summer sun, and it is necessary that the friction characteristics with respect to the heat change do not vary.

  However, polyethylene terephthalate may be reduced in friction characteristics and mechanical strength due to hydrolysis, and it is considered that the sliding plate needs to be periodically replaced in order to prevent problems with the wind power generator.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a yaw bearing having a high weather resistance and a long service life, which is a bearing that supports a nacelle of a wind power generator in a swingable manner.

  A yaw bearing according to the present invention is a bearing that rotatably supports a nacelle of a wind power generator, and includes an annular horizontal sliding plate that abuts the lower surface of the nacelle and supports a thrust load. The horizontal sliding plate is a fluororesin molded body. For this reason, even if it is installed on the coast, there is no hydrolysis and corrosion by salt water, and the frictional characteristics and mechanical strength are stable over the long term. As a result, maintenance-free for 30 years or more can be achieved.

  Preferably, the fluororesin molded body contains polytetrafluoroethylene as a base material. Polytetrafluoroethylene is suitable as a material for the horizontal sliding plate because it is low in price, excellent in availability, and easy to control the friction characteristics.

  Preferably, the fluororesin molded body includes a friction adjusting material. And the area ratio of the friction adjustment material exposed to the wall surface of the horizontal sliding plate contact | abutted to a nacelle is 5%-40%. By adding the above additive, the friction stability of the fluororesin molded body is improved. As a result, the braking brake can be reduced in size or labor saving.

  Preferably, the fluororesin molded body includes a non-corrosive compounding material that suppresses corrosion of the base material. As a result, high friction characteristics and mechanical strength can be maintained over a long period of time even when the wind power generator is installed around the coast.

  Preferably, the fluororesin molded body includes a reinforcing material. As a result, the wear resistance can be improved and the creep due to the load can be effectively prevented.

  Preferably, the fluororesin molded body is made of glass fiber, carbon fiber, graphite, silicon carbide, potassium titanate, magnesium borate, zinc oxide, titanium oxide, calcium sulfate, magnesium sulfate, iron oxide, alumina, and wollastonite. At least one additive selected from the group consisting of:

  Preferably, the horizontal sliding plate is formed by connecting a plurality of arc-shaped sliding members in the circumferential direction. Since the yaw bearing is very large, the above configuration improves the assembly of the yaw bearing and facilitates maintenance.

  Preferably, the yaw bearing is a cylindrical member extending in a direction intersecting with the horizontal sliding plate from the inner peripheral surface of the horizontal sliding plate, and further includes a vertical sliding plate that supports a radial load applied to the nacelle. Prepare. The vertical sliding plate is a fluororesin molded body.

  According to this invention, since the sliding plate of the yaw bearing is formed of the fluororesin, it is possible to effectively prevent hydrolysis and corrosion due to salt water even when installed on the coast. As a result, a yaw bearing having high weather resistance and a long life can be obtained.

  With reference to FIG. 3 and FIG. 4, the wind power generator 31 which employ | adopted the yaw bearing 11 (it is also mentioned a "swivel seat bearing") which concerns on one Embodiment of this invention is demonstrated. The wind power generator 31 includes a support base 32, a yaw bearing 11, a nacelle 34, a blade 35, a main shaft 36, a speed increaser 37, a generator 38, a bearing housing 39, and a main shaft support bearing 42. The motor 40 for rotation and the reduction gear 41 are provided.

  The nacelle 34 is installed on the support base 32 via the yaw bearing 11, and can be turned horizontally by a turning motor 40 and a speed reducer 41. Moreover, it functions as a housing that accommodates the main shaft 36, the speed increaser 37, the power generator 38, the main shaft support bearing 42, the turning motor 40, the speed reducer 41, and the like, which are the main components of the wind power generator 31.

  The blade 35 is fixed to one end of the main shaft 36 and rotates by receiving wind. One end of the main shaft 36 is connected to the blade 35 and the other end is connected to the speed increaser 37, and the rotation of the blade 35 is transmitted to the generator 38 via the speed increaser 37. Further, it is rotatably supported by a spindle support bearing 42 incorporated in the bearing housing 39.

  Next, with reference to FIG. 1 and FIG. 2, the yaw bearing 11 of the wind power generator 31 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a view showing a yaw bearing 11 according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the yaw bearing 11.

  First, referring to FIG. 1, the yaw bearing 11 includes a horizontal sliding plate 12 and a vertical sliding plate 13. The horizontal sliding plate 12 is an annular member, and constitutes a wall surface on one side in the thickness direction of the yaw bearing 11. Specifically, the horizontal sliding plate 12 is formed by connecting a plurality of arc-shaped horizontal sliding members 12a in the circumferential direction. The horizontal sliding plate 12 is a thrust sliding bearing that contacts the lower surface of the nacelle 34 of the wind power generator 31 and supports the thrust load.

  The vertical sliding plate 13 is an arc-shaped member extending from the inner peripheral surface of the horizontal sliding plate 12 in a direction intersecting with the horizontal sliding plate 12 (“orthogonal” in this embodiment). Specifically, the vertical sliding plate 13 is formed by connecting a plurality of arc-shaped vertical sliding members 13a in the circumferential direction. The vertical sliding plate 13 is a radial sliding bearing that supports a radial load applied to the nacelle 34 of the wind power generator 31.

  In this embodiment, the horizontal sliding plate 12 is configured by connecting 12 horizontal sliding members 12a in the circumferential direction. However, the present invention is not limited to this, and an arbitrary number of horizontal sliding members are provided. The horizontal sliding plate 12 can be configured by the member 12a. For example, the number may be about 4 to 16. The same applies to the case where the vertical sliding plate 13 is constituted by the vertical sliding plate member 13a.

  Referring to FIG. 2, horizontal sliding member 12a and vertical sliding member 13a (hereinafter collectively referred to as “sliding member”) are held by arc-shaped attachment portions 21, respectively. And the attaching part 21 which adjoins by a connection means (illustration omitted) is connected to the circumferential direction, and the toroidal yaw bearing 11 as shown in FIG. 1 is comprised.

  The horizontal sliding plate 12 and the vertical sliding plate 13 (hereinafter collectively referred to as “sliding plate”) are fluororesin molded bodies. This fluororesin molded body is a fluororesin composition in which an additive is mixed with a fluororesin as a base material.

  A well-known thing can be used as a fluororesin used as a base material. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE) , Tetrafluoroethylene-fluoroalkyl vinyl ether-fluoroolefin copolymer (EPE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) can be used. Among the fluororesins, polytetrafluoroethylene (PTFE) is preferable because it is inexpensive and excellent in availability and easy to control the friction characteristics.

  The polytetrafluoroethylene (PTFE) that can be used in the present invention includes a tetrafluoroethylene unit, a tetrafluoroethylene unit, and a substituted tetrafluoroethylene unit in which the fluorine of the tetrafluoroethylene is substituted with another organic group The latter is called modified polytetrafluoroethylene. The organic group of the modified polytetrafluoroethylene is not particularly limited, but is preferably a perfluoroalkyl ether group or a fluoroalkyl group.

Such a modified polytetrafluoroethylene has a high melt viscosity of 1 × 10 ⁹ poise or higher at 370 ° C., is characterized by non-melt moldability, and has a melt moldability. It is a resin different from the fluoroalkyl vinyl ether copolymer. The use of modified polytetrafluoroethylene having a modified structure in the molecular chain such as the perfluoroalkyl ether group or the fluoroalkyl group is preferable because creep resistance is improved.

  Commercially available products of polytetrafluoroethylene and modified polytetrafluoroethylene include Teflon (registered trademark) 7J, TG70J manufactured by Mitsui DuPont Fluorochemical Co., Aflon G163 manufactured by Asahi Glass Co., polyflon M111 manufactured by Daikin Industries, Ltd., polyflon M112, Examples include Hostaflon TFM1600 manufactured by Hoechst.

  It is desirable to add a reinforcing material to the fluororesin in order to improve the wear resistance of the sliding plate and prevent creep due to a load. The fluororesin containing the reinforcing material is called “reinforced fluororesin”.

  In addition, the yaw bearing 11 is capable of smoothly turning the nacelle 34 and requires a frictional force so that the inertial force does not exceed the stop position when the braking brake is operated. For this reason, in order to give sufficient frictional force to a fluororesin molded object, it is desirable to add a friction modifier to said fluororesin.

  Furthermore, even when the wind power generator 31 is installed around the coast, a non-corrosive compound that suppresses the corrosion of the base material in order to prevent the frictional characteristics and mechanical strength of the sliding plate from deteriorating over a long period of time. It is desirable to add.

  Examples of the additive having the above properties include glass fibers, carbon fibers, graphite, silicon carbide, potassium titanate, magnesium borate, zinc oxide, titanium oxide, calcium sulfate, magnesium sulfate, and various whiskers and various powders. Examples thereof include iron oxide powder, alumina powder, and wollastonite.

  Next, a method for manufacturing the yaw bearing 11 will be described.

  First, a fluororesin composition in which an additive is added to a fluororesin as a base material is prepared. Next, the fluororesin composition is compression molded in a mold to produce a preform. Next, the preform is fired in an electric furnace to produce a sintered body. Further, the sliding member is manufactured by performing necessary machining on the sintered body. Finally, the yaw bearing 11 is assembled with the sliding member and the attachment portion 21.

  As a specific example of the machining, for example, a slide member having a predetermined shape may be obtained by cutting a film that has been skived into a film having a thickness of 1 mm to 2 mm. Note that the sliding member obtained by this method is bonded and fixed to the attachment portion 21.

  As another method, a slide member having a predetermined shape may be obtained by cutting a disk having a thickness of 10 mm to 15 mm. Note that the sliding member obtained by this method is fixed to the attachment portion 21 by bolting means or the like through the bolt hole 22.

  Furthermore, it is desirable to grind the wall surface that contacts the nacelle 34 of the sliding member obtained by any of the above methods. Thereby, if the area ratio of the friction modifier exposed on the processed surface is 5% to 40%, an appropriate frictional force can be applied to the sliding member. As a result, when a braking brake (not shown) that stops turning of the nacelle 34 is operated, the nacelle 34 does not exceed the stop position due to inertial force. If the area ratio of the friction modifier on the sliding surface is less than 5%, the friction coefficient becomes too small and a high braking force is required, and if the area ratio exceeds 40%, the sliding resistance becomes high. Rotation is difficult.

  Note that the fluororesin molded bodies constituting the horizontal sliding plate 12 and the vertical sliding plate 13 may have the same composition or different compositions. For example, a higher effect can be expected if the base material and the additive are appropriately combined according to the characteristics of the load applied to the horizontal sliding plate 12 and the vertical sliding plate 13.

  In the above embodiment, an example in which both the horizontal sliding plate 12 and the vertical sliding plate 13 are made of a fluororesin molded body has been shown. However, only the horizontal sliding plate 12 is made of the above fluororesin composite. Then, the effect of the present invention can be obtained. For example, instead of the vertical sliding plate 13, a radial rolling bearing may be employed.

  Next, a salt spray test and a tensile strength test conducted to confirm the effect of the present invention will be described.

  In each test, three types of test pieces (Examples 1 and 2 and Comparative Example 1) formed into a 5A-type dumbbell shape defined in JIS K7162 (Japan Industrial Standards) were used. Example 1 is a fluororesin molded body using PTFE as a base material and 13 volume% carbon fiber and 5 volume% calcium sulfate powder as additives. Example 2 is a fluororesin molded body using PTFE as a base material and 15% by volume of glass fiber as an additive. Comparative example 1 is PET which is a material of a conventional sliding member.

  First, in order to evaluate the corrosion resistance of a sliding plate, the salt spray test prescribed | regulated to JISZ2371 was implemented. Specifically, 5% saline solution controlled at 35 ° C. was sprayed on the test piece for 2000 hours, and the discoloration of the surface was confirmed visually and with a microscope (× 100).

  As a result, in Examples 1 and 2, no discoloration was observed by visual observation and microscopic observation. On the other hand, it was confirmed that Comparative Example 1 was slightly cloudy visually. Thereby, it was confirmed that the sliding plate which concerns on this invention has high corrosion resistance compared with the conventional sliding plate.

  Next, in order to confirm the change in mechanical strength before and after the salt spray test of the sliding plate, that is, the weather resistance of the sliding plate, a tensile strength test defined in JIS K7162 was performed.

Specifically, the tensile strength F ₁ (Pa) before the salt spray test and the tensile strength F ₂ (Pa) after the salt spray test of each test piece (Examples 1, 2 and Comparative Example 1) were measured. The strength reduction rate (F ₁ −F ₂ ) / F ₁ was calculated. For the sake of accuracy, each test piece was measured three times, and the average value was taken as the test result.

  As a result, the strength reduction rates of Examples 1 and 2 were all 1% to 3%. On the other hand, the strength reduction rate of Comparative Example 1 was 9% to 12%. Thereby, it was confirmed that the sliding plate which concerns on this invention has high weather resistance compared with the conventional sliding plate.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used in a yaw bearing that rotatably supports a nacelle of a wind power generator.

It is a figure which shows the yaw bearing which concerns on one Embodiment of this invention. It is the elements on larger scale of the yaw bearing shown in FIG. It is a figure which shows the wind power generator which employ | adopted the yaw bearing which concerns on one Embodiment of this invention. FIG. 4 is a schematic side view of the wind power generator shown in FIG. 3.

Explanation of symbols

11 Yaw Bearing, 12 Horizontal Sliding Plate, 12a Horizontal Sliding Member, 13 Vertical Sliding Plate, 13a Vertical Sliding Member, 21 Mounting Portion, 22 Bolt Hole, 31 Wind Power Generator, 32 Supporting Base, 34 Nacelle, 35 Blade , 36 spindle, 37 speed increaser, 38 generator, 39 bearing housing, 40 swing motor, 41 speed reducer, 42 spindle support bearing.

Claims (8)

A yaw bearing that rotatably supports a nacelle of a wind power generator,
It has an annular horizontal sliding plate that contacts the lower surface of the nacelle and supports the thrust load,
The horizontal sliding plate is a yaw bearing, which is a fluororesin molded body.   The yaw bearing according to claim 1, wherein the fluororesin molding includes polytetrafluoroethylene as a base material. The fluororesin molded body includes a friction modifier,
The yaw bearing according to claim 1 or 2, wherein the area ratio of the friction modifier exposed on the wall surface of the horizontal sliding plate in contact with the nacelle is 5% to 40%.   The yaw bearing according to any one of claims 1 to 3, wherein the fluororesin molded body includes a non-corrosive compounding material that suppresses corrosion of a base material.   The yaw bearing according to any one of claims 1 to 4, wherein the fluororesin molded body includes a reinforcing material.   The fluororesin molding is a group consisting of glass fiber, carbon fiber, graphite, silicon carbide, potassium titanate, magnesium borate, zinc oxide, titanium oxide, calcium sulfate, magnesium sulfate, iron oxide, alumina, and wollastonite. The yaw bearing according to any one of claims 1 to 5, comprising at least one kind of additive selected from the above.   The yaw bearing according to any one of claims 1 to 6, wherein the horizontal sliding plate is formed by connecting a plurality of arc-shaped sliding members in a circumferential direction. The yaw bearing is a cylindrical member extending in a direction intersecting with the horizontal sliding plate from an inner peripheral surface of the horizontal sliding plate, and further includes a vertical sliding plate that supports a radial load applied to the nacelle. Prepared,
The yaw bearing according to any one of claims 1 to 7, wherein the vertical sliding plate is a fluororesin molded body.

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