JP2015227651A - Wind power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind power generator which both prevents a connection face between a hub and a rotary main shaft from sliding due to the addition of a torque by the rotation of a windmill, and keeps the hub in a small construction.SOLUTION: A wind power generator includes a blade 2 which receives wind and rotates, a hub 1 supporting the blade, and a rotary main shaft 6 which rotates in conjunction with the rotation of the hub. The hub 1 and the rotary main shaft 6 are connected via a high friction part.

Description

    The present invention relates to a wind turbine generator, and more particularly to a rotor support structure for a wind turbine generator.

    Wind power generation, which is attracting attention as a renewable energy source, has recently been introduced rapidly and its power generation capacity has increased. Horizontal axis wind turbines are the most popular type of large-capacity wind power generators, and rotate by transmitting the rotation of the rotor located on the side of the nacelle at the top of the tower to the generator inside the nacelle. Energy is converted into electrical energy. Large horizontal axis wind turbines have a power generation capacity of more than 5MW, and the blade diameter may exceed 100m.

    With the increase in size of wind power generators, the transmission torque that is handled by the power transmission mechanism that transmits the rotation of the rotor to the generator has become extremely large. With increasing torque, the connection between wind turbine components that transmit it must be made stronger. In particular, it is necessary to prevent the torque at the location where the component parts are connected to each other by a flange-like surface perpendicular to the rotation axis, because the torque is applied in the direction in which the fastening surface slips. Such a connection location includes, for example, a bolt fastening portion between a hub located near the center of rotor rotation and a rotation main shaft. In Patent Document 1, the spherical shell-shaped hub has a main shaft connecting portion on the nacelle side, the main shaft has a flange on the hub side, and the main shaft connecting portion and the flange are fixedly connected by bolts.

    On the other hand, the weight of the upper part of the tower of the wind power generator greatly affects the strength that the tower should satisfy, so it is desirable to keep it as small as possible. In particular, in the case of a horizontal axis wind turbine, it is important to reduce the rotor weight. This is because an unstable structure in which the rotor weight is cantilevered by the shaft extending from the nacelle must be supported at the upper part of the tower of the horizontal axis wind turbine. This is because it becomes difficult. Further, by reducing the weight, it is possible to reduce the transportation cost and the cost of performing a highly difficult construction work of installing a heavy object at a high place.

JP 2008-128135 A

  In the connection portion between the hub of the wind turbine generator and the rotation main shaft, the hub disposed at the center of the rotor rotation is downsized to reduce the rotor weight and provide a highly reliable connection structure for torque load. It is desirable.

  As a means for preventing slipping of the connecting portion, for example, a method of increasing the number of bolts and increasing the surface pressure of the connecting surface can be considered, but when considering reducing the size of the hub at the same time, the connection between the hub and the rotating spindle is possible. The area of the part is reduced, and the number of bolts that can be increased is limited. Moreover, the increase in the number of bolts itself increases the weight of the hub. Thus, it can be said that there is a trade-off between the reliability of the connection between the hub and the rotating spindle and the miniaturization of the hub.

  The problem to be solved by the present invention is to provide a wind turbine generator that can improve both the reliability of the connection surface of the hub and the rotating spindle and keep the hub small with respect to the torque load caused by the windmill rotation. It is to be.

  In order to solve the above-described problems, a wind power generator according to the present invention includes a blade that rotates by receiving wind, a hub that supports the blade, and a rotation main shaft that rotates as the hub rotates. The hub and the rotating main shaft are connected via a high friction part.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the wind power generator which improves the reliability of the connection surface of a hub and a rotation main shaft with respect to the torque load by windmill rotation, and keeps a hub small. become.

The figure which showed the structure of the general horizontal axis windmill. The figure which showed the structure inside a hub and a nacelle. The figure which showed the rotor support structure of an outer ring drive. The figure which looked at the bolt fastening part of the hub and the rotation main shaft from the axial direction of the rotation main shaft. The figure which showed the cross section for one volt | bolt among the fastening parts shown in FIG. The figure which showed the example of the rotor support structure in the case of assembling by inserting a rotation main shaft from the nacelle side. The figure which showed the divided | segmented high friction member.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated with reference to drawings. The following description is one example of the present invention and does not limit the present invention.

    In addition, in order to constitute the friction part described below, a high friction material is sprayed on the surface of at least one of the hub and the rotation main shaft, or a high friction paint is applied between the hub and the rotation main shaft. And the like.

  When a high friction member is inserted, the high friction member is preferably formed in an annular shape in accordance with the shape of the connection surface between the hub and the rotation main shaft. Furthermore, it is also possible to divide the annular high friction member into a plurality of parts in the circumferential direction.

  In some cases, in the wind turbine generator, the fixed main shaft fixed to the nacelle is disposed on the inner peripheral side of the hub, a bearing is provided between the hub and the fixed main shaft, and the rotating main shaft is disposed on the inner peripheral side of the fixed main shaft. It is also possible to have a structure called outer ring drive. Further, the rotation main shaft is a diameter-expanded portion whose tip opposite to the nacelle expands in the radial direction, and the diameter-expanded portion may be connected to the hub. At this time, the hub has a flange protruding on the inner diameter side, and is connected to the rotation main shaft at the flange, and may have an opening for inserting the rotation main shaft on the side opposite to the nacelle. In order to allow the main shaft to be inserted, the maximum radial width of the enlarged diameter portion of the rotating main shaft needs to be smaller than the opening. Hereinafter, detailed embodiments will be described with reference to the drawings.

  Figure 1 shows an overview of a typical horizontal axis wind power generator. The horizontal axis wind power generator has a blade 2 whose root is supported by a hub 1. A rotating body composed of a blade and a hub is called a rotor 3, and the rotor rotates around the hub when the blade receives wind. The rotor is supported by the nacelle 4, and the nacelle is arranged at the upper part of the tower 5 standing in a substantially vertical direction with respect to the ground.

  FIG. 2 shows the internal configuration of the hub and nacelle. The hub is connected to the rotation main shaft 6, and the rotation main shaft transmits the rotation of the rotor to the gearbox input shaft 7 inside the nacelle. The speed increaser 8 converts the low speed rotation of the rotating main shaft into a high speed rotation. The speed increaser output shaft 9 that rotates at high speed is connected to the generator shaft 10, and the generator 11 converts the rotational energy transmitted from the rotor by the above power transmission mechanism into electrical energy.

  FIG. 3 shows a structure in which the nacelle supports the rotor by the outer ring drive system. In the outer ring drive system, a hollow fixed main shaft 12 disposed on the inner peripheral side of the hub is fixed to the side surface of the nacelle, the hub is positioned on the outer peripheral side of the fixed main shaft, and a bearing 13 is provided between the fixed main shaft and the hub. The rotating main shaft that is disposed and located on the inner peripheral side of the fixed main shaft is connected to the hub. Here, the fixed main shaft is relatively stationary with respect to the nacelle, while the rotating main shaft is connected to the hub and thus rotates with the rotation of the rotor.

  In the outer ring drive system, the fixed main shaft mainly shares the function of supporting the rotor weight on the nacelle, and the rotating main shaft shares the function of transmitting the rotation of the rotor to the gearbox. In contrast, when a single shaft has both weight support and rotational transmission, the shaft is subjected to severe load conditions in which extreme weight is loaded at the end and the load is fluctuated by wind. And you have to rotate while keeping the axis. As a result, measures such as increasing the shaft diameter and using a highly rigid material are required to increase the strength of the shaft, and the weight of the shaft increases. On the other hand, the outer ring drive type rotation main shaft is light in weight due to the weight of the rotor, so it can be light and low in rigidity, and the rotor support structure as a whole can be lightened.

  In FIG. 3, the rotation main shaft has an end portion (expanded diameter portion) which is called a bell mouth 14 and expands in the radial direction. Here, the radial direction refers to a direction substantially perpendicular to the axial direction of the rotation main shaft. Bellmouth is highly flexible and has the effect of absorbing misalignment in the axial direction and radial direction of the main shaft. On the other hand, the hub has a flange 15 projecting toward the inner diameter side. The flange is positioned on the nacelle side of the bell mouth and is bolted to the bell mouth.

  When assembling the wind turbine generator in the present embodiment, the rotation main shaft is inserted into the hub through the opening 16 provided on the opposite side of the hub from the nacelle. An arrow 17 shown in FIG. 3 indicates the insertion direction of the rotating spindle. Here, if the maximum radial width of the bell mouth is defined as a and the minimum radial width of the nacelle opening is defined as A, a <A must be satisfied in order to allow insertion of the rotation spindle. The radial minimum width A of the hub opening has a great influence on the overall size of the hub, and is desirably as small as possible in view of weight reduction. When A becomes smaller, the maximum width a in the radial direction of the bell mouth must be made smaller than that, but the rotation main shaft is bolted to the flange of the hub at the outer periphery of the bell mouth, so the fastening area is reduced.

  FIG. 4 shows a bolt fastening portion between the bell mouth and the flange as viewed from the axial direction of the rotating main shaft. The bell mouth or flange is fastened by a bolt 18 at its outer periphery. An arrow 19 represents the direction of torque applied to the bolt fastening portion by the rotation of the rotor, and this torque is applied in a direction that causes slipping on the fastening surface between the bell mouth and the flange.

  FIG. 5 is a cross-sectional view of a fastening portion for one bolt in FIG. If F is the external force applied in the direction in which slip occurs due to torque, N is the force applied to all the bolts by the fastening surface, and μ is the maximum coefficient of static friction of the fastening surface 20, it will be applied to the fastening surface when F> μN. Slip occurs. As described above, if the maximum width a in the radial direction of the bell mouth is reduced in order to reduce the size of the hub, the fastening area is reduced and the number of bolts that can be used is reduced. The decrease in the number of bolts means that N becomes smaller, and therefore the allowable external force F for preventing slipping becomes smaller. Here, as a method for reducing the minimum radial width A of the hub opening and increasing the allowable external force F, it is preferable to increase the maximum static friction coefficient μ of the fastening surface.

  In the wind turbine generator according to the present invention, the bell mouth of the rotating spindle and the flange of the hub are connected via a high friction part. High friction means that a larger friction coefficient can be given than when the rotating spindle and the hub are directly connected, and that the maximum static friction coefficient between general steel materials is 0.1 to 0.2. In consideration, the effect can be expected if it is at least larger than the maximum static friction coefficient 0.2. As a means for imparting high friction, a member having a high coefficient of friction may be inserted into the connection surface, or a material having a high coefficient of friction may be sprayed on at least one of the surfaces of the rotating main shaft and the hub.

  In the embodiment, as a means for imparting a high friction coefficient, an annular high friction member is sandwiched between the flange of the hub and the bell mouth of the rotating main shaft. As the high friction member, for example, a metal base material surface sprayed with tungsten particles may be used. In the above assembly procedure, the high friction member is inserted immediately after the hub to which the fixed main shaft is attached is turned upside down so that the nacelle side is down, and immediately before the rotation main shaft is inserted into the hub. The member is placed on a flange protruding inside the hub, and a bell mouth of a rotating spindle to be inserted thereafter is placed on the high friction member and finally bolted.

  A second mode for carrying out the present invention will be described with reference to FIG. Note that the description of the same structure as that of the first embodiment is omitted.

  In the first embodiment, the rotation main shaft is inserted from the opening provided on the opposite side of the hub from the nacelle. In this embodiment, the rotation main shaft is inserted from the nacelle side to the inside of the fixed main shaft in the hub. An arrow 22 indicates the insertion direction of the rotation main shaft. The inserted bell mouth of the rotating spindle is positioned closer to the nacelle side than the flange or wall surface protruding to the inner peripheral side of the hub, and the outer peripheral portion is bolted to the flange or wall surface. Here, if the radial minimum width of the fixed main shaft is defined as B, a <B must be satisfied in order to allow the rotation main shaft to be inserted. By comprising in this way, after attaching a rotation main axis | shaft to a nacelle, other rotor parts, such as a hub and a fixed main axis | shaft, can be installed in a nacelle. In a large-scale wind power generator, the weight of the rotor is very large, and it is not easy to install it by lifting it on the top of the tower. In the embodiment, only the rotating main shaft is attached to the nacelle first, and the rotor to be lifted later can be reduced in weight without including the rotating main shaft, so that the construction period is shortened and the cost is reduced.

  The third embodiment has a structure in which the annular high-friction member sandwiched between the flange of the hub and the bell mouth of the rotating main shaft in the first or second embodiment is divided into a plurality in the circumferential direction. FIG. 7 shows the divided high friction member 23. When a high friction member is inserted as a means for imparting high friction, the high friction member can be prevented from hitting the hub or the rotating main shaft by dividing the high friction member in the circumferential direction. Moreover, when producing a high friction member, it can process with high plane accuracy. The divided high friction member also has an advantage that it can be easily removed during maintenance of the wind turbine generator.

  By dividing, there is an effect of reducing the contact between the high friction member and the flange or between the high friction member and the bell mouth. In particular, in the case of a large-scale wind power generator, it is difficult to obtain a flat surface accuracy of the flange surface, and a single contact is likely to occur, but the high friction member easily follows the flange surface by the division. Further, the production of the high friction member becomes easy, and the planar processing accuracy can be improved. Furthermore, when divided in this way, the fastening portion can be easily disassembled when maintenance or parts replacement is required. Without splitting, the high-friction member cannot be removed unless the rotating spindle is pulled out of the hub after removing the bolts. However, when splitting, only the high-friction member is removed without moving the rotating spindle out of the hub. be able to.

    As described in the above embodiments, the connection area between the hub and the rotating spindle is a high friction part, so that the area of the connecting surface is limited by the limitation that the radial maximum width of the rotating spindle must be smaller than the hub opening. Even if it is unavoidable to make the connection smaller, it is possible to achieve a connection in which slippage is unlikely to occur, and it is possible to achieve both the miniaturization of the hub and the strength of the connection. Moreover, damage to connecting members such as bolts and nuts can be prevented. In addition, since the number of members such as bolts and nuts that apply a substantially vertical force to the connection surface can be reduced, an effect of reducing the weight of the rotor can be expected.

DESCRIPTION OF SYMBOLS 1 Hub 2 Blade 3 Rotor 4 Nacelle 5 Tower 6 Rotation main shaft 7 Speed increaser input shaft 8 Speed increaser 9 Speed increaser output shaft 10 Generator input shaft 11 Generator 12 Fixed main shaft 13 Bearing 14 Bell mouth 15 Flange 16 Opening 17 Rotating Spindle Insertion Direction 18 Bolt 19 Torque Direction 20 Fastening Surface 21 of Hub and Rotating Spindle Nut 22 Rotating Spindle Insertion Direction of Embodiment 2

Claims (8)

A blade that rotates in response to the wind;
A hub that supports the blade;
A rotation spindle that rotates as the hub rotates,
The hub and the rotating main shaft are connected via a high friction part.   2. The wind power generator according to claim 1, wherein a high friction portion is formed on a surface of at least one of the hub and the rotation main shaft. 3.   The wind power generator according to claim 1, wherein a high friction member is disposed between the hub or the rotating main shaft.   The wind power generator according to claim 3, wherein the high friction member is divided into a plurality in the circumferential direction.   The wind turbine generator according to any one of claims 1 to 4, further comprising a fixed main shaft disposed on an inner peripheral side of the hub, and a bearing provided between the fixed main shaft and the hub. Wind power generator characterized by that.   6. The wind turbine generator according to claim 5, wherein a tip end of the rotation main shaft is a radially enlarged portion that expands in a radial direction, and the radially enlarged portion is connected to the hub. The wind turbine generator according to claim 6,
Furthermore, a nacelle having a device to which the rotational energy of the rotating spindle is transmitted,
A flange that protrudes on the inner diameter side of the hub and is provided on the nacelle side with respect to the enlarged diameter portion and connected to the enlarged diameter portion,
An opening formed on the opposite side of the hub from the nacelle,
The wind power generator characterized by the said opening part being larger than the radial direction maximum width of the said enlarged diameter part. The wind turbine generator according to claim 6,
Furthermore, a nacelle having a device to which the rotational energy of the rotating spindle is transmitted,
A flange that protrudes on the inner diameter side of the hub and is provided on the opposite side to the nacelle with respect to the enlarged diameter portion and connected to the enlarged diameter portion,
An opening formed on the nacelle side of the hub,
The wind power generator characterized by the said opening part being larger than the radial direction maximum width of the said enlarged diameter part.