Output bearing preload-maintenance device for wind power generator

Abstract

The present invention presents a device for maintaining the preload of a bearing that supports the rotation of an output shaft of a wind power generator. The preload-maintenance device according to the present invention comprises: a wind power generator output shaft of which the outer periphery is partially threaded; a lower nut which is screw-coupled to the output shaft so as to be movable in the vertical direction by means of the rotation thereof, and which can set a preload while the bottom surface thereof is in contact with a bearing; and an upper nut which is screw-coupled to the output shaft so as to be movable in the vertical direction by means of the rotation thereof, and which is in close contact with the upper surface of the lower nut so as to prevent the loosening of the lower nut. In addition, a fastening bolt is screw-coupled to a fastening hole formed in each of the upper nut and the lower nut, and simultaneously fastens the upper nut and the lower nut so as to support that the lower nut does not become loose.

Description

Wind turbine output bearing preload maintenance device

[0001] The present invention relates to an output bearing preload maintenance device for a wind turbine, and more particularly, to an output bearing preload maintenance device for a wind turbine configured to have a simple structure and easy maintenance so as to prevent damage to parts as much as possible.

[0002] The output shaft of a wind turbine is rotatably supported by a number of bearings within the housing. It is widely known that the aforementioned bearings (output bearings) can support the efficient rotation of the output shaft when the preload is appropriately adjusted. Figure 1 illustrates an example device for setting and maintaining the preload of a bearing using a DCN-type lock nut.

[0003] The output shaft (2) is supported by a number of bearings (4, 8) inside the housing (6). A DCN type lock nut (9) is screw-connected to the output shaft (2) and is in contact with the upper side of the inner ring of the bearing (4). Here, the preload generated when the lock nut (9) comes into contact with the inner ring of the bearing (4) is determined depending on the position of the lock nut (9).

[0004] In this DCN type lock nut (9), a headless bolt is combined and used in the central part of the lock nut (9) which is composed of a single body, but there is a disadvantage that damage due to external force can easily occur in this part. In addition, another type of lock nut, AN type, is also used, but this is evaluated to have a disadvantage that damage to the assembled part among the two parts that are assembled together is frequent.

[0005] The main purpose of the present invention is to provide an output bearing preload maintenance device for a wind turbine, which can simplify the processing process and is economically advantageous by not requiring processing of a complex structure.

[0006] Another object of the present invention is to provide an output bearing preload maintenance device for a wind turbine in which the set preload is not arbitrarily released and can be maintained for a long period of time.

[0007] The wind turbine output bearing preload maintaining device of the present invention comprises: an output shaft of the wind turbine having a portion of an outer periphery threaded; a lower nut screw-connected to the output shaft and capable of moving up and down by rotation, the lower surface of which is in contact with the bearing and capable of setting a preload; and an upper nut screw-connected to the output shaft and capable of moving up and down by rotation, the upper surface of the lower nut being in close contact with the upper surface of the lower nut to prevent loosening of the lower nut. In addition, a fastening bolt is screw-connected to fastening holes formed in the upper nut and the lower nut, respectively, to simultaneously fasten the upper nut and the lower nut, thereby supporting the lower nut so that it does not loosen.

[0008] According to the present invention, the bearing supporting the rotation of the output shaft of a wind turbine has its preload determined by the position of the lower nut that contacts it from above. Here, the lower nut is supported by the upper nut so as not to loosen. Moreover, since the fastening bolt simultaneously maintains the upper nut and the lower nut in a fastened state, it is expected that the loosening of the lower nut, which actually contacts the bearing and sets the preload, can be reliably prevented.

[0009] Figure 1 is an example cross-sectional view of a drive for a wind turbine.

[0010] Figure 2 is an example diagram showing a structure equipped with a conventional lock nut.

[0011] Figure 3 is an exemplary cross-sectional view showing the structure of the preload maintenance device of the present invention.

[0012] Hereinafter, the present invention will be examined in more detail based on embodiments illustrated in the drawings. Fig. 1 schematically illustrates the entire drive (DCN type) of a wind turbine. In a wind turbine having this configuration, Fig. 2, related to the preload maintenance device, is an enlarged view of part A of Fig. 1.

[0013] As illustrated in Fig. 2, a pair of nuts (22, 24) are screw-connected to the output shaft (10) of the wind turbine. The lower nut (24) is screw-connected to the outer peripheral threads of the output shaft (10), and then its vertical position is determined by rotation so as to have an appropriate height. The inner ring of a bearing (30) comes into contact with the bottom surface of the lower nut (24), and the preload of the bearing (30) with which the lower nut (24) comes into contact is determined by this contact.

[0014] That is, the preload with which the bearing (30) substantially supports the output shaft (10) is determined by the lower nut (24) that comes into contact with the inner ring (32) of the bearing (30). It can be said that the preload by the lower nut (24) is substantially determined by the upper and lower positions of the lower nut (24). In this state, it is desirable to prevent the upper and lower positions of the lower nut (24) from changing. As described above, the bearing (30) is supported between the housing (50) of the wind turbine drive and the output shaft (10).

[0015] The vertical position of the lower nut (24) can actually be regulated by preventing the lower nut (24) from rotating, which can be said to have the same meaning as maintaining the preload applied to the bearing (30) unchanged. To prevent such movement of the lower nut (24), the upper nut (22) is screwed onto the upper portion of the output shaft (10). The upper nut (22) is screwed onto the outer periphery of the output shaft (10) and rotates downward, thereby maintaining the lower nut (24) in a tightly closed state.

[0016] In this way, a pair of nuts (22, 24) are screw-connected to the output shaft (10) in a state of being in close contact with each other, and the lower nut (24), which is in contact with the bearing (30) from below and applies a certain preload, can be said to have almost no risk of loosening toward the top. Therefore, in this state where a pair of nuts (22, 24) are in close contact with each other, the lower nut (24) determines the preload applied to the bearing (30), and the upper nut (22) in close contact with the lower nut (24) maintains the upper and lower positions so that the lower nut (24) does not loosen.

[0017] In this way, if the lower nut (24) applies a preload to the bearing (30) and the upper nut (22) is kept in close contact with the upper portion thereof, as described above, there will be almost no concern about the lower nut (24) coming loose as it rotates upward. Here, it is thought that there is no limitation on the direction of the screw threads of a pair of nuts (22, 24). It is possible for the screw threads to be formed in the same direction, or it is also possible for the screw threads to be formed in opposite directions.

[0018] And according to the present invention, a mechanical configuration is applied to prevent the lower nut (24) from loosening, i.e., to prevent it from moving upward as much as possible. As shown in Fig. 2, the present invention has a configuration in which a fastening bolt (40) is screw-connected with the inner peripheral threads of fastening holes (23, 25) formed in the upper nut (22) and the lower nut (24), respectively.

[0019] In this way, when the upper nut (22) and the lower nut (24) are fastened to each other by the fastening bolt (40), loosening of the lower nut (24) can be prevented even more. In this case, if the threads of the lower nut (24) and the upper nut (22) are formed in opposite directions, loosening of the lower nut (24) is thought to be impossible.

[0020] Here, it is preferable that a head groove (23a) into which the head of the fastening nut (40) can be inserted is formed on the upper portion of the fastening hole (23) of the upper nut (22). When the head of the fastening bolt (40) is accommodated in the head groove (23a) in this way, the head of the fastening bolt (40) does not actually protrude upward, so it will be easy to understand that the configuration can have a simple overall appearance.

[0021] It is believed that various modifications are possible within the scope of the basic technical concept of the present invention as discussed above. Furthermore, it is natural, in keeping with the provisions of the Patent Act, that the scope of protection of the present invention should be interpreted based on the scope set forth in the claims.

Claims

1. The output shaft of a wind turbine with a portion of the outer periphery having threads; A lower nut that is screw-connected to the output shaft and can move up and down by rotation, and whose bottom surface is in contact with the bearing and can set a preload; An upper nut that is screw-connected to the output shaft and can move up and down by rotation, and is in close contact with the upper surface of the lower nut to prevent loosening of the lower nut; and A wind turbine output bearing preload maintenance device comprising a fastening bolt that is screw-connected to fastening holes formed in the upper nut and lower nut, respectively, and fastens the upper nut and lower nut.

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