Patent Application
20110143880
The present disclosure relates in general to wind turbines, and more particularly to drivetrains for generators in wind turbines.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known foil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During operation of the wind turbine, many various loads may be experienced by various components of the wind turbine. In particular, the drivetrain, which may include the shaft, gearbox, generator, and various components thereof, may experience various loads. These loads may be experienced due to wind loading of the rotor blades. The loads experienced by the rotor blades may be transmitted from the rotor blades to these various components.
For example, during operation, axial loads may be experienced by the shaft due to, for example, the thrust of the rotor blades. These axial loads can be transmitted from the shaft to the bearings surrounding and supporting the shaft, and to the gearbox connected to the shaft. Exposure to these axial loads can stress the bearings and gearbox and potentially cause premature failure of these components.
Further, during operation, bending loads may be experienced by the shaft due to, for example, wind gusts that affect the rotor blades. These bending loads can be transmitted from the shaft to the gearbox connected to the shaft. Exposure to these bending loads can stress the gearbox and potentially cause premature failure of various components of the gearbox.
Thus, an improved drivetrain for a wind turbine would be desired in the art. For example, a drivetrain that can offset or isolate various loads experienced by the drivetrain during operation of the wind turbine would be advantageous.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one embodiment, a drivetrain for a generator in a wind turbine is disclosed. The drivetrain includes an input shaft configured to provide an input rotational speed, and a planetary gearbox in communication with the input shaft. The planetary gearbox includes a stationary carrier and a plurality of rotatable gears. The planetary gearbox is configured to convert the input rotational speed to an output rotational speed. The drivetrain additionally includes an output shaft in communication with the planetary gearbox. The output shaft is configured to rotate at the output rotational speed. The drivetrain further includes a load isolation device disposed between the input shaft and the planetary gearbox. The load isolation device is configured to reduce transmission to the planetary gearbox of bending loads on the input shaft.
In another embodiment, a drivetrain for a generator in a wind turbine is disclosed. The drivetrain includes an input shaft configured to provide an input rotational speed, and a planetary gearbox in communication with the input shaft. The planetary gearbox includes a stationary carrier, a rotatable ring gear, a plurality of rotatable planetary gears, and a rotatable sun gear. Each of the rotatable ring gear, the plurality of rotatable planetary gears, and the rotatable sun gear includes a plurality of helical gear teeth. The planetary gearbox is configured to convert the input rotational speed to an output rotational speed. The drivetrain further includes an output shaft in communication with the planetary gearbox, the output shaft configured to rotate at the output rotational speed. The plurality of helical gear teeth are configured to offset axial loads on the input shaft.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
The hub 18 may be configured to accept the rotor blades 16 thereon. For example, the hub 18 may include a plurality of blade flanges (not shown). The blade flanges may be configured to engage mating flanges (not shown) on the rotor blades 16 to mount the rotor blades 16 to the flanges, and thus to the hub 18.
As shown in
In general, the rotor blades 16 may be configured to rotate the rotor 24 of the generator 22. Thus, the generator 22, such as the rotor 24, may be operably connected to the hub 18. Operation of the rotor blades 16 rotates the hub 18, which rotates the rotor 24 and thus operates the generator 22. Thus, a drivetrain 28 for the generator 22 may be provided between the hub 18 and the rotor 24 to provide the operable connection between the hub 18 and the rotor 24.
As shown in
During operation of the wind turbine 10, the input shaft 30 may be subjected to a variety of loads. For example, the input shaft 30 may experience axial loads 36 and/or bending loads 38 during operation. The drivetrain 28 of the present disclosure, as discussed below, may be generally configured to isolate and/or offset these loads in order to reduce stresses on the drivetrain 28 components and reduce the possibility or premature failure of the drivetrain 28 components.
The input shaft 30 may extend through and be supported by at least one support housing 40 or a plurality of support housings 40. For example, a forward housing 42 and, in some embodiments, an aft housing (not shown), may be provided to support the input shaft 30. The housings 40 may include bearings configured to interact with the input shaft. For example, the forward housing 42 may include a locating bearing 46 therein, while the aft housing may include a floating bearing (not shown) therein. The locating bearing 46 may generally accept a portion of the axial load 36 from the input shaft 30. It should be understood that the present disclosure is not limited to locating bearings and floating bearings positioned in housings as described above, and rather that any suitable bearings and housings are within the scope and spirit of the present disclosure.
As shown in
In exemplary embodiments, the planetary gearbox 50 is a single stage planetary gearbox 50. Thus, the input rotational speed may be converted to the output rotational speed through a single stage of various mating gears, as discussed below. Alternatively, however, the planetary gearbox 50 may be a multiple stage planetary gearbox 50, and the input rotational speed may be converted to the output rotational speed through multiple stages of various mating gears.
The planetary gearbox 50 comprises a stationary carrier 52 and a plurality of rotatable gears. The stationary carrier 52 supports the planetary gearbox 50 and the various rotatable gears therein, and includes various axes for various of the rotatable gears to rotate about. The stationary carrier 52 may further provide various advantages, such as allowing for more efficient lubrication of the planetary gearbox 50. In exemplary embodiments, the planetary gearbox 50 comprises the stationary carrier 52 and a rotatable ring gear 54, at least one or a plurality of rotatable planetary gears 56, and a rotatable sun gear 58. While in some exemplary embodiments the planetary gearbox 50 includes four planetary gears 56, it should be understood that more or less than four planetary gears 56 are within the scope and spirit of the present disclosure.
As shown in
In some exemplary embodiments, as shown in
It should be understood, however, that the gear teeth 64, 66, 68 need not be helical gear teeth. For example, in some embodiments, the gear teeth 64, 66, 68 may be generally axial with respect to an axial centerline through the respective gears 54, 56, 58.
In exemplary embodiments, the ring gear 54 may drive the planetary gearbox 50. Thus, the ring gear 54 and the input shaft 30 may be in communication such that the input rotational speed of the input shaft 30 is provided to the ring gear 54. Alternatively, however, the planetary gears 56 or the sun gear 58 may drive the planetary gearbox 50.
The drivetrain 28 of the present disclosure may further include an output shaft 70. The output shaft 70 may be in communication with the planetary gearbox 50 configured to rotate at the output rotational speed. In exemplary embodiments as shown in
The output shaft 70 may be in communication with the generator 22 to rotate the rotor 24. For example, in some embodiments, the output shaft 70 may be directly connected to the rotor 24. In other embodiments, as shown in
In some embodiments, a hub housing 80 may be provided to support the hub 72, and the hub 72 may extend through the hub housing 80. The hub housing 80 may include a suitable bearing 82 configured to interact with the hub 72.
In some embodiments, as shown in
In exemplary embodiments, the drivetrain 28 of the present disclosure may include a load isolation device 100, as shown in
In exemplary embodiments, as shown in
The torque web 102 may be configured to drive the torque ring 104. Thus, the input rotational speed of the input shaft 30 may be provided through the torque web 102 and the torque ring 104 to the planetary gearbox 50. Thus, the input rotational speed may be provided to the planetary gearbox 50, such as to the ring gear 54, through the load isolation device 100. Further, the interaction of the torque web 102 and torque ring 104 such that the torque web 102 drives the torque ring 104 allows the transmission of bending loads 38 in the input shaft 30 to the planetary gearbox 50 to be reduced or eliminated.
For example, in one embodiment as shown in
In another embodiment, as shown in
Thus, the drivetrain 28 of the present disclosure may offset or isolate various loads experienced by the drivetrain 28 during operation of the wind turbine 10. In particular, the drivetrain 28 may offset or isolate axial loads 36 and/or bending loads 38 experienced by the shaft 30 such that various other components of the drivetrain 28, such as locating bearings 46 and/or the planetary gearbox 50, experience less stress and potentially prolonged lifespans.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
