WO2019014884A1

WO2019014884A1 - System and method for securing an outer race of a bearing to a bedplate of a wind turbine

Info

Publication number: WO2019014884A1
Application number: PCT/CN2017/093632
Authority: WO
Inventors: Bo Fu; William Francis Gevers
Original assignee: General Electric Company
Priority date: 2017-07-20
Filing date: 2017-07-20
Publication date: 2019-01-24

Abstract

A main shaft assembly of a wind turbine (10) includes a main shaft (34) secured to a bedplate (48) of the wind turbine (10) and a bearing (54, 58) seated within the bedplate(48). The bearing (54, 58) is held in place via a cover (68) that is secured to a mounting surface (49) of the bedplate. Moreover, the bearing (54, 58) includes an inner race (56, 64), an outer race (55, 62), a plurality of roller elements (57, 66) arranged therebetween. In addition, the bearing (54, 58) engages the main shaft (34) so as to provide rotation thereof. The main shaft assembly further includes a flexible member (72) arranged between the outer race of the bearing (54, 58) and the cover (68). As such, when the flexible member is compressed, a gap between the mounting surface of the bedplate (48) and the cover (68) is reduced or closed.

Description

SYSTEM AND METHOD FOR SECURING AN OUTER RACE OF A BEARING TO A BEDPLATE OF A WIND TURBINE

FIELD

The present subject matter relates generally to wind turbines, and more particularly to systems and methods for securing an outer race of a bearing to bedplate of a wind turbine.

BACKGROUND

Windpower 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, a generator, a gearbox, a nacelle, and one or more rotor blades. The nacelle includes a rotor assembly coupled to the gearbox and to the generator. The rotor assembly and the gearbox are mounted on a bedplate member support frame located within the nacelle. More specifically, in many wind turbines, the gearbox is mounted to the bedplate member via one or more torque supports or arms. The one or more rotor blades capture kinetic energy of wind using known airfoil 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 ifa 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.

More specifically, the majority of commercially available wind turbines utilize multi-stage geared drivetrains to connect the turbine blades to electrical generators. The wind turns the rotor blades, which spin a low speed shaft, i.e. the main shaft. The main shaft is coupled to an input shaft of the gearbox, which has a higher speed output shaft connected to the generator. Thus, the geared drivetrain aims to increase the velocity of the mechanical motion. Further, the gearbox and the generator are typically supported by one or more bearings and mounted to the bedplate via one or more torque arms or supports.

Such bearings typically include an inner race, an outer race, and a plurality of roller elements arranged therebetween. As such, the outer race is typically stationary, whereas the inner race can rotates to provide rotation of the main shaft. Accordingly, the outer race needs to be firmly clamped axially within the bedplate. As such, the bearings are typically held in place via a cover that is mounted to the bedplate.

Due to machining tolerances, however, a gap exists between the cover flange and the bedplate mounting surface. Such gap needs to be closed or at least reduced to effectively hold the outer race in place. Thus, conventional systems utilize bolts for clamping the cover flange to the bedplate to close the gap. However, in such systems, there are often not enough bolts to perfectly close the gap and such bolts may become damaged due extreme and/or fatigue loads acting on the bolts. In addition, the working life of bolts under such loads is significantly reduced and can cause bolt failure. To make the gap as small as possible, the bearing housing can be designed with tight tolerances, however, such design is costly.

Thus, the art is continuously seeking new and improved systems and methods for securing an outer race of a bearing to bedplate of a wind turbine.

BRIEF DESCRIPTION

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 aspect, the present disclosure is directed to a main shaft assembly of a wind turbine. The main shaft assembly includes a main shaft secured to a bedplate of the wind turbine. Further, the main shaft assembly includes a bearing seated within the bedplate. The bearing is held in place via a cover that is secured to a mounting surface of the bedplate. Moreover, the bearing includes an inner race, an outer race, and a plurality of roller elements arranged therebetween. In addition, the bearing engages the main shaft so as to provide rotation thereof. The main shaft assembly further includes at least one flexible member arrangedbetween the outer race of the bearing and the cover. As such, when the flexible member is compressed, a gap between the mounting surface of the bedplate and the cover is reduced or closed.

In one embodiment, the flexible member (s) is compressed by torqueing one or more fasteners extending through the cover and the mounting surface of the bedplate.

In another embodiment, the flexible member (s) may be one or more springs. In such embodiments, a force from the compressed spring (s) to a predetermined working height is configured to prevent the outer race from rotating. In such embodiments, the inner race of the bearing is configured to rotate so as to provide rotation of the main shaft.

In certain embodiments, the springs (s) may include one or more wave springs. More particularly, the wave spring (s) may be constructed of metal, e.g. such as carbon steel. Further, in several embodiments, a plurality of wave springs may be stacked together.

In additional embodiments, the bearing may correspond to a cylindrical roller bearing.

In another aspect, the present disclosure is directed to a drivetrain assembly of a wind turbine. The drivetrain assembly includes a main shaft secured to a bedplate of the wind turbine, a gearbox rotatably coupled to a downwind end of the main shaft, a generator rotatably coupled to the gearbox via a generator shaft, a first bearing seated within the bedplate at an upwind location, and a second bearing seated within the bedplate at a downwind location. The first bearing is held in place via a first cover that is secured to a first mounting surface of the bedplate. Further, the first bearing includes an inner race, an outer race, and a plurality of roller elements arranged therebetween. Similarly, the second bearing is held in place via a second cover that is secured to a second mounting surface of the bedplate. The second bearing also includes an inner race, an outer race, and a plurality of roller elements arranged therebetween. Moreover, the first and second bearings engage the main shaft so as to provide rotation thereof. The drivetrain assembly also includes at least one flexible member arranged between the outer race of the second bearing and the second cover. As such, when the flexible member (s) is compressed, a gap between the second mounting surface of the bedplate and the cover is closed or reduced. It should be understood that the drivetrain assembly may further include any of the additional features as described herein.

In yet another aspect, the present disclosure is directed to a method for securing an outer race of a bearing within a bedplate of a wind turbine. The method includes removing a portion of a first cover flange of a cover of the bearing to create a space between the first cover flange and an outer race of the bearing. The method also includes inserting at least one flexible member in the space between the first cover flange and the outer race where the portion of the first cover flange has been removed. Further, the method includes compressing the flexible member (s) so as to close a gap between a second cover flange and a mounting surface of the bedplate, wherein closing the gap secures the outer race of the bearing to the bedplate. It should be understood that the method may further include any of the additional step and/or features as described herein.

In addition, in one embodiment, the step of compressing the flexible member (s) so as to close the gap between the second cover flange and the mounting surface of the bedplate may include torqueing a plurality of fasteners extending through the second cover flange and the mounting surface of the bedplate such that the first cover flange compresses the flexible member (s) .

These and other features, aspects and advantages of the present invention will be further supported and described 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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 illustrates a perspective view of one embodiment of a wind turbine according to the present disclosure；

FIG. 2 illustrates a perspective view of a simplified, internal view of one embodiment of a nacelle of a wind turbine according to the present disclosure, particularly illustrating a drivetrain assembly having a single main bearing unit；

FIG. 3 illustrates a cross-sectional view of one embodiment of certain drivetrain components of a wind turbine according to the present disclosure, particularly illustrating a drivetrain assembly having a dual main bearing unit；

FIG. 4 illustrates a detailed cross-sectional view of a portion of the drivetrain assembly of the wind turbine, particularly illustrating a gap between a cover of a bearing and a mounting surface of the bedplate；

FIG. 5 illustrates a detailed cross-sectional view of a portion of the drivetrain assembly of the wind turbine, particularly illustrating a flexible member arranged between the cover and the outer race of the bearing according to the present disclosure；

FIG. 6 illustrates a detailed cross-sectional view of the flexible member arranged between the cover and the outer race of the bearing according to the present disclosure； and

FIG. 7 illustrates a flow diagram of one embodiment of a method for securing an outer race of a bearing within a bedplate of a wind turbine according to the present disclosure.

DETAILED DESCRIPTION

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.

Generally, the present disclosure is directed to a main shaft assembly of a wind turbine. The main shaft assembly includes a main shaft secured to a bedplate of the wind turbine. Further, the main shaft assembly includes a bearing seated within the bedplate. The bearing is held in place via a cover that is secured to a mounting surface of the bedplate. Moreover, the bearing includes an inner race, an outer race, and a plurality of roller elements arranged therebetween. In addition, the bearing engages the main shaft so as to provide rotation thereof. The main shaft assembly further includes at least one flexible member arranged between the outer race of the bearing and the cover. As such, when the flexible member (s) is compressed (e.g. via torqueing bolts extending through the cover and the mounting surface of the bedplate) , a gap between the mounting surface of the bedplate and the cover is reduced or closed.

Thus, the present disclosure provides many advantages not present in the prior art. For example, by utilizing the deformation of the flexible member when the bolts are torqued, the cover fully contacts the mounting surface of the bedplate and maintains the clamping force to the outer race of the bearing. As such, the gap between the cover flange and the mounting surface of the bedplate is reduced or eliminated. Further, the system and method of the present disclosure prevents the outer race of the bearing from spinning radially in bearing bore. In addition, the system and method of the present disclosure prevents the bolts from bending.

Referring now to the drawings, FIG. 1 illustrates a perspective view of one embodiment of a wind turbine 10 according to the present disclosure. As shown, the wind turbine 10 generally includes a tower 12 extending from a support surface 14, a nacelle 16 mounted on the tower 12, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outwardly from the hub 20. For example, in the illustrated embodiment, the rotor 18 includes three rotor blades 22. However, in an alternative embodiment, the rotor 18 may include more or less than three rotor blades 22. Each rotor blade 22 may be spaced about the hub 20 to facilitate rotating the rotor 18 to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy. For instance, the hub 20 may be rotatably coupled to an electric generator 24 (FIG. 2) positioned within the nacelle 16 to permit electrical energy to be produced.

The wind turbine 10 may also include a wind turbine controller 26 centralized within the nacelle 16. However, in other embodiments, the controller 26 may be located within any other component of the wind turbine 10 or at a location outside the wind turbine 10. Further, the controller 26 may be communicatively coupled to any number of the components of the wind turbine 10 in order to control the components. As such, the controller 26 may include a computer or other suitable processing unit. Thus, in several embodiments, the controller 26 may include suitable computer-readable instructions that, when implemented, configure the controller 26 to perform various different functions, such as receiving, transmitting and/or executing wind turbine control signals.

Referring now to FIGS. 2-5, various views of the drivetrain assembly of a wind turbine, such as the wind turbine 10 of FIG. 1, are illustrated. FIG. 2 illustrates a simplified, internal view of one embodiment of the nacelle 16 of the wind turbine 10 shown in FIG. 1, particularly illustrating certain drivetrain components of a drivetrain assembly having a single main bearing unit. FIG. 3 illustrates a cross-sectional view of one embodiment of several drivetrain components of a dual-bearing drivetrain assembly of the wind turbine 10 according to the present disclosure. FIG. 4 illustrates a detailed cross-sectional view of a portion of the drivetrain assembly of the wind turbine 10, particularly illustrating a gap 70 between a cover 68 of a bearing 58 and a mounting surface of the bedplate 48. FIG. 5 illustrates a detailed cross-sectional view of a portion of the drivetrain assembly of the wind turbine 10, particularly illustrating a flexible member 72 arranged between the cover 68 and the outer race 62 of the bearing 58, which will be discussed in more detail below. As shown in FIG. 2, the generator 24 may be coupled to the rotor 18 for producing electrical power from the rotational energy generated by the rotor 18. Further, as shown in FIGS. 2 and 3, the rotor 18 may include a main shaft 34 rotatable via a main bearing 54 coupled to the hub 20 for rotation therewith. The main shaft 34 may, in turn, be rotatably coupled to a gearbox output shaft 36 of the generator 24 through a gearbox 30. More specifically, as shown in FIGS. 3 and 4, the main shaft 34 is typically supported by one or

more bearings

54, 58. For example, as shown, an upwind end of the shaft 34 may be supported by a first or main bearing 54 and a downwind end of the shaft 34 may be supported by a second bearing 58. More specifically, as shown, the main bearing 54 generally corresponds to a tapered roller bearing having an inner race 56, an outer race 55, and a plurality of roller elements 57 arranged therebetween. In further embodiments, the main bearing 54 may be any suitable bearing in addition to tapered roller bearings, including for example, a spherical roller bearing, a cylindrical roller bearing, a ball bearing, or any other suitable bearing. In addition, as shown, the second bearing 58 generally corresponds to a cylindrical roller bearing having an inner race 62, an outer race 60, and a plurality of cylindrical roller elements 66 arranged therebetween.

In addition, as shown, the

bearings

54, 58 may be held in place via first and second bearing covers 60, 68 that are mounted at the upwind and downwind ends of the shaft 34, respectively. Further, as shown particularly in FIGS. 4 and 5, the

covers

60, 68 may include one or more cover flanges. For example, as shown, the second cover 68 includes, at least, a first cover flange 74 and a second cover flange 75. In addition, as shown, one or more seal rings 59, 63 may be configuredbetween the

covers

60, 68 and the

bearings

54, 58. For example, in certain embodiments, the seal ring 59 may correspond to a labyrinth seal that prevents leakage of bearing fluids. Further, as shown, the

bearings

54, 58 may be mounted to the bedplate member 48 of the nacelle 16 via one or more torque supports 50.

Referring back to FIG. 2, the gearbox 30 may include a gearbox housing 38 that is connected to the bedplate 48 by one or more torque arms 50. As is generally understood, the main shaft 34 provides a low speed, high torque input to the gearbox 30 in response to rotation of the rotor blades 22 and the hub 20. Thus, the gearbox 30 thus converts the low speed, high torque input to a high speed, low torque output to drive the gearbox output shaft 36 and, thus, the generator 24.

Referring particularly to FIG. 4, a partial cross-sectional view of a portion of the drivetrain assembly of the wind turbine 10, particularly illustrating a gap 70 between the second cover flange 75 of the cover 68 and the mounting surface 49 of the bedplate 48, is illustrated. As mentioned, this gap 70 exists due to machining tolerances and needs to be closed or at least reduced to effectively hold the outer race 62 of the bearing 58 in place. Thus, as shown, fasteners or bolts 76 are used for clamping the second cover flange 75 to the bedplate 48 to close the gap 70. However, in such systems, there are often not enough bolts 76 to completely close the gap 70. In addition, such bolts 76 may become damaged due extreme and/or fatigue loads acting thereon. In addition, the working life of the bolts 76 under such loads is significantly reduced and can cause bolt failure.

Accordingly, as shown in FIGS. 5 and 6, various views of the main shaft assembly according to the present disclosure are illustrated, particularly illustrating at least one flexible member 72 arranged between the outer race 62 of the bearing 58 and the second cover flange 74 of the cover 68 so as to reduce or eliminate the gap 70 between the second cover flange 75 and the mounting surface 49 of the bedplate 48. More specifically, when the flexible member (s) 72 is compressed, the gap 70 is reduced or closed. For example, in one embodiment, the flexible member (s) 72 is compressed by torqueing the bolts 76 extending through the cover 68 and the mounting surface 49 of the bedplate 48.

To install the flexible member (s) 72, a portion of the first cover flange 74 of the cover 68 may need to be removed. Thus, in one embodiment, a portion of the first cover flange 74 of the cover 68 may be removed via machining (e.g. via cutting or grinding) to create a space for the flexible member (s) 72. Once installed, the flexible member (s) 72 is configured to compress and expand between a free height and a working height. As such, the working height can be calculated to be within the preserved axial gap between the first cover flange 74 of the cover 68 and the outer race 64 of the bearing 58.

As shown particularly in FIG. 6, the flexible member (s) 72 may be one or more springs. More specifically, as shown, the spring (s) may include one or more wave springs. As used herein, a wave spring generally refers to a spring made up of a pre-hardened flat wire. During the manufacturing process, waves are added to give it a spring effect. As such, the number of turns and waves can be easily adjusted to accommodate stronger force or meet specific requirements. In addition, the wave spring (s) may be constructed of metal, e.g. such as carbon steel. Further, in several embodiments, the wave spring (s) may be constructed of multiple layers (i.e. a plurality of springs stacked on top of each other) . In such embodiments, a force from the compressed spring (s) to a predetermined working height is configured to prevent the outer race 62 of the bearing 58 from rotating, whereas the inner race 64 of the bearing 58 is configured to rotate so as to provide rotation of the main shaft 34.

Referring now to FIG. 7, a flow diagram of one embodiment of a method 100 for securing the outer race 62 of the bearing 58 within the bedplate 48 of the wind turbine 10 is illustrated. As shown at 102, the method 100 includes removing a portion of the first cover flange 74 of the cover 68 of the bearing 58 to create a space between the first cover flange 74 and the outer race 62 of the bearing 58. As shown at 104, the method 100 includes inserting one or more flexible members 72 in the space between the first cover flange 74 and the outer race 62, i.e. where the portion of the first cover flange 64 has been removed. As shown at 106, the method 100 includes compressing the flexible member (s) 72 so as to close the gap 70 between the second cover flange 75 and the mounting surface 49 of the bedplate 48. As such, closing the gap 70 also secures or clamps the outer race 62 of the bearing 68 to or within the bedplate 48.

In addition, in one embodiment, the step of compressing the flexible member (s) 72 so as to close the gap 70 between the second cover flange 75 and the mounting surface 49 of the bedplate 48 may include torqueing a plurality of fasteners 76 extending through the second cover flange 75 and the mounting surface 49 of the bedplate 48 such that the first cover flange 74 compresses the flexible member (s) 72.

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 andperforming 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.

Reference Character	Component
10	Wind Turbine
12	Tower
14	Support Surface
16	Nacelle
18	Rotor
20	Rotatable Hub
22	Rotor Blades
24	Generator
26	Controller
30	Gearbox
34	Main Shaft
36	Gearbox Output Shaft
38	Gearbox Housing
48	Bedplate
49	Mounting Surface
50	Torque Arm
54	Main Bearing
55	Outer Race
56	Inner Race
57	Roller Elements
58	Second Bearing
59	Seal Ring/Labyrinth Seal
60	Cover
62	Outer Race
63	Seal Ring/Labyrinth Seal
64	Inner Race
66	Roller Elements
68	Cover
70	Gap
72	Flexible Member
74	First Cover Flange
75	Second Cover Flange
76	Bolts

100	Method
102	Method Step
104	Method Step
106	Method Step

Claims

A main shaft assembly of a wind turbine, the main shaft assembly comprising:

a main shaft secured to a bedplate of the wind turbine；

a bearing seated within the bedplate, the bearing held in place via a cover that is secured to a mounting surface of the bedplate, the bearing comprising an inner race, an outer race, and a plurality of roller elements arranged therebetween, the bearing engaging the main shaft so as to provide rotation thereof,

at least one flexible member arranged between the outer race of the bearing and the cover, wherein, when the at least one flexible member is compressed, a gap between the mounting surface of the bedplate and the cover is closed.
The main shaft assembly of claim 1, wherein the at least one flexible member is compressed by torqueing one or more fasteners extending through the cover and the mounting surface of the bedplate.
The main shaft assembly of claim 1, wherein the at least one flexible member comprises one or more springs.
The main shaft assembly of claim 3, wherein a force from the one or more springs when compressed to a predetermined working height prevents the outer race from rotating.
The main shaft assembly of claim 4, wherein the inner race of the bearing rotates so as to provide rotation of the main shaft.
The main shaft assembly of claim 3, wherein the one or more springs comprises one or more wave springs.
The main shaft assembly of claim 6, wherein the one or more wave springs is constructed of metal.
The main shaft assembly of claim 6, wherein the one or more wave springs comprise a plurality of layers of wave springs.
The main shaft assembly of claim 1, wherein the bearing comprises a cylindrical roller bearing.
A drivetrain assembly of a wind turbine, the drivetrain assembly comprising:

a main shaft secured to a bedplate of the wind turbine；

a gearbox rotatably coupled to a downwind end of the main shaft；

a generator rotatably coupled to the gearbox via a generator shaft；

a first bearing seated within the bedplate at an upwind location, the first bearing held in place via a first cover that is secured to a first mounting surface of the bedplate, the first bearing comprising an inner race, an outer race, and a plurality of roller elements arranged therebetween；

a second bearing seated within the bedplate at a downwind location, the second bearing held in place via a second cover that is secured to a second mounting surface of the bedplate, the secondbearing comprising an inner race, an outer race, and a plurality of roller elements arranged therebetween, the first and second bearings engaging the main shaft so as to provide rotation thereof； and,

at least one flexible member arranged between the outer race of the second bearing and the second cover, wherein, when the flexible member is compressed, a gap between the second mounting surface of the bedplate and the cover is closed.
The drivetrain assembly of claim 10, wherein the at least one flexible member is compressed by torqueing one or more fasteners extending through the second cover and the second mounting surface of the bedplate.
The drivetrain assembly of claim 10, wherein the at least one flexible member comprises one or more springs.
The drivetrain assembly of claim 12, wherein a force from the one or more springs when compressed to a predetermined working height prevents the outer race from rotating, and wherein the inner race of the bearing engages the main shaft so as to provide rotation thereof.
The drivetrain assembly of claim 12, wherein the one or more springs comprises one or more wave springs.
The drivetrain assembly of claim 12, wherein the one or more wave springs is constructed of metal.
The drivetrain assembly of claim 10, wherein the second bearing comprises a cylindrical roller bearing.
The drivetrain assembly of claim 10, wherein the first bearing comprises a tapered roller bearing, and wherein the second bearing comprises a cylindrical roller bearing.
A method for securing an outer race of a bearing within a bedplate of a wind turbine, the method comprising:

removing a portion of a first cover flange of a cover of the bearing to create a space between the first cover flange and an outer race of the bearing；

inserting at least one flexible member in the space between the first cover flange and the outer race where the portion of the first cover flange has been removed； and,

compressing the at least one flexible member so as to close a gap between a second cover flange and a mounting surface of the bedplate, wherein closing the gap secures the outer race of the bearing to the bedplate.
The method of claim 18, wherein the at least one flexible member comprises one or more wave springs.
The method of claim 18, wherein compressing the at least one flexible member so as to close the gap between the second cover flange and the mounting surface of the bedplate further comprises torqueing a plurality of fasteners extending through the second cover flange and the mounting surface of the bedplate such that the first cover flange compresses the at least one flexible member.