DE102022134122A1 - Spherical roller bearings for a wind turbine and wind turbine - Google Patents

Abstract

The invention relates to a spherical roller bearing (114) for a wind turbine (100) with an outer bearing ring (120), with an inner bearing ring (118), with a first roller row (126) of rolling elements (122) and with a second roller row (128) of rolling elements (124), wherein the rolling elements (122, 124) of both roller rows (126, 128) each have (136, 138) running surfaces by means of which they roll on raceways (130, 132, 134) formed by the two bearing rings (118, 120). The rolling elements (122) of the first row of rollers (126) have a first layer (140) on their respective running surfaces (136) and the rolling elements (124) of the second row of rollers (128) have a second layer (142) on their respective running surfaces (138). The first layer (140) and the second layer (142) are designed differently from one another. The invention also relates to a wind turbine (100).

Description

The invention relates to a spherical roller bearing for a wind turbine, which has an outer bearing ring, an inner bearing ring and a first row of rolling elements and a second row of rolling elements. The rolling elements of both rows of rollers roll on raceways formed by the two bearing rings. The invention also relates to a wind turbine with such a spherical roller bearing.

Wind turbines with rotor blades are well known in the art and are used to convert wind energy into electrical energy. Wind turbines are typically equipped with a main bearing that is subject to wear. A rotor shaft of the wind turbine is typically supported in a main bearing using a spherical roller bearing, as such a bearing can absorb both radial forces and axial forces and can compensate for misalignments caused by manufacturing or load, for example.

From the WO2014/062922 A1 is a rolling bearing of a wind turbine designed as a spherical roller bearing, in which the rolling elements of the two rows of rollers are arranged with different contact angles, i.e. angles of inclination of the rolling element longitudinal axes relative to the bearing axis of rotation, between the bearing inner ring and the bearing outer ring.

An object underlying the invention is to provide a concept for a spherical roller bearing which contributes to a particularly reliable operation of a wind turbine, in particular through low-wear operation of the spherical roller bearing.

The problem is solved by the subject matter of patent claim 1. Further developments are specified in the subclaims.

Accordingly, according to the invention, a spherical roller bearing for a wind turbine is disclosed. The spherical roller bearing has an outer bearing ring, an inner bearing ring and a first roller row of rolling elements and a second roller row of rolling elements. The rolling elements of both roller rows each have running surfaces by means of which they roll on raceways formed by the two bearing rings. The rolling elements of the first roller row have a first layer on their respective running surfaces and the rolling elements of the second roller row have a second layer on their respective running surfaces. The first layer and the second layer are designed differently.

The invention provides different layers for the rolling elements of both rows of rollers, for example on their outer surfaces that come into contact with the raceways, whereby in the spherical roller bearing according to the invention different coating measures or layer processing measures are combined or can be combined. The inventor has recognized that such a measure is particularly advantageous in wind turbines, since the raceways and/or running surfaces of the rolling elements for the two rows of rollers are loaded to different degrees depending on the operating situation. For example, both rows of rolling bearings, in particular the raceways and/or the running surfaces of the rolling elements of both rows of rolling bearings, are loaded in a so-called spin operation of the wind turbine and/or at low wind speeds (for example less than 5 m/s) essentially by the resulting weight force acting on the spherical roller bearing. If the wind speed increases, an increasing axial thrust shifts the load to the raceway and/or the running surfaces of the rolling elements facing away from the rotor. In particular, the rotor-side raceway or the rotor-side running surfaces are subjected to less and less stress as the wind speed increases.

The invention offers a number of advantages. With a combination of different layers for the rolling elements of both rows of rollers, the spherical roller bearing is designed in such a way that it can be adapted to the loads that differ for the two rows of rolling bearings in certain operating situations. This increases reliability and service life. This makes it particularly effective to optimize the reliability of spherical roller bearings, such as those for rotor bearings. In particular, optimal wear protection is made possible. Furthermore, costs can also be reduced by not coating or processing all of the rolling elements (in particular only one row of rolling elements), which is expensive. For example, only the rolling elements that belong to a row of rollers that is subject to greater loads during operation are coated or processed in a costly manner.

These advantages are particularly evident in comparison to only partially coated spherical roller bearings, in which either only all rolling elements, i.e. all rolling elements of both rows of rollers, or the bearing outer ring or inner ring are coated or processed.

The two layers of the rolling elements refer to layers that are each also separated from a core of the corresponding rolling element under A layer in the present context is not understood to mean the outer surface of a "bare" rolling element. The respective layer must be structurally, i.e. physically, physically and/or chemically, for example in terms of structure, different from the rest of the rolling element, in particular the core. The core refers to the part of the rolling element that is located under the layer.

According to at least one embodiment, the rolling elements of the first row of rollers have a first core surrounded by the first layer and the rolling elements of the second row of rollers have a second core surrounded by the second layer, the first layer having a lower hardness than the first core and the second layer having a higher hardness than the second core. This contributes in particular to the above advantages and functions. Furthermore, the low hardness of the first layer contributes to a reduction in the tendency towards extreme roughness tip fracture and micropitting in the running-in phase, which enables a reduction in running-in damage to the rolling bearing, for example in the rotor bearing. Furthermore, the high hardness of the second layer enables a reduction in surface damage or even prevention of surface damage, so-called "surface damage", of highly loaded bearing raceways. It also contributes to a lower ingress of wear particles into the lubricant. Furthermore, a reduction in costs is also made possible by not all rolling elements (in particular only one row of rolling elements) being expensively coated.

For example, the first layer is a coating that is applied to the first core. Alternatively, the first layer is an integral part of the first core. In other words, the first layer and the first core are integrated into one another. For example, the first layer results from a processing or machining of the running surface of the rolling elements of the first row of rollers, in particular a physical and/or chemical processing or machining. These statements also apply analogously to the second layer and the rolling elements of the second row of rollers. For example, the first core and the second core have the same hardness.

According to at least one embodiment, the first layer is formed by burnishing the running surfaces of the respective rolling elements. This makes it possible, for example, to achieve a first layer with a lower hardness than the first core. The core material is, for example, steel, such as martensitic steel or bainitic steel.

According to at least one embodiment, the second layer is a DLC coating. This makes it possible, for example, to achieve a second layer with greater hardness than the second core.

The two above embodiments contribute significantly to the advantages and functions mentioned at the beginning. A DLC coating significantly reduces the tendency to the aforementioned "surface damage", which increases due to the high specific energy input into the corresponding raceway or raceways through the superposition of high pressure and slip. With browning, the tendency to extreme roughness tip fracture and thus micropitting in the running-in phase is significantly reduced by significantly increasing the lubricant-carrying capacity of the running surface. The increased lubricant-carrying capacity of the running surface also enables, for example, good wetting of the running surface with lubricant during long downtimes or transport times. The combination of these two types of coating represents a particularly advantageous embodiment of the invention.

According to at least one embodiment - in a proper installation state of the spherical roller bearing in the wind turbine - the first row of rollers faces a rotor star and the second row of rollers faces away from the rotor star. The rotor star is understood to mean the rotor blades and the rotor hub. The second row of rollers faces in particular the gearbox and/or a generator.

According to at least one embodiment, the rolling elements of both rows of rollers roll on a common raceway of the outer bearing ring, wherein the common raceway has a third layer that differs from the first layer and/or the second layer at least partially or in sections. The third layer can thus be designed in the same way as the first or the second layer. The third layer can also be designed differently from the other two layers, the first and the second layer. The third layer is formed, for example, by burnishing. This enables the advantages and functions mentioned above, whereby a particularly flexible adaptation to load cases of the spherical roller bearing can be reproduced.

According to at least one embodiment, the rolling elements of the first row of rollers roll on a first raceway of the inner bearing ring, wherein the first raceway of the inner bearing ring has a fourth layer which differs from the first layer and/or the second layer at least partially or in sections.

According to at least one embodiment, the rolling elements of the second row of rollers roll on a second raceway of the inner bearing ring, and wherein the second raceway of the inner bearing ring has a fifth layer which differs from the first layer and/or the second layer at least partially or in sections.

These two designs also contribute to the advantages and functions mentioned above. The first and second raceways of the inner bearing ring can be part of a jointly formed raceway, but they can also be separate raceways, i.e. spatially separated from one another. This can be done, for example, by one or more design measures, such as a collar, shoulders or the like.

According to at least one embodiment, the fourth layer and fifth layer are formed by burnishing the respective raceways.

In addition, a wind turbine is disclosed which has a shaft, in particular a rotor shaft, and a spherical roller bearing according to one of the preceding embodiments, by means of which the shaft is mounted.

The wind turbine essentially enables the aforementioned advantages and functions. The above-mentioned designs and developments of the spherical roller bearing apply analogously.

Further advantages and functions are described in the following detailed description of an embodiment with the aid of the attached figures. Elements of the same construction or function are identified with the same reference numerals across all figures.

• 1 eine schematische, perspektivische Ansicht einer Windenergieanlage, und
• 2 eine schematische Schnittdarstellung eines Pendelrollenlagers gemäß einem Ausführungsbeispiel der Erfindung.

In the figures show:

• 1 a schematic, perspective view of a wind turbine, and
• 2 a schematic sectional view of a spherical roller bearing according to an embodiment of the invention.

1 shows a schematic representation of a wind turbine 100. The wind turbine 100 has a tower 102. The tower 102 is attached to a base by means of a foundation 104. A nacelle 106 is rotatably mounted at an end of the tower 102 opposite the base. The nacelle 106 has, for example, a generator which is connected via a rotor shaft 160 (shown in 2 ) is coupled to a rotor 108. The rotor 108 has one or more rotor blades 110 which are arranged on a rotor hub 112.

During operation, the rotor 108 is set in rotation by an air flow, for example wind. This rotational movement is transmitted to the generator via the rotor shaft 160 and, if necessary, a gear. The generator converts the kinetic energy of the rotor 108 into electrical energy.

2 shows a spherical roller bearing 114 for the wind turbine 100 according to an embodiment of the invention schematically in a half longitudinal center section. By means of the spherical roller bearing 114, for example, the rotor shaft 160 of the wind turbine 100 is mounted in the nacelle 106. It is not excluded to use such a bearing for other purposes of the wind turbine 100.

The spherical roller bearing 114 is mounted in a schematically illustrated bearing housing 116. The spherical roller bearing 114 has an inner bearing ring 118 and an outer bearing ring 120. The spherical roller bearing 114 has identical first rolling elements 122 and second rolling elements 124 (hereinafter also referred to as rolling elements 122 and 124) in the form of barrel rollers, with the rolling elements 122 forming a first row of rollers 126 and the rolling elements 124 forming a second row of rollers 128. The rolling elements 122 and 124 are evenly distributed around the circumference and the two rows of rollers 126 and 128 are arranged axially spaced from one another.

In the intended installation state of the spherical roller bearing 114 in the wind turbine 110, the first row of rollers 126 of rolling elements 122 faces a rotor star, that is, the rotor blades 110 and the rotor hub 112, while the second row of rollers 128 of rolling elements 124 faces away from the rotor star.

The rolling elements 122 and 124 roll on a common, spherical raceway 130 of the outer bearing ring 120. On the inside, the rolling elements 122 roll on a first raceway 132 of the inner bearing ring 118 and the rolling elements 124 roll on a second raceway 134 of the inner bearing ring 118.

To roll on the respective raceways 132, 134, the rolling elements 122 and 124 each have running surfaces 136 and 138 (surfaces that come into contact with the raceways when rolling). The (first) running surfaces 136 of the rolling elements 122 of the first roller row 126 each have a first layer 140 and the (second) running surfaces 138 of the rolling elements per 124 of the second roller row 128 each have a second layer 142. The rolling elements 122 of the first roller row 126 have a first core 144 surrounded by the first layer 140 and the rolling elements 124 of the second roller row 128 have a second core 146 surrounded by the second layer 142.

The first layer 140 and the second layer 142 are formed differently, with the first layer 140 having a lower hardness than the first core 144 and the second layer 142 having a greater hardness than the second core 146. In particular, each first layer 140 is formed by burnishing the running surfaces 136 of the first rolling elements 122. Each second layer 142 is a DLC coating.

The common, spherical raceway 130 of the outer bearing ring 120 has a third layer 148, which is formed by burnishing in a similar way to the first layer 140 and therefore differs from the second layer 142. In other words, the rolling elements 122, 124 of both roller rows 126 and 128 each roll on a burnished raceway 130.

The first raceway 132 and the second raceway 134 of the inner bearing ring 118 have a fourth layer 150 and a fifth layer 152. The fourth and fifth layers 150, 152 are also formed by burnishing and thus differ from the second layer 142.

It is conceivable that - for example for manufacturing reasons - the inner bearing ring 118 and the outer bearing ring 120 are completely burnished. In other words, it is not absolutely necessary to burnish only the respective raceways.

The described spherical roller bearing 114 enables the advantages and functions mentioned at the beginning. Of course, the described solution is not limited to barrel rollers as rolling elements. Instead of a common spherical raceway 130, two separate raceways can also be provided. The rolling elements of one row of rollers can also be arranged at a different oblique angle to the central longitudinal axis (axis of the rotor shaft 160) than the rolling elements of the other row of rollers.

List of reference symbols

100

Wind turbine

102

Tower

104

foundation

106

gondola

108

rotor

110

Rotor blade

112

Rotor hub

114

Spherical roller bearings

116

Bearing housing

118

inner bearing ring

120

outer bearing ring

122

first rolling elements

124

second rolling elements

126

first row of rollers

128

second row of rollers

130

common career

132

first career

134

second career

136

first tread

138

second running surface

140

first layer

142

second layer

144

first core

146

second core

148

third layer

150

fourth layer

152

fifth layer

160

Rotor shaft

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• WO 2014062922 A1 [0003]

Claims (11)

Spherical roller bearing (114) for a wind turbine (100), comprising - an outer bearing ring (120), - an inner bearing ring (118), - a first roller row (126) of rolling elements (122) and a second roller row (128) of rolling elements (124), wherein the rolling elements (122, 124) of both roller rows (126, 128) each have (136, 138) running surfaces by means of which they roll on raceways (130, 132, 134) formed by the two bearing rings (118, 120), wherein the rolling elements (122) of the first roller row (126) have a first layer (140) on their respective running surfaces (136) and the rolling elements (124) of the second roller row (128) have a second layer (142) on their respective running surfaces (138), characterized in that the first layer (140) and the second layer (142) are formed differently from one another. Spherical roller bearings (114) according to Claim 1 , wherein the rolling elements (122) of the first row of rollers (126) have a first core (144) surrounded by the first layer (140) and the rolling elements (124) of the second row of rollers (128) have a second core (146) surrounded by the second layer (142), wherein the first layer (140) has a lower hardness than the first core (144) and wherein the second layer (142) has a greater hardness than the second core (146). Spherical roller bearings (114) according to Claim 1 or 2 , wherein the first layer (140) is formed by burnishing the running surfaces (136) of the respective rolling elements (122). Spherical roller bearing (114) according to one of the preceding claims, wherein the second layer (142) is a DLC coating. Spherical roller bearing (114) according to one of the preceding claims, wherein - in a proper installation state of the spherical roller bearing (114) in the wind turbine (100) - the first row of rollers (126) of rolling elements (122) faces a rotor star and the second row of rollers (128) of rolling elements (124) faces away from the rotor star. Spherical roller bearing (114) according to one of the preceding claims, wherein the rolling elements (122, 124) of both rows of rollers (126, 128) roll on a common raceway (130) of the outer bearing ring (120), wherein the common raceway (130) has a third layer (148) which differs from the first layer (140) and/or the second layer (142) at least partially or in sections. Spherical roller bearings (114) according to Claim 6 , wherein the third layer (148) is formed by burnishing. Spherical roller bearing (114) according to one of the preceding claims, wherein the rolling elements (122) of the first row of rollers (126) roll on a first raceway (132) of the inner bearing ring (118), and wherein the first raceway (132) of the inner bearing ring (118) has a fourth layer (150) which differs from the first layer (140) and/or the second layer (142) at least partially or in sections. Spherical roller bearing (114) according to one of the preceding claims, wherein the rolling elements (124) of the second row of rollers (128) roll on a second raceway (134) of the inner bearing ring (118), and wherein the second raceway (134) of the inner bearing ring (118) has a fifth layer (152) which differs from the first layer (140) and/or the second layer (142) at least partially or in sections. Spherical roller bearings (114) according to Claim 9 combined with Claim 8 , wherein the fourth layer (150) and fifth layer (152) are formed by burnishing the respective raceways (132, 134). Wind energy plant (100), comprising - a shaft, in particular a rotor shaft, - a spherical roller bearing (114) according to one of the preceding claims, via which the shaft is mounted.

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