阅读说明：本技术 滚动轴承和包括滚动轴承的风力涡轮机 (Rolling bearing and wind turbine comprising a rolling bearing ) 是由 A.里蔡夫斯基 于 2020-02-21 设计创作，主要内容包括：本发明涉及滚动轴承和包括滚动轴承的风力涡轮机。特别是用于风力涡轮机(1)的滚动轴承(10)包括：内座圈(12)；外座圈(14)；布置在内座圈(12)和外座圈(14)间的多个滚动元件(19)；及用于润滑滚动轴承(10)的润滑剂(18),其中内座圈(12)和外座圈(14)各自具有轴承表面,该表面具有与滚动元件(19)接触的接触区域(15、28)；内座圈(12)和/或外座圈(14)的轴承表面具有带有用于排斥润滑剂(18)的疏脂表面的部分(16)。所提滚动轴承具有轴承中的润滑剂不会粘附到其对润滑轴承无用的部分的优点。因此滚动轴承可具有更好的润滑,因为润滑剂被引向在座圈和滚动元件间发生接触的接触区域。(The invention relates to a rolling bearing and a wind turbine comprising a rolling bearing. A rolling bearing (10), in particular for a wind turbine (1), comprises: an inner race (12); an outer race (14); a plurality of rolling elements (19) arranged between the inner race (12) and the outer race (14); and a lubricant (18) for lubricating the rolling bearing (10), wherein the inner race (12) and the outer race (14) each have a bearing surface with a contact area (15, 28) in contact with the rolling elements (19); the bearing surface of the inner race (12) and/or the outer race (14) has a portion (16) with a lipophobic surface for repelling a lubricant (18). The proposed rolling bearing has the advantage that the lubricant in the bearing does not adhere to its parts which are not useful for lubricating the bearing. The rolling bearing can thus have better lubrication because the lubricant is directed to the contact area where contact between the raceway and the rolling elements takes place.)

1. Rolling bearing (10), in particular for a wind turbine (1), comprising:

an inner race (12),

an outer race (14),

a plurality of rolling elements (19) arranged between the inner race (12) and the outer race (14), and

a lubricant (18) for lubricating the rolling bearing (10),

wherein the content of the first and second substances,

the inner race (12) and the outer race (14) each having a bearing surface with a contact area (15, 28) in contact with the rolling elements (19),

the bearing surface of the inner race (12) and/or the outer race (14) has a portion (16), the portion (16) having a lipophobic surface (17) for repelling the lubricant (18).

2. Rolling bearing according to claim 1, wherein said portion (16) is directly adjacent to said contact area (15, 28).

3. Rolling bearing according to claim 1 or 2, wherein said portion (16) comprises a lipophobic material.

4. Rolling bearing according to any of claims 1 to 3, wherein the lipophobic surface (17) is formed as a coating.

5. Rolling bearing according to any of claims 1 to 4, wherein said portion (16) comprises a micro-structured material, in particular a micro-porous material.

6. Rolling bearing according to any of claims 1 to 5, characterized in that a sealing portion (30) for sealing the rolling bearing (10) is arranged between the inner race (12) and the outer race (14), and a surface portion (32) directly adjacent to the sealing portion (30) has a lipophobic surface for repelling the lubricant (18).

7. Rolling bearing according to any of claims 1 to 6, wherein the contact area (15, 28) has a lipophilic surface.

8. Rolling bearing according to any of claims 1 to 7, wherein the rolling elements (19) have a lipophilic surface.

9. Rolling bearing according to any of claims 1 to 8, wherein said lubricant (18) is oil.

10. Rolling bearing according to any of claims 1 to 9, wherein said lubricant (18) is a grease.

11. Rolling bearing according to any of claims 1 to 10, wherein said portion (16) comprises a polymer coating.

12. Rolling bearing according to claim 11, characterized in that the polymer coating is a fluoropolymer coating.

13. Rolling bearing according to any of claims 1 to 12, characterized in that the rolling bearing (10) is embodied as a ball bearing, a cylindrical rolling bearing, a spherical rolling bearing and/or a conical rolling bearing.

14. Wind turbine (1) with a rolling bearing (10) according to one of claims 1 to 13 as a main bearing and/or as a blade bearing.

Technical Field

The invention relates to a rolling bearing and a wind turbine comprising such a rolling bearing.

Background

Known wind turbines include rotors having large diameters and may be very heavy. These rotors are supported in bearings capable of withstanding high loads. Furthermore, to optimize efficiency, such bearings preferably have low internal friction. For this purpose, a lubricant is used. However, the lubricant is effective only when a film is formed between portions of the bearing that move relative to each other.

US 8,783,959B 2 describes a bearing cage (bearing cage) for a rolling element bearing having at least one surface with lipophobic and/or oleophobic properties. The lubricant used in the bearing forms a contact angle of at least 90 ° on the surface having lipophobic and/or oleophobic properties.

Disclosure of Invention

It is an object of the present invention to provide an improved rolling bearing, in particular for use in a wind turbine.

According to a first aspect, a rolling bearing, in particular for a wind turbine, is provided. The rolling bearing includes an inner race, an outer race, a plurality of rolling elements disposed between the inner race and the outer race, and a lubricant for lubricating the rolling bearing. The inner race and the outer race each have a bearing surface with a contact area that contacts the rolling elements. The bearing surface of the inner race and/or outer race has the following portions: the portion has a lipophobic surface for repelling lubricant.

Advantageously, due to the lipophobic surface, the lubricant in the rolling bearing does not adhere to the part where it cannot lubricate the rolling elements. Therefore, the rolling bearing has improved lubrication.

Since lubricant is not lost in the regions of the rolling bearing where it is not acting, for example, the portions, the overall rolling resistance or friction of the proposed rolling bearing can be reduced. In particular in rolling bearings for use in devices with long operating times under constant and permanent loads, for example in rolling bearings for use in wind turbines, the service interval or the lifetime of the rolling bearing can be significantly increased. This is due to the more efficient lubrication, thereby reducing wear of the rolling bearing, in particular of the rolling elements and/or races. Thus, an accidental or premature failure of the rolling bearing or a subsequent influence due to poor performance of the rolling bearing can be avoided.

Lubricants, such as oil or grease, are used in particular to reduce the friction between the rolling elements and the races. For this purpose, the lubricant preferably forms a thin layer between the elements moving relative to one another, i.e. the rolling elements and the raceways. To achieve a very low friction, the lubricant preferably represents a liquid with a low viscosity, since such a liquid cannot transfer large shear forces. However, such liquid may be rapidly displaced due to the pressure between the rolling elements and the race applied by the load on the rolling bearing, which is not preferable. Therefore, the lubricant preferably has a certain viscosity.

Thus, depending on the desired operating point of the rolling bearing with respect to load and rotational speed, the lubricant can be optimized with respect to the parameters as described above. Other parameters that may be of interest are the water absorption and/or capacity of the abrasive dust.

The inner and outer races, which may be referred to as inner and outer races respectively, preferably comprise hardened material, such as hardened steel.

The contact area preferably comprises a very hard surface having a high wear resistance. The width of the contact region depends in particular on the geometry of the rolling elements.

The portion has a lipophobic surface, which means that it repels lipids. This is also called lipophobicity. The portion may also be referred to as oleophobic. As used herein, "lipophobic" and "oleophobic" have the same meaning. The lubricant comprises a lipid, such as a fat, oil or fat. Thus, the lubricant is repelled by the surface of the portion. Repulsion means that the adhesion between the lubricant and the parts is relatively low, so that the lubricant will roll off easily when a tangential force against the surface is applied to the lubricant.

Lipophobicity can be measured, for example, by determining the contact angle between a droplet of lubricant and the surface of the moiety. The contact angle may be defined as the angle formed between the surface and a tangent on the interface between the droplet and the cladding phase (surrouding phase) at the boundary line between the lubricant and the cladding phase, e.g. air. The contact angle can be expressed as a static, advancing or receding contact angle. The advancing contact angle is obtained when the volume of the droplet increases during the measurement, i.e. the borderline moves forward (advances). The receding contact angle is obtained when the volume of the droplet decreases during the measurement, i.e. the borderline moves backwards (recedes). The static contact angle is obtained when the volume is fixed and after allowing the droplet to settle (drop). For example, the static contact angle has a value between the value of the advancing contact angle and the value of the receding contact angle.

For example, when the contact angle, preferably the receding contact angle, is greater than 60 °, preferably greater than 90 °, the surface is said to be lipophobic. The contact angle may depend on both the surface properties and the lubricant. For example, the polarity of the lubricant molecule is associated with lipophobicity.

In an embodiment, the portion has a super lipophobic surface. This is the case, for example, when the contact angle is greater than 120 °.

For example, when lubricant is displaced by one of the rolling elements, the lubricant pushed from the contact area to the part does not stick to the part due to the lipophobic properties, but returns to the contact area where it may contribute to the lubrication of the rolling elements. This is particularly advantageous when the lubricant is a grease which tends to adhere to the surface more strongly than the oil.

The proposed rolling bearing can be used in any application. Preferably, the rolling bearing is used in applications requiring rotationally supporting high loads.

According to one embodiment, said portion is directly adjacent to said contact area.

The portion is directly adjacent to the contact region. This means that no space is left between the contact area and the portion. In an embodiment, the portion may be arranged between two contact areas separated by the portion. That is, several separate contact areas and several parts with lipophobic surfaces can be realized.

According to one embodiment, the portion comprises a lipophobic material.

The lipophobic material has a lipophobic surface, providing the mentioned advantages.

According to another embodiment, the lipophobic surface is formed as a coating.

For example, the coating may comprise a polymer coating, particularly a fluoropolymer. Examples are perfluoroalkoxyalkanes (perfluoroalkoxy alkanes), copolymers of tetrafluoroethylene, perfluoroethers (perfluoroethers) or Polytetrafluoroethylene (PTFE).

According to another embodiment, the portion comprises a microstructured material, in particular a microporous material.

For example, the microstructured material has a microstructured surface that further allows for tuning of surface properties, such as interaction with various fluids. In particular, the lipophobic surface properties of the moieties may be enhanced by the use of such materials.

According to another embodiment, a sealing portion for sealing the rolling bearing is arranged between the inner race and the outer race, and a surface portion directly adjacent to the sealing portion has a lipophobic surface for repelling the lubricant.

The seal portion prevents lubricant from escaping from the rolling bearing and prevents dust or dirt and water or moisture from entering the rolling bearing. The sealing portion includes a seal or sealing element. By arranging the lipophobic surface beside the sealing portion, less lubricant will accumulate in the space formed between the rolling element and the sealing portion. This has the advantage that: since this space is not pre-occupied by lubricant adhering to the surface close to the seal, the pressure on the seal caused by the lubricant being pushed towards the seal by the rolling elements is reduced. The sealing properties of the seal are thus improved, which further increases the service life of the rolling bearing.

According to another embodiment, the contact region has a lipophilic surface.

The lipophilic surface may be achieved by applying a lipophilic coating on said contact area. This embodiment has the following advantages, namely: the lubricant preferably adheres to the contact area. This improves lubricant efficiency.

For example, a surface is said to be lipophilic when the contact angle of the lubricant on the surface is less than 90 °, preferably less than 60 °.

According to another embodiment, the rolling element has a lipophilic surface.

This embodiment further improves the efficiency of the lubricant.

According to another embodiment, the lubricant is oil.

Preferably, the oil includes an additive for enhancing its properties. Additives are, for example, detergents and dispersants.

According to another embodiment, the lubricant is a grease.

Fats include oils and certain additives that impart enhanced properties thereto. Fat may be preferred because it may have better properties under high loads or even static conditions.

According to another embodiment, the portion comprises a polymer coating.

The polymer coating has the following advantages: the polymer can be easily tailored with respect to its functional groups. That is, a variety of different functional groups may be implemented, particularly as side groups along the polymer backbone, which have different functional properties in the polymer. Thus, the polymer coating may have certain specific properties in addition to lipophobicity.

According to another embodiment, the coating is a fluoropolymer coating.

According to a further embodiment, the rolling bearing is embodied as a ball bearing, a cylindrical rolling bearing, a spherical rolling bearing and/or a conical rolling bearing.

The rolling bearing may further comprise a cage for fixing the rolling elements in certain positions. Preferably, the cage has at least in part a lipophobic surface. For example, the cage is made of a lipophobic material or coated with a lipophobic coating. This ensures that lubricant does not adhere to the cage.

According to a second aspect, a wind turbine is presented. The wind turbine has the rolling bearing according to the first aspect as a main bearing and/or a blade bearing.

The wind turbine has the following advantages: the efficiency is improved due to the reduced friction. Furthermore, the service life of the rolling bearing is increased because of the reduced wear. Thus, the overall economic efficiency of the wind turbine is significantly improved.

Other possible embodiments or alternatives of the invention also include combinations of features not explicitly mentioned herein above or described below with respect to the examples. Those skilled in the art may also add individual or isolated aspects and features to the most basic form of the invention.

Drawings

Other embodiments, features, and advantages of the present invention will become apparent from the subsequent description and the dependent claims, taken in conjunction with the accompanying drawings in which:

fig. 1 shows a schematic cross-sectional view of one example of a rolling bearing;

fig. 2 shows a schematic cross-sectional view of one example of a shaft rotationally supported by two rolling bearings;

fig. 3 shows a schematic cross-sectional view of another example of a rolling bearing; and

fig. 4 shows a schematic view of a wind turbine.

In the drawings, like reference numbers indicate identical or functionally equivalent elements unless otherwise indicated.

Detailed Description

Fig. 1 shows a schematic cross-sectional view of an example of a rolling bearing 10. The rolling bearing 10 is embodied as a ball bearing. The ball bearing 10 includes an inner race 12 and an outer race 14 made of hardened steel. Rolling elements 19 are arranged between the inner race 12 and the outer race 14. In this case, the rolling elements 19 are balls. The ball bearing 10 may further include a cage (not shown) for retaining the balls 19.

Both the inner race 12 and the outer race 14 are specifically designed on their sides facing each other. In particular, a contact area 15 is arranged at a location where the balls 19 have contact with the inner race 12 or the outer race 14 under normal operating conditions. The contact area 15 is preferably machined to be very hard and strong. Beside the contact area 15 on both sides (side) portions 16 are arranged. The portion 16 is arranged in a position where the balls 19 will not have contact under normal operating conditions. The ball bearing 10 is lubricated by using a lubricant 18 such as oil and/or grease.

The portion 16 has a lipophobic surface 17 (for better overview, reference numerals are shown only on the left side). This is provided, for example, by a lipophobic coating. Thus, the lubricant 18 is repelled from the lipophobic surface 17. That is, the lubricant does not adhere to the lipophobic surface 17. Furthermore, the contact area 15 comprises a lipophilic coating, which provides the contact area 15 with lipophilic properties. Thus, since the portion 16 is lipophobic and the contact area 15 is lipophilic, the lubricant 18 stays on the contact area 15. The lubricant 17 is preferably returned to the contact area 15 even if the lubricant 18 is pushed to the portion 16, for example by the balls 19. Thus, the lubricant 17 remains effective in lubricating the ball bearing 10. That is, friction between the balls 19 and the contact area 15 of both the inner race 12 and the outer race 14 is reduced. In addition, wear of the ball bearing 10 is reduced.

Fig. 2 shows a schematic cross-sectional view of one example of a shaft 22 rotatably supported by two rolling bearings 10, such as the ball bearing 10 described with reference to fig. 1. In fig. 2, only the upper half of the shaft is shown. The shaft 22 is, for example, the shaft of a rotor of the wind turbine 1 (see fig. 3) and has a diameter of 2.5 m. The shaft 22 is rotatably supported about a rotation axis X.

The inner race 12 of the rolling bearing 10 is arranged on the shaft 22. The outer race 14 of the rolling bearing 10 is arranged on the bearing flange 20. For example, the bearing flange 20 is implemented in a housing 4 (see fig. 3) supporting the rotor and the generator (not shown).

By using the rolling bearing 10, the shaft 22 is supported very smoothly and has very low friction. This is due to the fact that by the special design of the inner race 12 and the outer race 14, the lubricant 18 (see fig. 1) is retained in the contact region 15 (see fig. 1) of the rolling bearing 10, as described with reference to fig. 1.

Fig. 3 shows a schematic cross-sectional view of another example of the rolling bearing 10. The rolling bearing 10 has two rows of conical or cylindrical rolling elements 19. In fig. 3, only one half of the rolling bearing 10 is shown, the other half being symmetrically identical. The contact area 15 on the inner and outer races 12, 14 has a width corresponding to the effective length of the rolling elements 19, which is the portion of the rolling elements 19 in contacting engagement with the inner or outer race 12, 14. The rolling elements 19 are held in place and guided, for example, by means of edges 24, 26 formed on the inner race 12. However, instead of or in addition to the edges 24, 26, cages (not shown) may also be employed for guiding the rolling elements 19.

In fig. 3, the portion 16 with the lipophobic surface 17 arranged on both the inner race 12 and the outer race 14 is shown on only one side of the rolling elements 19. However, such a portion 16 may also be present on the other side of the rolling element 19.

The rolling bearing 10 has a fixing element 29 for fixing a sealing element 31 between the inner race 12 and the outer race 14. That is, the sealing portion 30 is disposed between the inner race 12 and the outer race 14. Beside the sealing portion 30 or seal 31 is a surface portion 32 of the inner race 12, which surface portion 32, like the portion 16, has a lipophobic surface. The surface portion 28 of the edge 26 is substantially parallel to the side of the rolling element 19 and is a guide for the rolling element 19. Thus, contact between the rolling elements 19 and the surface portions 28 may occur. The surface portion 28 is thus lubricated by the lubricant 18 (not shown in fig. 3). Thus, the surface portion 28 is not lipophobic, but preferably has a lipophilic surface.

A space a is formed between the rolling elements 19, the inner race 12, the outer race 14 and the fixed elements 29. Since the surface portion 32 has a lipophobic surface, the lubricant 18 does not adhere to it. Therefore, the lubricant 18 accumulated in the space a is reduced. Since the space a is not pre-occupied by the lubricant 18, the pressure of the lubricant 18 that may be exerted on the seal 31 decreases when the lubricant 18 is pushed into the space a by the rolling elements 19. In addition, lubrication of the surface portion 28 is enhanced. Other surfaces than those described herein may be modified to have lipophobic properties.

Fig. 4 shows a schematic view of a wind turbine 1. The wind turbine 1 comprises a rotor with three blades 2. These blades 2 drive a shaft 22 (see fig. 2), which shaft 22 is rotatably supported by two rolling bearings 10, said rolling bearings 10 being, for example, the rolling bearings 10 described with reference to one of fig. 1 to 3. Thus, the rolling bearing 10 is the main bearing of the wind turbine 1. The rolling bearing 10 is fixed with its outer race 14 to a main bearing flange (not shown) arranged in the housing 3 of the wind turbine 1. The shaft 22 drives a generator (not shown) arranged in the housing 3. The housing 3 is arranged on a rod 4. For example, the wind turbine 1 has a height of more than 100m and the rotor of the wind turbine 1 has a diameter of 50m and up to 250 m.