Rotor bearing of a wind turbine

A rotor bearing of a wind turbine, in particular a rotor bearing having an improved and simplified axial introduction of force into the inner ring. It is specified for this purpose that the inner ring of the rolling bearing has a greater axial length with respect to the axial length of the outer ring of the rolling bearing by a section of the inner ring that corresponds to the axial length of the outer ring and has the length being adjoined by additional sections, wherein the axial lengths of these sections differ in size.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase of PCT Appln. No. PCT/DE2020/100143, filed Mar. 3, 2020, which claims priority to DE 102019106276.4, filed Mar. 12, 2019, the entire disclosures of which are incorporated by reference herein.

TECHNICAL FIELD

The disclosure relates to a rotor bearing of a wind turbine, in particular to a rotor bearing having an improved axial introduction of force into the inner ring.

BACKGROUND

A conventional rotor bearing for a wind turbine is known from DE 10 2009 041 747 A1. There, a double-row spherical roller bearing is used as a rolling bearing, which has an inner ring, an outer ring and rolling bodies rolling between the two running rings. The axial length of the inner ring corresponds to the axial length of the outer ring. In order to support a rotor shaft of a wind turbine, it penetrates the bore of the inner ring, while the outer ring of the rolling bearing is received in a housing. The latter can be found in DE 103 10 639 A1. This document also reveals that two shoulders are provided for axially securing the inner ring on a circumferential section of the rotor shaft, which shoulders axially delimit the circumferential section. This axial limitation of the circumferential section is implemented by a shaft shoulder on the side close to the rotor, a separate spacer ring being provided between the shaft shoulder and the inner ring in order to introduce axial forces from the rotor shaft into the inner ring at the smallest possible angle. The axial delimitation of the circumferential section on the side away from the rotor can be implemented by a shaft nut, as can be found in DE 102009 059 655 A1. Even if the rolling bodies of the two roller rows have a symmetrical pressure angle in DE 10 2009 041 7474 A1, the roller row away from the rotor can—as shown in DE 10 2015 204 970 A1—have a larger pressure angle for better absorption of axial forces compared to the roller row close to the rotor.

In addition, the bearing rings do not necessarily have to be designed as closed rings, but—as DE 10 2017 110 742 A1 shows—for better interchangeability of the rolling bearing, they can each be formed by two ring halves, which are held together by clamping rings after completion to form an inner ring, for example, by placing the clamping ring segments forming the clamping ring around the formed inner ring and connecting them by screws screwed through the clamping ring segments.

However, if bearing rings are split radially, the problem arises at high loads that the bearing rings that are split and fastened by clamping rings have a somewhat lower axial stability, which has a detrimental effect on the service life of such rolling bearings.

SUMMARY

The disclosure is therefore based on the object of disclosing a rotor bearing which has a simplified design and is characterized by improved stability.

This object is achieved with a rotor bearing having one or more of the features described herein. Advantageous embodiments and further developments of are listed below and in the claims.

If the inner ring has a first axial section of the length L2, which corresponds to the axial length L3of the outer ring, and has two second sections being axially adjoined by the first section, of different axial lengths L4; L4.1, L4.2, because the inner ring completely fills the circumferential section between the two shoulders of the rotor shaft, the axial force is introduced from the rotor shaft directly into the inner ring at a flatter and therefore advantageous angle, without the need for additional spacer rings that increase the effort. Because the inner ring has a greater axial length in relation to the outer ring and extends as an at least axially one-piece component between the two shoulders of the circumferential section, this one-piece design improves the fit of the inner ring on the rotor shaft overall. This is particularly the case when the section of greater axial length adjoins the side of the inner ring which faces the rotor.

The axial power transmission is further improved if a rolling bearing is a double-row spherical roller bearing, wherein the rolling bodies of the roller row closer to the rotor have a smaller pressure angle compared to the rolling bodies of the other roller row.

If the rolling bearing is designed as a radially split rolling bearing, replacing the rolling bearing is simplified.

A good connection between the inner ring and the rotor shaft is provided when at least two clamping ring segments are provided which, in the connected state, result in a clamping ring, and the inner ring is held together on the rotor shaft by clamping rings that surround the second sections of the inner ring for this purpose.

The seal is simplified if the clamping rings provide at least radially outer circumferential surfaces which form at least one sealing surface interacting with a sealing partner. The sealing surfaces can be in operative connection both with a contacting seal and with a non-contacting counter surface separated by a small distance.

An uninterrupted sealing surface is created when a mutual distance A remaining between the end surfaces of two assembled clamping ring segments is filled with a plastic or metal in such a way that the circumferential surface of one clamping ring segment merges seamlessly into the circumferential surface of the other clamping ring segment. Installation space and material-saving clamp rings are provided when the axial extent of the clamping rings along the rotational axis of the rotor shaft, starting from the center of the bore, differs in size, so sealing surfaces related to the bores are only provided on the side of the clamping rings, on which they are required.

The sealing effect is further improved if seals are provided between the clamping rings and the second sections of the inner rings.

DETAILED DESCRIPTION

The embodiments will now be explained in more detail with reference to the figures.

InFIG.1, a rotor shaft1of a wind turbine is shown. A rotor2, indicated inFIG.1, which drives the rotor shaft1, is connected to one end of this rotor shaft1. In this exemplary embodiment, this rotor shaft1is supported by a rolling bearing3in the form of a two-row spherical roller bearing, which has an inner ring4, an outer ring5, rolling bodies6, which are arranged in two rows between the bearing rings4,5, and cage elements,12(not described in more detail) which space the rolling bodies6apart in the circumferential direction. The rolling bodies6of the different roller rows roll at different pressure angles α, β between the two bearing rings4,5, the rolling bodies6of the roller row facing away from the rotor2being at the greater pressure angle β compared to the rolling bodies6of the other roller row.

In order to facilitate the replacement of the rolling bearing3, both the inner ring4and the outer ring5are radially split, wherein each of the two bearing rings4,5of two half-shells4.1,4.2;5.1,5.2(only partially visible inFIG.1) complementing each other to form a bearing ring4.5is formed. The hatching shown discloses that the two half-shells4.1,4.2of the inner ring4and the two half-shells5.1,5.2of the outer ring5are adjacent to one another in the assembled state at 9 o'clock and 3 o'clock.

The rolling bearing3is connected to the rotor shaft1with its inner ring4. In the present case, this is implemented in such a way that the inner ring4or the half-shells4.1,4.2forming the inner ring4are placed around the rotor shaft1. In order to preclude an axial displacement of the formed inner ring4along the rotor shaft1, a shaft shoulder7on the rotor side is in contact with the first end faces8.1of the formed inner ring4. On the circumferential section9of the rotor shaft1facing away from the rotor2and provided for receiving the inner ring4, the shoulder required for axially fixing the inner ring4is formed by a shaft nut9, which is tightened after the rolling bearing3has been mounted and therefore rests on the second end face8.2of the formed inner ring4.

In order to increase this axial rigidity of the rolling bearing3on the rotor shaft1and at the same time introduce axial forces at a flat angle from the shaft shoulder7into the inner ring4, the formed inner ring4not only has an axial length L3that corresponds to the axial length L2of the formed outer ring5, but is designed to be extended in both axial directions by sections10.1,10.2of length L4;4.1,4.2in relation to the outer ring5to which it is arranged, wherein the section10.1extends with the greater axial length L4.1in the direction of the rotor2. Consequently, the circumferential section1.1of the rotor shaft1, which receives the inner ring4between the shaft shoulder7and the shaft nut8, has a length L1, i.e., L3plus L4.1plus L4.2and is therefore completely filled by the inner ring4.

In order to also fix the inner ring4formed from the two half-shells4.1,4.2radially on the rotor shaft1, clamping rings11are provided. Each of these clamping rings11is formed by two half-shell-shaped clamping ring segments11.1,11.2which complement each other to form a ring, of which only one clamping ring segment11.1is visible in the selected representation inFIG.1. Since the respective clamping ring segments11.1(11.2), which form a clamping ring11, about one another at 6 o'clock and 12 o'clock, the circumferential end surfaces12of the clamping ring segments11.1are also shown inFIG.1.

In order to axially fix the clamping rings11formed on the inner ring4, the clamping rings11or the clamping ring segments11.1(11.2) have radially inwardly pointing projections13which, after assembly, engage in annular grooves14provided in the area of sections10.1,10.2on the inner ring4. In order to improve the tightness between the inner ring4and the clamping rings11, seals20.2in the form of O-rings are provided between the clamping rings11and the inner ring4.

Bores15are guided through the respective clamping ring segments11.1(11.2), which, in the connected state, form a clamping ring11, which—as shown for the half-shell11.1—extend perpendicular to the paper plane. Countersunk screws16are screwed in through these bores15in order to connect the two clamping ring segments11.1(11.2) to form a clamping ring11.

If the respective clamping ring segments11.1,11.2are assembled to form a clamping ring11on the inner ring4, an outer, annular circumferential surface17is created, which, in this exemplary embodiment, is in sealing contact as a sealing surface18with a sealing lip19of a contacting seal20.1acting as a sealing partner. In order to prevent the sealing lip19from wearing out because it comes into contact with the bores15, the sealing surface18begins at the axially outer end21of the clamping ring11and ends where the bores15of diameter D penetrate the clamping rings11. In relation to the bore15, this means that the part of the circumferential surface17which serves as a sealing surface18has a greater axial extent than the circumferential surface on the other side of the bore15. To better illustrate the relationships, the sealing surface18, which begins at the axial end21of the clamping ring11and ends at the diameter D of the bore15, is drawn to be bolder inFIG.1.

InFIG.2A, two clamping ring segments11.1,11.2forming a clamping ring11are shown in detail. Both clamping ring segments11.1,11.2are connected by a screw16which is screwed through bores15provided in the clamping ring segments11.1,11.2. If the two clamping ring segments11.1,11.2are finally assembled by tightening the screw16on the inner ring4, a small distance A remains between the end surfaces12of the two clamping ring segments11.1,11.2in order to produce the required clamping effect. In this exemplary embodiment, this distance A is filled with a plastic material based on epoxy resin so that the circumferential surface17of the clamping ring segment11.1merges seamlessly into the circumferential surface17of the other clamping ring segment11.2while maintaining the radius of curvature R1specified by the clamping ring segments11.1,11.2.

FIG.2Bshows a plan view of the transition between two clamping ring segments11.1,11.2according toFIG.2A. This representation also shows that the circumferential surface17expands to different extents in the axial direction in relation to the bore15and that the area with the greater axial extent serves as the sealing surface18.

The embodiment according toFIG.3only differs from the embodiment according toFIG.1in that the seal shown there is not a contacting seal20.1, but a non-contacting seal20.3. This non-contacting seal20.3is essentially formed by the mounted clamping rings11and a component24which is connected to the housing25. Thereby, both the outer circumferential surface17and also the axial outer end surface21of the clamping ring11form a common, angularly extending sealing surface18.1, which interacts with a corresponding sealing surface18.2that maintains a small distance from the sealing surface18.1and is provided by the component24. In order to further improve the sealing effect of this non-contacting seal20.3, the clamping rings11in the area of their end surfaces12also have ring noses26which are directed axially outward and which engage corresponding recesses27in component24.

FIG.4shows a variant of a rotor bearing according toFIG.1. In this variant, the respective bearing rings4,5are connected to the rotor shaft1as unsplit bearing rings4,5. Therefore, in this variant, no clamping rings11are required. In order to produce a seal of this variant by a contacting seal20.1, the sealing lips19run on sealing surfaces18provided by the inner ring4in the area of the sections10.1,10.2. Of course, a variant according toFIG.4can also be provided with a non-contacting seal20.3in a simple development of the explanations relating toFIG.3.

The variant shown inFIG.5shows a two-row spherical roller bearing as rolling bearing3, in which the rolling bodies6roll in both roller rows at the same pressure angle α, β.

FIG.6shows the transition28between two half-shells5.1,5.2, forming an outer ring5of a rolling bearing3according to the embodiment according toFIG.1. This view, which runs in the direction of the rotational axis DA of the rolling bearing3, shows a raceway29on the outer ring5(5.1,5.2) on which the rolling bodies6roll. Except for the transition28between two half-shells5.1,5.2, the raceway29in the outer ring5or in the half-shells5.1,5.2is circular, which is indicated by the radius R2. The raceway29only extends as a secant in the area of the transition28between the two points P1and P2.

Even if the rolling bearing3is always shown as a spherical roller bearing in the exemplary embodiments, there is no definition of this type of bearing. It is also not necessary for the rotor shaft1to be of a wind turbine. For example, instead of the rotor shaft, other machine shafts can also be supported by the rolling bearings shown, for example where it is very difficult to remove the entire machine shaft to replace rolling bearings3.