Wind turbine gearbox

Abstract

The invention relates to a wind turbine gearbox (1) having at least one gearwheel (2) which is mounted on an axle (5), wherein a bearing point with a plain bearing (4) is arranged between the gearwheel (2) and the axle (5), and wherein, in the axle (5), there is formed a recess for the supply of a lubricant to the plain bearing (4). In the region of a contact surface of the plain bearing (4), a groove (18) is formed in the gearwheel (2) or an intermediate space (7) is formed between the plain bearings (4), which groove or intermediate space is connected via at least one connecting line (16) to the surrounding atmosphere.

Claims

1. A wind turbine gearbox having at least one gearwheel, which is mounted on an axle, wherein a bearing point with a plain bearing is arranged between the gear-wheel and the axle, wherein in the axle a recess is formed for supplying a lubricant to the plain bearing, wherein in the region of a bearing surface of the plain bearing on the gearwheel a groove is formed in the gearwheel and the groove is connected via at least one connecting line to the surrounding atmosphere, and wherein the connecting line is formed in the axle.

2. The wind turbine gearbox as claimed in claim 1, wherein the axle is designed at least partly as a hollow axle.

3. The wind turbine gearbox as claimed in claim 1, wherein at least a portion of the lubricant can be removed from the plain bearing area via the connecting line in the axle.

4. The wind turbine gearbox as claimed in claim 1, wherein a ratio of a width of the bearing point in an axial direction to a diameter of the axle in a radial direction is a maximum of 2.

5. The wind turbine gearbox as claimed in claim 1, wherein a width of the groove in an axial direction is selected from a range of 5% to 90% of a width of the plain bearing in the axial direction.

6. The wind turbine gearbox as claimed in claim 1, wherein a height of the groove in a radial direction is selected from a range of 5% to 100% of a wall thickness of the plain bearing.

7. A wind turbine gearbox having at least one gearwheel, which is mounted on an axle, wherein a bearing point with plain bearings is arranged between the gear-wheel and the axle, which plain bearings are spaced apart from one another in an axial direction forming an intermediate space, wherein in the axle a recess is formed for supplying a lubricant to the plain bearings, wherein the intermediate space is connected to the surrounding atmosphere via at least one connecting line, wherein the connecting line is formed in the axle, and wherein in the region of each plain bearing at least one recess is provided for supplying the lubricant.

8. The wind turbine gearbox as claimed in claim 7, wherein a width of the intermediate space in the axial direction is selected from a range of 5% to 90% of a width of a plain bearing in the axial direction.

9. The wind turbine gearbox as claimed in claim 7, wherein a height of the intermediate space in a radial direction is selected from a range of 5% to 100% of a wall thickness of a plain bearing.

Description

(1) In a schematically much simplified representation:

(2) FIG. 1 shows a cross section of a section of a wind turbine gearbox;

(3) FIG. 2 shows a cross section of a section of an embodiment variant of the wind turbine gearbox.

(4) First of all, it should be noted that in the variously described exemplary embodiments the same parts have been given the same reference numerals and the same component names, whereby the disclosures contained throughout the entire description can be applied to the same parts with the same reference numerals and same component names. Also details relating to position used in the description, such as e.g. top, bottom, side etc. relate to the currently described and represented figure and in case of a change in position should be adjusted to the new position.

(5) FIG. 1 shows a cross section of a section of a wind turbine gearbox 1. The wind turbine gearbox 1 is designed in particular in the form of a (single) planetary gear.

(6) As already known, wind turbines comprise a tower with a gondola arranged at its upper end, in which the rotor with the rotor blades is mounted. The said rotor is operatively connected via a gearbox to a generator, which is also located in the gondola, wherein by means of the gearbox the low speed of the rotor is translated into a higher speed of the generator rotor. As such embodiments of wind turbines form part of the prior art, reference is made at this point to the relevant literature.

(7) The wind turbine gearbox 1 comprises at least one gearwheel 2. Said gearwheel 2 is arranged in the wind turbine gearbox 1 in meshing engagement between a second and a third gearwheel (both not shown). In addition, the at least one gearwheel 2 comprises an outer spur gearing 3.

(8) In the embodiment of the wind turbine gearbox 1 as a planetary gear, in particular as the main gearbox of a wind power plant, the second gearwheel is designed as a sun gear with a spur gearing, which is connected in a rotationally secure manner to a shaft which leads to the generator rotor. The sun gear is usually surrounded by a plurality of gear wheels 2, the planetary gears, for example two, preferably three or four.

(9) The third gearwheel is designed as a hollow gear which surrounds the at least one gearwheel 2 or the gear wheels 2 in radial direction and which on an inner surface also comprises at least partly a gearing which is meshing engagement with the outer spur gearing 3 of the gearwheel 2 or the gear wheels 2. The hollow gear is connected in a rotationally secure manner to a rotor shaft of the rotor of the wind turbine or is connected in a rotationally secure manner to the housing of the wind turbine gearbox 1.

(10) The toothings of the gear wheel in the wind turbine gearbox 1 can be configured to be straight or oblique.

(11) The at least one gearwheel 2 (in the following only one gearwheel 2 is described, wherein said embodiments can be applied to all or a plurality of gear wheels 2) is mounted by a plurality of plain bearings 4, in particular multi-layered plain bearings, on an axle 5, i.e. for example a planetary shaft (the so-called planetary axle). Said axle 5 can either be designed in one piece with at least a part of a gearwheel support 6, in particular a planet carrier, or it is inserted as a separate component into bores of the gearwheel support 6.

(12) It should be noted that it is possible to provide not only single stage embodiments of such wind turbine gearboxes 1 within the scope of the invention, but also multi-stage embodiments, for example two or three-stage mechanisms are possible, whereby additional spur gearing stages can be integrated into at least one gearwheel 2, in particular a planetary gear. In addition, parallel gearboxes, as described for example in the aforementioned EP 2 284 420 B1, are also possible within the scope of the invention. Reference is therefore made to this document, which in this regard is associated with the present description. Thus the wind turbine gearbox 1 can comprise a single planetary gear and a parallel two or multi-stage planetary gear or generally a plurality of planetary gears.

(13) Furthermore, it should also be mentioned that, although preferred, the invention is used not only in the planetary gears of wind turbines, but can be used generally in the gearboxes of wind turbines, in particular for translating the slow speed of the rotor of a wind turbine into a higher speed.

(14) The plain bearings 4 are arranged spaced apart from one another in axial direction forming an intermediate space 7.

(15) The plain bearings 4 can be designed in principle in the form of plain bearing half shells. Preferably however, the latter are in the form of bearing bushes. The bearing bush of a gearwheel 2 is connected in a rotationally secure manner to the latter, for example via a press-fit or by other suitable methods. Alternatively, it is possible for the plain bearing 2 to be connected in a rotationally secure manner to the axle 5.

(16) A multilayered plain bearing consists at least of a support layer and a plain layer which is applied onto the support layer. The plain layer thereby forms a running surface for the axle 5 or the gearwheel 2, according to the aforementioned arrangement.

(17) The multilayering of the plain bearing 4 can also be achieved in that the axle 5 is coated in the region of the bearing of the gearwheel 2 and/or the gearwheel 2 itself in the region of the bore mounting the axle 5 with a material for a plain layer. In this case the support layer of the multilayered plain bearing is formed by the material of the gearwheel 2, for example steel and/or the material of the axle 5, for example steel.

(18) In addition to this two-layered embodiment of the multi-layered plain bearing, it is also possible within the scope of the present invention that intermediate layers are arranged between the plain layer and the support layer, for example a bearing metal layer and/or at least one bonding layer and/or a diffusion barrier layer.

(19) Examples of materials for the individual layers of the multilayered plain bearing are described in the aforementioned AT 509 624 B1, which is referred to here and in this regard is associated with the present description.

(20) In axial direction in addition to a plain bearing 4 a run-on disc 8 can be provided between the plain bearings 4 or the gearwheel 2 and the gearwheel support 6.

(21) The sliding layer of the plain bearing 4 can be raised up into the end face to the run-on discs 8 so that the plain bearings 4 also perform an axial bearing function in addition to the radial bearing function.

(22) In addition, the gearwheel 2 can comprise at the end sides—as viewed in axial direction—peripheral annular grooves 9, in which the plain bearings 2 are arranged. An annular web 10 of the gear wheel 2 pointing in the direction of the axle 5 and arranged between the plain bearings 4 forms the upper boundary of the intermediate space 7. Alternatively, a spacing element can be arranged between the plain bearings 2 and above the intermediate space 7 which spacing element is connected in particular to the gearwheel 2.

(23) FIG. 1 also shows the supply of lubricant to the running surfaces of the plain bearing 4. In addition, by means of a bore 11 or a channel-like recess in the axle 5, lubricant, in particular lubricant oil, is supplied from a lubricant inlet 12, which is connected to a not shown lubricant reservoir, into areas 13 of the running surfaces of the plain bearings 4, from which the lubricant is distributed over at least almost the whole running surface. The bore 11 or the recess comprises a plurality of sections which have in particular either a radially outwardly pointing or axially running direction. Furthermore, a part of the bore 11 or the recess can also be guided by the gearwheel support 6, as shown in FIG. 1.

(24) The precise direction of the sections of the bore 11 or the recess corresponds to the mechanical requirements of the wind turbine gearbox 1 and/or to the ease of production.

(25) As shown in FIG. 1, the bore 11 or the recess comprises at least one branch in order to distribute the lubricant to all of the bearing points, so that each of the two plain bearings 4 has at least one separate lubricant supply—it should be mentioned that also more than two plain bearing (bushes) can be provided per gearwheel 2. If necessary a plurality of lubricant outlets 14 to the bearing point can be arranged distributed over the circumference of the plain bearing 4, for example two or three or four, etc. Alternatively or in addition, a plurality of lubricant outlets 14 can also be arranged behind one another in axial direction.

(26) It is also possible for the lubricant to be supplied from two sides—as viewed in axial direction—i.e. an additional lubricant inlet 15 being formed in the gearwheel support 6 or in the axle 5. For example, at least one lubricant inlet 15 can be arranged on the rotor side (in FIG. 1 left of the gearwheel 2) and on the generator side (in FIG. 1 right of the gearwheel 2), whereby a plurality of lubricant inlets 15 can also be arranged on at least one side (or on both sides).

(27) Unlike the embodiment of the lubricant supply shown in AT 509 624 B1 in the wind turbine gearbox 1 according to the invention the lubricant is not supplied to the intermediate space 7 delimited by the plain bearing 4, the axle 5 and the gearwheel 2, but underneath the plain bearing 2, as shown in FIG. 1. As described in the prior art the lubricant outlets 14 preferably end directly below the running surfaces 16 of the plain bearing 4.

(28) The axle 5 can comprise a recess in the supply area of the lubricant, i.e. a step in the section of the surface, in order to thus support the distribution of the lubricant. By means of this step a larger cross section of the lubricant outlet 14 is achieved.

(29) It should be mentioned in particular at this point that the supply of lubricant can also be performed exclusively via the axle 5, i.e. the gearwheel support 6 has no bore or channel-like recess for this.

(30) To improve the distribution of the lubricant over at least almost all of the running surfaces the intermediate space 7 is connected via at least one connecting line 16 to the surrounding atmosphere. Preferably, the connecting line 16 runs in the axle 5, whereby at least one radial section is formed below the intermediate space 7 which opens into an axial section in the axle 5. The latter runs in the direction of the longitudinal middle axis through the axle 5 into an axial end face of the shaft.

(31) As preferably the intermediate space 7 is designed to run over the whole circumference of the shaft, preferably also a plurality of radial sections of the connecting line 16 are formed, for example two as shown in FIG. 1, or three or four, etc.

(32) It is also possible that the axial section of the connecting line 16 runs in the area of the longitudinal center axis of the axle 5 so that the latter is thus designed at least partly as a hollow axle.

(33) According to one embodiment variant the axle 5 can be designed completely as a hollow axle so that the axial section of the connecting line 16 extends up to both end faces of the axle 5—as viewed in axial direction.

(34) Alternatively or in addition, at least one connecting line 16 can also be formed in the gearwheel 2, as shown by a dashed line in FIG. 1.

(35) It is also possible within the scope of the invention for a plurality of radial sections of the connecting line 16 to be arranged next to one another in axial direction below the intermediate space 7.

(36) The diameter of the radial sections of the connecting line 16 directly underneath the bearing points is preferably selected from a range of 5 mm to 30 mm, in particular from a range of 10 mm to 20 mm. Preferably, the total cross section of the connecting lines 16 is as large as the total cross section of the oil supply lines.

(37) Furthermore, the cross section of the connecting line 16 can be designed to be round, oval, rectangular, square or polygonal, etc.

(38) To remove the lubricant from the bearing areas independent removal lines can be provided (not shown). However, at least a portion of the lubricant can also be removed via the connecting line in the axle 5.

(39) It is also preferable, if the ratio of the width of the bearing point in axial direction to the diameter of the axle 5 in radial direction is a maximum of 2. In particular, said ratio can be selected from a range of 1 to 2, preferably from a range of 0.3 to 0.8.

(40) In addition, preferably the width 17 of the intermediate space 7 in axial direction is selected from a range of 5% to 90%, in particular from a range of 10% to 50%, of the width of a plain bearing 4 in axial direction.

(41) Furthermore, preferably the height 18 of the intermediate space 7 in radial direction is selected from a range of 5% to 100%, in particular from a range of 10% to 70%, of the wall thickness of the plain bearing 4.

(42) All of the dimensions of the ratios are in mm.

(43) It is also possible within the scope of the invention that the two or a plurality of plain bearings 4 are combined into a plain bearing 4, in particular only one plain bearing 4 is provided in the form of a plain bearing bush, as shown in FIG. 2.

(44) In this case the intermediate space 7 represented in FIG. 1 can be formed by at least one groove 18 in the bearing surface of the gearwheel 2. The at least one groove 18 runs in circumferential direction in the body of the gearwheel 2.

(45) Furthermore, said embodiment variant of the wind turbine gearbox 1 preferably corresponds to that of FIG. 1. In this embodiment variant the groove 18 is connected via at least one connecting line 16 to the surrounding atmosphere. The at least one connecting line 16 can be guided through the gearwheel 2 or—as shown by a dashed line in FIG. 2—through the plain bearing 4 and the axle 5, wherein both variants are possible in one embodiment of the wind turbine gearbox 1.

(46) Lastly, as a point of formality it should be noted that for a better understanding of the structure of the wind turbine gearbox 1 the latter and/or its components have not been represented to scale and/or have been enlarged and/or reduced in size.

LIST OF REFERENCE NUMERALS

(47) 1 wind turbine gearbox 2 gearwheel 3 outer spur gearing 4 plain bearing 5 axle 6 gearwheel support 7 intermediate space 8 run-on disc 9 annular groove 10 annular web 11 bore 12 lubricant inlet 13 section 14 lubricant outlet 15 lubricant inlet 16 connecting line 17 width 18 groove