Abstract
A planetary transmission for a wind turbine driven by a rotor includes a transmission housing, and a first planetary stage provided in the transmission housing about an axis of rotation. The first planetary stage includes a sun gear, a planet carrier and a ring gear. The planet carrier is designed at least indirectly to be drivingly connected to the rotor and includes a plurality of planet gears which revolve with the planet carrier and alternately mesh with the ring gear and the sun gear. A second planetary stage is provided in the transmission housing about the axis of rotation. A bearing is arranged within the sun gear and axially supports and mounts the sun gear in relation to the planet carrier of the first planetary stage such that the sun gear is rotatable about the axis of rotation.
Claims
1.-16. (canceled)
17. A planetary transmission for a wind turbine driven by a rotor, the planetary transmission comprising: a transmission housing; a first planetary stage provided in the transmission housing about an axis of rotation, said first planetary stage comprising a sun gear, a planet carrier and a ring gear, said planet carrier being designed at least indirectly to be drivingly connected to the rotor and comprising a plurality of planet gears which revolve with the planet carrier and alternately mesh with the ring gear and the sun gear; a second planetary stage provided in the transmission housing about the axis of rotation; and a bearing arranged within the sun gear and axially supporting and mounting the sun gear in relation to the planet carrier of the first planetary stage such that the sun gear is rotatable about the axis of rotation.
18. The planetary transmission of claim 17, wherein the planet gears alternately mesh with the ring gear and the sun gear via a helically toothing, the toothing having a right-hand or left-hand direction of a helix.
19. The planetary transmission of claim 17, wherein the planet carrier comprises an axially directed bearing flange, said sun gear being mounted at least indirectly on the bearing flange of the planet carrier.
20. The planetary transmission of claim 19, wherein the bearing flange is formed integrally with the planet carrier or is embodied as an annular component connected to the planet carrier to form with the planet carrier a functional unit.
21. The planetary transmission of claim 17, wherein the planet carrier of the second planetary stage is connected to the sun gear of the first planetary stage for conjoint rotation and in an axially supported manner.
22. The planetary transmission of claim 19, wherein the second planetary stage comprises a planet carrier which includes a hub, said bearing being designed as a rolling bearing assembly arranged in an axial region formed by an axially overlapping arrangement of the bearing flange of the planet carrier of the first planetary stage with the hub of the planet carrier of the second planetary stage.
23. The planetary transmission of claim 22, wherein the sun gear of the first planetary stage is held circumferentially on the hub of the planet carrier of the second planetary stage via a pair of toothings for conjoint rotation.
24. The planetary transmission of claim 17, wherein the second planetary stage comprises a planet carrier, said sun gear of the first planetary stage being screwed in an axial direction in relation to the planet carrier of the second planetary stage.
25. The planetary transmission of claim 17, wherein the second planetary stage comprises a planet carrier, the planetary transmission further comprising a bearing assembly designed to rotatably mount the planet carrier of the second planetary stage in relation to the transmission housing on a side facing away from the first planetary stage.
26. The planetary transmission of claim 22, wherein the second planetary stage comprises a planet carrier, said planet carrier of the second planetary stage designed to have a support on one side.
27. A powertrain for a wind turbine for a torque-transmitting connection of a rotor to a generator, the powertrain comprising: a main bearing unit comprising a bearing housing and a main shaft; and a transmission driven by the main shaft and driving the generator at least indirectly, said transmission being designed as the planetary transmission of claim 17.
28. A wind turbine, comprising: a rotor flange comprising a rotor; a generator; a machine support; and a powertrain held on the machine support and designed to connect the rotor flange to the generator, said powertrain comprising a main bearing unit comprising a bearing housing and a main shaft, and a transmission driven by the main shaft and driving the generator at least indirectly, said transmission being designed as the planetary transmission of claim 17.
Description
[0023] Below, the invention will be explained by way of example with reference to the appended drawings on the basis of preferred exemplary embodiments, wherein the features presented below may in each case individually or in combination represent an aspect of the invention. It is shown in:
[0024] FIG. 1: a schematic illustration of a wind turbine,
[0025] FIG. 2: a transmission designed as a planetary transmission for a wind turbine,
[0026] FIG. 3: cutout of a planetary transmission in a possible embodiment with a rotating-in-rotating bearing assembly;
[0027] FIG. 4: a cutout of a planetary transmission in a possible embodiment with a rotating-in-rotating bearing assembly;
[0028] FIG. 5: a cutout of a planetary transmission in a possible embodiment with a rotating-in-rotating bearing assembly, and
[0029] FIG. 6a)-6c): show axial forces generated by the helical toothing of the first planetary stage.
[0030] FIG. 1 shows, in a schematic illustration which is not true to scale, a wind turbine 100 in one possible embodiment. A substantial element of the wind turbine 100 is a powertrain 102, which in the present case structurally comprises a rotor flange 104 with a rotor 106, a main bearing unit 108, a transmission 10 and a generator 112. By way of a machine support 114, at least the main bearing unit 108 and the generator 112 are supported relative to the ground, which is not Illustrated, by way of a tower 116. The main bearing unit 108 comprises a main shaft 118 which is mounted by a positioned tapered rolling bearing assembly so as to be rotatable about an axis of rotation A.sub.D relative to a bearing housing 120 of the main bearing unit 108. The rotor flange 104 is held at one end of the main shaft 118 and the rotor 106 is held on the former. The other end of the main shaft 118 is connected here rigidly in terms of drive to the transmission 10 in order to Introduce into the transmission 10 a drive torque applied by the rotor 106. The transmission 10 can be embodied as a planetary transmission with one or more planetary stages. The transmission 10 is connected in terms of drive to the generator 112 by a generator shaft 124. The bearing housing 120 is connected to the transmission 10 via a flange 126. A reaction moment of the transmission 10 is supported with respect to the machine support 114 via the flange 126.
[0031] FIG. 2 shows a transmission designed as a planetary transmission 10, as can be installed, for example, in a wind turbine 100 shown in FIG. 1. The planetary transmission 10 comprises three serially arranged planetary stages 14.sub.1 to 14.sub.3 which are arranged so as to revolve about an axis of rotation A.sub.D in a transmission housing 12. Each planetary stage 14.sub.1 to 14.sub.3, apart from its dimensioning, is constructed accordingly and comprises a planet carrier 16, a ring gear 20, a sun gear 22 and a plurality of planet gears 18 which revolve with the planet carrier 16 and alternately mesh with the ring gear 20 and the sun gear 22 in a helically toothed manner. A feature of the design of the planetary transmission 10 is that each of the sun gears 22 is connected to the planet carrier 16 of the subsequent planetary stage 14 for conjoint rotation and fixed against displacement axially. A further feature of the design is that the planet carriers 16.sub.2 and 16.sub.3 of the second and third planetary stages 14.sub.2 and 14.sub.3 are each supported via bearings 24 on housing-side support flanges 26. Three support flanges 26.sub.1 to 26.sub.3 are provided, of which the first two are each arranged between the planetary stages 14.sub.1 to 14.sub.3 and one on the output side of the third planetary stage 14.sub.3. During the reversing operation, the axial force of the second planetary stage 14.sub.2 is supported via the first support flange 26.sub.1and the bearing 24, and the axial force of the third planetary stage 14.sub.3 is supported via the second support flange 26.sub.2 and the radially inner bearing 24. During the nominal operation, the axial force of the second planetary stage 14.sub.2 is supported via the second support flange 26.sub.2 and the radially outer bearing 24, and the axial force of the third planetary stage 14.sub.3 is supported via the third support flange 26.sub.3 and the bearing 24.
[0032] FIG. 3 shows a cutout of a planetary transmission 10 in a possible embodiment with a rotating-in-rotating bearing assembly of the sun gear 22 relative to the planet carrier 16.sub.1 in the first planetary stage 14.sub.1. The sun gear 22 is rotatably and axially supported on an axially directed bearing flange 28 of the planet carrier 16.sub.1 via a rolling bearing 30. It can be seen that the bearing flange 28 is connected as a separate annular component and in a suitable manner to the planet carrier 16.sub.1, for example via a plurality of circumferentially distributed and axially extending screw joints. Alternatively, the bearing flange 28 may also be formed integrally with the planet carrier 16.sub.1, which is not shown here.
[0033] The planet carrier 16.sub.2 of the second planetary stage 14.sub.2 is also mounted so as to be rotatable and supported via the rolling bearing 30 relative to the planet carrier 16.sub.1 of the first planetary stage 14.sub.1, specifically in this case indirectly via the sun gear 22 of the first planetary stage 14.sub.1. For this purpose, the sun gear 22 of the first planetary stage 14.sub.1 has an axial width which extends beyond the toothing region common to the planet gear 18, and therefore, because of this, the sun gear 22 may also be referred to as a sun shaft. The sun gear 22 of the first planetary stage 14.sub.1 is held internally circumferentially via a pair of toothings on a hub 32 of the second planet carrier 16.sub.2 for conjoint rotation. The sun gear 22 of the first planetary stage 14.sub.1 may be fixed in a suitable manner in the axial direction in relation to the hub 32, for example via a screw joint, which is not shown here.
[0034] FIG. 4 shows a cutout of a planetary transmission 10 in a further possible embodiment with a rotating-in-rotating bearing assembly of the sun gear 22 relative to the planet carrier 16.sub.1 in the first planetary stage 14.sub.1, The arrangement of the rolling bearing 30 is made in such a way that it is arranged in an axial region 34 formed by an axially overlapping arrangement of the bearing flange 28 of the planet carrier 16.sub.1 of the first planetary stage 14.sub.1 with the hub 32 of the planet carrier 16.sub.1 of the second planetary stage 14.sub.2. For this purpose, the bearing flange 28 of the planet carrier 16.sub.1 of the first planetary stage 14.sub.1 has been extended in the axial direction. The hub 32 of the planet carrier 16.sub.2 of the second planetary stage 14.sub.2 protrudes in the opposite axial direction in the first planetary stage 14.sub.1 and forms the overlapping axial region 34 with the extended bearing flange 28.
[0035] FIG. 5 shows a cutout of a planetary transmission 10 in a further possible embodiment with a rotating-in-rotating bearing assembly of the sun gear 22 relative to the planet carrier 16.sub.1 in the first planetary stage 14.sub.1. A second rolling bearing assembly 36 is provided, via which the second planet carrier 16.sub.1 is rotatably mounted in relation to the transmission housing 12 on the side facing away from the first planetary stage 14.sub.1. A shaft-hub connection is referred to by reference sign 38, wherein this comprises an expanding element sitting within the sun gear 22, for acting upon the sun gear 22 radially outward against the second planet carrier 16.sub.2. The spreading element can be of multi-part design and can have a toroidal core and a wedge ring sitting between the toroidal core and the sun gear 22 and acted upon in the axial direction.
[0036] With reference to FIG. 6 and the illustrations a), b) and c) thereof, the first planetary stage 14.sub.1 is used to explain how the axial force F generated via the helical toothing acts. First of all, illustration a) shows the ratios corresponding to the design of the planetary transmission 10 described in FIG. 2. The helical toothing causes the production at the planet gears 18 and the planet carrier 16.sub.1 of the axial forces F.sub.P1 and F.sub.P2, which act in opposite directions, so that F.sub.P1F.sub.P2=0. The planet carrier 161 is therefore force-free. The axial force FH arising at the ring gear 20 is absorbed and supported by the housing 12. The axial force F.sub.S arising at the sun gear 22 counteracts the axial force F.sub.H with respect to the direction and is absorbed by the planet carrier 16.sub.2 and, as described above, is supported by a support flange 26 with a bearing assembly 24. The support flange and bearing assembly are not shown here for the sake of clarity. As a result of the fact that the axial force F.sub.S arising at the sun gear 22 is diverted via the second planetary stage 14.sub.2 and the support flange 26 into the housing 12, the requirements already described above regarding installation space and component strength arise.
[0037] The ratios shown in illustrations b) and c) of FIG. 6 correspond to the embodiment of the planetary transmission 10 described in FIGS. 3 and 4, with the decisive difference that, between the illustrations b) and c) of FIG. 6, the direction of the helix of the helical toothings in the planetary stage 16 is reversed. Illustration b) is based on a right-hand or left-hand direction of the helix, which can be referred to as conventional, and illustration c) is based on a reversed left-hand or right-hand direction of the helix. As a result of the reversed direction of the helix, the individual axial forces that are effective on the respective toothing element are in each case opposed between illustrations b) and c). Furthermore, as a result of the rotating-in-rotating bearing assembly of the sun gear 22 on the planet carrier 16, the axial force F.sub.S arising on the sun gear 22 is introduced into the planet carrier 16 via the rolling bearing 30. Since the axial force F.sub.P2 of the planet gear 18 is also introduced into the planet carrier 16, F.sub.SF.sub.P2=0, so that this subsystem is force-free. Furthermore, the axial force F.sub.H of the ring gear 20 is absorbed and supported by the housing 12. Consequently, because of the axial force F.sub.P1 of the planet gear 18, the planet carrier 16 is not force-free, and the axial force F.sub.P1 is supported by the main bearing unit 108, as has already been described above. The difference between the ratios of the two illustrations b) and c) is that the main bearing unit 108 is acted upon by the axial force F.sub.P1 in respectively opposite directions. Given the ratios of illustration c), the axial force F.sub.P1 counteracts the wind forces, which act on the main bearing unit 108, of the rotor 106, so that the axial force F.sub.P1 relieves the main bearing unit of load.
LIST OF REFERENCE SIGNS
[0038] 10 Planetary transmission [0039] 12 Transmission housing [0040] 14 Planetary stage [0041] 16 Planet carrier [0042] 18 Planet gears [0043] 20 Ring gear [0044] 22 Sun gear [0045] 24 Rolling bearing assembly [0046] 26 Support flange [0047] 28 Bearing flange [0048] 30 Rolling bearing [0049] 32 Hub [0050] 34 Axial region [0051] 36 Rolling bearing assembly [0052] 38 Shaft-hub connection [0053] 100 Wind turbine [0054] 102 Powertrain [0055] 104 Rotor flange [0056] 106 Multi-blade rotor [0057] 108 Main bearing unit [0058] 112 Generator [0059] 114 Machine support [0060] 116 Tower [0061] 118 Main shaft [0062] 120 Bearing housing [0063] 124 Generator shaft [0064] 126 Flange
