DK201600068A1 - RENTAL AND GEAR SETTING FOR A WINDMILL - Google Patents

Abstract

The economic efficiency of wind turbines is improved by upscaling while reducing weight to strength ratio. This is especially true of the large bearing roller bearing of the rotor, the gear and the generator. Solutions to this have been gearless generators which then become heavy as the amount of magnetic material is inversely proportional to the rpm; or several smaller generators adapted to the wind on a distribution gear as shown in (1), (2) and (3). The large roller bearing of the rotor gets a relatively large bearing veil so that only the upper or exclusive lower rollers carry all the weight of the rotor and thus have to be dimensioned relatively large. The present invention distributes the loads to multiple rollers and fast-running lighter generators. It has the rotor attached to the outer ring, each roller bearing bearing to the nacelle and the inner ring free-running. The outer and inner rings are relatively stiffer than the roller bearing to the nacelle, so that the upper rollers bend slightly below the weight of the rotor so that some of the gravity is transferred to the inner ring and further to the lower relatively rigidly mounted rollers. A tooth can transmit torque to all rollers or the inner ring can be pressed out against the middle rollers, or the tapered rollers can be dynamically pressed in between outer and inner ring with relatively constant compressive force. It is shown in Figures 1 and 6 in 3D illumination and Figure 2 and Figure 3 in radial section. Hereby, the shafts of these relatively small rollers can be used as geared power take-off in the bearing diameter to roller diameter ratio. The cost of the extra bearing of each roller is offset by the savings of the usual center shaft and gear. Also, the increased friction of a prestressed blurless bearing is offset by the lack of the usual extruding edge friction on the large rollers. These advantages are especially important for wind turbines where the hub shaft and gear are otherwise heavy components high up; and bearing blades provide inappropriate vibrations of the long components. Without hub, gear and generator ...

Description

RENTAL AND GEAR SETUP FOR A WINDMILL BACKGROUND OF THE INVENTION

At the same time as the wind turbine's upscaling to MW class, the weight of the nacelle has gone from about twice the rotor to the 3-4 double. Because the mass forces in the third power of the wing length dominate over the wind power in the second power thereof. The relatively large components of the nacelle that are to absorb these forces also have poorer weight compared to power utilization. For example, the large massive hub shaft weighs a great deal in the third potency of its radius while the forces are preferably absorbed into its surface in the second potency thereof. The same applies to the large central input gear, which also preferably absorbs forces in its periphery resulting in wastage of its central mass. There is thus the possibility of saving some mass, which in the prior art is simply there, and is not used for absorbing forces, and which, with round numbers, constitute a quarter of the nacelle weight. The object of the present invention is therefore to save about half of said non-absorbing mass, ie about 10% of the weight of the nacelle. A perhaps not so large number, but it may be of considerable importance to move the tower-nacelle intrinsic frequency above the excitation from the wings.

PRIOR ART

Gearless wind turbines with multi-pole generator on the large hub shaft are known techniques. The complexity of many poles and a large heavy amount of magnetic material is necessary to compensate for the low rpm; but the weight and complexity of the central gear are saved.

SUMMARY OF THE INVENTION

The bearing and gear unit according to the invention also saves the central hub shaft, since the power take-off from the only remaining bearing single rollers provides that which corresponds to the first stage gearing. Here it is natural to put many relatively small series-made generators on the shaft of each roller, thus obtaining the many poles relatively inexpensively. If the bearings 6 and 7 of the drawings 1 to 6 for the roller shaft are firmly anchored to the machine cabin, the upper must be able to carry the entire weight of the blade rotor attached to the outer ring 2. Otherwise, a freely counter-rotating inner ring as shown in Figure 6 can transfer half the weight to the lower rollers, when the rollers are mounted with a less spring stiffness relative to the machine cabin than the stiffness of the inner ring. Alternatively, a fixedly mounted inner ring can carry the entire rotor weight so that the bearings 6 and 7 of the intermediate ring of Figure 1 only withstand the usual extruding friction from the tapered rollers. A disadvantage, however, is that the current must then be transmitted via slip rings, because the bearing intermediate rings rotate at half speed and the gearing also becomes half of the aforementioned alternatives.

Furthermore, the problem of uneven transfer of force from rotor weight and friction force to rollers below the upper can be mitigated by their resilient travel in the axial direction pushing them more into the gap between inner and outer ring in positions below the upper. And diminished even more if it is an active walk controlled by actuators. The cost of these is offset by longer bearing life from more uniform load, smaller bearing veil and higher performance due to the lower bearing friction which can be dynamically lowered at the more frequent low wind speeds, where the requirements for the bearing's absorption of the wind forces are less. Under these conditions, the friction will be at least if the lower rollers are not pressed in between the rings and thereby also not get frictional force transferred to the lower generators or motors, so that they are best decoupled in transmission. The fact that the top rollers are compressed the most and thereby rotate the fastest with the greatest frictional force fits roughly with the usual variable electrical characteristic.

The changing forces of the wind can be absorbed by having opposite pairs of rollers clamping against the inner ring center from each side.

One embodiment has generators mounted on the shafts of the individual rollers outside the intermediate rings as shown in Figure 3, so that this bearing and gear unit replaces the usual hub shaft with associated bearings, central gear and generator in wind turbines. For a 7 MW turbine, this requires a 0 15 m blade rotor bearing to ensure that the friction against the rollers alone is sufficient to transmit the total torque. In another embodiment, the outermost tapered end of the rollers is provided with teeth corresponding to planetary gears so that the friction is not a limiting factor, whereby the bearing diameter can come down to 8 m. A third embodiment shown in figure 3 has another planetary gear after this, and the permanent magnet generators are displaced. Figure 5 shows one another, whereby the rotor bearing diameter can come down to 5m. However, as shown in Appendix 2, the smaller rollers cause the friction loss to increase from about 8% for the large 0 15m bearing to 9% and 10% respectively for the smaller ones.

The toothing can also be on the individual rollers with gears between the rollers to transfer the power to a central generator shown in Figure 6. As the wind increases, the necessary increased frictional force is obtained by pressing the outer ring against the rollers' sufficiently small cone angle, as calculated in Appendix 2. and the teeth of the gears may be successively wider towards the central 11, so that load becomes equal and weight at least.

A fourth embodiment has motors mounted on the shafts of the individual rollers outside the intermediate rings with spring or actuator biased bearings, so that this bearing and gear unit replaces the crank or wing turn ring with associated motors and brakes in wind turbines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the bearing and gear unit in 3D perspective.

FIG. 2 is a section of 1 showing the rollers and their bearing in detail.

FIG. 3 expands FIG. 2 with another gear stage and generator.

FIG. 4 is an even more detailed rotationally symmetrical view of FIG. 3 FIG. Figure 5 shows tight packing of gear and generator units offset to each other. FIG. 6 shows rollers and gears supported by a free-running inner ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGURE 1 of the drawing shows the bearing-gear generator construction in 3D lighting. 1 and 2 are the inner ring and outer ring, respectively, where 1 for a 7MW mill has the distance two and a half meters to the center of the bearing in the wind direction. 4 is the intermediate ring to which the rollers 5 are secured with the bearings 6 and 7.

Figure 2 is the corresponding radial section through A-A, where also a portion of the supporting connection 3 between the two opposite intermediate ring portions 4 is shown behind the shown roller 5.

In Figure 3, the connection 3 is designed as a central intermediate ring collector to which the intermediate ring shafts 4 of the opposite roller gear generator units 20 are rigidly attached.

Figure 4 shows a rotationally symmetrical section through two opposing roller gear generator units 20 through their axis of symmetry 19, denoting their components. The axial roller bearing 7 provides the necessary back pressure for the tapered roller 5, which rests at the bottom of another roller bearing 6. Without this continued roller with the same shading, the planetary gear 8 can rotate slightly relative to 5. The planetary gear 8 engages teeth on the outer ring 2 and possibly also the inner ring 1 (which corresponds to a sun wheel) and has the same tapered engagement circle as the tapered roller 5. At ideal fabrication accuracy, the very slow rotating fit between 5 and 8 would not be needed. shaft extension because they would rotate at the same speed.

The teeth are really only needed for a 7MW mill when the inner ring diameter, which is below 15 meters, which otherwise allows the transfer of the total torque with a traction oil with a coefficient of friction of 0.1 shown in Appendix 1.

From the planetary wheel 8, one or more shafts 9 of the next gear stage's planetary wheel 10 are engaged which engage the gear on the outer ring 16 and the sun gear 11. This is mounted in a needle bearing 13 just below the planetary wheel and a ball bearing 12 at the other end. Fixed to the sun gear 11 is the generator rotor 14, while the stator 15 is attached to the outer shade 16, one end of which is rigidly attached to the roller shaft 4 while the other is supported radially with a bearing 17 against the sun gear shaft 11.

The outer screen 16, which may rotates at half speed of the outer ring 2 with respect to both outer and inner rings ending up against these with, for example, a maze seal 18, which enables an oil bath around the planet wheels 10 and 8. An additional oil reservoir can be established in the outer ring 2 or behind the bearings 7 and 12.

In the design in which the outer screen with stator rotates i.f.t the inner ring, it is necessary to transmit the effect from here by means of a stator. slip rings. However, slip rings on one side of the wing rotor bearing can be satisfied by passing the current from the other side's generators through the hollow roller shafts 4.

Each of the 72 MW 72 kilowatt roller, gear and generator units 20 for a 7 MW turbine can be manufactured and assembled as standalone units. These units are mounted between free-hanging outer 2 and inner ring 1 by fastening their roller holder shaft 4 from the middle ring holder 3 from both sides. Thereby a predefined bearing veil can be established and possibly re-established by tension after bearing wear. The extra wear and tear from the edges of the hollow plug for inserting rollers into conventional large bend bearings is avoided, as well as the wear from the friction of conventional roll ends to the pressing or outer ring of the outer ring.

Figure 5 shows in section B-B of Figure 1 how a shorter embodiment of the roller, gear and generator unit 21 can be mounted in the narrowing of the outer shield 16 for 20 with less distance between them and thus more compact design.

To accommodate 36 generators for a 7 MW turbine on one side of a 0 5m wing rotor bearing, it is necessary to make this narrowing of the outer shield between the numbers 16 and 17 so that every other generator sits closer to the wing rotor bearing and fits into this notch.

Figure 6 shows how a free-flowing inner ring 1 transfers the forces from the outer ring 2 of the upper rollers 5a to the lower 8a. The inner ring only supports the rollers for which increased wind from the right increases the force, and they are mounted rotatably relative to the nacelle in bearings on both sides of the inner ring in positions 6 and 7. There are only bearing rollers on the upper and lower quarter respectively and they transmit the rotational force. to one another via mounted sprocket 9 to intermediate sprocket 10 to the central upper and lower sprocket 11. The last two can then transmit the applied torque via two vertical shafts 12 to a central angular gear 13 on a central generator 14. rollers are not shown but are mounted like rollers 5 of Figure 1 in four evenly spaced positions on the right inner conical surface of outer ring 15.

Claims (10)

Claim 1: Bearing and gear assembly for a wind turbine consisting of an outer ring mounted on the rotor and a number of rollers connected to the generator or motor characterized in that the rolling elements are rotatably fixed to the nacelle and carry the outer ring KRAV 2: Bearing and gear assembly for a wind turbine according to claim 1, characterized in that the upper rollers are mounted inside the outer ring, while the lower ones are mounted on the outside and thus carry some of the outer ring with rotor from the outside. REQUIREMENTS 3: Bearing and gear assembly for a wind turbine according to claim 1 or 2, characterized in that the rolling elements are supported by an inner ring from the inside. REQUIREMENTS 4: Bearing and gear assembly for a wind turbine according to claim 1, 2 or 3, characterized in that the rolling elements are attached to the nacelle with varying stiffness. REQUIREMENTS 5: Bearing and gear assembly for a wind turbine consisting of an outer ring mounted on the rotor and a number of rollers connected to the generator or motor characterized in that the rolling elements are rotatably fixed to a common intermediate ring for all the rollers rotating at half speed of the outer ring about a inner ring attached to the nacelle. REQUIREMENTS 6: Bearing and gear assembly for a wind turbine according to claim 5, characterized in that the rolling elements are secured via an actuator which moves the rollers in the direction of their axis of rotation towards the center plane of the outer ring. REQUIREMENTS 7: Bearing and gear assembly for a wind turbine according to claim 1, 2 or 3, characterized in that several rolling elements are connected to the same generator or motor and the asymmetrical torque of the wind is taken up by another bearing on the axis of symmetry of the outer ring. REQUIREMENTS 8: Bearing and gear assembly for a wind turbine according to claims 1,2, 3 or 4, characterized in that several rolling elements are connected to the same generator or motor and the bending moments of the wind are taken up by other angled rolling elements against the outer ring. REQUIREMENTS 9: Bearing and gear assembly for a wind turbine according to claim 1 or 5, characterized in that the generator or motor is mounted offset on successive rollers as shown in Figure 5. REQUIREMENTS 10: Bearing and gear assembly for a wind turbine according to claim 1 or 5, characterized in that the first-stage gear wheel for a single rolling element is movable in relation to the shaft of the rolling element.