Gearbox and method for operating a gearbox

Description

[0001] The invention relates to a gearbox or a method for operating a gearbox. The gearbox is, in particular, coupled to an electric machine. The electric machine is a motor or a generator. The gearbox is located, for example, in a large machine drive train for a wind turbine or a mill for, e.g., ores or cement.

[0002] Increased system integration of wind turbine gearboxes with the generator raises the demands on gearbox sealing. The seal between the pitch tube and the generator is particularly critical, as leaking oil can damage the generator.

[0003] In conventional gearbox designs, there is an axial space between each sun gear and the nearest rotor-side component. Oil is forced into this space from the meshing of the gear teeth and runs axially along the pitch tube, towards the generator, due to the gearbox inclination.

[0004] In integrated designs, the pitch tube can be radially supported within the generator. This eliminates the shielding effect of the bearing on the pitch tube, and the oil squeezed from the planetary gear teeth is directed directly to the generator seal.

[0005] In non-integrated designs, the axis of the pitch tube and generator is not coaxial. In this configuration, the pitch tube is supported within the gearbox housing. This support also serves as an oil containment element. The pitch tube is sealed to the outside, for example, by a simple labyrinth seal.

[0006] From EP 2 541 058 B1, a drive system is known which has a gear unit comprising at least one planetary gear stage. The planetary gear stage includes a ring gear, several planet gears, a planet carrier, and a sun gear. A pitch tube is arranged within an output shaft and a hollow rotor shaft, extending axially over the entire drive system.

[0007] From DE 10 2015 223 669 A1 a sealing concept for a rotary feedthrough of a gearbox of a wind turbine is known, in which a cover element is arranged on a planet carrier of a planet gear stage.

[0008] From US 2017 / 299044 A1, a differential gear for a motor vehicle is known in which a shaft of a bevel gear is passed through a sleeve and the sleeve has a deflector projecting radially outwards to distribute incoming lubricating oil to two bearings supporting the shaft.

[0009] US Patent 2015 / 104127 A1 discloses a spur gear transmission in which a shaft passes through a sleeve connected to a conical deflector, the deflector retaining lubricating oil in an oil chamber.

[0010] From WO 2011 / 055384 A2 a planetary gear is known with a carrier shaft of a planet carrier penetrating a sun gear, wherein the carrier shaft has a vent channel and a conical deflector attached to the carrier shaft, wherein the deflector is intended to prevent the ingress of lubricating oil into a radially extending space of the vent channel.

[0011] From DE 10 2019 207 102 A1, which forms the preamble of claim 1, a vertical gearbox for a wind turbine is known in which lubricant dripping from a splined connection between a sun shaft and a sun gear of a planetary stage falls into a collection tray and is discharged via a drain spaced apart from a pitch tube.

[0012] One object of the invention is to provide a protective system for deflecting squeeze oil to the pitch tube.

[0013] The problem is solved by a transmission having the features of claim 1, a use having the features of claim 11, and a method having the features of claim 12. Preferred embodiments are specified in the dependent claims and the following description, each of which, individually or in combination, can represent an aspect of the invention, the scope of protection being defined by the claims. When a feature is presented in combination with another feature, this serves only to simplify the presentation of the invention and is in no way intended to imply that this feature cannot also constitute a further development of the invention without the other feature.

[0014] One aspect of the invention relates to a gearbox for a wind turbine, comprising at least one first gearbox stage, wherein the gearbox has a feedthrough, wherein a first deflector is provided for deflecting a lubricant from the feedthrough, wherein the first gearbox stage comprises a planetary gearbox and the feedthrough is a pitch tube, wherein the first deflector is rigidly connected to a sun gear.

[0015] The gearbox is primarily horizontally oriented. It is intended for use in a wind turbine. In the designated installation position, the primarily horizontally oriented gearbox may be inclined slightly, i.e., by approximately 2° to 15°, particularly 3° to 10°, and most preferably 4° to 5°, to the horizontal. The at least one deflector is designed to prevent lubricant, particularly lubricating oil, from entering the feedthrough. For this purpose, at least part of the deflector may be positioned in a path between a lubricant outlet and the feedthrough. Without the deflector, lubricant could drip from the lubricant outlet onto the feedthrough in the direction of gravity due to a slight inclination of the gearbox to the horizontal.Since the deflector can be positioned in the direction of gravity between the lubricant outlet and the feedthrough, the gravity-driven dripping lubricant can be collected and drained away by the deflector. This utilizes the understanding that, with a slight inclination of the gearbox, as is particularly common in wind turbine applications, the surface tension of the lubricant may not be sufficient to prevent it from adhering to the components at the outlet and being drained away, as opposed to a purely horizontal orientation. Instead, gravity may cause the lubricant to detach and drip off.Unlike a purely vertically oriented gearbox, the lubricant does not drip past the feedthrough, but would, due to the angled direction of gravity used to align the feedthrough, hit the feedthrough without a deflector to prevent this.

[0016] In particular, a second deflector is provided to deflect the lubricant away from the bushing. The first deflector and the second deflector are preferably located at different axial ends of the transmission and / or at different axial ends of the at least one gear stage of the transmission. It is especially preferred that the first deflector is located at a first end of the bushing and the second deflector at a second end of the bushing that extends axially away from the first end. This prevents lubricant from penetrating the bushing through the openings provided at the axial ends.

[0017] Preferably, the first deflector and / or the second deflector is arranged at an end side of the gearbox and / or at an end side of a gearbox stage of the gearbox.

[0018] In one embodiment of the transmission, the transmission has at least one second transmission stage, wherein the first deflector and / or the second deflector is provided for deflecting lubricant between the first transmission stage and the second transmission stage.

[0019] In one embodiment of the gearbox, the second deflector is permanently connected to a sun gear.

[0020] In one embodiment of the gearbox, the first deflector and / or the second deflector has a circular arc shape.

[0021] In one embodiment of the gearbox, the first deflector and / or the second deflector has a groove.

[0022] In one embodiment of the gearbox, the first deflector and / or the second deflector provides compensation for an inclination of the gearbox.

[0023] In one embodiment of the gearbox, the first deflector and / or the second deflector projects into a circular recess, wherein the at least one deflector and the circular recess are arranged to be rotatable relative to each other.

[0024] In one embodiment of the transmission, the transmission in particular has an oil sump.

[0025] In one embodiment of the gearbox, the first deflector and / or the second deflector has an electrically insulating material.

[0026] The invention further relates to the use of a gearbox, which can be designed and further developed as described above, in an installation position inclined at an angle of 2° to 15° to a main axis of rotation of the gearbox, particularly in a wind turbine. A main axis of rotation is understood to be an axis of rotation of the gearbox corresponding to the axial direction, in particular an axis of rotation of a sun gear shaft connected to a sun gear.

[0027] The invention further relates to a wind turbine with a gearbox mounted at an angle of 2° to 15° to the horizontal, which can be designed and further developed as described above. The wind turbine can be designed and further developed as explained above with reference to the gearbox.

[0028] The invention further relates to a method for operating a gearbox, which can be designed and further developed as described above, wherein the first deflector and / or the second deflector deflects lubricant from the feedthrough. The method can be designed and further developed as explained above with reference to the gearbox.

[0029] In one embodiment of the process, the lubricant is squeeze oil.

[0030] In one embodiment of the process, lubricant rejected by the deflector is directed into an oil sump.

[0031] In one embodiment of the gearbox, the pitch tube can be mounted within the gearbox. The pitch tube is a feedthrough. No further sealing requirements arise.

[0032] In one embodiment of the method, the gearbox is connected to an electric machine, whereby the passage is kept free of lubricant.

[0033] The present invention is explained in more detail below by way of example with reference to the drawings. The drawings show: Figure 1 shows a gearbox in a sectional view, Figure 2 shows another gearbox in a sectional view, Figure 3 shows a section of the further gearbox, Figure 4 shows a further section of the further gearbox, and Figure 5 shows a third section of the further gearbox.

[0034] The representation according Figure 1 Figure 1 shows a gearbox 1 with gear stages 2, 3, and 4. The gearbox 1 has end faces 16 and 17. A passage 13, also called a pitch tube, runs through the gearbox 1. The axis 20 of the pitch tube has an inclination 22 to a horizontal 21. The gear stages 2 have a ring gear 5, planetary gears 6, and sun gears 7. There are cavities, an axial space LSS 8 and an axial space IMS 9. Squeeze oil enters these spaces, as indicated by arrows 10.

[0035] The representation according Figure 2Figure 1 shows another gearbox with gear stages 2 and 3, in which a first shielding system 11 and a second shielding system 12 are provided. The shielding systems have deflectors 14 and 15. The deflectors deflect any squished oil. This ensures that the pitch tube remains free of squished oil. This results in an integrated protection system for deflecting squished oil to the pitch tube. In this system, there is a radially circumferential oil deflector between each sun and the nearest rotor-side component. This shield reduces the free space in front of the gear teeth. Thus, the majority of the oil is drained directly into the oil sump. The shield is designed so that there is axial overlap with the sun or the nearest axially located component. This prevents the oil from directly reaching the pitch tube. The shield can be screwed onto the sun or the nearest component, or it can be an integral part of the component or sun.Multiple shielding layers with different diameters are possible.

[0036] The illustration in Figure 3 shows a section of the further gearbox. The deflector 14 is fastened with screws 29. The deflector 14 has a channel 18 with a sloping channel base 24. This allows, for example, compensation for an inclined installation of the gearbox. The channel base 24 has an inclination 23 to the horizontal 21.

[0037] The representation according Figure 4 shows a further detailed representation of deflector 14. Here, a somewhat horizontal channel bottom is shown as an example.

[0038] The representation according Figure 5Figure 1 shows a further detail of the transmission. A second shielding system is depicted, located in an area between the sun gear 7 and the sun gear 7'. Here, too, oil can collect in a channel 31. The channel is located in a deflector 15. The deflector 15 has a rim 27 that projects between the sun gear 7' and the pitch tube 13. The deflector 15 also has a rim 32, which is at least partially located under an overhang 28 of the sun gear 7'. This allows squeezed oil to slide from the sun gear 7' over the overhang 28 and the rim 28 into the channel 31.

Claims

1. Transmission (1) having at least one first transmission stage (2, 3, 4), wherein the transmission (1) has a feedthrough (13), wherein a first deflector (14) is provided for deflecting a lubricant away from the feedthrough (13), wherein the transmission is provided for a wind turbine, the first transmission stage (2, 3, 4) has a planetary transmission, and the feedthrough (13) is a pitch tube, characterized in that the first deflector (14) is connected fixedly to a sun gear (7).

2. Transmission (1) according to Claim 1, wherein a second deflector (15) is provided for deflecting the lubricant away from the feedthrough (13).

3. Transmission (1) according to Claim 1 or 2, wherein the first deflector (14) and / or the second deflector (15) is / are arranged on an end side of the transmission (1).

4. Transmission (1) according to one of Claims 1 to 3, wherein the transmission (1) has at least one second transmission stage (2, 3, 4), wherein the first deflector (14) and / or the second deflector (15) is / are provided for deflecting lubricant between the first transmission stage (2) and the second transmission stage (3).

5. Transmission (1) according to one of Claims 2 to 4, wherein the second deflector (15) is connected fixedly to a sun gear (7).

6. Transmission (1) according to one of Claims 1 to 5, wherein the first deflector (14) and / or the second deflector (15) has / have a circular arc shape.

7. Transmission (1) according to one of Claims 1 to 6, wherein the first deflector (14) and / or the second deflector (15) has / have a channel (18, 19).

8. Transmission (1) according to one of Claims 1 to 7, wherein the first deflector (14) and / or the second deflector (15) projects / project into a circular-arc-shaped recess, wherein the at least one deflector (14, 15) and the circular recess are arranged rotatably with respect to each other.

9. Transmission (1) according to one of Claims 1 to 8, wherein the transmission (1) has an oil sump.

10. Transmission (1) according to one of Claims 1 to 9, wherein the first deflector (14) and / or the second deflector (15) has / have an electrically insulating material.

11. Use of a transmission (1) according to one of Claims 1 to 10 in an installation position in a wind turbine that is inclined by 2° to 15° with respect to a main axis of rotation of the transmission (1).

12. Method for operating a transmission (1) according to one of Claims 1 to 10, wherein the first deflector (14) or the first deflector (14) and the second deflector (15) deflects / deflect lubricant away from the feedthrough (13).

13. Method according to Claim 12, wherein lubricant deflected by the first deflector (14) and / or by the second deflector (15) is conducted into an oil sump.

14. Method according to Claim 12 or 13, wherein the transmission (1) is connected to an electric machine, wherein the feedthrough (13) is kept free from the lubricant.