SHAFT-HUB CONNECTION FOR A GEARBOX

Description

[0001] The invention relates to a shaft-hub connection for a planetary gear, comprising a shaft, a hub element connected to the shaft via a splined connection about a main axis of rotation AR and surrounding the shaft circumferentially, wherein a housing element fixed with respect to the main axis of rotation is provided and an oil channel opening in the area of ​​the splined connection runs in the housing element and the hub element in order to supply lubricating oil to at least the splined connection via the oil channel.

[0002] Planetary gearboxes, such as those used in wind turbine gearboxes, can include splined connections between two rotating components. Adequate lubrication of these metal-to-metal contacts is crucial to minimize wear. The indirect accessibility of the lubrication points and the centrifugal force generated by the rotating components make adequate lubrication via an oil spray system challenging. Previous solutions have involved injecting an oil jet into a gap in the gear pair between the shaft and hub elements. In a wind turbine gearbox, the shaft element is typically a sun gear shaft that transmits power to a hollow hub element of a spur gear stage. The spur gear stage is located on the generator side of the wind turbine gearbox and is therefore on the output side relative to the planetary gearbox.

[0003] Document CN 205446657 U shows a planetary gear unit in which lubricating oil is supplied on the output side via a housing element. The lubricating oil is introduced into the rotating hub element via the housing element. WO 2017 / 032558 A1 shows a planetary gear stage and a subsequent spur gear stage. Between the planetary gear stage and the spur gear stage, an oil channel extends radially inward from the radially outer housing to the splined connection. Document CN 113175520A also discloses a shaft-hub connection.

[0004] US 2016 / 223073 A1 shows an oil transfer from the generator-side support flange of the last planetary stage radially inwards into the hollow shaft, where the oil is directed to the splined shaft. There is a constant need to further improve the oil supply to the splined shaft.

[0005] The purpose of the invention is to demonstrate measures that enable improved oil supply to the splined connection.

[0006] The problem is solved by a shaft-hub connection with the features of claim 1. 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. 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 be a further development of the invention without the other feature.

[0007] One embodiment relates to a shaft-hub connection for a planetary gear unit, comprising a shaft, a hub element connected to the shaft via a splined connection about a main axis of rotation AR and surrounding the shaft circumferentially, wherein a housing element fixed with respect to the main axis of rotation is provided and an oil channel opening in the area of ​​the splined connection runs in the housing element and the hub element in order to supply lubricating oil to at least the splined connection via the oil channel, wherein the oil channel forms a lubrication gap between the housing element and the hub element for the transfer of lubricating oil and runs from radially inside to radially outside in the area of ​​the lubrication gap.

[0008] The main axis of rotation AR defines the axial direction, from which the respective radial directions result. Depending on the underlying configuration, the hub element can be designed as a hollow shaft. The splined connection, which positively engages the shaft and the hub element to transmit torque, can be described as a short spline. The spline can be helical. The hub element and the shaft can be supported by bearing arrangements, for example, relative to a gearbox housing structure that includes the housing element, with one of the bearings designed to absorb or support axial forces. The shaft can centrally accommodate a pitch tube through which electrical conductors are routed.

[0009] The housing element can be a cover of a gearbox housing. The cover can be attached to the gearbox housing and bolted in place. A main oil supply can be provided in the housing element, with the oil channel branching off from this supply. A seal is created between the stationary housing element and the rotating hub element via the lubrication gap. Oil transfer from a stationary component to a rotating component occurs via this lubrication gap. The lubrication gap therefore functions as an oil transfer point between a stationary and a rotating component. Preferably, a gearbox housing is provided in which the shaft-hub connection is accommodated, and the housing element is designed as an end-mounted housing cover of the gearbox housing. In particular, the arrangement can be such that the housing element is radially seated within the hub element.that the housing element is inserted radially inside the hub element.

[0010] It may be provided that a coating of a sliding material is applied to an inner circumferential surface of the housing element or an outer circumferential surface of the hub element. The sliding coating is primarily intended to protect against damage caused by tarnishing of the components.

[0011] In an alternative embodiment, a bushing can be arranged between the housing element and the hub element, and the lubrication gap can be formed between the bushing and the hub element. The bushing preferably consists of a copper-tin alloy.

[0012] In a preferred embodiment of the shaft-hub connection, at least one radial bore leads to at least one circumferential oil groove at the lubrication gap. Preferably, a plurality of radial bores are provided. These radial bores can be evenly distributed around the circumference. The bores can be circular or oval. The bores can also be slotted in the circumferential direction. For example, three or four slots can be provided around the circumference.

[0013] A preferred embodiment of the shaft-hub connection provides that, when the additional bushing is used, it is held rotationally fixed to the housing element. In particular, it is preferred that a defined radial distance exists or is set between the housing element or the optional bushing and the hub element, so that a lubrication gap is created between the housing element or the optional bushing and the rotating hub element.

[0014] In a particularly preferred embodiment, the bushing is provided with a circumferential oil groove on an inner circumferential surface and / or on an outer circumferential surface. In this case, it appears advantageous if the radial through-holes lie in an axial plane with the at least one oil groove. That is, the through-holes extend from the bottom of the oil groove. In the variant with the outer and inner circumferential oil grooves, these preferably lie in an axial plane of the bushing.

[0015] In an alternative embodiment of the shaft-hub connection, it can be provided that an inner circumferential surface of the hub element forms a circumferentially extending oil groove and that the oil groove lies in an axial plane with the radial through-bores of the bushing.

[0016] To regulate the amount of oil diverted from the main oil supply into the oil channel, the oil channel in the housing element can be guided through an orifice. Optionally, the orifice can also be located downstream of the lubrication gap in the oil channel within the hub section.

[0017] In one variant of the oil channel, it can be designed to open axially into the hub element in the area of ​​the splined connection. In a second variant of the oil channel, it can be designed to open radially into the hub element in the area of ​​the splined connection.

[0018] The shaft-hub connection is preferably designed such that the shaft and the hub element bear against each other via a pair of axial contact surfaces. Preferably, the oil channel opens in an axial area between the splined connection and the pair of axial contact surfaces. This advantageously allows both the splined connection and the pair of axial contact surfaces to be lubricated via the oil channel during operation, thereby reducing wear. Lubrication grooves can be incorporated into the two axial contact surfaces to improve lubrication of the contact surfaces of the two parts. Alternatively, or in combination, lubrication of the contact surfaces could also be achieved by means of a crown in one or both of the contact surfaces.

[0019] The problem is also solved by a gearbox for a wind turbine, consisting of at least one planetary stage and a hub element connected to the at least one planetary stage for drive, wherein at least one drive connection between several planetary stages and / or between the at least one planetary stage and the hub element is designed as a shaft-hub connection as described above. In particular, it can be provided that the subsequent planetary stage rotates faster than the preceding planetary stage.

[0020] The problem can also be solved by a drive train for a wind turbine, comprising a rotor shaft connected to a gearbox for torque transmission and a generator connected to the gearbox for torque transmission, the gearbox being designed as described above. Furthermore, the planetary gearbox and the generator can also be integrated into one another, i.e., designed as a generator gearbox.

[0021] Similarly, the underlying problem is solved by a wind turbine comprising a nacelle on which a multi-blade rotor is rotatably arranged and which is connected to a drive train in a torque-transmitting manner, the drive train being designed as described above.

[0022] The underlying problem is solved by data agglomeration using data packages either combined in a single file or distributed across multiple files. These packages represent the three-dimensional shape and / or the interactions of all components in a shaft-hub connection as described above. The data packages are designed to enable the additive manufacturing of the shaft-hub connection components, particularly through 3D printing using a 3D printer, and / or the simulation of the shaft-hub connection's functionality. This allows for the cost-effective production of prototypes and / or computer-based simulations to study the shaft-hub connection's functionality, identify problems in specific applications, and find improvements.

[0023] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination. The drawings show: Fig. 1 : a structural design of a shaft-hub connection; Fig. 2 to 4 : a first, second and third embodiment with a bushing located between the housing element and the hub element; Fig. 5 : another design without a bushing between the housing element and the hub element; Fig. 6a ), 6b): Views of the hub element and the shaft; Fig. 7 : a planetary gearbox in a drive train for a wind turbine and Fig. 8 : a perspective view of a wind turbine.

[0024] In the Figure 1A structural diagram of a possible configuration of a shaft-hub connection 10 is shown, the details of which are described in more detail below with reference to the following figures. The shaft-hub connection 10 is designed as a drive connection between a planetary gear stage 6 and a spur gear stage 8. Only a planet carrier PT and the meshing of the planet gears PR with a shaft 12 are shown for the planetary gear stage 6, where the shaft 12 is designed as a sun gear shaft. Only a hub element 14 and a gear ZR non-rotatably connected to it are shown for the spur gear stage 8. The hub element 14 is supported by a bearing arrangement L1 relative to a gearbox housing GG. Axial forces introduced into the outer hub element 14 can be supported by the bearing arrangement L1.The shaft 12 is supported in two ways: firstly, by a splined connection 16, through which the shaft 12 is drive-connected to the externally arranged hub element 14; and secondly, indirectly, by a bearing arrangement L2 of the planet carrier PT in the gearbox housing GG. The shaft 12 and the hub element 14 can rotate about a main axis of rotation AR. In an application where the shaft-hub connection 10 is used, for example, in a planetary gearbox for a wind turbine, a non-rotating pitch tube can run inside the shaft 12. The hub element 14 is also designed as a hollow shaft. The shaft 12 and the hub element 14 bear against each other via a pair of axial contact surfaces 20, 22. An axial force, which is introduced into the hub element 14 during operation, can be supported via the axial contact surfaces 20, 22.

[0025] The Figure 2Figure 1 shows a detailed view of the end section of the unit consisting of planetary gear 2 and spur gear stage 8. This is the section facing a generator unit, which is not shown. The gearbox housing 3 has a housing element here, designed as a housing cover 42. The housing cover 42 can, for example, be screwed to the rest of the gearbox housing 3. An oil distribution system 44 is provided in the structure of the housing cover 42, which is connected, for example, to an external oil pump that supplies pressurized lubricating oil.

[0026] An oil channel 24 is provided, extending from the oil distribution 44 and opening in the area of ​​the splined connection 16. The illustration shows that the oil channel 24 can open in an axial area between the splined connection 16 and the pairing of axial contact surfaces 20, 22. Lubricating oil can be supplied to the splined connection 16 via the oil channel 24. The oil channel 24 extends from the rotationally fixed housing cover 42 to the hub element 14, which rotates during operation. A non-contact bushing 26 is arranged between the housing cover 42 and the hub element 14 for the transfer of the lubricating oil. The bushing 26 has at least one radial through-bore 28. It can be seen that the bushing 26 forms several radial through-bores 28 around its circumference.The at least one through-hole 28 ensures that the lubricating oil can flow from the housing cover 42 into the hub element 14 via the bushing 26. The bushing 26 simultaneously serves as a seal between the housing cover 42 and the hub element 14, between which a relative rotation exists during operation. The bushing 26 is held rotationally fixed in the housing cover 42. A lubrication gap 54 is provided between the bushing 26 and the hub element 14. A baffle bore 40, which can also be described as a reduction in cross-section, is provided in the oil channel 24 of the housing cover 42 and allows the oil flow to be adjusted.

[0027] In the Figure 2An embodiment is shown in which the bushing 26 forms a circumferential oil groove 34 1 , 34 2 on both an inner circumferential surface 30 and an outer circumferential surface 32. The two oil grooves 34 1 , 34 2 are preferably located in an axial plane. Furthermore, it can be seen that the oil channel 24 opens into the hub element 14 via a radial path in the area of ​​the splined connection 16.

[0028] In the Figure 3 An embodiment is shown in which the oil channel 24 opens into the hub element 14 via an axial path in the area of ​​the splined connection 16. Otherwise, the embodiments correspond to the Figure 2 and 3 .

[0029] In the Figure 4An embodiment is shown in which the bushing 26 forms a circumferential oil groove 34 on an inner circumferential surface 30, and an inner circumferential surface 36 of the hub element 14 forms a circumferential oil groove 38. Furthermore, the oil groove 38 can also lie in an axial plane with at least one radial through-bore 28 of the bushing 26. Otherwise, the embodiments of the Figure 2 , 3 and 4 .

[0030] In the Figure 5 An embodiment without bushing 26 is shown. Instead, the lubrication gap 54 for the transfer of lubricating oil is formed directly between an inner circumferential surface 58 of the housing element 3 and an outer circumferential surface 36 of the hub element 14. A coating of a low-friction material can be provided, which is applied either to the inner circumferential surface 58 of the housing element 3 or to the outer circumferential surface 36 of the hub element 14.

[0031] The Figure 6 shows an axial view of shaft 12 - Fig. 6a ) - and a perspective sectional view of hub element 14 - Fig. 6b ). In the Figure 6a A contact shoulder 46 is visible, on which the axial contact surface 20 is arranged. A plurality of radially extending oil grooves 48 are arranged on the axial contact surface 20. The plurality of oil grooves 48 are evenly distributed around the circumference of the axial contact surface 20. In this case, eight oil grooves 48 are provided, although the number may vary. Figure 6b Figure 1 shows a contact shoulder 50 of the hub element 14, wherein the axial contact surface 22 is arranged laterally on the contact shoulder 50. A plurality of axially extending oil grooves 52 are arranged on a cylindrical surface 56 of the contact shoulder 50. The plurality of oil grooves 52 are arranged uniformly distributed over the circumference of the cylindrical surface 56.

[0032] The Figure 7Figure 2 shows, purely as an example, a planetary gear set 2, for instance, for a wind turbine. A first and second rotating planetary stages 4 and 6, and a spur gear stage 8 are arranged one after the other in a gear housing 3. A shaft-hub connection 10 is provided between the second planetary stage 6 and the spur gear stage 8 as a drive connection. It is possible that the second planetary stage 6 is designed to rotate at a higher speed than the first planetary stage 4.

[0033] In the Figure 8Figure 1 shows an embodiment of a wind turbine 70. The wind turbine 70 comprises a nacelle 71 to which a multi-blade rotor 72 is rotatably attached. The multi-blade rotor 72 is connected to a main shaft 74 for torque transmission, the main shaft 74 belonging to a drive train 76. The drive train 76 further comprises a planetary gear 2, which is connected to the main shaft 74 for torque transmission. The planetary gear 2 has at least one planetary stage 6 and one spur gear stage 8 and is coupled to a generator 80. In this embodiment, a shaft-hub connection 10 is provided between the planetary stage 6 and the spur gear stage 8 as a drive connection, the shaft-hub connection 10 being designed as described above. Reference symbol list

[0034] PR Planetary gear PT Planetary carrier L1, 2 Bearing arrangements ZR Gear GG Gearbox housing 2 Planetary gear 3 Gear element 4 Planetary stage 6 Planetary stage 8 Spur gear stage 10 Shaft-hub connection 12 Shaft 14 Hub element 16 Splined connection 18 End face 20 Axial contact surface 22 Axial contact surface 24 Oil channel 26 Bushing 28 Through hole 30 Inner circumferential surface 32 Outer circumferential surface 34 Oil groove 36 Inner circumferential surface 38 Oil groove 40 Blind hole 42 Housing cover 44 Oil distribution 46 Mounting shoulder 48 Oil groove 50 Mounting shoulder 52 Oil groove 54 Lubrication gap 56 Cylinder surface 58 Inner circumferential surface 70 Wind turbine 71 Nacelle 72 Multi-blade rotor 74 Main shaft 76 Drivetrain 80 Generator

Claims

1. Shaft-hub connection (10) for a planetary transmission (2), comprising a shaft (12), a hub element (14) drivingly connected to the shaft (12) about a main rotation axis (AR) via splines (16) and surrounding the outer circumference of the shaft (12), wherein a housing element (3) fixed with respect to the main rotation axis AR is provided, and an oil channel (24) extends in the housing element (3) and the hub element (14), the oil channel (24) opens out in the region of the splines (16), in order to supply at least the splines (16) with lubricating oil for oiling via the oil channel (24), characterized in that the oil channel between the housing element (3) and the hub element (14) forms a lubrication gap (54) for transferring lubricating oil and extends radially from the inside radially outwards in the region of the lubrication gap.

2. Shaft-hub connection (10) according to Claim 1, characterized in that a transmission housing (GG) is provided in which the shaft-hub connection (10) is received, and the housing element (3) is formed as an end-side housing cover (42) of the transmission housing (GG) .

3. Shaft-hub connection (10) according to Claim 1 or 2, characterized in that the housing element (3) sits radially inside the hub element (14).

4. Shaft-hub connection (10) according to any one of Claims 1 to 3, characterized in that a coating of sliding material is applied to an inner circumferential surface (58) of the housing element (3) or to an outer circumferential surface (36) of the hub element (14).

5. Shaft-hub connection (10) according to any one of Claims 1 to 4, characterized in that at least one bushing (26) is arranged between the housing element (3) and the hub element (14), and the lubrication gap (54) is formed between the bushing (26) and the hub element (14).

6. Shaft-hub connection (10) according to Claim 5, characterized in that the bushing (26) has at least one radial bore (28), preferably a plurality of bores (28) about the circumference.

7. Shaft-hub connection (10) according to Claim 5 or 6, characterized in that the bushing (26) is held for conjoint rotation on the housing element (3).

8. Shaft-hub connection (10) according to either of Claims 5 and 7, characterized in that the bushing (26), on an inner circumferential surface (30) and / or on an outer circumferential surface (32), forms a circumferentially extending oil groove (34), and the at least one radial bore (28) lies in an axial plane with the at least one oil groove (34).

9. Shaft-hub connection (10) according to Claim 8, characterized in that an inner circumferential surface (36) of the hub element (14) forms a circumferentially extending oil groove (38), and the oil groove (38) lies in an axial plane with the at least one radial bore (28) of the bushing (26).

10. Shaft-hub connection (10) according to any one of Claims 1 to 9, characterized in that, in the housing element (3) or in the hub element (14), the oil channel (24) is routed through an aperture bore (40), which is designated as a tapering of the cross section and by way of which the oil flow is adjusted.

11. Shaft-hub connection (10) according to any one of Claims 1 to 10, characterized in that the oil channel (24) opens out in the hub element (14) via an axial course in the region of the splines (16) or in the hub element (14) via a radial course in the region of the splines (16).

12. Shaft-hub connection (10) according to any one of Claims 1 to 11, characterized in that the shaft (12) and the hub element (14) bear against each other via a pair of axial contact surfaces (20, 22), and the oil channel (24) opens out in an axial region between the splines (16) and the pair of axial contact surfaces (20, 22).

13. Transmission (2), consisting of at least one planetary stage (4) and of a hub element (14) drivingly connected to the at least one planetary stage (4), wherein at least one drive connection between a plurality of planetary stages and / or between the at least one planetary stage (4) and the hub element (14) is designed as a shaft-hub connection (10) according to any one of Claims 1 to 12.

14. Drive train (76) comprising a shaft (74), which is torque-transmittingly connected to a transmission (2), and a machine (80), which is torque-transmittingly connected to the transmission (2), characterized in that the transmission (2) is designed according to Claim 13.

15. Wind turbine (70), comprising a nacelle (71) on which is rotatably arranged a multi-blade rotor (72) that is torque-transmittingly connected to a drive train (76), characterized in that the drive train (76) is designed according to Claim 14.