Lubrication of a spline at the output of a wind turbine gearbox
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- ZF FRIEDRICHSHAFEN AG
- Filing Date
- 2024-07-03
- Publication Date
- 2026-06-10
Smart Images
Figure EP2024068648_13022025_PF_FP_ABST
Abstract
Description
[0001] Lubrication of a spline at the output of a wind turbine gearbox
[0002] The invention relates to a wind turbine gear arrangement according to the preamble of claim 1.
[0003] EP 1 488 139 B1 discloses a lubricant transfer ring. This ring serves to connect a rotating planetary carrier to a stationary transmission housing in a lubricant-conducting manner.
[0004] The invention is based on the object of improving the lubricant supply to a spline that connects an intermediate shaft and an output shaft of a wind turbine gearbox in a rotationally fixed manner. This object is achieved by a wind turbine gearbox assembly according to claim 1. Preferred developments are contained in the subclaims and will become apparent from the following description.
[0005] A wind turbine gearbox assembly refers to an assembly designed to be used as a wind turbine gearbox or as part of a wind turbine gearbox. A wind turbine gearbox is a gearbox designed for use in the drivetrain of a wind turbine. As part of the drivetrain, the gearbox transmits the rotation of a wind-driven rotor to a generator.
[0006] The arrangement according to the invention comprises a housing, an output shaft, at least one intermediate shaft, at least one bearing arrangement and at least one transfer means for lubricant.
[0007] The output shaft is characterized by the fact that it is designed to transmit an output torque of the gearbox. The output shaft runs through the gearbox housing. This means that part of the output shaft is located inside the gearbox housing, while another part of the output shaft is arranged outside. The latter part is designed to be rotationally fixedly coupled to the rotor of a generator of the wind turbine. The intermediate shaft is located inside the gearbox housing and / or inside the output shaft. Like the output shaft, it has gearing. The gearing of the intermediate shaft and the output shaft mesh with each other to form a spline.
[0008] A spline generally refers to a multiple drive connection.
[0009] This is a rotationally fixed connection between two intermeshing gears that are coaxially aligned.
[0010] The housing has an extension. The term "extension" refers to a protrusion of the housing on the generator side. It is a housing part that extends toward a generator. The extension projects outwardly from the generator side. In particular, the extension can project outwardly from the rest of the housing, i.e., from the housing parts that are not part of the extension. The extension can form a separate housing part or be integrally connected to one or more parts of the rest of the housing.
[0011] The output shaft is rotatably mounted in the extension by means of the bearing assembly. This means that the output shaft is supported in the extension by means of the bearing assembly. The bearing raceways of the bearing assembly are each formed integrally by the output shaft, the extension, or a bearing ring that is joined to the output shaft or the extension.
[0012] According to the invention, the extension and the output shaft each have one or more lubricant lines. The lubricant lines of the extension and the output shaft are preferably integrated in one piece into the extension and the output shaft, respectively. This can be easily achieved by means of one or more bores that open into one another.
[0013] The transfer medium connects the lubricant lines of the extension and the lubricant line of the output shaft in a lubricant- and pressure-conducting manner. With a lubricant- and pressure-conducting connection between two lubricant lines, pressurized lubricant is transferred from one lubricant line to the other, at least partially, i.e., with possible leakage losses. The pressure is also transferred at least partially along with the lubricant.
[0014] In the present case, pressurized lubricant is thus at least partially conveyed by the transfer means from the lubricant line of the extension to the lubricant line of the output shaft, wherein the pressure is at least partially transferred from the lubricant line of the extension to the lubricant line of the output shaft.
[0015] Finally, the lubricant lines of the output shaft are connected to the spline for lubricant and pressure. According to the invention, pressurized lubricant flows from the lubricant lines of the extension via the transfer medium into the lubricant lines of the output shaft and from there into the spline.
[0016] The continuous pressure-conducting connection according to the invention overcomes centrifugal forces acting on the lubricant as a result of rotation of the intermediate shaft and the output shaft, which would otherwise force it away from the spline against the flow direction of the lubricant circuit. This ensures reliable lubrication of the spline under all operating conditions.
[0017] In a preferred embodiment, the transfer medium forms a cavity. The lubricant lines of the extension and the output shaft are connected to each other via the cavity for lubricant and pressure. Accordingly, a lubricant line of the output shaft and a lubricant line of the extension open into the cavity.
[0018] In a further preferred embodiment, the transfer means is formed by a ring and a groove. A ring generally refers to a rotationally symmetrical object with a central, continuous recess. In this case, the ring is rotationally symmetrical to a rotational axis of the output shaft and has at least two walls.
[0019] The groove is also rotationally symmetrical to the axis of rotation. This allows the ring to engage with its two walls in the groove in such a way that the ring and the groove form the aforementioned cavity. Either the extension has the ring and the output shaft has the groove, or the extension has the groove and the output shaft has the ring.
[0020] The ring can be designed as a separate piece and attached to a base body of the extension or output shaft. This allows the use of an elastomer ring. Such a ring is advantageous due to its elasticity, which allows contact between the ring walls and the groove. This reduces leakage losses occurring between the walls and the groove.
[0021] Alternatively, the ring can be made of a hard, inflexible material, such as metal. This requires a gap between the respective wall of the ring and the groove. While this results in leakage, such a ring is wear-free. In particular, it is possible to integrate the ring as a single piece into the extension or the output shaft.
[0022] In a preferred embodiment, the output shaft is mounted exclusively in the extension. This means that, apart from the aforementioned bearing arrangement, there are no additional bearings supporting the output shaft. According to the embodiment, the output shaft is supported exclusively by the bearing arrangement in the housing.
[0023] In a preferred embodiment, the intermediate shaft is at least partially supported by the spline in the output shaft. As a result, the output shaft absorbs at least part of the weight of the intermediate shaft. According to the embodiment, the output shaft and the intermediate shaft share the aforementioned bearing arrangement. Supporting the intermediate shaft in the output shaft is particularly advantageous for an intermediate shaft designed as a sun shaft of a planetary stage. In this case, the intermediate shaft is supported on one side by the spline in the output shaft and on the other side by a sun gear in the planetary gears of the planetary stage. Such a design compensates for tolerance-related bearing deviations within the planetary stage.
[0024] In a preferred embodiment, the intermediate shaft and the output shaft enclose a cavity. This cavity connects a lubricant line of the output shaft and the spline for lubricant and pressure transmission. The aforementioned lubricant line opens into the cavity. Furthermore, the cavity is directly adjacent to the spline. Apart from the outlet of the lubricant line of the output shaft, the cavity has no other openings.
[0025] This makes it lubricant and pressure conductive.
[0026] The output shaft is preferably designed as a hollow shaft, i.e., a shaft with an internal cavity that connects the end faces of the shaft to each other or opens into the end faces of the shaft. The spline is located within the hollow shaft, i.e., in the aforementioned cavity. Since one of the spline teeth is formed by the intermediate shaft, this implies that the intermediate shaft extends into the hollow shaft or cavity. Thus, according to the further development, a portion of the intermediate shaft is located in the intermediate shaft or cavity.
[0027] Preferably, the output shaft, which is designed as a hollow shaft, is further developed with a shoulder located inside the hollow shaft, i.e., in the cavity. The intermediate shaft rests against this shoulder with its generator-side end face. According to the development, the cavity enclosed by the intermediate shaft and the output shaft extends between the spline and the shoulder. It directly borders the spline and the shoulder.
[0028] An embodiment of the invention is shown in Fig. 1. In detail: Fig. 1 shows an output of a wind turbine gearbox.
[0029] Fig. 1 shows an output-side section of a transmission housing 101, in which an output shaft 103, designed as a hollow shaft, is mounted by means of a bearing arrangement 105. The bearing arrangement 105 consists of two tapered roller bearings arranged in an O-arrangement.
[0030] On the generator side, i.e., toward the right in Fig. 1, the output shaft 103 can be screwed to the rotor of a generator. The rotor has no bearings of its own and is completely supported by the output shaft 103.
[0031] The output shaft 103 is driven via an intermediate shaft 107. For this purpose, the output shaft 103 and the intermediate shaft 107 are coupled by means of a spline 109. The intermediate shaft 107 forms a corresponding external spline. An internal spline of the spline is located inside the output shaft 103. The external spline and the internal spline are aligned coaxially with each other and mesh with each other, creating a rotationally fixed connection between the output shaft 103 and the intermediate shaft 107.
[0032] The gear housing 101 forms an output-side or generator-side extension 111. This extension extends from a base body 113 of the gear housing 101 in the direction of the generator, i.e., to the right side in Fig. 1.
[0033] In the extension 101, next to the bearing assembly 105, there is a central section of the output shaft 103. Accordingly, the output shaft 103 is mounted in the extension 111 by means of the bearing assembly 105. The outer bearing rings of the bearing assembly 105 are joined to the extension 111, and the inner bearing rings are joined to the output shaft 103. A system of oil lines is provided for lubricating the spline 109. This includes a first oil line 115, which runs through a wall of the base body 113.
[0034] The first oil line 115 opens into a second oil line 117. The second oil line 117 consists of several interconnected holes formed in the extension 111. One of these holes branches off toward the bearing assembly 105 and opens into a cavity between the two bearings of the bearing assembly 105.
[0035] Another bore of the second oil line 117 opens into a third oil line 119. The third oil line 119 runs through a first intermediate ring 121. This is arranged inside the extension 111.
[0036] The first intermediate ring 121 has a U-shaped lubricant transfer ring 123. The third oil line 121 opens into this.
[0037] The lubricant transfer ring 123 engages a groove 124 extending in a second intermediate ring 125. The second intermediate ring 125 is fixed to the outer circumference of the output shaft 123.
[0038] A fourth oil line 127 opens into the groove. The fourth oil line 127 runs through the second intermediate ring 125. On the other side, it opens into a fifth oil line 129.
[0039] The fifth oil line 129 is formed by a bore in the output shaft 103. The bore extends radially through the output shaft 103 and opens into a sixth oil line 131.
[0040] The sixth oil line 131 runs through a third intermediate ring 133. This is located inside the hollow shaft 103. The sixth oil line 131 opens into a seventh oil line 135. The seventh oil line 135 is also formed by a bore in the output shaft 103. This bore runs in the axial direction and opens into a cavity 137.
[0041] The cavity 137 is formed by the output shaft 103 and the intermediate shaft 107. In the region of the cavity, the output shaft 103 has a shoulder 139. The intermediate shaft 107 rests against the shoulder 139 with its generator-side front end.
[0042] The spline 109 is located at a point in the cavity 137 axially opposite the shoulder 139. It directly borders the cavity 137. The spline 109 is therefore connected to the seventh oil line 135 via the cavity 137 in an oil-conducting manner.
[0043] Reference symbol
[0044] Gearbox housing Output shaft Bearing arrangement Intermediate shaft Spline Extension Base body First oil line Second oil line Third oil line First intermediate ring Lubricant transfer ring Groove Second intermediate ring Fourth oil line Fifth oil line Sixth oil line Intermediate ring Seventh oil line Cavity
[0045] Paragraph
Claims
Patent claims 1. A wind turbine gearbox assembly comprising a housing (101), an output shaft (103), a bearing assembly (105), an intermediate shaft (107), and a transfer means (123) for lubricant; wherein the output shaft (103) and the intermediate shaft (107) each have a toothing; wherein the toothings of the output shaft (103) and the intermediate shaft (107) form a spline (109); wherein the housing (101) has an extension (111) extending toward the generator side; and wherein the output shaft (103) is rotatably mounted in the extension (111) by means of the bearing assembly (105); characterized in that the output shaft (103) and the extension (111) each have one or more lubricant lines (117, 119, 127, 129, 131, 135); wherein the transfer means (123) connects the lubricant lines (117, 119) of the extension (111) and the lubricant lines (127, 129, 131, 135) of the output shaft (103) to one another in a lubricant- and pressure-conducting manner;and wherein the lubricant lines (127, 129, 131, 135) of the output shaft (103) are connected to the spline (109) in a lubricant and pressure-conducting manner; 2. Arrangement according to claim 1; characterized in that the transfer means (123, 124) forms a cavity; wherein a lubricant line (127, 129, 131, 135) of the output shaft (103) and a lubricant line (117, 119) of the extension (111) open into the cavity.
3. Arrangement according to the preceding claim; characterized in that the transfer means (123, 124) is formed by a ring (123) that is rotationally symmetrical to a rotational axis of the output shaft (103) and a groove (124) that is rotationally symmetrical to the rotational axis; wherein the ring (123) has two walls with which it engages in the groove (123) such that the ring (123) and the groove (124) form the cavity.
4. Arrangement according to one of the preceding claims; characterized in that the output shaft (103) is mounted exclusively in the extension (111).
5. Arrangement according to one of the preceding claims; characterized in that the intermediate shaft (107) is at least partially supported in the output shaft (103) via the spline (109).
6. Arrangement according to one of the preceding claims; characterized in that the output shaft (103) and the intermediate shaft (107) enclose a cavity (137) which connects a lubricant line (135) of the output shaft (103) and the spline (109) to one another in a lubricant- and pressure-conducting manner.
7. Arrangement according to one of the preceding claims; characterized in that the output shaft (103) is designed as a hollow shaft; wherein the spline (109) is located within the hollow shaft.
8. Arrangement according to claim 7 with reference to claim 6; characterized by a shoulder (139) in the interior of the output shaft (103); wherein the intermediate shaft (107) bears against the shoulder (139) with its generator-side end face; wherein the cavity (137) enclosed by the output shaft (103) and the intermediate shaft (107) extends between the spline (109) and the shoulder (139).