Gear arrangement with a lubricating oil hollow shaft

Abstract

Gear arrangement with a hollow shaft (4) rotatably mounted in a gear housing (1), through which lubricating oil (3) contaminated with dirt particles is passed, which exits the end face of the hollow shaft (4) to enter an oil sump (2) formed on the bottom of the gear housing (1), characterized in that a hollow cylindrical or annular disc-shaped centrifugal disc (11) projecting axially and radially from the end face of the hollow shaft (4) is arranged to direct the lubricating oil (3) exiting the hollow shaft (4) towards the oil sump (2).

Description

[0001] The invention relates to a gearbox arrangement with a hollow shaft rotatably mounted in a gearbox housing, through which lubricating oil contaminated with dirt particles is passed, exiting the end face of the hollow shaft to enter an oil sump formed at the bottom of the gearbox housing. The invention further relates to a wind turbine comprising such a gearbox arrangement.

[0002] The application area of ​​the invention extends primarily to gearboxes for vehicles and industrial plants, especially wind turbines. Here, a gearbox, which usually has several planetary gear sets and / or spur gear stages, is used to translate a slow rotor movement into a high speed for driving an electric generator to produce electricity.

[0003] The gearboxes of the type of gearbox of interest here are oil-lubricated and have an oil sump located at the bottom of the gearbox housing, which serves to store the lubricating oil. From the oil sump, the lubricating oil is cleaned by a filter assembly and directed to the bearings and gear teeth of the gearbox that require lubrication. Various oil channels and bores are integrated within the gearbox to create a lubricating oil circuit, allowing the lubricating oil to return to the oil sump.

[0004] Within a gearbox's internal oil circuit, it is essential to ensure that used lubricating oil – i.e., oil contaminated with dirt particles – does not enter the area of ​​the rolling bearings during its return to the oil sump, as the dirt particles contained in the used lubricating oil would cause increased wear of the rolling bearings. Lubricating fluids are used for this purpose within a circulating lubrication system.

[0005] German patent DE 1 830 664 U discloses a geared motor whose gearbox incorporates circulating lubrication using special lubricating agents to ensure lubricant circulation in every position of the gearbox. An impeller, eccentrically mounted at the end of a shaft, projects into a reservoir filled with lubricating oil and is connected via a channel running parallel to the shaft. This channel connects to an internal gearbox space containing a centrifugal disc rotating on a second shaft. This arrangement circulates the lubricating oil and returns it to the reservoir under the required pressure, thus ensuring continuous and adequate lubrication of the gears.The lubricating oil accumulating on the centrifugal disc is scraped off by a stationary nose, dammed up and forced into an oil channel, from where the lubricating oil then flows back into the reservoir under the influence of gravity.

[0006] DE 12 739 14 A discloses a lubrication device for a gear with a horizontal axis of rotation and with two annular chambers for the lubricant. One chamber, located on one side of the gear disc, collects the lubricant in the lower region when the gear is stationary. The lubricant is then distributed by centrifugal force, which occurs when the gear rotates, through connecting channels into the second chamber, located on the other side of the gear disc and acting as a distribution chamber. This second chamber is connected to the gaps in the gear teeth via further connecting channels.

[0007] According to DE 43 29 398 A1, a rolling bearing should achieve good protection against penetrating foreign bodies and good lubrication supply by having side discs that lie tightly against an inner ring and form a labyrinth gap towards an outer ring, wherein the side discs are made of porous or perforated material.

[0008] From DE 90 02 218 U1, a gear bearing designed as a rolling bearing is known, in which the lubricating oil entering the bearing from the outside is cleaned by a filter element. This filter element consists of a support disc and one or more filter elements connected to it, and is arranged directly in front of the rolling element raceway and attached to the stationary bearing ring. A centrifugal disc is connected to the rotating bearing ring. This disc is arranged on the side of the support disc facing away from the rolling elements, and its outer edge is positioned in the area of ​​the filter elements, causing the lubricating oil to be flung off towards the filter elements.

[0009] US patent 5 242 033 A discloses a cooling system for a high-speed transmission with multiple channels extending through the transmission and a hydraulic slip ring that directs coolant to the channels and extracts it after it has passed through the channels.

[0010] In contrast, in the gearbox arrangement of interest here, at least one hollow shaft is integrated into the oil circuit, at the end of which the lubricating oil exits.

[0011] The object of the present invention is to further improve a generic gear arrangement in such a way that the lubricating oil exiting at the end of the hollow shaft is directed to the oil circuit.

[0012] The problem is solved starting from a transmission arrangement according to the preamble of claim 1 in conjunction with its characterizing features. The following dependent claims describe advantageous embodiments of the invention.

[0013] The invention includes the technical teaching that a hollow cylindrical or circular disc-shaped centrifugal disc, projecting axially and radially from the end face of the hollow shaft, is arranged as an oil guide in order to direct the lubricating oil exiting the hollow shaft directly towards the oil sump.

[0014] The advantage of the arrangement according to the invention lies particularly in the fact that the lubricating oil diverted via the centrifugal disc cannot run along the outer circumference of the hollow shaft, but is instead specifically diverted away from it when the hollow shaft is in rotational motion. Thus, the lubricating oil can be kept away from a functional component located adjacent to the shaft end – in particular a rolling bearing. This prevents dirt particles contained in the lubricating oil from penetrating into the area of ​​the rolling bearing and causing wear.

[0015] According to a preferred embodiment of the invention, the hollow shaft is rotatably mounted in the gearbox housing in the area of ​​the centrifugal disc via at least one rolling bearing, with the lubricating oil being directed past the rolling bearing via the centrifugal disc to the oil sump in order to protect the rolling bearing from the dirt particles contained in the lubricating oil.

[0016] Preferably, the centrifugal disc has an outer diameter that is larger than the inner diameter of the rolling bearing. This geometric relationship ensures that the lubricating oil passing through the centrifugal disc is directed away from the rolling bearing. Furthermore, for this purpose, the centrifugal disc can be provided with a molded-on flange at the outer edge where the lubricating oil separates from the disc. Depending on its angle, the flange can widen the point where the lubricating oil separates from the centrifugal disc in the axial and / or radial direction, thus allowing the geometric dimensions of the centrifugal disc's base body to be kept small.

[0017] To ensure an unimpeded flow of lubricating oil at the transition point between the hollow shaft and the centrifugal disc, it is proposed that the inner diameter of the hollow shaft correspond to the inner diameter of the hollow cylindrical or annular centrifugal disc. It is also possible for the inner diameter of the centrifugal disc to be larger than the inner diameter of the hollow shaft to ensure an unimpeded flow of lubricating oil.

[0018] The lubricating oil discharged from the outer edge of the centrifugal disc can be directed directly towards the oil sump or via additional oil guides, preferably located in the gearbox housing. For this purpose, at least one oil return bore in the gearbox housing is suitable, which collects the lubricating oil discharged from the centrifugal disc and directs it towards the oil sump.

[0019] According to a preferred embodiment of the invention, the centrifugal disc interacts on approximately the same plane with an annular, oil baffle disc that is stationary in the gearbox housing and bears against the end face of the outer ring of the rolling bearing, in order to more reliably prevent the ingress of the lubricating oil discharged by the centrifugal disc into the area of ​​the rolling bearing. In this case, the centrifugal disc should project axially beyond the oil baffle disc. In its radial extent, the oil baffle disc should cover the end face of the rolling bearing at least up to the level of the center of the rolling elements.

[0020] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures. The figures show: Fig. 1: a partial section through a gear assembly with a special lubricant guide, and Fig. 2: a detailed partial section through a centrifugal disc of the gear arrangement according to Fig. 1.

[0021] The gearbox arrangement according to Fig. 1 comprises a gearbox housing 1 – only partially shown here – in which an oil sump 2 is arranged at the bottom. The oil sump 2 serves to store lubricating oil 3, which is circulated through the gearbox elements of the gearbox assembly as part of a circulating lubrication system.

[0022] In the gearbox housing 1, a hollow shaft 4 is rotatably mounted via rolling bearings 5 ​​to 7 arranged at each shaft end. While rolling bearings 5 ​​and 6 are designed as tapered roller bearings, rolling bearing 7 is a cylindrical roller bearing.

[0023] A toothed ring 8 of a gear (not shown) is integrally formed on the outer circumference of the hollow shaft 4. This ring meshes with other gears of the transmission assembly and is also immersed in the oil sump 2 for lubrication. In the area of ​​the rolling bearing 7, the hollow shaft 4 forms a splined connection 10 with the external splines of a connecting shaft 9 via internal splines to transmit the torque flow within the transmission. The lubricating oil 3 flows through the splined connection 10 to lubricate and flush it. The lubricating oil 3, subsequently contaminated with dirt particles, exits the hollow shaft 4 at its end face in the area of ​​the rolling bearings 5 ​​and 6 and passes through a substantially hollow cylindrical centrifugal disc 11, which projects axially and radially from the shaft.This allows the lubricating oil 3 to flow past the rolling bearing 5 via the centrifugal disc 11 to the oil sump 2, protecting the outer rolling bearing 5 and the adjacent rolling bearing 6 from dirt particles contained in the lubricating oil 3. The hollow cylindrical centrifugal disc 11 has an outer diameter larger than the inner diameter of the rolling bearing 5 to ensure targeted lubricating oil flow. Furthermore, the centrifugal disc 11 interacts in approximately the same plane with an annular, oil baffle disc 12, which is stationary in the gearbox housing 1 and rests against the end face of the outer ring of the rolling bearing 5. The oil baffle disc 12 prevents the lubricating oil diverted by the centrifugal disc 11 from entering the area of ​​the rolling bearings 5 ​​and 6. For this purpose, the centrifugal disc 11 projects axially beyond the oil baffle disc 12.

[0024] The lubricating oil 3 discharged by the centrifugal disc 11 enters the oil sump 2 via an oil return bore 13 provided in the gearbox housing 1. Between the oil return bore 13 and the centrifugal disc 11, the lubricating oil also passes through the area of ​​a gearbox cover 14, which together with the gearbox housing 1 forms a channel for the passage of the lubricating oil 3.

[0025] According to Fig. 2 The centrifugal disc 11 is provided at the outer radial separation point of the lubricating oil 3 with a flanged section 15 that projects beyond it in both the axial and radial directions. The flanged section 15 of the centrifugal disc 11 conveys the lubricating oil departing from the centrifugal disc 11 further outwards, without the need to dimension the basic dimensions of the essentially hollow cylindrical centrifugal disc 11 to a correspondingly large extent.

[0026] The invention is not limited to the preferred embodiment described above. Rather, variations thereof are also conceivable, which are also covered by the scope of protection of the following claims. For example, it is also possible to design the hollow shaft 4 without gears. In addition, the centrifugal disc 11 arranged on the end face of the hollow shaft can protect a functional component other than a rolling bearing from a backflow of lubricating oil 3 contaminated with dirt particles. Reference sign 1 Gearbox housing 2 Oil sump 3 Lubricating oil 4 hollow shaft 5 rolling bearings 6 rolling bearings 7 rolling bearings 8-tooth sprocket 9 Connecting shaft 10 Plug-in spline 11 Slingshot disc 12 Oil pressure sensor plate 13 Oil return bore 14 Gearbox cover 15 Federal Section

Claims

[1] Gear arrangement with a hollow shaft (4) rotatably mounted in a gear housing (1), through which lubricating oil (3) contaminated with dirt particles is passed, exiting the end face of the hollow shaft (4) to enter an oil sump (2) formed on the bottom side of the gear housing (1), characterized by , that a hollow cylindrical or annular disc-shaped centrifugal disc (11) is arranged axially and radially projecting from the end face of the hollow shaft (4) in order to direct the lubricating oil (3) exiting the hollow shaft (4) towards the oil sump (2). [2] Gear arrangement according to claim 1, characterized by , that the hollow shaft (4) is rotatably mounted in the gearbox housing (1) in the area of ​​the centrifugal disc (11) via at least one rolling bearing (5 to 7), wherein the lubricating oil (3) is directed via the centrifugal disc (11) past the rolling bearing (5) to the oil sump (2) in order to protect the rolling bearing (5) from the dirt particles contained in the lubricating oil (3). [3] Gear arrangement according to claim 2, characterized by , that the hollow cylindrical centrifugal disc (11) has an outer diameter that is larger than the inner diameter of the rolling bearing (5; 6). [4] Gear arrangement according to claim 1, characterized by , that the inner diameter of the hollow shaft (4) is greater than or equal to the inner diameter of the hollow cylindrical or annular disc-shaped centrifugal disc (11). [5] Gear arrangement according to claim 1, characterized by , that the lubricating oil (3) discharged by the centrifugal disc (11) flows back into the oil sump (2) via at least one oil return bore (13) provided in the gearbox housing (1). [6] Gear arrangement according to claim 2, characterized by, that the centrifugal disc (11) interacts in a plane with a circular annular disc-shaped oil baffle disc (12) which is fixed in the gearbox housing (1) and comes into contact with the outer ring of the rolling bearing (5) in order to prevent the ingress of the lubricating oil derived from the centrifugal disc (11) into the area of ​​the rolling bearing (5). [7] Gear arrangement according to claim 6, characterized by , that the centrifugal disc (11) extends beyond the oil baffle disc (12) in the axial direction. [8] Gear arrangement according to one of the preceding claims, characterized by , that the centrifugal disc (11) is provided at the outer edge separation point of the lubricating oil (3) with a flanged section (15) molded protruding from it. [9] Gear arrangement according to one of the preceding claims, characterized by, that the hollow shaft (4) at the end opposite the rolling bearing (5) forms a splined connection (10) with the external splined connection of a connecting shaft (9) via an internal spline, through which the lubricating oil (3) flows. [10] Gearbox of a wind turbine comprising a gearbox arrangement according to any of the preceding claims.

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