EP-4737720-A1 - LUBRICATION UNIT AND LUBRICATION SYSTEM

EP4737720A1EP 4737720 A1EP4737720 A1EP 4737720A1EP-4737720-A1

Abstract

Inventors

HOVE, THOMAS

Assignees

Danhydra A/S

Dates

Publication Date: 20260506
Application Date: 20251022

Claims (14)

Lubrication unit (1) for a bearing (2) comprising - a container (6) comprising a reservoir for lubricant and comprising an inlet (12) and an outlet (12) for lubricant, - a hose or tube or pipe (13) configured to fluidly connect the lubrication unit (1) to the bearing (2), characterized in that the lubrication unit (1) comprises a distribution chamber (14) which distribution chamber (14) comprises an inlet (11) for lubricant from an external source, an outlet (12) for lubricant to the container (6), an inlet (12) for lubricant from the container (6), and an outlet (10) for lubricant to the bearing (2).
A lubrication unit (1) according to claim 1, wherein the lubrication unit (1) is secured to a surface of the bearing (2) during operation.
A lubrication unit (1) according to any previous claim, wherein the lubrication unit (1) is fluidly connected to the bearing by a rigid connection.
A lubrication unit (1) according to claim 2, wherein an end of the pipe (13) configured to be fixed to the bearing (2) comprises an outer thread adapted to fit a corresponding inner thread of an opening (9) in a bearing (2).
A lubrication unit (1) according to any previous claim, wherein the distance between the container (6) of the lubrication unit (1) and surface of the bearing (2) to which it is mounted is less than 1 m, or less than 0,5 m, or less than 0,4 m or less than 0,2 m.
A lubrication unit (1) according to any previous claim, wherein the lubrication unit (1) comprises controlling means (8, 17) controlling the amount of lubricant supplied to the bearing (2).
A lubrication unit (1) according to claim 6, wherein the controlling means comprises a pump (8) and a valve (16).
A lubrication unit (1) according to claim 7, wherein opening and closing of the valve (16) is controlled by air supplied via an air supply line (15).
A lubrication system comprising a lubrication unit (1) according to any of the claims 1-8, which lubrication system further comprises a bearing (2).
A lubrication system according to claim 9, wherein the system comprises at least two lubrication units (1), or at least three lubrication units (1), or at least four lubrication units (1), or at least five lubrication units (1), or at least six lubrication units (1).
A lubrication system according to claim 9 or 10, wherein the bearing (2) is a roller bearing, a ball bearing, a slider bearing or the like.
A lubrication system according to any of the claims 9-11, wherein the bearing (2) is a large bearing having an inner diameter of at least 1 m, or of at least 2 m, and/or of maximum 10 m.
A lubrication system according to any of the claims 9-12, wherein the bearing is applied as a pitch bearing in a wind turbine.
A lubrication system according to any of the claims 9-13, wherein each opening (9) in the bearing (2) comprises fastening means adapted to fix a pipe (13) of the lubrication unit (1) to the bearing (2).

Description

The present invention relates to a lubrication unit for a large bearing. Such large bearings may be used in wind turbines, and normally each bearing may be equipped with two, three, four or more lubrication units. In particular, the present invention relates to a decentralized lubrication unit for a large bearing. Background of the invention Normally, large wind turbines have rotor blades that can be pitched about their longitudinal axes, and the circular root end of a rotor blade terminates at a pitch bearing. A pitch system actuates one or more drive motors in response to a command from the wind turbine controller to pitch the rotor blade by a determined angular amount, and a reliable lubrication of the pitch bearing is very important. Damage to a pitch bearing can result in wind turbine downtime resulting in a lower annual energy production. The reliability of the pitch bearings is particularly relevant in the case of an offshore wind turbine because service routines are expensive and hazardous. A rotor blade of a large wind turbine can have a length in the region of 90 m, a mass in the region of 50000 kg and a root end diameter in the order of 5 m. The pitch bearing of such a large rotor blade may be realised as a roller bearing, a ball bearing, a slider bearing, etc. The stationary part and the rotating part of the bearing are always separated by a film of oil or grease. Since lubricant deteriorates over time, a pitch bearing is generally equipped with a lubricant system which is able to replenish the lubricant as required. Various lubrication systems are available, and most systems include a grease reservoir and one or more feeder lines to grease inlets of the bearing. Controlled quantities of grease are fed at intervals into the bearing. In a single-line lubrication system, a pump station delivers lubricant through a single supply line to a lubricant metering device serving a single lubrication point. A pitch bearing of a large rotor blade can have several such lubrication points. In a progressive lubrication system, lubricant is continually transported to various lubrication points as long as the lubricant pump is running. When the pump is halted, the pistons of a metering device will also stop, and will "hold" their positions. When the pump starts supplying lubricant again, the metering device pistons resume from those positions. Also, grease deteriorates over time, and the used grease must be removed and collected in a controlled manner and replaced by new grease. Normally, grease is fed to the large bearing of a wind turbine by a centralized lubrication system. According to a centralized lubrication system grease is provided from one, two or three grease reservoirs and pumped into one or more bearings. Due to the relatively long tubes guiding grease from the centralized reservoir(s), the grease has to be pumped by a relatively high pressure. CN 22168424 U published 10 September 2024 shows a lubrication unit for a printing press bearing which lubrication unit is attached directly to the bearing. The lubrication device is provided with automatic oil level detection and comprises an oil storage tank, a bearing body arranged below the oil storage tank, wherein the oil storage tank is fixedly mounted on the bearing body through a plurality of support rods. A display (10) is fixedly mounted on top of the oil storage tank, an oil filling hole (4) and an oil outlet groove (5) are respectively provided at the top and at the right side of the bearing body, a connecting box (6) is fixedly connected to the oil outlet groove (5), a detection box is fixedly mounted on the connecting box. A liquid level sensor (15) being electrically connected to the display is arranged inside the detection box. The oil adding mechanism includes a pressure plate (901), a threaded rod (902) and a smooth rod (903), the pressure plate is slidably arranged inside the oil storage tank, a threaded rod is rotatably installed and a smooth rod is fixedly installed on the left and right sides of the oil storage tank respectively, the thread of the threaded rod passes through the pressure plate, and the smooth rod movably passes through the pressure plate. The pressure plate can move up and down on the inner side of the oil storage tank during the rotation of the threaded rod. When moving downward, it pushes the lubricating oil deposited on the lower side and supplies lubricating oil into the bearing body through the oil filling pipe and the oil filling hole. When moving upward, the internal space is vacated to facilitate the addition and storage of new lubricating oil through the refuelling groove (23) at the top of the oil storage tank. This system is difficult to control especially when delivering batchwise doses to a bearing. Hence, an improved lubrication system where the grease need not be pumped by a high pressure would be advantageous, and in particular a system comprising highly reliable lubrication units comprising automatic sup