Lubrication device for a rolling bearing, method for lubricating a rolling bearing

Abstract

The invention relates to a lubricating device 100 for a rolling bearing 200 with a horizontally arranged shaft 300 mounted therein, and with an impeller 310 fixedly connected to the shaft 300 for generating a fluid flow F towards the rolling bearing 200, and furthermore with a container 400 open at both ends, the first open end 410 of which extends into the area of ​​an oil bath 500 of the rolling bearing 200, and the second open end 420 of which extends into the area of ​​the fluid flow F, so that depending on a rotational speed of the shaft 300 and the speed of the fluid flow F generated thereby, a portion of the oil from the oil bath 500 can be sucked into the container 400, wherein a level P of the oil in the oil bath 500 decreases and a level of the oil in the container 400 increases, and the oil, when the container is completely filled 400 can be released into the fluid stream F via the second open end 420.The invention further relates to a method for lubricating a rolling bearing and a preferred use of the lubricating device.

Description

The invention relates to the technical field of rotary bearings and more particularly to a lubricating device for a rolling bearing according to claim 1, a method for lubricating a rolling bearing according to claim 12 and a preferred use of the lubricating device according to the invention according to claim 14.Rolling bearings can be lubricated by various methods. Favourable solutions are available for low speeds. In general, the higher the rotational speed increases, the higher the technical outlay for lubricating the rolling bearings becomes.Thus, at low rotational speeds with n (rotational speed / minute) x dm (average diameter of the rolling bearing in mm)<=500,000 mm / min, oil bath lubrication is sufficient. At medium speeds, the use of splash lubrication is desirable. Finally, oil mist lubrication is recommended at very high rotational speeds with n.times.dm<=2,600,000 mm / min. Oil mist lubrication can only be achieved by supplying compressed air, which, however, is associated with high costs. In the structural design of the bearing, it must be determined which lubrication is used. The modification of the lubrication method is subsequently impossible or only possible with difficulty.Grease lubrication is generally preferred because of its simplicity, low costs and low maintenance expenditure. However, this lubrication is recommended only for speed characteristics n.times.dm<=500.000 mm / min.At high speeds, oil lubrication is usually used. Oil lubrication can again be divided into various types. Thus, oil bath lubrication or oil dew lubrication is suitable for rotational speed characteristics n.times.dm<=500,000 mm / min. The rolling elements thereby enter an oil bath and are lubricated in this way.The oil lubrication of the splash or centrifugal oil is particularly effective at n.times.dm>800,000 mm / min. Here, oil is sprayed or spun directly onto the rolling bodies. An oil build-up can, however, lead to foam formation, higher temperatures and friction. Therefore, oil drain holes must be provided. Finally, oil mist lubrication or oil-air lubrication is used for fast-running bearings with n x dm<=1,000,000 mm / min or n x dm<=2,600,000 mm / min. In this case, compressed air blows in the smallest amounts of oil into the rolling bearing. By avoiding splashing losses, such as in the case of spray or centrifugal oil lubrication, very high rotational speeds can be achieved at a comparatively low operating temperature. The oil lubricates the bearing and the air additionally cools.Solid lubrication is predominantly used for specific applications. In conventional bearing problems, grease or oil lubrication is the first choice.Oil mist lubrication is provided for very high speeds. For this purpose, a device must generate compressed air. Oil is mixed into the compressed air via a metering unit. The air cools the bearing and the oil lubricates the rolling elements. The costs and the construction outlay are very high in this solution. An oil-air lubrication system comprising a pump, a container, lines, a volumetric oil-air metering distributor, nozzles, a control system and a compressed air supply is required.The problem of lubrication of high speed bearings can be solved with oil mist lubrication, but with high cost for the additional plant parts compared to the other types of lubrication.SU 499 426 A1 discloses a lubricating device having a horizontally arranged shaft mounted therein and having an impeller which is fixedly connected to the shaft.DE 100 02 101 A1 relates to a device for supplying the bearings of a vertical shaft.DE 20 2014 007 850 U1 discloses a vacuum pump having at least one rotor element arranged in a pump chamber and a rotor shaft.DE 10 2005 029 638 A1 relates to a device for filling the oil compensation container of a transmission.FR 3 086 012 A1 shows a vacuum pump.DE 35 40 842 A1 relates to a lubricant centrifugal disk for lubricants for a side chamber, partially filled with oil, of a rotary piston vacuum pump.It is therefore an object of the present invention to provide a simple, cost-effective and reliable method for lubricating a rolling bearing at both low, medium and high speeds.This object is achieved by a lubricating device for a rolling bearing according to claim 1, having a horizontally arranged shaft mounted therein, and having an impeller which is fixedly connected to the shaft for generating a fluid flow toward the rolling bearing, and furthermore having a container which is open at both ends and the first open end of which extends into the region of an oil bath of the rolling bearing, and the second open end of which extends into the region of the fluid flow, with the result that, depending on a rotational speed of the shaft and the speed of the fluid flow generated therewith, a proportion of the oil can be sucked from the oil bath into the container, wherein a level of the oil in the oil bath decreases and a level of the oil in the container increases, and the oil can be discharged into the fluid flow via the second open end when the container is completely filled.An essential point of the invention is to make it possible, depending on the speed of the shaft, to use either oil bath lubrication or oil mist lubrication. No external actuator is required for the adjustment of the lubrication method. In addition, no compressed air supply is necessary. At low speeds, oil bath lubrication is used. At high speeds, the system changes over to oil mist lubrication without an external signal or actuator.Advantageous further developments of the lubricating device according to the invention are specified in the dependent claims.It is provided here that the impeller and / or the container is dimensioned and designed such that the rolling bearing runs in an oil-circulated lubricated oil in the oil bath in a transition speed range of the shaft and at the same time oil-circulated lubricated in an oil mist, preferably in a transition speed range of approximately 9,500 to 10,500 revolutions / minute. In the transition speed range, both types of lubrication are thus simultaneously active, while in the speed ranges separated by this transition range, below and above this, the respectively ideal type of lubrication is active. In this case, in comparison with the environment, a static negative pressure prevails in the fluid stream, by means of which the amount of oil sucked into the container is exactly as much as the level of the oil bath must decrease in order to no longer let the rolling bearing run in the oil bath itself, but in an oil mist. In addition, the volume of the oil bath can of course also be adjusted in order to adjust the turnover range. The lubricating device according to the invention can thus be adjusted in multiple ways to provide ideal lubrication of a rolling bearing, in particular also to other ideal turning-over regions of the lubrication depending on the bearing.In a second preferred embodiment of the lubricating device according to the invention, it is provided that the impeller is arranged before and / or behind the rolling bearing, as viewed in the axial direction of the shaft, and is in particular designed as an impeller through which flow takes place radially, axially or semi-axially. It is only decisive here whether the generated fluid flow is guided past in the region of the second open end of the container, so that a reduced pressure in comparison with the environment arises at this point. The roller bearing lubrication according to the invention can thus be designed for a wide variety of structural conditions of a roller bearing and its housing.In a further preferred embodiment of the lubricating device according to the invention, it is provided that a fixed guide wheel is provided for orienting the fluid flow onto the rolling bearing in order to achieve as efficient a lubrication as possible. At the same time, the selection of the impeller can be made more flexible with regard to possibly given design restrictions.Preferably, it is provided that a combination of impeller and guide wheel is dimensioned and designed such that the fluid flow is diverted when it hits the rolling bearing and does not pass through the rolling bearing. In the case of a corresponding diversion of the fluid flow through this combination of the rotor and the stator, entrained oil droplets are thrown out of the fluid flow and in the direction of the rolling bearing on account of their inertia, which enables its more targeted (injection) lubrication.In a further preferred embodiment of the lubricating device according to the invention, it is provided that the second open end of the container is formed in the shape of a nozzle in order to enable a finer distribution of the oil injected into the fluid stream.In a further preferred embodiment of the 5 lubricating device according to the invention, it is provided that the first open end of the container has a filter in order not to suck in any impurities potentially located in the oil bath and thus to clog the second open end of the container, in particular a nozzle located there.In a further preferred embodiment of the lubricating device according to the invention, it is provided that the second open end of the container lies within a guide channel of the fluid flow towards the impeller. The suction effect of the fluid stream can thus be significantly increased by reduced pressure generated in the guide channel and this can also be directed in a targeted manner toward the rolling bearing, which increases the efficiency of the lubrication.It is particularly preferred in this case if the guide channel is designed as a chamber with a throttle opening for the fluid flow, as a result of which a suction effect corresponding to a particularly low static pressure force can be generated on the second open end of the container.Furthermore, it is preferred if the guide channel has a shielding against the blowing out of oil provided in the region of the oil bath in order to minimize oil losses in the fluid stream.In a further preferred embodiment of the lubricating device according to the invention, it is finally provided that the rolling bearing is surrounded by a housing on the intake side of the fluid stream and / or on the side opposite this intake side, and compensation openings for oil and fluid are provided between the intake side and the opposite side. This allows in particular a formation of negative pressure on the intake side of the fluid stream and / or also a formation of positive pressure on the opposite side to be assisted in order to increase lubrication of the rolling bearing. The return flow of the fluid and the oil via the compensation openings follows a pressure difference between both sides, whereby even at very high rotational speeds sufficient fluid and oil is always available for lubricating the rolling bearing on the intake side.The above object is also achieved by a method for lubricating a rolling bearing, in which a fluid stream is generated depending on the rotational speed of a shaft mounted horizontally in the rolling bearing and of an impeller rotating in a movement-coupled manner with the shaft, which fluid stream is directed at the rolling bearing, and which draws oil from an oil bath into a container as the rotational speed of the shaft increases, whereby a level of the oil bath decreases, and which discharges oil from this container into the fluid stream as the rotational speed of the shaft increases further, whereby an oil mist stream is generated.An essential point of the method according to the invention is that a defined transition region can be defined for respectively ideal lubrication of the rolling bearing as a function of a rotational speed of the shaft, and oil mist lubrication can be carried out without external compressed air. This method is preferably to be operated with a lubricating device according to the invention, the structure and mode of operation of which is simple and efficient. In principle, the use of the lubricating device according to the invention for shafts of all types is conceivable. However, this should preferably be used for lubricating the bearing of electric motor shafts, in particular rapidly rotating electric motor shafts.Further advantages, goals and properties of the present invention will be explained with reference to the following description of the attached figures. Like components may have like reference numerals in the various embodiments. In the figures, the following are shown: FIG. 1 is a sectional side view of a rolling bearing with a first embodiment of the lubricating device according to the invention in oil circulation lubrication; FIG. 2 shows a sectional side view of a rolling bearing with a first embodiment of the lubricating device according to the invention in oil passage lubrication; FIG. 3 is a sectional side view of a rolling bearing with a second embodiment of the lubricating device according to the invention in oil circulation lubrication; FIG. 4 is a sectional side view of a rolling bearing with a third embodiment of the lubricating device according to the invention in oil circulation lubrication; FIG. 5a is a sectional side view of a combination of the rotor and guide wheel according to the invention of a third embodiment of the lubricating device according to the invention in oil passage lubrication, and FIG. 5 bshows a sectional side view of a combination according to the invention of rotor and stator of a fourth embodiment of the lubricating device according to the invention in oil passage lubrication.FIG. 1 shows a sectional side view of a rolling bearing 200 with a first embodiment of the lubricating device 100 according to the invention in oil circulation lubrication. A shaft 300 is rotatably mounted in a rolling bearing 200. Arranged on the left adjoining the rolling bearing 200 is an impeller 310 which is fixedly connected to the shaft 300 and interacts with a stationary stator 210. On the left next to the combination of the rotor and stator 310, 210, a container 400 is attached, the first open end 410 of which reaches into the region of an oil bath 500, and the second open end 420 of which reaches into the region of the fluid flow F which is generated by the rotor and stator 310, 210 towards the rolling bearing 200. The fluid flow F is guided in a guide channel 600 to the combination of the rotor and guide wheel 310, 210 in order to assist the formation of a reduced pressure and to supply the fluid flow F to the rolling bearing 200 in a targeted manner. The rolling bearing 200 itself is accommodated in a housing 700 into which the shaft 300 extends. The rolling bearing 200 here parts the housing in two halves which communicate via passage openings 710 for the fluid and 720 for the oil.The combination of the rotor and guide wheel 310, 210 conveys a fluid, such as air, and generates a negative pressure. At low speed, impeller 310 mounted on shaft 300 produces only low vacuum. The rolling bodies are lubricated exclusively by oil bath lubrication. As the speed increases, a cavity of the container 400 becomes filled with oil more and more because of the negative pressure. Thus, a level P of the oil in the oil bath 500 continuously decreases and the rolling elements are no longer lubricated via the oil bath 500, but via an oil mist lubrication shown in FIG. 2. There will be a transition range of speeds at which both lubricating modes are active simultaneously. At high speeds, oil is discharged through the second opening 420 of the reservoir 400. Depending on the viscosity and surface tension, the oil breaks down into more or less large droplets. The impeller 310 draws in these droplets and sprays them. These reduced oil droplets are transported to the rolling elements via the guide wheel 310. There, the oil lubricates the rolling bearing 200. The air either flows through the rolling bearing 200 or is previously diverted. The oil mist lubrication in this invention is accomplished without external compressed air.FIG. 2 shows a sectional side view of a rolling bearing 200 with 5 of a first embodiment of the lubricating device 100 according to the invention in oil passage lubrication. In this case, a rotational speed of the shaft 300 has been reached at which the container 400 is soaked with oil and the oil is discharged into the fluid stream F via the second opening 420 of the container 400. In this state, the level P of the oil bath 500 has dropped below a rolling element height due to the extraction of oil into the container 400, so that the rolling elements only still rotate in the oil mist. As a result of the guide channel 600 and its lower shield facing the oil bath, there is no oil losses into the oil bath, but rather a targeted and loss-free supply of the fluid stream F to the rolling bearing 200. In the left-hand housing half, a reduced pressure is generated by the rotor and guide wheel 310, 210, which vacuum draws in the fluid and oil guided over the rolling bearing again through the passage openings 720 and 710, respectively.FIG. 3 shows a sectional side view of a rolling bearing 200 with a second embodiment of the lubricating device 100' according to the invention in oil circulation lubrication. In contrast to the embodiment of FIG. 2, a guide channel 600' with a throttle opening 610 is provided for the fluid flow F, which ensures an increase in the negative pressure in the guide channel 600'. In addition, a second open end 420' of the container 400 is designed in the form of a nozzle, so that finer atomization of the oil into the fluid stream F is possible. Other openings for the oil are also possible. A vacuum prevails in the guide channel 600', which can suck in oil from any desired point. The nozzle 420', or orifice 610, and oil inlet need not be at a same position. This makes a more flexible design possible in particular, so that, for example, an oil inlet can be positioned directly in front of the impeller inlet.FIG. 4 shows a sectional side view of a combination according to the invention of the rotor and guide wheel 310, 210 of a third embodiment of the lubricating device 100" according to the invention in oil passage lubrication. In contrast to the embodiments of FIGS. 1 to 3, the rotor wheel and guide wheel 310, 210 is provided here on the right side of the rolling bearing 200. The guide wheel 210 is held in a holder 620, similar to the guide channel 600, behind the impeller 310 in the flow direction of the fluid flow F. The impeller 310 is mounted on the shaft 300 at a distance from the rolling bearing 200, so that friction losses are not directly transmitted to the rolling bearing 200, but are blown into the space of the housing 700.FIG. 5a shows a sectional side view of a combination according to the invention of the rotor and guide wheel 310', 210' of a third embodiment of the lubricating device 100''' according to the invention in oil passage lubrication. In this embodiment, impeller 310' accelerates an aerosol of air and oil. The air is deflected at the rolling bearing, wherein the oil is pressed against the rolling bodies due to its inertia. The fluid flow F runs from the impeller 310' via the rolling bearing 200 to the guide wheel 210', wherein a part of a guide channel 600" formed there follows substantially the contour of the impeller and guide wheel 310, 210'. The air then drains outwardly and is retarded in the stator 210', thereby increasing the static pressure. The advantage here is that the air does not flow through the rolling bearing 200 and thus lower pressure losses are produced.FIG. 5 bshows a sectional side view of a combination according to the invention of the rotor and guide wheel 310, 210 of a fourth embodiment of the lubricating device 100""according to the invention in oil passage lubrication. Here too, the impeller 310 accelerates an aerosol of air and oil, which is deflected in a combined guide wheel 210'' / guide channel 600''' in the direction of the rolling bearing 200, as a result of which the static pressure increases. Behind the combined guide wheel 210'' / guide channel 600''', the fluid stream F is then guided away to the outside. Due to the deflection, oil with a higher density than air is pressed against the rolling bodies. Here too, there is the advantage that the air does not flow through the rolling bearing 200 and lower pressure losses are thereby produced.List of reference characters100 .. 100""' Lubricator 200 Rolling bearing 210, 210' Stator 300 Shaft 310, 310' Impeller 400 Container 410 First opening of container 420, 420' Second opening of container 500 Oil bath 600... 600"' Guide channel 610 Throttle opening 620 Holder 700 Housing 710 Passage opening for oil 720 Passage opening for fluid F Fluid flow P Oil level

Claims

Lubricating device (100... 100''') for a rolling bearing (200) having a horizontally arranged shaft (300) mounted therein, and having an impeller (310, 310') which is fixedly connected to the shaft (300) for generating a fluid flow (F) toward the rolling bearing (200), and furthermore having a container (400) which is open at both ends and the first open end (410) of which extends into the region of an oil bath (500) of the rolling bearing (200), and the second open end (420) of which extends into the region of the fluid flow (F), such that, depending on a rotational speed of the shaft (300) and the speed of the fluid flow (F) generated therewith, a proportion of the oil can be sucked from the oil bath (500) into the container (400), wherein a level (P) of the oil in the oil bath (500) decreases and a level of the oil in the container (400) increases, and the oil can be discharged into the fluid stream (F) via the second open end (420) when the container (400) is fully filled, wherein the impeller (310, 310') and / or the container (400) is dimensioned and configured such that the rolling bearing (200) runs in an oil mist in an oil-rotated manner in a transition rotational speed range of the shaft (300) and at the same time in an oil mist in an oil-rotated manner in an oil-rotated manner, preferably in a transition rotational speed range of approximately 10,000 revolutions / minute.Lubricating device (100... 100''') according to claim 1, characterised in that the impeller (310, 310') is arranged before and / or behind the rolling bearing (200), as viewed in the axial direction of the shaft (300), and is in particular designed as an impeller (310, 310') through which flow takes place radially, axially or semi-axially.Lubricating device (100... 100"") according to one of the preceding claims, characterized in that a fixed guide wheel (210, 210') is provided for orienting the fluid flow (F) onto the rolling bearing (200).Lubricating device (100... 100"") according to claim 3, characterized in that a combination of impeller (310, 310') and guide wheel (210, 210') is dimensioned and configured such that the fluid flow (F) is diverted such that it does not pass through the rolling bearing (200) when it impinges on the rolling bearing (200).Lubricating device (100... 100"') according to one of the preceding claims, characterized in that the second open end (420) of the container (400) is of nozzle-shaped design.Lubricating device (100... 100"') according to any one of the preceding claims, characterized in that the first open end (410) of the container (400) comprises a filter.Lubricating device (100... 100"") according to any of the preceding claims, characterized in that the second open end (420) of the container (400) is inside a guiding channel (600... 600''') of the fluid stream (F) towards the impeller (310, 310').Lubricating device (100... 100"") according to claim 7, characterized in that the guide channel (600... 600"') is designed as a chamber with a throttle opening (610) for the fluid flow (F).Lubricating device (100... 100"") according to claim 7 or 8, characterized in that the guide channel (600... 600"') has a shielding provided in the region of the oil bath (500) against the blowing out of oil.Lubricating device (100... 100"") according to one of the preceding claims, characterized in that the rolling bearing (200) is surrounded by a housing (700) on the intake side of the fluid stream (F) and / or on the side opposite this intake side, and compensation openings for oil (710) and fluid (720) are provided between the intake side and the opposite side.Method for lubricating a rolling bearing (200), in which a fluid stream (F) is generated depending on the rotational speed of a shaft (300) mounted horizontally in the rolling bearing (200) and of an impeller (310, 310') rotating in a movement-coupled manner with the shaft (300), said fluid stream being directed at the rolling bearing (200), and which draws oil from an oil bath (500) into a container (400) as the rotational speed of the shaft (300) increases, as a result of which a level of the oil bath (500) falls, and which discharges oil from said container (400) into the fluid stream (F) as the rotational speed of the shaft (300) increases further, as a result of which an oil mist stream is generated.Method according to claim 11, comprising a lubricating device (100... 100"") according to any one of claims 1 to 10.Use of a Lubricating Device (100... 100"') according to one of claims 1 to 10 for lubricating the bearing of electric motor shafts, in particular rapidly rotating electric motor shafts.

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