Grease retention and oil measurement device for a roller bearing unit

Abstract

[Grease retention and oil measurement device for a roller bearing unit] Grease retention (42) and oil measurement (42') device (70) for a bearing unit (10) having a radially external ring (20) having a central circular groove (22) formed on an internal surface (23) thereof; the grease retention (42) and oil measurement (42') device (70) having a radially external rim (74) arranged in the groove (22); an annular wall (72) engaged in the radially external rim (74); a radially internal cylindrical rim (71) arranged opposite the radially external rim (74) and engaged in the annular wall (72); a plurality of partitions (75) attached to both the annular wall (72) and the two rims (71)(74) and defining, between themselves and with the annular wall (72) and the two rims (71)(74), a plurality of retention cells (80) for the lubricating grease (42);in which the radially external rim (74) has an axial width (L1) having dimensions less than the dimensions of an axial width (L2) of the radially internal rim (71) and of an axial width (L3) of the assembly formed by two axially aligned partitions (75) and by the annular wall (72) so as to place each cell directly in communication with the radially external ring (20).

Description

Title of the invention: Grease retaining and oil measuring device for a roller bearing unit Technical field of the invention

[0001] The present invention relates to a grease retaining and oil measuring device for a roller bearing.

[0002] The present invention also relates to a roller bearing unit provided with a grease retaining and oil measuring device, in particular, a roller bearing unit suitable for applications in the railway sector, to which the description below will refer without losing its general character. State of the prior art

[0003] As is known, any type of roller bearing unit requires proper lubrication during its operation and typically, for this purpose, mineral or synthetic oil based lubricating greases are used, such greases mainly comprising:

[0004] - a base oil providing the necessary lubrication to minimize the friction in the bearing unit;

[0005] - a thickener, also called "soap" or "thickening agent", to give from the consistency of lubricating grease and to properly retain and release the base oil;

[0006] - certain additives to enhance and improve certain application characteristics of said lubricating grease.

[0007] In lubricating greases of the type described above, for the purpose of proper lubrication, it is necessary that the base oil be released from said thickener, and this release occurs both due to mechanical stresses and due to thermal stresses acting on the lubricating greases which are inserted inside the roller bearing units, substantially in a central area thereof, but which in operation can migrate to the various components of said roller bearing units, which also occurs entirely randomly, due to various factors, most of which are entirely uncontrollable.The result of this uncontrollable migration of lubricating grease is that often some areas of the roller bearing units that require greater lubrication receive instead small amounts of lubricating oil and grease and tend to wear more quickly, while on the other hand some other areas of the roller bearing unit that require less . lubrication systems receive huge amounts of lubricating grease, creating unwanted leaks and build-ups due to friction.

[0008] Grease retaining and oil measuring devices of the known type are mounted in the inner central area of ​​roller bearing units precisely in order to promote correct distribution of the lubricating grease and correct measurement of the base oil and, in roller bearing units used in applications in the railway sector, where there are usually two rows of rolling bodies interposed between a rotating radially inner ring and a fixed radially outer ring, these grease retaining and oil measuring devices are mounted precisely between two rows of rolling bodies and are integral with the rotating radially inner ring.

[0009] Grease retaining and oil measuring devices of the type described above comprise:

[0010] - a radially internal cylindrical rim;

[0011] - an annular wall engaged in the radially internal cylindrical rim and defining a barrier to the lubricating grease, but provided with a plurality of through openings to allow oil to pass between the two rows of rolling bodies;

[0012] - a radially external cylindrical rim, coaxial with the cylindrical rim radially internal and connected to it by means of the annular wall; and

[0013] - a plurality of radial partitions, which are integral with both the annular wall and the two cylindrical rims, extend axially on opposite sides of the annular wall and connect the two cylindrical rims together, creating, on both sides of the annular wall, a plurality of retention cells for the lubricating grease, these cells being connected to each other by means of through openings, being axially open towards the two rows of rolling bodies and being radially delimited by the two cylindrical rims so that the lubricating grease contained therein cannot come into direct contact with the inner and outer rings of the rolling unit.

[0014] In retaining and measuring devices of the type described above, while on the one hand the formation of the retaining cells has greatly improved the distribution of lubricating grease within the associated roller bearing units and the axial openings have contributed to improving the measurement of the released base oil, a number of disadvantages have, however, been encountered, these being due primarily to the fact that the release of the base oil occurs primarily due to the mechanical stresses induced by the operation of the roller bearing unit rather than for other reasons, with the result that the release is limited and therefore there is also a reduced lubricating capacity. Summary of the invention

[0015] The object of the present invention is to provide a grease retaining and oil measuring device for a roller bearing unit, which device is capable of overcoming the disadvantages of the known devices described above, allowing both the distribution of the lubricating grease inside the roller bearing unit, i.e. hindering the free flow of the grease, and at the same time allowing the release of the base oil therefrom in a controlled manner, even in the absence of mechanical stresses.

[0016] This and other objects and advantages, which will be understood more clearly below, are achieved with the present invention which provides a grease retaining and oil measuring device for roller bearings having the features recited in the appended claims. Brief description of the figures

[0017] The invention will now be described with reference to the attached drawings which illustrate a non-limiting example of an embodiment thereof, in which:

[0018] [Fig-1] is a schematic axial sectional view of a retaining device grease and oil meter for roller bearing units according to the present invention;

[0019] [Fig.2] is an enlarged view of the grease retaining and oil measuring device for roller bearing units shown in [Fig.l];

[0020] [Fig.3] is a side elevational view of the grease retaining and oil metering device for roller bearing units shown in [Fig.l];

[0021] [Fig.4] is a perspective side view of the grease retaining and oil measuring device for roller bearing units shown in [Fig.l]. Detailed Description of the Invention

[0022] With reference to [Fig.l], 10 generally denotes a roller bearing unit which is suitable in particular for applications in the railway sector, but which can also be used in other technical sectors, such as the automotive or renewable energy sectors.

[0023] Purely by way of example, the invention described here will now refer to a roller bearing unit which is particularly suitable for applications in the railway sector, where the dimensions of said roller bearing unit are relatively large with an internal diameter of between 90 and 185 mm and where, consequently, the management of the lubrication thereof, both in operation and also during transport and handling, poses major problems which, if not addressed appropriately, can negatively affect the correct operation thereof.

[0024] The rolling unit 10 has a central axis of rotation X and comprises an outer ring 20, which is stationary and has two radially inner raceways 21, two rotatable inner rings 30, which are coaxial with the outer ring 20 and the axis X and which have respective radially outer raceways 31 facing radially with the raceways 21, and a spacer 40 interposed axially between the two inner rings 30. The rolling unit 10 also comprises, for each inner ring 30, a row 50 of rolling bodies 51, in this example tapered bearings, which is arranged in the raceways 21 and 31 so as to allow rotation of the inner ring 30 relative to the outer ring 20, and a retaining cage 60 for keeping the rolling bodies 51 angularly equidistant from each other about the axis X.

[0025] As also shown more clearly in [Fig. 2], the outer ring 20 is provided, in an axially intermediate position between the two raceways 21 and in a position facing radially the central spacer 40, with a central and circular groove 22 which is formed through a cylindrical surface 23 and which is arranged in a radially internal position with respect to the outer ring 20 and in an axially intermediate position between the two raceways 21 and defines, together with the spacer 40, an annular compartment 4L. The annular compartment 41 is arranged axially between the rolling bodies 51 and the associated cages 60 and, for the purpose of lubrication and reducing friction between the rolling bodies 51, the raceways 21 and 31 and the cages 60, is substantially filled with lubricating grease, shown schematically in dotted lines and indicated by 42 on the [Fig.2].This lubricating grease 42 is a lubricating grease of known type and will not be described here in detail, but, for the purpose of understanding the text, it is only emphasized that this lubricating grease 42 comprises a base oil which, for simpler illustration, will generally be indicated by 42' and which provides the necessary lubrication to minimize friction, and a thickener - which, again for simpler illustration, will generally be indicated by 42” and which is also referred to as “soap” or “thickening agent” - which gives the lubricating grease 42 consistency and also retains and / or releases the base oil 42' depending on the operating conditions of the bearing unit 10. .

[0026] As already mentioned, the roller bearing unit 10 according to the present invention has relatively large dimensions and, therefore, for the purpose of optimal distribution of both the lubricating grease 42 and the oil 42', it comprises a device 70 for retaining the lubricating grease 42 and measuring the oil 42' which is housed in the compartment 41 in an intermediate position and arranged between the two rows 50 of rolling bodies 51 and prevents the migration of the lubricating grease 42 from one row 50 of rolling bodies 51 to another and also provides additional support for said lubricating grease 42 both in the case where the rolling unit 10 is transported with its X axis in the vertical position and under normal operating conditions of the rolling unit 10 itself.

[0027] In particular, the lubricating grease 42 retaining and oil 42' measuring device 70 according to the present invention optimally performs its functions both during transport of the rolling unit 10, acting as an impermeable barrier for the lubricating grease 42 and actually preventing any migration of the lubricating grease 42 between the two rows 50 of rolling bodies 51 in particular when the rolling unit 10 is transported with its X axis in the vertical position, and during operation of the rolling unit 10, retaining the lubricating grease 42 inside the compartment 41, i.e. preventing uncontrolled dispersion of the lubricating grease 42 inside the rolling unit 10, thereby improving the wear and reliability of said rolling unit 10.Furthermore, as will be explained more clearly below, the lubricating grease 42 retaining and oil 42' metering device 70 also provides for better metered feeding and separation of the base oil 42' from the thickener 42” not only as a result of mechanical stresses due to the operation of the bearing unit 10, but also as a result of thermal stresses due to the heating of said bearing unit 10 during the operation thereof.

[0028] In accordance with what is also shown in Figures 3 and 4, the device 70 for retaining lubricating grease 42 and measuring oil 42' comprises:

[0029] - a radially internal cylindrical rim 71 arranged opposite the spacer 40;

[0030] - an annular wall 72 engaged in the radially internal cylindrical rim 71 and defining a barrier with respect to the lubricating grease 42, but provided with a plurality of through openings 73 to allow the base oil 42' to pass between the two rows 50 of rolling bodies 51;

[0031] - a radially external cylindrical rim 74, coaxial with the cylindrical rim radially internal 71 and connected to it by means of the annular wall 72; and

[0032] - a plurality of radial blades or partitions 75 which are integral with both the annular wall 72 and the two cylindrical rims 71 and 74, extend axially on opposite sides of the annular wall 72 and connect the two cylindrical rims 71 and 74 together, creating on the two axial sides of the annular wall 72 a plurality of cells 80 for containing the lubricating grease 42.

[0033] The radial vanes or partitions 75 further increase the number of lubricating grease retaining surfaces 42, preventing their dispersion inside the unit of bearing 10. The through openings 73 are uniformly distributed around the X axis according to two concentric circumferences of different diameters from each other and, although they connect the areas of the two rows of rolling bodies 51 together, they do not affect the necessary capacity of the annular wall 22 to stop the migration of the lubricating grease 42, further promoting the characteristics of the device 70 for retaining the lubricating grease 42 and measuring the oil 42' during its two functions: retaining the lubricating grease 42 in the areas where it is required to remain and measuring the supply of base oil 42' of said lubricating grease 42.

[0034] Furthermore, due to the increase in the retaining surfaces due to the presence of the partitions or vanes 75, the lubricating grease 42 is stored more efficiently inside the lubricating grease 42 retaining and oil measuring device 70 42', being divided into small quantities inside the cells 80, thus avoiding the formation of a single shapeless mass which is particularly subject to the movements and vibrations of the bearing unit 10: these small quantities are not affected by the force of gravity. At the same time, in addition, each cell 80 allows the base oil 42' of the lubricating grease 42 to be uniformly distributed inside the rolling unit 10, which improves the performance and wear resistance thereof, and to migrate from one row 50 of rolling bodies 51 to another via the openings 73, with which the annular wall 72 is provided.Again due to the presence of the openings 73, the base oil 42' can migrate from one row 50 of rolling bodies 51 to another, promoting lubrication of the bearing unit.

[0035] As already mentioned above, the radially outer rim 74 of the lubricating grease 42 retaining and oil measuring device 70 42' is arranged inside the groove 22 or, more precisely, is snap-fitted inside said groove 22 and, according to the present invention, is made with a diameter ¢1 having dimensions larger than the dimensions of an outer diameter ¢2 of the groove 22. In reality, the radially outer rim 74 is flexible and can be substantially compressed so as to be inserted inside the groove 22 and allowed to expand so as to snap-fit ​​inside said groove 22.The elasticity of the material from which the radially outer rim 74 - and preferably, but not necessarily, the entirety of the lubricating grease 42 retaining and oil metering device 70 42' - is made will cause the radially outer rim 74 to expand against the groove 22 of the outer ring 20, providing, in use, radial pressure on an end wall 24 of said groove 22.

[0036] As shown more clearly in the detail of [Fig. 3], for the purpose of further facilitating the snap-fit ​​engagement of the lubricating grease retaining device 70 42 and oil metering device 42' within the groove 22, the lubricating grease retaining and oil measuring device 42' has a structural discontinuity, namely an incision 90, which is formed in both the radially outer rim 74 and the radially inner rim 71 as well as in the annular wall 72, and, by interrupting the structural continuity thereof, provides the lubricating grease retaining and oil measuring device 42' with a greater deformation capacity when it is to be inserted inside said groove 22.

[0037] The radially external rim 74 has an axial width L1 of dimensions smaller than the dimensions of an axial width L2 of the groove 22 and the dimensions of an axial width L3 of the assembly formed by two partitions or blades 75 with the annular wall 72. This difference in width is such that each cell 80 has a respective radial window 81 directly facing the surface 23 of the external ring 20, allowing the lubricating grease 42 contained inside it to come into contact with said external ring 20. Each radial window 81 rests on a respective cylindrical arc and is delimited, axially towards the annular wall 72, by an edge 811 defined by the radially external rim 72, while it is delimited laterally by two edges 812 parallel to the axis X and defined by the partitions or blades 75. Of course, each window 81 is open axially outward as is the associated cell 80.

[0038] Despite the presence of the windows 81, the cells 80 do not in any way lose their function of dividing the lubricating grease 42 from the compartment 41 into small quantities within it, but additionally acquire the function of promoting the heating of the lubricating grease 42 contained within it, thus ensuring better separation of the base oil 42', i.e. more efficient use of all the characteristics of the lubricating grease 42. In reality, the windows 81 allow the lubricating grease 42 contained inside the associated cells 80 to come into direct contact with the surface 23 of the outer ring 20, allowing optimal heating of the lubricating grease 42 and thus helping the separation of the base oil 42' and therefore - thanks also to the configuration of the device 70 for retaining lubricating grease 42 and measuring oil 42' - the measurement of said base oil 42'.The base oil 42', being separated in larger quantities due to the direct contact between the lubricating grease 42 and the outer ring 20, not only is better distributed within the compartment 41, but, from there, is distributed from the lubricating grease 42 retaining and oil metering device 70 42' to the rolling bodies 51, the raceways 31 and the cages 60, allowing an even better reduction of the rolling friction between these components.

[0039] By defining the difference between the dimensions of the width L1 and the width L2 relative to the two dimensions of the bearing unit 10 and also the characteristics of the lubricating grease 42, it is possible, without increasing production costs, to provide a wide range of lubricating grease 42 retaining and oil 42' measuring devices 70, suitable for many applications not only in the railway sector, but also in the automotive or renewable energy sectors.

[0040] With the above-described use of the lubricating grease 42 retaining and oil measuring device 70, it is possible to introduce a larger quantity of lubricating grease 42 into the central compartment 41 of the bearing unit 10 since the lubricating grease 42 retaining and oil measuring device 70 'ensures greater retaining capacity and stability of the lubricating grease 42 in terms of loads, vibrations and heat during the lifetime of the bearing unit 10, limiting the migration of the lubricating grease 42 in the case where the bearing unit 10 is transported with its X axis vertical;furthermore, the base oil 42' of the lubricating grease 42 in the lubricating grease 42 retaining and oil measuring device 70 42' will be released inside the bearing unit 10 not only in a more controlled manner, but also in larger quantities for the same quantity of lubricating grease 42, which allows effective lubrication for a longer period of time and consequently with longer intervals between scheduled maintenance operations of the bearing unit 10. ;

[0041] The invention has been designed to be applied to rolling units 10 having rolling bodies 51 in the form of tapered rollers, in particular rolling units 10 having two rows 50 of rolling bodies 51 in the form of tapered rollers, where the device 70 for retaining lubricating grease 42 and measuring oil 42' can be mounted centrally between the two rows 50 of rolling bodies 51. Such applications include both the case where the inner ring of the rolling ring can rotate while the outer ring of the rolling unit is fixed and the opposite case, thus ensuring, in both cases, the static state of the device 70 for retaining lubricating grease 42 and measuring oil 42'. The device 70 for retaining lubricating grease 42 and measuring oil 42' can in any case also be applied in a lateral position relative to the rows of rolling bodies and on other types of roller bearings.Furthermore, although the lubricating grease 42 and oil measuring 42' device 70 has been shown in combination with a tapered roller bearing unit 10, the same device, according to the present invention, can also be used with other different types of bearing units.

[0042] More generally, it is understood that the invention is not limited to the embodiments described and illustrated here, which must be considered as examples. of the bearing unit and the lubricating grease retaining and oil measuring device; those skilled in the art may make various modifications to the functions and configuration of the elements described in the exemplary embodiment, without departing from the scope of the invention as defined in the appended claims and their equivalents.

Claims

Claims

1. A grease (42) retaining and oil (42') measuring device (70) for a bearing unit (10) comprising: - a radially outer ring (20) which has a central circular groove (22) formed on an inner surface (23) of said radially outer ring (20); - two radially inner rings (30); and - two rows of rolling elements (51) interposed between the radially outer ring (20) and the two radially inner rings (30); the grease (42) retaining and oil (42') measuring device (70) comprising: - a radially outer rim (74) arranged in the groove (22); - an annular wall (72) engaged in the radially outer rim (74) and defining an axial barrier with respect to the lubricating grease (42); - a radially internal cylindrical rim (71) arranged opposite the radially external rim (74) and in turn engaged in the annular wall (72);- a plurality of partitions (75) integral with both the annular wall (72) and the two rims (71)(74) and defining between them and with the annular wall (72) and the two rims (71)(74) a plurality of retention cells (80) for the lubricating grease (42); the device (70) for retaining grease (42) and measuring oil (42') being characterized in that the radially external rim (74) has an axial width (L1) of dimensions smaller than the dimensions of an axial width (L2) of the radially internal rim (71), as well as an axial width (L3) of the assembly formed by two partitions (75) aligned axially and by the annular wall (72) to place each cell (80) directly in contact with the radially external ring (20).;

2. A grease retaining and oil measuring device according to claim 1, characterized in that each cell (80) is provided with a respective radial window (81) directly facing a surface internal (23) of the radially external ring (20) so as to allow the lubricating grease (42) contained therein to come into contact with said radially external ring (20).

3. Grease retaining and oil measuring device according to claim 2, characterized in that each radial window (81) rests on a respective cylindrical arc and is delimited by a respective edge (811) defined by the radially external rim (74) and is delimited laterally by two edges (812) parallel to the axis (X) and defined by the partitions (75).

4. A grease retaining and oil measuring device according to claim 3, characterized in that each window (81) is axially open outwards as is the associated cell (80).

5. A grease retaining and oil measuring device according to claim 3, characterized in that the annular wall (72) has a plurality of through openings (72) of dimensions defined according to the characteristics of the lubricating grease (42) and the base oil (42').

6. Roller bearing unit (10) comprising: - a radially outer ring (20) which has a central circular groove (22) formed on an inner surface (23) of said radially outer ring (20); - two radially inner rings (30); and - two rows of rolling elements (51) interposed between the radially outer ring (20) and the two radially inner rings (30); and - a grease (42) retaining and oil (42') measuring device (70) according to any one of the preceding claims.

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