Grease dispensing device for rolling bearings

Abstract

The rolling bearing unit (10) is provided with a radial outer ring (11), two radial inner rings (12, 13), two rows of rolling elements (16) and a grease distribution device (30). The radial outer ring has an assembly groove (18). The two rows of rolling elements are located between the radial outer ring and the radial inner ring and define a first internal grease storage section (25) between them. The groove is located at the middle position in the axial direction relative to the two radial inner rings. The grease distribution device is housed inside the groove of the radial outer ring and is provided with: a second grease storage section (31) formed inside the radial outer ring and communicating with the first grease storage section via the groove; and a permeable retaining wall (32) housed inside the groove to retain grease inside the second storage section (31) and allow grease to flow toward the first storage section during operation of the bearing unit, thereby distributing grease in a controllable manner.

Description

Technical Field

[0001] This invention relates to a grease dispensing device for rolling bearings. More specifically, the device is adapted to retain grease and then distribute it during the working cycle of the bearing.

[0002] This invention is particularly applicable to the railway sector, where the rolling bearings used have large dimensions, with an inner bore measured between 90 mm and 160 mm. However, the invention is applicable to all technical fields, and other non-limiting examples of application include the motor vehicle sector and the renewable energy sector. The invention is designed for bearings with rollers, particularly bearings with two rows of rollers, and the device can be mounted at the center between the two rows of rollers and used as a grease dispensing device. These applications include two cases: where the inner ring of the bearing rotates while the outer ring is fixed; and where the inner ring of the bearing is fixed while the outer ring rotates. In either case, the dispensing device can be used in a lateral position relative to the rows of rolling elements and can be used for other types of rolling bearings. Background Technology

[0003] As is known, any type of rolling bearing requires proper lubrication during its life cycle (operational state). Typically, the type of grease used is a lithium soap-thickened mineral oil, which has good thermal stability, oxidation resistance, mechanical strength, and excellent water and rust protection properties.

[0004] For example, in the case of a bearing with two rows of rolling elements, grease is typically inserted into the central region between the two rows. During bearing operation, due to many factors (most of which are uncontrollable), the grease migrates between the various parts of the bearing in a completely random manner. As a result, some areas that typically require more lubrication receive less grease and tend to wear faster, while on the other hand, grease accumulates in areas that require less lubrication, leading to undesirable leaks due to friction.

[0005] Grease dispensing devices or lubricating cartridges are known, their purpose being to retain grease, create a barrier against its free flow, and distribute grease in a sufficiently controlled manner during bearing operation. For example, US 5803616 describes a grease dispensing device mounted on the outer ring of a bearing, between two rows of tapered rollers, and having a central annular reservoir defined axially by a honeycomb structure. This central annular reservoir effectively retains grease and allows for its dispensing, but it must withstand centrifugal forces and occupies a considerable amount of axial space between the two rows of tapered rollers, thus greatly limiting its application. Summary of the Invention

[0006] The purpose of this invention is to provide a grease dispensing device that overcomes the shortcomings of known devices.

[0007] According to the present invention, a rolling bearing comprising a grease dispensing device having the features described in the appended claims is provided. Attached Figure Description

[0008] The invention will now be described with reference to the accompanying drawings, which illustrate non-limiting examples of embodiments of the invention, in which:

[0009] Figure 1 This is an axial cross-sectional view of a bearing having two rows of rollers, which is provided with a preferred embodiment of the grease distribution device according to the invention;

[0010] Figure 2 yes Figure 1 A magnified view of the details taken axially; and

[0011] Figure 3 and Figure 4 Shown at a large scale Figure 2 Two close-ups of the details. Detailed Implementation

[0012] Reference Figure 1 10 represents the bearing unit as a whole, which has a rotation axis X and includes:

[0013] The outer ring 11 is stationary;

[0014] A pair of rotating inner rings 12 and 13 are strung together axially along axis X and arranged radially inside outer ring 11;

[0015] Two rows (or double rows) of rolling elements 16, in this example tapered rollers, are positioned between the outer ring 11 and the inner rings 12 and 13; and

[0016] The retainer 15 for each row of tapered rollers 16 is used to hold the tapered rollers 16 in their seats and to keep the tapered rollers 16 angularly equidistant from each other.

[0017] Each cage 15 includes:

[0018] The cavity 21 for each tapered roller 16 is used to accommodate the corresponding tapered roller 16;

[0019] A separation crosspiece 22 parallel to axis X is provided for each cavity 21, and the separation crosspiece 22 is disposed between each cavity 21 and the adjacent cavity 21; and

[0020] The two side edges 23 and 24 are transverse to the axis X and are integral with the associated cross member 22 and the cross member 22 of the adjacent cavity 21. The edge 23 of the two side edges 23 and 24 is axially disposed inside the edge 24 of the associated cage 15 and axially faces the edge 23 of the cage 15 of another row of tapered rollers 16 to define an annular reservoir 25, which is adequately filled with lubricant (usually a grease of mineral oil thickened with lithium soap) to ensure adequate lubrication during the operation of the bearing unit 10.

[0021] The bearing unit 10 also includes a spacer 17, which is axially positioned between the inner rings 12 and 13. The outer ring 11 in this invention is designed to remain stationary while the inner rings 12 and 13 rotate. The bearing unit 10 is configured as follows:

[0022] Each row of tapered rollers 16 has a respective tapered raceway 11a that tapers axially toward the interior of the bearing unit 10; and

[0023] It has an annular groove 18, which is located on the radially outer side of the center spacer 17, that is, at the axially middle position between the two raceways 11a, where the radial distance between the two raceways 11a and the center spacer 17 is minimized.

[0024] Nevertheless, it must be remembered that the invention can be applied in any case to the opposite situation, namely to a bearing unit 10 having a stationary inner ring 12, 13 and a rotating outer ring 11.

[0025] According to the present invention and also according to Figure 2 As shown, the bearing unit 10 also includes a grease dispensing device 30, which is housed inside the bearing unit 10 at a midpoint between the two rows of tapered rollers 16, and further includes:

[0026] An annular auxiliary storage section 31 is formed inside the outer ring 11 in such a way that it extends from the annular groove 18;

[0027] A radially outer cylindrical rim 32 is fitted inside the slot 18 by snap-fit ​​or pressure to serve as a retaining wall for the storage section 31, and defines the storage section 31 radially inward and toward the axis X; and

[0028] An annular flange wall 33, perpendicular to the axis X and integral with the edge 32, extends radially from the edge 32 toward the axis X by a radial distance equal to the axial width L1 intercepted on both sides of the cylindrical edge 32 itself. The annular flange wall 33 serves as a reinforcing partition for the cylindrical edge 32 and is arranged along the axial centerline of the cylindrical edge 32.

[0029] The cylindrical edge 32 and the annular wall 33 can be made of different materials, but are preferably made of plastic, and have thicknesses S1 and S2 that are substantially similar to each other to optimize their weight without adversely affecting their rigidity. Furthermore, the radial thickness S1 of the cylindrical edge 32 and its total axial width L2 (which is equal to twice the axial width L1 cut off by the annular flange wall 33 on both sides of the edge 32) match the radial depth R and the axial width L3 of the groove 18. This is not only to ensure perfect assembly of the device 30 within the groove 18 by snap-fit ​​engagement or pressure, but also to limit the radial dimension of the dispensing device 30 as much as possible, and especially to limit the axial dimension of the dispensing device 30.

[0030] The flange wall 33 extends radially toward the spacer 17 inside the axial storage portion 25 (defined by the two edges 23 of the retainer 15), but the volume represented by the wall 33 inside the bearing unit 10 is obviously small because the radial length of the wall 33 (as described above, is approximately equal to the axial width L1) makes the wall 33 configured to hardly overlap with the edges 23 in the radial direction, while the thickness S2 of the wall 33 keeps the flange wall 33 well spaced axially from the two edges 23.

[0031] according to Figure 3 and Figure 4 As shown in further detail, the grease dispensing device 30 includes a plurality of through holes 34, which are formed to allow the cylindrical rim 32 to permeate and connect the storage section 25 to the auxiliary storage section 31 via a groove 18. At the start of the life cycle of the bearing unit 10, the auxiliary storage section 31 is also filled with the same lubricant as the storage section 25. During the life cycle of the bearing unit 10, the grease present inside the storage section 25 can migrate between the various components of the bearing unit 10 in a generally random manner, and due to many factors (most of which are uncontrollable), grease maintenance and replenishment operations must be performed. Using the grease dispensing device 30 according to the invention, not only can the amount of grease present at the start of the life cycle of the bearing unit 10 be increased by utilizing the amount contained inside the auxiliary storage section 31, but the grease can also be retained inside the storage section 31 and allowed to flow out during the operation of the bearing unit 10, thereby dispensing the grease in the most controllable possible way. Furthermore, excessive grease filling of the reservoir 25 causes consequent migration of grease between the various components of the bearing unit 10, which is even more random and thus leads to an undesirable increase in the operating temperature of the bearing unit 10. Therefore, by employing the reservoir 31 (i.e., device 10), the initial amount of grease to be introduced into the bearing unit 10 at the start of its life cycle can be better regulated, thereby further extending the life cycle and maintaining the optimal operating performance of the bearing unit 10.

[0032] For the purpose of adjusting the distribution action, and depending on the operating state of the bearing unit 10 and the type of grease, the holes 34 can have different shapes and different distributions along the edge 32.

[0033] In particular, in a preferred embodiment of the device 30 of the present invention, the holes 34 have a circular cross-section, and for each side 32a of the edge 32 defined by the wall 33, the holes 34 are uniformly distributed in two rows 35, the two rows 35 being axially spaced apart from each other by a distance smaller than the diameter or opening size of the holes 34, wherein the holes 34 of one row 35 are angularly spaced from the holes of the other row 35, and the two rows 35 are more compact toward the wall 33 in the axial direction.

[0034] The axial distance between the two rows 35, the diameter of the holes 34, and the possible forms of the holes 34 can themselves present different shapes and forms and different distributions, and the edges 32 and walls 33 can also be made of different materials. According to an embodiment of the invention, although not shown, but easily inferred from the description provided so far, for each portion of the edge 32, there may also be two, three, or more rows of holes 34, and as the number of rows of holes 34 increases, their size may also decrease depending on the grease that can be used with the dispensing device 10.

[0035] In any case, the function of the dispensing device 30 is to retain the grease inside it, that is, to retain the grease inside the auxiliary storage section 31, and to allow the grease to flow out through the edge 32, which serves as a permeable retaining wall, during the operation of the bearing unit 10, so that the grease can be dispensed in the most controllable way.

[0036] In the accompanying drawings, the distributing device is applied to a bearing unit with tapered rollers and is installed at the center between two rows of tapered rollers. However, it should be understood that such a device according to the invention can also be installed on the side relative to one or two rows of tapered rollers.

[0037] Furthermore, although a distribution device in combination with tapered roller bearings has been shown, the same device according to the invention can also be used with other different types of bearings, namely bearings having single or double rows of rolling elements, which are balls, rollers, or other types of rolling elements. More generally, it should be understood that the invention is not limited to the embodiments described and shown herein, but should be considered as examples of units; those skilled in the art can make various changes to the function and construction of the elements described in the examples of embodiments without departing from the scope of the invention as defined in the appended claims and their equivalents.

Claims

1. A rolling bearing unit (10) comprising a radial outer ring (11), two radial inner rings (12, 13), two rows of rolling elements (16) for each radial inner ring (12, 13), and a grease distribution device (30), wherein the radial outer ring (11) is provided with an assembly groove (18), one row of rolling elements (16) is located between the radial outer ring (11) and the corresponding radial inner ring (12, 13), and defines a first internal grease reservoir (25) with the other row of rolling elements (16), the grease distribution device (30) is received within the assembly groove (18) of the radial outer ring (11), and the rolling bearing unit (10) is characterized in that the assembly groove (18) is disposed at an axially intermediate position relative to the two radial inner rings (12, 13), and the grease distribution device (30) comprises: A second grease reservoir (31) is formed inside the radial outer ring (11) and communicates with the first internal grease reservoir (25) via the assembly groove (18); and A permeable retaining wall (32) is accommodated inside the assembly groove (18) to retain the grease inside the second grease reservoir (31) and allow the grease to flow out toward the first internal grease reservoir (25) during operation of the bearing unit (10), thereby distributing the grease in a controllable manner. The grease distribution device (30) includes an annular reinforcing partition (33) which is axially arranged along the centerline of the permeable retaining wall (32); the permeable retaining wall (32) and the annular reinforcing partition (33) each have a thickness (S1, S2) that is substantially similar to each other, so as to optimize their weight without adversely affecting their stiffness.

2. The rolling bearing unit (10) according to claim 1, characterized in that, The permeable retaining wall (32) is defined by a cylindrical rim housed inside the assembly groove (18) and has a plurality of flow elements (34) having a size compatible with the properties of the grease inside the first internal grease storage section (25) and the second grease storage section (31).

3. The rolling bearing unit (10) according to claim 2, characterized in that, The flow element (34) is a through hole distributed along the cylindrical edge.

4. The rolling bearing unit (10) according to claim 3, characterized in that, The through holes are evenly distributed in at least two rows (35) on each half of the cylindrical edge, and the at least two rows (35) are spaced apart from each other in the axial direction by a distance smaller than the size of the opening of the through hole.

5. The rolling bearing unit (10) according to claim 4, characterized in that, The through holes in one row (35) are angularly spaced from those in another row (35), and the two rows (35) are more compactly axially toward the center line of the cylindrical edge.

6. The rolling bearing unit (10) according to claim 2, characterized in that, The thickness (S1) of the cylindrical edge and its total axial width (L2) correspond to the radial depth (R) and axial width (L3) of the assembly groove (18), respectively, so as to ensure the snap-fit ​​assembly of the grease dispensing device (30) inside the assembly groove (18) and limit the radial dimension of the grease dispensing device (30).

7. The rolling bearing unit (10) according to claim 6, characterized in that, The annular reinforcing separator (33) extends radially inside the first internal grease reservoir (25), which is axially defined by two retainers (15) for holding the two rows of rolling elements (16), and the annular reinforcing separator (33) has a radial length that is at most half the axial width (L2) of the cylindrical edge so that the annular reinforcing separator (33) does not overlap with the retainers (15), and the annular reinforcing separator (33) has an axial thickness (S2) that keeps the annular reinforcing separator (33) and the two retainers (15) axially spaced apart.

8. The rolling bearing unit (10) according to claim 3, characterized in that, The through hole is circular in shape.

9. The rolling bearing unit (10) according to claim 2, characterized in that, The thickness (S1) of the cylindrical edge and its total axial width (L2) correspond to the radial depth (R) and axial width (L3) of the assembly groove (18), respectively, so as to ensure the snap-fit ​​assembly of the grease dispensing device (30) inside the assembly groove (18) and limit the axial dimension of the grease dispensing device (30).

Images