Thin-walled bearing unit

Abstract

A thin-walled bearing unit (10) for a multi-wire machine, the bearing unit having a central axis of rotation (A) and having an inner ring (20) and a flanged rotatable outer ring (30), the inner ring (20) and the outer ring (30) defining therebetween a cylindrical cavity (90) for each rolling element (40); the inner ring (20) has an outer raceway (22) with an intermediate circumferential groove (23) containing grease for keeping the raceway (22) lubricated, and the bearing unit (10) also has a hydraulic network (60) for distributing grease to lubricate the cavity (90), which hydraulic network (60) is provided with at least one axial duct (61) and associated radial ducts (62), the axial duct (61) passing through the inner ring (20), and the radial ducts (62) passing through the inner ring (20). A radial duct (62) is formed in the inner ring (20) between the axial duct (61) and the circumferential groove (23) of the outer raceway (22).

Description

Technical Field

[0001] The present invention relates to a thin-walled bearing unit (thin section bearing unit).

[0002] In particular, the invention relates to a thin-walled bearing unit for multiwire machines, to which reference will be made in the present description without prejudice to its general applicability. Background Art

[0003] In a multi-wire machine, blocks of stone material (such as stone, marble, concrete, etc.) are cut into slabs by the action of diamond cutting wires, which are positioned parallel to one another along a cutting path and are pulled along this path by tensioner pulleys. For the production of slabs of relatively small thickness, the tensioner pulleys are assembled as a set axially one beside the other on a common support shaft and are made rotatable relative to the support shaft by the insertion of corresponding thin-walled bearing units.

[0004] Therefore, the known thin-walled bearing units for multi-line machines are also mounted in a group one beside the other along a corresponding common central rotational axis (defined by the support shaft) and, despite the fact that the thin-walled bearing units each have a rather large outer diameter, they must have a very small axial thickness in order to allow the tensioning wheels to be mounted axially as close to each other as possible, whereas the combination of large diameter and small axial thickness requires particularly complex technical solutions in order to always ensure high performance.

[0005] The bearing unit consists of:

[0006] - corresponding inner rings, which are stationary, are arranged adjacent to each other in the axial direction;

[0007] - respective outer rings, rotatable, having an axial dimension slightly smaller than that of the associated inner ring, so as to be able to rotate independently of each other and to allow independent rotation of the associated tensioner; and

[0008] - Corresponding sealing shields ( / protective members / protective covers) are arranged on both sides of the bearing unit opposite in the axial direction and between the relevant inner ring and the relevant outer ring, so as to not only prevent contaminating materials (for example, water mixed with stone dust) from entering the bearing unit, but also prevent internal grease from diffusing to the outside.

[0009] Each outer ring has a respective supporting flange connected to the associated wheel, while each inner ring is laterally delimited by respective annular surfaces which are placed in direct contact with the annular surfaces of the inner ring of the axially adjacent bearing unit.

[0010] The high level of contamination in the working environment of the above-mentioned bearing units, combined with the methods used to treat the stone and the poor heat dissipation due to the fact that the bearing units are mounted closely together as a set, means that frequent maintenance is necessary to extend the service life of the bearing units. During these maintenance operations, the bearing units undergo a thorough deep cleaning, despite the presence of the sealing shield, as well as an almost complete reconditioning of the grease present in the bearing units, since their service life also depends very directly on the purity of this grease.

[0011] Since such maintenance largely involves disassembly of both the tensioning wheel and the bearing unit, it is actually very detrimental to the production efficiency of the associated multi-line machine. Summary of the invention

[0012] The object of the present invention is to produce a thin-walled bearing unit which makes it possible to extend its service life without requiring particular dismantling or disassembly, or to reduce the frequency of the above-mentioned maintenance, which is entirely to the advantage of the production efficiency of the associated multi-line machine.

[0013] The thin-walled bearing unit according to the invention has the features set out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will now be described with reference to the accompanying drawings showing non-limiting embodiments of the invention, in which:

[0015] - Figure 1 is a side view of a preferred embodiment of a thin-walled bearing unit of the present invention;

[0016] - Figure 2 and Figure 3 It is along Figure 1 The cross sections of line II-II and line III-III in FIG.

[0017] - Figure 4 Shows the use of Figure 1 A set of thin-walled bearing units produced by. DETAILED DESCRIPTION

[0018] Reference Figure 1 , reference numeral 10 generally denotes a bearing unit having a thin section, so that the bearing unit takes up very little space in the axial direction, such as Figure 4 As shown, the bearing unit can be installed together with other identical bearing units 10 as a group (set) 100 of bearing units 10, wherein the group 100 can include thirty to one hundred or even one hundred and fifteen bearing units 10 placed side by side along the corresponding common central rotation axis A.

[0019] The thin-walled bearing unit 10 of the invention can be advantageously used in multiwire machines, to which the following description will refer by way of example, without prejudice to its general applicability. In such multiwire machines, blocks of stone material are cut into slabs by the action of diamond cutting wires which are positioned parallel to one another along the blocks and which are pulled across the blocks by tensioner pulleys (not shown). To produce these slabs, the tensioner pulleys are assembled in a set axially one beside the other on a common support shaft (not shown) defining a central axis A and are made rotatable relative to the support shaft by the interposition of the respective bearing unit 10.

[0020] like Figure 2 As shown, the bearing unit 10 comprises:

[0021] an inner ring 20 , which is stationary, mounted on a stationary shaft and delimited in the axial direction by a corresponding annular surface 21 transverse to the axis A;

[0022] a flanged outer ring 30 , which is rotatable, has an axial thickness S2 of a smaller dimension than the axial thickness S1 of the inner ring 20 , and defines together with the inner ring 20 a cylindrical cavity 90 ;

[0023] a plurality of rolling elements (preferably balls) 40 arranged inside the cavity 90 and between the inner ring 20 and the outer ring 30 so as to allow the inner ring 20 and the outer ring 30 to rotate relative to each other about the axis A; and

[0024] - Two sealing shields 50 are arranged on opposite sides of the bearing unit 10 in the axial direction and between the inner ring 20 and the outer ring 30, so as to not only prevent contaminating materials (for example, water mixed with stone dust) from entering the cavity 90 of the bearing unit 10, but also prevent the grease contained in the cavity 90 from diffusing to the outside.

[0025] The inner ring 20 and the outer ring 30 are respectively provided with an outer raceway 22 and an inner raceway 32, which face each other in the radial direction and face the cavity 90 (the rolling element 40 can roll in the cavity 90), and the outer ring 30 also has a support flange 31, which extends radially outward from the outer ring 30 in a direction transverse to the axis A and is connected to the relevant wheel (pulley) of the multi-line machine.

[0026] The inner ring 20 is delimited radially inside by a cylindrical surface 24 coaxial with the axis A and orthogonal to two annular surfaces 21 placed in direct contact with the annular surfaces 21 of the inner ring 20 of the axially adjacent bearing unit 10 when the bearing unit 10 is mounted as a set together with other identical bearing units 10. In the bearing unit 10 according to the invention, the ratio between the inner diameter of the surface 24 and the axial thickness S1 of the inner ring 20 ranges from a minimum value of 8 to a maximum value of 12. The inner ring 20 also has a circumferential groove 23 on the outer raceway 22, which divides the raceway 22 into two annular portions 22' which are mirror images of each other with respect to a symmetry plane P of the rolling elements 40 perpendicular to the axis A.

[0027] The circumferential groove 23 duly contains grease for keeping the raceway 22 lubricated and, precisely, the bearing unit 10 further comprises a hydraulic network 60 for distributing the grease for the purpose of topping up the grease so as to extend the service life of the bearing unit 10 without having to remove and / or disassemble the bearing unit 10.

[0028] The hydraulic network 60 makes it possible to distribute fresh grease inside the bearing unit 10 and comprises at least one axial duct 61 and an associated radial duct 62, wherein the axial duct 61 passes through the inner ring 20 parallel to the axis A and the radial duct 62 is formed in the inner ring 20 between the duct 61 and the cylindrical bottom 25 of the circumferential groove 23.

[0029] The axial conduit 61 is formed between the circumferential groove 23 and the cylindrical surface 24 at a position radially closer to the cylindrical surface 24 than the cylindrical bottom 25 of the circumferential groove 23 so as to avoid affecting the performance or characteristics of the bearing unit 10 in any way, and the axial conduit 61 is also formed to pass through the two surfaces 21 to connect the two axially opposite sides of the bearing unit 10 to each other. The axial conduit 61 and the radial conduit 62 have a diameter sized between 1.5 mm and 1.75 mm so as to allow sufficient grease (as explained more fully below) injected therein using a manual pump or by means of an automatic system with a timer ( / on the timer) to flow into the cavity 90 from the outside of the bearing unit 10.

[0030] As described above, the thin-walled bearing unit 10 has a relatively large outer diameter, so in order to help distribute the injected grease as evenly as possible, the hydraulic network 60 includes up to eight pipes 61 and one pipe 62 for each pipe 61, the eight pipes 61 are evenly distributed around the axis A, and when there are eight pipes 61 as in the embodiment shown here, the eight pipes 61 are arranged at 45° from one another.

[0031] Reference Figure 1 and Figure 2 In the preferred embodiment shown, all eight pipes 61 are parallel to the axis A and, like all eight pipes 62, have a diameter between 1.5 mm and 1.75 mm to ensure that sufficient grease injected therein can flow from the outside of the bearing unit 10 into the cavity 90 and flow around the entire circumference of the circumferential groove 23.

[0032] As with the number of conduits 61 and 62 selected for each bearing unit 10, the diameter selected for the conduits 61 and 62 will depend substantially on the operating conditions, the type of grease preferred for those operating conditions, and will also depend substantially on the number of bearing units 10 in each group 100.

[0033] This is because, as repeatedly emphasized above, the bearing units 10 according to the invention are intended to always be mounted together with other identical bearing units 10 in groups 100 containing thirty to one hundred or even one hundred and fifteen bearing units 10 and, in this type of mounting, in order to ensure that even the bearing units 10 positioned towards the center of the group 100 receive the necessary amount of grease, it is essential that the duct 61 of each bearing unit 10 is perfectly aligned with the duct 61 of the immediately adjacent bearing unit 10.

[0034] For this reason, Figure 3 As shown, the bearing unit 10 comprises one or more pairs 70 of blind centering holes 71, which are parallel to the axis A and extend from the surface 21 towards the inside of the inner ring 20. The blind holes 71 in each pair 70 of blind holes 71 are aligned with each other and have a diameter larger than the diameter of the pipe 61, and preferably, have a diameter equal to 2.5 mm. The pairs 70 of blind holes 71 are also positioned radially closer to the cylindrical surface 24 than the raceway 22, however, given the size of the diameter of the holes 71, they have a limited axial depth, preferably not exceeding 4 mm, so that they do not overlap axially with the raceway 22 in the axial direction, so as to avoid affecting its performance or characteristics in any way.

[0035] For each pair 70 of blind holes 71, the bearing unit 10 further includes a peg 72 having an axial length not exceeding twice the axial depth of the hole 71 and inserted into axially opposite blind holes 71 of the two bearing units 10 when the two bearing units 10 are placed side by side to fully align all pipes 61.

[0036] Again in view of the fact that the thin-walled bearing unit 10 has a considerable outer diameter, and since the hydraulic network 60 comprises up to eight pipes 61, the bearing unit 10 may also comprise up to eight pairs 70 of centering blind holes 71, which are evenly distributed around the axis A and, when there are eight pairs of centering blind holes 71 as in the embodiment shown here, are configured to be at 45° to each other in angular positions alternating with the pipes 61.

[0037] Now refer to Figure 4, note that although the hydraulic network 60 does include at least one axial conduit 61 and at least one radial conduit 62 for each bearing unit 10 in the group 100, the hydraulic network 60 includes all axial conduits 61 and all radial conduits 62 of all bearing units 10 in the group 100, wherein the axial conduits 61 of the inner bearing units 10 are connected to the axial conduits 61 of the adjacent bearing units 10, while the conduits 61 of the axially outer bearing units 10 will be connected to a manual pump for manually injecting grease into the hydraulic network 60, or to an automatic system on a timer suitable for automatically injecting grease into the hydraulic network 60.

[0038] Based on the proper dimensioning of the diameters of the pipes 61 and 62 within the indicated ranges, the larger the size of the group 100 of bearing units 10, the more care will have to be taken to be able to send the right amount of grease to said bearing unit 10, even having to consider greases with a specific viscosity or with a specific injection temperature so that the grease has the viscosity required and allows the grease to flow from one pipe 61 to the next until they reach the cavity 90 of the bearing unit 10 axially furthestaway from the outside.

[0039] It is clear from the above that, with the bearing unit 10 of the present invention, it will no longer be necessary to perform frequent maintenance, since relubrication of the bearing unit 10 can be performed directly without shutting down ( / shutting down) the multi-line machine involved, which is entirely beneficial to both the productivity of the multi-line machine and the service life of the bearing unit 10.

[0040] In addition to the embodiments of the present invention as described above, it should be understood that there are many other variations. It should also be understood that the embodiments are examples only and do not limit the subject matter of the present invention, the application of the present invention or the feasible configuration of the present invention. In contrast, although the above description enables those skilled in the art to apply the present invention according to at least one exemplary configuration of the present invention, it should be understood that many variations of the described components can be envisioned without therefore departing from the subject matter of the present invention as defined in the appended claims as interpreted literally and / or according to its legal equivalents.

Claims

1. A thin-walled bearing unit (10) for a multi-line machine, the bearing unit having a central axis of rotation (A) and comprising: - a fixed inner ring (20) delimited axially by a corresponding annular surface (21) transverse to said axis (A) and further delimited radially on the inside by a cylindrical surface (24) coaxial with said axis (A) and radially on the outside by an outer raceway (22); - a rotatable outer ring (30) with a flange, the axial dimension of the outer ring (30) being smaller than the axial dimension of the inner ring (20), and the outer ring (30) and the inner ring (20) together define a cylindrical cavity (90); and - a plurality of rolling elements (40) arranged inside the cavity (90) and between the inner ring (20) and the outer ring (30) so as to allow the inner ring (20) and the outer ring (30) to rotate relative to each other around the axis (A); The thin-walled bearing unit (10) is characterized in that the thin-walled bearing unit (10) includes a hydraulic network (60) for distributing grease for lubricating the cavity (90), and further includes at least one axial pipe (61) and an associated radial pipe (62), wherein the axial pipe (61) passes through the inner ring (20) parallel to the axis (A), and the radial pipe (62) is formed in the inner ring (20) between the axial pipe (61) and the outer raceway (22).

2. The thin-walled bearing unit according to claim 1, characterized in that: The axial pipe (61) is formed between the two surfaces (21) so as to connect the two axially opposite sides of the bearing unit (10) to each other, and the axial pipe (61) is formed between the outer raceway (22) and the cylindrical surface (24) at a position closer to the cylindrical surface (24) in the radial direction than the outer raceway (22) so as to avoid affecting the performance or characteristics of the bearing unit (10).

3. The thin-walled bearing unit according to claim 2, characterized in that: The outer raceway (22) comprises a circumferential groove (23), which divides the outer raceway (22) into two annular parts (22'), the two annular parts (22') being mirror images of each other about a symmetry plane (P) of the rolling element (40) perpendicular to the axis (A), and the circumferential groove (23) contains grease for keeping the raceway (22) lubricated: the radial duct (62) leads into the groove (23) through the bottom (25) of the groove (23) to replenish the grease and extend the service life of the bearing unit (10).

4. The thin-walled bearing unit according to claim 3, characterized in that: The hydraulic network (60) for distributing the grease comprises up to eight axial ducts (61) and one radial duct (62) for each axial duct (61), wherein the axial ducts (61) are evenly distributed around the axis (A) and when there are eight axial ducts (61), the eight axial ducts (61) are arranged at 45° to each other.

5. The thin-walled bearing unit according to claim 4, characterized in that: The thin-walled bearing unit occupies a very small space in the axial direction, so that the thin-walled bearing unit can be installed together with other identical thin-walled bearing units (10) as a group (100) of thin-walled bearing units (10), wherein the group (100) includes a predetermined number of thin-walled bearing units (10), the predetermined number being in the range of a minimum of thirty to a maximum of at least one hundred and fifteen, and wherein the thin-walled bearing units (10) are assembled side by side along the axis (A) and the associated annular surfaces (21) of the central inner ring (20) are placed in direct contact with each other.

6. The thin-walled bearing unit according to claim 5, characterized in that: The hydraulic network (60) comprises all axial pipes (61) and all radial pipes (62) of all bearing units (10) in the group (100), wherein the axial pipes (61) of the thin-walled bearing units (10) inside the group (100) are connected to the axial pipes (61) of the adjacent thin-walled bearing units (10), while the pipes (61) of the axially external thin-walled bearing units (10) are connected to a device for injecting grease into the hydraulic network (60).

7. The thin-walled bearing unit according to claim 6, characterized in that: The thin-walled bearing unit comprises a centering component (70, 71, 72), which is used to axially center the pipe (61) of the hydraulic network (60) of the group (100); the centering component (70, 71, 72) comprises: one or more pairs (70) of centering blind holes (71), parallel to the axis (A) and extending from the surface (21) toward the inside of the inner ring (20); and a peg (72) for each pair (70) of centering blind holes (71), the axial length of the peg (72) not exceeding twice the axial depth of the hole (71).

8. The thin-walled bearing unit according to claim 7, characterized in that: The centering blind hole (71) has a limited axial depth so that the centering blind hole (71) does not overlap with the raceway (22) in the axial direction, so as to avoid affecting the performance or characteristics of the raceway (22) in any way.

9. The thin-walled bearing unit according to claim 1, characterized in that: The outer ring (30) has a supporting flange (31) which extends radially outwards from the outer ring (30) in a direction transverse to the axis (A) and is connected to a corresponding wheel of the multi-wire machine.

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