Ring with squirrel cage and bearing assembly with rolling elements equipped with the ring

Abstract

The invention relates to an annular ring (3), comprising a contact portion (3-1), a raceway (9) and a cage (3-2) fixed to the contact portion (3-1). The contact portion (3-1) is formed of a first metal material, the cage (3-2) is formed of a second composite material, the second composite material comprising a matrix in which reinforcing fibers are embedded, the perforated portion (13) of the cage (3-2) being attached to an outer surface (8) of the contact portion (3-1). The invention also relates to a bearing assembly (1), the bearing assembly having a rolling element, the rolling element having an outer ring, an inner ring (2) coaxial with the ring, and a plurality of rolling elements (4) accommodated between the raceway (9) of the contact portion (3-1) of the outer ring (3) and the raceway (6) of the inner ring (2).

Description

Technical Field

[0001] The invention relates to a ring with a squirrel cage and a bearing assembly with rolling elements equipped with such a ring. Background Art

[0002] In the aerospace industry, it is known practice to use bearing assemblies with rolling elements that are equipped with a squirrel cage.

[0003] Such a bearing assembly comprises an inner ring provided with an inner raceway, an outer ring provided with an outer raceway and a plurality of rolling elements accommodated between the inner raceway and the outer raceway. The outer ring is further provided with a cage extending axially from the outer ring, the outer ring and the cage being formed integrally. The cage is provided with a flange for fastening to a fixed support, for example by through screws, and must be able to withstand forces. The cage also comprises an axial middle portion with a plurality of circumferentially distributed holes in order to provide the cage with a certain degree of flexibility in order to withstand different vibration modes of the assembly. It is also known practice to provide a lubricating film between the surface of the outer ring and the fixed support, the film being accommodated in a sealing chamber between two seals in order to filter vibrations.

[0004] Now, a compromise has been found by using a material with properties that meet the technical and structural requirements of such a ring for a connection assembly. For example, such a ring can be formed from M50NiL, the raceways additionally being carburized. Summary of the invention

[0005] The present invention aims to overcome the above-mentioned disadvantages.

[0006] More specifically, the invention aims at providing a bearing element having a ring provided with raceways having improved properties and also having a cage with improved properties, without compromises between them, which bearing element is cheaper, easier to produce and has reduced weight.

[0007] The invention relates to an annular ring, comprising a contact portion having an inner surface, an outer surface and a side wall connecting the inner surface and the outer surface, one of the inner surface and the outer surface being provided with a raceway. The ring further comprises a cage fixed to the contact portion, the cage having a perforated portion provided with a plurality of circumferentially distributed holes, and a fastening collar extending from the free end of the perforated portion.

[0008] According to the invention, the contact portion is formed of a first metallic material, the cage is formed of a second composite type material comprising a matrix in which reinforcing fibers are embedded, and the perforated portion of the cage is attached to the outer surface of the contact portion.

[0009] According to the present invention, the contact portion for bearing rolling is made of a material particularly suitable for this function. The material of the contact portion can be selected from a variety of known materials, which have the characteristics of resisting fatigue caused by rolling and friction.

[0010] The cage itself is made of lightweight material, the orientation of the fibers ensures resistance to forces.

[0011] In particular, cages made of such composite materials can be designed so that the transmission of forces favors pure tension or compression of the fibers, without stressing the resin. The composite material thus consists of fiber layers oriented in the direction of the force or at least in a direction close thereto. The fiber structure enables the cage to withstand high tension and / or compression forces while keeping the weight down.

[0012] Another advantage is that it is sufficient to adjust the fiber orientation of the squirrel cage composite to change its Young's modulus without changing the design or dimensions. Therefore, a specific strength can be easily defined and achieved based on a standardized design. The number and orientation of the fibers can also be adjusted locally to strengthen specific areas of the cage and specific vibration modes.

[0013] Finally, the fibers of the composite material have vibration damping properties and cages formed from such composite materials have substantially improved vibration damping properties.

[0014] Another advantage of the invention is that a ring of reduced weight is provided compared to a one-piece ring made of metal. Furthermore, the ring according to the invention is cheaper than a similar ring formed in one piece from metal by performing extensive cutting and machining operations (resulting in a certain loss of material). Furthermore, only the contact portion of reduced size is available for receiving a surface coating or heat treatment.

[0015] According to other advantageous but non-mandatory features of the invention, such a ring may also include the following features, which may be isolated or in any technically feasible combination:

[0016] The first material of the contact part is made of steel, for example: AMS6444, AMS6491 or AMS6278.

[0017] The fibers of the second composite material of the squirrel cage are made of carbon, glass, Kevlar, Vitrane or a combination of different types of fibers.

[0018] The matrix of the second composite material of the cage is epoxy resin, polyamide or phenolic resin.

[0019] The perforated portion of the cage comprises a surface provided with an annular groove in which the contact portion is received.

[0020] The perforated portion of the squirrel cage includes a surface provided with two annular grooves for receiving O-rings to define a space for receiving an oil film to dampen vibrations.

[0021] The fastening portion of the cage comprises at least one through hole for accommodating a fastening screw.

[0022] The surface opposite to the raceway is provided with a recessed area in which the composite material of the cage is received in a fitting manner.

[0023] The recessed area consists of an annular groove.

[0024] The present invention also relates to a bearing assembly with rolling elements, which is provided with a first ring according to any of the aforementioned embodiments, a second ring coaxial with the ring, and a plurality of rolling elements accommodated between the raceway of the contact portion of the first ring and the raceway of the second ring.

[0025] The bearing assembly may also include the following features, used alone or in any technically feasible combination:

[0026] The first ring is the outer ring and the second ring is the inner ring.

[0027] The first ring is the inner ring and the second ring is the outer ring.

[0028] The rolling elements are balls.

[0029] The rolling elements are rollers.

[0030] The rolling elements are held by the cage at regular intervals in the circumferential direction.

[0031] The rolling elements are held regularly spaced apart in the circumferential direction by spacing elements, each spacing element being arranged between two adjacent rolling elements in the circumferential direction.

[0032] The inner ring is made of steel, for example AMS6444, AMS6491 or AMS6278. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will be better understood on reading the following description which is given purely by way of non-limiting example.

[0034] The description is given with reference to the accompanying drawings, in which:

[0035] Figure 1 is a cross-sectional view of a bearing element having rolling elements and provided with a cage according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] Figure 1 A bearing assembly is shown having a rolling element, generally designated 1 and having a centre axis X1 .

[0037] The bearing 1 includes an inner ring 2 , an outer ring 3 and a plurality of rolling elements 4 .

[0038] The inner ring 2 is provided with a substantially cylindrical inner surface 5 , a cylindrical outer surface 6 forming an inner raceway of the rolling elements 4 , and a side wall 7 connecting the inner surface 5 and the outer surface 6 .

[0039] The inner ring 2 is formed of steel, for example AMS6444, AMS6491 or AMS6278.

[0040] The outer ring 3 is provided with a contact portion 3-1 and a cage 3-2 fixed to the portion 3-1.

[0041] The contact portion 3 - 1 includes a substantially cylindrical outer surface 8 , a cylindrical inner surface 9 forming an outer raceway of the rolling element 4 , and a side wall 10 connecting the outer surface 8 and the inner surface 9 .

[0042] The rolling elements 4 are respectively accommodated between the inner raceway 6 of the inner ring 2 and the outer raceway 9 of the contact portion 3-1 of the outer ring 3. Figure 1 In the example shown, the rolling elements 4 are cylindrical rollers, the axes of which are parallel to the central axis X1. Alternatively, the rolling elements may be of other types, such as balls or tapered rollers.

[0043] The outer ring 3 is additionally provided with a cage 3-2 which is fixed to the contact portion 3-1 and extends substantially axially.

[0044] The cage 3 - 2 is provided with a fastening flange 11 extending substantially radially and intended to be securely fastened to a fixed support (not shown), for example by means of threaded screws passing through through holes 12 and housed in corresponding internally threaded openings in said support.

[0045] The cage 3 - 2 also comprises a substantially axial perforated portion 13 having a plurality of circumferentially distributed holes 14 in order to provide the cage 3 - 2 with a certain degree of flexibility in order to withstand different vibration modes of the assembly. Figure 1 In the embodiment shown, the perforated portion 13 comprises two axial portions 13-1, 13-2, each of which is provided with a hole 14, and the diameter of the axial portion 13-2 is greater than the diameter of the axial portion 13-1. The two axial portions 13-1, 13-2 are connected by a folded portion 13-3. The fastening flange 11 extends radially from the free end of the axial portion 13-2 with a larger diameter.

[0046] According to an alternative embodiment (not shown), the perforated portion 13 extends axially without folding, and the fastening portion 11 extends radially from the free end of said perforated portion 13 .

[0047] Advantageously, portion 13-1 of the perforated portion 3-1 comprises an outer surface having two circumferential grooves 15, 16, each of which is capable of accommodating an O-ring seal (not shown), a fluid film being axially arranged between the two seals accommodated in said grooves 15, 16, said film being radially wedged between said outer surface of the squirrel cage 3-2 and the surface of the fixed support (not shown) so as to form a vibration damping device.

[0048] According to the present invention, the contact portion 3 - 1 is formed of a first metal material, and the cage 3 - 2 is formed of a second composite material.

[0049] The contact portion 3-1 is advantageously made of steel, for example: AMS6444, AMS6491 or AMS6278. The contact portion can be obtained by any suitable method, in particular by molding and machining a metal material, or by 3D printing. The raceway 9 may have a surface coating, in particular in order to reduce the rolling friction coefficient. The contact portion 3-1 may also be subjected to a heat treatment to optimize its hardness.

[0050] The cage 3 - 2 is made of a composite material including a matrix in which reinforcing fibers are embedded.

[0051] The fiber of the composite material of the squirrel cage 3-2 is made of carbon, glass, Kevlar fiber, Vectran fiber or a combination of different types of fibers. The composite material matrix of the squirrel cage 3-2 is epoxy resin, polyamide or phenolic resin.

[0052] The perforated portion 13 of the cage 3-2 is connected to the outer surface 8 of said contact portion 3-1. According to one embodiment (not shown), the portion 13-1 of the perforated portion 13 comprises a surface diametrically opposite the grooves 15, 16 and is provided with a circumferential groove in which the contact portion 3-1 is accommodated.

[0053] Advantageously, the outer surface 8 of the contact part is provided with an annular groove 17, the composite material of the cage 3-2 externally surrounding the outer surface 8 of the contact part 3-1 and protruding from there in the direction of said surface 8, the radial protrusions being received in a fitting manner in said annular groove 17. The fixed connection between the cage 3-2 and the contact part 3-1 is thus strengthened by increasing the contact area between the composite material and the metal, thereby increasing the bonding effect between these parts. In addition, the radial protrusions create a resistance release, thereby forming a means for retaining the two parts 3-1, 3-2 in both axial directions.

[0054] The annular groove 17 is Figure 1 The axial cross section is shown as a rectangle. Optionally, the annular groove may have any other suitable shape, such as a dovetail or a triangle. According to another alternative, the outer surface 8 is provided with at least one non-annular recessed area.

[0055] The composite material of the cage 3-2 is molded to cover the outer surface 8 of the contact part 3-1, in particular by filling the grooves 17. After this method step, the composite material is firmly adhered to the contact part 3-2. In this way, a non-detachable outer ring 3 assembly is obtained, such as Figure 1 shown.

[0056] Furthermore, the technical features of the various embodiments may be combined with one another completely and only for some of them. Thus, the bearing assembly may be adjusted in terms of cost, performance and simplicity of implementation.

Claims

1. An annular ring (3) comprising: A contact portion (3-1) having a radial inner surface (9), a radial outer surface (8) defining an annular groove (17), and a side wall (10) connecting the radial inner surface (9) and the radial outer surface (8), wherein the radial inner surface is provided with a raceway, and a cage (3-2) located on the radial outer surface (8) of the contact portion (3-1) and engaging the annular groove (17), the cage (3-2) axially overlapping the radial outer surface (8) of the contact portion (3-1) but not overlapping the side wall (10) of the contact portion (3-1), the cage (3-2) having a perforated portion (13) provided with a plurality of circumferentially distributed holes (14) and a fastening flange (11) extending from the free end of the perforated portion (13), It is characterized in that The contact portion (3-1) is formed of a metallic material, the cage (3-2) is formed of a composite material including a matrix in which reinforcing fibers are embedded, and the perforated portion (13) of the cage (3-2) is axially spaced apart from the contact portion (3-1).

2. The annular ring according to claim 1, wherein the metal material of the contact portion (3-1) is made of steel.

3. An annular ring according to claim 1 or 2, wherein the fibers of the composite material of the cage (3-2) are made of carbon fibers, glass fibers, Kevlar fibers, Viktoron fibers or a combination of the aforementioned different types of fibers.

4. An annular ring according to claim 1 or 2, wherein the matrix of the composite material of the cage (3-2) is epoxy resin, polyamide or phenolic resin.

5. An annular ring according to claim 1 or 2, wherein the perforated portion (13) of the squirrel cage (3-2) axially overlapping the contact portion (3-1) includes a face provided with a radial protrusion configured to engage in an annular groove for accommodating the contact portion (3-1).

6. An annular ring according to claim 1 or 2, wherein the perforated portion (13) of the squirrel cage (3-2) axially overlapping the contact portion (3-1) comprises a face provided with two circumferential grooves (15, 16), the annular grooves being used to receive an O-ring seal so as to define a space for receiving an oil film to dampen vibrations.

7. An annular ring according to claim 1 or 2, wherein the fastening flange (11) of the cage (3-2) comprises at least one through hole (12) for accommodating a fastening screw.

8. A bearing assembly (1), comprising: An annular ring (3) according to any one of the preceding claims, as a first ring, a second ring (2) coaxial with said first ring, and A plurality of rolling elements (4) are accommodated between the raceway of the contact portion (3-1) of the first ring and the raceway (6) of the second ring (2).

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