Rings for connecting elements, connecting elements, and corresponding manufacturing methods

Abstract

The ring (6) for connecting element (2) includes a contact portion (52) intended to mate with a contact surface (14) of another ring (4) and a fastening portion (32) intended to be fixed to a support. The contact portion (52) is made of a first metal material, and the fastening portion (32) is made of a second metal material. The hardness of the first material is strictly greater than the hardness of the second material, and the toughness of the second material is strictly greater than the toughness of the first material. The contact portion (52) and the fastening portion (32) are integrally formed.

Description

Technical Field

[0001] The present invention relates to a connecting element, a ring intended to be incorporated into such a connecting element, and a method for manufacturing such a ring. Background Technology

[0002] In the aerospace industry, rolling element bearings are known to be used in a variety of applications, such as enabling pivoting mechanical connections on aircraft engine shafts. Typically, rolling element bearings used for such applications have very complex shapes.

[0003] Typically, a ring fitted onto such a rolling element bearing includes: a contact portion designed to contact the rolling element of the bearing; and a fastening portion through which the ring can be fastened to a support or engine shaft. For example, some rolling element bearings designed for use in aircraft engines include an outer ring with a collar or squirrel cage fastening portion.

[0004] Under these conditions, the ring must be able to withstand two different types of loads: the contact portion must have sufficient hardness to create an effective raceway for the rolling elements, while the fastening portion must have sufficient structural fatigue strength to reliably fasten the ring to the support.

[0005] To accommodate these two types of loads, it has been recommended to select materials that represent a good trade-off between the two types of loads. For example, the ring can be made of M50NiL steel, and the raceway surfaces of the contact portions can be surface hardened.

[0006] However, this solution is not entirely satisfactory. First, the raceway surface made of surface-hardened M50NiL has lower hardness compared to other types of steel. Furthermore, the process of surface-hardening the raceway surfaces at the contact points is expensive. Additionally, the mass of the fastening parts is relatively high compared to using lighter materials to achieve equivalent fatigue performance. Summary of the Invention

[0007] The present invention aims to overcome the above-mentioned disadvantages.

[0008] More specifically, the present invention aims to improve the hardness and structural fatigue strength of the contact portion and fastening portion of the ring of the connecting assembly.

[0009] Therefore, this document proposes a ring for connecting elements, including a contact portion intended to mate with a contact surface of another ring and a fastening portion intended to be fixed to a support.

[0010] According to a general feature of the ring, the contact part is made of a first metal material, the fastening part is made of a second metal material, the hardness of the first material is strictly greater than the hardness of the second material, the toughness of the second material is strictly greater than the toughness of the first material, and the contact part and the fastening part are made as one piece.

[0011] The hardness of the primary material allows for better contact fatigue strength at the contact points. Higher toughness enables the fastening components to exhibit good structural fatigue strength. Therefore, the geometry of this ring can be optimized in part by leveraging its mechanical properties, resulting in a lighter and more reliable ring than those made from a single material. Furthermore, one-piece manufacturing eliminates the need for solder beads between the contact and welded portions, reducing manufacturing costs and increasing reliability.

[0012] In this application, the phrase "one-piece manufacturing" should be understood as consisting of two parts that form a part, since the two parts are formed as a single piece in the same forming process. Therefore, a part consisting of two parts made into a single piece is not an assembly of two parts formed separately and then joined together in a subsequent assembly process.

[0013] Preferably, the contact portion and the fastening portion are integrated by sintering metal powder.

[0014] Advantageously, the fastening portion includes a retainer, which includes radial fastening edges and a basic axial portion provided with a plurality of circumferentially distributed windows.

[0015] On the other hand, a connecting element designed to be incorporated into an aircraft is proposed, comprising a first ring and a second ring, the first and second rings being mounted to pivot relative to each other, the first ring being a ring as defined above.

[0016] According to one embodiment, the contact portion includes a contact surface, and the connecting element includes at least one row of rolling elements located between the contact surfaces of the first ring and the second ring.

[0017] On the other hand, a method for manufacturing a ring for a connecting element as defined above is proposed, comprising, in the following order: storing a first metal powder in a housing; storing a second metal powder in a housing, the second powder being different from the first powder; the method further comprising sintering the powder stored in the housing to integrally form the contact portion and the fastening portion of the ring.

[0018] It is also possible to provide a third metal powder stored in the housing, which is different from the first and second powders. The powder stored in the housing is sintered to form an additional part of the ring integrally with the contact part and the fastening part.

[0019] This embodiment can in particular form a transition portion between the contact portion and the fastening portion of the ring.

[0020] According to one embodiment, the method includes placing a spacer device in a housing before storing a first metal powder, with the powder stored in the housing arranged around the spacer device.

[0021] Such embodiments allow for the formation of hollow preforms, thereby reducing the number of machining operations required to obtain the ring.

[0022] According to another embodiment, the sintering powder includes spark plasma sintering.

[0023] According to one embodiment, the sintered powder includes hot isostatic pressing.

[0024] Heat treatment and / or machining steps can also be provided after sintering the powder. Attached Figure Description

[0025] Other objects, features, and advantages of the invention will become more apparent from the following description, which is provided by way of non-limiting example only and with reference to the accompanying drawings, wherein:

[0026] Figure 1 A connecting element according to one aspect of the present invention is schematically shown.

[0027] Figure 2 An apparatus for fabricating such a ring by spark plasma sintering is schematically shown.

[0028] Figure 3 The illustration shows the process of manufacturing. Figure 1 The method of connecting the ring of the element, and

[0029] Figure 4 The cross-sectional view shows that in Figure 3 The preform obtained during the process of the method. Detailed Implementation

[0030] Figure 1 Connecting element 2 is shown. Connecting element 2 is a component of a rolling element bearing. Connecting element 2 is intended to be integrated into an aircraft. In particular, connecting element 2 is intended to guide a pivotal mechanical connection between the engine shaft and a support or housing of an aircraft engine (not shown). However, different applications of connecting element 2 are conceivable without departing from the scope of the invention.

[0031] The connecting element 2 includes an inner ring 4 and an outer ring 6. In this case, the inner ring 4 is intended to be fixed to the engine shaft (not shown) of the aircraft engine, and the outer ring 6 is intended to be fixed to a support member (not shown) of the aircraft engine.

[0032] An orthogonal vector basis 8, identical to outer ring 6, is defined. Basis 8 consists of vectors X, Y, and Z.

[0033] The shapes of rings 4 and 6 are those of cylinders rotated about a shared axis of rotation 10. Axis 10 is parallel to vector X.

[0034] In this application, unless otherwise stated, the term "cylindrical surface" refers to a surface formed by a set of parallel straight lines resting on a closed plane curve.

[0035] In this application, unless otherwise stated, the terms “axial,” “axially,” “radial,” and “radially” should be understood in relation to the axis of rotation 10.

[0036] The inner ring 4 has a generally cylindrical inner surface 12, a cylindrical outer surface 14 forming an inner raceway, and a sidewall 16 connecting the inner surface 12 and the outer surface 14.

[0037] The inner ring 4 is made of steel, such as M50.

[0038] The outer ring 6 has a basic cylindrical outer surface 18, a cylindrical inner surface 20 forming an outer raceway, and a sidewall 22 connecting the outer surface 18 and the inner surface 20.

[0039] Advantageously, the outer surface 18 includes two circumferential grooves 24, 26, each capable of accommodating a sealing section (not shown). A fluid membrane is axially disposed between the two sections accommodated in the grooves 24, 26, and the membrane is radially confined between the outer surface 18 and the fixed support surface (not shown), thereby forming a vibration damping device.

[0040] The connecting element 2 includes a plurality of rolling elements 28 housed between raceways formed by the outer surface 14 and the inner surface 20. With the rolling elements 28 arranged in this manner, the ring 4 is able to pivot about the axis 10 relative to the ring 6. The rolling elements 28 are held in the radial and tangential directions by a cage 30. In the example shown, the rolling elements 28 are cylindrical rollers with their axes parallel to the axis 10. Alternatively, the rolling elements can be of another type, such as balls or tapered rollers. Similarly, it is conceivable that the connecting element 2 does not have rolling elements, such as a sliding bearing, without departing from the scope of the invention.

[0041] The outer ring 6 has a cage-shaped retainer 32 extending axially from the sidewall 22 of the outer ring 6.

[0042] The cage 32 is provided with a fastening edge 34 that extends substantially radially and is intended to be securely fastened to a fixed support or frame (not shown), for example by a screw passing through the through hole 36 and received in a corresponding threaded hole in the support.

[0043] The cage 32 includes a generally axial intermediate portion 38 having a plurality of windows 40 circumferentially distributed around axis 10. The windows 40 are designed to provide a degree of flexibility to the cage 32 to withstand various vibration modes of the assembly. According to the illustrated embodiment, the intermediate portion 38 includes two axial portions 42, 44, each provided with a window 40. The diameter of the axial portion 44 is larger than the diameter of the axial portion 42. The two axial portions 42, 44 are connected by a folding portion 46. The fastening edge 34 includes an outer portion 48 extending radially outward from the free end of the axial portion 44 and an inner portion 50 extending radially inward from the free end of the axial portion 44.

[0044] According to the present invention, the outer ring 6 is made of two different materials. The outer ring 6 includes a contact portion 52, which is configured to roll contact with the rolling element 28 and is formed of the first material. Therefore, in this exemplary embodiment, the contact portion 52 engages with the outer surface of the inner ring by inserting into the rolling element 28. As mentioned above, as a variation, a connecting element without a rolling element can be provided. In this case, the contact portion 52 engages directly with the outer surface of the inner ring.

[0045] The outer ring 6 also includes a rat cage 32 forming a fastening portion and made of a second material different from the first material.

[0046] The contact portion 52 includes an outer surface 18, an inner surface 20, and a sidewall 22. The contact portion 52 is made of a material selected for its contact fatigue characteristics, and its hardness is strictly greater than that of the second material. Therefore, the contact portion 52 is made of a specific material to provide direct rolling element bearing support for the elements of the rolling element bearing 28. In the example shown, the first material is steel selected from the following list: T15, AMS6560, T1 (Z80 WCrV18.4.1), M62, M50, ASP2055.

[0047] The cage 32 is made of a material with an elasticity strictly greater than that of the first material. Therefore, the cage 32 is made of a specific material to withstand forces and vibrations. In the example shown, the second material is selected from the following list: titanium alloys, aluminum alloys, steel, such as low-carbon or medium-carbon steel, 32CVD13, INCONEL 718.

[0048] Figure 2 Manufacturing apparatus 100 is schematically shown. Apparatus 100 is intended for manufacturing rings such as the outer ring 6 of connecting element 2.

[0049] The device 100 includes a pulse generator 102, an upper mold 104, and a lower mold 106. The generator 102 is capable of generating current and is electrically connected to the molds 104 and 106. The molds 104 and 106 are made of a conductive material. For example, the molds 104 and 106 are made of graphite. Alternatively, the molds 104 and 106 may accommodate conductive elements extending along their entire height.

[0050] The apparatus 100 also includes a hollow cylinder 108. The shape of the cylinder 108 is rotatable about a vertical axis (not shown). The hollow cylinder 108 includes a cylindrical inner surface whose shape matches the cylindrical surface of the lower end 110 of the upper mold 104 and the cylindrical surface of the upper end 112 of the lower mold 106. Due to these matching shapes, the interior of the cylinder 108, together with the ends of the molds 104 and 106, defines the outer shell 114. The cylinder 108 includes a bottom wall 109 through which the cylinder 108 can be held vertically relative to the mold 106, and through which it can be moved when the cylinder 108 is filled with powder.

[0051] The device 100 includes a cylinder 116. The shape of the cylinder 116 is rotatable about a vertical axis (not shown). The cylinder 116 is arranged in a housing 114 such that its axis of rotation substantially coincides with the axis of rotation of the cylinder 108. The cylinder 116 is shorter than the vertical distance between the molds 104 and 106, allowing the molds to be assembled together when compacting powder.

[0052] refer to Figure 3 The following describes the use of Figure 2 The manufacturing apparatus 100 implements a method for manufacturing the outer ring 6. Although Figure 3 The method shown is used to manufacture the outer ring 6, but it is conceivable to use this method to produce another ring, such as the inner ring 4, without departing from the scope of the invention.

[0053] In the initial state of the method, cylinders 108 and 116 are arranged above the upper end of the lower mold 106. Therefore, the outer shell 114 is defined by cylinders 108 and the lower mold 106 and can be accessed from above.

[0054] The method includes applying a first metal powder 118 (see...) Figure 2 The first step E01 is stored in the housing 114. The first powder 118 is intended to be used to form the contact portion 52 of the outer ring 6. For this purpose, the first powder 118 is adapted to form a first material constituting the contact portion 52.

[0055] The method includes applying a second metal powder 120 (see...) Figure 2The second step E02 is stored in the outer casing 114. The second powder 120 is intended for use in forming the rat cage 32 of the outer ring 6. For this purpose, the second powder 120 is intended for use in forming the second material constituting the rat cage 32.

[0056] The first powder 118 and the second powder 120 are different. More specifically, the first powder 118 is intended to form a steel that is harder than the material formed by the second powder 120, and the second powder 120 is intended to form a metal that has greater structural fatigue strength than the material formed by the first powder 118.

[0057] Due to the sequence of steps E01 and E02, the first powder 118 is vertically positioned between the lower mold 106 and the second powder 120.

[0058] The method includes a third step E03 of positioning the upper mold 104. Step E03 includes placing the lower end of the mold 104 inside the cylinder 108 and vertically adjacent to the cylinder 116. Therefore, the second powder 120 is vertically positioned between the upper mold 104 and the first powder 118.

[0059] The method includes a fourth step, E04, of sintering powders 118 and 120. In this case, step E04 includes spark plasma sintering of powders 118 and 120. Spark plasma sintering is also known as the abbreviation SPS.

[0060] During step E04, pulse generator 102 emits multiple current pulses. These pulses are transmitted to powders 118 and 120 via molds 104 and 106. Joule heating causes a significant temperature increase in powders 118 and 120 until they fuse. The result of step E04 is a preform 122, which includes a lower portion 124 corresponding to the sintered powder 118 and an upper portion 126 corresponding to the sintered powder 120. Figure 4 Preform 122 is shown. Therefore, portion 124 is harder than portion 126, and portion 126 has a greater structural fatigue strength than portion 124. Because spark plasma sintering contains powders 118 and 120 in the same housing 114, portions 124 and 126 are integral and form a single part without the need for an assembly process.

[0061] The method includes a step E05 of machining the preform 122. Step E05 involves machining operations to give the preform 122 the shape of an outer ring 6. More specifically, in step E05, the lower portion 124 is machined to have the shape of a contact portion 52, and the upper portion 126 is machined to have the shape of a cage 32.

[0062] The method includes step E06 of heat treatment of the preform 122. Step E06 involves performing at least one heat treatment selected from quenching, tempering, and annealing.

[0063] The result of this process is as follows Figure 1 The ring 6 shown is produced as follows. The resulting ring 6 has: a contact portion 52 made of a sufficiently hard material to form an effective raceway for the rolling elements; and a fastening portion that is lightweight and has suitable structural fatigue strength. The contact portion and the fastening portion are formed integrally, and no welding operation is required. This results in reduced manufacturing costs and improved reliability of the ring 6.

[0064] Conceiving the sintering of powders 118 and 120 by hot isostatic pressing rather than by spark plasma sintering does not depart from the scope of the invention. Hot isostatic pressing is also known as the abbreviation HIP.

[0065] Similarly, it is conceivable that at least one metal powder may be added in addition to powders 118 and 120. For example, the metal powder may be added vertically between powders 118 and 120. The metal powder inserted in this way can form the transition section between portions 124 and 126.

[0066] Furthermore, it is envisioned that exchanging steps E05 and E06 does not depart from the scope of the present invention. Similarly, some processing operations can be performed before the heat treatment operation, and other processing operations can be performed after the heat treatment operation, or even some heat treatment operations can be performed before the processing operation, and other heat treatment operations can be performed after the processing operation.

[0067] Using a cylinder 116 is advantageous because it reduces the number of machining operations that must be performed during step E05. It is also conceivable that, in the initial state of the method, the cylinder 116 is not arranged within the housing 114. In this case, the preform 122 obtained at the end of step E04 will not be hollow, as... Figure 4 As shown.

[0068] It is also conceivable to repeat the stages consisting of steps E01 and E02 multiple times. As a result, the housing 114 comprises multiple sections, each vertically inserted and each including the thickness of a first powder 118 and a second powder 120. In this case, at the end of step E04, the preform is a rod comprising sections inserted in this order: a section made of a first material, a section made of a second material, a section made of the first material, a section made of the second material, and so on. In this case, the method includes an additional step between steps E04 and E05, which includes, for example, sawing to cut a portion of the rod consisting of the sections made of the first material and the sections made of the second material to obtain a new preform identical to preform 122.

Claims

1. A ring (6) for connecting an element (2), comprising a contact portion (52) intended to mate with a contact surface (14) of another ring (4) and a fastening portion intended to be secured to a support, characterized in that, The contact portion (52) includes an outer surface (18), an inner surface (20) forming an outer raceway, and a sidewall (22) connecting the outer surface (18) and the inner surface (20), the fastening portion extending axially from the sidewall (22); The contact portion (52) is made of a first metal material, and the fastening portion is made of a second metal material. The contact portion (52) and the fastening portion are integrated by sintering metal powder. The hardness of the first metal material is strictly greater than that of the second metal material, and the toughness of the second metal material is strictly greater than that of the first metal material. The contact portion (52) and the fastening portion are integrated.

2. The ring (6) according to claim 1, wherein, The fastening portion includes a retainer (32), which includes a radial fastening edge (34) and a basic axial portion (38) provided with a plurality of circumferentially distributed windows (40).

3. A connecting element (2) intended to be incorporated into an aircraft, comprising a first ring (6) and a second ring (4), the first ring (6) and the second ring (4) being mounted to be rotatable relative to each other about an axis, the first ring (6) being the ring according to any one of claims 1 to 2.

4. The connecting element (2) according to claim 3, wherein, The contact portion (52) includes an inner surface (20), and the connecting element (2) includes at least one row of rolling elements (28) between the inner surface (20) of the first ring (6) and the contact surface (14) of the second ring (4).

5. A method for manufacturing a ring (6) for connecting element (2) according to any one of claims 1 to 2, comprising the following sequential steps: step E01: storing a first metal powder (118) in a housing (114); step E02: storing a second metal powder (120) in the housing (114), the second metal powder (120) being different from the first metal powder (118); and step E04: sintering the first metal powder (118) and the second metal powder (120) stored in the housing (114) to integrally form the contact portion (52) and the fastening portion of the ring (6).

6. The method according to claim 5 further includes storing a third metal powder in the housing (114), the third metal powder being different from the first metal powder (118) and the second metal powder (120), and sintering the first metal powder (118) and the second metal powder (120) stored in the housing (114) to integrally form an additional portion of the ring (6) with the contact portion (52) and the fastening portion.

7. The method according to claim 5 or 6, comprising placing a spacer device (116) in the housing (114) prior to step E01 of storing the first metal powder, wherein the first metal powder (118) and the second metal powder (120) stored in the housing (114) are arranged around the spacer device (116).

8. The method according to any one of claims 5 to 6, wherein, Step E04, which involves sintering the first metal powder (118) and the second metal powder (120), includes spark plasma sintering and / or hot isostatic pressing.

9. The method according to any one of claims 5 to 6, further comprising a heat treatment step E06 and / or a machining step E05 following step E04 of sintering the first metal powder (118) and the second metal powder (120).

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