Coupling for connecting ends of two rotating shafts

Abstract

A coupling for connecting the ends (2A, 3A) of two rotating shafts (2, 3) comprises at least one surface at least partially covered with a friction coating (6) and intended to be at least partially in contact with at least one of the ends (2A, 3A) of the two shafts (2, 3) to be connected, said friction coating (6) comprising rough portions and pores projecting from said at least one surface. Furthermore, all or part of the friction coating (6) comprises a sealant (7) which fills the pores formed between the rough portions of the friction coating (6).

Description

Technical Field

[0001] The present invention relates generally to shaft connections, particularly in propulsion systems and drive shafts, and more particularly to sealing of shaft connections.

[0002] In particular, the present invention relates to a coupling for connecting the ends of two rotating shafts, a propulsion system comprising such a coupling and a method of manufacturing such a coupling. Background Art

[0003] Propulsion systems typically include multiple shafts, some of which require rotational couplings.

[0004] Couplings are used to connect the ends of two adjacent shafts and transfer torque from one shaft to another.

[0005] In particular, a certain group of couplings includes a friction coating that contacts the ends of the two shafts to be connected. This friction coating greatly increases friction and provides higher torque capacity.

[0006] When a propulsion system comprises a hollow shaft and a device containing oil or other fluids, a sealing function is required to prevent leakage between the shaft and the rest of the propulsion system.

[0007] A well-known solution is to attach sealing rings to the coupling ends.

[0008] However, this solution requires additional components outside the coupling, which also increases the complexity of the propulsion system.

[0009] The present invention therefore aims to overcome these drawbacks by providing a simple and lightweight sealing solution between the ends of two shafts to be connected in rotation and a friction-coated coupling which does not require the installation of additional components. Summary of the invention

[0010] An object of the present invention is to provide a coupling for connecting the ends of two shafts, the coupling comprising at least one surface, which is at least partially covered with a friction coating and is used to at least partially contact at least one of the ends of the two shafts to be connected, the friction coating comprising roughness and pores protruding from the at least one surface.

[0011] Furthermore, all or part of the friction coating includes a sealant that fills pores formed between the roughnesses of the friction coating.

[0012] The sealant prevents oil or other fluids from leaking between the shaft and the coupling and vice versa, and prevents leakage from the propulsion system. The coupling now includes the sealing function and does not require external or additional components such as sealing rings.

[0013] Preferably, the size of the pores is between 0 and 0.2 mm.

[0014] Preferably, the size of the roughness is between 0 and 0.1 mm.

[0015] In the present description, the limits of a value range are included in the range, especially in the expression "between . . . and . . ."

[0016] More preferably, the sealant fills the pores of the friction coating at heights ranging from the lowest to the highest asperities.

[0017] In a first embodiment, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting ends of two shafts to be connected, and the friction coating at least partially covers the inner surface of the inner sleeve.

[0018] According to a general feature, the sealant is located on two spaced-apart regions, each region being located at one end of the inner sleeve, the sealant covering each region in a circumferential direction.

[0019] In a second embodiment, the coupling may include an inner sleeve and an outer sleeve installed around the inner sleeve, the inner sleeve having an inner surface for axially contacting one of the ends of the two shafts to be connected, the inner sleeve including a flange having a radial surface for radially contacting the flange of the other of the ends of the two shafts to be connected, and the friction coating at least partially covers the inner surface of the inner sleeve and the radial surface of the inner sleeve.

[0020] Alternatively, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting one of the ends of the two shafts to be connected, the inner sleeve including a flange having a radial surface for radially contacting a flange of the other of the ends of the two shafts to be connected, the friction coating at least partially covering the inner surface of the inner sleeve.

[0021] As another alternative, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting one of the ends of the two shafts to be connected, the inner sleeve including a flange having a radial surface for radially contacting a flange of the other of the ends of the two shafts to be connected, the friction coating at least partially covering the radial surface of the inner sleeve.

[0022] Alternatively, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting one end of two shafts to be connected, the outer sleeve including a flange having a radial surface for radially contacting a flange of the other of the ends of the two shafts to be connected, the friction coating at least partially covering the inner surface of the inner sleeve and the radial surface of the outer sleeve.

[0023] As another alternative, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting one of the ends of the two shafts to be connected, the outer sleeve including a flange having a radial surface for radially contacting a flange of the other of the ends of the two shafts to be connected, the friction coating at least partially covering the radial surface of the outer sleeve.

[0024] As another alternative, the coupling may include an inner sleeve and an outer sleeve mounted around the inner sleeve, the inner sleeve having an inner surface for axially contacting one of the ends of the two shafts to be connected, the outer sleeve including a flange having a radial surface for radially contacting a flange of the other of the ends of the two shafts to be connected, the friction coating at least partially covering the inner surface of the inner sleeve.

[0025] Preferably, the sealant comprises at least one polymer.

[0026] Advantageously, the sealant can be applied as a liquid polymer to the friction coating.

[0027] Another object of the present invention is to provide a propulsion system comprising two rotating shafts and at least one coupling as described above, the friction coating being in frictional engagement with at least one of the ends of the two rotating shafts.

[0028] Another object of the present invention is to provide a method for manufacturing a coupling as described above, which method comprises applying a sealant to all or part of the friction coating on the at least one surface of the coupling intended for contact with the ends of two shafts.

[0029] Advantageously, the sealant may be applied by brushing, spraying or dipping.

[0030] Advantageously, the method for manufacturing a shaft coupling may comprise a preliminary step of applying said friction coating on said at least one surface of the shaft coupling by thermal spraying.

[0031] Advantageously, the method for manufacturing a shaft coupling may comprise the step of smoothing said at least one surface of the shaft coupling intended for contact with the ends of the two shafts after applying the sealant. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other advantages and features of the invention will emerge from the detailed description of embodiments of the invention, which are non-limiting examples and are illustrated in the accompanying drawings:

[0033] - Figure 1 is a cross-sectional view through the longitudinal axis of a coupling connecting the ends of two shafts of a propulsion system according to a first embodiment of the present invention;

[0034] - Figure 2 It passes through Figure 1 A detailed view of the friction coating of the coupling is shown; and

[0035] - Figure 3 is a cross-sectional view through the longitudinal axis of a coupling connecting the ends of two shafts of a propulsion system according to a second embodiment of the invention. DETAILED DESCRIPTION

[0036] Figure 1 Shown are end portions 2A, 3A of first and second rotating shafts 2, 3 of a propulsion system according to a first embodiment of the present invention, and a coupling 1 mounted on the two shafts 2, 3 to be connected to each other.

[0037] The first and second shafts 2 , 3 shown are both hollow cylindrical shafts and extend along a common axis X.

[0038] The first and second shafts 2 and 3 include outer surfaces 2a and 3a, respectively.

[0039] The coupling 1 includes an inner sleeve 4 and an outer sleeve 5 installed around the inner sleeve 4 .

[0040] The inner sleeve 4 includes an inner surface 4 a that is in axial contact with the outer surfaces 2 a , 3 a of the first and second shafts 2 , 3 .

[0041] In addition, if Figure 2 As shown in the detailed view in , the inner surface 4a of the inner sleeve 4 is covered with a friction coating 6, which contacts the ends 2A, 3A of the first and second shafts 2, 3 to be connected. All the inner surface 4a of the inner sleeve 4 can be covered with the friction coating 6. Alternatively, only a portion of the inner surface 4a of the inner sleeve 4 can be covered with the friction coating 6.

[0042] The friction coating 6 includes pores and asperities protruding from the inner surface 4a of the inner sleeve 4. The pores extend inwardly from the inner surface 4a.

[0043] Furthermore, the friction coating 6 comprises a sealant 7 .

[0044] The sealant 7 advantageously fills the pores formed between the roughnesses of the friction coating 6. The sealant 7 is located on the inner surface 4a of the inner sleeve 4, and therefore between the coupling 1 and the ends 2A, 3A of the first and second shafts 2,3.

[0045] The sealant prevents oil or other fluids from leaking between the shafts 2, 3 and the coupling 1 and from leaking out of the propulsion system. The coupling 1 now also includes a sealing function.

[0046] The sealing function is included in the coupling 1 and no external or additional components, such as sealing rings, are required.

[0047] Preferably, the sealant 7 fills the pores of the friction coating 6 at heights ranging from the lowest to the highest asperities to provide a sealing function while continuing to perform its friction function.

[0048] The sealant 7 may include at least one polymer.

[0049] In the illustrated example, the sealant 7 covers the entire inner surface 4 a of the inner sleeve 4 .

[0050] Alternatively, the sealant 7 may only partially cover the inner surface 4 a of the inner sleeve 4 .

[0051] For example, the sealant 7 may be located on two spaced-apart regions, each region being located at one end of the inner sleeve 4, with the sealant 7 covering each region in the circumferential direction.

[0052] In the example shown in the figures, the coupling 1 comprises an inner sleeve 4 and an outer sleeve 5 .

[0053] Alternatively, the coupling 1 may comprise a single sleeve mounted around at least one of the first and second shafts 2 , 3 and comprising the friction coating 6 and the sealant 7 .

[0054] Figure 3 There is shown end portions 2A, 3A of first and second rotating shafts 2, 3 connected by a coupling 8 according to a second embodiment of the invention.

[0055] Figure 3 The examples shown (in which like parts are given like reference numerals) are similar to Figure 1 The first embodiment differs from the first embodiment in that the end 2A of the first shaft 2 comprises a flange 9 comprising a radial surface 2b.

[0056] The first shaft 2 may be part of a gearbox or a motor shaft, for example.

[0057] The coupling 8 includes an inner sleeve 10 and an outer sleeve 11 installed around the inner sleeve 10 .

[0058] The inner sleeve 10 includes an inner surface 10 a that is in axial contact with the end portion 3 a of the second shaft 3 .

[0059] At one of its ends, the inner sleeve 10 also comprises a flange 12 comprising a radial surface 10 b in contact with the radial surface 2 b of the first shaft 2 .

[0060] Furthermore, the inner surface 10a and the radial surface 10b of the inner sleeve 10 are covered with a friction coating 6, as described above, and Figure 2 The friction coating 6 is in contact with the radial surface 2b of the first shaft 2 and the outer surface 3a of the second shaft 3.

[0061] Furthermore, the friction coating 6 comprises a sealant 7 filling its pores as previously described, the sealant 7 being located between the coupling 8 and the ends 2A, 3A of the first and second shafts 2, 3.

[0062] The sealant 7 is located on the inner surface 10 a and the radial surface 10 b of the inner sleeve 10 , and therefore between the coupling 8 and the ends 2A, 3A of the first and second shafts 2 , 3 .

[0063] The sealant prevents oil or other fluids from leaking between the shafts 2, 3 and the coupling 8 and from leaking out of the propulsion system.

[0064] In the example shown, the coupling 8 comprises an inner sleeve 10 and an outer sleeve 11 .

[0065] Alternatively, the coupling 8 may comprise a single sleeve mounted around at least one of the first and second shafts 2 , 3 and comprising the friction coating 6 and the sealant 7 .

[0066] The invention also relates to a method for manufacturing a coupling 1 , 8 as described above, comprising applying a sealant to the friction coating 6 .

[0067] The sealant 7 may be applied by brushing, spraying or dipping.

[0068] Preferably, after applying the sealant 7 onto the friction coating 6 , the sealant 7 is smoothed such that the sealant 7 fills the pores of the friction coating 6 at heights ranging from the lowest to the highest asperities.

[0069] Advantageously, the method for manufacturing a shaft coupling may comprise a preliminary step of applying the friction coating 6 by thermal spraying.

[0070] Preferably, the friction coating 6 is formed by plasma technology and may include a carbide compound.

Claims

1. A coupling for connecting the ends (2A, 3A) of two shafts (2, 3), the coupling comprising at least one surface, the at least one surface being at least partially covered with a friction coating (6) and being intended to at least partially come into contact with at least one of the ends (2A, 3A) of the two shafts (2, 3) to be connected, the friction coating (6) comprising roughness and pores protruding from the at least one surface, wherein: The whole or part of the friction coating (6) includes a sealant (7) which fills the pores formed between the roughness parts of the friction coating (6).

2. The coupling according to claim 1, wherein: The sealant (7) fills the pores of the friction coating (6) at heights ranging from the lowest to the highest asperities.

3. A coupling according to any one of the preceding claims, comprising an inner sleeve (4) having an inner surface (4a) and an outer sleeve (5) mounted around the inner sleeve (4), wherein the inner surface (4a) is used to axially contact the ends (2A, 3A) of the two shafts (2, 3) to be connected, and the friction coating (6) at least partially covers the inner surface (4a) of the inner sleeve (4).

4. The coupling according to claim 3, wherein: The sealant (7) is located on two spaced-apart areas, each area being located at one end of the inner sleeve (4), and the sealant covers each area in the circumferential direction.

5. The coupling according to claim 1 or 2 comprises an inner sleeve (10) having an inner surface (10a) and an outer sleeve (11) installed around the inner sleeve (10), the inner surface (10a) being used for axially contacting one of the ends (2A, 3A) of the two shafts (2, 3) to be connected, the inner sleeve (10) or the outer sleeve (11) comprising a flange (12) having a radial surface (10b), the radial surface (10b) being used for radially contacting the flange (9) of the other of the ends of the two shafts (2, 3) to be connected, and the friction coating (6) at least partially covers the inner surface (10a) of the inner sleeve (10) and / or the radial surface (10b) of the outer sleeve (11) or the inner sleeve (10).

6. A propulsion system comprising two rotating shafts and at least one coupling (1; 8) according to any one of the preceding claims, the friction coating (6) being in frictional engagement with at least one of the ends (2A, 3A) of the two rotating shafts (2, 3).

7. A method for manufacturing a coupling according to any one of claims 1 to 5, comprising applying a sealant (7) to all or part of the friction coating (6) on at least one surface of the coupling intended for contact with the ends (2A, 3A) of two shafts (2, 3).

8. The method according to claim 7, wherein: The sealant (7) is applied by brushing, spraying or dipping.

9. Method according to claim 7 or 8, comprising the preliminary step of applying said friction coating (6) on said at least one surface of the coupling (1; 8) by thermal spraying.

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