Device for fixing a turbomachine pipe to a turbomachine support, associated assembly and method
The interlocking comb system with differential thermal expansion addresses the inefficiencies of traditional fixing collars by enabling tool-free, compact, and durable pipe fixation in turbomachines.
Patent Information
- Application Number
- FR2023012146
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-11-08
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2043-11-08
AI Technical Summary
The use of fixing collars for turbomachine pipes is time-consuming, requires specific tools, constrains design, increases wear due to hyperstaticity, and reduces service life, especially under vibratory conditions.
A fixing device with interlocking combs made of materials with different thermal expansion coefficients, allowing nesting and secure fastening through thermal expansion, eliminating the need for tools and reducing size constraints.
Facilitates quick and tool-free installation, reduces material consumption, extends service life, and enhances mechanical stability under thermal and vibratory conditions.
Smart Images
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Abstract
Description
Title of the invention: Device for fixing a turbomachine pipe to a turbomachine support, associated assembly and method Technical field
[0001] The present invention relates to the field of fixing pipes of an aircraft turbomachine.
[0002] As is known, a turbomachine comprises numerous pipes, also called conduits, for carrying fuel, oil or other fluid to different locations in the turbomachine. The pipes are fixed to a casing of the turbomachine by means of fixing collars secured to the casing of the turbomachine. In practice, a fixing collar comprises a peripheral belt and at least one clamping screw which must be tightened by an operator when fixing a pipe in order to reduce the length of the peripheral belt. During maintenance operations, the fixing collar must be loosened to release the pipe and then tightened again after maintenance.
[0003] The use of a fixing collar has many disadvantages. First of all, the tightening / loosening operations are very time-consuming. This is a disadvantage during maintenance operations on the under-wing turbomachine (without removing the propulsion unit) which must be carried out in a short time. It is also necessary to have specific tightening tools, for example a torque wrench to apply the appropriate tightening.
[0004] Furthermore, it is necessary to provide, from the design stage of the turbomachine, space for the passage of a tightening key and for its movement, which significantly constrains the design and increases the overall size. The use of fixing collars to fix a pipe leads to hyperstaticity, which increases wear and reduces the service life. This wear is amplified by thermal expansion and vibrations.
[0005] One of the objectives of the present invention is to improve the fixing of the pipes of a turbomachine in order to increase and optimize the manufacturing, production and / or repair capacity and, consequently, to significantly reduce the associated greenhouse gas emissions. This optimization also makes it possible to reduce the consumption of raw materials. It makes it possible to extend the service life of the components and, consequently, to reduce the number of replacements with new parts. PRESENTATION OF THE INVENTION
[0006] The invention relates to a device for fixing a turbomachine pipe to a turbomachine support, the fixing device comprising: • A first fixing member comprising a first base configured to be fixed to the turbomachine pipe and a first comb, the first comb comprising a plurality of first teeth, each first tooth extending parallel to a first axis, the plurality of first teeth being aligned along a second axis, orthogonal to the first axis, the first teeth being formed in a first material having a first coefficient of thermal expansion, • A second fixing member comprising a second base configured to be fixed to the turbomachine support and a second comb, the second comb comprising a plurality of second teeth, each second tooth extending parallel to the first axis, the plurality of second teeth being aligned along the second axis, the second teeth being formed in a second material having a second coefficient of thermal expansion, • The first coefficient of thermal expansion and the second coefficient of thermal expansion being chosen so that the first comb fits with the second comb according to a plurality of elementary clearances for a given maintenance temperature, the plurality of elementary clearances being filled by thermal expansion for a given operating temperature.
[0007] Thanks to the invention, elementary clearances are available to allow the first comb and the second comb to be nested effortlessly and without tools. It is therefore not necessary to provide space for handling tools. The turbomachine can advantageously be more compact. Advantageously, thermal expansion is used to ensure filling of the elementary clearances and efficient securing by nesting of the teeth. Friction forces ensure locking of the fixing. The nesting force can be adjusted by the sizing of the combs in order to allow sliding for optimal positioning. This is particularly advantageous for use in vibratory conditions.
[0008] Preferably, the maintenance temperature is less than or equal to 50°C. Preferably, the operating temperature is greater than or equal to 200°C.
[0009] According to one aspect, the first comb is configured to translate relative to the second comb along the first axis. This allows for continuous longitudinal adjustment.
[0010] According to one aspect, the first comb is configured to translate relative to the second comb along a third axis which is orthogonal to the first axis and to the second axis. This ensures continuous vertical adjustment.
[0011] According to one aspect, the first comb comprises between 4 and 20 first teeth. Such a number of teeth makes it possible to have a friction surface which is large while allowing lateral adjustment by offsetting the combs.
[0012] According to one aspect, a first tooth has a height of between 5 and 50 mm. Such a tooth height makes it possible to have a friction surface which is significant while allowing vertical adjustment.
[0013] In one aspect, the first base is formed from a material having a basic coefficient of thermal expansion and the first comb is formed from a material having a comb coefficient of thermal expansion that is greater than the basic coefficient of thermal expansion. This advantageously allows the first teeth to expand more than they shift relative to each other. The interlocking force can thus be adjusted with greater precision, thereby ensuring optimal fastening.
[0014] According to one aspect, an elementary game J' being defined at the operating temperature by the following relation: • J = p-E5+ (p*a40-E5*a41) *AT with • p: the spacing between a first tooth and a second tooth at maintenance temperature, • E5: a thickness of a second tooth, • a40: the basic coefficient of thermal expansion, • a41: the thermal expansion coefficient of the comb, • AT: the temperature difference between the operating temperature and the maintenance temperature.
[0015] Thus, by adjusting the coefficients of thermal expansion, the value of the clearances at the maintenance temperature and / or the value of the spacing pitch, the interlocking force is precisely determined to ensure fixing.
[0016] According to one aspect, the first teeth have different heights along the second axis. Preferably, the first teeth are higher at one end of the first comb than at its center.
[0017] This advantageously makes it possible to increase the friction surface without impacting the size when the fixing member is fixed to a turbomachine pipe whose outer surface is convex.
[0018] The invention also relates to an assembly comprising a turbomachine pipe, a turbomachine support and a fixing device as presented previously, the first fixing member being fixed to the turbomachine pipe, the second fixing member being fixed to the turbomachine support.
[0019] Also presented is a turbomachine comprising an assembly as presented previously and an aircraft comprising at least one such turbomachine.
[0020] The invention also relates to a method for fixing a turbomachine pipe to a turbomachine support with a fixing device as presented previously, the first fixing member being fixed to the turbomachine pipe, the second fixing member being fixed to the turbomachine support, the method comprising steps consisting of: • Nest the first comb with the second comb according to a plurality of elementary sets at a given maintenance temperature in which the turbomachine is switched off, and • Turn on the turbomachine so as to reach a given operating temperature in order to fill the plurality of elementary clearances by expansion. PRESENTATION OF FIGURES
[0021] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.
[0022] [Fig.l] is a schematic representation of a fixing device according to one embodiment.
[0023] [Fig.2] is a close-up schematic representation of the combs of the fixing device.
[0024] [Fig. 3] is a schematic cross-sectional representation of the thermal expansions of the combs for a first fixing member having a base and a first comb made of the same material.
[0025] [Fig.4] is a schematic sectional representation of a first fixing member having a base and a first comb made of different materials.
[0026] [Fig.5] is a labeled schematic representation of [Fig.4].
[0027] [Fig.6] is a close-up schematic representation of a variant of the combs of the fixing device.
[0028] [Fig.7] is a schematic representation seen from below of the attachment of the first attachment member.
[0029] [Fig.8] is a schematic representation of steps for attaching a turbomachine pipe to a turbomachine support.
[0030] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION
[0031] With reference to [Fig.l], there is shown the fixing of a turbomachine pipe 2 to a turbomachine support 1 by means of a fixing device 3 according to one embodiment of the invention. The turbomachine is preferably an aircraft turbomachine, in particular, for providing propulsion for said aircraft. The turbomachine pipe 2 can carry any type of fluid, in particular air, oil or fuel. In this example, the turbomachine support 1 is a turbomachine casing but it goes without saying that it could be in a different form.
[0032] As illustrated in [Fig.l], the fixing device 3 comprises a first fixing member 4 comprising a first base 40 fixed to the turbomachine pipe 2 and a first comb 4L. The first comb 41 is integral with the first base 40. In this first embodiment, the first fixing member 4 is in one piece. The first base 40 is in the form of a block which is mounted on a belt 20 of the turbomachine pipe 2 but it could be fixed in a different manner.
[0033] The fixing device 3 further comprises a second fixing member 5 comprising a second base 50 fixed to the turbomachine support 1 and a second comb 51. The second comb 51 is integral with the second base 50. Preferably, the second fixing member 5 is in one piece. The second base 50 is in this example in the form of a block mounted on the turbomachine support 1 but it could have a different shape.
[0034] The fixing of the bases 40, 50 can be carried out by any fixing means, gluing, screwing, etc. For the fixing of the first base 40, the fixing can be carried out by brazing, additive manufacturing or by means of a belt or other. According to one aspect, only the first comb 41 could be manufactured in an additive manner. For the fixing of the second base 50, the fixing can be carried out by brazing, additive manufacturing, screwing or other. In [Fig.7], a fixing nut 52 can for example be mounted between the second teeth 510 of the second comb 51 in order to secure the second base 50 to the turbomachine support 1. According to one aspect, only the second comb 51 could be manufactured in an additive manner.
[0035] In order to allow the first fixing member 4 to be secured to the second fixing member 5, the first comb 41 can fit into the second comb 51 as illustrated in [Fig.l].
[0036] The nesting of the combs 41, 51 is illustrated in Figures 2 and 3. The first comb 41 comprises a plurality of first teeth 410. Preferably, the number of first teeth 410 is between 4 and 20. Each first tooth 410 extends parallel to a first axis X. The first teeth 410 are aligned along a second axis Y. Each first tooth 410 extends vertically along a third axis Z. Similarly, the second comb 51 comprises a plurality of second teeth 510. Preferably, the number of second teeth 510 is between 4 and 20. Each second tooth 510 extends parallel to the first axis X. The second teeth 510 are aligned along the second axis Y. Each second tooth 510 extends vertically along the third axis Z. Preferably, the first comb 41 and the second comb 51 have the same number of teeth 410, 510 to + / - 1 tooth. This makes it possible to have an overlap which implements all the teeth 410, 510.
[0037] Thus, the first comb 41 can interlock with the second comb 51. Preferably, with reference to [Fig. 2], the teeth 410, 510 have lengths L4, L5, defined along the first axis X, which are substantially equal to + / - 10%. Preferably, the length L4, L5 of the teeth 410, 510 is between 5mm and 50mm. Such a length advantageously makes it possible to achieve a longitudinal offset dx ([Fig. 8]) but also to adjust the interlocking force as will be presented later.
[0038] With reference to [Fig. 3] showing a sectional view of the interlocking of the teeth 410, 510, at a given maintenance temperature, each first tooth 410 has a height H4 defined along the third axis Z and a thickness E4 defined along the second axis Y. The first teeth 410 are spaced apart by a first pitch P4 defined along the second axis Y. Similarly, each second tooth 510 has a height H5 defined along the third axis Z and a thickness E5 defined along the second axis Y. The second teeth 510 are spaced apart by a second pitch P5 defined along the second axis Y. Preferably, the first pitch P4 is identical to the second pitch P5. Preferably, the maintenance temperature is less than 50°C.
[0039] The dimensions of the teeth 410, 510 vary depending on the thermal expansion. Indeed, the first teeth 410 are formed in a first material having a first coefficient of thermal expansion while the second teeth 510 are formed in a second material having a second coefficient of thermal expansion.
[0040] The first coefficient of thermal expansion and the second coefficient of thermal expansion are chosen so that the first comb 41 fits with the second comb 51 according to a plurality of elementary clearances J for the maintenance temperature. For a given operating temperature, the plurality of elementary clearances is filled by thermal expansion. Preferably, the operating temperature is greater than 200°C.
[0041] The maintenance temperature is reached when the turbomachine is switched off, in particular, during maintenance, overhaul, etc. The operating temperature is reached when the turbomachine is switched on. The operating temperature depends in particular on the speed of the turbomachine.
[0042] Preferably, the first teeth 410 are formed from titanium having a first coefficient of thermal expansion equal to 9.10-6 / K while the second teeth 510 are formed from stainless steel having a second coefficient of thermal expansion equal to 1.5.10-6 / K. The second teeth 510 could be formed from ceramic which has a lower coefficient of thermal expansion compared to titanium.
[0043] At the maintenance temperature, the thickness E5 of a second tooth 510 is less than the first pitch P4 so that the second teeth 510 can be inserted between two first teeth 410 according to elementary clearances J. Similarly, the thickness E4 of a first tooth 410 is less than the second pitch P5 so that the first teeth 410 can be inserted between two second teeth 510 in order to allow nesting defining elementary clearances J, in particular along the second axis Y. The nesting can be carried out with reduced effort, without a specific tool. Preferably, the elementary clearances J are small and the first comb 41 is positioned in a stable manner with respect to the second comb 51 in order to allow sliding.
[0044] With reference to [Fig. 3], at the operating temperature, the thickness E4' of a first tooth 410 increases and becomes greater than the second pitch P5. The first teeth 410 expand between two second teeth 510 and are pressed against each other by an interlocking force linked to thermal expansion. The elementary clearances J disappear and the combs 41, 51 are secured in the stable interlocking position determined at the maintenance temperature. In other words, the expansion of the first teeth 410 and the expansion of the second teeth 510 combined fills the elementary clearance J. The sum of the two thicknesses when hot is greater than twice the pitch P4 / P5.
[0045] The interlocking force can be adapted by modifying the dimensions of the teeth 410, 510 but also the choice of the materials constituting them.
[0046] According to a variant illustrated in Figures 4 and 5, the first fixing member 4 comprises a base 40 formed in a material having a basic thermal expansion coefficient a40 and a comb 41 formed in a material having a comb thermal expansion coefficient a41 which is greater than the basic thermal expansion coefficient a40. In other words, the first teeth 410 expand more than they spread apart.
[0047] With reference to [Fig.5], the elementary clearance J at the maintenance temperature is defined as the gap between two teeth 410, 510.
[0048] J = y2-yï
[0049] 1 4-
[0050] =
[0051] p is the spacing pitch between the teeth 410, 510 at the maintenance temperature and depends on the thermal expansion of the first base 40.
[0052] Similarly, we define an elementary game J' at the operating temperature as the gap between two teeth 410, 510 after expansion.
[0053]
[0054] Thermal expansion is defined according to the following relationships
[0055] 5^ =
[0056] AT being the temperature difference between the operating temperature and the maintenance temperature.
[0057] ôy2 = p*a40*JT - f
[0058] = +
[0059] y2 = p(l + a40*dT) -f (l + a4iW)
[0060] / = p(1 + a40W) -Ç (1 + a4!*^) - W + «4i
[0061] J = p-E5+ (p*a40-£5*a41) *AT
[0062] Thus, if we want a cancellation of the elementary clearance J' at the operating temperature (J'=0), that is to say an interlocking, we advantageously have a mathematical relationship to choose the thermal expansion coefficients. In practice, the elementary clearance J' at the operating temperature is less than 0 from an analytical point of view so as to achieve tightening.
[0063] For example, the base 40 is formed from titanium or ceramic while the comb 41 is formed from stainless steel (Inconel, Hastelloy X, etc.).
[0064] According to a variant, with reference to [Fig. 6], the first teeth 410 and / or the second teeth 510 have different heights in order to match the curvature of the turbomachine pipe 2 while increasing the contact surface with the other comb. Preferably, the teeth 410, 510 are higher at one end of the comb 41, 51 than at its center. This makes it possible to increase the length of the teeth 410, 510 and therefore the interlocking force while having a reduced size when fixing a turbomachine pipe 2 which is convex.
[0065] According to a preferred aspect, the first teeth 410 extend orthogonally to the base 40 but it goes without saying that they could extend obliquely relative to this orthogonal direction. This advantageously allows relative movement in the oblique direction during thermomechanical loading of the turbomachine pipe 2.
[0066] With reference to [Fig. 8], a method of fixing a turbomachine pipe 2 to a turbomachine support 1 is shown schematically. As illustrated in step 8a, the first fixing member 4 has been previously fixed to the turbomachine pipe 2 while the second fixing member 5 has been previously fixed to the turbomachine support 1.
[0067] The method comprises a step 8b consisting of nesting the first comb 41 with the second comb 51 so as to cause the first fixing member 4 to cooperate in a stable manner with the second fixing member 5. This stable cooperation can advantageously be adjusted.
[0068] The method may advantageously comprise a step 8c of longitudinal adjustment dx along the first axis X in which the combs 41, 51 are offset so that teeth 410, 510 cooperate over a single portion of their length L4, L5. The longitudinal adjustment dx is carried out continuously, which is very advantageous.
[0069] The method may advantageously comprise a step 8d of lateral adjustment dy along the second axis Y in which the combs 41, 51 are offset so that teeth 410, 510 do not cooperate with each other. The lateral adjustment dy is carried out with a pitch which corresponds to the first pitch P4 or to the second P5 of the combs 41, 51. Preferably, the first pitch P4 is identical to the second pitch P5.
[0070] The method may advantageously comprise a step 8e of vertical adjustment dz along the third axis Z in which the combs 41, 51 are offset vertically so that teeth 410, 510 cooperate over a single portion of their height H4, H5. The vertical adjustment dz is carried out continuously, which is very advantageous.
[0071] The different settings presented above can be combined with each other to advantageously allow a global setting.
[0072] Thanks to the invention, a turbomachine pipe 2 can be fixed without tools or serial screws, which reduces the fixing time as well as the space requirement. This is particularly advantageous during maintenance operations carried out under the wing.
[0073] When the turbomachine is switched on, its temperature increases until it reaches the operating temperature so as to fill the plurality of elementary clearances J by thermal expansion.
[0074] During operation of the turbomachine, the teeth 410, 510 of the combs 41, 51 are in contact, which makes it possible to lock the connection thanks to friction. If the interlocking force is greater than a sliding limit, the fixing will be completely locked.
[0075] A reduced interlocking force may be advantageous to allow limited locking. The friction between the teeth 410, 510 allows strong damping until the energy of the movement is absorbed, which is advantageous for the mechanical strength of the turbomachine pipe 2, in particular, in vibration conditions.
Claims
Claims
1. A device (3) for fixing a turbomachine pipe (2) to a turbomachine support (1), the fixing device (3) comprising: • A first fixing member (4) comprising a first base (40) configured to be fixed to the turbomachine pipe (2) and a first comb (41), the first comb (41) comprising a plurality of first teeth (410), each first tooth (410) extending parallel to a first axis (X), the plurality of first teeth (410) being aligned along a second axis (Y), orthogonal to the first axis (X), the first teeth (410) being formed from a first material having a first coefficient of thermal expansion, • A second fixing member (5) comprising a second base (50) configured to be fixed to the turbomachine support (1) and a second comb (51), the second comb (51) comprising a plurality of second teeth (510),each second tooth (510) extending parallel to the first axis (X), the plurality of second teeth (510) being aligned along the second axis (Y), the second teeth (510) being formed in a second material having a second coefficient of thermal expansion, • The first coefficient of thermal expansion and the second coefficient of thermal expansion being chosen so that the first comb (41) fits with the second comb (51) according to a plurality of elementary clearances (J) for a given maintenance temperature, the plurality of elementary clearances (J) being filled by thermal expansion for a given operating temperature.,
2. A fixing device according to claim 1, wherein the first comb (41) is configured to translate relative to the second comb (51) along the first axis (X).
3. Fixing device according to one of claims 1 to 2, in which the first comb (41) is configured to translate relative to the second comb (51) along a third axis (z) which is orthogonal to the first axis (X) and to the second axis (Y).
4. Fastening device according to one of claims 1 to 3, in which the first comb (41) comprises between 4 and 20 first teeth (410).
5. A fixing device according to one of claims 1 to 4, wherein the first base (40) is formed from a material having a base thermal expansion coefficient (a40) and the first comb (41) is formed from a material having a comb thermal expansion coefficient (a41) which is greater than the base thermal expansion coefficient (a40).
6. Fastening device according to claim 5, in which an elementary clearance J' being defined at the operating temperature by the following relation: • J = p - E5 + ( p*«4o " E5*«41 ) *AT with • p: the spacing pitch between a first tooth (410) and a second tooth (510) at the maintenance temperature, • E5: a thickness of a second tooth (510), • a40: the basic thermal expansion coefficient, • a41: the comb thermal expansion coefficient, • AT: the temperature difference between the operating temperature and the maintenance temperature.
7. Fastening device according to one of claims 1 to 6, in which the first teeth (410) have different heights along the second axis (Y).
8. A fastening device according to claim 7, wherein the first teeth (410) are higher at one end of the first comb (41) than at its center.
9. Assembly comprising a turbomachine pipe (2), a turbomachine support (1) and a fixing device (3) according to one of claims 1 to 8, the first fixing member (4) being fixed to the turbomachine pipe (2), the second fixing member (5) being fixed to the turbomachine support (1).
10. Method for fixing a turbomachine pipe (2) to a turbomachine support (1) with a fixing device (3) according to one of claims 1 to 8, the first fixing member (4) being fixed to the turbomachine pipe (2), the second fixing member (5) being fixed to the turbomachine support (1), the method comprising steps consisting of: Nesting the first comb (41) with the second comb (51) according to a plurality of elementary sets (J) at a given maintenance temperature in which the turbomachine is switched off, and Ignite the turbomachine so as to reach a given operating temperature so as to fill the plurality of elementary clearances (J) by expansion.