Device for attaching a turbomachine pipe to a turbomachine support, assembly and associated method

Abstract

A fastening device (3) for a turbomachine duct (2) to a turbomachine support (1), the fastening device (3) comprising a first fastening member (4) including a first base (40) and a first comb (41), the first comb (41) including a plurality of first teeth (410) having a first coefficient of thermal expansion, a second fastening member (5) including a second base (50) and a second comb (51) including second teeth (510) having a second coefficient of thermal expansion, the coefficients of thermal expansion being chosen such that the first comb (41) interlocks with the second comb (51) 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. Abstract figure: Figure 1

Description

Title of the invention: Device for attaching a turbomachine pipe to a turbomachine support, assembly and associated method technical field

[0001] The present invention relates to the field of pipe fixing of a turbomachine for aircraft.

[0002] As is known, a turbomachine has numerous lines, also called pipes, for conveying fuel, oil, or other fluids to various locations within the turbomachine. The lines are attached to the turbomachine housing by means of retaining clamps that are integral with the housing. In practice, a retaining clamp has a peripheral band and at least one clamping screw that must be tightened by an operator when attaching a line in order to reduce the length of the peripheral band. During maintenance operations, the retaining clamp must be loosened to free the line and then tightened again after maintenance.

[0003] The use of a retaining collar presents several disadvantages. First, tightening and loosening the collar is very time-consuming. This is a significant drawback during maintenance operations on the underwing turbomachine (without removing the propulsion assembly), which must be carried out within a limited timeframe. Furthermore, specific tightening tools are required, such as a torque wrench, to apply the correct torque.

[0004] Furthermore, it is necessary to provide space for the passage and movement of a tightening wrench during the turbomachine design phase, which significantly constrains the design and increases the overall size. The use of clamps to secure a pipe induces excessive static loads, which increase wear and reduce service life. This wear is amplified by thermal expansion and vibrations.

[0005] One of the objectives of the present invention is to improve the fastening of the pipes of a turbomachine in order to increase and optimize manufacturing, production, and / or repair capacity and, consequently, to significantly reduce associated greenhouse gas emissions. This optimization also reduces raw material consumption. It extends the service life of the components and, therefore, reduces the number of replacements with new parts. PRESENTATION OF THE INVENTION

[0006] The invention relates to a device for attaching a turbomachine pipe to a turbomachine support, the attachment device comprising: • A first fastening member comprising a first base configured to be fixed to the turbomachine duct 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 fastening 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 interlocks with the second comb according to a plurality of elementary gaps for a given maintenance temperature, the plurality of elementary gaps being filled by thermal expansion for a given use temperature.

[0007] Thanks to the invention, elementary gaps are provided to allow the first and second combs to be interlocked effortlessly and without tools. It is therefore unnecessary to provide space for tool handling. The turbomachine can advantageously be more compact. Advantageously, thermal expansion is used to ensure that the elementary gaps are filled and that the teeth are securely interlocked. Friction forces ensure the locking of the attachment. The interlocking force can be adjusted by sizing the combs 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 ensures 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 allows for continuous vertical adjustment.

[0011] According to one aspect, the first comb comprises between 4 and 20 teeth. Such a number of teeth provides a large friction surface 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 provides a large friction surface while allowing for vertical adjustment.

[0013] According to 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, ensuring optimal fastening.

[0014] According to one aspect, an elementary set J' is defined at the operating temperature by the following relation: • J = p-E5+ (p*a40-E5*a41) *AT with • p: the pitch between the first and second teeth at the maintenance temperature, • E5: a thickness of one second tooth, • a40: the basic coefficient of thermal expansion, • a41: the coefficient of thermal expansion 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 gaps at the maintenance temperature and / or the value of the spacing pitch, the interlocking force to ensure fixation is precisely determined.

[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 allows the friction surface to be increased without impacting the overall size when the fastening member is fixed to a turbomachine duct whose outer surface is convex.

[0018] The invention also relates to an assembly comprising a turbomachine duct, a turbomachine support and a fastening device as previously presented, the first fastening member being fixed to the turbomachine duct, the second fastening member being fixed to the turbomachine support.

[0019] A turbomachine comprising an assembly as shown is also presented. previously and an aircraft comprising at least one such turbomachine.

[0020] The invention also relates to a method for attaching a turbomachine pipe to a turbomachine support with a fastening device as described above, the first fastening member being attached to the turbomachine pipe, the second fastening member being attached to the turbomachine support, the method comprising steps consisting of: • Interlock the first comb with the second comb according to a plurality of elementary sets at a given maintenance temperature in which the turbomachine is shut down, and • Turn on the turbomachine so as to reach a given operating temperature in order to fill the plurality of elementary gaps by expansion. PRESENTATION OF THE FIGURES

[0021] The invention will be better understood upon reading the following description, 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. 1 is a schematic representation of a fastening device according to one embodiment.

[0023] Fig. 2 is a close schematic representation of the combs of the fastening 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 cross-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] Figure 6 is a close-up schematic representation of a variant of the combs of the fastening device.

[0028] Fig. 7 is a schematic representation viewed from below of the attachment of the first attachment member.

[0029] Fig. 8 is a schematic representation of steps for fixing 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 being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0031] With reference to [Fig. 1], the attachment of a turbomachinery pipe is shown. 2 to a turbomachine support 1 by means of a fastening device 3 according to an embodiment of the invention. The turbomachine is preferably an aircraft turbomachine, in particular, to provide propulsion for said aircraft. The turbomachine duct 2 can carry any type of fluid, in particular, air, oil, or fuel. In this example, the turbomachine support 1 is a turbomachine housing, but it is understood that it could be in a different form.

[0032] As illustrated in [Fig. 1], the fastening device 3 comprises a first fastening member 4 including a first base 40 fixed to the turbomachine duct 2 and a first comb 41. The first comb 41 is integral with the first base 40. In this first embodiment, the first fastening member 4 is a single piece. The first base 40 is in the form of a block that is mounted to a belt 20 of the turbomachine duct 2, but it could be fixed in a different manner.

[0033] The fastening device 3 further comprises a second fastening member 5 including 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 fastening member 5 is a single piece. In this example, the second base 50 is in the form of a block mounted to the turbomachine support 1, but it could have a different shape.

[0034] The bases 40, 50 can be attached by any means, such as gluing, screwing, etc. For the first base 40, attachment can be achieved by brazing, additive manufacturing, or by means of a belt or other method. In one aspect, only the first comb 41 could be additively manufactured. For the second base 50, attachment can be achieved by brazing, additive manufacturing, screwing, or other methods. In [Fig. 7], a retaining nut 52 can, for example, be mounted between the second teeth 510 of the second comb 51 to secure the second base 50 to the turbomachine support 1. In one aspect, only the second comb 51 could be additively manufactured.

[0035] In order to allow the first fixing member 4 to be joined with the second fixing member 5, the first comb 41 can be fitted together with the second comb 51 as illustrated in [Fig.1].

[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 X-axis. The second teeth 510 are aligned along the second Y-axis. Each second tooth 510 extends vertically along the third Z-axis. Preferably, the first comb 41 and the second comb 51 have the same number of teeth 410, 510, within + / - 1 tooth. This allows for an overlap that utilizes 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 X-axis, which are approximately equal to + / - 10%. Preferably, the length L4, L5 of the teeth 410, 510 is between 5 mm and 50 mm. Such a length advantageously allows for a longitudinal offset dx ([Fig. 8]) and also for adjusting the interlocking force, as will be shown later.

[0038] With reference to [Fig. 3], which shows a cross-sectional view of the interlocking of teeth 410 and 510 at a given maintenance temperature, each first tooth 410 has a height H4 defined along the third Z-axis and a thickness E4 defined along the second Y-axis. The first teeth 410 are spaced apart by a first pitch P4 defined along the second Y-axis. Similarly, each second tooth 510 has a height H5 defined along the third Z-axis and a thickness E5 defined along the second Y-axis. The second teeth 510 are spaced apart by a second pitch P5 defined along the second Y-axis. Preferably, the first pitch P4 is identical to the second pitch P5. Preferably, the maintenance temperature is below 50°C.

[0039] The dimensions of the teeth 410, 510 vary according to 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 and second coefficients of thermal expansion are chosen such that the first comb 41 interlocks with the second comb 51 according to a plurality of elementary gaps J at the maintenance temperature. For a given operating temperature, the plurality of elementary gaps is filled by thermal expansion. Preferably, the operating temperature is above 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 turbomachine's speed.

[0042] Preferably, the first teeth 410 are formed from titanium having a first coefficient of thermal expansion of 9 x 10⁻⁶ K, while the second teeth 510 are formed from stainless steel having a second coefficient of thermal expansion of 1.5 x 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 fit 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 fit between two second teeth 510 to allow interlocking that defines elementary clearances J, in particular along the second axis Y. The interlocking can be achieved with reduced force, without a specific tool. Preferably, the elementary clearances J are small and the first comb 41 is stably positioned relative to the second comb 51 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 related to thermal expansion. The elementary gaps J disappear, and the combs 41, 51 are joined in the stable interlocking position determined at the maintenance temperature. In other words, the combined expansion of the first teeth 410 and the expansion of the second teeth 510 closes the elementary gap 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 pitch between the teeth 410, 510 at the maintenance temperature and depends on the thermal expansion of the first base 40.

[0052] Similarly, an elementary clearance J' at the operating temperature is defined as the gap between two teeth 410, 510 after dilation.

[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 the elementary clearance J' at the operating temperature is to be eliminated (J'=0), i.e., if interlocking is desired, a mathematical relationship is advantageously available for choosing the coefficients of thermal expansion. In practice, the elementary clearance J' at the operating temperature is less than 0 from an analytical point of view in order to achieve tightening.

[0063] By way of example, the base 40 is formed of titanium or ceramic while the comb 41 is formed of stainless steel (Inconel, Hastelloy X, ...).

[0064] According to one embodiment, with reference to [Fig. 6], the first teeth 410 and / or the second teeth 510 have different heights in order to conform to the curvature of the turbomachine 2 duct while increasing the contact area with the other comb. Preferably, the teeth 410, 510 are taller at one end of the comb 41, 51 than at its center. This allows for an increase in the length of the teeth 410, 510 and therefore the interlocking force, while maintaining a reduced overall size when attaching a convex turbomachine 2 duct.

[0065] According to a preferred aspect, the first teeth 410 extend orthogonally to the base 40, but it is understood that they could extend obliquely with respect to this orthogonal direction. This advantageously allows for relative displacement along the oblique direction during the thermomechanical loading of the turbomachine duct 2.

[0066] With reference to [Fig.8], a method for fixing a turbomachine pipe 2 to a turbomachine support 1 is schematically represented. 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 process includes a step 8b consisting of nesting the first comb 41 with the second comb 51 so as to make the first fixing member 4 cooperate stably with the second fixing member 5. This stable cooperation can be advantageously adjusted.

[0068] The method may advantageously include a longitudinal adjustment step 8c 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 include a lateral adjustment step 8d along the second Y-axis in which the combs 41, 51 are offset so that teeth 410, 510 do not cooperate with each other. The lateral adjustment dy is performed with a pitch that corresponds to the first pitch P4 or the second pitch P5 of the combs 41, 51. Preferably, the first pitch P4 is identical to the second pitch P5.

[0070] The method may advantageously include a vertical adjustment step 8e along the third axis Z in which the combs 41, 51 are vertically offset 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 various settings presented above can be combined with each other to advantageously allow for global adjustment.

[0072] Thanks to the invention, a turbomachine duct 2 can be fixed without tools or serial screws, which reduces both the fixing time and the overall size. 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 by thermal expansion the plurality of elementary gaps J.

[0074] During the operation of the turbomachine, the teeth 410, 510 of the combs 41, 51 are in contact, which allows the connection to be locked by friction. If the interlocking force exceeds a sliding limit, the fastening will be completely locked.

[0075] Reduced interlocking force can be advantageous to allow limited locking. Friction between the teeth 410, 510 provides strong damping until the displacement energy is absorbed, which is advantageous for the mechanical strength of the turbomachine duct 2, particularly under vibratory 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.

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