Device and method for monitoring a disc brake system of an aircraft landing gear

Abstract

The present invention discloses an assembly including a disc braking system (2) and a monitoring device (3) for an aircraft landing gear (1). The disc braking system (2) includes at least one stator disc (21) and at least one rotor disc (22) configured to press against the stator disc (21). The monitoring device (3) includes: a measuring tape (30) including at least one visual information item related to a set circumference of the stator disc (21), the measuring tape (30) being configured to contact the outer circumference of the stator disc (21); a first gripper (31) connected to a first end of the measuring tape (30) and a second gripper (32) connected to a second end of the measuring tape (30) such that the measuring tape (30) can be stretched around the outer circumference of the stator disc (21) to accurately determine the circumference of the stator disc (21).

Description

Technical Field

[0001] This invention relates to the field of monitoring aircraft takeoff and landing devices, and more particularly to disc braking systems for takeoff and landing devices. Background Technology

[0002] Knownly, aircraft landing gear includes main legs, with at least one wheel rotatably mounted on the main legs to allow the aircraft to glide slowly on the ground upon landing. To decelerate the aircraft after landing, the landing gear includes a disc braking system comprising: at least one stator disc fixed relative to the main leg; at least one rotor disc rotating synchronously with the wheel; and at least one actuator configured to press the stator disc against the rotor disc to convert the kinetic energy of the wheel into heat energy distributed within the disc. The disc braking system consists of alternating stator discs and rotor discs and is referred to by those skilled in the art as a "radiator." The disc is typically made of a carbon-containing composite material. Such discs are known, for example, through patent application FR 3070191A1.

[0003] Each landing causes disc brakes to dissipate a significant amount of heat. In fact, an oxidation reaction occurs between the carbon disc and oxygen in the air. This oxidation reaction happens in the presence of oxygen, and the higher the temperature of the brake disc, the more intense the oxidation. Thermal oxidation causes the carbonaceous material to turn into gas. This damage degrades the mechanical properties of the disc and can even lead to its cracking. To reduce this degradation, the disc is coated with an anti-oxidation protective layer, but oxidation cannot be completely avoided.

[0004] Monitoring oxidation of the disc brake system is complex because the landing gear wheels must be removed. In practice, oxidation is visually inspected every time a landing gear wheel is replaced. The lack of visibility renders this visual inspection ineffective. Furthermore, if a disc breaks, the aircraft is brought to a standstill, which is also disadvantageous for the operator. Summary of the Invention

[0005] The objective of this invention is to provide a device for monitoring the thermal oxidation level of a disc brake system in an aircraft landing gear, which can be used by a non-professional operator under various conditions (rain, snow, night, etc.) during scheduled maintenance or when removing wheels from the landing gear. A second objective is to provide a robust and simple monitoring device. Finally, a third objective is to provide a monitoring device that can be used when the disc brake system is still hot after landing.

[0006] This invention relates to an apparatus for monitoring a disc braking system of an aircraft takeoff and landing gear, the disc braking system comprising at least one stator disc and at least one rotor disc configured to press against said stator disc, the monitoring apparatus comprising:

[0007] - A measuring tape that extends longitudinally and is configured to contact the outer periphery of the stator disk, the measuring tape including at least one visual information item related to a set perimeter of the stator disk;

[0008] - A first gripper, which is attached to the first end of the measuring tape; and

[0009] - A second gripper, which is connected to the second end of the measuring tape so as to tighten the measuring tape around the outer perimeter of the stator plate, thereby accurately determining the circumference of the stator plate.

[0010] Because of the device according to the invention, the measurement of the stator disc circumference can be performed conveniently and quickly by the operator. Furthermore, the presence of visual information items allows the operator to monitor the circumference to determine the presence and degree of oxidation. This makes it possible to monitor damage without removing the disc brake system.

[0011] Preferably, the measuring tape has a coefficient of thermal expansion of less than 15 × 10⁻⁶. -6 K -1 Made of materials that allow for accurate measurements even when the disc brake system is still hot.

[0012] Preferably, the tape measure is less than 10 mm wide, which allows it to be positioned between the two rotor discs to conform to the shape of the stator disc. In other words, this tape measure is particularly suitable for aviation applications.

[0013] According to a preferred aspect, the length of the measuring tape is between 1,300 mm and 2,500 mm to meet the average circumference of the stator disc of the disc brake system.

[0014] Preferably, at least one visual information item is in the form of a longitudinal portion of the measuring tape, including color and / or raised details. Therefore, the visual information is comprehensive and clearly identifiable, unlike traditional scales which are difficult to read at distances and under challenging conditions.

[0015] Preferably, the measuring tape has at least two visual information items, preferably consecutive, each related to two predetermined circumferences of the stator disk. This allows for determination of whether maintenance is required after the monitoring process.

[0016] According to a preferred aspect of the invention, the measuring tape has at least one slot into which a portion of the measuring tape is inserted to form a loop, the loop being configured to engage with the outer periphery of the stator disc. The presence of the slot advantageously allows the measuring tape to wrap around itself, forming a regular loop, thereby ensuring accurate circumference measurement.

[0017] Preferably, the measuring tape has at least one reading mark used to determine the visual information that needs to be considered. This provides guidance for the operator to read the tape.

[0018] Preferably, the measuring tape is made of metal to provide high robustness.

[0019] The present invention also relates to an assembly comprising a disc braking system for an aircraft landing gear and a monitoring device as previously described, the disc braking system comprising at least one stator disc and at least one rotor disc configured to press against the stator disc, the measuring tape being configured to contact the outer periphery of the stator disc.

[0020] Preferably, the stator disk is mounted between two rotor disks; even more preferably, the thickness of the stator disk is less than 10 mm. Preferably, at least one disk contains carbon.

[0021] The present invention also relates to a method for monitoring a disc braking system of an aircraft landing gear using a monitoring device as previously described, the disc braking system comprising at least one stator disc and at least one rotor disc configured to press against said stator disc, the monitoring method comprising:

[0022] - The step of connecting the measuring tape to the outer periphery of the stator plate.

[0023] - The steps of the operator applying traction on the first gripper and the second gripper to tighten the measuring tape around the outer periphery of the stator disc, and

[0024] - The step of reading visual information items related to the outer periphery of the stator disk on the measuring tape in order to determine the degree of degradation of the stator disk due to thermal oxidation. Attached Figure Description

[0025] The invention will be better understood after reading the following description given as an example and referring to the following drawings given as a non-limiting example, wherein the same reference numerals refer to similar objects.

[0026] Figure 1 This is a schematic diagram of a lifting device that includes a disc brake system.

[0027] Figure 2 This is a schematic diagram of a device for monitoring a disc brake system of a landing gear according to an embodiment of the present invention.

[0028] Figure 3 yes Figure 2 A close-up schematic diagram of the monitoring device shown.

[0029] Figure 4 yes Figure 2 A plan view of the longitudinal section of the measuring tape of the monitoring device shown.

[0030] Figure 5 This is a schematic diagram of a monitoring device used on a disc brake system.

[0031] It should be noted that the accompanying drawings illustrate the invention in detail in order to implement the invention; of course, the drawings can be used to better define the invention where appropriate. Detailed Implementation

[0032] This invention illustrates the thermal oxidation of a disc in a disc braking system for monitoring the takeoff and landing gear of an aircraft.

[0033] refer to Figure 1 The diagram shows a landing gear 1, including a main support leg 10 on which at least one wheel 11 equipped with a tire is rotatably mounted to allow the aircraft to glide slowly on the ground upon landing. To decelerate the aircraft after landing, the landing gear 1 includes a disc braking system 2, comprising: at least one stator disc fixed relative to the main support leg 10; at least one rotor disc rotating synchronously with the wheel 11; and at least one actuator 12 configured to press the stator disc against the rotor disc to convert the kinetic energy of the wheel 11 into heat energy dispersed within the disc through friction. Figure 5 As shown, the disc brake system 2 is composed of multiple stator discs 21 and multiple rotor discs 22 alternatingly. This disc brake system 2 is referred to by those skilled in the art as a "radiator". The stator discs 21 and rotor discs 22 are made of carbon-containing composite materials.

[0034] As mentioned earlier, carbon discs 21 and 22 undergo an oxidation reaction with oxygen in the air. This oxidation reaction can degrade the performance of discs 21 and 22 and lead to disc cracking. During monitoring of the disc braking system 2, it was found that the central discs 21 and 22 are the hottest and most susceptible to thermal oxidation damage. In fact, a decrease in the internal circumference of the central rotor disc 22 and a decrease in the external circumference of the central stator disc 21 can be observed.

[0035] To enable inspection without removing the disc brake system 2, the present invention relates to a monitoring device configured to measure, in particular, the outer circumference of the stator disk 21 located at the center of the disc brake system 2. Unlike the inner diameter, which is difficult to access without removing the wheels, the outer circumference of the stator disk 21 can be reliably measured while the disc brake system 2 is being assembled onto the aircraft. Advantageously, the measurement of the stator disk's outer circumference can be used to determine the degree of thermal oxidation.

[0036] In the prior art, devices for measuring the circumference of objects are already known. Existing measuring devices are in the form of simple measuring tapes, which are very rigid and cannot accurately conform to the outer circumference of cylindrical objects, especially stator disks. Furthermore, such measuring devices require the user to contact the object being measured, which is impossible for stator disks that may be exposed to high temperatures. Additionally, such measuring devices expand and become damaged upon contact with high-temperature objects, adversely affecting the accuracy of the measurement and its lifespan.

[0037] Furthermore, the purchased measuring device is too wide and cannot be placed on the outer periphery of the stator disk located between two large-diameter rotor disks, especially in cases of substantial degradation. Finally, such measuring devices are typically graduated in centimeters and millimeters, making it difficult for operators to perform measurements under harsh conditions (nighttime, rain, snow, etc.).

[0038] According to the present invention, reference Figure 2 The monitoring device 3 includes:

[0039] - Measuring tape 30, which extends longitudinally and is configured to contact the outer periphery of stator disk 21, the measuring tape 30 including at least one visual information item 41, 42, 43 related to a set perimeter of stator disk 21. Figure 2 (not shown in the image);

[0040] - A first gripper 31, which is connected to the first end of the measuring tape 30; and

[0041] - A second gripper 32 is attached to the second end of the measuring tape 30 so that the measuring tape 30 can be tightened around the outer periphery of the stator plate 21 in order to accurately determine the circumference of the stator plate 21.

[0042] In this example, the measuring tape 30 is made of metal to ensure its robustness, corrosion resistance, and wear resistance. Preferably, the measuring tape 30 is made of stainless steel. Undoubtedly, the measuring tape 30 can be made of other materials, especially composite materials containing fibers such as carbon fiber or ceramic fiber (glass, basalt, etc.) and materials with an organic matrix capable of withstanding temperatures of approximately 100°C.

[0043] Preferably, the coefficient of thermal expansion of the measuring tape 30 is less than 15 × 10⁻⁶. -6 K -1 The advantage of this property is that the operator can use the monitoring device 3 while the disc brake system 2 is still hot after landing. In other words, monitoring can be performed directly between landing and takeoff without stopping the aircraft.

[0044] In this example, refer to Figure 4The width D of the measuring tape 30 is less than 10 mm. This width allows the measuring tape 30 to be wound around the outer periphery of the stator disk 21 located between the two rotor disks 22. It is well known that the diameter of the stator disk 21 is smaller than the diameter of the rotor disks 22. Furthermore, this width D allows the measuring tape to be placed between two rotor disks spaced 10 mm apart, especially in cases of significant degradation due to thermal oxidation of the stator disk 21. The width of less than 10 mm allows the measuring tape 10 to fit firmly against the outer periphery of the stator disk 21.

[0045] The thickness of the measuring tape 30 allows it to bend and conform to the outer periphery of the stator disc 21. Preferably, the thickness of the measuring tape 30 is less than 0.6 mm to avoid a ridge effect that might occur when an overly stiff measuring tape attempts to bend to conform to the outer periphery. This ridge would distort the measurement results. The thickness of the measuring tape 30 is sufficient to ensure the strength of the measuring tape during use.

[0046] Preferably, the length of the measuring tape 30 is between 1,300 mm and 2,500 mm, in order to measure the circumference of any stator disc 21 of the disc brake system 2.

[0047] In this example, such as Figure 4 As shown, the measuring tape 30 includes several visual information items 41, 42, 43 related to the outer periphery of the stator disk 21, so as to visually indicate to the operator whether the measured outer periphery is acceptable (low-level degradation due to thermal oxidation) or reduced (strong / severe degradation due to thermal oxidation). Preferably, the visual information items 41, 42, 43 can indicate several degrees of degradation caused by thermal oxidation.

[0048] refer to Figure 4 The measuring tape 30 includes three visual information items 41, 42, and 43, which are presented as continuous longitudinal sections corresponding to low degradation (green longitudinal section), high degradation (yellow longitudinal section), and severe degradation (red longitudinal section), respectively. Each visual information item 41, 42, and 43 is associated with an outer perimeter value preferably set via feedback.

[0049] To prevent friction and wear, at least one visible information item 41, 42, 43 includes a raised portion laser-engraved. Preferably, as Figure 4 As shown, all visual information items 41, 42, and 43 have different bumps to allow for visual differentiation. The combination of color and bump for each visual information item 41, 42, and 43 makes them easier to read over long periods. Even if the color wears away, each visual information item 41, 42, and 43 can still be distinguished by its bumps. Advantageously, each visual information item 41, 42, and 43 can be recovered based on its different visual bumps.

[0050] According to a preferred aspect of the invention, each monitoring device 3 is specific to the landing gear 1 of each aircraft. Preferably, the monitoring device is stored in a case to protect it from kinks, impacts, grease, or oil. The case can be transported by a maintenance operator. Preferably, each monitoring device 3 is specifically identified by an identification plate provided on the grippers 31, 32.

[0051] like Figure 3 and Figure 4 As shown, the measuring tape 30 includes at least one slot 33, 34, into which a portion of the measuring tape 30 is inserted to form an annulus that contacts the outer periphery of the stator disk 21. Therefore, the measuring tape 30 conforms to the outer surface of the stator disk 21 to accurately measure its outer circumference.

[0052] In this implementation scheme, reference is still made to Figure 3 and Figure 4 The measuring tape 30 includes a first portion 30A and a second portion 30B. The first portion includes visible information items 41, 42, and 43, and the second portion includes two slots 33 and 34 to form a ring, as will be presented later. Reference Figure 3 When the annular shape is formed, only the longitudinal portion of the first part 30A of the measuring tape 30 is visible over the second part 30B. The first part 30A of the measuring tape 30 can slide relative to the second part 30B to adjust the diameter of the annular shape formed by the measuring tape. Preferably, the width D of the first part 30A is less than 6.5 mm so that the first part can be located between the two rotor disks 22.

[0053] Preferably, the second portion 30B includes a reading mark 35 to visually define the visual information 41, 42, 43 that must be considered, i.e., the visual information aligned with the reading mark 35. In this example, the reading mark 35 corresponds to one end of the slot 34, such as... Figure 4 As shown. Undoubtedly, other types of reading marks also apply.

[0054] Preferably, visual information items 41, 42, and 43 are defined to enable error prevention. If the positioning is incorrect, visual information 41, 42, and 43 will not appear on the reading mark 35.

[0055] like Figure 2 As shown, the grips 31 and 32 are preferably in the form of handles made of leather, so that the operator can easily and remotely tighten the tape measure 30 around the periphery without the risk of contacting the still hot disc brake system 2.

[0056] Optionally, at least one gripper 31, 32 is connected to the measuring tape 30. In this example, the loop formed by the measuring tape 30 cannot be removed due to the presence of the grippers 31, 32. In this example, each gripper 31, 32 is connected to the measuring tape 30 via a snap fastener, but other connection methods (hooks, clips, etc.) are also applicable. The measuring tape 30 and the reading head 34 thus form a loop that is not removable due to the grippers 31, 32, thereby making the measuring device 3 easier to use.

[0057] The present invention also relates to a method for monitoring the disc brake system 2 of an aircraft landing gear 1 using a monitoring device 3. In this embodiment, the operator wishes to check the outer perimeter of the stator disc 21 located at the center of the disc brake system 2.

[0058] First, the circumference of the ring formed by the measuring tape 30 is adjusted to be greater than the circumference of the stator disk 21 and passes through the rotor disk 2. Due to its small width, the measuring tape 30 can slide between the two rotor disks 22 without posing a risk of the operator coming into contact with the hot disc brake system 2. The method includes positioning the measuring tape 30 to engage with the outer periphery of the stator disk 21, particularly with the outer periphery of the stator disk 21 located between the two rotor disks 22.

[0059] The method includes the step of an operator applying traction on a first gripper 31 and a second gripper 32 to tighten the measuring tape 30 around the outer periphery of the stator disk 21. During this traction step, the circumference of the ring formed by the measuring tape 30 decreases. The measuring tape 30 slides into slots 33, 34 to adjust the circumference of the ring. Depending on the circumference of the stator disk 21, the visual information 41, 42, 43, positioned opposite the reading marks 35, also differs. Because the measuring tape 30 is very thin, it precisely conforms to the external shape of the stator disk 21, and the circumference measurement is accurate.

[0060] The method includes the step of reading relatively visible information items 41, 42, 43 around the outer periphery of the stator disk 21 on a measuring tape 30 in order to determine the extent of degradation of the stator disk 21 due to thermal oxidation.

[0061] In this example, under the condition of low degradation (first visual information 41), no maintenance steps are required. Under the condition of high degradation (second visual information 42), enhanced monitoring is planned. Under the condition of severe degradation (third visual information 43), maintenance operations are performed.

[0062] Advantageously, due to the low coefficient of thermal expansion of the measuring tape 30, the temperature of the stator disk 21 has only a slight impact on the measurement of the outer perimeter. The visual information items 41, 42, and 43, which are presented in the form of colors associated with the perimeter, facilitate rigorous monitoring under difficult conditions (rainy days, snowy days, nighttime, etc.).

[0063] Advantageously, the grippers 31 and 32 are spaced to release the measuring device 3 of the disc brake system 2 and pass through the rotor disc 22. The operator can widen the diameter of the annulus by applying a slight vibration to the grippers 31 and 32 to disengage the measuring device 3 from its measuring position.

Claims

1. A component comprising a disc braking system (2) and a monitoring device (3) for an aircraft landing gear (1), said disc braking system (2) comprising at least one stator disc (21) and at least one rotor disc (22) configured to press against said stator disc (21), characterized in that, The monitoring device (3) includes: - A longitudinally extending measuring tape (30), the measuring tape (30) including at least one visual information item (41, 42, 43) related to a set perimeter of the stator plate (21), the measuring tape (30) being configured to contact the outer perimeter of the stator plate (21); - A first gripper (31), which is connected to the first end of the measuring tape (30); and - A second gripper (32) is attached to the second end of the measuring tape (30) to tighten the measuring tape (30) around the outer periphery of the stator plate (21), thereby accurately determining the circumference of the stator plate (21).

2. The component as claimed in claim 1, characterized in that, The tape measure (30) is made of a material having a coefficient of thermal expansion less than 15 x 10 -6 K -1 .

3. The component as claimed in claim 1, characterized in that, The width (D) of the measuring tape (30) is less than 10 mm.

4. The component as claimed in claim 1, characterized in that, At least one visual information item (41, 42, 43) is in the form of a longitudinal portion of the measuring tape (30), the longitudinal portion including color and / or protrusion.

5. The component as claimed in claim 1, characterized in that, The measuring tape (30) has at least two visual information items (41, 42, 43) that are respectively associated with two set circumferences of the stator plate (21).

6. The component as claimed in claim 1, characterized in that, The measuring tape (30) has at least one slot (33, 34), a portion of which is inserted into the slot (33, 34) to form an annulus configured to contact the outer periphery of the stator disk (21).

7. The component as claimed in claim 1, characterized in that, The measuring tape (30) has at least one reading mark (35) for identifying the corresponding visual information item (41, 42, 43).

8. The component as claimed in claim 1, characterized in that, The measuring tape (30) is made of metal.

9. The component as claimed in claim 1, characterized in that, The stator disk (21) is installed between two rotor disks (22), and the thickness of the stator disk (21) is less than 10 mm.

10. A method for inspecting a disc brake system (2) of an aircraft landing gear (1) using a monitoring device (3) of any one of claims 1-9, said disc brake system (2) comprising at least one stator disc (21) and at least one rotor disc (22) configured to press against said stator disc (21), characterized in that, Monitoring methods include: - The step of connecting the measuring tape (30) to the outer periphery of the stator plate (21), -The operator applies traction on the first gripper (31) and the second gripper (32) to tighten the measuring tape (30) around the outer periphery of the stator disc (21), and - The step of reading visual information items (41, 42, 43) related to the outer periphery of the stator disk (21) on the measuring tape (30) in order to determine from them the condition of the stator disk (21) due to thermal oxidation.

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