A method for installing a thermocouple for measuring the temperature of an aircraft engine bearing end surface

Abstract

The present application belongs to the technical field of measuring the end surface temperature of bearings in aircraft engines, and specifically relates to a method for installing a thermocouple for measuring the end surface temperature of bearings in aircraft engines. A test hole is designed to be processed on the end surface of the bearing, and a temperature-sensing head is made on the periphery of the hot junction of a T-type fluorine-wrapped thermocouple using a mold and high-temperature solder. The temperature-sensing head is designed to be installed in the test hole using a processed hollow tube, and the leads of the T-type fluorine-wrapped thermocouple are fixed to the wall using a spot welding process to complete the installation and measure the end surface temperature of the bearing in the aircraft engine.

Description

Technical Field

[0001] The present application belongs to the technical field of measuring the end surface temperature of a bearing in an aircraft engine, and specifically relates to a method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine. Background Art

[0002] There are a large number of bearings in aircraft engines. By using bearings to transmit force, accurately obtaining the temperatures of the front and rear end faces of the bearings and obtaining the temperature gradients of the inner and outer rings of the bearings can provide important data support for the analysis and location of transmission system faults in aircraft engines, as well as for the design and improvement of transmission systems in aircraft engines.

[0003] Currently, most temperature measurements are performed using armored thermocouples installed on the bearing end face using the "wall temperature couple direct installation method". Figure 1 As shown, the space available for installation on the bearing end face is small, making it difficult to reliably install the armored thermocouple. In addition, the armored thermocouple is relatively rigid and has a small bending curvature, making it impossible to reliably fix it to the wall in high-risk narrow spaces such as near aircraft engine rotors or in complex lead paths with continuous changes.

[0004] This application is proposed in view of the above-mentioned technical defects.

[0005] It should be noted that the disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0006] The purpose of the present application is to provide a method for installing a thermocouple for measuring the temperature of a bearing end surface in an aircraft engine, so as to overcome or alleviate at least one of the technical defects of the known ones.

[0007] The technical solution of this application is:

[0008] A method for installing a thermocouple for measuring the temperature of a bearing end surface in an aircraft engine, comprising:

[0009] Machine a test hole with a diameter of 2mm and a depth of not less than 4mm on the bearing end face;

[0010] The positive and negative electrode wires of the T-type fluorine-clad thermocouple measuring end are made into hot junctions through argon arc welding;

[0011] A mold is made, the mold comprising two opposing halves connected by bolt fasteners, with a casting hole symmetrically machined therebetween with a diameter of 2 mm and a depth of 2 mm;

[0012] Fill the casting hole with high-temperature solder, use acetylene flame for local heating to melt the high-temperature solder, insert the hot junction into the casting hole, and quickly cool the mold with pure water to solidify the high-temperature solder around the hot junction to form a temperature-sensing head. Remove the bolt fasteners on the mold and take out the temperature-sensing head.

[0013] Cut a section of hollow tube with an outer diameter of 2mm, a wall thickness of 0.2mm, and a length of a+3mm, where a is the depth of the test hole. Draw a cutting line on the hollow tube, which is a-2mm away from one end of the hollow tube. Use a grinding machine with a cutting blade with a diameter of 20mm and a thickness of 0.5mm to cut axially symmetrically from the other end of the hollow tube to the cutting line. Bend the cut halves of the hollow tube and clamp them flat with flat-mouth pliers. The normal direction of the two flat halves is in the same direction as the centerline of the hollow tube.

[0014] Put the cylindrical part of the hollow tube onto the T-type fluorine-encapsulated thermocouple, insert the temperature-sensing head into the test hole, and spot weld the two flat halves of the hollow tube to the bearing end face using a capacitive spot welding device, so that the cylindrical part of the hollow tube is pressed tightly against the temperature-sensing head;

[0015] Fill the sealant between the cylindrical part of the hollow tube and the T-type fluorine-coated thermocouple and cure it;

[0016] The lead wires of the T-type fluorine-clad thermocouple are fixed to the wall using spot welding technology.

[0017] According to at least one embodiment of the present application, the above-mentioned method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine further includes:

[0018] Use absorbent cotton and acetone to clean the test hole and the end surface around the test hole to remove iron filings and dirt.

[0019] According to at least one embodiment of the present application, the above-mentioned method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine further includes:

[0020] Use protective stickers to protect the bearing balls / rollers near the test holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of installing armored thermocouples using the direct wall temperature couple installation method;

[0022] Figure 2 Schematic diagram of machining a test hole on a bearing end face according to an embodiment of the present application;

[0023] Figure 3 This is a schematic diagram of making the positive and negative electrode wires of the T-type fluorine-coated thermocouple measuring end into thermal junctions provided by an embodiment of the present application;

[0024] Figure 4 is a schematic diagram of a mold provided in an embodiment of the present application;

[0025] Figure 5 is a schematic diagram of a temperature sensing head provided in an embodiment of the present application;

[0026] Figure 6 This is a schematic diagram of cutting and processing a hollow tube provided in an embodiment of the present application;

[0027] Figure 7 Schematic diagram of a method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine according to an embodiment of the present application;

[0028] in:

[0029] 1-Bearing; 2-T-type fluorine-coated thermocouple; 3-Mold; 4-Temperature sensing head; 5-Hollow tube.

[0030] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be understood as limitations on this patent. DETAILED DESCRIPTION

[0031] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0032] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0033] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0034] The following is combined with Figures 1 to 7 The following is a detailed description of the thermocouple installation method for measuring the end surface temperature of the bearing in the aircraft engine provided in this application:

[0035] A test hole with a diameter of 2 mm and a depth of not less than 4 mm is machined on the end face of the bearing 1. The end face referred to here can be the front and rear end faces of the inner and outer rings, such as Figure 2 As shown;

[0036] Use absorbent cotton and acetone to clean the test hole and the end surface around the test hole to remove iron filings and dirt, and ensure that the test hole and the surrounding area are clean;

[0037] Use protective stickers to protect the bearing balls / rollers near the test holes to prevent excess debris generated during the test installation process from entering the bearing raceway, but leave the test holes and the end faces around them exposed for easy installation.

[0038] According to the temperature measurement range and sensor accuracy requirements, combined with the fact that the measured end face of the bearing is close to the rotor and the space is small, and it needs to be reliably fixed to the wall along the complex lead path, and at the same time it needs to have good oil resistance and the ability to bend with large curvature, a T-type fluorine-clad thermocouple 2 is selected, with specifications of T-type-FF-Φ0.3-I level and an outer diameter of no more than 1.5mm;

[0039] The positive and negative electrode wires of the T-type fluorine-coated thermocouple 2 measuring ends are made into hot junctions by argon arc welding. The hot junctions are required to be as close to the insulation sheaths of the two wires as possible, that is, the exposed wires are as short as possible. Figure 3 As shown;

[0040] Make a mold 3 for making the temperature sensing head 4. To facilitate the separation and removal of the temperature sensing head 4 after casting, the mold 3 is designed to include two opposite halves connected by bolt fasteners. A casting hole with a diameter of 2mm and a depth of 2mm is symmetrically machined between the two halves. Figure 4 As shown;

[0041] Based on the temperature measurement range, select high-temperature solder with a melting point higher than the upper temperature measurement limit and good thermal conductivity. Place an appropriate amount of high-temperature solder into the casting hole. Use an acetylene flame to locally heat the mold 3 to melt the high-temperature solder. Slowly insert the hot junction end into the liquid high-temperature solder and ensure that the hot junction touches the bottom. Use pure water to quickly cool the mold 3 base to solidify the high-temperature solder into the temperature sensing head 4. Remove the bolt fasteners, remove the temperature sensing head 4, and partially grind the temperature sensing head 4 to ensure the size.

[0042] Cut a hollow tube 5 with an outer diameter of 2mm, a wall thickness of 0.2mm, and a length of a+3mm, where a is the depth of the test hole. The material composition of the hollow tube 5 is as close as possible to the material composition of the inner and outer rings of the bearing 1. Draw a cutting line on the hollow tube 5, which is a-2mm away from one end of the hollow tube 5. Use a grinder with a cutting disc of 20mm in diameter and 0.5mm in thickness to cut axially symmetrically from the other end of the hollow tube 5 to the cutting line. Grind and remove burrs and sharp edges of the cut hollow tube 5. Bend the cut halves of the hollow tube 5 and clamp them flat with flat-mouth pliers. The normal direction of the two flat halves is in the same direction as the center line of the hollow tube 5, as shown in the figure. Figure 6 As shown;

[0043] Put the cylindrical part of the hollow tube 5 onto the T-type fluorine-coated thermocouple 2, insert the temperature-sensing head 4 into the test hole, and spot weld the two flat halves of the hollow tube 5 to the bearing end surface with a capacitive spot welding device, so that the cylindrical part of the hollow tube 5 is tightly pressed against the temperature-sensing head 4, ensuring that the plane of the temperature-sensing head 4 is in close contact with the bottom of the test hole, so as to achieve reliable installation of the temperature-sensing head 4. Figure 7 As shown;

[0044] Since the end face of the bearing 1 in the aircraft engine is in an oil-gas mixture environment, there is a temperature difference between the temperature of the oil-gas mixture and the temperature of the end face of the bearing 1. In order to prevent the oil-gas mixture from splashing into the gap between the cylindrical part of the hollow tube 5 and the T-type fluorine-coated thermocouple 2 and affecting the temperature measurement accuracy, a sealant that meets the requirements of oil resistance and temperature resistance is selected and cured in the gap;

[0045] The lead wire of the T-type fluorine-clad thermocouple 2 is fixed to the wall by spot welding technology, and the installation is completed to measure the end surface temperature of the bearing in the aircraft engine.

[0046] In the method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine disclosed in the above embodiment, a test hole is designed to be processed on the end surface of the bearing 1, a temperature sensing head 4 is made on the periphery of the hot junction of the T-type fluorine-clad thermocouple 2 using a mold 3 with high-temperature solder, and the temperature sensing head 4 is designed to be installed in the test hole using a processed hollow tube 5. The lead of the T-type fluorine-clad thermocouple 2 is then fixed to the wall using a spot welding process to complete the installation. The end surface temperature of the bearing in the aircraft engine is measured, which can overcome the defect of the existing armored thermocouple that uses the "wall temperature couple direct installation method" to be installed on the bearing end surface for temperature measurement.

[0047] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0048] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine, characterized in that: include: A test hole with a diameter of 2 mm and a depth of not less than 4 mm is machined on the end face of the bearing (1); The positive and negative electrode wires of the measuring end of the T-type fluorine-coated thermocouple (2) are made into a hot junction by an argon arc welding mechanism; A mold (3) is made, wherein the mold (3) comprises two opposite halves connected by a bolt fastener and having a casting hole with a diameter of 2 mm and a depth of 2 mm symmetrically machined therebetween; Fill the casting hole with high-temperature solder, locally heat it with an acetylene flame to melt the high-temperature solder, insert the hot junction into the casting hole, quickly cool the mold (3) with pure water to solidify the high-temperature solder around the hot junction to form a temperature-sensing head (4), remove the bolt fasteners on the mold (3), and take out the temperature-sensing head (4); Cut a section of a hollow tube (5) with an outer diameter of 2 mm, a wall thickness of 0.2 mm, and a length of a+3 mm, wherein a is the depth of the test hole, draw a cutting cutoff line on the hollow tube (5), and the cutting cutoff line is a-2 mm away from one end of the hollow tube (5). Use a grinding machine to cut the other end of the hollow tube (5) symmetrically along the axis to the cutting cutoff line using a cutting blade with a diameter of 20 mm and a thickness of 0.5 mm. Bend the cut halves of the hollow tube (5) and clamp them flat with flat-mouth pliers, with the normal direction of the two flat halves being in the same direction as the center line of the hollow tube (5). The cylindrical portion of the hollow tube (5) is placed on the T-type fluorine-coated thermocouple (2), the temperature sensing head (4) is inserted into the test hole, and the two flat halves of the hollow tube (5) are spot welded to the bearing end surface using a capacitive spot welding device, so that the cylindrical portion of the hollow tube (5) is tightly pressed against the temperature sensing head (4); Filling sealant between the cylindrical portion of the hollow tube (5) and the T-shaped fluorine-coated thermocouple (2) and curing the sealant; The lead wire of the T-type fluorine-clad thermocouple (2) is fixed to the wall by spot welding.

2. The method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine according to claim 1, characterized in that: Also includes: Use absorbent cotton and acetone to clean the test hole and the end surface around the test hole to remove iron filings and dirt.

3. The method for installing a thermocouple for measuring the end surface temperature of a bearing in an aircraft engine according to claim 1, characterized in that: Also includes: Use protective stickers to protect the bearing balls / rollers near the test holes.

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