Method of repairing an aircraft generator pressure switch assembly

Abstract

The application relates to the technical field of pressure switch repairing, and discloses an aircraft generator pressure switch assembly repairing method, which comprises the following steps: drilling off the pin; removing the switch assembly and a first sealing ring; removing a clamping ring and a first gasket; sequentially removing a sealing bushing, a piston, a spring and a second gasket, and removing a second sealing ring on the sealing bushing; welding a new micro switch with a wire, and fixing the micro switch to a mounting joint; using a packaging glue and a catalyst mixture to package the mounting joint, and curing the mounting joint according to selected conditions; sequentially mounting the second gasket, the spring, the piston and the sealing bushing to a pressure switch shell; mounting the first gasket and the clamping ring; mounting the first sealing ring to the switch assembly, and fastening the switch assembly to the shell; testing and adjusting the opening pressure and the closing pressure on a test bench; drilling a hole at a position deviated from an original pin hole, and mounting a new pin, and thus the repairing of the pressure switch is completed. The pressure switch with faults can be repaired instead of being replaced, so that the problem of the pressure switch fault is solved at a low cost.

Description

Technical Field

[0001] This application relates to the field of pressure switch repair technology, and more specifically, to a method for repairing pressure switch components of an aircraft generator. Background Technology

[0002] Currently, the main power source for most civil aircraft fleets is the Integrated Drive Generator (IDG), which provides 115V, 400Hz three-phase AC power. The operation of the various mechanical components within the IDD relies primarily on internal high-pressure lubricating oil, with a normal operating oil pressure range of 260Psi-300Psi. A pressure switch assembly acts as a monitoring element, continuously monitoring the lubricating oil pressure within the IDG. The switch opens at the normal operating pressure and closes when the oil pressure drops below 160Psi, activating the cockpit warning lights. The pilot can then disengage the IDD to prevent further damage.

[0003] Because the aircraft's integrated drive generator operates in a high-temperature, high-vibration lubricating oil environment, the pressure switch may malfunction after prolonged use. According to the manufacturer's repair manual, this switch cannot be repaired and must be replaced with a new one, which is expensive. Summary of the Invention

[0004] To address the technical problem that when an aircraft generator pressure switch malfunctions internally, it cannot be repaired and can only be replaced with a new part, this application proposes a method for repairing aircraft generator pressure switch components.

[0005] In view of this, this application proposes a repair method for an aircraft generator pressure switch assembly, comprising the following steps: drilling and removing the pin, cleaning the pin hole of the pressure switch housing; removing the switch assembly and the first sealing ring; removing the retaining ring and the first gasket; cleaning the end of the pressure switch housing, sequentially removing the sealing bushing, piston, spring, and second gasket, and removing the second sealing ring on the sealing bushing; removing the adhesive on the switch assembly, removing the screws, removing the adhesive on the mounting joint, and scrapping the old micro switch and wires; welding the new micro switch to the wires and fixing it to the mounting joint, and tightening it with screws to the specified torque; sealing the mounting joint with a mixture of encapsulating adhesive and catalyst, and curing it under selected conditions; performing an electrical performance test on the sealed switch assembly; sequentially installing the second gasket, spring, piston, and sealing bushing onto the pressure switch housing; installing the first gasket and retaining ring; installing the first sealing ring onto the switch assembly, and tightening the switch assembly to the housing; testing and adjusting the disconnect and close pressures on a test bench; drilling a hole offset from the original pin hole position and installing a new pin to complete the repair of the pressure switch.

[0006] In some feasible methods, the steps of cleaning the end of the pressure switch housing include: blowing the end of the pressure switch housing with compressed air at a pressure of less than 30 psi.

[0007] In some feasible approaches, after removing the sealing ring from the sealing bushing, the repair method may also include: retaining the unloose plug and bushing if the plug and bushing are not loose or damaged; or replacing the plug and bushing if the bushing or plug is damaged or the fit clearance is out of tolerance.

[0008] In some feasible methods, the steps of encapsulating the mounting joint with a mixture of encapsulant and catalyst, and curing under selected conditions, include: weighing the epoxy resin encapsulant and the matching fast catalyst at a weight ratio of 100:8, stirring and mixing them at room temperature until homogeneous to obtain a first gel-like mixture; curing the first gel-like mixture at 99°C-104°C for 175-185 minutes; and filling the cured first gel-like mixture into the mounting joint, maintaining an inclination angle of 45-60 degrees during the injection process.

[0009] In some feasible methods, the mounting joint is encapsulated using a mixture of encapsulant and catalyst, and the curing steps under selected conditions include: weighing epoxy resin encapsulant and a matching slow catalyst at a weight ratio of 100:7, stirring and mixing them at room temperature until homogeneous to obtain a second gel-like mixture; curing the second gel-like mixture at 65°C-70°C for 115-125 minutes; and filling the cured second gel-like mixture into the mounting joint, maintaining an inclination angle of 45-60 degrees during the injection process.

[0010] In some feasible methods, the steps for performing electrical performance tests on the packaged switch assembly include: applying a test current of 100mA to the switch assembly to perform a voltage drop test; measuring the resistance of the switch assembly with the switch contacts in the pop-out position using a multimeter; and measuring the insulation resistance of the switch assembly wires and housing using a 500V DC voltage.

[0011] In some feasible methods, after performing electrical performance tests on the packaged switch assembly, the repair method also includes: applying lubricant to the second sealing ring and installing the second sealing ring onto the sealing bushing.

[0012] In some feasible methods, the steps of securing the switch assembly to the housing include: tightening the switch assembly with a wrench, and then tightening it by 20-30 degrees with an angle wrench when the resistance of the switch assembly reaches the conducting state.

[0013] In some feasible methods, the steps of testing and adjusting the disconnect and close pressures on a test bench include: increasing the inlet pressure of the pressure switch assembly at a rate not exceeding 5 psi / s, monitoring the change in switch status, and recording the disconnect pressure value; after the inlet pressure rises to 200 psi, decreasing the inlet pressure of the pressure switch assembly at a rate not exceeding 3 psi / s, and recording the close pressure value.

[0014] In some feasible ways, if the pressure switch fails to meet the requirements, the number of shims can be increased or decreased until the test meets the requirements.

[0015] Compared with related technologies, this application has the following technical advantages:

[0016] This application proposes a repair method for an aircraft generator pressure switch assembly. This method allows for repair instead of replacement of faulty pressure switches, overcoming previous technological limitations. By employing a sealing technique, the method addresses the need for both sealing and insulation of the pressure switch contacts, ensuring reliable contact operation. This approach solves the pressure switch failure problem at a low cost, improving economic efficiency while maintaining reliability.

[0017] Additional aspects and advantages of this application will become apparent in the following description or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 A flowchart illustrating a method for repairing an aircraft generator pressure switch assembly according to one embodiment of this application is shown.

[0020] Figure 2 A schematic diagram of the pressure switch assembly and wrench in one embodiment of this application is shown;

[0021] Figure 3 A split schematic diagram of a pressure switch assembly according to one embodiment of this application is shown;

[0022] Figure 4 One of the schematic diagrams showing the installation state of the pressure switch assembly in one embodiment of this application is illustrated;

[0023] Figure 5 This is a second schematic diagram showing the installation state of a pressure switch assembly according to one embodiment of this application;

[0024] Figure 6 It shows Figure 5 AA view;

[0025] Figure 7 It shows Figure 5 BB view;

[0026] Figure 8 A schematic diagram of the assembled state of a pressure switch assembly according to one embodiment of this application is shown.

[0027] in, Figures 2 to 8 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0028] 10 Pins, 20 Switch Assembly, 30 First Sealing Ring, 40 Snap Ring, 50 First Gasket, 60 Sealing Bushing, 70 Second Sealing Ring, 80 Piston, 90 Spring, 100 Second Gasket, 110 Pressure Switch Housing, 130 First Plug, 140 Second Plug, 150 Bushing, 200 Mounting Connector, 210 Micro Switch, 220 Screw, 230 Adhesive, 240 Wire, 300 Pressure Switch Assembly, 400 Wrench. Detailed Implementation

[0029] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0031] The following reference Figures 1 to 8 This application describes a method for repairing an aircraft generator pressure switch assembly according to some embodiments.

[0032] like Figure 1 As shown, this application proposes a method for repairing an aircraft generator pressure switch assembly, comprising the following steps:

[0033] S102: Drill out the pin and clean the pin hole of the pressure switch housing; remove the switch assembly and the first sealing ring; remove the retaining ring and the first gasket; clean the end of the pressure switch housing, and remove the sealing bushing, piston, spring and second gasket in sequence, and remove the second sealing ring on the sealing bushing;

[0034] S104: Remove the adhesive from the switch assembly, remove the screws, remove the adhesive from the mounting connector, and discard the old micro switch and wires;

[0035] S106: After soldering the new micro switch to the wire, fix it to the mounting joint and tighten it with screws to the specified torque; seal the mounting joint with a mixture of encapsulating adhesive and catalyst, and cure it under the selected conditions; perform electrical performance tests on the encapsulated switch assembly;

[0036] S108: Install the second gasket, spring, piston, and sealing bushing onto the pressure switch housing in sequence; install the first gasket and retaining ring; install the first sealing ring onto the switch assembly and fasten the switch assembly to the housing; test and adjust the disconnect and close pressures on the test bench; drill a hole offset from the original pin hole position and install a new pin to complete the repair of the pressure switch.

[0037] This application provides a repair method for pressure switches with part numbers 713442 and 747736, which were originally expensive and could only be replaced with new parts. This method allows for detailed disassembly of the pressure switch components, elimination of specific faults, and completion of repairs, avoiding the high cost of direct replacement with new parts and effectively reducing maintenance costs.

[0038] Through a series of repair steps, including disassembling and cleaning the components of the pressure switch, replacing faulty components (such as microswitches and wires), resealing, performance testing, and adjusting pressure parameters, the faulty pressure switch can be restored to normal working performance, ensuring that it can accurately monitor the lubricating oil pressure inside the IDG and guarantee the safe operation of the aircraft's overall drive generator.

[0039] The repaired pressure switch assembly can function normally, promptly activating the cockpit warning light when the lubricating oil pressure is abnormal. This allows the pilot to disengage the integrated drive generator in a timely manner, preventing further damage to the integrated drive generator due to abnormal pressure, thereby ensuring the stable operation of the aircraft's power system and ultimately ensuring flight safety.

[0040] This solution proposes a complete repair method for aircraft generator pressure switch components, including detailed steps and operational requirements. It provides standardized process guidance for related maintenance work, which helps improve the quality and efficiency of maintenance work and reduce maintenance problems caused by non-standard operation.

[0041] In some embodiments provided in this application, the step of cleaning the end of the pressure switch housing includes: blowing the end of the pressure switch housing with compressed air at a pressure of less than 30 psi.

[0042] In this embodiment, the compressed air has a certain impact force, which can blow away dust, oil, metal shavings and other impurities attached to the end of the pressure switch housing, achieving a relatively thorough cleaning and ensuring that the surface of the housing end is clean, providing good conditions for the installation and normal operation of subsequent components.

[0043] By controlling the compressed air pressure to less than 30 psi, the cleaning effect can be guaranteed while preventing impact damage to the pressure switch housing caused by excessive pressure, such as housing deformation or damage to the surface coating. This protects the integrity and precision of the housing and extends its service life.

[0044] In some embodiments provided in this application, after removing the sealing ring on the sealing bushing, the repair method further includes: retaining the unloose plug and bushing if the plug and bushing are not loose or damaged; and replacing the plug and bushing with new ones if the bushing or plug is damaged or the fit clearance is out of tolerance.

[0045] In this embodiment, when the plugs and bushings are not loose or damaged, these components are retained, avoiding unnecessary replacements. Compared to indiscriminately replacing all components with new ones, this approach significantly reduces the number of new components required, thereby effectively lowering the overall cost of the pressure switch repair and improving the utilization efficiency of maintenance resources. The plugs and bushings that are not loose or damaged retain their original dimensional accuracy, sealing performance, and other key indicators in good condition. Retaining these components ensures that the pressure switch maintains a similar performance level after repair as before, without introducing new performance fluctuations or uncertainties due to component replacement, thus guaranteeing the stability and reliability of the pressure switch operation.

[0046] In some embodiments provided in this application, the steps of encapsulating the mounting joint with a mixture of encapsulating adhesive and catalyst and curing it under selected conditions include: weighing epoxy resin encapsulating adhesive and a matching fast catalyst at a weight ratio of 100:8, stirring and mixing them at room temperature until homogeneous to obtain a first gel-like mixture; curing the first gel-like mixture at 99℃-104℃ for 175 minutes-185 minutes; and filling the cured first gel-like mixture into the mounting joint, maintaining an inclination angle of 45 degrees-60 degrees during the injection process.

[0047] In this embodiment, the epoxy resin encapsulant and the matching fast catalyst are precisely weighed and mixed at a weight ratio of 100:8. This precise ratio control ensures that the encapsulant has stable and excellent physical and chemical properties after curing, such as suitable hardness, strength, and corrosion resistance, providing reliable sealing and protection for the installation joint.

[0048] Choosing a curing temperature of 99℃-104℃ within this range accelerates the curing reaction of the encapsulant, shortens curing time, and improves production efficiency. At the same time, this temperature range also prevents excessively high temperatures from degrading the encapsulant's performance or generating harmful substances, ensuring that the cured encapsulant meets the required performance.

[0049] The curing time should be controlled between 175 and 185 minutes. This timeframe ensures the encapsulant fully cures, allowing the molecular structure to stabilize and resulting in good mechanical and sealing properties. If the curing time is too short, the encapsulant may not fully cure, leading to poor performance; if the curing time is too long, it wastes energy and time, increasing production costs.

[0050] When filling the mounting joint with the cured first gel mixture, maintain an angle of 45-60 degrees. This angled injection method allows the adhesive to flow more smoothly into the mounting joint, reducing air ingress and effectively preventing the formation of air bubbles. The presence of air bubbles reduces the sealing performance and mechanical strength of the encapsulant, affecting the reliability of the mounting joint; this injection method effectively solves this problem.

[0051] In some embodiments provided in this application, the steps of encapsulating the mounting joint with a mixture of encapsulating adhesive and catalyst and curing it under selected conditions include: weighing epoxy resin encapsulating adhesive and a matching slow catalyst at a weight ratio of 100:7, stirring and mixing them at room temperature until homogeneous to obtain a second gel-like mixture; curing the second gel-like mixture at 65°C-70°C for 115-125 minutes; and filling the cured second gel-like mixture into the mounting joint, maintaining an inclination angle of 45-60 degrees during the injection process.

[0052] In this embodiment, the epoxy resin encapsulant and the matching slow-release catalyst are precisely weighed and mixed at a weight ratio of 100:7. This precise ratio ensures that the encapsulant possesses stable and expected physical and chemical properties after curing. For example, suitable bond strength ensures a tight bond between the encapsulant and the mounting joint, while good chemical resistance protects the internal components of the joint from external chemical corrosion, providing reliable basic protection for the mounting joint.

[0053] A 100:7 ratio achieves a good balance between properties such as adhesion, flexibility, and hardness. It avoids the problem of excessive catalyst leading to an overly hard and brittle encapsulant, and insufficient catalyst resulting in incomplete curing and poor performance, thus improving the overall performance of the encapsulant.

[0054] Choosing a curing temperature of 65℃-70℃ is considered a relatively low curing condition. This low-temperature curing method effectively avoids thermal damage to the mounting joints and surrounding components caused by high temperatures, such as thermal deformation and performance changes. Especially for temperature-sensitive electronic components or precision parts, low-temperature curing can maximize the protection of their performance and structural integrity, ensuring the stable operation of the entire system.

[0055] The curing time is controlled between 115 and 125 minutes. Combined with the characteristics of the slow-acting catalyst, this duration ensures the encapsulant undergoes a thorough curing reaction. The slow catalyst makes the reaction process more gradual and complete. After this curing period, the molecular structure of the encapsulant reaches a stable state, forming a cured layer with good mechanical and sealing properties. If the curing time is insufficient, the encapsulant will not be fully cured, resulting in insufficient strength and poor sealing; the time setting in this solution avoids this situation.

[0056] Maintaining a 45-60 degree tilt angle during adhesive application allows the adhesive to flow more smoothly into the mounting joint. The tilted position also ensures a more stable flow, reducing the likelihood of air ingress and effectively minimizing air bubbles. Air bubbles can negatively impact the sealing performance and mechanical strength of the encapsulating adhesive; this application method eliminates this risk, ensuring high-quality encapsulation.

[0057] In some embodiments provided in this application, the steps of performing electrical performance tests on the packaged switch assembly include: applying a test current of 100mA to the switch assembly to perform a voltage drop test; measuring the resistance of the switch assembly using a multimeter when the switch contacts are in the pop-out position; and measuring the insulation resistance of the switch assembly wires and housing using a 500V DC voltage.

[0058] In this embodiment, a voltage drop test is performed by applying a 100mA test current to the switch assembly, which can accurately measure the voltage loss generated when current passes through the switch assembly. The magnitude of the voltage drop directly reflects the resistance of the conductors inside the switch assembly and the connection quality of the contact points. Through this test, problems such as excessive conductor resistance and poor contact can be detected in a timely manner, ensuring that the switch assembly can efficiently and stably conduct current under normal operating current, thus guaranteeing the performance of the entire circuit system.

[0059] When the switch contacts are in the pop-out position, using a multimeter to measure the resistance of the switch assembly provides a comprehensive understanding of its resistance characteristics under different states. This includes not only the resistance of the conductors themselves but also contact resistance. Accurately measuring the resistance helps determine whether the switch assembly meets design requirements, ensuring it provides appropriate resistance parameters in the circuit, guaranteeing normal circuit operation and accurate signal transmission.

[0060] Measuring the insulation resistance of the wiring and housing of an electrical switch assembly using a 500V DC voltage can detect whether the insulation performance of the assembly is good. Good insulation performance is crucial for preventing electrical accidents. It ensures that no leakage current occurs between the wiring and housing under normal operating voltage and potential overvoltage conditions, avoiding the risk of electric shock and equipment damage. This test can also promptly identify problems such as aging, damage, and moisture absorption of insulation materials, allowing for appropriate repair or replacement measures to ensure the safe operation of the electrical system.

[0061] In some embodiments provided in this application, after performing electrical performance tests on the packaged switch assembly, the repair method further includes: applying lubricant to the second sealing ring and installing the second sealing ring onto the sealing bushing.

[0062] In this embodiment, the lubricant can fill the tiny uneven areas on the surface of the second sealing ring, making the contact between the second sealing ring and the sealing bushing tighter and more uniform. When the switch assembly is in operation, it can effectively prevent external dust, moisture, humidity and other impurities from entering the assembly, avoiding damage to the electrical performance of the switch assembly, such as causing short circuits or leakage, thereby ensuring the stable operation of the switch assembly.

[0063] Applying lubricant to the second sealing ring significantly reduces the friction between it and the sealing bushing, making it easier to install. This not only improves installation efficiency and reduces the time and labor costs required, but also prevents damage or deformation of the second sealing ring due to forced installation, ensuring its integrity and sealing performance.

[0064] In some embodiments provided in this application, the step of fastening the switch assembly to the housing includes: tightening the switch assembly with a wrench, and when the resistance of the switch assembly reaches the conducting state, tightening it by 20-30 degrees with an angle wrench.

[0065] In this embodiment, the switch assembly is first tightened with a wrench to initially fix it. When the resistance reaches the conduction state, it indicates that the assembly has achieved basic electrical connection, ensuring normal current conduction and avoiding problems such as voltage fluctuations and signal interference due to poor contact, thus ensuring that the switch assembly can function stably.

[0066] Using an angle wrench to tighten the screws by an additional 20-30 degrees further enhances the mechanical connection between the switch assembly and the housing. This precise angle control prevents over-tightening from damaging the assembly or housing, while ensuring a tight connection and effectively resisting external forces such as vibration and impact, preventing the assembly from loosening or falling off.

[0067] In some embodiments provided in this application, the steps of testing and adjusting the disconnect and close pressures on a test bench include: increasing the inlet pressure of the pressure switch assembly at a rate not exceeding 5 psi / s, monitoring the change in the switch state, and recording the disconnect pressure value; after the inlet pressure rises to 200 psi / square inch, decreasing the inlet pressure of the pressure switch assembly at a rate not exceeding 3 psi / s, and recording the close pressure value.

[0068] In this embodiment, pressurizing at a rate not exceeding 5 psi / s allows for a smooth pressure increase, ensuring a stable state transition of the switch assembly during pressure changes. This accurately captures the moment of disconnection, thereby precisely recording the disconnection pressure value. Similarly, controlling the depressurization rate to not exceed 3 psi / s ensures clear state changes of the switch as the pressure decreases, accurately recording the closing pressure value and providing reliable data for subsequent analysis.

[0069] A slow rate of pressure change avoids shock damage to the switch components caused by sudden pressure increases or decreases, extending component lifespan and reducing testing costs. Simultaneously, it prevents sudden pressure changes from triggering malfunctions in other components of the test bench, ensuring the safe and stable operation of the entire testing system.

[0070] By accurately measuring and adjusting the opening and closing pressures, we ensure that the switch components operate reliably within the specified pressure range, improve product performance consistency, enable them to better adapt to different working conditions in practical applications, reduce the occurrence of failures, and enhance the product's competitiveness in the market.

[0071] In some embodiments provided in this application, if the pressure switch fails to meet the requirements, the number of shims is increased or decreased until the test meets the requirements.

[0072] In this embodiment, adding or removing shims allows for flexible adjustment of the internal structure of the pressure switch. Adding shims increases the preload of the internal spring, thereby increasing the set values ​​for the opening and closing pressures; removing shims has the opposite effect. This method allows for precise fine-tuning of the switch's pressure parameters to meet different operating conditions and design requirements. Furthermore, the operation is simple and convenient, requiring no complex tools or techniques, enabling rapid adjustment and retesting, effectively shortening the debugging cycle, reducing maintenance costs, and ensuring the pressure switch functions stably and reliably in various application scenarios, thus guaranteeing the normal operation of the entire system.

[0073] In specific embodiments, such as Figure 2 , Figure 3 and Figure 4 As shown, the pressure switch assembly 300 is disassembled using a wrench 400. The pressure switch assembly 300 includes a pin 10, a switch assembly 20, a first sealing ring 30, a retaining ring 40, a first gasket 50, a sealing bushing 60, a second sealing ring 70, a piston 80, a spring 90, a second gasket 100, a pressure switch housing 110, a first plug 130, a second plug 140, a bushing 150, a mounting connector 200, a micro switch 210, a screw 220, adhesive 230, and a wire 240.

[0074] The repair process for the aircraft generator pressure switch assembly is as follows:

[0075] I. Disassembly of the pressure switch assembly

[0076] Caution: Exercise caution when milling, drilling, or heating to prevent damage to the housing area around the pin.

[0077] 1. Drill the pin with a 1.5875 mm diameter drill bit and clean the pin hole on the pressure switch housing.

[0078] Note: When drilling around the pin hole of the pressure switch assembly, the drilling depth should not exceed 1.0160 mm.

[0079] 2. Use a wrench to remove the switch assembly and remove the first sealing ring.

[0080] 3. Remove the retaining ring and the first washer.

[0081] 4. Use compressed air to blow air into the end of the pressure switch housing. Remove the sealing bushing, piston, spring, and second gasket, and remove the second sealing ring from the sealing bushing.

[0082] 5. Do not remove the plug or bushing unless it is loose or damaged.

[0083] II. Disassembling the switch assembly

[0084] 1. Remove the adhesive Stycast2651 from the switch assembly.

[0085] 2. Remove the screws.

[0086] 3. Clean the adhesive residue from the Stycast2651 connector.

[0087] 4. Discarded micro switches and wires.

[0088] III. Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown in Table 1, the installation steps for the ignition switch assembly are as follows:

[0089] 1. Solder the new micro switch to the new wire.

[0090] 2. Secure the micro switch to the mounting connector. Tighten the mounting screws to a torque of 1.6-1.8 psi.

[0091] 3. According to Figure 4 and Figure 6 The dimensions are achieved using Stycast 2651 adhesive.

[0092] 4. Stycast 2651 adhesive and catalyst should be used together. Stycast 2651 adhesive and catalyst 11 should be mixed at a weight ratio of 100:8. Stycast 2651 adhesive and catalyst 9 should be mixed at a weight ratio of 100:7. The adhesive and catalyst must be completely mixed and have a uniform color.

[0093] Note: The mixture is suitable for use within 4 hours.

[0094] 5. Carefully fill the installation joint with the mixture, minimizing air bubbles. Follow the instructions... Figure 4 and Figure 6 Encapsulate the material to the correct size to prevent mixture from spilling or interfering with the threads.

[0095] 6. If catalyst 11 is used, the mixture needs to be cured at 99℃-104℃ for 3 hours. If catalyst 9 is used, the mixture needs to be cured at 65℃-70℃ for 2 hours.

[0096] 7. Remove the packaging mold and inspect the packaging material; the curing agent must be free of air bubbles.

[0097] 8. Perform the following checks:

[0098] When a current of 100mA is applied to the switch assembly, the voltage drop should not exceed 0.04V.

[0099] When the switch contacts are in the pop-out position, measure the resistance of the switch assembly; the resistance value should be greater than 2MΩ.

[0100] The insulation resistance of the switch assembly wires and housing should be measured using a 500V DC voltage. The insulation resistance value should not be less than 200MΩ.

[0101] Table 1

[0102]

[0103] IV. Assemble the pressure switch

[0104] 1. Apply Dow Corning Number 7 (silicone-based grease / sealant) to the second sealing ring and install it onto the sealing bushing. Install the second gasket, spring, piston, and sealing bushing onto the pressure switch housing.

[0105] Note: The maximum number of gaskets is 3.

[0106] 2. Install the first gasket and retaining ring onto the pressure switch housing.

[0107] 3. Install the first sealing ring onto the ignition switch assembly. Tighten the ignition switch assembly with a wrench. Start calculating when the resistance of the ignition switch assembly reaches the conducting state, and tighten it by 25±5 degrees.

[0108] 4. Install the pressure switch onto the pressure switch test bench. Slowly increase the inlet pressure of the pressure switch assembly; the assembly must disconnect before the pressure reaches 160 psi. Once the pressure reaches 200 psi, slowly decrease the inlet pressure of the pressure switch assembly; the assembly must close before the pressure reaches 120 psi.

[0109] 5. Repeat the test procedure in step 4. If the pressure switch does not meet the requirements, increase or decrease the number of gaskets according to the above scheme until the test meets the requirements.

[0110] like Figure 8As shown in Table 2, drill holes for the pressure switch according to the dimensions, ensuring that the new holes are not within a 30-degree range of the old holes. Install the new pins to complete the assembly of the pressure switch.

[0111] Table 2

[0112]

[0113] In this application, the term "multiple" refers to two or more unless otherwise expressly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0114] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0115] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for repairing an aircraft generator pressure switch assembly, characterized in that, Includes the following steps: Drill out the pin and clean the pin hole of the pressure switch housing; remove the switch assembly and the first sealing ring; remove the retaining ring and the first gasket; clean the end of the pressure switch housing, and remove the sealing bushing, piston, spring and second gasket in sequence, and remove the second sealing ring on the sealing bushing; Remove the adhesive from the switch assembly, remove the screws, remove the adhesive from the mounting connector, and discard the old micro switch and wires; After soldering the new micro switch to the wire, fix it to the mounting joint and tighten it with screws to the specified torque; seal the mounting joint with a mixture of encapsulating adhesive and catalyst, and cure it under the selected conditions. Perform electrical performance tests on the packaged switch assembly; Install the second gasket, spring, piston, and sealing bushing onto the pressure switch housing in sequence; install the first gasket and retaining ring; install the first sealing ring onto the switch assembly and tighten the switch assembly to the housing; test and adjust the disconnect and close pressures on the test bench; drill a hole offset from the original pin hole position and install a new pin to complete the repair of the pressure switch.

2. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, The step of cleaning the end of the pressure switch housing includes: blowing the end of the pressure switch housing with compressed air at a pressure of less than 30 psi.

3. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, After removing the sealing ring from the sealing bushing, the repair method further includes: If the plugs and bushings are not loose or damaged, retain the loose plugs and bushings; If the bushing or plug is damaged or the clearance is out of tolerance, replace it with a new plug or bushing.

4. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, The step of encapsulating the mounting joint with a mixture of encapsulating adhesive and catalyst, and curing it under selected conditions, includes: The epoxy resin encapsulant and the matching fast catalyst were weighed at a weight ratio of 100:8 and stirred at room temperature until homogeneous to obtain the first gel-like mixture. The first gel-like mixture was cured at 99°C-104°C for 175-185 minutes; Fill the cured first gel-like mixture into the installation joint, maintaining an inclination angle of 45-60 degrees during the injection process.

5. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, The step of encapsulating the mounting joint with a mixture of encapsulating adhesive and catalyst, and curing it under selected conditions, includes: The epoxy resin encapsulant and the matching slow catalyst were weighed at a weight ratio of 100:7 and stirred at room temperature until homogeneous to obtain a second gel-like mixture. The second gel-like mixture was cured at 65°C-70°C for 115-125 minutes; Fill the installation joint with the cured second gel mixture, maintaining a tilt angle of 45-60 degrees during the injection process.

6. The method for repairing the pressure switch assembly of an aircraft generator according to any one of claims 1 to 5, characterized in that, The step of performing electrical performance testing on the packaged switch assembly includes: A test current of 100mA was applied to the switch assembly to perform a voltage drop test; When the switch contacts are in the pop-out position, use a multimeter to measure the resistance of the switch assembly; The insulation resistance of the switch assembly wires and housing was measured using a 500V DC voltage.

7. The method for repairing the pressure switch assembly of an aircraft generator according to any one of claims 1 to 5, characterized in that, After performing electrical performance tests on the packaged switch assembly, the repair method further includes: Apply lubricant to the second sealing ring and install it onto the sealing bushing.

8. The method for repairing the pressure switch assembly of an aircraft generator according to any one of claims 1 to 5, characterized in that, The step of securing the switch assembly to the housing includes: Tighten the ignition switch assembly with a wrench. When the resistance of the ignition switch assembly reaches the conducting state, tighten it by another 20-30 degrees with an angle wrench.

9. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, The steps of testing and adjusting the disconnection and closing pressures on the test bench include: Increase the inlet pressure of the pressure switch assembly at a rate not exceeding 5 psi / s, monitor the change in switch status, and record the disconnection pressure value; After the inlet pressure is increased to 200 psi, the inlet pressure of the pressure switch assembly is reduced at a rate not exceeding 3 psi / s, and the closing pressure value is recorded.

10. The method for repairing the pressure switch assembly of an aircraft generator according to claim 1, characterized in that, If the pressure switch fails to meet the requirements, increase or decrease the number of shims until the test meets the requirements.

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