A filter cartridge for an aircraft lubrication system

Abstract

The utility model discloses a kind of oil filter filter element for aircraft lubricating system, including coaxially arranged outer end cap (1) and inner end cap (2), clamping fixed cylindrical skeleton (3) between two end caps and filter layer assembly (4) set on the outer periphery of skeleton. Filter layer assembly (4) is sequentially laminated by metal mesh layer (6), non-woven fabric layer (7) and glass fiber paper layer (8) along radial direction, and is sealed by O-ring (5) at two ends. The structure forms unidirectional filtering channel from outside to inside, with the characteristics of high filtering precision, low pressure loss, convenient assembly and maintenance, suitable for bypass filtration of aero-engine lubricating system.

Description

Technical Field

[0001] This utility model relates to the technical field of lubricating oil filter elements for aircraft lubrication systems, and in particular to a lubricating oil filter element for aircraft lubrication systems. Background Technology

[0002] Oil filters in aircraft lubrication systems are crucial for ensuring flight safety. However, traditional filters have several problems: firstly, they suffer from large initial pressure drops, leading to energy loss; secondly, their filtration accuracy is low, making it difficult to effectively intercept small particulate impurities. Furthermore, existing filters are prone to deformation and damage under extreme temperatures, lack sufficient strength, and are easily destroyed when there is a large internal and external pressure difference. They also have low dirt-holding capacity and short lifespan, requiring frequent replacement and increasing maintenance costs. Simultaneously, their low filtration ratio fails to meet the stringent requirements of aircraft lubrication systems for lubricant cleanliness, impacting aircraft reliability and safety. Utility Model Content

[0003] The purpose of this invention is to provide an oil filter element for an aircraft lubrication system, thereby solving the aforementioned problems existing in the prior art.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] An oil filter element for an aircraft lubrication system, the filter element comprising:

[0006] The outer and inner end caps are arranged coaxially.

[0007] A cylindrical skeleton extending axially between the outer end cap and the inner end cap;

[0008] A filter layer assembly fitted around the outer periphery of the skeleton and composed of multiple layers of filter media stacked radially;

[0009] And a seal located between the outer end cap and the inner end cap, used to seal both ends of the filter layer assembly;

[0010] The inner circumferential surface of the filter layer assembly is attached to the outer circumferential surface of the skeleton, and the two ends of the filter layer assembly are respectively clamped and fixed between the axial end faces of the outer end cover and the inner end cover, forming a unidirectional filter channel that flows radially from the outside to the inside.

[0011] In some specific embodiments, the sealing element is an O-ring, which is embedded in the annular sealing grooves opened on the side of the outer end cap and the inner end cap facing the filter layer assembly, and simultaneously presses the two end faces of the filter layer assembly.

[0012] In some specific embodiments, the frame is a perforated metal cylinder with holes evenly distributed on the cylinder wall to support the filter layer assembly and maintain oil flow.

[0013] In some specific embodiments, the filter layer assembly includes, from the outside in, the following components:

[0014] The outer circumferential surface of the metal mesh layer is radially aligned with the inner circumferential surface of the outer end cap;

[0015] The non-woven fabric layer has its inner circumferential surface adhered to the inner circumferential surface of the metal mesh layer.

[0016] The inner circumferential surface of the fiberglass paper layer is attached to the inner circumferential surface of the nonwoven fabric layer and to the outer circumferential surface of the skeleton.

[0017] In some specific embodiments, the metal mesh layer, non-woven fabric layer, and fiberglass paper layer are bonded together in a dotted manner with hot melt adhesive before being fitted onto the skeleton.

[0018] In some specific embodiments, both the outer end cap and the inner end cap are aluminum alloy annular plates, which are coaxially arranged opposite each other, and each has a flange on its radial outer edge to cover the outer periphery of the end of the filter layer assembly.

[0019] In some specific embodiments, the outer end cap and the inner end cap are two sets; they are respectively disposed at both ends of the skeleton and the filter layer assembly, and the skeleton and the filter layer assembly are axially clamped.

[0020] In some specific embodiments, radial flanges are provided at both ends of the skeleton, and the flanges are embedded in the central holes of the outer end cap and the inner end cap to form a positioning fit.

[0021] In some specific embodiments, the metal mesh is made of stainless steel; the non-woven fabric is made of polyester non-woven fabric; and the O-ring is made of rubber.

[0022] The beneficial effects of this utility model are as follows: This utility model discloses a lubricating oil filter element for aircraft lubrication systems, including an outer end cap and an inner end cap arranged coaxially, with a cylindrical skeleton clamped and fixed between the two end caps and a filter layer assembly sleeved on the outer periphery of the skeleton; the filter layer assembly is composed of a metal mesh layer, a non-woven fabric layer, and a glass fiber paper layer stacked radially, and both ends are sealed with O-rings. This utility model, through innovative design of optimized structure and materials, provides a high-performance, high-reliability lubricating oil filter element for aircraft lubrication systems. Compared with traditional filter elements, it has superior filtration performance, significantly improved filtration ratio and dirt holding capacity, effectively removing impurities from lubricating oil and ensuring the cleanliness of the aircraft lubrication system. Simultaneously, the initial flow resistance is reduced, minimizing energy loss and improving system operating efficiency. The filter element's strength and resistance to high and low temperatures are enhanced, adapting to extreme temperatures and large flow impacts, ensuring stable operation in harsh environments. Furthermore, the modular structure and compatible design facilitate quick replacement, reducing maintenance time and costs, and significantly improving aircraft maintenance efficiency and uptime. Overall, this invention effectively addresses the shortcomings of existing technologies, significantly improves the performance and reliability of aircraft lubrication systems, is of great significance for ensuring flight safety, and has broad market application prospects. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the lubricating oil filter element of this utility model;

[0024] Figure 2 This is a cross-sectional view of the filter layer assembly of this utility model, showing a schematic diagram of its structural layout.

[0025] Figure 3 This is a schematic diagram of the oil flow direction of the filter layer assembly of this utility model;

[0026] Figure 4 This is a three-dimensional structural diagram of the lubricating oil filter element of this utility model.

[0027] In the attached diagram, 1 is the outer end cap; 2 is the inner end cap; 3 is the frame; 4 is the filter layer assembly; 5 is the sealing element; 6 is the metal mesh layer; 7 is the non-woven fabric layer; and 8 is the glass fiber paper layer. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0029] Reference Figures 1 to 4 The image shows an oil filter element for an aircraft lubrication system. The filter element includes: an outer end cap 1 and an inner end cap 2 arranged coaxially; a cylindrical frame 3 extending axially between the outer end cap 1 and the inner end cap 2; a filter layer assembly 4 sleeved on the outer periphery of the frame 3 and composed of multiple layers of filter media stacked radially; and a sealing element 5 located between the outer end cap 1 and the inner end cap 2 for sealing both ends of the filter layer assembly 4. The inner circumferential surface of the filter layer assembly 4 is attached to the outer circumferential surface of the frame 3, and both ends of the filter layer assembly 4 are clamped and fixed between the axial end faces of the outer end cap 1 and the inner end cap 2, forming a unidirectional flow filter channel from the outside to the inside radially.

[0030] Further explanation is that the outer end cap 1 is an aluminum alloy annular plate with an oil passage hole in the center. During assembly, it is located at the oil outlet end of the filter element and is coaxial with the central axis of the filter element. The inner end face of the outer end cap 1 (facing the inside of the filter element) has an annular sealing groove for embedding the sealing element 5; its outer edge may have a flange with rivet holes evenly distributed around its circumference, which are riveted to the inner end cap 2 to form an integral unit, thereby forming an axial clamping of the frame 3 and the filter layer assembly 4. The outer end cap 1 seals one end of the filter element, providing an oil outlet channel; the flange and rivets achieve integral assembly; the flange also serves as a protective shell to prevent mechanical damage to the filter layer.

[0031] The inner end cap 2 and the outer end cap 1 are both made of aluminum alloy annular flat plates, but the diameter of the central oil passage hole is slightly larger, serving as the oil inlet end. It is arranged face-to-face and coaxially with the outer end cap 1; similarly, a sealing groove is provided on the inner end face to embed the sealing element 5; the outer edge flange corresponds to the flange of the outer end cap 1, and is locked with the same set of rivets to form a rigid frame. It is used to seal the other end of the filter element, providing an oil inlet channel; it works in conjunction with the outer end cap 1 to complete the fixing and sealing of the filter element assembly; the flange also serves as the outer shell and facilitates the overall installation and positioning of the machine.

[0032] The cylindrical frame 3 is made of stainless steel perforated cylinder. The frame is designed with 1036 evenly distributed perforations with a diameter of 1.5mm. The material is high-strength and corrosion-resistant H32 aluminum alloy, which greatly increases the strength of the filter element and significantly improves its adaptability under high flow rates of lubricating oil. At the same time, its low density also meets the requirements of lightweight design for aerospace components. Its length is equal to the net distance between the inner end faces of the outer end cap 1 and the inner end cap 2. The cylindrical frame 3 has radial flanges on the outer periphery of both ends. The flanges are respectively embedded in the central holes of the outer end cap 1 and the inner end cap 2 to form a clearance fit and achieve radial positioning; at the same time, they are axially pressed by the two end caps to achieve axial fixation. It is used to support the filter layer assembly 4 and prevent the filter layer from collapsing under oil pressure; the perforated structure ensures uniform oil flow and reduces pressure drop; the flange structure simplifies assembly, eliminates the need for welding, and can be repeatedly disassembled and reassembled.

[0033] The filter layer assembly 4 consists of a metal mesh layer 6, a non-woven fabric layer 7, and a fiberglass paper layer 8 stacked sequentially from the outside in. These three layers are bonded together with dotted hot melt adhesive to form a single cylindrical structure, which is then fitted over the outer circumference of the frame 3. The inner circumferential surface is in contact with the outer circumferential surface of the frame 3; both end faces are axially pressed together by the outer end cap 1, the inner end cap 2, and the sealing element 5 to achieve end sealing; the radial direction is supported by the frame 3 without additional mechanical fixation. The metal mesh layer 6 pre-filters large particles and protects the inner layer; the non-woven fabric layer 7 intercepts medium-sized impurities; and the fiberglass paper layer 8 completes fine filtration. The three layers work synergistically to significantly improve dirt holding capacity and filtration accuracy; the radial unidirectional flow from the outside in prevents secondary contamination.

[0034] The sealing element 5 uses oil-resistant fluororubber O-rings, which are installed in the annular sealing grooves of the outer end cap 1 and the inner end cap 2, respectively. The O-rings undergo elastic deformation under the axial compression of the end caps and the end faces of the filter layer assembly 4, forming an end face seal; at the same time, they fill the gap between the flange of the skeleton 3 and the center hole of the end cap, playing an auxiliary radial sealing role. This is used to prevent unfiltered oil from bypassing the end face of the filter layer; to ensure the overall sealing reliability of the filter element; and to allow the end caps to maintain their sealing performance after multiple disassemblies and reassemblies.

[0035] In some specific embodiments, the sealing element 5 is an O-ring, which is embedded in the annular sealing grooves opened on the side of the outer end cap 1 and the inner end cap 2 facing the filter layer assembly 4, and simultaneously presses the two end faces of the filter layer assembly 4.

[0036] In some specific embodiments, the skeleton 3 is a perforated metal cylinder with holes evenly distributed on the cylinder wall to support the filter layer assembly 4 and maintain oil flow.

[0037] In some specific embodiments, the filter layer assembly 4 includes, from the outside to the inside, a metal mesh layer 6, the outer peripheral surface of which is radially aligned with the inner peripheral surface of the outer end cap 1; a non-woven fabric layer 7, the inner peripheral surface of which is attached to the inner peripheral surface of the metal mesh layer 6; and a glass fiber paper layer 8, the inner peripheral surface of which is attached to the inner peripheral surface of the non-woven fabric layer 7 and to the outer peripheral surface of the skeleton 3.

[0038] In some specific embodiments, the metal mesh layer 6, the non-woven fabric layer 7, and the fiberglass paper layer 8 are bonded together with hot melt adhesive in a dotted manner to form a whole before being fitted onto the skeleton 3.

[0039] In some specific embodiments, the outer end cap 1 and the inner end cap 2 are both aluminum alloy annular plates, which are coaxially arranged opposite each other, and each has a flange on its radial outer edge to cover the outer periphery of the end of the filter layer assembly 4.

[0040] In some specific embodiments, the outer end cap 1 and the inner end cap 2 are two sets; they are respectively set at both ends of the frame 3 and the filter layer assembly 4, and the frame 3 and the filter layer assembly 4 are axially clamped.

[0041] In some specific embodiments, the two ends of the skeleton 3 are respectively provided with radial flanges, which are embedded in the central holes of the outer end cover 1 and the inner end cover 2 to form a positioning fit.

[0042] In some specific embodiments, the metal mesh is made of stainless steel; the non-woven fabric is made of polyester non-woven fabric; and the O-ring is made of rubber.

[0043] The working principle of this utility model oil filter element:

[0044] fluid path

[0045] Under the pressure difference of the oil supply pump, the oil in the aircraft lubrication system enters the internal cavity of the filter element from the central through hole of the inner end cover 2 along the axial direction. Then the oil is forced to change its flow direction and passes through the metal mesh layer 6 → non-woven fabric layer 7 → glass fiber paper layer 8 in the radial direction of the filter layer assembly 4 from the outside to the inside. Finally, it flows into the inner cavity of the frame through the holes of the perforated frame 3 and then flows out from the central hole of the outer end cover 1, completing unidirectional filtration.

[0046] Staged filtration mechanism

[0047] The metal mesh layer 6 forms a coarse filter screen, which uses larger mesh openings to trap metal chips and sealing debris ≥150μm, reducing the instantaneous load on subsequent layers;

[0048] The non-woven fabric layer 7 utilizes the three-dimensional porous structure of fibers for deep filtration, capturing particles with a uniform particle size of 20–150 μm, while simultaneously dispersing oil flow and buffering impact.

[0049] The glass fiber paper layer 8 completes fine filtration through a dense surface layer interwoven with fine glass fibers, removing fine contaminants ≥3μm, so that the cleanliness of the outlet oil reaches the aviation standard ISO 440615 / 12 / 10 level.

[0050] Mechanism and Support Mechanism

[0051] The perforated frame 3 provides radial rigid support for the overall filter layer; its uniform holes ensure uniform oil distribution and prevent local high-speed scouring that could damage the filter layer; the radial flanges at both ends of the frame are embedded in the center hole of the end cap to form an integrated "positioning-clamping" structure, ensuring no collapse or displacement under high vibration and high pressure differential of 2MPa.

[0052] Sealing mechanism

[0053] Under the axial clamping force of the rivets, the O-rings 5 ​​at both ends are compressed by 18%–22%, forming the main end face seal; at the same time, the O-rings fill the gap between the skeleton flange and the center hole of the end cap, forming a secondary radial seal, completely blocking the bypass of unfiltered oil.

[0054] Differential Pressure and Lifespan Management

[0055] As contaminants deposit on the outer surface of the filter layer, the pressure difference across the filter element gradually increases. When the pressure difference reaches the system's set upper limit, such as 0.25 MPa, the sensor triggers a replacement alarm. Due to the high dirt-holding capacity of the three-layer composite structure, the filter element has a lifespan of ≥500 flight hours under typical aviation lubrication conditions.

[0056] The working method of this utility model:

[0057] 1. Installation:

[0058] Connecting to the external system: Connect the threaded interfaces on the outer and inner end caps of the filter element to the oil inlet and outlet pipes of the aircraft lubrication system. The thread of the outer end cap engages with the internal thread at one end of the frame, and the thread of the inner end cap engages with the internal thread at the other end of the frame. The connection is made by screwing the threads together and sealing with an O-ring to ensure a tight seal at the connection.

[0059] Check for leaks: After installation, check the leaks at all joints to ensure there is no lubricant leakage. This can be done by applying lubricant under pressure and observing for any leaks at the joints.

[0060] 2. Operation:

[0061] Starting the lubrication system: When the aircraft lubrication system is started, the lubricating oil enters the filter element through the oil inlet of the outer end cover, passes through multiple stages of filtration in the filter layer assembly, and finally flows out from the oil outlet of the inner end cover to enter the lubrication system of the aircraft engine or other critical components.

[0062] Monitor operating status: During operation, monitor parameters such as pressure drop and temperature of the filter element to ensure it operates within its normal operating range. If an abnormal increase in pressure drop or abnormal temperature change is detected, promptly check whether the filter element is clogged or damaged.

[0063] 3. Maintenance and Replacement:

[0064] Regular inspection: According to the aircraft lubrication system maintenance manual, regularly check the condition of the filter element, including visual inspection and pressure drop measurement. If obvious damage is found on the surface of the filter element or the pressure drop exceeds the specified value, the filter element should be replaced in time.

[0065] Quick Replacement: Due to the modular design of the filter element, replacement only requires disassembling the threaded connection between the outer and inner end caps, removing the old filter element, installing the new filter element, and reconnecting. The entire replacement process is simple and quick, reducing maintenance time and downtime.

[0066] In summary, the beneficial effects of this utility model are as follows:

[0067] Multi-stage filtration: Metal mesh layer 6 pre-filters large particles, non-woven fabric layer 7 intercepts medium impurities, and glass fiber paper layer 8 finely filters tiny particles, increasing dirt holding capacity by more than 30%.

[0068] Low pressure drop: The uniform perforated support of the frame 3 reduces filter layer deformation and lowers pressure drop by 15%–20%.

[0069] Maintainability: The outer end cover 1 and the inner end cover 2 are fastened together by rivets. The filter layer assembly can be replaced by removing the rivets, reducing maintenance time by 50%.

[0070] High sealing performance: The O-ring is embedded in the end cap sealing groove, axially pressing the sealing surface to prevent bypass leakage.

[0071] Lightweight: The aluminum alloy end cap and perforated frame structure reduce the weight by 25% compared to traditional welded steel parts, meeting the weight reduction requirements of aviation.

[0072] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An oil filter cartridge for use in an aircraft lubrication system, characterized in that, The filter element includes: The outer end cap (1) and the inner end cap (2) are arranged coaxially. A cylindrical skeleton (3) extending axially between the outer end cap (1) and the inner end cap (2); A filter layer assembly (4) is fitted around the outer periphery of the skeleton (3) and is composed of multiple layers of filter media stacked radially in sequence. And a sealing element (5) located between the outer end cap (1) and the inner end cap (2) for sealing both ends of the filter layer assembly (4); The inner circumferential surface of the filter layer assembly (4) is attached to the outer circumferential surface of the skeleton (3), and the two ends of the filter layer assembly (4) are respectively clamped and fixed between the axial end faces of the outer end cover (1) and the inner end cover (2) to form a unidirectional filter channel that flows radially from the outside to the inside. The sealing element (5) is an O-ring, which is embedded in the annular sealing grooves opened on the side of the outer end cap (1) and the inner end cap (2) facing the filter layer assembly (4), and simultaneously presses the two end faces of the filter layer assembly (4). The skeleton (3) is a metal perforated cylinder with holes evenly distributed on the cylinder wall, which is used to support the filter layer assembly (4) and maintain the flow of oil. The filter layer assembly (4) comprises, from the outside in, the following components: The outer peripheral surface of the metal mesh layer (6) is radially aligned with the inner peripheral surface of the outer end cap (1); The non-woven fabric layer (7) has its inner circumferential surface attached to the inner circumferential surface of the metal mesh layer (6); The inner circumferential surface of the fiberglass paper layer (8) is attached to the inner circumferential surface of the nonwoven fabric layer (7) and to the outer circumferential surface of the skeleton (3); The metal mesh layer (6), non-woven fabric layer (7) and glass fiber paper layer (8) are bonded together with hot melt adhesive to form a whole and then fitted onto the skeleton (3). Both the outer end cap (1) and the inner end cap (2) are aluminum alloy annular plates, which are coaxially arranged opposite each other, and have flanges on their respective radial outer edges to cover the outer periphery of the end of the filter layer assembly (4); The outer end cap (1) and the inner end cap (2) are two sets; respectively set at both ends of the frame (3) and the filter layer assembly (4), axially clamping the frame (3) and the filter layer assembly (4); The skeleton (3) has radial flanges at both ends, and the flanges are embedded in the central holes of the outer end cap (1) and the inner end cap (2) to form a positioning fit; The metal mesh layer (6) is made of stainless steel; the non-woven fabric layer (7) is made of polyester non-woven fabric; and the sealing element (5) is made of rubber.

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