An oil sump for an in-line piston engine, an engine and an aircraft thereof

Abstract

The utility model relates to the technical field of engine oil sump, especially an oil sump of in-line piston engine, an engine and an aircraft, the oil sump is installed in the lower part of engine crankcase body assembly, the oil sump is formed as a basin -like structure with the basically level inner bottom surface, the inner bottom surface of the oil sump is concave downward and forms the oil storage groove that the structure is further outward protruding relative to the outer bottom surface of the oil sump, the upper part inboard of the oil sump is provided with the oil return interface, the bottom of the oil storage groove is provided with the through oil drain hole, the oil drain bolt is sealed in the oil drain hole, the wide edge sealing pad is installed on the sealing edge contact surface of the oil sump and engine crankcase body assembly connection, and the width of wide edge sealing pad is greater than the width of sealing edge contact, the utility model simplifies the oil sump structure, so that can adapt to the large inclination of aircraft ±45 DEG movement, greatly reduces the oil leakage risk simultaneously, and reduces the maintenance cost.

Description

Technical Field

[0001] This utility model relates to the field of engine oil pan technology, specifically to an oil pan for an inline piston engine, the engine, and its aircraft. Background Technology

[0002] In recent years, drones using 4-cylinder piston engines directly driving propellers, typical of small manned aircraft, have gradually entered the market. However, the vast majority of these engines are horizontally opposed, and the application of drones equipped with inline 4-cylinder piston engines remains relatively limited. In the fields of large industrial drones and small manned aircraft, the main technical challenge facing inline 4-cylinder piston engines lies in their large dimensions, including height and length, which directly affects the engine's compatibility with the aircraft. Although improved small inline piston engines exist, the design of their oil pan, the oil storage component, has significant flaws: First, traditional oil pans use ordinary gaskets for sealing, which are prone to seal failure and oil leakage during long-term engine operation; second, the drain plug uses ordinary threaded connections, which are prone to loosening under high-frequency vibration conditions in aircraft, not only increasing the risk of oil leakage but also increasing maintenance frequency; third, the oil return path design is unreasonable, and direct oil impact on the reservoir can cause oil splashing, affecting the stability of the lubrication system; furthermore, the existing oil pan structure lacks sufficient strength and is prone to deformation during engine operation, further exacerbating the seal failure problem. These technical deficiencies severely restrict the reliability of inline piston engines in the aviation field. To address these issues, existing technologies urgently need improvement. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an oil pan for an inline piston engine, the engine and its aircraft.

[0004] To achieve the above objectives, this utility model provides the following technical solution: an oil pan for an inline piston engine, wherein the oil pan is installed on the lower part of the engine crankcase assembly, the oil pan is formed as a basin-shaped structure with a basically horizontal inner bottom surface, the inner bottom surface of the oil pan is recessed downward to form an oil reservoir that protrudes further outward relative to the outer bottom surface of the oil pan, and an oil return interface is provided on the upper inner side of the oil pan; a through-hole is provided at the bottom of the oil reservoir, and an oil drain bolt is sealed in the oil drain hole; a wide-edge sealing gasket is installed on the sealing edge contact surface where the oil pan connects to the engine crankcase assembly, and the width of the wide-edge sealing gasket is greater than the width of the sealing edge contact.

[0005] The upper end of the oil return interface is connected to the oil return device and its engine oil return pipeline system in the engine crankcase assembly, and the lower end of the oil return interface is connected to the stepped surface inside the oil pan that is higher than the oil reservoir. The oil return interface adopts a C-shaped side wall opening design, and the side wall opening of the oil return interface is connected to the oil reservoir through the stepped surface of the oil pan.

[0006] The head of the drain bolt is in tight contact with the outer bottom surface of the oil reservoir. A limit protrusion is provided on the outer bottom surface of the oil reservoir corresponding to the side of the drain bolt head. A set hole is provided on the limit protrusion facing the head of the drain bolt. An anti-loosening limit hole is provided on the head of the drain bolt. A limit pin or anti-loosening safety wire is provided through the set hole and the anti-loosening limit hole.

[0007] In some embodiments, the outer edge of the wide-edge sealing gasket is flush with the outer edge of the sealing edge contact surface.

[0008] In some embodiments, the oil reservoir is located at the center of the oil pan, and there is a smooth transition between the outer bottom surface of the oil pan and the outer side wall of the oil reservoir. The vertical space between the horizontal plane where the outer bottom surface of the oil reservoir is located and the outer bottom surface of the oil pan constitutes the exhaust pipe installation space. The exhaust pipe of the engine crankcase assembly is installed in the exhaust pipe installation space outside the oil pan.

[0009] In some embodiments, an oil guide plate is vertically arranged inside the oil pan, above the oil storage tank, corresponding to the oil return interface, and one end of the oil guide plate is connected to the side opening of the oil return interface near the oil storage tank.

[0010] In some embodiments, the central hole connecting the stepped surface inside the oil pan, which is higher than the oil reservoir, and the return oil interface is designed as a recessed hole, and there is a smooth transition between the recessed hole and the stepped surface inside the oil pan, which is higher than the oil reservoir.

[0011] In some embodiments, the bottom of the oil reservoir is provided with a C-shaped drain ring integrated with the oil pan at the drain hole. The side notch of the C-shaped drain ring is connected to the bottom surface of the oil reservoir. The inner wall of the C-shaped drain ring is flush with the inner wall of the drain hole. The inner wall of the C-shaped drain ring and the inner wall of the drain hole are provided with fixing threads that match the drain bolt.

[0012] In some embodiments, the head of the drain bolt is an external hexagonal bolt head or an internal hexagonal bolt head, and each sidewall plane of the drain bolt head is provided with a through anti-loosening limiting hole.

[0013] In some embodiments, a plurality of reinforcing ribs are provided on the smooth connection surface between the upper inner side of the oil pan and the oil storage tank, and reinforcing ribs are provided between the inner bottom surface of the oil storage tank and the side wall of the oil storage tank.

[0014] In some embodiments, the upper part of the oil pan is evenly provided with a plurality of mounting bolts connecting the oil pan and the bottom of the engine crankcase assembly. Each mounting bolt has a plurality of anti-loosening safety holes on its head, and all the mounting bolts are sequentially arranged through the corresponding anti-loosening safety holes.

[0015] To achieve the above objectives, the present invention also provides the following technical solution: an engine having an oil pan as described above.

[0016] To achieve the above objectives, the present invention also provides the following technical solution: an aircraft equipped with the aforementioned engine.

[0017] Compared with the prior art, the beneficial effects of this utility model are: by using a wide-edge sealing gasket, optimizing the oil reservoir structure and exhaust pipe channel design, it solves the leakage problem caused by insufficient sealing performance and complex structure of the existing oil pan. It has the advantages of improving sealing performance, reducing oil consumption, enhancing structural stability and adaptability. The introduction of a wide-edge oil pan sealing gasket can adapt to the large tilt angle ±45° movement of the aircraft.

[0018] By adding a drain bolt anti-loosening fixing support point on the oil pan, the drain bolt is prevented from loosening during engine operation, effectively solving the leakage problem caused by the loosening of traditional drain bolts due to vibration. At the same time, the oil reservoir design is optimized to reduce waste oil residue, which has the advantages of improving maintenance safety and reliability.

[0019] The oil pan's stepped surface and C-shaped opening allow for orderly oil return, while the oil reservoir and guide components suppress splashing. This design effectively reduces oil impact and splashing, lowers noise and vibration, prevents oil oxidation and foaming, and improves the efficiency and lifespan of the lubrication system.

[0020] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the oil pan and wide-edge sealing gasket of this utility model.

[0023] Figure 3 This is a top view of the present invention;

[0024] Figure 4 This is a schematic diagram of the lower structure of the oil pan of this utility model;

[0025] Figure 5 This is a front view of the present invention;

[0026] Figure 6 This is a schematic diagram showing the fit between the oil pan and the exhaust pipe.

[0027] In the diagram: 1. Oil pan; 2. Oil reservoir; 3. Sealing edge contact surface; 4. Wide edge sealing gasket; 5. Exhaust pipe channel; 6. Drain hole; 7. Reinforcing rib plate one; 8. Reinforcing rib plate two; 9. Assembly bolt; 10. Drain bolt; 11. Bolt head; 12. Limiting protrusion; 13. Set through hole; 14. Anti-loosening limiting through hole; 15. C-shaped drain ring; 16. Oil return interface; 17. Stepped surface; 18. Side wall opening; 19. Oil guide plate; 20. Recessed hole. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] In existing technologies, inline 4-cylinder piston engines present challenges in terms of aircraft installation compatibility due to their large size. The complex oil pan structure of current models is prone to oil leaks, and ordinary drain plugs are susceptible to loosening under high-frequency vibration, requiring frequent maintenance. Direct oil return to the reservoir can also cause impact splashing. These issues limit the application of inline engines in industrial drones and small manned aircraft.

[0030] To address these issues, optimizing the oil pan structure to reduce leakage risk is crucial. Considering the impact of high-frequency vibration on bolted connections, a reliable anti-loosening structure needs to be designed. Simultaneously, the oil return path needs to be redesigned to reduce fluid shock. Based on these considerations, a new solution is formed by constructing a split oil storage structure with a limiting mechanism and improving the oil return path design.

[0031] Therefore, this application proposes an oil pan for an inline piston engine, wherein the inner bottom surface is a horizontal basin-shaped structure and is recessed downward to form an oil reservoir 2, the outer bottom surface of the oil reservoir 2 is convex and an oil drain hole 6 is opened at the bottom, and an oil drain bolt is installed in the oil drain hole 6. The upper inner side of the oil pan 1 is provided with a C-shaped side wall opening 18 for an oil return interface 16, and a wide-edge sealing gasket 4 is installed on the sealing edge.

[0032] The oil reservoir 2 refers to an independent oil storage space formed by a recess in the inner bottom surface. It can be manufactured using a stamping process, and the oil storage capacity is controlled by the depth of the recess. This structure separates the oil storage area from the main body of the oil pan 1, reducing the impact of liquid sloshing on the seal.

[0033] The positioning element 12 on the outer bottom surface of the oil reservoir 2 is used to fix the drain bolt 10. Typically, a positioning pin or anti-loosening safety wire passes through the through hole 13 of the positioning element and the anti-loosening limiting through hole 14 of the drain bolt. This mechanical limiting method prevents the drain bolt from rotating and loosening. This design improves the reliability of anti-loosening by replacing traditional thread friction with physical constraints.

[0034] The C-shaped sidewall opening 18 refers to the cross-sectional shape of the oil return interface 16, which can be formed by welding a bent steel plate. The opening direction forms a guide channel with the sidewall of the oil storage tank 2. This structure allows the returning oil to flow slowly into the oil storage tank 2 along the sidewall, avoiding direct impact on the liquid surface.

[0035] Specifically, the basin-shaped oil pan 1 maintains a stable oil level through its horizontal inner bottom surface, while the oil reservoir 2 protrudes from its outer bottom surface, providing space for the installation of a limiting pin or a locking wire. After the drain bolt 10 is tightened, a limiting pin or a locking wire is inserted between its side wall locking through-hole 14 and the locking through-hole 13 on the outer bottom surface of the oil reservoir 2 to form a rigid constraint. The C-shaped opening of the return oil port 16 connects to the stepped surface 17 of the oil pan 1, allowing oil to flow along the side wall into the non-central area of ​​the oil reservoir 2. The wide-edge sealing gasket 4 covers the entire sealing edge contact surface 3, compensating for unevenness of the mounting surface.

[0036] Compared to existing technologies, the traditional integrated design of the oil reservoir 2 and the oil pan 1 is prone to sealing failure, while the separate structure of this solution reduces the pressure on the sealing surface. Ordinary drain bolts 10 rely on thread preload to prevent loosening; this solution uses a limit pin or anti-loosening safety wire for mechanical locking. Existing oil return paths involve vertical descent; this solution uses a C-shaped opening for lateral flow guidance to mitigate impact.

[0037] The above technical solutions effectively prevent bolt loosening and leakage caused by high-frequency vibration, reduce splashing caused by oil backflow impact, and at the same time, the split oil storage structure reduces the load on the sealing surface and improves the overall sealing reliability of the oil pan 1.

[0038] This application further proposes that the outer edge of the wide-edge sealing gasket 4 is flush with the outer edge of the sealing edge contact surface 3.

[0039] The wide-edge sealing gasket 4 is a sealing element installed at the connection between the oil pan 1 and the engine crankcase assembly. It can be molded from rubber or composite materials, and its width is greater than the width of the sealing edge contact surface 3, forming a reliable sealing barrier between the connecting surfaces. The sealing edge contact surface 3 is the mounting surface where the oil pan 1 and the engine crankcase assembly meet. It can be machined to form a flat contact area, serving to support the sealing gasket and transmit assembly pressure. "Flush" means that the outer edge of the wide-edge sealing gasket 4 and the outer edge of the sealing edge contact surface 3 are on the same plane. This can be achieved through precise installation positioning or matching the pre-formed dimensions of the sealing gasket, preventing the sealing gasket from shifting or folding during installation.

[0040] Specifically, during installation, the outer edge of the wide-edge sealing gasket 4 is flush with the outer edge of the sealing edge contact surface 3, preventing localized deformation due to edge misalignment during assembly. When the oil pan 1 is bolted to the engine crankcase assembly, the entire width of the sealing gasket is evenly compressed, avoiding uneven pressure distribution caused by edge misalignment. This design ensures the outer edge of the sealing gasket does not extend beyond the contact surface, eliminating the risk of oil leakage due to localized gasket suspension or uneven stress.

[0041] Compared to existing technologies, traditional oil pan gaskets typically employ a design where the width is less than or equal to the contact surface. During assembly, installation errors can easily lead to gasket edge misalignment, resulting in localized seal failure. This solution, however, utilizes a flush-edge design to ensure complete gasket coverage within the contact surface, preventing performance degradation due to edge misalignment or gaps. Under high-frequency engine vibration conditions, this structure maintains the stability of the sealing interface, reducing gasket creep or loosening caused by vibration. Furthermore, the wide-edge oil pan gasket can accommodate large tilt angles (±45°) of the aircraft.

[0042] Through the above technical solution, this application effectively solves the problem of sealing failure caused by installation misalignment of the oil edge gasket, and reduces the risk of oil leakage at the connection between the oil pan 1 and the engine crankcase assembly. This design improves the overall reliability of the sealing interface by optimizing the edge alignment between the gasket and the contact surface, reducing maintenance needs caused by poor sealing, and is suitable for inline piston engine applications with high requirements for vibration tolerance and sealing stability.

[0043] This application further proposes an oil pan 1 for an inline piston engine, wherein the outer bottom surface of the oil pan 1 smoothly transitions to the outer side wall of the oil reservoir 2, and the vertical space between the horizontal plane where the outer bottom surface of the oil reservoir 2 is located and the outer bottom surface of the oil pan 1 constitutes an exhaust pipe installation space, and the exhaust pipe of the engine crankcase assembly is installed in the exhaust pipe installation space outside the oil pan 1.

[0044] The smooth transition refers to the formation of a continuous curvature or gradually changing slope between the outer bottom surface and the outer wall of the oil reservoir 2. This can be achieved using a circular arc transition or a conical slope structure, thereby reducing stress concentration and improving structural strength. The exhaust pipe installation space refers to the cavity area formed by the vertical distance between the outer bottom surface of the oil reservoir 2 and the outer bottom surface of the oil pan 1. This space can be controlled by adjusting the depth of the recess in the oil reservoir 2 and is used to accommodate the installation brackets and fixing components of the exhaust pipe.

[0045] Specifically, a naturally extending structural space is formed in the smooth transition area between the outer bottom surface of the oil pan 1 and the outer wall of the oil reservoir 2. This space is achieved through the vertical height difference between the outer bottom surface of the oil reservoir 2 and the outer bottom surface of the oil pan 1. The exhaust pipe installation position is integrated into the outer contour of the oil pan 1, eliminating the need to occupy the installation area under the engine crankcase assembly. In this design, the recessed depth of the oil reservoir 2 matches the overall height of the oil pan 1, allowing the exhaust pipe mounting bracket to be directly fixed to the transition area between the outer bottom surface of the oil pan 1 and the outer bottom surface of the oil reservoir 2.

[0046] Compared to existing technologies, the traditional oil pan 1 design does not consider the installation space for the exhaust pipe, resulting in the need to reserve additional area at the bottom of the engine crankcase assembly for the exhaust system, thus increasing the overall height. This solution integrates the installation space for the exhaust pipe within the contour of the oil pan 1 itself through a structurally integrated design, while utilizing the vertical space formed by the recess of the oil reservoir 2 to achieve a compact layout of the exhaust pipe.

[0047] Through the above technical solution, this application solves the installation compatibility problem caused by the excessively large size of inline engines. By optimizing the structure of the oil pan 1, spatial integration of the engine crankcase assembly and exhaust pipe is achieved, reducing the height requirements of the engine assembly and avoiding the structural interference risk caused by external exhaust pipe mounting brackets. In addition, the smooth transition design reduces the processing difficulty of the oil pan 1 during manufacturing and improves the fatigue resistance of the housing under vibration environment.

[0048] This application further proposes that the oil storage tank 2 be located at the center of the oil pan 1.

[0049] The oil reservoir 2 being located in the center of the oil pan 1 means that the geometric center of the oil reservoir 2 coincides with the geometric center of the inner bottom surface of the oil pan 1. This can be achieved through a symmetrical structural design or by adjusting the shape of the inner bottom surface of the oil pan 1. This design, by centrally positioning the oil reservoir 2, ensures a symmetrical flow path for the engine oil within the oil pan 1, reducing uneven oil distribution caused by the eccentricity of the oil reservoir 2.

[0050] Specifically, the inner bottom surface of the oil pan 1 has a horizontal basin-shaped structure, and the oil reservoir 2 is formed by a downward indentation in the central area of ​​the inner bottom surface. The outer bottom surface of the oil reservoir 2 protrudes further outward relative to the outer bottom surface of the oil pan 1. During engine operation, after the engine oil enters the oil pan 1 through the return port 16, the oil reservoir 2 is located in the center, and the oil flows evenly into the oil reservoir 2 along the stepped surface 17, avoiding the accumulation of oil on one side due to the offset of the oil reservoir 2, thereby reducing the amplitude of liquid level sloshing in the oil reservoir 2. In addition, the central layout makes the drain hole 6 and the limiting protrusion 12 on the outer bottom surface of the oil reservoir 2 form symmetrical support, reducing the risk of loosening of the drain bolt 10 due to vibration.

[0051] Compared to existing technologies, the oil reservoir 2 in existing technologies is usually located on the side or asymmetrically in the oil pan 1, which causes eddies or splashes to form in the oil reservoir 2 when the oil flows back, increasing the risk of leakage from the gasket. In contrast, this application achieves more stable oil flow through a central layout, and the exhaust pipe installation space between the outer bottom surface of the oil reservoir 2 and the outer bottom surface of the oil pan 1 is symmetrically distributed, facilitating the external integration of the engine exhaust pipe.

[0052] Through the above technical solutions, this application effectively reduces the probability of oil leakage in the oil pan 1 under vibration conditions, improves the stability of the liquid level inside the oil reservoir 2, and optimizes the installation space adaptability of external engine components through symmetrical layout.

[0053] This application further proposes an oil pan 1 for an inline piston engine. Inside the oil pan 1, a stepped surface 17 higher than the oil reservoir 2 is vertically provided with an oil guide plate 19 corresponding to the oil return port 16. One end of the oil guide plate 19 is connected to the side opening 18 of the oil return port 16 near the oil reservoir 2.

[0054] The oil guide plate 19 is a thin plate structure vertically installed between the stepped surface 17 and the oil return port 16. It can be made of welded or stamped metal sheet. Its function is to guide the oil output from the oil return port 16 along the plate surface to the oil reservoir 2, preventing the oil from directly impacting the oil surface of the reservoir 2. The side wall opening 18 is a C-shaped channel at the connection between the side wall of the oil return port 16 and the stepped surface 17 of the oil pan 1. Its function is to redirect the oil flow path through the lateral opening. The opening edge connection refers to the fixed connection between the oil guide plate 19 and the opening edge of the oil return port 16. This connection can be made by welding or integral injection molding. Its function is to ensure the oil guide plate 19 maintains a stable posture under vibration through a rigid connection.

[0055] Specifically, the oil guide plate 19 is vertically positioned above the stepped surface 17, with its bottom end fixedly connected to the opening edge of the oil return port 16. When engine oil returns from the engine oil return device and its engine oil return pipeline system through the oil return port 16, the oil flows through the C-shaped side wall opening 18 and directly contacts the surface of the oil guide plate 19. Guided by the oil guide plate 19, the oil flows smoothly along the side of the oil guide plate 19 into the oil reservoir 2.

[0056] Compared to existing technologies, traditional oil pans 1 lack an oil guide plate 19 structure, causing engine oil to fall vertically into the oil reservoir 2 directly through the return port 16, resulting in violent fluctuations in the oil surface and oil splashing. This solution, through the directional guiding effect of the oil guide plate 19, transforms the vertical falling impact into a smooth flow along the plate surface, effectively eliminating surface disturbance. Furthermore, the rigid connection between the oil guide plate 19 and the opening edge can withstand high-frequency engine vibrations, preventing flow guidance failure caused by structural loosening.

[0057] Through the above technical solution, this application solves the problem of splashing caused by impact on the oil reservoir 2 during oil return, and improves the stability of the oil circulation system. The directional guiding effect of the oil guide plate 19 reduces the amplitude of liquid level fluctuations, reduces foaming caused by oil contact with air, and ensures the reliability of the structure under vibration environment through mechanical fixing, thus reducing maintenance requirements.

[0058] This application further proposes that the center hole at the connection between the stepped surface 17 inside the oil pan 1, which is higher than the oil storage tank 2, and the return oil interface 16 is designed as a recessed hole 20, and the recessed hole 20 and the stepped surface 17 inside the oil pan 1, which is higher than the oil storage tank 2, are smoothly transitioned.

[0059] The recessed hole 20 refers to the recessed structure formed at the connection center hole of the oil return interface 16. This can be achieved through stamping or casting processes. The depth of the recess can be one-fifth to one-third of the vertical height of the stepped surface 17 of the oil pan 1. This structure slows down the flow rate of engine oil as it enters the oil reservoir 2 from the oil return interface 16. The smooth transition refers to the use of an arc-shaped curved surface at the connection between the recessed hole 20 and the stepped surface 17. This can be achieved through mold forming processes. This structure avoids right angles or abrupt changes in the oil flow path, thereby reducing flow resistance.

[0060] Specifically, with the oil pan 1 installed, the oil received by the return port 16 flows into the recessed hole 20 area through the central hole. The recessed hole 20 guides the oil smoothly into the oil reservoir 2 along the curved surface through its concave structure, avoiding direct impact on the oil surface of the reservoir 2. The smooth transition between the stepped surface 17 and the recessed hole 20 allows the oil to form a continuous flow path under gravity, reducing the probability of turbulence during the flow process.

[0061] Compared with existing technologies, the traditional oil pan 1 return port 16 is directly connected to the oil reservoir 2, and the oil enters the oil reservoir 2 in the form of free fall, resulting in oil splashing. However, this solution uses the buffer structure formed by the concave hole 20 and the smooth transition to gradually consume the kinetic energy of the oil during the flow process, which significantly reduces the oil splashing phenomenon in the oil reservoir 2.

[0062] Through the above technical solution, this application solves the problem of oil splashing caused by oil return impact in the oil pan 1 of an inline engine, ensures a smooth oil flow path, reduces the probability of oil contact with air, thereby reducing oil oxidation and improving the stability of the lubrication system.

[0063] This application further proposes that a C-shaped drain ring 15, which is integral with the oil pan 1, is provided at the bottom of the oil storage tank 2 at the drain hole 6. The side notch of the C-shaped drain ring 15 is connected to the bottom surface of the oil storage tank 2. The inner wall of the C-shaped drain ring 15 is flush with the inner wall of the drain hole 6. The inner wall of the C-shaped drain ring 15 and the inner wall of the drain hole 6 are provided with fixing threads that match the drain bolt 10.

[0064] The C-shaped drain ring 15 is an annular structure integrally formed with the oil pan 1 and having a C-shaped cross-section. It can be achieved through casting or stamping processes. Its side notch design forms a continuous support structure with the inner bottom surface of the oil reservoir 2. The flush surface setting means that the inner wall of the C-shaped drain ring 15 is on the same plane as the inner wall of the drain hole 6. This can be achieved through mold processing to ensure accuracy, thus avoiding gaps during threaded connection. The fixing thread refers to the internal thread structure that matches the external thread of the drain bolt 10. It can be machined using standard thread specifications to achieve the tightening and fixing of the drain bolt 10.

[0065] Specifically, the C-shaped drain ring 15 is directly connected to the inner bottom surface of the oil reservoir 2 through a side notch, forming an integrated structure to enhance overall strength. During maintenance, it ensures complete drainage of the oil in the reservoir 2, preventing residual oil accumulation. The inner wall of the drain hole 6 is flush with the inner wall of the C-shaped drain ring 15, allowing the fixing threads to be evenly distributed on both surfaces. When the drain bolt 10 is screwed in, the thread contact area increases, resulting in more even stress on the mating surface. The annular structure of the C-shaped drain ring 15 surrounds the drain hole 6, dispersing shear stress from external vibrations during bolt tightening and preventing localized thread wear or loosening.

[0066] Compared with existing technologies, the oil drain hole 6 of the traditional oil pan 1 is directly opened at the bottom of the oil reservoir 2, and the threaded structure is only set on a single thin wall, which is prone to thread wear or sealing failure due to vibration. In contrast, this solution uses an integrally formed C-shaped oil drain ring 15 to extend the thread bearing area to a double-layer structure. At the same time, the ring support design improves the vibration resistance and solves the defect of easy loosening of traditional single-layer threaded connections.

[0067] Through the above technical solution, this application significantly enhances the reliability of the six threaded connections of the oil drain hole, maintains sealing performance under high-frequency vibration conditions of the aircraft, reduces the risk of oil leakage caused by loose bolts, and the integrated structure reduces processing complexity and maintenance costs.

[0068] This application further proposes that the bolt head 11 of the drain bolt 10 adopts an external hex bolt head 11 or an internal hex bolt head 11, and each side wall plane of the bolt head 11 of the drain bolt 10 is provided with a through anti-loosening limiting hole 14.

[0069] The external hexagonal bolt head 11 or the internal hexagonal bolt head 11 refers to a bolt head 11 with a geometric shape having six planar contact surfaces. This shape can be achieved using a cold forging process, facilitating clamping with standard tools and the application of rotational torque. The anti-loosening limiting through-hole 14 refers to a hole structure penetrating the sidewall plane of the bolt head 11. This hole can be achieved using a drilling process, allowing the insertion of a limiting pin or the passage of an anti-loosening safety wire, forming a mechanical constraint through cooperation with other components.

[0070] Specifically, when the drain bolt 10 is installed in the drain hole 6 of the oil reservoir 2, the structure of the external hexagon or internal hexagon bolt head 11 facilitates tightening using a matching wrench. The anti-loosening limiting through-hole 14 on each sidewall of the bolt head 11 and the set through-hole 13 on the outer bottom surface of the oil reservoir 2 can be connected by a limiting pin or anti-loosening safety wire to form a fixed rigid constraint, preventing the drain bolt from rotating circumferentially due to vibration. During engine operation, the drain bolt head 11 and the outer bottom surface of the oil reservoir 2 are kept fixed by the limiting pin or anti-loosening safety wire, avoiding the risk of loosening caused by high-frequency vibration of traditional bolts.

[0071] Compared to existing technologies, conventional drain bolts rely solely on thread friction for loosening prevention, which is prone to rotational displacement under high-frequency vibration, leading to seal failure. This solution, through the cooperation of a limit pin or anti-loosening safety wire with the through hole, forms an additional mechanical lock after the bolt is tightened. Its anti-loosening mechanism does not rely on thread friction, significantly improving connection reliability.

[0072] Through the above technical solution, this application effectively solves the problem of oil leakage caused by the loosening of the drain plug 10 of the oil pan 1 of the inline engine due to vibration, reduces the maintenance frequency, and improves the ease of assembly through the standardized bolt head 11 design, ensuring the long-term stable operation of the sealing edge of the oil pan 1.

[0073] This application further proposes that a plurality of reinforcing ribs 7 are provided on the smooth connection surface between the upper inner side of the oil pan 1 and the oil storage tank 2, and a reinforcing rib 8 is provided between the inner bottom surface of the oil storage tank 2 and the side wall of the oil storage tank 2.

[0074] Among them, reinforcing rib 7 refers to a transverse or longitudinal protrusion structure located on the upper inner side of the oil pan 1 where it connects to the oil reservoir 2. Specifically, it can be implemented using a metal strip integrally formed with the oil pan 1, with its extension direction parallel to the connecting surface. By enhancing the bending resistance of the connecting surface, it can prevent cracking of the connecting surface caused by high-frequency engine vibration. Reinforcing rib 8 refers to a triangular or trapezoidal protrusion structure located at the junction of the bottom and sidewall of the oil reservoir 2. Specifically, it can be connected to the oil reservoir 2 by welding or casting, and its height can be 1 / 3 to 1 / 2 of the height of the sidewall of the oil reservoir 2. By dispersing the stress on the inner bottom surface and sidewall of the oil reservoir 2, it can suppress deformation of the oil reservoir 2 caused by oil pressure fluctuations.

[0075] Specifically, multiple reinforcing ribs 7 are arranged at intervals along the connection between the upper inner surface of the oil pan 1 and the oil reservoir 2. For example, one rib may be placed at regular intervals or at locations with weaker structural features. The extension direction of each rib is perpendicular to the length of the oil pan 1. When the engine is running, the reinforcing ribs 7 can constrain the elastic deformation of the connection surface under vibration, preventing gaps from forming at the sealing edge due to localized deformation. At the bottom of the oil reservoir 2, reinforcing ribs 8 are fixedly connected to the bottom and sidewalls of the reservoir. When engine oil flows within the oil reservoir 2, the reinforcing ribs 8 can reduce stress concentration at the bottom and sidewalls, maintaining the geometric stability of the oil reservoir 2.

[0076] In some specific embodiments, the shapes of the first reinforcing rib 7 and the second reinforcing rib 8 can be triangular, rectangular, or trapezoidal, and their thickness can be 1-1.5 times the thickness of the oil pan 1 body. The top edge of the second reinforcing rib 8 can be set as a rounded transition structure to avoid turbulence when the oil flows.

[0077] Compared with existing technologies, traditional oil pan 1 lacks reinforcing structures at the connection surface and inside the oil reservoir 2, making it prone to seal failure due to long-term vibration. Deformation of the oil reservoir 2 also increases the risk of loosening of the drain bolt 10. This solution, through a double reinforcing rib design, forms a rigid support network in key stress areas, giving the overall structure of the oil pan 1 better vibration resistance.

[0078] Through the above technical solution, this application effectively solves the problem that the oil pan 1 is prone to structural deformation under high-frequency vibration environment, avoids oil leakage caused by cracking of the connection surface or deformation of the oil reservoir 2, and improves the load-bearing capacity of the oil reservoir 2, making the sealing state of the drain bolt 10 more stable and extending the maintenance cycle.

[0079] This application further proposes that a plurality of assembly bolts 9 are uniformly arranged on the upper sealing edge contact surface 3 of the oil pan 1 for assembly with the engine crankcase assembly.

[0080] The term "uniformly arranged" refers to the arrangement of multiple assembly bolts 9 along the sealing edge contact surface 3 at equal or regular intervals. Specifically, this can be achieved by equally dividing a circle or a straight line distance, thus improving the balance of connection strength through uniform distribution. The assembly bolts 9 are fasteners used to connect the oil pan 1 to the engine crankcase assembly. They can be standard hexagonal head bolts or flange bolts, and the threaded fit and preload ensure the tightness of the sealing edge.

[0081] Specifically, the assembly bolts 9 are arranged at even intervals on the sealing edge contact surface 3. During installation, the sealing gasket is evenly stressed by tightening the bolts sequentially. During the assembly of the oil pan 1 and the engine crankcase assembly, the thread length of the assembly bolts 9 can be adjusted according to the compression of the sealing gasket, ensuring that the sealing gasket forms a continuous and stable sealing interface within the wide-edge contact range. The evenly distributed assembly bolts 9 effectively reduce local pressure differences on the sealing edge contact surface 3, thereby preventing seal failure due to uneven stress.

[0082] Compared with existing technologies, traditional oil pans 1 have fewer or unevenly distributed assembly bolts 9, which easily lead to local stress concentration under vibration, causing gasket deformation or bolt loosening. This solution significantly improves the vibration resistance of the connection structure by increasing the number of evenly distributed assembly bolts 9, while reducing the load fluctuation of individual bolts, so that the sealing edge can still maintain stable contact under dynamic conditions.

[0083] Meanwhile, to adapt to the operating conditions of the unmanned aerial vehicle and to prevent the assembly bolts from loosening, multiple anti-loosening safety holes are provided on the bolt head of each assembly bolt 9. All assembly bolts 9 are sequentially installed through the corresponding anti-loosening safety holes, connecting the assembly bolts 9 together to form a rigid constraint, preventing the assembly bolts 9 from loosening, and significantly improving the vibration resistance and sealing reliability of the connection structure.

[0084] This embodiment also provides an engine equipped with any of the above-mentioned oil pans, which is used in an engine for unmanned aerial vehicles.

[0085] The oil pan refers to the oil pan located at the bottom of the engine crankcase assembly, which has an oil reservoir, oil return port, leak-proof structure, and drain bolt fixing structure. The engine on the unmanned aerial vehicle (UAV) refers to a power unit suitable for low-altitude flight and requiring a compact layout. Specifically, it can be implemented using an inline four-cylinder piston engine. By optimizing the overall structure design of the oil pan, the overall height can be reduced to meet the installation requirements of the aircraft, while also enabling the aircraft to move at large tilt angles of ±45°.

[0086] In unmanned aerial vehicle (UAV) applications, this engine can adapt to the requirements of compact space layout, improving its adaptability to UAVs.

[0087] This embodiment also provides an aircraft equipped with any of the engines described above.

[0088] An aircraft is an airborne vehicle that includes a power system, fuselage, and control system. It can be implemented using a multi-rotor or fixed-wing configuration and is equipped with an engine to provide flight propulsion. The engine is an inline four-cylinder piston engine with an oil pan designed in this application.

[0089] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0090] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An oil pan (1) for an inline piston engine, said oil pan (1) being installed at the lower part of the engine crankcase assembly, characterized in that: The oil pan (1) is formed as a basin-shaped structure with a basically horizontal inner bottom surface. The inner bottom surface of the oil pan (1) is recessed downward to form an oil storage groove (2) that protrudes further outward relative to the outer bottom surface of the oil pan (1). An oil return interface (16) is provided on the upper inner side of the oil pan (1). A through oil drain hole (6) is opened at the bottom of the oil storage groove (2). An oil drain bolt (10) is sealed in the oil drain hole (6). A wide-edge sealing gasket (4) is installed on the sealing edge contact surface (3) where the oil pan (1) connects to the engine crankcase assembly. The width of the wide-edge sealing gasket (4) is greater than the width of the sealing edge contact. The upper end of the oil return port (16) is connected to the oil return device and its engine oil return pipeline system in the crankcase assembly of the engine. The lower end of the oil return port (16) is connected to the stepped surface (17) inside the oil pan (1) that is higher than the oil reservoir (2). The oil return port (16) adopts a C-shaped side wall opening (18) design. The side wall opening (18) of the oil return port (16) is connected to the oil reservoir (2) through the stepped surface (17) of the oil pan (1). The bolt head (11) of the drain bolt (10) is in tight contact with the outer bottom surface of the oil reservoir (2). The outer bottom surface of the oil reservoir (2) is provided with a limiting protrusion (12) corresponding to the side of the bolt head (11) of the drain bolt (10). The limiting protrusion (12) is provided with a tightening through hole (13) facing the bolt head (11) of the drain bolt (10). The bolt head (11) of the drain bolt (10) is provided with an anti-loosening limiting through hole (14). A limiting pin or an anti-loosening safety wire is provided through the tightening through hole (13) and the anti-loosening limiting through hole (14).

2. The oil pan (1) of an inline piston engine according to claim 1, characterized in that: The outer edge of the wide-side sealing gasket (4) is flush with the outer edge of the sealing edge contact surface (3).

3. The oil pan (1) of an inline piston engine according to claim 1, characterized in that: The oil reservoir (2) is located at the center of the oil pan (1). The outer bottom surface of the oil pan (1) and the outer side wall of the oil reservoir (2) are smoothly connected. The vertical space between the horizontal plane of the outer bottom surface of the oil reservoir (2) and the outer bottom surface of the oil pan (1) constitutes the exhaust pipe installation space. The exhaust pipe of the engine crankshaft housing assembly is installed in the exhaust pipe installation space outside the oil pan (1).

4. The oil pan (1) of an inline piston engine according to claim 3, characterized in that: Inside the oil pan (1), a stepped surface (17) higher than the oil storage tank (2) is vertically provided with an oil guide plate (19) corresponding to the oil return interface (16), and one end of the oil guide plate (19) is connected to the side opening (18) of the oil return interface (16) near the oil storage tank (2).

5. The oil pan (1) of an inline piston engine according to claim 3, characterized in that: The center hole at the connection between the stepped surface (17) inside the oil pan (1) that is higher than the oil storage tank (2) and the return oil interface (16) is designed as a recessed hole (20), and there is a smooth transition between the recessed hole (20) and the stepped surface (17) inside the oil pan (1) that is higher than the oil storage tank (2).

6. The oil pan (1) of an inline piston engine according to claim 3, characterized in that: The bottom of the oil storage tank (2) is provided with a C-shaped drain ring (15) integrated with the oil pan (1) at the drain hole (6). The side notch of the C-shaped drain ring (15) is connected to the bottom surface of the oil storage tank (2). The inner wall of the C-shaped drain ring (15) is flush with the inner wall of the drain hole (6). The inner wall of the C-shaped drain ring (15) and the inner wall of the drain hole (6) are provided with fixing threads that match the drain bolt (10).

7. The oil pan (1) of an inline piston engine according to claim 6, characterized in that: The bolt head (11) of the drain bolt (10) is an external hexagonal bolt head (11) or an internal hexagonal bolt head (11), and each side wall plane of the bolt head (11) of the drain bolt (10) is provided with a through anti-loosening limiting through hole (14).

8. The oil pan (1) of an inline piston engine according to claim 1, characterized in that: A plurality of reinforcing ribs (7) are provided on the smooth connecting surface between the upper inner side of the oil pan (1) and the oil storage tank (2), and reinforcing ribs (8) are provided between the inner bottom surface of the oil storage tank (2) and the side wall of the oil storage tank (2).

9. The oil pan (1) of an inline piston engine according to claim 1, characterized in that: The upper part of the oil pan (1) is evenly provided with a plurality of mounting bolts (9) that connect the oil pan (1) and the bottom of the engine crankcase assembly. Each mounting bolt (9) has a plurality of anti-loosening safety holes on its bolt head. All the mounting bolts (9) are sequentially installed through the corresponding anti-loosening safety holes.

10. An engine, characterized in that, It is equipped with an oil pan according to any one of claims 1-9.

11. An aircraft, characterized in that, It is equipped with the engine as described in claim 10.

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