A compact in-line piston engine crankcase body and gear cover mating structure, engine and aircraft thereof

Abstract

The utility model relates to a piston engine for unmanned aerial vehicle technical field especially a compact inline piston engine crankshaft box body and gear cover cooperation structure, engine and its aircraft, the crankshaft box body including each other cooperation setting upper box and lower box, the upper box and lower box cooperation form the crankshaft mounting space for installing crankshaft in, the crankshaft box body one side setting is the crankshaft power output end, the crankshaft box body on the crankshaft power output end place cooperation setting has the power output gear cover, the power output gear cover includes the box end gear cover and output shaft gear cover, the box end gear cover is connected with the crankshaft power output end on the crankshaft box body cooperation, output shaft gear cover and box end gear cover connection cooperation, the utility model discloses the optimization to the crankshaft box body structure has realized the box miniaturization design, has effectively improved the engine structure compactness and power transmission efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of piston engines for unmanned aerial vehicles, specifically to a compact inline piston engine crankcase and gear cover mating structure, the engine, and the aircraft thereof. Background Technology

[0002] In recent years, drones using four-cylinder piston engines directly driving propellers, typical of small manned aircraft, have gradually entered the market. However, the mainstream four-cylinder piston engines for small manned aircraft currently on the market generally adopt a horizontally opposed arrangement. While this layout has the advantage of good balance, it also has significant structural defects. Horizontally opposed engines require symmetrical arrangement of core components such as the cylinder block, cylinder head, cylinder head, and camshaft, resulting in a significant increase in the number of parts, which not only increases manufacturing costs but also significantly increases the engine's weight. This structural layout is particularly unfavorable for drone applications requiring lightweight design, severely impacting the aircraft's payload and endurance. Furthermore, the crankcase and gear cover mating structure of traditional horizontally opposed engines is relatively complex, resulting in a long power transmission path, which is not conducive to achieving a compact design. Especially in applications requiring the integration of auxiliary devices such as starter motors and water pumps, the existing structure often results in an excessively large overall engine size, making it difficult to meet the stringent requirements of modern drones for miniaturized and lightweight power systems. Therefore, existing technologies urgently need improvement to address these issues. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a compact crankcase and gear cover mating structure for an inline piston engine, an engine and its aircraft.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a compact crankshaft housing and gear cover mating structure for an inline piston engine. The crankshaft housing includes an upper housing and a lower housing that are mated together. The upper and lower housings form a crankshaft mounting space for mounting the crankshaft. The mating surfaces of the upper and lower housings are parallel to each other, with the crankshaft rotation center and the damping gear shaft center positioned parallel to each other. A piston connecting rod assembly that mates with the crankshaft is provided on the upper part of the upper housing. A starting device mounting space and a water pump mounting space are provided on the side of the upper housing. A starter motor is mounted in the starting device mounting space, and the starter motor is connected to... The crankshaft is connected via gear linkage. A water pump is installed in the water pump installation space, and the water pump shaft is connected to the crankshaft via gear linkage. An oil cooler assembly is fitted on the outer surface of one side of the lower housing. An oil pump is fitted on the inner surface of the lower housing near the oil cooler assembly. One side of the crankshaft housing is set as the crankshaft power output end. A power output gear cover is fitted on the crankshaft housing at the crankshaft power output end. The power output gear cover includes a housing end gear cover and an output shaft gear cover. The housing end gear cover is connected to the crankshaft power output end on the crankshaft housing, and the output shaft gear cover is connected to the housing end gear cover.

[0005] In some embodiments, the gear cover at the end of the housing is provided with a shock-absorbing gear assembly and a starting gear assembly, which are respectively connected to the crankshaft.

[0006] In some embodiments, a power transmission assembly is provided inside the output shaft gear cover, the inner end of the power transmission assembly is connected to the shock-absorbing gear assembly, and the outer end of the power transmission assembly is located on the outer side of the output shaft gear cover.

[0007] In some embodiments, the shaft end of the starter motor extends into the gear cover at the end of the housing and is connected to the starter gear assembly.

[0008] In some embodiments, the pump shaft extends into the gear cover at the end of the housing and is linked to the shock-absorbing gear assembly.

[0009] In some embodiments, the starting device mounting space and the water pump mounting space are located on the same side of the upper housing.

[0010] In some embodiments, the mounting space for the oil cooler assembly is located outside the lower housing on the same side as the mounting space for the starting device and the water pump.

[0011] In some embodiments, the center of the oil pump shaft and the center of the water pump shaft are respectively located above and below the center of the damping gear shaft.

[0012] To achieve the above objectives, this utility model provides the following technical solution: an engine equipped with the aforementioned crankcase and gear cover mating structure.

[0013] To achieve the above objectives, this utility model provides the following technical solution: an aircraft equipped with the aforementioned engine.

[0014] Compared with the prior art, the beneficial effects of this utility model are: by forming a crankshaft installation space through the cooperation of the upper and lower housings, and integrating the starting device and water pump installation space on the side, and combining the gear cover at the end of the housing and the output shaft gear cover at the power output end, the engine structure is effectively simplified, the power transmission path is shortened, the number of parts and weight are reduced, and the auxiliary devices are conveniently arranged. It has the advantages of compact structure, lightweight, high power transmission efficiency and convenient integration of auxiliary devices.

[0015] 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

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram showing the fit between the upper and lower housings; Figure 3 This is a side view of the enclosure; Figure 4 A schematic diagram showing the connection of the starting gear assembly inside the gear cover at the end of the housing; Figure 5 A schematic diagram showing the connection between the water pump and oil pump inside the gear cover at the end of the housing and the shock-absorbing gear assembly; Figure 6 This is a schematic diagram showing the connection between the shock-absorbing gear assembly and the power transmission assembly.

[0017] In the diagram: 1. Crankcase; 2. Upper crankcase; 3. Lower crankcase; 4. Gear cover at the end of the crankcase; 5. Output shaft gear cover; 6. Cylinder block and cylinder head assembly; 7. Piston and connecting rod assembly; 8. Magneto cover; 9. Oil pan; 10. Starter motor; 11. Water pump; 12. Oil cooler assembly; 13. Crankshaft mounting space; 14. Crankshaft power output end; 15. Starter gear assembly; 16. Vibration damping gear assembly; 17. Power transmission assembly; 18. Crankshaft rotation center; 19. Vibration damping gear shaft center; 20. Starter motor shaft center; 21. Water pump shaft center; 22. Oil pump shaft center; 24. Oil pump. Detailed Implementation

[0018] 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.

[0019] In existing technologies, four-cylinder piston engines for small manned aircraft generally adopt a horizontally opposed arrangement, requiring symmetrical arrangement of core components such as the cylinder block and cylinder head, resulting in an increased number of parts and a larger overall weight. Although inline four-cylinder piston engines can reduce the redundancy caused by symmetrical structures, they still suffer from loose layout and low power transmission efficiency in applications such as UAVs or small manned aircraft. In particular, the mating structure between the crankcase and gear cover fails to effectively integrate auxiliary components such as the starting device and water pump, affecting compactness and ease of maintenance.

[0020] To address the aforementioned issues, a highly integrated crankcase and gear cover mating structure needs to be designed for inline engines. The inventors discovered that horizontally opposed engines, due to their symmetrical arrangement, result in a large number of components. While an inline layout reduces symmetry constraints, existing technologies often involve dispersed components such as the starting device and water pump, occupying significant space and creating complex transmission paths. By centralizing auxiliary components on the same side of the crankcase and optimizing the split design of the gear cover, the transmission chain can be simplified, weight reduced, and space utilization improved.

[0021] Therefore, as Figures 1 to 6 As shown, this application proposes a compact crankcase and gear cover mating structure for an inline piston engine, including an upper housing 2 and a lower housing 3 that mate with each other, forming a crankshaft mounting space 13; a crankshaft rotation center 18 and a damping gear shaft center 19 are arranged parallel to each other on the mating surfaces of the upper housing 2 and the lower housing 3; a cylinder block and cylinder head assembly 6 is provided on the upper part of the upper housing 2, and a piston connecting rod assembly 7 that is linked to the crankshaft is arranged inside the cylinder block and cylinder head assembly 6; a starter motor 10 and a water pump 11 are provided on the side of the upper housing 2. The drive shaft of the motor 10 extends into the interior of the upper housing 2 and is connected to the crankshaft via the starting gear assembly 15. The water pump 11 is installed on the outside of the upper housing 2, and its drive shaft extends into the interior of the upper housing 2 and is connected to the crankshaft via gears. One end of the crankshaft housing 1 is the crankshaft power output end 14. The outside of the crankshaft power output end 14 is provided with a power output gear cover consisting of a housing end gear cover 4 and an output shaft gear cover 5. The housing end gear cover 4 is connected to the crankshaft power output end 14, and the output shaft gear cover 5 is connected to the housing end gear cover 4.

[0022] The crankshaft mounting space 13 refers to the cavity formed by assembling the upper housing 2 and the lower housing 3, used to accommodate the crankshaft and bearings. It can be achieved through separate machining followed by bolt fastening, facilitating crankshaft installation and maintenance. The piston connecting rod assembly 7 refers to the piston connecting rod mechanism linked to the crankshaft, specifically using a forged aluminum alloy piston and a forged alloy steel connecting rod, working with the crankshaft to transmit power. The mounting space for the starter motor 10 and water pump 11 refers to two independent cavities located on the side of the upper housing 2, specifically achieved by setting a boss structure on the side wall of the housing and reserving mounting holes, used to fix the starter motor 10 and water pump 11. The housing end gear cover 4 refers to the housing assembly covering the power output end 14 of the housing. The housing end gear cover 4 uses an aluminum alloy housing with rubber shock-absorbing pads, while the output shaft gear cover 5 uses a separate flange connection structure. Both are fixed by locating pins and bolts. This separate design allows for separate power transmission and vibration isolation.

[0023] Specifically, the upper housing 2 and the lower housing 3 are assembled after precision machining to form a closed crankshaft mounting space 13. The crankshaft is supported in this cavity by the main bearing. The crankshaft rotation center 18, the damping gear shaft center 19, and the crankshaft power output end 14 flange face all need to be machined as a whole after the upper housing 2 and the lower housing 3 are assembled to ensure the precision requirements of the engine.

[0024] The starter motor 10 and water pump 11 are respectively embedded in the installation space on the same side of the upper housing 2. Their respective shafts extend into the internal space of the crankshaft housing 1 near the gear cover 4 at the end of the housing. Finally, the power transmission of the engine starting device and the cooling system drive device is realized by the gear meshing with the transmission gear at the end of the crankshaft.

[0025] An oil cooler assembly 12 is installed on the outer surface of the lower housing 3 near the oil pan. It is located on the same side of the crankcase 1 as the starter motor 10 and the water pump 11, and is arranged in a three-dimensional staggered manner to achieve the overall miniaturization design of the engine.

[0026] The lower housing 3 has an oil pump installation space located near the oil pan 9 and the oil cooler assembly 12, which optimizes the path of lubricating oil from the oil pan 9, oil pump 24, oil cooler assembly 12 to the main oil passage of the lower housing 3.

[0027] The water pump shaft center 21 and the oil pump shaft center 22 are located on the upper and lower sides of the damping gear shaft center 19, respectively. The cooling system and the lubrication system share a drive gear that is coaxially set with the damping gear assembly, and operate synchronously with the crankshaft power.

[0028] The crankshaft rotation center 18 and the damping gear shaft center 19 are at the same height and are both located at the joint surface of the upper housing 2 and the lower housing 3, which facilitates the installation and maintenance of the crankshaft and damping gear assembly.

[0029] The gear cover 4 at the end of the housing is connected to the crankshaft housing 1 via a flange face, and a damping gear assembly 16 is installed inside to absorb crankshaft vibration; the output shaft gear cover 5 is connected to the gear cover 4 at the end of the housing via bolts, and a power output shaft extends from its outer end to drive external loads. This layout concentrates auxiliary systems such as starting and cooling on the same side of the housing, shortens the gear transmission chain length, and the split gear cover design facilitates disassembly and maintenance.

[0030] The split gear cover in this design allows for individual replacement of the damping components or output shaft seals, significantly improving maintenance efficiency. It also enables the assembly of a crankshaft, transmission device, and final output shaft flange that integrates the load-bearing gear. Furthermore, the gear linkage design between the starter motor and water pump avoids the slippage risk associated with belt drives, improving transmission efficiency.

[0031] Through the above technical solution, this application achieves a compact fit between the crankcase and gear cover of an inline engine, reducing the number of parts and overall weight. Simultaneously, the split gear cover design improves maintenance convenience. The centralized arrangement of auxiliary components shortens the transmission path, reduces power loss, and the rigid gear linkage enhances system reliability, making it suitable for space- and weight-sensitive unmanned aerial vehicles (UAVs) or small manned aircraft power systems. This application further proposes that the gear cover 4 at the end of the housing is provided with a starting gear assembly 15 and a shock-absorbing gear assembly 16, which are respectively connected to the crankshaft.

[0032] The gear cover 4 at the end of the housing refers to the shell structure installed outside the crankshaft power output end 14, used to house the starter gear assembly 15 and the damping gear assembly 16. Specifically, it can be formed with an internal cavity structure using aluminum alloy casting technology to achieve lightweight and high strength. The damping gear assembly 16 is a transmission module composed of multiple gears and damping elements, used to absorb the vibration energy generated during crankshaft operation. The starter gear assembly 15 is the transmission mechanism connecting the starter motor 10 and the crankshaft, used to transmit the power of the starter motor to the crankshaft to complete the initial engine operation.

[0033] Specifically, the damping gear assembly 16 includes a damping gear. Multiple mounting cavities are evenly arranged around the inner circumference of the damping gear, penetrating the side of the damping gear. Each mounting cavity is provided with a damping spring along the circumference, and the size of the mounting cavity corresponding to each damping spring is adapted to the corresponding damping spring. A base and a pressure plate are respectively provided on both sides of the damping gear. The inner surfaces of the base and the pressure plate are provided with symmetrical grooves corresponding to each damping spring. Finally, the damping gear, the base and the pressure plate are assembled into a whole structure damping gear assembly using three bolts evenly arranged along the circumference.

[0034] The damping gear is directly meshed with the drive gear integrally formed on the crankshaft. When the crankshaft rotates, the power is transmitted to the damping gear assembly 16 through gear meshing. Its internal damping structure can buffer the periodic impact load of the crankshaft. The impact load is transmitted to the base and finally to the drive shaft of the damping gear assembly through the internal spline of the base. This realizes the indirect power transmission between the damping gear and the power transmission assembly, achieving an effective damping effect.

[0035] The starter gear assembly 15 is located inside the gear cover 4 at the end of the housing, near the upper housing. The starter gear assembly 15 includes a starter gear and a reduction gear assembly. The shaft of the starter motor directly drives the reduction gear assembly through gear meshing. The reduction gear assembly has a transmission gear coaxially arranged, which ultimately drives the starter gear integrated with the crankshaft through an idler wheel. The starter gear integrates a one-way overrunning clutch assembly, so that when the crankshaft speed is lower than the starter motor speed, the torque of the starter motor is applied to the crankshaft.

[0036] The shock-absorbing gear assembly 16 and the starting gear assembly 15 are arranged in parallel within the internal space of the gear cover at the end of the housing. They are connected to the crankshaft through independent transmission paths to avoid interference in power transmission.

[0037] Compared to existing technologies, the damping devices and starting transmission mechanisms of traditional engines are usually distributed in different locations. For example, the damping gear is installed inside the crankcase while the starting transmission mechanism is located outside the gear cover, resulting in a loose structure and a large space occupation. This solution integrates the damping and starting functional modules inside the same end gear cover of the crankcase, reducing the number of external connecting parts through a compact spatial layout, while also reducing assembly complexity.

[0038] Through the above technical solution, this application solves the problem of increased axial length caused by the dispersed arrangement of the shock-absorbing transmission mechanism and the starting device in traditional inline engines. By integrating functional modules, the overall volume of the gear cover is reduced, while the transmission chain length at the crankshaft power output end is reduced, thereby improving power transmission efficiency and structural stability. This application further proposes that a power transmission assembly 17 is provided inside the output shaft gear cover 5, the input end of the power transmission assembly 17 is connected to the shock-absorbing gear assembly 16, and the output end of the power transmission assembly 17 passes through the output shaft gear cover 5 and is connected to an external load device.

[0039] The power transmission assembly 17 refers to the mechanical connection device that transmits crankshaft power outward. Specifically, it can be implemented using a gear set or coupling structure. The input end connects to the damping gear assembly to receive crankshaft power, and the output end extends to the outside of the gear cover for connecting to an external transmission device. The output shaft gear cover 5 refers to the housing covering the power transmission assembly 17. Specifically, it can be implemented using an aluminum alloy housing. The output end is equipped with a flange or coupling for mounting and positioning the power output interface.

[0040] Specifically, the power transmission assembly 17 is integrated inside the output shaft gear cover 5. Its input end is connected to the damping gear assembly 16 via spline engagement, and its output end extends through the side wall of the gear cover to the outside and is connected to an external load device via a flange or coupling. The crankshaft power is transmitted sequentially to the external transmission device through the damping gear assembly 16 and the power transmission assembly 17. The transmission path is constrained within the internal space of the output shaft gear cover 5, and the output shaft gear cover 5 has a sealing structure at the output end opening to prevent lubricating oil leakage. The power transmission assembly 17 uses spur gears or helical gears, and the gear axes are all arranged parallel to the crankshaft rotation center 18 to reduce space occupation.

[0041] This solution integrates the power transmission assembly 17 inside the output shaft gear cover 5, creating a compact coaxial layout between the damping gear assembly 16 and the input shaft of the power transmission assembly 17, thereby shortening the axial length of the power transmission path.

[0042] Through the above technical solution, this application realizes the axial space compression of the engine power output mechanism, avoiding the problem of increased engine length caused by the traditional split transmission structure. While ensuring the stability of power transmission, it makes the overall size of the inline engine more suitable for space-constrained application scenarios such as drones. This application further proposes that the shaft end of the starter motor 10 extends into the interior of the gear cover 4 at the end of the housing and is connected to the starter gear assembly 15.

[0043] The shaft end of the starter motor 10 refers to the end of the shaft from which the drive motor outputs power. Specifically, it can be implemented using a rigid shaft or a segmented shaft structure. Its function is to directly transmit the rotational power of the motor to the inside of the gear cover 4 at the end of the housing and to establish a power transmission path between the motor and the crankshaft.

[0044] Specifically, the shaft end of the starter motor 10 passes through the side wall of the upper housing 2 and extends into the interior of the gear cover 4 at the end of the housing, forming a rigid connection with the starter gear assembly 15 through gear meshing. When the starter motor 10 starts, the rotational motion of the shaft end is directly transmitted to the starter gear assembly 15, thereby driving the crankshaft to rotate. Since the shaft end is completely embedded inside the gear cover 4 at the end of the housing, the power transmission path is shortened, avoiding energy loss caused by external transmission structures. At the same time, the internal space layout of the gear cover 4 at the end of the housing allows for a tighter fit between the starter gear assembly 15 and the shock-absorbing gear assembly 16, reducing transmission clearance.

[0045] Through the above technical solution, this application solves the problems of loose layout and low transmission efficiency of traditional engine starter motors, reduces energy loss by shortening the power transmission path, and improves structural stability by utilizing the internal space integration design of the gear cover 4 at the end of the housing, making the engine start response faster and the operation more reliable. This application further proposes that the shaft end of the water pump 11 extends into the interior of the gear cover 4 at the end of the housing and is linked to the shock-absorbing gear assembly 16.

[0046] The rotating shaft end of the water pump 11 refers to the part of the water pump drive shaft that extends into the gear cover 4 at the end of the housing. Specifically, it can adopt a spline or coupling structure to transmit the crankshaft power to the water pump impeller.

[0047] Specifically, the shaft of the water pump 11 is directly linked to the damping gear assembly 16 via gear meshing. When the crankshaft rotates, power is transmitted to the shaft of the water pump 11 through the damping gear assembly 16, ultimately driving the water pump impeller. Since the shaft end extends directly into the interior of the gear cover 4 at the end of the housing, the power input path of the water pump 11 is integrated into the gear transmission system at the crankshaft power output end, eliminating the need for a separate water pump drive chain or pulley structure.

[0048] This solution integrates the water pump power transmission path into the internal space of the gear cover at the end of the housing, thus creating a compact axial layout between the cooling system's drive mechanism and the crankcase.

[0049] Through the above technical solution, this application achieves spatial reuse of the water pump drive mechanism and the crankshaft power output system, reducing the number of independent transmission components. This structure effectively shortens the axial length of the water pump power transmission path, avoids the problem of complex cooling system transmission structure caused by the symmetrical layout of traditional horizontally opposed engines, and reduces the assembly complexity of the gear transmission system. This application further proposes installing an oil pump 24 on the side wall inside the lower housing 3 near the oil cooler assembly 12. The oil pump 24 integrates a linkage gear, which is linked to the shock-absorbing gear assembly 16. The installation space of the oil pump 24 is located inside the gear cover 4 at the end of the housing, close to the oil pan 9, forming the shortest path for lubricating oil to enter the main oil passage of the lower housing 3.

[0050] Specifically, the shaft of the oil pump 24 is directly linked to the damping gear assembly 16 via gear meshing. When the crankshaft rotates, power is transmitted to the oil pump shaft through the damping gear assembly 16, driving the oil pump impeller. Since the oil pump 24 is directly installed inside the gear cover 4 at the end of the housing, the power input path of the oil pump 24 is integrated into the gear transmission system at the crankshaft power output end, eliminating the need for a separate drive chain or pulley structure.

[0051] This solution integrates the oil pump 24 inside the gear cover 4 at the end of the housing, creating a compact overall layout for the lubrication system and the crankshaft power transmission system.

[0052] Through the above technical solution, this application realizes that the oil pump drive mechanism and water pump share the output power of the crankshaft, achieving spatial reuse of multiple drive systems and reducing the number of independent transmission components. This structure effectively shortens the axial length of the oil pump power transmission path, avoids the problem of complicated transmission structure of the lubrication and cooling system caused by the symmetrical layout of traditional horizontally opposed engines, and reduces the assembly complexity of the gear transmission system. This application further proposes that the installation space for the starter motor 10 and the installation space for the water pump 11 are located on the same side of the upper housing 2.

[0053] The installation space for the starter motor 10 refers to the cavity structure used to accommodate the starter motor. Specifically, it can be achieved by using an inwardly recessed mounting groove formed by the side wall of the housing, the depth and shape of which are designed to match the size of the starter motor. The installation space for the water pump 11 refers to the positioning area used to fix the water pump. Specifically, it can be achieved by a boss structure extending outward from the side wall of the housing, with bolt holes on the surface of the boss for fixing the water pump. The same side of the upper housing 2 refers to the space area on the side of the housing closest to the engine intake system. Specifically, the two installation spaces can be integrated into adjacent positions on the same side wall of the housing using a casting process, allowing them to share the spatial layout of the same side.

[0054] Specifically, the mounting spaces for the starter motor 10 and the water pump 11 are located in adjacent areas on the same side of the upper housing 2. The drive shaft of the starter motor 10 and the rotating shaft of the water pump 11 are respectively linked to the crankshaft via gear transmission mechanisms. The layout of the mounting spaces allows the gear sets of the two transmission paths to share the support structure on the same side, reducing the lateral space required for gear transmission. The power harness of the starter motor 10 and the cooling pipes of the water pump 11 can be centrally arranged along the same side of the housing, avoiding interference problems caused by the harness and pipes crossing different sides of the housing.

[0055] This solution shortens the gear drive chain length and reduces the number of independent mounting points for the support structure by integrating both components on the same side of the crankcase, while also concentrating maintenance operations on a single working surface.

[0056] Through the above technical solution, this application solves the problems of high assembly complexity and low maintenance efficiency caused by the dispersed layout of components in traditional engines, realizes the compact design of transmission path, reduces the vibration risk of gear transmission system, and makes centralized management of external wiring harness and pipeline possible. This application further proposes an engine equipped with a crankcase 1 and a gear cover. The crankcase 1 includes an upper case 2 and a lower case 3 that are mutually fitted together. The upper case 2 and the lower case 3 cooperate to form a crankshaft mounting space 13 for mounting the crankshaft. A crankshaft rotation center 18 and a damping gear shaft center 19 are arranged parallel to each other on the mating surfaces of the upper case 2 and the lower case 3. A cylinder block and cylinder head assembly 6 and a piston connecting rod assembly 7 that cooperates with the crankshaft are provided on the upper part of the upper case 2. A starter motor mounting space and a water pump mounting space are provided on the side of the upper case 2. The starter motor 10 is installed in the starter motor mounting space and is connected to the crankshaft through gear linkage. The water pump 11 is installed in the water pump mounting space and its shaft is connected to the crankshaft through gear linkage.

[0057] One end of the crankshaft housing 1 is configured as the crankshaft power output end 14 and is fitted with a power output gear cover. The power output gear cover includes a housing end gear cover 4 and an output shaft gear cover 5. The housing end gear cover 4 is connected to the crankshaft power output end 14, and the output shaft gear cover 5 is connected to the housing end gear cover 4.

[0058] The crankcase and gear cover assembly structure refers to the support structure of the power transmission system formed by the assembly relationship between the split crankcase and the modular gear cover. Specifically, it can be achieved using aluminum alloy cast crankcase and gear cover blanks combined with high-precision machining. This structure reduces the overall weight by minimizing the number of symmetrically arranged parts. The end gear cover 4 of the crankcase refers to the housing structure covering the shock-absorbing gear assembly 16 and the starting gear assembly 15. Specifically, it can be implemented using a gear bracket structure with embedded rubber damping blocks to absorb the vibration energy generated during crankshaft operation. The output shaft gear cover 5 refers to a sealed housing containing the power output interface. Specifically, it can be implemented using a flange-connected housing structure, with multiple reduction gear sets inside to adapt to different load requirements.

[0059] Specifically, the engine integrates the starter motor and water pump on the same side of the crankcase, concentrating the gear transmission system in the power output area. Crankshaft power is transmitted to the output shaft gear cover 5 via a damping gear assembly 16 located inside the gear cover 4 at the end of the crankcase. The output shaft gear cover 5 has a power output interface on its outer side for connecting load equipment such as propellers.

[0060] Compared to existing technologies, horizontally opposed engines require a symmetrical arrangement of the cylinder block, cylinder head, and camshaft, doubling the number of parts. This solution, however, uses an inline layout, allowing the crankcase to have auxiliary devices arranged on only one side. The gear cover employs a layered modular design instead of the traditional integral cast housing. Traditional horizontally opposed engine cylinder block machining requires two sets of tooling fixtures, one on each side, while the inline crankcase can be machined using a single production line.

[0061] Through the above technical solutions, the engine reduces approximately 40% of symmetrical parts while maintaining the same power output. The axial dimension of the gear transmission system is shortened, and the overall weight is reduced compared to similar horizontally opposed engine models. The separate design of the housing and gear cover allows for maintenance of the water pump and starter motor without disassembling the entire power system. This application further proposes an aircraft equipped with an engine having the above-described structure. The engine is equipped with a crankshaft housing and gear cover mating structure. The crankshaft housing 1 includes an upper housing 2 and a lower housing 3 that are mated to each other. The upper housing 2 and the lower housing 3 are mated to form a crankshaft mounting space 13 for mounting the crankshaft. The upper part of the upper housing 2 is provided with a piston connecting rod assembly 7 that mates with the crankshaft. The side of the upper housing 2 is provided with a starting device mounting space and a water pump mounting space. A starter motor 10 is installed in the starting device mounting space and is connected to the crankshaft via gear linkage. A water pump 11 is installed in the water pump mounting space and its shaft is connected to the crankshaft via gear linkage. One end of the crankshaft housing is provided as a crankshaft power output end 14. A power output gear cover is provided on the outside of the crankshaft power output end 14. The power output gear cover includes a housing end gear cover 4 and an output shaft gear cover 5. The housing end gear cover 4 is connected to the crankshaft power output end 14, and the output shaft gear cover 5 is connected to the housing end gear cover 4.

[0062] Among them, an inline piston engine refers to an engine in which the cylinders are arranged in a single row along the crankshaft axis, specifically a four-cylinder inline layout, reducing overall weight by minimizing symmetrically arranged components. The power output gear cover is a housing structure covering the power output end of the crankshaft, specifically a modular design that allows for the assembly of the housing end gear cover 4 and the output shaft gear cover 5, reducing vibration transmission in the gear transmission system through this modular structure. The housing end gear cover 4 is the housing that houses the damping gear assembly 16 and the starting gear assembly 15, specifically implemented using a rubber damper in conjunction with the gear shaft, absorbing high-frequency vibrations from the crankshaft output to improve power transmission stability.

[0063] Specifically, the aircraft is equipped with an inline engine, integrating the starter motor 10 and water pump 11 on the same side of the crankcase, using gear linkage to achieve linkage with the crankshaft. The crankshaft power output end 14 is equipped with a gear cover 4 at the end of the crankcase, allowing the vibration damping transmission mechanism 16 and the crankshaft power output shaft to form an independent sealed cavity, suppressing vibration transmission to the aircraft fuselage while transmitting crankshaft power. The crankcase adopts a split upper and lower assembly, facilitating the machining and maintenance of the crankshaft installation space.

[0064] In some specific embodiments, a shock-absorbing bracket can be installed inside the engine nacelle to secure the crankcase, and the propeller drive shaft can be connected to the outside of the output shaft gear cover. A multi-stage gear reduction mechanism, such as a helical gear set, can be arranged inside the gear cover at the end of the crankcase to reduce transmission noise.

[0065] Through the above technical solution, this application solves the problems of redundant parts and excessive weight caused by the symmetrical structure of horizontally opposed engines. The inline layout combined with the split gear cover design makes the engine structure compact and the vibration controllable, which is suitable for large industrial-grade UAVs or small manned aircraft with high requirements for thrust-to-weight ratio and space utilization.

[0066] 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.

[0067] 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. A compact in-line piston engine crankcase and gear cover mating structure, characterized by: The crankcase includes an upper case and a lower case that cooperate with each other. The upper and lower cases form a crankshaft mounting space for mounting the crankshaft. The mating surfaces of the upper and lower cases are parallel to each other, aligning with the crankshaft rotation center and the damping gear shaft center. A piston connecting rod assembly that mates with the crankshaft is located on the upper part of the upper case. A starting device mounting space and a water pump mounting space are located on the side of the upper case. A starter motor is mounted in the starting device mounting space and is connected to the crankshaft via gear linkage. A water pump is mounted in the water pump mounting space. The water pump shaft is connected to the crankshaft via gear linkage. An oil cooler assembly is fitted on the outer surface of one side of the lower housing. An oil pump is fitted on the inner surface of the lower housing near the oil cooler assembly. One side of the crankshaft housing is configured as the crankshaft power output end. A power output gear cover is fitted on the crankshaft housing at the crankshaft power output end. The power output gear cover includes a housing end gear cover and an output shaft gear cover. The housing end gear cover is connected to the crankshaft power output end on the crankshaft housing, and the output shaft gear cover is connected to the housing end gear cover.

2. A compact in-line piston engine crankcase and gear cover mating structure according to claim 1, characterized in that: The gear cover at the end of the housing is equipped with a shock-absorbing gear assembly and a starting gear assembly, which are respectively connected to the crankshaft.

3. A compact in-line piston engine crankcase and gear cover mating structure according to claim 2, characterized in that: A power transmission assembly is installed inside the output shaft gear cover. The input end of the power transmission assembly is connected to the shock-absorbing gear assembly, and the output end of the power transmission assembly is located outside the output shaft gear cover.

4. The compact crankcase and gear cover mating structure for an inline piston engine according to claim 2, characterized in that: The shaft end of the starter motor extends into the gear cover at the end of the housing and is connected to the starter gear assembly.

5. The compact crankcase and gear cover mating structure for an inline piston engine according to claim 2, characterized in that: The water pump's shaft extends into the gear cover at the end of the housing and is linked to the shock-absorbing gear assembly.

6. A compact crankcase and gear cover mating structure for an inline piston engine according to claim 1, 4, or 5, characterized in that: The installation space for the starting device and the installation space for the water pump are located on the same side of the upper housing.

7. The compact crankcase and gear cover mating structure for an inline piston engine according to claim 6, characterized in that: The installation space for the oil cooler assembly is located outside the lower housing on the same side as the installation space for the starting device and the water pump.

8. The compact crankcase and gear cover mating structure for an inline piston engine according to claim 7, characterized in that: The center of the oil pump shaft and the center of the water pump shaft are respectively located above and below the center of the damping gear shaft.

9. An engine equipped with a crankcase and gear cover mating structure according to any one of claims 1-8.

10. An aircraft equipped with an engine according to claim 9.

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