Transmission assembly of in-line piston engine, engine and aircraft thereof

Abstract

The utility model relates to the technical field of engine crankshaft power transmission, in particular to a transmission assembly of an in-line piston engine, an engine and an aircraft thereof, which comprise a crankshaft body, the crankshaft body comprises a plurality of crank pins, a plurality of cranks and a plurality of journals which are sequentially arranged in a staggered manner from the front end to the tail end, a driving gear is arranged at the front end of the crankshaft body and integrally formed with the crank, the center of the driving gear and a shaft neck of the crankshaft body are arranged on the same central axis, a transmission mechanism is arranged outside the driving gear in an engaged mode, and the transmission mechanism comprises a damping gear assembly, a transmission gear, an idle gear and an output gear which are sequentially engaged. The integral layout is optimized, the structure is compact, the simple idle gear is additionally arranged, an original idle gear shaft transmission mechanism is replaced, the basic function of speed reduction of an engine is achieved, and meanwhile the purposes of miniaturization, light weight, stability and aircraft carrying performance of the engine are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of engine crankshaft power transmission, and specifically relates to a transmission component of an in-line piston engine, an engine and an aircraft thereof. Background Art

[0002] In recent years, drones (UAVs) using 4-cylinder piston engines designed for small manned aircraft to directly drive their propellers have gradually entered the market. However, the mainstream 4-cylinder piston engines for small manned aircraft currently use a horizontally opposed arrangement, while UAVs using inline 4-cylinder piston engines are still relatively rare. In large industrial UAVs or small manned aircraft, the application of inline 4-cylinder piston engines faces significant technical bottlenecks: the crankshaft, the core power transmission component, requires manual assembly of various transmission gears to achieve power transmission. This not only increases assembly time and labor costs, but also reduces transmission system reliability. The conventional crankshaft and gear matching structure is prone to wear after long-term operation, seriously affecting the service life of the transmission system. Furthermore, to achieve power output and steering matching, existing technologies typically use a multi-stage gear set between the engine output and the crankshaft gear end. This complex transmission structure not only increases the engine's size and weight, but also reduces transmission efficiency, severely limiting the engine's performance on aircraft. Especially in UAV applications, the contradiction between the demand for engine miniaturization and lightweighting and the requirement for transmission system stability is becoming increasingly prominent. Existing transmission systems also suffer from insufficient vibration absorption capacity, which can easily cause resonance during high-speed operation, leading to reduced gear meshing accuracy and further exacerbating transmission wear. Furthermore, the vibration damping structures in traditional transmission components often utilize a single damping element, making it difficult to adapt to the varying vibration characteristics under varying operating conditions and unable to achieve dynamic vibration damping. To address these issues, existing technologies urgently need improvement. Utility Model Content

[0003] In view of the deficiencies in the prior art, the present invention aims to provide a transmission assembly of an in-line piston engine, an engine and an aircraft thereof.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a transmission assembly of an in-line piston engine, comprising a crankshaft body, wherein the crankshaft body comprises a plurality of crank pins, a plurality of cranks and a plurality of journals arranged in an interlaced manner from the front end to the rear end, a driving gear is integrally formed with the crank at the front end position of the crankshaft body, the center of the driving gear and the journal of the crankshaft body are arranged on the same central axis, a transmission mechanism is provided for external meshing of the driving gear, the transmission mechanism comprises a damping gear assembly, an idler gear and an output gear meshed in sequence, the damping gear assembly is meshed with the driving gear, the damping gear assembly comprises four thin-plate gears arranged coaxially in sequence, a friction plate arranged between adjacent thin-plate gears, and a damping spring arranged on the thin-plate gears and the friction plate, a disc spring is arranged between adjacent thin-plate gears and the friction plate, and all the thin-plate gears, friction plates and disc springs are coaxially arranged , all the thin-plate gears are evenly provided with multiple mounting grooves in the inner circumferential direction, all the mounting grooves on each thin-plate gear correspond to the mounting grooves on other thin-plate gears one by one to form a mounting cavity, each mounting cavity passes through the overall side surface of the shock-absorbing gear assembly, and each mounting cavity passes through the corresponding positions of all friction plate side surfaces, a shock-absorbing spring is provided in each of the mounting cavities along the circumferential direction, and the size of the mounting cavity corresponding to each shock-absorbing spring is adapted to the corresponding shock-absorbing spring, an outer pressure plate covering all the mounting cavities is provided on the outer side surface of the shock-absorbing gear assembly corresponding to one of the outermost thin-plate gears, and an inner bracket is provided on the outer side surface of the shock-absorbing gear corresponding to the other outermost thin-plate gear, the inner bracket is coaxially matched with the center of the shock-absorbing gear shaft hole, and all the thin-plate gears, friction plates, shock-absorbing springs and disc springs are assembled into a whole by fastening bolts after being assembled by the inner bracket and the outer pressure plate.

[0005] In some embodiments, an output shaft is fixedly mounted on the center of the upper shaft of the output gear, and an output flange is provided on one end of the output shaft located outside the crankcase of the engine.

[0006] In some embodiments, a transmission shaft is provided on the shock-absorbing gear assembly, and the shock-absorbing gear assembly is installed at one end of the transmission shaft. An internal spline is provided in the center hole of the inner bracket, and the inner bracket is fixed to the transmission shaft by a key connection. A transmission gear is provided at the other end of the transmission shaft, and the idler gear is engaged with the transmission gear.

[0007] In some embodiments, an idler shaft is integrally provided on the idler wheel, and bearings that are mounted in cooperation with the crankcase of the engine are provided on both sides of the idler shaft corresponding to the idler wheel, on both sides of the output shaft corresponding to the output gear, on both sides of the transmission shaft corresponding to the transmission gear, and on the side of the transmission shaft corresponding to the shock absorber gear assembly away from the transmission gear.

[0008] In some embodiments, the thin-plate gear, friction plate, inner bracket and outer pressure plate each have a plurality of through holes uniformly and concentrically arranged along the circumferential direction, each through hole is penetrated by a fastening bolt, and a rubber sleeve is sleeved on the part of the fastening bolt corresponding to the through hole, and the outer wall of the rubber sleeve is in contact with the inner wall of the through hole.

[0009] In some embodiments, the shock-absorbing springs are divided into two groups according to their shape, size and stiffness coefficient. There is no gap between the two ends of the shock-absorbing springs in the first group and the two end walls of the installation cavity, and there is a gap between the two ends of the shock-absorbing springs in the second group and the two end walls of the installation cavity.

[0010] In some embodiments, the inner surfaces of the inner bracket and the outer pressure plate are symmetrically provided with mounting grooves corresponding to each mounting cavity, which are consistent with the geometric center of the corresponding mounting cavity and match each other in shape and size. The mounting grooves on the inner bracket and the outer pressure plate are divided into two groups according to size, and are matched to install corresponding shock-absorbing springs. There is no gap between the first group of mounting grooves and the end faces of the corresponding shock-absorbing springs, and a gap is provided between the second group of mounting grooves and the end faces of the corresponding shock-absorbing springs. Each pair of mounting grooves on the inner bracket and the outer pressure plate, together with the corresponding mounting cavity, form an enclosed space for installing shock-absorbing springs.

[0011] In some embodiments, the thickness of the tooth body of the thin-plate gear is greater than the thickness of the wheel body, the tooth body side surfaces of adjacent thin-plate gears conflict with each other, and the wheel body side walls between adjacent thin-plate gears form a gap for accommodating the disc spring and the friction plate.

[0012] In order to achieve the above-mentioned purpose, the present invention also provides the following technical solution: an engine adopts the transmission assembly.

[0013] In order to achieve the above-mentioned purpose, the present invention also provides the following technical solution: an aircraft adopting the above-mentioned engine.

[0014] Compared with the prior art, the beneficial effects of the present invention are: through the one-piece molding design of the crankshaft body and the drive gear and the simplification of the transmission mechanism, the manual assembly links are reduced and the risk of gear wear is reduced. At the same time, by optimizing the gear layout and bearing configuration, the overall structural volume is significantly reduced while ensuring the power transmission efficiency, thereby effectively solving the problems of the traditional engine transmission system being complex and bulky, low reliability and difficult to carry on aircraft. It has the advantages of simple and light structure, high assembly efficiency, strong transmission reliability, compact size and easy to carry on aircraft. At the same time, through the coordinated arrangement of the shock-absorbing gear assembly and the shock-absorbing spring, it effectively absorbs the periodic high-frequency vibration load generated by the crankshaft connecting rod mechanism during high-speed operation of the engine, and can also effectively absorb the impact energy brought to the entire engine system during engine start-up and stop, especially during high-load starting or braking. The entire shock-absorbing structure is simple and compact, occupies a small space, and has the advantage of improving the space carrying performance of the aircraft.

[0015] Details of one or more embodiments of the present application are presented in the following drawings and descriptions to make other features, purposes and advantages of the present application more concise and easy to understand, and the present application is fully described and understood through the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the utility model;

[0017] Figure 2 It is a rear view of the utility model;

[0018] Figure 3 It is a structural diagram of the shock-absorbing gear assembly;

[0019] Figure 4 This is a diagram of the internal structure of the shock-absorbing gear assembly after removing the outer pressure plate;

[0020] Figure 5 This is the exploded view of the shock absorber gear assembly;

[0021] Figure 6 This is a structural diagram of the thin-plate gear, friction plate and disc spring after assembly;

[0022] Figure 7 This is a cross-sectional view of the assembled thin-plate gear, friction plate and disc spring;

[0023] Figure 8 for Figure 5 Exploded cross-sectional view of the structure;

[0024] Figure 9 for Figure 6 Main view of the middle structure;

[0025] Figure 10 This is a diagram of the fastening bolt structure.

[0026] In the figure: 1. Crankshaft body; 2. Crank pin; 3. Crank; 4. Journal; 5. Drive gear; 6. Shock absorber gear assembly; 7. Idler; 8. Output gear; 9. Output shaft; 10. Output flange; 11. Drive shaft; 12. Idler shaft; 13. Bearing; 14. Drive gear; 15. Connecting rod piston; 16. Mounting groove; 17. Mounting cavity; 18. Shock absorber spring; 19. Inner bracket; 20. Fastening bolt; 21. Outer pressure plate; 22. Mounting groove; 23. Internal spline; 24. Through hole; 26. Thin-plate gear; 27. Friction plate; 28. Disc spring; 29. ​​Rubber sleeve; 30. Tooth body; 31. Wheel body; 32. Accommodation clearance; 33. High-performance sealed ball bearing. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In the traditional inline four-cylinder piston engine transmission, the crankshaft and transmission gears are assembled separately, requiring manual installation of the drive gear, damper gear assembly, and output gear to different crankshaft sections. This separate gear assembly results in cumulative tolerances on the center axes of the gears, uneven contact stress distribution on the gear meshing surfaces, and periodic shock loads during transmission. The axially stacked layout of the multi-stage gear sets significantly increases the axial space occupied by the transmission system, conflicting with the internal space constraints of the engine crankcase.

[0029] For example, in the power transmission scenario of an in-line four-cylinder piston engine, the drive gear, damper gear assembly, and idler gear assembly need to be installed in sequence at the front end of the crankshaft, and each gear assembly is positioned and installed through an independent journal. During the assembly process, each gear needs to be individually aligned and calibrated. The cumulative assembly error causes the meshing clearance between the drive gear and the damper gear assembly to exceed the design tolerance range. During the operation of the transmission system, the gear meshing surface suffers asymmetric wear due to axial offset, causing fluctuations in the dynamic stiffness of the gear transmission pair. The axial layout length of the gear set reaches 83% of the effective installation space inside the crankcase, forcing the engine casing size to exceed the preset installation boundary of the aircraft power compartment.

[0030] If these issues are not addressed, abnormal wear on the gear meshing surfaces will significantly increase the transmission system's vibration energy in the 800-1200Hz frequency band, inducing resonance between the crankshaft's torsional vibration mode and the gear meshing frequency. The axial space occupied by the multi-stage gear train will force the engine crankcase wall thickness to be reduced to the critical strength value, increasing the risk of fatigue cracking under alternating loads by 47%. Excessive axial dimensions of the transmission system will directly distort the aerodynamic shape of the aircraft's power nacelle, increasing flight drag and reducing payload capacity.

[0031] When faced with the above problems, the present application first analyzes the root causes of axis offset and spatial redundancy caused by traditional split gear assembly, and finds that the separate installation of the crankshaft body and the drive gear is the key factor in the cumulative tolerance. In this regard, the present application considers integrating the drive gear and the crankshaft body into an integrated molding design to eliminate the axis deviation caused by the separate assembly. In response to the gear meshing impact problem, the present application attempts to set a multi-stage shock-absorbing structure between the drive gear and the idler gear, but finds that the multi-stage gear set will aggravate the axial space contradiction. Further research found that by designing the shock-absorbing gear assembly as a superimposed structure of multiple layers of thin-film gears and friction plates, a multi-directional shock-absorbing function can be achieved in a single axial position. In order to solve the problem of installation stability of the shock-absorbing element, the present application adopts a through-type mounting cavity combined with a shock-absorbing spring, and realizes overall packaging through an external pressure plate and an internal bracket to ensure the synchronous movement of each layer of thin-film gears.

[0032] In this regard, Figures 1 to 10As shown, the present application proposes a transmission assembly of an in-line piston engine, including a crankshaft body 1, the crankshaft body 1 includes a plurality of crank pins 2, a plurality of cranks 3 and a plurality of journals 4 arranged in an interlaced manner from the front end to the rear end, a driving gear 5 is integrally formed with the crank 3 at the front end position of the crankshaft body 1, the center of the driving gear 5 is arranged on the same central axis as the journal 4 of the crankshaft body 1, and a transmission mechanism is provided for the external meshing of the driving gear 5, the transmission mechanism includes a damping gear assembly 6, an idler gear 7 and an output gear 8 meshed in sequence, the damping gear assembly 6 is meshed with the driving gear 5, the damping gear assembly 6 includes four thin-plate gears 26 arranged in sequence and coaxially overlapped, a friction plate 27 arranged between adjacent thin-plate gears 26, and a damping spring 18 arranged on the thin-plate gears 26 and the friction plate 27, a disc spring 28 is provided between adjacent thin-plate gears 26 and the friction plate 27, all the thin-plate gears 26, friction plates 27 and disc springs 28 are coaxially arranged, and the inner circumferential direction of all the thin-plate gears 26 is uniform. A plurality of mounting grooves 16 are evenly arranged around, and all the mounting grooves 16 on each thin-plate gear 26 correspond one-to-one to the mounting grooves 16 on other thin-plate gears 26 to form a mounting cavity 17, each mounting cavity 17 passes through the entire side surface of the shock-absorbing gear assembly 6, and each mounting cavity 17 passes through the corresponding positions on the sides of all friction plates 27, and a shock-absorbing spring 18 is arranged in each mounting cavity 17 along the circumferential direction, and the size of the mounting cavity 17 corresponding to each shock-absorbing spring 18 is adapted to the corresponding shock-absorbing spring 18, and an outer pressure plate 21 is provided on the outer side surface of the shock-absorbing gear assembly 6 corresponding to one of the outermost thin-plate gears 26 to cover all the mounting cavities 17, and an inner bracket 19 is provided on the outer side surface of the shock-absorbing gear corresponding to the other outermost thin-plate gear 26, and the inner bracket 19 is coaxially matched with the center of the shock-absorbing gear shaft hole, and all the thin-plate gears 26, friction plates 27, shock-absorbing springs 18 and disc springs 28 are assembled into a whole by fastening bolts 20 after being assembled by the inner bracket 19 and the outer pressure plate 21.

[0033] The crankpin 2 refers to the journal 4 on the crankshaft that connects to the connecting rod. Specifically, it can be forged from high-strength alloy steel and is used to convert the reciprocating motion of the piston into rotational motion of the crankshaft. The crank 3 refers to the curved portion of the crankshaft that connects the crankpin 2 and the journal 4. Specifically, it can be manufactured using an integral molding process, which is used to transmit power and balance rotational inertia. The journal 4 refers to the cylindrical portion of the crankshaft that supports and rotates. Specifically, it can be precision-ground to ensure stable operation of the crankshaft in the bearing. The drive gear 5 is a gear structure integrally molded with the front end of the crankshaft body 1. Specifically, it can be carburized and quenched to enhance tooth surface hardness. It is used to directly transmit the crankshaft power to the transmission mechanism. The damper gear assembly 6 is a multi-layer composite gear structure consisting of a thin-plate gear 26, a friction plate 27, a damper spring 18, and a disc spring 28. Specifically, it can be assembled in an alternating stacking manner. The friction plate 27 and disc spring press-fit structure, together with the damper spring 18, creates a dual damping effect to absorb vibration energy during transmission. The mounting slots 16 are evenly distributed through-grooves on the inner circumference of the thin-plate gear 26, which can be formed using wire cutting. They accommodate the damping spring 18 and achieve synchronous damping between multiple gears. The outer pressure plate 21 is a plate-like structure covering the side of the damping gear assembly 6, which can be secured using bolts to seal the mounting cavity 17 and compress the internal components to maintain structural integrity. The inner bracket 19 is a support component coaxially connected to the damping gear assembly 6, which can be secured to the drive shaft 11 using splines or keyways to ensure coaxiality and stability of power transmission.

[0034] The core innovation of this application lies in the significant simplification of the transmission system's complexity through the integrated design of the crankshaft body 1 and the drive gear 5, as well as the modular assembly structure of the multi-layered damping gear assembly 6. The drive gear 5 is directly integrated into the front end of the crankshaft, eliminating the errors and wear risks associated with traditional split gear assembly. The damping gear assembly 6 achieves efficient vibration damping within a limited space through the stacked combination of thin-plate gears 26, friction plates 27, and springs. The enclosed design of the mounting slots 16 and external pressure plates 21 ensures stable operation of the damping elements. This structure reduces assembly costs while improving the reliability and service life of the transmission system, making it particularly suitable for aircraft engine applications where lightweighting and stability are crucial.

[0035] The operating process and principle of this application are as follows: a crankshaft body 1 is staggered with multiple crankpins 2, multiple cranks 3, and multiple journals 4 arranged in a staggered pattern from the front end to the rear end. A drive gear 5 is integrally formed with the cranks 3 at the front end of the crankshaft body 1, with the center of the drive gear 5 being coaxial with the journals 4 of the crankshaft body 1. The drive gear 5 is externally meshed with a transmission mechanism comprising a damping gear assembly 6, an idler gear 7, and an output gear 8, which mesh with each other in sequence. The damping gear assembly 6 meshes with the drive gear 5.

[0036] The damping gear assembly 6 includes four stacked and coaxially arranged thin-plate gears 26, friction plates 27 disposed between adjacent thin-plate gears 26, and damping springs 18 disposed on the thin-plate gears 26 and friction plates 27. Disc springs 28 are disposed between adjacent thin-plate gears 26 and friction plates 27. All of the thin-plate gears 26, friction plates 27, and disc springs 28 are coaxially arranged.

[0037] Multiple mounting slots 16 are evenly distributed around the inner circumference of all the thin-plate gears 26. Each mounting slot 16 on each thin-plate gear 26 corresponds one-to-one with the mounting slots 16 on other thin-plate gears 26 to form a mounting cavity 17. Each mounting cavity 17 extends through the entire side surface of the damping gear assembly 6 and extends through corresponding locations on the sides of all friction plates 27. A damping spring 18 is circumferentially positioned within each mounting cavity 17, and the size of the mounting cavity 17 corresponding to each damping spring 18 is adapted to the corresponding damping spring 18.

[0038] An outer pressure plate 21 is installed on the outer side of one of the outermost thin-plate gears 26 of the damping gear assembly 6, sealing all mounting cavities 17. An inner bracket 19 is installed on the outer side of the other outermost thin-plate gear 26 of the damping gear assembly 6. The inner bracket 19 is coaxially aligned with the center of the damping gear shaft hole. Fastening bolts 20 secure the inner bracket 19 and outer pressure plate 21 to form a single unit.

[0039] This structural design allows the drive gear 5 to be integrally formed with the crankshaft body 1, eliminating axial misalignment caused by separate assembly. The damping gear assembly 6 utilizes a laminated structure of multiple layers of thin-plate gears 26 and friction plates 27, achieving multi-directional damping within a single axial position. The through-type mounting cavity 17, combined with the design of the damping spring 18 and the integrated packaging of the outer pressure plate 21 and inner bracket 19, ensures the synchronized movement of each layer of thin-plate gears 26 and the stable installation of the damping element.

[0040] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0041] A transmission assembly for an in-line piston engine includes a crankshaft body 1 and a transmission mechanism. The crankshaft body 1 is staggered from front to rear with multiple crankpins 2, multiple cranks 3, and multiple journals 4. At the front end of the crankshaft body 1, a drive gear 5 is integrally formed with the cranks 3. The center of the drive gear 5 is aligned with the central axis of the journals 4 of the crankshaft body 1.

[0042] The transmission mechanism, externally meshed on the drive gear 5, includes a damping gear assembly 6, an idler gear 7, and an output gear 8, which mesh in sequence. The damping gear assembly 6 directly meshes with the drive gear 5. The damping gear assembly 6 consists of four overlapping, coaxially arranged thin-plate gears 26, with friction plates 27 positioned between adjacent thin-plate gears 26. Damping springs 18 are positioned between the thin-plate gears 26 and friction plates 27. Disc springs 28 are also positioned between adjacent thin-plate gears 26 and friction plates 27. All of the thin-plate gears 26, friction plates 27, and disc springs 28 are coaxially arranged.

[0043] Multiple mounting slots 16 are uniformly arranged circumferentially within all the thin-plate gears 26. Each mounting slot 16 on each thin-plate gear 26 corresponds one-to-one with the mounting slots 16 on the other thin-plate gears 26, forming a mounting cavity 17 that extends through the entire side of the damping gear assembly 6. Each mounting cavity 17 extends through corresponding locations on the sides of all friction plates 27. A damping spring 18 is circumferentially positioned within each mounting cavity 17, and the size of the mounting cavity 17 is adapted to the corresponding damping spring 18.

[0044] An external pressure plate 21 is installed on the outer side of the outermost laminar gear 26 on one side of the damping gear assembly 6 to seal all mounting cavities 17. An internal bracket 19 is installed on the outer side of the outermost laminar gear 26 on the other side of the damping gear assembly 6. The internal bracket 19 is coaxially aligned with the center of the damping gear shaft hole. Fastening bolts 20 assemble the laminar gear 26, friction plate 27, damping spring 18, and disc spring 28 into a single unit with the internal bracket 19 and external pressure plate 21.

[0045] Through the above solution, the present application realizes the integrated molding of the crankshaft body 1 and the drive gear 5, eliminating the problems of accumulated tolerance and axis offset caused by separate assembly. The shock-absorbing gear assembly 6 adopts a superimposed structure of multiple layers of thin-plate gears 26 and friction plates 27, realizing a multi-directional shock-absorbing function at a single axial position, effectively alleviating the impact of gear meshing. The through-type mounting cavity 17 is combined with the design of the shock-absorbing spring 18, combined with the overall packaging of the outer pressure plate 21 and the inner bracket 19, to ensure the synchronous movement of each layer of thin-plate gears 26 and the installation stability of the shock-absorbing element. This structural design significantly improves the reliability and service life of the transmission system, while effectively reducing the axial space occupied by the transmission system, making the engine easier to carry on the aircraft.

[0046] The present application further proposes that an output shaft 9 is fixedly mounted on the center of the upper shaft of the output gear 8 , and an output flange 10 is provided on one end of the output shaft 9 located outside the crankcase of the engine.

[0047] The output shaft 9 and output gear 8 are coaxially connected and extend through the crankcase. An output flange 10 is welded or bolted to the end of the output shaft 9. The output shaft 9 and the crankcase are rotatably supported by bearings 13, which are located on the shaft segments on both sides of the output gear 8. The end face of the output flange 10 is equipped with evenly distributed bolt holes for connecting to external load equipment.

[0048] Specifically, the output gear 8 transmits power directly to the coaxially fixed output shaft 9, which is supported on the crankcase by an outer bearing 13, eliminating the structural redundancy caused by multi-stage gear transmission. The output flange 10 is fastened to the external load device via bolts to achieve rigid transmission of power output. This structure reduces vibration caused by assembly errors by eliminating intermediate transmission links. At the same time, the single-stage support design of the output shaft 9 effectively shortens the axial dimension, making the overall engine structure more compact. The standardized interface design of the output flange 10 facilitates rapid docking with the propeller or other loads, improving assembly efficiency.

[0049] As a preferred embodiment, the solution of the present application is specifically implemented as follows: an output shaft 9 is fixedly mounted on the center of the upper shaft of the output gear 8. An output flange 10 is provided on one end of the output shaft 9 located on the outside of the engine crankcase. The output shaft 9 is made of high-strength alloy steel material and has good mechanical properties and wear resistance. The output flange 10 adopts a disc-shaped structure with multiple bolt holes evenly distributed on the outer edge for connection to an external load device. The output flange 10 is fixed to the output shaft 9 by a key connection to ensure the reliability of the transmission. A sealing device is provided at the outer end of the output shaft 9 to prevent leakage of lubricating oil.

[0050] Through the above-described technical solution, this application achieves efficient engine power output. The arrangement of the output shaft 9 and output flange 10 enables convenient connection of the engine to external load devices, expanding the engine's range of applications. Furthermore, the design of the output shaft 9 simplifies the transmission structure, reduces the number of components, and improves transmission efficiency and reliability. The design of the output flange 10 facilitates assembly and disassembly and maintenance, enhancing the practicality of the overall structure.

[0051] The present application further proposes that the bearing on the output shaft 9 located on the side of the output gear 8 close to the output flange 10 is a high-performance sealed ball bearing 33 .

[0052] High-performance sealed ball bearings 33 are ball bearings with a sealed structure, specifically implemented using a combination of inner and outer rings, rolling elements, a cage, and seals. The inner and outer rings can be made of chrome steel or ceramic, and the seals can be made of rubber or metal. Grease is filled between the rolling elements and the raceways. This sealing structure prevents external contaminants from entering the bearing while reducing oil or grease leakage, thereby reducing friction loss and isolating external impurities in the transmission assembly. The sealing structure refers to the enclosing component covering the gap between the inner and outer rings of the bearing. It can employ either a contact or non-contact sealing design, such as a rubber lip seal or a metal dust cover. This structure maintains the bearing's interior clean during high-speed rotation, preventing the intrusion of particulate matter that could lead to increased wear.

[0053] Specifically, a high-performance sealed ball bearing 33 is mounted on the end of the output shaft 9, located outside the crankcase. Its inner and outer races are secured to the inner and outer walls of the crankcase, respectively, supporting the rotation of the output gear 8, output shaft 9, and output flange 10. Lubricant is applied between the bearing's rolling elements and raceways to reduce frictional resistance. The seal also prevents dust and foreign matter from entering the bearing and the crankcase. This design ensures stable operation of the transmission mechanism at high engine speeds while also adapting to the high temperatures and vibrations within the crankcase, reducing the risk of seizures caused by lubrication failure or contamination.

[0054] Through the above technical solution, this application solves the problems of easy contamination and lubrication failure of bearings in traditional engine transmission components, enables the gear transmission mechanism to maintain stable power output under complex working conditions, and reduces the risk of decreased transmission efficiency due to bearing failure, thereby supporting the engine miniaturization design and long-term reliable mounting requirements of aircraft.

[0055] The present application further proposes that the number of teeth of the transmission gear 14 and the idler gear 7 be adjusted according to actual parameter requirements to achieve a change in the total reduction ratio.

[0056] The transmission gear 14 utilizes a gear structure with a customizable tooth count, allowing adjustment to suit different transmission requirements. The idler gear 7, an intermediate gear in the transmission mechanism that meshes with the damper gear assembly 6 and the output gear 8, utilizes a gear structure with a changeable tooth count. By adjusting the tooth count, the speed ratio of the transmission path can be adjusted. The total reduction ratio, defined as the ratio between the input and output speeds of the transmission mechanism, is achieved by adjusting the tooth counts of the transmission gear 14 and the idler gear 7, allowing the engine output characteristics to adapt to varying load conditions.

[0057] Specifically, the number of teeth on the transmission gear 14 and the idler gear 7 is designed to match the actual engine operating parameters. For example, when higher output torque is required, the number of teeth on the transmission gear 14 can be reduced and the number of teeth on the idler gear 7 can be increased, thereby reducing the overall reduction ratio and increasing output torque. When higher speed output is required, the tooth ratio is adjusted in the opposite direction. This flexible configuration of the tooth number combination allows adaptive adjustment of power output without changing the overall layout of the transmission mechanism.

[0058] This solution uses an adjustable tooth number design for the transmission gear 14 and the idler gear 7. The total reduction ratio can be changed by adjusting the tooth number of only two gears, which simplifies the complexity of the transmission chain, reduces the number of parts and assembly links, and reduces the risk of cumulative wear caused by multi-stage gear meshing.

[0059] Through the above technical solution, this application solves the problem of insufficient adaptability of traditional engine transmission components caused by fixed-number gears. Through the design of adjustable number of teeth, flexible matching of reduction ratios is achieved, the number of parts and wear points are reduced, the reliability and maintenance convenience of the transmission system are improved, and the power output requirements under different load conditions are met.

[0060] The present application further proposes that a transmission shaft 11 is provided on the shock-absorbing gear assembly 6, the shock-absorbing gear assembly 6 is installed at one end of the transmission shaft 11, an internal spline 23 is provided in the center hole of the inner bracket 19, the inner bracket 19 is fixedly connected with the transmission shaft 11 by a key, and a transmission gear 14 is provided at the other end of the transmission shaft 11, and the idler gear 7 is meshed with the transmission gear 14.

[0061] One end of the transmission shaft 11 is axially secured to the inner bracket 19 of the damping gear assembly 6 via an internal spline 23. The other end meshes with the idler gear 7 via the transmission gear 14. The internal spline 23 mates with the external spline of the transmission shaft 11 to ensure coaxiality between the damping gear assembly 6 and the transmission shaft 11. The tooth profile parameters of the transmission gear 14 match those of the idler gear 7, forming a stable meshing transmission path. The two ends of the transmission shaft 11 are respectively connected to the damping gear assembly 6 and the transmission gear 14, forming a continuous power transmission channel.

[0062] Specifically, the inner bracket 19 forms a rigid connection with the transmission shaft 11 through the internal spline 23, eliminating the relative displacement between the shock-absorbing gear assembly 6 and the transmission shaft 11, and avoiding the problem of non-concentricity caused by assembly errors. During the meshing process of the transmission gear 14 at the other end of the transmission shaft 11 and the idler gear 7, the contact area between the tooth surface of the transmission gear 14 and the tooth surface of the idler gear 7 is evenly distributed, reducing local stress concentration. The transmission shaft 11 acts as an intermediate carrier, transmitting the power after the shock-absorbing gear assembly 6 absorbs vibration to the transmission gear 14, and then realizing power diversion through the idler gear 7. The matching length of the transmission shaft 11 and the internal spline 23 is designed according to the transmission torque requirement to ensure that the load-bearing capacity of the key connection matches the load of the transmission system.

[0063] As a preferred embodiment, the solution of the present application is specifically implemented as follows: a transmission shaft 11 is provided on the damping gear assembly 6, which is mounted at one end of the transmission shaft 11. An internal spline 23 is provided in the center hole of an inner bracket 19, which is keyed to the transmission shaft 11. A transmission gear 14 is provided at the other end of the transmission shaft 11, and the idler gear 7 meshes with the transmission gear 14. Specifically, the transmission shaft 11 is made of high-strength alloy steel. One end is connected to the inner bracket 19 of the damping gear assembly 6 via an internal spline 23, and the other end is machined into the transmission gear 14. The diameter of the transmission shaft 11 is designed based on the engine power and speed to ensure sufficient strength and rigidity. An internal spline 23 is machined in the center hole of the inner bracket 19 to match the transmission shaft 11, and the inner bracket 19 is keyed to secure the transmission shaft 11. The transmission gear 14 is directly machined at the other end of the transmission shaft 11, and its number of teeth and module are designed based on the transmission ratio requirements with the idler gear 7. The idler wheel 7 is made of high-strength wear-resistant material, and its tooth shape matches the transmission gear 14 to achieve precise meshing between the two.

[0064] Through the above technical solution, the present application realizes a reliable connection between the shock-absorbing gear assembly 6 and the transmission shaft 11, and at the same time completes the power transmission through the meshing of the transmission gear 14 and the idler gear 7. This structural design simplifies the transmission system, reduces the number of parts, and improves the transmission efficiency. Due to the use of an internal spline connection, the connection strength between the shock-absorbing gear assembly 6 and the transmission shaft 11 is enhanced, effectively preventing loosening or falling off that may occur during high-speed operation. In addition, the design of directly processing the transmission gear 14 on the transmission shaft 11 avoids additional installation steps and reduces the difficulty and cost of assembly. Overall, this solution improves the reliability and durability of the transmission system and provides a guarantee for the long-term stable operation of the engine.

[0065] The present application further proposes that an idler shaft 12 is integrally provided on the idler 7, and bearings 13 that are mounted in cooperation with the crankcase of the engine are provided on the idler shaft 12 on both sides corresponding to the idler 7, on both sides of the output shaft 9 corresponding to the output gear 8, on both sides of the transmission shaft 11 corresponding to the transmission gear 14, and on the side of the transmission shaft 11 corresponding to the shock absorber gear assembly 6 away from the transmission gear 14.

[0066] Bearings 13 are positioned on either side of the idler shaft 12 to form a dual-point support structure. Bearings 13 are positioned on either side of the output shaft 9 to provide axial positioning constraints. Bearings 13 are positioned on either side of the drive gear 14 to radially limit the drive shaft 11. Bearings 13 are positioned on the side of the damping gear assembly 6 away from the drive gear 14 to provide cantilever support compensation. Each bearing 13 is a deep groove ball bearing 13 or a tapered roller bearing 13. The inner ring of the bearing 13 has an interference fit with the corresponding journal 4, while the outer ring has a clearance fit with the crankcase bearing 13 seat. The fit tolerance is controlled within the range of 0.02-0.05mm.

[0067] Specifically, the idler shaft 12 is secured to the crankcase sidewall via bearings 13 on either side. The output shaft 9 transmits axial loads via these bearings, while the drive shaft 11 uses these bearings to limit radial runout. The end bearing 13 of the damping gear assembly 6 offsets the cantilever torque generated by gear meshing. The inner ring of the bearing 13 is assembled to the journal 4 using a shrink-fit process, with the assembly temperature controlled between 120-150°C. Molybdenum disulfide grease is applied between the outer ring and the seat of the bearing 13. When the drive shaft 11 transmits torque, the radial load is shared by the bearings 13 on both sides, while the end bearing 13 absorbs axial displacement. The synergistic effect of these bearings 13 maintains constant pressure contact between the gear meshing surfaces, reducing fretting wear on the tooth surfaces and extending the service life of the gear pair.

[0068] As a preferred embodiment, the solution of the present application is specifically implemented as follows: an idler shaft 12 is integrally provided on the idler 7. Bearings 13 are provided on the idler shaft 12 on both sides corresponding to the idler 7 and are mounted in cooperation with the engine's crankcase. Bearings 13 are provided on the output shaft 9 on both sides corresponding to the output gear 8 and are mounted in cooperation with the engine's crankcase. Bearings 13 are provided on the transmission shaft 11 on both sides corresponding to the transmission gear 14 and are mounted in cooperation with the engine's crankcase. Bearings 13 are provided on the transmission shaft 11 on the side of the damping gear assembly 6 away from the transmission gear 14 and are mounted in cooperation with the engine's crankcase.

[0069] Through the above-mentioned technical solution, the present application achieves effective support and positioning of various components of the transmission assembly. By disposing bearings 13 at key locations on the idler shaft 12, output shaft 9, and drive shaft 11, the operational stability and precision of the transmission system are improved. The rational arrangement of the bearings reduces friction losses during the transmission process and extends the service life of various transmission components. Furthermore, the coordinated installation method of the bearings and the crankcase simplifies the assembly process and facilitates maintenance and replacement. This bearing arrangement effectively solves the problems of insufficient support and unstable operation present in traditional in-line piston engine transmission systems, ensuring the long-term and reliable operation of the engine.

[0070] The present application further proposes that the thin-plate gear 26, the friction plate 27, the inner bracket 19 and the outer pressure plate 21 each have multiple through holes 24 uniformly and concentrically arranged along the circumferential direction, and a fastening bolt 20 is arranged through each through hole 24. A rubber sleeve 29 is sleeved on the part of the fastening bolt 20 corresponding to the through hole 24, and the outer wall of the rubber sleeve 29 is in conflict with the inner wall of the through hole 24.

[0071] The through-holes 24 form evenly distributed channels circumferentially through the thin-plate gear 26, friction plate 27, inner bracket 19, and outer pressure plate 21, with the axes of the through-holes 24 in each component aligned. The rubber sleeve 29 is made of an elastic material, and its outer diameter forms an interference fit with the inner diameter of the through-hole 24. When the fastening bolt 20 passes through the through-hole 24, the rubber sleeve 29 is compressed to fill the annular gap between the bolt shank and the inner wall of the through-hole 24.

[0072] Specifically, when the damping gear assembly 6 is subjected to the periodic torque transmitted by the crankshaft, the relative movement between the thin-plate gear 26 and the friction plate 27 is buffered by the disc spring 28, but the vibration of the assembly structure will still be transmitted to the fastening bolt 20. The rubber sleeve 29 absorbs the vibration energy between the bolt and the through hole 24 through elastic deformation, reducing direct contact between metal parts. The radial compression force of the rubber sleeve 29 forms a flexible support for the bolt rod in the through hole 24, avoiding a rigid collision between the bolt rod and the inner wall of the through hole 24. While maintaining assembly accuracy, this structure suppresses the vibration transmission path through the damping properties of the elastic material, effectively preventing the attenuation of the bolt preload. Experimental data show that after 200 hours of continuous operation of the damping gear assembly 6 using this structure, the axial preload retention rate of the fastening bolt 20 can reach more than 92% of the initial value.

[0073] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0074] The thin-plate gear 26, friction plate 27, inner bracket 19, and outer pressure plate 21 each have multiple through-holes 24 uniformly and concentrically disposed therethrough along the circumference. A fastening bolt 20 is inserted through each through-hole 24. A rubber sleeve 29 is sleeved over the portion of the fastening bolt 20 corresponding to the portion within the through-hole 24. The outer wall of the rubber sleeve 29 abuts against the inner wall of the through-hole 24.

[0075] Specifically, the thin-plate gear 26, friction plate 27, inner bracket 19, and outer pressure plate 21 are all disc-shaped. Multiple through-holes 24 are evenly distributed along the circumference of each disc. These through-holes 24 correspond to each other on the various components. The rubber sleeve 29 can be made of nitrile rubber, which has excellent elasticity and sealing properties.

[0076] Through the above-described technical solution, the present application achieves reliable connection and fixation of the various components of the shock-absorbing gear assembly 6. The use of the rubber sleeve 29 effectively reduces metal contact between the fastening bolt 20 and the inner wall of the through-hole 24, thereby reducing vibration transmission. Furthermore, the elastic deformation of the rubber sleeve 29 absorbs some vibration energy, further enhancing the shock-absorbing effect. Furthermore, the tight fit of the rubber sleeve 29 against the inner wall of the through-hole 24 prevents the ingress of dust and impurities, thereby extending the service life of the shock-absorbing gear assembly 6.

[0077] The present application further proposes that the shock-absorbing springs 18 are divided into two groups according to their shape, size and stiffness coefficient. There is no gap between the two ends of the shock-absorbing springs 18 of the first group and the two end walls of the installation cavity 17, and there is a gap between the two ends of the shock-absorbing springs 18 of the second group and the two end walls of the installation cavity 17.

[0078] The first set of damping springs 18 are installed without gaps to directly transmit high-frequency, low-amplitude vibrations. The second set of damping springs 18 have gaps to allow for elastic deformation under low-frequency, high-amplitude vibrations. The difference in stiffness between the two sets of springs, adjusted in shape and size, ensures that vibration energy of different frequencies is absorbed in a graded manner. The disc springs 28 between the thin-plate gear 26 and the friction plate 27 further coordinately regulate axial pressure, preventing excessive wear of the friction plate 27 due to vibration impact.

[0079] Specifically, when the engine generates high-frequency vibrations, the first set of damping springs 18, due to their gap-free mounting, quickly responds and absorbs energy, reducing gear meshing shock. Under low-frequency, high-amplitude vibrations, the second set of damping springs 18 compress and deform within the gap, extending the vibration decay time. The difference in stiffness between the two sets of springs is achieved through their shape and dimensions. For example, the first set uses coil springs with a larger wire diameter, while the second set uses variable-pitch springs with a smaller wire diameter. The dimensions of the mounting cavity 17 match the outer diameter of the corresponding spring, ensuring that the springs do not deflect radially during compression. The disc springs 28 provide preload between the disc gear 26 and the friction plate 27, ensuring that the friction plate 27 maintains stable contact pressure during vibration, preventing slippage or excessive wear.

[0080] As a preferred embodiment, the solution of the present application is specifically implemented as follows: the shock-absorbing springs 18 are divided into two groups according to their shape, size and stiffness coefficient. There is no gap between the two ends of the first group of shock-absorbing springs 18 and the two end walls of the installation cavity 17. Gaps are set between the two ends of the second group of shock-absorbing springs 18 and the two end walls of the installation cavity 17. Specifically, the first group of shock-absorbing springs 18 can adopt cylindrical springs, whose outer diameter matches the inner diameter of the installation cavity 17 and whose length is equal to the length of the installation cavity 17. The second group of shock-absorbing springs 18 can adopt conical springs, whose maximum outer diameter matches the inner diameter of the installation cavity 17 and whose length is less than the length of the installation cavity 17. Therefore, during installation, the first group of shock-absorbing springs 18 can be directly installed in the corresponding installation cavity 17, while after the second group of shock-absorbing springs 18 are installed in the corresponding installation cavity 17, a certain gap will be left between the two ends and the end walls of the installation cavity 17.

[0081] Through the above technical solution, the present application can achieve a graded shock-absorbing effect for the shock-absorbing gear assembly 6. The first group of shock-absorbing springs 18 are always in a stressed state during the gear transmission process, and can continuously absorb small-amplitude vibrations. The second group of shock-absorbing springs 18 will only be stressed and deformed when large vibrations occur during the gear transmission process, and can buffer large-amplitude instantaneous impacts. This graded shock-absorbing structure can effectively reduce vibration and noise during the gear transmission process and improve the stability and reliability of the transmission system. At the same time, due to the use of springs of different shapes and stiffness, a wider range of shock-absorbing effects can be achieved within a limited installation space, which is conducive to reducing the overall size of the shock-absorbing gear assembly 6.

[0082] The present application further proposes that on the inner surfaces of the inner bracket 19 and the outer pressure plate 21, corresponding to each mounting cavity 17, there are symmetrically arranged mounting grooves 22 that are consistent with the geometric center of the corresponding mounting cavity 17 and match each other in shape and size. The mounting grooves 22 on the inner bracket 19 and the outer pressure plate 21 are divided into two groups according to size, and are respectively matched to install the corresponding shock-absorbing springs 18. There is no gap between the first group of mounting grooves 22 and the end faces of the corresponding shock-absorbing springs 18, and a gap is set between the second group of mounting grooves 22 and the end faces of the corresponding shock-absorbing springs 18. Each pair of mounting grooves 22 on the inner bracket 19 and the outer pressure plate 21, together with the corresponding mounting cavity 17, form an enclosed space for installing the shock-absorbing spring 18.

[0083] Among them, the geometric center of the mounting groove 22 coincides with the axis of the mounting cavity 17, ensuring that the installation position of the shock-absorbing spring 18 is coaxial with the overall assembly; the mounting grooves 22 are divided into two groups, the size of the first group of mounting grooves 22 is completely in line with the end face of the shock-absorbing spring 18, and the size of the second group of mounting grooves 22 is slightly larger than the end face of the shock-absorbing spring 18, forming a gap; the mounting grooves 22 and the mounting cavity 17 cooperate to form an annular enclosed space, covering the axial ends of the shock-absorbing spring 18.

[0084] Specifically, the shock-absorbing spring 18 is constrained in a closed space formed by the mounting cavity 17 and the mounting slot 22. The first group of shock-absorbing springs 18 are rigidly fixed by the gapless mounting slot 22, and the second group of shock-absorbing springs 18 are allowed to have slight axial displacement by the gap mounting slot 22. The symmetrical distribution of the mounting slot 22 makes the force direction of the shock-absorbing spring 18 consistent with the rotation direction of the component, avoiding unbalanced load. The closed space isolates the external vibration transmission path and limits the radial displacement of the shock-absorbing spring 18 during high-speed operation. The size grouping of the mounting slot 22 matches the shock-absorbing spring 18 with different stiffness coefficients. The first group of mounting slots 22 corresponds to high-stiffness springs to suppress high-frequency vibrations, and the second group of mounting slots 22 corresponds to low-stiffness springs to absorb low-frequency impacts. The inner bracket 19 and the mounting slot 22 of the outer pressure plate 21 form an axial limiting structure, so that the pressure on the overlapping surface of the multi-layer thin-plate gear 26 and the friction plate 27 is evenly distributed, reducing the risk of unbalanced wear of the disc spring 28.

[0085] As a preferred embodiment, the solution of this application is specifically implemented as follows:

[0086] On the inner surfaces of the inner bracket 19 and the outer pressure plate 21, corresponding to each mounting cavity 17, there are symmetrically provided mounting grooves 22 that are consistent with the geometric center of the corresponding mounting cavity 17 and have matching shapes and sizes. The mounting grooves 22 on the inner bracket 19 and the outer pressure plate 21 are divided into two groups according to size, and are respectively matched to install the corresponding shock-absorbing springs 18. There is no gap between the first group of mounting grooves 22 and the end faces of the corresponding shock-absorbing springs 18. A gap is provided between the second group of mounting grooves 22 and the end faces of the corresponding shock-absorbing springs 18. Each pair of mounting grooves 22 on the inner bracket 19 and the outer pressure plate 21, together with the corresponding mounting cavity 17, form an enclosed space for installing the shock-absorbing spring 18.

[0087] Specifically, a plurality of mounting grooves 22 are provided on the inner surfaces of the inner bracket 19 and the outer pressure plate 21. These mounting grooves 22 are distributed in a circular array on the inner surfaces of the inner bracket 19 and the outer pressure plate 21, and the position of each mounting groove 22 corresponds to the position of the corresponding mounting cavity 17. The shape of the mounting groove 22 can be cylindrical, elliptical or other shapes suitable for the installation of the shock-absorbing spring 18. The size of the first group of mounting grooves 22 completely matches the size of the corresponding shock-absorbing spring 18, so that the end face of the shock-absorbing spring 18 fits tightly with the bottom surface of the mounting groove 22 after the shock-absorbing spring 18 is installed. The size of the second group of mounting grooves 22 is slightly larger than the size of the corresponding shock-absorbing spring 18. After the shock-absorbing spring 18 is installed, a preset gap is left between its end face and the bottom surface of the mounting groove 22.

[0088] Thus, when the inner bracket 19 and outer pressure plate 21 are assembled with the thin-plate gear 26, each pair of opposing mounting slots 22 and the corresponding mounting cavity 17 form a closed space for accommodating and securing the shock-absorbing spring 18. This structural design allows the shock-absorbing spring 18 to freely compress and release within the predetermined space, effectively absorbing and cushioning the vibration and impact generated during transmission.

[0089] Through the above-described technical solution, the present application achieves precise positioning and effective fixation of the shock-absorbing spring 18. By providing two sets of mounting slots 22 of different sizes, targeted shock-absorbing designs can be implemented based on the vibration characteristics under different operating conditions, improving the flexibility and adaptability of the shock-absorbing effect. Furthermore, the enclosed installation space prevents the shock-absorbing spring 18 from shifting and falling off during long-term use, thereby improving the reliability and durability of the transmission assembly. Furthermore, this structural design simplifies the installation process of the shock-absorbing spring 18, facilitates assembly and maintenance, and contributes to improving production efficiency and reducing maintenance costs.

[0090] The present application further proposes that the thickness of the tooth body portion 30 of the thin-plate gear 26 is greater than the thickness of the wheel body portion 31, the side surfaces of the tooth body portions 30 between adjacent thin-plate gears 26 conflict with each other, and the side walls of the wheel body portion 31 between adjacent thin-plate gears 26 form a gap for accommodating the disc spring 28 and the friction plate 27.

[0091] The thickness of the tooth body 30 is set to be greater than that of the wheel body 31, so that the side surfaces of the tooth bodies 30 of adjacent thin-plate gears 26 form a rigid contact surface after assembly, while a predetermined gap is maintained between the side walls of the wheel body 31. The axial dimension of this gap is determined by the thickness difference of the wheel body 31, and its width matches the thickness of the disc spring 28 and friction plate 27. The contact area on the side surfaces of the tooth body 30 is continuously distributed along the circumference, forming a stable force transmission path.

[0092] Specifically, during operation of the transmission assembly, the radial load generated by gear meshing is directly transmitted to the adjacent thin-plate gear 26 through the contact surface of the tooth body 30, preventing the load from acting on the friction plate 27 and disc spring 28 within the gap of the wheel body 31. The disc spring 28, located within the gap of the wheel body 31, elastically deforms when subjected to axial pressure, dissipating vibration energy through sliding friction between the friction plate 27 and the wheel body 31 of the thin-plate gear 26. The thickened tooth body 30 design increases the load-bearing capacity of the contact surface, while the gap formed by the thinning of the wheel body 31 provides precise installation space for the shock-absorbing element, ensuring that the compression stroke of the disc spring 28 and the relative displacement of the friction plate 27 are controlled within the designed range, thereby optimizing vibration attenuation and extending the service life of the assembly.

[0093] As a preferred embodiment, the solution of this application is specifically implemented as follows: the tooth body 30 of the thin-slice gear 26 is machined into a stepped structure with a thickness greater than that of the wheel body 31. When the four thin-slice gears 26 are stacked axially, the side faces of the tooth bodies 30 of adjacent thin-slice gears 26 achieve end-to-end contact through the stepped structure, forming an annular gap between the sidewalls of the wheel body 31. Within this annular gap, the friction plate 27 is arranged parallel to the sidewalls of the wheel body 31. Two disc springs 28 are respectively sandwiched between the two side surfaces of the friction plate 27 and the sidewalls of the wheel body 31, with the convex surfaces of the disc springs 28 facing toward the friction plate 27.

[0094] Through the above-mentioned technical solution, the present application achieves a layered damping function for the thin-plate gear 26 assembly: the end faces of the tooth body 30 contact to form a rigid support layer to maintain the stability of the gear transmission, while the disc spring 28 and friction plate 27, located within the gap of the wheel body 31, form a flexible buffer layer, effectively absorbing high-frequency vibration energy during transmission. This rigid-flexible composite structure not only ensures transmission accuracy, but also converts vibration energy into heat energy through the synergistic action of the friction plate 27 and disc spring 28, thereby avoiding the stress concentration phenomenon of traditional rigid gear assemblies and significantly extending the service life of the damping gear assembly 6.

[0095] The present application further proposes an engine, which adopts a transmission assembly including a crankshaft body 1, a drive gear 5, and a transmission mechanism. The front end of the crankshaft body 1 and the crank 3 are integrally formed with the drive gear 5, and the drive gear 5 is meshed with the shock absorber gear assembly 6, the idler gear 7, and the output gear 8 in sequence. The axes of multiple shaft necks 4 coincide, the crank pin 2 is eccentrically set, and the crank 3 is provided with a counterweight block.

[0096] Among them, the transmission assembly refers to a mechanical structure for transmitting power, which can be specifically realized by combining the crankshaft body 1 with a gear set. The crankshaft body 1 transmits power to the damping gear assembly 6 through the drive gear 5, and then transmits it to the output gear 8 through the transmission gear 14 and the idler gear 7, thereby simplifying the transmission path. Among them, the drive gear 5 refers to a gear structure integrally formed with the crankshaft body 1. Specifically, it can be processed synchronously with the crankshaft using a forging or casting process to avoid assembly errors and wear problems caused by the installation of split gears. Among them, the damping gear assembly 6 refers to a gear assembly with a buffering function. Specifically, a damping spring 18 can be set inside the gear assembly or a rubber damping layer can be set on the outer surface of the gear to absorb the vibration transmitted by the crankshaft and reduce the transmission impact. Among them, the idler gear 7 refers to an intermediate gear used to change the transmission direction and speed. Specifically, a steel gear with a single tooth surface hardening treatment can be used to reduce the number of gears and maintain the transmission direction matching requirements.

[0097] Specifically, the crankshaft body 1 directly meshes with the damping gear assembly 6 via the front drive gear 5. Power is transmitted to the output gear 8 via the drive gear 14 and the idler gear 7, which then rotates the output shaft 9. The meshing of the damping gear assembly 6, the drive gear 14, and the idler gear 7 in the transmission mechanism replaces a traditional multi-stage gear set, reducing the number of gears and the number of mounting points. The crankshaft and drive gear 5 are integrally formed, eliminating separate assembly steps and minimizing the risk of manual intervention and wear.

[0098] This solution replaces the original clutch mechanism with a damping gear assembly 6, and adds a simple idler gear 7 to replace the original idler shaft 12 mechanism, reducing the number of parts and simplifying the power transmission path, avoiding the space occupation and efficiency loss caused by the existing multi-stage gear and clutch mechanism.

[0099] Through the above technical solution, this application solves the problems of low assembly efficiency and severe wear caused by the separate installation of crankshaft gears, simplifies the transmission structure and improves the stability of power transmission, adapts to the needs of engine miniaturization, and meets the aircraft's requirements for a compact power system.

[0100] The present application further proposes an aircraft that uses an engine including an in-line piston engine transmission assembly, wherein the transmission assembly has an integrated crankshaft body 1, a damping gear assembly 6 and a multi-stage meshing transmission mechanism.

[0101] The engine's crankshaft body 1 has an integrally formed drive gear 5 at the front end, which meshes with a damper gear assembly 6. The damper gear assembly 6 is composed of four laminated gears 26, friction plates 27, damper springs 18, and disc springs 28. Multiple mounting slots 16 are provided within the laminated gears 26, forming a through-mounted mounting cavity 17. The damper springs 18 are positioned within the mounting cavity 17. The laminated gears 26, friction plates 27, and disc springs 28 are secured to an inner bracket 19 via an outer pressure plate 21, forming a single unit. The damper gear assembly 6 is connected to an idler gear 7 via a drive shaft 11. The idler gear 7 meshes with an output gear 8, which in turn secures the output shaft 9 and flange. The tooth bodies 30 of the laminated gears 26 are thicker than the gear bodies 31. Adjacent tooth bodies 30 contact each other, creating a gap to accommodate the disc springs 28. A disc spring 28 is positioned between the friction plates 27 and the laminated gears 26. The inner bracket 19 and the outer pressure plate 21 are provided with a mounting groove 22 , and the mounting groove 22 and the mounting cavity 17 together form a closed space, and a gap is retained between part of the mounting groove 22 and the end surface of the shock-absorbing spring 18 .

[0102] Specifically, when the aircraft engine is operating, the crankshaft body 1 transmits power to the damping gear assembly 6 via the drive gear 5. The four thin-plate gears 26 undergo relative displacement during the power transmission process, and the friction plate 27 and disc spring 28 absorb vibration energy. The damping spring 18 within the mounting cavity 17 further buffers torque fluctuations through compression deformation. The tooth bodies 30 of adjacent thin-plate gears 26 directly contact each other to form a rigid support, while the disc spring 28 within the gap between the wheel body 31 provides elastic damping. The multi-stage damping structure synergistically reduces the vibration amplitude of the transmission system. The power output by the damping gear assembly 6 is transmitted to the idler gear 7 via the transmission shaft 11. The idler gear 7 changes the transmission direction and drives the output gear 8. The output flange 10 transmits the power to the aircraft propeller. The clearance between the mounting slot 22 of the inner bracket 19 and the outer pressure plate 21 and the end face of the damping spring 18 allows the spring to deform freely under specific loads, avoiding stress concentration caused by rigid constraints. The laminated structure of the thin-plate gear 26 and friction plate 27 uses the preload of the fastening bolts 20 to control the contact pressure on the friction surfaces, dissipating vibration energy at the interface between the different materials. This integrated transmission assembly maintains power transmission efficiency while integrating a multi-stage damping unit within a limited space through structural optimization, enabling the inline engine to meet the dual requirements of compact aircraft layout and high reliability.

[0103] As a preferred embodiment, the solution of the present application is specifically implemented as follows: an in-line piston engine is installed in the aircraft's engine compartment, an output shaft 9 extending from the outside of the engine's crankcase, the end of which is equipped with an output flange 10 for connection to a propeller. A transmission assembly is integrated within the engine, wherein the front end of the crankshaft forms a meshing transmission with a damping gear assembly 6 through an integrally formed drive gear 5. The damping gear assembly 6 is composed of four layers of thin-plate gears 26 alternately stacked by disc springs 28 and friction plates 27. The mounting grooves 16 of each layer of gears are embedded with damping springs 18 and are press-fitted to the inner bracket 19 via an outer pressure plate 21. The transmission path is transmitted through the damping gear assembly 6 to the idler gear 7, and ultimately drives the output shaft 9 to rotate through the output gear 8, wherein both ends of the shaft of each transmission gear 14 are supported by bearings on the crankcase.

[0104] Through the above-mentioned technical solution, this application effectively solves the complex assembly issues of multi-stage gear sets in traditional in-line engines for UAV applications. By combining the integrally formed drive gear 5 with the integrated damping gear assembly 6, manual assembly steps are reduced. The multi-layered sheet structure of the damping gear assembly 6, combined with the disc springs 28 and friction plates 27, buffers transmission shock while maintaining a compact layout, thus preventing gear wear caused by long-term operation. This structure shortens the overall axial length of the engine, meeting the aircraft's requirements for lightweight and miniaturized power systems. Transmission efficiency is significantly improved, thereby enhancing the aircraft's endurance and payload.

[0105] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

[0106] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A transmission assembly of an in-line piston engine, comprising a crankshaft body (1), characterized in that: The crankshaft body (1) comprises a plurality of crank pins (2), a plurality of cranks (3) and a plurality of journals (4) arranged in an interlaced manner from the front end to the rear end. A driving gear (5) is provided at the front end of the crankshaft body (1) and is integrally formed with the crank (3). The center of the driving gear (5) and the journal (4) of the crankshaft body (1) are arranged on the same central axis. A transmission mechanism is provided on the outside of the driving gear (5). The transmission mechanism comprises a damping gear assembly (6), an idler gear (7) and an output gear (8) that are meshed in sequence. The damping gear assembly (6) and the driving gear ( 5) meshing, the damping gear assembly (6) includes four thin-plate gears (26) stacked in sequence and arranged on the same axis, friction plates (27) arranged between adjacent thin-plate gears (26), and damping springs (18) arranged on the thin-plate gears (26) and the friction plates (27), and disc springs (28) are arranged between adjacent thin-plate gears (26) and the friction plates (27). All the thin-plate gears (26), friction plates (27) and disc springs (28) are arranged coaxially, and all the thin-plate gears (26) are uniformly provided with a plurality of mounting grooves (1 6), all the mounting grooves (16) on each thin-plate gear (26) correspond one-to-one with the mounting grooves (16) on other thin-plate gears (26) to form mounting cavities (17), each mounting cavity (17) passes through the entire side surface of the damping gear assembly (6), and each mounting cavity (17) passes through the corresponding position of the side surface of all friction plates (27), each of the mounting cavities (17) is provided with a damping spring (18) along the circumferential direction, and the size of the mounting cavity (17) corresponding to each damping spring (18) is adapted to the corresponding damping spring (18), An outer pressure plate (21) for sealing all mounting cavities (17) is provided on the outer side surface of the shock-absorbing gear assembly (6) corresponding to one of the outermost thin-plate gears (26), and an inner bracket (19) is provided on the outer side surface of the shock-absorbing gear corresponding to the other outermost thin-plate gear (26). The inner bracket (19) is coaxially matched with the center of the shock-absorbing gear shaft hole. All the thin-plate gears (26), friction plates (27), shock-absorbing springs (18) and disc springs (28) are assembled into a whole by the inner bracket (19) and the outer pressure plate (21) and then assembled into a whole by fastening bolts (20).

2. The transmission assembly of an in-line piston engine according to claim 1, characterized in that: An output shaft (9) is fixedly mounted on the center of the upper shaft of the output gear (8), and an output flange (10) is provided on one end of the output shaft (9) located outside the crankcase of the engine.

3. The transmission assembly of an in-line piston engine according to claim 2, characterized in that: A transmission shaft (11) is provided on the damping gear assembly (6), and the damping gear assembly (6) is mounted on one end of the transmission shaft (11). An internal spline (23) is provided in the center hole of the inner bracket (19), and the inner bracket (19) and the transmission shaft (11) are fixedly connected by a key. A transmission gear (14) is provided on the other end of the transmission shaft (11), and the idler gear (7) is meshed with the transmission gear (14).

4. The transmission assembly of an in-line piston engine according to claim 3, characterized in that: An idler shaft (12) is integrally provided on the idler wheel (7), and bearings (13) are provided on the idler shaft (12) on both sides corresponding to the idler wheel (7), on both sides of the output shaft (9) corresponding to the output gear (8), on both sides of the transmission shaft (11) corresponding to the transmission gear (14), and on one side of the transmission shaft (11) corresponding to the damping gear assembly (6) away from the transmission gear (14), and are mounted in cooperation with the crankcase of the engine.

5. The transmission assembly of an in-line piston engine according to claim 4, characterized in that: The thin-plate gear (26), friction plate (27), inner bracket (19) and outer pressure plate (21) are each uniformly circumferentially and concentrically provided with a plurality of through holes (24), each through hole (24) is provided with a fastening bolt (20), and a rubber sleeve (29) is sleeved on the portion of the fastening bolt (20) corresponding to the through hole (24), and the outer wall of the rubber sleeve (29) is in contact with the inner wall of the through hole (24).

6. The transmission assembly of an in-line piston engine according to claim 1, characterized in that: The shock absorbing springs (18) are divided into two groups according to their shape, size and stiffness coefficient. There is no gap between the two ends of the shock absorbing springs (18) of the first group and the two end walls of the installation cavity (17), and there is a gap between the two ends of the shock absorbing springs (18) of the second group and the two end walls of the installation cavity (17).

7. The transmission assembly of an in-line piston engine according to claim 6, characterized in that: On the inner surfaces of the inner bracket (19) and the outer pressure plate (21), corresponding to each mounting cavity (17), there are symmetrically provided mounting grooves (22) which are consistent with the geometric center of the corresponding mounting cavity (17) and have matching shapes and sizes. The mounting grooves (22) on the inner bracket (19) and the outer pressure plate (21) are divided into two groups according to size, and are respectively matched to install the corresponding shock-absorbing springs (18). There is no gap between the first group of mounting grooves (22) and the end surface of the corresponding shock-absorbing spring (18), and a gap is provided between the second group of mounting grooves (22) and the end surface of the corresponding shock-absorbing spring (18). Each pair of mounting grooves (22) on the inner bracket (19) and the outer pressure plate (21) and the corresponding mounting cavity (17) together form a closed space for installing the shock-absorbing spring (18).

8. The transmission assembly of an in-line piston engine according to claim 1, characterized in that: The thickness of the tooth body portion (30) of the thin-plate gear (26) is greater than the thickness of the wheel body portion (31), the side surfaces of the tooth body portions (30) between adjacent thin-plate gears (26) abut against each other, and the side walls of the wheel body portions (31) between adjacent thin-plate gears (26) form a gap for accommodating the disc spring (28) and the friction plate (27).

9. An engine, characterized in that: A transmission assembly according to any one of claims 1 to 8 is used.

10. An aircraft, characterized in that: The engine according to claim 9 is used.

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