A light helicopter transmission device driven by a synchronous belt

Abstract

The present invention belongs to the technical field of helicopter transmissions and discloses a light helicopter transmission device driven by a synchronous belt, comprising a main reducer, an upper pulley, a tension adjustment assembly, a tail drive shaft assembly, a tail reducer, a clutch assembly, and a synchronous belt. The engine power and speed are connected to the clutch assembly, and the outer side of the clutch assembly is a lower pulley connected to the synchronous belt. When the speed of the clutch assembly reaches a certain value, the lower pulley rotates with the clutch assembly under the action of the clutch. The other side of the synchronous belt is connected to the upper pulley, one axial end of the upper pulley engages with the main reducer to transmit motion to the main rotor, and the other axial end of the upper pulley transmits motion to the tail reducer via the tail drive shaft assembly. A tension adjustment assembly is provided between the ends of the lower pulley and the upper pulley. The present invention can keep the synchronous belt in a normally tensioned working state, significantly reduce the influence of piston engine vibration on the tension of the synchronous belt, and improve the rotation stability and service life of the synchronous belt.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter transmission, and relates to a transmission device of a light helicopter, in particular to a light helicopter transmission device driven by a synchronous belt. Background Art

[0002] Light helicopters typically use low-speed aviation piston engines, which have low output speeds and significant piston vibration in the reciprocating direction. Furthermore, piston engines have difficulty starting under load. To address these challenges, conventional UAV transmission systems have employed synchronous belt drives (ZL201520275493.X, "A Self-Tensioning Belt Drive with a Fixed Center Distance"). A centrifugal clutch is designed to control the connection and disconnection between the piston engine and the transmission. A complex bracket structure and spring self-tensioning mechanism are designed between the synchronous belt pulleys to adjust the tension of the synchronous belt. The centrifugal clutch is connected to the pulleys via a drum spline shaft or a double-diaphragm shaft. The centrifugal clutch compensates for the deflection of the engine output axis caused by large engine displacement vibrations by floating the drum spline shaft or deforming the diaphragm coupling. This synchronous belt drive mechanism is complex and heavy. The large deflection compensation angle of the drum spline shaft or diaphragm coupling caused by engine vibration significantly reduces the fatigue life of the connecting components between the engine and the transmission system, increasing the operating and maintenance costs of the helicopter. Furthermore, the high-frequency vibration excitation of the engine can affect other moving components in the transmission system, reducing their fatigue life.

[0003] Patent CN201210188899.5 "A Small Unmanned Helicopter Fuselage" introduces a transmission configuration with a synchronous belt and a centrifugal clutch. Power is transmitted to the synchronous belt through the centrifugal clutch, and then transmitted to the gearbox and main rotor shaft through the synchronous belt, and then transmitted to the tail shaft through the second synchronous belt. This configuration is complex and requires two synchronous belts to complete the main rotor and tail rotor drive. A centrifugal clutch is designed between the pulleys connected to the engine, resulting in the pulley cantilever that bears the tension being too long, insufficient support rigidity, and a lack of an effective adjustment mechanism between the upper and lower pulleys. As a result, the tension of the upper and lower pulleys changes due to engine vibration, which may cause the synchronous belt to slip or be damaged, reducing the life of the synchronous belt. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a light helicopter transmission device driven by a synchronous belt, which not only solves the problem of starting a piston engine under load, but also reduces the vibration of the start-up and isolates the engine vibration from being transmitted to the transmission device, thereby improving the fatigue life and overhaul interval of the moving parts. At the same time, it eliminates the drum-type spline shaft or double-diaphragm shaft, reducing the use and maintenance costs of the helicopter. Its structure is streamlined, light in weight, safe and reliable, and the present invention is suitable for light helicopters.

[0005] The technical solutions of the present invention are as follows:

[0006] A light helicopter transmission device driven by a synchronous belt comprises a main reducer, an upper pulley, a tension adjustment assembly, a tail transmission shaft assembly, a tail speed reducer, a clutch assembly and a synchronous belt; the engine power and speed are connected to the clutch assembly, the outer side of the clutch assembly is a lower pulley, and the lower pulley is connected to the synchronous belt. When the speed of the clutch assembly reaches a certain value, the lower pulley rotates with the inside of the clutch assembly under the action of the clutch; the other side of the synchronous belt is connected to the upper pulley, one axial end of the upper pulley is engaged with the main speed reducer to transmit motion to the main rotor, and the other axial end of the upper pulley is transmitted to the tail speed reducer via the tail transmission shaft assembly; a tension adjustment assembly is provided between the end of the lower pulley and the end of the upper pulley.

[0007] Furthermore, the engine is flexibly installed below the main reducer.

[0008] Furthermore, one end of the upper pulley meshing with the main reducer is a bevel gear, and the lower end of the main reducer is a first-stage bevel gear. The bevel gear of the upper pulley meshes with the first-stage bevel gear of the main reducer, and the rotation direction is reversed.

[0009] Furthermore, the other end of the upper pulley is an axially extending tail drive shaft assembly, which is a long shaft. The other end of the tail drive shaft assembly is a bevel gear, and the bevel gear of the tail drive shaft assembly is reduced and reversed by the first-stage bevel gear of the tail reducer and transmitted to the tail rotor installed on the tail reducer.

[0010] Furthermore, by adjusting the length of the tension adjustment component, the distance between the upper pulley and the lower pulley is fixed, so that the synchronous belt is in a normal tensioned working state.

[0011] Furthermore, the tensioning adjustment assembly includes a bearing seat, a round nut, and a forward and reverse threaded rod. The bearing seat is arranged outside the rotating shaft of the upper pulley. One end of the forward and reverse threaded rod is installed on the outer ring of the bearing seat. The other end of the forward and reverse threaded rod is a pull ring. A circular rubber bushing is provided inside the pull ring, and the pull ring is passed through the outside of the shell of the lower pulley; the forward and reverse threaded rods are two threaded rods connected in the middle by a round nut, and the length of the forward and reverse threaded rods is adjusted by rotating the round nut.

[0012] Furthermore, it also includes a circular rubber bushing, a circular rubber bushing is provided in the pull ring, and the pull ring is sleeved on the outside of the shell of the lower pulley through the circular rubber bushing.

[0013] Furthermore, an overrunning clutch is provided inside the upper pulley, and the inner side surface of the upper pulley is connected to the rotating shaft of the upper pulley through the overrunning clutch.

[0014] Beneficial effects of the present invention:

[0015] 1. The transmission device of the present invention is driven by a synchronous belt and adopts a centrifugal clutch to control the disconnection and connection of the engine and the transmission device. By adjusting the length of the tension adjustment assembly, the spacing between the upper pulley and the lower pulley is fixed, so that the synchronous belt is in a normal tensioned working state. At the same time, the tension load of the synchronous belt is transmitted to the fuselage structure through the connection between the small pull rod mechanism on the upper part of the tension adjustment assembly and the fuselage structure, thereby isolating the vibration of the piston engine from being transmitted to the transmission system. At the same time, the influence of the vertical or horizontal displacement caused by the vibration of the piston engine on the tension of the synchronous belt is greatly reduced, thereby improving the rotation stability and service life of the synchronous belt.

[0016] 2. A circular rubber bushing is designed at the lower end of the tension adjustment assembly to reduce the vibration of the engine and reduce the load transmitted to the fuselage.

[0017] 3. The centrifugal clutch and the lower pulley are integrated into the clutch assembly. The engine power and speed are transmitted through the engine output shaft to the centrifugal clutch and then to the lower pulley, reducing the overall size.

[0018] 4. At the same time, the lower pulley is designed close to the engine end, which reduces the cantilever length of the lower pulley and improves the supporting rigidity of the lower pulley.

[0019] 5. Compared with V-belts of the same size, synchronous belts have the characteristics of greater power transmission and a wider range of reduction ratios.

[0020] 6. This transmission device not only solves the problem of starting a piston engine with load, reduces the vibration of the engine and isolates the engine vibration from being transmitted to the transmission device, thereby improving the fatigue life and overhaul interval of the moving parts, but also eliminates the complex synchronous belt bracket, tensioner mechanism and power shaft diaphragm coupling assembly, and adopts a first-level synchronous belt to transmit power separately to the main reducer and tail reducer. Its structure is simple, compact and practical, which not only reduces the weight of the transmission system and improves the power-to-weight ratio of the transmission system, but also is safe and reliable, with low use and maintenance costs. The present invention is suitable for light helicopters driven by synchronous belts. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a light helicopter transmission device driven by a synchronous belt according to the present invention;

[0022] Figure 2 A schematic diagram of a clutch assembly of the present invention;

[0023] Among them, 1 is the main reducer, 2 is the upper pulley, 3 is the tensioning adjustment assembly, 4 is the bearing seat, 5 is the tail drive shaft assembly, 6 is the annular rubber bushing, 7 is the tail reducer, 8 is the clutch assembly, 9 is the engine, 10 is the synchronous belt, 11 is the engine output shaft, 12 is the lower pulley, 13 is the support ball bearing, 14 is the centrifugal clutch, 15 is the forward and reverse threaded rod, 16 is the round nut. DETAILED DESCRIPTION

[0024] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships for the purposes of the accompanying drawings, and are intended only to facilitate the description of the present invention and simplify the description, rather than to indicate or imply that the device or case referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. In addition, the terms "first", "second" and the like are used for descriptive purposes only, and should not be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second" and the like may explicitly or implicitly include more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0026] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, detachable, or integrated connections; mechanical or point connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] A light helicopter transmission device driven by a synchronous belt includes a main reducer 1, an upper pulley 2, a tension adjustment assembly 3, a tail transmission shaft assembly 5, a tail reducer 7, a clutch assembly 8 and a synchronous belt 10; the power and speed of an engine 9 are connected to the clutch assembly 8, the outer side of the clutch assembly 8 is a lower pulley, and the lower pulley is connected to the synchronous belt 10. When the speed of the clutch assembly 8 reaches a certain value, the lower pulley rotates with the inside of the clutch assembly 8 under the action of the clutch; the other side of the synchronous belt 10 is connected to the upper pulley 2, one axial end of the upper pulley 2 is engaged with the main reducer 1 to transmit motion to the main rotor, and the other axial end of the upper pulley 2 is transmitted to the tail reducer 7 via the tail transmission shaft assembly 5; a tension adjustment assembly 3 is provided between the end of the lower pulley and the end of the upper pulley 2.

[0028] The engine 9 is flexibly installed below the main reducer 1 .

[0029] One end of the upper pulley 2 that engages with the main reducer 1 is a bevel gear, and the lower end of the main reducer 1 is a first-stage bevel gear. The bevel gear of the upper pulley 2 engages with the first-stage bevel gear of the main reducer 1, and the rotation direction is reversed.

[0030] The other end of the upper pulley 2 is the axially extending tail drive shaft assembly 5, which is a long shaft. The other end of the tail drive shaft assembly 5 is terminated by a bevel gear. The bevel gear of the tail drive shaft assembly 5 is reduced and reversed by the first-stage bevel gear of the tail reducer 7 and transmitted to the tail rotor installed on the tail reducer 7.

[0031] By adjusting the length of the tension adjustment component 3, the distance between the upper pulley 2 and the lower pulley 13 is fixed, so that the synchronous belt 10 is in a normal tension working state.

[0032] The tensioning adjustment assembly 3 includes a bearing seat 4, a round nut 16, and a forward and reverse threaded rod 15. The bearing seat 4 is arranged outside the rotating shaft of the upper pulley 2. One end of the forward and reverse threaded rod 15 is installed on the outer ring of the bearing seat 4. The other end of the forward and reverse threaded rod 15 is a pull ring. A circular rubber bushing 6 is provided inside the pull ring. The pull ring is sleeved on the outside of the housing of the lower pulley; the forward and reverse threaded rods 15 are two threaded rods connected in the middle by a round nut 16. The length of the forward and reverse threaded rods 15 is adjusted by rotating the round nut 16.

[0033] It also includes a circular rubber bushing 6. The circular rubber bushing 6 is arranged inside the pull ring, and the pull ring is sleeved on the outside of the housing of the lower pulley through the circular rubber bushing 6.

[0034] An overrunning clutch is provided inside the upper pulley 2, and the inner side surface of the upper pulley 2 is connected to the rotating shaft of the upper pulley 2 through the overrunning clutch.

[0035] The following is another embodiment of the present invention.

[0036] The technical solution adopted by the present invention is: a light helicopter transmission device driven by a synchronous belt, including a main reducer 1, an upper pulley 2, a tensioning adjustment component 3, a tail drive shaft component 5, a tail reducer 7, a clutch component 8 and a synchronous belt 10; the engine 9 is flexibly installed under the main reducer 1, and the power and speed of the engine 9 are transmitted to the synchronous belt 10 through the clutch component 8, and are transmitted to the main rotor and the tail rotor through the synchronous belt 10 and the upper pulley 2 in two ways, one of which is transmitted to the main rotor installed on the main reducer 1 through the first-stage bevel gear reduction reversing of the main reducer 1, and the other is transmitted to the tail reducer 7 through the tail drive shaft component 5, and is transmitted to the tail rotor installed on the tail reducer 7 through the first-stage bevel gear reduction reversing of the tail reducer 7; by adjusting the length of the tensioning adjustment component 3, the spacing between the upper pulley 2 and the lower pulley 13 is fixed, so that the synchronous belt 10 is in a normal tensioned working state, and the tensioning adjustment Assembly 3 consists of an upper bearing seat 4, a round nut 16, a threaded rod 15, and an annular rubber bushing 6. One end supports the main reducer 1 input shaft via the bearing seat 4, and the other end is supported on the clutch assembly 8 via the annular rubber bushing 6. The length of the tension adjustment assembly 3 is adjusted by fixing the threaded rod 15 and rotating the round nut 16. The upper pulley 2 is fixedly connected to the main reducer 1 input shaft via a bolt assembly. An overrunning clutch can be designed within the upper pulley 2 to disconnect the engine from the transmission in the event of engine failure, allowing the helicopter to autorotate and descend. The clutch assembly 8 is designed with a centrifugal clutch 14. When the engine is at low speed, the clutch 14 is disengaged, disconnecting the engine from the rotor load. When the engine is at high speed (normal operating speed), the clutch 14 is engaged, allowing the engine to drive the main rotor and tail rotor through the transmission. The clutch assembly 8 consists of a lower pulley 12, a supporting ball bearing 13, and a centrifugal clutch 14. The centrifugal clutch 14 is fixedly connected to the lower pulley 12 by bolts, and the lower pulley is mounted on the engine input shaft 11 through a bearing. The engine power and speed are transmitted to the centrifugal clutch 14 and the lower pulley 12 through the engine output shaft 11; the tensioning adjustment assembly 3 is mounted on the engine output shaft 11 through a bearing, serving as the lower support of the tensioning adjustment assembly 3.

[0037] This transmission is driven by a synchronous belt and uses a centrifugal clutch to control the disconnection and connection between the engine and the transmission. By adjusting the length of the tension adjustment assembly 3, the spacing between the upper pulley 2 and the lower pulley 12 is fixed, so that the synchronous belt 10 is in a normal tensioned working state. The lower end of the tension adjustment assembly 3 is designed with an annular rubber bushing 6 to reduce engine vibration. The centrifugal clutch and the lower pulley are integrated into the clutch assembly. The engine power and speed are transmitted to the lower pulley 12 via the centrifugal clutch 14 through the engine output shaft 11, thereby reducing the overall dimensions. Compared with V-belts of the same size, synchronous belts have the characteristics of high power transmission and a wide reduction ratio range. This transmission not only solves the problem of starting a piston engine under load, but also reduces engine vibration and isolates engine vibration from being transmitted to the transmission device, thereby improving the fatigue life of the moving parts and the overhaul interval. At the same time, its structure is simple and practical, which not only reduces the weight of the transmission system and improves the power-to-weight ratio of the transmission system, but also is safe and reliable, with low use and maintenance costs. The present invention is suitable for light helicopters driven by synchronous belts.

[0038] The above description is merely a detailed description of specific embodiments of the present invention. Any unspecified portions are conventional techniques. However, the scope of the present invention is not limited thereto. Any changes or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed in the present invention are intended to be encompassed within the scope of the present invention. The scope of the present invention shall be determined by the scope of the claims.

Claims

1. A light helicopter transmission device driven by a synchronous belt, characterized in that: The invention comprises a main reducer (1), an upper pulley (2), a tension adjustment component (3), a tail transmission shaft component (5), a tail reducer (7), a clutch component (8) and a synchronous belt (10); the power and speed of the engine (9) are connected to the clutch component (8); the outer side of the clutch component (8) is a lower pulley, and the lower pulley is connected to the synchronous belt (10); when the speed of the clutch component (8) reaches a certain value, the lower pulley rotates inside the clutch component (8) under the action of the clutch; the other side of the synchronous belt (10) is connected to the upper pulley (2); one axial end of the upper pulley (2) is engaged with the main reducer (1) to transmit the motion to the main rotor, and the other axial end of the upper pulley (2) is transmitted to the tail reducer (7) through the tail transmission shaft component (5); a tension adjustment component (3) is provided between the end of the lower pulley and the end of the upper pulley (2); by adjusting the tension adjustment component (3 ) length, so that the spacing between the upper pulley (2) and the lower pulley (13) is a fixed value, so that the synchronous belt (10) is in a normal tensioning working state; the tensioning adjustment component (3) includes a bearing seat (4), a round nut (16), and a positive and negative threaded rod (15), the bearing seat (4) is arranged outside the rotating shaft of the upper pulley (2), one end of the positive and negative threaded rod (15) is installed on the outer ring of the bearing seat (4), and the other end of the positive and negative threaded rod (15) is a pull ring, a circular rubber bushing (6) is arranged in the pull ring, and the pull ring is sleeved outside the shell of the lower pulley; the positive and negative threaded rod (15) is two threaded rods connected in the middle by a round nut (16), and the length of the positive and negative threaded rod (15) is adjusted by rotating the round nut (16); it also includes a circular rubber bushing (6), a circular rubber bushing (6) is arranged in the pull ring, and the pull ring is sleeved outside the shell of the lower pulley through the circular rubber bushing (6).

2. A synchronous belt driven light helicopter transmission according to claim 1, characterized in that: The engine (9) is flexibly installed below the main reducer (1).

3. The synchronous belt driven light helicopter transmission according to claim 1, characterized in that: One end of the upper pulley (2) meshing with the main reducer (1) is a bevel gear, and the lower end of the main reducer (1) is a first-stage bevel gear. The bevel gear of the upper pulley (2) meshes with the first-stage bevel gear of the main reducer (1) and reverses the rotation direction.

4. A synchronous belt driven light helicopter transmission according to claim 3, characterized in that: The other end of the upper pulley (2) is an axially extended tail transmission shaft assembly (5), the tail transmission shaft assembly (5) is a long shaft, and the other end of the tail transmission shaft assembly (5) is a bevel gear. The bevel gear of the tail transmission shaft assembly (5) is decelerated and reversed by the first-stage bevel gear of the tail reducer (7) and transmitted to the tail rotor installed on the tail reducer (7).

5. The synchronous belt driven light helicopter transmission according to claim 1, characterized in that: An overrunning clutch is provided inside the upper pulley (2), and the inner side surface of the upper pulley (2) is connected to the rotating shaft of the upper pulley (2) via the overrunning clutch.

Images