Impact load limiting device for airship power transmission system

Abstract

The invention discloses an impact load limiting device for an airship power transmission system, which comprises a round nut, a disc spring pressing plate, a friction plate pressing plate and a friction disc which are sequentially arranged on an input half shaft, friction plates are arranged between the friction disc and the friction plate pressing plate as well as between the friction disc and an outer flange of the input half shaft, and the round nut is connected to the input half shaft. The compression bolt is in threaded connection with the round nut, a disc spring is arranged on the disc spring pressing plate, and the compression bolt can compress the disc spring pressing plate so as to compress the disc spring; and the disc spring deforms to press the friction plate pressing plate, so that constant pressure is generated on the contact surface of the friction plate and the friction disc. The device can stably limit the impact load at the starting moment of the engine.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft power transmission systems, and in particular relates to an impact load limiting device for an airship power transmission system. Background Art

[0002] The power transmission system on aircraft such as helicopters and airships is a mechanical system used to transfer the power of the engine to the propeller or rotor. According to CCAR-27-R1 "Airworthiness Regulations for Normal Category Rotorcraft", CCAR-29-R1 "Airworthiness Regulations for Transport Category Rotorcraft", and the European version of "Airworthiness Standards for Transport Category Airships", the power transmission system mainly includes reducers, transmission shafts, universal joints, couplings, rotor brakes, clutches, shaft support devices, and any additional mounts, accessory transmission devices, and cooling fans connected to or installed on the rotor transmission system. For power transmission systems that use aviation piston engines as power sources, during the starting phase of the piston engine, the impact load and vibration levels are both large. Generally, buffering or isolation methods are used to solve the problems of excessive starting impact loads and vibrations. There are mainly three methods:

[0003] One is to set up a kinetic energy absorbing shaft. The kinetic energy absorbing shaft is a metal shaft with low rigidity and strong impact resistance set in the shaft system. The shaft has a strong torsional deformation energy absorption capacity. When a certain degree of overload occurs, the kinetic energy absorbing shaft can play a certain role in buffering and absorbing energy through torsional elastic deformation. However, the buffering and energy absorption effect of the kinetic energy absorbing shaft is limited, and it cannot adapt to high-frequency periodic impact loads. In addition, as a rigid connection device, the kinetic energy absorbing shaft cannot adapt to the large vibration of the engine.

[0004] The second is to set up an elastic coupling. There are many forms of elastic couplings, including non-metallic elastic couplings and metal elastic couplings. The buffering and energy absorption principle is similar to that of kinetic energy absorption shafts. When a certain degree of overload occurs, the deformation of the elastic body is used to play a certain buffering and energy absorption role. The buffering and energy absorption effect of the elastic coupling is also relatively limited. It cannot absorb large impact loads, nor can it adapt to large engine vibrations.

[0005] The third is to set up a clutch. The working mechanism of the clutch is completely different. When the engine starts, the clutch connection is disconnected and the engine starts without load. After the engine runs smoothly, the clutch is engaged and the engine power is connected to the transmission system. At this time, the engine is already in a stable running state and there is no large impact load. However, this method requires the engine to have the ability to start without load.

[0006] Aviation piston engines have the characteristic of large starting impact loads. If kinetic energy absorbing shafts and elastic couplings are used, the buffering and energy absorption effect is limited, and it is difficult to achieve a good stiffness match. When the stiffness is low, the energy absorption effect is good, but torsional vibration is easy to occur, which can easily lead to insufficient system strength; when the stiffness is high, the energy absorption effect is poor and the buffering capacity is insufficient. If a clutch is used to isolate the impact, the engine must first have the ability to start at no load. Even if the engine has the ability to start at no load, a clutch control device must be added to control the opening and closing of the clutch. The general clutch is large in size and heavy in weight, which is not conducive to aircraft weight control.

[0007] The layout of the airship power transmission system is shown in Figure 1 , including engine mounting seat a, aviation piston engine b, engine output shaft c, impact load limiting device d, transmission system e, propeller f, transmission system mounting seat g. Since some aviation piston engines are designed to start with load (flying overspeed will occur when starting without load), a large impact load will be generated at the moment of starting (see the typical impact load curve for the curve). Figure 2 ), which may cause impact damage to the transmission system and propeller. In addition, aviation piston engines are generally installed at the tail, and at the moment of starting, the engine b will produce a large vibration displacement (see the schematic diagram of engine vibration displacement Figure 3 ), resulting in a large coaxiality error between the engine output shaft c and the power transmission system e, causing additional vibration loads. Summary of the invention

[0008] Purpose of the Invention

[0009] In order to solve the problem of excessive impact load at the moment of starting an aviation piston engine, the present invention provides an impact load limiting device for an airship power transmission system.

[0010] Inventing technical solutions

[0011] An impact load limiting device for an airship power transmission system comprises a round nut, a disc spring pressure plate, a friction plate pressure plate and a friction disc which are sequentially arranged on an input half shaft, friction plates are arranged between the friction disc and the friction plate pressure plate and between the friction disc and an outer flange of the input half shaft, the round nut is connected to the input half shaft, a clamping bolt is threadedly connected to the round nut, a disc spring is arranged on the disc spring pressure plate, the clamping bolt can clamp the disc spring pressure plate, thereby clamping the disc spring; the disc spring deforms and clamps the friction plate pressure plate, so that a constant pressure is generated on the contact surface between the friction plate and the friction disc.

[0012] Preferably, the end of the input half shaft is located in a groove at one end of the transition disc, and the friction disc is connected to the transition disc.

[0013] Preferably, the output half shaft is arranged at the other end of the transition disc.

[0014] Preferably, a self-lubricating bearing bushing is arranged between the friction disc and the input half shaft.

[0015] Preferably, a plurality of limiting edges are provided in the inner hole of the disc spring pressure plate, and the limiting edges are in contact with the edges at corresponding positions on the input semi-shaft in a planar manner.

[0016] Preferably, a plurality of limiting blind holes are provided on the end surface of the disc spring pressure plate, and the ends of the clamping bolts can extend into the limiting blind holes.

[0017] Preferably, the input shaft 1 is connected to the input half shaft via a drum spline.

[0018] Preferably, the output half shaft is connected to the output shaft via a drum spline.

[0019] Preferably, the contact surface between the friction plate pressure plate and the disc spring is an inclined surface.

[0020] Preferably, an elastic body is arranged between the output half shaft and the transition disc.

[0021] The advantages of the present invention are as follows: the device can stably limit the impact load at the moment of engine starting. By utilizing the basic principle of friction slip, it is possible to ensure that a stable pressure is applied to the friction plate and a stable impact load limit is maintained, that is, neither excessive impact load is transmitted nor the load transmission capacity is reduced; compared with buffering and vibration reduction devices such as elastic shafts and elastic couplings, the impact load limiting capacity of the present device is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the layout diagram of the airship power transmission system.

[0023] Figure 2 This is a typical impact load curve.

[0024] Figure 3 It is a schematic diagram of engine vibration displacement.

[0025] Figure 4 The present invention is a structural outline diagram of an impact load limiting device for an airship power transmission system.

[0026] Figure 5 It is a detailed structural diagram of an impact load limiting device for an airship power transmission system according to the present invention.

[0027] Figure 6 The present invention is a schematic diagram of a disc spring pressure plate limiting structure used in an impact load limiting device of an airship power transmission system.

[0028] Figure 7 The invention is a schematic diagram of the installation between a disc spring pressure plate and an input half shaft in an impact load limiting device for an airship power transmission system.

[0029] Figure 8 The present invention is a schematic diagram of a round nut anti-loosening device used in an impact load limiting device of an airship power transmission system.

[0030] Fig. 9 The present invention is a schematic structural diagram of a friction plate pressure plate used in an impact load limiting device of an airship power transmission system.

[0031] Fig.10 It is a schematic diagram of the position of an elastic body in an impact load limiting device for an airship power transmission system of the present invention.

[0032] In the figure, 1, input shaft; 2, input half shaft; 3, clamping bolt; 4, round nut; 5, disc spring pressure plate; 6, disc spring; 7, friction plate pressure plate; 8, friction plate; 9, self-lubricating bearing bushing; 10, friction disc; 11, transition disc; 12, elastomer; 13, output half shaft; 14, cover; 15, output shaft; 16, drum spline. DETAILED DESCRIPTION

[0033] The present invention is achieved through the following technical solutions.

[0034] An impact load limiting device for an airship power transmission system comprises a disc spring pressure plate 5, a disc spring 6, a friction plate pressure plate 7, a friction plate 8, a friction disc 10, and an elastic body 12. An input shaft 1 is connected to an input half shaft 2, an output half shaft 13 is arranged in and connected to a housing 14, and an output shaft 15 is connected to an inner hole of the output half shaft 13. The input half shaft 2 and the output half shaft 13 are respectively located at two ends of a transition disc 11.

[0035] The input shaft 1 and input half shaft 2, the output half shaft 13 and the output shaft 15 are all connected by a drum spline 16. The ball joint connection effect of the drum spline 16 can adapt to the larger coaxiality error between the input shaft 1 and the output shaft 15, greatly increasing the device's adaptability to different axialities and helping to adapt to the large amplitude vibration at the moment of engine starting.

[0036] The round nut 4 is installed on the input half shaft 2 through a thread, and the clamping bolt 3 compresses the disc spring pressure plate 5 through the bolt hole on the round nut 4, thereby compressing the disc spring 6; the disc spring 6 deforms to produce a constant pressure to compress the friction plate pressure plate 7, thereby ensuring a constant pressure on the contact surface between the friction plate 8 and the friction disc 10; and the friction disc 10 and the input half shaft 2 are connected by a self-lubricating bushing bearing 9. In this way, when the impact load exceeds the set value, relative sliding occurs between the friction plate 8 and the friction disc 10, and the impact load is stably controlled; when the impact load is lower than the set value, there is no relative movement between the friction plate 8 and the friction disc 10, and the load is stably transmitted. The friction disc 10 is connected to the transition disc 11. Several round nuts 4 can be set as needed.

[0037] Four limiting edges 18 are set on the inner hole of the disc spring pressure plate 5, and six limiting blind holes 17 are set on the end surface. The limiting edges 18 fit the edges on the input half shaft 2, thereby limiting the rotation of the disc spring pressure plate 5. The clamping bolt 3 enters the limiting blind hole 17, thereby limiting the rotation of the clamping bolt 3 and the round nut 4 as a whole. This prevents the round nut 4 from loosening and causing the clamping force to change, and prevents the load limit value from changing.

[0038] The friction plate pressure plate 7 adopts a slope compensation design to compensate for the axial clearance caused by a certain degree of wear of the friction plate 8, thereby ensuring that the clamping force of the disc spring 6 on the friction plate 8 is within the allowable range and ensuring that the impact load limit value does not change due to the wear of the friction plate.

[0039] An elastic body 12 is arranged between the transition disc 11 and the output half shaft 13 to play a certain role in buffering and vibration reduction and coaxial compensation.

[0040] The protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these changes and modifications.

Claims

1. An impact load limiting device for an airship power transmission system, characterized in that: The invention comprises a round nut (4), a disc spring pressure plate (5), a friction plate pressure plate (7), and a friction disc (10) which are arranged in sequence on an input half shaft (2); a friction plate (8) is arranged between the friction plate (10) and the friction plate pressure plate (7) and between the friction plate (10) and the outer flange of the input half shaft (2); the round nut (4) is connected to the input half shaft (2); a clamping bolt (3) is threadedly connected to the round nut (4); a disc spring (6) is arranged on the disc spring pressure plate (5); the clamping bolt (3) can clamp the disc spring pressure plate (5), thereby clamping the disc spring (6); the disc spring (6) deforms to clamp the friction plate pressure plate (7), so that a constant pressure is generated on the contact surface between the friction plate (8) and the friction disc (10).

2. The impact load limiting device for an airship power transmission system according to claim 1, characterized in that: The end of the input half shaft (2) is located in a groove at one end of the transition disc (11), and the friction disc (10) is connected to the transition disc (11).

3. The impact load limiting device for an airship power transmission system according to claim 2, characterized in that: The output half shaft (13) is arranged at the other end of the transition disc (11).

4. The impact load limiting device for an airship power transmission system according to claim 3, characterized in that: A self-lubricating bearing bushing (9) is arranged between the friction disc (10) and the input half shaft (2).

5. The impact load limiting device for an airship power transmission system according to claim 1, characterized in that: A plurality of limiting edges (18) are arranged in the inner hole of the disc spring pressure plate (5), and the limiting edges (18) are in contact with the edges at corresponding positions on the input semi-shaft (2) in a planar manner.

6. The impact load limiting device for an airship power transmission system according to claim 1, characterized in that: A plurality of round nuts (4) and clamping bolts (3) are provided, and a plurality of limiting blind holes (17) are provided at positions corresponding to the end faces of the disc spring pressure plate (5) and the round nuts (4), and the ends of the clamping bolts (3) can extend into the limiting blind holes (17).

7. The impact load limiting device for an airship power transmission system according to claim 1, characterized in that: The input shaft (1) is connected to the input half shaft (2) via a drum spline (16).

8. The impact load limiting device for an airship power transmission system according to claim 3, characterized in that: The output half shaft (13) is connected to the output shaft (15) via a drum spline (16).

9. The impact load limiting device for an airship power transmission system according to claim 1, characterized in that: The contact surface between the friction plate pressure plate (7) and the disc spring (6) is an inclined surface.

10. The impact load limiting device for an airship power transmission system according to claim 3, characterized in that: An elastic body (12) is arranged between the output half shaft (13) and the transition disc (11).

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