An accessory gearbox

Abstract

The application relates to an accessory gearbox. The accessory gearbox comprises an accessory casing, a plurality of pull rods, one end of which is connected with the accessory casing and the other end of which is connected with an engine body of an aero-engine, a plurality of strain gauges arranged on the surface of the accessory casing and used for monitoring the strain state of the accessory gearbox in real time, and at least one air spring damper, one end of which is connected with a spherical hinge of the accessory casing and the other end of which is connected with the engine body, wherein the air spring damper adjusts the length and the rigidity thereof based on the strain state of the accessory gearbox to realize deformation coordination of the accessory gearbox. The application provides the accessory gearbox which can realize deformation coordination, weaken the transmission of vibration impact load and further improve the safety and reliability of the accessory gearbox.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine structural design, and particularly relates to an accessory gearbox. BACKGROUND

[0002] The accessory gearbox is a unit of the aero-engine transmission system, and its main function is to drive the high-pressure rotor to rotate through the transmission system by the starter when the engine starts, and to drive the engine accessories to work by extracting power from the high-pressure rotor when the engine works normally. The accessory gearbox needs to provide installation interfaces for fuel pumps, oil pumps, control generators and the like and drive them to work normally. The accessory gearbox is generally connected with the engine body through hangers, pull rods, positioning pins and the like.

[0003] The accessory gearbox contains multiple gears and gear shafts, and has the characteristics of high power density and thin wall in consideration of the space of the aero-engine accessories and the lightweight requirement of the whole machine. However, such characteristics cause the deformation of the gearbox during the operation of the engine, which leads to problems such as misalignment of the gear shaft and stress concentration of the casing, and further affects the reliability and safety of the accessory gearbox.

[0004] In addition, the accessory gearbox has a complex configuration, contains multiple meshing gears and gear shafts, and has many state points during the operation of the engine, which leads to the fact that some natural frequencies of the accessory gearbox are included in the working speed range of the aero-engine. During the operation of the engine, these natural frequencies are easily excited to resonate by the gear meshing frequency and the gear shaft rotation frequency, and the vibration is transmitted to the aero-engine body through the connecting piece, which may cause fatigue failure of the engine parts such as pipelines. On the other hand, various vibration impact loads of the engine body are also transmitted to the accessory gearbox through the connecting piece, which aggravates the vibration of the accessory gearbox and affects the fatigue life. SUMMARY

[0005] In view of the above problems of the prior art, the present application provides an accessory gearbox which can realize deformation coordination, weaken the transmission of vibration impact loads, and further improve the safety and reliability of the accessory gearbox.

[0006] Specifically, the present application provides an accessory gearbox suitable for an aero-engine, which comprises:

[0007] an accessory casing;

[0008] a plurality of pull rods, one end of each of which is connected with the accessory casing, and the other end of each of which is connected with an engine body of the aero-engine;

[0009] a plurality of strain gauges arranged on the surface of the accessory casing and used for monitoring the strain state of the accessory gearbox in real time;

[0010] At least one air spring damper, one end of which is connected to the accessory case via a spherical hinge, and the other end of which is connected to the engine body, adjusts its length and stiffness to achieve deformation coordination of the accessory gear box based on the strain state of the accessory gear box.

[0011] According to one embodiment of the present application, the accessory gear box further comprises a controller and an air pump, the controller is used to receive strain signals obtained by a plurality of strain gauges, and calculate the strain state of the accessory gear box and generate control instructions based on the strain signals;

[0012] The air pump is connected to the air spring damper, and the air pump controls the amount and pressure of air entering the air spring damper according to the control instructions to adjust the length and stiffness of the air spring damper.

[0013] According to one embodiment of the present application, the controller is integrated in the control system of the engine.

[0014] According to one embodiment of the present application, the air pump is installed on the accessory case or the engine body.

[0015] According to one embodiment of the present application, the air spring damper is connected to the engine body in a spherical hinge, hinge or fixed connection.

[0016] According to one embodiment of the present application, the air spring damper comprises a tubular air bag and a piston, the air pump inflates the tubular air bag, and the piston moves outward along the central axis of the tubular air bag to increase the length of the air spring damper; the air pump deflates the tubular air bag, and the piston compresses inward along the central axis of the tubular air bag to shorten the length of the air spring damper.

[0017] According to one embodiment of the present application, the air spring damper further comprises a damper arranged on the central axis of the tubular air bag.

[0018] According to one embodiment of the present application, the air spring damper is filled with liquid, and the piston valve of the piston has a sealing structure.

[0019] According to one embodiment of the present application, the accessory gear box comprises a first accessory mounting seat and a second accessory mounting seat, which are arranged on both sides of the accessory case respectively.

[0020] According to one embodiment of the present application, the strain gauges are close to the pull rod and the air spring damper.

[0021] The accessory gearbox provided by the application is connected with the engine body through an air spring damper, deformation coordination is realized through the air spring damper, and transmission of vibration impact load is weakened, thereby improving the safety and reliability of the accessory gearbox.

[0022] It should be understood that the above general description and the following detailed description of the application are exemplary and illustrative, and are intended to provide further explanation of the application described. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application, illustrate embodiments of the application, and together with the description serve to explain the principles of the application.

[0024] In the drawings:

[0025] Figure 1 A structural schematic diagram of an accessory gearbox in an embodiment of the application is shown.

[0026] Figure 2 A perspective view of an accessory gearbox in an embodiment of the application is shown.

[0027] Figure 3 A structural schematic diagram of an air spring damper in an embodiment of the application is shown.

[0028] Among them, the above drawings include the following reference signs:

[0029] Accessory gearbox 100

[0030] Accessory gearbox 101

[0031] Pull rod 102

[0032] Strain gauge 103

[0033] Air spring damper 104

[0034] Controller 105

[0035] Air pump 106

[0036] Tubular air bag 107

[0037] Piston 108

[0038] Damper 109

[0039] Liquid 110

[0040] First accessory mounting seat 111

[0041] Second accessory mounting seat 112 DETAILED DESCRIPTION

[0042] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other in the case of no conflict.

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely in the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form, unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a feature, step, operation, device, component and / or combination thereof.

[0045] Unless otherwise specifically stated, the relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the various examples herein are not limiting but instead are exemplary. Also, it is to be understood that the specific devices illustrated in the attached drawings, and described in the best mode sections, are by way of example only and not by way of limitation. Techniques, methods, and apparatuses known and used by those of ordinary skill in the relevant art can not be discussed in detail, but are intended to be part of the scope of the present application. In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation on the scope of the exemplary embodiments. Thus, other examples of the exemplary embodiments can have different values. It is noted that like references and descriptions set forth herein (disregarding any reference to a figure) typically identify corresponding, akin, or similar items shown throughout the figures and described in the detailed description, and thus, once an item is defined in one figure, it need not be further discussed in further figures.

[0046] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are usually based on the orientation or position relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, without the opposite indication, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore, it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0047] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, rotated 90 degrees, or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0048] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0049] Figure 1 A schematic diagram of the accessory gearbox according to an embodiment of the present invention is shown. Figure 2 A perspective view of an accessory gearbox according to an embodiment of the present invention is shown. As shown, an accessory gearbox 100 suitable for an aircraft engine mainly includes an accessory housing 101, multiple tie rods 102, multiple strain gauges 103, and at least one air spring damper 104.

[0050] Each tie rod 102 has one end connected to the accessory housing 101 and the other end connected to the engine body of the aircraft engine.

[0051] Multiple strain gauges 103 are arranged on the surface of the accessory housing 101 for real-time monitoring of the strain state of the accessory gearbox 100.

[0052] The air spring damper 104 is connected to the accessory case 101 by a ball joint at one end and to the engine body at the other end. Based on the strain state of the accessory gearbox 100, the air spring damper 104 adjusts its length and stiffness to achieve deformation coordination of the accessory gearbox 100. The air pump 106 adjusts the amount and pressure of air in the air spring damper 104 by means of air charging and discharging. It should be noted that the operation of the aero-engine is a dynamic process, and therefore the deformation of the accessory gearbox 100 is also constantly changing. The present application dynamically adjusts the length and stiffness of the air spring damper 104, so that the strain at the key position of the accessory gearbox 100 is within a reasonable range, avoiding stress concentration of the accessory gearbox 100 and misalignment of the gear shaft of the accessory gearbox 100, thereby improving the reliability and safety of the accessory gearbox 100. In addition, one or more of the plurality of pull rods 102 can be replaced by air spring dampers 104 to further improve the reliability and safety of the accessory gearbox 100.

[0053] Preferably, the accessory gearbox 100 further comprises a controller 105 and an air pump 106. The controller 105 is used to receive the strain signals obtained by the plurality of strain gauges 103 (the strain signals are sent to the controller 105 in the direction indicated by the arrow), and calculate the strain state of the accessory gearbox 100 based on the strain signals. The controller 105 has a logical relationship between the strain state and the length and stiffness of the air spring damper 104. The controller 105 generates control instructions according to the strain state. The air pump 106 is connected to the air spring damper 104. The air pump 106 controls the amount and pressure of air entering the air spring damper 104 according to the control instructions sent by the controller 105 to adjust the length and stiffness of the air spring damper 104 in real time, and the control instructions are sent from the controller 105 to the air pump 106 in the direction indicated by the arrow.

[0054] Preferably, the controller 105 is integrated into the control system of the engine. As an example but not limitation, the controller 105 can also be a separate control device.

[0055] Preferably, the air pump 106 is installed on the accessory case 101 or the engine body.

[0056] Preferably, the air spring damper 104 is connected to the engine body by a ball joint, a hinge joint or a fixed connection.

[0057] Preferably, one end of the pull rod 102 is connected to the accessory case 101 by a ball joint, and the other end is connected to the engine body of the aero-engine by a ball joint, a hinge joint or a fixed connection.

[0058] Figure 3The structure of the air spring damper is shown in the figure. As shown in the figure, the air spring damper 104 comprises a tubular air bag 107 and a piston 108 arranged along the axis of the tubular air bag 107. When the air pump 106 inflates the tubular air bag 107, the piston 108 moves outward (upward in the figure) along the central axis of the tubular air bag 107 to increase the length of the air spring damper 104, and correspondingly changes the stiffness of the air spring damper 104. When the air pump 106 deflates the tubular air bag 107, the piston 108 is compressed inward (downward in the figure) along the central axis of the tubular air bag 107 to shorten the length of the air spring damper 104. The air pump 106 adjusts the amount and pressure of air in the air spring damper 104 by inflation and deflation, so as to change the length and stiffness of the air spring damper 104, and thereby affect the overall deformation of the accessory gearbox 100, so as to achieve deformation coordination of the accessory gearbox 100.

[0059] Preferably, the air spring damper 104 further comprises a damper 109 arranged on the central axis of the tubular air bag 107. The damper 109 not only has a damping effect (for reducing the amplitude of vibration transmitted between the engine body and the accessory gearbox 101), but also can withstand lateral forces to prevent excessive lateral deformation of the air spring damper 104. More preferably, the air spring damper 104 is filled with liquid 110. The piston valve of the piston 108 has a sealing structure. The air spring damper 104 achieves the vibration isolation effect between the engine body and the accessory gearbox 101 by cooperation of the liquid 110 and the piston valve of the piston 108, and the principle of vibration isolation is to convert the energy received by the liquid 110 into heat energy through the flow friction of the liquid 110, thereby achieving vibration isolation. Therefore, the air spring damper 104 has a damping effect, which can effectively weaken the transmission of vibration impact load between the accessory gearbox 100 and the engine body.

[0060] Preferably, referring to Figure 1 and Figure 2 , the accessory gearbox 100 further comprises a first accessory mounting seat 111 and a second accessory mounting seat 112. The first accessory mounting seat 111 and the second accessory mounting seat 112 are arranged on the two sides of the accessory gearbox 101, respectively. The deformation coordination of the accessory gearbox 100 achieved by the air spring damper 104 includes coordinating the deformation of the mounting hole of the first accessory mounting seat 111 and the second accessory mounting seat 112, minimizing the misalignment of the gear shaft, improving the gear meshing state, and reducing the degree of vibration.

[0061] Preferably, the strain gauges 103 are located close to the pull rod 102 and the air spring damper 104. Specifically, the strain gauges 103 are mounted on the accessory case 101 at the vicinity of the connection of the pull rod 102 and the air spring damper 104, and at the main force transmission path of the accessory gearbox 100. In this way, the strain response of the accessory gearbox 100 (mainly the accessory case 101) is obtained. The strain gauges 103 transmit the strain signals to the controller 105. It is readily understood that the mounting positions and the specific number of the strain gauges 103 can be determined according to the specific configuration and characteristics of the accessory gearbox 100.

[0062] The present application provides an accessory gearbox with the following advantages:

[0063] 1. The strain gauges are used to monitor the state of the accessory gearbox during engine operation, so as to control and adjust the air spring damper, thereby achieving the function of real-time active control.

[0064] 2. When the aircraft engine is running at a high state, the accessory power is high, and the heat transmitted from the engine body to the accessory gearbox is large, resulting in large deformation of the accessory gearbox. The present application adjusts the deformation of the accessory gearbox through the length and stiffness adjustment function of the air spring damper, effectively reduces the deformation of the accessory gearbox under the action of temperature and force, and avoids the misalignment of the gear shaft caused by the deformation of the accessory mounting seat and the accessory case.

[0065] 3. When the aircraft engine suffers a destructive event such as fan blade out (FBO), the engine body will be subjected to a strong impact load. The impact load is transmitted to the accessory gearbox through the air spring damper. The damper in the air spring damper of the present application plays a strong buffering role on the impact load, so that the impact load transmitted to the accessory gearbox is weakened, achieving good load reduction effect.

[0066] 4. When the accessory gearbox has problems such as vibration overrun and accessory shaft shear, the vibration load is transmitted to the engine body through the air spring damper. The damper in the air spring damper of the present application, in cooperation with the liquid and piston valve, achieves the damping function to weaken the vibration load, significantly reducing the influence of the abnormal accessory gearbox on the engine body.

[0067] It is obvious to those skilled in the art that various modifications and variations can be made to the above exemplary embodiments of the present application without departing from the spirit and scope of the present application. Therefore, it is intended to cover modifications and variations of the present application falling within the scope of the appended claims and their equivalents.

Claims

1. An accessory gearbox suitable for an aero-engine, the accessory gearbox comprising: an accessory case; a plurality of tie rods, one end of which is connected to the accessory case and the other end of which is connected to an engine body of the aero-engine; a plurality of strain gauges arranged on a surface of the accessory case for monitoring a strain state of the accessory gearbox in real time; at least one air spring damper, one end of which is connected to the accessory case via a spherical hinge and the other end of which is connected to the engine body, the air spring damper adjusting its length and stiffness to achieve deformation coordination of the accessory gearbox based on the strain state of the accessory gearbox.

2. An accessory gearbox as claimed in claim 1, characterised in that, a controller and an air pump are further included, the controller being configured to receive strain signals obtained by the plurality of strain gauges, calculate the strain state of the accessory gearbox based on the strain signals and generate control instructions; the air pump is connected to the air spring damper, the air pump controlling the amount and pressure of air entering the air spring damper according to the control instructions to adjust the length and stiffness of the air spring damper.

3. An accessory gearbox as claimed in claim 2, characterised in that, the controller is integrated into a control system of the engine.

4. The accessory gearbox of claim 2, wherein, the air pump is mounted on the accessory case or the engine body.

5. The accessory gearbox of claim 1, wherein, the air spring damper is connected to the engine body via a spherical hinge, a hinge or a fixed connection.

6. The accessory gearbox of claim 2, wherein, the air spring damper comprises a tubular air bag and a piston, the air pump inflates the tubular air bag, and the piston moves outward along the central axis of the tubular air bag to increase the length of the air spring damper; the air pump deflates the tubular air bag, and the piston compresses inward along the central axis of the tubular air bag to shorten the length of the air spring damper.

7. An accessory gearbox as claimed in claim 6, characterised in that, the air spring damper further comprises a damper arranged on the central axis of the tubular air bag.

8. An accessory gearbox as claimed in claim 7, characterised in that, the air spring damper is filled with liquid, and a piston valve of the piston has a sealing structure.

9. The accessory gearbox of claim 1, wherein, the accessory gearbox comprises a first accessory mounting seat and a second accessory mounting seat arranged on two sides of the accessory case respectively.

10. The accessory gearbox of claim 1, wherein, the strain gauges are arranged close to the tie rods and the air spring damper.

Images