Tension spring connecting mechanism and aircraft landing gear

Abstract

The invention discloses a tension spring connecting mechanism and an aircraft landing gear, and relates to the field of aircraft landing gears, the tension spring connecting mechanism comprises a tension spring main body and a connecting assembly arranged at the end part of the tension spring main body; the connecting assembly comprises a neck bush arranged on the inner ring of the tension spring body in a sleeving mode, an outer bush arranged on the outer ring of the tension spring body in a sleeving mode and a pull rod arranged in the neck bush. The neck bush is integrally arranged on the inner ring of the tension spring body in a sleeved mode, and the outer thread groove formed in the outer circumferential face of the neck bush is meshed with the spiral spring wire of the tension spring body, so that the axial tension of the end of the tension spring body is transmitted through a multi-circle thread meshing face, and a hook structure which is prone to generating stress concentration in a traditional tension spring is fundamentally replaced. The outer ring of the tension spring body is sleeved with the outer lining, the outer lining and the inner lining jointly form radial clamping on the tension spring body, the rigidity and stability of the connecting portion are enhanced, and the tension spring body is limited from being disengaged from the outer thread groove of the inner lining due to stress deformation in the radial direction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft landing gear, in particular to a tension spring connecting mechanism and aircraft landing gear. BACKGROUND

[0002] In the aircraft landing gear, the upper lock adopts a hook lock structure, and when the landing gear is retracted, the hook is locked to prevent accidental release. The lock connecting rod is a transmission component of the upper lock, and is connected with the unlocking actuator cylinder and the hook to realize the switching of the locking state. The two ends of the tension spring are connected with the lock connecting rod, and the tension is applied to maintain the position of the lock connecting rod, thereby enhancing the stability of the upper lock in the vibration environment and ensuring that the lock connecting rod passes through the dead point and reliably stays in the locked position.

[0003] In the traditional structure, the two ends of the tension spring are directly bent into semi-closed hooks, and the two hooks are hung on the upper and lower lock connecting rods, respectively. The installation is very intuitive and fast. However, at the root of the hook (the inner side of the smallest bending radius), severe stress concentration occurs, and under the action of large-amplitude alternating tensile load caused by frequent take-off and landing of the aircraft, fatigue micro-cracks are easily generated and expanded from this place. In severe cases, the tension spring may break, which may cause the upper lock to accidentally disengage, and the landing gear may not be placed in position or locked after being retracted, directly affecting flight safety. SUMMARY

[0004] In order to overcome the above technical problems, the purpose of the present application is to provide a tension spring connecting mechanism and aircraft landing gear.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A tension spring connecting mechanism, comprising: a tension spring body and a connecting assembly arranged at the end of the tension spring body; The connecting assembly comprises an inner bushing arranged in the inner circle of the tension spring body, an outer bushing arranged in the outer circle of the tension spring body, and a pull rod arranged in the inner bushing; Wherein, the outer circumferential surface of the inner bushing is provided with an outer thread groove, the helical spring wire of the tension spring body is arranged in the outer thread groove, the inner bushing and the outer bushing jointly form a radial clamping to the tension spring body, the side of the pull rod towards the inside of the tension spring body has a radially extended limiting block, the limiting block and the outer bushing jointly form an axial limiting to the inner bushing, the other side of the pull rod has a connecting part extending out of the outer bushing, and the connecting part is used to connect with external structures.

[0007] As a further scheme of the present application, the outer thread groove is matched with the pitch and cross-sectional shape of the helical spring wire of the tension spring body.

[0008] As a further scheme of the present application, the connecting part of the pull rod is provided with a through hole for connecting with an external structure.

[0009] As a further scheme of the present application, the connecting assembly is provided with two groups, and the two groups of the connecting assembly are connected to the two ends of the pull spring body respectively.

[0010] As a further scheme of the present application, the end of the outer bushing is provided with an inward and radially extending flange, the two ends of the inner bushing are provided with a first end face and a second end face, the first end face is used for contacting with a limiting block, and a radially movable channel is reserved between the second end face and the flange for the inner bushing.

[0011] As a further scheme of the present application, the inner side of the inner bushing is provided with a first abutting face, the pull rod is provided with a second abutting face abutting with the first abutting face, the first abutting face and the second abutting face are tightly fitted, and the first abutting face and the second abutting face are both circumferential faces.

[0012] As a further scheme of the present application, the inner bushing is divided into at least three independent arc segments along the axial direction, and the arc segments are combined to form the outer thread groove.

[0013] As a further scheme of the present application, the inner bushing is made of wear-resistant alloy material.

[0014] An aircraft landing gear comprising the pull spring connecting mechanism as any one of the preceding claims, comprising: a landing gear body; an upper lock comprising two lock connecting rods, the connecting part is sleeved on the lock connecting rods through the through hole, and the two ends of the pull spring body are connected to the lock connecting rods through the two connecting assemblies respectively.

[0015] As a further scheme of the present application, the pull spring connecting mechanism is provided with at least two groups.

[0016] The present application has the following beneficial effects: the inner bushing is entirely sleeved in the inner circle of the pull spring body, the outer thread groove formed in the outer circumferential face of the inner bushing is engaged with the helical spring wire of the pull spring body, so that the axial tension of the end of the pull spring body can be transmitted through the multi-turn thread engagement face, and the bending hook structure prone to stress concentration in the traditional pull spring is fundamentally replaced; the outer bushing is sleeved in the outer circle of the pull spring body, and the pull spring body is radially clamped together with the inner bushing, so that the rigidity and stability of the connecting part are enhanced, and the pull spring body is prevented from being deformed and coming out of the outer thread groove of the inner bushing in the radial direction; in addition, the pull rod is arranged in the inner bushing, one end of the pull rod is provided with a radially extended limiting block, the limiting block and the outer bushing jointly form axial limiting for the inner bushing, so that the components are prevented from being loosened under dynamic load, and the connecting part at the other end of the pull rod is used for connecting the external lock connecting rod.

[0017] Through the cooperation of the above-mentioned components, the stress mode of the end part of the tension spring body is changed from the traditional local bending load of the hook to the uniform load along the thread engagement surface, which significantly reduces the stress concentration coefficient, so that the tension spring can effectively inhibit the initiation and propagation of fatigue cracks under high-amplitude alternating tensile load in the process of airplane landing and take-off, thereby greatly improving the connection reliability and the overall fatigue life of the tension spring, ensuring the continuous stability of the uplock function, and enhancing the safety of the airplane landing gear system. BRIEF DESCRIPTION OF DRAWINGS

[0018] The application will be further described below with reference to the drawings.

[0019] Figure 1 is a schematic diagram of the overall structure of the tension spring connecting mechanism of the application; Figure 2 is a partial structure sectional view of the tension spring connecting mechanism of the application; Figure 3 is another diagram of the partial structure sectional view of the tension spring connecting mechanism of the application; Figure 4 is an elevation view of the inner bushing of the tension spring connecting mechanism of the application; Figure 5 is a split side view of the inner bushing of the tension spring connecting mechanism of the application; Figure 6 is a schematic diagram of the overall structure of the airplane landing gear of the application.

[0020] Reference signs: 1, tension spring body; 2, connecting assembly; 21, inner bushing; 22, outer bushing; 23, pull rod; 211, outer thread groove; 231, limiting block; 232, connecting part; 232a, through hole; 221, flange; 212, first end face; 213, second end face; 214, movable channel; 215, first abutting surface; 233, second abutting surface; 216, arc segment; 3, landing gear body; 31, uplock; 311, lock connecting rod. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0022] Reference Figures 1-2The application discloses a tension spring connecting mechanism, which replaces the traditional tension spring used in an airplane landing gear, and comprises a tension spring body 1 and a connecting assembly 2 arranged at the end of the tension spring body 1. The connecting assembly 2 comprises an inner bushing 21 arranged in the inner circle of the tension spring body 1, an outer bushing 22 arranged in the outer circle of the tension spring body 1 and a pull rod 23 arranged in the inner bushing 21. The outer circumferential surface of the inner bushing 21 is provided with an outer thread groove 211, the helical spring wire of the tension spring body 1 is arranged in the outer thread groove 211, the inner bushing 21 and the outer bushing 22 jointly form radial clamping on the tension spring body 1, the side of the pull rod 23 towards the inside of the tension spring body 1 is provided with a radial extension limiting block 231, the limiting block 231 and the outer bushing 22 jointly form axial limiting on the inner bushing 21, and the other side of the pull rod 23 is provided with a connecting part 232 extending out of the outer bushing 22, which is used for connecting external structures.

[0023] Specifically, when assembling the mechanism, the inner bushing 21 is wholly arranged in the inner circle of the tension spring body 1, the outer thread groove 211 on the outer surface of the inner bushing 21 is engaged with the helical spring wire of the tension spring body 1, the pull rod 23 is inserted into the inner bushing 21, the limiting block 231 at one end of the pull rod 23 is in contact with one end of the inner bushing 21, the other end of the pull rod 23 extends out of the inner bushing 21, the outer bushing 22 is arranged on the outer circle of the tension spring body 1 from the extending end of the pull rod 23 and jointly clamps the tension spring body 1 with the inner bushing 21, and the connecting part 232 of the pull rod 23 extends out of the outer bushing 22 and is used for connecting external structures.

[0024] Further, the inner bushing 21 is wholly arranged in the inner circle of the tension spring body 1, the outer thread groove 211 arranged on the outer circumferential surface of the inner bushing 21 is engaged with the helical spring wire of the tension spring body 1, the axial tension of the end of the tension spring body 1 is transmitted through the multi-turn thread engagement surface, the bending hook structure prone to stress concentration in the traditional tension spring is fundamentally replaced, the outer bushing 22 is arranged on the outer circle of the tension spring body 1 and jointly forms radial clamping on the tension spring body 1 with the inner bushing 21, the rigidity and stability of the connecting part 232 are enhanced, the tension spring body 1 is limited in the radial direction to prevent deformation and out of the outer thread groove 211 of the inner bushing 21, in addition, the pull rod 23 is arranged in the inner bushing 21, one end of the pull rod 23 is provided with the radial extension limiting block 231, the limiting block 231 and the outer bushing 22 jointly form axial limiting on the inner bushing 21, the connecting part 232 at the other end of the pull rod 23 is used for connecting the external lock connecting rod 311.

[0025] Through the cooperation of the above-mentioned components, the stress mode of the end part of the tension spring body 1 is changed from the traditional local bending load of the hook to the uniform load along the thread engagement surface, which significantly reduces the stress concentration coefficient, so that the tension spring can effectively inhibit the initiation and propagation of fatigue cracks under high-amplitude alternating tensile load in the process of airplane take-off and landing, thereby greatly improving the connection reliability and the overall fatigue life of the tension spring, ensuring the continuous stability of the uplock 31 function, and enhancing the safety of the airplane landing gear system.

[0026] Referring to Figures 1-4 Optionally, the external thread groove 211 is matched with the pitch and cross-sectional shape of the helical spring wire of the tension spring body 1.

[0027] In this embodiment, the external thread groove 211 is consistent with the shape of the helical spring wire, ensuring complete adhesion between the two, increasing the contact area, and making the tension more evenly transmitted to the inner bushing 21, avoiding excessive local stress.

[0028] Referring to Figures 1-3 Optionally, the connecting part 232 of the pull rod 23 is provided with a through hole 232a for connecting with the external structure, which is convenient for connecting with the shaft, rod or pin of the external structure.

[0029] Referring to Figures 1-3 Optionally, the end part of the outer bushing 22 has an inward and radially extending flange 221, and the two ends of the inner bushing 21 are provided with a first end face 212 and a second end face 213, the first end face 212 is used to contact with the limiting block 231, and the second end face 213 and the flange 221 are reserved with a radial movement channel 214 for the inner bushing 21.

[0030] In this embodiment, when the tension spring body 1 is pulled, the inner bushing 21 can move slightly in the radial direction within a certain range, adapting to the deformation of the tension spring body 1, avoiding the assembly stress and additional bending moment caused by complete rigid constraint, and improving the adaptability and reliability of long-term work of the mechanism.

[0031] Referring to Figure 3 Optionally, the inner side of the inner bushing 21 has a first abutting surface 215, and the pull rod 23 has a second abutting surface 233 abutting with the first abutting surface 215, the first abutting surface 215 and the second abutting surface 233 are closely fitted, and the first abutting surface 215 and the second abutting surface 233 are both circumferential surfaces.

[0032] In this embodiment, the force transmission between the pull rod 23 and the inner bushing 21 is realized through the uniform and large-area surface contact between the first abutting surface 215 and the second abutting surface 233, avoiding stress concentration and wear caused by point contact or line contact.

[0033] Referring to Figure 5Optionally, the inner sleeve 21 is axially cut into at least three independent arc segments 216, so that each arc segment 216 can be radially inserted into the inner ring of the tension spring body 1, and the arc segments 216 are combined to form the outer thread groove 211. Figure 5 As shown in the figure, three independent arc segments 216 are taken as an example, and the size of one arc segment is smaller than the inner diameter of the inner sleeve, so that the arc segment can enter the inside of the inner sleeve, facilitating the connection and installation between the inner sleeve and the tension spring body.

[0034] In this embodiment, because the helical spring wire of the tension spring body 1 matches the outer thread groove 211 on the inner sleeve 21, it is difficult to insert the inner sleeve 21 into the tension spring body 1 as a whole, and the segmented design enables the inner sleeve 21 to be axially entered into the tension spring body 1 and then installed radially, so that the helical spring wire of the tension spring body 1 is sleeved in the outer thread groove 211. When the last arc segment 216 is installed, there is no need to perform complex axial insertion operation, which greatly facilitates the installation and later maintenance and replacement in a space-limited environment, and under the constraint of the outer sleeve 22 and the tension spring body 1, the arc segments 216 can be reliably combined and bear as a whole, ensuring the connection strength and functional integrity.

[0035] Referring to Figure 1 Optionally, the connection assembly 2 is provided with two groups, and the two groups of connection assemblies 2 are connected to the two ends of the tension spring body 1.

[0036] In this embodiment, the same connection mode is adopted at the two ends of the tension spring body 1, so that the symmetric force is realized, and the balanced force at the two ends of the tension spring body 1 in the stretching process is ensured.

[0037] Optionally, the inner sleeve 21 is made of wear-resistant alloy material, such as high-strength steel or titanium alloy, which can withstand the high-frequency micro-motion and friction between the tension spring body 1 and the inner sleeve 21, reducing wear and fatigue damage.

[0038] Referring to Figures 1-6 The aircraft landing gear of the embodiment of the present application includes the tension spring connecting mechanism of any of the foregoing, which includes a landing gear body 3 and an upper lock 31 including two lock connecting rods 311, and the connecting portions 232 are sleeved on the lock connecting rods 311 through the through holes 232a, and the two ends of the tension spring body 1 are connected to the lock connecting rods 311 through the two connecting portions 232, respectively.

[0039] In this embodiment, the outer thread groove 211 of the inner bushing 21 is engaged with the helical spring wire of the pull spring body 1, and the radial clamping is realized by cooperating with the outer bushing 22, which replaces the traditional pull spring connecting mechanism with a hook connection mode, thereby effectively eliminating the stress concentration at the end of the pull spring body 1, and providing stable and continuous tension for the lock connecting rod 311 through the pull spring connecting mechanism, helping the lock connecting rod 311 to pass through the dead point and stabilize in the locking position, significantly improving the fatigue life and anti-vibration performance of the pull spring body 1 connection, effectively avoiding the risk of functional failure of the upper lock 31 caused by pull spring fatigue fracture, and further enhancing the operation reliability and flight safety of the aircraft landing gear retraction system.

[0040] Referring to Figures 1-6 Optionally, the pull spring connecting mechanism is provided with at least two groups.

[0041] In this embodiment, the multiple groups of pull spring connecting mechanisms work in parallel to provide redundant tension, so that even if one group fails, the remaining pull spring connecting mechanisms can still provide tension to the lock connecting rod 311.

[0042] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, and a particular orientation configuration and operation, therefore, it cannot be understood as a limitation on the present application. In addition, "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0043] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" and the like should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the scope of the present application. Any equivalent changes and improvements made within the scope of the present application shall still belong to the patent scope of the present application.

Claims

1. A tension spring connection mechanism, characterized in that, include: The tension spring body (1) and the connecting assembly (2) disposed at the end of the tension spring body (1); The connecting assembly (2) includes an inner bushing (21) fitted inside the inner ring of the tension spring body (1), an outer bushing (22) fitted outside the outer ring of the tension spring body (1), and a pull rod (23) disposed inside the inner bushing (21). The inner bushing (21) has an external threaded groove (211) on its outer circumferential surface. The helical spring wire of the tension spring body (1) is sleeved in the external threaded groove (211). The inner bushing (21) and the outer bushing (22) together form a radial clamping on the tension spring body (1). The pull rod (23) has a radially extended limiting block (231) on one side facing the inside of the tension spring body (1). The limiting block (231) and the outer bushing (22) together form an axial limiting on the inner bushing (21). The other side of the pull rod (23) has a connecting part (232) that extends axially out of the outer bushing (22). The connecting part (232) is used to connect to the external structure.

2. The tension spring connecting mechanism according to claim 1, characterized in that, The external thread groove (211) matches the pitch and cross-sectional shape of the helical spring wire of the tension spring body (1).

3. The tension spring connecting mechanism according to claim 2, characterized in that, Each of the connecting parts (232) of the tie rod (23) is provided with through holes (232a) for connecting with external structures.

4. The tension spring connecting mechanism according to claim 3, characterized in that, The connecting component (2) is provided in two sets, and the two sets of connecting components (2) are respectively connected to the two ends of the tension spring body (1).

5. The tension spring connecting mechanism according to claim 4, characterized in that, The outer bushing (22) has an inwardly extending flange (221) at its end. The inner bushing (21) has a first end face (212) and a second end face (213) at both ends. The first end face (212) is used to contact the limiting block (231). A radial movement channel (214) for the inner bushing (21) is reserved between the second end face (213) and the flange (221).

6. The tension spring connecting mechanism according to claim 5, characterized in that, The inner liner (21) has a first contact surface (215) on its inner side, and the pull rod (23) has a second contact surface (233) that abuts against the first contact surface (215). The first contact surface (215) and the second contact surface (233) fit tightly together. Both the first contact surface (215) and the second contact surface (233) are circumferential surfaces.

7. The tension spring connecting mechanism according to claim 6, characterized in that, The inner bushing (21) is divided into at least three independent arc segments (216) along the axial direction, and the arc segments (216) are joined together to form the external thread groove (211).

8. The tension spring connecting mechanism according to claim 7, characterized in that, The inner liner (21) is made of wear-resistant alloy material.

9. An aircraft landing gear comprising a tension spring connecting mechanism as described in any one of claims 3-8, characterized in that, include: Landing gear body (3); The upper lock (31) includes two locking rods (311), and the connecting part (232) is sleeved on the locking rod (311) through the through hole (232a). The two ends of the tension spring body (1) are respectively connected to the locking rod (311) through two connecting components (2).

10. The aircraft landing gear according to claim 9, characterized in that, The tension spring connection mechanism is provided in at least two sets.

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