Primary landing gear emergency disconnect safety device

Abstract

The application discloses an emergency disconnecting safety device of a main landing gear and belongs to the technical field of disconnecting safety devices. The device comprises a rotating shaft pin, a pin shaft core, a shaft pin nut, a sealing cover and an anti-disengagement assembly. An annular groove is arranged on the shaft pin nut. The sealing cover limits the anti-disengagement assembly in the annular groove, and the sealing cover is connected with the shaft pin nut. The anti-disengagement assembly comprises an anti-disengagement snap ring and a locking ring. A clamping key is arranged on the anti-disengagement snap ring. A notch is arranged at a corresponding position of the shaft pin nut. A gap is arranged between the clamping key and the outer circumferential surface of the anti-disengagement snap ring. A positioning groove for positioning the locking ring is arranged on the inner wall of the shaft pin nut. The anti-disengagement assembly can prevent the shaft pin nut from rotating and avoid the loosening of the shaft pin nut, thereby ensuring that the safety device is stably installed between the main landing gear and the wing. The safety device can not only meet the requirement of stable positioning, but also meet the bearing function under normal load design of the landing gear and the emergency disconnecting function under overload conditions.

Description

Technical Field

[0001] The invention relates to an emergency disconnection safety device for a main landing gear, belonging to the technical field of disconnection safety devices. Background Art

[0002] In addition to using aerodynamics to provide lift for the aircraft, the wings of civil airliners also house the aircraft's fuel tanks. The aircraft's main landing gear is located on both sides of the wings close to the fuselage and below the aircraft's fuel tanks. Various extreme situations need to be considered when designing the aircraft. During landing, if the load is too heavy, the main landing gear may puncture the fuel tank, causing an explosion and leading to a devastating aviation disaster.

[0003] With the continuous advancement of aviation technology and the continuous improvement of aviation safety requirements, aircraft landing gear emergency separation technology has also been further researched and developed. The basic principle of emergency separation technology is that when the landing gear pin bearing is subjected to a pressure exceeding the design threshold, the emergency separation safety pin can be separated in time, and the landing gear can be abandoned to prevent the landing gear from puncturing the fuel tank and causing the fuel tank to rupture.

[0004] How to ensure that the emergency disconnect pin can accurately disconnect near the designed disconnection threshold, that is, "it should not disconnect when it should not disconnect, and it must disconnect when it should disconnect", to ensure that the emergency disconnect pin can not only transmit the load during normal take-off and landing, but also can promptly abandon the landing gear in the event of an overload landing. Existing emergency disconnect pins, such as solid pins, often have poor disconnection effects and lack the function of accurate disconnection, which will cause the wing tank to be damaged before the main landing gear, resulting in a fire risk and endangering passenger safety. Of course, there are also some hollow pins, but the existing hollow pins have a uniform wall thickness, and the disconnection position is uncertain, and the disconnection area cannot be clearly defined; in addition, the ends of the existing safety pins are mostly locked by nuts, which may loosen. Therefore, it is urgent to improve the existing emergency disconnect pins so that the safety pins can be stably positioned and accurately disconnected in an emergency. Summary of the Invention

[0005] The present invention aims to solve the deficiencies in the prior art and provides a main landing gear emergency disconnection safety device.

[0006] The present invention solves the above-mentioned technical problem with the following technical solution: a main landing gear emergency disconnection safety device, comprising a rotating shaft pin, a pin core, a shaft pin nut, and a sealing cover; the rotating shaft pin is hollow inside, and the inner wall of the rotating shaft pin is provided with a first weakening groove and a second weakening groove, and an inwardly convex thickened portion provided between the first weakening groove and the second weakening groove; the rotating shaft pin includes a threaded end connected to the shaft pin nut and a plate end provided with a pin end plate;

[0007] The pin shaft core is installed on the rotating shaft pin, and the inner end of the pin shaft core is inserted into the rotating shaft pin from the plate end side, and the length of the pin shaft core is smaller than the length of the rotating shaft pin;

[0008] It also includes an anti-slip assembly for preventing the shaft pin nut from loosening, an annular groove for positioning the anti-slip assembly is provided on the shaft pin nut, the inner plug of the sealing cover is inserted into the shaft pin from the threaded end side, the sealing end plate of the sealing cover limits the anti-slip assembly in the annular groove, and the sealing end plate of the sealing cover is connected to the shaft pin nut;

[0009] The anti-slip assembly includes an anti-slip snap ring and a locking ring. At least one key is provided on the outer circumference of the anti-slip snap ring. A groove adapted to the key is provided at the corresponding position of the outer end of the shaft pin nut. A gap for accommodating the locking ring is provided between the key and the outer circumference of the anti-slip snap ring. A positioning groove for positioning the locking ring is provided on the inner wall of the shaft pin nut. An internal spline is provided on the inner wall of the anti-slip snap ring. An external spline adapted to the internal spline is provided on the rotating shaft pin.

[0010] The beneficial effects of the present invention are as follows: a hollow weakening treatment is performed inside the rotating shaft pin, a first weak groove and a second weak groove are respectively provided in corresponding sections of the inner wall of the pin, and a thickened section, i.e., an inwardly convex thickened portion, is provided between the first weak groove and the second weak groove to improve the strength, thereby meeting the load requirements of the safety device under normal circumstances, and the first weak groove and the second weak groove on both sides clearly define the disconnection position of the safety device under emergency circumstances; the shaft pin nut is threadedly installed at the threaded end of the rotating shaft pin, an anti-slipping snap ring is installed in the annular groove, the key is engaged with the notch, and then a locking ring is installed to position the anti-slipping snap ring on the shaft pin The nut is then mounted with a sealing cover, which can press the anti-slip assembly into the annular groove. The external spline is set on the shaft pin, such as on the external thread of the shaft pin. After the shaft pin nut is screwed into the shaft pin, the anti-slip retaining ring is installed into the shaft pin nut. The internal spline of the anti-slip retaining ring engages with the external spline of the shaft pin, which can prevent the anti-slip retaining ring and the shaft pin from rotating relative to each other. At the same time, the key of the anti-slip retaining ring is embedded in the notch of the shaft pin nut, preventing the anti-slip retaining ring and the shaft pin nut from rotating relative to each other, thereby ensuring that the shaft pin nut and the shaft pin will not rotate, thereby preventing the thread from loosening. The anti-slip assembly can prevent the nut from rotating, avoid the shaft pin nut from loosening, and ensure that the safety device is stably installed between the main landing gear and the wing. The safety device is installed between the main landing gear joint and the wing joint, which not only meets the requirements of stable positioning of the safety device, but also meets the load-bearing function within the normal load design of the landing gear and the emergency disconnection function under overload conditions. Under normal operating conditions, the safety device has sufficient strength and rigidity to ensure the transmission of ground loads and maintain the integrity of the aircraft structure; under vertical load overload conditions, the safety device will be accurately and timely cut off when the load reaches the designed breakaway load to ensure that the overload load cannot be transmitted to the wing, thereby protecting the wing fuel tank structure.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the rotating shaft pin is provided with a rotation-stopping protrusion, and the rotation-stopping protrusion is provided with a rotation-stopping plane.

[0013] The beneficial effect of adopting the above further solution is that after the shaft pin is assembled, the anti-rotation plane of the anti-rotation protrusion on the shaft pin can contact the body of the wing joint, thereby preventing the shaft pin from rotating relative to the body of the wing.

[0014] Furthermore, the locking ring is an open structure, and is provided with a hook end and a hookless end, and one of the notches is provided with a locking ring groove for positioning the hook end.

[0015] The beneficial effect of adopting the above-mentioned further scheme is that when installing the locking ring, the hookless end can be slowly inserted from the positioning groove until the locking ring is completely positioned in the positioning groove, and then the hook end can be buckled into the locking ring groove to complete the installation of the locking ring. The locking ring is stably positioned and easy to install and disassemble.

[0016] Furthermore, the wall thickness of the inwardly convex thickened section is greater than the wall thickness of other positions of the rotating shaft pin.

[0017] The beneficial effect of adopting the above further solution is that the pivot pin adopts a thickened middle portion design to improve the strength and ensure the load-bearing function of the safety device under normal load.

[0018] Furthermore, a main landing gear bearing is provided between the rotating shaft pin and the main landing gear joint, the first weak groove and the second weak groove are respectively arranged at positions corresponding to both sides of the main landing gear bearing, and the rotating shaft pin is connected to the wing through a joint bushing.

[0019] The beneficial effect of adopting the above-mentioned further scheme is that the main lifting bearing and the joint bushing can meet the requirements of retraction and extension of the main landing gear. The first weak groove and the second weak groove on both sides clearly define the disconnection position of the safety device in an emergency situation. The middle of the first weak groove corresponds to the left position of the main lifting bearing, and the middle of the second weak groove corresponds to the right position of the main lifting bearing, ensuring that the disconnection position of the safety device can be constrained to the two sides of the bearing, that is, the area with maximum shear force, when overloaded, so that the safety device can accurately and timely cut off the connection between the main landing gear and the wing when the designed disconnection load is reached.

[0020] Furthermore, a pin bushing is sleeved on the outer side of the rotating shaft pin, and the pin bushing is located between the shaft pin nut and the main bearing.

[0021] The beneficial effect of adopting the above further solution is that the pin bushing can play a role in preventing wear. After assembly, the pin bushing and the raised flange on the pin bushing can play a role in limiting the main bearing and can be used to control the installation gap.

[0022] Furthermore, a washer is provided between the axle pin nut and the pin bushing.

[0023] The beneficial effect of adopting the above further solution is to protect the surface of the pin bushing from being scratched during the rotation and installation of the shaft pin nut, disperse the pressure of the shaft pin nut on the pin bushing, and avoid deformation or damage of the pin bushing component caused by excessive local pressure.

[0024] Furthermore, it also includes a first oiling mechanism for supplying oil to the main bearing, the first oiling mechanism includes a first oiling nozzle and a first oil supply hole radially arranged on the rotating shaft pin, the first oiling nozzle is arranged on the pin shaft core, and a first oil supply pipeline for connecting the first oiling nozzle and the first oil supply hole is provided in the pin shaft core; the joint bushing includes a second joint bushing, and also includes a second oiling mechanism for supplying oil to the second joint bushing, the second oiling mechanism includes a second oiling nozzle and a second oil supply hole radially arranged on the rotating shaft pin, the second oiling nozzle is arranged on the pin shaft core, and a second oil supply pipeline for connecting the second oiling nozzle and the second oil supply hole is provided in the pin shaft core.

[0025] The beneficial effect of adopting the above-mentioned further solution is that, through two independent lubrication channels in the pin core, external lubrication is provided to the rotating pair between the pivot pin and the main start bearing and the two bushings in the front ear of the pivot pin and wing joint, respectively, thereby reducing the risk of wear and structural abrasion of the kinematic pair. The oil filling mechanism can be directly filled through the oil filling nozzle, and the lubricating oil filling operation is convenient. The filled lubricating oil can directly act on the space between the main start bearing and the pivot pin, and between the joint bushing and the pivot pin. Lubricating oil is supplied to the main start bearing and the joint bushing from the inside of the safety device. The lubricating oil can be stored in the oil supply line, improving the lubrication effect between the main landing gear joint, the main start bearing, the joint bushing and the pivot pin, and extending the service life of the main start bearing, the joint bushing and other components.

[0026] Furthermore, the first oil supply pipeline includes a first axial channel axially arranged on the pin core, a first radial channel radially arranged on the pin core, and a first annular channel arranged on the outer circumferential surface of the pin core, one end of the first axial channel is connected to the first oil injection nozzle, and the other end of the first radial channel is connected to the first axial channel and the first annular channel; the second oil supply pipeline includes a second axial channel axially arranged on the pin core, a second radial channel radially arranged on the pin core, and a second annular channel arranged on the outer circumferential surface of the pin core, one end of the second axial channel is connected to the second oil injection nozzle, and the other end of the second radial channel is connected to the second axial channel and the second annular channel.

[0027] The beneficial effect of adopting this further solution is that an axial channel connected to the oil injection nozzle is provided within the pin core, which can guide the oil circuit to the corresponding oil supply point. The oil supply ring is provided on the outer surface of the pin core at the corresponding oil supply point. The axial channel is then connected to the oil supply ring through a radial channel to supply oil to the main bearing and joint bushing. The hollow area within the rotating shaft pin is fully utilized, and the pin core structure inserted into the rotating shaft pin is improved to meet the requirements of the oil supply line.

[0028] Furthermore, a sealing ring is provided between the pin shaft core and the inner wall of the rotating shaft pin, and the sealing ring is respectively arranged on both sides of the first ring channel and the second ring channel. A sealing ring groove for positioning the sealing ring is provided on the outer surface of the pin shaft core.

[0029] The beneficial effect of adopting the above-mentioned further scheme is that the sealing ring is located on both sides of the first ring channel, ensuring the sealing effect between the rotating shaft pin and the pin shaft core at the first ring channel, and avoiding leakage of lubricating oil at the first ring channel; the sealing ring is located on both sides of the second ring channel, ensuring the sealing effect between the rotating shaft pin and the pin shaft core at the second ring channel, and avoiding leakage of lubricating oil at the second ring channel.

[0030] Furthermore, an annular bulge is provided on the outer peripheral surface of the anti-dropping clamp, the outer diameter of the annular bulge is adapted to the inner wall of the annular groove, and the inner end of the clamping key is connected to the annular bulge.

[0031] The beneficial effect of adopting the above-mentioned further scheme is that, on the one hand, the cooperation between the annular bulge and the annular groove is conducive to the installation of the anti-slip retaining ring on the shaft pin nut, thereby preventing the anti-slip retaining ring from shaking; on the other hand, the step position of the annular bulge can limit the locking ring, ensuring that the locking ring is accurately installed in the positioning groove; in addition, the key is provided on the annular bulge, ensuring the gap between the key and the outer peripheral surface of the anti-slip retaining ring to meet the positioning and installation requirements of the locking ring.

[0032] Furthermore, the gap is smaller than the outer diameter of the locking ring, and at least one of the notch sides is provided with a mounting guide groove for guiding the locking ring into the positioning groove.

[0033] The beneficial effect of adopting the above further solution is that the hookless end of the locking ring can be inserted into the positioning groove under the guidance of the installation guide groove, and the gap is smaller than the outer diameter of the locking ring, which can ensure that the locking ring can be stably installed in the positioning groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the present invention;

[0035] Figure 2 This is a schematic diagram of the main structure of the present invention;

[0036] Figure 3 It is a right side structural schematic diagram of the present invention;

[0037] Figure 4 for Figure 3 Cross-section along the AA direction;

[0038] Figure 5 for Figure 3 Cross-section along the BB direction;

[0039] Figure 6 for Figure 3Cross-section along CC direction;

[0040] Figure 7 A schematic diagram of the three-dimensional structure of the present invention from another angle;

[0041] Figure 8 This is a schematic diagram of the explosion structure of the safety device of the present invention;

[0042] Figure 9 This is a diagram showing the use status of the safety device of the present invention;

[0043] In the figure, 1. rotating shaft pin; 101. first weak groove; 102. second weak groove; 103. inwardly convex thickened portion; 104. first oil supply hole; 105. second oil supply hole; 106. anti-rotation protrusion; 107. anti-rotation plane; 2. pin core; 201. first axial channel; 202. second axial channel; 203. first radial channel; 204. second radial channel; 205. first annular channel; 206. second annular channel; 207. sealing ring groove; 208. axial hole; 3. shaft pin nut; 301. notch; 302. mounting guide groove; 303. positioning groove; 304, annular groove; 305, nut ear plate; 4, sealing cover; 401, exhaust hole; 402, sealing groove; 403, covering ear plate; 5, anti-slip ring; 501, key; 502, ring protrusion; 503, gap; 504, locking ring groove; 6, locking ring; 601, hook end; 7, pin bushing; 8, washer; 9, sealing ring; 10, locking screw; 11, first oiling nozzle; 12, second oiling nozzle; 13, fastening bolt; 14, main landing gear joint; 15, main bearing; 16, wing joint; 17, first joint bushing; 18, second joint bushing. DETAILED DESCRIPTION

[0044] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0045] like Figures 1-9 As shown, a main landing gear emergency disconnect safety device includes a rotating shaft pin 1, a pin core 2, a pin nut 3 and a sealing cover 4; the rotating shaft pin 1 is hollow inside, and the inner wall of the rotating shaft pin 1 is provided with a first weakening groove 101 and a second weakening groove 102, and an inwardly convex thickened portion 103 disposed between the first weakening groove 101 and the second weakening groove 102; the rotating shaft pin 1 includes a threaded end connected to the pin nut 3 and a plate end provided with a pin end plate;

[0046] The pin core 2 is installed on the shaft pin 1, and the inner end of the pin core 2 is inserted into the shaft pin 1 from the plate end side. The length of the pin core 2 is smaller than the length of the shaft pin 1;

[0047] It also includes an anti-slip assembly for preventing the shaft pin nut 3 from loosening, an annular groove 304 for positioning the anti-slip assembly is provided on the shaft pin nut 3, the inner plug of the sealing cover 4 is inserted into the shaft pin 1 from the threaded end side, and the sealing end plate of the sealing cover 4 limits the anti-slip assembly in the annular groove 304, and the sealing end plate of the sealing cover 4 is connected to the shaft pin nut 3;

[0048] The anti-slip assembly includes an anti-slip snap ring 5 and a locking ring 6. At least one key 501 is provided on the outer circumference of the anti-slip snap ring 5. A groove 301 that matches the key 501 is provided at the corresponding position of the outer end of the shaft pin nut 3. A gap 503 for accommodating the locking ring 6 is provided between the key 501 and the outer circumference of the anti-slip snap ring 5. A positioning groove 303 for positioning the locking ring 6 is provided on the inner wall of the shaft pin nut 3. An internal spline is provided on the inner wall of the anti-slip snap ring 5, and an external spline that matches the internal spline is provided on the rotating shaft pin 1.

[0049] The external thread of the threaded end of the shaft pin 1 has an external spline, and the anti-slip snap ring 5 has an internal spline. After the shaft pin nut 3 is screwed into the shaft pin 1, the anti-slip snap ring 5 is installed into the shaft pin nut 3, so that the internal spline of the anti-slip snap ring 5 engages with the external spline of the shaft pin 1, preventing the anti-slip snap ring 5 and the shaft pin 1 from rotating relative to each other. At the same time, the key 501 of the anti-slip snap ring 5 is embedded in the notch 301 at the outer end of the shaft pin nut 3, preventing the anti-slip snap ring 5 and the shaft pin nut 3 from rotating relative to each other, thereby ensuring that the shaft pin nut 3 and the shaft pin 1 will not rotate and preventing the threads from loosening. In order to prevent the anti-slipping snap ring 5 from falling off along the axial direction, a 1 / 2 circle positioning groove 303 is provided inside the shaft pin nut 3. After the anti-slipping snap ring 5 is inserted into the shaft pin nut 3, a gap is provided between the key 501 and the outer peripheral surface of the anti-slipping snap ring 5 for accommodating the locking ring 6. The hookless end of the locking ring 6 is slowly inserted clockwise from the mounting guide groove 302 of the shaft pin nut 3, and finally the hooked end of the locking ring 6 is buckled into the semi-lunar groove of the key 501 of the anti-slipping snap ring 5. The elastic force of the locking ring 6 is used to buckle the anti-slipping snap ring 5 in the shaft pin nut 3, so that the entire anti-slipping assembly forms a mechanical lock with a good anti-loosening effect; the anti-slipping snap ring 5 and the locking ring 6 play a double locking role.

[0050] The locking ring 6 can specifically be a locking steel wire.

[0051] The rotating shaft pin 1 is provided with a rotation-stopping protrusion 106, which is arranged on the pin end plate, and a rotation-stopping flat surface 107. After the rotating shaft pin 1 is assembled, the rotation-stopping flat surface 107 of the rotation-stopping protrusion 106 on the rotating shaft pin 1 can contact the body of the wing joint, thereby preventing the rotating shaft pin 1 from rotating relative to the body of the wing joint.

[0052] The anti-rotation protrusion 106 or the pin end plate is provided with a threaded hole, the pin core 2 is provided with a shaft core protrusion, and the shaft core protrusion is provided with a mounting hole. The pin core 2 is connected to the anti-rotation protrusion 106 or the pin end plate by a fastening bolt 13. This can prevent the pin core 2 from rotating relative to the shaft pin 1 and also fix the pin core 2.

[0053] The locking ring 6 is an open structure, having a hook end 601 and a hookless end. One of the notches 301 is provided with a locking ring groove 504 for positioning the hook end 601. When installing the locking ring 6, the hookless end can be slowly inserted through the positioning groove 303 until the locking ring 6 is fully positioned within the positioning groove 303. The hook end 601 is then snapped into the locking ring groove 504 to complete the installation of the locking ring 6. This ensures stable positioning of the locking ring 6 and facilitates installation and removal.

[0054] The wall thickness of the inwardly convex thickened section is greater than the wall thickness of other positions of the rotating shaft pin 1. The rotating shaft pin adopts a mid-thickened design to improve strength and ensure the load-bearing function of the safety device under normal load.

[0055] A main landing gear bearing 15 is provided between the pivot pin 1 and the main landing gear joint 14. The first and second weakening grooves 101, 102 are respectively provided at positions corresponding to either side of the main landing gear bearing 15. The pivot pin 1 is connected to the wing joint 16 via a joint bushing. The main landing gear bearing 15 and the joint bushing both meet the requirements for retraction and extension of the main landing gear joint 14. The first and second weakening grooves 101, 102 on either side clearly define the disconnection position of the safety device in an emergency. The middle of the first weakening groove 101 corresponds to the left side of the main landing gear bearing 15, and the middle of the second weakening groove 102 corresponds to the right side of the main landing gear bearing 15. This ensures that in the event of an overload, the disconnection position of the safety device can be constrained to the areas of maximum shear force on both sides of the bearing, allowing the safety device to accurately and promptly sever the connection between the main landing gear and the wing when the designed disconnection load is reached.

[0056] The outer side of the rotating shaft pin 1 is also provided with a pin bushing 7, which is located between the shaft pin nut 3 and the main bearing 15. The pin bushing can play a role in preventing wear. After assembly, the pin bushing and the raised flange on the pin bushing can limit the main bearing and can be used to control the installation clearance.

[0057] The joint bushing includes a first joint bushing 17 , and the pin bushing 7 is sleeved between the first joint bushing 17 and the rotating shaft pin 1 .

[0058] The shaft pin 1 is provided with an external thread that is threadedly connected to the shaft pin nut 3 . The outer diameter of the shaft pin 1 where the external thread is located is smaller than the outer diameter of other parts of the shaft pin 1 .

[0059] A washer 8 is also provided between the pin nut 3 and the pin bushing 7. The surface of the pin bushing 7 is protected from being scratched when the pin nut 3 is rotated and installed, and the pressure of the pin nut 3 on the pin bushing 7 is dispersed to avoid deformation or damage of the pin bushing 7 caused by excessive local pressure.

[0060] It also includes a first oiling mechanism for supplying oil to the main starting bearing 15, the first oiling mechanism including a first oiling nozzle 11 and a first oil supply hole 104 radially arranged on the rotating shaft pin 1, the first oiling nozzle 11 is arranged on the pin core 2, and a first oil supply pipeline for connecting the first oiling nozzle 11 and the first oil supply hole 104 is provided in the pin core 2; the joint bushing includes a second joint bushing 18, and also includes a second oiling mechanism for supplying oil to the second joint bushing 18, the second oiling mechanism includes a second oiling nozzle 12 and a second oil supply hole 105 radially arranged on the rotating shaft pin 1, the second oiling nozzle 12 is arranged on the pin core 2, and a second oil supply pipeline for connecting the second oiling nozzle 12 and the second oil supply hole 105 is provided in the pin core 2. The existing safety pin has a long center bolt passing through its central axis. The length of the center bolt is greater than that of the main pin to meet the requirements of the positioning end cover. The center bolt is also locked by a nut, which may cause it to become loose. There is a bearing between the main landing gear joint 14 and the rotating shaft pin, and the bearing needs to be lubricated. However, the setting of the internal center bolt cannot supply oil to the bearing from the inside of the safety device. The oil supply from the outside is limited, and lubricating oil needs to be frequently added in a short period of time, and the filling process is cumbersome. The oil filling mechanism can be directly filled through the oil filling nozzle, and the lubricating oil filling operation is convenient. The added lubricating oil can directly act between the main landing gear bearing 15 and the rotating shaft pin and between the joint bushing and the rotating shaft pin. Lubricating oil is supplied to the main landing gear bearing 15 and the joint bushing from the inside of the safety device. The lubricating oil can be stored in the oil supply pipeline, thereby improving the lubrication effect between the main landing gear joint 14, the main landing gear bearing 15, the joint bushing and the safety device, and extending the service life of the main landing gear bearing 15, the joint bushing and the safety device.

[0061] The first oil supply pipeline includes a first axial channel 201 axially arranged on the pin core 2, a first radial channel 203 radially arranged on the pin core 2, and a first annular channel 205 arranged on the outer peripheral surface of the pin core 2, one end of the first axial channel 201 is connected to the first oiling nozzle 11, and the other end of the first radial channel 203 connected to the first axial channel 201 is connected to the first annular channel 205; the second oil supply pipeline includes a second axial channel 202 axially arranged on the pin core 2, a second radial channel 204 radially arranged on the pin core 2, and a second annular channel 206 arranged on the outer peripheral surface of the pin core 2, one end of the second axial channel 202 is connected to the second oiling nozzle 12, and the other end of the second radial channel 204 connected to the second axial channel 202 is connected to the second annular channel 206. An axial channel connected to the oil injection nozzle is provided in the pin core 2, which can guide the oil circuit to the position corresponding to the oil supply point. An oil supply ring is provided on the outer surface of the pin core 2 at the position corresponding to the oil supply point. Then, the axial channel is connected to the oil supply ring through a radial channel to supply oil to the main bearing 15 and the joint bushing. The hollow area in the rotating shaft pin 1 is fully utilized, and the structure of the pin core 2 inserted in the rotating shaft pin 1 is improved to meet the requirements of the oil supply pipeline. Figure 4 What is presented is Figure 3 Schematic diagram of the structure when the actual cross section is rotated counterclockwise to the horizontal state; Figure 5 What is presented is Figure 3 Schematic diagram of the structure in which the actual cross section is rotated clockwise to a horizontal state.

[0062] A sealing ring 9 is provided between the inner wall of the pin core 2 and the shaft pin 1. The sealing ring 9 is disposed on both sides of the first annular channel 205 and the second annular channel 206. A sealing ring groove 207 is provided on the outer surface of the pin core 2 for positioning the sealing ring 9. The sealing ring 9 is located on both sides of the first annular channel 205 to ensure a seal between the shaft pin 1 and the pin core 2 in the first annular channel 205, thereby preventing leakage of lubricating oil in the first annular channel 205. The sealing ring 9 is located on both sides of the second annular channel 206 to ensure a seal between the shaft pin 1 and the pin core 2 in the second annular channel 206, thereby preventing leakage of lubricating oil in the second annular channel 206.

[0063] The outer circumferential surface of the anti-falling snap ring 5 is provided with a ring protrusion 502, the outer diameter of the ring protrusion 502 is matched with the inner wall of the annular groove 304, and the inner end of the snap key 501 is connected with the ring protrusion 502. The ring protrusion 502 cooperates with the inner wall of the annular groove 304, which is beneficial to the installation of the anti-falling snap ring 5 in the shaft pin nut 3 and avoids the shaking of the anti-falling snap ring 5. On the other hand, the step position formed between the ring protrusion 502 and the anti-falling snap ring 5 can limit the locking ring 6, so as to ensure that the locking ring 6 is accurately installed in the positioning groove 303. In addition, the snap key 501 is arranged on the ring protrusion 502, so as to ensure the gap between the snap key 501 and the outer circumferential surface of the anti-falling snap ring 5, thereby meeting the positioning and installation requirements of the locking ring 6.

[0064] The gap between the snap key 501 and the outer circumferential surface of the anti-falling snap ring 5 is smaller than the outer diameter of the locking ring 6, and at least one of the notches 301 is provided with an installation guide groove 302 for guiding the locking ring 6 into the positioning groove 303. The unhooked end of the locking ring 6 can be inserted into the positioning groove 303 under the guidance of the installation guide groove 302, the gap is smaller than the outer diameter of the locking ring 6, and the locking ring 6 can be stably installed in the positioning groove 303.

[0065] The shaft pin core 2 is internally provided with an axial hole 208. The axial hole 208 can reduce the weight of the shaft pin core 2 and play a role in weight reduction.

[0066] The shaft pin nut 3 is provided with a nut ear plate 305, and the sealing end plate of the sealing cover 4 is connected with the nut ear plate 305 through a fastener. Specifically, the shaft pin nut 3 can be provided with a pair of nut ear plates 305, the sealing end plate of the sealing cover 4 is a pair of cover ear plates 403, and the cover ear plates 403 are connected with the nut ear plates 305 through fastening bolts 13. The fastening bolts 13 can also be provided with a fuse for anti-falling, and the fuse is locked through a small hole in the nut ear plate 305, so as to prevent the fastening bolts 13 from rotating.

[0067] The sealing cover 4 is provided with an exhaust hole 401, and the exhaust hole 401 is provided with a plugging. Specifically, the sealing cover 4 is internally provided with a locking sleeve, and the plugging adopts a locking screw 10. The air in the safety device can be discharged through the exhaust hole 401, which is convenient for the installation and positioning of the sealing cover 4. After the sealing cover 4 is installed, the exhaust hole 401 is closed by the plugging. A threaded hole is preformed in the exhaust hole 401, and then a locking sleeve is embedded. The exhaust hole plays a role in discharging the internal gas during the assembly of the sealing cover 4. After the installation is completed, the gasket 8 and the locking screw 10 can be screwed into the locking sleeve to block the exhaust hole 401.

[0068] A sealing ring 9 is provided between the sealing cover 4 and the rotating shaft pin 1, and a sealing groove 402 is provided on the sealing cover 4 for positioning the sealing ring 9. The sealing ring 9 can prevent water vapor in the air from entering the interior of the rotating shaft pin 1, thereby playing a role of sealing and anti-corrosion.

[0069] During installation: place the main landing gear joint 14 between the wing joints 16, specifically between the front ear of the wing joint and the rear ear of the wing joint. There are two second joint bushings 18 in the front ear of the wing joint, and a first joint bushing 17 in the rear ear of the wing joint. Align the hole on the main landing gear joint with the hole axis on the wing joint, install the shaft pin 1, washer 8 and shaft pin nut 3. After the shaft pin nut 3 is installed on the shaft pin 1, the anti-slip assembly can constrain the shaft pin nut 3 to prevent it from rotating, thereby preventing the shaft pin nut 3 from loosening. Specifically, the anti-slip snap ring 5 is embedded in the annular groove 304 of the shaft pin nut 3, and the key 501 is locked. Engage with the notch 301, then slowly insert the hookless end of the locking ring 6 into the positioning groove 303 from the side of the installation guide groove 302 until the locking ring 6 is completely positioned in the positioning groove 303, and buckle the hook end 601 of the locking ring 6 into the locking ring groove 504 of the key 501 to complete the installation of the locking ring 6. Then, the inner plug of the sealing cover 4 is inserted into the shaft pin 1, and the sealing cover end plate abuts the outer end surface of the locking ring 6. The sealing cover end plate is connected to the shaft pin nut 3 through the fastening bolt 13 to achieve the installation of the sealing cover 4. The pin core 2 is inserted into the shaft pin 1 from the plate end side. There is a shaft core protrusion on the outer end of the pin core 2, and the shaft core protrusion is connected to the anti-rotation protrusion 106 through the fastening bolt 13. The pin core 2 has an oil supply nozzle and an oil supply pipeline to supply oil and lubrication to the main bearing 15 and the joint bushing. In order to ensure that the separation of the rotating shaft pin 1 can be constrained to the two sides of the main bearing 15, that is, the area with the maximum shear force, when overloaded, the inner wall of the rotating shaft pin 1 is grooved in the corresponding sections to set corresponding weak areas, namely the first weak groove 101 and the second weak groove 102. The straight sections such as the bottom and top of the weak groove adopt R-angle transition to improve fatigue strength. The first weak groove 101 and the second weak groove 102 both include an R1 transition zone connecting the groove bottom and the inner convex thickened portion 103, and an R2 transition zone connecting the groove bottom and the outer side. R1 is smaller than R2, and R2 is close to the end side of the shaft pin. R2 is larger and the arc is gentler. In order to avoid tool interference during boring, the angle is less than 50 degrees, and RI is located in the middle position of the shaft pin. R2 is smaller. In order to ensure the length of the equal straight section of the first weak groove 101 and the second weak groove 102, the movable range of the main bearing 15 and both sides of the main bearing 15 can be kept in the equal straight section of the two weak grooves, so that the separation of the shaft pin 1 in the equal straight section ensures the accuracy of the separation load; at the same time, the two R1s near the middle position are smaller, which can also improve the product strength of the safety device. Under the action of vertical load, the safety pin is subjected to double shear force. The groove bottom diameter, i.e. the shear inner diameter, is designed according to the shear strength to ensure that the connection between the main landing gear and the wing is accurately and timely severed when the designed shear load is reached, avoiding the overload load from being transferred to the wing to protect the fuel tank structure of the wing and maintain the integrity of the aircraft. The middle part is thickened to improve the static strength. Under normal operating conditions, the shear safety device has sufficient strength and rigidity to ensure the transfer of load.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A main landing gear emergency disconnection safety device, comprising a rotating shaft pin (1), a pin core (2), a shaft pin nut (3) and a sealing cover (4); the rotating shaft pin (1) is hollow inside, and a first weak groove (101) and a second weak groove (102) are provided on the inner wall of the rotating shaft pin (1), and an inner convex thickened portion (103) is provided between the first weak groove (101) and the second weak groove (102); the rotating shaft pin (1) comprises a threaded end connected to the shaft pin nut (3) and a plate end provided with a pin end plate; The pin shaft core (2) is mounted on the rotating shaft pin (1), the inner end of the pin shaft core (2) is inserted into the rotating shaft pin (1) from the plate end side, and the length of the pin shaft core (2) is smaller than the length of the rotating shaft pin (1); It also includes an anti-slip assembly for preventing the shaft pin nut (3) from loosening, an annular groove (304) for positioning the anti-slip assembly is provided on the shaft pin nut (3), an inner plug of the sealing cover (4) is inserted into the shaft pin (1) from the threaded end side, and a sealing end plate of the sealing cover (4) limits the anti-slip assembly in the annular groove (304), and the sealing end plate of the sealing cover (4) is connected to the shaft pin nut (3); The anti-slip assembly comprises an anti-slip snap ring (5) and a locking ring (6), at least one key (501) is provided on the outer circumference of the anti-slip snap ring (5), a notch (301) adapted to the key (501) is provided at a corresponding position on the outer end of the shaft pin nut (3), a gap (503) for accommodating the locking ring (6) is provided between the key (501) and the outer circumference of the anti-slip snap ring (5), a positioning groove (303) for positioning the locking ring (6) is provided on the inner wall of the shaft pin nut (3), an inner spline is provided on the inner wall of the anti-slip snap ring (5), and an outer spline adapted to the inner spline is provided on the rotating shaft pin (1); The locking ring (6) is an open structure, and is provided with a hook end (601) and a hookless end, wherein one of the notches (301) is provided with a locking ring groove (504) for positioning the hook end (601).

2. The main landing gear emergency disconnect safety device according to claim 1, characterized in that: A rotation-stopping protrusion (106) is provided on the rotating shaft pin (1), the rotation-stopping protrusion (106) is arranged on the pin end plate, and a rotation-stopping plane (107) is provided on the rotation-stopping protrusion (106).

3. The main landing gear emergency disconnect safety device according to claim 1, characterized in that: The wall thickness of the inwardly convex thickened portion (103) is greater than the wall thickness of other positions of the rotating shaft pin (1).

4. The main landing gear emergency disconnect safety device according to any one of claims 1 to 3, characterized in that: A main landing gear bearing (15) is provided between the rotating shaft pin (1) and the main landing gear joint (14); the first weak groove (101) and the second weak groove (102) are respectively provided at positions corresponding to both sides of the main landing gear bearing (15); and the rotating shaft pin (1) is connected to the wing (16) via a joint bushing.

5. The main landing gear emergency disconnect safety device according to claim 4, characterized in that: A pin bushing (7) is also sleeved on the outer side of the rotating shaft pin (1), and the pin bushing (7) is located between the shaft pin nut (3) and the main bearing (15).

6. The main landing gear emergency disconnect safety device according to claim 4, characterized in that: The invention also includes a first oiling mechanism for supplying oil to the main starting bearing (15), the first oiling mechanism including a first oiling nozzle (11) and a first oil supply hole (104) radially arranged on the rotating shaft pin (1), the first oiling nozzle (11) being arranged on the pin shaft core (2), and a first oil supply pipeline for connecting the first oiling nozzle (11) and the first oil supply hole (104) being provided in the pin shaft core (2); the joint bushing including a second joint bushing (18), and also including a second oiling mechanism for supplying oil to the second joint bushing (18), the second oiling mechanism including a second oiling nozzle (12) and a second oil supply hole (105) radially arranged on the rotating shaft pin (1), the second oiling nozzle (12) being arranged on the pin shaft core (2), and a second oil supply pipeline for connecting the second oiling nozzle (12) and the second oil supply hole (105) being provided in the pin shaft core (2).

7. The main landing gear emergency disconnect safety device according to claim 6, characterized in that: The first oil supply pipeline comprises a first axial channel (201) axially arranged on the pin core (2), a first radial channel (203) radially arranged on the pin core (2), and a first annular channel (205) arranged on the outer peripheral surface of the pin core (2), one end of the first axial channel (201) is connected to the first oil injection nozzle (11), and the other end of the first radial channel (203) communicating with the first axial channel (201) is connected to the first annular channel (205); the second oil supply pipeline comprises a second axial channel (202) axially arranged on the pin core (2), a second radial channel (204) radially arranged on the pin core (2), and a second annular channel (206) arranged on the outer peripheral surface of the pin core (2), one end of the second axial channel (202) is connected to the second oil injection nozzle (12), and the other end of the second radial channel (204) communicating with the second axial channel (202) is connected to the second annular channel (206).

8. The main landing gear emergency disconnect safety device according to claim 7, characterized in that: A sealing ring (9) is provided between the pin shaft core (2) and the inner wall of the rotating shaft pin (1), and the sealing ring (9) is respectively arranged on both sides of the first annular channel (205) and the second annular channel (206). A sealing ring groove (207) for positioning the sealing ring (9) is provided on the outer surface of the pin shaft core (2).

9. The main landing gear emergency disconnect safety device according to any one of claims 1 to 3, characterized in that: An annular protrusion (502) is provided on the outer peripheral surface of the anti-slip retaining ring (5), the outer diameter of the annular protrusion (502) is adapted to the inner wall of the annular groove (304), and the inner end of the key (501) is connected to the annular protrusion (502); and / or the gap is smaller than the outer diameter of the locking ring (6), and at least one side of the notch (301) is provided with a mounting guide groove (302) for guiding the locking ring (6) into the positioning groove (303).

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