Aero-engine combustion chamber front support bolt fastening structure

Abstract

This invention discloses a fastening structure for the front support bolt of an aero-engine combustor, including a bolt, a positioning sleeve, and a lock nut. The positioning sleeve is equipped with an upper anti-rotation component and a lower anti-rotation component to prevent the lock nut from rotating after it is fitted onto the bottom of the cylinder. As the lock nut is gradually fitted onto the bottom of the positioning sleeve, the actuator of the lower anti-rotation component is lifted. When the combustor casing mates with the front support, the combustor casing presses down on the upper anti-rotation component, causing its actuator to press down as well. The upper and lower anti-rotation components prevent the lock nut from rotating. After the combustor casing mates with the front support, the bolt is inserted from the combustor casing side and connected to the positioning sleeve and lock nut bolt, thus fastening the front support. This invention is suitable for fastening connections in confined spaces, and the non-threaded connection between the lock nut and the positioning sleeve avoids damage to the lock nut and positioning sleeve, enabling non-destructive disassembly.

Description

Technical Field

[0001] This invention relates to a fastening structure for the front support bolts of an aero-engine combustion chamber, belonging to the field of aero-engine assembly technology. Background Technology

[0002] Aerospace products often contain many confined or even enclosed spaces, where space constraints often prevent the access of tools like wrenches. For example, the front support cap of the combustion chamber flame tube in an aero-engine requires external bolt installation, but internal nut tightening is impossible, making standard bolt and nut fasteners unsuitable. Instead, methods like welding or riveting bracket nuts are used to pre-fix the nuts to the parts to be assembled, ultimately tightening the bolts after assembly to achieve a secure connection. However, replacing these welded or riveted bracket nuts requires mechanical force to remove the existing welds or rivets, making replacement inconvenient and inevitably causing significant damage to the parts each time. Another method is to use self-locking nuts, but these nuts deform after each assembly or disassembly, reducing or eliminating their locking torque and leading to nut failure.

[0003] To solve the above problems, the prior art proposes a solution that connects a nut and a threaded sleeve, and then connects a bolt to the nut. The tightening torque of the bolt and nut is controlled to be less than the tightening torque of the lock nut and the threaded sleeve. The pitch of the first reverse thread of the threaded sleeve is greater than the pitch of the first thread of the bolt. At the moment the bolt loosens, the nut is locked by the first reverse thread of the threaded sleeve, and the bolt will loosen first to achieve the purpose of disassembling the bolt smoothly.

[0004] When the bolt is disassembled, the second reverse thread of the nut and the first reverse thread of the sleeve in the above-mentioned fastening structure interact with each other, causing the nut to be locked. However, this method is prone to damage to the second reverse thread of the nut and the first reverse thread of the sleeve. Summary of the Invention

[0005] The purpose of this invention is to provide a fastening structure for the front support bolt of an aero-engine combustion chamber. This structure is suitable for fastening connections in confined spaces, and the lock nut and the positioning sleeve are connected by a non-threaded connection, which can avoid damage to the lock nut and the positioning sleeve and achieve non-destructive disassembly.

[0006] The technical solution adopted in this invention is as follows:

[0007] A fastening structure for the front support bolt of an aero-engine combustion chamber includes a bolt, a positioning sleeve, and a lock nut;

[0008] The positioning sleeve includes a cylinder and a square groove fixedly disposed at the top of the cylinder. A countersunk hole matching the square groove and a screw hole for the cylinder to pass through are provided on the front support.

[0009] Vertical and horizontal grooves are connected and formed on the two side walls at the bottom of the cylinder; and a slot is formed on the cylinder wall below the horizontal groove, with insertion holes that communicate with the horizontal groove and the bottom of the cylinder respectively above and below the slot; two through holes are also vertically formed on the side wall of the cylinder, corresponding to the insertion holes on the corresponding side; and the insertion holes and through holes are all located on the front side of the tail end of the horizontal groove.

[0010] Two insertable guide posts are provided inside the lock nut and can slide along the corresponding side vertical groove and horizontal groove. The lock nut is sleeved on the bottom end of the cylinder and connected to the cylinder through the guide posts. After the lock nut is sleeved on the bottom end of the cylinder, the side wall of the guide post abuts against the side wall of the end of the horizontal groove.

[0011] Two guide blocks are also provided on the inner wall of the lock nut located below the guide post. The top surface of the guide blocks forms a guide slope that gradually slopes downward from the head end to the tail end of the transverse groove.

[0012] The positioning sleeve also includes an upper anti-rotation component and a lower anti-rotation component to prevent the lock nut from rotating after it is fitted onto the bottom end of the cylinder; the upper anti-rotation component is installed in the square groove and the cylinder and the actuator can be raised and lowered relative to the through hole, and the lower anti-rotation component is installed in the groove and the actuator can be raised and lowered relative to the insertion hole.

[0013] As the lock nut is gradually fitted onto the bottom end of the cylinder under the action of the guide post, the guide block rotates with the lock nut. When the side wall of the guide post and the side wall of the end of the transverse groove are about to come into contact, the actuator of the lower anti-rotation component is pushed upward along the insertion hole and extended into the transverse groove under the action of the guide slope. When the combustion chamber casing is docked with the front support, the combustion chamber casing presses down on the upper anti-rotation component, so that the actuator of the upper anti-rotation component is inserted into the transverse groove along the through hole.

[0014] After the combustion chamber casing is connected to the front support, the bolt is inserted from the side of the combustion chamber casing, passes through the cylinder, and extends into the lock nut. The bolt is rotated to make the bolt and the lock nut threaded together to achieve the fastening of the front support.

[0015] Preferably, the upper anti-rotation component includes two round-headed columns, which are inserted into the corresponding through holes on the cylinder, and a spring is sleeved on the column located between the cylinder and the round head of the column.

[0016] Preferably, the lower anti-rotation component includes a lifting column disposed in the slot, with both ends of the lifting column extending into the upper and lower insertion holes respectively, and the bottom end of the lifting column extending to the bottom of the cylinder; a guide plate matching the slot is disposed on the lifting column, and a spring is disposed on the lifting column above the guide plate.

[0017] Preferably, the cylinder is also provided with threads in the same direction as the inner wall of the lock nut, and the bolt is also threadedly connected to the cylinder.

[0018] Preferably, the bottom end of the lock nut is in a retracted state, and the tail end of the screw is threadedly connected to the bottom end of the lock nut.

[0019] Preferably, the diameter of the tail end of the bolt is smaller than the diameter of the rod body inside the cylinder.

[0020] Preferably, the bottom end of the round-headed column has a spherical structure.

[0021] Preferably, both ends of the lifting column have a spherical structure.

[0022] The beneficial effects of this invention are as follows:

[0023] The lock nut and the positioning sleeve are connected by a non-threaded connection. At the same time, the lock nut is prevented from rotating by embedding the positioning sleeve into the countersunk hole. The upper and lower anti-rotation components prevent the nut from rotating after it is assembled onto the positioning sleeve. This allows the front support to be fastened to the combustion chamber casing with bolts. This can meet the fastening requirements of a narrow and confined space and can achieve non-destructive disassembly. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an aircraft engine;

[0025] Figure 2 This is a schematic diagram of the combustion chamber of an aircraft engine;

[0026] Figure 3 This is a cross-sectional view of the fastening structure;

[0027] Figure 4 Top view of the positioning sleeve;

[0028] Figure 5 A schematic diagram of the structure at the positioning sleeve and lock nut when the guide post is screwed into the head end of the horizontal groove;

[0029] Figure 6 This is a schematic diagram of the structure at the positioning sleeve and lock nut after the guide post is screwed into the end of the horizontal groove.

[0030] The meanings of the main reference numerals in the figure are as follows:

[0031] 10. Fan;

[0032] 20. Air compressor;

[0033] 30. Combustion chamber; 31. Flame tube; 31a. Flame tube head; 32. Fuel nozzle; 32a. Nozzle head; 33. Combustion chamber casing; 33a. Casing mounting base; 34. Diffuser; 35. Front support; 35a. Front support boss; 35b. Countersunk hole.

[0034] 40. Turbine;

[0035] 50. Bolts;

[0036] 60. Positioning sleeve; 61. Cylinder; 62. Square groove; 63. Vertical groove; 64. Horizontal groove; 65. Groove opening; 66. Insertion hole; 67. Lifting column; 68. Guide plate; 69. Spring 2; 610. Through hole; 611. Round head column; 612. Spring 1.

[0037] 70. Lock nut, 71. Guide post, 72. Guide block, 73. Guide slope. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] refer to Figure 1 As shown, the aero engine consists of components such as compressor 20, combustion chamber 30 and turbine 40. The compressor 20 compresses air, which is then burned in the combustion chamber 30 to do work on the turbine 40, converting the chemical energy of the fuel into the mechanical energy of the turbine 40. The turbine 40 exhausts the combustion gases and drives the fan 10 to generate thrust.

[0040] Figure 2 This is a schematic diagram of the combustion chamber of an aircraft engine. (Reference) Figure 2 As shown, the combustion chamber 30 mainly consists of a flame tube 31, a fuel nozzle 32, a combustion chamber casing 33, and a diffuser 34. The compressed airflow from the compressor 20 is decelerated and diffused by the diffuser 34 before entering the flame tube 31 and mixing with the fuel injected by the fuel nozzle 32 for combustion. The fuel nozzle 32 is mounted on the combustion chamber casing 33, with its nozzle head 32a extending into the flame tube head 31a to inject fuel. The entire flame tube 31 is mounted and connected to the combustion chamber casing 33 via a front support 35. Since the combustion chamber 30 is a closed annular cavity with limited space, and the flame tube 31 is connected to the front support 35, tightening of nuts and other fasteners within the combustion chamber casing 33 is impossible after the combustion chamber casing 33 is pushed in.

[0041] This embodiment provides a fastening structure for the front support bolts of an aero-engine combustion chamber, which can meet the fastening requirements of a confined space. See [link / reference]. Figure 3 As shown, it includes bolt 50, positioning sleeve 60, and lock nut 70; as Figure 4 As shown, the positioning sleeve 60 includes a cylinder 61 and a square groove 62 fixedly disposed on the top of the cylinder 61. A countersunk hole 35b matching the square groove 62 and a screw hole for the cylinder 61 to pass through are provided on the front support boss 35a. The positioning sleeve 60 is stuck in the countersunk hole 35b of the front support boss 35a through the square groove 62 and cannot rotate relative to it.

[0042] After the cylinder 61 is inserted into the screw hole of the front support boss 35a, its bottom end extends below the front support boss 35a. Vertical grooves 63 and horizontal grooves 64 are correspondingly connected on the two side walls of the bottom end of the cylinder 61 located below the front support boss 35a. A slot 65 is opened on the cylinder wall of the cylinder 61 located below the horizontal groove 64. Insertion holes 66 are opened above and below the slot 65, respectively, and are connected to the horizontal groove 64 and the bottom end of the cylinder 61. The insertion holes 66 are located on the front side of the tail end of the horizontal groove 64. A lower anti-rotation component is provided in the slot 65. The lower anti-rotation component includes a lifting column 67 with spherical structure at both ends, which is set in the slot 65. The two ends of the lifting column 67 extend into the upper and lower insertion holes 66, respectively, and the bottom end of the lifting column 67 extends to the bottom of the cylinder 61. A guide plate 68 matching the slot 65 is provided on the lifting column 67, and a spring 69 is sleeved on the lifting column 67 located above the guide plate 68.

[0043] Two insertable guide posts 71 are provided inside the lock nut 70, which can slide along the corresponding side vertical groove 63 and horizontal groove 64. The lock nut 70 is sleeved on the bottom end of the cylinder 61 and connected to the cylinder 61 through the guide posts 71. After the lock nut 70 is sleeved on the bottom end of the cylinder 61, the side wall of the guide post 71 abuts against the side wall of the tail end of the horizontal groove 64. Two guide blocks 72 are also provided on the inner wall of the lock nut 70 located below the guide posts 71. The top surface of the guide block 72 forms a guide slope 73 that gradually slopes downward from the head end to the tail end of the horizontal groove 64.

[0044] The aforementioned lock nut 70 structure allows the lock nut 70 to be gradually fitted onto the bottom end of the cylinder 61 under the action of the guide post 71, and during the assembly process, such as Figure 5 , 6 As shown, the guide block 72 rotates with the lock nut 70. When the side wall of the guide post 71 and the tail end side wall of the transverse groove 64 are about to come into contact, the bottom end of the lifting post 67 is gradually lifted under the action of the guide slope 73, so that the top end of the lifting post 67 can be pushed up along the insertion hole 66 and extended into the transverse groove 64. The lifting post 67 limits the guide post 71 to prevent the lock nut 70 from rotating.

[0045] Meanwhile, two through holes 610 corresponding to the corresponding side insertion holes 66 are vertically opened on the side wall of the cylinder 61. The through holes 610 are also located on the front side of the tail end of the transverse groove 64 and on the rear side of the insertion hole 66. An upper anti-rotation assembly is also provided in the square groove 62 and the cylinder 61. The upper anti-rotation assembly includes two round-headed pillars 611 with spherical bottom ends. The two round-headed pillars 611 are inserted into the through holes 610 on the corresponding side of the cylinder 61, and a spring 612 is sleeved on the pillar between the cylinder 61 and the round heads of the round-headed pillars 611. Figure 3 , 5As shown in Figure 6, when the casing mounting seat 33a of the combustion chamber casing 33 mates with the front support boss 35a, the casing mounting seat 33a presses down the round head post 611, so that the round head post 611 is inserted into the transverse groove 64 along the through hole 610, and cooperates with the lifting post 67 to further limit the guide post 71, so as to prevent the lock nut 70 from rotating.

[0046] The diameter of the tail end of bolt 50 is smaller than the diameter of the rod body inside cylinder 61, and the bottom end of lock nut 70 is in a contracted state. Cylinder 61 has threads in the same direction as the inner wall of lock nut 70. After the casing mounting seat 33a of combustion chamber casing 33 is aligned with the front support boss 35a, bolt 50 is inserted from the casing mounting seat 33a side of combustion chamber casing 33. Then, the screw is rotated so that the screw is threadedly connected to positioning sleeve 60 and lock nut 70 in sequence, thereby fastening the front support boss 35a and casing mounting seat 33a. When disassembly is required, due to the action of the upper anti-rotation component and the lower anti-rotation component, lock nut 70 and positioning sleeve 60 can still maintain the assembled state. At this time, it is only necessary to rotate bolt 50 to unscrew it.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A fastening structure for the front support bolt of an aero-engine combustion chamber, comprising a bolt, a positioning sleeve, and a lock nut; characterized in that: The positioning sleeve includes a cylinder and a square groove fixedly disposed at the top of the cylinder. A countersunk hole matching the square groove and a screw hole for the cylinder to pass through are provided on the front support. Vertical and horizontal grooves are connected and formed on the two side walls at the bottom of the cylinder; and a slot is formed on the cylinder wall below the horizontal groove, with insertion holes that communicate with the horizontal groove and the bottom of the cylinder respectively above and below the slot; two through holes are also vertically formed on the side wall of the cylinder, corresponding to the insertion holes on the corresponding side; and the insertion holes and through holes are all located on the front side of the tail end of the horizontal groove. Two insertable guide posts are provided inside the lock nut and can slide along the corresponding side vertical groove and horizontal groove. The lock nut is sleeved on the bottom end of the cylinder and connected to the cylinder through the guide posts. After the lock nut is sleeved on the bottom end of the cylinder, the side wall of the guide post abuts against the side wall of the end of the horizontal groove. Two guide blocks are also provided on the inner wall of the lock nut located below the guide post. The top surface of the guide blocks forms a guide slope that gradually slopes downward from the head end to the tail end of the transverse groove. The positioning sleeve also includes an upper anti-rotation component and a lower anti-rotation component to prevent the lock nut from rotating after it is fitted onto the bottom end of the cylinder; the upper anti-rotation component is installed in the square groove and the cylinder and the actuator can be raised and lowered relative to the through hole, and the lower anti-rotation component is installed in the groove and the actuator can be raised and lowered relative to the insertion hole. As the lock nut is gradually fitted onto the bottom end of the cylinder under the action of the guide post, the guide block rotates with the lock nut. When the side wall of the guide post and the side wall of the end of the transverse groove are about to come into contact, the actuator of the lower anti-rotation component is pushed upward along the insertion hole and extended into the transverse groove under the action of the guide slope. When the combustion chamber casing is docked with the front support, the combustion chamber casing presses down on the upper anti-rotation component, so that the actuator of the upper anti-rotation component is inserted into the transverse groove along the through hole. After the combustion chamber casing is connected to the front support, the bolt is inserted from the side of the combustion chamber casing, passes through the cylinder, and extends into the lock nut. The bolt is rotated to make the bolt and the lock nut threaded together to achieve the fastening of the front support.

2. An aeroengine combustion chamber forward support bolt fastening structure according to claim 1, characterised in that, The aforementioned anti-rotation component includes two round-headed columns, which are inserted into the corresponding through holes on the sides of the cylinder, and a spring is sleeved on the column located between the cylinder and the round head of the column.

3. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 1, characterized in that, The lower anti-rotation component includes a lifting column disposed in the slot, with both ends of the lifting column extending into the upper and lower insertion holes respectively, and the bottom end of the lifting column extending to the bottom of the cylinder; a guide plate matching the slot is disposed on the lifting column, and a spring is disposed on the lifting column above the guide plate.

4. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 1, characterized in that, The cylinder is also provided with threads in the same direction as the inner wall of the lock nut, and the bolt is also threadedly connected to the cylinder.

5. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 1, characterized in that, The bottom end of the lock nut is in a retracted state, and the tail end of the screw is threadedly connected to the bottom end of the lock nut.

6. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 1, characterized in that, The diameter of the tail end of the bolt is smaller than the diameter of the rod body inside the cylinder where the bolt is located.

7. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 2, characterized in that, The bottom of the round-headed column has a spherical structure.

8. The fastening structure for the front support bolt of an aero-engine combustion chamber according to claim 3, characterized in that, Both ends of the aforementioned lifting column have a spherical structure.

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