Method for balancing deformation of inner casing and protecting bolts

Abstract

The invention relates to a method for balancing deformation of an inner casing and protecting a bolt, belongs to the technical field of aero-engines, and particularly relates to a method for mounting a retainer on a mounting edge bolt at a matching position of a front section and a rear section of the inner casing, wrapping the bolt, changing the flow direction of high-temperature and high-air flow and protecting the mounting edge bolt at the matching position of the front section and the rear section of the inner casing. During assembling, the nut retainer is assembled on the windward side mounting edge of the inner casing, then the bolt retainer is assembled on the leeward side mounting edge, and finally the bolt is mounted. The protective ring is divided into a nut protective ring and a bolt protective ring, the whole protective ring is of an annular structure, the bolt protective ring is installed at the position of a nut of an installation side bolt, and the nut protective ring is installed at the position of a nut. The protective ring is designed and assembled to block pneumatic thermal shock of high-temperature and high-pressure airflow to the bolt and the nut, meanwhile, convective heat exchange between the airflow and the mounting edge is isolated, and the consistency of deformation of the inner casing matched with the mounting edge is balanced.

Description

Technical Field

[0001] The invention belongs to the technical field of aeroengines, and in particular relates to a method for balancing the deformation of an inner casing and protecting bolts. Background Art

[0002] The inner casing of the hot end part of an aircraft engine is in a high temperature area. During the operation of the engine, high temperature and high pressure air flows along the inner wall, causing continuous aerodynamic thermal shock to the front and rear sections of the inner casing. Figure 1 During the engine disassembly inspection, the inner casing may have problems such as sintering and breaking of the mounting side bolts, and the mismatch of the mounting sides at the matching position when the casing is reinstalled. This problem is caused by the mounting side directly bearing the high temperature and high pressure aerodynamic thermal shock, which leads to sintering of the bolts, and a large temperature difference between the windward side mounting side and the leeward side mounting side, resulting in inconsistent deformation, shear fracture of the bolts, and mismatch of the casing when reinstalled.

[0003] In case of inconsistent deformation of the receiver mounting edge, which leads to the problem of being unable to assemble, manual adjustment, bolt tightening, or auxiliary clamping with tooling and fixtures are generally used. However, this method will cause greater stress on the receiver mounting edge, which is not conducive to the long-term use of the receiver and will reduce reliability. In addition, there is also a method of adjusting the bolt hole type by machining, but this method is not conducive to subsequent maintenance. For receivers that cannot be adjusted, they need to be replaced, and the bolts also need to be replaced, resulting in increased maintenance costs. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for balancing the deformation of the inner casing and protecting the bolts. By arranging a protective ring assembled at the matching position of the installation edges of the front and rear sections of the inner casing, the situation of bolt sintering caused by the installation edge position directly bearing high temperature and high pressure aerodynamic thermal shock is improved. At the same time, the deformation inconsistency caused by the large temperature difference between the installation edge on the windward side and the installation edge on the leeward side, which causes shear breakage of the bolts and mismatch of the casing when reinstalled, is solved.

[0005] A method for balancing the deformation of an inner casing and protecting bolts, wherein a guard ring is installed on the mounting side bolts at the matching positions of the front and rear sections of the inner casing, so as to change the flow direction of high-temperature and high-airflow and protect the mounting side and the mounting side bolts and nuts at the matching positions of the front and rear sections of the inner casing.

[0006] The retaining ring is divided into a nut retaining ring (1) and a bolt retaining ring (2), both of which are in an annular structure as a whole. The bolt retaining ring (2) is installed at the nut position of the mounting side bolt, and the nut retaining ring (1) is installed at the nut position.

[0007] The nut retainer (1) comprises a front retainer (3) and a nut support plate (4), which wraps the nut of the mounting side bolt (10) inside; the cross-sectional structure of the front retainer (3) is a "concave" type, and a hole is opened on the front retainer (3) and the nut support plate (4) is assembled.

[0008] The nut support plate (4) is fixed to the front baffle retainer (3) by means of expansion.

[0009] During the assembly process of the nut support plate (4), the angle of the outer edge clamping part needs to be adjusted to prevent interference caused by assembly at the installation edge position of the inner casing.

[0010] The bolt retainer (2) comprises a lace washer (5) and a cut-out washer (6) which are arranged back to back and are fixed by welding.

[0011] The lace washer (5) wraps the windward side mounting edge (8) and the leeward side mounting edge (9) inside thereof, and has an "L"-shaped cross section, forming a lace structure as a whole. Each bolt hole on the mounting edge of the lace washer (5) is provided with a washer, and the middle portion is a ring tube structure.

[0012] The hollowing washer (6) wraps the nut of the mounting side bolt (10) inside it, and the cross section is "concave", wherein the front guard side is the mounting side, and each bolt hole of the front guard side is set as a washer, forming a lace structure as a whole; the rear guard side (7) corresponding to the front guard side is hollowed at each corresponding washer structure.

[0013] The assembly method of the retaining ring is as follows:

[0014] First, assemble the nut retainer (1) onto the mounting edge (8) on the windward side of the inner casing, then assemble the bolt retainer (2) onto the mounting edge (9) on the leeward side, and finally install the mounting edge bolts (10) and screw them into the nut retainer (1) to complete the assembly work.

[0015] The beneficial effects of the present invention are as follows: the present invention proposes a method for balancing the deformation of the inner casing and protecting the bolts, and a protective ring is provided to prevent the bolts and the mounting edge from directly bearing the high-temperature and high-pressure aerodynamic thermal shock, thereby improving the influence of the high-temperature and high-pressure aerodynamic thermal shock; at the same time, the temperature difference of the mounting edge at the matching position is reduced, so as to achieve the consistency of the deformation of the matching mounting edge of the inner casing, solve the problems of bolt shear fracture and mismatch of the casing when reinstalled, and at the same time achieve the effect of protecting the bolts.

[0016] This method has been effectively implemented on the engine, which has improved the sintering, fracture and deformation consistency of the inner casing connecting bolts and the installation edge shape at the matching position, ensuring the smooth reinstallation of engine components and saving the maintenance cost of the engine hot end components.

[0017] The invention method has been applied to engines and is expected to be applied to other types of engines in the future if the structural design and installation of components are reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram showing the continuous aerodynamic thermal shock formed by the front and rear sections of the inner casing;

[0019] Figure 2 is a schematic diagram of a nut retainer in the present invention;

[0020] Figure 3 is a schematic diagram of a nut support plate in the present invention;

[0021] Figure 4 is a schematic diagram of a bolt retainer in the present invention;

[0022] Figure 5 is a schematic diagram of a lace gasket in the present invention;

[0023] Figure 6 is a schematic diagram of the edge-cutting gasket in the present invention;

[0024] Figure 7 It is a schematic diagram of the assembly of the retaining ring in the present invention;

[0025] Figure 8 This is a protective effect diagram of the retaining ring in the present invention;

[0026] Figure 2-Figure 8 middle,

[0027] 1- nut guard ring, 2- bolt guard ring, 3- front baffle guard ring, 4- nut support plate, 5- lace washer, 6- digging washer, 7- rear baffle, 8- windward side installation edge, 9- leeward side installation edge, 10- installation side bolt. DETAILED DESCRIPTION

[0028] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0029] Through the study of the sintering, breakage and mismatch of bolts at the matching positions of the front and rear mounting edges of the aircraft engine inner casing, it was found that the root cause of the problem was that the mounting edge position was directly subjected to high temperature and high pressure aerodynamic thermal shock, and there was a large temperature difference between the windward mounting edge 8 and the leeward mounting edge 9.

[0030] like Figure 2-Figure 8As shown, in view of this situation, the present invention proposes a method for balancing the deformation of the inner casing and protecting the bolts, by designing and assembling a guard ring to block aerodynamic thermal shock and isolate convection heat exchange. The guard ring blocks the aerodynamic thermal shock of the high-temperature and high-pressure airflow on the bolts and nuts. At the same time, the ring tube section of the guard ring and the gasket forms a protective cover to isolate the airflow and the convection heat exchange of the installation edge, reduce the temperature difference between the installation edge 8 on the windward side and the installation edge 9 on the leeward side of the matching position, achieve the consistency of the deformation of the inner casing matching installation edge, and avoid sintering and fracture of the bolts. The details are as follows:

[0031] A retainer is installed on the mounting side bolt 10 at the matching position of the front and rear sections of the inner casing to change the direction of high-temperature and high-airflow to avoid continuous aerodynamic thermal shock at the matching position of the front and rear sections of the casing and protect the mounting side bolt 10 at the matching position of the front and rear sections of the inner casing. The retainer is divided into a nut retainer 1 and a bolt retainer 2, both of which are annular in structure as a whole; the bolt retainer 2 is installed at the nut position of the mounting side bolt 10 at the matching position of the front and rear sections of the inner casing, and the nut retainer 1 is installed at the locking nut position of the mounting side bolt 10 at the matching position of the front and rear sections of the inner casing.

[0032] The nut retainer 1 includes a front retainer 3 and a nut support plate 4. The cross-sectional structure of the front retainer 3 is a "concave" type. A hole is opened on the front retainer 3 and the nut support plate 4 is assembled. The nut support plate 4 is fixed to the front retainer 3 by expanding to form the nut retainer 1, and the locking nut of the mounting side bolt 10 is wrapped inside it. The flow direction of the high-temperature and high-pressure airflow is changed by the nut support plate 4, so that the high-temperature and high-pressure airflow is changed from flowing along the inner avoidance surface of the inner casing to flowing along the outer wall surface of the nut support plate 4, so as to avoid the high-temperature and high-pressure airflow directly acting on the matching position of the nut and the front and rear sections of the inner casing.

[0033] When assembling the nut support plate 4, it is necessary to adjust the angle of the outer edge clamping part to prevent interference when assembling at the installation edge of the inner casing.

[0034] The bolt guard 2 includes a lace washer 5 and a hollow washer 6 which are arranged back to back, and the lace washer 5 and the hollow washer 6 are welded. The cross section of the lace washer 5 is "L" shaped. In order to achieve the purpose of weight reduction, each bolt hole on the installation edge of the lace washer 5 is set as a washer, forming a lace structure as a whole, and the middle part is a ring tube structure. The cross section of the hollow washer 6 is "concave" shaped, also in order to achieve the purpose of weight reduction, wherein the front guard edge is the installation edge, and each bolt hole of the front guard edge is set as a washer, forming a lace structure as a whole; the rear guard edge 7 corresponding to the front guard edge is hollowed at each corresponding washer structure for passing bolts. The digging washer 6 is a rotating structure, forming a cover structure as a whole. The lace washer 5 and the digging washer 6 are connected by welding at the washer position to form a bolt guard ring 2. The lace washer 5 wraps the windward side mounting edge 8 and the leeward side mounting edge 9 inside it to avoid the impact of high-temperature and high-pressure airflow on the windward side mounting edge 8 and the leeward side mounting edge 9. The digging washer 6 wraps the nut of the mounting edge bolt 10 inside it, so that the high-temperature and high-pressure airflow flowing along the outer wall of the nut support plate 4 continues to flow along the outside of the lace washer 5 and the digging washer 6.

[0035] The assembly method of the retaining ring is as follows:

[0036] First, assemble the nut guard 1 to the mounting edge 8 on the windward side of the inner casing, ensuring that the nut support plate 4 corresponds to the bolt hole, and then assemble the bolt guard 2 to the mounting edge 9 on the leeward side, ensuring that the cut edge corresponds to the bolt hole and the annular tube structure of the lace washer 5 covers the mounting edge, and finally install the mounting edge bolt 10, the bolt passes through the cut edge and washer of the bolt guard 2, and is screwed into the nut support plate 4 to complete the assembly work.

[0037] After the guard ring is installed, during the operation of the engine, the high-temperature and high-pressure airflow is directly blocked by the nut guard ring 1, blocking the aerodynamic thermal shock to the bolt and nut connection. Then, after the airflow flows along the outer edge of the nut guard ring 1 and flows through the assembly position of the mounting edge, the annular tube structure of the nut guard ring 1 and the bolt guard ring 2 forms an integral protective cover to isolate the high-temperature airflow from the convection heat exchange of the mounting edge, thereby reducing the temperature difference of the matching mounting edge and balancing the deformation consistency of the matching mounting edge of the inner casing. Finally, after the airflow flows out of the guard ring, vortex reflux will be formed, but the rotating structure of the rear retaining edge 7 of the bolt guard ring 2 will form a protection mechanism. Although the digging edge used to pass the bolt may cause a small amount of heat flow reflux, it is not enough to affect this position because the digging edge area accounts for a small proportion and the gas heat reflux flow is small.

Claims

1. A method for balancing the deformation of an inner casing and protecting bolts, characterized in that: A guard ring is installed on the mounting side bolts at the matching positions of the front and rear sections of the inner casing to change the direction of high-temperature and high-airflow and protect the mounting edge and mounting side bolts and nuts at the matching positions of the front and rear sections of the inner casing.

2. A method for balancing inner casing deformation and protecting bolts according to claim 1, characterized in that: The retaining ring is divided into a nut retaining ring (1) and a bolt retaining ring (2), both of which are in an annular structure as a whole. The bolt retaining ring (2) is installed at the nut position of the mounting side bolt, and the nut retaining ring (1) is installed at the nut position.

3. A method for balancing inner casing deformation and protecting bolts according to claim 2, characterized in that: The nut retainer (1) comprises a front retainer (3) and a nut support plate (4), and wraps the nut of the mounting side bolt (10) inside the front retainer; the cross-sectional structure of the front retainer (3) is a "concave" type, and a hole is opened on the front retainer (3) and the nut support plate (4) is assembled.

4. A method for balancing inner casing deformation and protecting bolts according to claim 3, characterized in that: The nut support plate (4) is fixed to the front baffle retainer (3) by means of expansion.

5. A method for balancing inner casing deformation and protecting bolts according to claim 4, characterized in that: During the assembly process of the nut support plate (4), the angle of the outer edge clamping part needs to be adjusted to prevent interference caused by assembly at the installation edge position of the inner casing.

6. A method for balancing inner casing deformation and protecting bolts according to claim 1, characterized in that: The bolt retainer (2) comprises a lace washer (5) and a cut-out washer (6) which are arranged back to back and are fixed by welding.

7. A method for balancing inner casing deformation and protecting bolts according to claim 6, characterized in that: The lace washer (5) wraps the windward side mounting edge (8) and the leeward side mounting edge (9) inside thereof, and has an "L"-shaped cross section, forming a lace structure as a whole. Each bolt hole on the mounting edge of the lace washer (5) is provided with a washer, and the middle portion is a ring tube structure.

8. A method for balancing inner casing deformation and protecting bolts according to claim 7, characterized in that: The edge-cutting washer (6) wraps the nut of the mounting edge bolt (10) inside it, and has a "concave" cross-section, wherein the front edge is the mounting edge, and each bolt hole of the front edge is set as a washer, forming a lace structure as a whole; the rear edge (7) corresponding to the front edge is processed with an edge cut at each corresponding washer structure.

9. A method for balancing inner casing deformation and protecting bolts according to claim 1, characterized in that: The assembly method of the retaining ring is as follows: First, assemble the nut retainer (1) onto the mounting edge (8) on the windward side of the inner casing, then assemble the bolt retainer (2) onto the mounting edge (9) on the leeward side, and finally install the mounting edge bolts (10) and screw them into the nut retainer (1) to complete the assembly work.

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