Method for repairing inner hole of engine compressor casing

Abstract

The invention discloses a method for repairing an inner hole of an engine compressor casing, which comprises the following steps of: performing surfacing on reinforcing rings, namely surfacing a plurality of stress point positions for bearing a rectifier or a working ring in the circumferential direction of each reinforcing ring, the stress point positions are distributed near the joint surface gasket and at the radial position perpendicular to the joint surface of the upper half casing and the lower half casing. According to the method, the stress point positions are arranged on the reinforcing ring in a local surfacing mode to achieve repairing of the inner hole, the stress point positions are selected at the positions with relatively small deformation size out-of-tolerance of the cartridge receiver, the assembling and using stability of an object piece can be high, and the positioning and assembling requirements of the object piece are fully met.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engine maintenance, and in particular to a method for repairing an inner hole of an engine compressor casing. Background Art

[0002] The compressor casing of an aircraft engine is a half casing, and its structure is as shown in the attached manual. Figure 1 and Figure 2 As shown, the upper casing, the lower casing, and the joint surface gasket are assembled into a whole by bolts, and the inner hole of the casing is equipped with multiple rectifiers and working rings arranged alternately. The rectifier is assembled to the inner hole of the casing by bolts, and the working ring is axially limited by the rectifier. The working ring is a rotatable movable part, and its circumferential direction is limited by the joint surface gasket. Specifically, a block is provided on the working ring, and the block rotates with the working ring until it contacts the joint surface gasket and is blocked. The inner hole of the compressor casing is a straight hole, and the inner hole edge has no smooth transition zone such as chamfers and fillets.

[0003] The above-mentioned aircraft engine needs to be returned to the factory for inspection and overhaul after one service life. During the inspection of its compressor casing, it was found that the inner hole size was out of tolerance. In conventional operations, the following methods are usually used to repair the inner hole size out of tolerance:

[0004] 1) The inner hole size is reduced by grinding and thinning the thickness of the mating surface gasket, but this operation can only reduce the size of the inner hole in the direction perpendicular to the gasket by 1:1, and the reduction amount of the rest of the inner hole in the direction of the gasket is gradually reduced. That is, this method does not have a good effect on the change of the inner hole size value of the casing, and will eventually affect the assembly of the rectifier in the inner hole. Moreover, the maximum allowable removal amount of the mating surface gasket thickness grinding is 0.5mm, which is difficult to apply to the overall tolerance of the inner hole and the multiple repairs of the compressor casing. It is impossible to guarantee the size of the casing and the assembly requirements of the two types of objects, the rectifier and the working ring, which will eventually cause the casing to be scrapped and replaced, resulting in high engine repair costs.

[0005] 2) Through welding repair, the welding operation is not limited by the bonding force, and welding repair can be performed multiple times to meet the needs of multiple repairs of parts. However, the deformation amounts at different positions of the inner hole of the casing are different, and the requirements for weld height are different. During actual welding operations, it is very easy to cause excessive welding in a large local area, thereby increasing the difficulty of controlling thermal deformation.

[0006] 3) Repair by spraying metal material on the inner hole of the receiver, such as spraying, but the edge of the inner hole of the receiver has no chamfers or fillets to serve as a smooth transition zone, which has a great impact on the bonding strength of the spray layer and is prone to coating peeling, resulting in unqualified inner hole repair.

[0007] Moreover, when the inner hole after spraying is returned to the factory for repair after use, the original coating needs to be removed and re-sprayed. Due to the deformation of the parts, after removing the old coating, the size of the inner hole will be much larger than the previous repair, which greatly increases the coating thickness requirement. The casing will be difficult to repair again and cannot meet the needs of multiple engine repairs.

[0008] The patent with the publication number CN115041914A discloses a method for repairing the inner hole of a casing, including a process gasket for setting between the longitudinal mounting edge of the first flap casing and the longitudinal mounting edge of the second flap casing, and the repair method includes: combining the half-machine brake, setting the process gasket between the longitudinal mounting edge of the first flap casing and the longitudinal mounting edge of the second flap casing, and protruding the process gasket toward one end of the inner wall of the casing; spraying; turning the coating, and the coating is continuously disconnected at the position of the process gasket; disassembling. This patent uses a process gasket to replace the traditional gasket in the process of inner hole repair, changes the relative position of the gasket and the inner hole of the casing, and the side of the process gasket facing the inner hole wall of the casing is protruded relative to the inner hole wall of the casing, and the height dimension of the protruding setting is adapted to the thickness dimension requirement of the coating formed in the subsequent spraying step, so that the coating at the process gasket position is continuously disconnected from the casing part coating during the turning process, thereby changing the way of removing the coating at the gasket position, and solving the problem that the edge of the inner hole coating is easy to peel off and the gasket is easy to be damaged when the two flaps of the casing are disassembled after spraying.

[0009] Although the above patent is also aimed at repairing the inner hole of the receiver, a careful reading of its description of the receiver structure and the relevant features shown in the drawings shows that the receiver structure recorded in the patent is different from that of the present invention. It is not a straight hole design like the receiver structure of the present invention. The inner hole of the receiver of the patent can meet the requirements of stable adhesion of the coating, and its designed coating repair method is adapted to its receiver structure.

[0010] However, the inner hole of the aircraft engine casing of the present invention is a straight hole, and the edge of the inner hole has no smooth transition areas such as chamfers and fillets, and the inner hole has a large diameter. The casing as a whole is easy to deform, and the deformation amount of the size at different positions of the inner hole is different. Conventional inner hole additive repair methods are not applicable. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide a method for repairing the inner hole of an engine compressor casing, which can meet the requirements of stable assembly of the object part and the casing and has almost no deformation, in view of the defects of the prior art.

[0012] The purpose of the present invention is achieved through the following technical solutions:

[0013] A method for repairing the inner hole of an engine compressor casing is to perform a surfacing operation on a reinforcement ring. The surfacing operation includes surfacing a plurality of stress points for supporting a rectifier or a working ring on the circumference of each reinforcement ring. The stress points are distributed near a joint surface gasket and at radial positions perpendicular to the joint surfaces of an upper casing and a lower casing.

[0014] The object to be repaired by the repair method of the present invention is the inner hole of the half casing composed of the upper casing, the lower casing and the joint surface gasket. The inner wall of the casing is integrally provided with a plurality of reinforcement rings distributed at intervals along the axial direction. The reinforcement rings are used to install the rectifier and the working ring. The plurality of rectifiers and working rings are alternately arranged in sequence in the inner hole of the casing. The casing is provided with a plurality of connection holes for fixing the rectifier in the circumferential direction corresponding to the position of each rectifier. The working ring is axially limited by the rectifier, and the working ring is a rotatable movable part.

[0015] Furthermore, the multiple stress-bearing points in the circumferential direction of each reinforcement ring include at least points corresponding one-to-one to the position distribution of the connection holes.

[0016] Furthermore, the number of circumferential force-bearing points of each reinforcement ring is equal to the number of connecting holes.

[0017] Furthermore, the surfacing operation also includes surfacing a plurality of supporting points for auxiliary supporting the rectifier or the working ring on the circumference of each reinforcement ring.

[0018] Furthermore, a supporting point is arranged between every two adjacent stress-bearing points, and the supporting point equally divides the reinforcing ring segment between the two stress-bearing points.

[0019] Furthermore, the surfacing operation is segment-by-segment surfacing, and segment-by-segment surfacing is surfacing multiple segments in sequence along the axial direction of the inner hole of the casing.

[0020] Furthermore, the dimension of each section of surfacing along the axial direction of the inner hole of the casing is 1 to 3 mm.

[0021] Furthermore, the dimension of each section of surfacing welding on the radial cross section of the casing perpendicular to the radial direction is 10 to 15 mm.

[0022] Furthermore, when the upper half of the casing and the lower half of the casing are assembled in half, both ends of the casing are first pre-tightened diagonally.

[0023] Furthermore, the plurality of stress points are built-up welded in the following order: two axially symmetrical stress points are selected near the joint surface gasket of the casing as a first group of stress points and cross-welded first, then welded at the radial position, and then another two axially symmetrical stress points are selected near the joint surface gasket of the casing as a second group of stress points and cross-welded; the first group of stress points and the second group of stress points are symmetrically distributed relative to the joint surface gasket.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This repair method sets stress points on the reinforcement ring by local surfacing to achieve the repair of the inner hole. The stress points are selected at positions where the deformation size deviation of the casing is relatively small, which can make the assembly and use of the rectifier and the working ring highly stable and fully meet the positioning and assembly requirements of the target parts.

[0026] The local surfacing welding method has a smaller welding heat input and less deformation of the casing. The stress points combined with the supporting points evenly support the target part. It can meet the needs of different tolerance states of the casing inner hole, the need to ensure the assembly of the target part when repairing the casing inner hole, and the need to perform multiple repairs on the casing inner hole, and maximize the guarantee that the target part and the casing are assembled without deformation.

[0027] The use of this repair method can effectively reduce the repair cost and shorten the repair cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of the casing to be repaired in Example 1 of the present invention;

[0029] Figure 2 It is a top cross-sectional view of the casing to be repaired in Example 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of the assembly sequence of the positioning bolts of the half casing of the repair object in Example 1 of the present invention;

[0031] Figure 4 A schematic diagram of the position of the surfacing welding on the inner hole reinforcement ring of the casing according to Example 1 of the present invention;

[0032] Figure 5 It is a schematic diagram of the welding sequence of each welding point on the inner hole reinforcement ring of the casing described in Example 1 of the present invention.

[0033] Figure 6 This is a schematic diagram of the segment-by-segment surfacing described in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] In order to clearly illustrate the technical features of the present solution, the present technical solution is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0036] In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0037] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the present application, unless otherwise clearly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0039] Example 1

[0040] like Figure 1 and Figure 2 The compressor casing of the aircraft engine shown in the figure is a half casing composed of an upper casing 1 and a lower casing 2 assembled by bolts. A joint surface gasket 3 is provided at the joint of the upper casing 1 and the lower casing 2. A plurality of reinforcement rings 4 distributed at intervals are integrally provided on the inner wall of the casing along the axial direction. The reinforcement ring 4 is used to install a rectifier 5 and a working ring 6 ( Figure 1 Only a small part of the rectifier is shown, and the rest of the circumferential part is omitted). Multiple rectifiers 5 and working rings 6 are arranged alternately in the inner hole of the casing, and the casing is provided with multiple connecting holes for fixing the rectifiers in the circumferential direction corresponding to the position of each rectifier 5, and connecting bolts 7 are installed in the connecting holes. The working ring 6 is a rotatable movable part, and its axial direction is limited by the rectifier 5.

[0041] This embodiment fully considers the different deformation amounts at different positions of the casing, the need to ensure the assembly requirements of engine components, and the need to meet the problem of multiple engine repairs, and adopts a repair method of surfacing welding on the inner hole of the compressor casing, more specifically, a local surfacing welding and then machining method to control the deformation of the casing and prevent the deformation of the rectifier and working ring after assembly.

[0042] The following is a step-by-step description of the repair method:

[0043] 1) Assemble the two halves of the casing: Use bolts to assemble the upper casing 1, the lower casing 2 and the joint surface gasket 3, so that the casing is in an integral constraint, and the deformation of the mounting edges at both ends of the casing and the longitudinal mounting edges of the halves is controlled, so as to prepare for the subsequent control of the deformation of the surfacing welding.

[0044] The bolt assembly sequence for assembling and positioning the two halves of the casing is as follows: Figure 3 As shown, first pre-tighten the bolts at both ends of the receiver diagonally, then pre-tighten the bolts in the middle section of the receiver symmetrically, and finally pre-tighten the other bolts, and then tighten all the bolts in the pre-tightening order. Figure 3 Take the ten bolt connections as an example, and tighten them in sequence from a to j.

[0045] 2) Determine the surfacing locations: The surfacing operation is performed on the reinforcement ring 4. First, multiple stress points 41 for supporting the rectifier 5 or the working ring 6 are circumferentially surfacing-welded on each reinforcement ring 4. The stress points 41 are required to be distributed near the joint surface gasket 3 and at radial positions perpendicular to the joint surfaces of the upper casing 1 and the lower casing 2. The casing deformation at these locations is in good condition, and the casing deformation size tolerance is relatively small, which can make the assembly and use stability of the rectifier 5 and the working ring 6 higher.

[0046] To further enhance the assembly stability of the object, the multiple force points 41 in the circumferential direction of each reinforcement ring 4 at least include points corresponding to the position distribution of the connection holes on the casing for fixing the rectifier 5. If the process operation needs to be simplified, the number of force points 41 can be exactly equal to the number of connection holes.

[0047] In this embodiment, Figure 4 As shown, three stress points 41 are arranged on each half-casing, and the stress points 41 on the upper half-casing 1 and the lower half-casing 2 are arranged in exactly the same manner.

[0048] In addition, the surfacing operation of this embodiment also includes surfacing a plurality of support points 42 for auxiliary support of the rectifier 5 or the working ring 6 on each reinforcement ring 4 in the circumferential direction. Specifically, a support point 42 is set between every two adjacent stress points 41, and the position of the support point 42 is usually to evenly divide the reinforcement ring segment between the two stress points 41. Because the working ring 6 is a thin-walled annular part, it is easy to deform with the inner hole of the random casing due to vibration factors during assembly and engine use. With only the support of the stress point 41, the working ring 6 is very likely to be locally deformed, which in turn affects the clearance requirement between it and the blades of the rectifier 5, and eventually causes scraping, and even causes the problem that the working ring cannot rotate circumferentially. The jamming of the working ring will cause engine failure. The setting of the support point 42 can help prevent deformation of the casing and the working ring during assembly or use, and provide more uniform and reliable support for the working ring 6 and the rectifier 5.

[0049] In actual operation, the processing time required for surfacing welding a stress point 41 or support point 42 is about 15 minutes. In principle, the more stress points 41 and support points 42 are set, the more beneficial it is to prevent the assembly deformation of the casing, rectifier 5, and working ring 6. However, the more stress points 41 and support points 42 there are, the longer the inner hole of the casing will take to repair. In order to balance the duration of the surfacing operation and the assembly stability effect of the target part, three stress points 41 and two support points 42 are set on each half casing to meet the repair requirements. It has been verified that the above number of stress points 41 and support points 42 can effectively avoid scraping and jamming between the casing and the target part, and at the same time avoid the occurrence of other related engine failures.

[0050] 3) Welding: Figure 5 As shown, six stress points 41 are marked as k~p on the casing, among which stress points 41k, l, o, p are distributed near the joint surface gasket 3, the two stress points k and l 41, and the two stress points o and p 41 are symmetrical about the central axis of the casing, and the two stress points k and p 41, and the two stress points o and l 41 are symmetrical about the joint surface gasket 3; the two stress points m and n 41 are distributed at radial positions perpendicular to the joint surfaces of the upper casing 1 and the lower casing 2, among which the m, k, o stress points 41 are located on the same half-casing.

[0051] The four supporting points 42 are marked as q to t on the casing, the two supporting points q and r 42 and the two supporting points s and t 42 are respectively symmetrical about the central axis of the casing, and the two supporting points q and t 42 and the two supporting points s and r 42 are respectively symmetrical about the joint surface gasket 3.

[0052] The stress points are welded in the following order: the two stress points k and l are cross-welded as the first stress point group, then the stress points m and n are welded in turn, and then the two stress points o and p are cross-welded as the second stress point group.

[0053] The support points are welded in the following order: the two support points 42 of q and r are welded crosswise first, and then the two support points 42 of s and t are welded crosswise.

[0054] The cladding at each point is performed in sections in order to shorten the single welding time, control the heat input, and help prevent deformation. Figure 6 As shown, multiple sections are sequentially and parallelly built-up along the axial direction of the inner hole of the casing. In this embodiment, two sections are built-up, and the height of each section of the built-up 8 is not less than 0.6mm (the height refers to the thickness of the built-up in the direction perpendicular to the wall surface of the inner hole of the casing), the dimension of each section of the built-up 8 perpendicular to the radial direction on the radial section of the casing (i.e., the weld width) is 10-15mm, and the dimension of each section of the built-up 8 along the axial direction of the inner hole of the casing is 1-3mm. In principle, the above three dimensions of each section of the built-up at each point take the same value.

[0055] The section-by-section surfacing can further realize the uniform support of the inner hole of the casing for the rectifier 5 and the working ring 6, and ensure that there is no deformation in the subsequent assembly to the maximum extent, and fully guarantee the assembly requirements of the object parts. Water cooling is required during the surfacing process. The casing is placed in cold water, and the welding part is exposed to the water surface and kept dry. Each welding section needs to be cooled before welding the next section.

[0056] 4) Processing: Turn the welded area to the required size of the inner hole of the casing (i.e. the required size of the reinforcing ring).

[0057] 5) Finishing: Grind the welding protrusion that exceeds the end face of the reinforcement ring until it is flush with the end face base to eliminate the interference problem of end face assembly.

[0058] It should be noted that the casing in this embodiment is a half casing, and in other embodiments, it can also be a multi-petal casing.

[0059] Example 2

[0060] The segment-by-segment surfacing in this embodiment is to sequentially surfacing 3 to 5 segments along the axial direction of the inner hole of the casing.

[0061] Comparative Example 1

[0062] This comparative example is to add material to the inner hole of the casing, that is, fill the coating in the relevant parts of the inner hole of the casing that are in contact with the outer periphery of the object. After testing, the coating peeled off seriously and could not really stably support and position the rectifier and the working ring, and the inner hole repair failed.

[0063] Obviously, the above embodiments are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for repairing the inner hole of an engine compressor casing, It is characterized in that A surfacing operation is performed on the reinforcement ring, and the surfacing operation includes surfacing a plurality of stress points for supporting the rectifier or the working ring on the circumference of each reinforcement ring, and the stress points are distributed near the joint surface gasket and at radial positions perpendicular to the joint surfaces of the upper and lower casing halves.

2. The method for repairing the inner hole of an engine compressor casing according to claim 1, It is characterized in that The multiple stress-bearing points around each reinforcement ring at least include points corresponding to the position distribution of the connection holes.

3. The method for repairing the inner hole of an engine compressor casing according to claim 2, It is characterized in that The number of circumferential force bearing points of each reinforcement ring is equal to the number of connecting holes.

4. The method for repairing the inner hole of an engine compressor casing according to claim 1, It is characterized in that The surfacing operation also includes surfacing a plurality of supporting points for auxiliary supporting the rectifier or the working ring on the circumference of each reinforcement ring.

5. The method for repairing the inner hole of an engine compressor casing according to claim 4, It is characterized in that A supporting point is arranged between every two adjacent stress-bearing points, and the supporting point equally divides the reinforcing ring segment between the two stress-bearing points.

6. The method for repairing the inner hole of an engine compressor casing according to claim 1, It is characterized in that The surfacing operation is segment-by-segment surfacing, and segment-by-segment surfacing is to sequentially surfacing multiple segments along the axial direction of the inner hole of the casing.

7. The method for repairing the inner hole of an engine compressor casing according to claim 6, It is characterized in that The axial dimension of each section of surfacing along the inner hole of the casing is 1 to 3 mm.

8. The method for repairing the inner hole of an engine compressor casing according to claim 6, It is characterized in that The dimension of each section of surfacing welding perpendicular to the radial direction on the radial cross section of the casing is 10 to 15 mm.

9. The method for repairing the inner hole of an engine compressor casing according to claim 1, It is characterized in that When assembling the upper and lower halves of the receiver, pre-tighten both ends of the receiver diagonally first.

10. The method for repairing the inner hole of an engine compressor casing according to claim 1, It is characterized in that The multiple stress points are built-up welded in the following order: two axially symmetrical stress points are selected near the joint surface gasket of the casing as the first group of stress points and are first cross-welded, then welded at the radial position, and then another two axially symmetrical stress points are selected near the joint surface gasket of the casing as the second group of stress points and are cross-welded; the first group of stress points and the second group of stress points are symmetrically distributed relative to the joint surface gasket.

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