A tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disc

Abstract

The present invention belongs to the technical field of aircraft engine repair, and specifically relates to a tool for repairing cracks at the bottom of a low-pressure turbine disc tenon groove. The tool comprises a shank, a first coarse tooth area, a second coarse tooth area, and a fine tooth area. The present invention can repair the bottom of the low-pressure turbine disc tenon groove by broaching, and after the repair, the stress distribution at the tool joint is uniform, so the tool can be installed and used again.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine repair, and in particular relates to a tool for repairing cracks at the bottom of a tenon groove of a low-pressure turbine disc. Background Art

[0002] During operation, aircraft engine low-pressure turbine disks are subjected to both circumferential forces from the blades attached to the disks and their own centrifugal forces. While the loads they withstand meet design requirements, fatigue cracks can develop at the bottom of the grooves after prolonged operation. Due to the lack of effective repair methods, disks with cracks at the bottom of the grooves are forced to be replaced. Given the high cost of low-pressure turbine disks, forgoing repairs would be a significant waste of resources. Currently, existing tools and methods for repairing cracks in these parts are unable to fully repair the cracks and meet operational requirements. Summary of the Invention

[0003] In view of this, in order to solve the problem that cracks at the bottom of the tenon groove of the low-pressure turbine disk of an aircraft engine cannot be repaired and to extend the service life of the low-pressure turbine disk, the present invention provides a tool for repairing cracks at the bottom of the tenon groove of the low-pressure turbine disk. The tool can repair the bottom of the tenon groove of the low-pressure turbine disk by broaching, and the stress distribution at the joint of the tool after repair is uniform, so the tool can be installed and used again.

[0004] In order to achieve the above technical objectives, the specific technical solutions adopted by the present invention are:

[0005] A tool for repairing cracks at the bottom of a low-pressure turbine disc tongue and groove, comprising:

[0006] A handle, configured as a working end, capable of pulling in the mortise and tenon groove;

[0007] a first coarse tooth zone, fixed to the working end, comprising a plurality of first coarse teeth arranged in a straight line, wherein the first coarse cutting teeth are used to grind cracks at the bottom of the mortise;

[0008] A second coarse tooth area is fixed to the working end and is disposed adjacent to the first coarse tooth area, and includes a plurality of second coarse teeth arranged in a straight line, wherein the second coarse teeth are used to grind the secondary stress area formed at the bottom of the mortise and tenon groove after being ground by the first coarse teeth;

[0009] The fine tooth area is fixed to the working end and is arranged at an end of the second coarse tooth area away from the first coarse tooth area. It includes a plurality of fine cutting teeth. The fine cutting teeth are used to grind the entire bottom of the mortise and tenon groove.

[0010] Furthermore, the bottom cross-section of the mortise and tenon groove is an axisymmetric special shape, and the outer shape, after being evenly divided by the axis of symmetry, comprises an expansion section and a convergence section, the expansion section is open at one end away from the convergence section, and the convergence section is closed at one end away from the expansion section;

[0011] The first rough cutting teeth are used to grind part of the convergent section, the second rough cutting teeth are used to grind all of the expansion sections and part of the convergent section, and the fine cutting teeth are used to grind all of the expansion sections and all of the convergent sections.

[0012] Furthermore, the grinding areas of the first rough cutting teeth and the second rough cutting teeth partially overlap.

[0013] Furthermore, the first rough cutting tooth is provided with a first grinding portion, the cross-sectional shape of the first grinding portion is an axisymmetric arc, and the cross-sectional shape of the first grinding portion is consistent with the shape of the closed end of the convergent section; the first rough cutting tooth is configured so that during the cutting process, no part except the first grinding portion can contact the bottom of the mortise.

[0014] Furthermore, the second rough cutting tooth is provided with two axially symmetrical second grinding parts; in the cross section of the second rough cutting tooth, the two second grinding parts are connected based on an avoidance section that does not participate in grinding; the cross section of the two second grinding parts is consistent with the outer shape of all the expansion sections and part of the convergence sections; the second rough cutting tooth is configured so that during the cutting process, no part except the second grinding part can contact the bottom of the mortise and tenon.

[0015] Furthermore, the fine-cutting teeth are provided with a third grinding portion, and the cross-sectional shape of the third grinding portion is consistent with the cross-sectional shape of the bottom of the mortise and tenon.

[0016] Furthermore, the first coarse tooth area is provided with 8-12 first coarse cutting teeth.

[0017] Furthermore, the second coarse tooth area is provided with 8-12 second coarse cutting teeth.

[0018] Furthermore, the fine tooth area is provided with 9-13 fine cutting teeth.

[0019] Furthermore, an avoidance gap is provided between the first coarse tooth area and the second coarse tooth area.

[0020] By adopting the above technical solution, the present invention can also bring the following beneficial effects:

[0021] The tool structure and use method of the present invention are simple, and the repair effect on the cracks at the bottom of the tenon groove of the low-pressure turbine disk is significant, thereby prolonging the service life of the low-pressure turbine disk after repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is the structural diagram of the tongue and groove of the low-pressure turbine disc;

[0024] Figure 2 Schematic diagram of the tooth profile of the first rough cutting tooth;

[0025] Figure 3 Schematic diagram of the tooth profile of the second rough cutting tooth;

[0026] Figure 4 Schematic diagram of the tooth profile of precision cutting teeth;

[0027] Figure 5 A schematic diagram of the overall structure of a tool for repairing cracks at the bottom of the tenon groove of a low-pressure turbine disc;

[0028] Among them: 1. Shank; 2. First coarse tooth area; 3. Second coarse tooth area; 4. Fine tooth area. DETAILED DESCRIPTION

[0029] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0030] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0031] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0032] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0033] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0034] In one embodiment of the present invention, a tool for repairing cracks at the bottom of a low-pressure turbine disc groove is provided. Figure 5 As shown, including:

[0035] The handle 1 is configured as a working end to enable pulling in the mortise and tenon groove;

[0036] A first coarse tooth area 2, fixed at the working end, includes a plurality of first coarse teeth arranged in a straight line, the first coarse cutting teeth being used for grinding cracks at the bottom of the mortise and tenon;

[0037] The second coarse tooth area 3 is fixed at the working end and is arranged adjacent to the first coarse tooth area 2, and includes a plurality of second coarse teeth arranged in a straight line. The second coarse teeth are used to grind the secondary stress area formed at the bottom of the mortise and tenon groove after being ground by the first coarse tooth area 2;

[0038] The fine tooth area 4 is fixed at the working end and is arranged at the end of the second coarse tooth area 3 away from the first coarse tooth area 2. It includes a plurality of fine cutting teeth, which are used to grind the entire bottom of the tenon groove.

[0039] In this embodiment, if Figure 1 As shown, the cross section of the bottom of the mortise and tenon groove is an axisymmetric special shape. The outer shape is evenly divided by the symmetry axis and includes an expansion section and a convergence section. The expansion section is open at one end away from the convergence section, and the convergence section is closed at one end away from the expansion section.

[0040] The first rough cutting teeth are used for grinding part of the convergent section, the second rough cutting teeth are used for grinding all the expansion sections and part of the convergent section, and the fine cutting teeth are used for grinding all the expansion sections and all the convergent sections.

[0041] In this embodiment, the first roughing teeth partially overlap with the grinding area of ​​the second roughing tooth area 3 .

[0042] In this embodiment, if Figure 2 As shown, the first rough cutting tooth is provided with a first grinding portion, the cross-sectional shape of the first grinding portion is an axisymmetric arc, and the cross-sectional shape of the first grinding portion is consistent with the shape of the closed end of the convergent section; the first rough cutting tooth is arranged so that during the cutting process, no part except the first grinding portion can contact the bottom of the mortise and tenon.

[0043] In this embodiment, if Figure 3 As shown, the second rough cutting tooth is provided with two axially symmetrical second grinding parts; in the cross section of the second rough cutting tooth, the two second grinding parts are connected based on an avoidance section that does not participate in grinding; the cross section of the two second grinding parts is consistent with the outer shape of all expansion sections and part of the convergence section; the second rough cutting tooth is set as follows: during the cutting process, except for the second grinding part, no part can contact the bottom of the mortise.

[0044] In this embodiment, if Figure 4 As shown, the finishing tooth is provided with a third grinding portion, and the cross-sectional shape of the third grinding portion is consistent with the cross-sectional shape of the bottom of the mortise.

[0045] In this embodiment, the first roughing tooth zone 2 is provided with 8-12 first roughing teeth.

[0046] In this embodiment, the second rough cutting teeth zone 3 is provided with 8-12 second rough cutting teeth.

[0047] In this embodiment, the fine tooth zone 4 is provided with 9-13 fine cutting teeth.

[0048] In this embodiment, an avoidance gap is provided between the first coarse-toothed area 2 and the second coarse-toothed area 3 .

[0049] like Figure 1 As shown, the dotted line is the repair position of the bottom of the tenon groove of the low-pressure turbine disc. This embodiment uses the original arc-shaped structure of the bottom of the tenon groove as the basis for the design of the broaching cutting teeth. By optimizing the structure of the broaching cutting teeth, stress concentration at the bottom of the tenon groove of the low-pressure turbine disc after repair is avoided, thereby ensuring the strength requirements of the tenon groove of the low-pressure turbine disc. During repair, after the first two sections of rough cutting teeth are cut and formed, the fine cutting teeth are finely processed. At the same time, the low-pressure turbine disc to be repaired needs to be clamped on the workbench, and the last fine cutting tooth is inserted into the bottom of the tenon groove. The parts are pressed and broached to ensure the symmetry and surface requirements of the bottom of the tenon groove. The clamping fixture used for repairing the tool of this embodiment is an ordinary broaching fixture, and no special fixture is required.

[0050] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A tool for repairing cracks at the bottom of a low-pressure turbine disc groove, characterized in that: include: A handle, configured as a working end, capable of pulling in the mortise and tenon groove; a first coarse tooth zone, fixed to the working end, comprising a plurality of first coarse cutting teeth arranged in a straight line, wherein the first coarse cutting teeth are used to grind cracks at the bottom of the mortise; a second roughing tooth section, fixed to the working end and disposed adjacent to the first roughing tooth section, comprising a plurality of second roughing teeth arranged in a straight line, the second roughing teeth being used to grind a secondary stress zone formed at the bottom of the mortise and tenon groove after being ground by the first roughing teeth; a fine tooth zone, fixed to the working end, disposed at an end of the second coarse tooth zone away from the first coarse tooth zone, comprising a plurality of fine cutting teeth, the fine cutting teeth being used to grind the entire bottom of the mortise and tenon groove; The cross-section of the bottom of the mortise and tenon is an axisymmetric special shape, and the outer shape includes an expansion section and a convergence section after being evenly divided by the axis of symmetry. The expansion section is open at one end away from the convergence section, and is closed at one end away from the expansion section; the first rough cutting tooth is used to grind part of the convergence section, the second rough cutting tooth is used to grind all of the expansion section and part of the convergence section, and the fine cutting tooth is used to grind all of the expansion section and all of the convergence section, wherein the first rough cutting tooth is provided with a first grinding portion, the cross-sectional shape of the first grinding portion is an axisymmetric arc, and the cross-sectional shape of the first grinding portion is consistent with the shape of the closed end of the convergence section; the first rough cutting tooth is configured such that, during the cutting process, no portion other than the first grinding portion can contact the bottom of the mortise and tenon; The second rough cutting tooth is provided with two axially symmetrical second grinding parts; in the cross section of the second rough cutting tooth, the two second grinding parts are connected based on an avoidance section that does not participate in grinding; the cross section of the two second grinding parts is consistent with the outer shape of all the expansion sections and part of the convergence sections; the second rough cutting tooth is configured so that during the cutting process, no part except the second grinding part can contact the bottom of the mortise and tenon.

2. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disc according to claim 1, characterized in that: The grinding areas of the first roughing teeth and the second roughing teeth partially overlap.

3. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disc according to claim 2, characterized in that: The finishing tooth is provided with a third grinding portion, and the cross-sectional shape of the third grinding portion is consistent with the cross-sectional shape of the bottom of the mortise and tenon.

4. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disc according to claim 3, characterized in that: The first coarse tooth area is provided with 8-12 first coarse cutting teeth.

5. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disc according to claim 4, characterized in that: The second coarse tooth area is provided with 8-12 second coarse cutting teeth.

6. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disk according to claim 5, characterized in that: The fine tooth area is provided with 9-13 fine cutting teeth.

7. The tool for repairing cracks at the bottom of the tongue and groove of a low-pressure turbine disk according to claim 6, characterized in that: An avoidance gap is provided between the first coarse tooth area and the second coarse tooth area.

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