A special cutting tool and machining method for removing welded joints in the confined space of an aircraft engine.

Abstract

This invention discloses a special cutting tool and machining method for removing welded stops within the confined space of an aero-engine. The special cutting tool includes a tool holder and a cutting plate. The head of the tool holder has a spindle interface for connection to a machine tool spindle. The cutting plate is generally flat, with a cutting edge at its end for removing the welded stop. The tool holder and cutting plate are connected by a connecting mechanism, and the connected tool holder and cutting plate are L-shaped. The machining method adopts a "separate, internally connected" design concept, cleverly solving the problem of the tool being unable to enter the ultra-narrow inlet deep cavity.

Description

Technical Field

[0001] This invention relates to a special tool and processing method for removing welded joints in the confined space of an aero-engine, belonging to the field of aero-engine processing technology. Background Technology

[0002] To reduce weight and improve performance, core components of modern aero engines (such as compressors) often employ integral bladed disk structures. In existing technologies, multi-stage integral bladed disks are typically connected using electron beam welding, and positioning and interference fit are achieved through the design of weld stops to ensure weld quality.

[0003] However, after welding, to ensure the stability of engine airflow, the weld stops used as process references must be removed. These weld stops are often located in extremely narrow, enclosed spaces formed between the blades of the two-stage bladed disks (e.g., inlet width ≤ 21mm, depth > 150mm). This structural characteristic makes it impossible for conventional cutting tools to enter, or even if they do, there is insufficient space for them to complete the cutting operation. During machining, the cutting tool is highly susceptible to collision with the precision blades on both sides, resulting in part scrap and posing a very high risk. Currently, there is a lack of mature and reliable solutions in China, and this machining challenge is considered a rare technical bottleneck in the industry.

[0004] Therefore, there is an urgent need to invent a new type of cutting tool and processing method to safely, efficiently and accurately complete the removal of welded stops in such confined spaces. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention provides a special tool and processing method for removing welded stops in the confined space of an aero-engine, which solves the problem that existing tools cannot enter confined spaces or cannot operate safely in such spaces, and achieves precise and interference-free processing of welded stops in deep cavities and narrow gaps.

[0006] This invention is achieved through the following technical solution: A special tool for removing welded stops in the confined space of an aircraft engine includes a tool holder and a tool plate. The head of the tool holder is provided with a spindle interface for connecting to a machine tool spindle. The tool plate is generally flat and has a cutting edge at its end for removing welded stops. The tool holder and the tool plate are connected by a connecting mechanism, and the connected tool holder and tool plate are generally L-shaped.

[0007] The specific structure of the connecting mechanism is as follows: the tail of the tool handle is designed as a circular boss, with the central protruding part serving as a positioning block and the peripheral recessed stepped part serving as a keyway. The positioning block has an axially arranged threaded hole B and a circumferentially arranged threaded hole A inside. Correspondingly, the tool plate connecting head is designed as a groove with a stepped hole, the stepped hole being coaxial with the threaded hole. The upper circular groove is used to fit the positioning block at the tail of the tool handle, and the lower through hole is used to fit the screw B. After the tail of the tool handle is connected to the tool plate connecting head, the screw B is passed upwards through the through hole and the circular groove of the tool plate and then locked into the threaded hole B of the positioning block, thus locking the tool handle and the tool plate. A key is fitted in the keyway, and the key is locked into the threaded hole A of the positioning block by a horizontally arranged screw A.

[0008] The blade is designed as a left-type blade and a right-type blade according to the position of the weld stop. The left-type blade is used to process the weld stop adjacent to the left side plate, and the right-type blade is used to process the weld stop adjacent to the right side plate.

[0009] The blades are designed accordingly, with the left-shaped blade plate and the right-shaped blade plate being designed as left-shaped blades and right-shaped blades. After the left-shaped blade is installed on the left-shaped blade plate, the position of its blade tip is 0.5mm higher than the blade plate body. After the right-shaped blade is installed on the right-shaped blade plate, the position of its blade tip is 1mm higher than the blade plate body.

[0010] A machining method for removing welded stops within the confined space of an aero-engine, employing the aforementioned special cutting tool, includes the following steps: S1. Select the left or right blade according to the position of the weld stop to be processed; S2. Insert the blade plate separately: Manually insert the selected blade plate into the narrow space where the welding stop to be processed is located through the inner hole of the blade plate. Specifically, the left blade plate is slowly tilted and inserted through the 130mm diameter inner hole of the right blade plate. Due to the limited space, the left blade plate cannot be inserted into the left welding stop position through the inner hole of the left blade plate, and vice versa. S3. Machine tool tool holder introduction: The tool holder, which is already installed on the machine tool spindle, is precisely moved to the entrance of a narrow space through program control; S4. Internal Connection: At the entrance of the confined space, assemble and connect the connecting head of the blade plate to the tail of the blade handle. By tightening screw B, firmly and precisely connect the blade handle to the blade plate that has been pre-placed in the confined space. S5. Perform cutting: The machine tool spindle drives the entire connected tool to cut and remove the weld stop to be processed according to the preset machining trajectory and parameters; S6. Separation and Removal: After machining is completed, the machine tool spindle stops rotating. The connection between the tool holder and the tool plate is released inside the space. First, the tool holder is removed, and then the tool plate that has completed the task is manually removed.

[0011] The beneficial effects of this invention are as follows: Compared with the prior art, the advantages of the present invention are as follows: ①Breaking through physical space limitations: Through the design concept of "separate and internally connected", the problem of the tool being unable to enter the ultra-narrow inlet deep cavity is cleverly solved; ②Safe and reliable, collision-proof: The blade plate is customized based on the precise position and tolerance deformation of the weld stop, which fundamentally avoids the risk of collision between the tool and the precision part plate during the processing, and protects the valuable integral bladed disk workpiece. ③ High rigidity and high precision: The unique connecting mechanism ensures that the connected tool holder and tool plate have sufficient rigidity and repeatability, thereby ensuring the processing quality of the weld stop. ④ High efficiency and economy: This method is more stable and performs better than imported cutting tools, reduces dependence on foreign technology, solves the "bottleneck" problem in this field in China, and has significant economic and social benefits. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the integral bladed disk assembly with welded stops to be processed according to the present invention (the position and size of the narrow space are marked, and the relative positional relationship, spatial size and travel range of the tool holder between the welded stops on the left and right sides and the flange are clearly shown). Figure 2 Detailed structural dimensions of the cutting tool used for machining the left-side weld stop are provided. Figure 1 ; Figure 3 Detailed structural dimensions of the cutting tool used for machining the left-side weld stop are provided. Figure 2 ; Figure 4 Detailed structural dimensions of the cutting tool used for machining the left-side weld stop are provided. Figure 3 ; Figure 5 A schematic diagram of the cooling channel design for the cutting tool used to machine the left-side weld stop; Figure 6 For details on the structural dimensions of the cutting tool used to machine the right-side weld stop, please refer to the following: Figure 1 ; Figure 7 For details on the structural dimensions of the cutting tool used to machine the right-side weld stop, please refer to the following: Figure 2 ; Figure 8 For details on the structural dimensions of the cutting tool used to machine the right-side weld stop, please refer to the following: Figure 3 ; Figure 9 This is a schematic diagram of the cooling channel design for the tool used to machine the right-side weld stop.

[0014] The attached diagram is labeled as follows: 1. Tool holder, 1-1. Positioning block, 1-2. Threaded hole B, 1-3. Spindle interface, 1-4. Threaded hole A, 2-1. Left-type tool plate, 2-2. Right-type tool plate, 3. Screw A, 4. Key, 5. Screw B, 6. Plug, 7. Blade, 8-1. Left side plate, 8-2. Right side plate, 9-1. Left side weld stop, 9-2. Right side weld stop, 10. Coolant inlet, 11. Coolant channel, 12. Coolant outlet. Detailed Implementation

[0015] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] This embodiment provides a special tool for removing welded stops in the confined space of an aero-engine, including a tool holder and a tool plate. The head of the tool holder is provided with a spindle interface 1-3 for connecting to a machine tool spindle. The tool plate is generally flat, and its end is provided with a cutting blade 7 for removing welded stops. The tool holder and the tool plate are connected by a connecting mechanism. The connected tool holder and the tool plate are generally L-shaped and have a coolant channel 11 inside. The coolant channel 11 is connected to the coolant inlet 10 and the coolant outlet 12 respectively.

[0018] Tool holder: Used to connect to the machine tool spindle (such as BT50 interface), and is the main body for power transmission.

[0019] Cutting plate: This is the core module that carries the cutting blade and performs cutting tasks within confined spaces. Depending on the specific location of the weld stop to be processed within the space, such as near the left side plate 8-1 or the right side plate 8-2, the dimensions of the cutting plate need to be customized and precisely designed, resulting in a left-type cutting plate 2-1 and a right-type cutting plate 2-2.

[0020] The left-type cutter 2-1 is used to process the left-side weld stop 9-1. The thickness of the left-type cutter 2-1 (e.g., 11mm) is determined by comprehensively considering the shortest distance between the left-side weld stop 9-1 and the two side plates (e.g., 1.59mm and 12.84mm) and the welding deformation tolerance, ensuring that the left-type cutter 2-1 never interferes with the side plates when moving within its stroke. The length of the left-type cutter 2-1 is determined by the depth of the narrow space (e.g., 152mm).

[0021] The right-side cutting tool 2-2 is used to process the right-side welded stop 9-2. Since the right-side welded stop 9-2 is very close to the middle plate (e.g., 0.05mm), the thickness of the right-side cutting tool 2-2 (e.g., 12mm) needs to be designed more carefully. In this embodiment, an innovative "stepped" blade mounting structure is adopted, that is, the installed blade is higher than the blade body by a certain distance (e.g., 1mm), thereby creating a larger effective machining stroke for the blade tip while ensuring the structural strength of the blade.

[0022] Connection mechanism: Used to achieve quick and high-precision connection and separation of the tool holder and the tool plate in confined spaces. Specifically, it can be tightened from below by a screw, supplemented by a locating key and keyway (e.g., 11mm wide) for circumferential and radial positioning, ensuring extremely high repeatability and connection rigidity after the tool holder and tool bar are connected. The specific structure is as follows: The tail of the tool handle is designed as a circular boss, with the central protruding part serving as a positioning block 1-1 and the recessed stepped part on the periphery serving as a keyway. Inside the positioning block 1-1, there is an axially arranged threaded hole B1-2 and a transversely arranged threaded hole A1-4. Correspondingly, the blade plate connecting head is designed as a groove with a stepped hole. The stepped hole in the groove is coaxial with the threaded hole. The circular groove on the upper side is used to fit the positioning block 1-1 at the tail of the tool handle, and the through hole on the lower side is used to fit the screw B5. After the tail of the tool handle is connected to the blade plate connecting head, the screw B5 is passed upward through the through hole and the circular groove of the blade plate and then locked into the threaded hole B1-2 of the positioning block 1-1 to lock the tool handle and the blade plate. A key 4 is fitted in the keyway, and the key 4 is locked into the threaded hole A1-4 of the positioning block 1-1 by a transversely arranged screw A3.

[0023] Using the aforementioned specialized cutting tool, this embodiment provides a machining method for removing welded stops within the confined space of an aero-engine, comprising the following steps: S1. Select either the left-type blade 2-1 or the right-type blade 2-2 according to the position of the weld stop to be processed; S2 Insert the blade separately: Manually insert the selected blade into the narrow space where the welding stop to be processed is located through the inner hole of the blade plate; Specifically, the left blade is slowly tilted and inserted through the 130mm diameter inner hole of the right blade plate. Due to the limited space, the left blade cannot be inserted into the left welding stop position through the inner hole of the left blade plate, and the same applies to the right blade. S3. Machine tool tool holder introduction: The tool holder, which is already installed on the machine tool spindle, is precisely moved to the entrance of a narrow space through program control; S4. Internal connection: At the entrance of the narrow space, assemble and connect the connecting head of the blade plate to the tail of the blade handle. By locking screw B5, firmly and precisely connect the blade handle to the blade plate that has been placed in the narrow space. S5. Perform cutting: The machine tool spindle drives the entire connected tool to cut and remove the welded stop according to the preset machining trajectory and parameters; during the machining process, the tool plate can move safely within a limited space while ensuring customized dimensions, and will never collide with the parts. S6. Separation and Removal: After machining is completed, the machine tool spindle stops rotating. The connection between the tool holder and the tool plate is released inside the space. First, the tool holder is removed, and then the tool plate that has completed the task is manually removed.

[0024] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical solutions, and technical solutions in this invention can be freely combined and used.

Claims

1. A special cutting tool for removing welded stops in the confined space of an aircraft engine, characterized in that: It includes a tool holder and a tool plate. The head of the tool holder is provided with a spindle interface (1-3) for connecting with the machine tool spindle. The tool plate is generally flat and has a cutting blade (7) at its end for removing the weld stop. The tool holder and the tool plate are connected by a connecting mechanism, and the connected tool holder and tool plate are generally L-shaped.

2. The special cutting tool for removing welded stops in the confined space of an aero-engine according to claim 1, characterized in that: The specific structure of the connecting mechanism is as follows: the tail of the tool holder is designed as a circular boss, with the central protruding part serving as a positioning block (1-1) and the peripheral recessed stepped part serving as a keyway. Inside the positioning block (1-1) are threaded holes B (1-2) arranged axially and A (1-4) arranged laterally. Correspondingly, the tool plate connecting head is designed as a groove with a stepped hole, the stepped hole being coaxial with the threaded hole. The circular groove on the upper side is used for... The positioning block (1-1) at the tail of the tool handle has a through hole on the lower side for fitting screw B (5); after the tail of the tool handle is connected to the head of the tool plate, screw B (5) is used to pass through the through hole and the circular groove of the tool plate in sequence and then locked into the threaded hole B (1-2) of the positioning block (1-1) to achieve locking of the tool handle and the tool plate; a key (4) is fitted in the keyway, and the key (4) is locked into the threaded hole A (1-4) of the positioning block (1-1) by a horizontally arranged screw A (3).

3. A special cutting tool for removing welded stops in the confined space of an aero-engine according to claim 2, characterized in that: The blade is designed as a left-type blade (2-1) and a right-type blade (2-2) according to the position of the weld stop. The left-type blade (2-1) is used to process the left weld stop (9-1) adjacent to the left side panel (8-1), and the right-type blade (2-2) is used to process the right weld stop (9-2) adjacent to the right side panel (8-2).

4. A special cutting tool for removing welded joints in the confined space of an aero-engine according to claim 3, characterized in that: The blade mounted on the left blade plate (2-1) has its tip positioned 0.5 mm higher than the blade plate body; the blade mounted on the right blade plate (2-2) has its tip positioned 1 mm higher than the blade plate body.

5. A machining method for removing welded stops within the confined space of an aero-engine, employing a special cutting tool as described in any one of claims 1-4, characterized in that... Includes the following steps: S1. Select the left-type blade (2-1) or the right-type blade (2-2) according to the position of the weld stop to be processed. S2 Individual blade insertion: Manually insert the selected blade through the inner hole of the flange into the narrow space where the welding stop to be processed is located; S3. Machine tool guide bar: The tool holder that has been installed on the machine tool spindle is precisely moved to the entrance of a narrow space through program control; S4. Internal connection: At the entrance of the narrow space, the connecting head of the blade plate is assembled and connected to the tail of the handle. By locking screw B (5), the handle is firmly and accurately connected to the blade plate that is placed in the narrow space. S5. Perform cutting: The machine tool spindle drives the entire connected tool to cut and remove the weld stop to be processed according to the preset machining trajectory and parameters; S6. Separation and Removal: After machining is completed, the machine tool spindle stops rotating. The connection between the tool holder and the tool plate is released inside the space. First, the tool holder is removed, and then the tool plate that has completed the task is manually removed.

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