A processing method for aircraft engine parts and a rectangular undercut processing tool

Abstract

The present invention proposes a processing method for aircraft engine parts and a rectangular tool for processing a recess, which includes firstly turning by lathe, then performing special surface treatment (strengthening treatment), and finally grinding the inner hole to size. During the fine turning process, a rectangular recess is turned at the corner where the bottom surface of the inner hole and the side wall are connected, and a special rectangular recess turning tool is used. The turning tool mainly consists of a blade H surface, a blade I surface, a blade J surface, a blade K surface, a blade L surface, a blade M surface, a blade N surface and a blade P surface connected in sequence in a counterclockwise direction. The present invention solves the problem that it is difficult to turn the bottom surface and the side wall of the inner hole to the design required size when the surface of the inner hole of the part has a strengthening layer, and further solves the problem that the rectangular recess cannot be accurately formed (in shape and size) by using an ordinary turning tool.

Description

Technical Field

[0001] The invention belongs to the technical field of turning, and in particular relates to a method for machining parts of an aerospace engine and a tool for turning a rectangular tool recess. Background Art

[0002] In order to improve the working performance of aircraft engines, some parts need to undergo special surface treatments, such as tinning, phosphating and nitriding. The above treatments will increase the surface hardness of the parts. It is difficult to machine the strengthened surface directly by turning.

[0003] like Figure 1 and Figure 2 As shown, it is a part drawing of an aircraft engine part. There is an inner hole in the part, and the bottom surface and side walls of the inner hole need to be surface strengthened. However, after the bottom surface and side walls of the inner hole form a strengthening layer surface, it is difficult to machine the inner hole to the required design size by simply relying on turning.

[0004] In view of the above problems, it is urgent to design a processing method that can quickly process the parts after surface strengthening treatment to the required design size. Summary of the invention

[0005] The present invention aims to provide a processing method for aircraft engine parts, which solves the problem that it is difficult to machine the bottom surface and side walls of the inner hole to the design required dimensions when the surface of the inner hole of the part has a strengthening layer. Furthermore, in view of the problem that the shape and size of the rectangular back cutter groove at the corner connecting the bottom surface of the inner hole and the inner wall are difficult to meet the requirements during the aforementioned processing method, a rectangular back cutter groove processing tool is designed, which can quickly process the back cutter groove to the required shape and size, with high processing efficiency and fast processing speed.

[0006] The present invention adopts the following technical solutions:

[0007] A tool for machining a rectangular undercut groove of an aero-engine part, comprising a blade,

[0008] The blade is mainly composed of a blade H surface, a blade I surface, a blade J surface, a blade K surface, a blade L surface, a blade M surface, a blade N surface and a blade P surface which are connected in sequence in a counterclockwise direction, and the blade H surface, the blade I surface, the blade J surface, the blade K surface, the blade L surface, the blade M surface, the blade N surface and the blade P surface are all perpendicular to the same reference plane;

[0009] There is a 45° angle between the blade H surface and the blade I surface;

[0010] There is an angle of 135° between the blade I surface and the blade J surface, and a first interval is formed between the blade J surface and the blade H surface;

[0011] There is an angle of 135° between the blade K surface and the blade J surface, and a second interval is formed between the blade K surface and the blade I surface;

[0012] The blade K surface is perpendicular to the blade L surface;

[0013] There is an angle of 135° between the blade L surface and the blade M surface;

[0014] There is an angle of 135° between the blade M surface and the blade N surface;

[0015] The blade N surface is parallel to the blade L surface, and a third interval is formed between the two;

[0016] There is an angle of 45° between the blade N surface and the blade P surface;

[0017] The connection between the blade I surface and the blade J surface, the connection between the blade J surface and the blade K surface, the connection between the blade K surface and the blade L surface, the connection between the blade L surface and the blade M surface, and the connection between the blade M surface and the blade N surface are rounded.

[0018] As an option, the first interval is larger than the second interval and the third interval, and the second interval and the third interval are equal.

[0019] As an option, the blade N surface is connected to the blade P surface through a right angle surface, and the right angle surface is perpendicular to the common reference plane of the blade N surface and the blade P surface. The function of the right angle surface is to prevent the blade P surface from colliding with the inner surface of the part.

[0020] As an option, the rectangular undercut processing tool for aircraft engine parts also includes a tool holder, the front end of which is rotatably connected to the blade via a clamping screw, and the angle between the blade P surface and the length direction of the tool holder is 45°.

[0021] A method for processing an aerospace engine part, wherein the part comprises an inner hole, and a surface strengthening layer is provided on the bottom surface and the side wall of the inner hole. The processing method comprises the following steps:

[0022] Step 1, turning the bottom surface and side wall of the inner hole to the designed process size, wherein the designed process size includes a grinding allowance;

[0023] Step 2: turning a tool-retracting groove at the corner where the bottom surface and the side wall of the inner hole connect;

[0024] Step 3, performing surface strengthening treatment on the bottom surface, side wall and undercut of the inner hole to generate a surface strengthening layer;

[0025] Step 4: Grind the surface strengthening layer on the bottom surface and side wall of the inner hole until the required size of the inner hole is reached.

[0026] As an option, in step 1,

[0027] The inner hole is machined to the process design size along the direction perpendicular to the inner hole bottom surface by using a D-type turning tool to form the inner hole bottom surface;

[0028] The inner hole is processed to the process design size along the direction perpendicular to the inner hole side wall by using a D-type turning tool to form the inner hole side wall.

[0029] It should be pointed out that D-type turning tool is a diamond-shaped tool.

[0030] As an option, in step 2, the tool retreat groove is a rectangular tool retreat groove, and there is a 45° bevel at the connection between the rectangular tool retreat groove and the bottom surface of the inner hole, and there is also a 45° bevel at the connection between the rectangular tool retreat groove and the side wall of the inner hole, and the corners of the rectangular tool retreat groove are rounded.

[0031] Furthermore, the aforementioned tool is used to turn a rectangular tool recess in a direction forming an angle of 45° with the side wall of the inner hole.

[0032] As an option, in step three, the surface strengthening treatment includes tinning, phosphating and nitriding.

[0033] Compared with the prior art, the present invention has the following characteristics:

[0034] (1) A new solution is provided for how to process parts with a strengthening layer to the required design dimensions;

[0035] (2) The problem that the corner connection cannot be machined by grinding is solved by designing a back-off groove at the corner where the bottom surface of the inner hole and the side wall are connected;

[0036] (3) A rectangular-section (with chamfers and bevels) undercut groove is preferred. On the one hand, the rectangular undercut groove facilitates feeding during grinding. On the other hand, the rectangular undercut groove better meets the aerodynamic layout of the part. Compared with other undercut grooves (spherical undercut grooves), more material can be removed while meeting the structural strength requirement. This is also an important means of lightweight engine design. However, the processing difficulty of the rectangular undercut groove is also greatly increased.

[0037] (4) In order to solve the problem that the rectangular tool recess has a complex cross-section, small size and is difficult to measure, a special tool was designed that can quickly and accurately process the rectangular tool recess to the required shape and size, thus meeting the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the undercut groove of an aerospace engine part of the present invention;

[0039] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the middle area Ⅰ;

[0040] Figure 3is a schematic diagram of a knife handle of the present invention;

[0041] Figure 4 It is a schematic diagram of a tool of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0043] like Figure 1 and Figure 2 As shown, the aircraft engine part to be processed in the present invention has an inner hole, and the bottom surface and side wall surface of the inner hole have a surface strengthening layer (such as a nitriding layer, a tin plating layer, a chromium plating layer, an oxidation phosphating layer, etc.). Figure 2 The letters G, F, E, and Ф represent different sizes of parts.

[0044] The basic processing idea of ​​the present invention is: firstly, fine turning is performed by turning, then special surface treatment (strengthening treatment) is performed, and finally, the inner hole is processed to size by grinding.

[0045] Since the bottom surface and the side wall of the inner hole are connected at a right angle, and it is difficult to remove the junction between the end face of the part and the hole surface (that is, the corner where the bottom surface and the side wall of the inner hole are connected) by grinding, a back cut is required at the junction to avoid this situation. Considering the convenience of feeding during grinding and the minimum impact on the part, the back cut adopts a more complex rectangular cross-section shape, such as Figure 2 As shown, there is a 45°±1° bevel at the connection between the rectangular tool retreat groove and the bottom surface of the inner hole, there is also a 45°±1° bevel at the connection between the rectangular tool retreat groove and the side wall of the inner hole, and the corners of the rectangular tool retreat groove are rounded R0.3±0.2.

[0046] If the rectangular back-cut groove is not turned completely, there will be a buildup at the junction of the end face and the hole surface (i.e. the corner where the bottom surface and the side wall of the inner hole connect), which will not only affect the subsequent spraying and grinding processes, but also affect the subsequent assembly. If the back-cut groove is overcut, it will affect the strength of the part and thus affect the performance of the entire engine.

[0047] At present, ball-type cutters are generally used for turning of back-cut grooves. Although back-cut grooves can be machined and meet the requirements of part assembly and mechanical properties, the shape and size of the back-cut grooves do not meet the design requirements of rectangular back-cut grooves. The machined back-cut groove is an approximate rectangular back-cut groove.

[0048] like Figure 3 and Figure 4The present invention designs a special-shaped rectangular undercut processing tool, the tool includes a blade, the blade length is 46mm, such as Figure 4 The blade is mainly composed of a blade H surface, an edge I surface, an edge J surface, an edge K surface, an edge L surface, an edge M surface, an edge N surface and a blade P surface which are connected in sequence in a counterclockwise direction, and the blade H surface, the blade I surface, the blade J surface, the blade K surface, the blade L surface, the blade M surface, the blade N surface and the blade P surface are all perpendicular to the same reference plane, and the width distance between the blade H surface and the blade P surface is 5mm; there is a 45° angle between the blade H surface and the blade I surface; there is a 135° angle between the blade I surface and the blade J surface, and a first interval is formed between the blade J surface and the blade H surface, and the first interval is the vertical distance between the blade J surface and the blade H surface, which is 2mm in this embodiment; there is a 135° angle between the blade K surface and the blade J surface, and the blade K surface is close to the blade A second interval is formed between the blade I surfaces, and the second interval is the vertical distance between the blade K surface and the blade I surface, which is 1mm in this embodiment; the blade K surface is perpendicular to the blade L surface; there is an angle of 135° between the blade L surface and the blade M surface; there is an angle of 135° between the blade M surface and the blade N surface; the blade N surface is parallel to the blade L surface, and a third interval is formed between the two, and the third interval is the vertical distance between the blade N surface and the blade L surface, which is 1mm in this embodiment; there is an angle of 45° between the blade N surface and the blade P surface; the connection between the blade I surface and the blade J surface, the connection between the blade J surface and the blade K surface, the connection between the blade K surface and the blade L surface, the connection between the blade L surface and the blade M surface, and the connection between the blade M surface and the blade N surface have a rounded corner of R0.3. The blade N surface and the blade P surface are connected by a right-angled surface, and the right-angled surface is perpendicular to the common reference plane of the blade N surface and the blade P surface, such as Figure 4 , right angle surface length 5.5mm.

[0049] like Figure 3 The tool is clamped on the tool holder at an angle of 45°, that is, the angle between the blade P surface of the blade and the tool holder is 45°.

[0050] like Figure 1 As shown, the processing method of aircraft engine parts includes the following steps:

[0051] Step 1: Turn the bottom surface and side wall of the inner hole to the designed process size, wherein the designed process size includes the grinding allowance, wherein a D-type turning tool is used along the direction perpendicular to the bottom surface of the inner hole ( Figure 1 The inner hole is processed to the process design size (in the A direction) to form the bottom surface of the inner hole; a D-type turning tool is used to turn the inner hole in the direction perpendicular to the side wall of the inner hole ( Figure 1 (B direction) the inner hole is processed to the process design size to form the inner hole side wall;

[0052] Step 2: Use the aforementioned tool (rectangular undercut processing tool) to cut along the direction with a 45° angle to the side wall of the inner hole ( Figure 1The C direction is at an angle of 45° to the end face, and the C direction is parallel to Figure 4 The H surface of the middle blade or the P surface of the blade is turned into a tool-relief groove at the corner where the bottom surface and the side wall of the inner hole are connected. The tool-relief groove is a rectangular tool-relief groove. There is a 45°±1° bevel at the connection between the rectangular tool-relief groove and the bottom surface of the inner hole, and there is also a 45°±1° bevel at the connection between the rectangular tool-relief groove and the side wall of the inner hole. The corner of the rectangular tool-relief groove is rounded with a radius of R0.3±0.2;

[0053] Step 3, performing surface strengthening treatment on the bottom surface, side wall and rectangular undercut of the inner hole to generate a surface strengthening layer;

[0054] Step 4: Grind the surface strengthening layer on the bottom surface and side wall of the inner hole until the required size of the inner hole is reached.

[0055] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For ordinary technicians in the field of this technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A tool for processing rectangular undercut grooves of aircraft engine parts, characterized by: Including blade, The blade is mainly composed of a blade H surface, a blade I surface, a blade J surface, a blade K surface, a blade L surface, a blade M surface, a blade N surface and a blade P surface which are connected in sequence in a counterclockwise direction, and the blade H surface, the blade I surface, the blade J surface, the blade K surface, the blade L surface, the blade M surface, the blade N surface and the blade P surface are all perpendicular to the same reference plane; There is a 45° angle between the blade H surface and the blade I surface; There is an angle of 135° between the blade I surface and the blade J surface, and a first interval is formed between the blade J surface and the blade H surface; There is an angle of 135° between the blade K surface and the blade J surface, and a second interval is formed between the blade K surface and the blade I surface; The blade K surface is perpendicular to the blade L surface; There is an angle of 135° between the blade L surface and the blade M surface; There is an angle of 135° between the blade M surface and the blade N surface; The blade N surface is parallel to the blade L surface, and a third interval is formed between the two; There is an angle of 45° between the blade N surface and the blade P surface; The connection between the blade I surface and the blade J surface, the connection between the blade J surface and the blade K surface, the connection between the blade K surface and the blade L surface, the connection between the blade L surface and the blade M surface, and the connection between the blade M surface and the blade N surface are rounded.

2. A rectangular undercut machining tool for aircraft engine parts according to claim 1, characterized in that: The first interval is larger than the second interval and the third interval, and the second interval is equal to the third interval.

3. A rectangular undercut machining tool for aircraft engine parts according to claim 1, characterized in that: The blade N surface is connected to the blade P surface via a right-angle surface, and the right-angle surface is perpendicular to a common reference plane of the blade N surface and the blade P surface.

4. A rectangular undercutting groove machining tool for aircraft engine parts according to claim 1, characterized in that: It also includes a handle, the front end of which is rotatably connected to the blade via a clamping screw, and the angle between the blade P surface and the length direction of the handle is 45°.

5. A method for processing an aerospace engine part, wherein the part comprises an inner hole, and a surface strengthening layer is provided on the bottom surface and the side wall of the inner hole, characterized in that: The processing method comprises the following steps, Step 1, turning the bottom surface and side wall of the inner hole to the designed process size, wherein the designed process size includes a grinding allowance; Step 2, turning a back cutter groove at the corner where the bottom surface and the side wall of the inner hole connect; Step 3, performing surface strengthening treatment on the bottom surface, side wall and undercut of the inner hole to generate a surface strengthening layer; Step 4, grinding the surface strengthening layer on the bottom surface and side wall of the inner hole until the required size of the inner hole is reached; In the step 2, the tool retreat groove is a rectangular tool retreat groove, and there is a 45° bevel at the connection between the rectangular tool retreat groove and the bottom surface of the inner hole, and there is also a 45° bevel at the connection between the rectangular tool retreat groove and the side wall of the inner hole. The corners of the rectangular tool retreat groove are rounded, and the tool described in claim 1 is used to turn the rectangular tool retreat groove in a direction with an angle of 45° to the side wall of the inner hole.

6. The method for processing an aerospace engine part according to claim 5, characterized in that: In the step 1, The inner hole is machined to the process design size along the direction perpendicular to the inner hole bottom surface by using a D-type turning tool to form the inner hole bottom surface; The inner hole is processed to the process design size along the direction perpendicular to the inner hole side wall by using a D-type turning tool to form the inner hole side wall.

7. The method for processing aircraft engine parts according to claim 5, characterized in that: In the step three, the surface strengthening treatment includes tinning, phosphating and nitriding.

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