A method for processing thin-wall end gear ring

Abstract

A method for processing a thin-walled end gear ring, in the field of aviation thin-walled parts processing technology, includes the following steps: step 1: controlling deformation, step 1.1: determining the clamping scheme and blank structure, step 1.2: determining the processing scheme, step 1.3: selecting tools; step 2: selecting equipment; step 3: compiling CNC programs to compile turning cycles, ratchet milling and cutting programs; step 4: parts processing, running CNC programs, completing turning, milling and cutting processes, and completing parts processing by clamping the parts once. After the thin-walled end gear ring is processed by the method of the present invention, the problem of local replacement of certain engine parts is solved, and the problem of the whole machine being unable to be repaired due to the wear of parts and the need to import replacement parts is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation thin-walled parts processing, and in particular relates to a thin-wall end gear ring processing method. Background Art

[0002] The main shaft front locking seat assembly of a certain type of aircraft engine is installed in the central transmission housing of the engine to control the precision transmission parts. The single part in this assembly is the end gear ring. The end gear ring part has a thin wall and many end face ratchets. The end face flatness error requirement is strict. The end gear ring structure is as follows Figure 1 As shown, it plays a vital role in the engine.

[0003] The end tooth ring has an axial width of 5mm and a wall thickness of only 1.08mm at its thinnest point. There are 222 40° ratchets on the annular end face, with one side of the vertical face always pointing to the center of the ring. The narrowest part of the ratchets is only 0.3mm, and the root is rounded R0.25max. The flatness of the top surface of the ratchets is only 0.05mm. Due to the thin wall thickness of the part, it is easy to deform during processing, and the flatness of the end face is difficult to ensure. The bottom surface of the end face ratchets is narrow, and the inclined surface is in an unfolded shape, which increases the difficulty of equipment selection and tool selection. Summary of the invention

[0004] The purpose of the present invention is to provide a method for processing a thin-walled end gear ring. By utilizing this technology, it is possible to successfully solve the problem of a certain engine having to have local replacement parts for repair, and to solve the problem that the entire engine cannot be repaired due to the need to import replacement parts due to wear of parts.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for processing a thin-wall end gear ring comprises the following steps:

[0007] Step 1: Controlling deformation

[0008] Step 1.1: Determine the clamping scheme and blank structure

[0009] Since the part is a thin-walled structure with a short axial width and a small ring end area, a process table is added as a supporting part; the axial length of the blank is determined according to the total width of the part, the width of the cutting knife and the allowance of the flat end face; based on the factors of the allowance cutting, the blank structure is determined to be an annular blank structure;

[0010] Step 1.2: Determination of processing plan

[0011] Rough turning of the oxide layer on the inner and outer surfaces of the blank, first flatten the end face as a reference for measuring the size, then turn a ring groove I on the outer surface of the blank near the end face of the chuck, thereby cutting off the deformation extension surface transmitted from the clamping part and reducing the influence of the clamping force;

[0012] Then, the outer contour is roughly machined according to the structural dimensions of the part, and an annular groove II with inner and outer symmetry is machined at the cut-off end of the part. When the part is cut off after fine machining, the deformation stress caused by the cutting resistance on the part is ensured;

[0013] Step 1.3: Tool selection

[0014] Select machining tools according to the part structure; in order to ensure that the individual tooth shape does not deform, the tool material is made of cemented carbide, and the cutting edge angle is kept small, thereby avoiding tooth deformation and end face yield deformation;

[0015] Step 2: Equipment Selection

[0016] According to the structural characteristics of the parts, the turning of the part contour and the milling of the ratchet features are completed at the same time, so a turning-milling composite machining center is used;

[0017] Step 3: Prepare the CNC program

[0018] Program turning cycles, ratchet milling and cut-off procedures;

[0019] Step 4: Parts Processing

[0020] Run the CNC program to complete the turning, milling and cutting processes, and complete the part processing by clamping the part once.

[0021] In step 3, the turning cycle, ratchet milling and cutting programs are compiled, and the ratchet milling program is compiled as follows:

[0022] In order to avoid the phenomenon of accumulated indexing errors and the inability to meet the width requirements of the first and last teeth, the original angle parameter assignment is changed to a formula substitution method, that is, c1=360 / 222, and the variable c1 is brought into the program line of the angle command C=c1. The CNC program is used to control the indexing accuracy, thereby controlling the position accuracy of each tooth and reducing the accumulated error.

[0023] In step 4, the parts are processed by running the CNC program to complete the turning, milling and cutting processes. The parts are processed by clamping the parts once, specifically:

[0024] Step 4.1: Rough turning. The turning cycle is mainly for the processing of part contours. The required tools include external turning tools, internal hole turning tools and ring groove turning tools. In order to reduce the deformation caused by cutting force during turning, the external turning tool is used to rough the outer contour first, then the internal hole turning tool is used to rough the inner contour, and finally the ring groove turning tool is used to process the ring groove I and ring groove II, and the cutting depth each time is not more than 0.2mm.

[0025] Step 4.2: Milling

[0026] The milling process of the ratchet is divided into three steps: rough machining, semi-finishing and finishing. Each time a circle is completely machined, the next step of machining is carried out to make the ratchet tooth thickness consistent and evenly distributed. At the same time, the cutting depth of each cut is controlled by the CNC program to ensure that the end surface flatness is within 0.03mm;

[0027] Step 4.3, finishing machining, again finishing machining the outer contour and inner contour by using the external turning tool and the internal hole turning tool;

[0028] Step 4.4: Cutting: Use a ring groove turning tool for cutting. Use internal and external bidirectional cutting to prevent uneven force on parts during unidirectional cutting.

[0029] The technical effects of the present invention are:

[0030] After the thin-walled end gear ring is processed by the method of the present invention, the problem of the need for local replacement of certain engine parts for repair is solved, and the problem of the whole machine being unable to be repaired due to the need to import replacement parts due to wear of parts is solved. The cost of a single end gear ring is 5,000 yuan, the number of a single unit is pieces, the annual repair volume is 200 units, and the annual cost saving is: 5,000×1×200=1 million yuan. This technology can be applied to the processing of thin-walled parts of various models of engines, and has a wide range of promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The schematic diagram of the end gear ring structure of the present invention, wherein Figure 1 a is a schematic diagram of parts; Figure 1 b is Figure 1 Schematic diagram of direction B of a; Figure 1 c is Figure 1 b Local enlarged schematic diagram; Figure 1 d is Figure 1 a AA-direction schematic diagram;

[0032] Figure 2 Schematic diagram of the processing of the ring groove for preventing deformation of the parts of the present invention;

[0033] Figure 3 Schematic diagram of the ratchet tool of the present invention; DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0035] A method for processing a thin-wall end gear ring comprises the following steps:

[0036] Step 1: Controlling deformation

[0037] Step 1.1: Determine the clamping scheme and blank structure

[0038] Since the part has a thin-wall structure, short axial width and small ring end area, it is not conducive to the single-piece radial clamping and axial clamping clamping methods, so an additional process table is used as the clamping part;

[0039] According to the total width of the part, the width of the cutting knife and the allowance of the flat end face, the axial length of the blank is determined to be 40mm; considering the cutting of less allowance, the blank structure is determined to be an annular blank structure with an outer diameter of 124mm, an inner hole diameter of 90mm and a width of 40mm;

[0040] Step 1.2: Determination of processing plan

[0041] Roughly turn the oxide layer on the inner and outer surfaces of the blank, clamp one end to smooth the surface, the clamping length in this embodiment is 10 mm, and turn the other end;

[0042] First, the end face is flattened as a reference for measuring the size. Then, a 3mm wide annular groove I is machined on the outer surface of the part near the end face of the chuck, thereby cutting off the deformation extension surface transmitted from the clamping part, releasing the clamping force and cutting stress, and reducing the influence of the clamping force.

[0043] Then, the outer contour is roughly machined according to the structural dimensions of the part, and an annular groove II is machined that is symmetrical inside and outside at the cut-off end of the part. In this embodiment, the wall thickness of the annular groove II is 2 mm, and the width of the annular groove is 6 mm. When the part is cut off after fine machining, the deformation stress caused by the cutting resistance on the part is ensured; and then the part is finely machined; Figure 2 As shown;

[0044] Step 1.3: Tool selection

[0045] The machining tool is selected according to the structure of the part, and the tool for machining the end face ratchet is relatively special; according to the end face ratchet characteristics of the part, forming processing is adopted, but considering the structural characteristics of each single tooth, it is necessary to keep the single tooth shape from being deformed, so the tool material is selected from a cemented carbide material with high cutting performance, and at the same time, a tool with a smaller cutting edge angle is selected to reduce the cutting resistance, thereby avoiding tooth deformation and end face yield deformation; in this embodiment, the tool for machining the end face ratchet adopts a special ratchet tool, such as Figure 3 As shown;

[0046] Step 2: Equipment Selection

[0047] According to the part structure, it is necessary to complete the turning of the part contour and the milling of the ratchet feature at the same time. Therefore, the equipment adopts a turning and milling composite machining center to complete turning, milling and cutting by clamping the part once.

[0048] Step 3: Prepare the CNC program

[0049] According to the turning-milling-cutting steps, the turning cycle and milling cycle programs are compiled. The ratchet milling program has special requirements, specifically:

[0050] Since the part has 222 ratchet teeth evenly distributed on the circumferential end face, the tool should rotate 1.621621° each time the part is processed. If the angle value is accurate to three decimal places during programming, the indexing error will accumulate and the width requirements of the first and last teeth cannot be met, thus affecting the position requirement of 0.15mm. Therefore, it is necessary to change the angle parameter assignment to the formula substitution method, that is, c1=360 / 222, and bring the variable c1 into the program line of the angle command C=c1, and use the CNC program to control the indexing accuracy, thereby controlling the position accuracy of each tooth and reducing the cumulative error.

[0051] Step 4: Parts Processing

[0052] Step 4.1: Rough turning. The turning cycle is mainly for the processing of part contours. The required tools include external turning tools, internal hole turning tools and ring groove turning tools. In order to reduce the deformation caused by cutting force during turning, the external turning tool is used to rough the outer contour first, and then the internal hole turning tool is used to rough the inner contour. Finally, the ring groove turning tool is used to process the ring groove I and ring groove II, and the cutting depth each time is not more than 0.2mm. The external turning tool model is CNMG120404, the internal hole turning tool model is CCMT09T302, and the ring groove turning tool model is GIP3.0-0.4.

[0053] Step 4.2: Milling

[0054] The milling process of the ratchet is divided into three steps: rough machining, semi-finishing and finishing. Each time a circle is completely machined, the next step of machining is carried out to make the ratchet tooth thickness consistent and evenly distributed. At the same time, the cutting depth of each cut is controlled by the CNC program to ensure that the end surface flatness is within 0.03mm;

[0055] Step 4.3, finishing machining, again finishing machining the outer contour and inner contour by using the external turning tool and the internal hole turning tool;

[0056] Step 4.4: Cutting: Use a ring groove turning tool for cutting. Use internal and external bidirectional cutting to prevent uneven force on parts during unidirectional cutting.

Claims

1. A method for processing a thin-walled end gear ring, characterized in that: The steps include: Step 1: Controlling deformation Step 1.1: Determine the clamping scheme and blank structure Since the part is a thin-walled structure with a short axial width and a small ring end area, a process table is added as a supporting part; the axial length of the blank is determined according to the total width of the part, the width of the cutting knife and the allowance of the flat end face; based on the factors of the allowance cutting, the blank structure is determined to be an annular blank structure; Step 1.2: Determination of processing plan Rough turning of the oxide layer on the inner and outer surfaces of the blank, first flatten the end face as a reference for measuring the size, then turn a ring groove I on the outer surface of the blank near the end face of the chuck, thereby cutting off the deformation extension surface transmitted from the clamping part and reducing the influence of the clamping force; Then, the outer contour is roughly machined according to the structural dimensions of the part, and an annular groove II with inner and outer symmetry is machined at the cut-off end of the part. When the part is cut off after fine machining, the deformation stress caused by the cutting resistance on the part is ensured; Step 1.3: Tool selection Select machining tools according to the part structure; in order to ensure that the individual tooth shape does not deform, the tool material is made of cemented carbide, and the cutting edge angle is kept small, thereby avoiding tooth deformation and end face yield deformation; Step 2: Equipment Selection According to the structural characteristics of the parts, the turning of the part contour and the milling of the ratchet features are completed at the same time, so a turning-milling composite machining center is used; Step 3: Prepare the CNC program Program turning cycles, ratchet milling and cut-off procedures; Step 4: Parts Processing Run the CNC program to complete the turning, milling and cutting processes, and complete the part processing by clamping the part once.

2. A method for processing a thin-walled end gear ring according to claim 1, characterized in that: In step 3, the turning cycle, ratchet milling and cutting programs are compiled, and the ratchet milling program is compiled as follows: In order to avoid the phenomenon of accumulated indexing errors and the inability to meet the width requirements of the first and last teeth, the original angle parameter assignment is changed to a formula substitution method, that is, c1=360 / 222, 222 is the number of teeth on the gear ring, and c1 is substituted into the program line of the angle command C=c1. The CNC program is used to control the indexing accuracy, thereby controlling the position accuracy of each tooth and reducing the accumulated error.

3. A method for processing a thin-walled end gear ring according to claim 1, characterized in that: In step 4, the parts are processed by running the CNC program to complete the turning, milling and cutting processes. The parts are processed by clamping the parts once, specifically: Step 4.1: Rough turning. The turning cycle is mainly for the processing of part contours. The required tools include external turning tools, internal hole turning tools and ring groove turning tools. In order to reduce the deformation caused by cutting force during turning, the external turning tool is used to rough the outer contour first, then the internal hole turning tool is used to rough the inner contour, and finally the ring groove turning tool is used to process the ring groove I and ring groove II, and the cutting depth each time is not more than 0.2mm. Step 4.2: Milling The milling process of the ratchet is divided into three steps: rough machining, semi-finishing and finishing. Each time a circle is completely machined, the next step of machining is carried out to make the ratchet tooth thickness consistent and evenly distributed. At the same time, the cutting depth of each cut is controlled by the CNC program to ensure that the end surface flatness is within 0.03mm; Step 4.3, finishing machining, again finishing machining the outer contour and inner contour by using the external turning tool and the internal hole turning tool; Step 4.4: Cutting: Use a ring groove turning tool for cutting. Use internal and external bidirectional cutting to prevent uneven force on parts during unidirectional cutting.

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