A method of closing a segmented engine frame

Abstract

The application relates to a method for closing a segmented engine frame and belongs to the technical field of engine frames. The method comprises the following steps: rough machining a first small end surface of a first section, turning over, fine machining a first large end surface and a first connecting surface, and machining a first positioning pin hole group and a first process pin hole group; turning over again to make the first small end surface face upward, establishing a first reference, and measuring the positions of the first positioning pin hole group and the first process pin hole group; rough machining a second small end surface of a second section, turning over, fine machining a second large end surface and a second connecting surface; turning over again to make the second small end surface face upward, machining a second positioning pin hole group and a second process pin hole group according to the measurement result; and connecting the first connecting surface and the second connecting surface through process pins. The pin hole positions on the first connecting surface and the second connecting surface are strictly symmetrical, and deformation errors are avoided, so that the fine machining surface before closing can still meet the drawing requirements after closing.

Description

Technical Field

[0001] This invention belongs to the field of engine frame technology, specifically relating to a method for assembling a segmented engine frame. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The engine mainframe, also known as the engine frame, is a crucial component of the engine crankcase. Due to their enormous size, large marine engines require engine frames to be manufactured using various processing methods, including welding. To avoid the adverse effects of long, continuous welds on product quality (including welding deformation and stress concentration), a segmented manufacturing method is employed. Specifically, the engine frame is divided into multiple frame segments along its length. The upper end of each segment is a small end face, and the lower end is a large end face. The contact surfaces between the frame segments are called connecting surfaces, which are substantially perpendicular to the small and large end faces. After manufacturing each frame segment separately, the connecting surfaces of the multiple frame segments are assembled and machined to ensure the overall dimensional requirements of the small end faces and the frame are met.

[0004] The machined surfaces are distributed across various locations within the frame sections, necessitating the flipping and reversing of multiple sections. During this process, uncontrollable material deformation errors can easily lead to the assembled product failing to meet the drawing requirements. Therefore, designing a manufacturing process that improves production efficiency while maintaining precision has become a challenge for technical personnel. Summary of the Invention

[0005] To address the problem of difficulty in ensuring the accuracy of the assembly process, the present invention aims to provide a manufacturing method for a segmented engine frame. By selecting a reasonable positioning reference and processing the positioning pin holes and process pin holes on the connecting surface of one frame segment according to the data of the positioning pin holes and process pin holes, the accuracy of the assembly process can be guaranteed, and the accuracy of subsequent processing can be guaranteed.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A method for manufacturing a segmented engine frame includes the following steps:

[0008] S1. Roughly machine the surface of the first small end of the first section of the segmented engine frame, flip it so that the first large end face is facing up, and then finely machine the first large end face and the first connecting face, and machine the first positioning pin hole group and the first process pin hole group on the first connecting face.

[0009] S2. Flip the first segment so that the first small end face is facing upwards, establish a first reference using the positional dimensions including the first large end face and the first connecting surface, and measure the positional dimensions of the first positioning pin hole group and the first process pin hole group.

[0010] S3. Roughly machine the surface of the second small end of the second section of the segmented engine frame, flip it so that the second large end face is facing up, and then finish machine the second large end face and the second connecting surface.

[0011] S4. Flip the second segment so that the second small end face is facing up. Establish a second reference basis using the positional dimensions of the second large end face and the second connecting surface. Based on the positional dimensions of the first positioning pin hole group and the first process pin hole group measured in S2, process the second positioning pin hole group and the second process pin hole group of the second segment.

[0012] S5. Connect the first connecting surface and the second connecting surface using process pins and locating pins.

[0013] Optionally, in S1, the side position of the first large end face is the first process reference surface, so that the first process reference surface, the first large end face and the first connecting surface are perpendicular to each other.

[0014] Optionally, in S1, the first locating pin hole group includes multiple first locating pin holes; the first process pin hole group includes multiple first process pin holes.

[0015] Optionally, in S2, a first reference is established using the first large end face, the first connecting face, and the first process reference face.

[0016] Optionally, in S3, the side position of the second large end face is used as the reference surface for the second process, so that the second process reference surface, the second large end face, and the second connecting surface are perpendicular to each other.

[0017] Optionally, in S3, the relative positions of the second process reference surface and the second large end face are symmetrical to the relative positions of the first large end face and the first process reference surface, so that the positions of the second process reference surface and the first process reference surface are relative after closing.

[0018] Optionally, in S3, the second connecting surface is oriented opposite to the first connecting surface on the processing equipment.

[0019] Optionally, in S4, a second reference is established using the second large end face, the second connecting face, and the second process reference face.

[0020] Optionally, in S4, the second locating pin hole group includes multiple second locating pin holes; the second process pin hole group includes multiple second process pin holes.

[0021] Optionally, in S4, the positions of the second positioning pin hole group and the second process pin hole group relative to the second reference are symmetrical with respect to the first positioning pin hole group and the first process pin hole group relative to the first reference, both horizontally and vertically, so that after closing, the positions of the second positioning pin hole group and the first positioning pin hole group are opposite to each other, and the positions of the second process pin hole group and the first process pin hole group are opposite to each other.

[0022] Optionally, in S5, multiple process pins are used to connect the first process pin hole group and the second process pin hole group, and the process pins are respectively interference-fitted with the first process pin hole and the second process pin hole.

[0023] Optionally, the following steps are also included: S6, using bolts to connect the first segment and the second segment, and reducing the gap between the first connecting surface and the second connecting surface by tightening the bolts, so that the gap is smaller than the set size.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. In the manufacturing method of the segmented engine frame of the present invention, the finished product surface is selected as the reference, and the second process pin hole group and the first positioning pin hole group are processed according to the actual position size of the first process pin hole group and the first positioning pin hole group, so that the pin hole positions on the first connecting surface and the second connecting surface are strictly symmetrical. The process pin holes and positioning pin holes are processed in the state of the first segment and the large end of the second segment facing downwards, respectively, to avoid uncontrollable deformation errors caused by material deformation and other reasons during the process, so as to make the closing size accurate, and to ensure that the finished surface before closing can still meet the drawing requirements after closing.

[0026] 2. The present invention has a reasonable process design, with a small machining allowance before closure, which reduces the amount of machining work after closure, reduces the difficulty of processing and manufacturing, and greatly improves production efficiency. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a flowchart of the processing method for the first segment in Example 1.

[0029] Figure 2 This is a flowchart of the processing method for the second segment in Example 1.

[0030] Figure 3 This is a schematic diagram of the surface of the first small end of the first segment in Example 1.

[0031] Figure 4 This is a schematic diagram of the first large end face and the first connecting face of the first segment in Embodiment 1.

[0032] Figure 5 This is a schematic diagram of the posture of the first segment of step S2 in Example 1.

[0033] Figure 6 This is a schematic diagram of the surface of the first small end of the second enzymatic hydrolysis segment in Example 1.

[0034] Figure 7 This is a schematic diagram of the second large end face and the second connecting face of the second segment in Example 1.

[0035] Figure 8 This is a schematic diagram of the posture of the second segment in step S4 of Example 1.

[0036] Figure 9 This is an assembly diagram of the first and second segments in Example 1.

[0037] Figure 10 In Example 1 Figure 9 A schematic diagram of part A.

[0038] Figure 11 In Example 1 Figure 9 A schematic diagram of part D.

[0039] Figure 12 In Example 1 Figure 9 A schematic diagram of part C.

[0040] Figure 13 In Example 1 Figure 9 A schematic diagram of Part B.

[0041] Figure 14 This is a schematic diagram illustrating the complementary relationship between the processed surfaces in Example 1.

[0042] Figure 15 This is a schematic diagram showing the relative positions of the first reference, the first locating pin hole group, and the first process pin hole group in Example 1.

[0043] Figure 16 This is a schematic diagram showing the relative positions of the second reference, the second locating pin hole group, and the second process pin hole group in Example 1.

[0044] Among them, 1. First segment; 11. First small end face; 12. First large end face; 13. First connecting surface; 14. First reference; 15. First positioning pin hole; 16. First process pin hole; 2. Second segment; 21. Second small end face; 22. Second large end face; 23. Second connecting surface; 24. Second reference; 25. Second positioning pin hole; 26. Second process pin hole. Detailed Implementation

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] To ensure quality, ultra-large marine engine frames (such as the main engine frame of the 9X92DF-2.0-iCER main engine) are designed with a segmented structure, including an output end section (hereinafter referred to as the first section) and a free end section (hereinafter referred to as the second section). To meet the drawings and subsequent assembly requirements, key parts need to be assembled together before machining (for example, guide rails need to be machined uniformly to ensure consistent dimensional and positional tolerances) to ultimately meet the drawings and assembly requirements. The small end of the main engine frame is used to connect the cylinder block, and the large end is used to connect the engine base. Therefore, both the large and small end faces on the first and second sections need to ensure high machining accuracy: if the large end face is machined uniformly after assembly, it will not meet the machining requirements of the internal structure of the frame, and the machining after assembly requires connection and disassembly, resulting in excessive workload and severely reducing production efficiency; if the small end is machined before assembly, it is necessary to ensure that the finished surface still meets the drawing requirements after assembly, which places extremely high precision requirements on the assembly process. Other segmented engine frames face the same problem.

[0048] The machining equipment used in the following text is a machining center (Coburg gantry milling machine, model: PowerTec7000AG-S20). Before machining, the accuracy of the equipment was checked using a laser interferometer to ensure that it met the accuracy requirement of 0.02 / 1000. All machining was completed on the same machine to reduce the influence of external factors such as time, temperature, and humidity.

[0049] In the following text, the surface processing steps include roughing and finishing. Roughing is a processing method that leaves a processing allowance of 2 to 3 mm. Finishing is the final processing step for the surface. After finishing, the product surface meets the requirements of the drawing.

[0050] Example 1

[0051] The assembly method for the segmented engine frame includes the following steps (the processing method for the first segment is as follows). Figure 1As shown, including steps S1 and S2, the processing method of the second segment is as follows: Figure 2 As shown, this includes steps S3 and S4):

[0052] Step 1, such as Figure 3 As shown, the first section 1 of the segmented engine frame is mounted on a machining center, with the first connecting surface facing the X- direction. The surface of the first small end face 11 is then rough-machined (leaving a 2mm allowance), as follows: Figure 4 As shown, after flipping the first large end face 12 upwards, the first connecting surface 13 faces the X+ direction. The first large end face 12 and the first connecting surface 13 are then precision machined into the product surface. Next, the side edge of the first large end face 12 is machined as the first process reference surface. The first process reference surface, the first large end face 12, and the first connecting surface 13 are made perpendicular to each other. Specifically: machining the side edge of the first large end face is the Y-axis reference; machining the first connecting surface 13 along the length of the first large end face 12 is the X-axis reference; and machining the first large end face 12 is the Z-axis reference. These three references serve as the basis for setting the reference after flipping. Then, as shown... Figure 15 As shown, the first large end face 12, the first connecting face 13, and the first process reference face can serve as the first reference 14; the first locating pin hole group and the first process pin hole group are machined on the first connecting face 13 to the product dimensions required by the drawing; the first locating pin hole group includes multiple first locating pin holes 15; the first process pin hole group includes multiple first process pin holes 16, the first locating pin holes 15 are used for the four corners of the workpiece of the first segment 1 and the second segment 2, and are distributed at the four corners of the first connecting face; the first process pin holes 16 are used to increase the area of ​​the four corners positioning, and are distributed at the four corners of the first connecting face 13.

[0053] S2, such as Figure 5 As shown, the first segment 1 is flipped so that the first small end face 11 faces upward and placed on a level box, so that the measuring device can collect the position information of the first large end face 12 facing downward. Figure 15 As shown, a first reference 14 is established using the first large end face 12, the first connecting surface 13 and the first process reference surface, and the positional dimensions of the first positioning pin hole group and the first process pin hole group are measured based on the first reference 14.

[0054] S3, such as Figure 6 As shown, the second section 2 of the segmented engine frame is mounted on a machining center, with the second connecting surface facing the X+ direction. The surface of the second small end face 21 is then rough-machined (leaving a 2mm allowance), as follows: Figure 7As shown, after flipping the second large end face 22 upwards, the second connecting surface 23 faces the X-direction. The second large end face 22 and the second connecting surface 23 are then precision machined into the product surface. Next, the side edge of the second large end face 22 is machined as the second process reference surface, ensuring that the second process reference surface, the second large end face 22, and the second connecting surface 23 are perpendicular to each other. That is: machining the side edge of the second large end face is the Y-direction reference, machining the second connecting surface 23 along the length of the second large end face 22 is the X-direction reference, and machining the second large end face 22 is the Z-direction reference. These three references serve as the basis for setting the reference after flipping. Furthermore, the relative position of the second process reference surface and the second large end face 22 is symmetrical to the relative position of the first large end face 23 and the first process reference surface. Then, as shown... Figure 16 As shown, the second large end face 22, the second connecting face 23, and the second process reference face can become the second reference 24, and the second reference 24 is symmetrical about the left and right relative to the first reference 14, so that the positions of the second reference 24 and the first reference 14 are relative after closing.

[0055] S4, such as Figure 8 As shown, the second segment 2 is flipped so that the second small end face 21 faces upward. A second reference 24 is established using the second large end face 22, the second connecting surface 23, and the second process reference surface. Using the second reference 24 as the machining reference, and based on the positional dimensions of the first locating pin hole group and the first process pin hole group collected in S2, the second locating pin hole group and the second process pin hole group of the second segment 2 are machined on the second connecting surface 23 to the product dimensions required in the drawing. The second locating pin hole group includes multiple second locating pin holes 25; the second process pin hole group includes multiple second process pin holes 26. The positions of the second locating pin hole group and the second process pin hole group relative to the second reference 24 are symmetrical to the positions of the first locating pin hole group and the first process pin hole group relative to the first reference 14. Figure 15 The dimensions m1 and Figure 16 The m2 dimensions are consistent, and Figure 15 The dimensions n1 and Figure 16 The n2 dimensions are consistent, so that the second positioning pin hole group and the first positioning pin hole group are in opposite positions after closing, and the second process pin hole group and the first process pin hole group are in opposite positions.

[0056] S5, such as Figure 9 As shown, the first connecting surface 13 and the second connecting surface 23 are connected as one unit: multiple process pins are used to connect the first process pin hole group and the second process pin hole group, and the process pins are respectively interference-fitted with the first process pin hole and the second process pin hole to ensure that the interference amount of the first process pin hole and the second process pin hole is consistent; the assembly of the process pins adopts liquid nitrogen cold assembly process.

[0057] S6. Use locating pin holes to install in the first locating pin hole 15 and the second locating pin hole 25 respectively to achieve positioning installation. The remaining unmarked holes are bolt mounting holes. When connecting two sections, place shims under the two workpiece sections to ensure that the bottom surface reference is consistent (Z direction). By adjusting the lifting posture, align the pin holes of the first section 1 and the second section 2 (Y direction) to connect the locating pin holes and process pin holes. After positioning, the connection is as follows. Figure 9 As shown, by bolt installation, the first segment 1 and the second segment 2 are gradually brought closer together, so that the assembly gap x (X direction) between the first connecting surface 13 and the second connecting surface 23 is less than the set size (0.02mm feeler gauge cannot be inserted).

[0058] During the process, such as Figure 10 As shown, because there is a certain deviation between the actual machined surface and the theoretical surface of the processing equipment, therefore Figure 9 The actual plane at position A is offset to the right from the theoretical plane. Therefore, the first connecting plane 13 is oriented towards the X+ direction, and the second connecting plane is oriented towards the X- direction. Then, as shown... Figure 11 As shown, the actual plane at position D is offset to the left from the theoretical plane; combining these two factors can eliminate the influence of equipment errors. Similarly, as... Figure 12 Position B as shown and as Figure 13 Position C shown can eliminate the effects of equipment errors based on the same principle, that is: the first connecting surface and the second connecting surface can eliminate the effects of equipment errors.

[0059] On the other hand, during the processing, it is ensured that the angle formed by the second large end face 22 and the second connecting surface 23 is complementary to the angle formed by the first large end face 12 and the first connecting surface 13, such as... Figure 14 As shown: When the first segment 1 and the second segment 2 are connected, part A is connected to part D, and part B is connected to part C. Since the equipment cannot achieve zero error, the connecting surfaces of the two single segments are machined relative to each other. That is, the first connecting surface 13 is precision machined towards the X+ direction to become the product surface, and the second connecting surface 23 is precision machined towards the X- direction to become the product surface. During the two machining processes, the deflection direction of the milling head is 0° in one case and 180° in the other. Therefore, even if the machined surface is not perpendicular to the long side of the workpiece, the two connecting surfaces are parallel when the first segment 1 and the second segment 2 are connected, eliminating the influence of equipment error. The same applies to the Y and Z directions, ultimately ensuring that all connecting surfaces and end faces meet the accuracy requirements.

[0060] Because the frame body has a certain degree of flexibility, the data of the first positioning pin hole group and the first process pin hole group of the first section are used as the reference when machining the second positioning pin hole group and the second process pin hole group. This method can eliminate the error caused by workpiece deformation during the flipping process. It can ensure that after the final connection, the misalignment of the large end faces of the two finished sections does not exceed 0.02mm, and the 0.02mm feeler gauge cannot be inserted into the joint. After the assembly is completed, the small end faces and the cylinder guide rails of the frame are uniformly precision machined to ensure that the form and position tolerances of the 9 cylinder guide rails of the product are consistent.

[0061] Example 2

[0062] The difference between this embodiment and embodiment 1 is that in S1, the first reference is established by selecting the first large end face (Z-direction reference), the first connecting surface (X-direction reference), and the center of the bolt hole on the first large end face (Y-direction reference). In S3, the second reference is established by selecting the second large end face (Z-direction reference), the second connecting surface (X-direction reference), and the center of the bolt hole on the second large end face (Y-direction reference). The same assembly accuracy can be achieved, but the operation process is more complicated.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for assembling a segmented engine frame, characterized in that, Includes the following steps: S1. Roughly machine the surface of the first small end of the first section of the segmented engine frame, flip it so that the first large end face is facing up, and then finely machine the first large end face and the first connecting face, and machine the first positioning pin hole group and the first process pin hole group on the first connecting face. S2. Flip the first segment so that the first small end face is facing upwards, establish a first reference using the positional dimensions including the first large end face and the first connecting surface, and measure the positional dimensions of the first positioning pin hole group and the first process pin hole group. S3. Roughly machine the surface of the second small end of the second segment of the segmented engine frame, flip it so that the second large end face is facing upwards, and then finish machine the second large end face and the second connecting face. The second connecting face and the first connecting face are oriented oppositely on the machining equipment. In S3, the side position of the second large end face is machined as the second process reference surface, so that the second process reference surface, the second large end face and the second connecting face are perpendicular to each other. The relative position of the second process reference surface and the second large end face is symmetrical to the relative position of the first large end face and the first process reference surface, so that the second process reference surface and the first process reference surface are in opposite positions after the frame is closed. S4. Flip the second segment so that the second small end face is facing upwards. Establish a second reference based on the positional dimensions including the second large end face and the second connecting surface. Based on the positional dimensions of the first positioning pin hole group and the first process pin hole group measured in S2, process the second positioning pin hole group and the second process pin hole group of the second segment. In S4, the second positioning pin hole group includes multiple second positioning pin holes; the second process pin hole group includes multiple second process pin holes. In S4, the positions of the second positioning pin hole group and the second process pin hole group relative to the second reference are symmetrical with respect to the positions of the first positioning pin hole group and the first process pin hole group relative to the first reference, so that after closing, the positions of the second positioning pin hole group and the first positioning pin hole group are opposite to each other, and the positions of the second process pin hole group and the first process pin hole group are opposite to each other. S5. Connect the first connecting surface and the second connecting surface with process pins, and use multiple process pins to connect the first process pin hole group and the second process pin hole group, with the process pins respectively having an interference fit with the first process pin hole and the second process pin hole.

2. The method for assembling a segmented engine frame as described in claim 1, characterized in that, In S1, the first locating pin hole group includes multiple first locating pin holes; the first process pin hole group includes multiple first process pin holes.

3. The method for assembling a segmented engine frame as described in claim 1, characterized in that, In S1, the side position of the first large end face is the first process reference surface, so that the first process reference surface, the first large end face and the first connecting surface are perpendicular to each other.

4. The method for assembling a segmented engine frame as described in claim 3, characterized in that, In S2, a first reference is established using the first large end face, the first connecting face, and the first process reference face.

5. The method for assembling a segmented engine frame as described in claim 1, characterized in that, In S4, a second reference is established using the second large end face, the second connecting face, and the second process reference face.

6. The method for assembling a segmented engine frame as described in claim 1, characterized in that, The steps include: S6, using bolts to connect the first segment and the second segment, and reducing the gap between the first connecting surface and the second connecting surface by tightening the bolts, so that the gap is smaller than the set size.

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