Method for profiling engine base oil pan of high-power low-speed diesel engine

Abstract

The invention belongs to the field of shell profiling, and particularly relates to a profiling method for an engine base oil pan of a high-power low-speed diesel engine. The method comprises the following steps: step 1, marking and positioning; 2, hoisting and positioning; thirdly, primary pressing and bending are conducted, an upper tire of the oil press is controlled to move downwards, pressurization is conducted after the lowest line of the upper tire coincides with the bending center line, and the oil pan plate is subjected to plastic deformation on the surface of the lower tire; step 4, angle calibration; and 5, sectional pressing is conducted, pressing is conducted in sequence in the direction of the bending center line, pressing and bending are conducted repeatedly till the angle is close to the specified angle of a drawing, and dynamic calibration is conducted through an angle template. And through segmented pressing and folding, dynamic calibration and precise positioning processes, the forming efficiency and precision of the ultra-long plate are remarkably improved. By moving the plates step by step and pressing and folding the plates step by step, continuous forming is achieved, the production efficiency and the machining precision are improved, an ultra-long mould does not need to be customized, and the equipment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of shell pressing, and particularly relates to a pressing method for the crankcase oil pan of a high-power low-speed diesel engine. Background Art

[0002] The function of the crankcase oil pan of a high-power low-speed diesel engine is to enclose the crankcase as the outer shell of the oil storage tank, prevent impurities from entering, collect and store the lubricating oil flowing back from each friction surface of the diesel engine, and at the same time dissipate part of the heat to prevent the lubricating oil from oxidizing. The oil pan is the lower half of the crankcase, also known as the lower crankcase. In a high-power low-speed diesel engine, the specific functions of the oil pan include: Enclosing the crankcase: As the outer shell of the oil storage tank, it seals the crankcase to provide a clean working environment for the engine and prevent impurities from entering and affecting the normal operation of the engine. Storing lubricating oil: Collect and store the lubricating oil flowing back from each friction surface of the diesel engine to ensure the reserve of engine oil to meet the lubrication requirements of the engine. Heat dissipation: Dissipate part of the heat in the lubricating oil to prevent the lubricating oil from oxidizing due to excessive temperature, maintain the performance of the lubricating oil, and thus extend the service life of the lubricating oil and the engine. Stabilizing the oil level: The inside of the oil pan is equipped with a stabilizing baffle to avoid the oil level oscillation and splashing caused by vehicle bumps, which is conducive to the precipitation of lubricating oil impurities and at the same time ensures the stable supply of lubricating oil. In addition, an oil dipstick is installed on the side of the oil pan to facilitate checking the oil quantity and let the operator know the remaining amount of engine oil; a drain plug is installed at the lowest point of the bottom to facilitate draining the old oil when changing the engine oil. The crankcase oil pan of a high-power low-speed diesel engine plays a crucial role in the operation of the engine.

[0003] Due to the long size and complex structure of the crankcase oil pan of a high-power low-speed diesel engine, there are significant deficiencies in the traditional pressing process. In the prior art, the oil pan plate usually needs to be integrally pressed at one time. However, since the length of the plate far exceeds the coverage range of the upper and lower dies of the oil press, precise bending cannot be directly completed. If forced to be pressed in segments, it is easy to cause misalignment of the bending center line due to positioning deviation, affecting the overall structural accuracy. In addition, the traditional method lacks dynamic calibration during the pressing and folding process and only relies on operating experience to adjust the angle, which is likely to cause uneven curvature or angle deviation, requiring multiple reworks, with low efficiency and high cost. Therefore, there is an urgent need for a high-precision and high-efficiency pressing method suitable for long oil pan plates to solve the problems of difficult positioning, difficult calibration, and poor consistency in the prior art. Summary of the Invention

[0004] In order to solve the problems that the existing pressing method for the crankcase oil pan of a high-power low-speed diesel engine cannot be used for high-precision and high-efficiency pressing of long oil pan plates, and there are problems such as difficult positioning, difficult calibration, and poor consistency during the pressing process, the present invention proposes a pressing method for the crankcase oil pan of a high-power low-speed diesel engine, including the following steps:

[0005] S1: Marking and positioning: Mark the oil pan sheet, and mark the bending center line and bending edge line on the surface of the oil pan sheet.

[0006] S2: Lifting and positioning: Lift the oil pan sheet to the working table of the oil press, and determine its placement position through a positioning ruler.

[0007] S3: Initial pressing and folding: Control the lower movement of the upper die of the oil press, so that the lowest line of the upper die coincides with the bending center line and then apply pressure, causing the oil pan sheet to undergo plastic deformation on the surface of the lower die.

[0008] S4: Angle calibration: Use an angle template to inspect the bending rate of the sheet after profiling.

[0009] S5: Sectional profiling: Profile successively along the direction of the bending center line, repeatedly press and fold until it is close to the angle specified in the drawing, and dynamically calibrate through the angle template.

[0010] According to a profiling method for the oil pan of a large-power low-speed diesel engine block described above, the length of the oil pan sheet exceeds the total length of the upper die and the lower die. During the profiling process, the oil pan sheet is moved in sections and steps S3 - S5 are repeated.

[0011] According to a profiling method for the oil pan of a large-power low-speed diesel engine block described above, in step S1: Use a laser marking instrument to mark the bending center line and bending edge line on the surface of the oil pan sheet, and the parallelism error between the bending center line and the bending edge line ≤ 0.2 mm; the bending center line is the theoretical center line of the bending arc after profiling the oil pan sheet, and the bending edge line is the bending boundary line on both sides of the oil pan sheet.

[0012] According to a profiling method for the oil pan of a large-power low-speed diesel engine block described above, in step S2: Lift the oil pan sheet to the working table of the oil press by a crane; use an adjustable positioning ruler to calibrate the position of the oil pan sheet, so that the bending center line is aligned with the reference line of the positioning ruler, and the positioning error is controlled within ±0.5 mm; the positioning ruler is a rigid fixture with a scale ruler and is fixed to the working table of the oil press by bolts.

[0013] According to a profiling method for the oil pan of a large-power low-speed diesel engine block described above, in step S3: Start the oil press, control the upper die to move vertically downward at a speed of 5 - 10 mm / s until the lowest line of the upper die coincides with the oil pan sheet and plastic deformation occurs on the surface of the lower die, forming an initial bending section; the surface of the lower die is provided with a V-shaped groove, and the groove depth is 1.2 times the thickness of the oil pan sheet, which is used to guide the direction of plastic deformation.

[0014] According to the above-mentioned method for pressing the crankcase oil pan of a high-power low-speed diesel engine, in step S4: Take out the pressed plate and use an angle template to detect the bending rate; the angle template is a multi-angle adjustable template, including three reference angles of 5°, 10°, and 15°. When detecting, it fits the bent surface of the pressed plate. If the deviation exceeds ±1°, readjust the position of the upper die and press and fold it twice.

[0015] According to the above-mentioned method for pressing the crankcase oil pan of a high-power low-speed diesel engine, in step S5: Move the pressed plate along the bending direction, and the moving distance each time does not exceed 80% of the effective working length of the upper die; Repeat steps S3 - S4, press and fold section by section until all bending processes are completed. The final bending angle error from the angle specified in the drawing is ≤1°; After every three sections of pressing and folding are completed, use a laser rangefinder to detect the straightness of the overall bending edge line, and the cumulative deviation is ≤1.5 mm.

[0016] According to the above-mentioned method for pressing the crankcase oil pan of a high-power low-speed diesel engine, in step S5: After pressing is completed, send the pressed plate into an annealing furnace for stress relief. The annealing temperature is 450 - 500 °C, and keep it warm for 30 minutes; Use a three-dimensional scanner to compare the finished product with the drawing data to ensure that the curvature radius error is ≤2 mm and the angle error is ≤1°.

[0017] According to the above-mentioned method for pressing the crankcase oil pan of a high-power low-speed diesel engine, the contact surface between the upper die and the lower die is provided with a wear-resistant coating, and the hardness is not less than HRC60.

[0018] According to the above-mentioned method for pressing the crankcase oil pan of a high-power low-speed diesel engine, during the pressing process, the oil pan plate needs to be locally preheated, and the preheating temperature is 150 - 200 °C.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. Through the processes of sectional press and fold, dynamic calibration, and precise positioning, the present invention significantly improves the efficiency and accuracy of the forming of ultra-long plates. By moving the plate step by step and pressing and folding it successively, continuous forming is achieved, the production efficiency is increased by more than 30%, and there is no need to customize ultra-long dies, reducing the equipment cost.

[0021] 2. The present invention uses an angle template and a laser rangefinder to calibrate each section of press and fold in real time, controls the angle error within ±1°, and the curvature radius deviation is ≤2 mm, avoiding the rework problem caused by cumulative errors, and the product qualification rate is increased to more than 98%.

[0022] 3. Through the alignment technology of the positioning ruler and the center line of the upper die, the present invention ensures that the initial positioning accuracy of the plate reaches ±0.5 mm. Combined with the sectional press and fold length not exceeding 80% of the effective area of the die, it effectively reduces the non-uniformity of material deformation, and the structural strength of the finished product is increased by 15%.

[0023] 4. The present invention eliminates internal stress through annealing treatment, further ensuring the long-term use stability of the oil pan. While ensuring high precision, this method significantly shortens the production cycle, reduces the rejection rate, is applicable to the mass production of large-sized oil pans with complex curvatures, and has significant economic benefits and industrial application value. Description of the Drawings

[0024] Figure 1 is a state diagram of the sheet metal of the oil pan of a large-power low-speed diesel engine base before profiling in a profiling method of the oil pan of a large-power low-speed diesel engine base according to the present invention.

[0025] Figure 2 is a state diagram of the sheet metal of the oil pan of a large-power low-speed diesel engine base after profiling in a profiling method of the oil pan of a large-power low-speed diesel engine base according to the present invention.

[0026] In the figure: 1 - hydraulic press, 2 - upper die, 3 - oil pan sheet metal, 4 - lower die, 5 - positioning ruler, 6 - profiled sheet metal, 7 - angle template. Detailed Embodiments

[0027] Preferred Embodiment

[0028] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0029] As Figures 1 to 2 shown: In this embodiment, a profiling method for the oil pan of a large-power low-speed diesel engine base includes the following steps:

[0030] S1: Marking and positioning. Mark the bending center line and bending edge line on the surface of the oil pan sheet metal 3 by marking the oil pan sheet metal 3.

[0031] S2: Lifting and positioning. Lift the oil pan sheet metal 3 to the workbench of the hydraulic press 1 and determine its placement position through the positioning ruler 5.

[0032] S3: Primary folding. Control the lower movement of the upper die 2 of the hydraulic press 1 so that the lowest line of the upper die 2 coincides with the bending center line and then apply pressure to cause plastic deformation of the oil pan sheet metal 3 on the surface of the lower die 4.

[0033] S4: Angle calibration. Use the angle template 7 to check the bending rate of the profiled sheet metal 6.

[0034] S5: Sectional profiling: Profile sequentially along the bending center line direction, repeatedly fold until close to the angle specified in the drawing, and dynamically calibrate through the angle template 7.

[0035] The length of the oil pan sheet 3 exceeds the total length of the upper die 2 and the lower die 4. During the profiling process, the oil pan sheet 3 is moved in segments and steps S3 - S5 are repeated.

[0036] Use a laser scribing instrument to mark the bending center line and the bending edge line on the surface of the oil pan sheet 3. The parallelism error between the bending center line and the bending edge line is ≤ 0.2 mm; the bending center line is the theoretical center line of the curved arc after profiling the oil pan sheet 3, and the bending edge line is the bending boundary line on both sides of the oil pan sheet 3.

[0037] Lift the oil pan sheet 3 to the workbench of the oil press 1 by a crane; use an adjustable positioning ruler 5 to calibrate the position of the oil pan sheet 3 so that the bending center line is aligned with the reference line of the positioning ruler 5, and the positioning error is controlled within ±0.5 mm; the positioning ruler 5 is a rigid fixture with a scale ruler and is fixed to the workbench of the oil press 1 by bolts.

[0038] Start the oil press 1, control the upper die 2 to move vertically downward at a speed of 5 - 10 mm / s until the lowest line of the upper die 2 completely coincides with the bending center line of the oil pan sheet 3; apply a pressing pressure of 80 - 120 MPa and hold the pressure for 3 - 5 seconds to cause plastic deformation of the oil pan sheet 3 on the surface of the lower die 4 to form an initial bending section; the surface of the lower die 4 is provided with a V-shaped groove, and the groove depth is 1.2 times the thickness of the oil pan sheet 3, which is used to guide the direction of plastic deformation.

[0039] Take out the profiled sheet 6 and use an angle template 7 to detect the bending rate; the angle template 7 is a multi-angle adjustable template, including three reference angles of 5°, 10°, and 15°. When detecting, it fits the bending surface of the profiled sheet 6. If the deviation exceeds ±1°, re-adjust the position of the upper die 2 and press and fold it again.

[0040] Move the profiled sheet 6 along the bending direction, and the moving distance each time does not exceed 80% of the effective working length of the upper die 2; repeat steps S3 - S4 and press and fold section by section until all bending processes are completed. The error between the final bending angle and the angle specified in the drawing is ≤ 1°; after every three sections of pressing and folding are completed, use a laser rangefinder to detect the straightness of the overall bending edge line, and the cumulative deviation is ≤ 1.5 mm.

[0041] After profiling is completed, send the profiled sheet 6 into an annealing furnace for stress relief. The annealing temperature is 450 - 500 °C and keep it warm for 30 minutes; use a 3D scanner to compare the finished product with the drawing data to ensure that the curvature radius error is ≤ 2 mm and the angle error is ≤ 1°.

[0042] The contact surface of the upper die 2 and the lower die 4 is provided with a wear-resistant coating, and the hardness is not less than HRC60.

[0043] During the profiling process, local preheating of the oil pan sheet 3 is required, and the preheating temperature is 150 - 200 °C.

[0044] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

[0045] First: Marking and positioning

[0046] As Figure 1 shown, first, according to the requirements of the drawing, mark the bending center line and the bending edge line on the surface of the oil pan plate 3. The marking tool is a high-precision laser marking instrument to ensure that the parallelism error between the center line and the edge line is ≤ 0.2 mm.

[0047] Second: Lifting and positioning

[0048] Lift the oil pan plate 3 to the workbench of the oil press 1, adjust the positioning ruler 5 to the preset coordinates, and align the bending center line of the oil pan plate 3 with the reference line of the positioning ruler 5. The positioning error is controlled within ±0.5 mm.

[0049] Third: Initial pressing and folding

[0050] Start the oil press 1, control the upper die 2 to move down slowly until its lowest line completely coincides with the bending center line of the oil pan plate 3. Apply a pressure of 100 MPa and hold the pressure for 4 seconds to cause plastic deformation of the oil pan plate 3 on the surface of the lower die 4 to form a preliminary bending structure, as Figure 2 shown.

[0051] Then: Angle calibration

[0052] Remove the formed plate 6, and use the angle template 7 to detect the bending rate. If the angle deviation exceeds 2°, adjust the position of the upper die 2 and re-press and fold.

[0053] After that: Sectional pressing and forming

[0054] Since the oil pan plate 3 is extremely long, it is necessary to move the oil pan plate 3 along the bending direction so that the un-pressed section is aligned with the upper die 2. Repeat steps 3 - 4 to press and fold section by section, and the pressing and folding length of each section does not exceed 80% of the effective working area of the upper die 2.

[0055] Finally: Dynamic verification

[0056] After every three sections of pressing and folding are completed, use a laser rangefinder to detect the straightness of the overall bending edge line to ensure that the cumulative deviation is ≤ 1.5 mm. If it exceeds the tolerance, it is necessary to locally correct the pressing and folding parameters.

[0057] Scrap material treatment

[0058] During the pressing and folding process, the edge scrap material of the oil pan plate 3 falls into the groove of the lower die 4 to avoid affecting the pressing and forming accuracy due to material accumulation.

[0059] Annealing treatment

[0060] After all the profiling is completed, the profiled sheet 6 is sent into an annealing furnace, kept at 480 °C for 30 minutes to eliminate internal stress and improve structural stability.

[0061] Final inspection

[0062] Use a 3D scanner to compare the finished product with the drawing data to ensure that the error of all bending angles ≤ 1° and the error of the curvature radius ≤ 2 mm.

[0063] Through the above steps, the present invention realizes the high-efficiency and high-precision profiling of the ultra-long oil pan sheet, significantly improving the product quality and production efficiency.

[0064] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A method for forming an oil pan of a high-power low-speed diesel engine base, characterized in that: The following steps are involved: S1: marking and positioning, marking the oil pan plate (3), and marking the bending center line and bending edge line on the surface of the oil pan plate (3); S2: hoisting and positioning, hoisting the oil pan plate (3) to the workbench of the hydraulic press (1), and determining its placement position by means of a positioning ruler (5); S3: initial folding, controlling the upper tire (2) of the hydraulic press (1) to move downward, so that the lowest line of the upper tire (2) coincides with the bending center line, and then applying pressure to cause the oil pan plate (3) to undergo plastic deformation on the surface of the lower tire (4); S4: Angle calibration, using an angle template (7) to check the curvature of the sheet (6) after profiling; S5: Segmented profiling: Profiling is performed sequentially along the centerline of the bend, and the angle is repeatedly folded to a value close to the angle specified in the drawing, and dynamically calibrated through the angle template (7).

2. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 1, characterized in that: The length of the oil pan plate (3) exceeds the total length of the upper tire (2) and the lower tire (4). During the profiling process, the oil pan plate (3) is moved in sections and steps S3 to S5 are repeated.

3. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 2, characterized in that: In step S1: a laser marking instrument is used to mark a bending center line and a bending side line on the surface of the oil pan plate (3), wherein the parallelism error between the bending center line and the bending side line is ≤0.2 mm; the bending center line is the theoretical center line of the bending arc of the oil pan plate (3) after profiling, and the bending side lines are the bending boundary lines on both sides of the oil pan plate (3).

4. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 3, characterized in that: In step S2: the oil pan plate (3) is hoisted to the workbench of the hydraulic press (1) by a crane; the position of the oil pan plate (3) is calibrated by an adjustable positioning ruler (5) so that the bending center line is aligned with the reference line of the positioning ruler (5), and the positioning error is controlled within ±0.5 mm; the positioning ruler (5) is a rigid clamp with a scale, and is fixed to the workbench of the hydraulic press (1) by bolts.

5. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 4, characterized in that: In step S3: the hydraulic press (1) is started, and the upper tire (2) is controlled to move vertically downward at a speed of 5-10 mm / s until the lowest line of the upper tire (2) completely coincides with the bending center line of the oil pan plate (3); a pressurizing pressure of 80-120 MPa is applied, and the pressure is maintained for 3-5 seconds, so that the oil pan plate (3) undergoes plastic deformation on the surface of the lower tire (4) to form an initial bending section; the surface of the lower tire (4) is provided with a V-shaped groove, the depth of which is 1.2 times the thickness of the oil pan plate (3) for guiding the direction of plastic deformation.

6. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 5, characterized in that: In step S4: the profiled sheet (6) is taken out and the curvature is detected using an angle template (7); the angle template (7) is a multi-angle adjustable template, including three reference angles of 5°, 10° and 15°. During the detection, the curved surface of the profiled sheet (6) is fitted. If the deviation exceeds ±1°, the position of the upper tire (2) is readjusted and folded a second time.

7. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 6, characterized in that: In step S5: the profiled plate (6) is moved along the bending direction, and each moving distance does not exceed 80% of the effective working length of the upper tire (2); steps S3-S4 are repeated, and the bending process is completed section by section, and the final bending angle has an error of ≤1° with the angle specified in the drawing; after each three sections of bending are completed, a laser rangefinder is used to detect the straightness of the overall bending edge line, and the cumulative deviation is ≤1.5mm.

8. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 7, characterized in that: In step S5: after the forming is completed, the formed sheet (6) is sent to an annealing furnace for stress relief, the annealing temperature is 450-500°C, and the temperature is kept for 30 minutes; a 3D scanner is used to compare the finished product with the drawing data to ensure that the curvature radius error is ≤2mm and the angle error is ≤1°.

9. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 8, characterized in that: The contact surfaces of the upper tire (2) and the lower tire (4) are provided with a wear-resistant coating with a hardness not less than HRC60.

10. A method for forming an oil pan of a high-power low-speed diesel engine base according to claim 1 or 9, characterized in that: During the pressing process, the oil pan plate (3) needs to be partially preheated at a temperature of 150-200°C.

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