Solution to excessive runout of diesel engine flywheel housing stopper

Abstract

The present application relates to the technical field of diesel engine, and more particularly to a method for solving the problem of flywheel housing stopper jumping out of tolerance, comprising: cover single-piece static detection: detecting whether the cover of the diesel engine with the problem of flywheel housing stopper jumping out of tolerance is deformed; tightening torque test: presetting a torque value group comprising N torque values which are not equal to each other, and each of the N torque values is greater than or equal to 150 N·m; tightening the connecting piece connecting the flywheel housing and the cover according to one torque value in the torque value group, turning the engine at least one round, measuring the flywheel housing stopper jumping amplitude, then tightening the connecting piece according to another torque value, turning the engine at least one round, measuring the flywheel housing stopper jumping amplitude, and so on, to obtain the flywheel housing stopper jumping amplitude under the tightening state of the N torque values; judgment and adjustment stage: if the cover is deformed, and the greater the torque value, the greater the flywheel housing stopper jumping amplitude, then the tightening torque of the connecting piece is reduced until the flywheel housing stopper jumping amplitude meets the requirements.

Description

Technical Field

[0001] This invention relates to the field of diesel engine technology, and in particular to a solution to the problem of excessive runout of the flywheel housing stop in a diesel engine. Background Technology

[0002] The problem of excessive flywheel housing locating runout in diesel engines refers to a runout exceeding the technical requirement of 0.5mm. This excessive flywheel housing locating runout can affect the overall vehicle assembly, especially in the field of generator assembly. When the flywheel housing locating runout is excessive, it can cause wear between the generator rotor and housing, leading to abnormal quality incidents such as generator failure. Current technology lacks suitable troubleshooting and solutions. Summary of the Invention

[0003] The purpose of this invention is to provide a solution to the problem of excessive runout of the flywheel housing stop in diesel engines, which can help identify the cause of the problem and alleviate the problem of excessive runout of the flywheel housing stop in diesel engines.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A solution to the problem of excessive runout of the flywheel housing stop surface in a diesel engine is provided. The diesel engine includes a detachably connected flywheel housing and a cover. The solution to the problem of excessive runout of the flywheel housing stop surface in a diesel engine includes the following steps:

[0006] Static inspection of the cover: The cover of the diesel engine with the problem of excessive runout of the flywheel housing stop is removed and the cover is inspected for deformation;

[0007] Tightening torque test: A preset torque value group includes N unequal torque values, all of which are greater than or equal to 150 N·m. Tighten the connector between the flywheel housing and the cover according to one of the torque values ​​in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Then tighten the connector according to another torque value in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Repeat this process to obtain the runout of the flywheel housing stop under the tightened state of N torque values.

[0008] Judgment and adjustment stage: If the cover is deformed in the static test of the cover piece, and in the tightening torque test, the larger the torque value, the greater the runout of the flywheel housing stop, reduce the tightening torque of the connector until the runout of the flywheel housing stop meets the technical requirements.

[0009] Optionally, the following steps are also included:

[0010] Single-piece static inspection of flywheel housing: Inspect whether the unassembled flywheel housing is deformed. Remove the flywheel housing with excessive runout from the diesel engine and inspect whether the assembled flywheel housing is deformed.

[0011] Optionally, in the step of static testing of a single flywheel housing, the flywheel housing is judged to be deformed by detecting whether the roundness of the stop, the position of the stop, and the position of the locating pin hole of the flywheel housing meet the dimensional requirements.

[0012] Optionally, the step of static testing of a single cover piece further includes: detecting whether the unassembled cover is deformed.

[0013] Optionally, in the step of static testing of the cover piece, the deformation of the cover is determined by detecting whether the position of the positioning pin hole of the cover meets the dimensional requirements.

[0014] Optionally, the following steps are also included:

[0015] Comparison test before and after hot test: Take the diesel engine after assembly but before hot test and rotate it at least once to measure the runout of the flywheel housing stop. Take the diesel engine after hot test and rotate it at least once to measure the runout of the flywheel housing stop.

[0016] Optionally, the following steps are also included:

[0017] Comparison test before and after packaging: Take the assembled but unpackaged diesel engine and rotate it at least once to measure the runout of the flywheel housing stop. Take the packaged diesel engine and rotate it at least once to measure the runout of the flywheel housing stop.

[0018] Optionally, the following steps are also included:

[0019] Simulation verification: Simulate the force distribution and roundness changes of the flywheel housing and the cover under different tightening torques to verify whether the excessive runout of the flywheel housing stop is related to the tightening torque of the connecting parts.

[0020] Optionally, the following steps are also included:

[0021] Risk assessment and monitoring phase: When the flywheel housing stop runout amplitude is within the preset runout amplitude, the maximum value of the corresponding tightening torque is the target torque. After the connecting parts are tightened to the target torque, it is tested whether the diesel engine has a problem with the connecting parts coming loose.

[0022] Optionally, the magnetic base of the dial indicator's support is attached to the flywheel housing, and the indicator needle contacts the wall surface of the stop of the flywheel housing to measure the runout amplitude of the stop of the flywheel housing.

[0023] The beneficial effects of this invention are:

[0024] This invention provides a solution to the problem of excessive runout of the flywheel housing stop surface in a diesel engine. The diesel engine includes a detachably connected flywheel housing and a cover. The solution to the problem of excessive runout of the flywheel housing stop surface in a diesel engine includes the following steps: Static inspection of the cover: The cover of the diesel engine with the problem of excessive flywheel housing stop surface runout is removed, and the deformation of the cover is checked; Tightening torque test: A preset torque value group includes N unequal torque values, all of which are greater than or equal to 150 N·m. The flywheel housing is tightened according to one of the torque value groups. For the connector to the cover, rotate the machine at least once and measure the runout of the flywheel housing stop. Then, tighten the connector according to another torque value in the torque value group, rotate the machine at least once, and measure the runout of the flywheel housing stop again. Repeat this process to obtain the runout of the flywheel housing stop under N torque values. During the adjustment phase: if the cover is deformed during the static inspection of a single part, and the larger the torque value in the tightening torque test, the greater the runout of the flywheel housing stop, reduce the tightening torque of the connector until the runout value of the flywheel housing stop meets the technical requirements. Static inspection of a single part of the cover can reveal whether the cover is deformed. If the cover is deformed, it indicates that the force on the cover is uneven after tightening with the flywheel housing, or that the force on a localized area of ​​the cover is too large. Deformation of the cover may cause the flywheel housing to run out of space. Further dynamic testing revealed that the greater the torque of the connector, the greater the runout of the flywheel housing stop. This suggests that a higher torque on the connector leads to more uneven stress on the cover, resulting in more significant deformation and increased flywheel housing stop runout. Therefore, reducing the tightening torque of the connector until the flywheel housing stop runout meets technical requirements can at least partially alleviate the problem of excessive flywheel housing stop runout in diesel engines. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the flywheel housing of a diesel engine;

[0026] Figure 2 This is a schematic diagram of the diesel engine cover.

[0027] Figure 3 This is a test data diagram showing the tightening torque test results for the solution to the problem of excessive runout of the diesel engine flywheel housing stop provided in the embodiment of the present invention.

[0028] Figure 4 This is a test data display diagram showing the judgment and adjustment stage of the solution to the problem of excessive runout of the diesel engine flywheel housing stop provided in the embodiment of the present invention.

[0029] In the picture:

[0030] 100. Flywheel housing; 101. First locating pin hole; 102. Second locating pin hole; 103. First bolt hole; 104. Zero point position;

[0031] 200, Cover; 201, Third locating pin hole; 202, Fourth locating pin hole; 203, Second bolt hole. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not all of them.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0035] The problem of excessive flywheel housing locating runout in diesel engines refers to a runout exceeding the technical requirement of 0.5mm. This excessive flywheel housing locating runout can affect the overall vehicle assembly, especially in the field of generator assembly. When the flywheel housing locating runout is excessive, it can cause wear between the generator rotor and housing, leading to abnormal quality incidents such as generator failure. Current technology lacks suitable troubleshooting and solutions.

[0036] Therefore, this embodiment provides a solution to the problem of excessive runout of the flywheel housing stop of a diesel engine, identifies the cause of the problem, and alleviates the situation of excessive runout of the flywheel housing stop of a diesel engine.

[0037] like Figures 1-2As shown, the diesel engine includes a detachably connected flywheel housing 100 and a cover 200, wherein the flywheel housing 100 and the cover 200 are detachably connected by multiple connectors. Optionally, in this embodiment, the flywheel housing 100 has six first through holes, namely a first locating pin hole 101, a second locating pin hole 102, and four other first bolt holes 103, wherein the first locating pin holes 101 and 102 are used for positioning during the assembly of the flywheel housing 100. The cover 200 has six second through holes, namely a third locating pin hole 201, a fourth locating pin hole 202, and four other second bolt holes 203, wherein the third locating pin holes 201 and 202 are used for positioning during the assembly. The first locating pin holes 101 correspond to the third locating pin holes 201, the second locating pin holes 102 correspond to the fourth locating pin holes 202, and the four first bolt holes 103 correspond one-to-one with the four second bolt holes 203.

[0038] Optionally, four M16 bolts are located at four sets of bolt holes to ensure a secure connection between the flywheel housing 100 and the cover 200. Two M12 bolts are located at two sets of locating pin holes to position the components during assembly and also provide a certain degree of fastening.

[0039] Optionally, the gear chamber cover 200 is located between the flywheel housing 100 and the cylinder block of the diesel engine, and is made of die-cast aluminum alloy. Its function is to seal the oil chamber where the crankshaft and camshaft gears are located.

[0040] The solution to the problem of excessive runout of the diesel engine flywheel housing stop surface includes troubleshooting and debugging, specifically including the following steps:

[0041] Static inspection of the flywheel housing cover: The flywheel housing cover 200 of the diesel engine with excessive flywheel housing stop runout is disassembled and inspected for deformation. Deformation of the flywheel housing cover 200 will cause flywheel housing stop runout, requiring further investigation into the stage and cause of the deformation. If the flywheel housing cover 200 is deformed, the deformation may have occurred during the manufacturing process or after assembly.

[0042] Therefore, optionally, the static inspection step of the cover piece may also include: detecting whether the unassembled cover 200 is deformed. If the unassembled cover 200 is deformed, it indicates that the cover 200 has already deformed during the processing. The deformation may be aggravated or offset during the assembly process. It is necessary to compare the deformation of the unassembled cover 200 and the assembled cover 200. If the difference between the two is not significant, it indicates that the deformation of the cover 200 occurred during the processing stage. If the difference between the two is significant, it indicates that the cover 200 deformed both during the processing and after assembly. If the unassembled cover 200 is not deformed, but the assembled cover 200 is deformed, it indicates that the deformation of the cover 200 occurred after assembly, and it is necessary to further investigate the assembly process to find the cause of the deformation.

[0043] Optionally, in the static inspection step of the cover unit, whether inspecting whether the unassembled cover 200 is deformed or the assembled cover 200 is deformed, the determination of whether the cover 200 is deformed is made by checking whether the position of the locating pin holes of the cover 200 meets the dimensional requirements. That is, by measuring the position of the third locating pin hole 201 and the fourth locating pin hole 202 mentioned above.

[0044] Alternatively, a coordinate measuring machine can be used for measurement to ensure measurement accuracy.

[0045] Table 1 below shows the position measurement results of the third locating pin hole 201 and the fourth locating pin hole 202 of the unassembled cover 200, and Table 2 below shows the position measurement results of the third locating pin hole 201 and the fourth locating pin hole 202 of the assembled cover 200.

[0046] Table 1

[0047]

[0048]

[0049] Table 2

[0050]

[0051] It can be seen that the positional accuracy of the unassembled cover 200 meets the technical requirements, while the positional accuracy of the assembled cover 200 does not meet the technical requirements. This means that the cover 200 was deformed during the assembly process, and the positional deviation of the two locating pin holes is nearly 0.3mm, with the overall offset trend towards the top surface of the engine.

[0052] The deformation of cover 200 during assembly is likely related to excessive tightening torque of the connecting parts. The following dynamic tightening torque test will be used to understand whether changes in tightening torque directly affect the severity of flywheel housing stop runout.

[0053] Tightening torque test: The preset torque value group includes N unequal torque values, all of which are greater than or equal to 150 N·m. Tighten the connector between the flywheel housing 100 and the cover 200 according to one torque value in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Then tighten the connector according to another torque value in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Continue in this way to obtain the runout of the flywheel housing stop under the tightened state of N torque values.

[0054] Optionally, in this embodiment, the four M16 bolts and the two M12 bolts are tightened with a torque of 99±10 N·m. The tightening order is as follows: first tighten the four M16 bolts, then tighten the two M12 bolts. Also, one of the four M16 bolts can be tightened first, then the other one on the opposite side, in order to ensure that the cover 200 is subjected to balanced force during the assembly process as much as possible.

[0055] Then, increase the tightening torque of the four M16 bolts to 150 N·m, tightening one bolt at a time, then the one on the opposite side, to ensure even force distribution on the cover 200 during assembly. Next, rotate the machine at least once to measure the runout of the flywheel housing stop.

[0056] Then, increase the tightening torque of the four M16 bolts to 200 N·m, tightening one bolt at a time, then the one on the opposite side, to ensure even force distribution on the cover 200 during assembly. Next, rotate the machine at least once a week and measure the runout of the flywheel housing stop.

[0057] Then increase the tightening torque of the four M16 bolts to 243 N·m, tightening one bolt at a time, then the one on the opposite side, to ensure even force distribution on the cover 200 during assembly. Next, rotate the machine at least once and measure the runout of the flywheel housing stop.

[0058] Optionally, in this embodiment, a dial indicator is used to measure the runout amplitude of the flywheel housing stop. Specifically, the magnetic base of the dial indicator is attached to the flywheel housing 100, and the indicator needle contacts the wall surface of the stop of the flywheel housing 100 to measure the runout amplitude of the flywheel housing stop.

[0059] Figure 1 The image shows the zero point position 104 of the flywheel housing 100, with the six o'clock position as the zero point position 104.

[0060] Table 3 below shows the runout at different points on the flywheel housing stop when the tightening torques of the four M16 bolts are 150 N·m, 200 N·m, and 243 N·m, respectively. It should be noted that the runout values ​​in the table are converted to millimeters after multiplying by 100.

[0061] Figure 3 The runout values ​​of three sets of examples are shown. It can be seen that the eleven o'clock position is the position with the largest runout of the flywheel housing stop, and it worsens as the tightening torque of the bolt increases. After the tightening torque is increased from 200N to 243N, the runout value at the eleven o'clock position increases from 0.37mm to 0.47mm.

[0062] Table 3

[0063]

[0064] To further investigate whether the flywheel housing 100 has deformed due to excessive tightening torque of the connecting parts, thus exacerbating the excessive runout of the flywheel housing stop, the solution to this diesel engine flywheel housing stop runout problem may optionally include the following steps:

[0065] Single-piece static inspection of flywheel housing: Check whether the unassembled flywheel housing 100 is deformed. Remove the flywheel housing 100 with the problem of excessive runout of the flywheel housing stop from the diesel engine and check whether the assembled flywheel housing 100 is deformed.

[0066] If the unassembled flywheel housing 100 is deformed, it indicates that the flywheel housing 100 has already deformed during the manufacturing process. The deformation may be exacerbated or offset during assembly. It is necessary to compare the deformation of the unassembled flywheel housing 100 with that of the assembled flywheel housing 100. If the difference is small, it means the deformation of the flywheel housing 100 occurred during the manufacturing stage. If the difference is large, it means the flywheel housing 100 deformed both during manufacturing and after assembly. If the unassembled flywheel housing 100 is not deformed, but the assembled flywheel housing 100 is deformed, it means the deformation of the flywheel housing 100 occurred after assembly, which is likely related to the assembly stress of the connecting parts.

[0067] Optionally, in the static inspection step of the flywheel housing, whether inspecting for deformation of the unassembled flywheel housing 100 or the assembled flywheel housing 100, the determination of whether the flywheel housing 100 is deformed is made by checking whether the roundness of the stop, the position of the stop, and the position of the locating pin holes of the flywheel housing 100 meet the dimensional requirements. Optionally, the aforementioned locating pin holes refer to the first locating pin hole 101 and the second locating pin hole 102 of the flywheel housing 100.

[0068] Optionally, a coordinate measuring machine (CMM) can be used for measurement to ensure accuracy. Table 4 below shows the measurement results of the unassembled flywheel housing 100 and the assembled flywheel housing 100. All values ​​in Table 4 are in millimeters.

[0069] Table 4

[0070] Size Name Size requirements Measured values Measured values Roundness of the stop 0.06 0.052 0.06 Stop position tolerance 0.08 0.073 0.075 Second locating pin hole position 0.08 0.05 0.053 First locating pin hole position benchmark 0 0

[0071] The technical requirements of the flywheel housing 100 design drawings stipulate that the roundness of the stop surface of the flywheel housing 100 must be less than 0.06 mm under a surface pressure of 50,000 N. During the coordinate measuring machine (CMM) measurement, all four M16 bolts and two M12 bolts were tightened to a torque of 100 N·m, which, according to design verification, is equivalent to a surface pressure of 50,000 N. Tightening measurements were performed according to the actual assembly torque of the diesel engine. Even when the tightening torque of the two M12 bolts was 100 N·m and the tightening torque of the four M16 bolts was 240 N·m, the roundness of the stop surface of the flywheel housing 100 still met the requirements. This indicates that the flywheel housing 100 did not deform during processing and assembly. The increased tightening torque did not cause deformation of the flywheel housing 100. The excessive runout of the flywheel housing stop surface is unrelated to the flywheel housing 100 itself, but is mainly related to the deformation of the cover 200 under higher torque.

[0072] Because diesel engines generate significant vibrations during bench hot testing, it is necessary to further investigate whether the hot testing process affects the excessive runout of the flywheel housing stop. Therefore, optionally, the solution to this problem of excessive flywheel housing runout in diesel engines may also include the following steps:

[0073] Comparative tests before and after hot testing: Take a diesel engine that has not been hot tested after assembly and rotate it for at least one week to measure the runout of the flywheel housing stop. Take a diesel engine that has been hot tested and rotate it for at least one week to measure the runout of the flywheel housing stop.

[0074] Table 5 below shows the runout amplitude at different points on the flywheel housing stop of a diesel engine after assembly and before hot testing, with the engine rotated at least once each. The zero point is still set at the six o'clock position (104). It should be noted that the runout values ​​in the table are converted to millimeters after multiplying by 100.

[0075] Table 5

[0076]

[0077] The comparison of the test data in Table 5 shows that the hot testing process had a certain impact on the runout of the flywheel housing stop, with an overall deviation of 0.16 mm and a deviation of 0.17 mm at some individual locations. This is because during the hot testing process, the press-fit support legs directly rested on the flywheel housing 100, while during the assembly process, the flywheel housing 100 rested on a pallet supported by the diesel engine cylinder block. This difference in the state of the flywheel housing 100 led to deviations in the measured runout data; therefore, the measurement data when the flywheel housing 100 was in a non-stressed state should be considered accurate.

[0078] To investigate whether the packaging process might exacerbate the flywheel housing stop runout problem, the solution to this diesel engine flywheel housing stop runout deviation problem may optionally include the following steps:

[0079] Comparison test before and after packaging: Take the assembled but unpackaged diesel engine and rotate it for at least one week to measure the runout of the flywheel housing stop. Take the packaged diesel engine and rotate it for at least one week to measure the runout of the flywheel housing stop.

[0080] Table 6 below shows the runout at different points on the flywheel housing stop after rotating the assembled, unpackaged and packaged diesel engines for at least one full rotation, with the 6 o'clock position still as the zero point of 104. It should be noted that the runout values ​​in the table multiplied by 100 are converted to millimeters.

[0081] Table 6

[0082]

[0083] Before leaving the factory, the diesel engine needs to be mounted on a wooden base and tightened with screws. Significant differences in the flatness of the suspension bracket or the wooden base can affect the runout of the flywheel housing stop. A comparison of the test data in Table 6 shows that the packaging process had a slight impact on the flywheel housing 100, with an overall deviation of 0.07mm and some individual locations exceeding the tolerance by less than 0.15mm.

[0084] To further investigate the effect of the tightening torque of the connectors on the forces acting on the flywheel housing 100 and the cover 200, and to compensate for the limited number of test repetitions mentioned above, the solution to the problem of excessive runout of the diesel engine flywheel housing stop can optionally include the following steps:

[0085] Simulation verification: Simulate the force distribution and roundness changes of flywheel housing 100 and cover 200 under different tightening torques to verify whether the flywheel housing stop runout problem is related to the tightening torque of the connecting parts.

[0086] Optionally, during software simulation calculations, the following prerequisites can be input: the cylinder block material is HT250, the gear chamber cover 200 material is AlSi9Cu3, and the flywheel housing 100 material is GG25.

[0087] Three sets of simulations were performed, corresponding to three different scenarios. In Scenario 1, the surface pressure of the four M16 bolts is 100,000 N, and the surface pressure of the two M12 bolts is 50,000 N. In Scenario 2, the surface pressure of the four M16 bolts is 75,000 N, and the surface pressure of the two M12 bolts is 50,000 N. In Scenario 3, the surface pressure of the four M16 bolts is 50,000 N, and the surface pressure of the two M12 bolts is 50,000 N.

[0088] The simulation results show that, due to the shape of the flywheel housing 100 and the cover 200, the stress at the eleven o'clock position of the cover 200 is the greatest. As the surface pressure of the connecting parts decreases, the stress distribution tends to be more balanced, and the roundness tends to be more intact. The simulation calculations analyzed the causes of the deformation of the cover 200 from the perspective of stress.

[0089] It can be seen that the excessive tightening torque of the connecting parts causes uneven stress on the cover 200. Furthermore, due to the low structural strength of the material of the cover 200, the cover 200 is prone to deformation, resulting in the problem of excessive runout of the flywheel housing stop.

[0090] Judgment and Adjustment Phase: If the cover shows a 200mm deformation during static testing of a single part, and the larger the torque value in the tightening torque test, the greater the corresponding runout of the flywheel housing stop, it can be roughly inferred that the flywheel housing stop runout problem is related to the excessive tightening torque of the connecting parts. Therefore, reduce the tightening torque of the connecting parts until the flywheel housing stop runout meets the technical requirements.

[0091] Optionally, in this embodiment, the tightening torque of the four M16 bolts is reduced to 200 N·m to alleviate the problem of excessive runout of the flywheel housing stop.

[0092] Table 7

[0093]

[0094] Table 7 above provides five sets of test data, which are the test values ​​of flywheel housing stop runout after the torque of the connection between flywheel housing 100 and cover 200 of the diesel engine is reduced to 200 N·m. Figure 4 As shown, after reducing the torque, the runout at the 11 o'clock position decreased significantly, and the overall runout value met the technical requirements. This indicates that the above judgment and adjustment scheme were effective, and the problem of excessive runout at the flywheel housing stop was resolved.

[0095] To prevent problems such as loose connections due to reduced tightening torque, the solution to the problem of excessive runout of the diesel engine flywheel housing stop also includes a risk assessment and monitoring phase.

[0096] Risk assessment and monitoring phase: When the flywheel housing stop runout is within the preset runout range, the maximum value of the corresponding tightening torque is the target torque. After the connecting parts are tightened to the target torque, it is tested whether there is a problem of loose connecting parts in the diesel engine.

[0097] Optionally, in this embodiment, the target torque is 200 N·m. The original process requires the M16 bolt to have a torque of 243 ± 24 N·m, and the minimum torque controlled by the process is 219 N·m. When the torque is reduced to 200 N·m, the torque is 91.3% of the original value. Calculations show that the reduction in torque has little impact on the residual axial force, and since this type of diesel engine is specifically designed for use with a generator, the overall vibration is small. Theoretically, there is no quality risk. Furthermore, actual verification and tracking show that no bolt loosening occurred when the torque was reduced to 200 N·m.

[0098] During the actual assembly process, process inspections can be conducted according to testing standards. An infrared gap measuring instrument is used after the flywheel housing 100 is assembled, scanning and measuring the position of the flywheel housing stop. In use, the infrared gap measuring instrument is fixed to the crankshaft flange. The sensor position adjustment rod of the infrared gap measuring instrument is adjusted so that its probe indicator point is within the range of the flywheel housing stop. The indicator point is rotated to the six o'clock position to zero, and then rotated uniformly for one revolution. The screen of the infrared gap measuring instrument will automatically display the maximum and minimum gap values ​​and the runout value. If the actual runout value is too large, the assembly actions can be adjusted appropriately, and the flywheel housing stop runout problem can be detected during the assembly stage, allowing for proactive solutions and improving production efficiency.

[0099] Static inspection of the cover 200 can reveal whether it is deformed. If the cover 200 is deformed, it indicates that the force on the cover 200 is uneven after tightening with the flywheel housing 100, or that the force on the cover 200 is too large in a localized area. Deformation of the cover 200 may cause the flywheel housing 100 to run out of control. Further dynamic testing reveals that the greater the torque of the connector, the greater the runout of the flywheel housing stop. This suggests that a higher torque on the connector leads to more uneven force on the cover 200, resulting in more significant deformation and increased runout of the flywheel housing stop. Therefore, reducing the tightening torque of the connector until the runout of the flywheel housing stop meets the technical requirements can at least partially alleviate the problem of excessive flywheel housing stop runout in diesel engines. Thus, the solution to this problem of excessive flywheel housing stop runout in diesel engines can identify the cause of the problem and alleviate the issue.

[0100] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A solution to the problem of excessive runout of the flywheel housing stop in a diesel engine, characterized in that... The diesel engine includes a detachably connected flywheel housing (100) and a cover (200). The solution to the problem of excessive runout of the flywheel housing stop surface includes the following steps: Static inspection of cover: The cover (200) of the diesel engine with the problem of excessive runout of the flywheel housing stop is removed and the cover (200) is inspected for deformation; Tightening torque test: The preset torque value group includes N unequal torque values, all of which are greater than or equal to 150 N·m. Tighten the connecting piece between the flywheel housing (100) and the cover (200) according to one of the torque values ​​in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Then tighten the connecting piece according to another torque value in the torque value group, rotate the machine at least one revolution, and measure the runout of the flywheel housing stop. Repeat this process to obtain the runout of the flywheel housing stop under the tightened state of N torque values. Judgment and adjustment stage: If the cover (200) is deformed in the static test of the cover piece, and in the tightening torque test, the larger the torque value, the larger the runout amplitude of the flywheel housing stop, reduce the tightening torque of the connector until the value of the runout amplitude of the flywheel housing stop meets the technical requirements.

2. The solution to the problem of excessive runout of the diesel engine flywheel housing stop as described in claim 1, characterized in that, It also includes the following steps: Single-piece static inspection of flywheel housing: Check whether the unassembled flywheel housing (100) is deformed. Remove the flywheel housing (100) with excessive flywheel housing stop runout from the diesel engine and check whether the assembled flywheel housing (100) is deformed.

3. The solution to the problem of excessive runout of the diesel engine flywheel housing stop as described in claim 2, characterized in that, In the step of static testing of the flywheel housing, the flywheel housing (100) is judged to be deformed by detecting whether the roundness of the stop, the position of the stop, and the position of the locating pin hole of the flywheel housing (100) meet the dimensional requirements.

4. The solution to the problem of excessive runout of the diesel engine flywheel housing stop as described in claim 1, characterized in that, The static inspection of the cover piece also includes: detecting whether the unassembled cover (200) is deformed.

5. The solution to the problem of excessive runout of the diesel engine flywheel housing stop as described in claim 4, characterized in that, In the static inspection step of the cover (200), the cover (200) is determined to be deformed by detecting whether the position of the positioning pin hole of the cover (200) meets the size requirements.

6. The solution to the problem of excessive runout of the diesel engine flywheel housing stop according to any one of claims 1-5, characterized in that, It also includes the following steps: Comparison test before and after hot test: Take the diesel engine after assembly but before hot test and rotate it at least once to measure the runout of the flywheel housing stop. Take the diesel engine after hot test and rotate it at least once to measure the runout of the flywheel housing stop.

7. The solution to the problem of excessive runout of the diesel engine flywheel housing stop according to any one of claims 1-5, characterized in that, It also includes the following steps: Comparison test before and after packaging: Take the assembled but unpackaged diesel engine and rotate it at least once to measure the runout of the flywheel housing stop. Take the packaged diesel engine and rotate it at least once to measure the runout of the flywheel housing stop.

8. The solution to the problem of excessive runout of the diesel engine flywheel housing stop according to any one of claims 1-5, characterized in that, It also includes the following steps: Simulation verification: Simulate the force distribution and roundness changes of the flywheel housing (100) and the cover (200) under different tightening torques to verify whether the flywheel housing stop runout problem is related to the tightening torque of the connecting parts.

9. The solution to the problem of excessive runout of the diesel engine flywheel housing stop according to any one of claims 1-5, characterized in that, It also includes the following steps: Risk assessment and monitoring phase: When the flywheel housing stop runout amplitude is within the preset runout amplitude, the maximum value of the corresponding tightening torque is the target torque. After the connecting parts are tightened to the target torque, it is tested whether the diesel engine has a problem with the connecting parts coming loose.

10. The solution to the problem of excessive runout of the diesel engine flywheel housing stop according to any one of claims 1-5, characterized in that, The dial indicator's support is magnetically attached to the flywheel housing (100), and the indicator needle contacts the wall surface of the stop of the flywheel housing (100) to measure the runout amplitude of the stop of the flywheel housing.

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