The replacement of lubricating oil for the gearbox of urban rail transit vehicles mainly involves the following reasonsThere are two types of oil change: faulty oil change and regular oil change. Faulty oil change is mainly based on the condition of the gearThe properties of the wheel oil, including obvious stratification, blackening, reddening, yellowing, and whiteningWait for abnormal phenomena, and determine whether oil replacement is needed. Quantitative analysis is not required.Use the physical and chemical performance indicators, wear element content, additive element content, and pollutant element content of gearbox lubricating oil. Change the oil regularlyGenerally refer to the oil change cycle recommended by the equipment manufacturer or application experienceRecommended oil change intervals.Due to the long service life of the gearbox lubricating oil used in urban rail transit,The operating environment, operating conditions, lubrication method, brand, and type of transportation vehiclesTherefore, it is not appropriate to directly use the gearbox manufacturer’s recommendationThe recommended oil change cycle. By regularly monitoring the lubricating oil in the in-service gearbox,Operating status, comprehensive analysis of the physical and chemical performance indicators of the lubricating oil used in the gearbox, additive consumption, contaminant content, and gear systemThe wear condition and lubrication state of the gear system, which ensures the lubrication of the gearboxUnder the premise of good performance status, formulate scientific and reasonable lubricant replacementThe change of cycle can save the cost of equipment maintenance. The author makes a comparison between the urbanAnalyze the operating status of the rail transit vehicle gearbox lubricant.
The gearbox of urban rail transit vehicles is installed on the axle, which belongs toThe wheel axle is suspended and connected to the bogie frame through the derrick, mainlyIts function is to transmit driving torque during normal operation of the vehicle,The output torque and motion are transmitted to the axle through the coupling and gearbox, thusRealize the traction and braking of the vehicle.The gearbox body is mounted on the axle through two tapered roller bearingsOn the upper side, the large gear is fixed on the axle through thermal contraction, and the small gear is fixedThe fixed bearing assembly is installed in the box.The gearbox uses splash lubrication, and the lubricating oil can lubricate the teeth at the same timeBearings at both ends of the wheel and gearbox. The gear teeth are based on DIN3962-6and the DI N3963 standard adopts 18CrNiMo7-6 material for carburizing and grinding gearsmade of.
Take 75W-90 lubricating oil as an example, which is a synthetic base oilThe fully synthetic gearbox lubricant made of oil and additives. ThisThe lubricating oil meets the performance level of API GL-5, with excellent high temperature andOxidation stability, high viscosity index, low pour point and low temperatureLiquidity, which can achieve load under extreme pressure and impact load conditionsbearing capacity.At present, there is no domestic urban rail transit vehicle gearbox lubricantThere are unified technical requirements for oil change indicators, and each operating company mainly relies onOil change is carried out according to the oil change cycle recommended by the gearbox manufacturer.The manufacturer recommends changing the gear oil every year or every 150,000 kilometers,Based on field experience, the maintenance plan shall be determined according to the maintenance instructions of the gearbox manufacturer.It is recommended that the appearance color of the lubricating oil in the gearbox that is replaced should be yellowish-brown, withoutLayered, no obvious impurities at the bottom, visual judgment of the lubricant replacement cycle isThere is a certain degree of extensibility.
Select an online operating urban rail transit vehicle to carry out in-service tooth testingResearch on wheelbox lubricant tracking to maintain theContinuity and timeliness, focusing on the lubrication of urban rail transit vehicle gearboxOil operations: 115,000 kilometers as the starting mileage for follow-up research, and subsequentTake samples every 15,000-30,000 kilometers, and take samples in the early stage of 30,000 kilometersOnce, sampling is conducted at a distance of 20,000 km in the middle stage and 15,000 km in the later stageOnce, and do not change the oil within the original gearbox lubricant change cycleProcessing. Six gearbox lubricants are sampled at a time, and the gearbox numbers are divided intoDon’t sample A, B, C, D, E, F, four of which are fixed samplingpoints, numbered A, B, C, D, two gearboxes are random sampling points, numberedThe numbers are E and F. To ensure that the extracted in-use gear oil can truly reflectUnder the condition of hot gearbox lubricating oil, that is, 30 minutes after the vehicle returns to the warehouse,Within １０ minutes, use a special oil extractor to extract the middle layer from the gearbox oil fillerThe oil samples, both the bottom oil sample and the surface oil sample, are not representative, and each samplingTake about 100mL of oil sample, and if the oil level is low after sampling, add the same amount of oil.A new oil.
The evaluation method for the oil change cycle of gearbox lubricant mainly includes physical and chemical properties.can decay evaluation method, wear condition evaluation method, additive consumption evaluation methodEstimation method, pollutant assessment method, and testing items for gearbox lubricating oilMainly including physical and chemical performance indicators, wear element content, additive elementThe content of contaminants and other elements. According to GB/T30034-2013Oil change indicators for heavy-duty vehicle gear oil (GL-5), to carry out urban rail transitA study on the tracking of lubricating oil quality of gearbox in-service for road traffic vehiclesThe gearbox lubricating oil testing items include the change rate of viscosity at 100℃,Water content, acid value change, iron content, copper content, etc.
Before loading the gearbox lubricating oil, the kinematic viscosity at 100℃ is 15.6ｍｍ２／ｓ，ＧＢ／Ｔ３００３４—２０１３中要求齿轮箱润滑油 １００The change rate of viscosity at 100℃ should not exceed -15% to 10%. Therefore, the viscosity of the gearbox lubricant at 100℃ should be between 13.26 and 17.16 m2/s.The sampling points are in motion at 100℃ with the gearbox lubricating oilThe trend of viscosity change with vehicle mileage is shown in Figure 1. From the figureIt can be seen that the kinematic viscosity of the lubricating oil used in the gearbox at 100℃ isThe overall change is small with the increase of mileage, and it is always within the standard range.Within the limit value range.
The acid value of the gearbox lubricating oil before loading is 3.1mgKOH/g, GB/In T30034-2013, it is recommended that the change rate of acid value of gearbox lubricating oil should not exceed±1mgKOH/g, so the acid value of gearbox lubricating oil is recommended to beWithin the range of 2.1-4.1mgKOH/g. Each sampling point should beThe trend of the acid value of lubricating oil with the mileage of the vehicle is shown in Figure 2.As shown in Figure 2, the acid value of the lubricating oil used in the gearbox at each sampling point varies with theThe increase in mileage is not significant overall, with most of the sampled gearboxesThe acid value of the lubricating oil is within the recommended limit of the standard, and a small sample is takenThe acid value of the gearbox lubricant slightly exceeds the recommended limit.
The PQ index of the gearbox lubricant in use can be improved to a certain extent.The internal wear condition of the gearbox is reflected on the PQ index and the gearbox.The iron content and particle size in lubricating oil are linearly related, GB/TThe PQ index of gearbox lubricating oil is not limited in 30034-2013.The PQ index of the gearbox lubricating oil in use at each sampling point varies with the vehicle’s operating conditions.The trend of mileage change is shown in Figure 3. From Figure 3, it can be seen that the mileage of each pumpThe PQ index of the gearbox lubricant used at the sample point increases with the increase of mileageOverall changes are not significant, indicating that the internal gears, rolling bearings, etc. of the gearbox have not beenAbnormal wear occurs.
In-use gearbox lubricantThe limit value of iron content is not higher than 2000mg/kg. Each sampling pointThe iron element content in the lubricating oil of the in-use gearbox changes with the mileage of the vehicle.The trend is shown in Figure 4. From Figure 4, it can be seen that the average toothThe iron content in the lubricating oil of the wheel box generally increases slowly with the increase of mileage.Slowly rising trend, but the iron element content in the lubricating oil used in the gearbox is alwaysIt is far below the standard limit, indicating that the gearbox contains gears with iron elements.There is slight wear and tear in rolling bearings.
In-use gearbox lubricantThe limit value of copper content is not higher than 100mg/kg. Each sampling point isChanges in the copper content of gearbox lubricating oil with vehicle mileageThe trend is shown in Figure 5. From Figure 5, it can be seen that the gears in use at each sampling pointThe copper content in the lubricating oil of the box generally increases slowly with the increase of operating mileage.The trend is upward, but the copper content in the lubricating oil used in the gearbox is always farBelow the standard limit indicates that the gearbox contains a copper-based cageThere is slight wear due to movement of the bearing and related gaskets.
Adding extreme pressure anti-wear additives to the gearbox lubricating oil canImprove extreme pressure and anti-wear performance. Extreme pressure and anti-wear additives mainly contain phosphorus,Zinc, calcium, magnesium and other elements are usually evaluated by the content of phosphorus in the gearboxThe consumption of lubricating oil additives is not specified in GB/T 30034-2013.The phosphorus content of gearbox lubricating oil is limited. Each sampling point isThe variation trend of phosphorus content in gearbox lubricating oil with vehicle mileage. Each sampling point in the use of gearThe content of phosphorus in the lubricating oil of the box tends to increase with the increase of the mileage.The potential is not significant, indicating that there is no significant effect on the performance of the lubricant additive in the gearbox.The oxidation consumption.
The main pollution sources of urban rail transit vehicle gearboxes are moisture,Dust, etc. Usually, the moisture content and silicon content are used to evaluate gearsThe sealing performance of the gearbox. Excessive moisture content will accelerate the degradation of the gearbox lubricantOxidation, even causing oil emulsification, which in turn causes internal parts of the gearbox toCorrosion seriously affects the lubrication performance and service life of the gearbox lubricant.The solid particles such as dust intrude into the contact area of the gear or between the bearings.In the gap, it will cause abrasive wear on the friction contact surface, seriously affecting the gearThe service life of the box.The lubricating oil for gearbox in use is required in GB/T30034-2013.The water content is less than 0.5%. The gearbox used at each sampling point isThe water content in the lubricating oil is less than 0.003%, far below the standard limitThe value indicates that the sealing performance of the gearbox lubrication system is good, and there is basically nooutside moisture intrusion.The silicon element of gearbox lubricating oil is not specified in GB/T30034-2013.The content of the main components is limited. Each sampling point uses the silicon element of the gearbox lubricating oilThe trend of the content of vegetable matter with the mileage of the vehicle.The silicon element content of the lubricating oil used in the gearbox at each sampling pointThe overall change trend is small with the increase of mileage, indicating that the sealing performance of the gearbox lubrication system is good, and there is basically no external dust particlesIntrusion.
To explore the lubricating oil in the in-use gearboxUnder the condition that all physical and chemical performance indicators are normal, the acid value is slightly higher.Whether it will accelerate the corrosion of gearbox components, using copper sheet corrosion testThe method evaluates the relative degree of copper corrosion caused by gearbox lubricating oil.According to GB/T5096-2017 “Petroleum Products – Copper Strip Corrosion Test Method”It is required to immerse the copper sample in different acid value gearbox lubricantsIn the test tube, immerse the test tube into the actual operating temperature of the gearbox lubricating oil85℃, standard recommended test temperature 100℃, higher test temperature 150The copper sample was placed in an oil bath at 50℃ for 3 hours, and then the sample was taken out, washed, and dried.Then compare it with the corrosion standard color plate, and determine the discoloration of the copper sample according to theDetermine the corrosion level of the lubricating oil in the gearbox.
The results of copper strip corrosion test on the lubricating oil of the gearbox in use are shown in Table 2.From Table 2, it can be seen that at 85℃, different acid values of in-service gearbox lubricantsThe corrosion grade of oil-coated copper sheet is mild discoloration 1b; at 100℃, differentThe copper strip corrosion grade of the in-use gearbox lubricating oil with acid value is slightly discolored.1b or moderate discoloration 2b; in-service gears with different acid values at 150℃The copper strip corrosion grade of the box lubricant is moderate discoloration 2c. Test resultsIt is indicated that there is no correlation between the corrosion grade of copper sheet and the acid value of gearbox lubricating oil.In relevance.
Particles generated by the wear of gears, rolling bearings, etc. generally sink inFor the bottom oil layer, use a 100-power microscope to conduct qualitative analysisCheck. The results of the microscope inspection indicate that there is a small amount of positiveOften grinding particles, no solid metal particles, good oil cleanliness.The oil products are placed on the centrifuge with a rotation speed of 21,000 r/min for90 minutes, the solid iron particles in the oil were separated. The results showed that the separation efficiency was high.There is a small amount of sediment at the bottom of the heart tube, which is the oxidation product in the oil, but there is noSolid metal particles. Measure the iron content in the oil before and after centrifugationThe analysis shows that there is no significant change in the iron content in the oil before and after centrifugation, indicating that the iron in the oil is basically dissolved inIn the oil, rather than suspended in the oil.
Industrial endoscope can detect the gear of urban rail transit vehiclesThe surface state of the internal components of the gearbox is obtained by acquiring the toothHigh-definition images of the wheel, tooth surface, bearing, and other surfaces can comprehensively evaluate the gearWear and corrosion inside the gearbox. Large gears and small gears inside the gearboxThe surface of gears, intermediate gears, bearing cages, etc. is in good lubrication condition,The gear tooth surface does not show any abnormal phenomena such as pitting, peeling, adhesion, or cracks.The bearing cage surface also showed no signs of wear, scratching, peeling, or other abnormalities.No abnormal wear was found on the internal components of the gearbox, indicating that the gearThe lubrication system of the box is in good condition.
Through the analysis of the operating status of the lubricating oil in the gearbox of urban rail transit vehicles,Analysis of the state shows that the gearbox lubrication system is well sealed and free of external dust.Invasion of particles, moisture, etc.After using 401,000 kilometers of gearbox lubricating oil, each physical and chemicalThe performance indicators are within the standard limits, and there is no significant oxygen in the additive.consumption, and the bottom oil has good cleanliness. The gearbox lubricating oil isAfter running for 401,000 kilometers, no abnormal wear was found on the internal components of the gearbox.The gearbox lubrication system is in good condition.The acid value of the gearbox lubricating oil slightly exceeds the standard under actual operating conditions.Standard recommended limits are given, and other indicators are within the standard limits,It will aggravate the corrosion of copper-containing parts inside the gearbox, but will not cause copperThe element content has increased abnormally, but the gearbox lubricating oil can still be used.