The technical transformation of CA8013 type non-falling wheel lathe Liu Shudong (Datong Railway Sub-bureau Datong West Power Machinery Section, Datong, Shanxi 037011) has carried out in-depth and meticulous analysis. Discussion, the main reason for the machine tool failure is the unreasonable design of the mechanical bearing. The hydraulic profiling system is unstable and the electrical control loop capacity is small, accounting for 93.75% of the total number of faults. The calculation test proposed the replacement of the main drive bearing. Hydraulic profiling system CNC transformation and electrical components. Specific measures such as line capacity increase. Through the transformation, the machining accuracy and production efficiency of the machine tool have been significantly improved, the failure rate has dropped by 74%, and great success has been achieved, especially the use of numerical control technology to transform the special machine tool, and the mechanical and electrical integration of the machine equipment has been changed to Liu Shudong (1964). ?) Male, Tangshan, Hebei, engineer (: 2004 made a new road.
5+3 logo code: A 1 Foreword In recent years, with the increase of the number of locomotive traction and the gradual deepening of the locomotive repair reform, the locomotive repair and overhaul kilometers have been greatly adjusted, due to the heavy-duty trains and The length of the inspection and the extension of the kilometers, the wear and tear of the wheel is getting more and more serious, and the task of locomotives to carry out the repair of the wheel is increasing year by year. According to the statistics of the Datong West Power locomotive, the number of locomotives in 1999 was 129. 406. Therefore, it is of great significance to ensure the normal operation of the existing wheel-pair maintenance equipment, improve the quality of wheel-to-spin repair, and shorten the locomotive stop-and-go time of the locomotive to ensure the completion of transportation tasks and the safety of locomotive operation.
The CA8013 non-falling wheel pair lathe is a hydraulic profiling machine designed and put into production in the early 1980s. It is mainly used to repair special equipment for the rim and tread of the 1435mm electric locomotive without disintegration wheelset. Datong West Power locomotive section was installed and put into use in 1991. At that time, it was still relatively advanced in China, especially the opening operation of the newly built Daqin Line. The Datong West Locomotive Depot was responsible for the towing task of the Datong-Liu Village heavy-duty train, along with the 8K electric locomotive. The single-machine traction test 5000t, 6000t and double-machine traction 10000t have succeeded successively, and the traction task of heavy-duty trains has gradually increased. Because the Daqin line is a new line, the wheel wear of the machine is very large. During a period of time, the CA8013 does not have a high utilization rate of the lathe, which has made a great contribution to the maintenance work of the wheel of the locomotive.
2Proposal of the problem With the increase of the service life, the failure rate of the CA8013 does not fall on the lathe is increasing year by year. In particular, the defects in the innate design are gradually revealed. According to statistics, 96 equipment failures occurred in 1999, and the equipment was shut down. The accumulated time is 62 days, and the annual maintenance cost is 190,000 yuan, which has seriously affected the completion of transportation tasks and locomotive maintenance. We have statistically classified the faults that occurred on the machine tool, as shown in Table 1.
Table 1 CA8013 non-falling wheel to lathe fault classification statistics table fault type number of pieces cumulative frequency frequency accumulative mechanical system fault hydraulic profiling fault electrical system fault other total through the above analysis, the main cause of the machine tool failure rate is mechanical system, hydraulic The failure of the profiling system and the electrical system accounted for 93.75% of the total number of faults. Therefore, for each of the above three kinds of faults, technical transformation one by one is the only way to ensure the machining accuracy, quality and task completion of the machine wheels.
3 Reason analysis 31 Mechanical system failure analysis The friction wheel rotation axis is the main drive shaft of the machine. If the spindle is turbulent and bouncing, the influence on the tool cutting, transmission force distance and hydraulic profile system is very large.
It is the right main drive system diagram of the lathe on the lathe of CA8013. The VI and X axes of the main drive of the machine are the main drive shaft of the friction wheel. The transmission principle is that the friction wheel relies on the axle load to compress the tread on the wheelset. The wheel pair is rotated by the main motor, the pulley and the gearbox to the main shaft friction wheel. The axle load of the wheel pair acts on the four friction wheels. When the friction wheel rotates, the friction torque is generated by the wheel pair to rotate the wheel pair. The magnitude of the cutting force depends on the friction torque, that is, the magnitude of the axle weight. Therefore, there must be sufficient friction torque in the friction transmission, otherwise the slip phenomenon will occur in the cutting transmission. The axle load and friction coefficient are the main factors affecting the friction torque. Because the wheelset has 10% and 20% slope respectively, the friction wheel has a corresponding inclination when it is designed for the outer type, so that inevitably generating an axial force requires axial support of the machine tool.
CA8013 does not drop the wheel to the right main drive system of the lathe. Since the front end of the original design friction wheel drive shaft VI is a double row radial spherical roller bearing of type 3003724, the rear end is a short disc with a single row of 32218 models. Cylindrical roller bearings do not have the effect of supporting axial force. Therefore, during the use process, the axial movement of the main shaft and the radial runout of the wheel often occur, which can easily cause the accident of the cutter, affect the processing quality, and even lead to the tire. Serious consequences of retirement. After the main axial direction is swayed, the rear end cover is worn. When there are two axial forces, the rear end cover of the main shaft is squeezed, and the bolt is broken, which causes the machine to stop and repair, and the machining quality and precision of the wheel pair. And the completion of the task has a great impact and needs to be improved.
3.2 Failure analysis of hydraulic profiling system The instability of the follow-up valve in hydraulic profiling and the poor electronic control quality of the electro-hydraulic proportional speed control valve cause the profiling system to be inferior, resulting in the machining accuracy and surface roughness of the wheel rim tread. Meet the technical requirements.
The original hydraulic profiled part is a hydraulic profile system consisting of a profiled contact (following valve), a template and a vertical cylinder of the tool holder and a horizontal cylinder. When the profiling is determined by the profiling template, the vertical valve and the horizontal cylinder act accordingly, so that the movement path of the tool holder and the shape of the template are consistent. By setting the electro-hydraulic proportional speed regulating valve to maintain or approximately maintain the tool holder synthetic feed amount in the process of profiling, the surface roughness of the entire wheel contour is ensured. After the long-term use of the hydraulic profiling system, the electronic control quality of the electro-hydraulic proportional speed regulating valve is not good, and the feed rate of the tool holder is not constant, so that the roughness does not meet the technical requirements. On the other hand, the follow-up valve is difficult to repair after wear, plus the profile system has many hydraulic system control links, the pressure and flow of the oil pump, the temperature and vibration of the electro-hydraulic proportional speed control valve and the follow-up valve. Will have an impact on the profiling, resulting in inaccurate profiling, or even profiling failure, resulting in the wheel rim tread processing accuracy and surface roughness does not meet the technical requirements, so the profiling system has many failures, low efficiency, and needs improvement.
3.3 Failure Analysis of Electrical System In 2000, the CNC was modified by CA8013. The main purpose is to change the hydraulic profile control mode of the original tool holder to the numerical control mode. The other parts of the machine tool are maintained as they are. The machine tool efficiency and workpiece machining accuracy after CNC transformation have been greatly improved. However, after the CNC transformation of the machine tool, some electrical control problems have occurred after a period of operation. For example, after 1.5 hours of machine operation, abnormal shutdown occurs, that is, the phenomenon of “black screenâ€, and then restart after shutdown, less than half an hour. Stop "black screen". Because the machine tool is automatic cutting, it has to be re-tooled after the machine stop, which delays the working time and shortens the service life of the wheel. Moreover, the abnormal stop is very likely to cause the knife accident, and there is a safety hazard. Usually a car It takes only 2~3h for wheelset cutting, and it can't be processed for more than ten hours when the fault occurs, which has a great impact on the processing and quality of the wheelset.
4 Improvement measures 41 Partial transformation of the main drive shaft For the CA8013 non-falling wheel to the axial drive and radial runout of the main drive shaft of the lathe, organize relevant engineering and technical personnel, maintenance personnel to carry out the work, observation and test, detailed analysis, inspection With regard to drawings and technical data, the proposed improvement measures are to replace the rear end bearing of the main shaft to support the axial force and prevent the occurrence of the spindle's turbulence and bounce.
We chose to replace the single-row radial short cylindrical roller bearing 32218 at the last end of the main shaft as a single-row radial thrust ball bearing 36218. The new and old bearing sizes and performance pairs are shown in Table 2.
Table 2 New and old bearing size, performance comparison table Bearing model inner diameter d outer diameter D width B rated dynamic load / kN rated static load / kN limit speed from Table 2 shows that the new bearing 36218 in addition to the rated dynamic and static load index is slightly lower, other dimensions And the limit speed fully meets the requirements of the replaced bearing 32218.
The rear end cover of the single row radial thrust ball bearing 36218 is pressed by the bolt to press the bearing outer casing, and the inner sleeve of the main shaft is pressed against the rear step of the main shaft to play the axial support.
The requirements of the special strict liquid J system instability will inevitably cause the profiling fault gHus to completely replace the hydraulic imitation of the original machine tool liquid 42 hydraulic profiling system, the compression of the profiling part of the electro-hydraulic proportional speed control valve, follow-up valve, The template, horizontal and vertical cylinders are all canceled, the internal structure of the original slide is modified, and the AC servo motor drive unit and the gear screw drive system are installed at the position of the crude oil cylinder. The components related to the movement of the electric part and the tool holder and the left and right operation button stations are all canceled, and the two CNC button stations are replaced. The CRT and the main control of the CNC system are installed on the machine operation button station, and the servo transformer and servo unit are installed in the rearrangement. In the feed box. The whole system is divided into man-machine interface CRT, command input keyboard, CNC control system, power amplification, servo drive, X, Y axis direction feed mechanical system. The numerical control system adopts the German Siemens universal numerical control system, and the AC servo motor has an encoder, which can realize the position semi-closed loop control. Its driving characteristics are completely consistent with the driving characteristics required by the non-falling wheel to the lathe feed system, which ensures the reliable operation of the machine tool. Sex.
When the tool holder action is required, the operator only needs to press the button, the command is transmitted to the servo unit through the CNC, and the servo unit drives the servo motor to run. The encoder inside the motor monitors the motor operation data at any time and feeds the data back to the servo unit. The servo unit transmits this signal to the CNC. If the data is consistent with the data sent by the CNC, the motor will run normally. Otherwise, the protection device will be activated to stop the motor.
Both the vertical and horizontal slides of the tool holder are cast steel parts, and the vertical and horizontal guide rails are all plated steel guide rails with high precision, good wear resistance and long service life. The ball screw support adopts the thrust angular contact bearing. The feed transmission chain adopts no gap connection, and the reverse dead space dead zone is small. In addition, the numerical control system has the gap compensation function, which makes the tool holder have high positioning precision and high machining precision.
43Electrical control circuit modification CA8013 does not fall off the wheel to the lathe after the NC transformation, often occurs, as the control circuit electrical schematic diagram, during the inspection process, the control circuit heat is found in the KAi, KA2, KA3 intermediate relay normally open contact burn Loss, the control line is hot. After replacing the intermediate relay of the same model, the fault occurs again after running for a while. Through testing and analysis, it is confirmed that the contact capacity of the intermediate relay is not enough, causing the power unit to protect itself and not controlling the power output.
After research, it was decided to replace the original intermediate relay with CJio AC contactor, and replace the main contactor with the contactor of CJi?ZB type 40A to prevent the contact of the main contactor from sticking to death. At the same time, some control lines were expanded and modified. From the original 1.5mm2 to 2.5mm2. 5 achieved the effect of the CA8013 non-falling wheel on the lathe mechanical system, hydraulic profiling system and electrical control circuit and other aspects of the transformation, in 2001, after nearly one During the operation of the year, the machine tool improves the machining accuracy, ensures the quality of the wheelset, reduces the fault, and improves the production efficiency. The principle of controlling the electrical circuit of the machine 51 improves the machining accuracy and ensures that the wheelset quality CNC transformation uses less mechanical transmission chain, and By increasing the system stiffness and reducing the gap, the errors caused by the mechanical wear and the gap and the force deformation are greatly reduced. At the same time, the automatic detection and computer control compensation are used to correct the dynamic error caused by various factors, and the accuracy is improved. After the transformation, the curve error is 0.5mm, the rolling circle beat is less than 1.0nm, the surface roughness Ra is not more than 125m, the processing tread completely meets the technical requirements, and has the characteristics of less processing and rework.
5.2 Reduce the failure, improve the production efficiency of the station, 543 pairs of wheels, equipment utilization rate reached 78%, the equipment failure rate decreased significantly. In 1999 and 2001, the machine faults were as shown in Table 3. In 1999, there were 96 equipment failures, and in 2001, 25 faults occurred, down 74% year-on-year, and the stability and reliability of the machine tools were great. Improvement, and the working time is shortened from 45min/per knife to 26min/per knife (excluding auxiliary time) before the transformation, which greatly shortens the stop time of the locomotive and the extended working time of the locomotive wheel due to machine failure, and the production efficiency is improved. 42%, and through the transformation to solve the original failure point, compared to the same year, the annual maintenance cost of the table 3 1999 and 2001 machine failure comparison table electrical control failure other average decline 5.3 improved operability after the NC transformation, each The action sequence and function coordination relationship of the relevant transmission mechanism can be automatically realized by program control, and a good human-machine interface is established through the CRT to prompt the operation, so that complicated function control and use effects can be obtained through simple operation.
54 Eliminated the "black screen" failure through the CA8013 non-falling wheel to the CNC lathe control loop capacity transformation, the machine has been running so far, no "black screen" failure, completely eliminate the occurrence of similar faults, to ensure the normal use of CNC machine tools.
6Technical innovation and promotion suggestions After the original CA8013 does not reduce the mechanical, electrical and numerical control of the lathe, the machining accuracy and production efficiency are significantly improved, the technical content is high, and great success has been achieved, especially the use of communication standards. The success of the CNC system on the numerical control transformation of the machine tool has explored a new way for the transformation of the mechanical and electrical integration of the machine equipment. Due to the improved machining accuracy and surface quality of the wheelset, the performance of the locomotive running section is improved, which lays a good foundation for the locomotive speed increase and heavy load, improves the productivity, reduces the locomotive maintenance time, ensures the supply of locomotives, and satisfies the railway expansion. The need for transportation to the locomotive.
(Continued from page 6) 10 Experience the era of extensive application of virtual prototyping technology in the design and development of products at home and abroad, widely used CAx technology for virtual design development and simulation analysis of products, so that before the physical prototype production of the product, Various important information about the product can be obtained in advance, and the product can be evaluated based on the information. In order to fundamentally guarantee the quality of the product and obtain a good variety of performance, reduce the error generated in the development process into the production process, gradually reduce the number of trials and tests of the physical prototype, shorten the development cycle, and thus reduce costs.
In the problems discussed in this paper, the application of CAD and CAE technology to the three-dimensional design, simulation calculation analysis, test verification and other modern design methods of 300km/h high-speed bogie make the research and development of this product reliable, from manufacturing to testing. Once successful, we can see the good application prospects of virtual design technology.
(Finish)
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