Ningbo Hardchn bearing Co., Ltd.
1) Improve the quality of bearing manufacturing and ove […]
1) Improve the quality of bearing manufacturing and overhaul. In particular, manufacturers and overhaul manufacturers should focus on controlling the outer ring groove depth, width, processing roundness and outer ring processing chamfering geometric dimensions, which do not meet the requirements of the drawings and are prohibited from leaving the factory.
2) Establish an information communication system between bearing manufacturers and overhaul manufacturers and users. Organize quality exchanges between manufacturers and users every year. The user feedbacks the bearing manufacturing quality problems to the bearing manufacturers and overhaul manufacturers, so as to cause the manufacturers and overhaul manufacturers to pay attention to the quality of bearing processing, and avoid the same quality problems in the bearings manufactured in the future. During the bearing overhaul, the bearing overhaul factory processes the bearings whose processing quality does not meet the standard to meet the process standards. The accessories that cannot meet the standard should be scrapped and must not be assembled into the overhauled bearing.
3) For bearings with manufacturing quality problems found during general maintenance and within the warranty period, the manufacturer will claim compensation and return the bearings to the manufacturer for analysis. The manufacturer will formulate targeted rectification measures for the problems to better improve The quality of the source of the bearing reduces the occurrence of hot shaft accidents caused by bearing failure during operation.
4) Strengthen the control measures for the appearance inspection and component inspection of the sealing cover during section repair.
a. Special appearance inspection procedures are set up at the two places of bearing income and bearing closure. For non-removable bearings, workers, foremen, quality inspectors, and inspectors are rotated one by one.
b. During visual inspection, the outer ring of the bearing must be manually rotated for more than 3 to 5 turns, and the external state and internal abnormal noise must be carefully checked. For bearings without abnormal noise, the outer ring of the bearing and the sealing cover (outer of the LL-type sealing device) Oil seal), internal and external oil seals, front cover, and rear block are cracked or loose, whether the front and rear seal covers are biased or not in place, whether the front cover and back block are not in position, etc., and check that the sealing device A side is in the circumferential direction Must not be higher than the end face of the outer ring.
c. After cleaning, the front cover and rear gear of the bearing shall be tested in accordance with the requirements of the test items. The tested dimensions are marked on the outer diameter of the front cover and rear gear. The pressing and closing personnel should select and match according to the marked size Use, eliminate the old front cover.
d. Develop non-retractable bearing torque testing tools to ensure that the non-retractable bearing does not loosen under the specified torque.
e. In addition to the inspection and measurement of bearing components strictly in accordance with the items and standards specified in the "Railway Freight Car Wheel Axle Assembly, Inspection and Management Rules", when performing the visual inspection of the components, the pressure on the outer ring of the bearing and the sealing cover is added Inspection and measurement of dimensions such as chamfer size, tooth mouth wear, tooth mouth width and groove depth. At the same time, the relevant size limits and inspection standards of different types of bearings are incorporated into the "Railway Freight Car Axle Assembly, Inspection and Management Rules".
f. Standardize the specific interference standards of the seal cover and outer ring during bearing inspection. When the sealing cover is selected, the recommended interference is in the range of 0.18～0.28.
g. When new and overhauled bearings leave the factory, the inner diameter and clearance dimensions should be sent to the user along with the bearing. The user should check before use and control the manufacturer’s bearing inner diameter and axial clearance.
h. Control the occurrence of bearing loading and use phenomenon caused by improper packaging and protection in new construction and overhaul. That is, the user department should remove the seal seat from the bearing before the bearing is used (except for the LL type sealing device), and check whether the inner and outer oil seals are flanged, torn, the inner oil seal is not pressed in place, or the position is not correct, and then rotate one by one Check the seal seat to see if there are problems such as jamming, misalignment and geometric deformation of the internal and external oil seals. The seal cover is press-fitted in place to check using a depth vernier caliper or a template check. It must be ensured that the press-fitting surface of the seal cover shall not be higher than the end surface of the outer ring in the entire circumferential direction. If the unqualified bearing is found, the batch of bearings should be stopped and returned to the manufacturer in batches.
i. After the bearing is press-fitted, carry out a running-in test with a speed of not less than 200 r/min and a time of not less than 5 minutes. During the running-in process, workers should carefully listen to the running-in sound of the bearings at both ends, and there should be no abnormal noise when the bearings are rotating. During the running-in process, a thermometer should be used to test the bearing temperature rise. After running-in, the bearing temperature rise should not exceed 40 ℃. During the running-in process, if there are abnormalities, abnormal sounds, friction and other sounds, or there is a large difference in temperature rise on both sides, the running-in time should be extended to 15 minutes. The bearings that fail to run-in should be unloaded and checked carefully. The loading and use of unqualified bearings is prohibited.
j. Strengthen the daily inspection and monthly comprehensive performance verification of the bearing inspection system, bearing single-column correction press, seal cover press-fitting mold, torque test equipment, and bearing press-fitting machine. Refurbish the equipment in a timely manner if the condition of the equipment cannot meet the work quality requirements to ensure the good performance of the bearing inspection equipment.