Single Row 6003-2Z SKF Deep Groove Ball Bearing

CN: normal group radial clearance; Usually used only in combination with the following letters to indicate a narrow or offset gap range H: narrowed clearance range, equivalent to the upper half of the original clearance range L: narrowed clearance range, equivalent to the lower half of the original clearance range P: Offset clearance range, equal to the composition of the upper half of the original clearance range and the lower half of the next set of clearance ranges The above letters also apply in the corresponding sense to the following gap groups: C2, C3, C4, and C5, for example, C2 C2: The radial clearance is smaller than that of the common group C3: The radial clearance is larger than that of the ordinary group C4: Radial clearance greater than C3 C5: Radial clearance greater than C4

1. Accuracy improvement method After SKF deep groove ball bearing is installed in the main engine, it can be found that the measured value of each revolution has a certain change, if the radial runout of the main shaft is measured; When continuous measurements are made, it is found that the change is approximately repeated after a certain number of revolutions. The index to measure the degree of variation is the rotation accuracy of the cycle, and the number of revolutions required for the approximate recurrence of the change represents the "quasi-period" of the rotation accuracy of the cycle. If the amplitude of the magnitude change within the quasi-period is large, the rotation accuracy of the cycle is poor. If the spindle is properly pre-loaded, the speed will gradually increase to close to the working speed, in order to implement the bearing "running-in" role, can improve the spindle rotation accuracy. 2. A method to improve bearing accuracy A factory tried to produce precision instruments, spindle with 6202 / P2 bearing and its accuracy still can not meet the requirements, after thickening the journal and making raceway on it to replace the inner ring, and precision measurement of the ball, the size of each three grain a group, each group of ball take close to 120 degrees of separation, because of the reduction of a heavy machining surface, and reduce a heavy matching surface, At the same time, the stiffness of shaft SKF deep groove ball bearing system is improved, and the distribution of the maximum three grains and the minimum three grains of steel balls is close to the same distance, and the rotation accuracy of the shaft is improved, so that the accuracy requirements of the instrument are met. 3. Comprehensive verification method of installation accuracy After the angular contact ball bearing is loaded into the spindle, the verification sequence of the installation accuracy is as follows (take the ordinary lathe with an axle diameter of 60/100mm as an example) : (1) Measure the size of the shaft and bearing seat hole to determine the matching accuracy of the bearing. The matching requirements are as follows: Interference fit between the inner ring and the shaft, interference 0 ~ +4μm(0 in light load, high precision); The outer ring and the bearing seat hole adopt a clearance match, the clearance is 0 ~ +6μm(but in the free end of the bearing using angular contact ball bearing, can also increase the clearance); The roundness error of shaft and seat hole surface is below 2μm, the parallelism of the end face of the spacer ring used by SKF deep groove ball bearing is below 2μm, and the runout of the inner end face of shaft shoulder and the outer end face is below 2μm; The beating of bearing seat hole shoulder to axis is below 4μm; The runout of the inner end of the spindle front cover facing the axis is below 4μm. (2) The installation of the fixed end front bearing on the shaft The SKF deep groove ball bearing is thoroughly cleaned with clean cleaning kerosene. For grease lubrication, the organic solvent containing 3% ~ 5% grease is injected into the bearing for degreasing cleaning first, and then the oil gun fills the bearing with quantitative grease (accounting for 10% ~ 15% of the bearing space volume); Heating the bearing makes the temperature rise 20 ~ 30℃, and loading the bearing into the shaft end with an oil press; The clamping sleeve is pressed on the shaft and the bearing end face is held against the appropriate pressure to make it axial positioning; Roll the tape of the spring scale on the outer ring of the bearing, and check whether the specified preload changes substantially by measuring the starting torque (even if the bearing is correct, the preload may change due to the deformation of the fit or cage). (3) Load the bearing shaft assembly into the seat hole The heating seat hole makes the temperature rise 20 ~ 30℃, and the bearing is changed with continuous light and slow pressure. Shaft assembly loading seat hole; Adjust the front cover, so that the fastening amount of the front cover is 0.02 ~ 0.05μm, to the outer end face of the bearing seat as the benchmark, the dial meter head conflict on the journal surface, the shaft rotation measurement of its runout, the required error is less than 10μm; The dial gauge is positioned on the shaft, the dial head contradicts the inner surface of the backseat hole, and the shaft is rotated to measure the coaxiality of the front and rear seat holes of the bearing seat. (4) Selectively place the free end bearing in a position that may offset the deviation and install it in the supporting position after the bearing seat to offset the mutual roundness deviation and coaxiality deviation as far as possible.

1. Cleaning of bearings When disassembling SKF deep groove ball bearings for maintenance, the bearing appearance should be recorded first, the residual stock of lubricant should be confirmed, and the bearing should be washed after sampling the lubricant for inspection. As a cleaning agent, the common use of gasoline, kerosene. The cleaning of the bearing removed is divided into coarse cleaning and fine cleaning, respectively, in the container, first put the metal mesh bottom, so that the SKF deep groove ball bearing does not directly contact the dirt of the container. During rough cleaning, if the bearing rotates with dirt, the rolling surface of the bearing will be damaged, which should be paid attention to. In the crude cleaning oil, use a brush to remove grease and adhesion, roughly clean, into fine washing. Fine washing is to carefully clean SKF deep groove ball bearing while rotating in cleaning oil. In addition, cleaning oil should also be kept clean. 2, bearing maintenance and judgment In order to judge whether the disassembled SKF deep groove ball bearings can be reused, it is necessary to check after the bearings are cleaned, carefully check the status of raceway surface, rolling surface, mating surface, cage wear, the increase of clearance of SKF deep groove ball bearings and whether there is damage and abnormality related to the decrease of dimensional accuracy. For non-separated ball bearings, the inner ring is supported horizontally with one hand and the outer ring is rotated to confirm whether it is smooth. SKF deep groove ball bearings and other separated bearings can be checked on the raceway surface of the rolling body and outer ring respectively. Because large bearings can not be rotated by hand, pay attention to check the appearance of rolling body, raceway, cage, guard surface, etc. The higher the importance of bearings, the more careful inspection must be. The judgment of whether it can be reused is determined by considering the degree of damage to bearings, mechanical properties, importance, operating conditions and the period to the next overhaul. However, if there are the following defects, they can no longer be used and must be replaced with new SKF deep groove ball bearings: (a) There is a crack or notch on any of the inner ring, outer ring, rolling body or cage; (b) There is a break on any of the ferrule and rolling body; (c) There are significant stuck injuries on raceway surface, guard edge and rolling body; (d) Significant cage wear, or significant rivet relaxation; (e) Rust and injury on raceway surface and rolling body; (f) Serious indentation and scratches on the raceway surface and rolling body; (g) There is significant creep in the inner diameter surface or outer diameter surface of the inner ring; (h) Significant discoloration due to heat; (i) Bearing sealed with grease, the damage of sealing ring or dust cover is obvious.