miniature ball bearings Precision bearings distinction

Precision bearings and plain bearings should be used to distinguish between the following points:

1, the size of the required value is not the same, high level of accuracy of the product of its size deviation (inside diameter, outside diameter, oval, etc.) than the fine

Value of the low level of product requirements to be smaller;

2, rotating accuracy requirement values ​​self aligning ball bearings‍ are not the same, high level of accuracy of the product of its rotational accuracy (internal diameter of the beating, beating the outer diameter of the end face of the raceway beating, etc.) than the value of the low level of precision to be strict product requirements;

3, the surface shape and surface quality requirements values ​​are not the same, high level of accuracy of the product on its surface shape and surface quality (or channel raceway surface roughness, circular deviation, ditch-shaped deviation) than the low accuracy level the value to be strict product requirements;

4, the accuracy of its products particularly high grade material than the material properties of the general levels of precision products more favorable.

Precision bearings in accordance with ISO double row ball slewing bearing‍ grading standards are divided into:. P0, P6, P5, P4, P2 successively higher grades, where P0 is the general accuracy and precision are other grade levels. Of course, different classification criteria, different types of bearings, their method for classifying different, but the meaning is the one to. Performance requirements on the use of precision bearings rotating body with high runout accuracy, high-speed, low friction and friction change.       

LYHY flanged ball bearing Methods to improve cooperation

In order to improve the accuracy of the actual mating bearing installation, you must not make use of measurement methods and tools bearing deformation of the flanged ball ‍bearing bore and the outer dimensions of the actual mating surface precision measurement, the measurement can be related agricultural bearings‍ to inner and outer diameters all items to be measured, and the right to make a comprehensive analysis of the measured data, as a data, precision worthy of the shaft and the bearing seat hole the size of the installation site. In the actual measurements made ​​with the corresponding dimension of the shaft and housing bore and geometry, the measurement should be carried out when the bearing at the same temperature.

In order to ensure a higher actual vertical mill bearing‍ match results, and the surface of the shaft and the bearing seat hole match, the roughness should be as small as possible.

In making these measurements, should be in the outer and inner bore of the bearing and the corresponding surface on the shaft and housing bore at both sides of the assembly near the chamfer, respectively, showing the maximum deviation can be made in two directions marked so in the actual assembly, so that the maximum deviation of the two sides match aligned in the same direction, so that after assembly, the two sides of the deviation can be partially offset.

The purpose of making two directional signs, that can compensate for deviations into account, even if the respective ends of the supporting improved rotational accuracy, and make spherical bearings‍ the two ends of the housing bore and between the journal bearing concentricity error partially eliminate . Implement measures to strengthen the surface of the mating surfaces, such as sand blasting, with a diameter slightly larger than the column precision plug the hole once the plug, etc., are beneficial to improve the fitting accuracy.

high speed bearing Improve Accuracy

After the high speed ‍bearings installed in the host, such as measuring spindle radial runout, measured values ​​can be found in each of its revolutions have some change; continuous measurements, can be found after a certain number of revolutions, the repetition of this change will be approximately appears. precision spindle bearings‍ Indicators to measure the extent of this change is cyclic rotation accuracy, approximately repeated changes in the number of revolutions required precision rotation cycle on behalf of "quasi-periodic" values ​​vary within a large amplitude quasi-periodic, cyclic rotation accuracy is poor .

If properly pre-load on the spindle, the speed gradually increased to nearly the speed of work to implement the "run-in" the role of the bearing can improve the accuracy of the spindle rotation cycle.

6 Install accuracy calibration method

After the angular contact ball bearing into the spindle, install precision calibration sequence is as follows (with shaft diameter of 60 100mm ordinary lathe for example):

(A) measuring the shaft and housing bore size, to determine with precision bearings, with the following requirements:

Take the inner ring and the shaft interference agricultural bearings‍ fit, the amount of interference 0 ~ + 4μm (at light load, when precision is 0); take the outer ring and the bearing bore clearance fit, clearance volume 0 ~ + 6μm (but at the free end of the bearing when using angular contact ball bearings, but also increase the gap); shaft and housing bore surface roundness error in 2μm or less, face parallelism bearing spacer used in the 2μm or less, the end face of the shaft shoulder end foreign beating in 2μm or less; retaining shoulder of the housing bore axis beating 4μm below; cover the front end face of the spindle axis beating 4μm or less.

miniature ball bearings a fixed end bearings mounted on the shaft before

After the bearings were cleaned thoroughly washed with clean kerosene, grease lubrication, the first containing 3% to 5% of the grease into the bearing organic solvents for degreasing and cleaning, and then quantitative grease gun oil filled bearing (accounting bearing space volume of 10% to 15%); Full complement cylindrical roller bearings‍ heating bearings make heating 20 ~ 30 ℃, oil presses the bearing into the shaft; pressure in the tight sets with suitable pressure shaft and bearing against the end face axially the spring balance tape volumes on the bearing outer ring, pre-load starting torque measuring method stipulated check whether a substantial change (even if the bearing is correct, but due to meet or maintain the deformed frame, pre-load there; positioning changes possible).

(3) the bearing shaft assembly into the seat hole

Heated seat hole so that heating 20 ~ 30 ℃, with continuous gentle pressure on the bearing shaft assembly into the housing bore;? Before adjusting cover, tighten the amount of the front cover of 0.02 ~ 0.05μm, to the outer end face of the bearing housing benchmark indicator of the conflict in the journal header surface, the axis of rotation measured beat, require error 10μm or less; will dial gauge positioned on the shaft hole in precision spindle bearings‍ the surface of the back seat of the header conflict, the rotation axis to measure the bearing housing bore concentricity before.

(4) the free end of the bearing may be selectively placed in the position deviation offset mounted to the bearing support position, to offset possible concentricity and roundness deviation of the deviation between each other.‍

LYHY flanged ball bearing precision bearings configuration issues

For some high-precision bearings, its configuration requirements are very high, today we have to introduce a configuration problem on precision bearings.

Traditional applications of precision machine tool spindle  flanged ball ‍bearings are, depending on the machine spindle processes have different requirements. In general, the lathe spindle is used at lower speeds and greater cutting metal cutting load. This type of transmission of the driving torque of the high precision bearings‍ nspindle usually through the pulley or gear. This means that the spindle drive end load is also quite large.

Such applications do not require high speed of the more important parameter is the stiffness and load-carrying capacity. A very common method is to install a working end of the spindle-row cylindrical roller bearings and a double row angular contact thrust ball bearings, while at the end of the spindle drive uses a double row cylindrical roller bearings. This configuration ensures a long working life and excellent rigidity, to produce high quality parts. Moreover, the bearings can operate stably in terms of kinematics is concerned, because the two types of bearings (radial and axial) were carrying the load applied to the spindle (in fact, in order to prevent angular contact thrust ball bearing bearing Full complement cylindrical roller bearings‍ diameter to the load, the outer diameter of a special foreign ensure it never tolerances can contact bearing).

In the design of these types of spindles (which is usually applied when the heavy load), a bearing located about the axis of where a rule of thumb the distance between the centers of the front and rear support bearings for the 3-3.5 times the diameter.

In that require higher speeds (ie, high-speed machining centers or internal grinding), you need to find a different bearing solutions. Obviously, the need to make Other bearing‍ sacrifices in rigidity and load carrying ability in these cases. High-speed applications usually by direct-motor and / or direct drive spindle coupling (the so-called motor spindle).

high speed bearing Ceramic Bearings

Cheng as an important machine parts, because of its incomparable metal bearing excellent performance, high temperature, super-strength materials such as the new world dominate.

Advantages

First, since the ceramic almost afraid of self aligning ball bearing‍ corrosion, so the ceramic rolling bearings suitable for operation under harsh conditions covered with corrosive media.

Second, since the ceramic rolling the ball lower density than steel, but much lighter weight, so when you rotate the outer ring centrifugal effect can be reduced by 40%, thus greatly extended service life.

Third, the expansion and contraction of the ceramic affected smaller than steel, and therefore the gap of the bearing is constant, the bearing allows the temperature changes Taper roller bearings‍ more severe environment.

Fourth, as the ceramic high modulus of elasticity than steel, when the force is not easy deformation, and therefore help to improve the operating speed and achieve high accuracy.‍

miniature ball bearings Applications

Medical equipment, cryogenic engineering, optics, high-speed machine tools, high-speed motor, printing machinery, food processing machinery.

In the field of aerospace, marine, nuclear industry, taper roller bearing‍ petroleum, chemical industry, textile industry, machinery, metallurgy, electric power, food, locomotives, subway, high-speed machine tools and research needs of national defense and military technology in high-temperature, high-speed, cryogenic, flammable, explosive, strong corrosion, vacuum, electrical insulation, non-magnetic, dry friction and other special conditions of work, replace the indispensable role of ceramic bearings are being increasingly recognized people.

With the continuous advancement of processing technology, increasing the level of technology, the cost of ceramic bearings declining, has been in some high precision applications in Angular contact ball bearings‍ the field of small-scale tip, gradually extended from the past only to the national economy in various industrial fields, the market price gradually approaching practical, to achieve an acceptable level users, the wave of large-scale applications of ceramic bearings have been coming!