What are the requirements for sliding bearing metal materials?

The following focuses on the most widely used bearing alloy materials in metal materials:

(1) Bearing alloys, also known as white alloys or babbitt alloys, are mainly alloys of tin, lead, antimony or other metals. Bearing alloys have lower strength and are more expensive. They must be used as bearing lining materials in bearing bushes of bronze, steel or cast iron to form a thinner coating.

(2) Tin-based bearing alloys have the advantages of good plasticity, thermal conductivity and corrosion resistance, and low friction coefficient and expansion coefficient, which are suitable for the production of important bearings, such as large machines such as steam turbines, engines, motors and air compressors. High speed bearing bush. The disadvantages are low fatigue strength and low operating temperature (not higher than 150 ° C), which is more expensive. The wider brand used is ZSnSb11Cu6.

(3) The strength, hardness, thermal conductivity and corrosion resistance of lead-based bearing alloys are lower than those of tin-based bearing alloys, and the friction coefficient is larger, but the price is relatively cheap. Suitable for manufacturing medium and low load bearing bushes, such as automotive, tractor crankshaft bearings, railway vehicle bearings, mill bearings, etc.
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INA overall eccentric bearing noise elimination method

The main task of bearing failure analysis is to find out the main factors causing the failure of INA bearing based on a large amount of background materials, analysis data and failure modes, so as to propose improvement measures in a targeted manner and extend the service life of spherical roller bearings to avoid The bearing has a sudden early failure.

The vibration of the bearing has a significant effect on the failure of the bearing. For example: spalling, indentation, corrosion, cracks, wear, etc. will be reflected in the INA bearing vibration detection. Therefore, by using a special overall eccentric bearing vibration measuring device (frequency analyzer and vibration) The instrument can measure the magnitude of the vibration. The frequency of the vibration can be inferred. The measured value of the abnormal vibration is different depending on the premise of the INA bearing or the installation position of the sensor. Therefore, it is necessary to analyze and compare the measurement values ​​of each machine in advance. After determining the judgment scale.

1. Reason: The overall eccentric bearing has low precision. The method selects the bearing with the specified accuracy grade.

2. Reason: The spindle is bent or the hole of the box is different. The method is to repair the spindle or the box.

3, the reason: the belt is too tight method: adjust the belt to make the elastic appropriate

4. Reason: Poor lubrication method: select the lubricating material of the specified grade and clean it properly.

5, the reason: low assembly quality method: improve assembly quality

6, reason: bearing inner casing running method: replacement of bearings and related wear parts

7. The axial force is too large. Method: Clean and adjust the clearance of the sealing ring. Between 0.2 and 0.3mm, correct the balance of the impeller and verify the static balance.

8, bearing damage method: replace INA bearing
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How to avoid a fire in the bearing heating remover

There are four main reasons for the fire in the bearing heating disassembler: placing the energized bearing heating disassembler on the combustible material or placing it near the inflammable material, causing fire under the long-time high temperature baking; the bearing heating disassembler is not installed with the plug Directly insert the wire head into the socket, which is easy to cause a short circuit and cause a fire; the user does not remove the plug of the bearing heating detacher when leaving, the time is too long, causing the bearing heating detacher to overheat and lead the adjacent combustible material The fire caused by the burning; the resistance wire is used after repeated repairs, which may cause the line to be overloaded and cause a fire.

Therefore, when in use, it is not allowed to place flammable and explosive materials near the bearing heating detacher, and a certain safe distance must be maintained. The bearing heating detacher must be placed on the non-heat-conducting non-combustible material base; the safety interception flow of the bearing heating detacher wire must meet the capacity requirements of the bearing heating detacher, and the industrial bearing heating detacher must be installed separately under any circumstances. Circuit. The wire must be installed with a plug. The wire head should not be directly inserted into the socket. The bearing heating and disassembler wire should be replaced in time. The bearing heating and disassembler without the fuse in the circuit should not be used. The bearing heating disassembler must be taken care of when leaving. Unplug the plug. In the course of use, if there is a power outage, you should also pull out the plug in time, and don't forget it.

For resistance wire repaired many times, it is better not to use it, and a new resistance wire should be replaced. Inflammable and explosive materials are strictly prohibited to be dried by bearing heating and disassembling device; the electric oven should have a device for controlling temperature, which is to prevent the temperature from being too high and prevent the baking time from being too long.
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Spindle bearing selection

The accuracy of the bearing used on the machine tool spindle should be ISOP5 or above (P5 or P4 is the ISO accuracy level, usually from low to high (P0, P6, P5, P4, P2), and for high speed CNC machine tools, machining centers, etc. For high-precision machine tool spindle bearings, ISOP4 or higher accuracy is required. Spindle bearings include angular contact ball bearings, tapered roller bearings, and cylindrical roller bearings.

1, precision angular contact ball bearings

Precision angular contact ball bearings are widely used. The rolling element of an angular contact ball bearing is a ball because it is a point contact (distinguished from the line contact of the roller bearing), so it can provide higher rotation speed and smaller heat generation. And higher rotation accuracy. In some ultra-high-speed spindle applications, hybrid bearings with ceramic balls (usually si3N4 or Al203) are also used. The metal processing reporter believes that compared with the traditional fully hardened steel ball, the ceramic ball material itself gives the ceramic ball bearing the characteristics of high rigidity, high rotation speed, high temperature resistance and long service life, so as to meet the high-end customer's bearing product products. demand.

In terms of the contact angle of the angular contact ball bearing, the contact angles of 15 and 25 are currently popular; usually the contact angle of 15 has a relatively high rotational speed performance, and the contact angle of 25 has a high axial load carrying capacity. Because the choice of preloading has a great influence on the application of precision angular contact ball bearings, such as high load bearing and high rigidity, medium or heavy bearing preloading is generally used; for some high speed and high precision applications, In the early selection of bearings, care must be taken to select the appropriate preload. Metal processing experts say that the preload is generally divided into three types: light, medium and heavy. Generally, light preload is more common. In order to facilitate the use of customers, the world's major bearing manufacturers generally provide pre-grinded bearing end faces and preloaded bearings, which is commonly referred to as the universal paired precision angular contact ball bearing form. This type of bearing eliminates the customer's preload adjustment, which saves installation time.

2, precision cylindrical roller bearings

In machine tool spindle applications, double row precision cylindrical roller bearings are also used, usually in combination with precision angular contact ball bearings or thrust bearings. These bearings can withstand large radial loads and allow for higher rotational speeds. The two rows of rollers in the metal machining in-line bearing are arranged in a crosswise manner. The fluctuation frequency during rotation is greatly improved compared with the single row bearing, and the amplitude is reduced by 60%-70%. These bearings usually come in two forms: NN30, NN30K two series bearing inner ring with ribs, outer ring can be separated; NNU49, NNU49K two series bearing outer ring with ribs, inner ring can be separated, of which NN30K and NNU49K series The inner ring is a tapered hole (taper 1:12), which cooperates with the tapered journal of the main shaft, and moves the inner ring axially to make the inner ring expand, so that the bearing clearance can be reduced or even pre-tensioned (negative clearance) status). Cylindrical bore bearings are usually hot-fitted, with an interference fit to reduce bearing clearance or to pre-tension the bearing. For the NNU49 series bearings that can be separated from the inner ring, the main shaft is usually mounted on the main shaft and then the raceway is finished to improve the spindle rotation accuracy.

3, precision tapered roller bearings

In some machine applications with heavy loads and speed requirements, such as roughing of forgings, wire machines for oil pipelines, heavy duty lathes and milling machines, the selection of precision tapered roller bearings is an ideal solution. Because the roller of the tapered roller bearing is designed for line contact, it can provide high rigidity and load to the main shaft. In addition, the tapered roller bearing is a pure rolling bearing design, which can reduce the bearing operation. Torque and heat to ensure spindle speed and accuracy. Since the tapered roller bearing can adjust the axial preload (play) during installation, this allows the customer to better optimize the bearing clearance adjustment throughout the life of the bearing.
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