Keep Rolling mill bearings

Cross roller bearings is a precision mechanical components, their storage and safekeeping have more stringent requirements.

(1) Storage Temperature: front bearing factory are coated with anti-rust oil temperature is too low or too high will lead to deterioration of anti-rust oil, room temperature should be controlled at 0-25 ℃.

(2) Storage humidity: excessive humidity can cause corrosion of bearings, the relative humidity in the warehouse should be kept to 45% -60%.

(3) warehouse environments: Four-Row Tapered Roller Bearings best kept separate when stored must be shared with other items, other items must not be stored with acids, bases, salts and other chemicals. Bearings should be placed off the ground, away from the heating pipes.

(4) periodic inspection: according to the provisions bearings rust, every 10-12 months, regularly check again. If it is found rusting seal packaging, should be re-seal packaging.

Mill bearing Manufacturing Technology

Development of oil film Four-Row Taper Roller Bearing main parts, began in the late 1950s, in the case of a no pattern, nor information, three non-proprietary equipment carried. Development of oil film bearing the main parts, and easy, from material selection, process route, processing methods to special tooling design and manufacturing has a set of procedures. From the choice of materials, taking into account the friction pairing sleeve material, drogue process of forging, steel sleeve and liner combination of process steel sleeve friction material; from the process line, to meet the cone, bush of the technical requirements, but also use the existing processing equipment, which in itself requires a good combination of theory and practice, for example, the inner surface of the steel jacket of how physical (including machining) and chemical treatment in order to increase the binding force ; in the processing method, we know, it is the civilian liner sleeve and the highest precision, surface roughness sleeve Ra0.05μm (bush is Ra0.2μm), high precision geometric deformation is difficult to control, surface roughness low, the need for super-finishing, the surface does not allow multiple prism, spiral, chatter and the like; design and manufacture of special tooling, is also very important, it is to achieve processing methods to ensure that critical machining accuracy.
Early 1960s, completed the development of the film Four-Row Cylindrical Roller Bearing the main parts of general machine tools manufacturing. The late 1960s, Taiyuan Heavy Machinery Factory built a rolling mill oil film bearing specialized production workshop, and began manufacturing rolling mill oil film bearing of the whole of the New.

Principle Rolling mill bearings

four row cylindrical roller bearings is used for roll neck metallurgy, mining and other rolling mill stand, roller bearings used. Usually cylindrical roller bearings under radial load, deep groove ball bearings or angular contact ball bearings, thrust or radial design or design of the tapered roller bearing axial load. Now they use oil mist lubrication oil lubrication or cooling lubricant bearing manner. Principle folded edit this section
Oil film four row cylindrical roller bearing technology, is a systems engineering technology, and also a multi-disciplinary comprehensive engineering technology, its development speed and the ability to support the formation of a reflection of the pace of development of Chinese industry and the level achieved. Have a brief discussion of the main aspects operation technology, manufacturing technology, testing technology, theoretical research, product development, complete sets of capacity

Rolling type selection

A According to the bearing load size, direction and nature
①, when the load is small and stable, it is appropriate roller bearings.
②, when the bearing is only subjected to radial load, the choice of radial ball bearings or radial cylindrical roller bearings; when the bearing is only subjected to axial load, thrust ball bearings can be used.
③, when the Bearing life testing machine is simultaneously subjected to axial load and radial load, and radial load should load A relative value R of an axial considered.
When R A is smaller than a lot of the time, the choice of radial ball bearings.
b when A <R, the selection of angular contact ball bearings or tapered roller bearings.
c when the A> R, the choice of the contact angle of the cone large angular contact ball bearings and a large cone angle roller bearings.
d When A much larger than R, it can be thrust and radial bearings used in combination, respectively axial and radial loads.
B according to the speed of the bearing
1, when the size, with the same precision, limit ball bearing roller bearing ratio is high, so the ball bearing is easy for high speed shaft.
2, by the axial load greater speed shaft, the best selection of angular contact ball bearings, thrust ball bearings rather than choice. Due to high speed, the centrifugal force of the rolling elements great bearing worsen working conditions.
C - Particular requirements for bearings
The radial dimensions of the components is limited and radial load and a great time, the selection of needle roller bearings.

Advantages of hybrid bearings

Hybrid ceramic bearings may be less common, and hybrid ceramic bearings are mainly configured by the inner and outer rings of bearing steel / stainless steel + ceramic balls + PA66 / stainless steel holder + 2RS / ZZ combination. Hybrid ceramic bearing has the following four advantages during use.
(1), high temperature, thermal expansion coefficient ceramic ball at high temperature because of the temperature of the environment will not lead to bearing balls swell, thereby greatly enhancing the overall bearing temperature, plain Sealed bearings temperature of about 160 degrees, with ceramic balls You can reach more than 220 degrees.
(2), high speed ceramic ball with no self-lubricating properties, low coefficient of friction ceramic balls, so ceramic ball bearings with high speed. Count statistics with ceramic ball bearings are generally bearing speed 1.5 times more speed.
(3), long life, with ceramic balls can not add any oil, grease means that even kill, the bearing can still operate, thus avoiding the occurrence of fat to get rid of because of premature bearing damage caused by the phenomenon of ordinary bearing. According to us ceramic ball bearing life after testing and feedback of some customers is 2-3 times the normal bearing.
(4), insulated with ceramic ball bearings, can make between the inner and outer ring of the bearing insulation, because the ceramic balls is an insulator between the inner and outer rings of bearings with ceramic balls, you can achieve an insulating effect. This enables Dental bearing It can be used in a conductive environment. This is the biggest advantage of hybrid ceramic bearings.

High temperature bearings and plain bearings are different models. Usually two cases:

1. super-precision bearing parts bearing steel tempered by a high temperature, then set code required to JB / T2974 (the part by tempering at high temperatures, the working temperature of up to 150C °, which code for the / S0; parts through hot temperatures, the working temperature of up to 200 ° C, which code for the / S1; parts tempered at high temperature, the working temperature up to 250 ° C, which code for the / S2; parts tempered at high temperature, work temperatures up to 300 ° C, which code for the / S3; parts tempered at high temperature, the working temperature up to 350 ° C, which code for the / S4).
2. Ball screw support bearing parts made of heat resistant steel, then set code required to JB / T2974 (the material is Cr4Mo4V, then set code is / HN; material Cr14Mo4, then set code is / HN1; material Cr15Mo4V, then set code is / HN2; material W18Cr4V, then set codenamed / HN3).

Precision Cylindrical Roller Bearings

In the machine tool spindle applications, double row precision cylindrical roller bearings will be used to generally contact ball bearings or turbocharger bearings and precision angular composite applications. These bearings can withstand greater radial load and allows a higher speed. Bearing in two rows of rollers arranged in a cross pattern, rotation fluctuation frequency significantly higher than Four-Row Tapered Roller Bearings, amplitude reduced by 60% to 70%. Such bearings generally come in two forms: NN30, NN30K two series bearing inner ring with ribs, outer ring separable; NNU49, NNU49K two series bearing outer ring with ribs, separable inner ring, which NN30K and NNU49K series inner ring tapered bore (taper 1:12), with the tapered journal spindle with axial movement inner ring, the inner ring can swell, so the bearing clearance can be reduced even bearing preload (negative clearance state). Cylindrical bore bearings usually thermal loading, using an interference fit reduced bearing clearance, or preload the bearings. NNU49 inner ring separable bearings, usually mounted on the inner shaft and then to finish the race in order to improve the accuracy of spindle rotation.