Can you install the deep groove ball bearing?

1. When installing the bearing, it should be evenly stressed and cannot be hammered directly. For example, if the interference is large, the bearing should be placed in an air-heating furnace or oil furnace with automatic temperature control, and the heating temperature should be strictly controlled below 120°.

2. The bearing with nylon cage can work continuously for a long time under the temperature -40°-120°. It should not exceed 4 hours at 150°, and the short-term temperature should not exceed 180°.

3. The warehouse where the bearings are stored should be clean, dry and not allowed to be stored in the same warehouse with the chemical products. The relative humidity should not exceed 65%, and the bearings are not allowed to be stored on the ground.

4. The stock bearings should be cleaned every year for rust-proof packaging.http://www.zysbearing.com/

Which caused the frequent damage of rolling mill bearings?

After analysis of effective data, the main forms of rolling mill bearing damage are fracture, wear and pitting.

Damage form one: Fracture: inner and outer ring fracture, rolling element rupture, cage fracture

The outer ring fracture is mainly caused by the excessive load and the insufficient bearing pressure.

In addition to the cyclic load, the inner ring is connected with the roll neck by the interference fit during installation. There is a positive tensile peripheral stress. As long as micro cracks are formed on the inner ring, they will rapidly spread and then cause fracture.

In addition to the above reasons, another reason for the fracture is that the oil and gas supply in the roller box is insufficient or interrupted, causing the bearing to heat up and then lock, and then causing damage to the inner and outer rings, the cage and the rolling elements.

Damage form two:  How is wear and pitting caused?

Most of the wear is caused by the relative rotation of the roll neck and the inner hole.

There are two main reasons for pitting: the bearing material is unqualified, caused by improper heat treatment. Foreign matter enters into the roller box, and pitting occurs during the running of the bearing.

In addition, due to improper operation, the copper bracket is deformed. When the roller enters the bearing housing, the ball rubs against the inner sleeve and then scratches the inner sleeve, so that the roller is inflexible during operation, causing bearing failure.

The height of the roll gap on both sides of the rolling mill is inconsistent, which causes the bearing to be stressed at a certain point due to uneven force during the running of the roll, thus causing bearing failure.

The working principle of deep groove ball bearings

Deep groove ball bearings are suitable for high speed operation, low vibration and low noise, and they are extremely durable and require no maintenance. Deep groove ball bearings have the features of small friction coefficient, high limit speed, various sizes and forms, and they can be used in precision instruments, low noise motors, automobiles, motorcycles and general machinery. It is the most widely used type of bearing in the machinery industry. They mainly bear the radial load and can also withstand a certain amount of axial load. When it increases the radial clearance of the bearing, it has certain angular contact bearing performance and can withstand radial load and axial combined load.

The basic deep groove ball bearing consists of an outer ring, an inner ring, a set of steel balls and a set of cages. There are two types of deep groove ball bearings: single row and double row. The deep groove ball structure is divided into two types: sealed and open. The open type means that the bearing does not have a sealing structure. The sealed deep groove ball is divided into dustproof seal and oil proof seal. The dust seal cover material is stamped from steel plate, which is simple to prevent dust from entering the bearing raceway. The oil-proof type is a contact type oil seal, which can effectively prevent the grease inside the bearing from overflowing.

The type code of deep groove ball bearing is 6, and the double row deep groove ball bearing code is 4. It is the most common and widely used class 0 bearing. 

Full ceramic bearings are not hybrid bearings

Usually, people thought that bearings are actually hybrid bearings. So, today we will talk about the difference between full ceramic bearings and hybrid bearings? 

Ceramic Bearings

Full ceramic bearings consist of ceramic rings, ceramic balls, and synthetic cage made from PEEK or PTFE material or no cage at all. They are highly resistant to acids and alkalis, so they are suitable for corrosive environments. Silicon nitride (Si3N4) bearings can be heated to temperatures of 800°C without cage.

Full ceramic bearings are also non-magnetic, so they can be used in medical devices for strong magnetic field. However, the greater hardness of ceramic bearings also means greater brittleness, so they can not bear shock load. 

Hybrid bearings

Hybrid bearings are a mixture of ceramic and steel materials. They use ceramic balls, but are paired with metal inner and outer rings. Therefore they are suitable for higher speeds conditions. 

Despite the small difference in design, the requirements of hybrid bearings have big different from full ceramic bearings. For example, full ceramic bearings do not require lubrication, but hybrid bearings need unless they are used at very low speeds. Precision hybrid bearings with a high-speed cage are capable of very high speeds, so they can be used in machine tool spindles. 

ZYS can design the bearings for the customers with the technical requirements and working conditions.

Configuration type of common rolling mill bearings

(1) Spherical roller bearings.  The configuration of the early rolling mill bearings on the rolling mill is different from the present. At that time, two sets of spherical roller bearings were mainly installed side by side on the same roller neck. This configuration basically meets the production conditions at that time, and the rolling speed can reach 600 rpm.

(2) Four-row cylindrical roller bearing + thrust bearing. The inner diameter of the cylindrical roller bearing is tightly matched with the roll neck, and it can bear radial force.  The cylindrical roller bearing has advantages of large load capacity, high limit speed, high precision, easy processing, low production cost, convenient installation and disassembly and the inner and outer rings can be separated.  The thrust bearing bears axial force, and the specific structure type can be selected according to the characteristics of the rolling mill. While for heavy-duty low-speed, we can equip with thrust roller bearings to withstand the thrust load with a small axial clearance. When the rolling speed is high, it is equipped with angular contact ball bearings so that speed limit is high and the axial clearance can be controlled. This type of bearing configuration not only has long bearing life, high reliability, but also has many advantages such as high precision and easy control of rolling products. Therefore, it is widely used in wire rod mills, sheet mills, foil mills, and support rolls for cold rolling mills and hot rolling mills.

(3). Four-row tapered roller bearings. The tapered roller bearings can withstand both radial and axial forces, and no need to configure thrust bearings. The inner diameter of the tapered roller bearing is loosely matched with the roll neck. It is very convenient to install and disassemble, but sometimes it will cause sliding creep due to the loose fit. Therefore, the inner diameter is often processed with a spiral oil groove. This type of configuration is widely used in the working roll of four-roll hot rolling mill and a cold rolling mill, and roll for blanking machine, steel beam rolling mill.

If you want to know more, please visit http://www.zys-bearings.com/ or send e-mail to zysdong@gmail.com. 

Daily maintenance of bearings

Bearings are an important part of machinery. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement, and ensure its rotation accuracy. Maintenance work is the top priority for bearings to work properly, maintain performance, and extend life. Everyone should take it seriously.

Next, let's take a closer look at the daily maintenance work of the bearings.

First, keep the bearings lubricated and clean

Before inspecting the bearing, clean the surface of the bearing first and then remove the parts around the bearing. Pay special attention to the oil seal, which is a very fragile part. Please be careful when inspecting and disassembling the bearing to avoid damage to the part. If you have been experiencing bad symptoms when inspecting the oil seal of bearing and its surrounding parts, be sure to replace it to avoid damage to the bearing caused by a bad oil seal.

Second, to ensure the quality of bearing lubricants

The quality of the lubricant has a direct impact on bearing service life. The inspection method for the bearing lubricant is as follows: the lubricant is rubbed between the two fingers, and if there is a contaminant, it can be felt; or a thin layer of lubricant is applied on the back of the hand, and then the sealing is checked. Then it is to replace the lubricant of the bearing.

Third, the working environment of the bearing

When inspecting bearings, never expose them to contaminants or moisture. If the work is interrupted, cover the machine with a piece of oil-paper plastic or similar material. The working environment of the bearing is also very important. 

Fourth, the bearing seal

The purpose of bearing sealing is to prevent dust, moisture and impurities from entering the bearing, but also to prevent the loss of lubricant. A good seal ensures that the machine works properly, reduces noise and extends the life of the parts.

The above is the relevant introduction of the daily maintenance work of the bearing. It is mainly explained from four aspects. In fact, these four aspects are also related to each other. Therefore, bearing maintenance work is carried out closely around the four words of clean, lubrication, sealing and environment.

Installation and maintenance of slewing bearing

1. Slewing bearings require careful handling.
2. Slewing bearings should always be transported and stored in horizontal position and be stored in dry roofed areas.
3. Use eyebolts for horizontal handling. Impact, particularly in radial direction, must be avoided.
4. The surface of slewing bearing should be applied with anti-corrosion oil, and the anti-corrosion period is 6 months. Long storage (as backup, for example) periods will require special preservation.

Requirements on supporting structures

1. The support in the companion structures must be kept aligned to the track center.
2. In order to prevent local overload and ensure smooth rotation, the supporting structures should be processed to remove internal stress after all the welding procedures. The contact surfaces for the bearing should be machined carefully and should be within flatness tolerances.

General information about Bearing test machine

Bearing life test machine   

       Bearing life test results is an important index of comprehensive evaluation of bearing quality. It can reveal the quality level of bearing structure design, manufacturing process, material and lubrication etc.

      This series of machine is controlled by industrial computer automatically. The load, speed, operation time and other main parameters can be preset, and the machine can work according to the set procedures. The test machine can also monitor, record automatically on bearing load, temperature, vibration, motor speed, current and other parameters. When the testing bearing failure or something wrong with the test machine, the machine will alarm downtime and record down the reason automatically, to realize unattended and intelligent management.

    Auto bearing testing machine    

     This series of machine are realized the computer automatic control, monitoring test parameters, recording, alarm downtime and other functions.

     This series of machine test subject design is unique, simulation accurately, high machining accuracy, high components configuration, so as to ensure the stability and reliability of the bearing test.

    Sealed bearing testing machine   

     This kind of machine are often used to evaluate the bearing performance of a particular level and the durability of the bearing performance, such as the seal, friction, high-speed, high temperature resistance performance. Control mode can be automatic computer control or manual control.

    Bearing parts testing machine      

    A lot of experiments and data statistics show that when bearing fatigue failure, the most probability is roller failure. Therefore, steel ball contact fatigue testing machine and roller fatigue testing machine are used to test the fatigue life of rolling elements. And then study the internal relationship between rolling element's fatigue life, material, manufacturing process, finished product quality etc.

Three Methods for Identifying Bearing Faults

Bearing as a precision part of mechanical equipment, how to improve the productivity of the factory, the first mechanical equipment must be the best performance. And mechanical equipment performance use of one of the largest relationship-bearing. Therefore, the factory in production and processing, must be mechanical equipment in the bearing good inspection. For safety reasons. China bearing network sharing bearing fault identification method, we hope to help.

1. Recognizing by sound

     There is a need for a rich experience to identify the sound through sound . It must be adequately trained to recognize the bearing sound and non - bearing sound . To do this , it should be done as much as possible . The sound of the bearing can be clearly heard on the housing with a microphone or a listening stick .

2. Identifying by working temperature

      This method is a comparative identification method, which is only used in situations where the operation state is not too varied. For this reason, continuous recording of temperature must be carried out. When failure occurs, the temperature will not only rise. Irregular changes will also occur. It is advisable to combine this method with the sound recognition method.

3. Identified by the state of the lubricant

This method is especially effective for bearing or large bearing which can not be observed near by sampling analysis of lubricant, judging whether the lubricant is mixed with foreign body or metal powder according to the degree of dirt and whether the lubricant is not mixed with metal powder.

Method of Judging Grease Metamorphism

In order to provide better performance, the bearings are lubricated by lubricating grease, which can reduce the friction and temperature of the bearings, if the grease is bad. Not only does not play a related role, but is more adverse to the use of bearings, so we must learn how to buy grease to tell whether the grease has deteriorated.

  

Method of judging grease metamorphism

1. Oil flow observation method

    Take two measuring cups , one of the lubricating oil to be inspected , the other empty on the desktop , lift the measuring cup full of lubricating oil away from the table top 30 - 40 cm and tilt , let the lubricating oil slowly flow into the empty cup , observe the flowing condition , the quality good lubricating oil oil flow should be slender , uniform and continuous , if the oil flow is lost or slow , and there is large flow of oil , the lubricating oil has deteriorated .

2. Hand twisting

    Twisting lubricating oil between thumb and index finger repeatedly grinding, a better lubricating oil hand feel lubricity, less debris, no friction, if feel the sand between fingers such as a greater sense of friction, it shows that there are many impurities in the lubricating oil. New lubricating oil should be replaced if it cannot be used again.

3.Illumination method

     On sunny days, use a screwdriver to lift the lubricating oil at an angle of 45 degrees to the horizontal level. Compare the sunlight and observe the oil droplets. Under light, you can clearly see that the lubricating oil is good without debris and can continue to function. If there is too much debris, replace the lubricating oil.

4. Oil drop trace method

    Take a clean white filter paper, drop a few drops on the filter paper, after oil leakage, if the surface of black powder, with the hand touch has a sense of resistance, then the lubricating oil has a lot of impurities. Good lubricating oil without powder, touch dry and smooth with hands, and yellow marks.