Cold extrusion is a forming process that uses plastic deformation of a metal material to obtain a part of the desired shape, size, and mechanical properties, so the blank volume is equal to the part volume.
The determination of the diameter of the blank is critical. It determines the degree of deformation of the positively extruded part. A reasonable diameter size ensures the balance of the degree of deformation of the two extrusions, so as to reduce the deformation resistance during extrusion and avoid the extrusion of the imported bearing parts. Defects extend the life of the mold. According to the experience of extruded bearing steel, the compression ratio of the positive extrusion section of the complex opening part is preferably controlled within 50%.
First, the cold extrusion process according to the angular contact ball bearing parts shape and dimensional accuracy, the use of blanks to prepare a higher quality lathe blanking method, the billet after annealing softening, rolling, pickling, and then phosphating, saponification, Finally squeeze.
Second, in the strength theory and design calculation of the cold extrusion die, the die is generally regarded as a thick-walled cylinder subjected to uniform pressure. For thick-walled cylinders whose INA bearings are subjected to internal working pressure, excessive tangential stress at the inner diameter is the main cause of cracking and damage of the mold. Therefore, when calculating and verifying the strength, each inner surface should be checked. The resultant stress is such that it does not exceed the tensile yield limit of the material.
Third, the maximum shear stress strength theory believes that the cause of material damage is the maximum shear stress, as long as the maximum shear stress reaches a certain value (ie, the maximum shear stress that is destroyed during simple tensile compression), the material will be destroyed.
Reduce the vibration of the rolling surface grinding superfine, obtain good surface processing shape accuracy and surface texture quality to reduce vibration, the grinding super machine tool must have good vibration resistance, the important structural parts such as the bed body have vibration absorption, super precision machine tool The oilstone oscillating system has good anti-vibration performance; the grinding speed is improved. The foreign grinding 6202 outer raceway generally adopts 60,000 electric spindles, and the grinding speed is above 60m/s. It is generally much lower in China, mainly by the main shaft and main bearing. Performance limitations. In high-speed grinding, the grinding force is small, the grinding deterioration layer is thin, it is not easy to burn, and the machining precision and efficiency can be improved, which has great influence on the low-noise angular contact ball bearing; the dynamic and static stiffness of the main shaft and its speed characteristics are low noise. INA bearing grinding vibration has great influence, the higher the rigidity, the less sensitive the grinding speed is to the change of grinding force, the smaller the vibration of the grinding system; the higher the rigidity of the spindle bearing, the random dynamic balance technology is used to improve the grinding spindle Vibration resistance. The vibration speed of foreign grinding heads (such as Gamfior) is about one-tenth of that of domestic general spindles; it is important to improve the cutting performance and dressing quality of grinding wheel. The main problem of the current grinding wheel in China is that the uniformity of the structure is poor, which seriously affects the super-processing quality of the low-noise angular contact ball bearing; sufficient cooling to improve the filtration accuracy; improve the feed resolution of the precision feeding system, reduce the feed inertia; reasonable grinding The super-processing parameters and processing flow are factors that cannot be ignored. The grinding allowance is small, the geometrical tolerance is strict, the outer diameter of the small and medium-sized ball bearings should not be super-finished, and the coarse grinding should not be separated to ensure a good surface. quality.
The mounting method of the INA bearing varies depending on the bearing structure, fit, and conditions. Generally, since the shaft is mostly rotated, the inner ring needs an interference fit. Cylindrical bore bearings, press with a press, or use a hot charging method. For taper holes, mount directly on the taper shaft or with a sleeve.
When installed in the outer casing, there is usually a lot of clearance and the outer ring has an interference. It is usually pressed by a press or there is a cold shrink fit method after cooling. When dry ice is used as the coolant and the shrinkage is installed, the moisture in the air will condense on the surface of the angular contact bearing. Therefore, appropriate rust prevention measures are required.
About Us
星期六
Advantages of rolling bearings compared to plain bearings
Rolling bearings have the following advantages over plain bearings:
1. The friction coefficient of the rolling bearing is smaller than that of the sliding bearing, and the transmission efficiency is high. Generally, the friction coefficient of a sliding bearing is 0.08-0.12, and the friction coefficient of a rolling bearing is only 0.001-0.005;
2. Rolling bearings have been standardized, serialized and generalized, suitable for mass production and supply, and easy to use and maintain;
3. The rolling bearing is made of bearing steel and is heat treated. Therefore, the rolling bearing not only has high mechanical properties and long service life, but also can save the expensive expensive non-ferrous metal used for manufacturing the sliding bearing;
4. The internal clearance of the rolling bearing is small, and the machining accuracy of each part is high, so the running accuracy is high. At the same time, the rigidity of the bearing can be increased by a preloading method. This is very important for precision machinery;
5. Some rolling bearings can withstand both radial and axial loads, thus simplifying the structure of the bearing support;
6. Because the rolling bearing has high transmission efficiency and less heat generation, it can reduce the consumption of lubricating oil, and the lubrication maintenance is more trouble-free;
7. Rolling bearings can be easily applied to uranium in any orientation in space.
However, everything is divided into two, rolling bearings also have certain shortcomings, mainly:
1. The ability of a rolling bearing to withstand a load is much smaller than that of a plain bearing of the same volume, and therefore the radial dimension of the rolling bearing is large. Therefore, in the case of heavy load and where the radial size is small and the structural requirements are compact (such as crankshaft bearings for internal combustion engines), sliding bearings are often used;
2. The rolling bearing has large vibration and noise, especially in the later stage of use. Therefore, in the case where the precision is high and vibration is not allowed, the rolling bearing is difficult to perform, and the sliding bearing is generally better.
3. Rolling bearings are particularly sensitive to foreign objects such as metal chips. Once foreign matter enters the bearing, intermittent vibration and noise will occur, which will cause early damage. In addition, rolling bearings are prone to early damage due to metal clip impurities. Even if early damage does not occur, the life of the rolling bearing has a certain limit. In short, the life of a rolling bearing is shorter than that of a plain bearing.
However, compared with sliding bearings, rolling bearings have their own advantages and disadvantages, each of which occupies a certain application. Therefore, the two cannot be completely replaced with each other, and each develops in a certain direction to expand its field. However, due to the outstanding advantages of rolling bearings, there is a tendency for latecomers to stay. At present, rolling bearings have developed into the main support type of machinery, and the application is becoming more and more extensive.
1. The friction coefficient of the rolling bearing is smaller than that of the sliding bearing, and the transmission efficiency is high. Generally, the friction coefficient of a sliding bearing is 0.08-0.12, and the friction coefficient of a rolling bearing is only 0.001-0.005;
2. Rolling bearings have been standardized, serialized and generalized, suitable for mass production and supply, and easy to use and maintain;
3. The rolling bearing is made of bearing steel and is heat treated. Therefore, the rolling bearing not only has high mechanical properties and long service life, but also can save the expensive expensive non-ferrous metal used for manufacturing the sliding bearing;
4. The internal clearance of the rolling bearing is small, and the machining accuracy of each part is high, so the running accuracy is high. At the same time, the rigidity of the bearing can be increased by a preloading method. This is very important for precision machinery;
5. Some rolling bearings can withstand both radial and axial loads, thus simplifying the structure of the bearing support;
6. Because the rolling bearing has high transmission efficiency and less heat generation, it can reduce the consumption of lubricating oil, and the lubrication maintenance is more trouble-free;
7. Rolling bearings can be easily applied to uranium in any orientation in space.
However, everything is divided into two, rolling bearings also have certain shortcomings, mainly:
1. The ability of a rolling bearing to withstand a load is much smaller than that of a plain bearing of the same volume, and therefore the radial dimension of the rolling bearing is large. Therefore, in the case of heavy load and where the radial size is small and the structural requirements are compact (such as crankshaft bearings for internal combustion engines), sliding bearings are often used;
2. The rolling bearing has large vibration and noise, especially in the later stage of use. Therefore, in the case where the precision is high and vibration is not allowed, the rolling bearing is difficult to perform, and the sliding bearing is generally better.
3. Rolling bearings are particularly sensitive to foreign objects such as metal chips. Once foreign matter enters the bearing, intermittent vibration and noise will occur, which will cause early damage. In addition, rolling bearings are prone to early damage due to metal clip impurities. Even if early damage does not occur, the life of the rolling bearing has a certain limit. In short, the life of a rolling bearing is shorter than that of a plain bearing.
However, compared with sliding bearings, rolling bearings have their own advantages and disadvantages, each of which occupies a certain application. Therefore, the two cannot be completely replaced with each other, and each develops in a certain direction to expand its field. However, due to the outstanding advantages of rolling bearings, there is a tendency for latecomers to stay. At present, rolling bearings have developed into the main support type of machinery, and the application is becoming more and more extensive.
星期五
KOYO bearing brand introduction
KOYO SEIKO CO.LTD was established in 1921. KOYO has 8 factories, 6 sales companies and 6 group companies in China. It has 24 sales branches and 26 factories abroad. Three technology research centers have been established all over the world, and the network is spread all over the world. KOYO Bearing provides the fastest service and the most dependable products to the world.
Japan Koyo Seiko Co., Ltd. KOYO Bearing is a world-class bearing manufacturer with a long history and culture and ranked third in Japan. Value & Technology will give you the technology of multiplying the value.
KOYO Bearing Co., Ltd. is a research and development-oriented integrated functional product manufacturing company. Through the manufacture of automotive bearings, steering gear and its components, KOYO Bearing Co., Ltd. is committed to contributing to the perfect coordination of human beings, the earth, society and automobiles.
Japan Koyo Seiko Co., Ltd. KOYO Bearing is a world-class bearing manufacturer with a long history and culture and ranked third in Japan. Value & Technology will give you the technology of multiplying the value.
KOYO Bearing Co., Ltd. is a research and development-oriented integrated functional product manufacturing company. Through the manufacture of automotive bearings, steering gear and its components, KOYO Bearing Co., Ltd. is committed to contributing to the perfect coordination of human beings, the earth, society and automobiles.
星期三
Design of stainless steel deep groove ball bearings
Bearing with dust cover
The bearing with dust cover is suffixed with 2Z and the dust cover is made of stainless steel. The shoulder of the dust-proof cover inner ring forms a very narrow gap and can withstand high temperatures and high rotational speeds. Bearings with dust caps are mainly used in the rotating condition of the inner ring. If the outer ring rotates, the bearing will run at high speed, which will cause grease to leak.
Bearing with seal
Bearings with contact seals, suffixed 2RS1, are made of oil-resistant and wear-resistant nitrile rubber with a steel frame. This allows the seal to operate at temperatures from -40 to +100 ° C and up to +120 ° C in a short time. The sealing lip of the contact seal seals the shoulder of the inner ring. The outer edge of the seal ring is in the groove of the outer ring, which provides a good sealing effect at this position.
When the sealed bearing is operated under certain extreme conditions, such as extremely high speed or high temperature, it may cause leakage of grease between the inner ring and the seal. If the leak condition has a damaging effect on the bearing configuration, special design steps must be taken.
The bearing with dust cover is suffixed with 2Z and the dust cover is made of stainless steel. The shoulder of the dust-proof cover inner ring forms a very narrow gap and can withstand high temperatures and high rotational speeds. Bearings with dust caps are mainly used in the rotating condition of the inner ring. If the outer ring rotates, the bearing will run at high speed, which will cause grease to leak.
Bearing with seal
Bearings with contact seals, suffixed 2RS1, are made of oil-resistant and wear-resistant nitrile rubber with a steel frame. This allows the seal to operate at temperatures from -40 to +100 ° C and up to +120 ° C in a short time. The sealing lip of the contact seal seals the shoulder of the inner ring. The outer edge of the seal ring is in the groove of the outer ring, which provides a good sealing effect at this position.
When the sealed bearing is operated under certain extreme conditions, such as extremely high speed or high temperature, it may cause leakage of grease between the inner ring and the seal. If the leak condition has a damaging effect on the bearing configuration, special design steps must be taken.
Static seals and sealing conditions of SKF imported bearings
SKF imported bearing tightness test is often an assessment of the assembly and working reliability of the assembled cylinder seal and its joints, such as the sealing and connection of the cylinder port, the cylinder piston (with the rod cavity and the rodless cavity) , static seals and sealing conditions. Because the test pressure is very large, especially for the pressure test of the rodless cavity, if there is no tooling to withstand the pressure exerted by the piston without the rod cavity and exert a large pressure on the piston rod through the piston, it is absolutely impossible to bear by the connection of the cylinder port. of. Therefore, for such pressure test, after carefully assembling the oil cylinder, it is carried out in the commissioning stage of the final assembly machine.
The frame of the machine to which the cylinder belongs is subjected to a large pressure. If there is no problem in the assembly of the cylinder, the cylinder will be smooth in the final assembly pressure test, which not only saves the tooling that is separately tested after the cylinder is assembled, but also saves the corresponding working hours, and also shortens the production cycle. Favorable; if there is a problem in the assembly of the cylinder, it will be exposed during the assembly and commissioning. It will be unloaded to disassemble the new assembly, but it will take time and labor to affect the production progress, which is not worth the loss. This is often the result of the operator's inability to carefully examine and work hard.
Therefore, before assembling SKF bearings, it is necessary to carefully check whether the dimensional accuracy of the relevant parts conforms to the drawings. The failure of the sealing parts is often caused by the dimensional accuracy of the sealing groove or the roughness of the sealing surface is not up to the requirement, and secondly to the sealing parts. The geometry should be carefully examined, especially for the inspection of the sealing lip. Seals with irregular shapes, lack of meat, micro cracks, etc., cannot be placed in the product.
In addition, the material and hardness of SKF imported bearing seals should be checked against the product certificate and delivery list. For example, the O-ring has four pressure levels from I to 1 to I and four, and its bearing capacity is also different from low to high. Especially for those who have no experience, the seal of the same specification is often from the outside. It is difficult to distinguish. If the low-pressure sealing ring is accidentally installed in the high-pressure part, it is thought that there will be no problem in the assembly process. As a result, the sealing member is easily broken down during the test or work, resulting in seal failure or a significant shortened service life, and its influence and loss can be imagined. And know.
The frame of the machine to which the cylinder belongs is subjected to a large pressure. If there is no problem in the assembly of the cylinder, the cylinder will be smooth in the final assembly pressure test, which not only saves the tooling that is separately tested after the cylinder is assembled, but also saves the corresponding working hours, and also shortens the production cycle. Favorable; if there is a problem in the assembly of the cylinder, it will be exposed during the assembly and commissioning. It will be unloaded to disassemble the new assembly, but it will take time and labor to affect the production progress, which is not worth the loss. This is often the result of the operator's inability to carefully examine and work hard.
Therefore, before assembling SKF bearings, it is necessary to carefully check whether the dimensional accuracy of the relevant parts conforms to the drawings. The failure of the sealing parts is often caused by the dimensional accuracy of the sealing groove or the roughness of the sealing surface is not up to the requirement, and secondly to the sealing parts. The geometry should be carefully examined, especially for the inspection of the sealing lip. Seals with irregular shapes, lack of meat, micro cracks, etc., cannot be placed in the product.
In addition, the material and hardness of SKF imported bearing seals should be checked against the product certificate and delivery list. For example, the O-ring has four pressure levels from I to 1 to I and four, and its bearing capacity is also different from low to high. Especially for those who have no experience, the seal of the same specification is often from the outside. It is difficult to distinguish. If the low-pressure sealing ring is accidentally installed in the high-pressure part, it is thought that there will be no problem in the assembly process. As a result, the sealing member is easily broken down during the test or work, resulting in seal failure or a significant shortened service life, and its influence and loss can be imagined. And know.
星期二
Bearing vibration and temperature check
1, the vibration of the bearing
Bearing vibration is very sensitive to bearing damage. For example, peeling, indentation, rust, crack, wear, etc. are reflected in the bearing vibration measurement. Therefore, vibration can be measured by using a special bearing vibration measuring device (frequency analyzer, etc.). The size of the frequency can not be inferred from the specific circumstances of the abnormality. The measured value differs depending on the conditions of use of the bearing or the position at which the sensor is mounted. Therefore, it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
2, the temperature of the bearing
The temperature of the bearing, generally the temperature outside the bearing can be inferred. If the oil hole can directly measure the temperature of the bearing outer ring, it is more suitable.
Usually, the temperature of the bearing rises slowly as the bearing starts to run, and reaches a steady state after 1-2 hours. The normal temperature of the bearing varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubrication and installation parts are suitable, the bearing temperature will rise sharply and abnormal temperature will occur. At this time, it is necessary to stop the operation and take necessary precautions.
The thermal sensor can be used to monitor the operating temperature of the bearing at any time, and automatically alarm or stop the occurrence of a burning shaft accident when the temperature exceeds the specified value.
The high temperature often indicates that the bearing is in an abnormal condition. High temperatures are also harmful to the lubricant of the bearing. Sometimes the bearing overheating can be attributed to the lubricant of the bearing. Long-term continuous rotation of the bearing at temperatures above 125 °C will reduce bearing life. Causes of high temperature bearings include: insufficient lubrication or excessive lubrication, lubricants. Contains impurities, excessive load, bearing damage, insufficient clearance, and high friction caused by oil seals.
Therefore, it is necessary to continuously monitor the bearing temperature, whether it is measuring the bearing itself or other important parts. If the operating conditions are the same, any temperature change can indicate that a fault has occurred.
The periodic measurement of the bearing temperature can be carried out by means of a thermometer, such as a skf digital thermometer, which accurately measures the bearing temperature and displays it in °C or Fahrenheit.
The importance of the bearing means that when it is damaged, it will cause the equipment to stop. Therefore, it is better to install a temperature detector for this type of bearing.
Under normal conditions, the bearing will naturally rise in temperature after lubrication or relubrication and last for one or two days.
Bearing vibration is very sensitive to bearing damage. For example, peeling, indentation, rust, crack, wear, etc. are reflected in the bearing vibration measurement. Therefore, vibration can be measured by using a special bearing vibration measuring device (frequency analyzer, etc.). The size of the frequency can not be inferred from the specific circumstances of the abnormality. The measured value differs depending on the conditions of use of the bearing or the position at which the sensor is mounted. Therefore, it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.
2, the temperature of the bearing
The temperature of the bearing, generally the temperature outside the bearing can be inferred. If the oil hole can directly measure the temperature of the bearing outer ring, it is more suitable.
Usually, the temperature of the bearing rises slowly as the bearing starts to run, and reaches a steady state after 1-2 hours. The normal temperature of the bearing varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubrication and installation parts are suitable, the bearing temperature will rise sharply and abnormal temperature will occur. At this time, it is necessary to stop the operation and take necessary precautions.
The thermal sensor can be used to monitor the operating temperature of the bearing at any time, and automatically alarm or stop the occurrence of a burning shaft accident when the temperature exceeds the specified value.
The high temperature often indicates that the bearing is in an abnormal condition. High temperatures are also harmful to the lubricant of the bearing. Sometimes the bearing overheating can be attributed to the lubricant of the bearing. Long-term continuous rotation of the bearing at temperatures above 125 °C will reduce bearing life. Causes of high temperature bearings include: insufficient lubrication or excessive lubrication, lubricants. Contains impurities, excessive load, bearing damage, insufficient clearance, and high friction caused by oil seals.
Therefore, it is necessary to continuously monitor the bearing temperature, whether it is measuring the bearing itself or other important parts. If the operating conditions are the same, any temperature change can indicate that a fault has occurred.
The periodic measurement of the bearing temperature can be carried out by means of a thermometer, such as a skf digital thermometer, which accurately measures the bearing temperature and displays it in °C or Fahrenheit.
The importance of the bearing means that when it is damaged, it will cause the equipment to stop. Therefore, it is better to install a temperature detector for this type of bearing.
Under normal conditions, the bearing will naturally rise in temperature after lubrication or relubrication and last for one or two days.
星期一
Classification of rolling mill bearings
 |
| http://www.bearingkingdom.com |
Rolling mill bearings are used in the rolling industry, ie rolling of non-ferrous metals, ferrous metals and non-metallic products. Used for rolling bearings at the roll diameter and on the drum. Four-row cylindrical roller bearings are usually used to withstand radial loads. Thrust roller or thrust ball bearings and axial angular contact balls or radial roller bearings are subjected to axial loads. Most of them are now oil-air lubricated or oil mist lubricated and greased. Lubricate and cool.
Rolling mill bearing classification
(1) Spherical roller bearings
The configuration of the rolling mill bearings on the rolling mill was different. At that time, two sets of spherical roller bearings were mainly installed side by side on the same roll neck. This configuration basically meets the production conditions at that time, and the rolling speed can reach 600 rpm. However, with the increase of speed, its shortcomings are more and more prominent: short bearing life, large consumption, low precision of finished products, serious wear of the roll neck, large roll yaw, etc.
(2) Four-row cylindrical roller bearing + thrust bearing
The inner diameter of the cylindrical roller bearing is tightly matched with the roll neck to withstand radial force. It has the advantages of large load capacity, high limit speed, high precision, separable inner and outer rings, interchangeable, easy processing, low production cost, convenient installation and disassembly, etc. The thrust bearing is subjected to axial force, and the specific structure type can be selected according to the characteristics of the rolling mill.
At heavy load and low speed, it is equipped with a thrust roller bearing to withstand the thrust load with a small axial clearance. When the rolling speed is high, it is equipped with angular contact ball bearings, which not only has high speed limit, but also can control the axial play during operation. The rolls are tightly axially guided and can withstand typical axial load forces. 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 currently the most widely used, and is widely used in wire rod mills, sheet mills, foil mills, and double support rolls. Support rolls for rolling mill cold rolling mills and hot rolling mills.
(3) Four row tapered roller bearings
Tapered roller bearings can withstand both radial and axial forces without the need for a thrust bearing, making the mainframe even more compact. 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 still widely used, such as rolls for work rolls, blanking machines, steel beam mills, etc. in four-high hot rolling mills and cold rolling mills.
Four-row cylindrical roller bearings and six-row cylindrical roller bearings are almost exclusively used for roll necks, rollers and rolling mills in rolling stands. These bearings have low friction compared to other roller bearings. Since these bearings are usually mounted on the roll neck with an interference fit, they are particularly suitable for rolling mill applications with high rolling speeds. The low cross-section of these bearings allows the use of a relatively large roll neck diameter compared to the roll diameter. Due to the large number of rollers that can be loaded, its radial load capacity is very high.
Multi-row cylindrical roller bearings can only withstand radial loads. Therefore, these bearings are mounted together with deep groove ball bearings or angular contact ball bearings, or tapered roller bearings of radial design or thrust design, which are subjected to axial loads. The four-row and six-row tapered roller bearings are of separate design, that is, the bearing ring with integral flange and the roller and cage assembly can be installed separately from the separate bearing ring, or all bearing components can be installed separately.
This simplifies bearing installation, maintenance and inspection to a considerable extent. The bearing can withstand a certain amount of axial displacement of the shaft relative to the bearing housing. Four-row cylindrical roller bearings have a cylindrical bore and some sizes of bearings are available with tapered bores. Bearings with tapered bores can be adjusted during installation to achieve a certain radial internal clearance or a defined preload.
订阅：
博文 (Atom)