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.
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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
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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.
星期五
How do hub bearings do routine maintenance?
Hub bearing is a summary of how to do daily maintenance: CNC machine tool manufacturing application data management system Autodesk launches the most comprehensive solution for manufacturing customers. Economical CNC system hardware design compound cycle cutting instruction outer diameter roughing compound cycle G71 instruction large space 3D laser scanning system CNC lathe machining spherical error analysis and elimination method Precision punching technology in car production Al-Mg and Al-Cu alloy aluminum arc welding electrode selection How to use the machining center tool length compensation function General machinery industry standard English-Chinese Comparison table (2) Processing center processing standard The first automatic wide-band gear splitting machine in China talk about the choice of inverter capacity The effective method to solve the "bottleneck" of auto parts processing Ten suggestions for CNC tool milling technology High-speed cutting Technical development and prospects CNC machine tool failure analysis Case analysis Experience introduces the processing principle of involute tooth profile Gas cutting Introduction Maintenance Daily how to bearing If checking brake lubrication Rotating tire hub bearing Car important walking machine hub axle bears negative reduction chassis running friction resistance Keep the car normal Failure of the heavy-duty wheel bearing bearing may cause noise to the bearing. Especially the front wheel is more likely to cause the direction to run out of control. The wheel bearing must be maintained on schedule. 1. Wheel bearing inspection and inspection of the hub bearing.
Hub bearings are important moving parts for automobiles. The hub axle bears the burden of reducing the frictional resistance during the operation of the chassis and maintaining the normal driving of the car. If the hub bearing is faulty, it may cause noise, bearing heat, etc., especially the front wheel is more obvious, which may lead to dangerous phenomena such as out of control. Therefore, the hub bearings must be maintained on schedule.
1. Inspection of the hub bearing
(1) When inspecting the tightness of the hub bearing, firstly, the axle of the wheel at one end of the wheel of the vehicle is inspected, and the vehicle is safely framed with a vehicle stool, a wooden cover, and the like.
(2) Turn the number of wheels to be inspected by hand to see if the rotation is stable and there is abnormal noise. If the rotation is not smooth and there is friction, the brake part is not normal; if there is no noise, the rotation is not smooth and it is loose when it is tight, indicating that the bearing part is not normal. The hub should be removed when the above abnormality occurs.
For small cars, when inspecting the hub bearings, hold the upper and lower sides of the tires with both hands, and pull the tires back and forth with both hands and repeat them several times. If it is normal, there should be no feeling of looseness and blockage; if the swing has a feeling of looseness, the hub should be removed.
(3) Inspection of the brakes. Usually when inspecting the hub bearing, check the wheel brake device. If there is oil on the inside of the tire, it may be caused by oil leakage from the brake cylinder or brake hose. The cause should be checked and eliminated.
2. Maintenance of wheel bearing
Before disassembling the hub, prepare the wheel hub for maintenance, stop the car and set up the axle to ensure the safety of the maintenance work.
(1) Remove the decorative cover and dust cover of the hub shaft head;
(2) Remove the tire nut and tire, taking care not to hurt the thread of the tire bolt. If it is a disc brake, remove the brake and use it to remove the lock ring or lock pin.
(3) Remove the hub with a special tool;
(4) Scrape the old grease in the bearing, journal and hub cavity, clean the hub bearing and journal with a cleaning agent and wipe dry with a cloth. Finally, wipe the inner cavity of the hub with a cloth.
(5) Check the hub bearing and the bearing race, and find that there are cracks, fatigue peeling and loose bearing rollers. The bearings should be replaced. If there is a pitting on the bearing race, the bearing should also be replaced.
(6) Check the matching between the inner diameter of the bearing and the journal. The matching clearance should be no more than 0.1Omm. When measuring the journal, it should be measured at the upper and lower parts of the vertical ground (the largest wear part at this place). If the fit clearance exceeds the specified service limit, the bearing should be replaced to restore the normal fit clearance. It is not allowed to burr and pock on the journal to narrow the gap.
(7) After all the parts meet the requirements, apply the grease to the inner bearing and put it in the wheel hub.
(8) When applying grease to the bearing inner cavity, be careful to squeeze the grease into the bearing until the grease emerges from the other side of the bearing. Apply a thin layer of grease to the hub cavity and the shaft cap to prevent rust. Be careful not to apply too much grease in the hub cavity, otherwise it will affect heat dissipation and braking.
(9) Put the hub and outer bearing back on the journal, screw the shaft adjusting nut by hand, and then tighten the adjusting nut with the shaft wrench according to the specified torque. After tightening the nut, turn the hub a few turns to see if the bearing is installed. On the other hand, the bearing and the race are properly matched by rotation. At this time, the bearing tightness is appropriate, and the wheel is free to rotate and the axial gap is not felt.
(10) Finally, the components such as the locking piece, the fixing nut, the tire, the dust cover and the decorative cover are sequentially installed.
(11) After the wheel bearing is adjusted, drive a mileage (about 1Okm), stop the inspection, use it to wipe the temperature of the hub. If it is hot, adjust the bearing too tightly, it should be re-adjusted to properly loosen the bearing tightness.
Hub bearings are important moving parts for automobiles. The hub axle bears the burden of reducing the frictional resistance during the operation of the chassis and maintaining the normal driving of the car. If the hub bearing is faulty, it may cause noise, bearing heat, etc., especially the front wheel is more obvious, which may lead to dangerous phenomena such as out of control. Therefore, the hub bearings must be maintained on schedule.
1. Inspection of the hub bearing
(1) When inspecting the tightness of the hub bearing, firstly, the axle of the wheel at one end of the wheel of the vehicle is inspected, and the vehicle is safely framed with a vehicle stool, a wooden cover, and the like.
(2) Turn the number of wheels to be inspected by hand to see if the rotation is stable and there is abnormal noise. If the rotation is not smooth and there is friction, the brake part is not normal; if there is no noise, the rotation is not smooth and it is loose when it is tight, indicating that the bearing part is not normal. The hub should be removed when the above abnormality occurs.
For small cars, when inspecting the hub bearings, hold the upper and lower sides of the tires with both hands, and pull the tires back and forth with both hands and repeat them several times. If it is normal, there should be no feeling of looseness and blockage; if the swing has a feeling of looseness, the hub should be removed.
(3) Inspection of the brakes. Usually when inspecting the hub bearing, check the wheel brake device. If there is oil on the inside of the tire, it may be caused by oil leakage from the brake cylinder or brake hose. The cause should be checked and eliminated.
2. Maintenance of wheel bearing
Before disassembling the hub, prepare the wheel hub for maintenance, stop the car and set up the axle to ensure the safety of the maintenance work.
(1) Remove the decorative cover and dust cover of the hub shaft head;
(2) Remove the tire nut and tire, taking care not to hurt the thread of the tire bolt. If it is a disc brake, remove the brake and use it to remove the lock ring or lock pin.
(3) Remove the hub with a special tool;
(4) Scrape the old grease in the bearing, journal and hub cavity, clean the hub bearing and journal with a cleaning agent and wipe dry with a cloth. Finally, wipe the inner cavity of the hub with a cloth.
(5) Check the hub bearing and the bearing race, and find that there are cracks, fatigue peeling and loose bearing rollers. The bearings should be replaced. If there is a pitting on the bearing race, the bearing should also be replaced.
(6) Check the matching between the inner diameter of the bearing and the journal. The matching clearance should be no more than 0.1Omm. When measuring the journal, it should be measured at the upper and lower parts of the vertical ground (the largest wear part at this place). If the fit clearance exceeds the specified service limit, the bearing should be replaced to restore the normal fit clearance. It is not allowed to burr and pock on the journal to narrow the gap.
(7) After all the parts meet the requirements, apply the grease to the inner bearing and put it in the wheel hub.
(8) When applying grease to the bearing inner cavity, be careful to squeeze the grease into the bearing until the grease emerges from the other side of the bearing. Apply a thin layer of grease to the hub cavity and the shaft cap to prevent rust. Be careful not to apply too much grease in the hub cavity, otherwise it will affect heat dissipation and braking.
(9) Put the hub and outer bearing back on the journal, screw the shaft adjusting nut by hand, and then tighten the adjusting nut with the shaft wrench according to the specified torque. After tightening the nut, turn the hub a few turns to see if the bearing is installed. On the other hand, the bearing and the race are properly matched by rotation. At this time, the bearing tightness is appropriate, and the wheel is free to rotate and the axial gap is not felt.
(10) Finally, the components such as the locking piece, the fixing nut, the tire, the dust cover and the decorative cover are sequentially installed.
(11) After the wheel bearing is adjusted, drive a mileage (about 1Okm), stop the inspection, use it to wipe the temperature of the hub. If it is hot, adjust the bearing too tightly, it should be re-adjusted to properly loosen the bearing tightness.
星期三
Maintenance of forklift clutch release bearing
Separating bearings of internal combustion forklift clutches work frequently, and the number of damages accounts for a large proportion of common faults in forklift maintenance. According to the analysis, the high temperature of the engine is transmitted to the separation bearing, and the high-speed rotation of the bearing produces high temperature. Under such conditions, the oil is difficult to remain in the bearing, the bearing works continuously under high temperature conditions, and the lubrication condition is not good, which is frequent The cause of the damage.
The engine does not disintegrate the oil filling method. First open the clutch cover to check the wear of the separated bearing. If it is confirmed that the bearing is not damaged or the wear is not over the limit, remove the clutch pedal, adjust the connecting rod pin, and return the separating bearing and its seat back. In the final position, fill the hole in the bearing housing with a grease gun until the bearing overflows. Then turn the bearing slightly, refill the oil, repeat the above work until there is a little butter around the bearing, and then turn the bearing. Observe the amount of oil. If there is resistance to the rotation of the bearing, it is proved that the bearing is filled with butter. Then remove a small amount of butter from the separation housing and reinstall the removed pin and clutch cover.
The engine oil disintegration method disassembles the engine to expose the assembly of the separation bearing and the bearing housing, and uses a grease gun to fill the small oil hole below the inner ring of the separation bearing housing. When the bearing has a butter overflow, the bearing is rotated until the bearing has a ring. The butter can overflow.
The engine does not disintegrate the oil filling method. First open the clutch cover to check the wear of the separated bearing. If it is confirmed that the bearing is not damaged or the wear is not over the limit, remove the clutch pedal, adjust the connecting rod pin, and return the separating bearing and its seat back. In the final position, fill the hole in the bearing housing with a grease gun until the bearing overflows. Then turn the bearing slightly, refill the oil, repeat the above work until there is a little butter around the bearing, and then turn the bearing. Observe the amount of oil. If there is resistance to the rotation of the bearing, it is proved that the bearing is filled with butter. Then remove a small amount of butter from the separation housing and reinstall the removed pin and clutch cover.
The engine oil disintegration method disassembles the engine to expose the assembly of the separation bearing and the bearing housing, and uses a grease gun to fill the small oil hole below the inner ring of the separation bearing housing. When the bearing has a butter overflow, the bearing is rotated until the bearing has a ring. The butter can overflow.
星期一
Influence of machining allowance of cylindrical roller bearing outer diameter on grinding process
In the process of machining the outer diameter of cylindrical roller bearings, it is necessary to pay attention to the problem of retention and to understand the influence of the amount of grinding on the grinding process. From the perspective of impact, the future construction objectives and construction methods can be continuously improved. effect.
1. Process analysis of bearing outer ring
The machining process refers to the operation of the reference process, and the size, geometry, nature and relative position of the production object are changed in a specific way to obtain a semi-finished product or a semi-finished product. The process flow is the process, which is related to factors such as equipment conditions, product quantity, and artificial quality.
The process of machining processes is rich in content, such as raw material storage, blank manufacturing, and heat-treated parts. The process is mainly carried out in a sequence of processes. Single-piece production, mass production, and mass production are the main types of production.
1.1 anti-outer ring channel edge convex method
The outer channel of the self-aligning ball bearing is spherical, but the raceway is raised at point A. This kind of protrusion will affect the self-aligning performance of the self-aligning ball bearing, and even cannot be self-aligning, and there is a convex side on the bearing. When rotating, it will generate frictional resistance to the steel ball, which will accelerate the wear of the steel ball and reduce the service life.
The reason for this phenomenon is that the thickness of the grinding wheel is small and the grinding wheel consumes quickly at the edge of the groove. The outer ring of the self-aligning bearing of the branch is a grooved machining groove, such as 3MZ1410SA. If the thickness of the grinding wheel is smaller than the width of the outer ring, the edge of the groove will not be ground and the protrusion will be formed. In order to eliminate this defect, a grinding wheel having a thickness greater than the outer ring width of 1 to 1.5 mm may be selected.
Because the edge of the outer ring of the bearing is very sharp, and the grinding wheel consumes very fast in the process, if the processing personnel do not adjust it properly in time, it is difficult to ensure that the entire outer ring can be evenly ground. The plane is prone to high and low unevenness, which seriously affects the quality of the product. Therefore, in order to solve this problem better, the processing personnel can adjust the number of dressings appropriately, and increase the compensation amount of the dresser, so as to ensure that the blunt grinding wheel can also get a lot of corrections. In addition, due to the different processing requirements of rough grinding and fine grinding, there are also large differences in the choice of grinding wheel size. Therefore, the processing personnel must select the grinding wheel with the appropriate particle size after the final confirmation of the grinding method, so as to avoid the uneven quality of the outer ring edge of the self-aligning ball bearing.
1.2 Method for reducing the position error of the outer groove spherical surface
The position of the center of the spherical surface may not completely coincide with the position of the theoretical center, and there may be some errors. This is completely controlled by the detection method of the difference in the width of the outer ring to control the outer ring on the M7675B double end grinding machine. The mutual difference can be controlled to be small. Within the range (within 0.015mm). The center position of the outer ring sphere has been measured by the position template. The sample is divided into the maximum limit size and the minimum limit size. When the outer channel is measured on the side of the maximum limit position of the spherical position template, there is a "light gap" near the inner side of the template. There is a "light gap" on the outside. This measurement is completely dependent on visual inspection and the error is large. In order to reduce the error, the instrument is measured by D923 inner diameter measuring instrument. The height of the measuring point is generally h=3mm (the smaller the chamfering size h is, the better). When measuring, the two sides are measured. By adjusting the feeding position of the grinding wheel, both sides The closer the measurement results are, the more symmetrical the two sides of the spherical surface are, that is, the center position of the spherical surface is close to the theoretical center position. If the difference between the outer ring widths is considered, the error can be basically controlled to about 0.015 mm. By changing to the instrument measurement, the error of the center position of the spherical surface can be controlled within a relatively ideal range.
1.3 Method for guaranteeing the radius of curvature of the spherical surface
It is well known that the outer ring channel of the self-aligning ball is a circular arc-shaped spherical surface. The most fundamental purpose of this design is to ensure that the inner ring of the bearing can produce better alignment on the outer ring, although this is a basic The concept of design theory, but in the actual processing and production, there is still a certain error. Among them, poor pairing is one of the most common problems. Most of the processing personnel use the measurement method of the pistol watch when measuring the diagonal difference. The main working principle is to keep the pistol table in motion, the outer ring swing measurement, and the diagonal difference is strict. Control is within reasonable limits. At the same time, in order to control the error within the minimum technical requirements, it is necessary to ensure the consistency of the spherical curvature. Every time before the product is processed, the grinding wheel can be fully repaired, and the grinding wheel dresser is not guaranteed as much as possible during the processing. Make adjustments to improve the processing efficiency and quality of the product.
1. Process analysis of bearing outer ring
The machining process refers to the operation of the reference process, and the size, geometry, nature and relative position of the production object are changed in a specific way to obtain a semi-finished product or a semi-finished product. The process flow is the process, which is related to factors such as equipment conditions, product quantity, and artificial quality.
The process of machining processes is rich in content, such as raw material storage, blank manufacturing, and heat-treated parts. The process is mainly carried out in a sequence of processes. Single-piece production, mass production, and mass production are the main types of production.
1.1 anti-outer ring channel edge convex method
The outer channel of the self-aligning ball bearing is spherical, but the raceway is raised at point A. This kind of protrusion will affect the self-aligning performance of the self-aligning ball bearing, and even cannot be self-aligning, and there is a convex side on the bearing. When rotating, it will generate frictional resistance to the steel ball, which will accelerate the wear of the steel ball and reduce the service life.
The reason for this phenomenon is that the thickness of the grinding wheel is small and the grinding wheel consumes quickly at the edge of the groove. The outer ring of the self-aligning bearing of the branch is a grooved machining groove, such as 3MZ1410SA. If the thickness of the grinding wheel is smaller than the width of the outer ring, the edge of the groove will not be ground and the protrusion will be formed. In order to eliminate this defect, a grinding wheel having a thickness greater than the outer ring width of 1 to 1.5 mm may be selected.
Because the edge of the outer ring of the bearing is very sharp, and the grinding wheel consumes very fast in the process, if the processing personnel do not adjust it properly in time, it is difficult to ensure that the entire outer ring can be evenly ground. The plane is prone to high and low unevenness, which seriously affects the quality of the product. Therefore, in order to solve this problem better, the processing personnel can adjust the number of dressings appropriately, and increase the compensation amount of the dresser, so as to ensure that the blunt grinding wheel can also get a lot of corrections. In addition, due to the different processing requirements of rough grinding and fine grinding, there are also large differences in the choice of grinding wheel size. Therefore, the processing personnel must select the grinding wheel with the appropriate particle size after the final confirmation of the grinding method, so as to avoid the uneven quality of the outer ring edge of the self-aligning ball bearing.
1.2 Method for reducing the position error of the outer groove spherical surface
The position of the center of the spherical surface may not completely coincide with the position of the theoretical center, and there may be some errors. This is completely controlled by the detection method of the difference in the width of the outer ring to control the outer ring on the M7675B double end grinding machine. The mutual difference can be controlled to be small. Within the range (within 0.015mm). The center position of the outer ring sphere has been measured by the position template. The sample is divided into the maximum limit size and the minimum limit size. When the outer channel is measured on the side of the maximum limit position of the spherical position template, there is a "light gap" near the inner side of the template. There is a "light gap" on the outside. This measurement is completely dependent on visual inspection and the error is large. In order to reduce the error, the instrument is measured by D923 inner diameter measuring instrument. The height of the measuring point is generally h=3mm (the smaller the chamfering size h is, the better). When measuring, the two sides are measured. By adjusting the feeding position of the grinding wheel, both sides The closer the measurement results are, the more symmetrical the two sides of the spherical surface are, that is, the center position of the spherical surface is close to the theoretical center position. If the difference between the outer ring widths is considered, the error can be basically controlled to about 0.015 mm. By changing to the instrument measurement, the error of the center position of the spherical surface can be controlled within a relatively ideal range.
1.3 Method for guaranteeing the radius of curvature of the spherical surface
It is well known that the outer ring channel of the self-aligning ball is a circular arc-shaped spherical surface. The most fundamental purpose of this design is to ensure that the inner ring of the bearing can produce better alignment on the outer ring, although this is a basic The concept of design theory, but in the actual processing and production, there is still a certain error. Among them, poor pairing is one of the most common problems. Most of the processing personnel use the measurement method of the pistol watch when measuring the diagonal difference. The main working principle is to keep the pistol table in motion, the outer ring swing measurement, and the diagonal difference is strict. Control is within reasonable limits. At the same time, in order to control the error within the minimum technical requirements, it is necessary to ensure the consistency of the spherical curvature. Every time before the product is processed, the grinding wheel can be fully repaired, and the grinding wheel dresser is not guaranteed as much as possible during the processing. Make adjustments to improve the processing efficiency and quality of the product.
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