The influence of the metallurgical quality of the outer spherical bearing material is the main factor in the early failure of the rolling bearing. With the advancement of metallurgical technology (such as bearing steel, vacuum degassing, etc.), the quality of raw materials has been improved. The proportion of raw material quality factors in bearing failure analysis has dropped significantly, but it is still one of the main factors of bearing failure. The choice of proper or not is still a bearing failure analysis that must be considered.
The main task of the failure analysis of the outer spherical bearing housing is based on a large number of background materials, data and failure mode analysis to find out the main factors causing bearing failure. In order to achieve targeted improvement, the service life of the bearing is extended to avoid bearing protrusion. The early event of the incident failed.
The fatigue life of the outer spherical bearing seat calculated according to the prescribed formula and calculation rules is calculated as the fatigue life. The calculated total rotation value is defined as the total rotation value when the inner ring or the shaft ring rotates (when the outer ring or the seat ring is fixed).
According to the specified standard test method, the rolling bearing fatigue life test procedure, in the performance of the test machine can meet the requirements of a method, the sampling fatigue life test of a batch of bearings, the actual test life obtained from the test data processing It is the fatigue test life of the batch of outer spherical bearing housings represented by the tested bearings.
The rolling bearing fatigue life test is an intensive fatigue life test method that uses sufficient lubrication to minimize the wear factor of the rolling bearing and uses the enhanced load and speed to highlight the bearing fatigue factor.
The calculation method of the fatigue life of the outer spherical bearing housing and the fatigue life test are complementary, and the results obtained by the two have sufficient correspondence.
However, in reality, for each specific use case, a sufficient number of bearings are taken for life testing to verify that the selected bearing is suitable, which is very economical, time-consuming and labor-intensive, so The test method for the life of a spherical bearing is only used when it is necessary or important. In most cases, the standard life calculation method is used to estimate the service life of the bearing, which has a sufficient degree of dependence.
2018年12月18日星期二
What are the tests of KOYO bearings?
There are many types of KOYO bearing tests:
According to the KOYO bearing test site, it can be divided into field test and laboratory test;
According to the KOYO bearing reliability planning stage, it can be divided into developmental test, special test, appraisal test (inspection test) and acceptance test;
According to the load applied by KOYO bearing test, it can be divided into constant load test, accelerated life test and variable load test;
According to the KOYO bearing test content can be divided into bearing performance test, bearing life test, bearing reliability test, bearing environmental test;
According to the sample capacity of the test KOYO bearing, it can be divided into complete test, incomplete test, sequential test and sampling test; incomplete test can be subdivided into timed censoring test, fixed censoring test, group elimination test or violent death test;
According to the test speed of KOYO bearing, it can be divided into normal speed test of bearing, high speed (low speed) test and limit speed test.
According to the KOYO bearing test site, it can be divided into field test and laboratory test;
According to the KOYO bearing reliability planning stage, it can be divided into developmental test, special test, appraisal test (inspection test) and acceptance test;
According to the load applied by KOYO bearing test, it can be divided into constant load test, accelerated life test and variable load test;
According to the KOYO bearing test content can be divided into bearing performance test, bearing life test, bearing reliability test, bearing environmental test;
According to the sample capacity of the test KOYO bearing, it can be divided into complete test, incomplete test, sequential test and sampling test; incomplete test can be subdivided into timed censoring test, fixed censoring test, group elimination test or violent death test;
According to the test speed of KOYO bearing, it can be divided into normal speed test of bearing, high speed (low speed) test and limit speed test.
2018年12月14日星期五
NTN cylindrical roller bearing use precautions on life impact
NTN cylindrical roller bearing are precision components that need to be handled with care. No matter how high-performance cylindrical roller bearings are used, the expected high performance will not be achieved if used improperly. The following are some precautions for the use of bearings.
First, keep the bearing and its surroundings clean
Even small dust that is invisible to the naked eye enters the NTN bearing, which increases bearing wear, vibration and noise. Cylindrical roller bearings and their surrounding accessories should be kept clean, especially dust and dirt, and the tools and working environment must be kept clean.
Second, use the installation carefully
It is not allowed to punch strongly. It is not allowed to directly hit the bearing with a hammer. It is not allowed to transmit pressure through the rolling elements.
Third, use the appropriate and correct installation tools
Whenever possible, use special tools, such as special heaters and puller tools, to avoid using cloth and staple fibers.
Fourth, to prevent bearing corrosion
When taking the bearing directly by hand, be sure to wash off the sweat from your hands and apply high-quality mineral oil before handling. Pay special attention to rust prevention during the rainy season and summer. However, under some special operating conditions, cylindrical roller bearings can achieve longer life than conventional calculations, especially at light loads. These special operating preconditions are when the rolling surfaces (tracks and rolling elements) are effectively separated by a lubricant film and the surface damage caused by contaminants is limited. In fact, under ideal conditions, the so-called permanent bearing life is possible.
There are many factors that affect the service life of NTN bearings, which can be roughly divided into usage factors and internal factors.
The use factors mainly refer to whether the installation adjustment, use and maintenance, maintenance and repair, etc. meet the technical requirements. The installation condition is one of the primary factors in the use factor, and the force state between the parts of the entire cylindrical roller bearing changes due to improper installation, and the NTN bearing operates in an abnormal state and ends the service life early. The internal factors mainly refer to the three major factors that determine the quality of the bearing, such as structural design, manufacturing process and material quality.
The manufacture of bearings generally involves multiple processing steps. The rationality, advancement and stability of each processing technology will also affect the life of the bearing. The heat treatment and grinding process that affects the quality of the finished cylindrical roller bearing has a more direct relationship with the failure of the NTN bearing.
First, keep the bearing and its surroundings clean
Even small dust that is invisible to the naked eye enters the NTN bearing, which increases bearing wear, vibration and noise. Cylindrical roller bearings and their surrounding accessories should be kept clean, especially dust and dirt, and the tools and working environment must be kept clean.
Second, use the installation carefully
It is not allowed to punch strongly. It is not allowed to directly hit the bearing with a hammer. It is not allowed to transmit pressure through the rolling elements.
Third, use the appropriate and correct installation tools
Whenever possible, use special tools, such as special heaters and puller tools, to avoid using cloth and staple fibers.
Fourth, to prevent bearing corrosion
When taking the bearing directly by hand, be sure to wash off the sweat from your hands and apply high-quality mineral oil before handling. Pay special attention to rust prevention during the rainy season and summer. However, under some special operating conditions, cylindrical roller bearings can achieve longer life than conventional calculations, especially at light loads. These special operating preconditions are when the rolling surfaces (tracks and rolling elements) are effectively separated by a lubricant film and the surface damage caused by contaminants is limited. In fact, under ideal conditions, the so-called permanent bearing life is possible.
There are many factors that affect the service life of NTN bearings, which can be roughly divided into usage factors and internal factors.
The use factors mainly refer to whether the installation adjustment, use and maintenance, maintenance and repair, etc. meet the technical requirements. The installation condition is one of the primary factors in the use factor, and the force state between the parts of the entire cylindrical roller bearing changes due to improper installation, and the NTN bearing operates in an abnormal state and ends the service life early. The internal factors mainly refer to the three major factors that determine the quality of the bearing, such as structural design, manufacturing process and material quality.
The manufacture of bearings generally involves multiple processing steps. The rationality, advancement and stability of each processing technology will also affect the life of the bearing. The heat treatment and grinding process that affects the quality of the finished cylindrical roller bearing has a more direct relationship with the failure of the NTN bearing.
2018年12月12日星期三
How to do regular maintenance after rolling bearing installation
Commonly used installation tools for rolling bearings are hand hammers, copper rods, sleeves, special pads, screw-mosquito fixtures, presses, etc. The amount has vernier calipers, micrometers, dial gauges, etc., but different tools should be selected according to different bearing models.
After selecting the correct tool, the bearing can be installed. Pay attention to the presence of no bumps, rust layer, wear debris, sand, dust and dirt. If it is, it will cause installation difficulties and must be kept imported. The surface of the bearing assembly and the mating parts are clean.
In addition to the surface of the rolling bearing assembly and the matching of the surface of the part to be cleaned, pay attention to the rust layer of the journal, the surface of the housing hole, the shoulder end face, and the connecting parts such as bushings, washers, and end caps. If you have one, you can use a fine cloth, light sanding, and then install.
1. In terms of bearing speed, the bearing is determined according to the type, size, accuracy, cage type, load, lubrication method, and cooling method of the bearing.
2. The installation and disassembly of the bearing need to be disassembled and installed frequently in specific applications to ensure that it can be inspected and repaired according to its location. Bearings that can be installed separately for the inner and outer rings, such as cylindrical bearings, needle bearings, and tapered bearings, are well suited for this application. The tapered self-aligning ball bearing and self-aligning roller bearing also simplify the installation procedure with the help of the bushing.
3. In some cases, the rolling bearing should be pre-stressed to increase the rigidity. This procedure is usually used for deep groove ball bearings, radial thrust ball bearings and tapered roller bearing inner and outer ring offsets, shaft bending, shaft or bearing housing tolerance changes. Mismatching will lead to eccentricity of the inner and outer rings. In order to prevent the eccentric angle from being too large, automatic self-aligning ball bearings, self-aligning roller bearings, or self-aligning bearing seats are preferred choices.嗓 Audio frequency and torque, dynamic bearings are produced according to high-precision scale, so the sound and torque are small. Deep groove ball bearings and cylindrical roller bearings are used in combination for low noise and low torque.
After selecting the correct tool, the bearing can be installed. Pay attention to the presence of no bumps, rust layer, wear debris, sand, dust and dirt. If it is, it will cause installation difficulties and must be kept imported. The surface of the bearing assembly and the mating parts are clean.
In addition to the surface of the rolling bearing assembly and the matching of the surface of the part to be cleaned, pay attention to the rust layer of the journal, the surface of the housing hole, the shoulder end face, and the connecting parts such as bushings, washers, and end caps. If you have one, you can use a fine cloth, light sanding, and then install.
1. In terms of bearing speed, the bearing is determined according to the type, size, accuracy, cage type, load, lubrication method, and cooling method of the bearing.
2. The installation and disassembly of the bearing need to be disassembled and installed frequently in specific applications to ensure that it can be inspected and repaired according to its location. Bearings that can be installed separately for the inner and outer rings, such as cylindrical bearings, needle bearings, and tapered bearings, are well suited for this application. The tapered self-aligning ball bearing and self-aligning roller bearing also simplify the installation procedure with the help of the bushing.
3. In some cases, the rolling bearing should be pre-stressed to increase the rigidity. This procedure is usually used for deep groove ball bearings, radial thrust ball bearings and tapered roller bearing inner and outer ring offsets, shaft bending, shaft or bearing housing tolerance changes. Mismatching will lead to eccentricity of the inner and outer rings. In order to prevent the eccentric angle from being too large, automatic self-aligning ball bearings, self-aligning roller bearings, or self-aligning bearing seats are preferred choices.嗓 Audio frequency and torque, dynamic bearings are produced according to high-precision scale, so the sound and torque are small. Deep groove ball bearings and cylindrical roller bearings are used in combination for low noise and low torque.
2018年12月8日星期六
Production characteristics of FAG deep groove ball bearing parts
Compared with general mechanical parts, FAG bearing parts are short and thin rotary surface bodies. The rotary body determines that the machining machine tools are relatively simple, most of them are lathes and grinding machines; short and thin determines the axial stiffness and axial direction. The deformation is negligible, the radial stiffness is poor, and the tightening method during processing requires special consideration.
Although the deep groove ball bearing parts have a simple structure but high technical requirements, they have the following processing characteristics:
Precision machining
Most of the surface of FAG bearing parts is ground, and the grinding size and geometric accuracy are in μm. In particular, the raceways and rolling elements of the ferrule are more precise and require super finishing or grinding.
2. Multi-process processing
FAG bearing parts have high requirements and production processes are inevitable. General bearing production requires 20 to 40 processes, and more than 70.
3. Forming processing
The working surfaces of the bearing parts are all rotary forming surfaces, which are suitable for processing by molding. For example, the forging press and the grinding of the ferrule raceway are processed by forming tools or anti-profile plates.
In addition, most of the bearings are standardized products. The bearings of the same type require a large amount. In order to improve productivity, reduce costs, ensure quality, and widely adopt new technologies and improve mechanization and automation, deep groove ball bearings are generally FAG. Bearing models and varieties are produced in large quantities, and even special automatic lines or assembly lines can be established for production
Although the deep groove ball bearing parts have a simple structure but high technical requirements, they have the following processing characteristics:
Precision machining
Most of the surface of FAG bearing parts is ground, and the grinding size and geometric accuracy are in μm. In particular, the raceways and rolling elements of the ferrule are more precise and require super finishing or grinding.
2. Multi-process processing
FAG bearing parts have high requirements and production processes are inevitable. General bearing production requires 20 to 40 processes, and more than 70.
3. Forming processing
The working surfaces of the bearing parts are all rotary forming surfaces, which are suitable for processing by molding. For example, the forging press and the grinding of the ferrule raceway are processed by forming tools or anti-profile plates.
In addition, most of the bearings are standardized products. The bearings of the same type require a large amount. In order to improve productivity, reduce costs, ensure quality, and widely adopt new technologies and improve mechanization and automation, deep groove ball bearings are generally FAG. Bearing models and varieties are produced in large quantities, and even special automatic lines or assembly lines can be established for production
What is a miniature bearing
Miniature bearings are suitable for products requiring high speed, low friction torque, low vibration and low noise. They are a wide range of bearings.
Product Features
Among the ultra-small-aperture miniature bearings, the miniature bearings with an inner diameter of φ2mm or less have 18 types of metric 68, 69, 60 series, and 6 kinds of British R series. On this basis, they can also be divided into ZZ steel bearing dust cover series. , RS rubber bearing seal series, Teflon bearing seal series, flange series, stainless steel series, ceramic ball series, etc.
Miniature bearings are suitable for various industrial equipment, small rotary motors, etc. Recently, the demand for miniaturization, weight reduction, and thin walling of these devices has increased.
The main purpose
Office equipment ●Micro motor
Soft drive ● pressure rotor
Dental drill ● hard disk motor
Stepper motor ● recorder drum
Toy model ● computer fan
Encoder
Miniature bearing model comparison table:
Old model new model
241.2
2422
251.5 1000082682
252 MR52
252.32.3 682ZZ
252.52.5 2080082MR52ZZ
262.3 1000092692
2633 692ZZ
262.52.5 MR62ZZ
262.82.8 2080092
263.53.5 3080092A
272.52.5 80062MR72
2733 MR72ZZ
272.8 602
273.5 602ZZ
2.551.5 MR72X
2.552.32.3 MR72XZZ
2.561.8 100008/2.5682X
2.562.52.5 208008/2.5
2.562.62.6 682XZZ
2.572.52.5 108009/2.5692X
2.573.53.5 692XZZ
2.582.5 MR82X
2.5833 MR82XZZ
2.582.8 602X
2.5844 602XZZ
362 MR63
362.52.5 MR63ZZ
372 1000083683
372.52.5 2080083
3733 683ZZ
382.5 MR83
3833 MR83ZZ
383 1080093693
3844 2080093693ZZ
392.5 MR93
3944 MR93ZZ
393 13603
3955 80013603ZZ
3102.52.5 8080023
31044 80023623ZZ
31355 80033633ZZ
472 MR74
472.52.5 MR74ZZ
482 MR84
4833 MR84ZZ
492.5 1000084684
4933 2080084
493.53.5
4944 684ZZ
4103 MR104
41044 MR104ZZ
41144 1080094694ZZ
41155 2080094
41244 80014604ZZ
41355 80024624ZZ
41655 80034634ZZ
582 MR85
582.52.5 MR85ZZ
592.5 MR95
5933 MR95ZZ
5103 MR105
51044 MR105ZZ
5113 1000085685
5113.53.5 2080085
51144 3080085KMR115ZZ
51155 685ZZ
51344 1080095695ZZ
51355 2080095
51355 2080095
51366
51455 80015605ZZ
51655 80025625ZZ
51966 80035635ZZ
6102.5 MR106
61033 MR106ZZ
6123 MR126
61244 MR126ZZ
6133.5 1000086686
61344 2080086
61355 686ZZ
61366
61555 1080096696ZZ
61566 2080096
Product Features
Among the ultra-small-aperture miniature bearings, the miniature bearings with an inner diameter of φ2mm or less have 18 types of metric 68, 69, 60 series, and 6 kinds of British R series. On this basis, they can also be divided into ZZ steel bearing dust cover series. , RS rubber bearing seal series, Teflon bearing seal series, flange series, stainless steel series, ceramic ball series, etc.
Miniature bearings are suitable for various industrial equipment, small rotary motors, etc. Recently, the demand for miniaturization, weight reduction, and thin walling of these devices has increased.
The main purpose
Office equipment ●Micro motor
Soft drive ● pressure rotor
Dental drill ● hard disk motor
Stepper motor ● recorder drum
Toy model ● computer fan
Encoder
Miniature bearing model comparison table:
Old model new model
241.2
2422
251.5 1000082682
252 MR52
252.32.3 682ZZ
252.52.5 2080082MR52ZZ
262.3 1000092692
2633 692ZZ
262.52.5 MR62ZZ
262.82.8 2080092
263.53.5 3080092A
272.52.5 80062MR72
2733 MR72ZZ
272.8 602
273.5 602ZZ
2.551.5 MR72X
2.552.32.3 MR72XZZ
2.561.8 100008/2.5682X
2.562.52.5 208008/2.5
2.562.62.6 682XZZ
2.572.52.5 108009/2.5692X
2.573.53.5 692XZZ
2.582.5 MR82X
2.5833 MR82XZZ
2.582.8 602X
2.5844 602XZZ
362 MR63
362.52.5 MR63ZZ
372 1000083683
372.52.5 2080083
3733 683ZZ
382.5 MR83
3833 MR83ZZ
383 1080093693
3844 2080093693ZZ
392.5 MR93
3944 MR93ZZ
393 13603
3955 80013603ZZ
3102.52.5 8080023
31044 80023623ZZ
31355 80033633ZZ
472 MR74
472.52.5 MR74ZZ
482 MR84
4833 MR84ZZ
492.5 1000084684
4933 2080084
493.53.5
4944 684ZZ
4103 MR104
41044 MR104ZZ
41144 1080094694ZZ
41155 2080094
41244 80014604ZZ
41355 80024624ZZ
41655 80034634ZZ
582 MR85
582.52.5 MR85ZZ
592.5 MR95
5933 MR95ZZ
5103 MR105
51044 MR105ZZ
5113 1000085685
5113.53.5 2080085
51144 3080085KMR115ZZ
51155 685ZZ
51344 1080095695ZZ
51355 2080095
51355 2080095
51366
51455 80015605ZZ
51655 80025625ZZ
51966 80035635ZZ
6102.5 MR106
61033 MR106ZZ
6123 MR126
61244 MR126ZZ
6133.5 1000086686
61344 2080086
61355 686ZZ
61366
61555 1080096696ZZ
61566 2080096
2018年12月7日星期五
Rolling bearing knowledge
Section 1 Basic Structure of Rolling Bearings
The rolling bearing developed on the basis of plain bearings is based on rolling friction instead of sliding friction. Generally, the two ferrules, a set of rolling elements and a cage are highly versatile, standardized and serialized. High mechanical foundation parts. Due to the different working conditions of various machines, various requirements are imposed on the rolling bearing in terms of load capacity, structure and performance. For this reason, rolling bearings require a wide variety of structures. However, the most basic structure consists of the inner ring, the outer ring, the rolling elements and the cage.
The role of various parts in the bearing is:
For a radial bearing, the inner ring usually fits tightly with the shaft and operates with the shaft. The outer ring is usually in a transitional fit with the bearing housing or the mechanical housing bore for support. However, in some cases, there is also an outer ring running, the inner ring is fixed to support or the inner ring and the outer ring are simultaneously operated. For a thrust bearing, a shaft ring that fits tightly with the shaft and moves together, and a bearing ring that is in a transitional fit with the bearing housing or the mechanical housing bore and serves as a support. The rolling elements (steel balls, rollers or needles) are normally arranged in the bearing between the two ferrules by means of a cage for rolling motion. The shape, size and number of the bearings directly influence the load capacity and performance of the bearing. In addition to the uniform separation of the rolling elements, the cage can also function to guide the rotation of the rolling elements and improve the lubrication performance inside the bearing.
Section 2 Classification of rolling bearings
1. Classified by rolling bearing structure type
(1) Bearings are classified according to their load direction or nominal contact angle:
1) Radial bearings - mainly used for rolling bearings bearing radial loads, with nominal contact angles from 0 to 45. According to the nominal contact angle, it is divided into: radial contact bearing----the radial bearing with the nominal contact angle of 0: the radial angular contact bearing---the radial bearing with the nominal contact angle greater than 0 to 45.
2) Thrust bearings - mainly used for rolling bearings bearing axial loads, with nominal contact angles greater than 45 to 90. According to the different nominal contact angles, they are further divided into: Axial contact bearings----Thrust bearings with a nominal contact angle of 90: Thrust angular contact bearings---- Thrust bearings with a nominal contact angle greater than 45 but less than 90.
(2) Bearings are classified according to the type of rolling elements:
1) Ball bearing ---- rolling element is the ball:
2) Roller bearing----The rolling element is a roller. Roller bearings are divided into: roller bearings----rolling elements are cylindrical roller bearings. The ratio of length to diameter of cylindrical rollers is less than or equal to 3; needle roller bearings---- The rolling element is a needle roller bearing, the ratio of the length to the diameter of the needle roller is greater than 3, but the diameter is less than or equal to 5 mm; the tapered roller bearing----the rolling element is the bearing of the tapered roller; the spherical roller bearing one by one The rolling elements are bearings of spherical rollers.
(3) Bearings can be adjusted according to their work, divided into:
1) Self-aligning bearing----the raceway is a spherical shape, which can adapt to the angular deviation and angular movement between the two raceway axis lines;
2) Non-aligning bearings (rigid bearings)----bearings that can offset the axial angle between the raceways.
(4) Bearings are divided into: according to the number of rows of rolling elements:
1) Single row bearings----bearings with a row of rolling elements;
2) Double row bearings----bearings with two rows of rolling elements;
3) Multi-row bearings----bearings with more than two rows of rolling elements, such as three-row and four-row bearings.
(5) Bearings can be separated according to their components and are divided into:
1) separable bearings---bearings with separable parts;
2) Non-separable bearings----bearings that cannot be freely separated after the final assembly.
(6) The bearing can be divided into various structural types according to its structural shape (if there is no filling groove, whether there are inner and outer rings and the shape of the ferrule, the structure of the rib, or even the cage).
2. Classification according to the size of rolling bearings Bearings are divided into: according to their outer diameter size:
(1) Miniature bearings----bearings with a nominal outside diameter range of 26 mm or less;
(2) Small bearings----bearings with a nominal outer diameter range of 28-55mm;
(3) Small and medium-sized bearings----bearings with a nominal outer diameter range of 60-115mm;
(4) Medium and large bearings----bearings with nominal outer diameters ranging from 120-190mm
(5) Large bearings----bearings with a nominal outer diameter range of 200-430mm;
(6) Extra large bearings----bearings with a nominal outer diameter range of 440mm or more.
The basic production process of the third section rolling bearing
Due to the type of rolling bearing, structural type, tolerance class, technical requirements, materials and batches, the basic production process is not exactly the same.
First, the processing of the main parts of various bearings:
1. The processing of the ferrule: The processing of the inner and outer rings of the bearing varies according to the raw material or the form of the blank. The process before the machining can be divided into the following three types. The whole processing process is: bar or pipe material (Some bars need to be forged and annealed, normalized)----Car processing----heat treatment----grinding----finishing or polishing----final inspection of parts---- Anti-rust----into the warehouse----(to be combined with the package)
2. The processing of the steel ball, the processing of the steel ball also varies according to the state of the raw material, wherein the process before the frustration or the photosphere can be divided into the following three types, the process before the heat treatment, and can be further divided into the following Two kinds, the whole processing process is: bar material or wire cold punching (some bars need to be punched and annealed after cold pressing)----frustration, rough grinding, soft grinding or light ball----heat treatment- --- Hard grinding----fine grinding----finishing or grinding----final inspection group----rust prevention, packaging----into the warehouse.
3. The processing of the roller during the processing of the roller varies according to the raw materials. The process before the heat treatment can be divided into the following two types. The whole processing process is as follows: bar processing or wire cold rolling, string ring and soft grinding ----Heat treatment----string soft point----grinding outer diameter----grinding end face----finishing end face----fine grinding outer diameter----finishing outer diameter ---- Final inspection group----rust prevention, packaging----into the warehouse (to be combined with the package).
4. Processing of the cage The processing of the cage can be divided into the following two categories depending on the design structure and raw materials:
(1) Sheet → shear → punching → stamping forming → shaping and finishing → pickling or shot peening or stringing → final inspection → rust prevention, packaging → storage (to be combined)
(2) Processing of the solid cage: The processing of the solid cage varies according to the raw materials or the gross damage. The following four types of blanks can be divided into the following processing: The bar is Pipe, forgings, castings----car inner diameter, outer diameter, end face, chamfering----drilling (or pulling, boring)----pickling----final inspection---- Anti-rust, packaging----into the warehouse.
Second, the assembly process of rolling bearings:
Rolling bearing parts such as inner ring, outer ring, rolling element and cage, etc., after passing the inspection, enter the assembly workshop for assembly, the process is as follows:
Parts demagnetization, cleaning → internal and external rolling <ditch> road size grouping → combination set → check clearance → riveting cage → final inspection → demagnetization, cleaning → rust prevention, packaging → into the finished product warehouse (boxing, shipping 〉.
Section 4 Characteristics of Rolling 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.
The rolling bearing developed on the basis of plain bearings is based on rolling friction instead of sliding friction. Generally, the two ferrules, a set of rolling elements and a cage are highly versatile, standardized and serialized. High mechanical foundation parts. Due to the different working conditions of various machines, various requirements are imposed on the rolling bearing in terms of load capacity, structure and performance. For this reason, rolling bearings require a wide variety of structures. However, the most basic structure consists of the inner ring, the outer ring, the rolling elements and the cage.
The role of various parts in the bearing is:
For a radial bearing, the inner ring usually fits tightly with the shaft and operates with the shaft. The outer ring is usually in a transitional fit with the bearing housing or the mechanical housing bore for support. However, in some cases, there is also an outer ring running, the inner ring is fixed to support or the inner ring and the outer ring are simultaneously operated. For a thrust bearing, a shaft ring that fits tightly with the shaft and moves together, and a bearing ring that is in a transitional fit with the bearing housing or the mechanical housing bore and serves as a support. The rolling elements (steel balls, rollers or needles) are normally arranged in the bearing between the two ferrules by means of a cage for rolling motion. The shape, size and number of the bearings directly influence the load capacity and performance of the bearing. In addition to the uniform separation of the rolling elements, the cage can also function to guide the rotation of the rolling elements and improve the lubrication performance inside the bearing.
Section 2 Classification of rolling bearings
1. Classified by rolling bearing structure type
(1) Bearings are classified according to their load direction or nominal contact angle:
1) Radial bearings - mainly used for rolling bearings bearing radial loads, with nominal contact angles from 0 to 45. According to the nominal contact angle, it is divided into: radial contact bearing----the radial bearing with the nominal contact angle of 0: the radial angular contact bearing---the radial bearing with the nominal contact angle greater than 0 to 45.
2) Thrust bearings - mainly used for rolling bearings bearing axial loads, with nominal contact angles greater than 45 to 90. According to the different nominal contact angles, they are further divided into: Axial contact bearings----Thrust bearings with a nominal contact angle of 90: Thrust angular contact bearings---- Thrust bearings with a nominal contact angle greater than 45 but less than 90.
(2) Bearings are classified according to the type of rolling elements:
1) Ball bearing ---- rolling element is the ball:
2) Roller bearing----The rolling element is a roller. Roller bearings are divided into: roller bearings----rolling elements are cylindrical roller bearings. The ratio of length to diameter of cylindrical rollers is less than or equal to 3; needle roller bearings---- The rolling element is a needle roller bearing, the ratio of the length to the diameter of the needle roller is greater than 3, but the diameter is less than or equal to 5 mm; the tapered roller bearing----the rolling element is the bearing of the tapered roller; the spherical roller bearing one by one The rolling elements are bearings of spherical rollers.
(3) Bearings can be adjusted according to their work, divided into:
1) Self-aligning bearing----the raceway is a spherical shape, which can adapt to the angular deviation and angular movement between the two raceway axis lines;
2) Non-aligning bearings (rigid bearings)----bearings that can offset the axial angle between the raceways.
(4) Bearings are divided into: according to the number of rows of rolling elements:
1) Single row bearings----bearings with a row of rolling elements;
2) Double row bearings----bearings with two rows of rolling elements;
3) Multi-row bearings----bearings with more than two rows of rolling elements, such as three-row and four-row bearings.
(5) Bearings can be separated according to their components and are divided into:
1) separable bearings---bearings with separable parts;
2) Non-separable bearings----bearings that cannot be freely separated after the final assembly.
(6) The bearing can be divided into various structural types according to its structural shape (if there is no filling groove, whether there are inner and outer rings and the shape of the ferrule, the structure of the rib, or even the cage).
2. Classification according to the size of rolling bearings Bearings are divided into: according to their outer diameter size:
(1) Miniature bearings----bearings with a nominal outside diameter range of 26 mm or less;
(2) Small bearings----bearings with a nominal outer diameter range of 28-55mm;
(3) Small and medium-sized bearings----bearings with a nominal outer diameter range of 60-115mm;
(4) Medium and large bearings----bearings with nominal outer diameters ranging from 120-190mm
(5) Large bearings----bearings with a nominal outer diameter range of 200-430mm;
(6) Extra large bearings----bearings with a nominal outer diameter range of 440mm or more.
The basic production process of the third section rolling bearing
Due to the type of rolling bearing, structural type, tolerance class, technical requirements, materials and batches, the basic production process is not exactly the same.
First, the processing of the main parts of various bearings:
1. The processing of the ferrule: The processing of the inner and outer rings of the bearing varies according to the raw material or the form of the blank. The process before the machining can be divided into the following three types. The whole processing process is: bar or pipe material (Some bars need to be forged and annealed, normalized)----Car processing----heat treatment----grinding----finishing or polishing----final inspection of parts---- Anti-rust----into the warehouse----(to be combined with the package)
2. The processing of the steel ball, the processing of the steel ball also varies according to the state of the raw material, wherein the process before the frustration or the photosphere can be divided into the following three types, the process before the heat treatment, and can be further divided into the following Two kinds, the whole processing process is: bar material or wire cold punching (some bars need to be punched and annealed after cold pressing)----frustration, rough grinding, soft grinding or light ball----heat treatment- --- Hard grinding----fine grinding----finishing or grinding----final inspection group----rust prevention, packaging----into the warehouse.
3. The processing of the roller during the processing of the roller varies according to the raw materials. The process before the heat treatment can be divided into the following two types. The whole processing process is as follows: bar processing or wire cold rolling, string ring and soft grinding ----Heat treatment----string soft point----grinding outer diameter----grinding end face----finishing end face----fine grinding outer diameter----finishing outer diameter ---- Final inspection group----rust prevention, packaging----into the warehouse (to be combined with the package).
4. Processing of the cage The processing of the cage can be divided into the following two categories depending on the design structure and raw materials:
(1) Sheet → shear → punching → stamping forming → shaping and finishing → pickling or shot peening or stringing → final inspection → rust prevention, packaging → storage (to be combined)
(2) Processing of the solid cage: The processing of the solid cage varies according to the raw materials or the gross damage. The following four types of blanks can be divided into the following processing: The bar is Pipe, forgings, castings----car inner diameter, outer diameter, end face, chamfering----drilling (or pulling, boring)----pickling----final inspection---- Anti-rust, packaging----into the warehouse.
Second, the assembly process of rolling bearings:
Rolling bearing parts such as inner ring, outer ring, rolling element and cage, etc., after passing the inspection, enter the assembly workshop for assembly, the process is as follows:
Parts demagnetization, cleaning → internal and external rolling <ditch> road size grouping → combination set → check clearance → riveting cage → final inspection → demagnetization, cleaning → rust prevention, packaging → into the finished product warehouse (boxing, shipping 〉.
Section 4 Characteristics of Rolling 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.
2018年12月5日星期三
Basic knowledge of industrial rolling bearings
basic structure
The rolling bearing developed on the basis of plain bearings is based on rolling friction instead of sliding friction. Generally, the two ferrules, a set of rolling elements and a cage are highly versatile, standardized and serialized. High mechanical foundation parts. Due to the different working conditions of various machines, various requirements are imposed on the rolling bearing in terms of load capacity, structure and performance. For this reason, rolling bearings require a wide variety of structures. However, the most basic structure consists of the inner ring, the outer ring, the rolling elements and the cage.
The role of various parts in the bearing is:
For a radial bearing, the inner ring usually fits tightly with the shaft and operates with the shaft. The outer ring is usually in a transitional fit with the bearing housing or the mechanical housing bore for support. However, in some cases, there is also an outer ring running, the inner ring is fixed to support or the inner ring and the outer ring are simultaneously operated. For a thrust bearing, a shaft ring that fits tightly with the shaft and moves together, and a bearing ring that is in a transitional fit with the bearing housing or the mechanical housing bore and serves as a support. The rolling elements (steel balls, rollers or needles) are normally arranged in the bearing between the two ferrules by means of a cage for rolling motion. The shape, size and number of the bearings directly influence the load capacity and performance of the bearing. In addition to the uniform separation of the rolling elements, the cage can also function to guide the rotation of the rolling elements and improve the lubrication performance inside the bearing.
The rolling bearing developed on the basis of plain bearings is based on rolling friction instead of sliding friction. Generally, the two ferrules, a set of rolling elements and a cage are highly versatile, standardized and serialized. High mechanical foundation parts. Due to the different working conditions of various machines, various requirements are imposed on the rolling bearing in terms of load capacity, structure and performance. For this reason, rolling bearings require a wide variety of structures. However, the most basic structure consists of the inner ring, the outer ring, the rolling elements and the cage.
The role of various parts in the bearing is:
For a radial bearing, the inner ring usually fits tightly with the shaft and operates with the shaft. The outer ring is usually in a transitional fit with the bearing housing or the mechanical housing bore for support. However, in some cases, there is also an outer ring running, the inner ring is fixed to support or the inner ring and the outer ring are simultaneously operated. For a thrust bearing, a shaft ring that fits tightly with the shaft and moves together, and a bearing ring that is in a transitional fit with the bearing housing or the mechanical housing bore and serves as a support. The rolling elements (steel balls, rollers or needles) are normally arranged in the bearing between the two ferrules by means of a cage for rolling motion. The shape, size and number of the bearings directly influence the load capacity and performance of the bearing. In addition to the uniform separation of the rolling elements, the cage can also function to guide the rotation of the rolling elements and improve the lubrication performance inside the bearing.
Bearing friction coefficient
In order to facilitate comparison with plain bearings, the frictional moment of a rolling bearing can be calculated from the following formula according to the inner diameter of the bearing:
M=uPd/2
Here,
M: friction torque, mN.m
u: friction coefficient, Table 1
P: bearing load, N
d: nominal bearing inner diameter, mm
The friction coefficient u is greatly affected by the bearing type, bearing load, rotation speed, lubrication method, etc. The reference values of the friction coefficient when the rotation is stable under normal conditions are shown in Table 1.
For plain bearings, u = 0.01-0.02, and sometimes 0.1-0.2.
Friction coefficient of various types of bearings
Bearing type friction coefficient u
Deep groove ball bearings 0.0010-0.0015
Angular contact ball bearings 0.0012-0.0020
Self-aligning ball bearing 0.0008-0.0012
Cylindrical roller bearing 0.0008-0.0012
Full complement needle roller bearings 0.0025-0.0035
Needle roller bearing with cage 0.0020-0.0030
Tapered roller bearing 0.0017-0.0025
Spherical roller bearings 0.0020-0.0025
Thrust ball bearings 0.0010-0.0015
Thrust spherical roller bearings 0.0020-0.0025
M=uPd/2
Here,
M: friction torque, mN.m
u: friction coefficient, Table 1
P: bearing load, N
d: nominal bearing inner diameter, mm
The friction coefficient u is greatly affected by the bearing type, bearing load, rotation speed, lubrication method, etc. The reference values of the friction coefficient when the rotation is stable under normal conditions are shown in Table 1.
For plain bearings, u = 0.01-0.02, and sometimes 0.1-0.2.
Friction coefficient of various types of bearings
Bearing type friction coefficient u
Deep groove ball bearings 0.0010-0.0015
Angular contact ball bearings 0.0012-0.0020
Self-aligning ball bearing 0.0008-0.0012
Cylindrical roller bearing 0.0008-0.0012
Full complement needle roller bearings 0.0025-0.0035
Needle roller bearing with cage 0.0020-0.0030
Tapered roller bearing 0.0017-0.0025
Spherical roller bearings 0.0020-0.0025
Thrust ball bearings 0.0010-0.0015
Thrust spherical roller bearings 0.0020-0.0025
2018年12月4日星期二
Locomotive rolling bearing fault generation and diagnosis method
As the main components of the locomotive, especially the traction motor and the axle box bearing, its function plays an important role in the safe transportation. When the locomotive runs on the line, once the bearing fails, the whole train will not run, blocking the transportation line. Especially when the passenger train fails, the negative impact is even greater. At the same time, once the locomotive bearing fails, it is very difficult to repair the locomotive. Therefore, it is very important to prevent and reduce the occurrence of locomotive bearing faults. Whether the bearing with hidden troubles can be detected before the bearing is loaded, and the qualified bearing accessories are guaranteed to be the focus of this article {TodayHot}.
2 bearing failure
Serious damage to the bearing is often not caused by a single cause, but in a combination of several aspects, a vicious cycle occurs under severe operating conditions, resulting in severe bearing burnout, so after an accident, it is often difficult to judge What causes it, it also brings certain difficulties to us to develop relevant measures. For the convenience of discussion, we first analyze the causes of bearing failures from several aspects.
2.1 Abnormal wear of the bearing
2.1.1 When the bearing is used for a period of time, the inner ring of the bearing, the rolling element, the cage, the outer ring, the raceway, etc. produce certain defects and scars, resulting in poor lubrication of the bearing, causing heat generation of the bearing, long-term heating, Lead to: (1) dilution of bearing lubricants. (2) Accelerate the fatigue of the material and reduce the hardness. Due to the above reasons, a vicious cycle is further formed, and the overheating is accelerated to burn the bearing. Severe bearing inner ring displacement, rolling element out of round, collision heat, and finally welded together. Therefore, when running online, if {HotTag} finds that the bearing is seriously hot and smokes, do not stop, but keep running to the front station, because the overheated bearing is in a molten state at this moment, once it stops cooling, it can no longer walk, blocking the positive line. .
2.1.2 It is very important for the oil supply maintenance of locomotive bearings, especially for the proper amount of oil to ensure that the bearing has good lubrication. It is easy to cause bearing failure due to lack of oil and excessive oiling. Poor lubrication and heat. If it is added too much, it will easily cause agitation and overheating. Therefore, it is necessary to supply oil properly during maintenance. At the same time, the lubricating grease of the bearing is also very important. Once other impurities and moisture are dropped into the grease, it will affect the normal swimming. Gap and build the necessary oil film.
2.1.3 The bearing is used for too long, which exceeds the service life of the bearing and is prone to fatigue of the material. The strong impact of the material causes the material to deform, causing the roller and the raceway surface to peel off and crush, resulting in poor lubrication. And the vibration is increased.
2.2 Installation impact on bearings
2.2.1 Bearing inner ring and shaft fit clearance interference does not match, it is easy to cause bearing failure, large interference, it is easy to cause the bearing inner ring to crack due to excessive tensile stress, the interference is too small, also It is easy to cause the inner ring of the bearing to "relax".
2.2.2 Bearing assembly with improper clearance, it is easy to cause bearing failure, small clearance is easy to cause friction between the roller and the raceway. As the temperature rises, the bearing inner ring, rolling element, cage, outer ring The temperature of the end caps is not the same, there is a temperature difference between them, so the amount of expansion is also slightly different, which causes a further reduction of the matching clearance, and the heat generation of the bearing is added. If the gap is too large, the vibration of the roller is increased, which aggravates the impact of the roller and the raceway. At the same time, the internal load is unevenly distributed, the load roller is reduced, and the central roller load is excessive.
2.2.3 When the bearing is assembled, the bearing is not impacted by the copper hammer, which causes the cage to be deformed. The inner and outer rings of the traction motor bearing are not installed correctly or other reasons cause the axial traverse amount to disappear, causing the bearing shaft to collapse.
2 bearing failure
Serious damage to the bearing is often not caused by a single cause, but in a combination of several aspects, a vicious cycle occurs under severe operating conditions, resulting in severe bearing burnout, so after an accident, it is often difficult to judge What causes it, it also brings certain difficulties to us to develop relevant measures. For the convenience of discussion, we first analyze the causes of bearing failures from several aspects.
2.1 Abnormal wear of the bearing
2.1.1 When the bearing is used for a period of time, the inner ring of the bearing, the rolling element, the cage, the outer ring, the raceway, etc. produce certain defects and scars, resulting in poor lubrication of the bearing, causing heat generation of the bearing, long-term heating, Lead to: (1) dilution of bearing lubricants. (2) Accelerate the fatigue of the material and reduce the hardness. Due to the above reasons, a vicious cycle is further formed, and the overheating is accelerated to burn the bearing. Severe bearing inner ring displacement, rolling element out of round, collision heat, and finally welded together. Therefore, when running online, if {HotTag} finds that the bearing is seriously hot and smokes, do not stop, but keep running to the front station, because the overheated bearing is in a molten state at this moment, once it stops cooling, it can no longer walk, blocking the positive line. .
2.1.2 It is very important for the oil supply maintenance of locomotive bearings, especially for the proper amount of oil to ensure that the bearing has good lubrication. It is easy to cause bearing failure due to lack of oil and excessive oiling. Poor lubrication and heat. If it is added too much, it will easily cause agitation and overheating. Therefore, it is necessary to supply oil properly during maintenance. At the same time, the lubricating grease of the bearing is also very important. Once other impurities and moisture are dropped into the grease, it will affect the normal swimming. Gap and build the necessary oil film.
2.1.3 The bearing is used for too long, which exceeds the service life of the bearing and is prone to fatigue of the material. The strong impact of the material causes the material to deform, causing the roller and the raceway surface to peel off and crush, resulting in poor lubrication. And the vibration is increased.
2.2 Installation impact on bearings
2.2.1 Bearing inner ring and shaft fit clearance interference does not match, it is easy to cause bearing failure, large interference, it is easy to cause the bearing inner ring to crack due to excessive tensile stress, the interference is too small, also It is easy to cause the inner ring of the bearing to "relax".
2.2.2 Bearing assembly with improper clearance, it is easy to cause bearing failure, small clearance is easy to cause friction between the roller and the raceway. As the temperature rises, the bearing inner ring, rolling element, cage, outer ring The temperature of the end caps is not the same, there is a temperature difference between them, so the amount of expansion is also slightly different, which causes a further reduction of the matching clearance, and the heat generation of the bearing is added. If the gap is too large, the vibration of the roller is increased, which aggravates the impact of the roller and the raceway. At the same time, the internal load is unevenly distributed, the load roller is reduced, and the central roller load is excessive.
2.2.3 When the bearing is assembled, the bearing is not impacted by the copper hammer, which causes the cage to be deformed. The inner and outer rings of the traction motor bearing are not installed correctly or other reasons cause the axial traverse amount to disappear, causing the bearing shaft to collapse.
2018年12月3日星期一
Classification of joint bearings
Radial spherical plain bearings, angular contact spherical plain bearings, thrust joint bearings, thrust joint bearings, rod end joint bearings, self-lubricating radial joint bearings, self-lubricating angular contact joint bearings, self-lubricating thrust joint bearings, self-lubricating rod end joint bearings
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