Aligning ball bearings during operation shock factor analysis

Bearing is the main source of vibration shaker difficult to control, because the shaker is a great incentive by the work force to maintain the speed limit and the friction coefficient  spherical plain bearings, so bearing radial force suffered great shaker at work process, a lot of exciting force will cause the elastic vibration bearing system. If poor lubrication, it will have a greater friction bearing temperature is too high, the thermal expansion is too large, the radial clearance is significantly reduced, which in turn exacerbated the friction, temperature further.
Plain bearing locking way into two types:
1. staring screws attached bearing inner ring tight simply extend the partial locking screw nails, you can put export bearing fixed peg locking screw with hex wrench. Please select the appropriate size Allen wrench.
2. The locking sleeve bearings attached fair fair locking sleeve has a recess aligning ball bearing vibration and temperature within the recesses Kong its level in the bearing inner ring is also a local fair. First fair on the inner sleeve is positioned toward the direction of the axis of rotation, the rapid rotation of the bearing sleeve know chucking fair date, hex wrench to lock the screw tightly.
Vibration system with eccentric triple row roller slewing bearing system components, can be regarded as a single degree of freedom system. bearing drive shaft and the driven shaft systems exist in the resonant frequency of a certain value, and if a resonance frequency of the excitation frequency close to the resonance. In addition, due to the eccentricity of the existence of centrifugal force, it will produce bending vibrations affect bearing life of material factors, if the speed close to the critical value, the occurrence of bending resonance.
From falling off, indentation, corrosion, cracks, wear, etc. will be in bearing vibration measurement reflected, the bearing vibration of the bearing damage is very sensitive, so aligning ball tower crane bearing through the use of special bearing vibration measurements (frequency analyzer, etc.) to measure the size of vibration frequency can not be inferred by abnormal circumstances. After Since the measured values ​​due to the conditions of use or the sensor mounting position of the bearing, etc., and therefore requires prior to measurements of each machine are analyzed and compared to determine the criteria.
Because bearing even a slight peeling damage, abnormal tone and irregular tone will be issued, and therefore can be used to distinguish sound measuring device, the use of sound measuring device for the sound operation of the rolling bearing size and quality to be checked, since to advance the role of prevention.
If the use of the hole can be measured directly bearing outer ring temperature, is more appropriate position. In general, the temperature of the bearing, the bearing chamber is generally based on the outside temperature can be inferred. If lubrication, install the appropriate department, the self-aligning ball bearing temperature will be rapid rise, there will be abnormal high temperature, when to stop running and take the necessary precautions. Typically,  bearing temperature rise slowly with the start of the operation, after 1-2 hours to reach steady state. The normal temperature of the bearing due to heat capacity, heat capacity, speed and load of the machine and different. If necessary, you can always use heat sensors to monitor bearing operating temperature, and automatic alarm user or stop to prevent burning shaft accident temperature exceeds a predetermined value.

Thrust ball bearings running track installation methods judgment

When truck mounted crane bearing rotates when the raceway thrust ball bearing inner and outer rings and rolling elements due to rolling contact, so run track for the dark side, running track attached to the roller surface are not unusual, thus becomes load conditions can be learned, so when dismounting bearings, please pay attention and observe strict raceway running track.
Thrust ball bearings are correctly installed, affecting accuracy, longevity, performance. Therefore, the design and assembly department to adequately studied bearing installation. I hope to be in accordance with the operating standards for installation. Operating standards of the project generally as follows:
(1), cleaning bearings and related components
(2), size and finishing Check the connected components
(3), the installation
(4) After installation check the bearings
(5), supplying lubricant
Immediately prior to installation, open wind power bearing package. General grease lubrication, no cleaning, directly filled grease. Lubricating oil, do not clean the ordinary, however, the instrument used or high-speed bearings, etc.
Oil use clean wash, remove coating on the bearing rust inhibitor. Removing the bearing rust inhibitor, rust, it can not be placed in the air. For have a grease-enclosed bearing, can be used directly without washing.
four point contact ball slewing bearing installation method, because the bearing structure, with the condition varies, in general, due to multi-axis rotation, so the inner need interference fit. Cylindrical bore bearings, the use of press push, or by hot charging methods. Cone of the occasion, mounted directly on the tapered shaft or sleeve installation.
When mounted to the housing, usually with more clearance, the outer ring interference, usually pressed into the press or shrink fit method also cooling installation. With dry ice as coolant, shrink fit installation situations, moisture in the air will condense on the surface of the bearing. Therefore, proper corrosion protection.
If you look at the trajectory, then this will only burden that radial load to bear large axial load, to withstand the torque load on the bearing housing or extreme rigidity inequality. You can check whether the bearing loads and unexpected plus installation errors, such as whether the ANC and became prosecuted bearing loss for clues to the cause.

Way of bearing temperature during processing by lubricating spherical roller

There are pre-filled with grease greased sealed manner in sealed bearings, as well as inside the casing filled with the right amount of grease at regular intervals to supplement or replacement for grease filling mode. In addition, there are many excavator bearing  eed lubricating machinery, also uses the pipe connected to the lubrication at centralized way for fat. Grease filling can be done after the first time without grease supplement, and its structural sealing device is also relatively simple, so widely used. Lubricating oil is relatively simple. Regular lubrication can greatly improve the spherical roller bearing life Oh!
bearings when the temperature rises, first determine whether the error first move to do, if the temperature is indeed rising, Dangdang that do the following disposition:
(1) Check the cooling water pressure, flow and piping system can generally bearings. If water filter may be clogged down, can not timely disposal of hot disassembly spherical plain bearings ylindrical bore bearings can shut down the disposal, can work when the confirmation is done, then put into use.
(2) When the check governor oil pressure, oil pressure may result if the cooling water hydraulic valve closed.
(3) check whether no bearing spherical ball with the outside of the soundtrack, and can not detect bearing swing very much.
(4) to take oil samples to see whether the oil did not change color, bearing and conduct tests to see whether the variables. If confirmed deterioration, stop change when the new oil.
(5) Check the oil standard oil level can generally, if the non-general, check whether the tank drain valve closed. If the bearing is not closed, when up the oil, if oil leakage sealing pads, when stopping for disposal.
Bearing lubrication performance can be divided into the following areas:
1, the first portions of lubricating spherical roller bearings, reducing bearing friction and wear;
2, the rolling contact surfaces of the bearing oil film often form appropriate to extend the fatigue life of the bearing;
3, through the heat inside the bearing lubrication away due to friction or other causes;
4, by ship loader bearing lubrication to the role of rust and dust.

Tapered roller bearings for use in the environment under which

tapered roller Full complement cylindrical roller bearing are precision components, its use should also be carefully carried out. No matter how high-performance bearings, if used improperly, it will not get the expected performance. Use Notes on tapered roller bearings are as follows.
First, keep tapered roller bearings and their surroundings clean
Even tiny invisible dust into the tapered roller bearings, will increase wear, vibration and noise of the bearing. tapered roller bearings and its peripheral accessories should be kept clean, especially the dust and dirt, tools and working environment must be kept clean.
Second, when using the installation to be carefully
Does not allow a strong punch, not allowed to use a hammer, a direct hit  tapered roller bearings are not allowed to pass through the rolling pressure.
Third, the use of appropriate and accurate installation tool
Try using a dedicated tool, try to avoid using fabric and staple fiber stuff like that.
Fourth,  tapered roller bearings to prevent corrosion
Direct hand pick  tapered roller miniature linear bearings  to fully wash hands sweat, and coated with high quality mineral oil and then operate in the rainy season and summer with particular attention to rust. However, in some special operating conditions, the bearing can be obtained in a longer life of traditional computing, especially under light load conditions. These particular operating conditions that, when the rolling surface (track and rolling elements) are effectively separated and limit pollutants may cause surface damage of a lubricant film. In fact, under ideal conditions, the so-called permanent tapered roller bearing life is possible.
Use the site and conditions of use and environmental conditions to select size, precision, with appropriate tapered roller bearings based on the bearing life and viability of the premise.
1, using the site: tapered roller bearings for joint load to bear radial load mainly radial and axial, usually paired with two sets of crossed roller bearings  primarily for automotive front and rear hub, active gear, differential , a reducer and other transmission parts.
2, the permissible speed: install properly oiled environment, allowing for tapered roller bearings 0.3-0.5 times the speed limit. Under normal circumstances, to 0.2 times the speed limit is the most appropriate.
3, allowing the tilt angle: Tapered roller bearings are generally not allowed to tilt axis relative to shell hole, if inclined, to a maximum of 2 '.
4, allowing the temperature: in under normal load, and lubricant high temperature performance, and under conditions sufficient lubrication, tapered roller bearings are generally allowed to work at -30 ℃ -150 ℃ ambient temperature.

One way bearing technology principle

A ramp and roller design

Ramp and roller one-way clutch inner diameter of the outer drum consists essentially, with the slope and the inner spring force to bear and were always in close contact with the inner and outer rings consisting of a set of rollers. As long as one of the rotating raceway on its impact on the direction of movement has become another industry, this arrangement ensures immediate and guaranteed the ability to go beyond the speed of the drive immediately from nature.

Use:

The design of the one-way truck mounted crane bearing can fit beyond, indexing and non-return of use in a variety of environments.

When used as a use beyond the one-way clutch

Slope-style, one-way roller clutch will be installed in this manner, is to go beyond the outer ring as a member. This point is very important for high-speed beyond. Beyond the use of the inner ring, acting on the roller speed is limited by the centrifugal force will cause beyond.

When used as an anti-kickback when using one-way clutch

Only rotating the inner roller ramp type one-way clutch is adapted to a relatively low speed. If the required speed is higher than the recommended speed, we recommend using the wedge-way clutch.

When used as an indexing using a one-way clutch

The outer ring is often seen as the swing elements are often seen from the inner components. Otherwise, rollers and spring inertia will cause errors, especially at high frequencies indexing. Diluted lubricant use and powerful springs provides high-speed indexing accuracy and quality of.

2, the wedge design

This wedge roughly one-way clutch retainer consists of a strong spring and bearing inner and outer rings, wedges group, wedge. Including wedge to wedge between the outer ring to roll from one track to another raceway transfer power. Wedge has both a diagonal diameter (that is, from one corner to the other on the wedge angle distance) is greater than the other one. In a relatively large cross-section to force the wedging action occurs when the relative rotation of the outer ring inner wedge greater vertical position.

3, self-locking angle

Rely mainly on the wedge wedging action between the inner and outer rings and self-locking wedge angle. The basic concept of the one-way clutch wedge wedge friction coefficient requirements drive the direction of the inner ring with sudden torque of a relationship, the friction value must be greater than the tangent of the angle of self-locking. If the conditions are unsafe, wedging will not happen.

Self-locking by the wedge angle is determined by the structure, the point on the inner and outer rings were used to wedge and its connections.

The initial design of the wedge has a very low self-locking angle to ensure the absolute binding at the beginning. With the increase, the wedge will generate a torque so that the wedge but raceway radial deflection forces, resulting in a wedge roller to a new location. Wedges are often designed with a self-locking can be gradually increased angle, and it is up to the same position from beyond the position of the maximum load marine crane bearing. Relatively large self-locking wedge angle can be reduced by producing a radial force, so long as the ultimate elongation and Brinell hardness requirement allows greater torque is transmitted.

Bearing materials heat treatment of new technology

Currently aeroengine bearings standard materials at temperatures up to 300 ℃ condition with good fatigue strength of high-speed steel. However, when the bearing is running at a high speed or very high speed, the material properties of fracture toughness of this material, the hardness and the resistance to crack generation and scalability can not meet the requirements.
In order to improve the material structure, improve material properties, development of aircraft engine technology to meet the requirements of the bearing, ship loader bearing three different existing materials were studied by experiments illustrate the relationship between microstructure and properties of materials. These three materials are A casting hot rolled steel (M2), one kind of powder metallurgy material (ASP23) and a carbonaceous 0.65 (weight percent), low content of alloying elements of high speed steel derived material.
1. Fracture Toughness
In aircraft engines, since the high speed of the bearing, and the resulting strong centrifugal force, and therefore the fracture toughness of the bearing material is particularly important.
In the hardened high speed steel, carbide fracture process including initial gap caused by the emergence of crack or cracks at the end of the elastic region due to the martensitic matrix microstructure caused decohesion produce. Studies have shown that these three materials, the material with the improvement of toughness, hardness decreased, and the quenching temperature decreases.
This is mainly due to the lower half of the martensitic matrix content and improve tissue elasticity actions. Most carbide steel hardened by a low temperature, they choose adversely affect fracture toughness. In the case of low hardness, since the material yield strength decreased, the difference between the low hardness of the steel depends on Fracture explants taken to the distribution of carbides at high hardness, the decrease in the volume occupied by carbides, carbide and the size of the gap between the elastic material is about the same.
In this case, the fracture toughness is no longer primarily depends on the distribution of carbides and matrix tissue elasticity is also the smallest. Therefore, the fracture toughness values ​​of the three material concentrated in 750HV and higher hardness. Under low hardness, a large area of the elastic case, by increasing the diameter of the carbide or carbides in the reduced hardness of the same conditions the ratio of the fracture toughness can be improved. Further, when the hardness, fracture toughness value of the rate of change is lowered. When the elastic region carbide gap between small and large, the matrix effect
on the fracture toughness of the largest organizations.In short, the fracture toughness of high speed steel mainly depends on the elastic matrix structure, and matrix organizational flexibility also affected by the carbon content of martensite and its largely. The researchers also pointed out that of course can not be ruled out starting carbide, residual stress, and other factors affecting the residual austenite and martensite tempered from precipitation of carbides, such as fracture toughness.
2. The development of fatigue cracks
Researchers crack development process into the following phases:
The first stage, cracks began to expand. Although the critical stress intensity high-speed steel can be changed by heat treatment, but the range is not large absolute value, between 3 ~ 5MPa / m2.
The second stage, crack propagation. Crack growth rate was also similar to the high-speed steel, as in the case 10Mpa / m2, the approximately 5 × 10-6mm / cycle. But with a large steel toughness can slow down the speed of crack propagation.
The third stage, the rapid expansion of the crack. When the crack reaches this stage, mobile crane bearing soon fail.
3. Surface Treatment
According to the study of the relationship between the fracture toughness and other materials crack development process and analysis, we can see that in the presence of high and dn value hoop stress of the situation, the low carbon content of the surface treatment and high-speed steel HSS hardened surface depth change is significant. For this reason, development of a surface treatment process, can enhance the surface hardness and compressive stresses. Surface-treated material has the following characteristics: has good resistance to fatigue crack resistance, the second stage, fracture toughness values ​​have
lower crack growth rate and insufficient hardening or due to the low carbon content of the core material of higher and so on.Such surface treatment method developed comprising:
(1) with a laser, electron beam or induction hardening methods such as inadequate hardened local heat treatment, in order to obtain a surface hardened layer. It should be noted that hardening is insufficient to increase the fracture toughness.
(2) obtained by chemical treatment hardened surface layer. Such methods include carbon or nitrogen to penetrate into the ordinary high-speed steel microstructure, or a small change in the carbon content of the degree.
In short, the company believes in the development of new or improved analysis method of steel heat treatment process for the next generation of aircraft engines, considerable benefit can be obtained from the resulting effect of surface treatment. It can be said that if this microstructure and heat treatment related to the development of the means of mechanical properties once people fully grasp, hardenability steel and high speed steel is bound to be fully utilized in the aero-engine bearings.

The factors of slim ball bearing

A large number of domestic and international tests show: cage, collar, processing quality ball bearing vibration having different degrees of impact, which processing quality ball bearing vibration impact on the most obvious, followed by rings of processing quality, the most important influence factor is the roundness of the ball and rings, waviness, roughness, surface bump injuries.
Our ball products most prominent problem is the discrete vibration, surface defects serious (single point, the group points, pits, etc.), although the surface roughness, size, shape, and the error is not lower than the level of the loop, but the co-sets After high slim ball bearing vibration, and even different sound, the main problem is the waviness no control (no standard, no proper testing of the instruments), while the description of the machine vibration resistance poor, wheel, grinding disc, coolant, process parameters are problematic ; on the other hand to improve the management level, to avoid the bump injuries, scratches, burns and other machines of quality problems at any time.
For rings, the most serious impact of bearing vibration is channel waviness and surface roughness. For example, small and medium deep groove ball bearings inside and outside the channel roundness greater than 2μm, will have a significant impact on the bearing vibration, while the inner and outer channel waviness greater than 0.7μm, slewing ring bearing vibration value increases with increased waviness, the channel serious gouges Vibration can rise more than 4dB, and even different tone.
Whether balls or rings, waviness produced in grinding, superfinishing although you can improve waviness and roughness reduced, but the most fundamental measure is to reduce the process of ultra-fine grinding waviness, avoid randomness bump hurt, there are two main measures:
First, reduce the vibration of the rolling surface of ultra-fine grinding time, get a good shape accuracy and surface finish quality surface texture to reduce vibration, wear super machine must have good vibration resistance, bed and other important structural member having vibration absorption, super precision machine tools Whetstone oscillation system with good anti-vibration performance; improve grinding speed, grinding 6202 foreign commonly used outer raceway 60,000 spindle, grinding speed 60m / s or more, domestic general much lower, mainly due to the spindle and restrictions main bearing performance.
When the high-speed grinding, grinding force is small, thin grinding deterioration, do not burn easily, but also can improve the precision and efficiency, a significant impact on low-noise ball bearings; spindle speed characteristics of static and dynamic stiffness and low noise ball bearing large grinding vibration, the higher the stiffness, grinding speed, the less sensitive to changes in the grinding force, grinding system vibration is smaller; increase support rigidity spindle bearings, using random balancing technology to improve
the grinding spindle vibration sex. Foreign grinding vibration velocity approximately one tenth the domestic general spindle; Whetstone wheel is essential to improve the quality of cutting and trimming. China is currently the main problem is wheel Whetstone uniformity poor organizational structure, seriously affecting the ultra low noise ball bearing grinding process quality; sufficiently cooled, improve filtering accuracy; improve the resolution of the fine feed to the system, reduce the feed inertia; super reasonable processing mill process parameters and manufacturing processes are factors that can not be ignored, grinding allowance should be small, geometric tolerances and strict,
small ball ferris wheel bearing diameter should not use super-lapping, super coarse grinding should be separated to ensure good surface quality.
The second is to improve the machining accuracy of the reference plane, reduce grinding and superfinishing process of error reflection end surface is the outer diameter of the grinding process of super-positioning reference. The outside diameter of the channel ultra fine error reflection on the ditch by the outside diameter grinding, grinding on ditch super error reflection passed indirectly. If the work piece bump hurt in the transfer process, the complex will be directly mapped onto the raceway machined surface, the impact of bearing vibration. So you must take the following measures: to improve the positioning reference surface shape accuracy; processing pass smooth, no bump injury; rough allowance geometric error can not be too large, especially when allowance is small, too large error
will result in a final grinding and ultra-fine At the end of the final shape accuracy has not been improved to the quality requirements, seriously affect the consistency of the processing quality.
From the above analysis is not difficult to see: Auto-line consists of high performance, high stability of the machine system consisting of grinding the most suitable machining ultra low noise ball bearing, avoid bump hurt, reduce transmission error, eliminate artificial factors, improve processing efficiency and quality consistency reduce production costs and improve efficiency.