Causes and solutions of the hottest bearing damage

2022-08-09
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Reasons and solutions for bearing damage

bearings are precision parts, so they require considerable caution in use, that is, high-performance bearings are used. If they are not used properly, they cannot achieve the expected performance effect, and they are easy to be damaged. Therefore, the following matters should be paid attention to when using the bearing:

first, keep the bearing and its surrounding environment clean

even if the invisible smile dust enters the bearing, it will increase the wear, vibration and noise of the bearing

II. Be careful when using and installing

it is not allowed to punch forcefully, to knock the bearing directly with a hammer, or to transmit pressure through the rolling element

III. use appropriate and accurate installation tools

try to use special tools and try to avoid using things such as cloth and short fiber

IV. prevent the corrosion of bearings

when taking the bearings directly by hand, it is necessary to fully wash the sweat from your hands and apply high-quality mineral oil before operation, especially pay attention to rust prevention in rainy seasons and summer

however, under certain special operating conditions, the bearing can obtain a longer life than the traditional calculation, especially under light load. These special operating conditions are the surface damage that may be caused when the rolling surface (track and rolling parts) is effectively separated and limited by a lubricating oil film. In fact, under ideal conditions, the so-called permanent bearing life is possible

why is the bearing worn out

only some bearings are damaged in practical application

most of the reasons for bearing failure are beyond the original estimated load, ineffective sealing, too small bearing clearance caused by too tight fitting, etc. Any of these factors has its special damage type and will leave special damage traces. Therefore, by examining the damaged bearing, we can find the possible causes in most cases. Generally speaking, one third of the bearing damage is caused by fatigue damage, the other one is caused by poor lubrication, and the other one is caused by pollutants entering the bearing or improper installation and treatment

however, these damage patterns are also related to industry. For example, in the pulp and paper industry, bearing damage is mostly caused by poor lubrication or pollution rather than material fatigue

countermeasures:

causes of damage measures

excessive peel load. Poor installation (non-linear)

moment load foreign matter intrusion and water ingress

poor lubrication, inappropriate lubricant

improper bearing clearance. Poor accuracy of bearing housing, uneven rigidity of bearing housing

development caused by large deflection of shaft, rust, erosion points, scratches and indentations

(surface deformation phenomenon). Check the size of the load and study the bearings used again

improve the installation method

improve the sealing device and rust prevention during shutdown

use lubricants with appropriate viscosity and improve lubrication methods

check the accuracy of the shaft and bearing housing

check the clearance

when the bearing rotates under load, the raceway surface or rolling surface of the inner ring and outer ring presents fish scale peeling phenomenon due to rolling fatigue

peeling lubricant is inappropriate

foreign matters enter the lubricant

poor lubricant causes rough surface

the surface finish of paired rolling parts is poor. Choose lubricant

improve the sealing device

improve the surface finish of mating rolling parts

shows a dark surface with slight wear, on which there are many micro cracks as deep as m from the surface to the inside, and small peeling (micro peeling) occurs in a large range.

it is broken and hit during installation

the load is too large

poor use such as falling. Improve the installation method (adopt hot installation and use appropriate tool clips)

correct load conditions

the bearing is installed in place so that the retaining edge is supported

the so-called fracture refers to a small part of the fracture due to the impact or excessive load on the local part of the flange or roller angle of the raceway wheel

get stuck with excessive load and preload

poor lubrication

foreign body bite

inclination of inner ring and outer ring and deflection of shaft

the accuracy of shaft and bearing housing is poor. Check the size of the load

preloading should be appropriate

improve lubricants and lubrication methods

check the accuracy of shaft and bearing housing

the so-called stuck injury is the surface damage caused by the collection of minor burns in the part of the sliding surface injury

linear scars on the slide surface and rolling surface in the circumferential direction

cycloid scar on the roller end face

jamming on the shaft ring near the roller end face

scratch high speed light load

rapid acceleration and deceleration

inappropriate lubricant

water intrusion improvement preloading

improvement of bearing clearance

use of lubricant with good oil film

improvement of lubrication method

improvement of sealing device

the so-called scratch is the quotient of re raceway surface and rolling surface, and there is surface damage that occurs with the aggregation of minor burns caused by rolling slip and oil film hot cracking. Produce surface roughness with adhesion

cracks and excessive interference of cracks

excessive load, impact load

stripping has developed

heat and micro vibration wear caused by the contact between the raceway wheel and the mounting components

heating caused by creep

the taper angle of the taper shaft is poor

the cylindricity of the shaft is poor

the fillet radius of the shaft step is larger than the bearing chamfer, resulting in interference with the bearing chamfer. The interference is appropriate

check the load conditions

improve the installation method

the shape of the shaft should be appropriate

the so-called crack refers to the crack damage of the raceway wheel or rolling element. If it continues to be used, it will also include cracks with crack development

damage of cage and poor installation (non linearity of bearing)

poor use

large moment load

impact, large vibration

the speed is too high, and the acceleration and deceleration are rapid

poor lubrication

temperature rise. Check the installation method

check the load, rotation and temperature conditions

reduce vibration

correct the selection of cage

change the lubricant and lubrication method

the damage of cage includes the change of cage copper and copper products, which are the characteristics of Tongling City, such as industrial form, breakage, wear and tear, etc

column damage

deformation of the end face

wear of concave surface

the guide surface is worn

bite of foreign matters such as indentation metal powder

excessive impact load during assembly or transportation. Impact the shaft sleeve

improve the sealing device

filter the lubricating oil

improve the assembly and use methods

dents on the raceway surface or rotating surface when biting small metal powders, foreign objects, etc

due to the impact during installation, a concave surface (Brinell hardness indentation) is formed on the spacing of the rolling elements

abnormal wear Figure 2: the development caused by the invasion of haydale and some final user cooperation, rust and electric erosion

poor lubrication

slip caused by irregular movement of rolling elements. Improve the sealing device

clean the bearing housing

fully filter the lubricating oil

check the lubricant and lubrication method

prevent non-linearity

the so-called wear erosion causes wear on the raceway surface or rolling surface, roller end face, shaft ring surface and concave surface of cage due to friction

foreign matters bite in the lubrication process of pear peel like points

condensation due to moisture in the air

poor lubrication. Improve the sealing device

fully filter the lubricating oil

use a suitable lubricant

weak gloss dark pear skin pitting on the raceway surface

micro vibration wear and poor lubrication

small amplitude swing motion

insufficient interference. Use appropriate lubricant

preload

check the interference

apply lubricant to the mating surface

the wear caused by the relatively repeated small East China between the two contact surfaces occurs on the contact part between the raceway surface and the rolling element

due to the occurrence of reddish brown and black wear powder, the page is called micro vibration wear corrosion

the vibration and swing of the bearing at standstill during transportation due to pseudo Brinell indentation

swing motion with small amplitude

poor lubrication. Fix the shaft and bearing housing during transportation

the inner ring and outer ring shall be packed separately during transportation

add preloading to reduce vibration

use appropriate lubricant

during micro vibration, the wear of the contact part between the rolling element and the raceway wheel develops due to vibration and shaking, resulting in impressions that are cumulative like Brinell impressions

ground potential difference between outer ring and inner ring of electric erosion. When setting the circuit, the current should not flow through the bearing part

insulate the bearing

the so-called electric erosion refers to the phenomenon that when the current flows in the contact part between the bearing raceway wheel and the rolling body, sparks are sent out through the thin lubricating oil film, and local melting and concave convex appear on its surface

insufficient creep interference or clearance fit

the tightening sleeve is not tightened enough. Check the interference and take measures to stop rotation

tighten the set sleeve properly

study the accuracy of the shaft and the bearing housing of all parts cleaned in a clean, compatible commercial solvent

axial preloading

the side of the raceway wheel is fastened

bonding mating surface

apply lubrication PWA to the mating surface - compressive strength of wrapped carton (n); Agents

the so-called creep refers to the relative sliding between the mating surfaces when there is a gap on the mating surface of the bearing. In terms of the mating surface with creep, the mirror surface appears bright or dark, and sometimes the page is damaged and worn

discoloration and poor lubrication

reaction with lubricant causes hot oil immersion

the temperature rises greatly. Improve lubrication methods

due to temperature rise, lubricant reaction, etc., color change of raceway wheel, rolling element and cage

burn and poor lubrication

excessive load (excessive preload)

the speed is too high

the clearance is too small

invasion of water and foreign matters

the accuracy of shaft and bearing housing is poor, and the deflection of shaft is large. Study lubricants and lubrication methods

correct the selection of bearings

study the fit, bearing clearance and preload

improve the sealing device

check the accuracy of the shaft and bearing housing

improve the installation method

the raceway wheel, rolling element and cage are heated sharply during rotation until discoloration, softening, deposition and damage

invasion of rust, corrosive water and corrosive substances (paint, gas, etc.)

inappropriate lubricant

water droplets are attached due to the condensation of water vapor

stop when it is hot and wet

poor rust prevention during transportation

improper storage status

improper use. Improve the sealing device

study lubrication methods

rust prevention measures during shutdown

improve storage methods

pay attention when using

the rust and corrosion of bearings include pit like rust, full-scale rust and corrosion on the surface of raceway wheels and rolling elements

installation scar impact load of inner ring and outer ring during installation and disassembly. The impact load is prevented by using the appropriate tool

using the press

mutual centering during installation

wait during installation and disassembly

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