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| Bearing usage and maintenance
| bearing usage points for attention
Compared with common machinery components, roller bearing has higher sophistication degree, therefore greater care should be taken for its usage.
1) keep clean the bearing and its neighboring area
2) use the bearing with care
Bearings will show hitting scar, pressing scar, and breaking scars if they are used carelessly and struck forcefully
3) use appropriate tools
4) attend to the anti-rust of bearing
Avoid use in humid places and gloves should be worn in order not to wet the bearing with sweat.
5) users should be familiar with the bearing
6) set up procedure regulations for bearing usage
a 、 bearing maintenance
b 、 keep clean the bearing and its neighboring area
c 、 check for the size of the installation position and for the processing quality
d 、 installing practice
e 、 check after installation
f 、 disassembly practice
g 、 maintenance practice (periodically checked)
h 、 lubricant supplement
Bearings before leaving the factory all have due anti-rust oil and are packed in anti-rust paper. As long as the package is not damaged, the bearings' quality will be ensured. In the case of long-time storage, bearings should be put in the shelves that are 30 cm above the ground, with the humidity below 65% and the temperature being 20 ≧ . In addition , the storage place should avoid direct sunshine and contact with cold wall.
points for attention before installation
1) preparation for bearings
Do not unpack the bearings till the time for immediate installation since the bearings have anti-rust treatment and package.
In addition, the anti-rust oil spread on the bearings has good lubricating quality, so that the bearings can be used straightly without rinse for the bearing usage of common purposes and as lubricant supplement.In the case of bearing used on meters and in high-speed rotation, the anti-rust oil should be rinsed by clean rinsing oil and at this time the bearings easily get rusty, hence inappropriate for long-time storage.
2) examination of bearings and their outer shell
Rinse bearings and their outer shells, and make sure the bearings have no scars or crude points left by machinery processing. Inside outer shells on no occasions should grit and cutting scraps of grinding powder type (SiC, A12O3) be found.
Next examine the size, shape and processing quality of the bearings and their outer shells to see whether they are consistent with those in the blueprint.
Measure the diameter size of the bearings and their outer shells in several places. Examine carefully the round angle size of the bearings and of their outer shells and the perpendicular degree of the shield.
Before bearing installation, daub the machinery oil on assembly surface of the qualified bearings and of their outer shells
bearing installation methods
Bearing installation methods vary with the different types and assembly conditions of the bearings.
Since for most of the bearings the rollers rotate, inner shells and outer shells can use respectively over-filled assembly and gap assembly. For outer shells rotation, outer shells adopt over-filled assembly.
bearing installation methods for over-filled assembly have mainly the following types
(1) pressing installation
Pressing installation ordinarily uses pressure machines, also can use nuts, and in poor conditions can adopt installation by hand.
(2) hot cover installation
Heat the bearings in oil to make them swell, then install them in the hot covers on the rollers. This method can make bearings avoid unnecessary external force and finish the practice in short time.
points for attention in heating :
1) Generally do not heat in temperature above 100 ≧ .
2) Bearings are not allowed to touch the bottom of oil trough.
In addition, hot cover installation can also use induction heating devices to heat the bearings so as to make them swell and then install on the rollers.
Bearings should be disassembled in the case of periodical examination and components replacements. Usually rollers and bearing boxes continue to be used, and so are bearings. Thus, structure design should take into account that when disassembled, bearings, rollers, bearing boxes and other components should not be harmed. Meanwhile, appropriate disassembly tools should be prepared. When static assembly cover disassembled, pulling force can only be put on the covers and not through rolling entity to drag covers.
keep bearing maintenance practice (periodical check) seriously and conscientiously in order to make best use of the bearings
Through proper periodical check discover troubles at an early time and prevent accidents from happening, which are important for enhancing productivity and economy degree.
When disassembling bearings, one should record the outside appearance of the bearings by taking photos. Besides, ascertain the remaining lubricant quantity and sample the lubricant, then rinse the bearings.
a Bearing rinse includes rough rinse and fine rinse. Metal net rack can be put at the bottom of the container used in the rinse.
b In rough rinse, use brushes to remove lubricant and other sticky substance on the bearings in the oil. Be careful that at this moment if bearings are revolved in the oil, the rolling surface will be damaged by the substance in the oil.
c In fine rinse, slowly revolve the bearings in the oil with great care.
The commonly used rinse powders are neutral non-watery diesel oil or kerosene, and also mild alkali liquid according to requirements. Whatever rinse power is used, it should be always kept clean by filtering.
After rinse, immediately daub anti-rust or anti-grease on the bearings.
2 check and judgment
In order to judge whether the disassembled bearings can be used again, their size sophistication degree, rotation sophistication degree, inner gaps, assembly surface, rolling surface, retainers and airtight rings should be checked carefully.
For the check results, staffs familiar with or proficient in bearings can decide on it.
Judgment standards vary with the machinery quality, importance degree and time for periodical check of the bearings.For bearings with the following damages, they should not be used again and should be replaced.
1) the crack and flaw of bearing components
2) Entity rolling surface removed from the rolling channel surface
discovery methods for bearing troubles
Without disassembly check whether or not the bearings in work are in trouble can be discovered or predicted. This is quite important for enhancing the productivity and economy degree.
main discovery methods are as follows:
1) discovery through sounds of bearings
Discovery through bearing sounds requires rich experiences. Sufficient training is needed to identify bearing sounds from non-bearing sounds. Thus, persons should be chosen specially for this task. Put hearing devices or hearing sticks on bearing outer shells can clearly hear bearing sounds.
2) discovery through working temperature
This method is comparative in nature, confined to situations with no or slight moving state changes. Thus the temperature should be continuously recorded. When bearing trouble occurs, not only temperature will be rise, also irregular changes will occur.
3) discovery through lubricant state
Sample and analyze the lubricant. Judge through bearings' filthy degree to determine whether or not foreign substance or metal powder is mixed with the bearings. This method is especially effective for bearings unable to be closely examined and for large sized bearings.