2018年9月29日星期六
How to grasp the best time for bearing oil change
Affirmative answers are not acceptable as to whether or not the grease can be used indefinitely. Because of the excessive use of grease, it is a lot of damage to the bearing.
Grease has a good effect on the bearing. It has good adhesion, wear resistance, temperature resistance, rust resistance and lubricity. It can improve high temperature oxidation resistance, delay aging, dissolve carbon deposits and prevent metal abrasion. Condensation with oil to improve the wear resistance, pressure resistance and corrosion resistance of the machine.
However, the more the grease is filled, the greater the friction torque. With the same filling amount, the friction torque of the sealed bearing is larger than that of the open bearing. After the grease filling amount is equivalent to 60% of the internal space of the bearing, the friction torque is no longer significantly increased. This is because most of the grease in the open bearing has been extruded, and the grease in the sealed bearing has also been lost.
As the filling amount of the grease increases, the temperature rise of the bearing increases linearly, and the same filling amount, the temperature rise of the sealed bearing is higher than that of the open bearing. It is generally believed that the grease filling capacity of sealed rolling bearings should not exceed 50% of the internal space.
In general, the lubrication plan for bearings is based on time. Equipment suppliers typically develop lubrication plans based on operating time. Also, equipment suppliers often add guidance on the amount of lubricant during their maintenance planning. For the staff, short-term lubricant replacement is very common, and often more grease is added.
For lubricated bearings, there is a fixed concept of prevention that keeps the equipment operating properly without the bearings being shut down due to drying and collapse. However, we have to balance the need to maintain lubrication and hunger and a lot of over-lubrication. If the oil change is too small, the bearing will be scrapped in advance; if the oil is changed too much, the bearing will be in trouble or damage the power coil and winding wire for a long time.
Analysis of bearing accuracy grade
The accuracy is increased from the 0th level in order, and is sufficient for the general purpose 0 level, but when used for special conditions or occasions, it requires 5 levels or higher.
Although the above accuracy levels are based on the ISO standard, their names are different in national standards.
Dimensional accuracy (items related to shaft and housing installation)
1. Allowable deviation of inner diameter, outer diameter, width and assembly width
2. Allowable deviation of the diameter of the compound circle and the diameter of the outer complex circle in the roller group
3, the allowable limit value of the chamfer size
4, the allowable variation of the width
Rotation accuracy (items related to the rotation of the rotating body)
1. Allowable radial runout and axial runout of the inner and outer rings
2, the inner ring allows lateral runout
3. Allowable variation of the inclination of the outer diameter surface
4. Allowable variation of the thickness of the thrust bearing raceway
5. Allowable deviation and allowable variation of tapered bore
Although the above accuracy levels are based on the ISO standard, their names are different in national standards.
Dimensional accuracy (items related to shaft and housing installation)
1. Allowable deviation of inner diameter, outer diameter, width and assembly width
2. Allowable deviation of the diameter of the compound circle and the diameter of the outer complex circle in the roller group
3, the allowable limit value of the chamfer size
4, the allowable variation of the width
Rotation accuracy (items related to the rotation of the rotating body)
1. Allowable radial runout and axial runout of the inner and outer rings
2, the inner ring allows lateral runout
3. Allowable variation of the inclination of the outer diameter surface
4. Allowable variation of the thickness of the thrust bearing raceway
5. Allowable deviation and allowable variation of tapered bore
2018年9月27日星期四
Advantages of hybrid ceramic bearings
(1), high temperature resistance, ceramic ball thermal expansion coefficient is small, in the high temperature environment will not cause the bearing ball to expand due to temperature, which greatly improves the use temperature of the entire bearing, the temperature of ordinary bearings is about 160 degrees, ceramic ball Can reach more than 220 degrees.
(2), high speed, ceramic ball has oil-free self-lubricating properties, ceramic ball friction coefficient is small, so ceramic ball bearings have a very high rotational speed. The statistics of ceramic ball bearings are more than 1.5 times the speed of the general bearing.
(3), long life, ceramic ball can be added without any grease, which means that even if the grease is dry, the bearing can still operate, thus avoiding the premature bearing damage caused by the dry grease in the ordinary bearing. According to us The test and some customer feedback use the ceramic ball after the bearing has a service life of 2-3 times that of ordinary bearings.
(4) Insulation. Bearings made of ceramic balls can insulate the inner and outer rings of the bearing. Because the ceramic ball is an insulator, the ceramic ball can be used between the inner and outer rings of the bearing to achieve the effect of insulation. Can be used in a conductive environment. This is also the biggest advantage of hybrid ceramic bearings.
(2), high speed, ceramic ball has oil-free self-lubricating properties, ceramic ball friction coefficient is small, so ceramic ball bearings have a very high rotational speed. The statistics of ceramic ball bearings are more than 1.5 times the speed of the general bearing.
(3), long life, ceramic ball can be added without any grease, which means that even if the grease is dry, the bearing can still operate, thus avoiding the premature bearing damage caused by the dry grease in the ordinary bearing. According to us The test and some customer feedback use the ceramic ball after the bearing has a service life of 2-3 times that of ordinary bearings.
(4) Insulation. Bearings made of ceramic balls can insulate the inner and outer rings of the bearing. Because the ceramic ball is an insulator, the ceramic ball can be used between the inner and outer rings of the bearing to achieve the effect of insulation. Can be used in a conductive environment. This is also the biggest advantage of hybrid ceramic bearings.
How to choose the correct lathe rolling bearing?
1 Size, direction and nature of the load The ball bearing is suitable for withstanding light loads and the roller bearing is suitable for withstanding heavy loads and shock loads. When the rolling bearing is subjected to pure axial load, thrust bearing is generally used; when the rolling bearing is subjected to pure radial load, deep groove ball bearing or short cylindrical roller bearing is generally used; when the rolling bearing is subjected to pure radial load, there is still little For axial load, deep groove ball bearings, angular contact ball bearings, tapered roller bearings and self-aligning balls or spherical roller bearings are available. When the axial load is large, angular contacts with large contact angles are available. Ball bearings and tapered roller bearings, or the combination of radial and thrust bearings, are particularly suitable for very high axial loads or particularly large axial stiffness.
2 The allowable speed varies greatly depending on the type of bearing. In general, bearings with low friction and low heat generation are suitable for high speeds. The design is designed to work with rolling bearings below their limit speed.
3 When the rigid bearing is under load, the bearing ring and the rolling element will be elastically deformed at the contact point. The deformation amount is proportional to the load, and the ratio determines the rigidity of the bearing. Generally, the rigidity of the bearing can be improved by pre-tightening of the bearing; in addition, in the design of the bearing support, the bearing rigidity can be improved by considering the combination and arrangement of the bearings.
4 Self-aligning performance and installation error After the bearing is loaded into the working position, the installation and positioning are often poor due to manufacturing errors. At this time, the bearing often suffers from excessive load due to the degree of fishing and thermal expansion of the shaft, causing early damage. Self-aligning bearings can overcome the defects caused by installation errors and are suitable for such applications.
5 Mounting and dismounting tapered roller bearings, needle bearings, etc., belonging to the type of bearing that can be separated between the inner and outer rings (so-called separate bearings), easy to install and disassemble.
6 Marketability Even if it is a horizontal lathe bearing listed in the catalogue, there is no market for sales; on the contrary, some bearings not listed in the catalogue are produced in large quantities. Therefore, it should be clear whether the bearings used are readily available.
2 The allowable speed varies greatly depending on the type of bearing. In general, bearings with low friction and low heat generation are suitable for high speeds. The design is designed to work with rolling bearings below their limit speed.
3 When the rigid bearing is under load, the bearing ring and the rolling element will be elastically deformed at the contact point. The deformation amount is proportional to the load, and the ratio determines the rigidity of the bearing. Generally, the rigidity of the bearing can be improved by pre-tightening of the bearing; in addition, in the design of the bearing support, the bearing rigidity can be improved by considering the combination and arrangement of the bearings.
4 Self-aligning performance and installation error After the bearing is loaded into the working position, the installation and positioning are often poor due to manufacturing errors. At this time, the bearing often suffers from excessive load due to the degree of fishing and thermal expansion of the shaft, causing early damage. Self-aligning bearings can overcome the defects caused by installation errors and are suitable for such applications.
5 Mounting and dismounting tapered roller bearings, needle bearings, etc., belonging to the type of bearing that can be separated between the inner and outer rings (so-called separate bearings), easy to install and disassemble.
6 Marketability Even if it is a horizontal lathe bearing listed in the catalogue, there is no market for sales; on the contrary, some bearings not listed in the catalogue are produced in large quantities. Therefore, it should be clear whether the bearings used are readily available.
2018年9月26日星期三
ZRB72X100 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
ZRB75X110 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
ZRB75X120 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
2018年9月25日星期二
ZRB80X160 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
ZRB80X80 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
ZRB80X85 Cylindrical rollers
| Diameter | ||
| Length | ||
| Chamfer dimension |
| Mass, 1000 pieces |
ZSL192319-TB-XL Cylindrical roller bearings
| Axial displacement |
| Mass | ||
| Basic dynamic load rating, radial | ||
| Basic static load rating, radial | ||
| Fatigue limit load, radial | ||
| Limiting speed | ||
| Reference speed |
2018年9月18日星期二
QJ312-XL-MPA Four point contact bearings
| Contact angle |
| Mass | ||
| Basic dynamic load rating, radial | ||
| Basic static load rating, radial | ||
| Fatigue limit load, radial | ||
| Limiting speed | ||
| Reference speed |
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