1:Defination
Four-point contact ball bearing is a separation of bearings, it can be said of a two-way bearings can withstand axial load of angular contact ball bearings.The inner and outer raceway is peach-type section, when no load or a pure radial load, the balls and rings appear as four-point contact, which is the origin of the name; when only pure axial load When the two steel balls and rings become exposed, can withstand a two-way axial load. Four-point contact ball bearings can withstand torque loads, both the single row angular contact ball bearings and double row angular contact ball bearings features. Only four-point contact ball bearings in contact to ensure the formation of two normal work. It is generally applied to those of pure axial load or axial load large synthetic loads where contact was two, four point contact ball bearings high speed limit, but also for those high-speed operation of the occasion.
Four-point contact ball bearing is a separation of bearings, it can be said of a two-way bearings can withstand axial load of angular contact ball bearings.The inner and outer raceway is peach-type section, when no load or a pure radial load, the balls and rings appear as four-point contact, which is the origin of the name; when only pure axial load When the two steel balls and rings become exposed, can withstand a two-way axial load. Four-point contact ball bearings can withstand torque loads, both the single row angular contact ball bearings and double row angular contact ball bearings features. Only four-point contact ball bearings in contact to ensure the formation of two normal work. It is generally applied to those of pure axial load or axial load large synthetic loads where contact was two, four point contact ball bearings high speed limit, but also for those high-speed operation of the occasion.
2:Feature
a.Four-point contact ball bearings are separable structure, a single bearing can replace the front or the back of the portfolio combined angular contact ball bearings.
b.Can bear radial load, two-way axial load, to limit the axial displacement in both directions, but the specifications than the current golf ball bearings double row angular contact axial occupy less space.
c.Four-point contact ball bearings and other ball bearing, radial clearance when the same, the axial clearance small, high speed limit.
d.Four-point contact ball bearings for under pure axial load or axial load to mainly axial, radial joint load. As a dual semi-inner (or outer), put the ball in number and have greater carrying capacity.
Under normal working conditions, such bearings to withstand the axial load in any direction, can form a contact angle, ball and inner and outer raceway at the point of the contact, avoid contact with large sliding occurred. Therefore, the bearings should not be subject to radial force and load-based
Slewing Bearing / Slewing Ring Bearing
a.Four-point contact ball bearings are separable structure, a single bearing can replace the front or the back of the portfolio combined angular contact ball bearings.
b.Can bear radial load, two-way axial load, to limit the axial displacement in both directions, but the specifications than the current golf ball bearings double row angular contact axial occupy less space.
c.Four-point contact ball bearings and other ball bearing, radial clearance when the same, the axial clearance small, high speed limit.
d.Four-point contact ball bearings for under pure axial load or axial load to mainly axial, radial joint load. As a dual semi-inner (or outer), put the ball in number and have greater carrying capacity.
Under normal working conditions, such bearings to withstand the axial load in any direction, can form a contact angle, ball and inner and outer raceway at the point of the contact, avoid contact with large sliding occurred. Therefore, the bearings should not be subject to radial force and load-based
Slewing Bearing / Slewing Ring Bearing
Slewing bearing is a kind of special structure of large bearings which can withstand large axial load, radial load and overturning moment, integrating supporting, rotation, transmission, fixed and other functions. Under normal circumstances, slewing bearings have their own mounting holes, lubricants and seals, which can meet various of host need under different working conditions; On the other hand, slewing bearings themselves are compact, easy to guide the rotation,easy installation and easy maintenance, so they widely used in material handling equipments, mining machines, construction machinery, port machinery, wind power generation, medical equipments, radar and missile launchers and other large rotating devices.
According to different structure, slewing bearing can be divided into the following types:
1, the four-point contact ball slewing bearing
2, double row four-point contact ball slewing bearing
3, crossed cylindrical roller slewing bearings
4, three-row cylindrical roller combined slewing bearing
1, the four-point contact ball slewing bearing
2, double row four-point contact ball slewing bearing
3, crossed cylindrical roller slewing bearings
4, three-row cylindrical roller combined slewing bearing
Four-point contact ball slewing bearing
Four-point contact ball slewing bearing is a separative bearings, it also can be called angular contact ball bearings which can withstand two-way axial load, whose inner and outer ring raceway is a peach shaped cross section, when no load or a pure radial load role, balls and rings appear as four-point contact, which is the origin of the name; when only pure axial loading, the steel ball and the rings became two contacts can withstand axial load in both directions. Four-point contact ball slewing bearings can withstand torque loads, both the single row angular contact ball bearings and double row angular contact ball bearings features. Only four-point contact ball bearings in contact to ensure the formation of two normal work. It is generally applied to those of pure axial load or axial load large synthetic loads where contact was two, four point contact ball bearings high speed limit, but also for those high-speed operation of the occasion.
Slewing bearing applications
Slewing bearing are widely used in lifting machinery, mining machinery, construction machinery, port machinery, shipbuilding, machinery, precision machinery radar and missile launchers and other large rotating device.
1. Wind generator
Tower and yaw bearings are installed in the junction of tower and the cockpit; pitch bearings are installed in each blade root and hub joints. Each wind turbine equipment use three sets pitch bearings and a set of yaw bearing. pitch bearing ring material select 42CrMo, treatment with the overall quenching, raceway select surface-hardening. As the wind turbine yaw, pitch bearing’s force is complex and bearings withstand large shock and vibration, therefore, required bearings to withstand both the impact and greater loads. Host wind turbine life requirements of 20 years, bearing the cost of installing large, thus requiring yaw, pitch bearing life have reached 20 years. Bearing rings matrix hardness is 240HB-280HB, so it is able to withstand shocks but no plastic deformation, meanwhile raceway surface quenching hardness reach to 55HRC-62HRC, also can increase the contact fatigue life, thus ensuring long life bearing requirements.
2. Marine Crane
In general, marine crane use double-row different diameter ball, four-point contact ball, three-row roller inner gear structure slewing bearings. According to the different carrying capacity, three-row roller slewing bearings are usually used for heavy-duty cranes, four-point contact ball slewing bearing and double row different diameter ball for light crane.
As cranes working environment is -20 ° C-+45 ° C, this kind of bearing require high material mechanical properties.
3. Offshore crane
According to different requirement for carrying capacity, offshore crane usually use four-point contact ball slewing bearing and three-row roller inner gear slewing bearing.
Slewing bearing used for offshore platform crane have special material requirements: material mechanical properties should be able to guarantee the limit load factor of safety., forging sample Charpy impact test can achieve to average 42J @ -20 ° C or 27J @ -40 ° C, bearing products to the Classification Society certification.
4. Port mobile crane
Port cranes usually use internal or external gear, 4 meters in diameter three rows roller slewing bearings to withstand high overturning moment.
5. Stacker-reclaimer
Slewing bearing stacjer-reclaimer usually use is ball column combined type, three-row roller and cross-roller, the majority diameter over 3 meters. Due to poor working conditions, dusty, these bearings have high load capacity, long life and good sealing performance feature.
Slewing bearing stacjer-reclaimer usually use is ball column combined type, three-row roller and cross-roller, the majority diameter over 3 meters. Due to poor working conditions, dusty, these bearings have high load capacity, long life and good sealing performance feature.
6. Ferris wheel
Usually use four-point contact ball slewing bearing, diameter 4100mm, thickness 85mm.
7.ship unloaders
Usually use three rows of outer roller tooth structure, about 4 meters in diameter
8. Tower crane
Usually use small size four-point contact ball bearings or double-row ball, diameter not more than 2 meters
Usually use small size four-point contact ball bearings or double-row ball, diameter not more than 2 meters
9. Radar antenna
Usually use three-row roller slewing bearing, slow rotation
10. Shield
Diameter from 2.5 meters to 6 meters, some larger diameter, these bearings work in very poor conditions, bearing a large load, corrosion resistance, short life.
11. Ladle turret in steel plant
Usually these bearing are three-row roller slewing bearings, because work in the dust and high temperature conditions, so s have high demands for maintain, grease and seal.
12. Engineering machinery
Usually use small size four-point contact ball bearings or double-row ball, diameter not more than 2 meters