Double row tapered roller bearings can simultaneously withstand radial and axial combined loads, mainly radial loads, and can withstand bidirectional axial loads. Their specific force characteristics and structural design are as follows:
1. Force Characteristics Analysis
Radial and Axial Combined Load
Double row tapered roller bearings can transmit radial and axial forces simultaneously through the contact design between tapered rollers and inner and outer raceway. Its load-bearing capacity depends on the outer raceway angle (contact angle α):
The larger the contact angle (usually 10 ° to 30 °), the stronger the axial load bearing capacity.
Formula relationship: The axial load capacity is positively correlated with the contact angle. As the contact angle increases, the proportion of axial force distribution by the bearing increases.
.Bearing bidirectional axial loads
The double row structure is symmetrically arranged with two rows of rollers, which can limit the bidirectional axial displacement of the shaft relative to the bearing seat.
. For example, in the front wheel hub of a car, double row tapered roller bearings can simultaneously withstand the forward axial force during vehicle braking and the reverse axial force during steering. In heavy machinery such as rolling mills, bearings need to withstand the bi-directional axial thrust transmitted by the rolling mill rolls.Torque Load Adaptation
In scenarios such as railway freight cars and wind power equipment, double row tapered roller bearings need to withstand bending moment loads (such as the tilting moment when a train turns).
. Its structure optimizes the contact line between the rollers and the raceway, reduces stress concentration, and enhances its anti overturning ability.2. Influence of structural design on stress
Spacer adjustment mechanism
A spacer is installed between the two inner (or outer) rings of a double row bearing, and the clearance adjustment can be achieved by changing the thickness of the spacer.
Clearance adjustment: eliminates assembly clearance and ensures the accuracy of bearing operation.
. Pre interference control: Apply pre tension force to increase stiffness and reduce vibration.Roller and raceway optimization
Edge design: Optimize the surface smoothness of the edge, promote the formation of lubricant film, and reduce friction and wear.
.Contact Curve: Using logarithmic contact curve profiles (such as SKF Explorer bearings) to reduce roller end stress and improve tolerance for shaft offset.
.Separable Structure
The outer ring (or inner ring) of a double row tapered roller bearing is an integral structure, with the small end faces of the two inner rings (or outer rings) being close and separated by a spacer in the middle.
. This design is easy to install and maintain, while ensuring even distribution of loads.III. Typical Application Scenarios
Automotive Industry
Front Wheel Hub: Double row tapered roller bearings bear radial loads (such as vibrations caused by uneven road surfaces) and axial loads (such as lateral forces during steering) during vehicle operation.
.Transmission system: In the differential, the bearings need to simultaneously transmit engine torque (radial force) and axial force generated by gear meshing.
.Heavy Machinery
Rolling Mill: In cold and hot rolling mills, double row bearings bear the enormous radial pressure and axial thrust transmitted by the rolling rolls, ensuring rolling accuracy.
. Mining equipment: In equipment such as crushers and excavators, bearings need to withstand the composite load generated by material impact.Railway and wind power
Railway freight cars: capable of bearing cargo loads ranging from 25t to 40t on the axle, while also adapting to the dynamic torque of high-speed train operation.
. Wind turbine main shaft: In wind turbines, bearings need to withstand the radial wind load and axial thrust transmitted by the blades to ensure stable operation of the main shaft.