Classification and application scenario analysis of double row tapered roller bearings
1. Model classification
Double row tapered roller bearings can be divided into the following two categories according to the arrangement of rollers and the inner/outer ring structure:
Classification according to the arrangement of rollers
"Back to Back" type (TDO type): Two rows of rollers are arranged back-to-back, the outer ring is an integral structure, and the inner ring is composed of two single row inner rings separated by a middle partition ring. This design can withstand bidirectional axial loads and has high rigidity, making it suitable for scenarios with large axial forces.
"Face to face" type (TDI type): Two rows of rollers are arranged face to face, the inner ring is an integral structure, and the outer ring is composed of two single rows of outer rings, separated by a middle partition ring.
. Its axial load-bearing capacity is slightly lower than that of the "back-to-back" type, but its structure is compact and suitable for space constrained scenarios.Classified by inner/outer ring structure
Double inner ring type (TDO type): The outer ring is an integral structure, and the inner ring is composed of two single row inner rings. The clearance and pre fit are adjusted by a middle ring.
.Double outer ring type (TDI type): The inner ring is an integral structure, and the outer ring is composed of two single row outer rings, which are also adjusted for clearance and pre interference through a middle ring.
.II. Core Features
High Load Capacity
Double row tapered roller bearings can withstand both radial and bidirectional axial loads simultaneously, making them suitable for heavy-duty conditions.
. Its rated dynamic load is significantly increased compared to single row bearings, for example, in railway freight car bogies, the single axle load can reach 30 tons. Adjustable clearanceBy changing the thickness of the spacer ring, the bearing clearance or pre interference can be precisely adjusted to meet different working conditions.
. The clearance has been adjusted to the standard range when leaving the factory, and users do not need to make additional adjustments, but it can be customized for special needs.Bi directional axial displacement limitation
Bearings can limit the bi-directional axial displacement of the shaft or housing within the axial clearance range, ensuring stable operation of the equipment.
. For example, in a rolling mill, axial movement of the rolling mill rolls can be prevented to improve rolling accuracy.Structural adaptability
"Back to back" type: high rigidity, suitable for scenarios that withstand large axial forces, such as lifting equipment and mining machinery.
."Face to face" type: compact structure, suitable for space limited scenarios such as gearboxes and motors.
.III. Application Scenarios
Railway Vehicles
Freight Car Bogie: Adopting double row tapered roller bearings (such as TDO type), it can withstand the heavy load transportation needs of trains, with a single axle load of up to 30 tons and a service life of over 800000 kilometers.
.EMU/high-speed rail bogies: Some high-speed trains use double row bearings at the drive shaft end to balance bidirectional forces and improve operational stability.
.Heavy Machinery
Rolling Mill: Four row tapered roller bearings are used for the working rolls to withstand combined radial and axial loads at low and medium speeds;
; Double row bearings are used to support rollers, providing high rigidity and load-bearing capacity. Mining machinery: In tunnel boring machines and crushers, double row bearings bear impact loads and bidirectional axial forces to ensure reliable operation of the equipment.Industrial transmission equipment
Gearbox: Double row bearings (such as TDI type) are used for high-speed gear shafts to withstand the radial and axial forces generated by gear meshing, reducing vibration and noise.
.Lifting equipment: In the drum bearings of the crane, double row bearings bear lifting loads and braking impacts, extending their service life.
.Other fields
Agricultural machinery: In large combine harvesters and tractors, double row bearings are used to drive shafts and gearboxes, adapting to harsh working conditions.
. Plastic machinery: In injection molding machines and extruders, double row bearings bear the radial force and melt pressure generated by screw rotation, ensuring extrusion stability.