Product Introduction

The 31300 series stands out among single-row tapered Roller Bearings for its large contact angle—ranging from approximately 24° to 28°. Offering superior axial load-carrying capacity compared to standard-angle series, it is specifically engineered for applications subject to significant axial forces, such as differential drive pinions and helical gear shafts.

Single-row Tapered Roller Bearings are among the most widely used rolling bearings in industry. They feature an inner ring with a tapered raceway and a large guide flange, a cup-shaped outer ring with a tapered raceway, and a single row of tapered rollers positioned between them. The geometry is designed so that the apexes of the tapered surfaces converge at a single point on the bearing axis, ensuring pure rolling motion for the rollers. As separable bearings, the inner ring assembly and outer ring can be mounted independently. They are capable of simultaneously supporting radial loads and unidirectional axial loads; typically, they are installed in opposing pairs to provide axial location in both directions. They find extensive application in sectors such as automotive, construction machinery, mining, and gear reducers.

Series Positioning

The 31300 series bears the diameter series code "13" and is distinguished primarily by its large contact angle design. Notably, the 31300 series shares identical external dimensions with the 30300 series—matching in bore diameter, outer diameter, and width—with the contact angle being the only difference. This allows users to upgrade to the higher axial load capacity of the 31300 series without altering the mounting space. 

Key Features

High Axial Load Capacity: Features a large contact angle (24° to 28°), providing axial load capacity more than double that of the 302 series.

Dimensional Compatibility: External dimensions are identical to the 30300 series, allowing for direct interchangeability and upgrades.

Slightly Reduced Radial Load Capacity: The large contact angle shifts load distribution toward the axial direction, resulting in a radial load capacity slightly lower than that of the 30300 series.

Lower Speed Limits: Increased sliding friction at the large end of the rollers results in lower limiting speeds compared to standard contact angle series.

Dimensional Parameter Table

The basic dimensions of WGHB Tapered Roller Bearings are listed in the dimensional data sheet

Single Row Tapered Roller Bearings: Most basic and widely used tapered bearing. Usually fitted as one of an opposing pair. During equipment assembly, can be set to the required clearance (end play) or preload condition to optimize performance. 

Single row (Type 30000): The most common type; primarily accommodates combined loads with a dominant radial component.

Inner diameter size range: 20mm~1270mm

Outer diameter range: 40mm~1465mm

Width size range: 15mm~240mm

Double Row Tapered Roller Bearings: Double row tapered bearing arrangements offer increased load capacity over single types.

Double row (Type 350000): Capable of supporting radial loads as well as bidirectional axial loads; commonly used in applications such as passenger car wheel hubs.

Inner diameter size range: 38mm~1560mm

Outer diameter range: 70mm~1800mm

Width size range: 50mm~460mm

Four Row Tapered Roller Bearings: Combine the inherent high-load, radial/thrust capacity and direct/indirect mounting variables of tapered roller bearings into assemblies of maximum load rating in a minimal space.

Four row (Type 380000): Features higher load-carrying capacity and is primarily used in heavy machinery, such as rolling mills.

Inner diameter size range: 130mm~1600mm

Outer diameter size range: 200mm~2000mm

Width size range: 150mm~1150mm

Common Suffixes

J: Pressed steel cage

B / D: Designations used by some manufacturers to indicate large contact angle variants

P5 / P4: Precision classes (for high-precision gearbox applications)

C3 / C4: Large internal clearance groups

W33: Outer ring with lubrication groove and oil holes

Quick Reference for Common Models

31306  30×72×20.75  Small differentials, agricultural machinery bevel gears

31308  40×90×25.25  Automotive final drive pinion shafts

31310  50×110×29.25  Commercial vehicle differentials, helical gear shafts

31312  60×130×33.5  Heavy-duty axles, construction machinery gearboxes

31314  70×150×38  Large speed reducer bevel gear shafts

31316  80×170×42.5  Metallurgical equipment, mining machinery gear shafts

Application Scenarios

Automotive Final Drive: The 31300 series is the standard bearing for differential drive bevel gears (pinion shafts); the large axial forces generated by bevel gear meshing are precisely what the 31300's large contact angle design is engineered to handle. Models ranging from 31308 to 31314 cover applications from passenger cars to commercial vehicles. Industrial Gearboxes: For shaft ends subject to significant axial forces—such as those with helical gears, bevel gears, or worms—the 31300 series effectively handles axial load components, eliminating the need for additional thrust bearings.

Construction Machinery: Commonly used in applications such as excavator swing mechanisms and loader drive axle bevel gear transmissions (specifically models 31310 through 31316).

Mining Equipment: Used for crusher gear shafts and conveyor drive bevel gears, where operations involve high axial loads.

Key Differences

The 31300 series and the 30300 series share identical external dimensions, a highly practical feature for bearing selection. The only difference lies in the contact angle: the 30300 series has an angle of approximately 12° to 15° (predominantly radial load capacity), while the 31300 series has an angle of approximately 24° to 28° (predominantly axial load capacity). If axial forces increase and the 30300 series proves insufficient, the 31300 series can be installed as a direct replacement without modifying shaft or housing bore dimensions.

Selection Recommendations

The 31300 series is suitable for applications involving high axial loads and moderate radial loads, particularly at the ends of bevel gear and helical gear shafts. If axial loads are low, the 30300 series is more cost-effective; if axial loads are extremely high and a wide-series heavy-duty bearing is required, the 33200 series should be considered.