In the automotive field, bearings are the core components that ensure power transmission, driving stability, and safety. Among them, tapered roller bearings and wheel hub bearings play a key role in different scenarios due to their unique structures and performance. The following provides a detailed explanation of the structural characteristics, application scenarios, core roles, and development trends of both:
1、 Conical roller bearings: the "power transmission hub" that carries composite loads
Conical roller bearings are a classic type of rolling bearing, with a core structure consisting of an inner ring (shaft ring), an outer ring (race ring), conical rollers, and a cage. Due to the conical shape of the rollers, the raceway generatrix of the inner and outer rings is a conical surface. This design allows it to simultaneously withstand radial loads (forces perpendicular to the axis, such as vehicle weight) and axial loads (forces parallel to the axis, such as forces generated by gear meshing, braking, or steering), making it a key component in automobiles that can withstand composite loads.
1. Core application scenarios
Conical roller bearings are widely used in the transmission and steering systems of automobiles, especially in areas that require torque transmission and complex load bearing
Drive axle (main reducer and differential)
The drive axle is a key component that transmits engine power to the wheels, and the active bevel gear, driven bevel gear, and differential housing support of the main reducer all rely on tapered roller bearings. For example:
Active bevel gears are usually installed back-to-back or face-to-face with two tapered roller bearings (such as front wheel drive type), which bear the axial thrust generated by gear meshing (due to the axial component force generated by bevel gear transmission) and radial force (the radial component force of gear self weight and torque transmission);
The differential housing is supported inside the drive axle housing through tapered roller bearings, ensuring stable rotation of the differential when transmitting power, while also bearing the radial load feedback from the wheels.
Connection between steering knuckle and wheel hub
When a car turns, the steering knuckle needs to drive the wheels to rotate flexibly, while bearing the radial load (body weight) and axial load (lateral force during turning) transmitted by the wheels. Conical roller bearings provide precise guidance for wheel hub rotation by fixing the inner ring to the wheel hub and the outer ring to the steering knuckle, ensuring smooth and stable steering. For example, the front axle steering knuckle of traditional trucks often uses a combination of double row tapered roller bearings to enhance their load-bearing capacity.
Manual transmission and transfer case
The input shaft and output shaft of manual transmission, as well as the power output shaft of the transfer case of four-wheel drive models, need to simultaneously withstand torque (power transmission) and radial load (radial force of gear meshing). Due to its compact structure and composite load-bearing capacity, tapered roller bearings have become the preferred choice for supporting such shaft systems. For example, the end of the transmission output shaft is supported by tapered roller bearings to ensure stable power transmission to the drive shaft.
Core features and advantages
High composite bearing capacity: Both radial and axial load bearing capacities are superior to deep groove ball bearings, suitable for the dual needs of "power transmission+load support" in automotive transmission systems;
Compact structure: The conical design of the tapered roller enables high utilization of the internal space of the bearing, enabling strong load-bearing capacity within the limited space of the automotive chassis;
Adjustable preload: By adjusting the axial clearance (such as washers or nuts), the bearing rigidity can be optimized, vibration and noise can be reduced, and the service life can be extended.
2、 Wheel hub bearing: the "core support unit" for wheel rotation
Wheel hub bearings are key components of the automotive driving system, directly installed between the wheel hub and the axle (or steering knuckle). Their core function is to support the weight of the wheel, provide precise guidance for the rotation of the wheel hub, and withstand radial loads (body weight), axial loads (steering/braking/lateral force), and impact loads (road bumps) during vehicle operation.
Modern wheel hub bearings have evolved from early split type bearings to integrated "wheel hub units", which can be divided into three generations according to structural evolution:
First generation: Split type, consisting of two sets of tapered roller bearings or deep groove ball bearings combined, requiring manual adjustment of preload;
Second generation: equipped with inner/outer ring flanges, simplified installation, but still requires pre tightening adjustment;
The third generation: fully integrated, with built-in flange (directly connected to the wheel hub or steering knuckle), no pre tightening adjustment, greatly improved integration and reliability, is currently the mainstream.