As an early technological solution, the characteristics of the first generation of automotive wheel hub bearings can be summarized as the following core advantages and limitations:
1. Structural design: Split type double bearing combination
Components
Composed of an outer ring, two inner rings, steel balls, and a retaining structure, forming a double row angular contact ball bearing or double row tapered roller bearing structure. This design shortens the payload spacing and improves structural stability through back-to-back combination of inner rings.
Pre tightening and installation optimization
Pre tightening force control: The initial bearing clearance is pre-set to ensure that the pre tightening load after installation is within the specified range, without the need to use spacers to adjust the pre tightening load on the automotive assembly line, simplifying the assembly process.
.High precision machining: To ensure pre tightening accuracy, the outer race raceway needs to be synchronously ground, and the inner race raceway is machined using a high-precision rotary forming shaper, with extremely high requirements for groove center distance accuracy.
.Sealing Performance
Comes with a double lip rubber seal ring and dust cover, with a protection level of IP66 (dust and splash proof), effectively preventing mud, dust, and water vapor from entering and extending the bearing life.
. But the sealing design cannot cope with water immersion conditions, and long-term water immersion may lead to seal failure.2. Performance characteristics: Load bearing and stability
Load capacity
Rated dynamic load: 30-80kN, suitable for vehicle models with axle loads of 0.5-2 tons, meeting the light load requirements of passenger cars.
. Limit speed: ≤ 3000r/min, matched with a maximum speed of 180km/h, suitable for economy cars and non drive wheels.Stability and Durability
Compact Structure: By optimizing the processing technology of raceway convexity (such as conical raceway convexity), stress concentration is reduced and fatigue life is improved.
. Low vibration noise: Adopting reinforced tapered rollers and high-precision machining technology to reduce vibration and noise during operation.III. Maintenance and Cost: Economy Priority
Lubrication Plan
Lithium based grease filling is used, and regular maintenance is required (grease is replenished every 50000 kilometers), resulting in high maintenance costs and workload.
. But compared to the traditional combination of two sets of bearings, the first generation bearings have reduced the number of lubrication points through integrated design.Cost advantage
Single set price: 40% lower than the second-generation integrated solution, with high maintenance convenience (the outer or inner ring can be replaced separately).
.Application scenarios: Widely used in economy passenger cars (such as Toyota Corolla, early models of Volkswagen Golf) and light commercial vehicles (such as Japanese light truck rear wheels), to meet the demand of cost sensitive markets.
.4. Limitations: Challenges under technological iteration
Complex assembly process
During online assembly, it is necessary to press fit the bearing inner ring onto the wheel hub and the outer ring onto the steering knuckle, which requires high equipment and process control requirements.
. Deviation in press fit accuracy may lead to unstable bearing performance, such as excessive clearance or insufficient preload force.Performance Deviation
Due to the difficulty in precise control of installation processes, there is a significant deviation in bearing performance after press fitting, resulting in overall performance lower than subsequent iteration products (such as the second and third generations).
.Limited application scope
Mainly suitable for non drive wheels of front wheel drive vehicles, axle load ≤ 1.2 tons, with a lifespan target of 80000 to 100000 kilometers.
. In driving wheel or high load scenarios, the failure rate significantly increases (such as a 30% higher failure rate of front wheel drive hub bearings in European vans compared to non driving wheels).