As a key component of automobiles, the customization of automotive bearings requires comprehensive consideration of various factors such as performance, reliability, cost, and adaptability. The following are the core details and analysis that need to be paid attention to when customizing automotive bearings:
1. Clarify the application scenario and performance requirements
Load type and size
Details: It is necessary to clarify the load type (radial load, axial load or composite load) and peak load value that the bearing can bear. For example, wheel hub bearings need to withstand the vehicle's own weight, braking torque, and lateral forces, while transmission bearings need to adapt to the alternating loads generated by gear meshing.
Impact: Load parameters directly determine the size, material, and internal structural design of bearings (such as raceway curvature and number of rollers).
.Speed and temperature rise
Details: The maximum working speed and continuous operating time of the bearing need to be provided.
. High speed bearings (such as turbocharger bearings) need to consider roller deformation and lubrication failure caused by centrifugal force.Effects: The rotational speed affects the dynamic balance accuracy of the bearing, the design of the cage (such as using nylon or steel cage), and the lubrication method (such as oil mist lubrication or splash lubrication).
.Environmental adaptability
Details: It is necessary to specify the working environment of the bearing (such as high temperature, humidity, corrosive media or dust).
. For example, new energy vehicle motor bearings need to withstand temperature changes of -40 ℃ to 150 ℃ and require anti-corrosion design.Impact: Environmental conditions determine the sealing form of the bearing (such as contact or non-contact sealing), surface treatment (such as galvanizing, Dacromet coating), and material selection (such as ceramic ball or stainless steel cage).
.2. Material and Heat Treatment Process Selection
Bearing Steel Grade
Details: High carbon chromium bearing steel (such as GCr15) is a common choice, but the material needs to be upgraded according to performance requirements.
. For example, long-life bearings can use vacuum degassed steel (such as SUJ2) to reduce inclusions and improve fatigue resistance.Impact: Material purity directly affects the fatigue life and reliability of bearings.
.Heat treatment process
Details: It is necessary to clarify the quenching temperature, tempering temperature, and cooling method.
. For example, wheel hub bearings require martensitic quenching and low-temperature tempering processes to achieve high hardness and wear resistance while retaining toughness.Impact: Improper heat treatment may lead to surface cracks or insufficient hardness in the core of the bearing, shortening its service life.
.Surface strengthening treatment
Details: Choose carburizing quenching, nitriding, or surface coating (such as DLC coating) according to your needs.
. For example, transmission bearing raceways can use carburizing quenching to increase surface hardness, while motor bearings can use ceramic coatings to reduce friction coefficient.Impact: Surface treatment can significantly improve the wear resistance, anti bonding ability, and corrosion resistance of bearings.
.III. Accuracy and Tolerance Control
Dimensional Tolerance
Details: It is necessary to clarify the tolerance levels of the inner diameter, outer diameter, and width (such as P0, P6, P5).
. High precision bearings (such as P5 grade) are required for high-speed or high load scenarios, such as engine tensioner bearings.Impact: Excessive tolerance may lead to vibration, noise, or early failure.
.Rotation accuracy
Details: The allowable values for radial and axial runout of the bearing need to be specified.
. For example, the radial runout of EPS motor bearings needs to be controlled within 1 μ m to ensure that the steering system has no abnormal noise.Impact: Rotation accuracy directly affects the smoothness and lifespan of equipment operation.
.Clearance adjustment
Details: The initial clearance (such as C2, C3, C4) should be selected based on the operating temperature and load.
. Bearings operating in high-temperature environments, such as differential bearings, require a larger clearance to compensate for thermal expansion.Impact: Improper clearance may lead to bearing jamming or premature wear.
.IV. Lubrication and Sealing Design
Lubrication Method Selection
Details: Lubricating grease (such as lithium based grease, polyurea based grease) or lubricating oil should be selected according to the speed and temperature rise.
. For example, high-speed motor bearings require low torque grease, while heavy-duty wheel hub bearings require high drop point grease.Impact: The lubrication method directly affects the friction, wear, and temperature rise of the bearing.
.Sealing structure optimization
Details: The sealing form (such as rubber sealing ring, metal dust cover or combination seal) should be selected according to the environmental conditions.
. For example, agricultural machinery bearings need to use double lip rubber seals to prevent mud and sand from entering.Impact: Seal failure can lead to grease leakage or contamination entering, accelerating bearing failure.
.Lubrication cycle planning
Details: The expected maintenance cycle of the bearing needs to be provided (such as lifelong lubrication or regular grease replenishment).
. For example, the bearings of new energy vehicle drive motors often adopt a lifelong lubrication design and require the use of long-life lubricating grease.Impact: Lubrication cycle affects the maintenance cost and reliability of bearings.
.Fifth, Structure and Installation Adaptability
Bearing Type Matching
Details: The bearing type should be selected based on the load characteristics (such as deep groove ball bearings, tapered roller bearings, or angular contact ball bearings).
. For example, the suspension arm bearings need to use double row tapered roller bearings to withstand composite loads.Impact: Incorrect type selection may lead to premature bearing failure or equipment malfunction.
.Coordination of installation dimensions
Details: The fit tolerance between the bearing and the shaft/seat (such as interference fit or clearance) needs to be provided.
. For example, the fit between the inner ring of the wheel hub bearing and the shaft needs to use interference fit (H7/P6) to prevent loosening.Impact: Improper installation dimensions may cause the bearing to run out of the inner or outer ring, causing vibration and noise.
.Tool and process compatibility
Details: The installation and disassembly methods of bearings need to be considered (such as hydraulic pressing or heating installation).
. For example, large bearings (such as truck wheel hub bearings) need to be installed using a dedicated press to avoid deformation caused by brute force strikes.Impact: Improper installation process may damage bearings or affect their performance.
.Section 6: Testing and Verification
Bench Testing
Details: Life testing, high-speed testing, or environmental resistance testing (such as salt spray testing) are required.
. For example, transmission bearings need to undergo 1 million shift cycle tests to verify durability.Impact: Experiments can expose design flaws and avoid batch quality issues.
.Road test verification
Details: Bearing performance needs to be tested under real or simulated operating conditions.
. For example, new energy vehicle motor bearings need to pass extreme environmental road tests such as high temperature, high altitude, and extreme cold.Impact: Road tests can verify the reliability of bearings in actual use.
.Failure analysis mechanism
Details: It is necessary to establish a bearing failure analysis process and locate the cause of failure through metallographic testing, scanning electron microscopy, and other means.
. For example, if the bearing experiences early peeling, it is necessary to analyze whether it is caused by material defects or insufficient lubrication. Impact: Failure analysis can guide design improvement and enhance product quality. SummaryCustomization of automotive bearings should be based on the core principles of "performance matching, reliability and durability, and controllable cost". Through precise definition of requirements, optimization of material processes, strict control of precision tolerances, reasonable design of lubrication seals, ensuring installation adaptability, and rigorous testing and verification, the ultimate goal is to achieve perfect integration between bearings and the entire vehicle system.
. For customization parties, choosing suppliers with automotive industry experience, technical strength, and quality control systems is crucial, as it can significantly reduce project risks and enhance product competitiveness.