*4.3.5 Sealing and lubrication solutions*

Modern automobiles are targeting maintenance-free or maintenance less and fit for life reliable systems. Bearing sealing and lubrication solutions play a vital role in the achieving maintenance and reliability target of the system. Type of sealing (seal material, geometry, type of contacts, etc.) and lubrication selection for the bearing directly affect the bearing performance in operating conditions like temperature, speed, and friction. Good sealing on the bearings also increases bearing resistance to operating condition likes keeping the contaminations out of bearing raceways. Sealed bearings are not only maintenance-friendly but also environmentally friendly too.

**Figure 17** depict the importance of capping (sealing) type in the bearing. Non-contact type of capping is good when bearing need to contain the lubricant like grease into the bearing with fair protection against exclusions, however, contact types of seals gives excellent protection against exclusions as well as retention of lubricants. Low contact capping compromise based on application requirements. However, all these capping is having impact on power loss or additional friction in the system. Non-contact type of capping gives lowest power lost among the all the capping types. Contact type capping is having highest power loss compare to both the non-contact and contact type capping. Typically, low contact type seals are having 30 to 40% higher power lost compare to noncontact type. Contact type capping is having 35 to 45% higher power lost compare to low contact type capping and about 70 to 80% higher power loss compare to non-contact type capping.

**Figure 17.** *Comparison of different type of capping and power loss.*

*Role of Bearings in New Generation Automotive Vehicles: Powertrain DOI: http://dx.doi.org/10.5772/intechopen.94222*

**Figure 18.** *Modern automotive eMotor challenges.*

#### *4.3.6 "Sensorization" solutions*

Modern automotive uses of electronics are increasing for vehicle control as well as operator comfort purposes. Vehicle control systems primarily need feedback from various systems which required sensor. Sensors are typically mounted on or around the critical rotating parts, hence sensors integrated bearings are a natural good choice for reliable signals. It is already proven that in rotating system's generate unique vibration signatures on the support bearing. These unique vibration signals can be processed electronically for multiple vehicle systems health monitoring via sensors. Sensor bearings provides better location as well as the accuracy of the signal for different feedbacks like speed, load, temperatures, etc. for effective vehicle monitoring. The miniaturization of sensor technology is an opportunity for the integration of bearings and sensors for modern automobile sensing needs.

#### *4.3.7 Special electric motor bearings*

Above bearing technology focus areas are covering major areas of eMotor bearings as well. However, some special requirements like current leakage and performance of bearing need special mention in this section (**Figure 18**).

High-frequency current passing through the bearing is detrimental for the bearing performance and there is a high probability of current leakage in eMotor bearings. If the current passed through the bearing generally results in "fluting" or micro pitting on the bearing races and start generating noise. The continued running of the bearing in this condition may encounter catastrophic damage. Bearing with special electric insulation coating, special materials for the rolling element (e.g. Ceramic) are developed and also under development for mass vehicle adoption by lowering cost. In addition to electric current insulations, technology development is also focused on electrical conduction solutions so the leakage current can be bypassed from the rolling area.

#### **5. Conclusion**

Modern Automobiles technology is transforming to enable "connected, autmonomous, shared and electric (CASE). Modern automobile powertrain development is focused on higher efficiency, maintenance free (higher reliability), compactness, light weight and autonomous control using mechatronics capabilities. New generation powertrains utilize lighter materials, lesser number of components and

integrated fuctions to achieve these objectives. Battery electric powertrains, hybrid power trains and hydrogen fueled fuel cell technologies are becoming popular in modern automobiles. Bearings are one of critical component (sub-system) to achieve modern powertrain's demanding technical requirements. It is imperative to bearing engineers to understand critical technical requirements of modern automobiles aggregates functions and bearing performance expection. Understanding aggregate performance and expected bearing technical requirements facilitate optimized solution development. Bearing plays crucial role in enhancing efficiency, integrating the functions, facilitate the compactness to achieve the lightweight powertrain. Bearing technology development focus area concentrating to addressing the modern powertrain's requirements. Bearing technology research and development areas focused on reliability improvement, power dense solutions, integrated functions, friction optimization, sealing/lubrication solutions, adoption of sensors and special application specific eMotors bearings. In addition to primary functions of bearing with the help of modern electronic technologies bearings are performing critical role of overall system health monitoring in the vehicle.

Bearing research is typically aligned to applications requirements and trends of the machine's technology. Modern automobiles are focusing more of passenger comfort with focus on autonomous driving, connected vehicles and electrification of vehicle. These technological requirements pushing bearing research more on sensorization, lower noise, vibration and harshness in addition to reliability improvement, maintenance free operation and application specific solutions. Bearing noise is one of the key concerns in modern powertrain specifically in electric drive trains. Bearing technologist are focusing on this aspect more than ever before. The bearing noise is directly connected to passenger comfort as well as overall system health. Bearing noise is also indication of system health as the issues with any part in the chain directly reflect to bearing vibrations. Leading bearing manufacturers are focusing on the sensor bearing technology as this feedback from vehicle critical parts is key to autonomation of modern automobile vehicles. Chronologically bearing research focus is more on application specific solutions, sensorization, maintenance operations. At system level bearings research is also focused on the "connected vehicle technologies" using on-board diagnostic using vibration signature identification capabilities at the bearing.

However, bearings are having furthermore potential to contribute and enhance role in modern automobiles in future. Future bearing technologies will focus more on the "bearing as a service" than typical product. Bearing as a service includes ability to collect the data, process the data and transfer the data for better understanding of vehicle dynamic behaviors. In modern automobiles bearing role will be second to electronics. The miniaturization of electronics complements to bearings utility exploitations and expansion to bearing space for additional functionalities. In modern automobiles the role bearings are as important and vital as the electronics considering potentials bearings provide for further integration and research.

*Role of Bearings in New Generation Automotive Vehicles: Powertrain DOI: http://dx.doi.org/10.5772/intechopen.94222*
