The future evolution of the technology underlying automotive performance

Driving, Steering, and Braking Define How Vehicles Move

I think of my car as “a means to go where I want.” Fundamentally an automobile is designed to turn (steer) freely, stop (brake) whenever you want, and accelerate (drive) you safely to your destination, wherever it is. These functions, driving, steering, and braking, are known as the three major elements of automotive motion.
Driving is an automobile’s most basic function. The power generated by the engine, motor, or other power sources is transmitted to the wheels, moving the car and achieving acceleration along with any other desired movement by the driver.
Steering is a function that transmits the driver’s movement of turning the steering wheel to the wheels to change the direction the vehicle is going. Significant changes in steering systems are expected in the future with the development of autonomous driving.
Braking is a function that applies force to the wheels when the driver steps on the brake pedal to slow the car down and bring it to a stop. To further improve safety, automakers are pursuing electrification of braking systems.
All of these elements are essential for safe and comfortable driving, and require a very high level of reliability for use in automobiles.

◆Technology that Supports Driving

In order to drive at the desired speed, a transmission (gearbox) is needed to regulate power between the engine and the wheels. The transmission optimizes the wheels’ rotation speed and torque (magnitude of load), much like shifting gears on a bicycle. In a conventional, engine-powered vehicle, fuel is burned by the engine to produce energy for driving. It requires greater torque at slower wheel speeds, such as starting to move from a standstill, than when already on the move. Thus, the transmission is responsible for adjusting the relationship between the engine, wheel speed, and torque according to situation. In other words, it shifts gears smoothly and flexibly.

The biggest challenge in driving is reducing energy loss. It takes a lot of energy to run passenger vehicles, which typically weigh over one ton. To reduce CO2 emissions and minimize environmental impact, society demands vehicles that run on less energy. Many technologies have been created for this purpose. For example, automatic transmission (AT) is a mechanism that has evolved remarkably. Automatic transmissions have gained a greater number of speeds, going from three gears about 30 years ago to eight or even ten gears today. This allows the balance between RPM and torque to be finely adjusted, so that the engine's power can be transmitted more efficiently to the wheels, reducing fuel consumption and vehicle wear and tear.

In addition, to reduce energy loss, frictional force must be reduced in the rotating parts of the force-transmitting components. A wide range of the NSK Grou’s products are used in automatic transmissions, including bearings to reduce friction as gears turn and friction material products.Hub unit bearings are used in the wheels to support the weight of the car when driving and the lateral forces applied when turning. They must have durability and reliability in various environments such as rainwater, mud, and snow, and provide smooth rotation.

On the other hand, no matter how efficient the engine is, it consumes more than twice the amount of energy than, theoretically speaking, is needed to drive the car. This is why features have been incorporated to reduce how much the engine runs, including a feature that turns off the engine when idling. The electrification of vehicles is also progressing. For example, there are hybrid vehicles (HEVs) that use both an engine and electric motor, recovering the vehicle’s kinetic energy when decelerating and reusing it as electrical energy, as well as electric vehicles (EVs) that run on motors powered solely by electricity.

One of the challenges in EV driving is the cruising range under battery power. To drive a long distance on a single charge, a large number of batteries must be installed, and space must be secured to carry the batteries. Consequently, there is a need to reduce the size and weight of various components used in automobiles. To get high power from a small motor, it must rotate at high speed. For this, bearings and reduction gears are required that can withstand high speed rotation. Converting battery energy more efficiently and using less energy to drive the car will also increase the cruising range. NSK’s solution to this problem is the Seamless 2-Speed e-Axle Concept (Gen2). Drawing on multiple technologies that NSK has cultivated over the years, this new product is capable of quiet and smooth gear shifting while saving space and supporting higher motor speeds for a comfortable ride.