Abstract
KEYWORDS:
Ball Screw Drive, Automotive Actuator, Calculation and Testing, X-by-wire, Steering, Brake, Clutch
ABSTRACT:
Ball Screw drives are widely used in different applications in machine tools and industrial applications since many years. They are used to drive several axes in machine tools or to transform a rotational to a lateral motion in lots of industrial applications. The main requirements are stiffness, accuracy and precision. Their importance increased due to the implementation of computer numerical controlled
drives.
In the last years in automotive industries a trend can be seen that hydraulic actuation will be substituted by different electric driven devices. So the hydraulic power steering in the lower car segment is replaced by electromechanical steering, were the steering
motion of the driver is supported by an electric motor. Clutch and shifting automation also uses electric drives to release the clutch or to engage the gears. And finally nearly all suppliers for brakes have electromechanical brakes under development, were the hydraulics will be substituted by electric motors and ball screw drives.
A key element in most of the different so called X-By-Wire-Technologies is the ball screw drive. It shows a comparable power density like hydraulics and a very high efficiency. A maintenance free design and a good cost-benefit-ratio are the main target of the engineering. From the beginning of the development of different X-By-Wire technologies INA is incorporated in those projects with different customers.
The main difference between industrial and automotive applications of ball screw drives is the environment, were lateral forces and deformations can not be prevented. Lots of the experience for industrial ball screw drives can not be used in the field of automotive application of ball screw drives and new tools in terms of calculation, simulation, manufacturing and testing have to be introduced.
These tools are more near described on the basis of practical applications in the field of chassis components, brake and steering.