Functions and Roles

Among the components that comprise an automobile, great importance is placed on steering system performance and reliability. In addition to accurately transmitting the driver’s steering operations to the automobile, the steering system is the man/machine interface delivering information on running conditions from the automobile to the driver.

“Power steering” refers to the components added to assist steering efforts and provide drivers with comfortable maneuverability.

SHOWA’s Approach

In addition to its extensive track record of producing hydraulic power steering systems over the past 20 years, SHOWA also took on the development of electric power steering systems at an early date in response to the heightened need for increased energy conservation.

SHOWA also has launched the first Mass-Production of rack assist type electric power steering system in the world. Given the current trend toward electric controllability aimed at future ITS’s (Intelligent Transport Systems), SHOWA regards this electric power steering system as a fast-growth item, and will strive to fortify the competitiveness of its merchandise with an ample lineup of variations. In hydraulic power steering as well, SHOWA’s newest group of products excels in high performance/ energy conservation results and addresses customers’ diverse needs for advanced EPS and mature HPS.


Gearbox: Part of the rack bar (output shaft) is contained in a hydraulic cylinder through which the system assists in the motion of the rack bar, with the hydraulic pressure generated by a pump driven by engine output.

Energy-saving needs can be met through the use of a variable-capacity pump that varies the delivery flow rate.

A wide variety of products applicable to a broad range of vehicle types, from compact to full- sized cars, are available.


Rack assisted (coaxial type) : RA-EPS

This type has a hollow shaft motor arranged coaxially on the circumference of therack bar in the power-assisting section. This system directly assists the output shaft through a ball screw, it is highly rigid and provides a smooth steering feel designed to deliver a large power output for both mid-sized and full-sized cars.


Pinion assisted : PA-EPS

The power-assisting section of this system is arranged in the pinion-shaft (input-shaft) section. This is a suitable system for compact cars, from small cars using brush motors and those using brushless motors appropriate for high-grade compact cars with high performance / high output. Showa offers a large lineup of product variations.