Automotive:Power Steering Systems

Functions and Roles

"Turning" is a basic function of the vehicle born by steering sysytem which changes the direction of the vehicle by turning tires through steering wheel operation. Power steering is a device providing comfortable operation to the driver though steering wheel operation assistance (lighter feel).

Types of Power Steering Systems

Hydraulic power steering(HPS

Hydraulic power steering(HPS)

This is a system designed to assist the operation of the rack bar by generating oil pressure in the pump with the engine's output. Energy savings achieved by utilizing the variable capacity pump. Showa offers a large lineup of product variations applicable to cars ranging from Mini cars to large large-sized (luxuary) cars.

Electronic power steering(EPS) More Details

Rack assisted (coaxial type): RA-EPS

Rack assisted (coaxial type) : RA-EPS

This type has a hollow shaft motor arranged coaxially on the circumference of the rack 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

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.

Power assist unit

Power assist unit

This is an general-purpose power assist unit that applies PA-EPS technology into another Showa product.
This unit is applicable for providing steering power assistance in ATVs and other small vehicles.

SHOWA'S Approach

The history of the SHOWA power steering business covers more than 30 years, since the manufacture of gear pumps back in 1977. Due to our early preoccupation with the needs of society for energy saving devices, Showa took the initiative in 1977 offering rack assist (coaxial type) RA-EPS power steering system for passenger cars to the market. With regard to hydraulic power steering (HPS) systems, SHOWA offered its variable capacity hydraulic pumps on the market at the same time, as a response to customer needs for energy saving devices. Later on, the pinion assist PA-EPS power steering system was included in this lineup, and since than, the scale of our power steering business has grown to approximately 4,000,000 cars annually. Currently, as our response to the rapid changes in market trends towards electrically powered steering systems and the growing diversity of our customers’ needs, SHOWA is enhancing the competiveness of its substantial product lineup and making progress in the field of control technology while focusing on product improvement, and our product development efforts continue to advance.