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.
System Configurations and Images of Vehicle-Mounted State
Types of Power Steering Systems
Power steering is classified into hydraulic power steering (HPS), which uses the engine's power as a drive source, and electric power steering (EPS), utilizing the vehicle's battery. EPS offers of great meritor value energy savings, as it assists only at the time of steering, therefore demand is expected to grow for this type in the near future.
Hydraulic power steering system Pump
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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. |
Electric power steering system
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Rack-assisted (Coaxial type): Can be designed to deliver large output power for mid-sized and full-sized cars. This system directly assists the output shaft through a ball screw. It is highly rigid and provides a smooth steering feel. |
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Pinion-assisted: The power-assisting section is integrated into the steering gearbox, which is installed outside the cabin. This arrangement ensures quieter operation compared with the column-assisted type. This is a suitable system for compact cars. The downsized high-strength reduction gear and small, high-output motor can even meet the need for higher output power. |
