Development of Single Cylinder Power Trim and Tilt Device For Outboard Motors

Larger outboard motors are usually equipped with “power trim and tilt” mechanism (referred to as “FIT”). The mechanism plays an important role to attain good performance and proper function of the craft. (See Fig. 1)

Basically, PTT has not been evolved out of its original configuration for 15 years or so. It consists of three hydraulic cylinders positioned in parallel; one of them is used for tilting, and other two for trimming. In recent years, however, the outboard motor market had a strong demand for PTT on mid and small size outboard motors. Such, demand necessitated a new type of PTT that is more compact and less expensive than conventional PTT, and still retains equivalent function and performance.

This paper describes first-in-industry coaxial double cylinder PTT (referred to as SPTT; abbreviation of Single-cylinder Power Trim and Tilt), especially focusing on its unique design and layout. SPTT was developed to meet the strong demand in the market, and currently applied in our mid-size outboard motors.

Fig. 1