1. Field of the Invention
The present invention relates to a hydraulic pressure generating device for generating a hydraulic pressure to be supplied to a hydraulic cylinder unit that is actuatable in response to turning of a steering wheel for angularly moving a steering arm to steer an outboard engine mounted on the back of a small boat.
2. Description of the Prior Art
Some known power steering apparatus for outboard engines on boats have a hydraulic pressure generating device which utilizes the power of the outboard engine for rotating a hydraulic pump such as a vane pump, a gear pump, or a trochoid pump to supply working oil to a hydraulic cylinder unit for angularly moving a steering arm.
Since the conventional hydraulic pressure generating device relies upon the engine power at all times, even when the power steering apparatus are not in operation, the engine power is consumed in rotating the hydraulic pump and hence suffers an energy loss. It is possible to actuate the hydraulic pump with an electric motor and to energize the electric motor only when the power steering apparatus operates to steer the boat. However. because the electric motor starts to operate with a delay when the power steering apparatus is brought into operation, the hydraulic pump cannot quickly supply a hydraulic pressure to the power steering apparatus, which is therefore poor in response.