Abstract: To provide a tilt device for a marine propulsion unit comprising a pair of cylinder devices to be disposed at right and left of a marine propelling unit. Also a hydraulic fluid supply/discharge unit which are separately formed from both cylinder devices, respectively and disposed between both cylinder devices to be coupled with the both cylinder devices.

Abstract: To provide a trim-tilt device for a marine propulsion unit in which an armored case of a motor is made of resin and a circulating passage of a hydraulic fluid, which is circulated by a pump, is arranged in the inside of the motor.

Abstract: In a tilt device for a shift propelling machine, a hydraulic fluid supply/discharge device, a pump unit including an integral motor, and a tank is integrally provided in a swivel bracket.

Abstract: A controller for a Hall effect sensor includes a sensor section including a Hall effect sensor with a hysteresis set in the output electric signal characteristic with respect to the magnetic flux density, a power supply section for supplying a source power to the Hall effect sensor, and a signal processor for processing a signal output from the sensor section. The power supply section supplies power with a voltage, which is varied cyclically in a predetermined range and is increased gradually, to the Hall effect sensor.

Abstract: A steering system for a boat propelling apparatus is disclosed, which includes an operation unit, a steering piston-and-cylinder assembly and an operating fluid switching unit. The operation unit causes a steering arm of a propelling unit to be operated with operation of a steering wheel installed in the boat. The steering piston-and-cylinder assembly is connected to an operating fluid supply pump and a drain tank and capable of being supplied with operating fluid. Its piston rod is coupled to the steering arm. The operating fluid switching unit is disposed between the steering piston-and-cylinder assembly on one hand and the operating fluid supply pump and the drain tank on the other hand, and it switches the flow of operating fluid with the operation of the operation unit. It includes a switching section having a poppet valve coupled to the operation unit. The operating fluid switching unit includes a switching section and a normally closed drain control section.

Abstract: A tilt cylinder for tilting an outboard engine has first and second cylinder chambers. A pair of on/off valves is movably disposed in respective fluid passages connected to a hydraulic pump and the first and second cylinder chambers, respectively. The on/off valves are operatively combined with respective shuttle valves which have respective oil passages in facing relationship to the on/off valves, respectively, and respective ball valve bodies for selectively opening the oil passage into communication with each other. When the hydraulic pump is actuated to develop a working oil pressure buildup, one of the on/off valves is opened by the working oil pressure buildup to establish an oil supply passage from the hydraulic pump to one of the first and second chambers, and the other of the on/off valves is opened by the coacting shuttle valve which is moved by the working oil pressure buildup to establish an oil return passage from the other of the first and second chambers to the hydraulic pump.

Abstract: A power steering device for use with a boat propulsion unit has a hydraulic cylinder unit for angularly moving a steering arm of the boat propulsion unit. A rotary valve mechanism for supplying working oil from a working oil tank to the hydraulic cylinder unit and discharging working oil from the hydraulic cylinder unit to the working oil tank comprises a flat valve body having oil holes defined transversely therethrough and a valve housing assembly housing the flat valve body and having ports defined therein for communication with the oil holes, the ports being connected to the working oil tank and the hydraulic cylinder unit. The power steering device also includes a steering shaft for operating the rotary valve mechanism in response to a steering action. The hydraulic cylinder unit, the rotary valve mechanism, and the steering shaft are integrally joined to each other.

Abstract: A tilt cylinder unit for use with an outboard engine on a boat hull has a cylinder, a piston slidably disposed in the cylinder, and a rod having an end coupled to the piston. The cylinder may be coupled to the outboard engine or the boat hull, and the rod may be coupled to the boat hull or the outboard engine. The cylinder has a first chamber which is expanded when the tilt cylinder unit is extended and a second chamber which is compressed when the tilt cylinder unit is contracted, the first and second chambers being defined in the cylinder by the piston. A third chamber, which may be defined in the cylinder or an auxiliary tank separate from the cylinder has a portion filled with a gas. The second and third chambers are interconnected by an orifice, and the first, second, and third chambers are interconnected by a plurality of communication passages. A manually operable valve is coupled between the communication passages for selectively opening and closing the communication passages simultaneously.

Abstract: A power steering device for steering an outboard engine on a small boat has a hydraulic cylinder unit for angularly moving a steering arm of the outboard engine, the hydraulic cylinder unit having a piston rod connected to the steering arm, and a directional control spool valve for supplying a hydraulic pressure to the hydraulic cylinder unit to move the piston rod. A control cable controls the directional control spool valve in response to operation of a steering wheel. The control cable has a core having an end coupled to the piston rod and a sheath covering the core and having an end coupled to the spool of the directional control spool valve. The hydraulic cylinder unit has a cylinder divided by a piston into a first oil chamber through which the piston rod extends and a second oil chamber remote from the piston rod.

Abstract: A power steering apparatus for steering an outboard engine on a boat has a hydraulic cylinder unit for angularly moving a steering arm of the outboard engine, and a hydraulic pump actuatable by a motor for supplying a hydraulic pressure to the hydraulic cylinder unit. The motor is controlled by a motor driver which supplies a first amount of electric energy to the motor when the outboard engine is not steered, and supplies a second amount of electric energy, larger than the first amount of electric energy, to the motor when the outboard engine is steered.

Abstract: The angle of trim of a propulsion unit of a boat is controlled by actuating a tilt and trim unit based on an angle of the propulsion unit. If the angle of the hull of the boat with respect to the horizontal plane or the acceleration of the hull exceeds a predetermined value, the tilt and trim unit is actuated to reduce the angle of trim in overriding relation to a control mode for controlling the angle of trim based on the angle of the propulsion unit.

Abstract: A hydraulic pressure mechanism for angularly lifting and lowering an outboard engine includes a hydraulic cylinder unit comprising a piston assembly and a hollow cylinder, the piston assembly being slidably fitted in the hollow cylinder and dividing a hollow space therein into a first oil chamber and a second oil chamber, a tank for storing working oil, a pump for delivering working oil from the tank to the hydraulic cylinder unit, and a spool valve for supplying working oil from the tank through the pump selectively and exclusively to the first and second oil chambers, thereby to cause the piston assembly and the cylinder to move relatively to each other for enabling the hydraulic cylinder unit to tilt the outboard engine.

Abstract: A connecting structure for a rod in an outboard motor includes a rod having an end forced in a piston, and a stopper ring disposed between the rod and the piston.