Yamaha Hatsudoki Kabushiki Kaisha

Mitsuhiro Ryuman

Takayoshi Suzuki

Daisuke Nakamura

Hirotaka Kaji

A boat propulsion unit includes a power source, a propeller, a shift position switching mechanism, a control device, and a retention switch. The propeller is driven by the power source to generate propulsive force. The shift position switching mechanism has an input shaft connected to a side of the power source, an output shaft connected to a side of the propeller, and clutches that change a connection state between the input shaft and the output shaft. A shift position of the shift position switching mechanism is switched among forward, neutral, and reverse by engaging and disengaging the clutches. The control device adjusts an engagement force of the clutches. The retention switch is connected to the control device. When the retention switch is turned on by an operator, the control device controls the engagement force of the clutches to retain a hull in a predefined position. The boat propulsion unit provides a boat propulsion unit that can accurately retain a boat at a fixed point.

Boat propulsion unit

A boat propulsion unit includes a power source, a propeller, a shift position changing mechanism, a control device, and a speed reducing switch. The shift position changing mechanism has an input shaft, an output shaft, and first and second clutches. The first and second clutches change the connection state between the input shaft and the output shaft. In the shift position changing mechanism, the first and second clutches are engaged or disengaged, thereby changing the shift position among forward, neutral, and reverse. The control device controls connecting forces of the first and second clutches so that the propeller generates propulsive forces in the direction opposite to the present propulsive direction of a hull when the speed reducing switch is turned on by the operator of the boat. The boat propulsion unit easily retains the propulsive speed of a hull substantially at zero.

A marine propulsion system that achieves both an acceleration performance and top speed closer to the performance desired by a boat driver includes an engine, propellers rotated by the driving force of the engine, a transmission mechanism arranged to convey the driving force of the engine to the propellers at least after shifting into a low speed reduction gear ratio and into a high speed reduction gear ratio, an acceleration sensor arranged to detect the acceleration of a hull propelled by the rotation of the propellers, and a control section and an ECU arranged to carry out the control for changing the reduction gear ratio of the transmission mechanism. The control section and the ECU are configured to control the transmission mechanism to shift from the low speed reduction gear ratio into the high speed reduction gear ratio based on the acceleration of the hull.

Marine propulsion system

A boat propulsion system includes a control section, a thrust calculation section, a thrust generating unit, a thrust detection section, and a control section. An operating amount is input to the control lever by operation of an operator. An accelerator detector detects the input operating amount of the control lever. The thrust calculation section calculates a thrust intended to be generated from the operating amount of the control lever to output a calculated thrust. The thrust generating unit generates a thrust. The thrust detection section detects a thrust actually generated on the thrust generating unit to output it as an actual thrust. The control section controls an output of the thrust generating unit so that the actual thrust approaches the calculated thrust.

Growing community of inventors

Shizuoka, Japan

Mitsuhiro Ryuman