Sanshin Kogyo Kabushiki Kaisha

Hiroshi Ogino

Yoshikazu Nakayasu

Akihiro Onoue

Takashi Iwashita

A marine propulsion housing arrangement includes an improved construction for inhibiting an influx of water into the housing and for protecting the components thereof. A marine outboard drive comprises a drive unit and at least a swivel bracket that supports the drive unit for pivotal movement with a steering shaft. At least one mount assembly is provided for unifying the drive unit and the steering shaft. The mount assembly includes at least one mount members affixed to the drive unit and a hub member united with the mount member. The hub member is connected to both the drive unit and the steering shaft so as to unify them. A mount cover generally covers both of the mount member and the hub member.

Marine propulsion housing arrangement

An outboard drive is equipped with a water inlet located on a lower casing of the outboard drive. The lower casing includes a nacelle that houses a transmission and a propulsion shaft that are coupled to an engine through a drive train. The propulsion shaft rotates about a longitudinal axis that is aligned with a centerline of the nacelle. The water inlet is located on a front, cone-shaped nose of the nacelle, forward of the transmission and above the longitudinal axis of the of the propulsion shaft. The water inlet communicates with a water passage that guides cooling water to a water pump. The water passage is located in front of the transmission in order to increase the size of the water passage over prior water cooling systems of outboard drives.

Water inlet for marine drive

A transmission arrangement reduces internal stresses and friction within a coupling that links a shift operator with a counter-rotating clutch element of a dual clutch assembly. The shift operator, which interconnects the dual clutches, includes a gap in the connection between the clutches to interject a small degree of play between the clutch elements. The resulting clearance compensates for any adverse tolerance stack-ups which otherwise would produce significant friction between the coupling and the counter-rotating clutch element. The degree of play within the assembly, however, is not so large as to affect the smoothness of the transmission when shifting.

Marine drive transmission

A lower unit for an outboard drive has an elongated length in order to present a streamline shape while providing sufficient width to house a transmission for a counter-rotational propeller system with a forwardly-oriented clutch element. One of the clutch elements of the transmission lies in front of the transmission gears to increase the flow area through an exhaust discharge path behind the transmission. In order to accommodate this transmission structure, the lower unit has an increased with at a point forward of the associated drive shaft. The lower unit also has an increased length as measured from the drive shaft forward in order to present a streamline shape within the water. The elongated length of the lower unit also improves the directional and rolling stability of the outboard drive.

Outboard drive lower unit

An integrated splash and anti-cavitation plate is provided for an outboard motor. The integrated plate decreases the overall weight of the outboard motor in order to improve the motor's performance. The decreased weight also lessens the load on the mounting structure which supports the outboard motor on the watercraft transom. In addition, the distance between the plate and the rotational axis of the propulsion shaft is such that the plate can effectively prevent water splash-up into the mounting structure, even when the outboard motor is run with its propellers partially exposed.

Splash and anti-cavitation plate for marine drive

A transmission for a dual, counter-rotational propeller system incorporates a shift assistor to yieldably cushion transmission engagement. The shift assistor desirably operates between one clutch of a dual clutch assembly and a clutch actuator. The shift assistor specifically yieldably couples the clutch to the actuator. The yieldably coupling permits relative movement between the shift assistor and the clutch during the shifting operation in order to allow the clutches to engage the corresponding gears separately (i.e., at different times). The shift assistor thus reduces coupling shock when shifting the transmission either into a forward or a reverse drive condition.

Shift assistor for marine transmission

An improved water pickup arrangement for a marine propulsion device for picking up cooling water for the propelling, water-cooled internal combustion engine. The lower unit has a bullet-shaped portion and the water inlet openings are formed at the forward and upper ends of this portion.

Cooling water pickup for marine propulsion unit

A transmission for a marine outboard drive includes a compact bearing arrangement to provide an increased flow area for exhaust discharge behind the transmission with a lower unit of the drive. The bearing arrangement also improves the stability of a supported propulsion shaft. The bearing arrangement includes a first bearing assembly which supports the propulsion shaft at a point corresponding with the axial location at which a driving clutch is coupled to the shaft. The clutch selectively engages a driven gear of the transmission to drive the propulsion shaft. A thrust flange on the propulsion shaft desirably is positioned between the first bearing assembly and a second bearing assembly which journals the driven gear.

Bearing arrangement for marine transmission

A bearing carrier and ring nut of a marine outboard drive both attach to a lower unit of the drive by rotating them in the same direction. The bearing carrier includes a threaded front end which screws into a threaded aperture within the lower unit. A ring nut locks the bearing carrier in place by screwing into a hole on the rear face of the lower unit. A locking tab washer desirably locks the ring nut in place. Because the threads on the bearing carrier and the ring nut are of the same hand, the ring nut does not loosen the bearing carrier when threaded into the hole of the lower unit rear face.

Bearing carrier for outboard drive

A transmission system for a counter-rotational propulsion device is easily incorporated into an existing outboard drive of a watercraft to convert the outboard drive from a single propeller drive to a counter-rotational dual propeller system. The transmission system involves a first transmission which selectively couples an inner propulsion shaft with an existing drive shaft of the outboard drive. The inner propulsion shaft in turn drives a rear propeller. A second transmission of the transmission system is provided between the inner propulsion shaft and an outer propulsion shaft. The second transmission reverses the rotational drive direction input by the inner propulsion shaft so as to drive the outer propulsion shaft in an opposite rotational direction. The outer propulsion shaft drives a front propeller which spins in an opposite direction to that of the rear propeller, but asserts a thrust in the same direction as the rear propeller.

Transmission system for counter-rotational propulsion device

A transmission for a counter-rotational propeller system of a watercraft outboard drive includes an improved clutch coupling which allows relative motion between a clutch and a portion of a clutch actuator, while reducing friction and wear between these components. The coupling includes an annular collar that is captured within an inner bore of the clutch. The ends of the collar are journaled within the bore for relative rotation between the collar and the clutch. Sufficient spacing also is maintained between the collar outer periphery and the inner bore wall to prevent contact between the collar and the clutch. A pin connects the collar to the clutch actuator.

Outboard drive transmission system

A lower unit of a marine outboard drive has a unique shape which inhibits boundary layer separation within the water flow stream over the lower unit regardless of the trim position of the lower unit. The lower unit includes a nacelle. The front nose of the nacelle blends smoothly into a supporting strut in a vertical direction to form a generally teardrop-like cross-sectional shape. The front end of the strut fairs the nacelle body from its sharp leading edge to give the lower unit a streamline shape at trim angles approaching a full trim up position of the lower unit. The leading edge of the strut also slopes rearward away from the front nose of the nacelle. The shape of this junction between the upper side of the nacelle and the strut front end gives the front end of the lower unit a generally constant streamline shape as the lower unit rotates through a range of trim angle positions.

Lower-unit for marine outboard drive

A transmission for a counter-rotational propeller system of a watercraft outboard drive provides an increased flow area for exhaust discharge behind the transmission within the lower unit. The transmission includes a pair of counter-rotating gears. A front clutch selectively drives an inner propulsion shaft by engaging the front gear. A rear clutch selectively drive an outer propulsion shaft by engaging either of the gears. The front clutch lies forward of the front gear and the rear clutch is interposed between the gears. The clutching mechanism thus entirely lies forward of the rear gear to provide more space for exhaust discharge flow behind the transmission.

A simple structured propeller shaft assembly for a counter-rotating propeller system of a watercraft outboard drive prevents fishing line, weeds and like debris from entangling on a shaft of the propeller system and damaging the lubricant seals of the shaft assembly. The shaft assembly includes a nut which threads partially onto an end of an outer propeller shaft of the propeller shaft assembly. A thrust washer, carrier by an inner propeller shaft, includes a front hub which partially inserts into the nut adjacent to the end of the outer shaft. The nut, thrust washer and outer shaft end together define a labyrinth path into the space occupied by the lubricant seals between the inner and outer shafts. This labyrinth path inhibits weeds and like debris from wrapping around the inner shaft at a point adjacent to the lubricant seals.

Propeller shaft assembly for marine propulsion system

An improved transmission bearing assembly for a counter-rotating propeller system of a marine outboard drive directly journals the driven gears of the transmission on the propulsion shafts of the outboard drive. The hub of one driven gear is journaled between a portion of an inner propulsion shaft and a hollow end of the outer propulsion shaft. The bearing assembly also supports the hollow end of the outer propulsion shaft at a front end of a bearing carrier and supports a rearward section of the outer shaft at a rear end of the bearing carrier. The span between the bearing assemblies journaling the outer propulsion shaft within the bearing carrier is increased by positioning the bearing assemblies at the ends of the bearing carrier. The positions of the bearing assemblies at the ends of the bearing carrier thus improves the stability of the outer propulsion shaft.

Growing community of inventors

Hamamatsu, Japan

Hiroshi Ogino