FIELD

The present disclosure generally relates to systems and methods for suspending a lubricant in a marine propulsion device, and more particularly to systems and methods for suspending a lubricant in a marine propulsion device to minimize windage loss.

BACKGROUND

The following U.S. Patents and Patent Applications provide background information and are incorporated by reference in entirety.

U.S. patent application Ser. No. 16/171,490 discloses an outboard motor that has a powerhead that causes rotation of a driveshaft, a steering housing located below the powerhead, wherein the driveshaft extends from the powerhead into the steering housing; and a lower gearcase located below the steering housing and supporting a propeller shaft that is coupled to the driveshaft so that rotation of the driveshaft causes rotation of the propeller shaft. The lower gearcase is steerable about a steering axis with respect to the steering housing and powerhead.

U.S. Pat. No. 5,009,621 discloses counterrotating propeller drive mechanism for a marine propulsion system incorporates a torque splitting device which consists of a differential gear means and a ratio gear means. The torque splitting device assigns a selectable fixed fraction of the engine torque to each propeller regardless of power, thrust, and speed conditions. The rear one of the two propellers adjusts its rotational speed relative to the front propeller in response to changes in the front propeller's wake and in this way maintains optimum propulsive efficiency over a wide range of operating conditions. Furthermore, precise matching of front and rear propeller parameters for a given application is no longer required.

U.S. Pat. No. 5,791,950 discloses an improved twin propeller marine propulsion unit. A vertical drive shaft is journaled in the lower gearcase and drives a pair of bevel gears. A pair of concentric propeller shafts are mounted in the lower torpedo section of the gearcase and each shaft carries a propeller. A slidable clutch is movable between a neutral, a forward, and a reverse position and serves to operably connect the outer propeller shaft with one of the bevel gears when the clutch is moved to the forward drive position. A gear is mounted for sliding movement in unison with the clutch and acts to operably engage the inner propeller shaft with the second bevel gear when the clutch is in the forward drive position so that both propellers are driven in opposite directions to provide forward motion for the watercraft. The propulsion unit also includes a dual cooling water pick-up system in which seawater is drawn to the water pump both through a series of vertical inlet ports in the gearcase and through a plurality of inlet holes that are located in the forward end of the lower torpedo section. Exhaust gas from the engine is discharged through the rear end of the lower housing section through axial passages in the hub of the forward propeller and then across the outer surface of the rear propeller.

SUMMARY

This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

One embodiment of the present disclosure generally relates to a system for suspending a lubricant in a marine propulsion device having a gearcase, the gearcase defining a gearset cavity for containing a propeller shaft gearset rotated by a driveshaft. The system includes a pump device configured to pump the lubricant away from the gearset cavity, and a reservoir located away from the gearset cavity and configured to receive the lubricant from the pump device. An input passage conveys the lubricant from the pump device to the reservoir, and an output passage conveys the lubricant from the reservoir to the gearset cavity. The reservoir is configured to retain at least 15% of the lubricant circulating between the gearset cavity and the reservoir.

Another embodiment generally relates to a system for suspending a lubricant in a marine propulsion device having a gearcase, the gearcase defining a gearset cavity for containing a propeller shaft gearset rotated by a driveshaft. The system include an oil scraper positioned in the gearset cavity such that the lubricant disposed on the propeller shaft gearset is diverted therefrom, and a reservoir located above the gearset cavity and configured to contain the lubricant diverted from the propeller shaft gearcase therein. An input passage conveys the lubricant diverted by the oil scraper to the reservoir, and an output passage conveys the lubricant from the reservoir to the gearset cavity. Rotation of the propeller shaft gearset generates a pressure that forces the lubricant into the reservoir via the input passage.

Another embodiment generally relates to a method for suspending a lubricant in a marine propulsion device having a gearcase, the gearcase defining a gearset cavity for containing a propeller shaft gearset rotated by a driveshaft. The method includes pumping the lubricant away from the gearset cavity with a pumping device, and positioning a reservoir above the gearset cavity, where the reservoir is configured to contain the lubricant pumped by the pumping device. The method includes fluidly connecting an input passage for conveying the lubricant from the pumping device to the reservoir, and fluidly connecting an output passage for the lubricant to drain from the reservoir into the gearset cavity. The reservoir is configured to retain at least 15% of the lubricant circulating between the gearset cavity and the reservoir.

Various other features, objects and advantages of the disclosure will be made apparent from the following description taken together with the drawings.

