The present disclosure generally relates to outboard marine engines and more particularly to bedplate and cover assemblies for vertical shaft outboard marine engines having at least one cooling water jacket and at least one oil drain-back area located adjacent to bearings for a crankshaft.
U.S. Pat. No. 7,198,019 is incorporated herein by reference and discloses a lubricating system for a marine engine. The lubricating system provides a lubrication deflector which extends from the cylinder block of the engine toward rotating surfaces of a crankshaft and/or connecting rod. A lubrication drainage passage is provided as an integral part of a cylinder block of the marine engine to direct a flow of liquid lubricant away from the lubrication deflectors and downwardly toward a lubrication reservoir, or sump. The passage is located away from the rotating crankshaft and reciprocating connecting rods.
This Summary is provided to introduce a selection of concepts that are further described hereinbelow 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 scope of the claimed subject matter.
In certain examples, an outboard marine engine comprises: an engine block; a crankcase on the engine block; a crankshaft disposed in the crankcase for rotation about a crankshaft axis; a cover on the crankcase; a bedplate disposed between the engine block and the cover, the bedplate having a plurality of bearings for supporting rotation of the crankshaft; and a cooling water jacket that extends parallel to the crankshaft axis along a radially outer portion of the plurality of bearings. The cooling water jacket carries cooling water for cooling the plurality of bearings. At least one oil drain-back area is located adjacent to the cooling water jacket. The at least one oil drain-back area drains oil from the crankcase.
In certain examples an outboard marine engine comprises a cover that extends along a row of piston-cylinders on an engine block. The cover at least partially defines a cooling water jacket and also has an inner surface that defines at least one oil drain-back area for receiving and draining oil that is radially thrown from a crankshaft during operation of the outboard marine engine.
In certain examples, an outboard marine engine comprises a crankshaft, an engine block that has a row of radially extending piston-cylinders, a bedplate having a radially inner side that is fastened to the engine block; and a cover having a radially inner surface that is fastened to a radially outer surface of the bedplate. The cover and the bedplate at least partially define a cooling water jacket that carries cooling water for cooling bearings of a crankshaft. The bedplate and the radially inner side of the cover together define at least one oil drain-back area for receiving and draining oil that is radially thrown from a crankshaft during rotation.
Examples of apparatuses for outboard marine engines are described with reference to the following drawing figures. The same numbers are used throughout the drawing figures to reference like features and components.
In the present description, certain terms have been used for brevity, clearness and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatuses described herein may be used alone or in combination with other apparatuses. Various equivalents, alternatives and modifications are possible within the scope of the appended claims. Each limitation in the appended claims is intended to invoke interpretation under 35 U.S.C. §112(f), only if the terms “means for” or “step for” are explicitly recited in the respective limitation.
During research and experimentation with lubricating systems and cooling systems for marine engines, the present inventors have identified two problems. The first is that relatively high oil temperature in the engine environment can cause the oil to quickly degrade and can also increase the temperature of seals and other components within the engine. The high temperatures require more robust seals and components, thus adding cost. The second problem identified by the inventors is that windage friction in the crankcase of the engine causes a loss of power. Windage friction is affected by the amount of oil that flows through the main bearings and subsequently into the crankcase and the rotating and reciprocating cranktrain.
The present disclosure provides increased oil drain-back areas and increased water cooling areas, as compared to prior art arrangements. The inventors have found that more effectively cooling the main bearing bulkheads in the crankcase reduces thermal expansion of the bulkheads, which in turn reduces the running clearances of the main bearings. This results in less oil flow, which leads to cooler oil and less power lost to friction. The present disclosure incorporates the noted oil drain-back areas, which allow for shorter bulkheads and thus lighter weight. Those having ordinary skill in the art would recognize the cost and performance advantages that follow from the above mentioned features.
As shown in
As shown in
In this example, the cooling water jacket 30 is partially defined by the bedplate 26 and partially defined by the cover 24. More specifically, the outwardly directed cooling water jacket surface 44 is provided by the bedplate 26 and the inwardly directed cooling water jacket surface 46 is provided by the cover 24. A cooling water inlet 56 is located at a lower end of the cooling water jacket 30. A cooling water outlet 58 is located at an upper end of the cooling water jacket 30. Cooling water flows vertically upwardly through the cooling water jacket 30 from the cooling water inlet 56 to the cooling water outlet 58, as shown at arrows 68.
As shown at arrows 70 in
In use, as shown by arrows 68 in
The outboard marine engine 10 has been found by the present inventors to provide improved water cooling of all of the plurality of main bearings, thus reducing temperature and related thermal expansion of the bearings. Less clearance between the bearings and journals of the crankshaft can be provided, which results in less oil flow. Reducing oil flow reduces friction, which in turn reduces oil temperature. The need for cast iron caps to reduce flow can be avoided due to the decreased bearing temperature, which allows for less cost and weight. In some examples, the apparatus can be made of die cast aluminum, thereby reducing cost.
The present disclosure thus provides different examples of an outboard marine engine 10, 110, 210 having an engine block 12, 112, 212; a crankcase 22, 122, 222 on the engine block; a crankshaft 18, 118, 218 disposed in the crankcase for rotation about a crankshaft axis 20, 120, 220; a cover 24, 124, 224 on the crankcase; a bedplate 26, 126, 226 disposed between the engine block and the cover, the bedplate having a plurality of bearings 28, 128, 228 for supporting rotation of the crankshaft; and a cooling water jacket 30, 130, 230 that extends parallel to the crankshaft axis along radially outer portions 32, 132, 232 of the bearings. The cooling water jacket carries cooling water at 68, 168 and optionally 276, 278 for cooling the bearings 28, 128, 228. Oil drain-back areas 34, 36; 134, 136; 234, 236 are located adjacent to the cooling water jacket and drain oil from the crankcase. The cooling water jacket is located adjacent to each bearing in the plurality of bearings and in certain examples is located between the first and second oil drain-back areas.
In certain examples, the bedplate 26, 126, 226 has a radially inner side 84, 184, 284 that is fastened to the engine block 12, 112, 212. The cover has a radially inner surface 86, 186 that is fastened to a radially outer surface 88, 188 of the bedplate. In certain embodiments, a cooling plate 272 is disposed between a radially inner surface 286 of the cover and a radially outer surface 288 of the bedplate. In certain examples the cover and the bedplate at least partially define the cooling water jacket that carries cooling water for cooling bearings of the crankshaft. In certain examples, the bedplate and the radially inner side of the cover together define at least one oil drain-back area for receiving and draining oil that is radially thrown from the crankshaft during rotation.
In the foregoing description, certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different configurations, systems, and method steps described herein may be used alone or in combination with other configurations, systems and method steps. It is to be expected that various equivalents, alternatives and modifications are possible within the scope of the appended claims. Each limitation in the appended claims is intended to invoke interpretation under 35 U.S.C. §112(f) only if the terms “means for” or “step for” are explicitly recited in the respective limitation.
The present utility patent application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/787,699, filed Mar. 15, 2013, which is incorporated herein by reference.
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Number | Date | Country | |
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61787699 | Mar 2013 | US |