Adapter plate, heat shield, and method for thermally isolating a mount coupled to an adapter plate

An outboard motor adapter plate couples a marine engine to a driveshaft housing, and includes an upper rim configured to be coupled to a lower surface of a cylinder block of the engine. A lower rim of the adapter plate is configured to be coupled to an upper surface of a sump located in the driveshaft housing. A wall defines a passageway having an inner perimetral surface, and the inner perimetral surface extends from the upper rim to the lower rim. A mounting area is configured for coupling a mount to the adapter plate. A shield covers at least a portion of the inner perimetral surface adjacent the mounting area, so as to at least partially thermally isolate the mount from heated fluid that drains from the cylinder block, through the passageway, and into the sump. A method and a shield for thermal isolation are also described.

FIELD

The present disclosure relates to outboard motors, and more specifically to an adapter plate that couples a marine engine to a driveshaft housing.

BACKGROUND

U.S. Pat. No. 5,487,687, hereby incorporated herein by reference, discloses an outboard marine drive having a midsection between the upper power head and the lower gear case and having a removable midsection cowl assembly including first and second cowl sections. The midsection housing includes an oil sump in one embodiment and further includes an exhaust passage partially encircled by cooling water and partially encircled by engine oil for muffling engine exhaust noise. The midsection housing also has an oil drain arrangement providing complete and clean oil draining while the outboard drive is mounted on a boat and in the water wherein the operator can change oil without leaving the confines of the boat and entering the water.

U.S. Pat. No. 7,896,304, hereby incorporated herein by reference, discloses a support system for an outboard motor including mounts which are configured and positioned to result in an elastic center point being located closely to a roll axis of the outboard motor which is generally vertical and extends through a center of gravity of the outboard motor. The mounts are positioned so that lines which are perpendicular to their respective center lines intersect at an angle which can be generally equal to 90 degrees. The mounts are positioned in non-interfering relationship with the exhaust components of the outboard motor and its oil sump.

U.S. Pat. No. 8,820,701, hereby incorporated herein by reference, discloses a mounting arrangement for supporting an outboard motor with respect to a marine vessel extending in a fore-aft plane. The mounting arrangement comprises first and second mounts that each have an outer shell, an inner wedge concentrically disposed in the outer shell, and an elastomeric spacer between the outer shell and the inner wedge. Each of the first and second mounts extend along an axial direction, along a vertical direction that is perpendicular to the axial direction, and along a horizontal direction that is perpendicular to the axial direction and perpendicular to the vertical direction. The inner wedges of the first and second mounts both have a non-circular shape when viewed in a cross-section taken perpendicular to the axial direction. The non-circular shape comprises a first outer surface that extends transversely at an angle to the horizontal and vertical directions. The non-circular shape comprises a second outer surface that extends transversely at a different, second angle to the horizontal and vertical directions. A method is for making the mounting arrangement.

Unpublished U.S. patent application Ser. No. 14/591,493, filed Jan. 7, 2015, hereby incorporated herein by reference, discloses a midsection housing for an outboard motor that includes a driveshaft housing having an oil sump provided therein. An adapter plate is coupled to a top of the driveshaft housing. The adapter plate has an inner surface along which oil from an engine mounted on the adapter plate drains into the oil sump. First and second pockets are formed in an outer surface of the adapter plate on first and second generally opposite sides thereof, the first and second pockets configured to receive first and second mounts therein. A water jacket is formed between the inner and outer surfaces of the adapter plate. The water jacket extends at least partway between the inner surface of the adapter plate and each of the first and second pockets, respectively. A method for cooling a mount is also provided.

SUMMARY

In one example of the present disclosure, an outboard motor adapter plate for coupling a marine engine to a driveshaft housing includes an upper rim configured to be coupled to a lower surface of a cylinder block of the engine. A lower rim of the adapter plate is configured to be coupled to an upper surface of a sump located in the driveshaft housing. A wall defines a passageway having an inner perimetral surface, and the inner perimetral surface extends from the upper rim to the lower rim. A mounting area is configured for coupling a mount to the adapter plate. A shield covers at least a portion of the inner perimetral surface adjacent the mounting area, so as to at least partially thermally isolate the mount from heated fluid that drains from the cylinder block, through the passageway, and into the sump.

According to another example of the present disclosure, a method is for at least partially thermally isolating a mount coupled to an outboard motor adapter plate from heated fluid that drains from a marine engine cylinder block coupled to an upper rim of the adapter plate, through a passageway in the adapter plate, and into a sump coupled to a lower rim of the adapter plate. The method comprises locating a mounting area configured for coupling the mount to the adapter plate, and providing a shield that is configured to cover at least a portion of an inner perimetral surface of the passageway adjacent the mounting area so as to prevent the heated fluid from running over the inner perimetral surface adjacent the mounting area.

Another example of the present disclosure is of a shield for at least partially thermally isolating a mount coupled to an outboard motor adapter plate from heated oil that drains from a marine engine cylinder block coupled to an upper rim of the adapter plate, through a passageway in the adapter plate, and into an oil sump coupled to a lower rim of the adapter plate. The shield is configured to cover at least a portion of an inner perimetral surface of the passageway adjacent a mounting area configured for coupling the mount to the adapter plate.

DETAILED DESCRIPTION

In the present 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 only and are intended to be broadly construed.

FIG. 1illustrates an outboard motor adapter plate10for coupling a marine engine, shown schematically at12, to a driveshaft housing14. As conventional, an upper end of a driveshaft15is coupled to a crankshaft (not shown) of the marine engine12. The driveshaft15extends through the adapter plate10into the driveshaft housing14, and thereafter couples at its lower end to a propeller shaft via a beveled gearset, all as is known in the art. A sump is shown schematically at16, and is held beneath the adapter plate10so as to collect fluid that drains from the marine engine12. This fluid, for example oil, has been provided to the marine engine12by an oil pump and is used to lubricate the moving parts of the engine12and to keep them cool while the engine is running. In other examples, the fluid provided to lubricate and/or cool the engine12may be automatic transmission fluid, water, or power steering fluid, depending on the engine and its internal parts. In this respect, the mention of the fluid as being “oil” throughout the specification, and reference to element16as being an “oil sump” is not meant to be limiting on the scope of the present claims.

Referring toFIG. 2, the adapter plate10comprises an upper rim18configured to be coupled to a lower surface of a cylinder block19(shown schematically inFIG. 1) of the engine12. This coupling can be accomplished by inserting a plurality of fasteners (not shown) through a plurality of holes21spaced around the rim18, and into correspondingly spaced holes in the bottom of the cylinder block19. A gasket may be provided between the upper rim18and the lower surface of the cylinder block19. The adapter plate10also has a lower rim20configured to be coupled to an upper surface22of the oil sump16located in the driveshaft housing14. Again, this may be done by inserting fasteners into holes23spaced around the upper surface22of the oil sump16, and into correspondingly spaced holes in the lower rim20. A gasket may also be provided between the lower rim20and the upper surface22of the oil sump16. The adapter plate10also has a wall24defining a passageway26having an inner perimeteral surface28. In the example shown, the inner perimeteral surface28extends from the upper rim18of the adapter plate10to the lower rim20of the adapter plate10. The inner perimeteral surface28may extend around the entire inner perimeter of the wall24, although only the foremost part of the inner perimeteral surface28is shown herein. Together, the coupling between the cylinder block19and upper rim18, the inner perimetral surface28extending from the upper rim18to the lower rim20, and the coupling between the lower rim20and the upper surface22of the oil sump16provide a fluid-tight pathway for drainage of oil from the engine12, through the adapter plate10, and into the oil sump16. In any of theFIGS. 1-7, the adapter plate, oil sump, and driveshaft housing could instead be formed as one part, for example by using techniques such as lost foam molding or laser sintering. In this case, the lower “rim”20of the adapter plate10would be integral with the upper surface22of the oil sump16.

Referring now toFIGS. 1 and 3, the adapter plate10further comprises a mounting area30that is configured for coupling a mount, such as mounts32a,32bto the adapter plate10. In the example shown, depressions38a,38bare formed in an outer surface of the adapter plate10. The depressions38a,38bare concave areas in the outer surface of the adapter plate10that at least partly define the mounting area30. The mounts32a,32bare coupled to the adapter plate10adjacent the depressions38a,38b, which brings them in close proximity to the outer surface of the adapter plate10. The mounts32a,32bare held to the adapter plate10by covers34a,34b. Fasteners (not shown) extend through holes36in each of the covers34a,34bto attach the mounts32a,32bto the adapter plate10. As is known, a connector may extend through a hole40a,40bin each of the mounts32a,32b, respectively, and into an attachment bracket, which is coupled to a transom bracket, which is in turn coupled to a transom of a marine vessel. An example of this type of coupling to a marine vessel is shown in U.S. Pat. No. 8,820,701, which was incorporated by reference herein above, and will therefore not be described further herein. In one example, the mounts32a,32bmay comprise an outer metallic shell surrounding an inner metallic shell and having an elastomeric spacer (or spacer made of other dampening material) between the inner and outer shells. One example of this type of mount is also described in the '701 patent. It should be understood, however, that the mounts32a,32bcould take different forms and/or include parts other than shown herein or in the '701 patent.

Through research and development, the present inventors have realized that high mount temperatures contribute to thermal fatigue of the mount elastomer or dampening material, which degrades the engine mounts' performance over time. In prior art adapter plates, hot oil drains from the engine cylinder block19to the oil sump16directly over the inner perimetral surface28of the adapter plate10. Because these prior art adapter plates are in direct or nearly direct thermal contact with the mounts32a,32b, the mounts become very hot. Current methods of cooling mounts bring water to or near the mounts; however, in some cases the addition of cooling passages that are either cast in or created by additional hoses are costly and not package friendly. With increasing space constraints required by today's consumers, outboard motor designers are increasingly asked to build a high-powered motor with a compact design. In an attempt to make outboard motors more compact, the mounts are moved closer to the adapter plate, for example by being placed in depressions38a,38bas shown inFIG. 3, or by being placed in pockets such as shown in the '701 patent. Consequently, the mounts are then closer to the hot, oil-wetted surfaces inside the adapter plate, where they encounter the higher temperatures that degrade their performance.

Through research and development, the present inventors have realized that oil or other fluid at a temperature of 260-300° F. in close proximity to the mounts32a,32bfar exceeds temperatures that can be tolerated by the elastomeric spacer provided in the mount. The outer metallic shell of the mounts32a,32band the aluminum of the adapter plate10do little to insulate the elastomeric spacer in the mount from heat. One example of an elastomer that can be used in the mounts is natural rubber, for which a temperature of 158° F. is preferred. If the rubber becomes marginally hotter than 150° F. it will volcanize or harden, and will therefore not be able to damp the vibrations of the outboard motor as well. These vibrations will therefore be transferred to the transom bracket and to the marine vessel. If the rubber becomes too hot, it will melt and will therefore not function at all. Additionally, when the rubber becomes too hot, its fatigue life can be decreased, and in some cases even halved. This means that over repeated use, mounts32a,32bthat encounter hot temperatures will need to be replaced more often than mounts that are kept at lesser temperatures. Using an elastomer that is able to encounter and withstand higher temperatures is a possibility; however, high temperature elastomers sometimes have poor isolation and fatigue properties when compared to natural rubber. It should be understood that although natural rubber is one elastomer that can be used in the mounts32a,32bof the present disclosure, any other elastomer or dampening material could potentially be used in the mounts32a,32b, and the type of elastomer or dampening material used is not limiting on the scope of the present disclosure.

The inventors of the present disclosure have therefore invented a shield42(seeFIGS. 2 and 4) that covers at least a portion of the inner perimeteral surface28adjacent the mounting area30, so as to at least partially thermally isolate (and in some examples fully thermally isolate) the mounts32a,32bfrom heated oil or other fluid that drains from the cylinder block19, through the passageway26, and into the oil sump16. The fact that the shield42covers at least a portion of the inner perimeteral surface28that is adjacent the mounting area30is illustrated by a dashed line showing of the mounts32a,32binFIG. 4. It should be understood that the mounts32a,32bare actually not visible from the inner perspective view of the adapter plate10shown inFIG. 4; rather, the mounts32a,32bare located on the opposite (outer) side of the adapter plate10, as shown inFIG. 3. However, the dashed line location of the mounts32a,32bis provided in order to show how the shield42is proximate the mounts in the mounting area30.

As shown herein, the shield42is located radially inwardly of the inner perimeteral surface28. This means that the heated oil from the cylinder block19drains over the shield42, instead of directly over the inner perimetral surface28of the adapter plate10. The shield42therefore prevents or limits the hot oil from contacting the inner perimeteral surface28of the wall24of the adapter plate10, and therefore fully or partially thermally isolates the mounts32a,32bfrom the hot oil. In the example shown, the shape of the shield42generally mimics the shape of the inner perimeteral surface28of the passageway26. For example, the shield42as depicted inFIG. 2has two wings44a,44band a central area46that connects the two wings44a,44b. The central area46has a semi-cylindrical opening48at its upper end, which partly surrounds a driveshaft passageway50in the adapter plate10. The wings44a,44bextend from either side of the central area46at an angle from one another so as to follow the angled shape of the inner perimetral surface28. The shield42is shown as one part, but could alternatively be several parts connected together in a fluid-tight manner.

In one example, there is an air gap43(FIG. 4) left between the inner perimeteral surface28and the foremost face of the shield42that faces the foremost portion of the inner perimetral surface28. In other words, although the shape of the shield42generally mimics the shape of the inner perimeteral surface28, it need not match it exactly, and can be offset from the inner perimetral surface28to allow for some air to pass between the two. This allows for cooling in this area, and also prevents transfer of heat from the shield42to the adapter plate10. In another example, no air gap43is provided between the inner perimetral surface28and the shield42. For example, the inner perimetral surface28could be dipped, coated, overmolded, or in other ways covered in an insulating material, which insulating material would constitute the shield42, proximate the mounting area30. Alternatively, the shield42could be separately molded to exactly fit against the geometry of the inner perimetral surface28.

The shield42has a first edge52that is attached to the wall24of the adapter plate10proximate the upper rim18. In one example, a liquid-tight seal54is provided between the first edge52and the upper rim18and/or the inner perimetral surface28proximate the upper rim18. The liquid-tight seal54may be integrally formed with the first edge52of the shield42. Alternatively, the seal54may comprise a strip of material that extends along the first edge52and that is applied after the shield42is formed. The seal54may also be applied as an epoxy or glue after the shield42has been placed appropriately in the adapter plate10. The seal54can extend down the wings44a,44bof the shield42as well, although such extension is not shown herein, in order to illustrate the air gap43. There is less likelihood that oil will come between the shield42and the inner perimeteral surface28of the adapter plate10in the area of the wings44a,44bthan in the area of the first edge52, where oil drains by gravity onto the shield42from the cylinder block19. The seal54may also be located along the bottom edge53of the shield42, although such seal is not shown herein, as there is also less likelihood that oil will come between the shield42and the inner perimetral surface28in this area as well.

The shield42can be made of many different types of materials. In one example, the shield42is made of metal and the air gap43between the shield and the inner perimeteral surface28provides the insulation between the heated oil running over the shield42and the mounts32a,32bin the mounting area30. In another example, the shield42is made of a piece of wood with an epoxy coating or casing. In another example, the shield42is made of a polymer-based plastic, such as polyamide (nylon). Nylon provides good structural properties to the shield42and is also a good insulator that does not allow transfer of heat from the shield42to the adapter plate10. Using a shield42allows the mounts32a,32bto be made with natural rubber instead of synthetic rubber, although as mentioned above, synthetic rubber could still be used, because the shield42acts as an oil deflector that creates a thermal barrier between the heated oil and the mounts32a,32b. The barrier slows and reduces the transfer of heat from the oil to the adapter plate10and/or oil sump16by preventing direct thermal contact between the hot engine oil and the adapter plate and/or oil sump. By diverting the oil, less heat is absorbed by the adapter plate and/or oil sump, which reduces the heat that is applied to the metal and elastomer of the mount, without the addition of passages or hoses for cooling water. The shield42is easily molded to different contours, which allows it to package easily in most engines without major modifications.

Just as the material of the shield42can vary, the material of the seal54between the shield42and the inner perimetral surface28and/or upper rim18can also vary. As mentioned above, the seal54could be a silicone strip. The seal54could alternatively be a piece of pliable rubber. An epoxy or glue could also serve as a seal that is applied after the shield42is put in place in the adapter plate10. Any material that is at least initially flexible, compliable, or elastomeric would work as the seal54. In one example, the seal54is made of a thermoplastic vulcanizate (TPV) in the thermoplastic elastomer (TPE) family, known as Santoprene™ and provided by ExxonMobil Chemical Company of Houston, Tex.

In the embodiment shown herein, the bottom edge53of the shield42extends approximately to the lower rim20of the adapter plate10. In alternative embodiments, the bottom edge53of the shield42extends partway into the oil sump16, to insulate the oil sump16from heat at its upper end. In the embodiment shown herein, the central area46and the wings44a,44bof the shield42extend over the foremost half of the inner perimetral surface28. In other embodiments, the shield42extends around the entire inner perimetral surface28of the adapter plate10, instead of being located only in an area proximate the mounting area30.

Now turning toFIGS. 5-7, a second embodiment of an adapter plate and associated shield will be described. The adapter plate110shown in these figures has an upper rim118for coupling to a cylinder block19of an engine12, for example via fasteners inserted in holes121. The adapter plate110also has a lower rim120for coupling to a driveshaft housing14. Although the cylinder block19and driveshaft housing14are not shown inFIGS. 5-7, it should be understood that these parts are relatively similarly configured to those shown inFIG. 1. In the example ofFIGS. 5-7, however, the driveshaft housing may have an integral oil sump, and oil from the cylinder block may drain through the adapter plate110and into the integral oil sump in the driveshaft housing. The adapter plate may also be integral with the oil sump and driveshaft housing, as mentioned herein above. Additionally, the driveshaft may not extend through the entirety of the driveshaft housing, in some examples.

The adapter plate110has a wall124including a passageway126having an inner perimeteral surface128. A mounting area130is configured for coupling a mount132(or two mounts) to the adapter plate110. The adapter plate110also has a shield142, but in this instance the shield142comprises a first portion142aand a second portion142bthat envelop the mounting area130therebetween. Seals154a,154bare provided between the first portion142aand second portion142bof the shield. In the example shown herein, the first and second portions142a,142bof the shield142are shown as an upper and a lower half. Alternatively, the first and second portions142a,142bcould be provided as first and second lateral halves (i.e. a port portion and a starboard portion), or a lower main body and an upper lid (or vice versa). In still other examples, the shield142is made of one single part or more than two parts.

In this example, the first and second portions of the shield142a,142benvelop the mounting area130, which comprises an alcove166in the outer surface of the adapter plate110. The seal154aseals a first edge152aof the first portion of the shield142ato the upper rim118, or at least to a portion thereof. This first edge152ais somewhat triangular, and is located at an aft end of the first portion142aof the shield and the adapter plate110. Toward the fore end of the first portion142aof the shield, the first portion142aof the shield forms a rectangular edge156a. A downwardly extending skirt or wall158aextends from the rectangular edge156a. The wall158ahas a rectangular cutout160aat the foremost portion of the first portion142aof the shield. The second portion142bof the shield has similar edges152band156b, as well as similar wall158band cutout160b. Together, the walls158a,158band cutouts160a,160bseal around an outer surface of a casting162having a driveshaft passageway150extending therethrough at it foremost end. This casting162extends in the aft direction across the passageway126such that it forms the alcove166for the mounting area. Effectively, the casting162splits the passageway126in half, such that oil from the engine cylinder block19flows down on either side of the first portion142aof the shield and of the casting162. The first and second portions of the shield142a,142bcan be attached to upper and lower halves168a,168bof the casting162by fasteners (not shown) that extend through a plurality of holes170in the upper and lower halves168a,168bof the casting162. Alternatively, the shield portions142a,142bcan be held in place via a tight fit with the seals154a,154b, or by a glue or epoxy-type seal. Air gaps143a,143b(FIG. 6) can be left between the first and second portions142a,142bof the shield and the upper and lower halves168a,168bof the casting162. These air gaps143a,143bprovide added thermal insulation between the oil-heated surface of the shield142and the mount132.

In an alternative embodiment, only the first portion142aof the shield is provided. This provides a thermal barrier between the mount132and oil that drains on top of the first portion142aof the shield from the engine cylinder block19. The second portion142bof the shield can alternatively be provided to block the mount132from radiant heat that rises from the hot oil in the oil sump.

The materials of the shield142and seal154a,154bmay be the same as those mentioned above with respect to the first embodiment.

The present disclosure therefore is of a shield42,142for at least partially thermally isolating a mount32,132coupled to an outboard motor adapter plate10,110from heated fluid that drains from a marine engine cylinder block19coupled to an upper rim18,118of the adapter plate10,110through a passageway26,126in the adapter plate, and into a sump16coupled to a lower rim20,120of the adapter plate10,110. The shield42,142is configured to cover at least a portion of an inner perimeteral surface28,128of the passageway26,126adjacent a mounting area30,130configured for coupling the mount32,132to the adapter plate10,110. In one example, the shield42,142is shaped such that its shape generally mimics the shape of the inner perimeteral surface28,128of the passageway26,126.

Turning now toFIG. 8, a method for at least partially thermally isolating a mount32,132coupled to an outboard motor adapter plate10,110from heated fluid that drains from a marine engine cylinder block19coupled to an upper rim18,118of the adapter plate through a passageway26,126in the adapter plate, and into a sump16coupled to a lower rim20,120of the adapter plate will be described. The method comprises, with reference to box801, locating a mounting area30,130configured for coupling the mount32,132to the adapter plate10,110. As shown in box803, the method comprises providing a shield42,142a,142bthat is configured to cover at least a portion of an inner perimetral surface28,128of the passageway adjacent the mounting area30,130so as to prevent the heated fluid from running over the inner perimeteral surface adjacent the mounting area.

The method may further comprise placing the shield42,142radially inwardly of the inner perimetral surface28,128. The method may further comprise forming the shield42,142such that its shape generally mimics the shape of the inner perimeteral surface of the passageway. An air gap43,143a,143bmay be provided between the inner perimetral surface28,128and the shield. The shield may be formed of polyamide plastic. A liquid-tight seal54,154a,154bbetween an edge52,152a,152bof the shield and upper rim18,118of the adapter plate may be provided. The liquid-tight seal may be formed integrally with the edge of the shield. The shield may alternatively be formed as a first portion142aand a second portion142bthat are configured to envelop the mounting area130therebetween.