Information
-
Patent Grant
-
6192853
-
Patent Number
6,192,853
-
Date Filed
Tuesday, May 25, 199925 years ago
-
Date Issued
Tuesday, February 27, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Argenbright; Tony M.
- Benton; Jason
Agents
- Knobbe, Martens, Olson & Bear LLP
-
CPC
-
US Classifications
Field of Search
US
- 123 196 W
- 123 196 R
- 123 195 P
- 440 88
-
International Classifications
-
Abstract
An outboard motor oil pump driving arrangement wherein the oil pump is driven by a spline connection positioned between the engine crankshaft and the driveshaft. There is a spline connection also between the crankshaft and the driveshaft and this spline connection is spaced axially from the spline connection to the pump drive element with the splines being space from each other by a non-splined section so as to reduce stress risers and to make assembly and disassembly easy even if the parts are deformed.
Description
BACKGROUND OF THE INVENTION
This invention relates to an oil pump for a four cycle outboard motor and more particularly to an improved driving arrangement for such an oil pump.
Although two cycle internal combustion engines have been the accepted powerplant for use in outboard motors for a long time, environmental conditions are dictating the use of four cycle engines. This presents some significant problems to the designer because of the more complicated nature of a four cycle engine when compared to a two cycle engine. One of the particular complicating factors with applying four cycle engines to outboard motors is the lubrication system for such engines.
Although the use of recirculating of lubrication systems provide much better environmental control than is possible with two cycle engines, there are significant problems with adapting conventional automotive type lubricating systems to outboard motor applications. One reason for this is the fact that the outboard motor crankshaft or engine output shaft rotates about a vertical rather than a horizontal axis. Thus, the crankcase chamber is not practical to be utilized as an oil reservoir for the engine.
Therefore, it has been the practice to provide an oil reservoir for the engine in the area below the engine and generally in the otherwise void area formed at the upper end of the driveshaft housing. This means, however, that the oil must be pumped from this reservoir to the engine lubricating system by an oil pump. The drive and location of these pumps is quite important. That is, the pump should be located in a manner that is driven easily off the engine and yet so that it is positioned in proximity to the oil pan or oil reservoir so as to minimize the length of flow paths, particularly on the inlet side of the pump.
Although one form of arrangement for driving the oil pump for a four cycle engine in an outboard motor has employed driving of the oil pump off of an overhead cam shaft of the engine, there are some potential disadvantages with this type of arrangement. Specifically, the cam shafts are driven at one-half crankshaft speed and hence, the oil pump will be driven slower than the crankshaft. This may not always provide the requisite amounts of lubricant for some types of engines.
There has been proposed, therefore, an arrangement for driving the oil pump from the engine output shaft at the interface where it joins the driveshaft for the propulsion unit. Several embodiments of such arrangements are shown in the copending application entitled “Oil Pump for Outboard Motor”, Ser. No. 08/996,529 filed Dec. 23, 1997 in the name of Hitoshi Watanabe et al., which application is assigned to the assignee hereof.
With the arrangement shown in this copending patent application, the oil pump is driven off of the engine crankshaft at the area where it is joined to the driveshaft. This permits the oil pump to be positioned in close proximity to the underlying oil pan and greatly simplifies the construction. In addition, the oil inlet and outlet passages can be positioned free of the driving and driven components and thus permit a more leak-free environment.
One embodiment of that application utilizes the splined connection between the driveshaft and the engine output shaft as the driving arrangement for the oil pump. Although this has significant advantages, the construction shown in that application may present some problems in certain types of operations.
This may be understood best by reference to
FIGS. 1-3
of this application which illustrate generally the arrangement shown in the embodiment of FIG. 16 of that application. This construction will now be described by reference to these figures which are basically cross-sectional views taken through the area at the upper portion of the driveshaft housing and the lower unit and the lower portion of the power head. As described below,
FIG. 1
is a cross-sectional view taken through the oil pump in this area while
FIG. 2
is an enlarged view of the area shown in FIG.
1
and
FIG. 3
is a further enlarged view of the area encompassed by the circle
3
in FIG.
2
.
As seen in these figures, the engine crankshaft
21
has a portion that protrudes below a lower face of the engine cylinder block, crankcase assembly
22
. This portion of the crankshaft
21
is provided with a splined opening
23
. A splined end
24
of a driveshaft
25
is received in and thus drivingly coupled to the engine crankshaft
21
. The driveshaft
25
depends into the driveshaft housing and lower unit of the outboard motor for driving its propulsion device.
It should be seen that the splined portion
24
of the driveshaft
25
is substantially longer than the length of the crankshaft splines
23
. This permits driving engagement with a pump driving element
26
of a gerotor type oil pump, indicated generally by the reference numeral
27
and mounted on top of a supporting plate
28
formed at the upper end of the driveshaft housing. This pump driving member
26
has a splined inner portion
29
so as to provide a driving relationship therewith. The outer portion of the driving member
26
drives the inner gear
31
of the gerotor type pump
27
which cooperates with a fixed outer gear
32
to provide the pumping action in a manner well known in the art.
As may be best seen in
FIGS. 2 and 3
, the arrangement is such that there must be a small clearance area z between the lower end of the crankshaft
21
and the upper end of the inner portion of the pump driving member
31
. Thus, the splined portion
24
of the driveshaft
25
has a first part
33
which is engaged with the crankshaft splines
23
and a second part
34
that is engaged with the inner splines of the pump drive member
31
these being the splines
29
. The driveshaft
24
is obviously subjected to varying and at times substantial torsional forces. This means that there will be stress raised areas WI and W
2
at the ends of the splined connections between the crankshaft
21
and the pump driving member
31
. Thus, there is a risk that a fracture or failure may occur in this area. Of course, this can be offset by making the diameters larger and the pieces larger, but this is obviously not desirable.
In addition to this problem, even if failure does not occur, a permanent deformation of the splines in the area z and specifically the splined portion
24
of the driveshaft
25
may become deformed and it may be difficult to disassemble the construction.
It is, therefore, a principal object of this invention to provide an improved oil pump drive arrangement suitable for use in an outboard motor.
It is a further object of this invention to provide an improved and simplified oil pump drive arrangement for an outboard motor of the type generally described and one in which stress risers and other problems associated therewith can be eliminated.
SUMMARY OF THE INVENTION
This invention is adapted to be embodied in an outboard motor oil pump and drive arrangement for a lubricating system of the engine that propels the water propulsion device of the outboard motor. The outboard motor has a powerhead that is comprised of a powering four cycle internal combustion engine and a surrounding protective cowling. A driveshaft housing and lower unit depends from the powerhead and contains the water propulsion device. The engine is positioned in the powerhead so that a crankshaft of the engine rotates about a vertically disposed axis. A driveshaft depends into the driveshaft housing and lower unit for driving the water propulsion device. The engine lubricating system includes an oil pan that is positioned below the engine. The oil pump is positioned below the engine and above the oil pan. The oil pump has a drive element for driving the oil pump. A first spline connection is formed between the crankshaft and the driveshaft for driving the driveshaft from the crankshaft. A second spline connection is provided between the crankshaft and the drive element for driving the oil pump from the crankshaft. The first and second spline connections comprise a pair of axially spaced apart splines formed on one of the crankshaft and the driveshaft and separated by a smaller diameter non-splined portion thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
(Prior Art) is an enlarged cross-sectional view taken through the connection between an engine crankshaft and a driveshaft of a prior art type of outboard motor construction and shows a driving connection therebetween an oil pump.
FIG. 2
(Prior Art) is an enlarged cross-sectional view showing the spline connections.
FIG. 3
(Prior Art) is an enlarged cross-sectional view of the area encircled in FIG.
2
.
FIG. 4
is a side elevational view of an outboard motor constructed in accordance with an embodiment of the invention, shown attached to the transom of an associated watercraft which is shown partially in cross-section and in phantom.
FIG. 5
is an enlarged, side elevational view of the powerhead of the outboard motor with a protective cowling broken away and portion of the engine and of the upper portion of driveshaft housing broken away and shown in section.
FIG. 6
is an enlarged, front elevational view of the component shown in
FIG. 5
showing the protective cowling again in cross-section and a portion of the lower part of the engine and the upper portion of the driveshaft housing in cross-section.
FIG. 7
is a top plan view of the powerhead of the outboard motor showing the surrounding protective cowling in phantom and the engine in cross-section.
FIG. 8
is a partially schematic view of the lubricating system for the engine, with a portion broken away and shown in section.
FIG. 9
is a top view of the exhaust guide and oil pump showing the lubricant flow paths.
FIG. 10
is a cross-sectional view, in part similar to
FIG. 1
but shows the corresponding connection between the crankshaft oil pump and driveshaft in accordance with the invention.
FIG. 11
is an exploded view of the assembly shown in FIG.
10
and specifically the splined connections thereof.
FIG. 12
is an enlarged cross-sectional view of the splined connection shown in
FIG. 10
but illustrating in more detail the geometric relationship of the splined portions.
FIG. 13
is a partially assembled view showing how the guide plate and oil pump are inserted onto the driveshaft housing.
FIG. 14
is an exploded view showing the components of
FIG. 13
assembled and the engine in place for assembly upon the guide plate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
Referring now in detail to the drawings and initially to
FIG. 1
, an outboard motor embodying the invention is identified generally by the reference numeral
51
and is shown as attached to the transom
52
of a watercraft hull. The hull is shown partially in cross-section and in phantom and is identified by the reference numeral
53
.
The outboard motor
51
is comprised of a powerhead, indicated generally by the reference numeral
54
that is comprised of a powering internal combustion engine, indicated generally by the reference numeral
55
and surrounded by a protective cowling. This cowling includes a lower cowling member
56
and an upper cowling member
57
that is detachably connected to the lower cowling member
56
in a suitable manner.
A skirt portion
60
is provided below the lower cowling member
56
and encircles the upper portion of a driveshaft housing lower unit assembly, indicated generally by the reference numeral
58
. This unit
58
includes a driveshaft housing portion
59
to which a lower unit housing portion
61
is affixed.
The engine
55
is supported upon a support or guide plate
62
that is mounted at the upper side of the driveshaft housing portion
59
and which extends partially upwardly into the lower portion of the lower cowling member
56
.
A clamping, swivel bracket assembly, indicated generally by the reference numeral
63
, is provided between the driveshaft housing portion
56
and the transom
52
of the watercraft
53
. This assembly
63
includes a steering assembly for steering of the outboard motor
51
about a vertically extending axis and tilt and trim arrangement for trimming of the outboard motor about a horizontally extending axis. These mechanisms are well known in the art, and for that reason, further description of them is not believed to be necessary to permit those skilled in the art to practice the invention.
The construction of the engine
55
will be described in more detail shortly be reference to the remaining figures. However, it is mounted in the powerhead
54
upon the guide plate
62
so that its crankshaft, indicated at
64
, rotates about a vertically extending axis. This is done so as to facilitate connection, in a manner which will be described in more detail later, to an oil pump
65
for driving the oil pump and to a driveshaft
66
.
The driveshaft
66
depends into the driveshaft housing and lower unit assembly
58
and terminates in the lower unit outer housing
61
. There it drives a propeller shaft
67
through a conventional bevel gear type reversing transmission
68
for driving a propulsion device for the watercraft such a propeller
69
.
The construction of the engine
55
will now be described referring in primary detail to
FIGS. 5-7
. The engine
55
is, in the illustrated embodiment, of the four cylinder, inline type and operates on a four stroke principal. Although the invention is described in conjunction with an engine having such a number of cylinders and such a configuration, it will be readily apparent to those skilled in the art how the invention can be practiced with engines having other cylinder numbers and other cylinder placement.
The engine
55
is comprised of a cylinder block
71
that forms four horizontally extending, vertically spaced, cylinder bores
72
. Piston
73
reciprocate in the cylinder bores and are connected by connecting rods
74
to the throws of the crankshaft
64
. The crankshaft
64
is journal for rotation within a crankcase chamber that is formed by a crankcase member
75
and the skirt
76
of the cylinder block
71
to which it is affixed.
A cylinder head assembly, indicated generally by the reference numeral
77
, is affixed to the end of the cylinder block
71
opposite that closed by the crankcase member
75
. The cylinder head assembly
77
may be of any known type and is depicted as being of the twin overhead cam shaft type.
This is comprised of an intake cam shaft
78
and an exhaust cam shaft
79
that are journaled within a cam shaft cavity formed by the cylinder head
77
and a cam shaft cover
81
that is affixed thereto. The cam shafts
78
and
79
are journaled in the cylinder head assembly by means that include bearing caps
82
.
A timing drive comprised of a driving sprocket
83
, which is affixed to the crankshaft
64
and specifically the upper end thereof, is provided for driving the cam shafts
78
and
79
in timed relationship to the crankshaft
64
at one-half its rotational speed. The sprocket
83
drives a drive belt or chain
84
which, in turn, cooperates with sprockets
85
fixed to the upper ends of the intake and exhaust cam shafts
78
and
79
in a known manner. A timing cover
86
encloses this timing drive mechanism as well as a flywheel magneto
87
that is driven off of the upper end of the crankshaft
64
.
An induction and charge forming system supplies an air and fuel charge to the combustion chambers formed by the cylinder head assembly
77
, pistons
73
and cylinder bores
72
. The induction system is comprised of a plenum chamber or a surge tank
88
that is positioned adjacent the crankcase member
75
and which has a plurality of runner sections
89
that extend to throttle bodies
91
. The throttle bodies
91
have throttle valves which are not shown but which are controlled in a suitable manner for controlling the speed of the engine
55
.
The throttle bodies
91
cooperate with intake passages
92
formed in the cylinder head assembly so as to deliver the charge to the combustion chambers of the engine. The flow of the charge into the combustion chambers is controlled by intake valves
93
that are operated by the lobes of the intake cam shaft
78
in a known manner.
The air for the induction system is supplied to the interior of the protective cowling through an inlet opening formed in the outer cowling by a cover member
94
that defines an intake chamber that communicates with the interior of the cowling through a tuned inlet opening
95
.
Fuel is supplied to the inducted air by a suitable charge forming system. This may comprise either a carburetor or carburetors or fuel injectors which can inject either directly into the combustion chambers or into the intake passages of the induction system. This fuel is supplied by means of a fuel pump
96
that is driven off of lobes of the intake cam shaft
74
by means of a rocker arm assembly
97
.
The admitted charge is ignited by spark plugs
98
that are mounted in the cylinder head assembly
77
and which are fired by a suitable ignition system.
The ignited charge bums and expands to drive the engine
55
. The burnt charge then is exhausted through exhaust passages
99
formed in the cylinder head assembly
77
on the side opposite the intake passages
92
. These exhaust passages
99
are valved by exhaust valves
101
that are controlled by the exhaust cam shaft
79
in a known manner.
The cylinder head exhaust passages
99
communicate with an exhaust manifold
102
that is formed integrally within the cylinder block
71
. The exhaust manifold
102
extends downwardly and communicates with an exhaust passage
103
formed in the guide plate
62
.
An exhaust pipe
104
is affixed to the underside of the guide plate
62
and cooperates with an expansion chamber formed by an inner shell
105
of the driveshaft housing
59
. This inner shell has a discharge opening
106
that communicates with a suitable exhaust system for discharging the exhaust gases to the atmosphere.
The engine
55
is provided with a lubricating system which, as has been noted, includes the oil pump
65
. This lubricating system will be described by reference to
FIG. 8
in addition to
FIGS. 5-7
.
The lubricating system includes a lubricant or oil tank
106
that is mounted on the underside of the guide plate
102
and which has a central opening defined by inner wall
107
which surrounds the exhaust pipe
104
and forms an upper extension of the expansion chamber defined by the shell
105
. This oil tank
106
has a suitable external drain
108
by which the oil may be discharged to the outside of the outboard motor
51
for servicing purposes.
A pickup tube
109
depends into the oil tank
106
and cooperates with a fitting
111
which, in turn, communicates with a supply passage
112
formed in the guide plate
62
and which extends upwardly to an opening in an outer member
113
of the housing of the oil pump
65
. The oil pump
65
is of the gerotor type and its components will be described later primarily by reference to
FIGS. 10-14
.
The oil that is pressurized by the pump
65
is delivered to a delivery passage
114
which is also formed in the guide plate
62
. This passage
114
communicates with vertically extending main oil passage
115
that extends upwardly through the crankcase member
75
and which flows into the inlet fitting of a detachable oil filter
116
that is mounted on the crankcase member
75
in an easily accessed position at one side thereof.
Oil that has passed through the filter
116
flows through a supply passage
117
to a main oil gallery
118
that is formed in the crankcase member
75
. This main oil gallery
118
has branch passages
119
which extend to the main bearings
121
for the crankshaft
64
. These main bearings
121
are formed by the cylinder block and by the crankcase member
75
.
In addition, other oil galleries (not shown) supply oil to the cam mechanism and cam shafts as well as any other components of the engine that are to be pressure lubricated. The oil is then drained and returned through return passages back to the oil pan
106
in any suitable manner. This includes a return passage
122
and drain line
123
that are formed in the pump housing
113
.
The construction of the oil pump
65
will now be described in detail by particular reference to
FIGS. 10-14
with the pump assembly shown best in
FIG. 10
being described first. As has been noted, the pump assembly
65
is mounted on the guide plate
62
and includes an outer housing
113
. This outer housing
113
defines a pumping cavity
124
in which an outer, fixed gear
125
and a rotatable inner driven gear
126
are positioned.
As noted, the pump is of the gerotor type and the pumping action between the inner and outer gears
126
and
125
draws fluid into the pumping chamber
124
and discharges it through the pressure outlet already described. A cover plate
127
is affixed to and closes the upper side of the pump cavity
124
.
The driveshaft
66
extends upwardly through an oil seal
128
mounted on the underside of the pump housing
113
. The upper end of the driveshaft
66
extends into a cavity formed in the nose of the crankshaft
64
.
The crankshaft
64
is provided with an internal female splined portion
129
that has a length L which is equal to or slightly greater than the length
1
of a spline portion
131
formed at the upper end of the driveshaft
66
. The internal splines
129
of the crankshaft
64
terminates slightly above their lower face. Hence, the splines
131
and
129
are in continuous engagement and there are no splines that extend through unsplined portions so as to cause stress risers.
A pump driving element
132
is mounted so that it extends partially above the pump cover
127
and slightly below the lower face of the pump housing
113
. This pump drive member
132
has a driving portion
133
on its outer surface that is engaged with a corresponding driving portion on the inner gear
126
to provide a driving relationship with the inner, pumping gear
126
of the pump
65
.
This pump drive member
132
also has a cylindrical portion
134
which is partially coextensive with the driving portion
133
and in which female splines
135
are formed at a length A. An unsplined portion
136
extends upwardly of this portion and partially around the lower end of the crankshaft
64
as clearly seen in
FIGS. 10 and 12
.
A groove
137
is formed on the lower portion of the drive member
132
at the lower terminus of the portion
134
. An o-ring seal
138
is received therein for sealing engagement with an unsplined portion of the driveshaft
66
.
Spaced from the spline portion
131
of the driveshaft
66
is a second spline portion
139
which is spaced from the spline portion
131
by a reduced diameter cylindrical portion
141
. The splines
139
have a length a which is equal to or slightly less than the length a of the splines
135
of the pump drive member
132
. Again, therefore, the splines
139
and
135
will be in substantially full engagement therewith with each other and there will be thus no stress risers formed.
The area below the splines
139
is provided with a reduced diameter portion
142
so as to again avoid stress raisers.
Thus, the assembly can be easily put together and removed in the manner that will become apparent by reference to
FIGS. 13 and 14
. First, once the driveshaft
64
is in position, the guide plate
62
with the assembled pump
65
on it is slid into place by moving it in a downward direction.
After this, the engine
55
can then be installed on top of this as seen in
FIG. 14
so that the spline connections are completed. Thus, the assembly is very easy to assemble and disassemble. Furthermore, even if there are large deflections in the shafts due to torsional loadings, the splines
131
and
129
and
139
and
135
will always be in full engagement and will not be deformed. Thus, even if there is a permanent deformation in the driveshaft the pump mechanism can be easily disassembled for servicing.
Thus, it should be readily apparent that the objects of the invention are well met and a robust simple and very compact pump drive assembly is provided in accordance with the invention.
Of course, the foregoing description is that of a preferred embodiment of the invention and various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.
Claims
- 1. An outboard motor oil pump and drive arrangement for a lubricating system of the engine that propels the water propulsion device of said outboard motor, said outboard motor having a powerhead comprised of a powering four cycle internal combustion engine and a surrounding protective cowling, and a driveshaft housing and lower unit depending from said powerhead and containing said water propulsion device, said engine being positioned in said powerhead so that a crankshaft of said engine rotates about a vertically disposed axis, a driveshaft depending into said driveshaft housing and lower unit for driving said water propulsion device, said engine lubricating system includes an oil pan that is positioned below said engine, said oil pump being positioned below said engine and above said oil pan, said oil pump having a drive element for driving said oil pump, a first spline connection formed between said crankshaft and said driveshaft for driving said driveshaft from said crankshaft, and a second spline connection between said crankshaft and said drive element for driving said oil pump from said crankshaft, said first and said second spline connections comprise a pair of axially spaced apart spline sets formed on one of said crankshaft and said driveshaft and separated by a non-splined portion thereof.
- 2. An outboard motor as set forth in claim 1, wherein the first spline connection for driving the driveshaft is formed by inter-engaging splines on the driveshaft and on the crankshaft.
- 3. An outboard motor as set forth in claim 1, wherein the second spline connection for driving the pump drive element is formed by inter-engaging splines on the driveshaft and on the pump drive element.
- 4. An outboard motor as set forth in claim 3, wherein the first spline connection for driving the driveshaft is formed by inter-engaging splines on the driveshaft and on the crankshaft.
- 5. An outboard motor as set forth in claim 1, wherein the non-splined portion separating the spline sets has a smaller diameter than the spline sets.
- 6. An outboard motor as set forth in claim 5, wherein the diameter of the non-splined portion separating the spline sets is not greater than the root diameter of the spline sets.
- 7. An outboard motor as set forth in claim 1, wherein the length of the male member of at least one of the spline connect is not greater than the female member of said one spline connections.
- 8. An outboard motor as set forth in claim 7, wherein the length of the male member of both of the spline connections is not greater than the female member of the respective spline connection.
- 9. An outboard motor as set forth in claim 1, wherein the driveshaft is the common member that forms the axially spaced splines sets of the first and second spline connections.
- 10. An outboard motor as set forth in claim 9, wherein the first spline connection for driving the driveshaft is formed by inter-engaging splines on the driveshaft and on the crankshaft.
- 11. An outboard motor as set forth in claim 9, wherein the second spline connection for driving the pump drive element is formed by inter-engaging splines on the driveshaft and on the pump drive element.
- 12. An outboard motor as set forth in claim 10, wherein the first spline connection for driving the driveshaft is formed by inter-engaging splines on the driveshaft and on the crankshaft.
- 13. An outboard motor as set forth in claim 12, wherein the non-splined portion separating the spline sets has a smaller diameter than the spline sets.
- 14. An outboard motor as set forth in claim 13, wherein the diameter of the non-splined portion separating the spline sets is not greater than the root diameter of the spline sets.
- 15. An outboard motor as set forth in claim 14, wherein the length of the male member of at least one of the spline connections is not greater than the female member of said one spline connections.
- 16. An outboard motor as set forth in claim 15, wherein the length of the male member of both of the spline connections is not greater than the female member of the respective spline connection.
- 17. An outboard motor as set forth in claim 16, further including a non-splined portion formed on driveshaft below its lowermost spline set that has a smaller diameter than said lowermost spline set and the portion of said driveshaft below said non-splined portion.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-145767 |
May 1998 |
JP |
|
US Referenced Citations (12)