U.S. patent application number 10/227506 was filed with the patent office on 2004-10-14 for lubricant pump seal for outboard motor.
Invention is credited to Takahashi, Masanori.
Application Number | 20040203300 10/227506 |
Document ID | / |
Family ID | 19080478 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040203300 |
Kind Code |
A1 |
Takahashi, Masanori |
October 14, 2004 |
LUBRICANT PUMP SEAL FOR OUTBOARD MOTOR
Abstract
A lubricant pump seal for an outboard motor is provided. The
lubricant pump seal comprises a first sealing body in an upper
clearance formed between an upper through hole of a lubricant pump
casing and a driveshaft extending through the upper through hole, a
second sealing body in a lower clearance formed between a lower
through hole of the lubricant pump casing and the driveshaft
extending through the lower through hole, a third sealing body in
the lower clearance below the second sealing body, and a fourth
sealing body in the lower clearance between the second and third
sealing bodies. Preferably, the lubricant pump seal further
comprises a fluid communication passage between a space in the
lower clearance and a lubricant reservoir or interior space of a
cowling. When negative pressure is generated in the space during
operation of the lubricant pump, fluid flows through the passage
and into the space, thereby eliminating the negative pressure and
preventing moisture from penetrating the space.
Inventors: |
Takahashi, Masanori;
(Hamamatsu, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
19080478 |
Appl. No.: |
10/227506 |
Filed: |
August 22, 2002 |
Current U.S.
Class: |
440/88P ;
440/88L |
Current CPC
Class: |
F01M 1/02 20130101; F01M
2001/0292 20130101; B63H 20/002 20130101 |
Class at
Publication: |
440/088.00P ;
440/088.00L |
International
Class: |
B63H 021/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2001 |
JP |
2001-251912 |
Claims
1. A lubricant pump seal for an outboard motor, the outboard motor
comprising an internal combustion engine, a water propulsion
device, a drive shaft configured to transmit torque from the engine
to the water propulsion device, a lubricant pump configured to
supply lubricant to the internal combustion engine, the lubricant
pump including a pump casing enclosing a pump chamber, the drive
shaft extending through the pump casing, a rotor housed in the pump
chamber for rotation with the drive shaft, a first sealing body for
sealing an upper clearance formed between an upper part of the pump
casing and the drive shaft, a first passage configured to guide
liquid lubricant to the pump chamber and a second passage
configured to guide air to an outlet of the second passage, the
outlet being disposed at a point outside the pump chamber and
within the pump casing where negative pressure is generated during
operation of the pump, the first sealing body being disposed
between the pump chamber and the point.
2. A lubricant pump seal for an outboard motor, the outboard motor
comprising an internal combustion engine, a water propulsion
device, a drive shaft configured to transmit torque from the engine
to the water propulsion device, a lubricant pump configured to
supply lubricant to the internal combustion engine, the lubricant
pump including a pump casing enclosing a pump chamber, the drive
shaft extending through the pump casing, a rotor housed in the pump
chamber for rotation with the drive shaft, a first sealing body for
sealing an upper clearance formed between an upper part of the pump
casing and the drive shaft, and second and third sealing bodies for
sealing a lower clearance formed between a lower part of the pump
casing and the drive shaft, a fourth sealing body is disposed
between the second and third sealing bodies in an axial direction
of the drive shaft, the fourth sealing body sealing the lower
clearance, further comprising a lubricant reservoir and a fluid
communication passage between a space in the lower clearance
sandwiched between the second and third sealing bodies and the
lubricant reservoir.
3. The lubricant pump seal of claim 2, wherein the pump casing
comprises a casing body enclosing the pump chamber and supporting
the first and second sealing bodies, and a separate casing member
secured to a lower surface of the casing body and supporting the
third and fourth sealing bodies, an upper surface of the casing
member including a groove, wherein at least a portion of the
passage comprises the groove.
4. The lubricant pump seal of claim 2, wherein the pump casing
comprises a casing body enclosing the pump chamber and supporting
the first and second sealing bodies, and a separate casing member
secured to a lower surface of the casing body and supporting the
third and fourth sealing bodies, a lower surface of the casing body
including a groove, wherein at least a portion of the passage
comprises the groove.
5. The lubricant pump seal of claim 2, wherein the lubricant
reservoir comprises a crank chamber of the engine.
6. The lubricant pump seal of claim 2, wherein the lubricant
reservoir is located below a crank chamber of the engine.
7. A lubricant pump seal for an outboard motor, the outboard motor
comprising an internal combustion engine, a water propulsion
device, a drive shaft configured to transmit torque from the engine
to the water propulsion device, a lubricant pump configured to
supply lubricant to the internal combustion engine, the lubricant
pump including a pump casing enclosing a pump chamber, the drive
shaft extending through the pump casing, a rotor housed in the pump
chamber for rotation with the drive shaft, a first sealing body for
sealing an upper clearance formed between an upper part of the pump
casing and the drive shaft, and second and third sealing bodies for
sealing a lower clearance formed between a lower part of the pump
casing and the drive shaft, a fourth sealing body is disposed
between the second and third sealing bodies in an axial direction
of the drive shaft, the fourth sealing body sealing the lower
clearance, further comprising a cowling enclosing the engine and a
fluid communication passage between a space in the lower clearance
sandwiched between the second and third sealing bodies and an
inside space of the cowling.
8. The lubricant pump seal of claim 7, wherein the pump casing
comprises a casing body enclosing the pump chamber and supporting
the first and second sealing bodies, and a separate casing member
secured to a lower surface of the casing body and supporting the
third and fourth sealing bodies, an upper surface of the casing
member including a groove, wherein at least a portion of the
passage comprises the groove.
9. The lubricant pump seal of claim 7, wherein the pump casing
comprises a casing body enclosing the pump chamber and supporting
the first and second sealing bodies, and a separate casing member
secured to a lower surface of the casing body and supporting the
third and fourth sealing bodies, a lower surface of the casing body
including a groove, wherein at least a portion of the passage
comprises the groove.
10. An outboard motor comprising an internal combustion engine, a
propulsion unit driven by the engine, a housing enclosing the
engine and at least a portion of the propulsion unit, a drive shaft
extending between the engine and the propulsion unit, a lubricant
pump unit configured to deliver lubricant to the engine, the
lubricant pump unit including a pump casing and a pump chamber
defined within the casing, the drive shaft extending through the
lubricant pump unit, a seal disposed between the lubricant pump
unit and the drive shaft, and means for using a fluid other than
lubricant for relieving a negative pressure generated within the
pump casing in the vicinity of the seal but outside of the pump
chamber.
11. An outboard motor comprising an internal combustion engine, a
propulsion unit driven by the engine, a housing enclosing the
engine and at least a portion of the propulsion unit, a drive shaft
extending between the engine and the propulsion unit, a lubricant
pump unit comprising a pump chamber and being configured to deliver
lubricant to the engine, the drive shaft extending through the
lubricant pump unit, a clearance defined between the drive shaft
and the lubricant pump unit, at least one seal in contact with the
drive shaft and configured to seal the interior of the lubricant
pump unit from an exterior of the pump unit, the seal being
disposed between a portion of the clearance and the pump chamber,
and a passage extending from the portion of the clearance to the
exterior of the lubricant pump unit to allow air to bypass all of
the seals in contact with the drive shaft and to flow into the
portion of the clearance.
12. An outboard motor comprising an internal combustion engine, a
propulsion unit driven by the engine, a housing enclosing the
engine and at least a portion of the propulsion unit, a drive shaft
extending between the engine and the propulsion unit, a lubricant
pump unit configured to deliver lubricant to the engine, the drive
shaft extending through the lubricant pump unit, a clearance
defined between the drive shaft and the lubricant pump unit, at
least one seal in contact with the drive shaft and configured to
seal the interior of the lubricant pump unit from an exterior of
the pump unit, and a passage extending from the clearance to
exterior of the lubricant pump unit, wherein the passage extends to
a source of dry air within the housing.
13. The outboard motor according to claim 11 additionally
comprising a lubricant reservoir, wherein the passage extends to at
least one of the lubricant reservoir, an internal cavity of the
engine, and an enclosed space defined at least partially by the
housing.
14. The outboard motor according to claim 13, wherein the passage
extends to the lubricant reservoir and the space defined at least
partially by the housing.
15. The outboard motor according to claim 14 additionally
comprising a plug disposed in the passage blocking communication to
the space defined at least partially by the housing.
16. A method of preventing moisture penetration into an interior of
a lubricant pump of an outboard motor, the lubricant pump
comprising a pump casing and a pump chamber, the method comprising
providing a fluid communication passage between the pump chamber
and a lubricant reservoir, generating negative pressure within the
interior of the pump casing outside of the pump chamber, channeling
fluid from a location above the level of liquid lubricant in the
lubricant reservoir to the pump casing, thereby eliminating the
negative pressure.
17. A method of preventing moisture penetration into an interior of
a lubricant pump of an outboard motor, the lubricant pump
comprising a pump casing and a pump chamber, the method comprising:
providing a fluid communication passage between the interior of the
lubricant casing at a point outside the pump chamber and a space
inside a cowling, generating negative pressure at the point within
the pump casing, channeling fluid from the space inside the
cowling, but not inside the a lubricant reservoir, to the point
within the pump casing, thereby eliminating the negative pressure.
Description
PRIORITY INFORMATION
[0001] This application claims priority to Japanese Patent
Application No. 2001-251912, filed on Aug. 22, 2001, the entire
contents of which are hereby expressly incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to outboard motors for
watercraft, and in particular, a lubricant pump seal for outboard
motors.
[0004] 2. Description of the Related Art
[0005] Outboard motors containing internal combustion engines are
commonly used for powering watercraft. A housing, which is mounted
to a transom of the watercraft, typically encloses the engine.
Rotation of an output shaft of the internal combustion engine
drives a driveshaft. The driveshaft drives a water propulsion
device, such as a propeller. When the watercraft operates, the
propeller is submerged beneath a water surface. Rotation of the
propeller moves the watercraft across the water surface.
[0006] Internal combustion engines require lubricant for normal
operation. Four-cycle engine typically employ a recirculating type
of lubrication system. In such a system, a lubricant pump supplies
lubricant to a crank chamber and other moving components of the
engine. The lubricant pump also circulates lubricant between the
crank chamber and a lubricant pan. The lubricant pump is usually
located near the coupling of the output shaft and the driveshaft,
so that the rotation of the output shaft can be used to drive the
lubricant pump.
[0007] The lubricant pump typically comprises a pump casing
defining a pump chamber. The drive shaft penetrates the pump
chamber. A first sealing body seals an upper clearance formed
between an upper part of the pump casing and the drive shaft.
Second and third sealing bodies seal a lower clearance formed
between a lower part of the pump casing and the drive shaft.
[0008] The outboard motor interfaces with the body of water upon
which the watercraft moves. Lubricant exiting the motor pollutes
the body of water. Ideally the outboard motor operates as cleanly
as possible in order to protect our limited natural resources. The
first and second sealing bodies typically prevent lubricant from
exiting the pump casing.
[0009] Often, the motor draws in water from the surrounding body of
water for cooling the engine and an exhaust system. However, water
penetrating the coupling of the output shaft and driveshaft
adversely affects the performance and longevity of the engine.
Impurities in the water, especially salt, deposit on the shafts and
cause corrosion. The corrosion causes the shafts to stick together.
The third sealing body is designed to prevent water from entering
the pump casing.
[0010] However, during operation, the lubricant pump creates
negative pressure in the region of the coupling. This negative
pressure draws in ambient air and water. The water and moisture
contained in the air causes corrosion. Prior attempts at preventing
moisture penetration due to negative pressure in the pump chamber
have been unsuccessful.
SUMMARY OF THE INVENTION
[0011] The preferred embodiments of the present lubricant pump seal
for an outboard motor have several features, no single one of which
is solely responsible for their desirable attributes. Without
limiting the scope of this lubricant pump seal for outboard motor
as expressed by the claims that follow, certain features are
described below. After considering this discussion, and
particularly after reading the section entitled "Detailed
Description of the Preferred Embodiments," one will understand how
the features of the preferred embodiments provide advantages, which
include reliable prevention of water penetration into an interior
of the lubricant pump.
[0012] One aspect of the present invention includes the realization
that negative pressure developed by lubricant pump can be relieved,
thereby preventing the lubricant pump from drawing humid air or
water into the lubricant pump. One preferable way of relieving the
pressure is to provide a passage extending from the lubricant pump
to a source of dry air. By constructing in the lubricant pump as
such, water infiltration into the lubricant pump can be
prevented.
[0013] In accordance with one preferred embodiment of the present
invention, a lubricant pump seal is provided for an outboard motor.
The outboard motor comprises a an internal combustion engine, a
water propulsion device, a drive shaft configured to transmit
torque from the engine to the water propulsion device, and a
lubricant pump configured to supply lubricant to the internal
combustion engine. The lubricant pump includes a pump casing
enclosing a pump chamber. The drive shaft extends through the pump
casing. A rotor is housed in the pump chamber for rotation with the
drive shaft. A first sealing body for sealing an upper clearance is
formed between an upper part of the pump casing and the drive
shaft. Second and third sealing bodies for sealing a lower
clearance are formed between a lower part of the pump casing and
the drive shaft. A fourth sealing body is disposed between the
second and third sealing bodies in an axial direction of the drive
shaft. The fourth sealing body seals the lower clearance.
[0014] The lubricant pump seal preferably further comprises a fluid
communication passage between a space in the lower clearance
sandwiched between the second and third sealing bodies and a
lubricating oil reservoir inside the internal combustion engine. At
least a portion of the passage may comprise a groove in an
auxiliary pump casing. Alternatively, at least a portion of the
passage may comprise a groove in a lower surface of a casing
body.
[0015] The lubricating oil reservoir may comprise a crank chamber
of the engine. Alternatively, the lubricating oil reservoir may
comprise a lubricant pan located below a crank chamber of the
engine.
[0016] The lubricant pump seal preferably further comprises a fluid
communication passage between a space in the lower clearance
sandwiched between the second and third sealing bodies and an
inside space of the cowling. At least a portion of the passage may
comprise a groove in an auxiliary pump casing. Alternatively, at
least a portion of the passage may comprise a groove in a lower
surface of a casing body.
[0017] Another aspect of the present invention includes a method of
preventing moisture penetration into an interior of a lubricant
pump of an outboard motor. The method comprises providing a fluid
communication passage between the interior of the lubricant pump
and a lubricant reservoir, generating negative pressure within the
interior of the lubricant pump, and channeling fluid from the
lubricant reservoir to the interior of the lubricant pump, thereby
eliminating the negative pressure.
[0018] Yet another aspect of the present invention is directed to a
method of preventing moisture penetration into an interior of a
lubricant pump of an outboard motor. The method comprises the steps
of providing a fluid communication passage between the interior of
the lubricant pump and a space inside a cowling, generating
negative pressure within the interior of the lubricant pump, and
channeling fluid from the space inside the cowling to the interior
of the lubricant pump, thereby eliminating the negative pressure.
In accordance with a further aspect of the present invention, an
outboard motor comprises an internal combustion engine, a
propulsion unit driven by the engine, and a housing enclosing the
engine and at least a portion of the propulsion unit. A drive shaft
extends between the engine and the propulsion unit. A lubricant
pump unit is configured to deliver lubricant to the engine. The
drive shaft extends through the lubricant pump unit. A seal is
disposed between the lubricant pump unit and the drive shaft.
Additionally, the outboard motor includes means for relieving a
negative pressure generated in the vicinity of the seal.
[0019] In accordance with yet another aspect of the present
invention, an outboard motor comprises an internal combustion
engine, a propulsion unit driven by the engine, and a housing
enclosing the engine and at least a portion of the propulsion unit.
A drive shaft extends between the engine and the propulsion unit. A
lubricant pump unit is configured to deliver lubricant to the
engine. The drive shaft extends through the lubricant pump unit. A
clearance is defined between the drive shaft and the lubricant pump
unit. At least one seal is in contact with the drive shaft and is
configured to seal the interior of the lubricant pump unit from an
exterior of the pump unit. A passage extends from the clearance to
exterior of the lubricant pump unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The preferred embodiments of the lubricant pump seal for
outboard motor, illustrating its features, will now be discussed in
detail. These embodiments depict the novel and non-obvious
lubricant pump seal for outboard motor shown in the accompanying
drawings, which are for illustrative purposes only. These drawings
include the following figures, in which like numerals indicate like
parts:
[0021] FIG. 1 is a side elevational view of an outboard motor
constructed in accordance with the present invention, with certain
features including an engine, driveshaft, and transmission shown in
phantom;
[0022] FIG. 2 is an enlarged partial sectional view of the outboard
motor of FIG. 1 illustrating a lubricant pump therein, taken along
a vertical plane passing through a rotational axis of the drive
shaft and extending generally fore to aft;
[0023] FIG. 3 is a partial cross-sectional view of the outboard
motor of FIG. 1 taken along line 3-3 in FIG. 2;
[0024] FIG. 4 is a partial cross-sectional view of the outboard
motor of FIG. 1, taken along line 4-4 in FIG. 3 and illustrating
the lubricant pump and a seal;
[0025] FIG. 5 is a partial cross-sectional view of a modification
of the outboard motor of FIG. 1 illustrating a lubricant pump
therein, taken along a vertical plane passing through a rotational
axis of the drive shaft and extending generally fore to aft;
[0026] FIG. 6 is a cross-sectional view of the outboard motor of
FIG. 5, taken along line 6-6 in FIG. 5; and
[0027] FIG. 7 is an enlarged partial cross-sectional view of a
further modification of the outboard motor shown in FIGS. 1-6,
taken along a vertical plane passing through a rotational axis of
the driveshaft and extending generally fore to aft.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] With reference to FIG. 1, an overall configuration of an
outboard motor is described below to assist the reader's
understanding of a preferred environment of use. However, it is
apparent to one of ordinary skill in the art that the lubricant
pump and associated components described below can be used in other
vehicles, such as, for example, but without limitation, personal
watercraft, jet boats, off-road vehicles, and other vehicles.
Additionally, The outboard motor is described in reference to a
coordinate system wherein a longitudinal axis extends from fore to
aft and a lateral axis from port side to starboard side normal to
the longitudinal axis. In addition, relative heights are expressed
as elevations in reference to the under surface of the watercraft
30. In various figures, an arrow denoted with the legend "forward"
is used to denote the direction in which the watercraft travels
during normal forward operation
[0029] FIG. 1 illustrates a watercraft 10 comprising a hull 12
floating on a water surface 14. The arrow F indicates a forward
direction of travel of the watercraft 10. The watercraft 10
includes an outboard motor 16. A clamping bracket 18 secures the
outboard motor 16 to the hull 12.
[0030] A casing houses the components of the outboard motor 16. The
casing includes a lower portion 20, which is submerged beneath the
water surface 14, an intermediate portion 22 extending generally
vertically from the lower portion 20, and an upper portion 24
extending generally vertically from the intermediate portion 22. An
exhaust guide 26 extends through portions of the intermediate
portion 22 and upper portion 24. The exhaust guide 26 can be
configured to selectively open and close an opening at an upper end
of the intermediate portion 22.
[0031] The upper portion 24 comprises a cowling 28, which is
generally constructed of a sturdy plastic. The cowling 28 contains
an internal combustion engine 30, which generates power to propel
the watercraft 10 across the water surface 14. The engine 30
includes a plurality of pistons (not shown) that reciprocate within
their respective cylinders (not shown) in response to combustion
reactions in each cylinder. Each piston is connected, via a piston
rod, to a crankshaft 32, which is housed in a crank chamber 34 of a
crankcase 36. The reciprocating motion of the pistons turns the
crankshaft 32, which turns a vertically extending driveshaft 38. A
lower portion of the crankcase 36 comprises a lubricant reservoir
40. Lubricant from the lubricant reservoir 40 is supplied to the
moving parts in the crank chamber 34, an other components of the
engine 30, described in greater detail below.
[0032] The driveshaft 38, having an axis of rotation 42, extends
from the upper portion 24, through the intermediate portion 22 and
into the lower portion 20. An upper portion of the driveshaft 38 is
rotatably connected to the crankshaft 32. In the illustrated
embodiment, an outer surface of the upper end of the driveshaft 38
includes splines 46 (FIG. 2) which engage splines formed on an
inner diameter of the crankshaft 32.
[0033] With reference to FIG. 2, a cylindrical body 44 is rotatably
connected to the driveshaft 38 for rotation with one another. In
the illustrated embodiment, an outer surface of the drive shaft 38
includes another set of splines 47 arranged below the splines 46.
The splines 47 engage splines disposed on an inner surface of the
cylindrical body 44. The cylindrical body 44 extends downward along
the axis of rotation 42 toward a lower end of a pump casing 48,
which is described in detail below.
[0034] The driveshaft body 50 extends downward from the cylindrical
body 44 along the axis of rotation 42. A lower end of the
driveshaft body 50 is operably connected to a propeller shaft 52
(FIG. 1). The propeller shaft 52 extends generally parallel to the
water surface 14, and includes a propeller 54 mounted to a rear end
thereof. The propeller 54 rotates with the propeller shaft 52,
generating force on the water. The reaction force of the water upon
the propeller 54 propels the watercraft 10 across the water surface
14.
[0035] The outboard motor 16 includes a trochoid-type lubricant
pump 56, which is illustrated in detail in FIGS. 2-4. The lubricant
pump 56 circulates lubricant 58 (FIG. 3) from the lubricant
reservoir 40 to portions of the engine 30 that benefit from
lubrication, such as, for example, but without limitation,
crankshaft bearings, cylinder walls, piston pins, and valvetrain
components. The pump casing 48, which is located on top of the
exhaust guide 26, encloses the lubricant pump 56 (FIGS. 2 and 3).
An interior portion of the pump casing 48 comprises a pump chamber
60. A portion of the cylindrical body 44 within the pump chamber 60
includes a rotor 62 (FIG. 3). The rotor 62 rotates with the
cylindrical body 44 about the axis of rotation 42.
[0036] As illustrated in FIG. 3, the pump casing 48 includes a
lubricant intake port 64. The lubricant pump 56 draws lubricating
oil 58 from the lubricant reservoir 40 through the lubricant intake
port 64 and into the pump chamber 60. The lubricant pump 56 expels
the oil 58 through a lubricant delivery port 66 to portions of the
engine 30 that require lubrication. The lubricating oil 58 flows
downward under the influence of gravity and returns to the
lubricant reservoir 40 (FIG. 3).
[0037] An upper wall 68 of the pump casing 48 includes a
through-hole 70 (FIG. 2) that is centered on the axis of rotation
42. Similarly, a lower wall 72 of the pump casing 48 includes a
through-hole 74 (FIG. 2) that is centered on the axis of rotation
42. A lower pump casing 76 is secured to a lower surface of the
pump casing 48 around the lower through-hole 74. The lower pump
casing 76 is annular, including a through-hole 78 (FIGS. 2 and 4)
that is centered about the axis of rotation 42. Preferably the
lower pump casing 76 is secured to the pump casing 48 with
fastening members (not shown). A gasket (not shown) disposed
between the pump casing 48 and the lower pump casing 76 seals the
junction between the pump casing 48 and the lower pump casing
76.
[0038] The driveshaft body 50 extends through both the upper and
lower through-holes 70, 74 and through the through-hole 78 in the
lower pump casing 76 (FIG. 2). The cylindrical body 44 extends
through the upper and lower through-holes 70, 74. A lower end of
the cylindrical body 44 is located within an annular lower
clearance 80, or interior region between the pump casing 48 and the
auxiliary pump casing 76 (FIG. 4). A first sealing body 82 seals an
annular upper clearance 84 (FIG. 2) between an inner
circumferential surface of the upper through-hole 70 and an outer
circumferential surface of the cylindrical body 44.
[0039] Second and third sealing bodies 86, 88 seal the annular
lower clearance 80 (FIG. 4). The second sealing body 86 is located
between an inner circumferential surface of the lower through-hole
74 and an outer circumferential surface of the cylindrical body 44.
The third sealing body 88 is located between an inner
circumferential surface of the through-hole 78 in the lower pump
casing 76 and an outer circumferential surface of the driveshaft
body 50. A fourth sealing body 90 is located between the second and
third sealing bodies 86, 88 preferably on an annular shoulder 92
defined by the lower pump casing 76. The fourth sealing body 90
assists the second and third sealing bodies 86, 88 to seal the
lower clearance 80.
[0040] With reference to FIG. 4, each sealing body 82, 86, 88, 90
comprises a metal annular frame 94 (FIG. 1) press-fit in the inside
circumferential surface of its respective through hole 70, 74, 78
and shoulder 92. An elastic rubber sealing lip 96 is secured to the
annular frame 94, for example, by vulcanization. The lip 96
protrudes from the annular frame 94 toward the driveshaft 38, and
abuts in sliding contact the outside circumferential surface of the
driveshaft 38. An annular spring 98 fitted on the sealing lip 96 to
bias the sealing lip 96 toward the outside circumferential surface
of the driveshaft 38, thus increasing a strength of contact between
the sealing lip 96 and the driveshaft 38 or cylindrical member
44.
[0041] The sealing lips 96 of the first and second sealing bodies
82, 86 protrude obliquely upwardly from the annular frames 94. The
second sealing body 86 effectively prevents the lubricating oil 58
in the pump chamber 60 from leaking to the outside below the pump
casing 48 through the lower clearance 80.
[0042] The sealing lips 96 of the third and fourth sealing bodies
88, 90 protrude obliquely downwardly from the annular frames 94
(FIG. 1). The third and fourth sealing bodies 88, 90 reliably
prevent water below the pump casing 48 from entering the pump
chamber 60 through the lower clearance 80.
[0043] While operating, the lubricant pump 56 generates negative
pressure in a space 100 (FIG. 4) in the lower clearance 80 between
the second and third sealing bodies 86, 88. This negative pressure
tends to draw in air and moisture through the through-hole 78 in
the auxiliary pump casing 76, leading to the problems described
above. To relieve the negative pressure and thus prevent the
negative pressure from drawing in air and moisture through the
through-hole 78 in the lower pump casing 76, the pump casing 48
includes a passage 102 extending between the space 100 and the
lubricant reservoir 40. Thus, the negative pressure in the space
100 generated by the lubricant pump 56 draws air from the lubricant
reservoir 40, through the passage 102 and into the space 100. Since
the air in the lubricant reservoir 40 is relatively dry, very
little moisture travels to the space 100 through the passage 102.
Alternatively, the passage 102 can connect the space 100 with an
interior space 104 of the cowling 28, which also contains dry
air.
[0044] A first portion of the passage 102 comprises a radial groove
106 (FIGS. 3 and 4) formed in an upper surface of the lower pump
casing 76. A second portion of the passage 102 comprises a first
vertical bore 108 in the lower surface 72 of the pump casing 48. A
lower opening of the first vertical bore 108 adjoins the groove
106. A third portion of the passage 102 comprises a horizontal bore
110 in the pump casing 48 that extends from an upper end of the
first vertical bore 108, through a wall of the pump casing 48 to an
interior space 104 of the cowling 28. A fourth portion of the
passage 102 comprises a second vertical bore 112 in the lower
surface 72 of the pump casing 48. The second vertical bore 112
extends upward from the lower surface 72 to the horizontal bore
110.
[0045] With reference to FIG. 4, the passage 102 extends from the
space 100, through the groove 106 in the auxiliary pump casing 76,
into a lower end of the first vertical bore 108, from an upper end
of the first vertical bore 108 through the horizontal bore 110,
into an upper end of the second vertical bore 112 and downward
through a lower end of the second vertical bore 112. The lower end
of the second vertical bore 112 adjoins a vertical bore 114 in the
exhaust guide 26, which is in fluid communication with the
lubricant reservoir 40. Thus, the space 100 is in fluid
communication with the lubricant reservoir 40 through the passage
102.
[0046] When the lubricant pump 56 generates negative pressure in
the space 100, air is drawn out of the lubricant reservoir 40,
through the vertical bore 114 in the exhaust guide 26, through the
passage 102 and into the space 100 (in the direction of the
solid-line arrows in FIG. 1). Since the air in the lubricant
reservoir 40 is dry, the fluid path from the lubricant reservoir 40
to the space 100 created by the passage 102 reliably prevents
moisture from penetrating the space 100. Additionally, the air in
the lubricant reservoir, above the level of liquid lubricant, can
include oil vapors entrained therein, which can help displace water
vapors. Without the fluid path, air and moisture would tend to be
drawn in from the ambient through the third and fourth seals 88,
90.
[0047] A seal 116 can be mounted at the at the end of the
horizontal bore 110 adjacent the wall of the pump casing 48 to
ensure that the space 100 is in fluid communication with the
lubricant reservoir 40 only. If desired, the seal 116 may be
removed such that the space 100 is in fluid communication with both
the lubricant reservoir 40 and the interior space 104 of the
cowling 28. Alternatively, the seal 116 and the second vertical
bore 112 need not be provided, such that the space 100 is in fluid
communication with the interior space 104 of the cowling 28
only.
[0048] Advantageously, the groove 106 is relatively easy and
inexpensive to manufacture. Thus, the groove 106 lessens the
complexity and cost of manufacturing the lubricant pump 56 while
still reliably preventing moisture from penetrating the interior of
the lubricant pump 56. Those of skill in the art will appreciate
that the groove 106 could be formed in the lower surface 72 of the
pump casing 48, rather than in the lower pump
[0049] FIGS. 5 and 6 illustrate a modification of the present
lubricant pump seal arrangement described above with reference to
FIGS. 1-4. The pump seal arrangement illustrated in FIGS. 5 and 6,
and described below, is substantially identical to the embodiment
described above, except as noted below.
[0050] In the modification of FIGS. 5 and 6, the lower pump casing
76 is shape substantially as a plate, and is sandwiched between a
lower surface 118 of the crankcase 36 and the upper surface 120 of
the exhaust guide 26 (FIG. 5). The crankcase 36, lower pump casing
76 and exhaust guide 26 are all fixed together.
[0051] An upper surface of the lower pump casing 76 includes a
groove 106 comprising a portion of a passage 102 (FIGS. 5 and 6).
The passage 102 extends from the space 100 in the lower clearance
80, through the groove 106, and into a diagonally oriented bore 122
(FIG. 5). The diagonally oriented bore 122 extends through the
lower pump casing 76 and the exhaust guide 26. A lower end of the
diagonal bore 122 is in fluid communication with the lubricant
reservoir 40.
[0052] The passage 102 thus extends from the space 100 in the lower
clearance 80, through the groove 106, and through the diagonal bore
122 in the auxiliary pump casing 76 and exhaust guide 26 into the
lubricant reservoir 40. Just as with the previous embodiment,
negative pressure in the space 100 draws dry air out of the
lubricant reservoir 40, through the passage 102 and into the space
100.
[0053] FIG. 7 illustrates another modification of the lubricant
pump seal arrangement of FIGS. 1-4. In this modification, the pump
casing 48 is fixed to the bottom of the crankcase 36. The lower
pump casing 76 includes a horizontal bore 110 through a side wall
that extends to the space 100. Preferably, a seal 116 closes the
hole in the side wall. A vertical bore 114 extends downward from a
lower wall of the crank chamber 34 through the crankcase 36,
through the pump casing 48, through the lower pump casing 76 and
intersects the horizontal bore 110. The bores thus create a passage
102 that brings the space 100 into fluid communication with the
crank chamber 34 in which lubricant collects before returning to
the lubricant reservoir 40. Negative pressure generated in the
space 100 draws lubricant or air out of the crank chamber 34,
through the passage 102 and into the space 100.
SCOPE OF THE INVENTION
[0054] The above presents a description of the best mode
contemplated for carrying out the present lubricant pump seal for
outboard motor, and of the manner and process of making and using
it, in such full, clear, concise, and exact terms as to enable any
person skilled in the art to which it pertains to make and use this
lubricant pump seal for outboard motor. This lubricant pump seal
for outboard motor is, however, susceptible to modifications and
alternate constructions from that discussed above that are fully
equivalent. Consequently, this lubricant pump seal for outboard
motor is not limited to the particular embodiments disclosed. On
the contrary, this lubricant pump seal for outboard motor covers
all modifications and alternate constructions coming within the
spirit and scope of the lubricant pump seal for outboard motor as
generally expressed by the following claims, which particularly
point out and distinctly claim the subject matter of the lubricant
pump seal for outboard motor.
* * * * *